Vitamin D treatment of senescence accelerated mice (SAM-P/6) induces several regulators of stromal cell plasticity.

In an attempt to understand the regulation of bone marrow multipotential cells plasticity in vivo, we treated 4-month-old SAM-P/6 mice with a constant infusion of either 18 pmol/24 h of 1,25(OH)2D3 or vehicle alone for 6 weeks. In vehicle treated animals 78% +/- 4 adipose volume vs. total volume was stained positive with oil red O as compared to only 32 +/- 3% in 1,25(OH)2D3 treated animals (P < 0.001). Furthermore, we aimed to identify the changes in gene expression induced by 1,25(OH)2D3 in bone marrow cells by analyzing a set of 5440 genes in the NIA 15K Mouse cDNA microarray. Overall, a coordinated regulation of genes which both stimulate osteoblastogenesis and inhibit adipogenesis was observed in 1,25(OH)2D3-treated mice when compared to vehicle treated mice. In summary, this study illustrates the anti-adipogenic effect of 1,25(OH)2D3 in bone cells and identifies some of the possible key signals involved in bone cell plasticity.