MicroRNAs in platelet function and cardiovascular disease

Analysis of the longitudinal stability of human plasma miRNAs and implications for disease biomarkers

There is great interest in developing clinical biomarker assays that can aid in non-invasive diagnosis and/or monitoring of human diseases, such as cancer, cardiovascular disease, and neurological diseases. Yet little is known about the longitudinal stability of miRNAs in human plasma. Here we assessed the intraindividual longitudinal stability of miRNAs in plasma from healthy human adults, and the impact of common factors (e.g., hemolysis, age) that may confound miRNA data. We collected blood by venipuncture biweekly over a 3-month period from 22 research participants who had fasted overnight, isolated total RNA, then performed miRNA qPCR. Filtering and normalization of the qPCR data revealed amplification of 134 miRNAs, 74 of which had high test-retest reliability and low percentage level drift, meaning they were stable in an individual over the 3-month time period. We also determined that, of nuisance factors, hemolysis and tobacco use have the greatest impact on miRNA levels and variance. These findings support that many miRNAs show intraindividual longitudinal stability in plasma from healthy human adults, including some reported as candidate biomarkers for Alzheimer's disease.

Research progress on microRNA in gout

Gout is a common form of arthritis caused by the deposition of sodium urate crystals in the joints and tissues around them. MicroRNAs (miRNAs) are noncoding RNAs that have been shown to be involved in regulating the pathogenesis of gout through multiple cellular signaling pathways, which may be potential targets for the treatment of gout. In this review, we systematically discuss the regulatory roles of related miRNAs in gout, which will provide help for the treatment of gout and miRNAs is expected to become a potential biomarker for gout diagnosis.

The application of proteomics and metabolomics to reveal the molecular mechanism of Nutmeg-5 in ameliorating cardiac fibrosis following myocardial infarction

BACKGROUND

Nutmeg-5, an ancient and classic formula in traditional Mongolian medicine comprising five kinds of traditional Chinese medicine, is widely used in the treatment of myocardial infarction (MI, called heart "Heyi" disease in Mongolian medicine). Cardiac fibrosis plays a critical role in the development and progression of heart failure after MI. However, the material basis and pharmacological mechanisms of the effect of Nutmeg-5 on cardiac fibrosis after MI remain unclear.

OBJECTIVE

The aim of this study was to first explore the potential material basis and molecular mechanism of action of Nutmeg-5 in improving cardiac fibrosis after MI via a multiomics approach.

METHODS

The constituents in Nutmeg-5 were identified by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). High-performance liquid chromatography (HPLC) and gas chromatography (GC)-based fingerprints of Nutmeg-5 were analysed, and characteristic peaks were identified by comparison to standard samples. A rat MI model was created by permanent ligation of the left anterior descending artery. The protective effect of Nutmeg-5 on cardiac fibrosis after MI was evaluated by tissue histology and measurement of the serum biomarkers of myocardial injury. Cardiac fibrosis levels were evaluated by Sirius red staining. Differentially expressed proteins in the myocardium and metabolites in the serum were explored by proteomic and untargeted metabolome analyses, respectively. Pearson correlation analysis was performed to explore the association between serum metabolites and myocardial proteins.

RESULTS

A total of 67 constituents were identified in Nutmeg-5 by UPLC-MS/MS. Sixteen components were identified in the fingerprint of Nutmeg-5 by comparison with a standard sample. Six lactones were isolated from Nutmeg-5 and quantified by HPLC and GC. MI was significantly alleviated in Nutmeg-5-treated rats compared to MI rats, as demonstrated by their decreased mortality, improved cardiac function, and attenuated cardiac fibrosis and myocardial injury. A total of 252 significant differential metabolites were identified in plasma between model and Nutmeg-5-treated rats by untargeted metabolome analysis. Among these, 36 critical metabolites were associated with Nutmeg-5 activity. Proteomic analysis identified 338 differentially expressed proteins in the rat myocardium between MI and Nutmeg-5-treated rats, including 204 upregulated and 134 downregulated proteins. Protein set enrichment analysis revealed that Nutmeg-5 treatment significantly inhibited the extracellular matrix (ECM)-receptor interaction pathway, which was activated in the myocardium of MI rats. A significant decrease in collagen and alpha smooth muscle actin expression levels was found in the myocardium of Nutmeg-5-treated rats compared to MI rats. These results illustrated that Nutmeg-5 had a significant protective effect on cardiac fibrosis after MI. A significant correlation was found between the ECM-receptor interaction pathway in the myocardium and critical metabolites in the serum. In addition, there were positive correlations between the levels of critical metabolites and the expression levels of transforming growth factor (TGF)-β1 and Smad2 in the rat myocardium.

CONCLUSIONS

Nutmeg-5 alleviated cardiac fibrosis after MI in rats by inhibiting the myocardial ECM-receptor interaction pathway and TGF-β1/Smad2 signalling, which was achieved by regulating plasma metabolites.

Mineralocorticoid Receptor Antagonists Mitigate Mitral Regurgitation-Induced Myocardial Dysfunction

Mitral regurgitation (MR), the disruption of the mitral valve, contributes to heart failure (HF). Under conditions of volume overload, excess mineralocorticoids promote cardiac fibrosis. The mineralocorticoid receptor antagonist spironolactone is a potassium-sparing diuretic and a guideline-recommended therapy for HF, but whether it can ameliorate degenerative MR remains unknown. Herein, we investigate the efficacy of spironolactone in improving cardiac remodeling in MR-induced HF compared with that of a loop diuretic, furosemide. Using a novel and mini-invasive technique, we established a rat model of MR. We treated the rats with spironolactone or furosemide for twelve weeks. The levels of cardiac fibrosis, apoptosis, and stress-associated proteins were then measured. In parallel, we compared the cardiac remodeling of 165 patients with degenerative MR receiving either spironolactone or furosemide. Echocardiography was performed at baseline and at six months. In MR rats treated with spironolactone, left ventricular function—especially when strained—and the pressure volume relationship significantly improved compared to those of rats treated with furosemide. Spironolactone treatment demonstrated significant attenuation of cardiac fibrosis and apoptosis in left ventricular tissue compared to furosemide. Further, spironolactone suppressed the expression of apoptosis-, NADPH oxidase 4 (NOX4)- and inducible nitric oxide synthase (iNOS)-associated proteins. Similarly, compared with MR patients receiving furosemide those prescribed spironolactone demonstrated a trend toward reduction in MR severity and showed improvement in left ventricular function. Collectively, MR-induced cardiovascular dysfunction, including fibrosis and apoptosis, was effectively attenuated by spironolactone treatment. Our findings suggest a potential therapeutic option for degenerative MR-induced HF.

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.

N-6-Methyladenosine in Vasoactive microRNAs during Hypoxia; A Novel Role for METTL4

N-6-methyladenosine (m6A) is the most prevalent post-transcriptional RNA modification in eukaryotic cells. The modification is reversible and can be dynamically regulated by writer and eraser enzymes. Alteration in the levels of these enzymes can lead to changes in mRNA stability, alternative splicing or microRNA processing, depending on the m6A-binding proteins. Dynamic regulation of mRNA m6A methylation after ischemia and hypoxia influences mRNA stability, alternative splicing and translation, contributing to heart failure. In this study, we studied vasoactive microRNA m6A methylation in fibroblasts and examined the effect of hypoxia on microRNAs methylation using m6A immunoprecipitation. Of the 19 microRNAs investigated, at least 16 contained m6A in both primary human fibroblasts and a human fibroblast cell line, suggesting vasoactive microRNAs are commonly m6A methylated in fibroblasts. More importantly, we found that mature microRNA m6A levels increased upon subjecting cells to hypoxia. By silencing different m6A writer and eraser enzymes followed by m6A immunoprecipitation, we identified METTL4, an snRNA m6A methyltransferase, to be predominantly responsible for the increase in m6A modification. Moreover, by using m6A-methylated microRNA mimics, we found that microRNA m6A directly affects downstream target mRNA repression efficacy. Our findings highlight the regulatory potential of the emerging field of microRNA modifications.

