# Competitive macrophage microRNA-RNA binding protein interactions in wound repair

> **NIH NIH R01** · YALE UNIVERSITY · 2020 · $322,438

## Abstract

Inadequate wound healing, resulting in chronic wounds, is a major and increasing U.S. health problem, due to
the rising incidence of diabetes and our aging population. Innate immune responses to tissue injury are critical
to wound repair. Monocyte/macrophages, both recruited and tissue-resident, secrete factors that are critical
mediators of the early proliferative and regenerative wound healing phases. Little attention has been paid to
posttranscriptional regulatory influences on gene expression in wound localized macrophages. This is a major
checkpoint in macrophage-dependent wound repair, since a majority of influential macrophage-derived
products are encoded by mRNAs that bear both AU-rich elements (AREs) and numerous microRNA (miRNA)
binding sites in their 3'-untranslated region (3'UTR). That is, a transcriptional activation trigger is often
insufficient for adequate gene expression. In particular, RNA-binding proteins (RBPs) protect vulnerable
3'UTRs from miRNA binding and consequent translational arrest (and/or mRNA degradation). We have
recently demonstrated that macrophage β2 integrin engagement results in dynamic modulation of the RBP
HuR, which protects numerous 3'UTR ARE-bearing mRNAs from degradation or translation blocks. We have
shown that macrophage HuR gene-deleted mice have repair defects in multiple wound models. In dynamic
fashion, HuR has the ability to relieve miRNA-mediated gene expression constraints. Our hypothesis is that
expression of a set of wound healing-promoting genes, both overlapping and distinct in recruited vs. tissue-
resident macrophages, is driven by HuR-dependent release of miRNA-mediated translation blocks. We have
generated unique, macrophage-specific translational profiling tools, and now propose to: (1) document the
presence of candidate, and define novel, macrophage mRNAs undergoing active, HuR-dependent translation
in early wound healing responses, using the Translating Ribosome Affinity Purification (TRAP) assay, with
pulldowns of the ribosomal fusion protein L10a-EGFP, expressed in myeloid cell-specific fashion, in HuR wild-
type or gene-deleted mice; (2) define miRNAs that target those TRAP-defined mRNAs, with biotin-3'UTR
riboprobe pulldowns of FACS-sorted L10a-EGFP+, wound localized macrophage extracts, confirming their
translation-repressing effects in dual luciferase 3'UTR reporter assays; and (3) release the miRNA-mediated
translational constraint on wound healing-promoting mRNAs, topically applying miRNA target site blocker
oligonucleotides which interfere with binding to specific mRNA 3'UTR target sites, in dorsal full thickness
excisional and ear punch hole wound models, assessing wound area, re-epithelialization, revascularization and
fibroblast repopulation. These molecular and preclinical approaches, directed at a gene expression regulatory
switch in wound-responsive macrophages, will provide mechanistic insight with therapeutic implications.

## Key facts

- **NIH application ID:** 10001549
- **Project number:** 5R01GM126412-04
- **Recipient organization:** YALE UNIVERSITY
- **Principal Investigator:** JEFFREY R. BENDER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $322,438
- **Award type:** 5
- **Project period:** 2017-09-20 → 2021-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10001549

## Citation

> US National Institutes of Health, RePORTER application 10001549, Competitive macrophage microRNA-RNA binding protein interactions in wound repair (5R01GM126412-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10001549. Licensed CC0.

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