Trypanosoma cruzi–cardiomyocyte interaction: role of fibronectin in the recognition process and extracellular matrix expression in vitro and in vivo C.M. Calvet, a M. Meuser, b D. Almeida, a M.N.L. Meirelles, a and M.C.S. Pereira a, * a Laborat orio de Ultra-estrutura Celular and Departamento de Ultra-estrutura e Biologia Celular, Instituto Oswaldo Cruz/FIOCRUZ. Av. Brasil 4365, Manguinhos, Rio de Janeiro, RJ, Brazil b Laborat orio de Biologia Celular, Departamento de Ultra-estrutura e Biologia Celular, Instituto Oswaldo Cruz/FIOCRUZ. Av. Brasil 4365, Manguinhos, Rio de Janeiro, RJ, Brazil Received 8 October 2003; received in revised form 2 April 2004; accepted 5 April 2004 Available online 18 May 2004 Abstract We investigated the involvement of fibronectin (FN) in Trypanosoma cruzi–cardiomyocyte invasion and the extracellular matrix (ECM) components expression during T. cruzi infection in vivo and in vitro. Treatment of trypomastigotes with FN or a synthetic peptide (MRGDS) prior to cardiomyocyte interaction reduced T. cruzi infection, indicating that FN mediates the parasite invasion through its RGD sequence. In murine experimental Chagas’ disease, an enhancement of the ECM components was detected in the myocardium during the late acute infection, coinciding with inflammatory infiltrates accumulation. In contrast, highly infected cardiomyocytes displayed a reduction in FN expression in vitro, while laminin spatial distribution was altered. Although it has been demonstrated that cardiomyocytes are able to synthesize cytokines upon T. cruzi infection, our data suggest that matrix remodeling is dependent on cytokines secreted by inflammatory cells recruited in immune response. Ó 2004 Elsevier Inc. All rights reserved. Index Descriptors and Abbreviation: Trypanosoma cruzi; cardiomyocyte; ECM, extracellular matrix; FN, fibronectin; LN, laminin; TS, trans-sialidase; DMEM, Dulbecco’s modified Eagle’s medium; FBS, fetal bovine serum; HE, hematoxilin–eosin; huFN, human plasma fibronectin; RGD (Arg-Gly- Asp) and MRGDS (Met-Arg-Gly-Asp-Ser) sequence; PBS, phosphate-buffered saline; BSA, bovine serum albumin; DAPI, 4 0 ,6-diamidino-2- phenilyndole; DABCO, 1,4-diazabicyclo-(2.2.2)-octane; dpi, days post-infection 1. Introduction Chagas’ disease, caused by the protozoan Trypano- soma cruzi, is an important public health problem that affects several million people in endemic regions of South and Central America (WHO, 2000). The Chagasic chronic cardiomyopathy is an irreversible and incapac- itating illness and represents an economic problem in developing countries. Trypanosoma cruzi is an obliga- tory intracellular parasite that is able to invade different types of mammalian cells. Therefore, the elucidation of the molecules involved in the parasite–host cell recog- nition process is of extreme importance and remains a focal point of investigation. Attachment is the main key for the parasite to enter the host cell. Evidences have been demonstrated that carbohydrate residues on the surface of both parasite and the host cell participate in the recognition process (Barbosa and Meirelles, 1992; Bonay et al., 2001; Soeiro et al., 1999). Sialic acid resi- dues have also been demonstrated to play an important role in the parasite-cell recognition (Schenkman et al., 1993; Soeiro et al., 1995), which is mediated by the parasite trans-sialidase (TS) activity that remove the sialic acid from donor molecules and transfers it to its b-galactopyranosyl acceptor (Pereira et al., 1996; Schenkman et al., 1994). Furthermore, it has been re- ported that inactive TS, members of TS family with a lack of the enzymatic activity, promote the parasite–host interface. Recently, it has been demonstrated that both * Corresponding author. Fax: +55-21-2260-4434. E-mail address: mirian@ioc.fiocruz.br (M.C.S. Pereira). 0014-4894/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.exppara.2004.04.003 Experimental Parasitology 107 (2004) 20–30 www.elsevier.com/locate/yexpr