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A novel anti‐inflammatory signaling role for the deubiquitinase USP20 in vivo (1065.5)
Author(s) -
JeanCharles PierreYves,
Zhang Lisheng,
Han Sangoh,
Kommaddi Reddy,
Wu JiaoHui,
Freedman Neil,
Shenoy Sudha
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.1065.5
Subject(s) - ubiquitin , deubiquitinating enzyme , tlr4 , chemistry , microbiology and biotechnology , in vivo , signal transduction , phosphorylation , iκbα , receptor , nf κb , ubiquitin ligase , biology , biochemistry , gene
The pro‐inflammatory Toll‐like receptor‐4 (TLR4) signals via Lys63‐linked autoubiquitination of TRAF family E3 ligases, which effect ubiquitin‐dependent activation of NFκB. In vascular smooth muscle cells (SMCs), we found TLR4 activation by LPS induced Lys63 polyubiquitination of the endocytic/signaling adaptor β‐arrestin2 (βarr2), which regulates NFκB. In co‐IP from intact cells, endogenous ubiquitin‐specific protease‐20 (USP20) associated with βarr2 and TRAF6. To determine if USP20 regulates these proteins in vivo, we created mice with SMC‐specific expression of WT‐USP20 or dominant‐negative (DN)‐USP20. In SMCs from these mice, LPS induced activation of NFκB (assessed by Ser536‐phosphorylation of p65) was 4‐fold greater in DN‐USP20‐Tg than in WT‐USP20‐Tg and non‐Tg control SMCs. Furthermore, Lys63 ubiquitination of both βarr2 and TRAF6 was augmented in DN‐USP20‐Tg SMCs. Congruently, 4 wk after endothelial denudation injury, carotid arteries of SMC‐DN‐USP20‐Tg mice showed 1.8‐fold greater NFκB activation (phospho‐p65Ser536) and 2.6‐fold greater neointimal hyperplasia (comprising proliferating SMCs) than non‐Tg or SMC‐WT‐USP20 mice (p<0.01)_even though all groups had equivalent carotids at baseline. Thus, USP20 seems to function as an anti‐inflammatory deubiquitinase by inhibiting ubiquitin‐dependent activation of β‐arrestin2, TRAF6 and NFκB in SMCs. Grant Funding Source : Supported by T32 HL007101 (PJYC), HL77185 (NJF) and HL080525 (SKS)