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

  • Mol Metab. 2026 Jan:103:102294. doi: 10.1016/j.molmet.2025.102294.
Dipsikha Biswas  1 ,  Ever Espino-Gonzalez  1 ,  Danial Ahwazi  1 ,  Jordana B Freemantle  1 ,  Amy M Ehrlich  1 ,  Charline Jomard  2 ,  Jonas Brorson  3 ,  Agnete N Schou  4 ,  Jean Farup  3 ,  Julien Gondin  2 ,  Jesper Just  4 ,  Marc Foretz  5 ,  Jonas T Treebak  1 ,  Marianne Agerholm  1 ,  Kei Sakamoto  6
Affiliations
  • 1. Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, 2200, Denmark.
  • 2. Institut NeuroMyoGène, Unité Physiopathologie et Génétique du Neurone et du Muscle, Université Claude Bernard Lyon 1, CNRS UMR 5261, Inserm U1315, Univ Lyon, Lyon, France.
  • 3. Department of Biomedicine, Aarhus University, Aarhus, 8000, Denmark; Steno Diabetes Center Aarhus, Aarhus University Hospital, 8200, Denmark.
  • 4. Department of Clinical Medicine, Aarhus University, Aarhus, 8000, Denmark; Department of Molecular Medicine, Aarhus University Hospital, Aarhus, 8200, Denmark.
  • 5. Université Paris Cité, CNRS, Inserm, Institut Cochin, Paris, 75014, France.
  • 6. Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, 2200, Denmark. Electronic address: [email protected].
PMID: 41325841 DOI: 10.1016/j.molmet.2025.102294
Abstract

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.

Keywords
AICAR; AMP-activated protein kinase; Glucose uptake; MK-8722; Single nucleus RNA sequencing.