Common and distinct roles of AMPKγ isoforms in small-molecule activator-stimulated glucose uptake in mouse skeletal muscle

TY - JOUR

T1 - Common and distinct roles of AMPKγ isoforms in small-molecule activator-stimulated glucose uptake in mouse skeletal muscle

AU - Biswas, Dipsikha

AU - Espino-Gonzalez, Ever

AU - Ahwazi, Danial

AU - Freemantle, Jordana B

AU - Ehrlich, Amy M

AU - Jomard, Charline

AU - Brorson, Jonas

AU - Schou, Agnete N

AU - Farup, Jean

AU - Gondin, Julien

AU - Just, Jesper

AU - Foretz, Marc

AU - Treebak, Jonas T

AU - Agerholm, Marianne

AU - Sakamoto, Kei

N1 - Copyright © 2025 The Author(s). Published by Elsevier GmbH.. All rights reserved.

PY - 2026/1

Y1 - 2026/1

N2 - Objectives: Small-molecule activators targeting the allosteric drug and metabolite (ADaM) site of AMPK enhance insulin-independent glucose uptake in skeletal muscle and lower glucose in preclinical models of hyperglycemia. The regulatory AMPKγ subunit plays a central role in energy sensing. While the skeletal muscle-selective γ3 isoform is essential for AMP/ZMP-induced glucose uptake, it is dispensable for ADaM site-binding activators. We hypothesized that the predominant γ1 isoform is required for ADaM site activator-stimulated glucose uptake in skeletal muscle. Methods: Single-nucleus RNA sequencing (snRNA-seq) was performed on mouse and human skeletal muscle mapping AMPK subunit isoform distribution across resident cell types. To determine γ isoform-specific requirements for activator-stimulated glucose uptake, skeletal muscle-specific inducible AMPKγ1/γ3 double knockout (imγ1−/−/γ3−/−) and single knockout (imγ1−/− and imγ3−/−) mice were generated. Ex vivo glucose uptake was measured following treatment with AICAR (AMP-mimetic) or MK-8722 (ADaM site activator), and in vivo MK-8722-induced blood glucose lowering was assessed. Results: snRNA-seq revealed distinct AMPK isoform distribution: γ1 was ubiquitously expressed, whereas γ3 was enriched in glycolytic myofibers in both mouse and human skeletal muscle. Ex vivo, glucose uptake stimulated by either AICAR or MK-8722 was severely blunted in imγ1−/−/γ3−/− muscle, and MK-8722-induced blood glucose lowering was significantly blunted in vivo. AICAR but not MK-8722-stimulated muscle glucose uptake was abolished in imγ3−/−, whereas both activators fully retained effects on glucose uptake and glucose lowering in imγ1−/− mice. Conclusions: While γ1 predominates in stabilizing the AMPKα2β2γ1 complex, it is dispensable for AMPK activator-stimulated glucose uptake in skeletal muscle, whether mediated via the nucleotide-binding or ADaM site.

AB - Objectives: Small-molecule activators targeting the allosteric drug and metabolite (ADaM) site of AMPK enhance insulin-independent glucose uptake in skeletal muscle and lower glucose in preclinical models of hyperglycemia. The regulatory AMPKγ subunit plays a central role in energy sensing. While the skeletal muscle-selective γ3 isoform is essential for AMP/ZMP-induced glucose uptake, it is dispensable for ADaM site-binding activators. We hypothesized that the predominant γ1 isoform is required for ADaM site activator-stimulated glucose uptake in skeletal muscle. Methods: Single-nucleus RNA sequencing (snRNA-seq) was performed on mouse and human skeletal muscle mapping AMPK subunit isoform distribution across resident cell types. To determine γ isoform-specific requirements for activator-stimulated glucose uptake, skeletal muscle-specific inducible AMPKγ1/γ3 double knockout (imγ1−/−/γ3−/−) and single knockout (imγ1−/− and imγ3−/−) mice were generated. Ex vivo glucose uptake was measured following treatment with AICAR (AMP-mimetic) or MK-8722 (ADaM site activator), and in vivo MK-8722-induced blood glucose lowering was assessed. Results: snRNA-seq revealed distinct AMPK isoform distribution: γ1 was ubiquitously expressed, whereas γ3 was enriched in glycolytic myofibers in both mouse and human skeletal muscle. Ex vivo, glucose uptake stimulated by either AICAR or MK-8722 was severely blunted in imγ1−/−/γ3−/− muscle, and MK-8722-induced blood glucose lowering was significantly blunted in vivo. AICAR but not MK-8722-stimulated muscle glucose uptake was abolished in imγ3−/−, whereas both activators fully retained effects on glucose uptake and glucose lowering in imγ1−/− mice. Conclusions: While γ1 predominates in stabilizing the AMPKα2β2γ1 complex, it is dispensable for AMPK activator-stimulated glucose uptake in skeletal muscle, whether mediated via the nucleotide-binding or ADaM site.

KW - AICAR

KW - AMP-activated protein kinase

KW - Glucose uptake

KW - MK-8722

KW - Single nucleus RNA sequencing

UR - https://www.scopus.com/pages/publications/105024318645

U2 - 10.1016/j.molmet.2025.102294

DO - 10.1016/j.molmet.2025.102294

M3 - Journal article

C2 - 41325841

SN - 2212-8778

VL - 103

JO - Molecular Metabolism

JF - Molecular Metabolism

M1 - 102294

ER -