Association of MicroRNAs and YRNAs With Platelet Function

Fragments derived from non-coding RNAs: how complex is genome regulation?

The human genome is highly dynamic and only a small fraction of it codes for proteins, but most of the genome is transcribed, highlighting the importance of non-coding RNAs on cellular functions. In addition, it is now known the generation of non-coding RNA fragments under particular cellular conditions and their functions have revealed unexpected mechanisms of action, converging, in some cases, with the biogenic pathways and action machineries of microRNAs or Piwi-interacting RNAs. This led us to the question why the cell produces so many apparently redundant molecules to exert similar functions and regulate apparently convergent processes? However, non-coding RNAs fragments can also function similarly to aptamers, with secondary and tertiary conformations determining their functions. In the present work, it was reviewed and analyzed the current information about the non-coding RNAs fragments, describing their structure and biogenic pathways, with special emphasis on their cellular functions.

Influence of Genetic and Epigenetic Factors of P2Y12 Receptor on the Safety and Efficacy of Antiplatelet Drugs

PURPOSE

P2Y12 receptor inhibitors are drugs that decrease the risk of stent thrombosis and lower the long-term risk of non-stent-related myocardial infarction and stroke. They inhibit the binding of adenosine diphosphate (ADP) to the P2Y12 receptor and effectively reduce platelet reactivity. However, considerable variability in the pharmacodynamics response contributes to a failure of antiplatelet therapy; this phenomenon is especially notorious for older drugs, such as clopidogrel. Some genetic polymorphisms associated with these drugs' metabolic pathway, especially in the CYP2C19 gene, can significantly decrease antiplatelet efficacy. There are few reports on the variability stemming from the target of this drug class that is the P2Y12 receptor itself.

RESULTS AND CONCLUSION

This review summarizes the results of research that focus on the influence of P2Y12 genetic polymorphisms on the pharmacodynamics and the efficacy of P2Y12 inhibitors. We found that the conclusions of the studies are unequivocal, and despite several strong candidates, such as G52T (rs6809699) or T744C (rs2046934), they may not be independent predictors of the inadequate response to the drug. Most probably, P2Y12 genetic polymorphisms contribute to the effect exerted by other gene variants (such as CYP2C19*2/*3/*17), drug interactions, or patient habits, such as smoking. Also, epigenetic modifications, such as methylation or miRNA levels, may play a role in the efficacy of antiplatelet treatment.

Effect of Alirocumab Added to High-Intensity Statin on Platelet Reactivity and Noncoding RNAs in Patients with AMI: A Substudy of the PACMAN-AMI Trial

OBJECTIVE

 The effect of the PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor alirocumab on platelet aggregation among patients with acute myocardial infarction (AMI) remains unknown. We aimed to explore the effect of alirocumab added to high-intensity statin therapy on P2Y12 reaction unit (PRU) among AMI patients receiving dual antiplatelet therapy (DAPT) with a potent P2Y12 inhibitor (ticagrelor or prasugrel). In addition, we assessed circulating platelet-derived noncoding RNAs (microRNAs and YRNAs).

METHODS

 This was a prespecified, powered, pharmacodynamic substudy of the PACMAN trial, a randomized, double-blind trial comparing biweekly alirocumab (150 mg) versus placebo in AMI patients undergoing percutaneous coronary intervention. Patients recruited at Bern University Hospital, receiving DAPT with a potent P2Y12 inhibitor, and adherent to the study drug (alirocumab or placebo) were analyzed for the current study. The primary endpoint was PRU at 4 weeks after study drug initiation as assessed by VerifyNow P2Y12 point-of-care assays.

RESULTS

 Among 139 randomized patients, the majority of patients received ticagrelor DAPT at 4 weeks (57 [86.4%] in the alirocumab group vs. 69 [94.5%] in the placebo group, p = 0.14). There were no significant differences in the primary endpoint PRU at 4 weeks between groups (12.5 [interquartile range, IQR: 27.0] vs. 19.0 [IQR: 30.0], p = 0.26). Consistent results were observed in 126 patients treated with ticagrelor (13.0 [IQR: 20.0] vs. 18.0 [IQR: 27.0], p = 0.28). Similarly, platelet-derived noncoding RNAs did not significantly differ between groups.

CONCLUSION

 Among AMI patients receiving DAPT with a potent P2Y12 inhibitor, alirocumab had no significant effect on platelet reactivity as assessed by PRU and platelet-derived noncoding RNAs.

microRNAs and thrombo-inflammation: relationship in sight

PURPOSE OF REVIEW

Thrombo-inflammation is a multifaceted pathologic process involving various cells such as platelets, neutrophils, and monocytes. In recent years, microRNAs have been consistently implicated as regulators of these cells.

RECENT FINDINGS

MicroRNAs play a regulatory role in several platelet receptors that have recently been identified as contributing to thrombo-inflammation and neutrophil extracellular trap (NET) formation. In addition, a growing body of evidence has shown that several intracellular and extracellular microRNAs directly promote NET formation.

SUMMARY

Targeting microRNAs is a promising therapeutic approach to control thrombosis in patients with both infectious and noninfectious inflammatory diseases. Future research efforts should focus on elucidating the specific roles of microRNAs in thrombo-inflammation and translating these findings into tangible benefits for patients.

Platelet Function and Maturity and Related microRNA Expression in Whole Blood in Patients with ST-Segment Elevation Myocardial Infarction

BACKGROUND

 Reduced effect of antiplatelet therapy has been reported in patients with ST-segment elevation myocardial infarction (STEMI). MicroRNAs (miRs) may influence platelet function and maturity, and subsequently the effect of antiplatelet therapy.

OBJECTIVES

 We aimed to explore the association between miR expression and platelet function and maturity in patients with acute STEMI and healthy individuals.

METHODS

 We performed an observational study of STEMI patients admitted directly to primary percutaneous coronary intervention. Patients were treated with antiplatelet therapy according to guidelines. Within 24 hours after admission, blood samples were obtained to measure: the expression of 10 candidate miRs, platelet function markers using advanced flow cytometry, platelet aggregation, serum thromboxane B2, and platelet maturity markers. Furthermore, blood samples from healthy individuals were obtained to determine the normal variation.

RESULTS

 In total, 61 STEMI patients and 50 healthy individuals were included. STEMI patients had higher expression of miR-21-5p, miR-26b-5p, and miR-223-3p and lower expression of miR-150-5p, miR423-5p, and miR-1180-3p than healthy individuals. In STEMI patients, the expression of miR-26b-5p showed the most consistent association with platelet function (all p-values <0.05, Spearman's rho ranging from 0.27 to 0.41), while the expression of miR-150-5p and miR-223-3p showed negative associations with platelet function. No association between miR expression and platelet maturity markers was observed.

CONCLUSION

 In patients with STEMI, the expression of six miRs was significantly different from healthy individuals. The expression of miR-26b-5p may affect platelet function in acute STEMI patients and potentially influence the effect of antiplatelet therapy.

MicroRNAs and Cardiovascular Disease Risk

PURPOSE OF REVIEW

MicroRNAs (miRNAs)-short, non-coding RNAs-play important roles in almost all aspects of cardiovascular biology, and changes in intracellular miRNA expression are indicative of cardiovascular disease development and progression. Extracellular miRNAs, which are easily measured in blood and can be reflective of changes in intracellular miRNA levels, have emerged as potential non-invasive biomarkers for disease. This review summarizes current knowledge regarding miRNAs as biomarkers for assessing cardiovascular disease risk and prognosis.

RECENT FINDINGS

Numerous studies over the last 10-15 years have identified associations between extracellular miRNA profiles and cardiovascular disease, supporting the potential use of extracellular miRNAs as biomarkers for risk stratification. However, clinical application of extracellular miRNA profiles has been hampered by poor reproducibility and inter-study variability that is due largely to methodological differences between studies. While recent studies indicate that circulating extracellular miRNAs are promising biomarkers for cardiovascular disease, evidence for clinical implementation is lacking. This highlights the need for larger, well-designed studies that use standardized methods for sample preparation, miRNA isolation, quantification, and normalization.

