Hypoxia inducible factor-1alpha is increased in ischemic retina: temporal and spatial correlation with VEGF expression.
Hypoxia inducible factor-1alpha is increased in ischemic retina: temporal and spatial correlation with VEGF expression.
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发表时间：
1999
影响因子：
4.4
通讯作者：
H. Ozaki;A. Yu;N. Della;Keiko Ozaki;J. Luna;Haruhiko Yamada;S. Hackett;N. Okamoto;D. Zack;G. Semenza;P. Campochiaro
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作者：
H. Ozaki;A. Yu;N. Della;Keiko Ozaki;J. Luna;Haruhiko Yamada;S. Hackett;N. Okamoto;D. Zack;G. Semenza;P. Campochiaro
缺氧诱导因子-1（Hypoxia inducible factor-1，HIF-1）是由HIF-1 α和HIF-1 β两个亚基组成的转录因子。HIF-1反式激活多个基因，其产物在氧稳态中起关键作用，包括血管内皮生长因子（VEGF）。本研究旨在确定缺血性视网膜中HIF-1水平是否增加以及是否与VEGF表达增加相关。方法C57 BL/6 J小鼠在视网膜血管发育的时间点（PO至成年）或出生后第7天（P）将其置于75%氧环境中5d，然后移到空气中并在0、2、6、24 h和5、14 d后处死。将眼睛冷冻，分离视网膜并用于免疫印迹分析，或将眼睛切片用于HIF-1 α或HIF-1 β的免疫组织化学染色，或用于VEGF的原位杂交。结果视网膜裂解物的免疫印迹显示，在PO时HIF-1 α的水平较低，在P4时显著升高，在整个视网膜血管发育期间保持较高水平，然后在成人中降至中等水平。HIF-1 β水平在所有时间点均相对恒定。在患有氧诱导缺血性视网膜病变的小鼠中，视网膜中的HIF-1 α水平升高。增加的峰值出现在2小时，并且水平在24小时恢复到基线。免疫组化显示缺氧的内层视网膜中HIF-1 α的染色增加，但在含氧量正常的外层视网膜中没有。HIF-1 β水平无调节作用。有组成性表达的血管内皮生长因子mRNA的内核层，增加6小时后缺氧发作，并保持升高了几天。结论：缺血视网膜组织中HIF-1 α表达增加，与VEGF表达增加具有时间和空间相关性。这些发现与HIF-1在缺血性视网膜中VEGF上调中起作用的假设一致。
PURPOSE Hypoxia inducible factor-1 (HIF-1) is a transcription factor composed of HIF-1alpha and HIF-1beta subunits. HIF-1 transactivates multiple genes whose products play key roles in oxygen homeostasis, including vascular endothelial growth factor (VEGF). This study was designed to determine whether HIF-1 levels are increased in ischemic retina and whether there is a correlation with increased expression of VEGF. METHODS C57BL/6J mice were killed at time points that span retinal vascular development (PO to adult), or on postnatal day (P) 7 they were placed in a 75% oxygen environment for 5 days and then removed to room air and killed after 0, 2, or 6, or 24 hours and 5 or 14 days. Eyes were frozen, and retinas were isolated and used for immunoblot analysis, or eyes were sectioned for immunohisto chemical staining for HIF-1alpha or HIF-1beta, or for in situ hybridization for VEGF. RESULTS Immunoblots of retinal lysates showed low levels of HIF-1alpha at PO that were markedly increased at P4, remained high throughout the period of retinal vascular development and then decreased to an intermediate level in adults. HIF-1beta levels were relatively constant at all time points. In mice with oxygen-induced ischemic retinopathy, HIF-1alpha levels were increased in the retina. The peak of increase occurred at 2 hours, and levels returned to baseline by 24 hours. Immunohistochemistry showed increased staining for HIF-1alpha throughout the hypoxic inner retina, but not in the normoxic outer retina. There was no modulation of HIF-1beta levels. There was constitutive expression of VEGF mRNA in the inner nuclear layer that was increased 6 hours after the onset of hypoxia and remained elevated for several days. CONCLUSIONS There are increased levels of HIF-1alpha in ischemic retina that show temporal and spatial correlation with increased expression of VEGF. These findings are consistent with the hypothesis that HIF-1 plays a role in upregulation of VEGF in ischemic retina.