The Ras homology (Rho) family of GTPases serves various functions, including promotion of cell migration, adhesion, and transcription, through activation of effector molecule targets. One such pair of effectors, the Rho‐associated coiled‐coil kinases (ROCK1 and ROCK2), induce reorganization of actin cytoskeleton and focal adhesion through substrate phosphorylation. Studies on ROCK knockout mice have confirmed that ROCK proteins are essential for embryonic development, but their physiological functions in adult mice remain unknown. In this study, we aimed to examine the roles of ROCK1 and ROCK2 proteins in normal adult mice. Tamoxifen (TAM)‐inducible ROCK1 and ROCK2 single and double knockout mice (ROCK1flox/flox and/or ROCK2flox/flox;Ubc‐CreERT2) were generated and administered a 5‐day course of TAM. No deaths occurred in either of the single knockout strains, whereas all of the ROCK1/ROCK2 double conditional knockout mice (DcKO) had died by Day 11 following the TAM course. DcKO mice exhibited increased lung tissue vascular permeability, thickening of alveolar walls, and a decrease in percutaneous oxygen saturation compared with noninducible ROCK1/ROCK2 double‐floxed control mice. On Day 3 post‐TAM, there was a decrease in phalloidin staining in the lungs in DcKO mice. On Day 5 post‐TAM, immunohistochemical analysis also revealed reduced staining for vascular endothelial (VE)‐cadherin, β‐catenin, and p120‐catenin at cell–cell contact sites in vascular endothelial cells in DcKO mice. Additionally, VE‐cadherin/β‐catenin complexes were decreased in DcKO mice, indicating that ROCK proteins play a crucial role in maintaining lung function by regulating cell–cell adhesion.

中文翻译：

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Rho 相关激酶的条件性缺陷会破坏成年小鼠的内皮细胞连接并损害呼吸功能

GTPases 的 Ras 同源 (Rho) 家族具有多种功能，包括通过激活效应分子靶标来促进细胞迁移、粘附和转录。其中一对效应器，Rho 相关卷曲螺旋激酶（ROCK1 和 ROCK2），通过底物磷酸化诱导肌动蛋白细胞骨架和粘着斑的重组。对ROCK基因敲除小鼠的研究证实，ROCK蛋白对于胚胎发育至关重要，但其在成年小鼠中的生理功能仍不清楚。在这项研究中，我们旨在研究 ROCK1 和 ROCK2 蛋白在正常成年小鼠中的作用。他莫昔芬 (TAM) 诱导的 ROCK1 和 ROCK2 单敲除和双敲除小鼠 (ROCK1弗洛克斯和/或 ROCK2弗洛克斯;Ubc-CreERT2) 是生成的，并进行了 5 天的 TAM 疗程。任一单一敲除品系均未发生死亡，而所有 ROCK1/ROCK2 双条件敲除小鼠 (DcKO) 均在 TAM 疗程后第 11 天死亡。与不可诱导的 ROCK1/ROCK2 双 flox 对照小鼠相比，DcKO 小鼠表现出肺组织血管通透性增加、肺泡壁增厚和经皮氧饱和度降低。 TAM 后第 3 天，DcKO 小鼠肺部的鬼笔环肽染色减少。 TAM 后第 5 天，免疫组织化学分析还显示，DcKO 小鼠血管内皮细胞的细胞-细胞接触位点的血管内皮 (VE)-钙粘蛋白、β-连环蛋白和 p120-连环蛋白染色减少。此外，DcKO 小鼠中 VE-钙粘蛋白/β-连环蛋白复合物减少，表明 ROCK 蛋白通过调节细胞间粘附在维持肺功能中发挥着至关重要的作用。