Prothymosin α accelerates dengue virus-induced thrombocytopenia

Thrombocytopenia is the hallmark finding in dengue virus (DENV) infection. Prothymosin α (ProT) has both intracellular and extracellular functions involved in cell cycle progression, cell differentiation, gene regulation, oxidative stress response, and immunomodulation. In this study, we found that ProT levels were elevated in dengue patient sera as well as DENV-infected megakaryoblasts and their culture supernatants. ProT transgenic mice had reduced platelet counts with prolonged bleeding times. Upon treatment with DENV plus anti-CD41 antibody, they exhibited severe skin hemorrhage. Furthermore, overexpression of ProT suppressed megakaryocyte differentiation. Infection with DENV inhibited miR-126 expression, upregulated DNA (cytosine-5)-methyltransferase 1 (DNMT1), downregulated GATA-1, and increased ProT expression. Upregulation of ProT led to Nrf2 activation and reduced reactive oxygen species production, thereby suppressing megakaryopoiesis. We report the pathophysiological role of ProT in DENV infection and propose an involvement of the miR-126-DNMT1-GATA-1-ProT-Nrf2 signaling axis in DENV-induced thrombocytopenia.

RNA interference-based therapies for atherosclerosis: Recent advances and future prospects

Atherosclerosis represents a pathological state that affects the arterial system of the organism. This chronic, progressive condition is typified by the accumulation of atheroma within arterial walls. Modulation of RNA molecules through RNA-based therapies has expanded the range of therapeutic options available for neurodegenerative diseases, infectious diseases, cancer, and, more recently, cardiovascular disease (CVD). Presently, microRNAs and small interfering RNAs (siRNAs) are the most widely employed therapeutic strategies for targeting RNA molecules, and for regulating gene expression and protein production. Nevertheless, for these agents to be developed into effective medications, various obstacles must be overcome, including inadequate binding affinity, instability, challenges of delivering to the tissues, immunogenicity, and off-target toxicity. In this comprehensive review, we discuss in detail the current state of RNA interference (RNAi)-based therapies.

Platelet protein synthesis, regulation, and post-translational modifications: mechanics and function

Dogma had been firmly entrenched in the minds of the scientific community that the anucleate mammalian platelet was incapable of protein biosynthesis since their identification in the late 1880s. These beliefs were not challenged until the 1960s when several reports demonstrated that platelets possessed the capacity to biosynthesize proteins. Even then, many still dismissed the synthesis as trivial and unimportant for at least another two decades. Research in the field expanded after the 1980s and numerous reports have since been published that now clearly demonstrate the potential significance of platelet protein synthesis under normal, pathological, and activating conditions. It is now clear that the platelet proteome is not a static entity but can be altered slowly or rapidly in response to external signals to support physiological requirements to maintain hemostasis and other biological processes. All the necessary biological components to support protein synthesis have been identified in platelets along with post-transcriptional processing of mRNAs, regulators of translation, and post-translational modifications such as glycosylation. The last comprehensive review of the subject appeared in 2009 and much work has been conducted since that time. The current review of the field will briefly incorporate the information covered in earlier reviews and then bring the reader up to date with more recent findings.

Circulating endothelial extracellular vesicle signatures correspond with ICU requirement: an exploratory study in COVID-19 patients

Extracellular vesicles (EVs) represent nanometer-sized, subcellular spheres, that are released from almost any cell type and carry a wide variety of biologically relevant cargo. In severe cases of coronavirus disease 2019 (COVID-19) and other states of systemic pro-inflammatory activation, EVs, and their cargo can serve as conveyors and indicators for disease severity and progression. This information may help distinguish individuals with a less severe manifestation of the disease from patients who exhibit severe acute respiratory distress syndrome (ARDS) and require intensive care measures. Here, we investigated the potential of EVs and associated miRNAs to distinguish normal ward patients from intensive care unit (ICU) patients (N = 10/group), with 10 healthy donors serving as the control group. Blood samples from which plasma and subsequently EVs were harvested by differential ultracentrifugation (UC) were obtained at several points in time throughout treatment. EV-enriched fractions were characterized by flow cytometry (FC), nanoparticle tracking analysis (NTA), and qPCR to determine the presence of selected miRNAs. Circulating EVs showed specific protein signatures associated with endothelial and platelet origin over the course of the treatment. Additionally, significantly higher overall EV quantities corresponded with increased COVID-19 severity. MiR-223-3p, miR-191-5p, and miR-126-3p exhibited higher relative expression in the ICU group. Furthermore, EVs presenting endothelial-like protein signatures and the associated miR-126-3p showed the highest area under the curve in terms of receiver operating characteristics regarding the requirement for ICU treatment. In this exploratory investigation, we report that specific circulating EVs and miRNAs appear at higher levels in COVID-19 patients, especially when critical care measures are indicated. Our data suggest that endothelial-like EVs and associated miRNAs likely represent targets for future laboratory assays and may aid in clinical decision-making in COVID-19.

Characterization of all small RNAs in and comparisons across cultured megakaryocytes and platelets of healthy individuals and COVID-19 patients

BACKGROUND

The small noncoding RNAs (sncRNAs) in megakaryocytes (MKs) and platelets are not well characterized. Neither is the impact of SARS-CoV-2 infection on the sncRNAs of platelets.

OBJECTIVES

To investigate the sorting of MK sncRNAs into platelets, and the differences in the platelet sncRNAomes of healthy donors (HDs) and COVID-19 patients.

METHODS

We comprehensively profiled sncRNAs from MKs cultured from cord blood-derived CD34+ cells, platelets from HDs, and platelets from patients with moderate and severe SARS-CoV-2 infection. We also comprehensively profiled Argonaute (AGO)-bound sncRNAs from the cultured MKs.

RESULTS

We characterized the sncRNAs in MKs and platelets and can account for ∼95% of all sequenced reads. We found that MKs primarily comprise microRNA isoforms (isomiRs), tRNA-derived fragments (tRFs), rRNA-derived fragments (rRFs), and Y RNA-derived fragments (yRFs) in comparable abundances. The platelets of HDs showed a skewed distribution by comparison: 56.7% of all sncRNAs are yRFs, 34.4% are isomiRs, and <2.0% are tRFs and rRFs. Most isomiRs in MKs and platelets are either noncanonical, nontemplated, or both. When comparing MKs and platelets from HDs, we found numerous isomiRs, tRFs, rRFs, and yRFs showing opposite enrichments or depletions, including molecules from the same parental miRNA arm, tRNA, rRNA, or Y RNA. The sncRNAome of platelets from patients with COVID-19 is skewed compared to that of HDs with only 19.8% of all sncRNAs now being yRFs, isomiRs increasing to 63.6%, and tRFs and rRFs more than tripling their presence to 6.1%.

CONCLUSION

The sncRNAomes of MKs and platelets are very rich and more complex than it has been believed. The evidence suggests complex mechanisms that sort MK sncRNAs into platelets. SARS-CoV-2 infection acutely alters the contents of platelets by changing the relative proportions of their sncRNAs.

B, Kappelmayer J, Kőszegi Z, Csanádi Z, Szük T. Technically Challenging Percutaneous Interventions of Chronic Total Occlusions Are Associated with Enhanced Platelet Activation

Percutaneous coronary intervention (PCI) is a frequently performed treatment option for recanalization in patients with chronic total occlusion (CTO). As CTO-PCIs are often complicated and challenging for interventionalists, the stressful and damaging nature of the procedure can be remarkable, thus platelets can be easily activated. Our aim was to investigate the effect of CTO-PCI on platelet activation and the expression of selected circulating microRNAs (miR) of platelet and endothelium origin after CTO-PCI. In this study, 50 subjects after CTO-PCI were enrolled. Blood samples were obtained before PCI, at 2 days and 3-6 months after the procedure to measure the degree of platelet activation and the level of plasma miR-223, miR-181b, and miR-126. Patients were divided based on the characteristics of the intervention. Patients with higher Japanese CTO scores and longer duration of PCI showed significantly elevated platelet P-selectin positivity (p = 0.004 and p = 0.013, respectively) 2 days after the procedure compared to pre-PCI and increased concentration of soluble P-selectin 3-6 months after the intervention (higher Japanese CTO score: p = 0.028 and longer duration of PCI: p = 0.023) compared to baseline values. Shorter total stent length caused a significantly lower miR-181b expression at 3-6 months after the intervention (p = 0.031), while no difference was observed in miR-223 and miR-126. One stent thrombosis occurred during the follow-up period. Although these technically challenging CTO-PCIs may cause enhanced platelet activation right after the intervention and long-term endothelial cell dysfunction, these interventions are not associated with more adverse clinical events.

