12 | In vitro study emulating muscle response to stimuli exploiting 3D tissue model

Elena Guarnaccia, R. Deodati, F. De Paolis, B. Corci, S. Bernardini, C. Fuoco, C. Gargioli | Dept. of Biology, University of Tor Vergata, Rome, Italy.

Abstract

Understanding muscle responses to external stimuli is critical for advancing therapeutic strategies and vaccine delivery, yet human-based models remain limited. To emulate muscle responses to immunological and delivery-related stimuli in vitro, we developed a human 3D muscle-like tissue model coupled with peripheral blood mononuclear cells (PBMCs). Upon exposure to immunostimulatory agents, the system supported the recruitment and modulation of antigen-presenting cells, including monocytes and macrophages, while stromal elements promoted dendritic cell expansion and activation. PBMCs exhibited an early innate immune signature (encompassing IL-15, IL-6, TNF-α, IFN-γ, IP-10, MCP-1, and IFN-inducible genes) reflecting immune activation profiles relevant for protective responses. Muscle-resident cells fostered an immunostimulatory environment, while the stromal compartment enhanced IFN-related mediator expression, demonstrating the platform’s capability to investigate muscle-immune system interactions under controlled conditions. To further explore muscle responses to delivery stimuli, we assessed the internalization and modulatory effects of solid lipid nanoparticles (SLN) and poly(lactic-co-glycolic acid) (PLGA) nanoparticles within the 3D muscle constructs. Both nanoparticle types were progressively internalized by myofibers, exhibiting distinct localization and accumulation near nuclei. Additionally, we tested the capability of SLN and PLGA nanoparticles to modulate inflammatory cytokines (IL-1β, IL-6, TNF-α) under inflammatory stimulation, indicating their potential for controlled delivery and local immune modulation within muscle tissue. In summary, this human 3D muscle-based in vitro model effectively emulates muscle responses to immunological and delivery stimuli, offering a versatile platform to study muscle immunobiology and evaluate advanced delivery strategies, while reducing the reliance on animal models in preclinical research.