LncRNA PTPRG-AS1 Promotes the Metastasis of Hepatocellular Carcinoma by Enhancing YWHAG

Objectives

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. LncRNA PTPRG-AS1 (PTPRG-AS1) has been confirmed to function as a regulator in various cancers, whose function during HCC tumorigenesis is still not clear now. Thus, we aim to dig out the biological function and its mechanisms of PTPRG-AS1 in HCC.

Methods

PTPRG-AS1 relative expression in tissues and cells was detected and analyzed using real-time quantitative PCR (qRT-PCR). Subcellular distribution of PTPRG-AS1 was examined by FISH experiments. The effects of PTPRG-AS1 in the growth of HCC were studied by in vitro CCK-8 experiments, transwell invasion experiments, and in vivo xenograft tumor experiments. Dual-Luciferase reporter assay was performed to verify the interaction between PTPRG-AS1 and miR-199a-3p or miR-199a-3p and its target gene, YWHAG.

Results

PTPRG-AS1 was upregulated in HCC tissues compared with adjacent normal tissues. We identified PTPRG-AS1 mainly localized in the cytoplasm of HCC cells. Downregulation of PTPRG-AS1 suppressed HCC progression, while overexpression of PTPRG-AS1 showed the opposite effects. Furthermore, PTPRG-AS1 served as a miR-199a-3p sponge and positively regulated YWHAG expression. Besides, PTPRG-AS1 could promote HCC through miR-199a-3p/YWHAG axis.

Conclusions

Taken together, we demonstrated PTPRG-AS1 may serve as a ceRNA and reversely regulates the expression of miR-199a-3p, thus facilitating HCC tumorigenesis and metastasis, which is expected to provide new clues for the treatment of HCC.

Regulation of Key Antiplatelet Pathways by Bioactive Compounds with Minimal Bleeding Risk

Cardiovascular disease is strongly influenced by platelet activation. Platelet activation and thrombus formation at atherosclerotic plaque rupture sites is a dynamic process regulated by different signaling networks. Therefore, there are now focused efforts to search for novel bioactive compounds which target receptors and pathways in the platelet activation process while preserving normal hemostatic function. The antiplatelet activity of numerous fruits and vegetables and their multiple mechanisms of action have recently been highlighted. In this review, we review the antiplatelet actions of bioactive compounds via key pathways (protein disulfide isomerase, mitogen-activated protein kinases, mitochondrial function, cyclic adenosine monophosphate, Akt, and shear stress-induced platelet aggregation) with no effects on bleeding time. Therefore, targeting these pathways might lead to the development of effective antiplatelet strategies that do not increase the risk of bleeding.

Alternative platelet activation pathways and their role in neurodegenerative diseases

PURPOSE OF THE REVIEW

The study of platelets in the context of neurodegenerative diseases is intensifying, and increasing evidence suggests that platelets may play an important role in the pathogenesis of neurodegenerative disorders. Therefore, we aim to provide a comprehensive overview of the role of platelets and their diverse activation pathways in the development of these diseases.

RECENT FINDINGS

Platelets participate in synaptic plasticity, learning, memory, and platelets activated by exercise promote neuronal differentiation in several brain regions. Platelets also contribute to the immune response by modulating their surface protein profile and releasing pro- and anti-inflammatory mediators. In Alzheimer's disease, increased levels of platelet amyloid precursor protein raise the production of amyloid-beta peptides promoting platelet activation, triggering at the same time amyloid-beta fibrillation. In Parkinson's disease, increased platelet α-synuclein is associated with elevated ROS production and mitochondrial dysfunction.

SUMMARY

In this review, we revise different platelet activation pathways, those classically involved in hemostasis and wound healing, and alternative activation pathways recently described in the context of neurodegenerative diseases, especially in Alzheimer's disease.

Soy Isoflavones Inhibit Both GPIb-IX Signaling and αIIbβ3 Outside-In Signaling via 14-3-3ζ in Platelet

Soy diet is thought to help prevent cardiovascular diseases in humans. Isoflavone, which is abundant in soybean and other legumes, has been reported to possess antiplatelet activity and potential antithrombotic effect. Our study aims to elucidate the potential target of soy isoflavone in platelet. The anti-thrombosis formation effect of genistein and daidzein was evaluated in ex vivo perfusion chamber model under low (300 s-1) and high (1800 s-1) shear forces. The effect of genistein and daidzein on platelet aggregation and spreading was evaluated with platelets from both wildtype and GPIbα deficient mice. The interaction of these soy isoflavone with 14-3-3ζ was detected by surface plasmon resonance (SPR) and co-immunoprecipitation, and the effect of αIIbβ3-mediated outside-in signaling transduction was evaluated by western blot. We found both genistein and daidzein showed inhibitory effect on thrombosis formation in perfusion chamber, especially under high shear force (1800 s-1). These soy isoflavone interact with 14-3-3ζ and inhibited both GPIb-IX and αIIbβ3-mediated platelet aggregation, integrin-mediated platelet spreading and outside-in signaling transduction. Our findings indicate that 14-3-3ζ is a novel target of genistein and daidzein. 14-3-3ζ, an adaptor protein that regulates both GPIb-IX and αIIbβ3-mediated platelet activation is involved in soy isoflavone mediated platelet inhibition.

Glutamine metabolism: from proliferating cells to cardiomyocytes

Glutamine is a major energy source for rapidly dividing cells, such as hematopoietic stem cells and cancer cells. Reliance on glutamine is therefore regarded as a metabolic hallmark of proliferating cells. Moreover, reprogramming glutamine metabolism by various factors, including tissue type, microenvironment, pro-oncogenes, and tumor suppressor genes, can facilitate stem cell fate decisions, tumor recurrence, and drug resistance. However, the significance of glutamine metabolism in cardiomyocytes, an end-differentiated cell type, is not fully understood. Existing evidence suggests important roles of glutamine metabolism in the development of cardiovascular diseases. In this review, we have focused on glutaminolysis and its regulatory network in proliferating cells. We have summarized current findings about the role of glutamine utilization in cardiomyocytes and have discussed possibilities of targeting glutamine metabolism for the treatment of cardiovascular diseases.

Investigating the relationship between the severity of coronary artery disease and inflammatory factors of MHR, PHR, NHR, and IL-25

Background: Coronary artery disease (CAD), as a most common cause of death, is mainly caused by atherosclerosis. Due to the role of inflammation in the process of atherosclerosis, in the present study, the relationship between the severity of coronary artery disease and inflammatory factors of monocyte to HDL-C ratio (MHR), platelet-to-HDL-C ratio (PHR), neutrophil to HDL-C ratio (NHR), and IL-25 was investigated.

Methods: In this cross-sectional study, 64 patients with diagnosis of coronary artery disease who were undergoing angiography in Farshchian heart center in Hamadan were studied. For each patient, the count of monocytes, neutrophils, platelet, and HDL-C, and IL-25 were measured from their blood and serum samples. Also, demographic information, such as age, gender, diabetes, smoking, and history of hypertension, was collected using a checklist. Data were described using frequency, percent, mean, and standard deviation. Statistical analysis was performed using independent t test, Mann-Whitney, Wilcoxon, and Spearman rank correlation tests, and multiple linear regression by SPSS version 25.0 SPSS Inc). P <.05 was considered as significant.

Results: The results of this study showed that IL-25 and MHR index has a significant correlation with coronary artery disease and Gensini score (P ˂.001). The PHR index was associated with coronary artery disease. Also, qualitative variables, such as history of hypertension, history of smoking, and gender, have a significant association with the severity of coronary artery disease (P <.05).

Conclusion: Among the inflammatory markers examined, IL-25 and MHR are stronger markers for assessing the severity of coronary artery disease. Simple and available IL-25 and MHR measurements may be able to, along with common risk factors and lipid profiles, predict the amount of vascular occlusion in treatment centers as an alternative of angiography as well as screening high risk patients prone to cardiovascular disease.

Expression Levels of MicroRNA-146b and Anti-Cardiac Troponin I in Serum of Children with Viral Myocarditis and Their Clinical Significance

Background

To investigate the expression levels of microRNA-146b (miR-146b) and cardiac troponin I (anti-cTnI) in serum of children with viral myocarditis and their clinical significance.

