Methods For Using Synthetic Triterpenoids In The Treatment Of Bone Or Cartilage Diseases Or Conditions

Abstract

The present invention features the use of a synthetic triterpenoid to induce gene expression and differentiation of stem or progenitor cells in the treatment of bone/cartilage diseases or conditions.

Description

INTRODUCTION

[0001] This patent application is a continuation of U.S. application Ser. No. 13/466,473 filed May 8, 2012, which claims the benefit of priority from U.S. Provisional Application Ser. No. 61/629,298, filed Nov. 15, 2011, and is a continuation-in-part application of U.S. application Ser. No. 11/941,723, filed Nov. 16, 2007, now issued as U.S. Pat. No. 8,299,046, which claims the benefit of priority from U.S. Provisional Application Ser. No. 60/866,344, filed Nov. 17, 2006, the content of each of which is herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] Triterpenoids, biosynthesized in plants by the cyclization of squalene, are used for medicinal purposes in many Asian countries; and some, like ursolic and oleanolic acids, are known to exhibit anti-inflammatory and anti-carcinogenic activity (Huang, et al. (1994) Cancer Res. 54:701-708; Nishino, et al. (1988) Cancer Res. 48:5210-5215). However, the biological activity of these naturally-occurring molecules is relatively weak, and therefore the synthesis of new analogs to enhance their potency has been undertaken (Honda, et al. (1997) Bioorg. Med. Chem. Lett. 7:1623-1628; Honda, et al. (1998) Bioorg. Med. Chem. Lett. 8(19):2711-2714). An ongoing effort for the improvement of anti-inflammatory and antiproliferative activity of oleanolic and ursolic acid analogs led to the discovery of 2-cyano-3,12-dioxooleane-1,9(11)-dien-28-oic acid (CDDO) and related compounds (Honda, et al. (1997) supra; Honda, et al. (1998) supra; Honda, et al. (1999) Bioorg. Med. Chem. Lett. 9(24):3429-3434; Honda, et al. (2000) J. Med. Chem. 43:4233-4246; Honda, et al. (2000) J. Med. Chem., 43:1866-1877; Honda, et al. (2002) Bioorg. Med. Chem. Lett. 12:1027-1030; Suh, et al. (1998) Cancer Res. 58:717-723; Suh, et al. (1999) Cancer Res., 59(2):336-341; Suh, et al. (2003) Cancer Res. 63:1371-1376; Place, et al. (2003) Clin. Cancer Res. 9:2798-2806; Liby, et al. (2005) Cancer Res. 65:4789-4798). Several potent derivatives of oleanolic acid were identified, including methyl-2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO-Me).

[0003] CDDO-Me suppresses the induction of several important inflammatory mediators, such as iNOS, COX-2, TNF.alpha., and IFN.gamma., in activated macrophages. CDDO-Me has also been reported to activate the Keap1/Nrf2/ARE signaling pathway resulting in the production of several anti-inflammatory and antioxidant proteins, such as heme oxygenase-1 (HO-1). These properties have made CDDO-Me a candidate for the treatment of neoplastic and proliferative diseases, such as cancer. Moreover, synthetic triterpenoids have been found to induce apoptosis and differentiation and inhibit proliferation in human leukemia cells (Ikeda, et al. (2003) Cancer Res. 63:5551-5558; Konopleva, et al. (2002) Blood 99(1):326-335; Suh, et al. (1999) supra; Ito, et al. (2000) Mech. Dev. 97:35-45), induce osteoblastic differentiation in osteosarcoma cells (Ito, et al. (2001) Antimicrob. Agents Chemother. 45:1323-1336), enhance neuronal growth factor-induced neuronal differentiation of rat PC12 pheochromocytoma cells, and induce adipogenic differentiation of fibroblasts into adipocytes (Suh, et al. (1999) supra). CDDO-Me has also been found an effective drug for improving kidney function in patients suffering for renal/kidney disease using CDDO-Me (U.S. Pat. No. 8,129,429).

SUMMARY OF THE INVENTION

[0004] The present invention encompasses the finding that certain triterpenoid compounds induce stem or progenitor cell differentiation. The invention encompasses the specific finding that certain such triterpenoid compounds alter gene expression in stem or progenitor cells. The invention therefore provides methods and reagents for inducing stem or progenitor cell differentiation, in a variety of important contexts and applications.

[0005] Among other things, the present invention provides methods for producing a stem or progenitor cell with induced gene expression by contacting a stem or progenitor cell with an effective amount of a synthetic triterpenoid to induce the expression of one or more of SOX9 (Sex determining region Y-box 9), COL2A1 (Type II Collagen (alpha1)), TGF-.beta.1, TGF-.beta.2, TGF-.beta.3, BMP2, BMP4, BMPRII (Bone Morphogenic Protein Receptor II), SMAD (Small Mothers Against Decapentaplegic) 3, SMAD4, SMAD6, SMAD7, TIMP (Tissue Inhibitor of Metalloproteinase)-1 or TIMP-2 in the stem or progenitor cell, wherein the stem or progenitor cell is a mesenchymal stem cell, adipose tissue-derived mesenchymal stem cell, embryonic stem cell, stem cell from exfoliated deciduous teeth, periosteum cell, osteoprogenitor cell, or growth plate progenitor cell. In one embodiment, the stem or progenitor cell is multipotent.

[0006] A stem or progenitor cell produced by the method is also provided, as are methods of using such cells in the treatment of a degenerative disease, disorder, condition, or injury such as bone injury, cartilage injury, joint injury, dental disease, osteoarthritis, rheumatoid arthritis, degenerative disc disease, kyphosis, or osteopenia. In addition, treatment of a congenital disorder such as scoliosis or a skeletal disorder is also provided.

[0007] Methods for treating a degenerative disease or injury or a congenital disorder by administering to a patient an effective amount of a synthetic triterpenoid are also provided.

DETAILED DESCRIPTION OF THE INVENTION

[0008] It has now been shown that certain synthetic triterpenoid compounds induce the expression of SOX9, COL2A1, TGF-.beta.1, TGF-.beta.2, TGF-.beta.3, BMP2, BMP4, BMPRII, SMAD3, SMAD4, SMAD6, SMAD7, TIMP-1 and/or TIMP-2 in stem cells. For example, the synthetic triterpenoids CDDO-Im and CDDO-EA induce the expression of each of the above-referenced genes in mesenchymal stem cells and induce chondrogenesis in newborn mouse calvaria. In this respect, the present invention provides methods of using such synthetic triterpenoid compounds to produce stem/progenitor cells with altered expression of one or more of SOX9, COL2A1, TGF-.beta.1, TGF-.beta.2, TGF-.beta.3, BMP2, BMP4, BMPRII, SMAD3, SMAD4, SMAD6, SMAD7, TIMP-1 or TIMP-2, as compared to a control (e.g., a cell not contacted with the synthetic triterpenoid), and application of such cells in the prevention or treatment of disease, where the cells can contacted with the triterpenoid in situ, in vivo, ex vivo or in vitro. In some embodiments, expression of one or more of said genes is indicative of differentiation of the stem/progenitor cell.

[0009] As is known in the art, stem cells are primal cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types. Mammalian stem cells include embryonic stem cells, derived from blastocysts; adult stem cells, which are found in adult tissues; and cord blood stem cells, which are found in the umbilical cord. In a developing embryo, stem cells can differentiate into all of the specialized embryonic tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing specialized cells. As stem cells can be grown and transformed into specialized cells with characteristics consistent with cells of various tissues such as muscles or nerves through cell culture, stem cells are of use in medical therapies.

[0010] "Potency" specifies the differentiation potential (the potential to differentiate into different cell types) of the stem cell. Totipotent stem cells are produced from the fusion of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg are also totipotent. These cells can differentiate into embryonic and extraembryonic cell types. Pluripotent stem cells are the descendants of totipotent cells and can differentiate into cells derived from any of the three germ layers. Multipotent stem/progenitor cells can produce only cells of a closely related family of cells (e.g., hematopoietic stem cells differentiate into red blood cells, white blood cells, platelets, etc.).

[0011] The term "differentiation" or "differentiated," as used herein, refers to the developmental process wherein an unspecialized or less specialized cell becomes more specialized for a specific function, such as, for example, the process by which a mesenchymal stem cell becomes a more specialized cell such as a cartilage cell, a bone cell, a muscle cell, or a fat cell. Differentiation can be assessed by identifying lineage-specific markers, such as, for example, aggrecan, a proteoglycan specific for cartilage.

[0012] Embryonic stem (ES) cell lines are cultures of cells derived from the epiblast tissue of the inner cell mass (ICM) of a blastocyst. A blastocyst is an early stage embryo, approximately 4 to 5 days old in humans and composed of 50-150 cells. ES cells are pluripotent, and give rise during development to all derivatives of the three primary germ layers: ectoderm, endoderm and mesoderm. In other words, they can develop into each of the more than 200 cell types of the adult body when given sufficient and necessary stimulation for a specific cell type. They do not contribute to the extra-embryonic membranes or the placenta.

[0013] A human embryonic stem cell is defined by the presence of several transcription factors and cell surface proteins. The transcription factors Oct-4, Nanog, and Sox2 form the core regulatory network, which ensures the suppression of genes that lead to differentiation and the maintenance of pluripotency. The cell surface proteins most commonly used to identify hES cells are the glycolipids SSEA3 and SSEA4 and the keratan sulfate antigens Tra-1-60 and Tra-1-81. Because of the combined ability of unlimited expansion and pluripotency, embryonic stem cells remain a potential source for regenerative medicine and tissue replacement after injury or disease. Therefore, the present invention contemplates the use of embryonic stem cells. Cells derived from embryonic sources may include embryonic stem cells or stem cell lines obtained from a stem cell bank or other recognized depository institution.

[0014] An adult or somatic stem cell, a cell which is found in a developed organism, has two properties: the ability to divide and create another cell like itself, and also divide and create a cell more differentiated than itself. Adult stem cell treatments have been used for many years to successfully treat leukemia and related bone/blood cancers through bone marrow transplants. Therefore, in particular embodiments of the present invention, adult stem cells are used in the methods of the disclosed herein. Pluripotent adult stem cells are rare and generally small in number but can be found in a number of tissues including umbilical cord blood. Most adult stem cells are lineage restricted (multipotent). Therefore, in certain embodiments, the adult stem cells of the invention are multipotent.

[0015] Adult stem cells have been identified in many organs and tissues, including brain, bone marrow, peripheral blood, blood vessels, skeletal muscle, skin, teeth, heart, gut, liver, ovarian epithelium, and testis, and are thought to reside in a specific area of each tissue (called a "stem cell niche"). In this respect, stem cells are generally referred by the tissue from which they are derived, e.g., cardiac stem cells are stems that naturally reside within the heart, adipose-derived stem cells are stem cells found in fat tissue, myoblasts are muscle stem cells, dental pulp stem cells are found in the teeth, etc.

[0016] Stem cells give rise to a number of different cell types. For example, mesenchymal stem cells (CD105.sup.+, CD90.sup.+, CD11b.sup.+, CD34.sup.+ and CD45.sup.+) give rise to bone cells (osteocytes), cartilage cells (chondrocytes), fat cells (adipocytes), and other kinds of connective tissue cells such as those in tendons. Hematopoietic stem cells (Lin.sup.-, CD34.sup.+, CD90.sup.+, CD34.sup.- and CD45.sup.-) give rise to all the types of blood cells including red blood cells, B lymphocytes, T lymphocytes, natural killer cells, neutrophils, basophils, eosinophils, monocytes, and macrophages. Neural stem cells in the brain (CD133.sup.+, FA-1.sup.+, CD34.sup.- and CD45.sup.-) give rise to nerve cells (neurons), astrocytes and oligodendrocytes. Epithelial stem cells in the lining of the digestive tract occur in deep crypts and give rise to several cell types including absorptive cells, goblet cells, paneth cells, and enteroendocrine cells. Skin stem cells occur in the basal layer of the epidermis and at the base of hair follicles, and give rise to keratinocytes, which migrate to the surface of the skin and form a protective layer. The follicular stem cells can give rise to both the hair follicle and to the epidermis. Neural crest stem cells (p75 receptor.sup.+, .alpha..sub.4 integrin receptor.sup.+, CD29.sup.+ and CD9.sup.+) differentiate into the cells of the peripheral nervous system. In some embodiments, the invention includes the use of mesenchymal stem cells, adipose tissue-derived mesenchymal stem cells, embryonic stem cells or stem cells from exfoliated deciduous teeth.

