Development and Preclinical Evaluation of Nanoformulations in Liver Fibrotic Mice

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PROJECT SUMMARY Liver injury from alcohol abuse, and obesity can lead to liver inflammation, steatosis, and fibrosis. Liver cell damage results in the release of inflammatory cytokines from hepatocytes and Kupffer cells (KCs), which cause the activation of hepatic stellate cells (HSCs). If unresolved, it may result in liver fibrosis and progression to cirrhosis. Hedgehog (Hh) signaling regulates multiple pathways in liver fibrosis, including epithelial-to- mesenchymal transition (EMT), HSC activation, and inflammation. Further, chronic liver diseases are associated with the dysregulation of miRNAs. Specifically, miR-96 is upregulated after liver damage and promotes fatty liver disease (FLD). miR-96 caused malfunctioning of insulin receptor (INSR) and insulin receptor substrate (IRS)-1 results in impaired insulin signaling and glycogen synthesis. Further, miR-96 downregulates SMAD7 and FOXO1-3 and promotes transforming growth factor-beta 1 (TGF-β1) mediated liver fibrosis. In our preliminary studies, we demonstrated the upregulation of Hh signaling ligands including PTCH1, SHH, and GLI2 cause significant increase in collagen and fat deposition in 5% ethanol and high-fat diet (HFD) fed mouse. We synthesized a novel Hh pathway inhibitor 2-chloro-N 1-[4-chloro-3-(2-pyridinyl) phenyl]-N4, N4-bis(2- pyridinylmethyl)-1,4-benzenedicarboxamide (MDB5) with GLI1/2 inhibitory activity in nanomolar (nM) concentration. Treatment of both HFD and alcohol-induced liver disease (ALD) mice with MDB5 resulted in a significant decrease in the levels of liver injury markers aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and further ablate GLI2, and its target genes. Our miRNA profiling in ALD and HFD mouse liver identified miR-96 was consistently upregulated. Target Scan analysis revealed that miR-96 targets several anti-inflammatory and anti-fibrogenic genes. The knockdown of miR-96 expression in hepatocytes and HSCs with anti-miR-96 resulted in the restoration of affected genes SMAD7 and FOXO3. We synthesized glycyrrhetinic acid (GA) conjugated GA-PEG-P(Asp)-g-DC-g-TEPA copolymers for liver-specific in vivo delivery of MDB5 and anti-miR-96, respectively. There was a significant increase in MDB5 concentration in the fibrotic liver at 1h post systemic administration of MDB5 loaded GA-NPs. TGF-β and Hh signaling crosstalk whereby TGF-β1 induces GLI-1 through downstream consequence of RAS signaling. Therefore, we hypothesize that the combination therapy of MDB5 and anti-miR-96 using GA-NPs could prevent alcohol and fat induced liver injury, and fibrosis. Our specific aims are to i) establish the therapeutic efficacy of the Hh inhibitor MDB5 on alcohol and high fat diet induced liver injury; ii) establish the profibrotic role of miR-96 in in HFD and ALD mouse models, and iii) determine the therapeutic efficacy of liver targeted NPs loaded with MDB5 and anti-miR-96 for treating HFD and ALD mouse models. Our long-term goal is to understand the progressive mechanisms of ALD and NAFLD to liver fibrosis, and establish new, liver-specific treatments.