Commitment to the Osteoblast Lineage Is Not Required for RANKL Gene Expression

摘要: Differentiation of bone-resorbing osteoclasts from hematopoietic precursors depends upon expression the cytokine receptor activator NFκB ligand (RANKL) by fibroblastic stromal cells, which some evidence suggests are osteoblast lineage. We have shown previously that hormonal-responsiveness murine RANKL gene is mediated in part a distal enhancer binds Runx2, transcription factor required for commitment to lineage, supporting idea osteoclast-supporting cells may be osteoblasts or their progenitors. However, this study we demonstrate parathyroid hormone (PTH) stimulation mice not affected significant reduction number osteoblasts. Consistent with this, neither nor Cbfb, binding partner essential Runx activity, basal PTH-stimulated cell models. Nonetheless, responsiveness PTH was elevated cultured calvaria expressing high levels osterix, another differentiation, and associated expression. The 1,25-dihydroxyvitamin D3 osterix-expressing cells. Together, these results suggest lineage requirement but enhance specific hormones via control receptors.