Suppression of 5'-nucleotidase Enzymes Promotes AMP-activated Protein Kinase (AMPK) Phosphorylation and Metabolism in Human and Mouse Skeletal Muscle
Overview
Authors
Affiliations
The 5'-nucleotidase (NT5) family of enzyme dephosphorylates non-cyclic nucleoside monophosphates to produce nucleosides and inorganic phosphates. We hypothesized that gene silencing of NT5 enzymes to increase the intracellular availability of AMP would increase AMP-activated protein kinase (AMPK) activity and metabolism. We determined the role of cytosolic NT5 in metabolic responses linked to the development of insulin resistance in obesity and type 2 diabetes. Using siRNA to silence NT5C2 expression in cultured human myotubes, we observed a 2-fold increase in the AMP/ATP ratio, a 2.4-fold increase in AMPK phosphorylation (Thr(172)), and a 2.8-fold increase in acetyl-CoA carboxylase phosphorylation (Ser(79)) (p < 0.05). siRNA silencing of NT5C2 expression increased palmitate oxidation by 2-fold in the absence and by 8-fold in the presence of 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside. This was paralleled by an increase in glucose transport and a decrease in glucose oxidation, incorporation into glycogen, and lactate release from NT5C2-depleted myotubes. Gene silencing of NT5C1A by shRNA injection and electroporation in mouse tibialis anterior muscle reduced protein content (60%; p < 0.05) and increased phosphorylation of AMPK (60%; p < 0.05) and acetyl-CoA carboxylase (50%; p < 0.05) and glucose uptake (20%; p < 0.05). Endogenous expression of NT5C enzymes inhibited basal lipid oxidation and glucose transport in skeletal muscle. Reduction of 5'-nucleotidase expression or activity may promote metabolic flexibility in type 2 diabetes.
Uno M, Bono H Animals (Basel). 2024; 14(13).
PMID: 38998110 PMC: 11240496. DOI: 10.3390/ani14131998.
Integrating Genetic and Transcriptomic Data to Identify Genes Underlying Obesity Risk Loci.
Xu H, Gupta S, Dinsmore I, Kollu A, Cawley A, Anwar M medRxiv. 2024; .
PMID: 38903089 PMC: 11188121. DOI: 10.1101/2024.06.11.24308730.
Liu M, Khasiyev F, Sariya S, Spagnolo-Allende A, Sanchez D, Andrews H J Am Heart Assoc. 2023; 12(23):e030935.
PMID: 38038215 PMC: 10727334. DOI: 10.1161/JAHA.123.030935.
The NT5DC family: expression profile and prognostic value in pancreatic adenocarcinoma.
Yu X, Sun R, Yang X, He X, Guo H, Ou C J Cancer. 2023; 14(12):2274-2288.
PMID: 37576396 PMC: 10414034. DOI: 10.7150/jca.85811.
Inborn Errors of Purine Salvage and Catabolism.
Camici M, Garcia-Gil M, Allegrini S, Pesi R, Bernardini G, Micheli V Metabolites. 2023; 13(7).
PMID: 37512494 PMC: 10383617. DOI: 10.3390/metabo13070787.