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Decreased steady‐state insulin‐like growth factor binding protein‐3 (IGFBP‐3) mRNA level is associated with differentiation of cultured porcine myogenic cells
Author(s) -
Johnson B.J.,
White M.E.,
Hathaway M.R.,
Dayton W.R.
Publication year - 1999
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/(sici)1097-4652(199905)179:2<237::aid-jcp15>3.0.co;2-g
Subject(s) - insulin like growth factor binding protein , messenger rna , biology , growth factor , cell culture , cellular differentiation , cell growth , myocyte , endocrinology , insulin like growth factor , medicine , microbiology and biotechnology , gene , biochemistry , receptor , genetics
Insulin‐like growth factor binding proteins (IGFBPs) affect the biological activity of IGF‐I in several cell types, including cultured muscle cells. Additionally, at least one of the IGFBPs, IGFBP‐3, has been shown to have IGF‐independent effects on cell proliferation. Numerous studies have shown that immortalized muscle cell lines produce various IGFBPs, but to date no muscle cell line has been reported to produce IGFBP‐3 protein or mRNA. Unlike muscle cell lines, primary cultures of porcine embryonic myogenic cells express IGFBP‐3 mRNA and secrete a protein that is immunologically identifiable as IGFBP‐3. Additionally, steady‐state IGFBP‐3 levels change significantly during differentiation. Here we report that differentiation of porcine myogenic cells in an IGFBP‐3–free medium is accompanied by reduced steady‐state IGFBP‐3 mRNA levels. Steady‐state levels of IGFBP‐3 mRNA decreased approximately sevenfold ( P < .05) during differentiation and then increased to predifferentiation levels once differentiation was complete. Addition of TGF‐β 1 (0.5 ng/ml) to porcine myogenic cultures suppressed fusion and resulted in a sevenfold increase in steady‐state IGFBP‐3 mRNA and a 1.8‐fold increase in IGFBP‐3 protein levels as compared to untreated control cultures ( P < .05). Results suggest that alterations in IGFBP‐3 mRNA and protein may play a role in differentiation of porcine embryonic muscle cells. J. Cell. Physiol. 179:237–243, 1999. © 1999 Wiley‐Liss, Inc.