Osteoblasts: Function, development, and regulation

Osteoblasts are derived from a variety of progenitor populations, including bone marrow, neural crest, and periosteal cells. Osteoblasts produce extracellular matrix proteins and paracrine factors that together support formation of bone tissue. The major function of osteoblasts is to produce the organic constituents of the bone extracellular matrix that facilitate its mineralization by inorganic compounds. Mesenchymal stromal/stem cells (MSCs) are considered the developmental precursors of osteoblasts. Transcriptional regulation of gene expression in osteoblasts is controlled by epigenetic events that are important for normal osteoblast differentiation and function. The commitment of MSCs into the osteoblast lineage is controlled by molecular mechanisms including signaling pathways, transcription factors, and epigenetic mechanisms. Epigenetic events coordinated by histone or DNA-modifying proteins and noncoding RNAs amplify and promote retention of tissue specific functions. Understanding these events is essential for understanding bone degeneration and regeneration, and permits design of strategies that may prevent or mitigate bone-related disorders.