miR-181c-5p Exacerbates Hypoxia/Reoxygenation-Induced Cardiomyocyte Apoptosis via Targeting PTPN4

MicroRNA-181 in cardiovascular disease: Emerging biomarkers and therapeutic targets

Cardiovascular disease (CVD) is the leading cause of death worldwide. MicroRNAs (MiRNAs) have attracted considerable attention for their roles in several cardiovascular disease states, including both the physiological and pathological processes. In this review, we will briefly describe microRNA-181 (miR-181) transcription and regulation and summarize recent findings on the roles of miR-181 family members as biomarkers or therapeutic targets in different cardiovascular-related conditions, including atherosclerosis, myocardial infarction, hypertension, and heart failure. Lessons learned from these studies may provide new theoretical foundations for CVD.

Divergent cardiac and renal effects of miR-181c-5p inhibition in a rodent heart failure model

Aims

MiR-181c-5p overexpression associates with heart failure (HF) and cardiac damage, but the underlying pathophysiology remains unclear. This study investigated the effect of miR-181c-5p inhibition on cardiac function and fibrosis in a rodent model of diastolic dysfunction, and evaluated additional effects on kidney as relevant comorbid organ.

Methods and results

Diastolic dysfunction was induced in male C57/BL6J mice (n = 20) by combining high-fat diet, L-NG-nitroarginine methyl ester, and angiotensin II administration, and was compared to sham controls (n = 18). Mice were randomized to subcutaneous miR-181c-5p antagomiR (INH) or scrambled antagomiR injections (40 mg/kg/week). HF mice demonstrated diastolic dysfunction and increased fibrosis, which was attenuated by INH treatment. Remarkably, HF + INH animals had a threefold higher mortality rate (60%) compared to HF controls (20%). Histological examination revealed increased glomerular damage in all INH treated mice, and signs of thrombotic microangiopathy (TMA) in mice who died prematurely. Quantitative polymerase chain reaction demonstrated a miR-181c-5p-related downregulation of cardiac but not renal Tgfbr1 in HF + INH mice, while INH treatment reduced renal but not cardiac Vegfa expression in all mice.

Conclusion

This study demonstrates cardiac anti-fibrotic effects of miR-181c-5p inhibition in a rodent HF model through targeting of Tgfbr1 in the heart. Despite improved diastolic function, HF + INH mice had higher mortality due to increased predisposition for TMA, increased renal fibrosis and glomerular damage, associated with Vegfa downregulation in kidneys.

MiR-181c-5p Regulates Lung Adenocarcinoma Progression via Targeting PRKN

Accumulating evidence indicates that microRNAs (miRNAs) have a vital effect on lung adenocarcinoma. However, the contributions and possible mechanisms of miR-181c-5p to lung adenocarcinoma remain largely unclear. Our objective is to clarify the potential mechanism by which miR-181c-5p regulates lung adenocarcinoma progression. RT-qPCR was performed to determine the levels of miR-181c-5p in lung adenocarcinoma tissues and cells. CCK-8 and Transwell assays were conducted to evaluate the viability, migration, and invasion of H460 cells, respectively. The putative target association between miR-181c-5p and the Parkin gene (PRKN) was predicted using miRDB and confirmed by dual-luciferase reporter assay. MiR-181c-5p expression was found to be up-regulated in both lung adenocarcinoma tissues and cells. Suppression of miR-181c-5p resulted in the inhibition of viability, migration, and invasion in lung adenocarcinoma cells. PRKN level was negatively related to miR-181c-5p expression and mediated with the miR-181c-5p's functions on lung adenocarcinoma progression. MiR-181c-5p regulates lung adenocarcinoma progression via targeting PRKN, indicating miR-181c-5p is expected to be a diagnostic and predictive marker for lung adenocarcinoma, providing new insights into the development of treatment strategies for lung adenocarcinoma.

