Hsp27 upregulation by HIF-1 signaling offers protection against retinal ischemia in rats
Hsp27 upregulation by HIF-1 signaling offers protection against retinal ischemia in rats
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DOI：
10.1167/iovs.04-0043
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发表时间：
2005-03-01
影响因子：
4.4
通讯作者：
Crosson, CE
中科院分区：
文献类型：
--
作者：
Whitlock, NA;Agarwal, N;Crosson, CE
目的.作者实验室先前的工作表明，Hsp 27在视网膜缺血预处理（IPC）后特异性上调，这种上调作为预防视网膜缺血性损伤的关键细胞保护因子。IPC后Hsp 27上调的调控机制尚不清楚。本研究的目的是探讨IPC后Hsp 27表达上调的转录事件。COCl 2检测缺氧刺激后Hsp 27的表达。通过PCR克隆了人Hsp 27基因的启动子和第一内含子区域，并通过使用报告分析进行缺失分析。然后将体外结果应用于视网膜缺血的体内模型，以确定COCl 2是否上调rHSP 27并保护视网膜免受缺血性损伤。氯化钴上调培养的视网膜神经元中的Hsp 27。启动子-内含子报告基因检测表明，几个HIF-1结合位点是必要的CoCl 2诱导的Hsp 27基因的表达。此外，CoCl 2可上调大鼠视网膜中Hsp 27的表达，对大鼠视网膜缺血损伤具有保护作用。这些数据提供了证据表明，Hsp 27通过HIF-1活化受缺氧信号转导调节，并支持IPC的早期事件是HIF-1活化的观点。这些发现是重要的，因为这是HIF-1激活首次与IPC的保护作用和HSP 27上调相关。
PURPOSE. Previous work from the authors' laboratory has shown that Hsp27 is specifically upregulated after retinal ischemic preconditioning (IPC), and this upregulation acts as a key cytoprotective factor in preventing retinal ischemic damage. The regulatory mechanisms involved in the upregulation of Hsp27 after IPC are unknown. The purpose of this study was to explore the transcriptional events responsible for the upregulation of Hsp27 after IPC.METHODS. COCl2 was used to test for Hsp27 expression after hypoxic stimulus. The promoter and first intron regions of the human Hsp27 gene were cloned by PCR and characterized by deletion analysis by using a reporter assay. In vitro results were then applied to an in vivo model of retinal ischemia to determine whether COCl2 upregulates rHsp27 and protects the retina from ischemic injury.RESULTS. CoCl2 upregulated Hsp27 in cultured retinal neurons. Promoter-intron reporter assays using various DNA deletion constructs indicated that several HIF-1 binding sites were necessary for CoCl2-induced expression of the Hsp27 gene. Furthermore, CoCl2 upregulated Hsp27 in the rat retina and protected the rat retina from ischemic injury.CONCLUSIONS. These data provide evidence that Hsp27 is regulated by hypoxic signaling through HIF-1 activation and support the idea that an early event in IPC is the activation of HIF-1. These findings are significant, because this is the first time HIF-1 activation has been associated with the protective effects of IPC and with Hsp27 upregulation.