McNeil P L, Muthukrishnan L, Warder E, D'Amore P A
Department of Anatomy and Cellular Biology, Harvard Medical School, Boston, Massachusetts 02115.
J Cell Biol. 1989 Aug;109(2):811-22. doi: 10.1083/jcb.109.2.811.
Growth factors may be required at sites of mechanical injury and normal wear and tear in vivo, suggesting that the direct action of mechanical forces on cells could lead to growth factor release. Scraping of cells from the tissue culture substratum at 37 degrees C was used to test this possibility. We show that scraping closely mimics in vitro both the transient plasma membrane wounds observed in cells subject to mechanical forces in vivo (McNeil, P. L., and S. Ito. 1989. Gastroenterology. 96:1238-1248) and the transient plasma membrane wounds shown here to occur in endothelial cells under normal culturing conditions. Scraping of endothelial cells from the culturing substratum released into the culture medium a potent growth-promoting activity for Swiss 3T3 fibroblasts. Growth-promoting activity was released rapidly (within 5 min) after scraping but was not subsequently degraded by the endothelial cells for at least 24 h thereafter. A greater quantity of growth-promoting activity was released by cells scraped 4 h after plating than by those scraped 4 or 7 d afterwards. Thus release is not due to scraping-induced disruption of extracellular matrix. Release was only partially cold inhibitable, was poorly correlated with the level of cell death induced by scraping, and did not occur when cells were killed with metabolic poisons. These results suggest that mechanical disruption of plasma membrane, either transient or permanent, is the essential event leading to release. A basic fibroblast growth factor-like molecule and not platelet-derived growth factor appears to be partially responsible for the growth-promoting activity. We conclude that one biologically relevant route of release of basic fibroblast growth factor, a molecule which lacks the signal peptide sequence for transport into the endoplasmic reticulum, could be directly through mechanically induced membrane disruptions of endothelial cells growing in vivo and in vitro.
在体内，机械损伤部位和正常磨损部位可能需要生长因子，这表明机械力对细胞的直接作用可能导致生长因子释放。在37摄氏度下从组织培养基质上刮下细胞，用于测试这种可能性。我们发现，刮擦在体外紧密模拟了体内受到机械力作用的细胞中观察到的瞬时质膜伤口（麦克尼尔，P.L.，和S.伊藤。1989年。《胃肠病学》。96:1238 - 1248）以及此处显示的在正常培养条件下内皮细胞中发生的瞬时质膜伤口。从培养基质上刮下内皮细胞后，释放到培养基中的物质对瑞士3T3成纤维细胞具有强大的促生长活性。刮擦后促生长活性迅速释放（5分钟内），但此后至少24小时内不会被内皮细胞降解。接种后4小时刮下的细胞释放的促生长活性比接种后4天或7天刮下的细胞更多。因此，释放不是由于刮擦引起的细胞外基质破坏。释放仅部分受冷抑制，与刮擦诱导的细胞死亡水平相关性较差，并且当细胞用代谢毒物杀死时不发生释放。这些结果表明，质膜的机械破坏，无论是瞬时的还是永久性的，都是导致释放的关键事件。一种碱性成纤维细胞生长因子样分子而非血小板衍生生长因子似乎部分负责这种促生长活性。我们得出结论，碱性成纤维细胞生长因子是一种缺乏转运到内质网的信号肽序列的分子，其释放的一条生物学相关途径可能直接通过体内和体外生长的内皮细胞的机械诱导膜破坏。
