Melo Tatiana G, Adesse Daniel, Meirelles Maria de Nazareth, Pereira Mirian Claudia S
Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Ultraestrutura Celular, Rio de Janeiro, RJ, Brasil.
Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Biologia Estrutural, Rio de Janeiro, RJ, Brasil.
Mem Inst Oswaldo Cruz. 2019;114:e180593. doi: 10.1590/0074-02760180593. Epub 2019 Aug 15.
Cardiac physiology depends on coupling and electrical and mechanical coordination through the intercalated disc. Focal adhesions offer mechanical support and signal transduction events during heart contraction-relaxation processes. Talin links integrins to the actin cytoskeleton and serves as a scaffold for the recruitment of other proteins, such as paxillin in focal adhesion formation and regulation. Chagasic cardiomyopathy is caused by infection by Trypanosoma cruzi and is a debilitating condition comprising extensive fibrosis, inflammation, cardiac hypertrophy and electrical alterations that culminate in heart failure.
Since mechanotransduction coordinates heart function, we evaluated the underlying mechanism implicated in the mechanical changes, focusing especially in mechanosensitive proteins and related signalling pathways during infection of cardiac cells by T. cruzi.
We investigated the effect of T. cruzi infection on the expression and distribution of talin/paxillin and associated proteins in mouse cardiomyocytes in vitro by western blotting, immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR).
Talin and paxillin spatial distribution in T. cruzi-infected cardiomyocytes in vitro were altered associated with a downregulation of these proteins and mRNAs levels at 72 h post-infection (hpi). Additionally, we observed an increase in the activation of the focal adhesion kinase (FAK) concomitant with increase in β-1-integrin at 24 hpi. Finally, we detected a decrease in the activation of FAK at 72 hpi in T. cruzi-infected cultures.
The results suggest that these changes may contribute to the mechanotransduction disturbance evidenced in chagasic cardiomyopathy.
心脏生理学依赖于通过闰盘进行的耦联以及电和机械协调。粘着斑在心脏收缩 - 舒张过程中提供机械支持和信号转导事件。踝蛋白将整合素与肌动蛋白细胞骨架连接起来，并作为募集其他蛋白质的支架，例如在粘着斑形成和调节过程中的桩蛋白。恰加斯心肌病由克氏锥虫感染引起，是一种使人衰弱的病症，包括广泛的纤维化、炎症、心脏肥大和电改变，最终导致心力衰竭。
由于机械转导协调心脏功能，我们评估了与机械变化相关的潜在机制，特别关注克氏锥虫感染心脏细胞期间的机械敏感蛋白和相关信号通路。
我们通过蛋白质印迹法、免疫荧光法和定量实时聚合酶链反应（qRT-PCR）研究了克氏锥虫感染对体外培养的小鼠心肌细胞中踝蛋白/桩蛋白及相关蛋白的表达和分布的影响。
体外培养的受克氏锥虫感染的心肌细胞中，踝蛋白和桩蛋白的空间分布发生改变，且在感染后72小时（hpi）这些蛋白和mRNA水平下调。此外，我们观察到在感染后24小时，粘着斑激酶（FAK）的激活增加，同时β-1-整合素增加。最后，我们检测到在克氏锥虫感染的培养物中，感染后72小时FAK的激活减少。
结果表明这些变化可能导致恰加斯心肌病中出现的机械转导紊乱。