Platelets and the Atherosclerotic Process: An Overview of New Markers of Platelet Activation and Reactivity, and Their Implications in Primary and Secondary Prevention

The key role played by platelets in the atherosclerosis physiopathology, especially in the acute setting, is ascertained: they are the main actors during thrombus formation and, thus, one of the major investigated elements related to atherothrombotic process involving coronary arteries. Platelets have been studied from different points of view, according with the technology advances and the improvement in the hemostasis knowledge achieved in the last years. Morphology and reactivity constitute the first aspects investigated related to platelets with a significant body of evidence published linking a number of their values and markers to coronary artery disease and cardiovascular events. Recently, the impact of genetics on platelet activation has been explored with promising findings as additional instrument for patient risk stratification; however, this deserves further confirmations. Moreover, the interplay between immune system and platelets has been partially elucidated in the last years, providing intriguing elements that will be basic components for future research to better understand platelet regulation and improve cardiovascular outcome of patients.

The potential role of micro-RNA 125b-5p level in predicting outcome from thrombolytic therapy in patients with acute ischemic stroke

Several studies highlighted a significant role of specific miRNA as diagnostic and prognostic biomarkers for acute ischemic stroke. The aim of this work was to study micro-RNA 125b-5p level in patients with acute ischemic stroke in relation to stroke etiology, risk factors, severity and outcome. This case-control study was conducted on 40 patients with acute ischemic stroke eligible for receiving rt-PA and 40 age and sex matched healthy controls, Patients were submitted to neurological and radiological assessment. Functional outcome after 3 months was assessed using the modified Rankin Scale (mRS). Plasma micro-RNA 125b-5p levels were measured for both patients and control groups by quantitative real time PCR. MiRNA-125b-5p was extracted from the plasma samples then Real-time quantitative reversed transcription PCR (RT-qPCR) analysis was done. To analyze miRNA-125b-5p expression in plasma, the ∆Cq value of miRNA-125b-5p was calculated by subtracting Cq of miRNA-125b-5p from the average Cq of MiRNA RNU6B. Stroke patients had significantly higher circulating micro-RNA 125b-5p levels in comparison to healthy controls (P value = 0.01). The circulating levels of micro-RNA 125b-5p were positively correlated with stroke severity assessed by National Institutes of Health Stroke Scale (NIHSS) and infarction size. Stroke patients with poor outcome had significantly higher circulating levels of micro-RNA 125b-5p in comparison to those with good outcome (P value ≤ 0.001). The circulating levels of micro-RNA 125b-5p were significantly higher in patients who developed complications after receiving rt-PA (P value ≤ 0.001). Logistic regression model revealed that each unit increase in micro-RNA125b-5p decreased the odds of good outcome by 0.095 (95% CI 0.016-0.58, P value = 0.011). Plasma micro-RNA 125b-5p is significantly elevated is ischemic stroke patients. It is positively correlated with stroke severity and strongly associated with poor outcome and complications after thrombolytic therapy.

Inflammatory microRNAs in cardiovascular pathology: another brick in the wall

The regulatory role of microRNAs (miRNAs) is mainly mediated by their effect on protein expression and is recognized in a multitude of pathophysiological processes. In recent decades, accumulating evidence has interest in these factors as modulatory elements of cardiovascular pathophysiology. Furthermore, additional biological processes have been identified as new components of cardiovascular disease etiology. In particular, inflammation is now considered an important cardiovascular risk factor. Thus, in the present review, we will focus on the role of a subset of miRNAs called inflamma-miRs that may regulate inflammatory status in the development of cardiovascular pathology. According to published data, the most representative candidates that play functional roles in thromboinflammation are miR-21, miR-33, miR-34a, miR-146a, miR-155, and miR-223. We will describe the functions of these miRNAs in several cardiovascular pathologies in depth, with specific emphasis on the molecular mechanisms related to atherogenesis. We will also discuss the latest findings on the role of miRNAs as regulators of neutrophil extracellular traps and their impact on cardiovascular diseases. Overall, the data suggest that the use of miRNAs as therapeutic tools or biomarkers may improve the diagnosis or prognosis of adverse cardiovascular events in inflammatory diseases. Thus, targeting or increasing the levels of adequate inflamma-miRs at different stages of disease could help mitigate or avoid the development of cardiovascular morbidities.

The Novel Role of Noncoding RNAs in Modulating Platelet Function: Implications in Activation and Aggregation

It is currently believed that plaque complication, with the consequent superimposed thrombosis, is a key factor in the clinical occurrence of acute coronary syndromes (ACSs). Platelets are major players in this process. Despite the considerable progress made by the new antithrombotic strategies (P2Y12 receptor inhibitors, new oral anticoagulants, thrombin direct inhibitors, etc.) in terms of a reduction in major cardiovascular events, a significant number of patients with previous ACSs treated with these drugs continue to experience events, indicating that the mechanisms of platelet remain largely unknown. In the last decade, our knowledge of platelet pathophysiology has improved. It has been reported that, in response to physiological and pathological stimuli, platelet activation is accompanied by de novo protein synthesis, through a rapid and particularly well-regulated translation of resident mRNAs of megakaryocytic derivation. Although the platelets are anucleate, they indeed contain an important fraction of mRNAs that can be quickly used for protein synthesis following their activation. A better understanding of the pathophysiology of platelet activation and the interaction with the main cellular components of the vascular wall will open up new perspectives in the treatment of the majority of thrombotic disorders, such as ACSs, stroke, and peripheral artery diseases before and after the acute event. In the present review, we will discuss the novel role of noncoding RNAs in modulating platelet function, highlighting the possible implications in activation and aggregation.

Immunomodulatory role of glycoRNAs in the brain

Glycosylation of lipids and proteins significantly increases the molecular diversity in the brain. Membrane-localized glycoconjugates facilitate critical neuro-immune interactions. Therefore, glycodysregulation is increasingly recognized as a novel hallmark of various acute and chronic neurological diseases. Although RNAs are heavily modified, they are never thought to be substrates for glycosylation due to their inaccessibility to the glycosylation machinery in the Golgi apparatus. The astonishing discovery of cell surface glycoRNAs opened new avenues for glycomedicine. This review highlighted the key features of GlycoRNAs and further discussed their potential immunomodulatory role in the brain, particularly focusing on post-stroke neuroinflammation.

Ticagrelor Resistance in Cardiovascular Disease and Ischemic Stroke

Ticagrelor, acting as a reversible platelet aggregation inhibitor of P2Y12 receptors (P2Y12R), is regarded as one of the first-line antiplatelet drugs for acute cardiovascular diseases. Though the probability of ticagrelor resistance is much lower than that of clopidogrel, there have been recent reports of ticagrelor resistance. In this review, we summarized the clinical application of ticagrelor and then presented the criteria and current status of ticagrelor resistance. We further discussed the potential mechanisms for ticagrelor resistance in terms of drug absorption, metabolism, and receptor action. In conclusion, the incidences of ticagrelor resistance fluctuated between 0 and 20%, and possible mechanisms mainly arose from its absorption and receptor action. Specifically, a variety of factors, such as the drug form of ticagrelor, gut microecology, and the expression and function of P-glycoprotein (P-gp) and P2Y12R, have been shown to be associated with ticagrelor resistance. The exact mechanisms of ticagrelor resistance warrant further exploration, which may contribute to the diagnosis and treatment of ticagrelor resistance.

The Function and Regulation of Platelet P2Y12 Receptor

In addition to the key role in hemostasis and thrombosis, platelets have also been wildly acknowledged as immune regulatory cells and involving in the pathogenesis of inflammation-related diseases. Since purine receptor P2Y12 plays a crucial role in platelet activation, P2Y12 antagonists such as clopidogrel, prasugrel, and ticagrelor have been widely used in cardiovascular diseases worldwide in recent decades due to their potent antiplatelet and antithrombotic effects. Meanwhile, the role of P2Y12 in inflammatory diseases has also been extensively studied. Relatively, there are few studies on the regulation of P2Y12. This review first summarizes the various roles of P2Y12 in the process of platelet activation, as well as downstream effects and signaling pathways; then introduces the effects of P2Y12 in inflammatory diseases such as sepsis, atherosclerosis, cancer, autoimmune diseases, and asthma; and finally reviews the current researches on P2Y12 regulation.

