The combination of a growth factor capable of effecting the regeneration of a tissue with a matrix suitable to act as a scaffold for that tissue is a central tenet in tissue engineering. We propose to test this hypothesis by developing prototype tissue engineering biomaterials for in vivo and in vitro proof of concept studies. Connective tissue growth factor (CTGF), a key fibrogenic growth factor, acts downstream of TGF- beta to promote mesenchymal cell proliferation and to stimulate extracellular matrix deposition. Our recent data suggest a role in development and differentiation of cartilage, skin and bone. Uses of CTGF in tissue engineering applications are unexplored. Strength, persistence and biocompatibility are unique and inherent properties of collagens that make these proteins well suited as scaffolds for these studies. Although animal-derived collagens are available and most frequently used as biomaterials, there are increasing concerns about their purity, safety and immunogenicity. Of the 20 known collagens, only type 1 collagen has been evaluated as a biomaterial, again because it is the only collagen economically extracted from tissue. Until recently, recombinant expression of human collagens has been difficult due to the significant post translational modifications needed for function. Our success with collagen expression technology now provides a means to generate and explore uses of the rarer, tissue-specific human collagens such as types II (predominant in cartilage) and III (prominent in vessels). To evaluate recombinant human collagens and CTGF as components of tissue engineering therapeutics we specifically will: 1) produce recombinant human collagen types I, II, and III in a cost effective, commercially viable yeast expression system. This will involve expression, purification, formulation and characterization; 2) evaluate biocompatibility of the recombinant human collagens compared to tissue- derived materials; 3) investigate in vitro how matching mesenchymal cell type and collagen matrix affects cell attachment, differentiation, migration, proliferation and survival and also determine the effects of including CTGF in these scaffolds; and, 4) evaluate these CTGF augmented scaffolds in tissue engineering applications using in vivo models of tissue repair and regeneration that focus on cartilage, bone and skin. The momentum of our ongoing programs and commitments in related areas will leverage additional support to expedite the development of these novel therapeutic prototypes that are capable of addressing significant medical needs. In addition, further avenues for research and development, based on novel combinations of cytokines and engineered and/or tissue-specific collagens, will have been identified.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
1R01AR045879-01
Application #
2797400
Study Section
Special Emphasis Panel (ZHL1-CSR-F (M1))
Project Start
1998-09-28
Project End
2003-08-31
Budget Start
1998-09-28
Budget End
1999-08-31
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Fibrogen, Inc.
Department
Type
DUNS #
City
San Francisco
State
CA
Country
United States
Zip Code
94158
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Olsen, David; Yang, Chunlin; Bodo, Michael et al. (2003) Recombinant collagen and gelatin for drug delivery. Adv Drug Deliv Rev 55:1547-67
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Leask, Andrew; Holmes, Alan; Abraham, David J (2002) Connective tissue growth factor: a new and important player in the pathogenesis of fibrosis. Curr Rheumatol Rep 4:136-42
Leask, A; Abraham, D J; Finlay, D R et al. (2002) Dysregulation of transforming growth factor beta signaling in scleroderma: overexpression of endoglin in cutaneous scleroderma fibroblasts. Arthritis Rheum 46:1857-65
Ruangpanit, N; Chan, D; Holmbeck, K et al. (2001) Gelatinase A (MMP-2) activation by skin fibroblasts: dependence on MT1-MMP expression and fibrillar collagen form. Matrix Biol 20:193-203

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