Kohda Y, Yamashima T, Sakuda K, Yamashita J, Ueno T, Kominami E, Yoshioka T
Department of Neurosurgery, Kanazawa University School of Medicine, Japan.
Biochem Biophys Res Commun. 1996 Nov 12;228(2):616-22. doi: 10.1006/bbrc.1996.1706.
Enzymatic activities, expressions, and the immunohistochemical localization of lysosomal cystein proteases, cathepsins B and L, were analyzed in the monkey hippocampus after transient ischemia to clarify the mechanism of delayed cornu Ammonis (CA)-1 neuronal death. By enzymatic assay, the activity of cathepsin B increased in CA-1, 24 h after the ischemic insult, while that of cathepsin L decreased. On Western blotting, the protein contents of both cathepsins B and L increased immediately after ischemia. By immunohistochemistry, cathepsins B and L were stained as coarse granules in the perikarya of control CA-1 neurons, but in postischemic CA-1 neurons they were released from lysosome granules. In contrast, in CA-2 and the remaining sectors, enzymatic activities increased after ischemia, and immunoreactivities of cathepsins B and L increased only within lysosome granules. These results suggest that cathepsins B and L may play an important role in the breakdown of certain cell proteins in the postischemic CA-1 neurons.
为阐明海马角（CA）-1区神经元延迟性死亡的机制，对短暂性脑缺血后的猴海马组织中溶酶体半胱氨酸蛋白酶组织蛋白酶B和L的酶活性、表达及免疫组化定位进行了分析。通过酶活性测定，在缺血损伤后24小时，CA-1区组织蛋白酶B的活性增加，而组织蛋白酶L的活性降低。蛋白质免疫印迹分析显示，缺血后组织蛋白酶B和L的蛋白质含量立即增加。免疫组化结果显示，在对照CA-1神经元的胞体中，组织蛋白酶B和L被染成粗大颗粒，但在缺血后的CA-1神经元中，它们从溶酶体颗粒中释放出来。相比之下，在CA-2区和其余区域，缺血后酶活性增加，组织蛋白酶B和L的免疫反应性仅在溶酶体颗粒内增加。这些结果表明，组织蛋白酶B和L可能在缺血后CA-1神经元中某些细胞蛋白的降解中起重要作用。
