title: A20 regulates atherogenic interferon (IFN)-γ signaling in vascular cells by modulating basal IFNβ levels.
abstract: IFNγ signaling in endothelial (EC) and smooth muscle cells (SMC) is a key culprit of pathologic vascular remodeling. The impact of NF-κB inhibitory protein A20 on IFNγ signaling in vascular cells remains unknown. In gain- and loss-of-function studies, A20 inversely regulated expression of IFNγ-induced atherogenic genes in human EC and SMC by modulating STAT1 transcription. In vivo, inadequate A20 expression in A20 heterozygote mice aggravated intimal hyperplasia following partial carotid artery ligation. This outcome uniquely associated with increased levels of Stat1 and super-induction of Ifnγ-dependent genes. Transcriptome analysis of the aortic media from A20 heterozygote versus wild-type mice revealed increased basal Ifnβ signaling as the likely cause for higher Stat1 transcription. We confirmed higher basal IFNβ levels in A20-silenced human SMC and showed that neutralization or knockdown of IFNβ abrogates heightened STAT1 levels in these cells. Upstream of IFNβ, A20-silenced EC and SMC demonstrated higher levels of phosphorylated/activated TANK-binding kinase-1 (TBK1), a regulator of IFNβ transcription. This suggested that A20 knockdown increased STAT1 transcription by enhancing TBK1 activation and subsequently basal IFNβ levels. Altogether, these results uncover A20 as a key physiologic regulator of atherogenic IFNγ/STAT1 signaling. This novel function of A20 added to its ability to inhibit nuclear factor-κB (NF-κB) activation solidifies its promise as an ideal therapeutic candidate for treatment and prevention of vascular diseases. In light of recently discovered A20/TNFAIP3 (TNFα-induced protein 3) single nucleotide polymorphisms that impart lower A20 expression or function, these results also qualify A20 as a reliable clinical biomarker for vascular risk assessment.
authors.affiliation: From the Division of Vascular and Endovascular Surgery, Center for Vascular Biology Research and the Transplant Institute, Department of Surgery.
authors.forename: Herwig P
authors.initials: HP
authors.lastname: Moll
authors.affiliation: From the Division of Vascular and Endovascular Surgery, Center for Vascular Biology Research and the Transplant Institute, Department of Surgery.
authors.forename: Andy
authors.initials: A
authors.lastname: Lee
authors.affiliation: From the Division of Vascular and Endovascular Surgery, Center for Vascular Biology Research and the Transplant Institute, Department of Surgery.
authors.forename: Darlan C
authors.initials: DC
authors.lastname: Minussi
authors.affiliation: From the Division of Vascular and Endovascular Surgery, Center for Vascular Biology Research and the Transplant Institute, Department of Surgery.
authors.forename: Cleide G
authors.initials: CG
authors.lastname: da Silva
authors.affiliation: From the Division of Vascular and Endovascular Surgery, Center for Vascular Biology Research and the Transplant Institute, Department of Surgery.
authors.forename: Eva
authors.initials: E
authors.lastname: Csizmadia
authors.affiliation: the Division of Interdisciplinary Medicine and Biotechnology, Bioinformatics Core, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02135.
authors.forename: Manoj
authors.initials: M
authors.lastname: Bhasin
authors.affiliation: From the Division of Vascular and Endovascular Surgery, Center for Vascular Biology Research and the Transplant Institute, Department of Surgery, Division of Nephrology, Department of Medicine, and cferran@caregroup.harvard.edu.
authors.forename: Christiane
authors.initials: C
authors.lastname: Ferran
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry; D001011:Aorta / Q000473:pathology; D050197:Atherosclerosis / Q000378:metabolism*; D002465:Cell Movement; D003251:Constriction, Pathologic / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007249:Inflammation; D016899:Interferon-beta / Q000378:metabolism*; D007371:Interferon-gamma / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism* / Q000502:physiology*; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D020641:Polymorphism, Single Nucleotide; D034741:RNA, Small Interfering / Q000378:metabolism; D050794:STAT1 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D020298:U937 Cells
chemical_list: D000893:Anti-Inflammatory Agents; D004268:DNA-Binding Proteins; C573415:IFNG protein, human; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D016899:Interferon-beta; D007371:Interferon-gamma; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D003546:Cysteine Endopeptidases; C513261:Tnfaip3 protein, mouse
keywords: A20/TNFAIP3; Atherosclerosis; Biomarker; Endothelial Cell; Interferon; Signal Transducers and Activators of Transcription 1 (STAT1); TANK-binding Kinase 1 (TBK1); Vascular Remodeling; Vascular Smooth Muscle Cells