[0017] Progenitor cells are cells that are direct descendants of stem cells, are typically less potent than stem cells, and have diminished capacity for self-renewal relative to stem cells, but retain the ability to become at least one, if not multiple, cell types. In this respect, multipotent progenitor cells are also encompassed within the scope of the present invention. Multipotent progenitor cells are similar to mesenchymal stem cells as they have the ability to differentiate, in vitro, into cells with phenotypic characteristics of cells from all three germ cell layers (mesoderm, ectoderm and endoderm). Multipotent progenitor cells can be isolated in a fashion similar to mesenchymal stem cells, with adherence to plastic as an initial staple property; however additional separation techniques including magnetic activated cell sorting for CD45.sup.-/TER119.sup.- and 96-well single cell isolation/expansion on fibronectin in enriched media are required (Breyer, et al. (2006) Exp. Hematol. 34:1596-601). Multipotent progenitor cells possess certain cell surface markers (distinct from mesenchymal stem cells) including CD13, CD31 and SSEA-1 and lack markers including CD3, CD11b, CD19, CD34, CD44, CD45, MHC I and MHC II (Breyer et al. (2006) supra; Jiang, et al. (2002) Exp. Hematol. 34:809). Progenitor cells include satellite cells found in muscles; intermediate progenitor cells formed in the subventricular zone; bone marrow stromal cells; periosteum cells, which includes progenitor cells that develop into osteoblasts or chondroblasts; pancreatic progenitor cells; angioblasts or endothelial progenitor cells; and blast cells involved in the generation of B- and T-lymphocytes. In some embodiments, the invention includes the use of periosteum cells, osteoprogenitor cells or growth plate progenitor cells.

[0018] The invention applies to cells of an embryonic or adult origin in mammals, both human and non-human mammals, including but not limited to human and non-human primates, ungulates, ruminants and rodents. Ungulate species include, but are not limited to, cattle, sheep, goats, pigs, horses. Rodent species include, but are not limited to, rats and mice. The invention may also find application in other mammalian species such as rabbits, cats and dogs. Examples of preferred stem/progenitor cell populations which can be used in accordance with the methods of the present invention include primate stem/progenitor cells, such as human stem/progenitor cells. Such cells include adult human mesenchymal stem cells. As will be appreciated by one of skill in the art, a stem or progenitor cell referred to herein generally refers to a population of stem or progenitor cells.

[0019] Stem cells of the present invention can be isolated by conventional methods including Fluorescence Activated Cell Sorting (FACS), microbead separation, or affinity chromatograph using antibodies specific to cell surface antigens. Alternatively, stem cells can be isolated by enzymatic digestion of source tissue and gradient separation with, e.g., PERCOLL or HISTOPAQUE. Once isolated, the stem cells can be maintained and propagated in vitro under controlled conditions. Cells may be cultured in a variety of types of vessels constructed of, for example, glass or plastic. The surfaces of culture vessels may be pre-treated or coated with, for example, collagen, polylysine, or components of the extracellular matrix, to facilitate the cellular adherence. In addition, layers of adherent cells or feeder cells, which are used to support the growth of cells with more demanding growth requirements, may be used.

[0020] Cells are normally cultured under conditions designed to closely mimic those observed in vivo. In order to mimic the normal physiological environment, cells are generally incubated in a CO.sub.2 atmosphere with semi-synthetic growth media. Culture media is buffered and contains, among other things, amino acids, nucleotides, salts, vitamins, and also a supplement of serum such as fetal calf serum (FCS), horse serum or even human serum. Culture media may be further supplemented with growth factors and inhibitors such as hormones, transferrin, insulin, selenium, and attachment factors.

[0021] In certain aspects of the instant invention, cells are cultured prior to contact with a synthetic triterpenoid. They may also be cultured after contact, i.e., after they have been induced to express one or more of the genes disclosed herein or differentiate toward a given or specific phenotype. Cells will be cultured under specified conditions to achieve particular types of differentiation, and provided with various factors necessary to facilitate the desired differentiation.

[0022] In some embodiments, cells contacted with a synthetic triterpenoid are also contacted with one or more cell growth and differentiation factors. Cell growth and differentiation factors are molecules that stimulate cells to proliferate and/or promote differentiation of cell types into functionally mature forms. In some embodiments of the invention, cell growth and differentiation factors may be administered in combination with synthetic triterpenoids of the invention in order to direct the administered cells to proliferate and differentiate in a specific manner. One of ordinary skill would recognize that the various factors may be administered prior to, concurrently with, or subsequent to the administration of one or more synthetic triterpenoids of the present invention. In addition, administration of the growth and/or differentiation factors may be repeated as needed.

[0023] It is envisioned that a growth and/or differentiation factor may constitute a hormone, cytokine, hematapoietin, colony stimulating factor, interleukin, interferon, growth factor, other endocrine factor or combination thereof that act as intercellular mediators. Examples of such intercellular mediators are lymphokines, monokines, growth factors and traditional polypeptide hormones. Included among the growth factors are growth hormones such as human growth hormone, N-methionyl human growth hormone, and bovine growth hormone; parathyroid hormone; thyroxine; insulin; proinsulin; relaxin; prorelaxin; glycoprotein hormones such as follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), and luteinizing hormone (LH); hepatic growth factor; prostaglandin, fibroblast growth factor; prolactin; placental lactogen, OB protein; tumor necrosis factors -.alpha.and -.beta.; mullerian-inhibiting substance; mouse gonadotropin-associated peptide; inhibin; activin; vascular endothelial growth factor; integrin; thrombopoietin (TPO); nerve growth factors such as NGF-.beta.; platelet-growth factor; insulin-like growth factor-I and -II; erythropoietin (EPO); osteoinductive factors; interferons such as interferon.alpha., .beta., and -.gamma.; colony stimulating factors (CSFs) such as macrophage-CSF (M-CSF); granulocyte/macrophage-CSF (GM-CSF); and granulocyte-CSF (G-CSF); interleukins (ILs) such as IL-1, IL-1.alpha., IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-11, IL-12; IL-13, IL-14, IL-15, IL-16, IL-17, IL-18. As used herein, the term growth and/or differentiation factors include proteins from natural sources or from recombinant cell culture and biologically active equivalents of the native sequence, including synthetic molecules and mimetics.

[0024] The present disclosure provides methods of inducing the expression of one or more of SOX9, COL2A1, TGF-.beta.1, TGF-.beta.2, TGF-.beta.3, BMP2, BMP4, BMPRII, SMAD3, SMAD4, SMAD6, SMAD7, TIMP-1 or TIMP-2, such as in a stem/progenitor cell, and the prevention or treatment of disease. In some embodiments, the expression of one or more of SOX9, COL2A1, TGF-.beta.1, TGF-.beta.2, TGF-.beta.3, BMP2, BMP4, BMPRII, SMAD3, SMAD4, SMAD6, SMAD7, TIMP-1 or TIMP-2 in the stem/progenitor cell induces differentiation. For example, the results presented below demonstrate that CDDO-Imidazolide (CDDO-Im) and CDDO-Ethyl amide (CDDO-EA) induce expression of each of the above-reference genes and induce chondrogenesis in mesenchymal stem cells and organ cultures of newborn mouse calvaria. Accordingly, cells exposed to synthetic triterpenoids under in vitro, in vivo, or ex vivo conditions are of use in the treatment of diseases, conditions or disorders wherein altered gene expression has been shown to provide an advantage and/or transplantation of differentiated cells would provide a benefit. Examples of synthetic triterpenoid-mediated gene induction in particular stem cells and use of the same are as follows.

Synthetic Triterpenoid-Mediated Induction of SOX9

[0025] Sox9 is a member of the Sox gene family, which is characterized by the presence of an HMG box with more than 50% homology to the sex determining gene Sry (Schepers, et al. (2002) Dev. Cell 3:167-170). The HMG box can bind and bend DNA, and it has been proposed that Sox genes encode architectural DNA binding proteins. In addition to the HMG box, Sox9 possesses a transactivation domain at its C terminus (Sudbeck, et al. (1996) Nat. Genet. 13:230-232), and it has been shown that it can activate the genes Mis in testis (De Santa Barbara, et al. (1998) Mol. Cell Biol. 18:6653-6665; Arango, et al. (1999) Cell 99:409-419) and Col2aI (Bell, et al. (1997) Nat. Genet. 16:174-178) during chondrogenesis in vitro and in vivo. Moreover, in vitro studies suggest that Sox genes may also have a role in RNA splicing (Ohe, et al. (2002) Proc. Natl. Acad. Sci. USA 99:1146-51).

[0026] Degeneration of the intervertebral disc, often called "degenerative disc disease" (DDD) of the spine, is a condition that can be painful and can greatly affect the quality of one's life. While disc degeneration is a normal part of aging and for most people is not a problem, for certain individuals a degenerated disc can cause severe constant chronic pain. Etopic expression of Sox9 has been shown to induce adipose tissue-derived stem cells (ASCs) to function as real nucleus pulposus (NP) cells in vitro (Yang, et al. (2011) J. Orthop. Res. 29:1291-7). Sox-9-engineered ASCs (ASCs/Sox-9) were induced for the chondrocyte-like cell differentiation by 3D culture in alginate beads and TGF-.beta.3 for 2 weeks. After induction, type II collagen and proteoglycan levels significantly increased in the ASCs/Sox-9 compared to the ASCs. In addition, co-culture of induced ASCs/Sox-9 with matured NP cells resulted in enhanced increase in proteoglycan and type II collagen production (Yang, et al. (2011) supra). Therefore, synthetic triterpenoid-mediated induction of Sox9 in ACSs could be of use in differentiating ASCs into chondrocyte-like cells, which may be potentially used as a stem cell-based therapeutic tool for the treatment of degenerative disc diseases.

[0027] The chondrogenic effect of Sox9 on bone marrow mesenchymal stem cells (BMSCs) in vitro and its application in articular cartilage repair in vivo have been evaluated. Rabbit BMSCs were transduced with adenoviral vector containing Sox9. The results showed that Sox9 could induce chondrogenesis of BMSCs both in monolayer and on PGA scaffold effectively. A rabbit model with full-thickness cartilage defects was established and then repaired by PGA scaffold and rabbit BMSCs with or without Sox9 transduction. This analysis indicated that better repair, including more newly-formed cartilage tissue and hyaline cartilage-specific extracellular matrix and greater expression of several chondrogenesis marker genes were observed in PGA scaffold and BMSCs with Sox9 transduction, compared to that without transduction (Cao, et al. (2011) Biomaterials 32:3910-20). Therefore, synthetic triterpenoid-mediated induction of Sox9 in BMSCs could be of use in the repair of cartilage defects in vivo and in tissue engineering.

Synthetic Triterpenoid-Mediated Induction of BMP-2

[0028] BMP-2 can drive embryonic stem cells to the cartilage, osteoblast or adipogenic fate depending on supplementary co-factors (zur Nieden, et al. (2005) BMC Dev. Biol. 5:1). TGF-.beta.1, insulin and ascorbic acid have been identified as signals that together with BMP-2 induce a chondrocytic phenotype that is characterized by increased expression of cartilage marker genes in a timely co-ordinated fashion. BMP-2 induced chondrocytes undergo hypertrophy and begin to alter their expression profile towards osteoblasts. Supplying mineralization factors such as beta-glycerophosphate and vitamin D3 with the culture medium can facilitate this process. Moreover, gene expression studies show that adipocytes can also differentiate from BMP-2 treated ES cells. Ultimately, embryonic stem cells can be successfully triggered to differentiate into chondrocyte-like cells, which can further alter their fate to become hypertrophic, and adipocytes (zur Nieden, et al. (2005) supra). Therefore, this analysis and the results presented herein indicate that synthetic triterpenoid-mediated induction of BMP-2 in embryonic stem cells is of use as therapy in joint injury and disease.

[0029] Most spine fusion procedures involve the use of prosthetic fixation devices combined with autologous bone grafts rather than biological treatment. However, it has been shown that spine fusion can be achieved by injection of bone morphogenetic protein-2 (BMP-2)-expressing mesenchymal stem cells (MSCs) into the paraspinal muscle. BMP-2-expressing MSCs were injected bilaterally into paravertebral muscles of the mouse lumbar spine. Bone bridging of the targeted vertebrae was observed in the BMP-2-expressing MSC group, whereas no bone formation was noted in any control group. The biomechanical tests showed that MSC-mediated spinal fusion was as effective as stainless steel pin-based fusion and significantly more rigid than the control groups. (Sheyn, et al. (2010) Tissue Eng. Part A 16:3679-86). See also, Fu, et al. (2009) J. Orthop. Res. 27:380-4 and Hasharoni, et al. (2005) J. Neurosurg. Spine 3:47-52. These findings in combination with the results presented herein indicate that synthetic triterpenoid-mediated induction of BMP-2 in mesenchymal stem cells is of use in spinal fusion.

