Protein kinase C upregulates intercellular adhesion molecule-1 and leukocyte-endothelium interactions in hyperglycemia via activation of endothelial expressed calpain.
Protein kinase C upregulates intercellular adhesion molecule-1 and leukocyte-endothelium interactions in hyperglycemia via activation of endothelial expressed calpain.
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DOI：
10.1161/atvbaha.110.217901
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发表时间：
2011-02
期刊：
影响因子：
--
通讯作者：
Scalia R
中科院分区：
文献类型：
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作者：
Smolock AR;Mishra G;Eguchi K;Eguchi S;Scalia R
我们检验了钙依赖性蛋白酶calpain在高血糖激活蛋白激酶C （PKC）诱导的内皮功能障碍中的作用。链脲佐菌素诱导大鼠慢性高血糖并胰岛素缺乏（1型糖尿病）。在血管组织匀浆中，分别用酶法和western blot法测定总PKC和calpain活性，以及两种内皮表达的calpain亚型µ-和m-calpain的活性和表达水平。使用活体显微镜测量微循环中白细胞-内皮细胞相互作用与钙蛋白酶活性之间的关系。采用western blot和免疫荧光法分别研究炎症粘附分子ICAM-1的表达水平和内皮定位。我们还研究了高血糖在pkc诱导的钙蛋白酶激活和作用过程中的作用机制。我们发现，在1型糖尿病血管中，PKC选择性上调微钙蛋白酶异构体的活性。机制研究证实了高血糖和PKCβ在这一过程中的作用。pkc诱导的钙蛋白酶激活的功能含义是上调内皮细胞表达的ICAM-1和白细胞-内皮相互作用。我们的研究结果揭示了微钙蛋白酶在PKC内皮功能障碍中的作用。钙蛋白酶可能是治疗pkc相关糖尿病血管疾病的一个新的分子靶点。
We tested the hypothesis of a role for the calcium-dependent protease calpain in the endothelial dysfunction induced by hyperglycemic activation of protein kinase C (PKC). Chronic hyperglycemia with insulin deficiency (Type-1 diabetes) was induced in rats by streptozotocin. Total PKC and calpain activities, along with activity and expression level of the two endothelial-expressed calpains isoforms, µ- and m-calpain, were measured in vascular tissue homogenates by enzymatic assays and western blot analysis, respectively. Intravital microscopy was used to measure and correlate leukocyte-endothelium interactions with calpain activity in the microcirculation. Expression levels and endothelial localization of the inflammatory adhesion molecule ICAM-1 were studied by western blot analysis and immunofluorescence, respectively. The mechanistic role of hyperglycemia alone in the process of PKC-induced calpain activation and actions was also investigated. We found that in the Type-1 diabetic vasculature PKC selectively upregulates the activity of the µ-calpain isoform. Mechanistic studies confirmed a role for hyperglycemia and PKCβ in this process. The functional implications of PKC-induced calpain activation were upregulation of endothelial expressed ICAM-1 and leukocyte-endothelium interactions. Our results uncover the role of µ-calpain in the endothelial dysfunction of PKC. Calpain may represent a novel molecular target for the treatment of PKC-associated diabetic vascular disease.