Salvianolic acids and its potential for cardio-protection against myocardial ischemic reperfusion injury in diabetes

The incidence of diabetes and related mortality rate increase yearly in modern cities. Additionally, elevated glucose levels can result in an increase of reactive oxygen species (ROS), ferroptosis, and the disruption of protective pathways in the heart. These factors collectively heighten the vulnerability of diabetic individuals to myocardial ischemia. Reperfusion therapies have been effectively used in clinical practice. There are limitations to the current clinical methods used to treat myocardial ischemia-reperfusion injury. As a result, reducing post-treatment ischemia/reperfusion injury remains a challenge. Therefore, efforts are underway to provide more efficient therapy. Salvia miltiorrhiza Bunge (Danshen) has been used for centuries in ancient China to treat cardiovascular diseases (CVD) with rare side effects. Salvianolic acid is a water-soluble phenolic compound with potent antioxidant properties and has the greatest hydrophilic property in Danshen. It has recently been discovered that salvianolic acids A (SAA) and B (SAB) are capable of inhibiting apoptosis by targeting the JNK/Akt pathway and the NF-κB pathway, respectively. This review delves into the most recent discoveries regarding the therapeutic and cardioprotective benefits of salvianolic acid for individuals with diabetes. Salvianolic acid shows great potential in myocardial protection in diabetes mellitus. A thorough understanding of the protective mechanism of salvianolic acid could expand its potential uses in developing medicines for treating diabetes mellitus related myocardial ischemia-reperfusion.

CircDLGAP4 induces autophagy and improves endothelial cell dysfunction in atherosclerosis by targeting PTPN4 with miR-134-5p

OBJECTIVE

Circular RNAs (circRNAs), a new subgroup of non-coding RNAs in the human transcriptome, are crucial in atherosclerosis (AS). Here, a newly identified circRNA circDLGAP4 was demonstrated to be downregulated in oxidized forms of low-density lipoprotein (ox-LDL)-induced HUVECs.

METHODS

This research adopted ox-LDL to stimulate human umbilical vein endothelial cells (HUVECs) to mimic AS in vitro. To further validate the protective action of circDLGAP4 in AS, a mouse model of AS was constructed with a high-fat diet. Functional assays evaluated circDLGAP4 role in AS in vitro and in vivo. Moreover, mechanism assays evaluated association of circDLGAP4/miR-134-5p/PTPN4.

RESULTS

CircDLGAP4 was induced to promote cell proliferative behavior and autophagy, inhibit apoptotic and inflammatory activities in ox-LDL-treated HUVECs, and attenuated endothelial barrier function. CircDLGAP4 regulated PTPN4 by directly targeting miR-134-5p. Meanwhile, inhibiting miR-134-5p reduced ox-LDL-induced cell dysfunction. Knockout of PTPN4 reversed circDLGAP4 overexpression or miR-134-5p downregulation in vitro. In addition, reducing circDLGAP4 or overexpressing miR-134-5p increased the red atherosclerotic plaque and lesion area of AS mice, reduced autophagy level, and promoted the release of inflammatory cytokines.

CONCLUSION

This study extends the role of circRNA in AS by inducing autophagy and improving endothelial dysfunction in AS via the circDLGAP4/miR-134-5p/PTPN4 axis.

MicroRNA-17-3p protects against excessive posthypoxic autophagy in H9C2 cardiomyocytes via PTEN-Akt-mTOR signaling pathway

