Trypanosoma cruzi disrupts myofibrillar organization and intracellular calcium levels in mouse neonatal cardiomyocytes

Immunofluorescence studies of normal and Trypanosoma cruzi-infected primary cultures of heart muscle cells were performed to gather information about the arrangement of myofibrillar components during the intracellular life cycle of this parasite. By using a panel of monoclonal antibodies against various myofibrillar proteins, a progressive disruption and loss of contractile proteins (such myosin and actin) of the host cell was detected during infection. the host cell formed a loose network of myofibrillar proteins around the parasites. Breakdown of the myofibrils occurred in regions where the parasites were present, and heavily infected cells showed myofibrillar proteins at their periphery. in parallel, we investigated the effect of T. cruzi infection on intracellular calcium levels by using a Ca(2+) fluorescent indicator (confocal microscopy). Infected cardiomyocytes displayed a marked impairment in contractility, and calcium influxes became irregular and less intense when compared with those of non-infected cells. Our results demonstrate that T. cruzi infection dramatically affects calcium fluxes and causes myofibrillar breakdown disturbing cardiomyocyte contractility.Universidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, Escola Paulista Med, BR-04023062 São Paulo, BrazilInst Adolofo Lutz, Secao Microscopia Eletron, BR-01246902 São Paulo, BrazilUSP, Dept Imunol & Farmacol, Fac Med, Ribeirao Preto, SP, BrazilUniv Fed Minas Gerais, Inst Ciencias Biol, Dept Fisiol & Biofis, Belo Horizonte, MG, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, Escola Paulista Med, BR-04023062 São Paulo, BrazilWeb of Scienc