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进行严格调节。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。这涉及到一些表面分子的活性，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syndecans，它们都经过金属蛋白酶ADAM17的脱落。通过细胞特异性敲除或药物抑制ADAM17，我们已经证明内皮和平滑肌表达ADAM17在小鼠急性肺炎症模型中的关键作用。ADAM17受到多种机制的严格调控。蛋白酶的转录诱导本身是不够的，需要进一步的翻译事件，包括从内质网到高尔基体的运输，蛋白酶的成熟和表面表达。很明显，这些事件严格依赖于ADAM17与菱形样假蛋白酶（iRhom1和2）的相互作用。我们最近观察到炎症刺激诱导iRhom2和血流条件诱导iRhom1的差异。我们可以证明内皮iRhom2的炎症上调导致ADAM17的成熟和表面表达增强。另一方面，流暴露内皮细胞中iRhom1的上调与ADAM15的诱导和表面表达增强相关。我们认为，肺组织中iRhom2的上调在促进炎症反应中起着关键作用，而iRhom1的高表达在非炎症条件下维持ADAM蛋白酶的一些表面表达可能更为重要。本研究的中心目的是研究iRhom1和2在分子、细胞和全身水平上在肺部炎症中的作用。体外研究解决了iRhoms在原代肺细胞类型（包括内皮细胞和平滑肌细胞）的炎症和生理反应中的不同作用。这包括内皮屏障功能、通透性改变、介质产生、平滑肌活化、白细胞转运和防止细胞凋亡。我们观察到，在炎症小鼠肺中，iRhom2而不是iRhom1上调。因此，我们希望进一步研究irhomm调节的时间动力学，并将其与LPS诱导炎症模型中的炎症事件联系起来。然后，我们将使用或生成敲除iRhom1和/或2或iRhom2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ADAM17致病功能的途径，从而支持靶向iRhom2治疗炎症性肺部疾病的基本原理。