Barja F, Coughlin C, Belin D, Gabbiani G
Lab Invest. 1986 Aug;55(2):226-33.
The relative levels of actin isoform synthesis in rat aortic smooth muscle cells (SMC) have been studied in vivo and in culture by means of [35S]methionine incorporation. They have been compared to the functional levels of actin isoform mRNAs, assayed by translation of total cell RNA in a reticulocyte lysate or, in some cases, to the actin isoform RNA content, assayed by Northern-blot hybridization to a total actin cRNA probe. In normal media and in freshly isolated SMC, the relative levels of actin isoform synthesis and the actin mRNA translation products show a remarkable similarity, but differ from the proportions of actin isoforms present in a total cell extract (Gabbiani G, Kocher O, Bloom WS, Vandekerckhove J, Weber K: Actin expression in smooth muscle cells of rat aortic intimal thickening, human atheromatous plaque, and cultured rat aortic media. J Clin Invest 73:148, 1984); (Skalli O, Bloom WS, Ropraz P, Azzarone B, Gabbiani G: Cytoskeletal remodeling of rat aortic smooth muscle cells in vitro: relationship to culture conditions and analogies to in vivo situations. J Submicrosc Cytol, in press 1986). This suggests that different actin isoforms have different stabilities. Fifteen days after balloon induced endothelial denudation in vivo, and after being placed in culture, SMC show a decrease in the proportions of alpha-actin synthesis and alpha-actin mRNA levels with a corresponding increase in these parameters for beta- and lambda-actins. The proportions of actin isoform synthesis and actin mRNA translation products in intimal SMC revert to normal values 60 days after balloon induced endothelial denudation, when the aorta is reendothelialized; however, in culture decreased alpha-actin synthesis and mRNA level persist up to the fifth passage (P5). These changes may be helpful for the understanding of SMC adaptation mechanisms during arterial development and atheromatous plaque formation.
通过[35S]甲硫氨酸掺入法，在体内和培养环境下研究了大鼠主动脉平滑肌细胞（SMC）中肌动蛋白异构体合成的相对水平。将其与肌动蛋白异构体mRNA的功能水平进行比较，通过在网织红细胞裂解物中翻译总细胞RNA来测定，在某些情况下，还与通过与总肌动蛋白cRNA探针进行Northern印迹杂交测定的肌动蛋白异构体RNA含量进行比较。在正常培养基和新鲜分离的SMC中，肌动蛋白异构体合成的相对水平与肌动蛋白mRNA翻译产物显示出显著的相似性，但与总细胞提取物中存在的肌动蛋白异构体比例不同（加比亚尼G、科赫尔O、布卢姆WS、万德克尔霍夫J、韦伯K：大鼠主动脉内膜增厚、人动脉粥样斑块和平滑肌细胞培养的大鼠主动脉中肌动蛋白的表达。《临床研究杂志》73:148，1984）；（斯卡利O、布卢姆WS、罗普拉兹P、阿扎罗内B、加比亚尼G：大鼠主动脉平滑肌细胞体外细胞骨架重塑：与培养条件的关系及与体内情况的类比。《亚微观细胞生物学杂志》，即将出版，1986）。这表明不同的肌动蛋白异构体具有不同的稳定性。在体内球囊诱导内皮剥脱15天后，并在培养后，SMC显示α-肌动蛋白合成比例和α-肌动蛋白mRNA水平降低，β-和λ-肌动蛋白的这些参数相应增加。当主动脉重新内皮化时，球囊诱导内皮剥脱60天后，内膜SMC中肌动蛋白异构体合成和肌动蛋白mRNA翻译产物的比例恢复到正常值；然而，在培养中，α-肌动蛋白合成和mRNA水平降低一直持续到第五代（P5）。这些变化可能有助于理解动脉发育和动脉粥样斑块形成过程中SMC的适应机制。
