Immunoregulatory protein-hybrid extracellular vesicles via self-loadable backbone cyclization for oral inflammatory bowel disease therapy

Despite the potential of extracellular vesicles (EVs) and therapeutic proteins as carriers and cargos for oral delivery, their precise functional integration remains a persistent challenge, thereby limiting synergistic therapeutic outcomes. Here, we present a protein-hybrid, orally delivered EV strategy that integrates naturally bioactive EVs with self-loadable, backbone-cyclized immunoregulatory proteins for inflammatory bowel disease (IBD) therapy. Through computationally guided design and split intein-mediated backbone cyclization, we generated cyclized variants of key immunoregulatory proteins with improved functionality. Among these, C-R₄-tagged cyclization of phosphatase domain of T-cell protein tyrosine phosphatase (ppTCPTP) improved membrane permeability, thermal stability, and anti-inflammatory activity. This backbone cyclization enabled efficient and high-capacity loading of ppTCPTP into native EVs that are not amenable to genetic engineering. Notably, these protein-hybrid EVs exhibited acidic resistance for oral delivery and synergistically enhanced antioxidant and anti-inflammatory effects in murine IBD organoids and <i>in vivo</i> colitis models, markedly reducing intestinal inflammation and restoring epithelial barrier integrity. Our findings highlight the translational potential of this self-loadable protein-EV platform as a safe and potent oral biologic for IBD therapy.