title: Trypanosoma cruzi disrupts myofibrillar organization and intracellular calcium levels in mouse neonatal cardiomyocytes.
abstract: 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 Ca2+ 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.
authors.affiliation: Seção de Microscopia Eletrônica do Instituto Adolfo Lutz, Av. Dr. Arnaldo, 355-01246-902, São Paulo, Brazil.
authors.forename: Noemi N
authors.initials: NN
authors.lastname: Taniwaki
authors.forename: Fabiana S
authors.initials: FS
authors.lastname: Machado
authors.forename: André R
authors.initials: AR
authors.lastname: Massensini
authors.forename: Renato A
authors.initials: RA
authors.lastname: Mortara
mesh_terms: D000185:Actinin / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000814:Aniline Compounds; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D005456:Fluorescent Dyes; D042541:Intracellular Space / Q000378:metabolism; D051379:Mice; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000469:parasitology / Q000473:pathology*; D009210:Myofibrils / Q000378:metabolism / Q000473:pathology*; D009218:Myosins / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000502:physiology*; D014966:Xanthenes
chemical_list: D000199:Actins; D000814:Aniline Compounds; D005456:Fluorescent Dyes; D014966:Xanthenes; D000185:Actinin; C059715:Fluo-3; D009218:Myosins; D002118:Calcium