Transcriptional Regulation of NAMPT Gene by Glycogen Synthase Kinase 3β in Goat Adipocytes.

Nicotinamide phosphoribosyl transferase (NAMPT) is a cytokine which is secreted by adipose tissue and involved in the process of immunoreactions, inflammation, and lipid metabolism through the endocrine or paracrine. However, the information regarding NAMPT and its transcriptional regulation in goats remains unknown. In this study, the inactivation of glycogen synthase kinase 3β (GSK3β) decreased the supernatant NAMPT productions in goat adipocytes. The luciferase activities were kept in high levels in pGL3 (-735/+34) and the deletion from -735 bp to -486 bp significantly decreased the luciferase activity (p < 0.01). In addition, a peroxisome proliferator-activated receptor gamma (PPARγ) element in this region was responsible for NAMPT promoter activity. The transcription activity of PPARγ was activated by SB216763 stimulation and failed to induce luciferase activity of the pGL3 (Mut-PPARγ-735/+34). In contrast, the GSK3β overexpression repressed luciferase activity of the NAMPT promoter. Besides, chromatin immunoprecipitation assay indicated that PPARγ was capable of binding to the NAMPT promoter, and inhibition of GSK3β increased the binding capacity of PPARγ to the NAMPT promoter. These results confirm the role of GSK3β as a negative regulator of NAMPT transcription in goat adipocytes, and GSK3β-regulated expression of NAMPT is mediated by PPARγ.