- Type V collagen is a member of the subclass of fibrillar collagens that is present in minor amounts in virtually all non-cartilaginous connective tissues. As demonstrated by the applicant and others haploinsufficiency of pro-alpha1 (V) collagen chains frequently causes the classical form of Ehlers-Danlos syndrome (EDS I/II) which is characterized by joint laxity and dislocations, severe dermal fragility, and defective wound healing. Therefore, the biomechanical integrity of some connective tissues including skin, tendon, and ligaments appears to be exquisitely sensitive to the quantity of pro-alpha1 (V) chains available to participate in fibrillogenesis, yet other pro-alpha1(V)-containing tissues appear relatively unaffected. Experiments proposed by the applicant are designed to elucidate the role of type V collagen in regulating mechanical properties of tissues. In the first aim the products of pro-alpha1(V) expression genes containing C-propeptide mutations will be analyzed for their ability to self trimerize or to form trimers with wild-type pro-alpha1 (V) chains and pro-alpha2(V) chains. Binding of normal and mutant c-propeptides to chaperone proteins will be analyzed by chemical cross-linking and immunoprecipitation. Fibril shape and deposition of collagens and noncollagenous collagen-binding molecules will be measured in long-term dermal fibroblast cultures. In the second aim the molecular determinants of type V/XI chain selection will be analyzed by trimerization experiments in which full length or minigenes expressing the C-propeptides for pro-alpha1 (V), pro-alpha2 (V), and pro-alpha1 (XI) as well as a novel C-propeptide splice variant of pro-alpha1 (V) will be assembled in vitro and in cellulo after transfection in several cell types having restricted expression of type V/XI collagen chains. In the third aim homozygous and heterozygous col5A1 knockout mice will be analyzed for changes in type-specific collagen deposition in tissues and long-term fibroblast cultures from skin, which is severely affected in human col5A1 haploinsufficiency, and also in cornea, which appears to be spared even though type V collagen's role in collagen fibrillogenesis in cornea is well documented. In the fourth aim fibril morphology, biochemistry, and biomechanical characteristics of cornea and dermis in col5A1-deficient mice will be examined to determine the relationship between total type V collagen content, type V/type XI isoform ratios, noncollagenous protein content, and biomechanical properties.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR047054-04
Application #
6662714
Study Section
General Medicine A Subcommittee 2 (GMA)
Program Officer
Moshell, Alan N
Project Start
2000-08-21
Project End
2005-07-31
Budget Start
2003-08-01
Budget End
2005-07-31
Support Year
4
Fiscal Year
2003
Total Cost
$339,304
Indirect Cost
Name
Cincinnati Children's Hospital Medical Center
Department
Type
DUNS #
071284913
City
Cincinnati
State
OH
Country
United States
Zip Code
45229
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Wenstrup, Richard J; Florer, Jane B; Davidson, Jeffrey M et al. (2006) Murine model of the Ehlers-Danlos syndrome. col5a1 haploinsufficiency disrupts collagen fibril assembly at multiple stages. J Biol Chem 281:12888-95
Tinkle, Brad T; Wenstrup, Richard J (2005) A genetic approach to fracture epidemiology in childhood. Am J Med Genet C Semin Med Genet 139C:38-54
Wenstrup, Richard J; Florer, Jane B; Brunskill, Eric W et al. (2004) Type V collagen controls the initiation of collagen fibril assembly. J Biol Chem 279:53331-7
Dressler, M R; Butler, D L; Wenstrup, R et al. (2002) A potential mechanism for age-related declines in patellar tendon biomechanics. J Orthop Res 20:1315-22