Hardy M, Reddy U R, Pleasure D
Neurology Research, Children's Hospital of Philadelphia, PA 19104.
J Neurosci Res. 1992 Feb;31(2):254-62. doi: 10.1002/jnr.490310206.
To examine the role of platelet-derived growth factor (PDGF) in the in vivo regulation of Schwann cell proliferation, steady-state levels of mRNAs encoding PDGF A and B chains, and PDGF alpha and beta receptors were measured in immature and adult rat sciatic nerves and in cultured rat Schwann cells. PDGF B chain and PDGF beta receptor mRNAs are present in immature rat sciatic nerves and to a lesser extent in adult rat nerves. Short-term cultures of neonatal rat Schwann cells express PDGF beta receptor mRNA, but not PDGF B chain mRNA, and are stimulated to synthesize DNA by addition of PDGF BB to the medium. These data indicate that PDGF BB is a developmentally regulated paracrine growth factor for rat Schwann cells. Very long-term cultures of rat Schwann cells, which have lost normal dependence on exogenous growth factors, express PDGF B chain mRNA as well as mRNAs encoding the PDGF alpha and beta receptors, suggesting that, under these circumstances, PDGF BB also act as an autocrine growth factor. PDGF A chain mRNA is present in both immature and adult rat sciatic nerves and is expressed by primary and secondary cultures of rat Schwann cells as well. However, because the abundance of PDGF alpha receptor mRNA is very low in rat Schwann cells, PDGF AA is not likely to be a significant autocrine growth factor for rat Schwann cells.
为研究血小板衍生生长因子（PDGF）在雪旺细胞增殖的体内调节中的作用，我们检测了未成熟和成年大鼠坐骨神经以及培养的大鼠雪旺细胞中编码PDGF A链和B链以及PDGFα和β受体的mRNA的稳态水平。PDGF B链和PDGFβ受体mRNA存在于未成熟大鼠坐骨神经中，在成年大鼠神经中的含量较少。新生大鼠雪旺细胞的短期培养物表达PDGFβ受体mRNA，但不表达PDGF B链mRNA，向培养基中添加PDGF BB可刺激其合成DNA。这些数据表明，PDGF BB是大鼠雪旺细胞的一种受发育调节的旁分泌生长因子。长期培养的大鼠雪旺细胞已失去对外源生长因子的正常依赖性，它们表达PDGF B链mRNA以及编码PDGFα和β受体的mRNA，这表明在这些情况下，PDGF BB也作为一种自分泌生长因子起作用。PDGF A链mRNA存在于未成熟和成年大鼠坐骨神经中，大鼠雪旺细胞的原代和传代培养物也表达该mRNA。然而，由于大鼠雪旺细胞中PDGFα受体mRNA的丰度非常低，PDGF AA不太可能是大鼠雪旺细胞的重要自分泌生长因子。
