Expression of secreted frizzled related proteins 3 and 4 in human ventricular myocardium correlates with apoptosis related gene expression
Expression of secreted frizzled related proteins 3 and 4 in human ventricular myocardium correlates with apoptosis related gene expression
复制标题
DOI：
10.1016/s0008-6363(99)00376-4
复制
发表时间：
2000-02-01
影响因子：
10.8
通讯作者：
Hatzfeld, M
中科院分区：
文献类型：
--
作者：
Schumann, H;Holtz, J;Hatzfeld, M
目的：超负荷心力衰竭与机制不明的心肌细胞凋亡有关。WNT基因编码分泌的信号分子，与卷曲的受体结合，稳定胞浆中的β-连环蛋白，转位到细胞核内，作为转录激活因子，赋予抗凋亡表型。这一信号通路被分泌的卷曲相关蛋白(SFRP)所拮抗，sFRP在细胞培养模型中调节细胞凋亡的敏感性。基于这些考虑，本研究比较了不衰竭和衰竭心脏组织样本中sFRPs的心肌基因表达和可溶性β-连环素水平。方法：本研究使用来自衰竭左心室和非衰竭供心的非缺血型跨室壁标本。用定量逆转录聚合酶链式反应(RT-PCR)检测Wnt拮抗剂SFRP1-4的mRNA浓度。用原位RT-PCR方法检测心肌组织中SFRP3、4的表达。通过蛋白质抽提物的蛋白质印迹分析，对可溶性β-连环素库进行定量。结果：与供心相比，衰竭心中促凋亡基因sFRP3和sFRP4的mRNA表达水平升高，而sFRP1和2的基因表达水平无明显变化。SFRP3和sFRP4在心肌细胞中的表达与Fas/Fas拮抗剂比值的表达呈正相关，而与抗凋亡的bclx的表达水平呈负相关(L)。在SFRP3和4高表达的心肌标本中，0.1%Triton可溶性β-连环素池的大小有减小的趋势。结论：研究结果支持这样的假设，即在衰竭的人类心肌中，Wnt/β-catenin途径通过两种内源性Wnt-拮抗剂的表达增强而减弱。这可能与超负荷的人心肌细胞的凋亡易感性表型有关。(C)2000 Elsevier Science B.V.保留所有权利。
Objective: Overload-induced heart failure is associated with myocyte apoptosis induced by unknown mechanisms. Wnt genes encode secreted signaling molecules that bind to frizzled receptors and stabilize cytosolic beta-catenin which is translocated into the nucleus, acts as transcriptional activator and imparts an apoptosis resistant phenotype. This signaling pathway is antagonized by secreted frizzled related proteins (sFRPs) which modulate apoptosis susceptibility in cell culture models. On the basis of these considerations, the present investigation compares myocardial mRNA expression of sFRPs and the level of soluble beta-catenin in tissue samples from nonfailing and failing hearts. Methods: Nonischemic transmural samples from human failing left ventricles and from nonfailing donor ventricles were used in the present study. The mRNA concentration of the Wnt-antagonists sFRP 1-4 were determined by quantitative reverse transcription polymerase chain reaction (RT-PCR). The myocardial localization of sFRP 3 and 4 expression was investigated using in situ RT-PCR. The pool of soluble beta-catenin was quantified by Western blot analysis of protein extracts. Results: The mRNA levels of proapoptotic sFRPs 3 and 4 but not of sFRP 1 and 2 were elevated in failing ventricles compared to donor hearts. There was no significant difference between patients suffering from a dilated cardiomyopathy or a coronary heart disease, sFRPs 3 and 4 were expressed in cardiomyocytes and their expression correlated with the mRNA expression of the proapoptotic Fas/Fas-antagonist ratio, but inversely with the mRNA levels of the antiapoptotic bcl-x(L). The size of the pool of 0.1% Triton soluble beta-catenin tended to decrease in myocardial samples with high sFRP 3 and 4 expression levels. Conclusions: The results support the hypothesis that in failing human myocardium the Wnt/beta-catenin pathway is attenuated by enhanced expression of two endogenous Wnt-antagonists. This might contribute to an apoptosis susceptible phenotype of overloaded human myocardium. (C) 2000 Elsevier Science B.V. All rights reserved.