Papel imunorregulador da Hsp70 de Mycobacterium tuberculosis, murina e humana

Abstract

Hsp70 (Heat shock protein 70 kDa) is a chaperone protein which has intra- and extracellular functions. In the early studies, only intracellular functions were operated, as to aid in folding, prevent aggregation and protein refolding. In 80’s a study has shown that this protein can be exported into the extracellular environment exerting effects on other cells, such as the immune system. Our group are exploring the role of this protein in key immune response cells such as macrophages and dendritic cells. Present study noted that the Hsp70 of Mycobacterium tuberculosis can polarize macrophages to a M2 phenotype and this response is dependent on IL-10. Peritoneal and bone marrow derived macrophages were treated with DnaK (Hsp70 prokaryotic homolog) from M. tuberculosis for 24 hours. After this period there was an increase of M2 classic phenotype markers, such as FIZZ1, YM1, CD206, IL-10 and Arg1. On the other hand, there was a decrease in expression of IL-6, MCP-1, TNF-α, NO, MHC class II and CD86 (M1 markers), and these cells are able to promote tumor growth in allogeneic model. It was also observed with KO cells or blocking IL-10R that this modulation is dependent on IL-10. In addition, this cellular modulation is not restricted to macrophages; such protein acting on dendritic cells by modulating them with an immature phenotype, as has been shown in prior works of our group (Borges et al, 2010;. Motta et al., 2007 ). However, it is not yet known what specific region of the protein is essential for that purpose and whether it is restricted to that homologues, DnaK from M. tuberculosis. Therefore, another objective was to express and purify in the same system their counterparts Hspa1a (murine Hsp70) and HSPA1A (human Hsp70) and subsequently testing them in parallel in immunological experimental models. Work is currently in progress with regard to purification of Hspa1a and initial dendritic cells activation state tests were conducted. It is believed that whether there is an effect with DnaK homologues, this effect is less obvious, according to previous results.