INVESTIGADORES
GIAMBARTOLOMEI Guillermo Hernan
congresos y reuniones científicas
Título:
B. abortus infection modulates osteocyte function
Autor/es:
PESCE VIGLIETTI A. I., GENTILINI M. V., ARRIOLA BENÍTEZ P. C., VELÁSQUEZ L. N., GIAMBARTOLOMEI G. H., DELPINO M. V
Reunión:
Congreso; LXII Reunión Científica de la Sociedad Argentina de Inmunología; 2014
Resumen:
Osteoarticular brucellosis is the most common
localization of human active disease. Osteocytes, are the most abundant cells
of bone. They secrete factors that regulate osteoclast differentiation (cells
involved in bone resorption). The aim is to determine if Brucella abortus
(Ba) infection modifies osteocyte (MLO-Y4) function. Cytokine and chemokine
production was determined by ELISA, osteoclast differentiation was determined
by microscopy as the number of multinucleated cells that express
tartrate-resistant acid phosphatase (TRAP). Conexin 43, E11/gp38, integrin-α
and -β, tubulin-α, CD44 expression was determined by qRT-PCR. Apoptosis was
determined by Hoechst dye 33342 (microscopy) and by Annexin V-FITC/Propidium
Iodide (PI) (cytometry). Ba infection induced the secretion of pro-inflammatory
cytokines (IL-6 and TNF-α, but not IL-1β), KC and RANKL (the main regulator of
osteoclastogenesis) by osteocytes. In inflammatory condition TNF-α could be
also involved in osteoclastogenesis. Our results indicated that supernatants
from Ba infected osteocytes could induce osteoclast differentiation of
monocytes in the presence of M-CSF (p<0.001). Using a neutralizing antibody
against TNF-α or osteoprotegerin (OPG), RANKL?s decoy receptor, we determined
that TNF-α and RANKL are involved in osteoclastogenesis induced by supernatants
from Ba- infected osteocytes, since the number of TRAP+
multinucleated cells were significantly reduced (p<0.01). Conexin 43 and
accessory molecules such as E11/gp38, integrin-α and -β, tubulin-α and CD44 are
involved in cell-cell interaction necessary for osteocyte survival. Ba
infection inhibits the expression of all molecules studied (p<0.05). This
indicated that Ba-infection could alter osteocyte survival. We found
that Ba infection induced osteocyte apoptosis, Hoechst dye 33342
(p<0.01) and Annexin V-FITC/ PI (p<0.01). Taking together our results
indicated that Ba-infection could alter osteocyte function contributing
to bone damage.