Regulation and Function of the Rhomboid Pseudoproteases iRhom1 and iRhom2 in Lung Inflammation

菱形伪蛋白酶 iRhom1 和 iRhom2 在肺部炎症中的调节和功能

• 批准号: 418426903
• 负责人: Professor Dr. Andreas Ludwig
• 金额: --
• 依托单位: Institut für Molekulare Pharmakologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/418426903?language=en
• 关键词: Regulation; Function; Rhomboid; Pseudoproteases; iRhom1

Lung inflammation can be critically modulated by limited proteolysis of cell surface molecules. These so called shedding processes regulate vascular permeability, edema formation, leukocyte recruitment, inflammatory mediator production and fibrotic responses. This involves the activity of several surface molecules such as TNF, EGF family members, IL-6 receptor, transmembrane chemokines, junctional cell adhesion molecules, or syndecans which all undergo shedding by the metalloprotease ADAM17. By cell specific knockout or pharmacological inhibition of ADAM17 we have demonstrated a critical role of endothelial and smooth muscle expressed ADAM17 in a murine model of acute lung inflammation. ADAM17 is known to be tightly regulated by several mechanism. Transcriptional induction of the protease is per se not sufficient and requires further translational events including the trafficking from the ER to the Golgi, maturation and surface expression of the protease. It became clear that these events strictly depend on the interaction of ADAM17 with the rhomboid like pseudoproteases (iRhom1 and 2). We recently observed differential induction of iRhom2 by inflammatory stimuli and iRhom1 by flow conditions. We could show that inflammatory upregulation of endothelial iRhom2 causes enhanced maturation and surface expression of ADAM17. On the other hand upregulation of iRhom1 in flow exposed endothelial cells correlated with enhanced induction and surface expression of ADAM15. We propose that the upregulation of iRhom2 in lung tissue plays a critical role in boosting the inflammatory response, while high expression of iRhom1 could be more important in maintaining some surface expression of ADAM proteases under non-inflammatory conditions. The central aim of this proposal is to study the role of iRhom1 and 2 in lung inflammation at molecular, cellular and systemic levels. The in vitro investigations address the differential role of iRhoms in inflammatory and physiological responses of primary lung cell types including endothelial and smooth muscle cells. This comprises endothelial barer function, permeability changes, mediator production, smooth muscle transactivation, leukocyte transmigration and protection against apoptosis. We observed that in inflamed mouse lungs iRhom2 rather than iRhom1 becomes upregulated. We therefore want to further investigate and correlate the time kinetics of iRhom regulation with the inflammatory events in our model of LPS induced inflammation. We will then use or generate new mice with knockout of iRhom1 and/or 2 or iRhom2 overexpression and investigate them for vascular permeability, mediator production, leukocyte recruitment and fibrotic responses. We expect that our findings allow a deeper understanding of the pathways promoting pathogenic functions of ADAM17 which in turn could support the rationale to target iRhom2 in inflammatory lung diseases.

肺部炎症可以通过细胞表面分子的有限蛋白水解来关键地调节。这些所谓的脱落过程调节血管通透性、水肿形成、白细胞募集、炎症介质产生和纤维化反应。 这涉及几种表面分子的活性，例如TNF、EGF家族成员、IL-6受体、跨膜趋化因子、连接细胞粘附分子或多配体蛋白聚糖，它们都经历金属蛋白酶ADAM 17的脱落。通过细胞特异性敲除或药物抑制ADAM 17，我们已经证明了内皮和平滑肌表达的ADAM 17在急性肺部炎症小鼠模型中的关键作用。已知ADAM 17受几种机制的严格调控。蛋白酶的转录诱导本身是不够的，需要进一步的翻译事件，包括从ER到高尔基体的运输，蛋白酶的成熟和表面表达。很明显，这些事件严格依赖于ADAM 17与菱形样假蛋白酶（iRhom 1和2）的相互作用。我们最近观察到差异诱导iRhom 2的炎症刺激和iRhom 1的流动条件。我们可以表明，内皮iRhom 2的炎症性上调导致ADAM 17的成熟和表面表达增强。另一方面，iRhom 1在血流暴露的内皮细胞中的上调与ADAM 15的诱导和表面表达增强相关。我们认为肺组织中iRhom 2的上调在促进炎症反应中起着关键作用，而iRhom 1的高表达在非炎症条件下维持一些ADAM蛋白酶的表面表达可能更重要。该提案的中心目的是研究iRhom 1和2在分子、细胞和系统水平上在肺部炎症中的作用。体外研究解决了iRhoms在包括内皮细胞和平滑肌细胞在内的原代肺细胞类型的炎症和生理反应中的不同作用。这包括内皮细胞功能、渗透性变化、介质产生、平滑肌反式激活、白细胞迁移和抗凋亡保护。我们观察到，在发炎的小鼠肺中，iRhom 2而不是iRhom 1被上调。因此，我们希望进一步研究iRhom调节的时间动力学并将其与我们的LPS诱导的炎症模型中的炎症事件相关联。然后，我们将使用或产生敲除iRhom 1和/或iRhom 2或iRhom 2过表达的新小鼠，并研究它们的血管通透性、介质产生、白细胞募集和纤维化反应。我们希望我们的研究结果能够更深入地了解促进ADAM 17致病功能的途径，这反过来又可以支持在炎症性肺病中靶向iRhom 2的基本原理。