Differential expression of protein kinase C isoforms in streptozotocin-induced diabetic rats
Differential expression of protein kinase C isoforms in streptozotocin-induced diabetic rats
复制标题
DOI：
10.1046/j.1523-1755.1999.00725.x
复制
发表时间：
1999-11-01
影响因子：
19.6
通讯作者：
Haller, H
中科院分区：
文献类型：
--
作者：
Kang, NL;Alexander, G;Haller, H
背景高血糖的细胞效应是由蛋白激酶C（PKC）介导的。然而，体育; C由几种不同的亚型组成，它们在不同器官中对糖尿病并发症发病机制的作用尚不清楚。我们研究了糖尿病大鼠肾脏、心脏和主动脉中PKC亚型α、β I、β II、δ、β 2和ζ的表达和转位。用链脲佐菌素（70 mg/kg）诱导大鼠高血压。4周后，通过组织分离后的蛋白质印迹法和免疫组织化学法评估PKC亚型的表达。链脲佐菌素使血糖从117.0 +/- 3.6增加到510.0 +/- 19.4 mg/dl（N = 8，P < 0.01）并诱导蛋白尿。PKC亚型α、β I、β II、δ、β I和ζ均在对照动物中检测到。Westernblot结果显示，肾脏和心脏中PKC α表达增加（分别为160%和170%）。PKC β I、β III和δ表达不受高血糖的影响。糖尿病动物两种组织中PE; C5均降低60%。PKC α和PKC β的膜结合增加;然而，颗粒部分中PKC的相对量不受高血糖的影响。免疫组化显示，在肾小球和间质毛细血管，心脏毛细血管，骨骼肌，以及在大动脉的内皮细胞中的PKC α免疫反应性显着增加。PKC β在肾小球中表现出小幅下降。糖尿病大鼠肾小管PKC β表达增加，心肌PKC β表达减少。PKC zeta在心肌和肾小球细胞中均有表达，但在高血糖时表达下降。我们的研究结果表明，PKC亚型在糖尿病肾脏和心脏的差异调节。高糖增加PKC α表达，而PKC ζ下调。PKC α主要在内皮细胞中增加的发现支持了PKC α在糖尿病中观察到的功能性内皮障碍中的作用。
Background. The cellular effects of hyperglycemia are mediated by protein kinase C (PKC). However, PE;C consists of several distinct isoforms, and their contribution to the pathogenesis of diabetic complications in different organs is not clear. We investigated the expression and translocation of PKC isoforms alpha, beta I, beta II, delta, epsilon, and zeta in kidney, heart, and aorta from diabetic rats.Methods. Hyperglycemia was induced with streptozotocin (70 mg/kg) in the rat. After four weeks, PKC isoform expression was assessed by Western blot after tissue fractionation and by immunohistochemistry.Results. Streptozotocin increased blood glucose from 117.0 +/- 3.6 to 510.0 +/- 19.4 mg/dl (N = 8, P < 0.01) and induced albuminuria. PKC isoforms alpha, beta I, beta II, delta, epsilon, and zeta were all detected in control animals. Western blot showed increased PKC a expression in kidney and heart (160% and 170%, respectively). PKC beta I, beta III and delta expression was not influenced by hyperglycemia. PE;C 5 was decreased in diabetic animals in both tissues by 60%. The membrane association of PKC alpha and PKC epsilon was increased; however, the relative amount of PKC in the particulate fraction was not influenced by hyperglycemia. Immunohistochemistry revealed a marked increase in PKC alpha immunoreactivity in renal glomeruli and interstitial capillaries, cardiac capillaries, and skeletal muscle, as well as in the endothelial cells of larger arteries. PKC beta showed a small decrease in the glomeruli. PKC epsilon was increased in renal tubules in diabetic rats but was decreased in the myocardium. PKC zeta was expressed in both myocardial and glomerular cells but was decreased during hyperglycemia. Our results demonstrate that PKC isoforms are differentially regulated in kidney and heart in diabetes. High glucose increases PKC alpha expression, whereas PKC zeta is down-regulated. The finding that PKC alpha is mostly increased in endothelial cells supports a role for PKC alpha in functional endothelial disturbances observed in diabetes.