Interplay between the gamma isoform of PKC and calcineurin in regulation of vulnerability to focal cerebral ischemia
Interplay between the gamma isoform of PKC and calcineurin in regulation of vulnerability to focal cerebral ischemia
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DOI：
10.1097/00004647-200002000-00016
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发表时间：
2000-02-01
影响因子：
6.3
通讯作者：
Waxham, MN
中科院分区：
文献类型：
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作者：
Aronowski, J;Grotta, JC;Waxham, MN
分别由蛋白激酶和蛋白磷酸酶介导的蛋白磷酸化和去磷酸化是影响缺血性卒中易感性的各种重要神经过程中的重要步骤。本研究利用基因敲除的突变小鼠(Gamma PKC-KO)，研究了神经元特异性蛋白激酶Cγ亚型(Gamma PKC-KO)在可逆性局灶性脑缺血中的作用。单侧大脑中动脉和颈总动脉结扎150min后再灌流21.5h后，伽马PKC-KO组的脑梗塞体积(n=10；31.1±4.2 mm(3))显著大于野生型(n=12；22.6+/-7.4 mm(3))(P<；0.005)。为了控制可能与遗传背景有关的差异，作者在局灶性脑缺血的MCA/CCA模型中分析了Balb/CJ、C57BL/6J和129SVJ WT，发现这些WT株之间的每搏出量没有显著差异。由于伽马PKC-KO导致的底物磷酸化受损，可以通过抑制蛋白质去磷酸化来纠正。为了验证这种可能性，伽马PKC-KO小鼠在缺血前接受了蛋白磷酸酶2B(钙调神经磷酸酶)抑制剂FK-506的治疗。FK506能缩小(P<；0.008)γ-PKC-KO小鼠(n=7；24.6+/-4.6 mm(3))的脑梗塞体积，但对WT小鼠(n=7；20.5+/-10.7 mm(3))的脑梗塞体积无影响。这些结果表明，γ-PKC在可逆性局灶性脑缺血中具有一定的神经保护作用。
Protein phosphorylation and dephosphorylation mediated by protein kinases and protein phosphatases, respectively, represent essential steps in a variety of vital neuronal processes that could affect susceptibility to ischemic stroke. In this study, the role of the neuron-specific gamma isoform of protein kinase C (gamma PKC) in reversible focal ischemia was examined using mutant mice in which the gene for gamma PKC was knocked-out (gamma PKC-KO). A period of 150 minutes of unilateral middle cerebral artery and common carotid artery (MCA/CCA) occlusion followed by 21.5 hours of reperfusion resulted in significantly larger (P < 0.005) infarct volumes (n = 10; 31.1 +/- 4.2 mm(3)) in gamma PKC-KO than in wild-type (WT) animals (n = 12; 22.6 +/- 7.4 mm(3)). To control for possible differences related to genetic background, the authors analyzed Balb/cJ, C57BL/6J, and 129SVJ WT in the MCA/CCA model of focal ischemia, No significant differences in stroke volume were detected between these WT strains. Impaired substrate phosphorylation as a consequence of gamma PKC-KO might be corrected by inhibition of protein dephosphorylation. To test this possibility, gamma PKC-KO mice were treated with the protein phosphatase 2B (calcineurin) inhibitor, FK-506, before ischemia. FK-506 reduced (P < 0.008) the infarct volume in gamma PKC-KO mice (n = 7; 24.6 +/- 4.6 mm(3)), but at this dose in this model, had no effect on the infarct volume in WT mice (n = 7; 20.5 +/- 10.7 mm(3)). These results indicate that gamma PKC plays some neuroprotective role in reversible focal ischemia.