| First Author | Yoon J | Year | 2017 |
| Journal | Biochem Biophys Res Commun | Volume | 487 |
| Issue | 3 | Pages | 600-606 |
| PubMed ID | 28435063 | Mgi Jnum | J:250797 |
| Mgi Id | MGI:6102490 | Doi | 10.1016/j.bbrc.2017.04.098 |
| Citation | Yoon J, et al. (2017) Regulation of Nampt expression by transcriptional coactivator NCOA6 in pancreatic beta-cells. Biochem Biophys Res Commun 487(3):600-606 |
| abstractText | Nuclear receptor coactivator 6 (NCOA6) is a transcriptional coactivator and crucial for insulin secretion and glucose metabolism in pancreatic beta-cells. However, the regulatory mechanism of beta-cell function by NCOA6 is largely unknown. In this study, we found that the transcript levels of nicotinamide phosphoribosyltransferase (Nampt) were decreased in islets of NCOA6(+/-) mice compared with NCOA6(+/+) mice. Moreover, NCOA6 overexpression increased the levels of Nampt transcripts in the mouse pancreatic beta-cell line NIT-1. Promoter analyses showed that transcriptional activity of the Nampt promoter was stimulated by cooperation of sterol regulatory element binding protein-1c (SREBP-1c) and NCOA6. Additional studies using mutant promoters demonstrated that SREBP-1c activates Nampt promoter through the sterol regulatory element (SRE), but not through the E-box. Using chromatin immunoprecipitation assay, NCOA6 was also shown to be directly recruited to the SRE region of the Nampt promoter. Furthermore, treatment with nicotinamide mononucleotide (NMN), a product of the Nampt reaction and a key NAD(+) intermediate, ameliorates glucose-stimulated insulin secretion from NCOA6(+/-) islets. These results suggest that NCOA6 stimulates insulin secretion, at least partially, by modulating Nampt expression in pancreatic beta-cells. |
