尿调蛋白抑制补体活化在糖尿病肾病中的保护作用研究

肾小管损伤在糖尿病肾病(DKD)发病及进展中起重要作用。补体过度活化诱发下游炎症是DKD进展的重要机制。肾小管髓袢升支粗段到远曲小管是重要调节区，尿调蛋白(UMOD)表达于该部位上皮细胞，分泌到尿和血中，是肾脏的保护因子。UMOD可通过和补体成分相互作用，抑制补体过度活化，加速补体降解。我们假设UMOD通过调节补体活化，降低补体活化后的炎症状态，对糖尿病肾病发生和进展有保护作用。我们使用UMOD基因敲除SD大鼠，建立1型DKD模型，通过血/尿的生化指标，肾组织病理和生物标志物变化，探讨UMOD是否在DKD的发生进展中起保护作用。通过转录组学，蛋白质表达及组织学水平的研究，探讨尿调蛋白对补体的调节在疾病模型的状态下作用的机制。体外高糖培养UMOD基因敲除和野生型的大鼠的肾小管上皮细胞及肾小管细胞系，利用重组人源性UMOD片段，初步探讨外源性UMOD片段作为治疗手段的可能性。

The abnormality of natural immunity is one of the pathogenic mechanisms of diabetic kidney disease (DKD). The local over activation caused by the abnormal regulation of complement is an important factor to induce the downstream inflammation. Renal tubular injury plays an important role in the incidence and progression of DKD. The ascending branch of the medullary loop and the beginning of the distal convoluted tubules are important areas of the renal autonomic regulation. Uromodulin (UMOD) is expressed specifically in the same area and plays a protective role in renal tubular injury. Uromodulin can inhibit over activation of complements and accelerate the degradation of C3b. Some studies have also suggested that UMOD changed in early stage of diabetic nephropathy and related to the severity of diabetes mellitus. We proposed that uromodulin can inhibit the over activation of complements in the kidney, reduce the inflammation and protect the occurrence and progress of diabetic nephropathy. In this study, we will set up diabetic nephropathy model in UMOD gene knockout SD rats to explore the protective effect of uromodulin in early diabetic nephropathy and the role of uromodulin-complement interaction in diabetic nephropathy. The main contents of this study include: 1) using diabetic nephropathy UMOD-/- SD rats to explore the role of UMOD in occurrence and progression of diabetic nephropathy, by biochemical indicators of plasma and urine and renal histopathology. 2) using animal model to study the regulatory effect of uromodulin on complement pathway on the occurrence and progress of diabetic nephropathy. The blood, urine and kidney tissue were collected at different time points after diabetes mellitus modeling. The activation of complement pathway and the activation of inflammatory factors downstream were detected by immunofluorescence, ELISA, RT-PCR and western blot and protein chip. 3) The renal tubular epithelial cells of umod knockout and wild-type SD rats were cultured in vitro with high glucose to observe complement activation and subsequent inflammatory response. The aim of this study was to explore the possibility of exogenous UMOD fragments as a therapeutic regent.