OSTEOCYTES AND IL-6 CONTRIBUTE TO BONE PATHOLOGY IN GAUCHER DISEASE

CRIVARO ANDREA; MUCCI JUAN MARCOS; FERREYRA MALENA; BONDAR CONSTANZA; ORMAZABAL MAXIMILIANO; DELPINO MARIA VICTORIA; ROZENFELD PAULA

Congreso; LXIV REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA; 2016

Gaucher disease is caused by deficiency of the lysosomal enzyme glucocerebrosidase leading to the accumulation of glucosylceramide. In spite of treatment, bone alterations in Gaucher patients persist. This could rely on the increment of the number of osteoclasts induced by RANK-L and/or citoquines) or the augmented apoptosis of osteocytes. Connexin43 ( Cx43) is expressed in bone cells and its function seems to be essential for survival. The aim of our work was to study the involvement of osteocytes in bone pathology of GD. The study was performed using the MLO-Y4 osteocyte cell line treated with CBE an inhibitor of glyucocerebrosidase at different time points. The osteoclastogenic potential of conditioned media (CM) from CBE treated osteocytes was evaluated by osteoclast differentiation assays; and RANK-L levels in osteocytes were evaluated by immunofluorescence. Cx43 expression was measured by qPCR and apoptosis was studied by Annexin-V and TUNEL staining. On the other hand, osteoclastogenesis assays were performed with the apoptotic body fraction of CM and the supernatant fraction of the CM both in the presence or absence of OPG. The CM from CBE treated osteocytes induced higher levels of osteoclast differentiation compared to control CM and higher surfaceRANK-L levels were observed in treated cells. Cx43 expression diminished with CBE treatment and osteocyte apoptosis was increased. The induction of osteoclast differentiation by apoptotic bodies and supernatant Yas higher in C$E treated CM by both fractions and OPG treatment reduced osteoclast levels in both cases. Levels of IL-6, TNFá and IL-1ª, were evaluated by ELISA in supernatant. Only IL-6 levels presented an increment in CBE supernatant. In conclusion, we have shown the possible involvement of osteocytes in bone pathology of GD through an induction of osteoclast differentiation. This induction would be related to a higher apoptotic state of osteocytes that could involve Cx43 as well as RANK-L and IL-6.