Bowling N, Walsh R A, Song G, Estridge T, Sandusky G E, Fouts R L, Mintze K, Pickard T, Roden R, Bristow M R, Sabbah H N, Mizrahi J L, Gromo G, King G L, Vlahos C J
Cardiovascular Research, Eli Lilly and Co, Indianapolis, Ind 46285-0520, USA.
Circulation. 1999 Jan 26;99(3):384-91. doi: 10.1161/01.cir.99.3.384.
Increased expression of Ca2+-sensitive protein kinase C (PKC) isoforms may be important markers of heart failure. Our aim was to determine the relative expression of PKC-beta1, -beta2, and -alpha in failed and nonfailed myocardium.
Explanted hearts of patients in whom dilated cardiomyopathy or ischemic cardiomyopathy was diagnosed were examined for PKC isoform content by Western blot, immunohistochemistry, enzymatic activity, and in situ hybridization and compared with nonfailed left ventricle. Quantitative immunoblotting revealed significant increases of >40% in PKC-beta1 (P<0.05) and -beta2 (P<0.04) membrane expression in failed hearts compared with nonfailed; PKC-alpha expression was significantly elevated by 70% in membrane fractions (P<0.03). PKC-epsilon expression was not significantly changed. In failed left ventricle, PKC-beta1 and -beta2 immunostaining was intense throughout myocytes, compared with slight, scattered staining in nonfailed myocytes. PKC-alpha immunostaining was also more evident in cardiomyocytes from failed hearts with staining primarily localized to intercalated disks. In situ hybridization revealed increased PKC-beta1 and -beta2 mRNA expression in cardiomyocytes of failed heart tissue. PKC activity was significantly increased in membrane fractions from failed hearts compared with nonfailed (1021+/-189 versus 261+/-89 pmol. mg-1. min-1, P<0.01). LY333531, a selective PKC-beta inhibitor, significantly decreased PKC activity in membrane fractions from failed hearts by 209 pmol. min-1. mg-1 (versus 42.5 pmol. min-1. mg-1 in nonfailed, P<0.04), indicating a greater contribution of PKC-beta to total PKC activity in failed hearts.
In failed human heart, PKC-beta1 and -beta2 expression and contribution to total PKC activity are significantly increased. This may signal a role for Ca2+-sensitive PKC isoforms in cardiac mechanisms involved in heart failure.
钙敏感蛋白激酶C（PKC）亚型的表达增加可能是心力衰竭的重要标志物。我们的目的是确定PKC-β1、-β2和-α在衰竭心肌和非衰竭心肌中的相对表达。
对诊断为扩张型心肌病或缺血性心肌病患者的离体心脏，通过蛋白质印迹法、免疫组织化学、酶活性检测和原位杂交检测PKC亚型含量，并与非衰竭左心室进行比较。定量免疫印迹显示，与非衰竭心脏相比，衰竭心脏中PKC-β1（P<0.05）和-β2（P<0.04）膜表达显著增加>40%；膜组分中PKC-α表达显著升高70%（P<0.03）。PKC-ε表达无显著变化。在衰竭的左心室中，PKC-β1和-β2免疫染色在整个心肌细胞中强烈，而非衰竭心肌细胞中染色轻微且分散。PKC-α免疫染色在衰竭心脏的心肌细胞中也更明显，染色主要定位于闰盘。原位杂交显示衰竭心脏组织心肌细胞中PKC-β1和-β2 mRNA表达增加。与非衰竭心脏相比，衰竭心脏膜组分中的PKC活性显著增加（1021±189对261±89 pmol·mg-1·min-1，P<0.01）。LY333531，一种选择性PKC-β抑制剂，使衰竭心脏膜组分中的PKC活性显著降低209 pmol·min-1·mg-1（与非衰竭心脏中的42.5 pmol·min-1·mg-1相比，P<0.04），表明PKC-β对衰竭心脏中总PKC活性的贡献更大。
在衰竭的人类心脏中，PKC-β1和-β2的表达以及对总PKC活性的贡献显著增加。这可能表明钙敏感PKC亚型在参与心力衰竭的心脏机制中起作用。
