ABSTRACT
Liver fibrosis affects millions of people worldwide and is rising vastly over the past decades. With no viable therapies available, liver transplantation is the only curative treatment for advanced diseased patients. Excessive accumulation of aberrant extracellular matrix (ECM) proteins, mostly collagens, produced by activated hepatic stellate cells (HSCs), is a hallmark of liver fibrosis. Several studies have suggested an inverse correlation between collagen-I degrading matrix metalloproteinase-1 (MMP-1) serum levels and liver fibrosis progression highlighting reduced MMP-1 levels are associated with poor disease prognosis in patients with liver fibrosis. We hypothesized that delivery of MMP-1 might potentiate collagen degradation and attenuate fibrosis development. In this study, we report a novel approach for the delivery of MMP-1 using MMP-1 decorated polymersomes (MMPsomes), as a surface-active vesicle-based ECM therapeutic, for the treatment of liver fibrosis. The storage-stable and enzymatically active MMPsomes were fabricated by a post-loading of Psomes with MMP-1. MMPsomes were extensively characterized for the physicochemical properties, MMP-1 surface localization, stability, enzymatic activity, and biological effects. Dose-dependent effects of MMP-1, and effects of MMPsomes versus MMP-1, empty polymersomes (Psomes) and MMP-1 + Psomes on gene and protein expression of collagen-I, MMP-1/TIMP-1 ratio, migration and cell viability were examined in TGFß-activated human HSCs. Finally, the therapeutic effects of MMPsomes, compared to MMP-1, were evaluated in vivo in carbon-tetrachloride (CCl4)-induced early liver fibrosis mouse model. MMPsomes exhibited favorable physicochemical properties, MMP-1 surface localization and improved therapeutic efficacy in TGFß-activated human HSCs in vitro. In CCl4-induced early liver fibrosis mouse model, MMPsomes inhibited intra-hepatic collagen-I (ECM marker, indicating early liver fibrosis) and F4/80 (marker for macrophages, indicating liver inflammation) expression. In conclusion, our results demonstrate an innovative approach of MMP-1 delivery, using surface-decorated MMPsomes, for alleviating liver fibrosis.