Xu Min, Yang Lei, Rong Jia-Guo, Ni Yong, Gu Wei-Wei, Luo Yu, Ishidoh Kazumi, Katunuma Nobuhiko, Li Zhong-Sheng, Zhang Hui-Ling
Department of Pharmacology and Laboratory of Cerebrovascular Pharmacology, College of Pharmaceutical Science, Soochow University, Suzhou, 215123, China.
Glia. 2014 Jun;62(6):855-80. doi: 10.1002/glia.22645. Epub 2014 Feb 24.
The roles of cathepsins in the ischemic astrocytic injury remain unclear. Here, we test the hypothesis that activation of cathepsin B and L contributes to the ischemic astrocyte injury via the tBid-mitochondrial apoptotic signaling pathways. In the rat models of pMCAO, CA-074Me or Clik148, a selective inhibitor of cathepsin B or cathepsin L, reduced the infarct volume, improved the neurological deficits and increased the MAP2 and GFAP levels. In OGD-induced astrocyte injury, CA-074Me or Clik148 decreased the LDH leakage and increased the GFAP levels. In the ischemic cortex or OGD-induced astrocytes injury, Clik148 or CA-074Me reversed pMCAO or OGD-induced increase in active cathepsin L or cathepsin B at 3 h or 6 h, increase in tBid, reduction in mitochondrial cytochrome-c (Cyt-c) and increase in cytoplastic Cyt-c and active caspase-3 at 12-24 h of the late stage of pMCAO or OGD. CA-074Me or Clik148 also reduced cytosolic and mitochondrial tBid, increased mitochondrial Cyt-c and decreased cytoplastic Cyt-c and active caspase-3 at 6 h of the early stage of Bid activation. CA-074Me or Clik148 blocked the pMCAO-induced release of cathepsin B or L from the lysosomes into the cytoplasm and activation of caspase-3 in ischemic astrocytes at 12 h after ischemia. Concurrent inhibition of cathepsin B and cathepsin L provided better protection on the OGD-induced astrocytic apoptosis than obtained with separate use of each inhibitor. These results suggest that inhibition of the cysteine cathepsin B and cathepsin L activation in ischemic astrocytes contributes to neuroprotection via blocking the tBid-mitochondrial apoptotic signaling pathway.
组织蛋白酶在缺血性星形胶质细胞损伤中的作用仍不清楚。在此，我们检验了以下假设：组织蛋白酶B和L的激活通过tBid-线粒体凋亡信号通路导致缺血性星形胶质细胞损伤。在大脑中动脉永久性闭塞（pMCAO）大鼠模型中，组织蛋白酶B的选择性抑制剂CA-074Me或组织蛋白酶L的选择性抑制剂Clik148可减小梗死体积、改善神经功能缺损并提高微管相关蛋白2（MAP2）和胶质纤维酸性蛋白（GFAP）水平。在氧糖剥夺（OGD）诱导的星形胶质细胞损伤中，CA-074Me或Clik148可减少乳酸脱氢酶（LDH）泄漏并提高GFAP水平。在缺血皮层或OGD诱导的星形胶质细胞损伤中，Clik148或CA-074Me可逆转pMCAO或OGD在3小时或6小时时诱导的活性组织蛋白酶L或组织蛋白酶B增加、tBid增加、线粒体细胞色素c（Cyt-c）减少以及在pMCAO或OGD后期12至24小时时细胞质Cyt-c和活性半胱天冬酶-3增加。CA-074Me或Clik148在Bid激活早期6小时时还可减少细胞质和线粒体中的tBid、增加线粒体Cyt-c并减少细胞质Cyt-c和活性半胱天冬酶-3。CA-074Me或Clik148可在缺血12小时后阻断pMCAO诱导的组织蛋白酶B或L从溶酶体释放到细胞质中以及缺血性星形胶质细胞中半胱天冬酶-3的激活。同时抑制组织蛋白酶B和组织蛋白酶L对OGD诱导的星形胶质细胞凋亡的保护作用比单独使用每种抑制剂更好。这些结果表明，抑制缺血性星形胶质细胞中半胱氨酸组织蛋白酶B和组织蛋白酶L的激活通过阻断tBid-线粒体凋亡信号通路有助于神经保护。
