Engineered long-acting Irisin-albumin binding domain fusion protein for enhanced anti-inflammatory efficacy in lipopolysaccharide-induced systemic inflammation.

Irisin is a peptide hormone with notable anti-inflammatory and metabolic regulatory effects but has limited clinical utility due to its extremely short plasma half-life (< 1 h). In this study, we engineered an albumin-binding domain (ABD)-conjugated Irisin (ABD-Irisin) fusion protein to significantly extend half-life and enhance therapeutic potency. ABD-Irisin fusion protein was successfully expressed in HEK-293F cells, purified, and validated through functional assays including lipid droplet reduction and western blot assays. Pharmacokinetic studies demonstrated that ABD-Irisin markedly prolonged the plasma half-life of Irisin to approximately 10 h, substantially surpassing native Irisin, and showed enhanced tissue distribution in vivo. In a lipopolysaccharide (LPS) induced mouse model of systemic inflammation, both Irisin and ABD-Irisin significantly reduced plasma TNF-α levels, splenomegaly, and histopathological inflammation. Notably, ABD-Irisin (500 μg/kg) demonstrated significantly enhanced suppression of plasma IL-6 and splenic inflammatory cytokines (IL-1β, IL-10) compared to native Irisin. Single-cell RNA sequencing further revealed that ABD-Irisin robustly suppressed the activation of the TLR4-MyD88-NF-κB signaling axis in bone marrow immune cells, outperforming unmodified Irisin. These findings demonstrate that ABD conjugation is an effective strategy to enhance the pharmacokinetics and anti-inflammatory efficacy of Irisin, highlighting ABD-Irisin as a promising therapeutic candidate for inflammatory diseases.