Exp Mol Med.  2008 Apr;40(2):246-253. 10.3858/emm.2008.40.2.246.

Transient downregulation of protein O-N-acetylglucosaminylation by treatment of high-dose nicotinamide in human cells

• Lee HI
• Cho HJ
• Han JA
• Jang SY
• Wang KM
• Kang HT
• Hwang ES

• KMID: 1052947
• DOI: http://doi.org/10.3858/emm.2008.40.2.246

Abstract

Nicotinamide at millimolar concentrations affects cell survival in various conditions, and is being utilized therapeutically in many human diseases. However, the effect of an acute treatment of nicotinamide at such high dose on gene expression and cellular metabolism has rarely been determined previously. In this study, we found that levels of O-N-acetylglucosamin(O- GlcNAc)ylated proteins including Sp1 acutely decreased upon treatment of 10 mM nicotinamide. Concomitantly, Sp1 protein level decreased rapidly through accelerated proteasome-mediated proteolysis. Cotreatment of glucosamine or 2-deoxyglucose, which inhibits protein deGlcNAcylation, effectively blocked the decrease induced by nicotinamide. Interestingly, the decline in the levels of Sp1 and protein O- GlcNAcylation was only transient lasting for two days post treatment, and this pattern matched closely the rapid fluctuation of the cellular [NAD(+)]. Our results suggest a possible link between cellular nicotinamide metabolism and protein O-GlcNAcylation, and an existence of cellular [NAD(+)] homeostasis.

Keyword

acetylglucosamine; cyclin-dependent kinase inhibitor p21; glycosylation; NAD; nicotinamide; SIR1 protein, human; Sp1 transcription factor

MeSH Terms

Acetylglucosamine/*metabolism
Blotting, Western
Dose-Response Relationship, Drug
Down-Regulation/*drug effects
Humans
Hydrolysis
Niacinamide/*pharmacology
Reverse Transcriptase Polymerase Chain Reaction
Sp1 Transcription Factor/metabolism