# Chemogenetic approaches to define the roles of redox dysfunction in the cardiomyopathy of aging

> **NIH NIH R21** · BRIGHAM AND WOMEN'S HOSPITAL · 2020 · $216,640

## Abstract

This R21 application proposes experiments that will develop and validate new models of
aging-related cardiac pathology by using chemogenetic approaches to generate redox stress in
the heart and other tissues. The development of an “age-related cardiomyopathy”– associated
with both systolic and diastolic cardiac dysfunction, redox stress, and a high mortality rate–
has been extensively documented. We have recently developed a new chemogenetic
approach that leads to the development of cardiomyopathy that is directly and specifically
caused by inducing an increase in redox stress in the heart. In the proposed studies, we will
examine this new cardiomyopathy model in the context of aging. We used a cardiotropic
adeno-associated virus serotype 9 (AAV9) to express a yeast D-amino acid oxidase (DAAO)
that selectively generates ROS in cardiac myocytes in vivo, causing redox stress in the heart
and leading to dilated cardiomyopathy. DAAO is a stereospecific enzyme that generates
hydrogen peroxide (H2O2) only when D-amino acids are available as substrate. Since most
mammalian tissues contain only L-amino acids, the yeast DAAO is inactive until D-amino
acids are provided. We injected recombinant DAAO-AAV9 virus into mice (or rats), and used
cellular imaging methods to show that H2O2 is robustly generated in cardiac myocytes only
after adding D-alanine to myocytes. We then developed an in vivo chemogenetic model to
generate chronic redox stress in the heart: we added D-alanine to the drinking water of mice
that had been infected with recombinant DAAO-AAV9. Compared to control animals, the
DAAO-AAV9-infected mice develop a dilated cardiomyopathy within 3 weeks of D-alanine
treatment. We propose to extend these approaches to study the roles of redox stress in
age-associated cardiomyopathy by infecting middle-aged and elderly mice with
recombinant DAAO-AAV9, and then analyzing physiological, metabolic, biochemical,
transcriptomic, and proteomic characteristics using both in vivo and ex vivo
approaches. These experiments are likely to identify new therapeutic targets to prevent or
treat the age-associated cardiomyopathy. We also propose to develop DAAO-TGLoxP
transgenic mouse lines that will permit analyses of tissue-specific redox stress in aging
using Cre-Lox methodologies to express DAAO in the heart and other tissues. We
anticipate that tissue-specific transgenic expression of DAAO will provide new
mechanistic insights into the broad range of disease states in which age-associated
tissue pathology is associated with redox dysfunction.

## Key facts

- **NIH application ID:** 9922852
- **Project number:** 5R21AG063073-02
- **Recipient organization:** BRIGHAM AND WOMEN'S HOSPITAL
- **Principal Investigator:** Thomas Michel
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $216,640
- **Award type:** 5
- **Project period:** 2019-04-15 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9922852

## Citation

> US National Institutes of Health, RePORTER application 9922852, Chemogenetic approaches to define the roles of redox dysfunction in the cardiomyopathy of aging (5R21AG063073-02). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/9922852. Licensed CC0.

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