[0030] The regeneration of the periodontal attachment apparatus remains clinically challenging because of the involvement of three tissue types and the complexity of their relationship. It has been demonstrated that a combination of ex vivo autologous bone marrow MSCs engineered by replication-defective adenovirus to express the BMP-2 gene and Pluronic F127 (PF127) can be used to regenerate the periodontal attachment apparatus (Chen, et al. (2008) Gene Ther. 15:1469-77). Periodontal defects were surgically created in New Zealand white rabbits and treated with PF127 and MSCs expressing BMP-2. This approach regenerated not only cementum with Sharpey's fiber insertion, but also statistically significant quantities of bone, re-establishing a more normal relationship among the components of the regenerated periodontal attachment apparatus, which is beneficial for the maintenance of periodontal health (Chen, et al. (2008) supra). These findings in combination with the results presented herein indicate that synthetic triterpenoid-mediated induction of BMP-2 in mesenchymal stem cells, in combination with PF127, may represent an alternative means for periodontal alveolar bone graft in clinical settings.

[0031] Adult stem cells have therapeutic potential in bone regeneration. In this respect, it has been demonstrated that ex vivo modified MSC enhance bone density in an immunocompetent mouse model of osteopenia (Kumar, et al. (2010) Gene Ther. 17:105-16). MSC were transduced ex vivo with a recombinant adeno-associated virus 2 expressing BMP-2 under the transcriptional control of collagen type-1alpha promoter. The modified MSC were systemically administered to ovariectomized, female C57BL/6 mice. Results indicated that mice transplanted with MSC expressing BMP-2 showed significant increase in bone mineral density and bone mineral content with relatively better proliferative capabilities of bone marrow stromal cells and higher osteocompetent pool of cells compared to control animals. Micro-CT analysis of femora and other bone histomorphometric analyses indicated more trabecular bone following MSC-BMP-2 therapy. Moreover, production of BMP-2 from transplanted MSC also influenced the mobilization of endogenous progenitors for new bone formation (Kumar, et al. (2010) supra). Therefore, this analysis and the results presented herein indicate that synthetic triterpenoid-mediated induction of BMP-2 in mesenchymal stem cells is of use in increasing bone mineral density and content, and stimulating new bone formation in subjects with osteopenia.

Synthetic Triterpenoid-Mediated Induction of BMP-4

[0032] The potential of different growth factors (basic fibroblast growth factor (bFGF), TGF-.beta.1, activin-A, BMP-4, hepatocyte growth factor (HGF), epidermal growth factor (EGF), beta nerve growth factor (.beta.NGF), and retinoic acid) to direct the differentiation of human ES-derived cells in vitro has been analyzed (Schuldiner, et al. (2000) PNAS 97:11307-12). Differentiation of the cells was assayed by expression of 24 cell-specific molecular markers that cover all embryonic germ layers and 11 different tissues. Each growth factor had a unique effect that may have resulted from directed differentiation and/or cell selection, and could be divided into three categories: growth factors that mainly induce mesodermal cells (Activin-A and TGF-.beta.1); factors that activate ectodermal and mesodermal markers (retinoic acid, EGF, BMP-4, and bFGF); and factors that allow differentiation into the three embryonic germ layers, including endoderm (NGF and HGF) (Schuldiner, et al. (2000) supra). Therefore, synthetic triterpenoid-mediated induction of BMP-4 and/or TGF-.beta.1 in human ES cells may be of use in generating mesodermal cells and/or ectodermal cells.

Synthetic Triterpenoid-Mediated Induction of BMPRII

[0033] It is known that stem cells from exfoliated deciduous teeth (SHED) can be induced to differentiate into odontoblasts. SHED express the BMP receptors BMPRIA, BMPRIB, and BMPRII, and blockade of BMP-2 signaling inhibits the expression of markers of odontoblastic differentiation by SHED cultured in tooth slice/scaffolds. (Casagrande, et al. (2010) J. Dent. Res. 89:603-8). See also Yang, et al. (2007) Tissue Eng. 13:2803-12. Therefore, synthetic triterpenoid-mediated induction of BMPRII in SHED may be of use in combination with BMP-2 to facilitate differentiation into odontoblasts.

Synthetic Triterpenoid-Mediated Induction of TGF-.beta.2

[0034] Combinations of growth factors that induce effective chondrogenesis from adipose tissue-derived mesenchymal stem cells (ATMSCs) have been evaluated (Kim & Im (2009) Tissue Eng. Part A 15:1543-51). This analysis indicated that the combination of TGF-.beta.2 and BMP-7 most effectively induced chondrogenesis from ATMSCs (Kim & Im (2009) supra). Therefore, synthetic triterpenoid-mediated induction of TGF-.beta.2 in ATMSCs, in combination with BMP-7, can be used to enhance chondrogenesis of ATMSCs in cartilage tissue engineering.

Synthetic Triterpenoid-Mediated Induction of Smad4

[0035] The growth in height of the bone plate is a result of endochondral proliferation in epiphyseal growth plates and the conversion of chondrocytes into new bone. The control of chondrogenic differentiation and hypertrophy is critical for these processes. It has been demonstrated that treatment of ATDC5 cells with Genkwadaphnin induces cartilaginous nodules that are greater in number and larger in size than control cultures (Choi, et al. (2011) Eur. J. Pharmacol. 655:9-15). Genkwadaphnin increased the synthesis of matrix proteoglycans, induced the activation of alkaline phosphatase, as well as the expression of chondrogenic marker genes such as type II collagen, aggrecan, type I collagen, type X collagen, osteocalcin, and bone sialoprotein in ATDC5 cells. The expression of signaling molecules involved in chondrogenesis including Smad4, Sox9, and .beta.-catenin were also induced by treatment of ATDC5 cells with Genkwadaphnin. Furthermore, Genkwadaphnin induced the activation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK). To analyze the role of Genkwadaphnin in growth plate chondrocyte in vivo, mice were treated with Genkwadaphnin and chondrogenesis was analyzed. This analysis showed a significant expansion in growth plate and hypertrophic zone and numerous numbers of chondrocyte positive cells in hypertrophic and proliferative bone areas (Choi, et al. (2011) supra). Given these results and the results exemplified herein, synthetic triterpenoid-mediated induction of Smad4, Sox9, and type II collagen in cells of the growth plate may be of use in new therapeutic avenues to treat a variety of skeletal diseases, such as dwarfism.

[0036] As indicated herein, synthetic triterpenoids induce gene expression and stem/progenitor cell differentiation. In this respect, the present invention also provides a method for the treatment of a patient suffering from a degenerative disease or injury by transplantation into said patient of a population of stem/progenitor cells treated with a synthetic triterpenoid. Transplantation can be achieved using any conventional stem cell transplant procedure with or without a scaffold or matrix. In accordance with some embodiments, degenerative diseases or injuries that may be treated in accordance with this method of the invention, include but are not limited to, bone and cartilage injury, joint injury, dental disease, osteoarthritis, rheumatoid arthritis, degenerative disc disease, kyphosis, or osteopenia. In addition, the synthetic triterpenoids of the instant invention find application in the treatment of congenital disorders. In some embodiments, the congenital disorder is scoliosis or a skeletal disorder such as dwarfism. Embodiments of this method of the invention, therefore extend to the use of cells prepared according the present invention in the preparation of a medicament for the treatment of a degenerative disease, injury or congenital disorder.

[0037] Exemplary stem/progenitor cells, which can be treated with a synthetic triterpenoid, the result of treatment, and the therapeutic use of said cells are listed in Table 1.

TABLE-US-00001 TABLE 1 Result of Treatment with a Synthetic Stem/Progenitor Cell Triterpenoid Therapeutic Uses Adipose tissue- Induce chondrogenesis Cartilage tissue derived engineering mesenchymal Treatment of stem cells degenerative disc diseases Growth plate Bone formation Treatment of progenitors skeletal diseases Embryonic stem Induce chondrogenesis Treatment of joint cells injury and disease Mesenchymal Induce chondrogenesis Repair of stem cell cartilage defects Induce bone formation Spinal fusion Periodontal bone Periodontal formation alveolar bone graft in periodontal defects or disease Increase bone mineral Treatment of density and content Osteopenia Stem cells from Induce differentiation Treatment of exfoliated into odontoblasts dental caries deciduous teeth

[0038] For the purposes of the present invention, "prevention" or "preventing" includes inhibiting the onset of a disease in a subject or patient which may be at risk and/or predisposed to the disease but does not yet experience or display any or all of the pathology or symptomatology of the disease, and/or slowing the onset of the pathology or symptomatology of a disease in a subject or patient which may be at risk and/or predisposed to the disease but does not yet experience or display any or all of the pathology or symptomatology of the disease.

[0039] "Treatment" or "treating" includes inhibiting a disease in a subject or patient experiencing or displaying the pathology or symptomatology of the disease (e.g., arresting further development of the pathology and/or symptomatology), ameliorating a disease in a subject or patient that is experiencing or displaying the pathology or symptomatology of the disease (e.g., reversing the pathology and/or symptomatology), and/or effecting any measurable decrease in a disease in a subject or patient that is experiencing or displaying the pathology or symptomatology of the disease.

[0040] An "effective amount," "therapeutically effective amount" or "pharmaceutically effective amount" means that amount which, when administered to a subject or patient for treating a disease, is sufficient to effect such treatment for the disease.

[0041] Synthetic triterpenoids of use in the instant methods include synthetic oleanane triterpenoids. In particular embodiments, the synthetic triterpenoids of use in the instant methods have the structure of Formula I, which includes hydrates, isomers, prodrugs or pharmaceutically acceptable salts of Formula I:

