Targeted Interleukin-22 Gene Delivery in the Liver by Poly-Metformin and Penetratin-Based Hybrid Nanoparticles to Treat Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) is now a leading cause of chronic liver disease, while there is currently no available treatment strategy. Interleukin-22 (IL-22) has been recognized as a promising agent for alleviating NAFLD, but the efficacy of IL-22 is far from satisfactory because safe dose of IL-22 elicited limited improvement while higher concentration might induce serious side effects and off-target toxicities. Thus, targeted and sustained expression of IL-22 in the liver is necessary. To meet the challenge, we elaborately developed a novel poly-metformin carrier by conjugating biguanide to chitosan, termed chitosan-metformin (CM), which could exert advanced gene delivery efficiency and possess intrinsic therapeutic efficacy from metformin for NAFLD. CM accompanied with penetratin and DSPE-PEG2000 could self-assemble to form stable nanocomplexes with IL-22 gene via electrostatic interaction. This nanoparticle (CDPIA) exerted desirable particle size at ~100 nm, fine morphology and efficient cellular internalization. Furthermore, CDPIA also demonstrated a unique superiority in endosomal escape capacity and satisfactory biocompatibility as well as predominant liver accumulation. Most importantly, CDPIA distinctly alleviated hepatic steatosis, restored insulin sensitivity and improved metabolic syndrome in high fat diet (HFD)-fed mice model. This liver targeted delivery of IL-22 activated STAT3/Erk1/2 and Nrf2/SOD1 signaling transductions as well as modulated lipid metabolic-related gene expression. These findings altogether demonstrated that the poly-metformin and penetratin-based hybrid nanoparticles could be exploited as a novel safe and efficient strategy for the improvement of NAFLD.