Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are emerging worldwide epidemics, projected to become the leading cause of liver transplants. The strongest genetic risk factor for NAFLD/NASH susceptibility and progression is a single-nucleotide polymorphism (SNP) in the patatin-like phospholipase domain-containing 3 gene (PNPLA3), rs738409, encoding the missense mutation I148M. This aminoacidic substitution interferes with the normal remodeling of lipid droplets in hepatocytes. It is also thought to play a key role in promoting liver fibrosis by inhibiting the release of retinol from hepatic stellate cells. Reducing PNPLA3 levels in individuals homozygous for 148M may be an effective treatment for the entire spectrum of NAFLD, based on gene dosage analysis in the human population, as well as the protective effect of another naturally occurring SNP (rs2294918) in PNPLA3 which, when co-inherited, reduces PNPLA3 mRNA levels to 50% and counteracts disease risk. By screening a clinical compound library targeting specific signaling pathways active in primary human hepatocytes, we identified momelotinib, a drug evaluated in clinical trials to treat myelofibrosis, as a potent down-regulator of PNPLA3 expression, across all genotypes. We found that momelotinib treatment yielded >80% reduction in PNPLA3 mRNA in human primary hepatocytes and stellate cells, as well as in vivo via acute and chronic treatment of WT mice. Using a human multilineage 3D spheroid model of NASH homozygous for the PNPLA3 mutant protein, we additionally show that it decreases PNPLA3 mRNA as well as intracellular lipid content. Furthermore, we show that the effects on PNPLA3 coincide with changes in chromatin accessibility within regulatory regions of the PNPLA3 locus, consistent with inhibition occurring at the level of transcription. In addition to its primary reported targets, the JAK kinases, momelotinib inhibits several non-JAK kinases, including ACVR1. Using a combination of targeted siRNA knockdowns and signaling pathway perturbations, we show that momelotinib reduces the expression of the PNPLA3 gene largely through the inhibition of BMP signaling rather than the JAK/STAT pathway. Overall, our work identified momelotinib as a potential NASH therapeutic and uncovered previously unrecognized connections between signaling pathways and PNPLA3. These pathways may be exploited by drug modalities to “tune down” the level of gene expression, and therefore offer a potential therapeutic benefit to a high at-risk subset of NAFLD/NASH patients.

Regulation of the terminal phase of the complement component pathway is a clinically validated approach for the therapeutic treatment of complement disorders. Inhibition of complement activation at the C5 level with the monoclonal antibody eculizumab has successfully been used for the treatment of rare disorders such as PNH and aHUS. However, even in these settings there remains a continued unmet need primarily due to need for intravenous administration, lack of activity in patients with C5 mutations and lack of universal access. Ra Pharmaceuticals has developed a macrocyclic synthetic peptide, RA101495, which binds complement C5 with subnanomolar affinity and allosterically inhibits its cleavage into C5a and C5b upon activation of the classical, alternative or lectin pathways. In vitro studies also demonstrated that RA101495 is capable of preventing MAC assembly after thrombin mediated complement activation and is a potent disruptor of the interaction in between C5b and C6. Inhibition of complement activity was evaluated in cynomolgus monkeys following single- and multi-dose subcutaneous (SC) administration. RA101495 exhibited high SC bioavailability and low, single doses fully inhibited complement-mediated hemolytic activity (>95%). Repeat dosing was well tolerated in monkeys and rats at high multiples of the projected human therapeutic dose and resulted in sustained and predictable inhibition of complement activity. RA101495 fully inhibited the hemolysis of erythrocytes from PNH patients after activation of the alternative pathway. The synthetic peptide offers a novel therapeutic approach for inhibiting C5 for the treatment of disorders caused by or associated with complement dysregulation. As a product designed for convenient self-administration, RA101495 should provide an attractive option over monoclonal antibody therapy for patients with PNH and aHUS, including those with C5 polymorphisms and other complement disorders, especially those associated with hypercoagulable states. Disclosures Ricardo: Ra Pharmaceuticals: Employment. Arata:Ra Pharmaceuticals: Employment. DeMarco:Ra Pharmaceuticals: Employment. Dhamnaskar:Ra Pharmaceuticals: Employment. Hammer:Ra Pharmaceuticals: Employment. Fridkis-Hareli:Ra Pharmaceuticals: Consultancy. Rajagopal:Ra Pharmaceuticals: Employment. Seyb:Ra Pharmaceuticals: Employment. Tang:Ra Pharmaceuticals: Employment. Tobe:Ra Pharmaceuticals: Employment. Treco:Ra Pharmaceuticals: Employment.

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