Regulation of proteolysis by deubiquiting enzyme in lung inflammatory disease

摘要 肺内不受控制的细胞因子风暴会导致中性粒细胞大量涌入、毛细血管 渗漏、组织水肿和器官衰竭常表现为肺炎所致的急性肺损伤(ALI)。 溶血磷脂酸受体1(LPA1)是一种促炎性G蛋白偶联受体，可诱导促炎症反应。 G-α介导的信号转导及与内毒素受体CD14相互作用释放炎性细胞因子。 LPA1参与了肺炎性疾病的发病机制。击倒或抑制 LPA1可减轻内毒素或博莱霉素引起的肺损伤和败血症。我们发现LPA1的稳定性是 在泛素-溶酶体系统中进行调节。泛素特异性蛋白酶11(USP11)去泛素化和 稳定LPA1，从而促进LPA1调节的促炎作用。USP11基因敲除减少 LPA1稳定，并减轻LPA和内毒素诱导的肺部炎症。这是第一个演示 不稳定的LPA1可以减少肺部炎症，而去泛素化酶有助于 肺损伤的发病机制。我们已经开发出一种小分子封闭肽(LDPep)来中断这种相互作用 在LPA1和USP11之间，专门降低LPA1蛋白水平，而不改变其他基因的表达 LPA受体和USP11靶蛋白。低密度脂蛋白治疗后减轻内毒素性肺损伤 败血症休克。该项目将探索一种新的治疗方法来治疗炎症性疾病，如 阿里和败血症。这些研究的实施将为在机械方面取得重大进展奠定基础。 严重感染时促炎反应的分子调控。这些研究的结果可以 作为进一步开发破坏LPA1稳定的药理剂的基础，从而减少 炎症性疾病的严重程度，如肺损伤和败血症。

Abstract An uncontrolled cytokine storm in lungs leads to detrimental effects such as neutrophil influx, capillary leakage, tissue edema, and organ failure often manifested as pneumonia-induced acute lung injury (ALI). Lysophosphatidic acid receptor 1 (LPA1) is a pro-inflammatory G protein coupled receptor, which induces pro- inflammatory cytokine release through Gα-mediated signaling and interaction with endotoxin receptor, CD14. LPA1 has been implicated in the pathogenesis of lung inflammatory disorders. Knockdown or inhibition of LPA1 attenuates endotoxin- or bleomycin-induced lung injury and sepsis. We discovered that LPA1 stability is regulated in the ubiquitin-lysosome system. Ubiquitin-specific protease 11 (USP11) deubiquitinates and stabilizes LPA1, thus promoting LPA1-modulated pro-inflammatory effects. Knockdown of USP11 reduces LPA1 stability and attenuates both LPA- and LPS-induced lung inflammation. This is the first to demonstrate that destabilizing LPA1 reduces lung inflammation, and deubiquitinating enzyme contributes to the pathogenesis of lung injury. We have developed a small blocking peptide (LDPep) to interrupt the interaction between LPA1 and USP11, which specifically reduces LPA1 protein level, without altering expression of other LPA receptors and USP11 target proteins. LDPep post-treatment lessens endotoxin-induced lung injury and sepsis shock. This project will explore a novel therapeutic approach for treating inflammatory disorders like ALI and sepsis. Execution of these studies will lay the groundwork for a significant mechanistic advance in the molecular regulation of pro-inflammatory responses during severe infection. Results from these studies can serve as the basis for further development of pharmacologic agents that destabilize LPA1, thereby reducing severity of inflammatory diseases such as lung injury and sepsis.