Methods

Forty-eight children with viral myocarditis (patient group) and 40 healthy physical examinees (healthy group), who were diagnosed in Jinan City People's Hospital Affiliated to Shandong First Medical University, China from Feb 2018 to May 2019, were enrolled as study subjects. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the level of miR-146b in serum of children. ELISA was used to detect the expression of anti-cTnI in serum of children. Pearson was used to analyze the correlation between the level of miR-146b and the level of anti-cTnI, and the factors affecting the prognosis.

Results

The levels of miR-146b and anti-cTnI in serum of children in patient group were statistically significantly higher than those of healthy group (P<0.01). The AUC of miR-146b was 0.741, (95% CI: 0.638-0.843), the specificity was 62.50%, the sensitivity was 82.50%, and the AUC of anti-cTnI was 0.720 (95% CI: 0.608-0.832), the specificity was 64.58% and the sensitivity was 92.50%. The level of miR-146b was positively correlated with the level of anti-cTnI (r=0.601, P<0.05). CK-MB, LVEF, miR-146b and anti-cTnI expression were independent risk factors affecting the prognosis.

Conclusion

The levels of miR-146b and anti-cTnI increased in serum of patients with viral myocarditis. They were related to the degree of myocardial injury, which indicated that miR-146b and anti-cTnI might be involved in the pathological process of viral myocarditis.

Inflammation as a risk factor for stroke in atrial fibrillation: data from a microarray data analysis

Objective

Stroke is a severe complication of atrial fibrillation (AF). We aimed to discover key genes and microRNAs related to stroke risk in patients with AF using bioinformatics analysis.

Methods

GSE66724 microarray data, including peripheral blood samples from eight patients with AF and stroke and eight patients with AF without stroke, were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between AF patients with and without stroke were identified using the GEO2R online tool. Functional enrichment analysis was performed using the DAVID database. A protein–protein interaction (PPI) network was obtained using the STRING database. MicroRNAs (miRs) targeting these DEGs were obtained from the miRNet database. A miR–DEG network was constructed using Cytoscape software.

Results

We identified 165 DEGs (141 upregulated and 24 downregulated). Enrichment analysis showed enrichment of certain inflammatory processes. The miR–DEG network revealed key genes, including MEF2A, CAND1, PELI1, and PDCD4, and microRNAs, including miR-1, miR-1-3p, miR-21, miR-21-5p, miR-192, miR-192-5p, miR-155, and miR-155-5p.

Conclusion

Dysregulation of certain genes and microRNAs involved in inflammation may be associated with a higher risk of stroke in patients with AF. Evaluating these biomarkers could improve prediction, prevention, and treatment of stroke in patients with AF.

MicroRNAs in Platelets: Should I Stay or Should I Go?

In this chapter, we discuss different topics always using the microRNA as the guiding thread of the review. MicroRNAs, member of small noncoding RNAs family, are an important element involved in gene expression. We cover different issues such as their importance in the differentiation and maturation of megakaryocytes (megakaryopoiesis), as well as the role in platelets formation (thrombopoiesis) focusing on the described relationship between miRNA and critical myeloid lineage transcription factors such as RUNX1, chemokines receptors as CRCX4, or central hormones in platelet homeostasis like TPO, as well as its receptor (MPL) and the TPO signal transduction pathway, that is JAK/STAT. In addition to platelet biogenesis, we review the microRNA participation in platelets physiology and function. This review also introduces the use of miRNAs as biomarkers of platelet function since the detection of pathogenic situations or response to therapy using these noncoding RNAs is getting increasing interest in disease management. Finally, this chapter describes the participation of platelets in cellular interplay, since extracellular vesicles have been demonstrated to have the ability to deliver microRNAs to others cells, modulating their function through intercellular communication, redefining the extracellular vesicles from the so-called “platelet dust” to become mediators of intercellular communication.

MiR-223 levels predicting perioperative bleeding in off-pump coronary artery bypass grafting

Background

To investigate the predictive value of platelet-related microRNAs (miRNAs) for bleeding during and after off-pump coronary artery bypass grafting (OPCABG) and the influence of dual antiplatelet therapy (DAPT) on miRNAs.

Methods

This prospective study included 59 patients scheduled for OPCABG. The plasma miR-126 and miR-223 levels were measured and platelet aggregation was determined by thromboelastography during DAPT. The plasma miRNA levels were compared between patients treated with ticagrelor or clopidogrel. Multivariable logistic regression analysis was performed to determine the independent risk factors for bleeding during and after surgery. Active bleeding was defined as a blood loss >1.5 mL/kg/h for 6 consecutive hours within the first 24 hours or in case of reoperation during the first 12 postoperative hours. Severe perioperative bleeding was defined using the universal definition of perioperative bleeding in adult cardiac surgery.

Results

Higher circulating miR-223 levels [odds ratio (OR) =1.348, 95% confidence interval (CI): 1.001–1.814, P=0.047] and lower body mass index (OR =0.648, 95% CI: 0.428–0.980, P=0.040) were independent predictors for severe perioperative bleeding in OPCABG. Ticagrelor treatment led to significant increases in circulating miR-223 levels compared with clopidogrel treatment.

Conclusions

The plasma miR-223 levels served as a predictor for bleeding during and after OPCABG. Circulating miR-223 levels were significantly elevated with ticagrelor treatment compared with clopidogrel treatment. MiR-223 may be a novel biomarker for bleeding in cardiac surgery and can help explain the different efficacies of ticagrelor and clopidogrel.

Knockout of miR-21-5p alleviates cartilage matrix degradation by targeting Gdf5 in temporomandibular joint osteoarthritis

AIMS

The study aimed to determine whether the microRNA miR21-5p (MiR21) mediates temporomandibular joint osteoarthritis (TMJ-OA) by targeting growth differentiation factor 5 (Gdf5).

METHODS

TMJ-OA was induced in MiR21 knockout (KO) mice and wild-type (WT) mice by a unilateral anterior crossbite (UAC) procedure. Mouse tissues exhibited histopathological changes, as assessed by: Safranin O, toluidine blue, and immunohistochemistry staining; western blotting (WB); and quantitative real-time polymerase chain reaction (RT-qPCR). Mouse condylar chondrocytes were transfected with a series of MiR21 mimic, MiR21 inhibitor, Gdf5 siRNA (si-GDF5), and flag-GDF5 constructs. The effects of MiR-21 and Gdf5 on the expression of OA related molecules were evaluated by immunofluorescence, alcian blue staining, WB, and RT-qPCR.

RESULTS

UAC altered the histological structure and extracellular matrix content of cartilage in the temporomandibular joint (TMJ), and KO of MiR21 alleviated this effect (p < 0.05). Upregulation of MiR21 influenced the expression of TMJ-OA related molecules in mandibular condylar chondrocytes via targeting Gdf5 (p < 0.05). Gdf5 overexpression significantly decreased matrix metalloproteinase 13 (MMP13) expression (p < 0.05) and reversed the effects of MiR21 (p < 0.05).

CONCLUSION

MiR21, which acts as a critical regulator of Gdf5 in chondrocytes, regulates TMJ-OA related molecules and is involved in cartilage matrix degradation, contributing to the progression of TMJ-OA. Cite this article: Bone Joint Res 2020;9(10):689-700.

VCP Machinery Mediates Autophagic Degradation of Empty Argonaute

The Argonaute subfamily of proteins (AGO) loads microRNAs (miRNAs) to form the effector complex that mediates target gene silencing. Empty AGO, but not miRNA-loaded AGO, is selectively degraded across species. We have reported that the degradation of empty AGO is part of a quality control pathway that eliminates dysfunctional AGO. However, how empty AGO is degraded remains unclear. Here we show that the empty state of Drosophila Ago1 is degraded by autophagy. Comprehensive LC-MS/MS analyses, together with manipulation of the Ago1 ubiquitination level, revealed that VCP, which mediates selective autophagy, recognizes empty Ago1 via the Ufd1-Npl4 heterodimer. Depletion of VCP-Ufd1-Npl4 machinery impairs degradation of empty Ago1 and miRNA-mediated target gene silencing. Our findings reveal a direct link between empty AGO degradation and selective autophagy that ensures efficient miRNA function.

