RNA Therapeutics in Cardiovascular Precision Medicine

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

Cathepsin S Levels and Survival Among Patients With Non-ST-Segment Elevation Acute Coronary Syndromes

Patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS) are at high residual risk for long-term cardiovascular (CV) mortality. Cathepsin S (CTSS) is a lysosomal cysteine protease with elastolytic and collagenolytic activity that has been involved in atherosclerotic plaque rupture.; The purpose of this study was to determine the following: 1) the prognostic value of circulating CTSS measured at patient admission for long-term mortality in NSTE-ACS; and 2) its additive value over the GRACE (Global Registry of Acute Coronary Events) risk score.; This was a single-center cohort study, consecutively recruiting patients with adjudicated NSTE-ACS (n = 1,112) from the emergency department of an academic hospital. CTSS was measured in serum using enzyme-linked immunosorbent assay. All-cause mortality at 8 years was the primary endpoint. CV death was the secondary endpoint.; In total, 367 (33.0%) deaths were recorded. CTSS was associated with increased risk of all-cause mortality (HR for highest vs lowest quarter of CTSS: 1.89; 95% CI: 1.34-2.66; P < 0.001) and CV death (HR: 2.58; 95% CI: 1.15-5.77; P = 0.021) after adjusting for traditional CV risk factors, high-sensitivity C-reactive protein, left ventricular ejection fraction, high-sensitivity troponin-T, revascularization and index diagnosis (unstable angina/ non-ST-segment elevation myocardial infarction). When CTSS was added to the GRACE score, it conferred significant discrimination and reclassification value for all-cause mortality (Delta Harrell's C: 0.03; 95% CI: 0.012-0.047; P = 0.001; and net reclassification improvement = 0.202; P = 0.003) and CV death (AUC: 0.056; 95% CI: 0.017-0.095; P = 0.005; and net reclassification improvement = 0.390; P = 0.001) even after additionally considering high-sensitivity troponin-T and left ventricular ejection fraction.; Circulating CTSS is a predictor of long-term mortality and improves risk stratification of patients with NSTE-ACS over the GRACE score

Dawn of Epitranscriptomic Medicine

Medicine is at the crossroads of expanding disciplines. Prompt adaptation of medicine to each rapidly advancing research field, bridging bench to bedside, is a key step toward health improvement. Cardiovascular disease still ranks first among the mortality causes in the Western world, indicating a poor adaptation rate of cardiovascular medicine, albeit the gigantic scientific breakthroughs of this century. This urges the cardiovascular research field to explore novel concepts with promising prognostic and therapeutic potential. This review attempts to introduce the newly emerging field of epitranscriptome (or else known as RNA epigenetics) to cardiovascular researchers and clinicians summarizing its applications on health and disease. The traditionally perceived, intermediate carrier of genetic information or as contemporary revised as, occasionally, even the final product of gene expression, RNA, is dynamically subjected to >140 different kinds of chemical modifications determining its fate, which may profoundly impact the cellular responses and thus both health and disease course. Which are the most prevalent types of these RNA modifications, how are they catalyzed, how are they regulated, which role may they play in health and disease, and which are the implications for the cardiovascular medicine are few important questions that are discussed in the present review

Reactive Vasodilation Predicts Mortality in Primary Systemic Light-Chain Amyloidosis

Rationale: Cardiac involvement and hypotension dominate the prognosis of light-chain amyloidosis (AL). Evidence suggests that there is also peripheral vascular involvement in AL but its prognostic significance is unknown. Objective: To evaluate vascular dysfunction in patients with AL as a potential future area of intervention, we assessed the prognostic utility of flow-mediated dilatation (FMD), a marker of vascular reactivity, which is augmented under conditions of hypotension and autonomic dysfunction. Methods and Results: We prospectively evaluated 115 newly diagnosed untreated AL patients in whom FMD was measured. FMD in AL patients was significantly higher than age-, sex- and risk factors–matched controls (4.0% versus 2.32%; P=0.006) and comparable with control groups at lower cardiovascular risk (P>0.1). Amyloidosis patients presented increased plasma and exhaled markers of the NO pathway while their FMD significantly correlated with augmented sustained vasodilatation after sympathetic stimulation. Increased FMD (≥4.5%) was associated with early mortality (hazard ratio, 4.36; 95% CI, 1.41–13.5; P=0.010) and worse survival (hazard ratio, 2.11; 95% CI, 1.17–3.82; P=0.013), even after adjustment for Mayo stage, nerve involvement and low systolic blood pressure. This finding was confirmed in a temporal validation AL cohort (n=55; hazard ratio, 4.2; 95% CI, 1.45–12.3; P=0.008). FMD provided significant reclassification value over the best prognostic model (continuous Net Reclassification Index, 0.61; P=0.001). Finally, better hematologic response was associated with lower posttreatment FMD. Conclusions: FMD is relatively increased in AL and independently associated with inferior survival with substantial reclassification value. Reactive vasodilation merits further investigation as a novel risk biomarker in AL.Visual Overview: An online visual overview is available for this article

