FGF4 sustained-release nano-liposomes attenuate heat stroke-induced MODS by suppressing ZBP1-mediated programmed necrosis

Heatstroke (HS) represents a life-threatening hyperthermic emergency that often leads to multiple organ dysfunction syndrome (MODS), yet no specific pharmacotherapy exists to interrupt this progression. Recent evidence has identified ZBP1-mediated programmed necrosis as a key contributor to organ failure in severe HS, highlighting the critical need for agents that can inhibit this pathway. This study aimed to investigate whether fibroblast growth factor 4 (FGF4) could mitigate HS-induced MODS and to clarify the underlying molecular mechanisms. Using complementary in vitro and in vivo models, along with gene knockdown, proximity ligation, and immunoprecipitation assays, this study indicates that FGF4 significantly reduces multi-organ injury caused by heat stress. Mechanistically, FGF4 interacts with its receptor to activate the AMPK signaling pathway, leading to the phosphorylation of HSF1 at Ser121, which impairs HSF1 nuclear translocation and transcriptional activity, ultimately decreasing ZBP1 expression and inhibiting ZBP1-dependent programmed necrosis. Given the short half-life of native FGF4, a major obstacle for clinical application, a sustained-release nano-liposomal formulation (FGF4-Nano) was engineered using DEPE-PEG2000. This nano-formulation maintains full bioactivity and demonstrates enhanced therapeutic efficacy in HS models, as evidenced by reduced tissue necrosis, improved liver and renal function, and diminished inflammatory damage. Collectively, this work positions FGF4 as a novel suppressor of ZBP1-mediated necrosis, elucidates the mechanistic basis for its actions, and introduces a nano-delivery strategy that significantly amplifies its anti-HS potential, setting the stage for a targeted therapeutic intervention in severe heatstroke.