Antiplatelet Activity of Tussilagone via Inhibition of the GPVI Downstream Signaling Pathway in Platelets

Tussilagone is a sesquiterpenoid extracted from Tussilago farfara and is used as an oriental medicine for asthma and bronchitis. Although previous studies have shown that tussilagone has an inhibitory effect on platelet aggregation, no studies have been performed to investigate its precise effect on platelets, and the underlying mechanism remains unclear. In the present study, we showed that tussilagone inhibited platelet aggregation induced by collagen, thrombin and ADP, as well as platelet release induced by collagen and thrombin, in mice. Tussilagone decreased P-selectin expression and αIIbβ3 activation (JON/A binding) in activated platelets, which indicated that tussilagone inhibited platelet activation. Moreover, tussilagone suppressed platelet spreading on fibrinogen and clot retraction. The levels of phosphorylated Syk, PLCγ2, Akt, GSK3β, and MAPK (ERK1/2 and P38) and molecules associated with GPVI downstream signaling were downregulated in the presence of tussilagone. In addition, tussilagone prolonged the occlusion time in a mouse model of FeCl₃-induced carotid artery thrombosis and had no effect on mouse tail bleeding time. These results indicate that tussilagone inhibits platelet function in vitro and in vivo and that the underlying mechanism involves the Syk/PLCγ2-PKC/MAPK and PI3K-Akt-GSK3β signaling pathways downstream of GPVI. This research suggests that tussilagone is a potential candidate antiplatelet drug for the prevention of thrombosis.

Platelets in Healthy and Disease States: From Biomarkers Discovery to Drug Targets Identification by Proteomics

Platelets are a heterogeneous small anucleate blood cell population with a central role both in physiological haemostasis and in pathological states, spanning from thrombosis to inflammation, and cancer. Recent advances in proteomic studies provided additional important information concerning the platelet biology and the response of platelets to several pathophysiological pathways. Platelets circulate systemically and can be easily isolated from human samples, making proteomic application very interesting for characterizing the complexity of platelet functions in health and disease as well as for identifying and quantifying potential platelet proteins as biomarkers and novel antiplatelet therapeutic targets. To date, the highly dynamic protein content of platelets has been studied in resting and activated platelets, and several subproteomes have been characterized including platelet-derived microparticles, platelet granules, platelet releasates, platelet membrane proteins, and specific platelet post-translational modifications. In this review, a critical overview is provided on principal platelet proteomic studies focused on platelet biology from signaling to granules content, platelet proteome changes in several diseases, and the impact of drugs on platelet functions. Moreover, recent advances in quantitative platelet proteomics are discussed, emphasizing the importance of targeted quantification methods for more precise, robust and accurate quantification of selected proteins, which might be used as biomarkers for disease diagnosis, prognosis and therapy, and their strong clinical impact in the near future.

Exploration of the Two-Way Adjustment Mechanism of Rhei Radix et Rhizoma for Cardiovascular Diseases

AIM AND OBJECTIVE

Myocardial infarction, cerebral infarction, and other diseases caused by vascular obstruction have always jeopardized human life and health. Several reports indicate that Rhei Radix et Rhizoma has a good clinical effect in the prevention and treatment of cardiovascular diseases. Owing to the complexity of herbal medicine, the pharmacodynamic mechanism of Rhei Radix et Rhizoma is still unclear. The objectives of this study were to explore the two-way adjustment mechanism of Rhei Radix et Rhizoma and provide a new solution for the prevention and treatment of cardiovascular disease.

MATERIALS AND METHODS

This study used data mining, reverse pharmacophore matching, network construction, GO and KEGG Analysis, and molecular docking to investigate the two-way adjustment mechanism of Rhei Radix et Rhizoma. The methods used were based on systems pharmacology and big data analysis technology.

RESULTS

The results suggest that Rhei Radix et Rhizoma uses a two-way adjustment of activating blood circulation, as well as blood coagulation in the prevention and treatment of cardiovascular diseases. The components involved in activating blood circulation are mainly anthraquinone components. The corresponding targets are NOS2, NOS3, CALM1, and the corresponding pathways are calcium signaling pathway, VEGF signaling pathway, platelet activation, and the PI3K-Akt signaling pathway. For blood coagulation, the components are mainly tannin components; the corresponding targets are F2, F10, ELANE, and the corresponding pathways are the neuroactive ligand-receptor interaction, complement and coagulation cascades.

CONCLUSION

This study indicated that Rhei Radix et Rhizoma exerts the two-way adjustment of activating blood circulation and blood coagulation in the prevention and treatment of cardiovascular diseases. It can make up for the side effects of the existing blood circulation drugs for cardiovascular disease, only activating blood circulation, and the uncontrollable large-area bleeding due to the long-term use of the drugs. This study provides a material basis for the development of new blood-activating drugs based on natural medicine.

MicroRNA-29a-3p regulates abdominal aortic aneurysm development and progression via direct interaction with PTEN

Various research studies have been conducted in deducing the role of microRNAs (miRNAs) in the pathogenesis and physiological processes of various systematic diseases. This study aims at demonstration of the important role played by miR-29a-3p, through association with phosphatase and tensin homolog (PTEN), in the regulation of abdominal aortic aneurysm development and progression. Quantitative real-time polymerase chain reaction (RT-qPCR) examined miRNA-19a-3p and PMEPA1 expression in multiplied vascular smooth muscle cells (VSMCs). Cell transfection upregulated or downregulated the genes and cell counting kit-8 assay determined cellular viability. RT-qPCR detected cellular proliferation and cell death using the cell proliferation and apoptosis biomarkers Ki87 and proliferating cell nuclear antigen, caspase-8 and caspase-3, respectively. Furthermore, luciferase assay analyzed the luciferase activity and western blot analysis determined miRNA-19a-3p and PMEPA1 protein expression in proliferation and apoptosis biomarkers. TargetScan 4.2 online software (www.targetscan.org) was used to perform the bioinformatics analysis so as to forecast the putative targets of miR-29a-3p and PTEN. The results inferred that there was an increased expression of miRNA-29a-3p found in AAA-mimic cells with increased cellular viability and significant pathological apoptosis. Further, when the expression of miRNA-29a-3p was downregulated, it reduced the cell viability of AAA cells. On the basis of the gene interplays, it can be understood that the PTEN was directly targeted by miRNA-29a-3p so as to regulate the AAA progression. Thus, PTEN was found to strengthen the proliferation effect of miRNA-29a-3p in AAA cells. The current study thus shed more insights about the molecular mechanistic roles of miRNA-29a-3p and PTEN, opening doors for novel therapeutic approach to AAA.

Pharmacologic dissection of the overlapping impact of heat shock protein family members on platelet function

BACKGROUND

Platelets play a pivotal role in hemostasis, wound healing, and inflammation, and are thus implicated in a variety of diseases, including cancer. Platelet function is associated with release of granule content, cellular shape change, and upregulation of receptors that promote establishment of a thrombus and maintenance of hemostasis.

OBJECTIVES

The role of heat shock proteins (Hsps) in modulating platelet function has been studied for a number of years, but comparative roles of individual Hsps have not been thoroughly examined.

METHODS

We utilized a panel of specific inhibitors of Hsp40, Hsp70, Hsp90, and Grp94 (the endoplasmic reticulum homolog of Hsp90) to assess their impact on several aspects of platelet function.

RESULTS

Inhibition of each of the aforementioned Hsps reduced alpha granule release. In contrast, there was some selectivity in impacts on dense granule release. Thromboxane synthesis was impaired after exposure to inhibitors of Hsp40, Hsp90, and Grp94, but not after inhibition of Hsp70. Both expression of active glycoprotein IIb/IIIa (GPIIb/IIIa) and fibrinogen-induced platelet shape change were diminished by our inhibitors. In contrast, aggregation was selectively abrogated after inhibition of Hsp40 or Hsp90. Lastly, activated platelet-cancer cell interactions were reduced by inhibition of both Hsp70 and Grp94.

CONCLUSIONS

These data suggest the importance of Hsp networks in regulating platelet activity.

