GENETICS OF GLOMERULAR DISEASE IN MICE

小鼠肾小球疾病的遗传学

• 批准号: 6161986
• 负责人: L J STRIKER
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6161986
• 关键词: animal genetic material tag; basement membrane; collagen; disease /disorder model; disease /disorder proneness /risk; extracellular matrix; gene expression; gene mutation; genetic disorder; genetic strain; glomerulosclerosis; histopathology; kidney cell; laboratory mouse; laminin; phenotype; polymerase chain reaction; renal glomerulus; renal tubule; tissue /cell culture

Multiple lines of evidence suggest that the propensity to develop glomerulosclerosis in man is under genetic control. The Os mutation induces a congenital 50% reduction in nephron number and both hypertrophy and increased labeling index in glomeruli. This mutation induced glomerulosclerosis (GS) in a susceptible strain (ROP mice), but not in a GS resistant (C57 mice) strain (J Clin Invest 1996, 97:1-8). The purposes of this study were to determine whether nephron reduction after birth induced GS in susceptible mice, and whether further reduction in nephron mass (75%) would induce GS in resistant strains. Adult ROP +/+, ROP Os/+, C57 +/+ and C57 Os/+ mice underwent unilateral nephrectomy (NX). Glomerular volume increased two weeks after nephrectomy in ROP +/+, C57 +/+ and ROP Os/+ but not in C57 Os/+ mice. Glomerular labeling index increased in ROP +/+ NX and C57 +/+ NX mice. Whereas C57 +/+ NX and C57 Os/+ NX mice showed no glomerular changes, ROP +/+ NX mice exhibited mild lesions and ROP Os/+ NX had severe GS. Glomerular 1IV collagen mRNA was higher in ROP +/+ NX than in C57 +/+ NX. 1IV collagen, laminin 1, and tenascin glomerular mRNAs increased in ROP/Os but not C57 Os/+ mice 2 months after nephrectomy. Thus, the response to adult nephron reduction depended on the mouse strain, since nephrectomy induced lesions only in ROP mice. The lesions in ROP +/+ NX were less severe than in sham operated ROP Os/+ mice, suggesting that the time at which nephron reduction occurs was critical in determining the amplitude of the sclerotic response, even in a susceptible strain. In order to further determine the nature of the genes implicated in glomerulosclerosis we identified a mouse strain that did not develop glomerulosclerosis (C3H), and crossed it with a sclerosis-prone mouse (ROP) strain carrying the Os mutation. The mutation was used to accelerate, or make more obvious, the tendency to develop sclerosis. A backcross of the F1 animals to the ROP background revealed that the resulting F2 generation mice had varying degrees of glomerulosclerosis at the age of 3 months. Thus, we could demonstrate that there was a clear-cut inheritance of the susceptibility to develop glomerulosclerosis in mice. The next steps in this investigation will be to attempt the localization and characterization of certain loci which are peculiar to those mice with the most severe lesions. Since the Os gene is of interest in renal development, we tried to localize this mutation using a PCR based mapping approach using forty SSLP markers in the center of chromosome 8. Based on the number of generations the animals have been backcrossed, since the mutation was induced in 1952, we expected to find a very small region. Surprisingly, our mapping data revealed a linkage dysequilibrium involving a region of 10 cM in length. By subsequent G-banding analysis and fluorescence in situ hybridization, we found that neither a large inversion nor a large deletion seems to be present in this part of the chromosome. We now have to consider that the defect is due to one or more smaller chromosomal abnormalities. Since lipid abnormalities are thought to be a potential source of renal injury, we characterized the renal phenotype of mice with induced lipid abnormalities. We chose to study mice transgenic for LCAT and Apo E knockout mice. On a sclerosis-resistant background we found that LCAT mice had lipid inclusions in glomerular endothelial and mesangial cells, but that there was very little sclerosis. Similar findings were present in the Apo E ko mice. We are now crossing these abnormalities onto a sclerosis-prone mouse background.