##STR00001##

wherein, [0042] X.sup.1 and X.sup.2 are independently hydrogen, OR.sup.a, NR.sup.aR.sup.b, or SR.sup.a, wherein [0043] R.sup.a is a hydrogen, cyano, --CF.sub.3, nitro, amino, or substituted or unsubstituted heteroaryl group; [0044] R.sup.b is hydrogen, hydroxyl, alkyl, aryl, aralkyl, acyl, alkoxy, aryloxy, acyloxy, alkylamino, arylamino, amido, or a substituted version of any of these groups; [0045] or a substituent convertible in vivo to hydrogen; [0046] provided that R.sup.a is absent when the atom to which it is bound is part of a double bond, further provided that when R.sup.a is absent the atom to which it is bound is part of a double bond; [0047] Y is CH.sub.2 or CH.sub.2--CH.sub.2; [0048] Z is a covalent bond, --C(.dbd.O) alkanediyl, alkenediyl, alkynediyl, or a substituted version of any of these groups; [0049] the dashed bonds can be independently present or absent; [0050] R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently a hydrogen, hydroxyl, alkyl, substituted alkyl, alkoxy or substituted alkoxy group; [0051] R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9 and R.sup.10 are independently hydrogen, hydroxyl, halo, cyano, --C.ident.CR.sup.a, --CO.sub.2R.sup.a, --COR.sup.a, alkyl, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl, acyl, alkoxy, aryloxy, acyloxy, alkylamino, arylamino, nitro, amino, amido, --C(O)R.sup.c or a substituted version of any of these groups, wherein [0052] R.sup.c is hydrogen, hydroxy, halo, amino, hydroxyamino, azido or mercapto; or C.sub.1-C.sub.15-alkyl, C.sub.2-C.sub.15-alkenyl, C.sub.2-C.sub.15-alkynyl, C.sub.6-C.sub.15-aryl, C.sub.7-C.sub.15-aralkyl, C.sub.1-C.sub.15-heteroaryl, C.sub.2-C.sub.15-heteroaralkyl, C.sub.1-C.sub.15-acyl, C.sub.1-C.sub.15-alkoxy, C.sub.2-C.sub.15-alkenyloxy, C.sub.2-C.sub.15-alkynyloxy, C.sub.6-C.sub.15-aryloxy, C.sub.7-C.sub.15-aralkyloxy, C.sub.1-C.sub.15-heteroaryloxy, C.sub.2-C.sub.15-heteroaralkyloxy, C.sub.1-C.sub.15-acyloxy, C.sub.1-C.sub.15-alkylamino, C.sub.2-C.sub.15-dialkylamino, C.sub.1-C.sub.15-alkoxyamino, C.sub.2-C.sub.15-alkenylamino, C.sub.2-C.sub.15-alkynylamino, C.sub.6-C.sub.15-arylamino, C.sub.7-C.sub.15-aralkylamino, C.sub.1-C.sub.15-heteroarylamino, C.sub.2-C.sub.15-heteroaralkylamino, C.sub.1-C.sub.15-alkylsulfonylamino, C.sub.1-C.sub.15-amido, C.sub.1-C.sub.15-alkylsilyloxy, or substituted versions of any of these groups; or [0053] R.sup.5 and R.sup.6, R.sup.7 and R.sup.8, or R.sup.9 and R.sup.10 are independently taken together as .dbd.O; [0054] R.sup.11 and R.sup.12 are each independently hydrogen, hydroxyl, halo, alkyl , alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl, acyl, alkoxy, aryloxy, aralkoxy, heteroaryloxy, hetero-aralkoxy, acyloxy, alkylamino, dialkylamino, arylamino, aralkylamino, heteroarylamino, heteroaralkylamino, amido, or a substituted version of any of these groups, or [0055] R.sup.11 and R.sup.12 are taken together and are alkanediyl, alkenediyl, arenediyl, alkoxydiyl, alkenyloxydiyl, alkylaminodiyl, alkenylaminodiyl, or alkenylaminooxydiyl; [0056] R.sup.13 is hydrogen, hydroxy or oxo; [0057] R.sup.14 is hydrogen or hydroxyl; and [0058] R.sup.15 is [0059] a hydrogen, hydroxyl, --NR.sup.dR.sup.e, cyano, halo, azido, phosphate, 1,3-dioxoisoindolin-2-yl, mercapto, silyl or --COOH group, [0060] substituted or unsubstituted versions of C.sub.1-C.sub.15-alkyl, C.sub.2-C.sub.15-alkenyl, C.sub.2-C.sub.15-alkynyl, C.sub.6-C.sub.15-aryl, C.sub.7-C.sub.15-aralkyl, C.sub.1-C.sub.15-heteroaryl, C.sub.2-C.sub.15-heteroaralkyl,C.sub.1-C.sub.15acyl, C.sub.1-C.sub.15-alkoxy, C.sub.2-C.sub.15-alkenyloxy, C.sub.2-C.sub.15-alkynyloxy, C.sub.6-C.sub.15-aryloxy, C.sub.7-C.sub.15-aralkyloxy, C.sub.1-C.sub.15-heteroaryloxy, C.sub.2-C.sub.15-heteroaralkyloxy, C.sub.1-C.sub.15-acyloxy, C.sub.1-C.sub.15-alkylamino, C.sub.2-C.sub.15-alkenylamino, C.sub.2-C.sub.15-alkynylamino, C.sub.6-C.sub.15-arylamino, C.sub.7-C.sub.15-aralkylamino, C.sub.1-C.sub.15-heteroarylamino, C.sub.2-C.sub.15-heteroaralkylamino, C.sub.1-C.sub.15-amido, C.sub.2-C.sub.15-alkenylthio, C.sub.2-C.sub.15-alkynylthio, C.sub.2-C.sub.15- alkynylthio, C.sub.6-C.sub.15-arylthio, C.sub.7-C.sub.15-aralkylthio, C.sub.1-C.sub.15-heteroarylthio, C.sub.2-C.sub.15-heteroaralkylthio, C.sub.1-C.sub.15-acylthio, C.sub.1-C.sub.12-thioacyl, C.sub.1-C.sub.12-alkylsulfonyl, C.sub.2-C.sub.12-alkenylsulfonyl, C.sub.2-C.sub.12-alkynylsulfonyl, C.sub.6-C.sub.12-arylsulfonyl, C.sub.7-C.sub.12-aralkylsulfonyl, C.sub.1-C.sub.12-heteroarylsulfonyl, C.sub.1-C.sub.12-heteroaralkylsulfonyl, C.sub.1-C.sub.12-alkylsulfinyl, C.sub.2-C.sub.12-alkenylsulfinyl, C.sub.2-C.sub.12-alkynylsulfinyl, C.sub.6-C.sub.12-aryl sulfinyl, C.sub.7-C.sub.12-aralkylsulfinyl, C.sub.1-C.sub.12-heteroarylsulfinyl, C.sub.1-C.sub.12-heteroaralkylsulfinyl, C.sub.1-C.sub.12-alkylphosphonyl, C.sub.1-C.sub.12-alkylphosphate, C.sub.2-C.sub.12-dialkylphosphate, C.sub.1-C.sub.12-alkylammonium, C.sub.1-C.sub.12-alkylsulfonium, C.sub.1-C.sub.15-alkylsilyl, or a substituted version of any of these groups, [0061] a --CO.sub.2Me, carbonyl imidazole, --CO--D-Glu(OAc).sub.4, --CONH.sub.2, --CONHNH.sub.2, --CONHCH.sub.2CF.sub.3, or --C(=O)-heteroaryl group, or [0062] Z and R.sup.15 form a three to seven-membered ring, such that Z and R.sup.15 are further connected to one another through one or more of --O--and alkanediyl, further wherein Z is --CH-- and R.sup.15 is --CH.sub.2-- or Z, R.sup.15, and carbon numbers 13, 17 and 18 form a ring such that R.sup.15 is bound to carbon 13, wherein Y is methanediyl or substituted methanediyl and R.sup.15 is --O--, wherein [0063] R.sup.d and R.sup.e are independently hydrogen, hydroxyl, alkyl, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl, acyl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, aralkoxy, heteroaryloxy, heteroaralkoxy, thioacyl, alkylsulfonyl, alkenylsulfonyl, alkynylsulfonyl, arylsulfonyl, aralkylsulfonyl, heteroarylsulfonyl, or heteroaralkylsulfonyl, or a substituted version of any of these groups.

[0064] In certain embodiments, the bond between C.sub.2 and C.sub.3 in the A-ring is a double bond. In other embodiments, the bond between C.sub.2 and C.sub.3 in the A-ring is a single bond.

[0065] Exemplary compounds of use in the methods of the present invention include CDDO, CDDO-Me, CDDO-MA, CDDO-TFEA, CDDO-EA, CDDO-Im and compound 1.

##STR00002## ##STR00003##

[0066] As used herein, "hydrogen" means --H; "hydroxyl" means --OH; "oxo" means .dbd.O; "halo" or "halogen" means independently --F, --Cl, --Br or --I; "hydroxyamino" means --NHOH; "nitro" means --NO.sub.2; "cyano" means --CN; "azido" means --N.sub.3; "mercapto" means --SH; "thio" means .dbd.S; "sulfonyl" means --S(O).sub.2-- (see additional definitions of groups containing the term sulfonyl, e.g., alkylsulfonyl); and "silyl" means --SiH.sub.3 (see additional definitions of group(s) containing the term silyl, e.g., alkylsilyl).

[0067] For the groups below, the following parenthetical subscripts further define the groups as follows: "(Cn)" defines the exact number (n) of carbon atoms in the group. For example, "C.sub.1-C.sub.15-alkoxy" designates those alkoxy groups having from 1 to 15 carbon atoms (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. or any range derivable therein (e.g., 3-10 carbon atoms)).

[0068] The term "alkyl" refers to a non-aromatic monovalent group with a saturated carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and no atoms other than carbon and hydrogen. The groups, --CH.sub.3, --CH.sub.2CH.sub.3, --CH.sub.2CH.sub.2CH.sub.3, --CH(CH.sub.3).sub.2, --CH(CH.sub.2).sub.2, --CH.sub.2CH.sub.2CH.sub.2CH.sub.3, --CH(CH.sub.3)CH.sub.2CH.sub.3, ---CH.sub.2CH(CH.sub.3).sub.2, --C(CH.sub.3).sub.3, --CH.sub.2C(CH.sub.3).sub.3, cyclobutyl, cyclopentyl, cyclohexyl, and cyclohexylmethyl are non-limiting examples of alkyl groups.

[0069] The term "alkanediyl" refers to a non-aromatic divalent group, wherein the alkanediyl group is attached with two .sigma.-bonds, with one or two saturated carbon atom(s) as the point(s) of attachment, a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds, and no atoms other than carbon and hydrogen. The groups, --CH.sub.2-- (methylene), --CH.sub.2CH.sub.2--, --CH.sub.2C(CH.sub.3).sub.2CH.sub.2--, and --CH.sub.2CH.sub.2CH.sub.2-- are non-limiting examples of alkanediyl groups.

[0070] The term "alkenyl" refers to a monovalent group with a nonaromatic carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one nonaromatic carbon-carbon double bond, no carbon-carbon triple bonds, and no atoms other than carbon and hydrogen. Non-limiting examples of alkenyl groups include: --CH.dbd.CH.sub.2, --CH.dbd.CHCH.sub.3, --CH.dbd.CHCH.sub.2CH.sub.3, --CH.sub.2CH.dbd.CH.sub.2, --CH.sub.2CH.dbd.CHCH.sub.3, and --CH.dbd.CH--C.sub.6H.sub.5.

[0071] The term "alkenediyl" refers to a nonaromatic divalent group, wherein the alkenediyl group is attached with two .sigma.-bonds, with two carbon atoms as points of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one nonaromatic carbon-carbon double bond, no carbon-carbon triple bonds, and no atoms other than carbon and hydrogen. The groups, --CH.dbd.CH--, --CH.dbd.C(CH.sub.3)CH.sub.2--, and --CH.dbd.CHCH.sub.2-- are non-limiting examples of alkenediyl groups.

[0072] The term "alkynyl" refers to a monovalent group with a nonaromatic carbon atom as the point of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon triple bond, and no atoms other than carbon and hydrogen. The groups, --C.ident.CH, --C.ident.CCH.sub.3, --C.ident.CC.sub.6H.sub.5 and --CH.sub.2C.ident.CCH.sub.3, are non-limiting examples of alkynyl groups.

[0073] The term "alkynediyl" refers to a nonaromatic divalent group, wherein the alkynediyl group is attached with two .sigma.-bonds, with two carbon atoms as points of attachment, a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon triple bond, and no atoms other than carbon and hydrogen. The groups, --C.ident.C--, --C.ident.CCH.sub.2--, and --C.ident.CCH(CH.sub.3)-- are non-limiting examples of alkynediyl groups.

[0074] The term "aryl" refers to a monovalent group with an aromatic carbon atom as the point of attachment, said carbon atom forming part of a six-membered aromatic ring structure wherein the ring atoms are all carbon, and wherein the monovalent group is composed of carbon and hydrogen. Non-limiting examples of aryl groups include phenyl, methylphenyl, (dimethyl)phenyl, -ethylphenyl, propylphenyl, --C.sub.6H.sub.4CH(CH.sub.3).sub.2, --C.sub.6H.sub.4CH(CH.sub.2).sub.2, methylethylphenyl, vinylphenyl, naphthyl, and the monovalent group derived from biphenyl.

[0075] The term "arenediyl" refers to a divalent group, wherein the arenediyl group is attached with two .sigma.-bonds, with two aromatic carbon atoms as points of attachment, said carbon atoms forming part of one or more six-membered aromatic ring structure(s) wherein the ring atoms are all carbon, and wherein the monovalent group is composed of carbon and hydrogen. Non-limiting examples of arenediyl groups include:

##STR00004##

[0076] The term "aralkyl" refers to the monovalent group--alkanediyl-aryl, in which the terms alkanediyl and aryl are each used in a manner consistent with the definitions provided above. Non-limiting examples of aralkyls include 1-phenyl-ethyl, 2-phenyl-ethyl, indenyl and 2,3-dihydro-indenyl, provided that indenyl and 2,3-dihydro-indenyl are only examples of aralkyl in so far as the point of attachment in each case is one of the saturated carbon atoms.