Interaction of Cardiovascular Nonmodifiable Risk Factors, Comorbidities and Comedications With Ischemia/Reperfusion Injury and Cardioprotection by Pharmacological Treatments and Ischemic Conditioning

Preconditioning, postconditioning, and remote conditioning of the myocardium enhance the ability of the heart to withstand a prolonged ischemia/reperfusion insult and the potential to provide novel therapeutic paradigms for cardioprotection. While many signaling pathways leading to endogenous cardioprotection have been elucidated in experimental studies over the past 30 years, no cardioprotective drug is on the market yet for that indication. One likely major reason for this failure to translate cardioprotection into patient benefit is the lack of rigorous and systematic preclinical evaluation of promising cardioprotective therapies prior to their clinical evaluation, since ischemic heart disease in humans is a complex disorder caused by or associated with cardiovascular risk factors and comorbidities. These risk factors and comorbidities induce fundamental alterations in cellular signaling cascades that affect the development of ischemia/reperfusion injury and responses to cardioprotective interventions. Moreover, some of the medications used to treat these comorbidities may impact on cardioprotection by again modifying cellular signaling pathways. The aim of this article is to review the recent evidence that cardiovascular risk factors as well as comorbidities and their medications may modify the response to cardioprotective interventions. We emphasize the critical need for taking into account the presence of cardiovascular risk factors as well as comorbidities and their concomitant medications when designing preclinical studies for the identification and validation of cardioprotective drug targets and clinical studies. This will hopefully maximize the success rate of developing rational approaches to effective cardioprotective therapies for the majority of patients with multiple comorbidities. SIGNIFICANCE STATEMENT: Ischemic heart disease is a major cause of mortality; however, there are still no cardioprotective drugs on the market. Most studies on cardioprotection have been undertaken in animal models of ischemia/reperfusion in the absence of comorbidities; however, ischemic heart disease develops with other systemic disorders (e.g., hypertension, hyperlipidemia, diabetes, atherosclerosis). Here we focus on the preclinical and clinical evidence showing how these comorbidities and their routine medications affect ischemia/reperfusion injury and interfere with cardioprotective strategies.

Peripheral blood RNA biomarkers for cardiovascular disease from bench to bedside: a position paper from the EU-CardioRNA COST action CA17129

Despite significant advances in the diagnosis and treatment of cardiovascular diseases, recent calls have emphasized the unmet need to improve precision-based approaches in cardiovascular disease. Although some studies provide preliminary evidence of the diagnostic and prognostic potential of circulating coding and non-coding RNAs, the complex RNA biology and lack of standardization have hampered the translation of these markers into clinical practice. In this position paper of the CardioRNA COST action CA17129, we provide recommendations to standardize the RNA development process in order to catalyse efforts to investigate novel RNAs for clinical use. We list the unmet clinical needs in cardiovascular disease, such as the identification of high-risk patients with ischaemic heart disease or heart failure who require more intensive therapies. The advantages and pitfalls of the different sample types, including RNAs from plasma, extracellular vesicles, and whole blood, are discussed in the sample matrix, together with their respective analytical methods. The effect of patient demographics and highly prevalent comorbidities, such as metabolic disorders, on the expression of the candidate RNA is presented and should be reported in biomarker studies. We discuss the statistical and regulatory aspects to translate a candidate RNA from a research use only assay to an in-vitro diagnostic test for clinical use. Optimal planning of this development track is required, with input from the researcher, statistician, industry, and regulatory partners.

Plasma levels of platelet-enriched microRNAs change during antiplatelet therapy in healthy subjects

Platelets are the main effectors of primary hemostasis but also cause thrombosis in pathological conditions. Antiplatelet drugs are the cornerstone for the prevention of adverse cardiovascular events. Monitoring the extent of platelet inhibition is essential. Currently available platelet function tests come with constraints, limiting use in antiplatelet drug development as well as in clinical routine. With this study, we aim to investigate whether plasma miRNAs might be suitable biomarkers for monitoring antiplatelet treatment. Platelet-poor plasma was obtained from a trial including 87 healthy male volunteers that either received ticagrelor (n = 44) or clopidogrel (n = 43). Blood was collected before drug intake and after 2 h, 6 h, and 24 h. We measured a panel of 11 platelet-enriched miRNAs (thrombomiRs) by RT-qPCR and selected four biomarker candidates (i.e., miR-223-3p, miR-150-5p, miR-126-3p, miR-24-3p). To further characterize those miRNAs, we performed correlation analyses with the number of extracellular vesicles and clotting time dependent on procoagulant vesicles (PPL assay). We show that platelet-enriched miRNAs in the circulation are significantly reduced upon P2Y12-mediated platelet inhibition. This effect occurred fast, reaching its peak after 2 h. Additionally, we demonstrate that higher baseline levels of thrombomiRs are linked to a stronger reduction upon antiplatelet therapy. Finally, we show that miRNAs from our panel might be the cargo of platelet-derived and procoagulant vesicles. In conclusion, we provide evidence that thrombomiR levels change within 2 h after pharmacological platelet inhibition and circulate the body within platelet-derived and procoagulant extracellular vesicles, rendering them potential biomarker candidates for the assessment of in vivo platelet function.

microRNAs Associated with Carotid Plaque Development and Vulnerability: The Clinician's Perspective

Ischemic stroke (IS) related to atherosclerosis of large arteries is one of the leading causes of mortality and disability in developed countries. Atherosclerotic internal carotid artery stenosis (ICAS) contributes to 20% of all cerebral ischemia cases. Nowadays, atherosclerosis prevention and treatment measures aim at controlling the atherosclerosis risk factors, or at the interventional (surgical or endovascular) management of mature occlusive lesions. There is a definite lack of the established circulating biomarkers which, once modulated, could prevent development of atherosclerosis, and consequently prevent the carotid-artery-related IS. Recent studies emphasize that microRNA (miRNA) are the emerging particles that could potentially play a pivotal role in this approach. There are some research studies on the association between the expression of small non-coding microRNAs with a carotid plaque development and vulnerability. However, the data remain inconsistent. In addition, all major studies on carotid atherosclerotic plaque were conducted on cell culture or animal models; very few were conducted on humans, whereas the accumulating evidence demonstrates that it cannot be automatically extrapolated to processes in humans. Therefore, this paper aims to review the current knowledge on how miRNA participate in the process of carotid plaque formation and rupture, as well as stroke occurrence. We discuss potential target miRNA that could be used as a prognostic or therapeutic tool.

Research progress on the role of exosomes in obstructive sleep apnea-hypopnea syndrome-related atherosclerosis

Cardiovascular disease (CVD) is a leading cause of mortality worldwide. Atherosclerosis, a multifactorial disease with complicated pathogenesis, is the main cause of CVD, underlying several major adverse cardiovascular events. Obesity is the main cause of obstructive sleep apnea (OSA) and a significant risk for atherosclerosis. OSA is an independent risk factor for CVD. Recent research has focused on understanding the underlying molecular mechanisms by which OSA influences atherosclerosis pathogenesis. The role of exosomes in this process has attracted considerable attention. Exosomes are a type of extracellular vesicles (EV) that are released from many cells (both healthy and diseased) and mediate cell-to-cell communication by transporting microRNAs (miRNAs), proteins, mRNAs, DNA, or lipids to target cells, thereby modulating the functions of target cells and tissues. Intermittent hypoxia in OSA alters the exosomal carrier in circulation and promotes the permeability and dysfunction of endothelial cells, which have been associated with the pathogenesis of atherosclerosis. This review discusses the potential roles of exosomes and exosome-derived molecules in the development and progression of OSA-related atherosclerosis. Additionally, we explore the possible mechanisms underlying OSA-related atherosclerosis and provide new insights for the development of novel exosome-based therapeutics for OSA-related atherosclerosis and CVD.

