Protein disulfide isomerase as a novel target for cyclopentenone prostaglandins: implications for hypoxic ischemic injury.
Protein disulfide isomerase as a novel target for cyclopentenone prostaglandins: implications for hypoxic ischemic injury.
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蛋白质二硫键异构酶作为环戊烯酮前列腺素的新靶点：对缺氧缺血性损伤的影响。
DOI：
10.1111/febs.13259
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Hickey,RobertW
中科院分区：
文献类型：
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作者：
Liu,Hao;Chen,Jie;Li,Wenjin;Rose,MarieE;Shinde,SunitaN;Balasubramani,Manimalha;Uechi,GuyT;Mutus,Bülent;Graham,StevenH;Hickey,RobertW
环氧合酶-2（考克斯-2）是缺血性脑损伤的重要因素。考克斯-2毒性的下游介质的鉴定可能允许靶向治疗的开发。特别感兴趣的是前列腺素代谢物的环戊烯酮家族。环戊烯酮类化合物是一种高活性分子，可与细胞内的巯基形成共价键。蛋白质二硫键异构酶（PDI）是缺血后变性蛋白质修复的重要分子。由于PDI具有几个硫醇，包括活性硫氧还蛋白样结构域内的硫醇，我们假设PDI是CyPG的靶标，并且PDI的CyPG结合是有害的。通过免疫沉淀和MS检测CyPG与PDI的结合。CyPG与PDI的结合降低了CyPG处理的重组PDI中的PDI酶活性，并且从CyPG或缺氧处理的神经元培养物中免疫沉淀PDI。结合的毒性作用在实验中得到证实，表明：（a）PDI的药理学抑制增加了缺氧神经元中的细胞死亡，（B）PDI过表达保护了暴露于缺氧的神经元和暴露于CyPG的SH-SY 5 Y细胞，以及（c）SH-SY 5 Y细胞中的PDI过表达减弱了蛋白质的泛素化并降低了促凋亡半胱天冬酶的活化。总之，CyPG的产生和随后的PDI结合是缺血性脑损伤的一种新的和潜在的重要机制。我们发现，CyPGs结合到PDI，环戊烯酮抑制PDI活性，和CyPG-PDI结合与增加神经元对缺氧的敏感性。有必要进行额外的研究，以确定缺血和其他神经退行性疾病中CyPG依赖性抑制PDI活性的相对作用。
Cyclooxygenase‐2 (COX‐2) is an important contributor to ischemic brain injury. Identification of the downstream mediators of COX‐2 toxicity may allow the development of targeted therapies. Of particular interest is the cyclopentenone family of prostaglandin metabolites. Cyclopentenone prostaglandins (CyPGs) are highly reactive molecules that form covalent bonds with cellular thiols. Protein disulfide isomerase (PDI) is an important molecule for the restoration of denatured proteins following ischemia. Because PDI has several thiols, including thiols within the active thioredoxin‐like domain, we hypothesized that PDI is a target of CyPGs and that CyPG binding of PDI is detrimental. CyPG–PDI binding was detectedin vitrovia immunoprecipitation and MS. CyPG–PDI binding decreased PDI enzymatic activity in recombinant PDI treated with CyPG, and PDI immunoprecipitated from neuronal culture treated with CyPG or anoxia. Toxic effects of binding were demonstrated in experiments showing that: (a) pharmacologic inhibition of PDI increased cell death in anoxic neurons, (b) PDI overexpression protected neurons exposed to anoxia and SH‐SY5Y cells exposed to CyPG, and (c) PDI overexpression in SH‐SY5Y cells attenuated ubiquitination of proteins and decreased activation of pro‐apoptotic caspases. In conclusion, CyPG production and subsequent binding of PDI is a novel and potentially important mechanism of ischemic brain injury. We show that CyPGs bind to PDI, cyclopentenones inhibit PDI activity, and CyPG–PDI binding is associated with increased neuronal susceptibility to anoxia. Additional studies are necessary to determine the relative role of CyPG‐dependent inhibition of PDI activity in ischemia and other neurodegenerative disorders.