The activity of phosphatase and tensin homolog (PTEN) can be inhibited by miR-17-3p, which results in attenuating myocardial ischemia/reperfusion injury (IRI), however, the mechanism behind this phenomenon is still elusive. Suppression of PTEN leads to augmented protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling strength and constrained autophagy activation, which might be the one mechanism for the ameliorated myocardial IRI. Thus, we tested the hypothesis that miR-17-3p attenuated hypoxia/reoxygenation (H/R)-mediated damage in cardiomyocytes by downregulating excessive autophagy via the PTEN-Akt-mTOR axis. The expression of miR-17-3p was remarkably increased after H/R treatment (6-h hypoxia followed by 6-h reoxygenation; H6/R6), which was concomitant with the increase of the release of lactic acid dehydrogenase (cell injury marker) and the enhancement LC3II/I ratio (autophagy markers) in H9C2 cardiomyocytes. Ectoexpression of miR-17-3p agomir led to remarkable augmentation of miR-17-3p expression and evidently attenuated H/R-mediated cell damage and excessive autophagy. Furthermore, an increase in miR-17-3p expression elicited constrained phosphorylation of PTEN (Ser³⁸⁰ ) while enhanced the phosphorylation of Akt (Thr³⁰⁸ , Ser⁴⁷³ ) and mTOR (Ser⁵³⁶ ) after H/R stimulation. In addition, pretreatment with LY-294002 (an Akt selective inhibitor) and rapamycin (an mTOR selective inhibitor) significantly abrogated the protective function of miR-17-3p on H/R-mediated cell damage and autophagy in H9C2 cardiomyocytes. Taken together, these observations indicated that the enhancement of the PTEN/Akt/mTOR axis and the consequent suppression of autophagy overactivation might represent an underlying mechanism by which miR-17-3p attenuated H/R-mediated damage in H9C2 cells.

microRNA-181c-5p stimulates the development of coronary artery disease by targeting SIRT1

OBJECTIVE

MicroRNA (miR) therapeutics is a promising approach to manage coronary artery disease (CAD). Herein, this research was aimed to explore miR-181c-5p-related mechanisms in CAD through regulating SIRT1.

METHODS

A CAD mouse model was established by feeding a high-fat diet in 8-week-old ApoE^-/- mice. miR-181c-5p, SIRT1, and acetylated p65 levels in mouse myocardial tissues were evaluated by RT-qPCR and Western blot. Hemodynamic parameters included the maximum rising rate of the left ventricular pressure (lv + dp/dtmax) and the time values from the onset of contraction to dp/dtmax (t-dp/dtmax), while hemorheological indices included whole blood viscosity (low shear, middle shear, or high shear), plasma viscosity, hematocrit, and platelet adhesion were measured. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 were detected. Mouse pathological changes, degree of fibrosis, and cardiomyocyte apoptosis in myocardial tissues were assessed by HE, Masson, and TUNEL staining, respectively. The targeting relationship between miR-181c-5p and SIRT1 was verified by bioinformatics tools, dual luciferase reporter gene assay, and RNA pull-down assays.

RESULTS

In myocardial tissue of CAD mice, miR-181c-5p and acetylated p65 were upregulated while SIRT1 was downregulated. Downregulating miR-181c-5p or upregulating SIRT1 effectively ameliorated CAD by improving hemodynamics and hemorheology and reducing inflammation, pathological changes, degree of fibrosis, and cardiomyocyte apoptosis in myocardial tissues of mice. miR-181c-5p targeted SIRT1, and overexpression of SIRT1 relieved upregulated miR-181c-5p-induced injuries in CAD mice. Regulating miR-181c-5p and SIRT1 affected the acetylation of p65.

CONCLUSION

Downregulation of miR-181c-5p may ameliorate myocardial pathological changes and cardiomyocyte apoptosis in CAD by upregulating SIRT1 expression and decreasing acetylated p65 levels.

MiR-495-3p depletion contributes to myocardial ischemia/reperfusion injury in cardiomyocytes by targeting TNC

Background

Tenascin-C (TNC) has been found to abnormally express in myocardial ischemia/reperfusion injury (MI/RI), but its effect on cardiomyocytes apoptosis is unknown and is worthy of investigation.

Methods

H9C2 cells were given hypoxia/reoxygenation (H/R) treatment to obtain the replica of MI/RI in vitro. The effect of H/R on viability, apoptosis and inflammation was studied by CCK-8 assay, flow cytometry, mitochondrial membrane potential (MMP) and Ca²⁺ measurements as well as enzyme linked immunosorbent assay. We applied bioinformatics analysis and luciferase reporter assay to screened and validated TNC-targeting miR-495-3p which was then mechanistically investigated by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. With the assistance of cell transfection, rescue assays were conducted.

