Osteoblast-adipocyte lineage plasticity in tissue development, maintenance and pathology

Osteoblasts and adipocytes share a common precursor in adult bone marrow and there is a degree of plasticity between the two cell lineages. This has important implications for the etiology of not only osteoporosis but also several other diseases involving an imbalance between osteoblasts and adipocytes. Understanding the process of differentiation of osteoblasts and adipocytes and their trans-differentiation is crucial in order to identify genes and other factors that may contribute to the pathophysiology of such diseases. Several transcriptional regulators have been shown to control osteoblast and adipocyte differentiation and function. Regulation of cell commitment occurs at the level of the progenitor cell through cross talk between complex signaling pathways and epigenetic mechanisms such as DNA methylation, chromatin remodeling, and microRNAs. Here we review the complex precursor cell microenvironment controlling osteoblastogenesis and adipogenesis during tissue development, maintenance, and pathology.