GENETICS OF GLOMERULAR DISEASE IN MICE

多方面的证据表明， 肾小球硬化症在人类是遗传控制。Os突变 导致先天性肾单位数量减少50%， 肾小球肥大和标记指数增加。 这种突变 诱导肾小球硬化症（GS）的易感品系（ROP小鼠），但 不在GS耐药（C57小鼠）品系中（J Clin Invest 1996，97：1-8）。 本研究的目的是确定肾单位减少是否 在易感小鼠中诱导GS，以及是否进一步 肾单位质量的减少（75%）将在抗性菌株中诱导GS。 成年ROP +/+、ROP Os/+、C57 +/+和C57 Os/+小鼠接受单侧 肾切除术（NX）。 肾小球体积增加两周后， 在ROP +/+、C57 +/+和ROP Os/+小鼠中进行肾切除，但在C57 Os/+小鼠中不进行肾切除。 ROP +/+ NX和C57 +/+ NX小鼠肾小球标记指数增加。 而C57 +/+ NX和C57 Os/+ NX小鼠未显示肾小球变化， ROP +/+ NX小鼠表现出轻度病变，ROP Os/+ NX具有重度GS。 ROP +/+ NX组肾小球1 IV型胶原mRNA表达高于C57 +/+组 NX。 1 IV胶原、层粘连蛋白1和腱生蛋白肾小球mRNA增加 在ROP/Os而不是C57 Os/+小鼠中，肾切除后2个月。 因此 对成人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 +/+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是关键， 即使在一种情况下， 敏感菌株 为了进一步确定 我们鉴定了一种小鼠品系， 没有发展成肾小球硬化症（C3 H），并将其与 携带Os突变的硬化倾向小鼠（ROP）品系。 的 突变被用来加速，或使更明显的趋势， 发展成硬化症 F1代动物与ROP背景的回交 结果显示，F2代小鼠具有不同程度的 肾小球硬化症在3个月的年龄。 因此，我们可以证明 有一个明确的遗传易感性发展 小鼠肾小球硬化症。 这次调查的下一步 试图定位和表征某些基因座， 这是那些病变最严重的小鼠所特有的。 以来 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 8号染色体中心的标记 基于所述数个 这些动物已经回交了几代，因为突变是 在1952年，我们发现了一个很小的区域。 令人惊奇的是， 我们的定位数据显示， 长度为10厘米。 通过随后的G显带分析和荧光 在原位杂交中，我们发现，无论是大的倒位， 染色体的这一部分似乎存在大的缺失。 我们 现在必须考虑的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 是肾损伤的潜在来源，我们描述了肾 诱导脂质异常小鼠的表型。 我们选择了学习 LCAT转基因小鼠和Apo E敲除小鼠。 上 抗硬化背景，我们发现LCAT小鼠具有脂质 肾小球内皮细胞和系膜细胞中的包涵体，但 只是轻微的硬化 在载脂蛋白E中也有类似的发现。 ko老鼠。 我们现在把这些异常情况转移到一个容易硬化的 鼠标背景

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.