Results

H9C2 cells showed diminished viability, accelerated apoptosis, elevated tumour necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β), and TNC overexpression in response to H/R induction, while silencing of TNC partially reversed the effect of H/R treatment on the H9C2 cells. TNC silencing reduced Ca²⁺ level and enhanced MMP level in the H/R-stimulated cells. MiR-495-3p targeted TNC and showed a low expression in the H/R-stimulated cells. The expression of TNC was negatively regulated by miR-495-3p. Inhibition of miR-495-3p repressed viability and MMP level, and facilitated apoptosis and levels of Ca²⁺, TNF-α and IL-1β in the H/R-stimulated cells. The effect of TNC silencing and miR-495-3p depletion on H/R-induced cardiomyocyte injury was mutually reversed in vitro.

Conclusion

MiR-495-3p targeted TNC to regulate the apoptosis and inflammation of cardiomyocytes in H/R induction, which was associated with Ca²⁺ overload.

Activation of CCL21-GPR174/CCR7 on cardiac fibroblasts underlies myocardial ischemia/reperfusion injury

Background: The mechanisms underlying myocardial ischemia/reperfusion (I/R) injury are not fully understood. This study aims to explore key candidate genes and potential therapeutic targets for treatment of myocardial I/R injury.

Methods: The transcriptional profiles of ventricular myocardium during cardiac arrest, ischemia, and reperfusion were obtained from the Gene Expression Omnibus database. Based on the transcriptional data of GSE6381, functional pathway and process enrichment analyses, protein–protein interaction network, and gene set enrichment analyses were conducted. In the animal experiments, we established the myocardial I/R injury model in mice. We validated the mRNA and protein expression of the key genes using the qPCR and western blots. We further assessed the expression and localization of CCL21 and its receptors using immunofluorescence staining experiments.

Results: The microarray analyses identified five key genes (CCL21, XCR1, CXCL13, EDN1, and CASR). Myocardial I/R process in mice resulted in significant myocardial infraction, histological damage, and myocardial apoptosis. The results of qPCR and western blots showed that the expression of CCL21 and CXCL13 were increased following myocardial I/R injury in mice. Furthermore, the immunofluorescence staining results revealed that the expression of GPR174/CCR7 (CCL21 receptors), but not CXCR5 (CXCL13 receptor), was elevated following myocardial I/R injury. Moreover, the activated CCL21-GPR174/CCR7 signaling was located on the cardiac fibroblasts of the myocardium with I/R injury.

Conclusion: This study revealed several key factors underlying myocardial I/R injury. Of these, the activation of CCL21-GPR174/CCR7 signaling on cardiac fibroblasts was highlighted, which provides potential therapeutic targets for cardioprotection.

Perspectives for Forkhead box transcription factors in diabetic cardiomyopathy: Their therapeutic potential and possible effects of salvianolic acids

Diabetic cardiomyopathy (DCM) is the primary cause of morbidity and mortality in diabetic cardiovascular complications, which initially manifests as cardiac hypertrophy, myocardial fibrosis, dysfunctional remodeling, and diastolic dysfunction, followed by systolic dysfunction, and eventually end with acute heart failure. Molecular mechanisms underlying these pathological changes in diabetic hearts are complicated and multifactorial, including but not limited to insulin resistance, oxidative stress, lipotoxicity, cardiomyocytes apoptosis or autophagy, inflammatory response, and myocardial metabolic dysfunction. With the development of molecular biology technology, accumulating evidence illustrates that members of the class O of Forkhead box (FoxO) transcription factors are vital for maintaining cardiomyocyte metabolism and cell survival, and the functions of the FoxO family proteins can be modulated by a wide variety of post-translational modifications including phosphorylation, acetylation, ubiquitination, arginine methylation, and O-glycosylation. In this review, we highlight and summarize the most recent advances in two members of the FoxO family (predominately FoxO1 and FoxO3a) that are abundantly expressed in cardiac tissue and whose levels of gene and protein expressions change as DCM progresses, with the goal of providing valuable insights into the pathogenesis of diabetic cardiovascular complications and discussing their therapeutic potential and possible effects of salvianolic acids, a natural product.

