Shimizu Y, Dobashi K, Iizuka K, Horie T, Suzuki K, Tukagoshi H, Nakazawa T, Nakazato Y, Mori M
First Department of Internal Medicine, Gunma University Faculty of Medicine, School of Medicine, Gunma University School of Health Sciences, Gunma, Japan.
Am J Respir Crit Care Med. 2001 Jan;163(1):210-7. doi: 10.1164/ajrccm.163.1.2001089.
Excess fibroblasts and inflammatory cells may play an important role in the pathogenesis of idiopathic pulmonary fibrosis (IPF). The small GTPase, Rho, and its target protein, Rho-associated coiled-coil-forming protein kinase (ROCK), have been recognized to be major regulators of cell locomotion mediated by reorganization of the actin cytoskelton. Activated ROCK inhibits myosin phosphatase, and this in turn induces phosphorylation of the myosin light chain (MLC). To determine the mechanisms underlying the deterioration process of IPF, we investigated the effect of Y-27632, a selective ROCK inhibitor, in a murine model of bleomycin (BLM)-induced lung fibrosis. The Aschcroft score and hydroxyproline content of the BLM-treated mouse lung decreased in response to Y-27632 treatment. The number of broncoalveolar cells was decreased by Y-27632, and migration of macrophages, neutrophils, and fibroblasts in vitro was inhibited by Y-27632 regardless of various stimuli. Although expression of ROCK-II mRNA in the lung homogenates of the BLM-treated mice was increased approximately 9-fold, expression of ROCK-II protein showed only a slight tendency to increase. BLM elevated MLC phosphorylation levels, and Y-27632 inhibited BLM response. These findings indicate that the Rho/ROCK-mediated pathway plays an important role in IPF, and that blocking of this pathway leads to inhibition of IPF development.
过量的成纤维细胞和炎症细胞可能在特发性肺纤维化（IPF）的发病机制中起重要作用。小GTP酶Rho及其靶蛋白Rho相关卷曲螺旋形成蛋白激酶（ROCK）已被认为是由肌动蛋白细胞骨架重组介导的细胞运动的主要调节因子。活化的ROCK抑制肌球蛋白磷酸酶，进而诱导肌球蛋白轻链（MLC）磷酸化。为了确定IPF恶化过程的潜在机制，我们在博来霉素（BLM）诱导的小鼠肺纤维化模型中研究了选择性ROCK抑制剂Y-27632的作用。Y-27632处理后，BLM处理的小鼠肺组织的阿什克罗夫特评分和羟脯氨酸含量降低。Y-27632减少了支气管肺泡细胞的数量，并且无论各种刺激如何，Y-27632在体外均抑制巨噬细胞、中性粒细胞和成纤维细胞的迁移。尽管BLM处理的小鼠肺匀浆中ROCK-II mRNA的表达增加了约9倍，但ROCK-II蛋白的表达仅略有增加趋势。BLM提高了MLC磷酸化水平，而Y-27632抑制了BLM反应。这些发现表明，Rho/ROCK介导的途径在IPF中起重要作用，阻断该途径可导致IPF发展的抑制。
