|Bone homeostasis is regulated through osteoclasts, osteoblasts and osteocyte. Osteoblasts are differentiated from bone marrow mesenchymal stem cells and stimulate bone formation and calcification. Osteoclasts are developed from hematopoietic progenitors and promote bone resorption. Physiologic process of bone turnover through these bone cells underpins development and maintenance of the skeletal system. This process is dexterously regulated through various physiological systems including hormones, cytokines and bone marrow environments.
Bone marrow mesenchymal stem cells are multipotent stromal cells, which among other cell lineages, that can differentiate into a variety of cell types including osteoblasts (bone cells), chondrocytes (cartilage cells), myoblasts (heart cells) and adipocytes (fat cells). This occurs through cross talk between complex signaling pathways including those derived from bone morphogenic proteins (BMPs), winglesstype MMTV integration site (Wnt) proteins, hedgehogs, delta/ jagged proteins, fibroblastic growth factors, insulin, insulin-like growth factors, and transcriptional regulators of adipocyte and osteoblast differentiation including peroxisome proliferators-activated receptorgamma (PPARÎ³) and runt-related transcription factor 2 (Runx2). Differentiation of bone marrow mesenchymal stem cells may be involved in the development of osteoporosis.
Masayoshi Yamaguchi, Bone Marrow Mesenchymal Stem Cell Differentiation: Involvement in Osteoporosis with Obesity and Diabetes