Caloric restriction-mimetics for the reduction of heart failure risk in aging heart: with consideration of gender-related differences

The literature is full of claims regarding the consumption of polyphenol or polyamine-rich foods that offer some protection from developing cardiovascular disease (CVD). This is achieved by preventing cardiac hypertrophy and protecting blood vessels through improving the function of endothelium. However, do these interventions work in the aged human hearts? Cardiac aging is accompanied by an increase in left ventricular hypertrophy, along with diastolic and systolic dysfunction. It also confers significant cardiovascular risks for both sexes. The incidence and prevalence of CVD increase sharply at an earlier age in men than women. Furthermore, the patterns of heart failure differ between sexes, as do the lifetime risk factors. Do caloric restriction (CR)-mimetics, rich in polyphenol or polyamine, delay or reverse cardiac aging equally in both men and women? This review will discuss three areas: (1) mechanisms underlying age-related cardiac remodeling; (2) gender-related differences and potential mechanisms underlying diminished cardiac response in older men and women; (3) we select a few polyphenol or polyamine rich compounds as the CR-mimetics, such as resveratrol, quercetin, curcumin, epigallocatechin gallate and spermidine, due to their capability to extend health-span and induce autophagy. We outline their abilities and issues on retarding aging in animal hearts and preventing CVD in humans. We discuss the confounding factors that should be considered for developing therapeutic strategies against cardiac aging in humans.

Integrated analysis of miRNA-mRNA interaction in pediatric dilated cardiomyopathy

BACKGROUND

MicroRNAs (miRNAs) are short single-stranded nucleotides that can regulate gene expression. Although we previously evaluated the expression of miRNAs in pediatric dilated cardiomyopathy (DCM) by miRNA array, pathway prediction based on changes in mRNA expression has not been previously analyzed in this population. The current study aimed to determine the regulation of miRNA expression by miRNA-sequencing (miRNA-seq) and, through miRNA-sequencing (mRNA-seq), analyze their putative target genes and altered pathways in pediatric DCM hearts.

METHODS

miRNA expression was determined by miRNA-seq [n = 10 non-failing (NF), n = 20 DCM]. Expression of a subset of miRNAs was evaluated in adult DCM patients (n = 11 NF, n = 13 DCM). miRNA-mRNA prediction analysis was performed using mRNA-seq data (n = 7 NF, n = 7 DCM) from matched samples.

RESULTS

Expression of 393 miRNAs was significantly different (p < 0.05) in pediatric DCM patients compared to NF controls. TargetScan-based miRNA-mRNA analysis revealed 808 significantly inversely expressed genes. Functional analysis suggests upregulated pathways related to the regulation of stem cell differentiation and cardiac muscle contraction, and downregulated pathways related to the regulation of protein phosphorylation, signal transduction, and cell communication.

CONCLUSIONS

Our results demonstrated a unique age-dependent regulation of miRNAs and their putative target genes, which may contribute to distinctive phenotypic characteristics of DCM in children.

IMPACT

This is the first study to compare miRNA expression in the heart of pediatric DCM patients to age-matched healthy controls by RNA sequencing. Expression of a subset of miRNAs is uniquely dysregulated in children. Using mRNA-seq and miRNA-seq from matched samples, target prediction was performed. This study underscores the importance of pediatric-focused studies.

