Osteoclastogenesis Functional Study of Osteoclasts Precursors from Gaucher Disease Patients

MUCCI J M; DELPINO M.; ROZENFELD P.

Simposio; Lisosomal Disease Network World Symposium; 2014

Pathological mechanisms of skeletal manifestations of Type I Gaucher disease (GD), including osteopenia and osteonecrosis, are still poorly understood. Inflammation is a key factor in the pathogenesis of GD and increased bone resorption markers have been described in patients. RANKL \ OPG \ RANK axis has been described as the central regulator of osteoclast differentiation. Previous results from our group showed an increase in circulating osteoclast precursors in blood from GD patients and higher differentiation towards TRAP+ cells. In addition we have revealed that the addition of conditioned media (CM) from GD patients´PBMC induced higher osteoclastogenesis levels, and this process was partially mediated by TNF-α and RANKL. The aim of this study is to characterize osteoclast resorption activity from GD patients´cells and assess the effect of velaglucerase (VPRIV, SHire HGT, USA) on osteoclast differentiation. PBMC were cultured in the presence of M-CSF on dentine covered wells and osteoclast activity was determined by counting pit formation. The same experiment was carried out but in the presence of velaglucerase and osteoclast differentiation was assessed by counting TRAP positive multinucleated cells. Osteoclast precursors obtained from THP-1 cells were stimulated with CM in the presence of a TNF-α neutralizing antibody or osteoprotegerin (OPG) and resorption activity was studied. Number of resorption pits obtained from GD PBMC was increased 4 times as compared to normal controls PBMC (p <0.05). The addition of velaglucerase resulted in a decrease in osteoclast differentiation from GD patients PBMCs. The activity of osteoclasts differentiated from GD conditioned media was higher as compared to controls (p<0.05), and the neutralization of TNF-α or RANKL diminished osteoclast activity to control levels. Our findings show that the greater numbers of OP in circulation of patients with GD and the increased osteoclast differentiation capacity are correlated to a higher resorptive activity and that soluble mediators produced by PBMCs from GD patients have the ability to induce osteoclastogenesis and this could contribute to bone involvement in GD. As preliminary results velaglucerase treatment would diminish the osteoclastogenesis potential of osteoclast precursors in circulation from Gaucher disease patients.This work was supported by a grant from Shire HGT (USA) [IIR-ARG-000120 to PR]. References: Mucci, J. M., et al. (2012) Gene, 509 (1), 51?9. Lecourt, S., et al. (2011) Stem cells and development, 1?33.