Platelet factor 4 and β-thromboglobulin mRNAs in circulating microparticles of trauma patients as diagnostic markers for deep vein thrombosis

Deep vein thrombosis (DVT) is a common complication after trauma. The development of markers to predict DVT in trauma patients is needed, and circulating microparticles (MPs) and their contents are possible candidates. In this study, we aimed to identify platelet factor 4 (PF4) and β-thromboglobulin (β-TG) mRNAs in circulating MPs as potential markers for DVT diagnosis in trauma patients. Fifteen trauma patients diagnosed with DVT and fifteen matched patients without DVT were included in this study. Fifteen healthy volunteers also were included as controls. Circulating MPs were obtained from the plasma of all study subjects. Annexin V+ MPs and platelet-derived MPs (PMPs) were quantified using flow cytometry. PF4 and β-TG mRNAs in MPs were determined by qPCR, and the common logarithm of relative quantitation (RQ) was calculated using the comparative Ct method. Receiver-operating characteristic (ROC) curves were performed to analyze the diagnostic value of PF4 and β-TG mRNAs. No significant differences were found in Annexin V+ MPs and PMPs levels between trauma patients with and without DVT. However, both PF4 and β-TG mRNAs in MPs from the DVT group were significantly higher than the non-DVT group and healthy controls (P = 0.014 for PF4, P = 0.010 for β-TG). The ROC curve analysis showed that both the PF4 mRNA (area-under curve (AUC) 0.756, P = 0.017) and the β-TG mRNA (AUC 0.751, P = 0.019) had a positive predictive value for DVT. This finding indicates that the PF4 and β-TG mRNAs in MPs may be used as potential biomarkers for DVT diagnosis in trauma patients.

Bayesian network analysis of plasma microRNA sequencing data in patients with venous thrombosis

MicroRNAs (miRNAs) are small regulatory RNAs participating to several biological processes and known to be involved in various pathologies. Measurable in body fluids, miRNAs have been proposed to serve as efficient biomarkers for diseases and/or associated traits. Here, we performed a next-generation-sequencing based profiling of plasma miRNAs in 344 patients with venous thrombosis (VT) and assessed the association of plasma miRNA levels with several haemostatic traits and the risk of VT recurrence. Among the most significant findings, we detected an association between hsa-miR-199b-3p and haematocrit levels (P = 0.0016), these two markers having both been independently reported to associate with VT risk. We also observed suggestive evidence for association of hsa-miR-370-3p (P = 0.019), hsa-miR-27b-3p (P = 0.016) and hsa-miR-222-3p (P = 0.049) with VT recurrence, the observations at the latter two miRNAs confirming the recent findings of Wang et al. Besides, by conducting Genome-Wide Association Studies on miRNA levels and meta-analyzing our results with some publicly available, we identified 21 new associations of single nucleotide polymorphisms with plasma miRNA levels at the statistical significance threshold of P < 5 × 10-8, some of these associations pertaining to thrombosis associated mechanisms. In conclusion, this study provides novel data about the impact of miRNAs' variability in haemostasis and new arguments supporting the association of few miRNAs with the risk of recurrence in patients with venous thrombosis.

Virtual Screening of the Multi-pathway and Multi-gene Regulatory Molecular Mechanism of Dachengqi Decoction in the Treatment of Stroke Based on Network Pharmacology

BACKGROUND

Stroke is ranked second among diseases that cause mortality worldwide. Owing to its complicated pathogenesis, no satisfactory treatment strategies for stroke are available. Dachengqi decoction (DCQD), a traditional Chinese herbal medicine, has been widely used in China for a long time, as it has a good effect on stroke. However, the molecular mechanism underlying this effect of DCQD is unclear.

OBJECTIVE

In the present study, we aimed to reveal and explore the multi-pathway and multi-gene regulatory molecular mechanism of Dachengqi decoction in the treatment of stroke.

METHODS

In this study, a network pharmacology method, in combination with oral bioavailability prediction and drug-likeness evaluation, was employed to predict the active ingredients of DCQD. The target genes of the active components and the traced pathways related to these target genes were predicted. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using clusterProfiler software package on the R platform and ClueGo+CluePedia plug-ins. Finally, the key DCQD targets were verified using the Gene Expression Omnibus (GEO) dataset.

RESULTS AND DISCUSSION

According to the ADME model, 52 active components were screened from 296 active components of DCQD. After prediction and screening, 215 stroke-related targets were obtained and analyzed via GO and KEGG analyses. GO analysis showed that DCQD targets were mainly involved in the regulation of oxidative stress, lipid metabolism, inflammation, and other biological processes. KEGG pathway analysis further revealed pathways involved in stroke, such as arachidonic acid metabolic, HIF-1 signaling pathway, estrogen signaling pathway, MAPK signaling pathway, PI3K-Akt signaling pathway, platelet activation pathway, VEGF signaling pathway, and cAMP signaling pathway. Network analysis revealed that DCQD might be involved in the regulation of lipid metabolism, blood pressure, inflammation, angiogenesis, neuroprotection, platelet aggregation, apoptosis, and oxidation in stroke treatment. GEO dataset analysis showed that DCQD's therapeutic effects might be exerted via the bidirectional regulation principle.

CONCLUSION

Based on the methods of network pharmacology and GEO analysis, it was found that, during stroke treatment, DCQD regulates and controls multiple genes and multiple pathways in a synergistic manner, providing a new strategy for stroke treatment.

Fully automated platelet isolation on a centrifugal microfluidic device for molecular diagnostics

Platelets play crucial roles in hemostasis and immunity. Over the last decades, clinical evidence has revealed the significance of platelets as complementary biomarkers for the detection and treatment of various diseases, including cancer. Due to a lack of well standardized convenient isolation methods for platelets, pre-analytical factors such as complex handling procedures negatively impact the quality of the platelet samples, including overactivation, low purity, and poor reproducibility. This may lead to biased interpretation of various downstream analyses, such as proteomic and genomic analyses. Herein, we describe a fully automated lab-on-a-disc-based method of platelet isolation from a small volume of blood (<1 mL). This method provides higher yields (>4 folds) and purity (>99%) and lower platelet activation than the conventional method. Moreover, it was also superior in the detection of platelet-related RNAs CD41, PF4, and P2Y12 due to lower contamination with white blood cells.

Platelet biology and functions: new concepts and clinical perspectives

Platelets - blood cells continuously produced from megakaryocytes mainly in the bone marrow - are implicated not only in haemostasis and arterial thrombosis, but also in other physiological and pathophysiological processes. This Review describes current evidence for the heterogeneity in platelet structure, age, and activation properties, with consequences for a diversity of platelet functions. Signalling processes of platelet populations involved in thrombus formation with ongoing coagulation are well understood. Genetic approaches have provided information on multiple genes related to normal haemostasis, such as those encoding receptors and signalling or secretory proteins, that determine platelet count and/or responsiveness. As highly responsive and secretory cells, platelets can alter the environment through the release of growth factors, chemokines, coagulant factors, RNA species, and extracellular vesicles. Conversely, platelets will also adapt to their environment. In disease states, platelets can be positively primed to reach a pre-activated condition. At the inflamed vessel wall, platelets interact with leukocytes and the coagulation system, interactions mediating thromboinflammation. With current antiplatelet therapies invariably causing bleeding as an undesired adverse effect, novel therapies can be more beneficial if directed against specific platelet responses, populations, interactions, or priming conditions. On the basis of these novel concepts and processes, we discuss several initiatives to target platelets therapeutically.

