P03-021 - Characterization of BM-MSC from osteopetrotic mice

Introduction Autosomal Recessive Osteopetrosis (ARO) is a severe bone disease characterized by increased bone density due to impairment in osteoclast bone resorptive function (osteoclast-rich forms) or differentiation (osteoclast-poor forms). The latter form carries mutations in Tnfsf11 gene, which codifies for the receptor activator of NFB ligand (RANKL), an essential cytokine expressed in stromal cells. It contributes (with M-CSF) to the differentiation and activation of specialized osteoclasts from monocyte precursors in bone marrow niche. These patients, differently from other forms, do not benefit from HSC transplantation, demonstrating a pathogenetic role of stromal cells in unbalanced bone remodeling.