Targeted gene silencing of TLR4 using liposomal nanoparticles for preventing liver ischemia reperfusion injury.

RNAi-based therapy is a promising strategy for the prevention of ischemia-reperfusion injury (IRI). However, systemic administration of small interfering RNA (siRNA) may cause globally nonspecific targeting of all tissues, which impedes clinical use. Here we report a hepatocyte-specific delivery system for the treatment of liver IRI, using galactose-conjugated liposome nanoparticles (Gal-LipoNP). Heptocyte-specific targeting was validated by selective in vivo delivery as observed by increased Gal-LipoNP accumulation and gene silencing in the liver. Gal-LipoNP TLR4 siRNA treatment resulted in a significant decrease of serum alanine transferase (ALT) and aspartate transaminase (AST) in a hepatic IRI model. Histopathology displayed an overall reduction of the injury area in the Gal-LipoNP TLR4 siRNA treated mice. Additionally, neutrophil accumulation and lipid peroxidase-mediated tissue injury, detected by MPO, MDA and ROS respectively, were attenuated after Gal-LipoNP TLR4 siRNA treatment. Moreover, therapeutic effects of Gal-LipoNP TLR4 siRNA were associated with suppression of the inflammatory cytokines IL-1 and TNF-α. Taken together, this study is the first demonstration of liver IRI treatment using liver-specific siRNA delivery. © 2011 The Authors Journal compilation