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Nicotinamide riboside kinases display redundancy in mediating nicotinamide mononucleotide and nicotinamide riboside metabolism in skeletal muscle cells

OBJECTIVE: Augmenting nicotinamide adenine dinucleotide (NAD(+)) availability may protect skeletal muscle from age-related metabolic decline. Dietary supplementation of NAD(+) precursors nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) appear efficacious in elevating muscle NAD(+). H...

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Detalles Bibliográficos
Autores principales: Fletcher, Rachel S., Ratajczak, Joanna, Doig, Craig L., Oakey, Lucy A., Callingham, Rebecca, Da Silva Xavier, Gabriella, Garten, Antje, Elhassan, Yasir S., Redpath, Philip, Migaud, Marie E., Philp, Andrew, Brenner, Charles, Canto, Carles, Lavery, Gareth G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5518663/
https://www.ncbi.nlm.nih.gov/pubmed/28752046
http://dx.doi.org/10.1016/j.molmet.2017.05.011
Descripción
Sumario:OBJECTIVE: Augmenting nicotinamide adenine dinucleotide (NAD(+)) availability may protect skeletal muscle from age-related metabolic decline. Dietary supplementation of NAD(+) precursors nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) appear efficacious in elevating muscle NAD(+). Here we sought to identify the pathways skeletal muscle cells utilize to synthesize NAD(+) from NMN and NR and provide insight into mechanisms of muscle metabolic homeostasis. METHODS: We exploited expression profiling of muscle NAD(+) biosynthetic pathways, single and double nicotinamide riboside kinase 1/2 (NRK1/2) loss-of-function mice, and pharmacological inhibition of muscle NAD(+) recycling to evaluate NMN and NR utilization. RESULTS: Skeletal muscle cells primarily rely on nicotinamide phosphoribosyltransferase (NAMPT), NRK1, and NRK2 for salvage biosynthesis of NAD(+). NAMPT inhibition depletes muscle NAD(+) availability and can be rescued by NR and NMN as the preferred precursors for elevating muscle cell NAD(+) in a pathway that depends on NRK1 and NRK2. Nrk2 knockout mice develop normally and show subtle alterations to their NAD+ metabolome and expression of related genes. NRK1, NRK2, and double KO myotubes revealed redundancy in the NRK dependent metabolism of NR to NAD(+). Significantly, these models revealed that NMN supplementation is also dependent upon NRK activity to enhance NAD(+) availability. CONCLUSIONS: These results identify skeletal muscle cells as requiring NAMPT to maintain NAD(+) availability and reveal that NRK1 and 2 display overlapping function in salvage of exogenous NR and NMN to augment intracellular NAD(+) availability.