Loss of N-cadherin and α-catenin in the proximal tubules of aging male Fischer 344 rats
Loss of N-cadherin and α-catenin in the proximal tubules of aging male Fischer 344 rats
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DOI：
10.1016/j.mad.2004.04.001
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发表时间：
2004-06-01
影响因子：
5.3
通讯作者：
Parrish, AR
中科院分区：
文献类型：
--
作者：
Jung, KY;Dean, D;Parrish, AR
衰老与肾储备的丧失以及对生物外源性或生理性损伤的敏感性增加有关。鉴于钙粘蛋白/连环蛋白复合物在建立和维持肾小管上皮细胞的完整性和极性中的关键作用，假设衰老与肾钙粘蛋白/连环蛋白复合物的改变相关。从雄性Fischer 344大鼠采集的老化（24个月）肾脏的组织学评估显示近端小管轻度变性、多灶性慢性淋巴细胞浸润、小管内蛋白管型中度发展以及肾小管扩张或变性。蛋白质印迹分析显示，N-钙粘蛋白的蛋白质表达是不恒定的超过24个月。N-钙粘蛋白表达从4个月到9个月增加，在9个月和13个月达到峰值水平。在19个月时观察到表达减少，在24个月时观察到几乎完全丧失表达。相反，E-和Ksp-钙粘蛋白的表达在24个月内是恒定的。在19个月和24个月时观察到α-连环蛋白的丢失，而β-，γ-和p120-连环蛋白没有变化。通过实时PCR分析证实了这种N-钙粘蛋白表达模式（先增加后减少），该分析显示了与Western印迹相似的模式，表明N-钙粘蛋白的丢失是由于基因表达减少。N-钙粘蛋白的损失是特定的肾脏，因为在衰老过程中，在肝脏，大脑或睾丸中的N-钙粘蛋白表达没有变化。N-钙粘蛋白表达的丧失是与衰老相关的肾功能障碍的关键组成部分的结论得到以下发现的支持：热量限制减弱了N-钙粘蛋白的丧失，以及在ZDF x SHHF大鼠的肾脏中观察到N-钙粘蛋白的显著丧失。终末期肾病的遗传模型通过免疫荧光法进一步分析钙粘蛋白和连环蛋白的表达。在24个月时，在大鼠近端小管中观察到N-钙粘蛋白和α-连环蛋白染色的显著损失。有趣的是，这与Na+K+-ATP酶α-1亚基的离域相对应，即细胞-细胞边界上的异常染色和近端小管中顶端染色的一些指示。综上所述，这些数据表明，衰老与N-钙粘蛋白和α-连环蛋白的表达减少有关，并与细胞极性丧失有关。(C)2004爱思唯尔爱尔兰有限公司保留所有权利。
Aging is associated with a loss of renal reserve, and increased sensitivity to either xenobiotic or physiologic insult. Given the critical role of the cadherin/catenin complex in establishing and maintaining the integrity and polarity of tubular epithelial cells, it was hypothesized that aging was associated with alterations in renal cadherin/catenin complexes. Histological assessment of aged (24 months) kidneys harvested from male Fischer 344 rats demonstrates mild degeneration of proximal tubules, multifocal chronic lymphocytic infiltration, moderate development of protein casts inside tubules, and tubular dilatation or degeneration. Western blot analysis revealed that N-cadherin protein expression is not constant over 24 months. N-cadherin expression increased from 4 to 9 months, with peak levels at 9 and 13 months. A decrease in expression was seen at 19 months and an almost complete loss of expression was seen at 24 months. In contrast, the expression of E- and Ksp-cadherin was constant over 24 months. A loss of alpha-catenin at was seen at 19 and 24 months in the absence of changes in beta-, gamma-, and p120-catenin. This pattern of N-cadherin expression (increase followed by decrease) was confirmed by real-time PCR analysis, which demonstrated a similar pattern as the Western blot, suggesting that the loss of N-cadherin protein was due to decreased gene expression. The loss of N-cadherin was specific for the kidney, as no changes in N-cadherin expression in the liver, brain, or testes were seen during aging. The conclusion that loss of N-cadherin expression is a critical component of the renal dysfunction associated with aging is supported by the finding that caloric restriction attenuates the loss of N-cadherin, as well as the finding that a significant loss of N-cadherin is seen in the kidneys of ZDF x SHHF rats. a genetic model of end-stage renal disease. Cadherin and catenin expression was further analyzed by immunofluorescence. A significant loss of staining of both N-cadherin and alpha-catenin was seen in the proximal tubules of rats at 24 months. Interestingly, this corresponded with delocalization of the alpha-1 subunit of the Na+K+-ATPase, i.e. aberrant staining on cell-cell borders and some indication of apical staining in proximal tubules. Taken together, these data suggest that aging is associated with decreased expression of N-cadherin and alpha-catenin and is associated with a loss of cell polarity. (C) 2004 Elsevier Ireland Ltd. All rights reserved.