Interdependency of stromal and hematopoietic bone marrow cell differentiation and their effects on bone remodeling. Bone marrow-derived mesenchymal stem cells (BMSC) differentiate mainly into adipocytes or osteoblast cells (OBC) in a reciprocal manner. Hematopoietic stem cells (HSC) differentiate into osteoclasts (OC) besides other blood cells. Osteoblasts and osteoclasts deposit and erode the bone matrix, respectively. Fatty acids (FA) bind to PPARγ. PPARγ regulates the lineage commitment of both BMSC toward adipocytes and away from osteoblasts, and of myeloid progenitors toward OC. In adipocytes, PPARγ stimulation regulates adipokine secretion. Adipokines positively regulate osteoblastogenesis and negatively regulate osteoclastogenesis. Osteoclastogenesis is positively regulated by M-CSF and RANKL, which can be secreted by OBCs. OC secrete IGF-1 and TGFβ, which drive OBC differentiation