,%20a%20form%20of%20vitamin%20B3,%20is%20known%20to%20boost%20levels%20of%20NAD+,%20a%20vital%20molecule%20for%20energy%20production%20and%20cellular%20repair.%20However,%20how%20NR%20gets%20into%20cells%20has%20remaine...){kind=link}
Equilibrative Nucleoside Transporters Transport Nicotinamide Riboside and Nicotinic Acid Riboside into Human Cells: Preclinical Findings
Synopsis
Nicotinamide riboside (NR), a form of vitamin B3, is known to boost levels of NAD+, a vital molecule for energy production and cellular repair. However, how NR gets into cells has remained unclear. In this study, researchers found that NR enters mammalian cells through specific equilibrative nucleoside transporters (ENT1, ENT2, and ENT4)—proteins that allow small molecules to move across cell membranes. Once inside, NR is quickly converted into nicotinamide (Nam), which supports NAD+ synthesis. The study also showed that a related compound, nicotinic acid riboside (NAR), uses the same transporters but requires activation by another enzyme called NR kinase to be effectively utilized. In contrast, concentrative nucleoside transporters (CNT1–3) did not play a major role in NR uptake. These findings clarify how NR functions at the cellular level and could help optimize its use in metabolism, aging, and disease research.
Journal
International Journal of Molecular Sciences