MYCOBACTERIUM LEPRAE INDUCES MMP9 EXPRESSION AND ACTIVITY IN PBMC FROM LEPROSY PATIENTS

Rosane Teles (FIOCRUZ); Rose Teles (FIOCRUZ); Thaís Amadeu (FIOCRUZ); Danielle Moura (FIOCRUZ); Leila Mendonça-lima (FIOCRUZ); José Nery (FIOCRUZ); Euzenir Sarno (FIOCRUZ); Elizabeth Sampaio (NIAID)

Gelatinases A and B (MMP-2 and MMP-9) can induce basal membrane breakdown and leukocyte migration, but their role in leprosy skin inflammation remains unclear. Considering the participation of MMPs in the disease, the aims of this study were: 1) to determine whether Mycobaterium leprae (ML) is able to induce the production MMP-9; 2) to determine whether both pro- and active MMP-9 proteins can be detected in the M. leprae-stimulated cultures; and 3) to investigate whether M. leprae and TNFa could drive MMP production in vitro. For that, PBMCs from leprosy patients were stimulated in vitro with ML, TNFa or ML + TNFa after different culture periods, and mRNA, protein expression and zymography were performed. By in vitro stimulation of PBMCs, ML induced the expression of MMP-9 (mRNA and protein) from the cultured cells. Data confirm the ability of ML to induce the expression of the active forms of MMP-9. Since TNFa has been shown to promote MMP secretion, we investigated whether M. leprae and TNFa could drive MMP production in vitro. MMP-9 mRNA was increased in the presence of TNFa (p<0.05) or ML (p<0.05), and ML+TNFa (p<0.001) in comparison to control cells. In addition, the increase of MMP-9 mRNA was detected when ML+TNFa stimulated cells were compared with ML- or TNFa-stimulated cultures (p<0.05). MMP-9 levels in culture supernatants induced by ML+TNF (mean = 64.5 ± 7.3ng/ml) were higher than those induced by ML (45 ± 8ng/ml). mRNA expression induced by ML+TNF, although slightly elevated in comparison to ML alone (p>0.05); protein levels were not altered by M. leprae or TNF. Our results demonstrate that ML induces MMP-9 expression and activity in PBMCs from leprosy patients and that TNF synergizes with M. leprae in the induction of MMP-9 in PBMC cultures. These results pave the way to new therapeutic interventions to be applied in leprosy patients. Supported by FIOCRUZ, CNPq.