Mast-Cell Renin and Local ANG II Formation

进行性肾脏疾病的特点是纤维化介质在肾脏中积聚。 肾小球肾炎、糖尿病肾病、肾盂肾炎和肾血管疾病加在一起 超过75%的患者需要肾移植。在这些情况下，它是慢性进行性肾纤维化。 伴随功能性肾单位的丧失，导致不可逆转的肾损伤。当肾素 血管紧张素系统(RAS)传统上被视为循环轴，越来越多的证据表明 肾内RAS活性在慢性肾脏疾病和纤维化中起重要作用。基于最近的 我们实验室报告的肥大细胞表达和释放活性肾素的证据，我们假设肾素 肥大细胞从肾组织中释放，触发肾内RAS和局部血管紧张素(Ang II) 队形。这项提议的总体目标是解决这样一个重要问题，即是否渗入桅杆 细胞和肥大细胞肾素在缺血性器官损伤和纤维化中起重要作用。使用一个模型 进行性肾纤维化(单侧输尿管梗阻(DUO))我们将研究肥大细胞肾素和 在此过程中局部Ang II的产生以及腺苷在调节肥大细胞中的作用 肾素基因表达。我们的初步结果表明：1.人和啮齿动物肾脏肥大细胞表达 活性肾素。2.肥大细胞缺陷小鼠不会发生肾纤维化。3.稳定大鼠的肥大细胞 UUO肾脏可预防肾纤维化。4.抑制肥大细胞释放肾素可减少血管收缩 在隔离和灌流的肾脏中。5.刺激腺苷A2B受体增加肥大细胞肾素基因 表情。在特定目标I中，我们将表征肥大细胞肾素的分子同一性，并检测 肥大细胞肾素和局部血管紧张素Ⅱ的形成在UUO纤维化和血管收缩中的作用。这些 实验将使用从人和啮齿动物肾脏分离的肥大细胞以及HMC-1细胞，a 人肥大细胞培养模型的建立。UUO的动物研究将在大鼠和肥大细胞中进行- C-Kit基因敲除缺陷小鼠及其同源对照。特殊目的II.将检查肥大细胞的调节 肾素的表达、合成和腺苷释放。这些实验将在隔离的人类身上进行。 肾肥大细胞和HMC-1细胞。如果我们的假设被证明是正确的，那么我们将识别出一个 改善慢性肾脏疾病肾功能的新靶点(肥大细胞肾素)。

Progressive kidney disease is characterized by the accumulation of fibrotic mediators in the kidney. Glomerulonephritis, diabetic nephropathy, pyelonephritis, and renovascular disease together account for over 75% of patients requiring renal transplants. In these conditions it is chronic progressive renal fibrosis with associated loss of functioning nephrons that results in irreversible renal injury. While the renin angiotensin system (RAS) has traditionally been viewed as a circulating axis, evidence is accumulating that an active intrarenal RAS plays an important role in chronic kidney disease and fibrosis. Based on recent evidence reported from our lab that mast cells express and release active renin, we hypothesize that renin released from mast cells infiltrating the kidney triggers intra-renal RAS and local angiotensin (ANG II) formation. The overall objective of this proposal is addressing the important issue of whether infiltrating mast cells and mast-cell renin, play a significant role in ischemic organ damage and fibrosis. Using a model of progressive renal fibrosis (unilateral ureteral obstruction (DUO)) we will study the role of mast cell renin and local ANG II production in this process as well as investigate the role of adenosine in regulating mast cell renin gene expression. Our preliminary results demonstrate: 1. Human and rodent kidney mast cells express active renin. 2. Mast cell deficient mice do not develop renal fibrosis with UUO 3. Stabilizing mast cells in rat UUO kidney prevents renal fibrosis. 4. Inhibiting the renin released from mast cells reduces vasoconstriction in isolated and perfused kidney. 5. Stimulating the adenosine A2b receptor increases mast cell renin gene expression. In Specific Aim I. we will characterize the molecular identity of mast cell renin and examine the effects of mast cell renin and local ANG II formation on fibrosis and vasoconstriction in UUO. These experiments will be done with mast cells isolated from human and rodent kidney and with HMC-1 cells, a cultured cell model of human mast cells. The UUO animal studies will be carried out in rat and mast cell- deficient c-Kit knockout mice and their congenic controls. Specific Aim II. will examine regulation of mast cell renin expression, synthesis, and release by adenosine. These experiments will be done with isolated human kidney mast cells and with HMC-1 cells. If our hypothesis is proven correct then we will have identified a novel therapeutic target (mast cell renin) for ameliorating renal function in chronic kidney disease.