Targeted silencing of CLYBL with platelet-mimetic siRNA nanoparticles drives itaconate-mediated macrophage reprogramming and protects against sepsis-triggered lung cell death.

Excessive inflammation and metabolic dysregulation fuel alveolar cell death in sepsis-induced lung injury, yet effective molecular interventions are lacking. We identify citrate lyase beta-like (CLYBL) as a previously unrecognized metabolic driver of macrophage-mediated tissue damage. In a murine cecal ligation and puncture model, CLYBL was strongly upregulated in lung tissue and peritoneal macrophages. To therapeutically target this pathway, we engineered platelet-derived extracellular vesicle-coated poly(lactic-co-glycolic acid) nanoparticles (PEVs@PLGA) encapsulating CLYBL-specific small interfering RNA. This platelet-mimetic system enabled efficient, biocompatible delivery of siRNA and robust CLYBL knockdown both in vitro and in vivo. CLYBL silencing triggered accumulation of the anti-inflammatory metabolite itaconate, limited M1 macrophage polarization, and preserved alveolar epithelial integrity, thereby reducing cell death and improving pulmonary repair. Transcriptomic analysis revealed broad immunometabolic remodeling consistent with enhanced resolution of inflammation. Biosafety evaluation confirmed negligible systemic toxicity. These findings uncover CLYBL as a critical metabolic checkpoint linking macrophage activation to alveolar cell death and highlight platelet-mimetic siRNA nanoparticles as a potent therapeutic strategy. Our work provides a mechanistic and translational framework for targeting macrophage immunometabolism to prevent fatal organ damage during sepsis. PEVs@PLGA@si-CLYBL promote itaconate accumulation, induce immune cell functional remodeling, and facilitate lung epithelial repair, offering a novel therapeutic approach for sepsis-induced lung injury (Created with BioRender.com).