RATIONALE:Circular RNAs (circRNAs) are noncoding RNAs generated by back splicing. Back splicing has been considered a rare event, but recent studies suggest that circRNAs are widely expressed. ...However, the expression, regulation, and function of circRNAs in vascular cells is still unknown.
OBJECTIVE:Here, we characterize the expression, regulation, and function of circRNAs in endothelial cells.
METHODS AND RESULTS:Endothelial circRNAs were identified by computational analysis of ribo-minus RNA generated from human umbilical venous endothelial cells cultured under normoxic or hypoxic conditions. Selected circRNAs were biochemically characterized, and we found that the majority of them lacks polyadenylation, is resistant to RNase R digestion and localized to the cytoplasm. We further validated the hypoxia-induced circRNAs cZNF292, cAFF1, and cDENND4C, as well as the downregulated cTHSD1 by reverse transcription polymerase chain reaction in cultured endothelial cells. Cloning of cZNF292 validated the predicted back splicing of exon 4 to a new alternative exon 1A. Silencing of cZNF292 inhibited cZNF292 expression and reduced tube formation and spheroid sprouting of endothelial cells in vitro. The expression of pre-mRNA or mRNA of the host gene was not affected by silencing of cZNF292. No validated microRNA-binding sites for cZNF292 were detected in Argonaute high-throughput sequencing of RNA isolated by cross-linking and immunoprecipitation data sets, suggesting that cZNF292 does not act as a microRNA sponge.
CONCLUSIONS:We show that the majority of the selected endothelial circRNAs fulfill all criteria of bona fide circRNAs. The circRNA cZNF292 exhibits proangiogenic activities in vitro. These data suggest that endothelial circRNAs are regulated by hypoxia and have biological functions.
Since our knowledge on structure and function of messenger RNA (mRNA) has expanded from merely being an intermediate molecule between DNA and proteins to the notion that RNA is a dynamic gene ...regulator that can be modified and edited, RNA has become a focus of interest into developing novel therapeutic schemes. Therapeutic modulation of RNA molecules by DNA- and RNA-based therapies has broadened the scope of therapeutic targets in infectious diseases, cancer, neurodegenerative diseases and most recently in cardiovascular diseases as well. Currently, antisense oligonucleotides (ASO), small interfering RNAs (siRNAs), and microRNAs are the most widely applied therapeutic strategies to target RNA molecules and regulate gene expression and protein production. However, a number of barriers have to be overcome including instability, inadequate binding affinity and delivery to the tissues, immunogenicity, and off-target toxicity in order for these agents to evolve into efficient drugs. As cardiovascular diseases remain the leading cause of mortality worldwide, a large number of clinical trials are under development investigating the safety and efficacy of RNA therapeutics in clinical conditions such as familial hypercholesterolemia, diabetes mellitus, hypertriglyceridemia, cardiac amyloidosis, and atrial fibrillation. In this review, we summarize the clinical trials of RNA-targeting therapies in cardiovascular disease and critically discuss the advances, the outcomes, the limitations and the future directions of RNA therapeutics in precision transcriptomic medicine.
Sepsis is a life-threatening clinical syndrome characterized by multiorgan dysfunction caused by a dysregulated or over-reactive host response to infection. During sepsis, the coagulation cascade is ...triggered by activated cells of the innate immune system, such as neutrophils and monocytes, resulting in clot formation mainly in the microcirculation, a process known as immunothrombosis. Although this process aims to protect the host through inhibition of the pathogen's dissemination and survival, endothelial dysfunction and microthrombotic complications can rapidly lead to multiple organ dysfunction. The development of treatments targeting endothelial innate immune responses and immunothrombosis could be of great significance for reducing morbidity and mortality in patients with sepsis. Medications modifying cell-specific immune responses or inhibiting platelet-endothelial interaction or platelet activation have been proposed. Herein, we discuss the underlying mechanisms of organ-specific endothelial dysfunction and immunothrombosis in sepsis and its complications, while highlighting the recent advances in the development of new therapeutic approaches aiming at improving the short- or long-term prognosis in sepsis.
Alzheimer's disease (AD) is the leading cause of dementia in the elderly. Growth factors have been demonstrated to act in a synergistic way in angiogenesis and neurogenesis contributing to ...self-healing powers of the adult human brain. A growing body of evidence demonstrates that levels of many growth factors (neurotrophins and hematopoietins) are altered in cerebrospinal fluid and peripheral blood from AD patients and in animal models of AD. The present review summarizes the role of several neurotrophic growth factors (e.g., BDNF, SCF, NGF, GDNF) and haematopoietic growth factors (e.g., G-CSF, VEGF, SDF-1) in AD. Moreover, we summarize recent studies evaluating the diagnostic and prognostic value of growth factor levels in blood and cerebrospinal fluid in patients with AD and discuss the potential role of these growth factors as a promising new therapeutic approach in AD.
Abstract
Aims
The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and its shedding product soluble LOX-1 (sLOX-1) are implicated in atherosclerotic cardiovascular disease (ASCVD) ...pathogenesis. Herein, we examined the relationship of sLOX-1 with both fatal events and plaque progression in patients with acute coronary syndromes (ACS).
