Microtubule-dependent mechanism of anti-inflammatory effect of SOCS1 in endothelial dysfunction and lung injury.
Microtubule-dependent mechanism of anti-inflammatory effect of SOCS1 in endothelial dysfunction and lung injury.
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DOI：
10.1096/fj.202001477rr
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发表时间：
2021-04
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细胞因子信号转导抑制因子（SOCS）对炎症反应具有负调节作用。SOCS 1在控制急性肺损伤相关的内皮功能障碍和屏障损害中的作用和精确的细胞机制尚未探索。我们的研究结果表明，siRNA介导的SOCS 1敲低增强脂多糖（LPS）诱导的肺内皮细胞（EC）的通透性和增强炎症反应。与体外数据一致，EC特异性SOCS 1基因敲除小鼠发生了更严重的肺血管渗漏和支气管肺泡灌洗液中炎性细胞的积聚。SOCS 1过表达对LPS诱导的内皮通透性和炎症具有保护作用，这依赖于微管（MT）的完整性。未受刺激EC的生化和图像分析显示SOCS 1与MT相关，而LPS或MT解聚剂秋水仙碱的挑战损害了这种关联。SOCS 1直接与MT相关蛋白CLIP-170和CLASP 2的N2结构域相互作用。SOCS 1的N端是这些相互作用不可或缺的区域，缺失N端59个氨基酸的SOCS 1-ΔN突变体不能挽救LPS诱导的内皮功能障碍。内源性CLIP-170或CLASP 2的耗竭消除了SOCS 1与Toll样受体-4和Janus激酶-2的相互作用，导致SOCS 1对LPS诱导的炎症的抑制作用受损。总之，这些发现表明SOCS 1的内皮屏障保护和抗炎作用严重依赖于其靶向MT。
Suppressors of cytokine signaling (SOCS) provide negative regulation of inflammatory reaction. The role and precise cellular mechanisms of SOCS1 in control of endothelial dysfunction and barrier compromise associated with acute lung injury remain unexplored. Our results show that siRNA-mediated SOCS1 knockdown augmented lipopolysaccharide (LPS)-induced pulmonary endothelial cell (EC) permeability and enhanced inflammatory response. Consistent with in-vitro data, EC-specific SOCS1 knockout mice developed more severe lung vascular leak and accumulation of inflammatory cells in bronchoalveolar lavage fluid. SOCS1 overexpression exhibited protective effects against LPS-induced endothelial permeability and inflammation, which were dependent on microtubule (MT) integrity. Biochemical and image analysis of unstimulated EC showed SOCS1 association with the MT, while challenge with LPS or MT depolymerizing agent colchicine impaired this association. SOCS1 directly interacted with N2-domains of MT-associated proteins CLIP-170 and CLASP2. Furthermore, N-terminal region of SOCS1 was indispensable for these interactions and SOCS1-ΔN mutant lacking N-terminal 59 amino acids failed to rescue LPS-induced endothelial dysfunction. Depletion of endogenous CLIP-170 or CLASP2 abolished SOCS1 interaction with Toll-like receptor-4 and Janus kinase-2 leading to impairment of SOCS1 inhibitory effects on LPS-induced inflammation. Altogether, these findings suggest that endothelial barrier protective and anti-inflammatory effects of SOCS1 are critically dependent on its targeting to the MT.