Premium
F‐spondin, a neuroregulatory protein, is up‐regulated in osteoarthritis and regulates cartilage metabolism via TGF‐β activation
Author(s) -
Attur Mukundan G.,
Palmer Glyn D.,
AlMussawir Hayf E.,
Dave Mandar,
Teixeira Cristina C.,
Rifkin Daniel B.,
Appleton C. Thomas G.,
Beier Frank,
Abramson Steven B.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.08-114363
Subject(s) - cartilage , osteoarthritis , extracellular matrix , proteoglycan , chemistry , microbiology and biotechnology , thrombospondin , medicine , endocrinology , matrix metalloproteinase , anatomy , biology , pathology , biochemistry , metalloproteinase , alternative medicine
In osteoarthritis (OA) articular chondrocytes undergo phenotypic changes culminating in the progressive loss of cartilage from the joint surface. The molecular mechanisms underlying these changes are poorly understood. Here we report enhanced (‐7‐fold) expression of F‐spondin, a neuronal extracellular ma‐trix glycoprotein, in human OA cartilage (P<0.005). OA‐specific up‐regulation of F‐spondin was also dem‐onstrated in rat knee cartilage following surgical meni‐sectomy. F‐spondin treatment of OA cartilage explants caused a 2‐fold increase in levels of the active form of TGF‐β1(P<0.01) and a 10‐fold induction of PGE2 ( P< 0.005) in culture supernatants. PGE2 induction was found to be dependent on TGF‐β and the throm‐bospondin domain of the F‐spondin molecule. F‐spondin addition to cartilage explant cultures also caused a 4‐fold increase in collagen degradation (P< 0.05) and a modest reduction in proteoglycan synthesis (~20%;P<0.05), which were both TGF‐β and PGE2 dependent. F‐spondin treatment also led to increased secretion and activation of MMP‐13 (P<0.05). Together these studies identify F‐spondin as a novel protein in OAcartilage, where it may act in situ at lesional areas to activate latent TGF‐β and induce cartilage degradation via pathways that involve production of PGE2.—Attur, M. G., Palmer, G. D., Al‐Mussawir, H. E., Dave, M., Teixeira, C. C., Rifkin, D. B., Appleton, C. T. G., Beier, F., Abramson, S. B. F‐spondin, a neuroregulatory protein, is up‐regulated in osteoarthritis and regulates cartilage metabolism via TGF‐β activation. FASEB J. 23, 79‐89 (2009)