Hypertension Associated With Hyperlipidemia Induced Different MicroRNA Expression Profiles in Plasma, Platelets, and Platelet-Derived Microvesicles; Effects of Endothelial Progenitor Cell Therapy

Aim: The aim of this study was to analyze the expressed profiles of miRNAs in plasma, platelets, and platelet-derived microvesicles (PMVs) obtained from experimental induced atherosclerosis animal model and to investigate the effect of EPC transplantation on these profiles. Methods: Seventeen selected circulating miRNAs (miR-19a,-21,-126,-146a,-223,-26b,-92a,-222,-210,-221,-143,-10a,-145,-155,-34a,-204, and miR-214) were individually analyzed in plasma, platelets, and PMVs isolated from peripheral blood of hypertensive-hyperlipidemic hamsters treated or not with endothelial progenitor cells (EPCs), and of healthy hamsters taken as control group. Results: Comparative with control group, in hypertension associated with hyperlipidemia the investigated miRNA expression profiles were different: (i) in plasma, the levels of all investigated miRNAs were significantly increased, the highest enhances being noticed for miR-21,-146a,-221,-143,-34a, and miR-204; (ii) in platelets, the expressions of almost all miRNAs were significantly elevated, remarkable for miR-126,-146a,-223,-222, and miR-214, while levels of miR-143, miR-10a, and miR-145 were significantly reduced; (iii) in PMVs, numerous miRNAs were found to have significantly increased levels, especially miR-222,-221,-210, and miR-34a, whereas expressions of various miRNAs as miR-223,-214,-146a,-143,-10a, and miR-145 were significantly decreased. The treatment with EPCs had the following reverse effects: (i) in plasma, significantly reduced the expression of miR-26b,-143,-34a,-204, and miR-214; (ii) in platelets, significantly decreased the levels of almost investigated miRNAs, with remarkably diminishing for miR-126 and miR-221; and (iii) in PMVs, significantly lowered the expression of some miRNAs, with considerably reductions for miR-222,-221,-210, and miR-19a, while the level of miR-214 was found elevated. Conclusions: The present study revealed that miRNAs have differential expression profiles in plasma, platelets, and PMVs under hypertension associated with hyperlipidemia conditions. The different miRNA profile in PMVs compared with platelets indicated an active mechanism of selective packing of miRNAs into PMVs from maternal cells; various miRNAs such as miR-19a,-21,-126,-26b,-92a,-155,-204,-210,-221,-222, and-34a delivered by PMVs may contribute to enrichment of circulating plasma miRNA expression. In addition, our study showed that the EPC-based therapy can regulate the expressions of investigated miRNAs into the three sources. These results provide novel information that could help in finding potential targets for the development of new therapeutic strategies in the cardiovascular disease.

The role of endothelial miRNAs in myocardial biology and disease

The myocardium is a highly structured pluricellular tissue which is governed by an intricate network of intercellular communication. Endothelial cells are the most abundant cell type in the myocardium and exert crucial roles in both healthy myocardium and during myocardial disease. In the last decade, microRNAs have emerged as new actors in the regulation of cellular function in almost every cell type. Here, we review recent evidence on the regulatory function of different microRNAs expressed in endothelial cells, also called endothelial microRNAs, in healthy and diseased myocardium. Endothelial microRNA emerged as modulators of angiogenesis in the myocardium, they are implicated in the paracrine role of endothelial cells in regulating cardiac contractility and homeostasis, and interfere in the crosstalk between endothelial cells and cardiomyocytes.

Prediction of binding characteristics between von Willebrand factor and platelet glycoprotein Ibα with various mutations by molecular dynamic simulation

INTRODUCTION

Binding of platelet glycoprotein (GP)Ibα with von-Willebrand factor (VWF) exclusively mediates the initial platelet adhesion to injured vessel wall. To understand the mechanism of biomedical functions, we calculated the dynamic fluctuating three-dimensional (3D) structures and dissociation energy for GPIbα with various single amino-acid substitution at G233, which location is known to cause significant changes in platelet adhesive characteristics.

MATERIAL AND METHODS

Molecular dynamics (MD) simulation was utilized to calculate 3D structures and Potential of Mean Force (PMF) for wild-type VWF bound with wild-type, G233A (equal function), G233V (gain of function), and G233D (loss of function) GPIbα. Simulation was done on water-soluble condition with time-step of 2 × 10^-15 s using NAnoscale Molecular Dynamics (NAMD) with Chemistry at HARvard Molecular Mechanics (CHARMM) force field. Initial structure for each mutant was obtained by inducing single amino-acid substitution to the stable water-soluble binding structure of wild-type.

RESULTS

The most stable structures of wild-type VWF bound to GPIbα in wild-type or any mutant did not differ. However, bond dissociation energy defined as difference of PMF between most stable structure and the structure at 65 Å mass center distances in G233D was 4.32 kcal/mol (19.5%) lower than that of wild-type. Approximately, 2.07 kcal/mol energy was required to dissociate VWF from GPIbα with G233V at mass center distance from 48 to 52 Å, which may explain the apparent "gain of function" in G233V.

CONCLUSION

The mechanism of substantially different biochemical characteristics of GPIbα with mutations in G233 location was predicted from physical movement of atoms constructing these proteins.

Advances in Platelet Subpopulation Research

Although lacking a nucleus, platelets are increasingly recognized not only for their complexity, but also for their diversity. Some 50 years ago platelet subpopulations were characterized by size and density, and these characteristics were thought to reflect platelet aging. Since, our knowledge of platelet heterogeneity has grown to recognize that differences in platelet biochemistry and function exist. This includes the identification of vanguard and follower platelets, platelets with differing procoagulant ability including "COAT-platelets" which enhance procoagulant protein retention on their surface, and most recently, the identification of platelet subpopulations with a differential ability to generate and respond to nitric oxide. Hence, in this mini-review, we summarize the current knowledge of platelet subpopulation diversity focusing on their physical, biochemical, and functional heterogeneity. In addition, we review how platelet subpopulations may change between health and disease and how differences among platelets may influence response to anti-platelet therapy. Finally, we look forward and discuss some of the future directions and challenges for this growing field of platelet research.

Efferocytosis and Atherosclerosis: Regulation of Phagocyte Function by MicroRNAs

There is evidence of the critical role of efferocytosis, the clearance of apoptotic cells (ACs) by phagocytes, in vascular cell homeostasis and protection against atherosclerosis. Specific microRNAs (miRs) can regulate atherogenesis by controlling the accumulation of professional phagocytes (e.g., macrophages) and nonprofessional phagocytes (i.e., neighboring tissue cells with the ability to acquire a macrophage-like phenotype) within the arterial wall, the differentiation of phagocytes into foam cells, the efferocytosis of apoptotic foam cells by phagocytes, and the phagocyte-mediated inflammatory response. A better understanding of the mechanisms involved in miR-regulated phagocyte function might lead to novel therapeutic antiatherosclerotic strategies. In this review, we try to shed light on the relationship between miRs and cellular players in the process of efferocytosis in the context of atherosclerotic plaque and their potential as molecular targets for novel antiatherosclerotic therapies.

The non-haemostatic role of platelets in systemic lupus erythematosus

Dysregulation of lymphocyte function, accumulation of autoantibodies and defective clearance of circulating immune complexes and apoptotic cells are hallmarks of systemic lupus erythematosus (SLE). Moreover, it is now evident that an intricate interplay between the adaptive and innate immune systems contributes to the pathogenesis of SLE, ultimately resulting in chronic inflammation and organ damage. Platelets circulate in the blood and are chiefly recognized for their role in the prevention of bleeding and promotion of haemostasis; however, accumulating evidence points to a role for platelets in both adaptive and innate immunity. Through a broad repertoire of receptors, platelets respond promptly to immune complexes, complement and damage-associated molecular patterns, and represent a major reservoir of immunomodulatory molecules in the circulation. Furthermore, evidence suggests that platelets are activated in patients with SLE, and that they could contribute to the circulatory autoantigenic load through the release of microparticles and mitochondrial antigens. Herein, we highlight how platelets contribute to the immune response and review evidence implicating platelets in the pathogenesis of SLE.