[0077] The term "heteroaryl" refers to a monovalent group with an aromatic carbon atom or nitrogen atom as the point of attachment, said carbon atom or nitrogen atom forming part of an aromatic ring structure wherein at least one of the ring atoms is nitrogen, oxygen or sulfur, and wherein the monovalent group is composed of carbon, hydrogen, aromatic nitrogen, aromatic oxygen or aromatic sulfur. Non-limiting examples of aryl groups include acridinyl, furanyl, imidazoimidazolyl, imidazopyrazolyl, imidazopyridinyl, imidazopyrimidinyl, indolyl, indazolinyl, methylpyridyl, oxazolyl, phenylimidazolyl, pyridyl, pyrrolyl, pyrimidyl, pyrazinyl, quinolyl, quinazolyl, quinoxalinyl, tetrahydroquinolinyl, thienyl, triazinyl, pyrrolopyridinyl, pyrrolopyrimidinyl, pyrrolopyrazinyl, pyrrolotriazinyl, pyrroloimidazolyl, chromenyl (where the point of attachment is one of the aromatic atoms), and chromanyl (where the point of attachment is one of the aromatic atoms).

[0078] The term "heteroaralkyl" refers to the monovalent group -alkanediyl-heteroaryl, in which the terms alkanediyl and heteroaryl are each used in a manner consistent with the definitions provided above. Non-limiting examples of aralkyls include pyridylmethyl, and thienylmethyl.

[0079] The term "acyl" refers to a monovalent group with a carbon atom of a carbonyl group as the point of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure. The groups, --CHO, --C(.dbd.O)CH.sub.3, --C(.dbd.O)CH.sub.2CH.sub.3, --C(.dbd.O)CH.sub.2CH.sub.2CH.sub.3, --C(.dbd.O)CH(CH.sub.3).sub.2, --C(.dbd.O)CH(CH.sub.2).sub.2, --C(.dbd.O)C.sub.6H.sub.5, --C(.dbd.O)C.sub.6H.sub.4CH.sub.3, and --C(.dbd.O)C.sub.6H.sub.4CH.sub.2CH.sub.3 are non-limiting examples of acyl groups. The term "acyl" therefore encompasses, but is not limited to groups sometimes referred to as "alkyl carbonyl" and "aryl carbonyl" groups.

[0080] The term "alkoxy" refers to the group --OR, in which R is an alkyl, as that term is defined herein. Non-limiting examples of alkoxy groups include --OCH.sub.3, --OCH.sub.2CH.sub.3, --OCH.sub.2CH.sub.2CH.sub.3, --OCH(CH.sub.3).sub.2, --OCH(CH.sub.2).sub.2, --O-cyclopentyl, and --O-cyclohexyl.

[0081] Similarly, the terms "alkenyloxy," "alkynyloxy," "aryloxy," "aralkoxy," "heteroaryloxy," "heteroaralkoxy" and "acyloxy," refer to groups, defined as --OR, in which R is alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and acyl, respectively, as those terms are defined above.

[0082] The term "alkoxydiyl" refers to a non-aromatic divalent group, wherein the alkoxydiyl group is attached with two .sigma.-bonds, with (a) two saturated carbon atoms as points of attachment, (b) one saturated carbon atom and one oxygen atom as points of attachment, or (c) two oxygen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, no carbon-carbon double or triple bonds in the group's backbone, further having no backbone atoms other than carbon or oxygen and having at least one of each of these atoms in the group's backbone. The groups, --O--CH.sub.2CH.sub.2--, --CH.sub.2--O--CH.sub.2CH.sub.2--, --O--CH.sub.2CH.sub.2--O-- and --O--CH.sub.2--O-- are non-limiting examples of alkoxydiyl groups.

[0083] The term "alkenyloxydiyl" refers to a divalent group that is nonaromatic prior to attachment, wherein the alkenyloxydiyl group is attached with two .sigma.-bonds, which may become aromatic upon attachment, with (a) two carbon atoms as points of attachment, (b) one carbon atom and one oxygen atom as points of attachment, or (c) two oxygen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon double bond that is non-aromatic at least prior to attachment, further having no backbone atoms other than carbon or oxygen and having at least one of each of these atoms in the group's backbone. The groups, --O--CH.dbd.CH--, --O--CH.dbd.CHO-- and --O--CH.dbd.CHCH.sub.2-- are non-limiting examples of alkenyloxydiyl groups.

[0084] The term "amino" refers to a moiety of the formula --NRR', wherein R and R' are independently hydrogen, alkyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl.

[0085] The term "alkylamino" refers to the group --NHR, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylamino groups include --NHCH.sub.3, --NHCH.sub.2CH.sub.3, --NHCH.sub.2CH.sub.2CH.sub.3, --NHCH(CH.sub.3).sub.2, --NHCH(CH.sub.2).sub.2, --NHCH.sub.2CH.sub.2CH.sub.2CH.sub.3, --NHCH(CH.sub.3)CH.sub.2CH.sub.3, --NHCH.sub.2CH(CH.sub.3).sub.2, --NHC (CH.sub.3).sub.3, --NH-cyclopentyl, and --NH-cyclohexyl.

[0086] Similarly, the terms "alkoxyamino," "alkenylamino," "alkynylamino," "arylamino," "aralkylamino," "heteroarylamino," "heteroaralkylamino," and "alkylsulfonylamino" refer to groups, defined as --NHR, in which R is alkoxy, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and alkylsulfonyl, respectively, as those terms are defined above. A non-limiting example of an arylamino group is --NHC.sub.6H.sub.5.

[0087] The term "dialkylamino" refers to the group --NRR', in which R and R' can be the same or different alkyl groups, or R and R' can be taken together to represent an alkanediyl having two or more saturated carbon atoms, at least two of which are attached to the nitrogen atom. Non-limiting examples of dialkylamino groups include --NHC(CH.sub.3).sub.3, --N(CH.sub.3)CH.sub.2CH.sub.3, --N(CH.sub.2CH.sub.3).sub.2, N-pyrrolidinyl, and N-piperidinyl.

[0088] The term "alkylaminodiyl" refers to a non-aromatic divalent group, wherein the alkylaminodiyl group is attached with two .sigma.-bonds, with (a) two saturated carbon atoms as points of attachment, (b) one saturated carbon atom and one nitrogen atom as points of attachment, or (c) two nitrogen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, no double or triple bonds in the group's backbone, further having no backbone atoms other than carbon or nitrogen and having at least one of each of these atoms in the group's backbone. The groups, --NH--CH.sub.2CH.sub.2--, --CH.sub.2--NH--CH.sub.2CH.sub.2--, --NH--CH.sub.2CH.sub.2--NH-- and --NH--CH.sub.2--NH-- are non-limiting examples of alkylaminodiyl groups.

[0089] The term "alkenylaminodiyl" refers to a divalent group that is nonaromatic prior to attachment, wherein the alkenylaminodiyl group is attached with two .sigma.-bonds, which may become aromatic upon attachment, with (a) two carbon atoms as points of attachment, (b) one carbon atom and one nitrogen atom as points of attachment, or (c) two nitrogen atoms as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon double bond or carbon-nitrogen double that is non-aromatic at least prior to attachment, further having no backbone atoms other than carbon or nitrogen. The groups --NH--CH.dbd.CH--, --NH--CH.dbd.N-- and --NH--CH.dbd.CH--NH-- are non-limiting examples of alkenylaminodiyl groups.

[0090] The term "alkenylaminooxydiyl" refers to a divalent group, wherein the alkenylaminooxydiyl group is attached with two .sigma.-bonds, which may become aromatic upon attachment, with two atoms selected from the group consisting of carbon, oxygen and nitrogen as points of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure, at least one carbon-carbon double bond, carbon-nitrogen double, or nitrogen-nitrogen double bond that is non-aromatic at least prior to attachment, further having no backbone atoms other than carbon nitrogen or oxygen and having at least one of each of these three atoms in the backbone. The group --O--CH.dbd.N--, is a non-limiting example of an alkenylaminooxydiyl group.

[0091] The term "amido" (acylamino) refers to the group --NHR, in which R is acyl, as that term is defined herein. A non-limiting example of an acylamino group is --NHC(.dbd.O)CH.sub.3.

[0092] The term "alkylthio" refers to the group --SR, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylthio groups include ---SCH.sub.3, --SCH.sub.2CH.sub.3, --SCH.sub.2CH.sub.2CH.sub.3, --SCH(CH.sub.3).sub.2, --SCH(CH.sub.2).sub.2, --S-cyclopentyl, and --S-cyclohexyl.

[0093] Similarly, the terms "alkenylthio," "alkynylthio," "arylthio," "aralkylthio," "heteroarylthio," "heteroaralkylthio" and "acylthio" refer to groups, defined as --SR, in which R is alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl and acyl, respectively, as those terms are defined above.

[0094] The term "thioacyl" refers to a monovalent group with a carbon atom of a thiocarbonyl group as the point of attachment, further having a linear or branched, cyclo, cyclic or acyclic structure. The groups --CHS, --C(.dbd.S)CH.sub.3, --C(.dbd.S)CH.sub.2CH.sub.3, --C(.dbd.S)CH.sub.2CH.sub.2CH.sub.3, --C(.dbd.S)CH(CH.sub.3).sub.2, --C(.dbd.S)CH(CH.sub.2).sub.2, --C(.dbd.S)C.sub.6H.sub.5, --(.dbd.S)C.sub.6H.sub.4CH.sub.3, --C(.dbd.S)C.sub.6H.sub.4CH.sub.2CH.sub.3, C(.dbd.S)C.sub.6H.sub.3(CH.sub.3).sub.2, and --C(.dbd.S)CH.sub.2C.sub.6Hs, are non-limiting examples of thioacyl groups. The term "thioacyl" therefore encompasses, but is not limited to, groups sometimes referred to as "alkyl thiocarbonyl" and "aryl thiocarbonyl" groups.

[0095] The term "alkylsulfonyl" refers to the group --S(.dbd.O).sub.2R, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylsulfonyl groups include: --S(.dbd.O).sub.2CH.sub.3, --S(.dbd.O).sub.2CH.sub.2CH.sub.3, --S(.dbd.O).sub.2CH.sub.2CH.sub.2CH.sub.3, --S(.dbd.O).sub.2CH(CH.sub.3).sub.2, --S(.dbd.O).sub.2CH(CH.sub.2).sub.2, --S(.dbd.O).sub.2-cyclopentyl, and --S(.dbd.O).sub.2-cyclohexyl.

[0096] Similarly, the terms "alkenylsulfonyl," "alkynylsulfonyl," "arylsulfonyl," "aralkylsulfonyl," "heteroarylsulfonyl," and "heteroaralkylsulfonyl" refer to groups, defined as --S(O).sub.2R, in which R is alkenyl, alkynyl, aryl, aralkyl, heteroaryl, and heteroaralkyl, respectively, as those terms are defined above.

[0097] The term "alkylsulfinyl" refers to the group --S(.dbd.O)R, in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylsulfinyl groups include --S(.dbd.O)CH.sub.3, --S(.dbd.O)CH.sub.2CH.sub.3, --S(.dbd.O)CH.sub.2CH.sub.2CH.sub.3, --S(.dbd.O)CH(CH.sub.3).sub.2, --S(.dbd.O)CH(CH.sub.2).sub.2, --S(.dbd.O)-cyclopentyl, and --S(.dbd.O)-cyclohexyl.

[0098] Similarly, the terms "alkenylsulfinyl," "alkynylsulfinyl," "arylsulfinyl," "aralkylsulfinyl," "heteroarylsulfinyl" and "heteroaralkylsulfinyl" refer to groups, defined as --S(.dbd.O)R, in which R is alkenyl, alkynyl, aryl, aralkyl, heteroaryl, and heteroaralkyl, respectively, as those terms are defined above.

[0099] The term "alkylammonium" refers to a group, defined as --NH.sub.2R.sup.+, --NHRR'.sup.+, or --NRR'R''.sup.+, in which R, R' and R'' are the same or different alkyl groups, or any combination of two of R, R' and R'' can be taken together to represent an alkanediyl. Non-limiting examples of alkylammonium cation groups include --NH.sub.2(CH.sub.3).sup.+, --NH.sub.2(CH.sub.2CH.sub.3)+, --NH.sub.2(CH.sub.2CH.sub.2CH.sub.3)+, --NH(CH.sub.3).sub.2.sup.+, --NH(CH.sub.2CH.sub.3).sub.2.sup.+, --NH(CH.sub.2CH.sub.2CH.sub.3).sub.2.sup.+, --N (CH.sub.3).sub.3.sup.+, --N(CH.sub.3)(CH.sub.2CH.sub.3).sub.2.sup.+, --N(CH.sub.3).sub.2(CH.sub.2CH.sub.3).sup.+, --N.sub.2C(CH.sub.3).sub.3.sup.+, --NH(cyclopentyl).sub.2.sup.+, and --NH.sub.2(cyclohexyl).sup.30.

