Human Serum Albumin-TRAIL Conjugate for the Treatment of Rheumatoid Arthritis

Albumin conjugation is viewed as an effective means of protracting short in vivo lifespans of proteins and targeting rheumatoid arthritis (RA). In this study, we present a human serum albumin (HSA) conjugate linked with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) via a bifunctional PEG derivative (HSA-TRAIL). Prepared HSA-TRAIL was found to have a larger molecular size (similar to 240 kDa, 15.4 nm) than TRAIL (similar to 66 kDa, 6.2 nm), and its bioactivity (apoptosis, cytotoxicity, and antiproliferation) was well preserved in Mia Paca-2 cells and mouse splenocytes. The enhanced therapeutic efficacy of HSA-TRAIL was demonstrated in collagen-induced arthritis (CIA) mice. The incidence and clinical scores, expressed as degree of erythema and swelling in HSA-TRAIL-treated mice, were remarkably lower than those of TRAIL-treated mice. The serum levels of pro-inflammatory cytokines IFN-gamma, TNF-alpha, IL-1 beta, and IL-2 in HSA-TRAIL-treated mice were significantly lower than those of TRAIL-treated mice. Furthermore, HSA-TRAIL accumulated in the hind paws of CIA mice, not in naive TRAIL mice. Pharmacokinetic profiles of HSA-TRAIL were greatly improved in comparison to those of TRAIL (AUC(inf): 844.1 +/- 130.0 vs 36.0 +/- 1.2 ngh/mL; t(1/2:) 6.20 +/- 0.72 vs 0.23 +/- 0.01 h, respectively). The HSA-TRAIL conjugate, which presents clear advantages of targeting RA and long systemic circulation by HSA and unique anti-inflammatory efficacy by TRAIL, has potential as a novel treatment for rheumatoid arthritis.