DECIPHERING THE PUTATIVE ROLE OF HIGH MOBILITY GROUP B PROTEIN FROM Trypanosoma cruzi IN INFLAMMATION

LUIS TAVERNELLI; ROMINA MANARÍN; VIRGINIA PERDOMO; JORGE BARRIOS-PAYÁN; ROGELIO HERNANDEZ PANDO; ESTEBAN SERRA; PAMELA CRIBB

Mar del Plata

Congreso; X Congreso de Protozoología y enfermedades parasitarias.; 2014

High Mobility Group B (HMGB) proteins are evolutionary-conserved ubiquitous proteins described more than 30 years ago and named for their high mobility in SDS-PAGE. As abundant components of chromatin, they act as architectural factors and take part of many nuclear processes like transcriptional regulation, DNA repair and replication. A member of this family of proteins, HMGB1, has gained a lot of interest in the last decade because, besides its nuclear functions, it can be secreted by activated macrophages or passively released by necrotic or injured cells and act as a pro-inflammatory mediator. We previously demonstrated that the HMGB protein from Trypanosoma cruzi (TcHMGB) is a nuclear protein expressed in all life cycle stages with architectural functions. We decided to test if TcHMGB can also act as an immune regulator, as a first approach to study its putative role in Chagas Disease. We first determined the presence of TcHMGB in the supernatants of epimastigote cultures and blood trypomastigotes incubated in PBS by western blot, suggesting the protein can be secreted. Consistent with observations in other organisms, acetylation may be the signal for TcHMGB secretion, since treatment with deacetylase-inhibitors enhance the protein signal in western blots. We then stimulated RAW 264.7 macrophages with the recombinant TcHMGB for different time periods. Culture supernatants were collected and nitric oxide production was analyzed measuring nitrite release by Griess reaction. Also, total RNA was purified from treated macrophages and mRNAs for different cytokines were quantified by qRT-PCR. Recombinant TcHMGB showed to be able of inducing macrophage activation in vitro. Finally, we tested the immune activity in vivo, stimulating male BALBc mice with the recombinant protein for different periods of time. Peritoneal fluid and spleens were collected to test for cytokineproduction. These preliminary results indicate that TcHMGB may have a role in inflammation.