GIAMBARTOLOMEI Guillermo Hernan
congresos y reuniones científicas
Brucella abortus infected synoviocytes mediate osteoarticular inflammatory damage through induction of apoptosis and MMPs secretion.
SCIAN R. BARRIONUEVO P GIAMBARTOLOMEI G. H. FOSSATI CA BALDI P . C. DELPINO MV
Congreso; 1º Congreso Franco-Argentino de Inmunología; 2010
Osteoarticular complications are common in human brucellosis, but the pathogenic mechanisms involved are largely unknown. Matrix metalloproteinases (MMPs) and apoptosis are involved in joint and bone damage in inflammatory and infectious diseases. First we investigated the production of MMPs by human synoviocytes (line SW982) upon Brucella abortus infection. Since we had found that Brucella-infected human synoviocytes produce IL-8 we also analyzed the role of neutrophils in MMP production and the effects of supernatants from Brucella-infected neutrophils on synoviocytes and viceversa. The production of MMPs was analyzed by zymography and ELISA. Infection with B. abortus induced MMP-2 secretion by synoviocytes (59.63±2.3 ng/ml) and MMP-9 by neutrophils (54.4±2.9 ng/ml). In both cell types MMPs were induced by L-Omp19 lipoprotein from B. abortus (synoviocytes: 92.2±1.4 ; neutrophils 61,2±1 ng/ml), and in synoviocytes this induction was mediated by TLR-2. As mentioned, Brucella-infected synoviocytes may attract neutrophils to the site of infection. Thus, we decided to study the effects of cytokines secreted by neutrophils on the production of MMPs by synoviocytes and viceversa. Supernatants from Brucella-infected neutrophils induced a significant secretion of MMP-2 (70.1±10.6 ng/ml) by uninfected synovial cells as compared with supernatants from uninfected neutrophils. In addition, supernatants from infected synoviocytes induced the production of MMP-9 on neutrophils. Brucella-infection or L-Omp19 stimulation also induced synoviocyte apoptosis as measured by fluorescence microscopy analysis of TUNEL and Hoechst 33342 reactions (Brucella-infected: 40% and 25% apoptotic cells, respectively; L-Omp19 stimulation: 30% and 18%; untreated: 5% and 3%). These results indicate that host-derived MMPs and apoptosis could contribute to the progressive joint destruction observed in Brucella infection.