多项证据表明，发展倾向 人类肾小球硬化症受遗传控制。 Os突变 导致肾单位数量先天性减少 50% 肾小球肥大和标记指数增加。 这个突变 在易感品系（ROP 小鼠）中诱导肾小球硬化（GS），但是 GS 抗性（C57 小鼠）品系中不存在这种情况（J Clin Invest 1996, 97:1-8）。 本研究的目的是确定肾单位减少是否 出生后在易感小鼠中诱导 GS，以及是否进一步 肾单位质量减少（75%）会在耐药菌株中诱导 GS。 成年 ROP +/+、ROP Os/+、C57 +/+ 和 C57 Os/+ 小鼠接受单侧治疗 肾切除术（NX）。 两周后肾小球体积增大 ROP +/+、C57 +/+ 和 ROP Os/+ 小鼠进行肾切除术，但 C57 Os/+ 小鼠则不然。 ROP +/+ NX 和 C57 +/+ NX 小鼠的肾小球标记指数增加。 而 C57 +/+ NX 和 C57 Os/+ NX 小鼠没有表现出肾小球变化， ROP +/+ NX 小鼠表现出轻度病变，ROP Os/+ NX 小鼠表现出严重的 GS。 ROP +/+ NX 中的肾小球 1IV 胶原 mRNA 高于 C57 +/+ 中的肾小球 1IV 胶原 mRNA NX。 1IV 胶原蛋白、层粘连蛋白 1 和生腱蛋白肾小球 mRNA 增加 肾切除术后 2 个月，在 ROP/Os 小鼠中出现，但在 C57 Os/+ 小鼠中则不然。 因此， 对成年肾单位减少的反应取决于小鼠品系，因为 肾切除术仅在 ROP 小鼠中引起病变。 ROP +/+ 中的病变 NX 的严重程度低于假手术 ROP Os/+ 小鼠，表明 肾单位减少发生的时间对于 确定硬化反应的幅度，即使在 敏感菌株。 为了进一步确定该案的性质 与肾小球硬化症有关的基因我们鉴定了一种小鼠品系 没有发展成肾小球硬化症（C3H），并将其与 携带 Os 突变的硬化倾向小鼠 (ROP) 品系。 这 突变被用来加速或使这种趋势变得更加明显 发展为硬化。 F1 动物与 ROP 背景的回交 研究表明，由此产生的 F2 代小鼠具有不同程度的 3个月大时出现肾小球硬化。 因此，我们可以证明 发展的易感性具有明显的遗传性 小鼠肾小球硬化。 这项调查的下一步将 尝试对某些基因座进行定位和表征 这是那些病变最严重的小鼠所特有的。 自从 Os 基因与肾脏发育有关，我们试图定位 该突变使用基于 PCR 的作图方法，使用 40 个 SSLP 位于 8 号染色体中心的标记。基于 动物已经回交了好几代，因为突变是 1952 年，我们预计会发现一个非常小的区域。 出奇， 我们的绘图数据揭示了涉及某个区域的连锁不平衡 长度为10厘米。 通过随后的 G 带分析和荧光 原位杂交，我们发现既没有大的倒转也没有 染色体的这一部分似乎存在大的缺失。 我们 现在必须考虑该缺陷是由于一个或多个较小的 染色体异常。 由于脂质异常被认为 是肾损伤的潜在来源，我们对肾损伤进行了表征 诱导脂质异常的小鼠的表型。 我们选择了学习 LCAT 和 Apo E 基因敲除小鼠转基因小鼠。 上一个 抗硬化背景我们发现LCAT小鼠有脂质 肾小球内皮细胞和系膜细胞中的包涵体，但存在 硬化很少。 Apo E 中也有类似的发现 老鼠啊。 我们现在正在将这些异常现象转移到易发生硬化的疾病上 鼠标背景。