Urokinase-type plasminogen activator negatively regulates α-smooth muscle actin expression via Endo180 and the uPA receptor in corneal fibroblasts
Urokinase-type plasminogen activator negatively regulates α-smooth muscle actin expression via Endo180 and the uPA receptor in corneal fibroblasts
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尿激酶型纤溶酶原激活剂通过 Endo180 和角膜成纤维细胞中的 uPA 受体负调节 α-平滑肌肌动蛋白表达
DOI：
10.1152/ajpcell.00432.2021
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发表时间：
2022
影响因子：
5.5
通讯作者：
Kusaka Shunji
中科院分区：
文献类型：
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作者：
Sugioka Koji;Nishida Teruo;Kodama-Takahashi Aya;Murakami Junko;Mano Fukutaro;Okada Kiyotaka;Fukuda Masahiko;Kusaka Shunji
角膜成纤维细胞嵌入在角膜基质中主要由1型胶原蛋白、蛋白聚糖和其他蛋白质组成的细胞外基质内，其形态和功能受到胶原蛋白的持续调节。在伤口愈合和各种病理条件下，角膜成纤维细胞分化为表达α-平滑肌肌动蛋白（α-SMA）的肌成纤维细胞。 Endo180，也称为尿激酶型纤溶酶原激活剂 (uPA) 受体相关蛋白 (uPARAP)，是一种胶原蛋白受体。在这里，我们通过在胶原凝胶或塑料上培养 uPA 缺陷 (uPA−/−) 或野生型 (uPA+/+) 小鼠的角膜成纤维细胞，研究 uPA 靶向 Endo180 和 uPA 受体 (uPAR) 是否可能在调节 α-SMA 表达中发挥作用。胶原凝胶培养条件下uPA−/−角膜成纤维细胞与uPA+/+细胞相比，α-SMA表达上调，全长Endo180和uPAR含量增加，转化生长因子-β（TGF-β）表达和Smad3磷酸化水平均较高。 Endo180 抗体抑制了 uPA 缺陷对 α-SMA 和 TGF-β 表达的影响，而 TGF-β 信号传导抑制剂则阻断了对 Smad3 磷酸化和 α-SMA 表达的影响。我们的结果表明，uPA 缺乏可能促进胶原蛋白和 Endo180 之间的相互作用，从而以依赖于 TGF-β 信号传导的方式增加 α-SMA 表达。因此，uPA 通过靶向 Endo180 和 uPAR 来负向调节 α-SMA 的表达。
Corneal fibroblasts are embedded within an extracellular matrix composed largely of collagen type 1, proteoglycans, and other proteins in the corneal stroma, and their morphology and function are subject to continuous regulation by collagen. During wound healing and in various pathological conditions, corneal fibroblasts differentiate into myofibroblasts characterized by the expression of α-smooth muscle actin (α-SMA). Endo180, also known as urokinase-type plasminogen activator (uPA) receptor-associated protein (uPARAP), is a collagen receptor. Here we investigated whether targeting of Endo180 and the uPA receptor (uPAR) by uPA might play a role in the regulation of α-SMA expression by culturing corneal fibroblasts derived from uPA-deficient (uPA−/−) or wild-type (uPA+/+) mice in a collagen gel or on plastic. The expression of α-SMA was upregulated, the amounts of full-length Endo180 and uPAR were increased, and the levels of both transforming growth factor-β (TGF-β) expression and Smad3 phosphorylation were higher inuPA−/−corneal fibroblasts compared withuPA+/+cells under the collagen gel culture condition. Antibodies to Endo180 inhibited these effects of uPA deficiency on α-SMA and TGF-β expression, whereas a TGF-β signaling inhibitor blocked the effects on Smad3 phosphorylation and α-SMA expression. Our results suggest that uPA deficiency might promote the interaction between collagen and Endo180 and thereby increase α-SMA expression in a manner dependent on TGF-β signaling. Expression of α-SMA is thus negatively regulated by uPA through targeting of Endo180 and uPAR.