Purine nucleoside phosphorylase controls nicotinamide riboside metabolism in mammalian cells.

Content Provider	Europe PMC
Author	Kropotov, Andrey Kulikova, Veronika Solovjeva, Ljudmila Yakimov, Alexander Nerinovski, Kirill Svetlova, Maria Sudnitsyna, Julia Plusnina, Alena Antipova, Maria Khodorkovskiy, Mikhail Migaud, Marie E. Gambaryan, Stepan Ziegler, Mathias Nikiforov, Andrey
Copyright Year	2022
Abstract	Nicotinamide riboside (NR) is an effective precursor of nicotinamide adenine dinucleotide (NAD) in human and animal cells. NR supplementation can increase the level of NAD in various tissues and thereby improve physiological functions that are weakened or lost in experimental models of aging or various human pathologies. However, there are also reports questioning the efficacy of NR supplementation. Indeed, the mechanisms of its utilization by cells are not fully understood. Herein, we investigated the role of purine nucleoside phosphorylase (PNP) in NR metabolism in mammalian cells. Using both PNP overexpression and genetic knockout, we show that after being imported into cells by members of the equilibrative nucleoside transporter family, NR is predominantly metabolized by PNP, resulting in nicotinamide (Nam) accumulation. Intracellular cleavage of NR to Nam is prevented by the potent PNP inhibitor Immucillin H in various types of mammalian cells. In turn, suppression of PNP activity potentiates NAD synthesis from NR. Combining pharmacological inhibition of PNP with NR supplementation in mice, we demonstrate that the cleavage of the riboside to Nam is strongly diminished, maintaining high levels of NR in blood, kidney, and liver. Moreover, we show that PNP inhibition stimulates Nam mononucleotide and NAD+ synthesis from NR in vivo, in particular, in the kidney. Thus, we establish PNP as a major regulator of NR metabolism in mammals and provide evidence that the health benefits of NR supplementation could be greatly enhanced by concomitant downregulation of PNP activity.
ISSN	00219258
Volume Number	298
PubMed Central reference number	PMC9667316
Issue Number	12
PubMed reference number	36265580
Journal	The Journal of Biological Chemistry [J. Biol. Chem]
e-ISSN	1083351X
DOI	10.1016/j.jbc.2022.102615
Language	English
Publisher	American Society for Biochemistry and Molecular Biology
Publisher Date	2022-10-18
Access Restriction	Open
Rights License	This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). © 2022 The Authors
Subject Keyword	nicotinamide adenine dinucleotide (NAD) NAD biosynthesis nicotinamide riboside metabolism purine nucleoside phosphorylase human mouse ENTs, equilibrative nucleoside transporters FBS, fetal bovine serum NA, nicotinic acid mESC, mouse embryonic stem cells NAD, nicotinamide adenine dinucleotide Nam, nicotinamide NAMN, NA mononucleotide NAMPT, Nam phosphoribosyltransferase NAPRT, NA phosphoribosyltransferase NBTI, S-(4-nitrobenzyl)-6-thioinosine NMN, Nam mononucleotide NMNAT, NMN adenylyltransferase NR, nicotinamide riboside NRH, reduced form of nicotinamide riboside NRK, NR kinase PNP, purine nucleoside phosphorylase RBCs, red blood cells
Content Type	Text
Resource Type	Article
Subject	Cell Biology Molecular Biology Biochemistry