Methods and results
Plasma sLOX-1 was assessed at baseline in ACS and chronic coronary syndrome (CCS) patients prospectively recruited in the multicentre SPUM-ACS study, with sex- and age-matched healthy subjects serving as additional controls (n = 2924). Compared with both CCS and controls, ACS patients showed markedly elevated sLOX-1 levels (median, 2.00 and 2.00 vs. 35.08 pg/mL; P < 0.0001) which were independently associated with increased mortality risk over 30-day tertile (T)3: adjusted hazard ratio (HR), 3.11; 95% confidence interval (CI), 1.44–10.61; P = 0.0055 and 1-year intervals (T3: adjusted HR, 2.04; 95% CI, 1.19–3.92; P = 0.0098). Results remained consistent after adjustment for GRACE 2.0 (T3: adjusted HR, 1.86; 95% CI, 1.04–3.74; P = 0.0391) and were primarily driven by the pronounced relationship of sLOX-1 with cardiovascular mortality at 30 days (T3: adjusted HR, 3.81; 95% CI, 1.62–19.62; P = 0.0036) and at 1 year (T3: adjusted HR, 2.29; 95% CI, 1.19–5.34; P = 0.0148). In ACS patients undergoing serial intracoronary imaging and statin therapy, sLOX-1 dropped significantly in those with coronary plaque regression at 1 year (ΔsLOX-1: −4.64 ± 1.80; P = 0.0057), and showed a good discrimination for predicting plaque progression (area under the curve = 0.74; 95% CI, 0.59–0.86; P = 0.0031).
Conclusion
Plasma sLOX-1 levels are increased during ACS and predict fatal events beyond traditional and emerging risk factors. Persistently high sLOX-1 associates with coronary plaque progression in patients with established ASCVD.
Clinical Trial Registration
NCT01000701.
Structured Graphical Abstract
Structured Graphical Abstract
Atherosclerotic plaques express high levels of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), with plaque regions particularly prone for instability showing accentuated LOX-1 abundance. The pro-inflammatory milieu within atherosclerotic plaques enhances LOX-1 synthesis, promotes LOX-1 shedding and thus soluble LOX-1 (sLOX-1) release. The turnover of membrane-bound LOX-1 determines plaque composition and thus stability, with systemically circulating sLOX-1 emerging as a novel biomarker reflecting plaque burden and vulnerability. In this multicentre prospective cohort study, we found that plasma levels of sLOX-1 are markedly elevated in patients presenting with acute coronary syndromes (ACS) when compared with both chronic coronary syndrome (CCS) and healthy subjects (CTRL). High sLOX-1 levels were independently associated with a higher multivariable-adjusted 1-year mortality risk following ACS, a finding that remained consistent after controlling for GRACE 2.0. In patients subjected to serial intravascular ultrasound following the index ACS, sLOX-1 dropped markedly in those with coronary plaque regression, while persistently high sLOX-1 levels were associated with plaque progression. §Adjusted for sex, age, ACS type, hs-CRP, history of hypercholesterolaemia, eGFR, LDL-C, and diagnosis of diabetes; †adjusted for sex, age, ACS type, hs-CRP, history of hypercholesterolaemia, eGFR, LDL-C, diagnosis of diabetes, NT-proBNP, and hs-TnT. ADAM, a disintegrin and metalloproteinase; GRACE, Global Registry of Acute Coronary Events; IVUS, intravascular ultrasound; MMP, matrix metalloproteinase; LOX-1, lectin-like oxidized low-density lipoprotein receptor-1; sLOX-1, soluble LOX-1.
Adenosine-to-inosine (A-to-I) RNA editing of Alu retroelements is a primate-specific mechanism mediated by adenosine deaminases acting on RNA (ADARs) that diversifies transcriptome by changing ...selected nucleotides in RNA molecules. We tested the hypothesis that A-to-I RNA editing is altered in rheumatoid arthritis (RA).
Synovium expression analysis of ADAR1 was investigated in 152 RA patients and 50 controls. Peripheral blood mononuclear cells derived from 14 healthy subjects and 19 patients with active RA at baseline and after 12-week treatment were examined for ADAR1p150 and ADAR1p110 isoform expression by RT-qPCR. RNA editing activity was analysed by AluSx+ Sanger-sequencing of cathepsin S, an extracellular matrix degradation enzyme involved in antigen presentation.
ADAR1 was significantly over-expressed in RA synovium regardless of disease duration. Similarly, ADAR1p150 isoform expression was significantly increased in the blood of active RA patients. Individual nucleotide analysis revealed that A-to-I RNA editing rate was also significantly increased in RA patients. Both baseline ADAR1p150 expression and individual adenosine RNA editing rate of cathepsin S AluSx+ decreased after treatment only in those patients with good clinical response. Upregulation of the expression and/or activity of the RNA editing machinery were associated with a higher expression of edited Alu-enriched genes including cathepsin S and TNF receptor-associated factors 1,2,3 and 5.
