Kartha S, Bradham D M, Grotendorst G R, Toback F G
Department of Medicine, University of Chicago, Illinois 60637.
Am J Physiol. 1988 Oct;255(4 Pt 2):F800-6. doi: 10.1152/ajprenal.1988.255.4.F800.
Nontransformed monkey kidney cells (BSC-1 line), used as a model for renal epithelium, were assayed for release of platelet-derived growth factor (PDGF)-like proteins. BSC-1 cells continuously released a mitogenic activity for fibroblasts and a chemoattractant activity for smooth muscle cells, each of which was inhibited 80-90% by an antibody to human PDGF. A cDNA probe for the PDGF B-chain gene (c-sis), but not for the A-chain gene, hybridized to mRNA obtained from growing and quiescent cells. c-sis gene expression and PDGF-like protein secretion were studied in the presence of known growth-regulatory molecules. A secreted BSC-1 cell protein identical to transforming growth factor beta 2 inhibited DNA synthesis in growing cultures and induced marked accumulation of c-sis mRNA without a corresponding increase in the release of PDGF-like activity. Adenosine diphosphate stimulated DNA synthesis in quiescent cultures and enhanced both c-sis expression and release of PDGF-like activity. However, growing and quiescent cells did not express the PDGF receptor gene or exhibit a mitogenic response to authentic PDGF. Thus the PDGF-like protein released by these kidney epithelial cells could contribute to growth control by a paracrine mechanism.
作为肾上皮细胞模型的未转化猴肾细胞（BSC - 1系）被检测了血小板衍生生长因子（PDGF）样蛋白的释放情况。BSC - 1细胞持续释放对成纤维细胞的促有丝分裂活性以及对平滑肌细胞的趋化活性，这两种活性均被抗人PDGF抗体抑制80 - 90%。PDGF B链基因（c - sis）的cDNA探针，而非A链基因的探针，与从生长和静止细胞中获得的mRNA杂交。在已知生长调节分子存在的情况下，研究了c - sis基因表达和PDGF样蛋白分泌。一种与转化生长因子β2相同的分泌型BSC - 1细胞蛋白在生长培养物中抑制DNA合成，并诱导c - sis mRNA显著积累，而PDGF样活性的释放没有相应增加。二磷酸腺苷刺激静止培养物中的DNA合成，并增强c - sis表达和PDGF样活性的释放。然而，生长和静止细胞均不表达PDGF受体基因，也未表现出对 authentic PDGF的促有丝分裂反应。因此，这些肾上皮细胞释放的PDGF样蛋白可能通过旁分泌机制促进生长控制。
