Transforming growth factor-beta1 (TGF-beta1) regulates ATDC5 chondrogenic differentiation and fibronectin isoform expression.
Regulated splicing of fibronectin (FN) occurs during the mesenchymal to chondrocyte transition and ultimately results in the relative enrichment of an extra domain B (EDB) exon-containing FN isoform with the suggestion that FN isoforms may play a functional role in chondrogenesis. Promotion of chondrogenesis can also be achieved by treatment with transforming growth factor-beta (TGF-beta), which also regulates FN isoform expression. We have examined the effects of TGF-beta treatment on the assumption of the chondrogenic phenotype in the teratoma-derived cell line ATDC5 and tested whether these effects on chondrogenesis are paralleled by appropriate changes in FN isoform expression. ATDC5 cells were maintained in a pre-chondrogenic state and, in this state, treated with 10 ng/ml TGF-beta. The cells started to elaborate a matrix rich in sulfated proteoglycans, such that within the first 12 days of culture, TGF-beta1 treatment appeared to slightly accelerate early acquisition of an Alcian blue-stained matrix, and caused a dose- and time-dependent decrease in collagen type I expression; changes in collagen type II expression were variable. At later times, cells treated with TGF-beta became indistinguishable from those of the controls. Interestingly, TGF-beta treatment caused a significant dose- and time-dependent decrease in the proportion of FN containing the extra domain A (EDA) and the EDB exons. These data suggest that TGF-beta induces the early stages of chondrogenic maturation in this pre-chondrogenic line and that TGF-beta treatment increases expression of FN isoforms that lack the EDA and EDB exons.
Han
Fei
F
Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Adams
Christopher S
CS
Tao
Zhuliang
Z
Williams
Charlene J
CJ
Zaka
Raihana
R
Tuan
Rocky S
RS
Norton
Pamela A
PA
Hickok
Noreen J
NJ
D017398:Alternative Splicing / Q000187:drug effects; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D020219:Chondrogenesis / Q000187:drug effects* / Q000235:genetics; D024042:Collagen Type I / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism; D005091:Exons / Q000235:genetics; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D051379:Mice; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011509:Proteoglycans / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D013431:Sulfates / Q000737:chemistry; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
D024042:Collagen Type I; D024043:Collagen Type II; D005353:Fibronectins; D020033:Protein Isoforms; D011509:Proteoglycans; D012333:RNA, Messenger; D013431:Sulfates; C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1