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Hypertrophic chondrocyte production and secretion of a unique TGFb2 large latent complex
Author(s) -
Dragann Brendan N,
Day Shaila E,
Mentzer Brittany M,
Appelt Denah,
Scheinfeld Victoria L.,
Mattioli Patrisia M,
D’Angelo Marina
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/fasebj.21.6.a972-c
Our lab has shown that hypertrophic chondrocytes produce a unique TGFb2 large latent complex that contains MMP13 in non‐covalent association with latent TGFb binding protein (LTBP1). In this study, we investigate hypertrophic chondrocyte production of the individual elements of this unique TGFb2 large latent complex. Hypertrophic chondrocytes from the avian sterna were cultured 5 days in serum‐free alginate. RNA, conditioned media, cell‐associated matrix (isolated after release of the chondrocytes from alginate), and cell extracts were analyzed for TGFb2, MMP13 and LTBP1. Hypertrophic chondrocytes produced message for TGFb2, MMP13 and the short from of LTBP1. Immunoblot analysis revealed the presence of immunoreactive bands for TGFb2, MMP13 and LTBP1 in the cellular extracts. Assembly into the extracellular matrix and secretion of the components was indicated by the presence of immunoreactive bands for TGFb2, MMP13 and LTBP1 in the cell‐associated matrix and conditioned media fraction. Zymography revealed active MMP13 enzyme in all of the fractions with the most activity present in the conditioned media fraction. Immunocytochemistry demonstrated the presence of TGFb2 and MMP13 in association with the cells and pericellular LTBP staining . These data indicate that the components of the unique TGFb2 large latent complex are produced and secreted by hypertrophic chondrocytes and are present in compartments that are characteristic of extracellular matrix assembly.