Hypoxia drives cardiac miRNAs and inflammation in the right and left ventricle

Alveolar and myocardial hypoxia may be causes or sequelae of pulmonary hypertension (PH) and heart failure. We hypothesized that hypoxia initiates specific epigenetic and transcriptional, pro-inflammatory programs in the right ventricle (RV) and left ventricle (LV). We performed an expression screen of 750 miRNAs by qPCR arrays in the murine RV and LV in normoxia (Nx) and hypoxia (Hx; 10% O₂ for 18 h, 48 h, and 5d). Additional validation included single qPCR analysis of miRNA and pro-inflammatory transcripts in murine and human RV/LV, and neonatal rat cardiomyocytes (NRCMs). Differential qPCR-analysis (Hx vs. Nx in RV, Hx vs. Nx in LV, and RV vs. LV in Hx) identified nine hypoxia-regulated miRNAs: let-7e-5p, miR-29c-3p, miR-127-3p, miR-130a-3p, miR-146b-5p, miR-197-3p, miR-214-3p, miR-223-3p, and miR-451. Hypoxia downregulated miR-146b in the RV (p < 0.01) and, less so, in the LV (trend; p = 0.28). In silico alignment showed significant binding affinity of miR-146b-5p sequence with the 3'UTR of TRAF6 known to be upstream of pro-inflammatory NF-kB. Consistently, hypoxia induced TRAF6, IL-6, CCL2(MCP-1) in the mouse RV and LV. Incubating neonatal rat cardiomyocytes with pre-miR-146b led to a downregulation of TRAF6, IL-6, and CCL2(MCP-1). TRAF6 mRNA expression was also increased by 3-fold in the RV and LV of end-stage idiopathic pulmonary arterial hypertension (PAH) patients vs. non-PAH controls. We identified hypoxia-regulated, ventricle-specific miRNA expression profiles in the adult mouse heart in vivo. Hypoxia suppresses miR-146b, thus de-repressing TRAF6, and inducing pro-inflammatory IL-6 and CCL2(MCP-1). This novel hypoxia-induced miR-146b-TRAF6-IL-6/CCL2(MCP-1) axis likely drives cardiac fibrosis and dysfunction, and may lead to heart failure. KEY MESSAGES: Chouvarine P, Legchenko E, Geldner J, Riehle C, Hansmann G. Hypoxia drives cardiac miRNAs and inflammation in the right and left ventricle. • Hypoxia drives ventricle-specific miRNA profiles, regulating cardiac inflammation. • miR-146b-5p downregulates TRAF6, known to act upstream of pro-inflammatory NF-κB. • Hypoxia downregulates miR-146b and induces TRAF6, IL-6, CCL2 (MCP-1) in the murine RV and LV. • The inhibitory regulatory effects of miR-146b are confirmed in primary rat cardiomyocytes (pre-miR, anti-miR) and human explant heart tissue (endstage pulmonary arterial hypertension). • A novel miR-146b-TRAF6-IL-6/CCL2(MCP-1) axis likely drives cardiac inflammation, fibrosis and ventricular dysfunction.

Systematic review regulatory principles of non-coding RNAs in cardiovascular diseases

Cardiovascular diseases (CVDs) continue to be a major cause of morbidity and mortality, and non-coding RNAs (ncRNAs) play critical roles in CVDs. With the recent emergence of high-throughput technologies, including small RNA sequencing, investigations of CVDs have been transformed from candidate-based studies into genome-wide undertakings, and a number of ncRNAs in CVDs were discovered in various studies. A comprehensive review of these ncRNAs would be highly valuable for researchers to get a complete picture of the ncRNAs in CVD. To address these knowledge gaps and clinical needs, in this review, we first discussed dysregulated ncRNAs and their critical roles in cardiovascular development and related diseases. Moreover, we reviewed >28 561 published papers and documented the ncRNA-CVD association benchmarking data sets to summarize the principles of ncRNA regulation in CVDs. This data set included 13 249 curated relationships between 9503 ncRNAs and 139 CVDs in 12 species. Based on this comprehensive resource, we summarized the regulatory principles of dysregulated ncRNAs in CVDs, including the complex associations between ncRNA and CVDs, tissue specificity and ncRNA synergistic regulation. The highlighted principles are that CVD microRNAs (miRNAs) are highly expressed in heart tissue and that they play central roles in miRNA-miRNA functional synergistic network. In addition, CVD-related miRNAs are close to one another in the functional network, indicating the modular characteristic features of CVD miRNAs. We believe that the regulatory principles summarized here will further contribute to our understanding of ncRNA function and dysregulation mechanisms in CVDs.

MicroRNA-325-3p protects the heart after myocardial infarction by inhibiting RIPK3 and programmed necrosis in mice

BACKGROUND

Receptor-interacting serine-threonine kinase 3 (RIPK3)-mediated necroptosis has been implicated in the progression of myocardial infarction (MI), but the underlying mechanisms, particularly whether microRNAs (miRNAs) are involved, remain largely unknown.

RESULTS

A microarray analysis was used to screen for miR-325-3p expression in myocardial tissues from MI mice, and the expression was confirmed with qRT-PCR. The levels of myocardial enzymes were measured using commercial kits, and an echocardiography system was utilized for the detection of cardiac function parameters. The pathological features and infarction sizes of cardiac tissues were examined using H&E, TCC and Masson's trichrome staining, and the amount of cell apoptosis was determined using an in situ TUNEL assay. Cardiomyocytes were isolated and then subjected to hypoxia induction in vitro. The expression of the RIPK1, RIPK3 and phosphorylated MLKL (p-MLKL) proteins was measured using a Western blot. The mouse cardiomyocyte cell viability was analyzed by an MTT assay. The mRNA target of miR-325-3p was predicted using TargetScan v7.2 and then validated using a dual-luciferase reporter assay. The overexpression of miR-325-3p evidently decreased the expression levels of lactate dehydrogenase (LDH), phosphocreatine kinase (CK), superoxide dismutase (SOD) and malondialdehyde (MDA), inhibited left ventricular end-diastolic diameter (LVEDD) and left ventricular end-systolic diameter (LVESD), and promoted left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVES). In addition, miR-325-3p overexpression attenuated the degree of injury to the cardiac tissue, decreased the infarct sizes and downregulated the expression of the necrosis-related proteins RIPK1, RIPK3 and p-MLKL.

CONCLUSIONS

The RIPK1/RIPK3/p-MLKL axis-induced necroptosis that occurred during MI was mediated by a miRNA module, miR-325-3p, which can effectively ameliorate the symptoms of MI by suppressing the expression of RIPK3.

Identification of microRNAs and genes as biomarkers of atrial fibrillation using a bioinformatics approach

Objective

We aimed to explore potential microRNAs (miRNAs) and target genes related to atrial fibrillation (AF).

Methods

Data for microarrays GSE70887 and GSE68475, both of which include AF and control groups, were downloaded from the Gene Expression Omnibus database. Differentially expressed miRNAs between AF and control groups were identified within each microarray, and the intersection of these two sets was obtained. These miRNAs were mapped to target genes in the miRNet database. Functional annotation and enrichment analysis of these target genes was performed in the DAVID database. The protein-protein interaction (PPI) network from the STRING database and the miRNA-target-gene network were merged into a PPI-miRNA network using Cytoscape software. Modules of this network containing miRNAs were detected and further analyzed.

Results

Ten differentially expressed miRNAs and 1520 target genes were identified. Three PPI-miRNA modules were constructed, which contained miR-424, miR-15a, miR-542-3p, and miR-421 as well as their target genes, CDK1, CDK6, and CCND3.

Conclusion

The identified miRNAs and genes may be related to the pathogenesis of AF. Thus, they may be potential biomarkers for diagnosis and targets for treatment of AF.

Circulating blood cells and extracellular vesicles in acute cardioprotection

During an ST-elevation myocardial infarction (STEMI), the myocardium undergoes a prolonged period of ischaemia. Reperfusion therapy is essential to minimize cardiac injury but can paradoxically cause further damage. Experimental procedures to limit ischaemia and reperfusion (IR) injury have tended to focus on the cardiomyocytes since they are crucial for cardiac function. However, there is increasing evidence that non-cardiomyocyte resident cells in the heart (as discussed in a separate review in this Spotlight series) as well as circulating cells and factors play important roles in this pathology. For example, erythrocytes, in addition to their main oxygen-ferrying role, can protect the heart from IR injury via the export of nitric oxide bioactivity. Platelets are well-known to be involved in haemostasis and thrombosis, but beyond these roles, they secrete numerous factors including sphingosine-1 phosphate (S1P), platelet activating factor, and cytokines that can all strongly influence the development of IR injury. This is particularly relevant given that most STEMI patients receive at least one type of platelet inhibitor. Moreover, there are large numbers of circulating vesicles in the blood, including microvesicles and exosomes, which can exert both beneficial and detrimental effects on IR injury. Some of these effects are mediated by the transfer of microRNA (miRNA) to the heart. Synthetic miRNA molecules may offer an alternative approach to limiting the response to IR injury. We discuss these and other circulating factors, focussing on potential therapeutic targets relevant to IR injury. Given the prevalence of comorbidities such as diabetes in the target patient population, their influence will also be discussed. This article is part of a Cardiovascular Research Spotlight Issue entitled 'Cardioprotection Beyond the Cardiomyocyte', and emerged as part of the discussions of the European Union (EU)-CARDIOPROTECTION Cooperation in Science and Technology (COST) Action, CA16225.

