Functionally Mature Bioengineered Human Skeletal Muscle Tissues Capture Essential Aspects of Glucose Metabolism

Abstract

Human skeletal muscle is a major regulator of whole-body metabolic homeostasis, yet mechanistic insight into human muscle plasticity is limited by the lack of in vitro models with adult-like metabolic and functional maturity. Here, we develop a workflow for generating bioengineered human skeletal muscle tissues that undergo coordinated structural, molecular, and functional maturation and stabilize in an adult-like state by day 21. Time-resolved RNA-seq and protein profiling reveal consolidation of contractile programs alongside progressive metabolic maturation, including increased mitochondrial electron transport chain content, mature mitochondrial network organization, and upregulation of glucose- and glycogen-handling proteins as well as muscle-enriched AMPK isoforms. Functionally, the tissues develop physiological force-frequency behavior, post-tetanic potentiation, and reproducible fatigue responses that are exacerbated by hypoxia and glucose withdrawal. Exercise-like chronic stimulation increases force and endurance with hypertrophy-like remodeling, and these adaptations reverse with detraining. The model also captures pharmacological responsiveness. {beta}2-adrenergic stimulation activates canonical signaling, increases force, limits disuse-related decline, and improves endurance in a glucose-dependent manner. Under physiological insulin and IGF-1 conditions, tissues show robust insulin-stimulated glucose uptake and glycogen synthesis, with punctate glucose transporter 4 (GLUT4) localization. Finally, knockdown of muscle glycogen synthase (GYS1) preserves peak tetanic force but impairs endurance and force recovery under fuel stress, indicating that glycogen metabolism is a key determinant of human muscle resilience.