Brucella abortus infection elicits hepatic stellate cells (HSC) fibrosis through inflammasome dependent IL-1β production.

AYELÉN IVANA PESCE VIGLIETTI; MARIA VICTORIA DELPINO; PAULA CONSTANZA ARRIOLA BENITEZ; GUILLERMO H GIAMBARTOLOMEI; DIEGO COMERCI

Congreso; 62. LXIV Reunión Anual de la Sociedad Argentina de Inmunología (SAI). 15-19 Noviembre 2016.; 2016

ggers on HSC a profibrotic response characterized by inhibitionof MMP-9 with concomitant collagen deposition and TGF-b1secretion in a way that involved a functional T4SS. Taking intoaccount that it has been reported that inflammasome is necessaryto induce a fibrotic phenotype in HSC, we hypothesized thatBrucella infection might create a microenvironment that wouldpromote inflammasome activation and a concomitant profibrogenicphenotype in HSC. Our results indicate that Ba infection inducesIL-1b secretion (ELISA) by LX-2 cells by a mechanism dependenton a functional T4SS (p<0.001). When infection experiments wereperformed in the presence of glyburide, a compound that inhibitsNLRP3 inflammasome, the secretion of IL-1b was significantlyinhibited respect to uninfected controls (p<0.001). The same effectwas observed when infection was performed in the presence ofspecific caspase-1 inhibitor Ac-YVAD-cmk (p<0.001). These resultsindicate that caspase-1 and NLRP3 are involved in IL-1â secretionby Ba-infected LX-2 cells. Then experiments were conducted todetermine whether expression of inflammasome components couldbe upregulated during Ba infection. We determine the expressionof caspase-1, NLRP3 and ASC by qRT-PCR. Our results indicatedthat Ba infection induces an increase in caspase-1 and NLRP3mRNA expression (p<0.01) but was unable to modified ASCexpression. We proposed to determine the role of inflammasomein the induction of a fibrogenic phenotype in LX-2 cells during Bainfection. To this end the levels of MMP-9 (zymography), TGF-b(ELISA) and collagen (Sirius red staining) were determined inLX-2 cells that were infected with Ba in presence of Ac-YVADcmkand glyburide. Both inhibitors were able to reverse the effectof Ba infection on LX-2 cells. Taken together this results indicatethat Ba induce inflammasome activation in HSC with concomitantinduction of a fibrotic phenotype.