Clinical Application of Serum microRNAs in Atherosclerotic Coronary Artery Disease

MicroRNAs (miRs) are promising diagnostic, prognostic and therapeutic biomolecules for atherosclerotic cardiovascular disease. Atherosclerotic occlusive disease concerns a large population of patients, carrying the highest incidence of fatal and non-fatal adverse events, such as myocardial infarction, ischemic stroke, and limb ischemia, worldwide. Consistently, miRs are involved in regulation and pathogenesis of atherosclerotic coronary artery disease (CAD), acute coronary syndromes (ACS), both with ST-segment (STEMI) and non-ST segment elevation myocardial infarctions (NSTEMI), as well as cardiac remodeling and fibrosis following ACS. However, the genetic and molecular mechanisms underlying adverse outcomes in CAD are multifactorial, and sometimes difficult to interpret for clinicians. Therefore, in the present review paper we have focused on the clinical meaning and the interpretation of various miRs findings, and their potential application in routine clinical practice.

Insights Into Platelet-Derived MicroRNAs in Cardiovascular and Oncologic Diseases: Potential Predictor and Therapeutic Target

Non-communicable diseases (NCDs), represented by cardiovascular diseases and cancer, have been the leading cause of death globally. Improvements in mortality from cardiovascular (CV) diseases (decrease of 14%/100,000, United States) or cancers (increase 7.5%/100,000, United States) seem unsatisfactory during the past two decades, and so the search for innovative and accurate biomarkers of early diagnosis and prevention, and novel treatment strategies is a valuable clinical and economic endeavor. Both tumors and cardiovascular system are rich in angiological systems that maintain material exchange, signal transduction and distant regulation. This pattern determines that they are strongly influenced by circulating substances, such as glycolipid metabolism, inflammatory homeostasis and cyclic non-coding RNA and so forth. Platelets, a group of small anucleated cells, inherit many mature proteins, mRNAs, and non-coding RNAs from their parent megakaryocytes during gradual formation and manifest important roles in inflammation, angiogenesis, atherosclerosis, stroke, myocardial infarction, diabetes, cancer, and many other diseases apart from its classical function in hemostasis. MicroRNAs (miRNAs) are a class of non-coding RNAs containing ∼22 nucleotides that participate in many key cellular processes by pairing with mRNAs at partially complementary binding sites for post-transcriptional regulation of gene expression. Platelets contain fully functional miRNA processors in their microvesicles and are able to transport their miRNAs to neighboring cells and regulate their gene expression. Therefore, the importance of platelet-derived miRNAs for the human health is of increasing interest. Here, we will elaborate systematically the roles of platelet-derived miRNAs in cardiovascular disease and cancer in the hope of providing clinicians with new ideas for early diagnosis and therapeutic strategies.

Alteration of circulating platelet-related and diabetes-related microRNAs in individuals with type 2 diabetes mellitus: a stepwise hypoglycaemic clamp study

BACKGROUND

In patients with type 2 diabetes mellitus (T2DM) an association between severe hypoglycaemic episodes and the risk of cardiovascular (CV) morbidity and mortality has been previously established.

METHODS

We aimed to investigate the influence of hypoglycaemia on several diabetes-related and platelet-related miRNAs selected based on bioinformatic analysis and literature search, including hsa-miR-16, hsa-miR-34a, hsa-miR-129-2, hsa-miR-15a, hsa-miR-15b, hsa-miR-106a, miR-223, miR-126. Selected miRNAs were validated by qRT-PCR in 14 patients with T2DM on metformin monotherapy, without established CV disease and antiplatelet therapy during a stepwise hypoglycaemic clamp experiment and a follow-up 7 days after the clamp event. In order to identify which pathways and phenotypes are associated with validated miRNAs we performed target prediction on genes expressed with high confidence in platelets.

RESULTS

Circulating levels of miR-106a-5p, miR-15b, miR-15a, miR-16-5p, miR-223 and miR-126 were increased after euglycaemic clamp followed by hypoglycaemic clamp, each with its distinctive time trend. On the contrary, miR-129-2-3p, miR-92a-3p and miR-34a-3p remained unchanged. MiR-16-5p was negatively correlated with interleukin (IL)-6, intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) (p = 0.002, p < 0.001, p = 0.016, respectively), whereas miR-126 was positively correlated with VCAM (p < 0.001). There were negative correlations between miR-16-5p, miR-126 and coagulation factors, including factor VIII and von Willebrand factor (vWF). Among all studied miRNAs, miR-126, miR-129-2-3p and miR-15b showed correlation with platelet function. Bioinformatic analysis of platelet-related targets of analyzed miRNAs showed strong enrichment of IL-2 signaling. We also observed significant enrichment of pathways and diseases related to cancer, CV diseases, hyperglycemia, and neurological diseases.

CONCLUSIONS

Hypoglycaemia can significantly influence the expression of platelet-enriched miRNAs, with a time trend paralleling the time course of platelet activation. This suggests miRNAs could be exploited as biomarkers for platelet activation in response to hypoglycaemia, as they are probably released by platelets upon activation by hypoglycaemic episodes. Should they hold their promise in clinical endpoint studies, platelet-derived miRNAs might become helpful markers of CV risk in subjects with diabetes. Trial registration The study was registered at clinical trials.gov; Impact of Hypoglycaemia in Patients With DIAbetes Mellitus Type 2 on PLATElet Activation (Diaplate), trial number: NCT03460899.

miR-486-5p and miR-22-3p Enable Megakaryocytic Differentiation of Hematopoietic Stem and Progenitor Cells without Thrombopoietin

Megakaryocytes release submicron size microparticles (MkMPs) in circulation. We have shown that MkMPs target CD34+ hematopoietic stem/progenitor cells (HSPCs) to induce megakaryocytic differentiation, and that small RNAs in MkMPs play an important role in the development of this phenotype. Here, using single-molecule real-time (SMRT) RNA sequencing (RNAseq), we identify the synergetic effect of two microRNAs (miRs), miR-486-5p and miR-22-3p (highly enriched in MkMPs), in driving the Mk differentiation of HSPCs in the absence of thrombopoietin (TPO). Separately, our data suggest that the MkMP-induced Mk differentiation of HSPCs is enabled through JNK and PI3K/Akt/mTOR signaling. The interaction between the two signaling pathways is likely mediated by a direct target of miR-486-5p and a negative regulator of PI3K/Akt signaling, the phosphatase and tensin homologue (PTEN) protein. Our data provide a possible mechanistic explanation of the biological effect of MkMPs in inducing megakaryocytic differentiation of HSPCs, a phenotype of potential physiological significance in stress megakaryopoiesis.

Dysregulation in the Expression of Platelet Surface Receptors in Acute Coronary Syndrome Patients-Emphasis on P2Y12

The pathological conditions caused by blood platelet activation constitute a fundamental core in the pathogenesis of Acute Coronary Syndrome (ACS). The hyperactivity of platelets in ACS is well-documented, but there is still little research into the molecular basis of phenotypic changes in platelet functionality. To expand the knowledge of this phenomenon, we analyzed the disturbances in the expression of several key platelet receptors and the aspect of regulating potential abnormalities. Platelet surface receptors are responsible for maintaining the hemostatic balance, platelet interaction with immune cells, and support of the coagulation cascade leading to occlusion of the vessel lumen. Due to their prominent role, platelet receptors constitute a major target in pharmacological treatment. Our work aimed to identify the molecular alteration of platelet surface receptors, which showed augmented mRNA expression of P2Y12, GP1BB, ITGA2B, and ITGB3 and increased protein concentrations of P2Y12 and GP IIb/IIIa in ACS. The upregulation of the P2Y12 level was also confirmed by confocal and cytometric visualization. Furthermore, we evaluated the expression of two microRNAs: miR-223-3p and miR-126-3p, which were suggested to regulate platelet P2Y12 expression. Results of our study present new insight into the molecular background of ACS.

Selective sorting and secretion of hY4 RNA fragments into extracellular vesicles mediated by methylated YBX1 to promote lung cancer progression

BACKGROUND

Extracellular vesicles (EVs) are emerging mediators of intercellular communication that have been shown to play important roles in tumor progression. YRNA fragments, a type of small non-coding RNA, are dysregulated in non-small cell lung cancer (NSCLC) cell-derived EVs, suggesting that they may be an effective biomarker for cancer diagnosis and treatment strategies.