MicroRNA-503 Exacerbates Myocardial Ischemia/Reperfusion Injury via Inhibiting PI3K/Akt- and STAT3-Dependent Prosurvival Signaling Pathways

Acute myocardial infarction is a leading cause of death worldwide, while restoration of blood flow to previously ischemic myocardium may lead to ischemia/reperfusion (I/R) injury. Accumulated evidence shows that microRNAs play important roles in cardiovascular diseases. However, the potential role of microRNA-503 (miR-503) in myocardial I/R injury is little known. Thus, this study is aimed at determining whether and how miR-503 affects myocardial I/R injury in vivo and in vitro. A mouse model of myocardial I/R injury and H9c2 cell model of hypoxia/reoxygenation (H/R) injury were established. The postischemic cardiac miR-503 was downregulated in vivo and in vitro. Mechanistically, PI3K p85 and Bcl-2 are miR-503 targets. The post-ischemic cardiac PI3K p85 protein level was decreased in vivo. Agomir-503 treatment exacerbated H/R-induced injuries manifested as decreased cell viability, increased lactate dehydrogenase activity, and cell apoptosis. Agomir-503 treatment reduced cell viability under normoxia as well and reduced both PI3K p85 and Bcl-2 protein levels under either normoxia or H/R condition. It reduced phosphorylation of Stat3 (p-Stat3-Y705) and Akt (T450) in cells subjected to H/R. In contrast, Antagomir-503 treatment attenuated H/R injury and increased p-Stat3 (Y705) under normoxia and increased p-Akt (T450) under either normoxia or H/R condition. It is concluded that miR-503 exacerbated I/R injury via inactivation of PI3K/Akt and STAT3 pathways and may become a therapeutic target in preventing myocardial I/R injury.

The Role of MicroRNA in DNA Damage Response

DNA is essential for the development and function of organisms. A number of factors affect DNA integrity and cause DNA damages, such as ultraviolet light, ionizing radiation and hydrogen peroxide. DNA damages activate a series of intracellular reactions, called DNA damage response, which play a crucial role in the pathogenesis of cancers and other diseases. MiRNA is a type of evolutionarily conserved non-coding RNA and affects the expression of target genes by post-transcriptional regulation. Increasing evidences suggested that the expression of some miRNAs was changed in tumor cases. MiRNAs may participate in DNA damage response and affect genomic stability via influencing the processes of cell cycle, DNA damage repair and apoptosis, thus ultimately impact on tumorigenesis. Therefore, the role of miRNA in DNA damage response is reviewed, to provide a theoretical basis for the mechanism of miRNAs’ effects on DNA damage response and for the research of new therapies for diseases.

Mechanism of miR-126 in hypoxia-reoxygenation-induced cardiomyocyte pyroptosis by regulating HMGB1 and NLRP3 inflammasome

OBJECTIVE

Pyroptosis refers to the programmed cell death. This study evaluated the mechanism of miR-126 in hypoxia-reoxygenation (HR)-induced cardiomyocyte pyroptosis.

METHODS

The HR rat cardiomyocyte models were established. The cell viability, cytotoxicity, and levels of miR-126, pro-caspase-1 (p45), activated caspase-1 (p20/p10), caspase-11, gasdermin D (GSDMD), and GSDMD-N were detected. The cells were transfected with miR-126 mimics to verify the effect on rat cardiomyocyte pyroptosis, and added with HMGB1 inhibitor (Glycyrrhizin) or NLRP3 inhibitor (S3680) to explore the regulatory mechanisms on rat cardiomyocyte pyroptosis. The binding relationship of miR-126 and HMGB1 was explored. The regulatory effect of miR-126 and HMGB1 on HR-stimulated cardiomyocytes was verified through co-transfection with miR-126 mimics and pcDNA3.1-HMGB1.

RESULTS

HR treatment inhibited rat cardiomyocyte viability and increased cytotoxicity. After HR treatment, pro-caspase-1 (p45), activated caspase-1 (p20/p10), caspase-11, GSDMD, and GSDMD-N were elevated in rat cardiomyocytes, while miR-126 was evidently downregulated in rat cardiomyocytes. miR-126 overexpression, and inhibition of HMGB1 or NLRP3 partially reversed HR-induced rat cardiomyocyte cytotoxicity and pyroptosis. miR-126 targeted HMGB1 and HMGB1 overexpression partly reversed the inhibition of miR-126 overexpression on HR-induced cardiomyocyte pyroptosis.

CONCLUSION

miR-126 inhibits HMGB1/NLRP3 activity and the caspase-1/11 activation and reduces the GSDMD-N cleaved from GSDMD, ultimately inhibiting HR-induced cardiomyocyte pyroptosis.

