TRANSFORMING GROWTH-FACTOR-BETA, BASIC FIBROBLAST GROWTH-FACTOR, AND PLATELET-DERIVED GROWTH FACTOR-BB INTERACT TO AFFECT PROLIFERATION OF CLONALLY DERIVED PORCINE SATELLITE CELLS

Transforming growth factor beta-1 (TGF-beta) stimulated porcine satell ite cell proliferation in basal serum-free medium by 25%, but inhibite d growth in serum-containing medium by 58%. The effect of TGF-beta on cell proliferation in serum-free medium was examined in combination wi th the following human recombinant growth factors: platelet-derived gr owth factor-BB (PDGF), basic fibroblast growth factor (FGF), insulin-l ike growth factor I (IGF-I), and epidermal growth factor (EGF). TGF-be ta inhibited PDGF-stimulated proliferation, enhanced FGF-stimulated pr oliferation, and had no effect on proliferation stimulated by IGF-1. T he response of satellite cells to EGF and TGF-beta in serum-free mediu m was not different than TGF-beta alone. TGF-beta depressed proliferat ion stimulated by the following combinations of two growth factors: PD GF and IGF-I, PDGF and EGF, PDGF and FGF, and IGF-I and EGF. In combin ation with IGF-I and FGF, TGF-beta did not affect proliferation. TGF-b eta inhibited proliferation stimulated by the combination of PDGF, EGF , and IGF-1, but had no effect on proliferation stimulated by combinat ions of three growth factors that included FGF. FGF stimulated prolife ration in Minimum Essential Medium containing 10% porcine serum (MEM-1 0% PS) by 13% above control. When the combination of TGF-beta and FGF was added to MEM-10% PS, a 78% increase in proliferation was observed. Polyclonal antihuman PDGF-AB (this form neutralizes PDGF-AA, AB, and BB) reduced proliferation in MEM-10% PS by 44%. The combination of TGF -beta and anti-PDGF-AB reduced proliferation by 59%, indicating the ef fects were not additive. These data indicate that: (1) FGF and TGF-bet a interact to increase proliferation of clonally derived porcine satel lite cells, and (2) the inhibitory effect of TGF-beta on proliferation of clonally derived porcine satelite cells can be primarily attribute d to a reduction in the mitogenic effects of PDGF. (C) 1993 Wiley-Liss , Inc.