[0100] The term "alkylsulfonium" refers to the group --SRR', in which R and R' can be the same or different alkyl groups, or R and R' can be taken together to represent an alkanediyl. Non-limiting examples of alkylsulfonium groups include --SH(CH.sub.3), --SH(CH.sub.2CH.sub.3), --SH(CH.sub.2CH.sub.2CH.sub.3), --S(CH.sub.3).sub.2, --S(CH.sub.2CH.sub.3).sub.2, (CH.sub.2CH.sub.2CH.sub.3).sub.2, --SH(cyclopentyl), and --SH(cyclohexyl).

[0101] The term "alkylsilyl" refers to a monovalent group, defined as --SiH.sub.2R, --SiHRR', or --SiRR'R'', in which R, R' and R'' can be the same or different alkyl groups, or any combination of two of R, R' and R'' can be taken together to represent an alkanediyl. The groups --SiH.sub.2CH.sub.3, --SiH(CH.sub.3).sub.2, --Si(CH.sub.3).sub.3 and --Si(CH.sub.3).sub.2C(CH.sub.3).sub.3, are non-limiting examples of unsubstituted alkylsilyl groups.

[0102] The term "alkylphosphonyl" refers to the group --OPO(OR).sub.2, where R is alkyl, as defined herein.

[0103] The term "alkylphosphate" refers to the group --OP(.dbd.O)(OH)(OR), in which R is an alkyl, as that term is defined above. Non-limiting examples of alkylphosphate groups include --OP(.dbd.O)(OH)(OMe) and --OP(.dbd.O)(OH)(OEt).

[0104] The term "dialkylphosphate" refers to the group --OP(.dbd.O)(OR)(OR'), in which R and R' can be the same or different alkyl groups, or R and R' can be taken together to represent an alkanediyl having two or more saturated carbon atoms, at least two of which are attached via the oxygen atoms to the phosphorus atom. Non-limiting examples of dialkylphosphate groups include --OP(.dbd.O)(OMe).sub.2, --OP(.dbd.O)(OEt)(OMe) and --OP(.dbd.O)(OEt).sub.2.

[0105] "Cycloalkyl" means a non-aromatic mono- or multicyclic ring system including about 3 to about 10 carbon atoms, preferably about 5 to about 10 carbon atoms. Non-limiting examples of suitable monocyclic cycloalkyls include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl and the like. Non-limiting examples of suitable multicyclic cycloalkyls include 1-decalinyl, norbornyl, adamantyl and the like.

[0106] "Heterocyclyl" or "heterocycloalkyl" means a non-aromatic saturated monocyclic or multicyclic ring system including about 3 to about 10 ring atoms, preferably about 5 to about 10 ring atoms, in which one or more of the atoms in the ring system is an element other than carbon, for example nitrogen, oxygen or sulfur, alone or in combination. Preferred heterocyclyls contain about 5 to about 6 ring atoms. The prefix aza, oxa or thia before the heterocyclyl root name means that at least a nitrogen, oxygen or sulfur atom respectively is present as a ring atom. The nitrogen or sulfur atom of the heterocyclyl can be optionally oxidized to the corresponding N-oxide, S-oxide or S,S-dioxide. Non-limiting examples of suitable monocyclic heterocyclyl rings include piperidyl, pyrrolidinyl, piperazinyl, morpholinyl, thiomorpholinyl, thiazolidinyl, 1,4-dioxanyl, tetrahydrofuranyl, tetrahydrothiophenyl, lactam, lactone, and the like. Non-limiting examples of suitable bicyclic heterocyclyl rings include decahydro-isoquinoline, decahydro-[2,6]naphthyridine, and the like.

[0107] Any of the groups described herein may be unsubstituted or optionally substituted. When modifying a particular group, "substituted" means that the group the term modifies may, but does not have to, be substituted. Substitutions typically replace an available hydrogen with an alkyl, alkenyl, alkynyl, aryl, heteroaryl, aralkyl, alkylaryl, heteroaralkyl, heteroarylalkenyl, heteroarylalkynyl, alkylheteroaryl, hydroxy, hydroxyalkyl, alkoxy, aryloxy, aralkoxy, alkoxyalkoxy, acyl, halo, nitro, cyano, carboxy, alkoxycarbonyl, aryloxycarbonyl, aralkoxycarbonyl, alkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, alkylthio, arylthio, heteroarylthio, aralkylthio, heteroaralkylthio, cycloalkyl, or heterocyclyl.

[0108] Any undefined valency on an atom of a structure shown in this application implicitly represents a hydrogen atom bonded to the atom.

[0109] The term "hydrate" when used as a modifier to a compound means that the compound has less than one (e.g., hemihydrate), one (e.g., monohydrate), or more than one (e.g., dihydrate) water molecules associated with each compound molecule, such as in solid forms of the compound.

[0110] An "isomer" of a first compound is a separate compound in which each molecule contains the same constituent atoms as the first compound, but where the configuration of those atoms in three dimensions differs.

[0111] "Pharmaceutically acceptable salts" means salts of compounds of the present invention which are pharmaceutically acceptable, and which possess the desired pharmacological activity. Such salts include acid addition salts formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or with organic acids such as 1,2-ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, 2-naphthalenesulfonic acid, 3-phenylpropionic acid, 4,4'-methylenebis(3-hydroxy-2-ene-1-carboxylic acid), 4-methylbicyclo[2.2.2]oct-2-ene-1-carboxylic acid, acetic acid, aliphatic mono- and di-carboxylic acids, aliphatic sulfuric acids, aromatic sulfuric acids, benzenesulfonic acid, benzoic acid, camphorsulfonic acid, carbonic acid, cinnamic acid, citric acid, cyclopentanepropionic acid, ethanesulfonic acid, fumaric acid, glucoheptonic acid, gluconic acid, glutamic acid, glycolic acid, heptanoic acid, hexanoic acid, hydroxynaphthoic acid, lactic acid, laurylsulfuric acid, maleic acid, malic acid, malonic acid, mandelic acid, methanesulfonic acid, muconic acid, o-(4-hydroxybenzoyl)benzoic acid, oxalic acid, p-chlorobenzenesulfonic acid, phenyl-substituted alkanoic acids, propionic acid, p-toluenesulfonic acid, pyruvic acid, salicylic acid, stearic acid, succinic acid, tartaric acid, tertiarybutylacetic acid, trimethylacetic acid, and the like. Pharmaceutically acceptable salts also include base addition salts which may be formed when acidic protons present are capable of reacting with inorganic or organic bases. Acceptable inorganic bases include sodium hydroxide, sodium carbonate, potassium hydroxide, aluminum hydroxide and calcium hydroxide. Acceptable organic bases include ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine and the like. It should be recognized that the particular anion or cation forming a part of any salt of this invention is not critical, so long as the salt, as a whole, is pharmacologically acceptable. Additional examples of pharmaceutically acceptable salts and their methods of preparation and use are presented in Handbook of Pharmaceutical Salts: Properties, and Use (P. H. Stahl & C. G. Wermuth eds., Verlag Helvetica Chimica Acta, 2002).

[0112] Compounds of the invention may also exist in prodrug form. Since prodrugs are known to enhance numerous desirable qualities of pharmaceuticals, e.g., solubility, bioavailability, manufacturing, etc., the compounds employed in some methods of the invention may, if desired, be delivered in prodrug form. Thus, the invention contemplates prodrugs of compounds of the present invention as well as methods of delivering prodrugs. Prodrugs of the compounds employed in the invention may be prepared by modifying functional groups present in the compound in such a way that the modifications are cleaved, either in routine manipulation or in vivo, to the parent compound. Accordingly, prodrugs include, for example, compounds described herein in which a hydroxy, amino, or carboxy group is bonded to any group that, when the prodrug is administered to a patient, cleaves to form a hydroxy, amino, or carboxylic acid, respectively. For example, a compound comprising a hydroxy group may be administered as an ester that is converted by hydrolysis in vivo to the hydroxy compound. Suitable esters that may be converted in vivo into hydroxy compounds include acetates, citrates, lactates, phosphates, tartrates, malonates, oxalates, salicylates, propionates, succinates, fumarates, maleates, methylene-bis-.beta.-hydroxynaphthoate, gentisates, isethionates, di-p-toluoyltartrates, methanesulfonates, ethanesulfonates, benzenesulfonates, p-toluenesulfonates, cyclohexylsulfamates, quinates, esters of amino acids, and the like. Similarly, a compound comprising an amine group may be administered as an amide that is converted by hydrolysis in vivo to the amine compound.

[0113] The synthetic triterpenoids of the present disclosure may be provided to a stem/progenitor cell ex vivo, in vitro or in vivo. When used under ex vivo or in vivo conditions, the stem/progenitor cell may be cultured under conventional cell culture conditions in the presence of a synthetic triterpenoid to induce the expression of one or more the genes described herein. As described herein, additional cell growth and differentiation factors may be employed to facilitate differentiation of the stem/progenitor cells. Stem/progenitor cells treated in such a manner can then be transplanted into a subject for therapeutic purposes.

[0114] The present invention also extends to articles coated with one or more synthetic triterpenoids, such as tissue culture dishes, multi-well plates (e.g., 1, 2, 4, 8, 24, 48, 96-wells, etc), PETRI-dishes, tissue culture flasks, fermentors, bioreactors, etc. for differentiating stem/progenitor cells. Such articles may be composed of any generally suitable material, such as a plastics material, for example polypropylene, or other materials such as glass, metal, etc. Suitable metals include mirror-polished metals, e.g., mirror-polished stainless steel.

[0115] When used in vivo, i.e., administered directly to a subject, the instant synthetic triterpenoids can be administered by a variety of methods, e.g., orally or by injection (e.g. subcutaneous, intravenous, intraperitoneal, etc.). Depending on the route of administration, the active compounds may be coated in a material to protect the compound from the action of acids and other natural conditions which may inactivate the compound. They may also be administered by continuous perfusion/infusion into a subject or wound site.

[0116] To administer the therapeutic compound by other than parenteral administration, it may be necessary to coat the compound with, or co-administer the compound with, a material to prevent its inactivation. For example, the therapeutic compound may be administered to a patient in an appropriate carrier, for example, liposomes, or a diluent. Pharmaceutically acceptable diluents include saline and aqueous buffer solutions. Liposomes include water-in-oil-in-water CGF emulsions as well as conventional liposomes (Strejan, et al. (1984) J. Neuroimmunol. 7:27).

[0117] The therapeutic compound may also be administered parenterally, intraperitoneally, intraspinally, or intracerebrally. Dispersions can be prepared in glycerol, liquid polyethylene glycols, and mixtures thereof and in oils. Under ordinary conditions of storage and use, these preparations may contain a preservative to prevent the growth of microorganisms.

[0118] Sterile injectable solutions can be prepared by incorporating the synthetic triterpenoid in the required amount in an appropriate solvent with one or a combination of ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the synthetic triterpenoid into a sterile carrier which contains a basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and freeze-drying which yields a powder of the active ingredient (i.e., the synthetic triterpenoid) plus any additional desired ingredient from a previously sterile-filtered solution thereof.

[0119] The synthetic triterpenoid can be orally administered, for example, with an inert diluent or an assimilable edible carrier. The synthetic triterpenoid and other ingredients may also be enclosed in a hard or soft shell gelatin capsule, compressed into tablets, or incorporated directly into the patient's diet. For oral therapeutic administration, the synthetic triterpenoid may be incorporated with excipients and used in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. The percentage of the synthetic triterpenoid in the compositions and preparations may, of course, be varied. The amount of the synthetic triterpenoid in such therapeutically useful compositions is such that a suitable dosage will be obtained.

[0120] It is especially advantageous to formulate parenteral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used herein refers to physically discrete units suited as unitary dosages for the patients to be treated; each unit containing a predetermined quantity of synthetic triterpenoid calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the invention are dictated by and directly dependent on (a) the unique characteristics of the synthetic triterpenoid and the particular therapeutic effect to be achieved, and (b) the limitations inherent in the art of compounding such a synthetic triterpenoid for the treatment of a selected condition in a patient.

[0121] The synthetic triterpenoid may also be administered topically to the skin, eye, or mucosa. Alternatively, if local delivery to the lungs is desired the synthetic triterpenoid may be administered by inhalation in a dry-powder or aerosol formulation.

[0122] In yet another embodiment, the synthetic triterpenoid can be administered as a coating on an article for implantation. Such articles include polymer scaffolds containing stem/progenitor cells, stents, shunts, and the like.