METHODS

Differentially expressed YRNA hY4 fragments (hY4F) in EVs from NSCLC cells and normal lung fibroblasts were isolated by differential ultra-centrifugation. RNA-binding proteins that interacted with hY4F were identified by screening with an RNA pulldown assay and mass spectrometry. The molecular mechanism of hY4F and the RNA-binding protein Y box binding protein 1 (YBX1) was demonstrated by qRT-PCR, western blot, RNA pulldown, and rescue experiments. Transcriptome sequencing, qRT-PCR validation, bioinformatics analysis and NF-κB pathway inhibitor assays elucidate the mechanism of YBX1 and hY4F inhibiting lung cancer. A peptide pulldown assay was performed to screen and identify a potential methyltransferase for YBX1. The roles of hY4F, YBX1, and SET domain containing 3 in biological functions, such as proliferation, migration, invasion, and apoptosis, in lung cancer cells were also examined by EdU incorporation assay, Transwell assay, flow cytometry, and other methods. Lastly, a mouse xenograft assay was used to assess the clinical relevance of YBX1 and hY4F in vivo.

RESULTS

Our data demonstrate that hY4 RNA fragments were upregulated in lung cancer- derived EVs, hY4F inhibits tumor progression through downregulating MAPK/NF-κB signaling, and then the selective sorting and secretion of hY4F into lung cancer EVs is regulated by the RNA-binding protein YBX1. Furthermore, we identified lysine K264 within the YBX1 C-terminal domain as the necessary site for its interaction with hY4Fs. K264 is modified by methylation, which affects its binding to hY4F and subsequent selective sorting into EVs in lung cancer cells.

CONCLUSION

Our findings demonstrate that hY4F acts as a tumor suppressor and is selectively sorted into lung cancer cell-derived EVs by interacting with methylated YBX1, which in turn promotes lung cancer progression. hY4F is a promising circulating biomarker for non-small cell lung cancer diagnosis and prognosis and an exceptional candidate for further therapeutic exploration.

Comprehensive Characterization of Platelet-Enriched MicroRNAs as Biomarkers of Platelet Activation

Dysregulation of platelet function is causally connected to thrombus formation and cardiovascular diseases. Therefore, assessing platelet reactivity is crucial. However, current platelet function tests come with pitfalls, limiting clinical use. Plasma miRNA signatures have been suggested as novel biomarkers for predicting/diagnosing cardiovascular diseases and monitoring antiplatelet therapy. Here, we provide results from a comprehensive study on the feasibility of using circulatory platelet miRNAs as surrogate markers of platelet activation. We performed small RNA-Seq on different blood cell types to confirm known and identify novel platelet-enriched miRNAs and validated a panel of 16 miRNAs using RT-qPCR. To identify the main carrier of these blood-based platelet miRNAs, we enriched and analyzed distinct microvesicle populations. Platelets were stimulated with GPVI and P2Y12 agonists in vitro to monitor the release of the selected miRNAs following activation. Finally, the miRNA panel was also measured in plasma from mice undergoing the Folts intervention (recurrent thrombus formation in the carotid artery). Applying an unbiased bioinformatics-supported workflow to our NGS data, we were able to confirm a panel of previously established miRNA biomarker candidates and identify three new candidates (i.e., miR-199a-3p, miR-151a-5p, and miR-148b-3p). Basal levels of platelet-derived miRNAs in plasma were mainly complexed with proteins, not extracellular vesicles. We show that changes in miRNA levels due to platelet activation are detectable using RT-qPCR. In addition, we highlight limitations of studying the in vitro release of miRNAs from platelets. In vivo thrombosis resulted in significant elevations of platelet-derived miRNA levels in mice. In conclusion, we provide in-depth evidence that activated platelets release miRNAs, resulting in measurable changes in circulatory miRNA levels, rendering them promising biomarker candidates.

Circulating and Platelet MicroRNAs in Cardiovascular Risk Assessment and Antiplatelet Therapy Monitoring

Micro-ribonucleic acids (microRNAs) are small molecules that take part in the regulation of gene expression. Their function has been extensively investigated in cardiovascular diseases (CVD). Most recently, miRNA expression levels have been suggested as potential biomarkers of platelet reactivity or response to antiplatelet therapy and tools for risk stratification for recurrence of ischemic evens. Among these, miR-126 and miR-223 have been found to be of particular interest. Despite numerous studies aimed at understanding the prognostic value of miRNA levels, no final conclusions have been drawn thus far regarding their utility in clinical practice. The aim of this review is to critically appraise the evidence on the association between miRNA expression, cardiovascular risk and on-treatment platelet reactivity as well as provide insights on future developments in the field.

Factors Associated with Platelet Activation-Recent Pharmaceutical Approaches

Platelets are at the forefront of human health and disease following the advances in their research presented in past decades. Platelet activation, their most crucial function, although beneficial in the case of vascular injury, may represent the initial step for thrombotic complications characterizing various pathologic states, primarily atherosclerotic cardiovascular diseases. In this review, we initially summarize the structural and functional characteristics of platelets. Next, we focus on the process of platelet activation and its associated factors, indicating the potential molecular mechanisms involving inflammation, endothelial dysfunction, and miRs. Finally, an overview of the available antiplatelet agents is being portrayed, together with agents possessing off-set platelet-inhibitory actions, while an extensive presentation of drugs under investigation is being given.

Dissecting the transcriptome in cardiovascular disease

The human transcriptome comprises a complex network of coding and non-coding RNAs implicated in a myriad of biological functions. Non-coding RNAs exhibit highly organized spatial and temporal expression patterns and are emerging as critical regulators of differentiation, homeostasis, and pathological states, including in the cardiovascular system. This review defines the current knowledge gaps, unmet methodological needs, and describes the challenges in dissecting and understanding the role and regulation of the non-coding transcriptome in cardiovascular disease. These challenges include poor annotation of the non-coding genome, determination of the cellular distribution of transcripts, assessment of the role of RNA processing and identification of cell-type specific changes in cardiovascular physiology and disease. We highlight similarities and differences in the hurdles associated with the analysis of the non-coding and protein-coding transcriptomes. In addition, we discuss how the lack of consensus and absence of standardized methods affect reproducibility of data. These shortcomings should be defeated in order to make significant scientific progress and foster the development of clinically applicable non-coding RNA-based therapeutic strategies to lessen the burden of cardiovascular disease.

Circulating microRNAs as biomarkers and mediators of platelet activation

Platelets are essential mediators of physiological hemostasis and pathological thrombosis. Currently available tests and markers of platelet activation did not prove successful in guiding treatment decisions for patients with cardiovascular disease, justifying further research into novel markers of platelet reactivity. Platelets contain a variety of microRNAs (miRNAs) and are a major contributor to the extracellular circulating miRNA pool. Levels of platelet-derived miRNAs in the circulation have been associated with different measures of platelet activation as well as antiplatelet therapy and have therefore been implied as potential new markers of platelet reactivity. In contrast to the ex vivo assessment of platelet reactivity by current platelet function tests, miRNA measurements may enable assessment of platelet reactivity in vivo. It remains to be seen however, whether miRNAs may aid clinical diagnostics. Major limitations in the platelet miRNA research field remain the susceptibility to preanalytical variation, non-standardized sample preparation and data normalization that hampers inter-study comparisons. In this review, we provide an overview of the literature on circulating miRNAs as biomarkers of platelet activation, highlighting the underlying biology, the application in patients with cardiovascular disease and antiplatelet therapy and elaborating on technical limitations regarding their quantification in the circulation.

AMD Genomics: Non-Coding RNAs as Biomarkers and Therapeutic Targets

Age-related macular degeneration (AMD) is a progressive neurodegenerative disease that is the world’s leading cause of blindness in the aging population. Although the clinical stages and forms of AMD have been elucidated, more specific prognostic tools are required to determine when patients with early and intermediate AMD will progress into the advanced stages of AMD. Another challenge in the field has been the appropriate development of therapies for intermediate AMD and advanced atrophic AMD. After numerous negative clinical trials, an anti-C5 agent and anti-C3 agent have recently shown promising results in phase 3 clinical trials, in terms of slowing the growth of geographic atrophy, an advanced form of AMD. Interestingly, both drugs appear to be associated with an increased incidence of wet AMD, another advanced form of the disease, and will require frequent intravitreal injections. Certainly, there remains a need for other therapeutic agents with the potential to prevent progression to advanced stages of the disease. Investigation of the role and clinical utility of non-coding RNAs (ncRNAs) is a major advancement in biology that has only been minimally applied to AMD. In the following review, we discuss the clinical relevance of ncRNAs in AMD as both biomarkers and therapeutic targets.

