科研之友
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摘要
IFN gamma signaling in endothelial (EC) and smooth muscle cells (SMC) is a key culprit of pathologic vascular remodeling. The impact of NF-kappa B inhibitory protein A20 on IFN gamma signaling in vascular cells remains unknown. In gain-and loss-of-function studies, A20 inversely regulated expression of IFN gamma-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 Ifn gamma-dependent genes. Transcriptome analysis of the aortic media from A20 heterozygote versus wild-type mice revealed increased basal Ifn beta signaling as the likely cause for higher Stat1 transcription. We confirmed higher basal IFN beta levels in A20-silenced human SMC and showed that neutralization or knockdown of IFN beta abrogates heightened STAT1 levels in these cells. Upstream of IFN beta, A20-silenced EC and SMC demonstrated higher levels of phosphorylated/activated TANK-binding kinase-1 (TBK1), a regulator of IFN beta transcription. This suggested that A20 knockdown increased STAT1 transcription by enhancing TBK1 activation and subsequently basal IFN beta levels. Altogether, these results uncover A20 as a key physiologic regulator of atherogenic IFN beta/STAT1 signaling. This novel function of A20 added to its ability to inhibit nuclear factor-kappa B (NF-kappa B) activation solidifies its promise as an ideal therapeutic candidate for treatment and prevention of vascular diseases. In light of recently discovered A20/TNFAIP3 (TNF alpha-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.
- 出版日期2014-11-7
