# A new humanized mouse model to study HBV gene editing

> **NIH NIH R01** · FRED HUTCHINSON CANCER CENTER · 2024 · $862,440

## Abstract

Project Summary
Chronic Hepatitis B virus (HBV) infection (CHB) affects hundreds of millions of people across
the world. Despite effective vaccines, and antiviral therapies that can suppress viral replication,
these infections are largely incurable, and new therapies for CHB are desperately needed. We
have investigated gene editing using targeted nucleases to cleave covalently closed circular
DNA (cccDNA), the template for HBV replication, which results in its degradation or inactivation
in infected hepatocytes. Our work and the work of others has been hindered due to the fact that
existing small animal models for HBV have substantial limitations, or are complex and
expensive to establish. To this end, we established and validated a robust and low-cost liver
humanized NSG-PiZ mouse as a model for the study of HBV. Here we propose to use these
mice for the evaluation of novel curative gene editing therapies that target CHB.
 Specific Aim 1. Evaluate the anti-HBV efficacy of HBV gene therapy in liver-humanized
NSG-PiZ mice. We will first evaluate the efficiency of HBV gene editing in NSG-PiZ mice, using
AAV-SaCas9 vectors we previously validated in HBV-infected humanized FRG mice. We will
then compare lipid nanoparticle (LNP) delivery of nuclease mRNA with AAV vectors for the
transduction of PHH in our model. We will compare the antiviral efficacy of different classes of
gene editing nuclease in our NSG-PiZ mouse model of CHB, and evaluate chromatin modifying
agents for their ability to make cccDNA accessible to gene editing nucleases in vitro and in vivo.
Finally, we will assess combined gene-editing, reverse transcriptase inhibitor (RTi), and entry
inhibitor antiviral therapy in our model of CHB.
 Specific Aim 2. Evaluate the tolerability and host genomic consequences of AAV- and
LNP-delivered nuclease therapies targeting HBV in liver-humanized NSG-PiZ mice. We will first
determine the maximum tolerated dose (MTD) and minimal effective dose for AAV-nuclease
and LNP-nuclease therapies in our CHB model. We will then monitor the effects of different
nuclease classes on treatment-related off-target genotoxicity in vivo and determine whether use
of liver-specific promoters can mitigate therapy-associated genotoxicity. We will also determine
whether therapy-associated genotoxicity is reduced when nuclease expression is transiently
provided by LNPs. Finally, we will evaluate therapy-specific immune responses and therapy-
associated hepatotoxicity and neurotoxicity after transient or persistent nuclease expression in
immunocompetent mice.

## Key facts

- **NIH application ID:** 10981535
- **Project number:** 1R01AI175949-01A1
- **Recipient organization:** FRED HUTCHINSON CANCER CENTER
- **Principal Investigator:** KEITH R JEROME
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $862,440
- **Award type:** 1
- **Project period:** 2024-08-01 → 2029-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10981535

## Citation

> US National Institutes of Health, RePORTER application 10981535, A new humanized mouse model to study HBV gene editing (1R01AI175949-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10981535. Licensed CC0.

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