Phosphate restriction impairs mTORC1 signaling leading to increased bone marrow adipose tissue and decreased bone in growing mice.

Bone marrow stromal cells (BMSCs) are multipotent cells that differentiate into cells of the osteogenic and adipogenic lineage. A striking inverse relationship between bone marrow adipose tissue (BMAT) and bone volume is seen in several conditions, suggesting that differentiation of BMSCs into bone marrow adipocytes diverts cells from the osteogenic lineage, thereby compromising the structural and mechanical properties of bone. Phosphate restriction of growing mice acutely decreases bone formation, blocks osteoblast differentiation and increases BMAT.