# Novel Strategy for Enhancing miRNA As A Therapeutic for Cardiac Regeneration

> **NIH NIH R01** · DUKE UNIVERSITY · 2020 · $397,500

## Abstract

Repair and regeneration of the injured heart with new, functional cardiomyocytes remains a daunting challenge
for cardiovascular medicine. Following cardiac injury, fibroblasts enter injury zone and through various
processes actively impair contractile function. Converting cardiac fibroblasts within scar tissue into functional
cardiomyocytes is a therapeutic approach that has great potential to restore the function of an injured heart.
We were the first to identify a combination of miRNAs, miR combo (miR-1, miR-133a, miR-208a, and miR-499-
5p) that directly reprogrammed cardiac fibroblasts into cardiomyocytes, whereas others have used
transcription factors to the same effect. Importantly, delivery of miR combo using lentivirus or retrovirus led to a
modest, but significant, improvement in cardiac function. This application is focused on improving miR combo
as a therapeutic by identifying ways to enhance efficiency, cell specificity, and effectiveness. Preliminary
studies have identified an Adeno-associated virus (AAV) serotype that specifically targets fibroblasts and,
moreover, displays enhanced transduction efficiency in vivo. Furthermore, TLR3 activation, which strongly
augments miR combo directed reprogramming in vitro, may be a novel way to increase effectiveness. Finally,
several transcriptional inhibitors have been identified as miR combo targets. These transcriptional inhibitors
repressed the expression of key cardiac transcription factors, suggesting a mechanism for miR combo directed
reprogramming. Three overlapping areas will be investigated in this project. Aim 1 will focus on optimizing the
efficiency, effectiveness, and cell specificity of miR combo in vitro. To that end we will test if the self-
complementary (sc)AAV 2/1 expressing a polycistronic miR combo results in the fibroblast-specific delivery of
miR combo. Pharmacological agents will define the appropriate level and duration of TLR3 activation for
optimal enhancement of miR combo mediated reprogramming. Aim 2 will address the same questions in vivo.
Speckle tracking echocardiography will determine changes in regional wall motion in vivo. Histology will
quantify fibrosis levels and lineage tracing will evaluate reprogramming of fibroblasts into cardiomyocytes.
Pharmacological agents will be used to determine if TLR3 activation enhances the functional improvements
that follow fibroblast reprogramming by miR combo. Aim 3 will define the mechanism by which miR combo
promotes reprogramming. Gain- and loss-of-function approaches will determine the role of the transcriptional
repressors in miR combo directed reprogramming. Luciferase assays will be used to delineate the physical
interaction between the miRNAs within miR combo and the transcriptional repressors. Decoy inhibitor
approaches will define the role of NFB, the key transcription factor in the TLR3 pathway, in miR combo
directed reprogramming.
Findings from these studies will provide important new insights into improving ...

## Key facts

- **NIH application ID:** 9840927
- **Project number:** 5R01HL131814-04
- **Recipient organization:** DUKE UNIVERSITY
- **Principal Investigator:** Victor J Dzau
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $397,500
- **Award type:** 5
- **Project period:** 2016-12-15 → 2020-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9840927

## Citation

> US National Institutes of Health, RePORTER application 9840927, Novel Strategy for Enhancing miRNA As A Therapeutic for Cardiac Regeneration (5R01HL131814-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9840927. Licensed CC0.

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