# Uncovering Molecular Targets for Arrhythmogenic Cardiomyopathy Therapeutics

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 2024 · $395,000

## Abstract

Abstract
Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an incurable genetic based cardiac
disease that causes sudden death in young adults and athletes. ARVD/C is termed a “disease of the
desmosome” as 40-50% of mutations in ARVD/C patients are found in desmosomal (junctional anchor) genes,
with plakophilin-2 (PKP2) being the most frequently mutated desmosomal gene. Evidence suggests that altered
RNA splicing may be a critical mechanism through which PKP2 patient genetics drive ARVD/C. However, no
models and limited mechanistic insights exist into how human desmosomal mutations in RNA splicing impact
ARVD/C and what form of therapeutics would be impactful in these settings. Through CRISPR-Cas9 we
generated a novel mouse model globally harboring a human PKP2 mutation (IVS10-1 G>C) that impacts RNA
splicing. PKP2 homozygous mutant (PKP2 Hom) mice selectively display all adult hallmarks of ARVD/C including
sudden death. RNA and sequencing analyses revealed low levels of a larger PKP2 transcript that retains an
intronic sequence. Protein analyses of PKP2 Hom hearts revealed low levels of a higher molecular weight PKP2
mutant protein that was expressed in the absence of endogenous PKP2. Strategies to increase wild type PKP2
and mutant PKP2 protein in PKP2 mutant neonatal cardiomyocytes suggested that splicing effects on PKP2
haploinsufficiency mechanistically drive cell junction deficits in early ARVD/C. Targeted restoration of PKP2
protein dose in neonatal PKP2 Hom mice had therapeutic potential in late ARVD/C as it restored cardiac
mechanical junction complex and prolonged life in adult PKP2 Hom mice. PKP2 Hom mice provide an ideal test
platform to assess the impact and mechanism of PKP2 restoration in circumventing ARVD/C in classic patient-
centric models during early and late stages of disease. Prime editing (search-and-replace) strategies have come
to age as novel methods to correct single base mutations and address the “root cause” of ARVD/C, though
limited studies have applied this technology towards therapeutic use in disease settings. We hypothesize the
PKP2 RNA splicing mutation is sufficient to drive ARVD/C through a mechanism impacting splicing
consequences on PKP2 protein dose. PKP2 targeted strategies (gene therapy and prime base editor-directed
correction) can be exploited to therapeutically alter ARVD/C. We aim to determine: (i) the pathogenic mechanism
by which PKP2 RNA splicing mutations drive ARVD/C, (ii) the impact and mechanism of early and late PKP2
restoration in our novel PKP2 mutant mouse and human ARVD/C models, and (iii) a base editing strategy to
correct the PKP2 (IVS10-1 G>C) mutation and assess its impact in our novel PKP2 mutant ARVD/C model.

## Key facts

- **NIH application ID:** 10814809
- **Project number:** 5R01HL162369-03
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **Principal Investigator:** Farah Sheikh
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $395,000
- **Award type:** 5
- **Project period:** 2022-04-01 → 2026-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10814809

## Citation

> US National Institutes of Health, RePORTER application 10814809, Uncovering Molecular Targets for Arrhythmogenic Cardiomyopathy Therapeutics (5R01HL162369-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10814809. Licensed CC0.

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