[0123] Active compounds are administered at a therapeutically effective dosage sufficient to treat a condition associated with a given patient. For example, the efficacy of a synthetic triterpenoid can be evaluated in an animal model system that may be predictive of efficacy in treating the disease in humans, such as the model systems described herein.

[0124] The actual dosage amount of a synthetic triterpenoid of the present disclosure or composition comprising a synthetic triterpenoid of the present disclosure administered to a patient may be determined by physical and physiological factors such as age, sex, body weight, severity of condition, the type of disease being treated, previous or concurrent therapeutic interventions, idiopathy of the patient and on the route of administration. These factors may be determined by a skilled artisan. The practitioner responsible for administration will typically determine the concentration of active ingredient(s) in a composition and appropriate dose(s) for the individual patient. The dosage may be adjusted by the individual physician in the event of any complication.

[0125] An effective amount typically will vary from about 0.001 mg/kg to about 1000 mg/kg, from about 0.01 mg/kg to about 750 mg/kg, from about 100 mg/kg to about 500 mg/kg, from about 1.0 mg/kg to about 250 mg/kg, from about 10.0 mg/kg to about 150 mg/kg in one or more dose administrations daily, for one or several days (depending of course of the mode of administration and the factors discussed above). Other suitable dose ranges include 1 mg to 10000 mg per day, 100 mg to 10000 mg per day, 500 mg to 10000 mg per day, and 500 mg to 1000 mg per day. In some particular embodiments, the amount is less than 10,000 mg per day with a range of 750 mg to 9000 mg per day.

[0126] The effective amount may be less than 1 mg/kg/day, less than 500 mg/kg/day, less than 250 mg/kg/day, less than 100 mg/kg/day, less than 50 mg/kg/day, less than 25 mg/kg/day or less than 10 mg/kg/day. It may alternatively be in the range of 1 mg/kg/day to 200 mg/kg/day. In other non-limiting examples, a dose may also comprise from about microgram/kg/body weight, about 5 microgram/kg/body weight, about 10 microgram/kg/body weight, about 50 microgram/kg/body weight, about 100 microgram/kg/body weight, about 200 microgram/kg/body weight, about 350 microgram/kg/body weight, about 500 microgram/kg/body weight, about 1 milligram/kg/body weight, about 5 milligram/kg/body weight, about 10 milligram/kg/body weight, about 50 milligram/kg/body weight, about 100 milligram/kg/body weight, about 200 milligram/kg/body weight, about 350 milligram/kg/body weight, about 500 milligram/kg/body weight, to about 1000 mg/kg/body weight or more per administration, and any range derivable therein. In non-limiting examples of a derivable range from the numbers listed herein, a range of about 5 mg/kg/body weight to about 100 mg/kg/body weight, about 5 microgram/kg/body weight to about 500 milligram/kg/body weight, etc., can be administered, based on the numbers described above.

[0127] Single or multiple doses of the synthetic triterpenoids are contemplated. Desired time intervals for delivery of multiple doses can be determined by one of ordinary skill in the art employing no more than routine experimentation. As an example, patients may be administered two doses daily at approximately 12 hour intervals. In some embodiments, the synthetic triterpenoid is administered once a day.

[0128] The synthetic triterpenoid may be administered on a routine schedule. As used herein a routine schedule refers to a predetermined designated period of time. The routine schedule may encompass periods of time which are identical or which differ in length, as long as the schedule is predetermined. For instance, the routine schedule may involve administration twice a day, every day, every two days, every three days, every four days, every five days, every six days, a weekly basis, a monthly basis or any set number of days or weeks there-between. Alternatively, the predetermined routine schedule may involve administration on a twice daily basis for the first week, followed by a daily basis for several months, etc. In other embodiments, the invention provides that the synthetic triterpenoid may taken orally and that the timing of which is or is not dependent upon food intake. Thus, for example, the synthetic triterpenoid can be taken every morning and/or every evening, regardless of when the patient has eaten or will eat.

[0129] The invention is described in greater detail by the following non-limiting examples.

EXAMPLE 1

Materials and Methods

[0130] Reagents. The synthesis of the triterpenoids has been described (Liby, et al. (2007) Nat. Rev. Cancer 7:357-69; Sporn, et al. (2011) J. Nat. Prod. 74:537-45). All other chemicals were from Sigma-Aldrich.

[0131] Calvarial Organ Cultures. Details have been published previously (Garrett, et al. (2003) J. Clin. Invest. 111:1771-82). Calvaria were cultured in BGJ medium supplemented with 1 mg/mL of bovine serum albumin (Cohn fraction V), 100 U/ml each of penicillin/streptomycin, and 0.292 mg/mL of glutamine. On Day 1, the calvaria were treated with synthetic oleanane triterpenoids. On Day 4, the medium was replaced with fresh medium, again containing synthetic oleanane triterpenoids. On Day 7, calvaria were collected, either stored at -80.degree. C. for further RNA analysis or fixed in 10% buffered formalin for 24 hours and transferred to 80% ethanol for histologic analysis.

[0132] Histologic Analysis of Calvaria. After fixation for 24 hours, calvaria were decalcified in EDTA, embedded in paraffin and sectioned at 4 .mu.m. Sections were stained either with modified hematoxylin and eosin (H&E) or with toluidine blue (1% in 70% ethanol for 20 minutes, followed by destaining in 70%, 90% and 100% ethanol for 15 seconds), placed in xylene twice, and then mounted. Procedures for immunofluorescence staining have been described (Medici, et al. (2010) Nat. Med. 74:537-45). Primary antibodies against collagen type II (AB746P, Millipore), were used at 1:100 dilution; ALEXFLUOR secondary antibodies (Invitrogen) at 1:200 dilution. For nuclear staining, To-PRO-3 Iodide (T3605, Invitrogen) was used.

[0133] Bone Marrow-Derived Stem Cell Culture and Immunoblotting. Human bone marrow-derived stromal cells, which contain a population of responsive mesenchymal stem cells (ScienCell Research Laboratories), were grown in mesenchymal stem cell medium (ScienCell Research Laboratories). Cells were serum-starved 24 hours prior to all experimental conditions. Immunoblotting was performed using the following antibodies at concentrations (and using protocols) recommended by the respective manufacturers: SOX9 (sc-20095, Santa Cruz Biotechnology), collagen II.alpha.1 (sc-7764 and sc-28887, Santa Cruz), aggrecan (ab3778 and ab36861, Abcam), BMP-2 (ab14933, Abcam), phospho-Smad5 (9516, Cell Signaling Technology), Smad5 (9517, Cell Signaling Technology), .beta.-actin (A1978, SigmaeAldrich). HRP-conjugated IgG TRUEBLOT reagents (18-8814, eBioscience) were used at a dilution of 1:1000.

[0134] Quantitative RT-PCR (qRT-PCR). Detailed procedures for qRT-PCR are known in the art (Lee, et al. (2006) Biochem. Pharmacol. 72:332-43). In brief, 30 ng of RNA was reverse transcribed to cDNA using the random primers and Applied Biosystems' High Capacity cDNA Archive Kit in a 96-well format MASTERCYCLER Gradient from EPPENDORF. Subsequently, cDNA was amplified with ASSAYS-ON-DEMAND Products containing two gene specific primers and one TAQMAN MGB probe (6-FAM dye-labeled) using the TAQMAN Universal PCR Master Mix in an ABI PRISM 7000 Sequencing Detector (Applied Biosystems). All labeled primers were obtained from Applied Biosystems.

EXAMPLE 2

Gene Expression and Cellular Differentiation

[0135] For the results described here, more than 300 individual calvarial organ cultures were performed. The analysis presented herein indicated that both CDDO-Im and CDDO-EA have marked ability to induce chondrogenesis in newborn mouse calvaria. Because it is membranous bone, the newborn calvarium does not manifest the chondrogenic phenotype, except for a very thin margin at suture lines; care was taken to avoid using suture areas of calvaria in any of the analyses described below. Treatment with either triterpenoid (200 nM) for 7 days clearly had a profound chondrogenic effect on the calvaria. No new cartilage was seen on control sections stained with either H&E or toluidine blue. In contrast, the metachromatic toluidine blue purple staining was indicative of the ability of CDDO-Im and CDDO-EA to induce the formation of proteoglycans, such as aggrecan, which are characteristic of cartilage (Roughley (2001) Arthritis Res. 3:342-7). With toluidine blue, bone stained orthochromatically (blue).

[0136] With respect to dose-response to either synthetic oleanane, 200 nM appeared to be optimal. Treatment with 50 nM triterpenoid yielded only marginal induction of chondrogenesis, while treatment with 500 nM synthetic oleanane gave somewhat variable results. Treatment with 1 mM triterpenoid was invariably toxic to the organ cultures. Results with 200 nM CDDO-Im and CDDO-EA were obtained in at least three sets of replicate experiments and immunohistochemistry showed that CDDO-Im and CDDO-EA (200 nM) both induced the formation of type II collagen (collagen II.alpha.1), which was not seen in the control sections.

[0137] In addition to the histologic analysis of the calvarial cultures, mechanistic aspects of the action of both CDDO-EA and CDDO-Im were investigated in the calvaria. After 7 days of culture, RNA was isolated from the calvaria and quantitative RT-PCR analysis was performed for more than 15 different markers, including: SOX9, collagen II.alpha.1, all three isoforms of TGF-.beta., BMPs 2 and 4, BMP receptor II, Smads 3, 4, 6, and 7, tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2), and matrix metalloproteinase-9 (MMP-9). Tables 2 and 3 show that essentially all of these markers (except MMP-9) were significantly up-regulated by both triterpenoids, when the calvaria were treated at either the 200 or the 500 nM dose. The 50 nM dose was generally ineffective. In contrast, both triterpenoids were strong inhibitors of the expression of MMP-9; CDDO-EA (200 nM) caused almost 80% inhibition of the expression of this metalloproteinase, which is known to be involved in the degradation of cartilage (Shinoda, et al. (2008) J. Biol. Chem. 283:24632-9).

TABLE-US-00002 TABLE 2 CDDO-Im Gene 50 nM 200 nM 500 nM SOX9 1.26 .+-. 0.08 1.33 .+-. 0.05 1.83 .+-. 0.13** COL2A1 1.45 .+-. 0.09 1.32 .+-. 0.23 1.72 .+-. 0.39 TGF-.beta.1 0.96 .+-. 0.07 1.08 .+-. 0.12 1.46 .+-. 0.12* TGF-.beta.2 1.17 .+-. 0.05 1.15 .+-. 0.09 1.17 .+-. 0.10 TGF-.beta.3 1.30 .+-. 0.07 1.52 .+-. 0.16** 1.66 .+-. 0.13** BMP-2 1.17 .+-. 0.07 1.60 .+-. 0.19 3.14 .+-. 0.53** BMP-4 0.97 .+-. 0.05 0.98 .+-. 0.06 1.35 .+-. 0.22 BMPRII 1.09 .+-. 0.06 1.22 .+-. 0.11 1.46 .+-. 0.14* Smad3 0.97 .+-. 0.07 0.90 .+-. 0.05 1.35 .+-. 0.19 Smad4 0.96 .+-. 0.06 1.03 .+-. 0.09 1.26 .+-. 0.09 Smad6 0.95 .+-. 0.05 1.23 .+-. 0.14 1.77 .+-. 0.19** Smad7 1.05 .+-. 0.07 1.320.14 1.78 .+-. 0.18** TIMP-1 1.43 .+-. 0.19 1.83 .+-. 0.18 3.00 .+-. 0.65** TIMP-2 1.24 .+-. 0.10 1.67 .+-. 0.19 2.62 .+-. 0.29** MMP-9 0.73 .+-. 0.16 0.44 .+-. 0.12** 0.26 .+-. 0.03**

TABLE-US-00003 TABLE 3 CDDO-ea Gene 50 nM 200 nM 500 nM SOX9 1.64 .+-. 0.17 2.62 .+-. 0.33** 3.12 .+-. 0.38** COL2A1 4.12 .+-. 1.78* 5.45 .+-. 1.13** 3.18 .+-. 0.71 TGF-.beta.1 1.17 .+-. 0.09 1.47 .+-. 0.24* 1.74 .+-. 0.17** TGF-.beta.2 1.36 .+-. 0.13* 1.61 .+-. 0.11** 1.88 .+-. 0.09** TGF-.beta.3 1.39 .+-. 0.07* 1.56 .+-. 0.13** 1.44 .+-. 0.11** BMP-2 1.53 .+-. 0.20 2.52 .+-. 0.29** 5.66 .+-. 0.67** BMP-4 1.28 .+-. 0.12 1.47 .+-. 0.13 2.49 .+-. 0.35** BMPRII 1.50 .+-. 0.14* 1.71 .+-. 0.19** 2.24 .+-. 0.22** Smad3 1.14 .+-. 0.12 1.35 .+-. 0.07 1.93 .+-. 0.16** Smad4 1.06 .+-. 0.03 1.37 .+-. 0.12** 1.89 .+-. 0.12** Smad6 1.09 .+-. 0.04 1.77 .+-. 0.24** 2.85 .+-. 0.31** Smad7 1.28 .+-. 0.10 1.86 .+-. 0.19** 3.06 .+-. 0.28** TIMP-1 1.88 .+-. 0.34 2.85 .+-. 0.38** 4.65 .+-. 0.38** TIMP-2 1.78 .+-. 0.18* 2.44 .+-. 0.31** 4.09 .+-. 0.36** MMP-9 0.49 .+-. 0.09** 0.22 .+-. 0.03** 0.19 .+-. 0.06**

[0138] Further studies on mechanism were pursued in human bone marrow stem cell (BMSC) cultures. Western blot analysis showed that CDDO-Im and CDDO-EA (each 100 nM for 7 days) induced expression of the chondrocyte markers, SOX9, collagen type 2, and aggrecan, none of which were detectable in the control cultured stem cells. Furthermore, both triterpenoids (also at 100 nM) rapidly induced expression of both BMP-2 and its relevant signal transduction protein, phospho-Smad5 (P-Smad5), in these stem cells. BMP-2 is known to induce chondrogenic lineage development of human mesenchymal stem cells in culture (Schmitt, et al. (2003) Differentiation 71:567-77).