MiRNA-BD: an evidence-based bioinformatics model and software tool for microRNA biomarker discovery

MicroRNAs (miRNAs) are small non-coding RNAs with the potential as biomarkers for disease diagnosis, prognosis and therapy. In the era of big data and biomedical informatics, computer-aided biomarker discovery has become the current frontier. However, most of the computational models are highly dependent on specific prior knowledge and training-testing procedures, very few are mechanism-guided or evidence-based. To the best of our knowledge, untill now no general rules have been uncovered and applied to miRNA biomarker screening. In this study, we manually collected literature-reported cancer miRNA biomarkers and analyzed their regulatory patterns, including the regulatory modes, biological functions and evolutionary characteristics of their targets in the human miRNA-mRNA network. Two evidences were statistically detected and used to distinguish biomarker miRNAs from others. Based on these observations, we developed a novel bioinformatics model and software tool for miRNA biomarker discovery ( http://sysbio.suda.edu.cn/MiRNA-BD/ ). In contrast to routine methods that focus on miRNA synergic functions, our method searches for vulnerable sites in the miRNA-mRNA network and considers the independent regulatory power of miRNAs, i.e., single-line regulations between miRNAs and mRNAs. The performance comparison demonstrates the generality and precision of our model, which identifies miRNA biomarkers for cancers as well as other complex diseases without training or specific prior knowledge.

Emerging Role of mTOR Signaling-Related miRNAs in Cardiovascular Diseases

Mechanistic/mammalian target of rapamycin (mTOR), an atypical serine/threonine kinase of the phosphoinositide 3-kinase- (PI3K-) related kinase family, elicits a vital role in diverse cellular processes, including cellular growth, proliferation, survival, protein synthesis, autophagy, and metabolism. In the cardiovascular system, the mTOR signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of both physiological and pathological processes. MicroRNAs (miRs), a class of short noncoding RNA, are an emerging intricate posttranscriptional modulator of critical gene expression for the development and maintenance of homeostasis across a wide array of tissues, including the cardiovascular system. Over the last decade, numerous studies have revealed an interplay between miRNAs and the mTOR signaling circuit in the different cardiovascular pathophysiology, like myocardial infarction, hypertrophy, fibrosis, heart failure, arrhythmia, inflammation, and atherosclerosis. In this review, we provide a comprehensive state of the current knowledge regarding the mechanisms of interactions between the mTOR signaling pathway and miRs. We have also highlighted the latest advances on mTOR-targeted therapy in clinical trials and the new perspective therapeutic strategies with mTOR-targeting miRs in cardiovascular diseases.

miR-140-5p aggravates hypoxia-induced cell injury via regulating MLK3 in H9c2 cells

Myocardial infarction (MI) is an important cause of cardiovascular disease. microRNAs (miRNAs) have been indicated as pivotal regulators in the physiological and pathological processes of heart diseases. The purpose of this study was to investigate the role of miR-140-5p in hypoxia-induced cell injury in H9c2 cells and its underlying mechanism. H9c2 cells were subjected to hypoxia, before which the expression levels of miR-140-5p and MLK3 were overexpressed or knocked down through transient transfection. The efficiency of transfection was verified by qRT-PCR and Western blotting. Cell viability, apoptotic cell rate, and the expression changes of apoptosis-related proteins were determined by trypan blue exclusion, flow cytometry, and Western blotting, respectively. Furthermore, Western blotting was performed to assess the expression levels of core factors related with p38MAPK and JNK signaling pathways. As a result, hypoxia significantly reduced cell viability and increased cell apoptosis in H9c2 cells. miR-140-5p inhibition attenuated cell injury induced by hypoxia in H9c2 cells, while miR-140-5p overexpression expedited the cell injury, as evidenced by the decreased cell viability and enhanced cell apoptosis. Moreover, miR-140-5p promoted the activation of p38MAPK and JNK pathways. miR-140-5p positively modulated the expression of MLK3. ML3 overexpression reversed the regulatory effects of miR-140-5p inhibition on hypoxia-injured H9c2 cells. In conclusion, this study demonstrated that miR-140-5p aggravated hypoxia-induced cell injury partially through up-regulation of MLK3.

miR-146a deficiency in hematopoietic cells is not involved in the development of atherosclerosis

Background

Atherosclerosis involves activation of the IRAK1/TRAF6/NF-κB inflammatory cascade, which is negatively regulated by miR146a. Previous studies showed that the TT genotype of rs2431697, located near the miR-146a gene, drives lower miR-146a transcription and predicts adverse cardiovascular events in anticoagulated atrial fibrillation patients. Moreover, systemic miR-146a administration protects mice from atherosclerosis. Here we evaluated the ability of miR-146a expression in the hematopoietic component to regulate atherosclerosis in low-density lipoprotein receptor-null mice (Ldlr^-/-).

Methods and results

Lethally-irradiated Ldlr^-/- mice transplanted with bone marrow from wild-type or miR-146a-null mice were fed an atherogenic diet for 8 and 20 weeks. Irak1, Traf6 and MIR146A expression were quantified in thoracic aorta by qRT-PCR and Western blot. Aortic plaque size and composition were characterized by Oil-Red staining and immunohistochemistry and leukocyte recruitment by intravital microscopy. Blood cell counts were similar in fat-fed Ldlr^-/-mice with or without hematopoietic miR-146a expression. However, plasma cholesterol decreased in fat-fed Ldlr^-/-mice transplanted with bone marrow deficient for miR-146a. Finally, aortic atherosclerosis burden and recruitment of leukocytes into the vessel wall were undistinguishable between the two groups, despite higher levels of Irak1 and Traf6 mRNA and protein in the aorta of fat-fed mice lacking hematopoietic miR-146a expression.

Conclusions

miR-146a deficiency exclusively in hematopoietic cells modulates cholesterol levels in plasma and the expression of its targets in the artery wall of fat-fed Ldlr^-/- mice, but does not accelerate atherosclerosis. Atheroprotection upon systemic miR-146a administration may therefore be caused by specific effects on vascular cells.

Detection of Sub-fM DNA with Target Recycling and Self-Assembly Amplification on Graphene Field-Effect Biosensors

All-electronic DNA biosensors based on graphene field-effect transistors (GFETs) offer the prospect of simple and cost-effective diagnostics. For GFET sensors based on complementary probe DNA, the sensitivity is limited by the binding affinity of the target oligonucleotide, in the nM range for 20 mer targets. We report a ∼20 000× improvement in sensitivity through the use of engineered hairpin probe DNA that allows for target recycling and hybridization chain reaction. This enables detection of 21 mer target DNA at sub-fM concentration and provides superior specificity against single-base mismatched oligomers. The work is based on a scalable fabrication process for biosensor arrays that is suitable for multiplexed detection. This approach overcomes the binding-affinity-dependent sensitivity of nucleic acid biosensors and offers a pathway toward multiplexed and label-free nucleic acid testing with high accuracy and selectivity.

Platelets activated by the anti-β2GPI/β2GPI complex release microRNAs to inhibit migration and tube formation of human umbilical vein endothelial cells

Background

Patients with anti-β2GPI antibodies display significantly higher platelet activation/aggregation and vascular endothelial cell damage. The mechanism underlying the correlation between platelet activation, vascular endothelial cell dysfunctions and anti-β2GPI antibodies remains unknown.

Methods

In this study, we derived miR-96 and -26a from platelets activated by the anti-β2GPI/β2GPI complex and explored their role in modulating human umbilical vein endothelial cell (HUVEC) migration and tube formation.

Results

Anti-β2GPI/β2GPI complex induces the release of platelet-derived microparticles (p-MPs). The amounts of miR-96 and -26a in these p-MPs were also higher than for the control group. Co-incubation of HUVECs with p-MPs resulted in the transfer of miR-96 and -26a into HUVECs, where they inhibited migration and tube formation. The targeting role of these miRNAs was further validated by directly downregulating targeted selectin-P (SELP) and platelet-derived growth factor receptor alpha (PDGFRA) via luciferase activity assay.

Conclusion

Our study suggests that miR-96 and -26a in p-MPs can inhibit HUVEC behavior by targeting SELP and PDGFRA.