Department of Medicine IV, Tokyo Women's Medical University, Tokyo, Japan.
Nephrol Dial Transplant. 2010 Jan;25(1):60-8. doi: 10.1093/ndt/gfp451. Epub 2009 Sep 10.
High Klotho expression has been detected in the kidney, and since the results of a recent study suggested that Klotho induction mitigates ischaemic damage in the kidney, in the present study we explored the mechanism by which Klotho expression reduces renal ischaemia-reperfusion injury (IRI).
Male mice were subjected to bilateral renal ischaemia for 30 min and reperfusion for 24 h, or to a sham operation. Both the IRI group and the sham group were intravenously injected with an adenovirus harbouring the mouse Klotho gene (ad-kl) before renal IRI. In addition, mIMCD3 cells induced to overexpress Klotho by transferring the Klotho gene with ad-kl were analysed by DNA microarray and real-time PCR. Renal expression of Klotho and several genes selected by DNA microarray were assessed by real-time PCR or Western blotting, and TUNEL staining was performed to assess apoptosis.
Prior administration of ad-kl to the mice resulted in robust induction of Klotho mRNA in the kidney and liver. Ad-kl transfer improved the plasma creatinine values and mitigated the histological damage and apoptosis induced by IRI. Expression of several genes was altered in mIMCD3 cells as a result of the change in Klotho expression, and expression of heat shock protein 70 (HSP70), in particular, was up-regulated in ad-kl mouse kidneys and HK2 cells.
The results suggest that Klotho is involved in the pathophysiology of IRI. Klotho mitigates apoptosis in experimental ischaemic acute kidney injury via expression of HSP70.
Klotho 表达已在肾脏中被检测到，且最近的一项研究结果表明 Klotho 的诱导可减轻肾脏的缺血性损伤，因此本研究旨在探索 Klotho 表达降低肾缺血再灌注损伤（IRI）的机制。
雄性小鼠接受双侧肾脏缺血 30 分钟，再灌注 24 小时，或接受假手术。在肾 IRI 前，IRI 组和假手术组均通过静脉注射携带小鼠 Klotho 基因的腺病毒（ad-kl）。此外，通过用 ad-kl 转染 Klotho 基因，使 mIMCD3 细胞过表达 Klotho，然后通过 DNA 微阵列和实时 PCR 进行分析。通过实时 PCR 或 Western blot 评估肾脏 Klotho 和 DNA 微阵列选择的几个基因的表达，并用 TUNEL 染色评估细胞凋亡。
预先向小鼠给予 ad-kl 可使肾脏和肝脏中的 Klotho mRNA 得到强烈诱导。ad-kl 转移可改善血浆肌酐值，并减轻 IRI 引起的组织学损伤和细胞凋亡。由于 Klotho 表达的改变，mIMCD3 细胞中的几个基因的表达发生了改变，特别是热休克蛋白 70（HSP70）的表达在 ad-kl 小鼠肾脏和 HK2 细胞中上调。
这些结果表明 Klotho 参与了 IRI 的病理生理学过程。Klotho 通过表达 HSP70 减轻实验性缺血性急性肾损伤中的细胞凋亡。