Claims

1. A method for producing a stem or progenitor cell with induced gene expression comprising contacting a stem or progenitor cell with an effective amount of a synthetic triterpenoid to induce the expression of one or more of SOX9 (Sex determining region Y-box 9), COL2A1 (Type II Collagen (alpha1)), TGF (Transforming Growth Factor)-.beta.1, TGF-.beta.2, TGF-.beta.3, BMP (Bone Morphogenic Protein) 2, BMP4, BMPRII (Bone Morphogenic Protein Receptor II), SMAD (Small Mothers Against Decapentaplegic) 3, SMAD4, SMAD6, SMAD7, TIMP (Tissue Inhibitor of Metalloproteinase)-1 or TIMP-2 in the stem or progenitor cell, wherein the stem or progenitor cell is a mesenchymal stem cell, adipose tissue-derived mesenchymal stem cell, embryonic stem cell, stem cell from exfoliated deciduous teeth, periosteum cell, osteoprogenitor cell, or growth plate progenitor cell.

2. The method of claim 1, wherein the synthetic triterpenoid has the structure of Formula I: ##STR00005## wherein, X' and X.sup.2 are independently hydrogen, OR.sup.a, NR.sup.aR.sup.b, or SR.sup.a, wherein R.sup.a is a hydrogen, cyano, --CF.sub.3, nitro, amino, or substituted or unsubstituted heteroaryl group; R.sup.b is hydrogen, hydroxyl, alkyl, aryl, aralkyl, acyl, alkoxy, aryloxy, acyloxy, alkylamino, arylamino, amido, or a substituted version of any of these groups; or a substituent convertible in vivo to hydrogen; provided that R.sup.a is absent when the atom to which it is bound is part of a double bond, further provided that when R.sup.a is absent the atom to which it is bound is part of a double bond; Y is CH.sub.2 or CH.sub.2--CH.sub.2; Z is a covalent bond, --C(.dbd.O)--, alkanediyl, alkenediyl, alkynediyl, or a substituted version of any of these groups; the dashed bonds can be independently present or absent; R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently a hydrogen, hydroxyl, alkyl, substituted alkyl, alkoxy or substituted alkoxy group; R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9 and R.sup.10 are independently hydrogen, hydroxyl, halo, cyano, --C.dbd.CR.sup.a, --CO.sub.2R.sup.a, --COR.sup.a, alkyl, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl, acyl, alkoxy, aryloxy, acyloxy, alkylamino, arylamino, nitro, amino, amido, --C(O)R.sup.c or a substituted version of any of these groups, wherein R.sup.c is hydrogen, hydroxy, halo, amino, hydroxyamino, azido or mercapto; or C.sub.1-C.sub.15-alkyl, C.sub.2-C.sub.15-alkenyl, C.sub.2-C.sub.15-alkynyl, C.sub.6-C.sub.15-aryl, C.sub.7-C.sub.15-aralkyl, C.sub.1-C.sub.15-heteroaryl, C.sub.2-C.sub.15-heteroaralkyl, C.sub.1-C.sub.15-acyl, C.sub.1-C.sub.15-alkoxy, C.sub.2-C.sub.15-alkenyloxy, C.sub.2-C.sub.15-alkynyloxy, C.sub.6-C.sub.15-aryloxy, C.sub.7-C.sub.15-aralkyloxy, C.sub.1-C.sub.15-heteroaryloxy, C.sub.2-C.sub.15-heteroaralkyloxy, C.sub.1-C.sub.15-acyloxy, C.sub.1-C.sub.15-alkylamino, C.sub.2-C.sub.15-dialkylamino, C.sub.1-C.sub.15-alkoxyamino, C.sub.2-C.sub.15-alkenylamino, C.sub.2-C.sub.15-alkynylamino, C.sub.6-C.sub.15-arylamino, C.sub.7-C.sub.15-aralkylamino, C.sub.1-C.sub.15-heteroarylamino, C.sub.2-C.sub.15-heteroaralkylamino, C.sub.1-C.sub.15-alkylsulfonylamino, C.sub.1-C.sub.15-amido, C.sub.1-C.sub.15-alkylsilyloxy, or substituted versions of any of these groups; R.sup.5 and R.sup.6, R.sup.7 and R.sup.8, or R.sup.9 and R.sup.10 are independently taken together as .dbd.O; R.sup.11 and R.sup.12 are each independently hydrogen, hydroxyl, halo, alkyl , alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl, acyl, alkoxy, aryloxy, aralkoxy, heteroaryloxy, hetero-aralkoxy, acyloxy, alkylamino, dialkylamino, arylamino, aralkylamino, heteroarylamino, heteroaralkylamino, amido, or a substituted version of any of these groups, or R.sup.11 and R.sup.12 are taken together and are alkanediyl, alkenediyl, arenediyl, alkoxydiyl, alkenyloxydiyl, alkylaminodiyl, alkenylaminodiyl, or alkenylaminooxydiyl; R.sup.13 is hydrogen, hydroxy or oxo; R.sup.14 is hydrogen or hydroxyl; and R.sup.15 is a hydrogen, hydroxyl, --NR.sup.dR.sup.e, cyano, halo, azido, phosphate, 1,3-dioxoisoindolin-2-yl, mercapto, silyl or --COOH group, substituted or unsubstituted versions of C.sub.1-C.sub.15-alkyl, C.sub.2-C.sub.15-alkenyl, C.sub.2-C.sub.15-alkynyl, C.sub.6-C.sub.15-aryl, C.sub.7-C.sub.15-aralkyl, C.sub.1-C.sub.15-heteroaryl, C.sub.2-C.sub.15-heteroaralkyl, C.sub.1-C.sub.15-acyl, C.sub.1-C.sub.15-alkoxy, C.sub.2-C.sub.15-alkenyloxy, C.sub.2-C.sub.15-alkynyloxy, C.sub.6-C.sub.15-aryloxy, C.sub.7-C.sub.15-aralkyloxy, C.sub.1-C.sub.15-heteroaryloxy, C.sub.2-C.sub.15-heteroaralkyloxy, C.sub.1-C.sub.15-acyloxy, C.sub.1-C.sub.15-alkylamino, C.sub.2-C.sub.15-alkenylamino, C.sub.2-C.sub.15-alkynylamino, C.sub.6-C.sub.15-arylamino, C.sub.7-C.sub.15-aralkylamino, C.sub.1-C.sub.15-heteroarylamino, C.sub.2-C.sub.15-heteroaralkylamino, C.sub.1-C.sub.15-amido, C.sub.1-C.sub.15-alkylthio, C.sub.2-C.sub.15-alkenylthio, C.sub.2-C.sub.15-alkynylthio, C.sub.6-C.sub.15-arylthio, C.sub.7-C.sub.15-aralkylthio, C.sub.1-C.sub.15-heteroarylthio, C.sub.2-C.sub.15-heteroaralkylthio, C.sub.1-C.sub.15-acylthio, C.sub.1-C.sub.12-thioacyl, C.sub.1-C.sub.12-alkylsulfonyl, C.sub.2-C.sub.12-alkenylsulfonyl, C.sub.2-C.sub.12-alkynylsulfonyl, C.sub.6-C.sub.12-arylsulfonyl, C.sub.7-C.sub.12-aralkylsulfonyl, C.sub.1-C.sub.12-heteroarylsulfonyl, C.sub.1-C.sub.12-heteroaralkylsulfonyl, C.sub.1-C.sub.12-alkylsulfinyl, C.sub.2-C.sub.12-alkenylsulfinyl, C.sub.2-C.sub.12-alkynylsulfinyl, C.sub.6-C.sub.12-aryl sulfinyl, C.sub.7-C.sub.12-aralkylsulfinyl, C.sub.1-C.sub.12-heteroarylsulfinyl, C.sub.1-C.sub.12-heteroaralkylsulfinyl, C.sub.1-C.sub.12-alkylphosphonyl, C.sub.1-C.sub.12-alkylphosphate, C.sub.2-C.sub.12-dialkylphosphate, C.sub.1-C.sub.12-alkylammonium, C.sub.1-C.sub.12-alkylsulfonium, C.sub.1-C.sub.15-alkylsilyl, or a substituted version of any of these groups, a --CO.sub.2Me, carbonyl imidazole, --CO--D-Glu(OAc).sub.4, --CONH.sub.2, --CONHNH.sub.2, --CONHCH.sub.2CF.sub.3, or --C(.dbd.O)-heteroaryl group, or Z and R.sup.15 form a three to seven-membered ring, such that Z and R.sup.15 are further connected to one another through one or more of --O-- and alkanediyl, further wherein Z is --CH-- and R.sup.15 is --CH.sub.2-- or Z, R.sup.15, and carbon numbers 13, 17 and 18 form a ring such that R.sup.15 is bound to carbon 13, wherein Y is methanediyl or substituted methanediyl and R.sup.15 is --O--, wherein R.sup.d and R.sup.e are independently hydrogen, hydroxyl, alkyl, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, heteroaralkyl, acyl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, aralkoxy, heteroaryloxy, heteroaralkoxy, thioacyl, alkylsulfonyl, alkenylsulfonyl, alkynylsulfonyl, arylsulfonyl, aralkylsulfonyl, heteroarylsulfonyl, or heteroaralkylsulfonyl, or a substituted version of any of these groups.

3. The method of claim 1, wherein the stem or progenitor cell is multipotent.

4. A stem or progenitor cell produced by the method of claim 1.

5. A method for treating a degenerative disease or injury comprising transplanting into a patient suffering from a degenerative disease or injury a stem or progenitor cell of claim 4 thereby treating the patient's degenerative disease or injury, wherein the degenerative disease or injury is bone injury, cartilage injury, joint injury, dental disease, osteoarthritis, rheumatoid arthritis, degenerative disc disease, kyphosis, or osteopenia.

6. A method for treating a congenital disorder comprising transplanting into a patient suffering from a congenital disorder a stem or progenitor cell of claim 4 thereby treating the patient's congenital disorder, wherein the congenital disorder is scoliosis or a skeletal disorder.

7. A method for treating a degenerative disease or injury comprising administering to a patient suffering from a degenerative disease or injury an effective amount of a synthetic triterpenoid thereby treating the patient's degenerative disease or injury, wherein the degenerative disease or injury is bone injury, cartilage injury, joint injury, degenerative disc disease, dental disease, osteoarthritis, rheumatoid arthritis, kyphosis, or osteopenia.

8. A method for treating a congenital disorder comprising administering to a patient suffering from a congenital disorder an effective amount of a synthetic triterpenoid thereby treating the patient's congenital disorder, wherein the congenital disorder is scoliosis or a skeletal disorder.