A guide to molecular and functional investigations of platelets to bridge basic and clinical sciences

Platelets have been shown to be associated with pathophysiological process beyond thrombosis, demonstrating critical additional roles in homeostatic processes, such as immune regulation, and vascular remodeling. Platelets themselves can have multiple functional states and can communicate and regulate other cells including immune cells and vascular smooth muscle cells, to serve such diverse functions. Although traditional platelet functional assays are informative and reliable, they are limited in their ability to unravel platelet phenotypic heterogeneity and interactions. Developments in methods such as electron microscopy, flow cytometry, mass spectrometry, and 'omics' studies, have led to new insights. In this Review, we focus on advances in platelet biology and function, with an emphasis on current and promising methodologies. We also discuss technical and biological challenges in platelet investigations. Using coronavirus disease 2019 (COVID-19) as an example, we further describe the translational relevance of these approaches and the possible 'bench-to-bedside' utility in patient diagnosis and care.

Deciphering the roles of miR-16-5p in Malignant Solid Tumorsmalignant solid tumors

MiR-16-5p, a member of the miR-16 family, has been reported to be abnormal expression in tumor tissues and blood of tumor patients, and also downregulated in most cancer cell lines. Aberrant expression of miR-16-5p promotes tumor cell proliferation, invasion, metastasis, angiogenesis, and can also affect the treatment sensitivity, such as radiotherapy and chemotherapy. Generally, miR-16-5p plays an anti-tumor role and these diverse functions of miR-16-5p in tumors collectively indicate that miR-16-5p may become an attractive target for novel anticancer therapies and a powerful diagnostic and prognostic biomarker for early tumor detection and population risk screening. Herein we review the role and utilization of miR-16-5p in malignant tumor in detail.

Association of cardiometabolic microRNAs with COVID-19 severity and mortality

AIMS

Coronavirus disease 2019 (COVID-19) can lead to multiorgan damage. MicroRNAs (miRNAs) in blood reflect cell activation and tissue injury. We aimed to determine the association of circulating miRNAs with COVID-19 severity and 28 day intensive care unit (ICU) mortality.

METHODS AND RESULTS

We performed RNA-Seq in plasma of healthy controls (n = 11), non-severe (n = 18), and severe (n = 18) COVID-19 patients and selected 14 miRNAs according to cell- and tissue origin for measurement by reverse transcription quantitative polymerase chain reaction (RT-qPCR) in a separate cohort of mild (n = 6), moderate (n = 39), and severe (n = 16) patients. Candidates were then measured by RT-qPCR in longitudinal samples of ICU COVID-19 patients (n = 240 samples from n = 65 patients). A total of 60 miRNAs, including platelet-, endothelial-, hepatocyte-, and cardiomyocyte-derived miRNAs, were differentially expressed depending on severity, with increased miR-133a and reduced miR-122 also being associated with 28 day mortality. We leveraged mass spectrometry-based proteomics data for corresponding protein trajectories. Myocyte-derived (myomiR) miR-133a was inversely associated with neutrophil counts and positively with proteins related to neutrophil degranulation, such as myeloperoxidase. In contrast, levels of hepatocyte-derived miR-122 correlated to liver parameters and to liver-derived positive (inverse association) and negative acute phase proteins (positive association). Finally, we compared miRNAs to established markers of COVID-19 severity and outcome, i.e. SARS-CoV-2 RNAemia, age, BMI, D-dimer, and troponin. Whilst RNAemia, age and troponin were better predictors of mortality, miR-133a and miR-122 showed superior classification performance for severity. In binary and triplet combinations, miRNAs improved classification performance of established markers for severity and mortality.

CONCLUSION

Circulating miRNAs of different tissue origin, including several known cardiometabolic biomarkers, rise with COVID-19 severity. MyomiR miR-133a and liver-derived miR-122 also relate to 28 day mortality. MiR-133a reflects inflammation-induced myocyte damage, whilst miR-122 reflects the hepatic acute phase response.

Diagnostic Potential of Exosomal HypoxamiRs in the Context of Hypoxia-Sumoylation-HypoxamiRs in Early Onset Preeclampsia at the Preclinical Stage

As the search for non-invasive preclinical markers of preeclampsia (PE) expands, the number of studies on the diagnostic potential of exosomes is growing. Changes in the partial pressure of oxygen caused by impaired uteroplacental perfusion in PE are a powerful inducer of increased production and release of exosomes from cells, which also determine their cargo. At the same time, the expression pattern of oxygen-dependent microRNAs (miRNAs), called "hypoxamiRs", is modulated, and their packing into exosomes is strictly regulated by sumoylation. In connection therewith, we emphasize the evaluation of exosomal hypoxamiR expression (miR-27b-3p, miR-92b-3p, miR-181a-5p, and miR-186-5p) using quantitative RT-PCR, as well as SUMO 1-4 and UBC9 (by Western blotting), in pregnant women with early-onset PE. The findings show that miR-27b-3p and miR-92b-3p expression was significantly changed at 11-14 and 24-26 weeks of gestation in the blood plasma of pregnant women with early-onset PE, which subsequently manifested. High sensitivity and specificity (AUC = 1) were demonstrated for these miRNAs in the first trimester, and significant correlations with a decrease in hemoglobin (r = 0.71, p = 0.002; r = -0.71, p = 0.002) were established. In mid-pregnancy, the miR-27b-3p expression was found to correlate with an increase in platelets (r = -0.95, p = 0.003), and miR-92b-3p was associated with a decrease in the prothrombin index (r = 0.95, p = 0.003). Specific exomotifs of studied miRNAs were also identified, to which the sumoylated ribonucleoprotein hnRNPA2/B1 binds, carrying out their packaging into exosomes. The expression of conjugated SUMO 1 (p = 0.05), SUMO 2/3/4 (p = 0.03), and UBC9 (p = 0.1) was increased in exosomes at early-onset PE, and the expression of free SUMO 1 (p = 0.03) and SUMO 2/3/4 (p = 0.01) was significantly increased in the placenta, as an adaptive response to hypoxia. Moreover, SUMO 2/3/4 was negatively correlated with miR-27b-3p expression in the placenta. In conclusion, the diagnostic potential of exosomal hypoxamiRs mediated by sumoylation may form the basis for the development of combined specific targets for the treatment of early-onset PE, as hnRNPA2/B1 is a target of miR-27b-3p, and its sumoylation creates miR-27b-3p-hnRNPA2/B1-SUMO 1-4 cross-talk.

MicroRNAs as Novel Biomarkers for P2Y12 - Inhibitors Resistance Prediction

AIM

The aim of this study is to assess 6 micro-RNAs: miR-126, miR-223, miR-150, miR-29, miR-34, miR-142 as potential biomarkers for P2Y12- inhibitors resistance prediction.

METHODS

Eighty patients with an acute coronary syndrome undergoing percutaneous coronary intervention treated in a multidisciplinary hospital in Moscow with DAPT (either with ticagrelor, n=45, or clopidogrel, n=35) were enrolled. The carriership of 6 clinically relevant polymorphisms for ticagrelor and 17 for clopidogrel was detected. Expression levels of six prospective miRNAs were measured. The activity of CYP3A4 isoenzyme was measured as the ratio of the concentrations of cortisol and 6β-hydroxycortisol.

RESULTS

The polymorphisms of the P2Y12-inhibitors ADME genes that demonstrated statistically significant connection with miRNA expression levels are as follows: P2Y12R (A>G, rs3732759) and miR-29 (p=0.017), miR-34 (p=0.003); CYP2C19*17 (C-806T, rs1224856) and miR-142 (p=0.012); PON1 (Q192R, rs662) and miR-29 (p=0.004), ABCG2 (G>T, rs2231142) and miR-34 (p=0.007). MiRNAs expression levels showed connection with the results of the platelet reactivity assessment by utilizing VerifyNow assay ("Instrumentation laboratory", MA, US). MiR-126 (β coefficient=-0.076, SE=0.032, p=0.021), miR-223 (β coefficient=-0.089, SE=0.041, p=0.032), miR-29 (β coefficient=-0.042, SE=0.018, p=0.026), miR-142 (β coefficient=-0.072, SE=0.026, p=0.008) have the potential to be used as biomarkers and may substitute platelet reactivity testing.

