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Decorin regulates assembly of collagen fibrils and acquisition of biomechanical properties during tendon development
Author(s) -
Zhang Guiyun,
Ezura Yoichi,
Chervoneva Inna,
Robinson Paul S.,
Beason David P.,
Carine Ehren T.,
Soslowsky Louis J.,
Iozzo Renato V.,
Birk David E.
Publication year - 2006
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.20776
Subject(s) - decorin , biglycan , fibrillogenesis , tendon , fibril , microbiology and biotechnology , extracellular matrix , chemistry , anatomy , biology , proteoglycan , biochemistry
Tendon function involves the development of an organized hierarchy of collagen fibrils. Small leucine‐rich proteoglycans have been implicated in the regulation of fibrillogenesis and decorin is the prototypic member of this family. Decorin‐deficient mice demonstrate altered fibril structure and mechanical function in mature skin and tail tendons. However, the developmental role(s) of decorin needs to be elucidated. To define these role(s) during tendon development, tendons (flexor digitorum longus) were analyzed ultrastructurally from postnatal day 10 to 90. Decorin‐deficient tendons developed abnormal, irregularly contoured fibrils. Finite mixture modeling estimated that the mature tendon was a three‐subpopulation mixture of fibrils with characteristic diameter ranges. During development, in each subpopulation the mean diameter was consistently larger in mutant mice. Also, diameter distributions and the percentage of fibrils in each subpopulation were altered. Biomechanical analyses demonstrated that mature decorin‐deficient tendons had significantly reduced strength and stiffness; however, there was no reduction in immature tendons. Expression of decorin and biglycan, a closely related family member, was analyzed during development. Decorin increased with development while biglycan decreased. Spatially, both had a comparable localization throughout the tendon. Biglycan expression increased substantially in decorin‐deficient tendons suggesting a potential functional compensation. The accumulation of structural defects during fibril growth, a period associated with decorin expression and low biglycan expression, may be the cause of compromised mechanical function in the absence of decorin. Our findings indicate that decorin is a key regulatory molecule and that the temporal switch from biglycan to decorin is an important event in the coordinate regulation of fibrillogenesis and tendon development. J. Cell. Biochem. © 2005 Wiley‐Liss, Inc.