Brucella abortus induces neuronal death through activation of microglia

RODRIGUEZ, A. M.; MIRAGLIA, M. C.; COSTA FRANCO, MIRIAM M.; OLIVEIRA, SERGIO C.; BARRIONUEVO P.; JANCIC, CAROLINA; DELPINO, M.V.; GIAMBARTOLOMEI, G.H.

Los cocos, Cordoba

Congreso; LXI Reunion Anual de la Sociedad Argentina de Inmunologia; 2013

SAI

Central nervous system invasion by bacteria of the genus Brucella results in an inflammatory disorder called neurobrucellosis. B. abortus infects astrocytes and microglia, eliciting the production of pro-inflammatory cytokines which in turn induce glial apoptosis. The aim of this study was to determine the mechanisms of neuronal death induced by B. abortus. We evaluated the direct role of the bacterium on neurons and the effect that infected glial cell could have on them. For this, murine neurons were cultured alone or co-cultured with microglial cells (primary culture or the BV-2 cell line) in the presence or not of B. abortus. The viability of neurons was determined by microscopy and the secretion of cytokines by ELISA. Both, confocal microscopy using a GFP-B. abortus (multiplicity of infection (MOI) 100) and determination of bacterial load (MOI 1000, 500 and 50) demonstrated that B. abortus was unable to infect neurons or induce their death. Neurons were unable to secrete IL-6 y TNF-α in response to B. abortus (p>0.05 with respect to untreated cells). Yet, when neurons were co-cultured with microglia the number of viable neurons significantly decreased as a function of the number of microglia present in the culture (ratio neuron: microglia 1:20, 1:4, 1:2 and 1:1; p