Engineered Long-Acting Irisin-Albumin Binding Domain Fusion Protein for Enhanced Anti-inflammatory Efficacy in Lipopolysaccharides-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 fusion protein to significantly extend its systemic circulation 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 the lipopolysaccharide (LPS)-induced mouse model of systemic inflammation, both Irisin and ABD-Irisin significantly reduced plasma TNF-alpha levels, splenomegaly, and histopathological inflammation. Notably, ABD-Irisin (500 ug/kg) demonstrated significantly enhanced suppression of plasma IL-6 and inflammatory cytokines (IL-1b, IL-10) compared to native Irisin. Single-cell RNA sequencing further revealed that ABD-Irisin robustly suppressed the activation of the TLR4-MYD88-NF-kB signaling axis in bone marrow immune cells, outperforming native 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.