Abstract

Bone is the only solid organ and serves as a mechanical support and a reservoir of minerals. Bone homeostasis is achieved by the balance between bone-forming osteoblasts and bone-resorbing osteoclasts. Osteoblasts, which are derived from mesenchymal stem cells, secrete bone matrix proteins and promote mineralization. Otherwise, osteoclasts are derived from hematopoietic stem cells (HSC) that are capable of differentiating into all immune cells and resorb bone matrix by acid decalcification and proteolytic degradation. Osteobalsts and osteoclasts are an important role in the regulation of HSC niche and development, showing that bone remodeling was linked to hematopoietic regulation. Long-lived memory T and B cells and bone cells coexist in the bone marrow reservoir as well as activated T cells that mediate adaptive immune system and osteoclasts that regulate bone turnover share a common molecules that are essential for their development and differentiation. In addition, activated T cell-expressed RANKL directly stimulates osteoclastogenesis. Accumulating evidence indicates that there is the interplay between the immune-related cells and bone remodeling-related cells. This review will discuss the osteoimmunology, an interdisciplinary approach to understanding the cross-talk between bone and the immune cells.

• Keywords: Bone, Osteoblast, Osteoclast, Immune cells, Osteoimmunology