Increased adenosine-to-inosine RNA editing in rheumatoid arthritis

Objective 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). Methods 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. Results 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. Conclusion 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

Interleukin-17A Triggers the Release of Platelet-Derived Factors Driving Vascular Endothelial Cells toward a Pro-Angiogenic State

Platelets comprise a highly interactive immune cell subset of the circulatory system traditionally known for their unique haemostatic properties. Although platelets are considered as a vault of growth factors, cytokines and chemokines with pivotal role in vascular regeneration and angiogenesis, the exact mechanisms by which they influence vascular endothelial cells (ECs) function remain underappreciated. In the present study, we examined the role of human IL-17A/IL-17RA axis in platelet-mediated pro-angiogenic responses. We reveal that IL-17A receptor (IL-17RA) mRNA is present in platelets transcriptome and a profound increase is documented on the surface of activated platelets. By quantifying the protein levels of several factors, involved in angiogenesis, we identified that IL-17A/IL17RA axis selectively induces the release of vascular endothelial growth factor, interleukin -2 and -4, as well as monocyte chemoattractant protein -1 from treated platelets. However, IL-17A exerted no effect on the release of IL-10, an anti-inflammatory factor with potentially anti-angiogenic properties, from platelets. Treatment of human endothelial cell two-dimensional tubule networks or three-dimensional spheroid and mouse aortic ring structures with IL-17A-induced platelet releasate evoked pro-angiogenic responses of ECs. Our findings suggest that IL-17A may critically affect platelet release of pro-angiogenic factors driving ECs towards a pro-angiogenic state

RNA Therapeutics in Cardiovascular Precision Medicine

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

MicroRNAs in platelet biogenesis and function : implications in vascular homeostasis and inflammation

Platelets are involved in vascular homeostasis and inflammation through interaction with circulating blood cells and vascular wall. MiRNAs are small, conserved and non-coding RNA molecules, which interact directly with specific mRNAs regions regulating gene expression. The purpose of this review is to gather all known platelet miRNAs and summarize their role in platelet biogenesis and function. Increasing evidence supports the role of miR-34a and miR-150 in megakaryocytopoiesis and platelet production. Although 284 miRNAs are described to be present in platelets, their role is mostly unknown. The most abundant miRNA in platelets is miR-223 followed by miR-126. The miR-96, miR-200b, miR- 495, miR-107 and miR-223 are critically involved in platelet reactivity, aggregation, secretion and adhesion. The presence of miRNAs known to regulate angiogenesis in platelets is also discussed. Furthermore, platelet-derived microvesicles and microparticles contain several miRNAs, which may facilitate the communication between platelets with other vascular cells, a mechanism that may play an important role in vascular homeostasis and inflammation. Further studies are needed to elucidate the exact roles of platelet miRNAs in platelet function and vascular biology

Interleukin-17A triggers the release of platelet-derived factors driving vascular endothelial cells toward a pro-angiogenic state

Platelets comprise a highly interactive immune cell subset of the circulatory system traditionally known for their unique haemostatic properties. Although platelets are considered as a vault of growth factors, cytokines and chemokines with pivotal role in vascular regeneration and angiogenesis, the exact mechanisms by which they influence vascular endothelial cells (ECs) function remain underappreciated. In the present study, we examined the role of human IL-17A/IL-17RA axis in platelet-mediated pro-angiogenic responses. We reveal that IL-17A receptor (IL-17RA) mRNA is present in platelets transcriptome and a profound increase is documented on the surface of activated platelets. By quantifying the protein levels of several factors, involved in angiogenesis, we identified that IL-17A/IL17RA axis selectively induces the release of vascular endothelial growth factor, interleukin -2 and -4, as well as monocyte chemoattractant protein -1 from treated platelets. However, IL-17A exerted no effect on the release of IL-10, an anti-inflammatory factor with potentially anti-angiogenic properties, from platelets. Treatment of human endothelial cell two-dimensional tubule networks or three-dimensional spheroid and mouse aortic ring structures with IL-17A-induced platelet releasate evoked pro-angiogenic responses of ECs. Our findings suggest that IL-17A may critically affect platelet release of pro-angiogenic factors driving ECs towards a pro-angiogenic state