Down Regulation of NO Signaling in Trypanosoma cruzi upon Parasite-Extracellular Matrix Interaction: Changes in Protein Modification by Nitrosylation and Nitration

Author(s)

Pereira, Milton ^[1] ; Soares, Chrislaine ^[1] ; Baptista Canuto, Gisele Andre ^[2] ; Maggi Tavares, Marina Franco ^[2] ; Colli, Walter ^[1] ; Alves, Maria Julia M. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-01498 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, Sao Paulo - Brazil

• Document type: Journal article
• Source: PLoS Neglected Tropical Diseases; v. 9, n. 4 APR 2015.
• Web of Science Citations: 5

Abstract

Background Adhesion of the Trypanosoma cruzi trypomastigotes, the causative agent of Chagas' disease in humans, to components of the extracellular matrix (ECM) is an important step in host cell invasion. The signaling events triggered in the parasite upon binding to ECM are less explored and, to our knowledge, there is no data available regarding center dot NO signaling. Methodology/Principal Findings Trypomastigotes were incubated with ECM for different periods of time. Nitrated and S-nitrosylated proteins were analyzed by Western blotting using anti-nitrotyrosine and S-nitrosyl cysteine antibodies. At 2 h incubation time, a decrease in NO synthase activity, center dot NO, citrulline, arginine and cGMP concentrations, as well as the protein modifications levels have been observed in the parasite. The modified proteins were enriched by immunoprecipitation with anti-nitrotyrosine antibodies (nitrated proteins) or by the biotin switch method (S-nitrosylated proteins) and identified by MS/MS. The presence of both modifications was confirmed in proteins of interest by immunoblotting or immunoprecipitation. Conclusions/Significance For the first time it was shown that T. cruzi proteins are amenable to modifications by S-nitrosylation and nitration. When T. cruzi trypomastigotes are incubated with the extracellular matrix there is a general down regulation of these reactions, including a decrease in both NOS activity and cGMP concentration. Notwithstanding, some specific proteins, such as enolase or histones had, at least, their nitration levels increased. This suggests that post-translational modifications of T. cruzi proteins are not only a reflex of NOS activity, implying other mechanisms that circumvent a relatively low synthesis of center dot NO. In conclusion, the extracellular matrix, a cell surrounding layer of macromolecules that have to be trespassed by the parasite in order to be internalized into host cells, contributes to the modification of center dot NO signaling in the parasite, probably an essential move for the ensuing invasion step. (AU)

• FAPESP's process: 12/03887-3 - Identification of Trypanosoma cruzi proteins modified by S-nitrosylation and nitration after adhesion to extracellular matrix.
• Grantee: Milton César de Almeida Pereira
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 12/05621-0 - Nitric oxide cell signaling during Trypanosoma cruzi differentiation and adhesion to extracellular matrix
• Grantee: Chrislaine Oliveira Soares
• Support Opportunities: Scholarships in Brazil - Post-Doctoral