Tissue nanotransfection-mediated induction of neurogenic programs promotes myoprotective responses in denervated skeletal muscle

Abstract

Peripheral nerve injuries often result in prolonged skeletal muscle denervation, leading to progressive atrophy, fibrosis, neuromuscular instability, and loss of regenerative capacity before axons can reinnervate distal targets. Here, we developed a non-viral strategy using tissue nanotransfection (TNT) to deliver the neurogenic transcription factor cocktail Ascl1, Brn2, and Myt1l (ABM) directly to denervated skeletal muscle. In vitro, ABM-transfected myoblasts sustained expression of the reprogramming factors, acquired neuron-like morphologies, upregulated neuronal markers including Tuj1, Map2, and Syp, and exhibited electrophysiological properties consistent with membrane excitability. RNA sequencing confirmed broad activation of neurogenic transcriptional programs, with enrichment of pathways associated with neuronal fate commitment, neuron differentiation, axon guidance, synaptogenesis, and developmental signaling. In a mouse model of sciatic nerve transection, TNT enabled localized ABM expression in denervated gastrocnemius muscle. ABM-TNT treatment accelerated resolution of denervation-associated fibrillation potentials and showed trends toward improved twitch and tetanic torque, compound muscle action potential amplitudes, and muscle mass preservation. Transcriptomic profiling of treated muscles 5 weeks after injury revealed distinct gene expression programs enriched for muscle regeneration, neuromuscular organization, trophic support, extracellular matrix remodeling, angiogenesis, myogenesis, and metabolic adaptation. Network analyses further identified activation of neurogenic regulators, neurotrophic signaling, and vascular-support pathways. These findings establish TNT-mediated ABM delivery as a non-viral platform for inducing neurogenic and myoprotective programs in denervated muscle, suggesting a potential strategy to preserve muscle viability during the prolonged interval required for peripheral nerve regeneration.