Vitamin B6 regulates mRNA expression of peroxisome proliferator-activated receptor-γ target genes

We previously demonstrated that vitamin B6 suppresses tumorigenesis in the colon of mice and exerts an anti-inflammatory effect through the inhibition of NF-kappa B activation. As these effects resemble the pharmacological properties of thiazolidinedione (TZD), a synthetic peroxisome proliferator activated receptor-gamma (PPAR gamma) ligand, this study was designed to examine the effect of vitamin B6 on the activation of PPAR gamma and adipogenesis in 3T3-L1 adipocyte cells. Pyridoxal 5'-phosphate (PLP), one of the vitamin B6 derivatives, was shown to promote adipogenesis in the 3T3-L1 adipocytes. In addition, PLP specifically induced mRNA expression of PPAR gamma target genes in the 3T3-L1 adipocytes and enhanced the lipid accumulation and adipocyte fatty acid-binding protein (aP2) mRNA expression in NIH3T3 cells stably expressing PPAR gamma. Furthermore, the administration of vitamin B6 increased the expression of aP2 mRNA in mouse adipose tissues. Collectively, these observations suggest a novel function of vitamin B6 as an activator for PPAR gamma, which may contribute to the anti-tumor and anti-inflammatory effects of vitamin B6.