SHP-2调控肾小管上皮细胞先天性免疫应答参与肾缺血再灌注损伤的分子机制

Renal ischemia/reperfusion (I/R) injury is a common pathophysiology process in which innate immune response mediated by TLRs in parenchymal cells plays critical roles. Protein tyrosine phosphatase (PTP) is a kind of regulator regulating the signal transduction pathways of TLRs. Previous work showed that the expression and phosphatase activity of SHP-2 in tubular epithelial cells (TECs) were elevated after I/R stimulation, silencing SHP-2 resulted in up-regulated production of pro-inflammatory cytokines, indicating that SHP-2 might play important roles in renal I/R injury. To verify our hypothesis, TECs SHP-2 conditional knockout mice were introduced and renal I/R injury animal models were established. Next, we will test renal function and tubular injury, macrophage infiltration, TECs apoptosis, pro-inflammatory cytokines production, TLRs and their ligands expression, as well as the activation of MAPK and NF-κB signal transduction pathways after I/R. Through this study, the molecular mechanism of SHP-2 regulating TECs innate immune response in renal I/R injury will be explored and the theoretical basis for treatment of renal I/R injury will be provided.

肾缺血再灌注（I/R）损伤是一种常见的病理生理过程，实质细胞TLRs介导的先天性免疫应答在I/R损伤中发挥关键作用。蛋白酪氨酸磷酸酶作为调控因子精确调控TLRs信号转导，但其在肾I/R损伤中的作用尚不清楚。前期发现，体外模拟I/R后肾小管上皮细胞SHP-2表达及活性增高，沉默SHP-2可导致促炎性因子表达上调，提示SHP-2可能在肾I/R中发挥重要作用。为了证实这一推测，本课题组拟利用已有的肾小管上皮细胞SHP-2条件性敲除小鼠建立肾I/R损伤模型，检测肾功能及肾小管上皮损伤情况、肾脏巨噬细胞浸润、肾小管上皮细胞凋亡、促炎性因子表达、TLRs及其配体表达和MAPK、NF-κB信号通路的活化情况，揭示SHP-2调控肾小管上皮细胞先天性免疫应答干预肾I/R损伤的机制，为寻找治疗I/R损伤的靶点提供理论依据。

肾缺血再灌注（I/R）损伤是一种常见的病理生理过程，实质细胞TLRs介导的先天性免疫应答在I/R损伤中发挥关键作用。蛋白酪氨酸磷酸酶（PTP）作为调控因子精确调控TLRs信号转导，但其在肾I/R损伤中的作用尚不清楚。体外模拟I/R后肾小管上皮细胞SHP-2表达及活性增高，沉默SHP-2可导致促炎性因子表达上调，提示SHP-2在肾脏I/R中发挥重要作用。本课题组应用慢病毒转染技术沉默大鼠SHP-2基因并建立大鼠肾脏I/R模型。动物实验发现，与野生型大鼠相比，SHP-2沉默大鼠在肾脏I/R后肾小管损伤程度重，血清IL-6、TNF-α升高，肾组织TLR4、NF-κB p65、IL-6、TNF-α、Bax mRNA和蛋白表达升高而Bcl-2 mRNA和蛋白表达降低。分离培养肾脏I/R后野生型大鼠肾小管上皮细胞，慢病毒转染沉默SHP-2 基因。研究发现，与空白对照组及阴性对照组相比，SHP-2沉默组肾小管上皮细胞TLR4、NF-κB p65、IL-6、TNF-α、Bax mRNA和蛋白表达升高而Bcl-2 mRNA和蛋白表达降低，肾小管上皮细胞增殖降低、细胞凋亡增加，G0/G1期细胞比例升高而S期细胞比例降低。上述结果表明，肾小管上皮细胞SHP-2通过TLR4//NF-κB 通路调控炎性因子释放及细胞凋亡，在肾脏I/R损伤中发挥重要作用。本课题研究结果将为寻找治疗肾脏I/R损伤的靶点提供理论依据。