Podocyte Integrin-β3 and Activated Protein C Coordinately Restrict RhoA Signaling and Ameliorate Diabetic Nephropathy
Podocyte Integrin-β3 and Activated Protein C Coordinately Restrict RhoA Signaling and Ameliorate Diabetic Nephropathy
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DOI：
10.1681/asn.2019111163
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发表时间：
2020-08-01
影响因子：
13.6
通讯作者：
Isermann, Berend
中科院分区：
文献类型：
--
作者：
Madhusudhan, Thati;Ghosh, Sanchita;Isermann, Berend
背景：糖尿病肾病（dNP）是目前ESKD的主要病因，缺乏有效的治疗方法。凝血蛋白酶依赖信号部分通过G蛋白偶联的蛋白酶激活受体（PARs）调节dNP。具体来说，细胞保护蛋白酶激活蛋白C （aPC）对dNP有保护作用，但其机制尚不清楚。方法采用体外实验和小鼠模型相结合的方法，评估apc -整合素相互作用及相关信号在dNP中的作用。结果酶原蛋白C和aPC与足细胞整合素β(3)结合，整合素β是整合素α (v) β(3)的一个亚基。这种整合素的缺乏会损害足细胞上凝血酶介导的aPC的产生。aPC与整合素- α (v) β(3)的相互作用诱导整合素- β(3)与G（α 13）的瞬时结合，并控制足细胞中par依赖性RhoA信号传导。aPC通过RGD序列与整合素- β(3)结合是足细胞中RhoA信号的时间限制所必需的。在缺乏整合素- β的足细胞中(3)，aPC诱导持续的RhoA激活，模拟凝血酶的作用。在体内，野生型aPC的过表达可抑制肾RhoA的病理性激活，并对dNP有保护作用。通过特异性地删除足细胞整合素- β(3)或通过去除aPC整合素结合的RGD序列来破坏aPC-整合素- β(3)的相互作用，可以增强高aPC水平小鼠的RhoA信号，并消除aPC的肾保护作用。关键凝血酶受体PAR1的药理学抑制可限制RhoA的激活，并对RGE-aPC（高）型和野生型小鼠具有肾保护作用。结论apc -整合素- α (v) β(3)在糖尿病肾病足细胞中起变阻器作用，控制par1依赖性RhoA激活。这些结果确定了整合素- α (v) β(3)是dNP中肾保护aPC- par信号所必需的aPC的重要辅助受体。
Background Diabetic nephropathy (dNP), now the leading cause of ESKD, lacks efficient therapies. Coagulation protease-dependent signaling modulates dNP, in part via the G protein-coupled, protease-activated receptors (PARs). Specifically, the cytoprotective protease-activated protein C (aPC) protects from dNP, but the mechanisms are not clear.Methods A combination of in vitro approaches and mouse models evaluated the role of aPC-integrin interaction and related signaling in dNP.Results The zymogen protein C and aPC bind to podocyte integrin-beta(3), a subunit of integrin-alpha(v)beta(3). Deficiency of this integrin impairs thrombin-mediated generation of aPC on podocytes. The interaction of aPC with integrin-alpha(v)beta(3) induces transient binding of integrin-beta(3) with G(alpha 13) and controls PAR-dependent RhoA signaling in podocytes. Binding of aPC to integrin-beta(3) via its RGD sequence is required for the temporal restriction of RhoA signaling in podocytes. In podocytes lacking integrin-beta(3), aPC induces sustained RhoA activation, mimicking the effect of thrombin. In vivo, overexpression of wild-type aPC suppresses pathologic renal RhoA activation and protects against dNP. Disrupting the aPC-integrin-beta(3) interaction by specifically deleting podocyte integrin-beta(3) or by abolishing aPC's integrin-binding RGD sequence enhances RhoA signaling in mice with high aPC levels and abolishes aPC's nephroprotective effect. Pharmacologic inhibition of PAR1, the pivotal thrombin receptor, restricts RhoA activation and nephroprotects RGE-aPC(high) and wild-type mice.Conclusions aPC-integrin-alpha(v)beta(3) acts as a rheostat, controlling PAR1-dependent RhoA activation in podocytes in diabetic nephropathy. These results identify integrin-alpha(v)beta(3) as an essential coreceptor for aPC that is required for nephroprotective aPC-PAR signaling in dNP.