Caspase activation and amyloid precursor protein cleavage in rat ocular hypertension.
Caspase activation and amyloid precursor protein cleavage in rat ocular hypertension.
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发表时间：
2002-04
影响因子：
4.4
通讯作者：
S. Mckinnon;D. Lehman;Lisa A. Kerrigan-Baumrind;C. Merges;M. Pease;Danielle F. Kerrigan;N. Ransom;N. Tahzib;H. Reitsamer;H. Levkovitch-Verbin;H. Quigley;D. Zack
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作者：
S. Mckinnon;D. Lehman;Lisa A. Kerrigan-Baumrind;C. Merges;M. Pease;Danielle F. Kerrigan;N. Ransom;N. Tahzib;H. Reitsamer;H. Levkovitch-Verbin;H. Quigley;D. Zack
青光眼视网膜神经节细胞（RGC）死亡与凋亡有关。半胱天冬酶的激活和淀粉样前体蛋白（APP）的异常加工是其他慢性神经退行性变，如阿尔茨海默病（AD）的重要事件。本研究观察了大鼠高眼压性青光眼模型视网膜中caspase-3的表达和激活，以及caspase-3介导的APP加工模式。方法通过慢性高眼压或视神经切断造成RGC死亡。通过激光凝固或角膜缘高渗盐水注射阻塞房水流出而产生IOP升高。用RNase保护试验（RPA）、免疫细胞化学、免疫印迹试验和比色试验检测视网膜中Caspase活性和APP加工。结果RPA显示caspase-3 mRNA及其他凋亡相关mRNA表达水平升高。免疫细胞化学显示，caspase-3激活的RGCs被高眼压损害。caspase-3介导的APP裂解产物（DeltaC-APP）的产生也在高眼压RGC中增加。Western免疫印迹法和比色法显示高眼压视网膜中caspase-3的活化程度显著高于对照视网膜。通过免疫组织化学在RGCs中检测到caspase-8的活化形式（一种启动剂caspase）和淀粉样蛋白-β（一种APP蛋白水解产物和AD中老年斑的组成部分），在高眼压症患者中比对照视网膜中更常见。通过Western免疫印迹分析，高眼压视网膜中全长APP的量减少，含淀粉样β蛋白的片段增加。结论慢性高眼压大鼠RGCs存在caspase激活和APP加工异常，可能参与了青光眼的病理生理过程。
PURPOSE Retinal ganglion cell (RGC) death in glaucoma involves apoptosis. Activation of caspases and abnormal processing of amyloid precursor protein (APP) are important events in other chronic neurodegenerations, such as Alzheimer's disease (AD). The retinal expression and activation of caspases and the patterns of caspase-3-mediated APP processing in ocular hypertensive models of rat glaucoma were investigated. METHODS RGC death was produced in one eye by chronic exposure to increased intraocular pressure (IOP) or by optic nerve transection. Elevated IOP was produced by obstruction of aqueous humor outflow with laser coagulation or limbal hypertonic saline injection. Caspase activity and APP processing in the retina were examined by RNase protection assay (RPA), immunocytochemistry, immunoblot assay, and colorimetric assay. RESULTS RPA revealed elevations of caspase-3 mRNA, as well as other apoptosis-related mRNAs. Immunocytochemistry showed caspase-3 activation in RGCs damaged by ocular hypertension. The generation of the caspase-3-mediated APP cleavage product (DeltaC-APP) was also increased in ocular hypertensive RGCs. Western immunoblot assay and colorimetry revealed significantly more activated caspase-3 in ocular hypertensive retinas than in control retinas. The activated form of caspase-8, an initiator caspase, and amyloid-beta, a product of APP proteolysis and a component of senile plaques in AD, were detected in RGCs by immunohistochemistry significantly more often in ocular hypertensive than in control retinas. The amounts of full-length APP were reduced and amyloid-beta-containing fragments were increased in ocular hypertensive retinas by Western immunoblot assay. CONCLUSIONS Rat RGCs subjected to chronic ocular hypertension demonstrate caspase activation and abnormal processing of APP, which may contribute to the pathophysiology of glaucoma.