Expression of basic fibroblast growth factor and fibroblast growth factor receptor genes in cultured rat aortic smooth muscle cells

Basic fibroblast growth factor (bFGF) exerts a differential effect on DNA synthesis, bFGF mRNA synthesis, and expression of FGF-receptor genes by cultured smooth muscle cells from aortae of newborn and adult rats (used as a model in atherosclerosis research). Cells from adult animals, are more sensitive to bFGF, and bFGF triggers its own mRNA synthesis. Moreover, the level of the transcript of the FGFR-1 gene (coding for the most abundant FGF-receptor in smooth muscle cells) is higher in smooth muscle cells from adult rats. In contrast, the FGFR-3 gene only is expressed in smooth muscle cells from newborn rats. Crosslinking of [125I]bFGF to its receptor showed 130 kDa and 160 kDa complexes both in newborn and adult smooth muscle cells

Effect of ploidy on transcription levels in cultured rat aortic smooth muscle cells

Aging and hypertension increase the number of polyploid smooth muscle cells (SMC) in a blood vessel. We assessed the effect of ploidy on the transcription of several genes in SMC cultures derived from newborn and adult rats. In diploid and tetraploid subcultures of SMC from newborn rats, RNA expression of the genes assayed is linked with ploidy. However, when phenotypically different SMC cultures derived from newborn and adult rats were compared, transcription levels varied from gene to gene and not linked with the ploidy. Thus, differences in gene expression due to polyploidy are superimposed on those due to other phenotypical features

Basic fibroblast growth factor has a differential effect on MyoD conversion of cultured aortic smooth muscle cells from newborn and adult rats

MyoD is a master regulatory gene for myogenesis that also converts many mesoderm-derived cells into the skeletal muscle phenotype. Rat aortic smooth muscle cells do not contain MyoD homologous mRNA. However, expression of an exogenously supplied MyoD gene in aortic smooth muscle cells cultured from newborn and adult animals converts these cells to elongated myoblasts and myotubes expressing the skeletal muscle genes for titin, nebulin, myosin, and skeletal α-actin. The presence of basic fibroblast growth factor during growth and serum starvation completely inhibits MyoD-mediated conversion in cultures of newborn smooth muscle cells. However, in smooth muscle cell cultures derived from adult rats the presence of fibroblast growth factor increases the conversion frequency. The differential response of exogenous MyoD suggests that the two morphological types of aortic smooth muscle cells, one typical for the newborn rat, the other for the adult rat, represent two distinctive states of differentiation.</p

Basic fibroblast growth factor has a differential effect on MyoD conversion of cultured aortic smooth muscle cells from newborn and adult rats

MyoD is a master regulatory gene for myogenesis that also converts many mesoderm-derived cells into the skeletal muscle phenotype. Rat aortic smooth muscle cells do not contain MyoD homologous mRNA. However, expression of an exogenously supplied MyoD gene in aortic smooth muscle cells cultured from newborn and adult animals converts these cells to elongated myoblasts and myotubes expressing the skeletal muscle genes for titin, nebulin, myosin, and skeletal α-actin. The presence of basic fibroblast growth factor during growth and serum starvation completely inhibits MyoD-mediated conversion in cultures of newborn smooth muscle cells. However, in smooth muscle cell cultures derived from adult rats the presence of fibroblast growth factor increases the conversion frequency. The differential response of exogenous MyoD suggests that the two morphological types of aortic smooth muscle cells, one typical for the newborn rat, the other for the adult rat, represent two distinctive states of differentiation