CONCLUSION

This study has revealed new biomarkers for P2Y12-inhibitors resistance testing: miR-29, miR-34, miR-126, miR-142, miR-223.

Sex-Specific MicroRNAs in Neurovascular Units in Ischemic Stroke

Accumulating evidence pinpoints sex differences in stroke incidence, etiology and outcome. Therefore, more understanding of the sex-specific mechanisms that lead to ischemic stroke and aggravation of secondary damage after stroke is needed. Our current mechanistic understanding of cerebral ischemia states that endothelial quiescence in neurovascular units (NVUs) is a major physiological parameter affecting the cellular response to neuron, astrocyte and vascular smooth muscle cell (VSMC) injury. Although a hallmark of the response to injury in these cells is transcriptional activation, noncoding RNAs such as microRNAs exhibit cell-type and context dependent regulation of gene expression at the post-transcriptional level. This review assesses whether sex-specific microRNA expression (either derived from X-chromosome loci following incomplete X-chromosome inactivation or regulated by estrogen in their biogenesis) in these cells controls NVU quiescence, and as such, could differentiate stroke pathophysiology in women compared to men. Their adverse expression was found to decrease tight junction affinity in endothelial cells and activate VSMC proliferation, while their regulation of paracrine astrocyte signaling was shown to neutralize sex-specific apoptotic pathways in neurons. As such, these microRNAs have cell type-specific functions in astrocytes and vascular cells which act on one another, thereby affecting the cell viability of neurons. Furthermore, these microRNAs display actual and potential clinical implications as diagnostic and prognostic biomarkers in ischemic stroke and in predicting therapeutic response to antiplatelet therapy. In conclusion, this review improves the current mechanistic understanding of the molecular mechanisms leading to ischemic stroke in women and highlights the clinical promise of sex-specific microRNAs as novel diagnostic biomarkers for (silent) ischemic stroke.

Association of Genetic Variants in miR-217 Gene with Risk of Coronary Artery Disease: A Case-Control Study

Objective

To evaluate the associations of genetic variants of the miR-217 gene with coronary artery disease (CAD) risk, as well as plasma level of vascular endothelial growth factor (VEGF).

Methods

A case-control study with 498 CAD patients and 499 frequency-matched healthy controls was conducted to evaluate the associations of four tagSNPs of the miR-217 gene, including rs6724872, rs4999828, rs10206823, and rs41291177, with CAD risk and plasma level of VEGF.

Results

SNP rs6724872 and rs4999828 were significantly associated with increased risk of CAD (P value was smaller than 0.05 even after Bonferroni multiple adjustment). Compared with the G allele, C allele of rs6724872 was significantly associated with 1.73-fold increased risk of CAD (95% CI: 1.25-2.39; P = 0.001). While C allele of rs4999828 was significantly associated with 1.75-fold increased risk of CAD, compared with T allele (95% CI: 1.34-2.29; P = 4 × 10^-5). Meanwhile, rs6724872 and rs4999828 were also significantly associated with higher level of VEGF (P < 0.001).

Conclusion

These findings highlighted the important role of genetic variants of the miR-217 gene in the pathogenesis of CAD and potential targets for intervention.

Long non-coding RNAs in diabetic wound healing: Current research and clinical relevance

Diabetic wounds are a protracted complication of diabetes mainly characterised by chronic inflammation, obstruction of epithelialization, damaged blood vessels and collagen production (maturation), as well as neuropathy. As a non‐coding RNA (ncRNA) that lack coding potential, long non‐coding RNAs (lncRNAs) have recently been reported to play a salient role in diabetic wound healing. Here, this review summarises the roles of lncRNAs in the pathology and treatments of diabetic wounds, providing references for its potential clinical diagnostic criteria or therapeutic targets in the future.

Do miRNAs Have a Role in Platelet Function Regulation?

MicroRNAs (miRNAs) are a class of non-coding RNAs known to repress mRNA translation and subsequent protein production. miRNAs are predicted to modulate many targets and are involved in regulating various cellular processes. Identifying their role in cell function regulation may allow circulating miRNAs to be used as diagnostic or prognostic markers of various diseases. Increasing numbers of clinical studies have shown associations between circulating miRNA levels and platelet reactivity or the recurrence of cardiovascular events. However, these studies differed regarding population selection, sample types used, miRNA quantification procedures, and platelet function assays. Furthermore, they often lacked functional validation of the miRNA identified in such studies. The latter step is essential to identifying causal relationships and understanding if and how miRNAs regulate platelet function. This review describes recent advances in translational research dedicated to identifying miRNAs' roles in platelet function regulation.

MicroRNA as Biomarkers for Platelet Function and Maturity in Patients with Cardiovascular Disease

Patients with cardiovascular disease (CVD) are at increased risk of suffering myocardial infarction. Platelets are key players in thrombus formation and, therefore, antiplatelet therapy is crucial in the treatment and prevention of CVD. MicroRNAs (miRs) may hold the potential as biomarkers for platelet function and maturity. This systematic review was conducted using the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). To identify studies investigating the association between miRs and platelet function and maturity in patients with CVD, PubMed and Embase were searched on October 13 and December 13, 2020 without time boundaries. Risk of bias was evaluated using a standardized quality assessment tool. Of the 16 included studies, 6 studies were rated "good" and 10 studies were rated "fair." In total, 45 miRs correlated significantly with platelet function or maturity (rho ranging from -0.68 to 0.38, all p < 0.05) or differed significantly between patients with high platelet reactivity and patients with low platelet reactivity (p-values ranging from 0.0001 to 0.05). Only four miRs were investigated in more than two studies, namely miR-223, miR-126, miR-21 and miR-150. Only one study reported on the association between miRs and platelet maturity. In conclusion, a total of 45 miRs were associated with platelet function or maturity in patients with CVD, with miR-223 and miR-126 being the most frequently investigated. However, the majority of the miRs were only investigated in one study. More data are needed on the potential use of miRs as biomarkers for platelet function and maturity in CVD patients.

MiR-126-3p and MiR-223-3p as Biomarkers for Prediction of Thrombotic Risk in Patients with Acute Myocardial Infarction and Primary Angioplasty

Aim. This study was designed to evaluate the relationship between microRNAs (miRNAs), miR-126-3p and miR-223-3p, as new biomarkers of platelet activation, and predicting recurrent thrombotic events after acute myocardial infarction (AMI). Methods and Results. The analysis included 598 patients randomized in the PRAGUE-18 study (ticagrelor vs. prasugrel in AMI). The measurements of miRNAs were performed by using a novel miRNA immunoassay method. The association of miRNAs with the occurrence of the ischemic endpoint (EP) (cardiovascular death, nonfatal MI, or stroke) and bleeding were analyzed. The miR-223-3p level was significantly related to an increased risk of occurrence of the ischemic EP within 30 days (odds ratio (OR) = 15.74, 95% confidence interval (CI): 2.07-119.93, p = 0.008) and one year (OR = 3.18, 95% CI: 1.40-7.19, p = 0.006), respectively. The miR-126-3p to miR-223-3p ratio was related to a decreased risk of occurrence of EP within 30 days (OR = 0.14, 95% CI: 0.03-0.61, p = 0.009) and one year (OR = 0.37, 95% CI: 0.17-0.82, p = 0.014), respectively. MiRNAs were identified as independent predictors of EP even after adjustment for confounding clinical predictors. Adding miR-223-3p and miR-126-3p to miR-223-3p ratios as predictors into the model calculating the ischemic risk significantly increased the predictive accuracy for combined ischemic EP within one year more than using only clinical ischemic risk parameters. No associations between miRNAs and bleeding complications were identified. Conclusion. The miR-223-3p and the miR-126-3p are promising independent predictors of thrombotic events and can be used for ischemic risk stratification after AMI.