# Regulation of Vascular Inflammatory Signaling by the Deubiquitinase USP20

> **NIH NIH R01** · DUKE UNIVERSITY · 2020 · $534,626

## Abstract

PROJECT SUMMARY
We recently demonstrated that ubiquitin-specific protease-20 (USP20) is scaffolded by the adaptor
protein known as β-arrestin2 (βarr2), and that USP20 desensitizes ubiquitin-dependent signaling from
Toll-like receptor-4 (TLR4) to NFκB activation by deubiquitinating TRAF6 and βarr2. Using transgenic
mice expressing dominant-negative USP20 in smooth muscle cells, we found that USP20 reduces
neointimal hyperplasia after arterial injury and that USP20 activity in SMCs reduces atherosclerosis in
Ldlr-/- mice. To establish anti-atherogenic effects of systemically expressed USP20, and to elucidate
further molecular mechanisms by which USP20 protects against atherosclerosis, this project will test
the hypothesis that USP20 attenuates atherosclerosis by deubiquitinating several substrate proteins
that were previously unassociated with USP20 but that are important in signaling pathways that activate
NFκB: βarr1, TRAF6, TRAF2, and RIPK1. Furthermore, because USP20 employs βarr2 as a scaffold
to facilitate association with distinct proteins, and because βarr1 reduces vascular inflammation, this
project will test whether USP20’s anti-atherogenic activity involves βarr1-mediated scaffolding. To
these ends, this project will study systemic effects of USP20 on atherosclerosis by comparing Usp20-/-
/Ldlr-/- versus Ldlr-/- mice, on a background of βarr1+/+ or βarr1-/+. To determine the effects of endothelial
USP20 on atherosclerosis, this project will compare atherosclerosis among VECad-Cre-
ERT2/Usp20flox/flox/Ldlr-/- vs. Usp20flox/flox/Ldlr-/- mice treated ± tamoxifen; furthermore, we will investigate
cytokine secretion, and dynamic ubiquitination of signaling proteins in primary aortic endothelial cells
that are WT, Usp20-/-, Usp20-/-/βarr1-/+, or βarr1-/-. To determine what kinase in endothelial cells
phosphorylates USP20 on Ser333 (and thereby abrogates USP20 deubiquitinase activity), this project
will test IRAK1, PAK1, and ROCK1 with several loss-of function approaches, including a USP20
minigene, in primary endothelial cells. These studies collectively may identify USP20 phosphorylation
as novel therapeutic target for atherosclerosis.

## Key facts

- **NIH application ID:** 9893026
- **Project number:** 5R01HL142286-02
- **Recipient organization:** DUKE UNIVERSITY
- **Principal Investigator:** NEIL J. FREEDMAN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $534,626
- **Award type:** 5
- **Project period:** 2019-03-15 → 2023-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9893026

## Citation

> US National Institutes of Health, RePORTER application 9893026, Regulation of Vascular Inflammatory Signaling by the Deubiquitinase USP20 (5R01HL142286-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9893026. Licensed CC0.

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