# Discovery of novel therapeutic targets for NASH through deep phenotyping of human knockouts and mechanistic studies

> **NIH NIH R01** · COLUMBIA UNIVERSITY HEALTH SCIENCES · 2022 · $677,927

## Abstract

The progression of nonalcoholic fatty liver disease (NAFLD) to fibrotic non-alcoholic steatohepatitis (NASH) is
emerging as the leading cause of liver disease. Until mid-2021, the genetic etiology of NAFLD/NASH in humans has
been limited to a handful of loci. To address this gap, we and others have recently identified 657 novel loci associated
with several quantitative traits linked with NAFLD/NASH. While these new and prior discovery studies have
established secure links between genetic loci and NAFLD/NASH risk, a number of uncertainties continue to exist
about such findings, including: (a) the causal gene(s) at these loci; (b) the directional impact of these loci on disease
risk; and (c) the biological mechanisms leading to disease risk. Moreover, all prior discovery efforts have been limited
to: (d) common variant discovery platforms; (e) populations of European descent; and (f) use of proxy definitions of
NAFLD/NASH based on AST and ALT levels. We aim to resolve these uncertainties and find loci of high therapeutic
relevance by capitalizing on the Pakistan Genomic Resource (PGR), that has leveraged high levels of consanguinity
in Pakistan and assembled the largest cohort of human knockouts (KOs) in the world and a cohort of 4,000
ultrasonography (USG)-confirmed NAFLD cases. Specifically, in Aim 1, we will: (i) perform multi-ethnic association
analyses for rare and common variants in 700,000 participants (PGR + UK Biobank) for serum AST and ALT levels
and conduct validation studies in 4,000 USG-confirmed NAFLD cases and 4,000 controls; (ii) conduct fine-mapping
studies and colocalization analyses; (iii) perform rare variant gene burden tests, focusing on predicted loss of
function (pLoF) and predicted damaging variants (pDM) variants; (iv) conduct pathway analyses and (v) for 10 highly
prioritized loci, conduct call-back studies of pLoF carriers, along with their family members, to drive causal gene
identification and translation. In Aim 2, we will investigate two high priority genes already identified from the analyses
proposed in Aim 1, WWP2 and CASP8, to illustrate how such genes can be studied mechanistically and in
experimental NASH. For WWP2, we hypothesized based on its E3 ligase activity that it is protective by down-
regulating a key protein in fibrotic NASH, TAZ (WWTR1), which is now supported by our exciting preliminary in vitro
and in vivo data. CASP8 is an example of a NASH-promoting gene based on data from Aim 1 and prior mouse
studies, but the mechanisms are uncertain and likely not related to its canonical cell-death function. Here we will test
the hypothesis that PGR pLoF/pDM variants at WWP2 and CASP8, when introduced into hepatocytes of mice
lacking the endogenous genes, affect NASH as predicted from the human data and our hypotheses. We will also
probe the 2 genes' mechanisms in vitro and in experimental NASH and how the mechanism is affected by pLoF/pDM
variants. In Aim 3, we will investigate impact of genetic loci on dise...

## Key facts

- **NIH application ID:** 10504666
- **Project number:** 1R01DK133694-01
- **Recipient organization:** COLUMBIA UNIVERSITY HEALTH SCIENCES
- **Principal Investigator:** Danish Saleheen
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $677,927
- **Award type:** 1
- **Project period:** 2022-09-15 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10504666

## Citation

> US National Institutes of Health, RePORTER application 10504666, Discovery of novel therapeutic targets for NASH through deep phenotyping of human knockouts and mechanistic studies (1R01DK133694-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10504666. Licensed CC0.

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