Gadson P F, Dalton M L, Patterson E, Svoboda D D, Hutchinson L, Schram D, Rosenquist T H
Department of Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha 68195-6395, USA.
Exp Cell Res. 1997 Feb 1;230(2):169-80. doi: 10.1006/excr.1996.3398.
Previously, we demonstrated that avian vascular smooth muscle cells (VSMC) derived from embryonic abdominal and thoracic aorta grow differently in the presence of transforming growth factor beta (TGF-beta1) and platelet-derived growth factor (PDGF-BB) (Wrenn et al., In Vitro Cell. Dev. Biol. 29, 73-78, 1992). The thoracic VSMC (N-VSMC) are derived from neural crest, and therefore differentiate from ectoderm; the abdominal VSMC (M-VSMC) are derived from mesoderm. The present study was designed to identify factors that mediate the differential responses of the VSMC to TGF-beta1. We found that TGF-beta1 increased DNA synthesis by approximately sevenfold in N-VSMC. Levels of both alpha1 (I) procollagen and c-myb mRNAs were markedly induced in N-VSMC treated with TGF-beta1. Chimeric plasmids containing up to 3.5 kb of alpha1 (I) procollagen 5' flanking DNA were induced to equivalent levels as procollagen mRNA in N-VSMC. However, TGF-beta1 increased DNA synthesis by threefold in M-VSMC; there was no effect on alpha1 (I) procollagen expression, and c-myb was not expressed, as demonstrated by immunohistochemistry staining and RNA analyses. Antisense c-myb oligodeoxynucleotides blocked the TGF-beta1 induction of alpha1 (I) procollagen and the growth of N-VSMC. The increase in DNA synthesis by M- and N-VSMC was correlated with the secretion of PDGF-AA, and staurosporine and antibodies directed against PDGF-AA suppressed DNA synthesis. Our results demonstrate that TGF-beta1 activity and c-myb expression modulate the expression of alpha1 (I) collagen and cell proliferation in neural crest-derived smooth muscle. The regulation of these events by TGF-beta1 may be important during morphogenesis of blood vessels and vascular diseases.
此前，我们证明了源自胚胎腹主动脉和胸主动脉的禽血管平滑肌细胞（VSMC）在转化生长因子β（TGF-β1）和血小板衍生生长因子（PDGF-BB）存在的情况下生长方式不同（Wrenn等人，《体外细胞与发育生物学》29，73 - 78，1992）。胸段VSMC（N-VSMC）源自神经嵴，因此由外胚层分化而来；腹段VSMC（M-VSMC）源自中胚层。本研究旨在确定介导VSMC对TGF-β1产生不同反应的因素。我们发现TGF-β1使N-VSMC中的DNA合成增加了约7倍。在用TGF-β1处理的N-VSMC中，α1（I）前胶原和c-myb mRNA的水平均显著诱导。含有长达3.5 kb的α1（I）前胶原5'侧翼DNA的嵌合质粒在N-VSMC中被诱导至与前胶原mRNA相当的水平。然而，TGF-β1使M-VSMC中的DNA合成增加了3倍；对α1（I）前胶原表达没有影响，免疫组织化学染色和RNA分析表明c-myb未表达。反义c-myb寡脱氧核苷酸阻断了TGF-β1对α1（I）前胶原的诱导以及N-VSMC的生长。M-VSMC和N-VSMC中DNA合成的增加与PDGF-AA的分泌相关联，星形孢菌素和针对PDGF-AA的抗体抑制了DNA合成。我们的结果表明，TGF-β1活性和c-myb表达调节神经嵴衍生平滑肌中α1（I）胶原的表达和细胞增殖。TGF-β1对这些事件的调节在血管形态发生和血管疾病过程中可能很重要。
