Enzymes in the NAD+ Salvage Pathway Regulate SIRT1 Activity at Target Gene Promoters

• Published in: The Journal of biological chemistry Vol. 284; no. 30; pp. 20408 - 20417
• Main Authors: Zhang, Tong, Berrocal, Jhoanna G., Frizzell, Kristine M., Gamble, Matthew J., DuMond, Michelle E., Krishnakumar, Raga, Yang, Tianle, Sauve, Anthony A., Kraus, W. Lee
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 24.07.2009; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; Cell Line, Tumor; Cytokines - genetics; Cytokines - metabolism; Female; Gene Expression Regulation; Humans; Mice; NAD - metabolism; Nicotinamide Phosphoribosyltransferase - genetics; Nicotinamide Phosphoribosyltransferase - metabolism; Nicotinamide-Nucleotide Adenylyltransferase - genetics; Nicotinamide-Nucleotide Adenylyltransferase - metabolism; Promoter Regions, Genetic; Sirtuin 1; Sirtuins - genetics; Sirtuins - metabolism; Transcription, Chromatin, and Epigenetics
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M109.016469

In mammals, nic o tin a mide phosphoribosyltransferase (NAMPT) and nic o tin a mide mononucleotide ad en y lyltransferase 1 (NMNAT-1) constitute a nuclear NAD+ salvage pathway which regulates the functions of NAD+-de pend ent enzymes such as the protein deacetylase SIRT1. One of the major functions of SIRT1 is to regulate target gene transcription through modification of chromatin-associated proteins. However, little is known about the molecular mechanisms by which NAD+ biosynthetic enzymes regulate SIRT1 activity to control gene transcription in the nucleus. In this study we show that stable short hairpin RNA-mediated knockdown of NAMPT or NMNAT-1 in MCF-7 breast cancer cells reduces total cellular NAD+ levels and alters global patterns of gene expression. Furthermore, we show that SIRT1 plays a key role in mediating the gene regulatory effects of NAMPT and NMNAT-1. Specifically, we found that SIRT1 binds to the promoters of genes commonly regulated by NAMPT, NMNAT-1, and SIRT1 and that SIRT1 histone deacetylase activity is regulated by NAMPT and NMNAT-1 at these promoters. Most significantly, NMNAT-1 interacts with, and is recruited to target gene promoters by SIRT1. Collectively, our results reveal a mechanism for the direct control of SIRT1 deacetylase activity at a set of target gene promoters by NMNAT-1. This mechanism, in collaboration with NAMPT-de pend ent regulation of nuclear NAD+ production, establishes an important pathway for transcription regulation by NAD+.