Role of NG2 in diabetic nephropathy

NG2在糖尿病肾病中的作用

• 批准号: 7925530
• 负责人: Vesselina G Cooke
• 金额: $ 5.22万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-22 至 2011-09-21
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7925530
• 关键词: Applications Grants; Blood Vessels; CSPG4 gene; Cell surface; Cells; Chondroitin Sulfate Proteoglycan; Chronic Kidney Failure; Complications of Diabetes Mellitus; Diabetes Mellitus; Diabetic Nephropathy; Disease Progression; Dose; Extracellular Matrix; Ganciclovir; Glomerular Mesangial Cell; Human; Hyperglycemia; Injection of therapeutic agent; Kidney; Medicine; Mus; Nephrology; Partner in relationship; Pericytes; Phase; Prevention; Production; Proliferating; Property; Proteins; Reagent; Research Personnel; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Sorting - Cell Movement; Streptozocin; Structure; System; Thymidine Kinase; Time; Transgenic Mice; Viral; cell envelope; cell type; diabetic; glomerular basement membrane; insight; mesangial cell; migration; mouse model; novel; receptor

DESCRIPTION (provided by applicant): Diabetic nephropathy is a common complication of diabetes mellitus types 1 and 2. Prevention of chronic renal failure is one of the most important challenges in medicine for nephrologists and nephrology researchers, Diabetic nephropathy is characterized by changes in the structure of glomerular basement membranes, and progressive expansion of the mesangial matrix. Glomerular mesangial cells are considered to be modified pericyte-like cells (perivascular cells) that envelope most small and large blood vessels. NG2, a cell surface chondroitin sulfate proteoglycan is a specific marker for pericytes and specifically expresses in mesangial cells of the human and mouse kidneys when compared to other cell types of the glomeruli, Our preliminary studies suggest that NG2 expression increases in the mouse models of diabetic nephropathy. Such increase in NG2 expression directly correlates with an increased proliferation of mesangial cells and production of extracellular matrix in the glomeruli of mice with hyperglycemia induced by streptozotocin (STZ). Utilizing novel NG2 specific mouse transgenic reagents, our aim one in this grant application proposes to study the contribution of NG2 positive mesangial cells in the initiation and progression of diabetic nephropathy. Our second aim is to gain mechanistic insights into the progression of this disease by deleting TGF-¿ regulated signaling molecules in NG2 positive mesangial cells. To achieve aim one, we will induce diabetic nephropathy by multiple low dose injection of STZ in transgenic mice in which mesangial cells are transgenically tagged with yellow fluorescent protein or viral thymidine kinase (to ablate proliferating mesangial cells at specific time points using ganciclovir) and evaluate the functional contribution of NG2 to early phases of diabetic nephropathy. Additionally, NG2 positive mesangial cells from both diabetic and control mice will be isolated by FACS sorting and their proliferation, migration, and ECM deposition properties will be investigated in the culture system, TGF-¿ is a key modulator of hyperglycemia induced mesangial cells acivity in diabetic nephropathy and thus to further gain mechanistic insight into this signaling axis, in our second aim we will specifically delete TGF-¿ receptor II and its downstream intracellular signaling modulator Smad4 in NG2 positive mesangial cells. We plan to achieve this by mating NG2-Cre mice with TGF-¿ Rll floxed and Smad4 floxed mice. STZ induced diabetes in these mice will determine the contribution of TGF-¿ signaling pathway in these novel mouse models. Collectively these studies will elucidate novel mechanisms associated with early diabetic nephropathy and open new avenues to explore therapies.

描述（由申请人提供）：糖尿病肾病是1型和2型糖尿病的常见并发症。慢性肾衰竭的预防是肾脏病学家和肾脏病研究人员面临的最重要的医学挑战之一，糖尿病肾病的特点是肾小球基底膜结构的改变和肾小球系膜基质的进行性扩张。肾小球系膜细胞被认为是修饰的周细胞样细胞（血管周围细胞），包裹着大多数大小血管。NG2是一种细胞表面硫酸软骨素蛋白多糖，是周细胞的特异性标志物，与其他类型的肾小球细胞相比，NG2在人和小鼠肾脏系膜细胞中特异性表达。我们的初步研究表明，NG2在糖尿病肾病小鼠模型中的表达增加。这种NG2表达的增加与链脲佐菌素（STZ）诱导的高血糖小鼠肾小球系膜细胞增殖和细胞外基质生成的增加直接相关。利用新的NG2特异性小鼠转基因试剂，我们的目标是研究NG2阳性系膜细胞在糖尿病肾病的发生和发展中的作用。我们的第二个目标是通过删除NG2阳性系膜细胞中TGF-调控的信号分子来获得对这种疾病进展的机制见解。为了实现第一个目标，我们将在转基因小鼠中多次低剂量注射STZ诱导糖尿病肾病，其中系膜细胞被转基因标记为黄色荧光蛋白或病毒性胸苷激酶（使用更昔洛韦在特定时间点消融增殖的系膜细胞），并评估NG2在糖尿病肾病早期的功能贡献。此外，我们将通过FACS分选从糖尿病小鼠和对照组小鼠中分离出NG2阳性的系膜细胞，并在培养系统中研究其增殖、迁移和ECM沉积特性。TGF-¿是糖尿病肾病中高血糖诱导的系膜细胞活性的关键调节剂，从而进一步了解该信号轴的机制。在我们的第二个目标中，我们将特异性地删除NG2阳性系膜细胞中的TGF-¿受体II及其下游细胞内信号调节因子Smad4。我们计划通过将NG2-Cre小鼠与TGF-¿Rll和Smad4 floxed小鼠交配来实现这一目标。STZ诱导这些小鼠的糖尿病将决定TGF-¿信号通路在这些新型小鼠模型中的作用。总的来说，这些研究将阐明与早期糖尿病肾病相关的新机制，并为探索治疗开辟新的途径。