Bioengineered extracellular vesicles escape lysosomal degradation and deliver Tet-PKM2 for macrophage immunometabolic...

Modulating macrophage phenotype and function via immunometabolic reprogramming represents a new therapeutic paradigm to combat chronic inflammatory diseases such as periodontitis. Tetrameric pyruvate kinase M2 (Tet-PKM2), a highly active metabolic enzyme involved in the flux of glucose-derived carbons into the tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS), was found to be dramatically decreased in response to inflammation, rendering a potential immunometabolic target for developping new therapeutics. Hence, we report a large extracellular vesicle (LEV) that is bioengineered to intracellularly deliver Tet-PKM2 for the reprogramming of proinflammatory macrophages and the restoration of their aberrant immunometabolism. We engineered Tet-PKM2-enriched LEVs modified by tannic acid (LEVs^Tet-PKM2@TA) that can intracellularly deliver Tet-PKM2 and increase their ability to escape lysosomal degradation for the intracellular delivery of Tet-PKM2. In vitro, LEVs^Tet-PKM2@TA were able to rescue aberrant pyruvate metabolism in lipopolysaccharide (LPS)-activated macrophages by increasing TCA cycle activity and enhancing mitochondrial OXPHOS metabolism. In vivo, LEVs^Tet-PKM2@TA exerted robust immunomodulatory effects by increasing pyruvate kinase (PK) activity and coaxing macrophages toward the M2 phenotype, ultimately resulting in robust periodontal tissue regeneration in a mouse ligature-induced periodontitis model. This study provides a versatile and safe method for the targeted delivery of Tet-PKM2 via EVs to modulate macrophage phenotype and function. Our work demonstrates a new concept for immunometabolic reprogramming to treat chronic inflammatory diseases.