Abstract
The Specific Aim of this Phase I STTR proposal is to test the feasibility of treating non-alcohol steatohepatitis
(NASH) by increasing mitochondrial metabolism, which is the main pathway for lipid catabolism in the liver.
NASH is a stage of non-alcohol fatty liver disease (NAFLD) that has progressed to a pathological state. NASH
can lead to cirrhosis, leading to liver failure or hepatocellular carcinoma. NASH is especially common in those
with other metabolic disorders, such as obesity, diabetes, and/or hyperlipidemia, but also affects the healthy
population. About 30% of the population in US has NAFLD, with 5 million instances of NASH diagnosed each
year in the US with advanced fibrosis and about 1.8 million individuals progressed to cirrhosis. The primary
treatment for NASH is lifestyle change. However, few patients remain adherent for extended periods of time.
No drugs have been approved by the FDA for treating NASH. To address this need, we are developing an
siRNA-based drug to treat NASH by increasing liver metabolism. Fatty acids are transported to the liver where
they are metabolized through beta-oxidation coupled to the electron transport chain (ETC) in the mitochondria.
Increased mitochondrial respiratory activity in the liver could therefore speed up the degradation of fatty acids
and prevent their accumulation in the liver. A key regulator of the ECT is the MCJ protein (MCJ/DnaJC15 or
Methylation-Controlled J protein). MCJ is a mitochondrial protein that reduces respiration dependent ATP
levels. We have demonstrated that removal of MCJ activity is safe and results in increased mitochondrial
metabolism/ATP production. We have developed an siRNA formulation (siMCJ) that effectively removes
mouse MCJ in the liver. Using this formulation, we have shown in two mouse models that we can reverse or
prevent NASH pathologies. siRNA has been validated as a drug for number of diseases, including liver
diseases, with over 30 clinical trials having been run, thus validating the use of this therapeutic approach.
While our preliminary data are compelling thus far, the studies were carried out at only one dose of siRNA and
against the mouse MCJ protein. Thus, to show feasibility of our approach, prior to carrying out IND enabling
studies, we must carry out a more robust feasibility study that includes demonstration of safety, a dose/effect
relationship, and efficacy of human siMCJ. To this end, we will carry out the following Tasks:
Task 1: Evaluate efficacy and toxicity of mouse siMCJ in vivo using mouse models
Task 2: Evaluate efficacy human siMCJ in vivo using humanized-liver mouse model (KMT-Mice)
Test of Feasibility: We must observe findings in Task 1 that are similar to those in the preliminary study
section and we must observe a dose/effect curve that can be fit to a standard Hill type or log/logit analysis and
that covers the EC50 point of the curve. We must observe a TI (therapeutic index) of at least 3 (maximally
effective dose/MTD). This TI would indicate a very safe dosing window, since we use a maximally effective
dose as the numerator. Findings in Task 2 must also be similar to the findings in the preliminary study section.