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Long non-coding RNAs (lncRNAs) have emerged as critical regulators in human disease including atherosclerosis. However, the mechanisms involved in the post-transcriptional regulation of the expression of disease-associated lncRNAs are not fully understood. Gene expression studies revealed that Nuclear Paraspeckle Assembly Transcript 1 (NEAT1) lncRNA expression was increased by >2-fold in peripheral blood mononuclear cells (PBMCs) derived from patients with coronary artery disease (CAD) or in carotid artery atherosclerotic plaques. We observed a linear association between NEAT1 lncRNA expression and prevalence of CAD which was independent of age, sex, cardiovascular traditional risk factors and renal function. NEAT1 expression was induced by TNF-α, while silencing of NEAT1 profoundly attenuated the TNF-α-induced vascular endothelial cell pro-inflammatory response as defined by the expression of CXCL8, CCL2, VCAM1 and ICAM1. Overexpression of the RNA editing enzyme adenosine deaminase acting on RNA-1 (ADAR1), but not of its editing-deficient mutant, upregulated NEAT1 levels. Conversely, silencing of ADAR1 suppressed the basal levels and the TNF-α-induced increase of NEAT1. NEAT1 lncRNA expression was strongly associated with ADAR1 in CAD and peripheral arterial vascular disease. RNA editing mapping studies revealed the presence of several inosines in close proximity to AU-rich elements within the AluSx3 + /AluJodouble-stranded RNA complex. Silencing of the stabilizing RNA-binding protein AUF1 reduced NEAT1 levels while silencing of ADAR1 profoundly affected the binding capacity of AUF1 to NEAT1. Together, our findings propose a mechanism by which ADAR1-catalyzed A-to-I RNA editing controls NEAT1 lncRNA stability in ASCVD.

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Objective Adenosine deaminase acting on RNA-1 (ADAR1) enzyme is a type I interferon (IFN)-stimulated gene (ISG) catalyzing the deamination of adenosine-to-inosine, a process called A-to-I RNA editing. A-to-I RNA editing takes place mainly in Alu elements comprising a primate-specific level of post-transcriptional gene regulation. Whether RNA editing is involved in type I IFN responses in systemic sclerosis (SSc) patients remains unknown. Methods ISG expression was quantified in skin biopsies and peripheral blood mononuclear cells derived from SSc patients and healthy subjects. A-to-I RNA editing was examined in the ADAR1-target cathepsin S ( CTSS ) by an RNA editing assay. The effect of ADAR1 on interferon-α/β-induced CTSS expression was assessed in human endothelial cells in vitro . Results Increased expression levels of the RNA editor ADAR1 , and specifically the long ADAR1p150 isoform, and its target CTSS are strongly associated with type I IFN signature in skin biopsies and peripheral blood derived from SSc patients. Notably, IFN-α/β-treated human endothelial cells show 8-10-fold increased ADAR1p150 and 23-35-fold increased CTSS expression, while silencing of ADAR1 reduces CTSS expression by 60-70%. In SSc patients, increased RNA editing rate of individual adenosines located in CTSS 3 ′ UTR Alu elements is associated with higher CTSS expression (r = 0.36–0.6, P < 0.05 for all). Similar findings were obtained in subjects with activated type I IFN responses including SLE patients or healthy subjects after influenza vaccination. Conclusion ADAR1p150-mediated A-to-I RNA editing is critically involved in type I IFN responses highlighting the importance of post-transcriptional regulation of proinflammatory gene expression in systemic autoimmunity, including SSc.

The COVID-19 pandemic has been a huge challenge for the Greek National Health System. Real-time reverse transcription PCR (rtRT-PCR) remains the reference method for early diagnosis, contact tracing, and containment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The aim of this study is the documentation of the epidemiological features of SARS-CoV-2 laboratory surveillance with rtRT-PCR in the population residing in the Pieria province of Greece. Of the 15,486 nasopharyngeal and oropharyngeal samples tested with real-time reverse transcription PCR for the presence of SARS-CoV-2 RNA, 8,051 (52%) were from females and 7,435 (48%) from males, aged 7 days–103 years, with 69.9% coming from the age group of >40 years. The 4,616 out of 15,486 (29.8%) samples came from hospitalised patients. There were 3,771 positive samples out of 15,486 (24.3%); 1,890 (50.8%) males and 1,881 (49.2%) females, with the age group of 40–59 years being dominant (29.9%). Those diagnosed for the first time made up 3,352 out of 3,771 (88.9%) of positive samples. The monthly positivity rate ranged from 6.24–15.69% during the B.1.1.7 variant wave, 17.38–52.89% during the B.1.617.2 variant wave, and 59.76% during the first month of the B.1.1.529 variant wave. Absence of detection of the spike protein gene target was observed in 1,371 (36.4%) of positive samples. Cycle threshold values <20, indicative of higher viral load, had 43.2% of positive samples during the B.1.1.7, 70.0% during the B.1.617, and 92.0% during the first month of the B.1.1.529 wave. The positivity and distribution of variants in the study population was in accordance with the respective results announced by official government authorities for the Pieria region.