A previously unrecognized regulation and role of ADAR1p150-mediated A-to-I RNA editing in post-transcriptional control in RA underpins therapeutic response and fuels inflammatory gene expression, thus representing an interesting therapeutic target.
•The RNA editing enzyme ADAR1 is increased in rheumatoid arthritis.•ADAR1-induced Alu A-to-I RNA editing is increased in active RA and decreases after treatment only in responding patients.•Association of increased A-to-I RNA editing with pro-inflammatory gene expression suggests a role in chronic inflammation.•Interrupting the pro-inflammatory ADAR1p150-induced Alu RNA editing may comprise an interesting therapeutic target in RA.
Abstract Circulating amyloid-beta 1–40 (Αb40) has pro-atherogenic properties and could serve as a biomarker in atherosclerotic cardiovascular disease (ASCVD). However, the association of Ab40 levels ...with morphological characteristics reflecting atherosclerotic plaque echolucency and composition is not available. Carotid atherosclerosis was assessed in consecutively recruited individuals without ASCVD ( n = 342) by ultrasonography. The primary endpoint was grey scale median (GSM) of intima-media complex (IMC) and plaques, analysed using dedicated software. Vascular markers were assessed at two time-points (median follow-up 35.5 months). In n = 56 patients undergoing carotid endarterectomy, histological plaque features were analysed. Plasma Αb40 levels were measured at baseline. Ab40 was associated with lower IMC GSM and plaque GSM and higher plaque area at baseline after multivariable adjustment. Increased Ab40 levels were also longitudinally associated with decreasing or persistently low IMC and plaque GSM after multivariable adjustment ( p < 0.05). In the histological analysis, Ab40 levels were associated with lower incidence of calcified plaques and plaques without high-risk features. Ab40 levels are associated with ultrasonographic and histological markers of carotid wall composition both in the non-stenotic arterial wall and in severely stenotic plaques. These findings support experimental evidence linking Ab40 with plaque vulnerability, possibly mediating its established association with major adverse cardiovascular events.
Atherosclerosis is a chronic inflammatory disease. Lesion progression is primarily mediated by cells of the monocyte/macrophage lineage. IL-17A is a proinflammatory cytokine, which modulates immune ...cell trafficking and is involved inflammation in (auto)immune and infectious diseases. But the role of IL-17A still remains controversial. In the current study, we investigated effects of IL-17A on advanced murine and human atherosclerosis, the common disease phenotype in clinical care. The 26-wk-old apolipoprotein E-deficient mice were fed a standard chow diet and treated either with IL-17A mAb (n = 15) or irrelevant Ig (n = 10) for 16 wk. Furthermore, essential mechanisms of IL-17A in atherogenesis were studied in vitro. Inhibition of IL-17A markedly prevented atherosclerotic lesion progression (p = 0.001) by reducing inflammatory burden and cellular infiltration (p = 0.01) and improved lesion stability (p = 0.01). In vitro experiments showed that IL-17A plays a role in chemoattractance, monocyte adhesion, and sensitization of APCs toward pathogen-derived TLR4 ligands. Also, IL-17A induced a unique transcriptome pattern in monocyte-derived macrophages distinct from known macrophage types. Stimulation of human carotid plaque tissue ex vivo with IL-17A induced a proinflammatory milieu and upregulation of molecules expressed by the IL-17A-induced macrophage subtype. In this study, we show that functional blockade of IL-17A prevents atherosclerotic lesion progression and induces plaque stabilization in advanced lesions in apolipoprotein E-deficient mice. The underlying mechanisms involve reduced inflammation and distinct effects of IL-17A on monocyte/macrophage lineage. In addition, translational experiments underline the relevance for the human system.
Carfilzomib (CFZ) improves survival in relapsed/refractory multiple myeloma but is associated with cardiovascular adverse events (CVAEs). We prospectively investigated the effect of CFZ on ...endothelial function and associations with CVAEs. Forty-eight patients treated with Kd (CFZ 20/56 mg/m
and dexamethasone) underwent serial endothelial function evaluation, using brachial artery flow-mediated dilatation (FMD) and 26S proteasome activity (PrA) measurement in PBMCs; patients were followed until disease progression or cycle 6 for a median of 10 months. FMD and PrA decreased acutely after the first dose (p < 0.01) and FMD decreased at cycles 3 and 6 compared to baseline (p ≤ 0.05). FMD changes were associated with CFZ-induced PrA changes (p < 0.05) and lower PrA recovery during first cycle was associated with more prominent FMD decrease (p = 0.034 for group interaction). During treatment, 25 patients developed Grade ≥3 CVAEs. Low baseline FMD (HR 2.57 lowest vs. higher tertiles, 95% CI 1.081-6.1) was an independent predictor of CVAEs. During treatment, an acute FMD decrease >40% at the end of first cycle was also independently associated with CVAEs (HR = 3.91, 95% CI 1.29-11.83). Kd treatment impairs endothelial function which is associated with PrA inhibition and recovery. Both pre- and posttreatment FMD predicted CFZ-related CVAEs supporting its role as a possible cardiovascular toxicity biomarker.
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