MicroRNA-181c-5p modulates phagocytosis efficiency in bone marrow-derived macrophages

OBJECTIVE AND DESIGN

Phagocytosis and clearance of apoptotic cells are essential for inflammation resolution, efficient wound healing, and tissue homeostasis. MicroRNAs are critical modulators of macrophage polarization and function. The current study aimed to investigate the role of miR-181c-5p in macrophage phagocytosis.

MATERIALS AND METHODS

miR-181c-5p was identified as a potential candidate in microRNA screening of RAW264.7 macrophages fed with apoptotic cells. To investigate the role of miR-181c-5p in phagocytosis, the expression of miR-181c-5p was assessed in phagocyting bone marrow-derived macrophages. Phagocytosis efficiency was measured by fluorescence microscopy. Gain- and loss-of-function studies were performed using miR-181c-5p-specific mimic and inhibitor. The expression of the phagocytosis-associated genes and proteins of interest was evaluated by RT² profiler PCR array and western blotting, respectively.

RESULTS

miR-181c-5p expression was significantly upregulated in the phagocyting macrophages. Furthermore, mimic-induced overexpression of miR-181c-5p resulted in the increased phagocytic ability of macrophages. Moreover, overexpression of miR-181c-5p resulted in upregulation of WAVE-2 in phagocyting macrophages, suggesting that miR-181c-5p may regulate cytoskeletal arrangement during macrophage phagocytosis.

CONCLUSION

Altogether, our data provide a novel function of miR-181c-5p in macrophage biology and suggest that targeting macrophage miR-181c-5p in injured tissues might improve clearance of dead cells and lead to efficient inflammation resolution.

Friend or foe? Unraveling the complex roles of protein tyrosine phosphatases in cardiac disease and development

Regulation of protein tyrosine phosphorylation is critical for most, if not all, fundamental cellular processes. However, we still do not fully understand the complex and tissue-specific roles of protein tyrosine phosphatases in the normal heart or in cardiac pathology. This review compares and contrasts the various roles of protein tyrosine phosphatases known to date in the context of cardiac disease and development. In particular, it will be considered how specific protein tyrosine phosphatases control cardiac hypertrophy and cardiomyocyte contractility, how protein tyrosine phosphatases contribute to or ameliorate injury induced by ischaemia / reperfusion or hypoxia / reoxygenation, and how protein tyrosine phosphatases are involved in normal heart development and congenital heart disease. This review delves into the newest developments and current challenges in the field, and highlights knowledge gaps and emerging opportunities for future research.

Donepezil ameliorates oxygen‑glucose deprivation/reoxygenation‑induced cardiac microvascular endothelial cell dysfunction through PARP1/NF‑κB signaling

Ischemia/reperfusion (I/R) injury is a serious clinical condition characterized by high morbidity and mortality rates. Donepezil plays a neuroprotective role in I/R-associated diseases. The aim of the present study was to investigate the role and the potential mechanism of action of donepezil in I/R-induced myocardial microvascular endothelial cell dysfunction. An I/R model was simulated using oxygen-glucose deprivation/reoxygenation (OGD/R) injury in human cardiac microvascular endothelial cells (CMECs). Cell viability and lactate dehydrogenase release were examined following treatment with donepezil. Commercial kits were used to evaluate cell apoptosis, cell permeability and caspase-3 activity. The expression levels of apoptosis-associated proteins, as well as proteins found in tight junctions or involved in the poly(ADP-ribose) polymerase 1 (PARP1)/NF-κB pathway, were measured using western blotting. These parameters were also examined following PARP1 overexpression. The results demonstrated that donepezil increased cell viability and reduced toxicity in OGD/R-treated CMECs. The apoptotic rate, caspase-3 activity and protein expression levels of Bax and cleaved caspase-3 were significantly reduced following donepezil treatment, which was accompanied by Bcl-2 upregulation. Moreover, cell permeability was notably reduced, coupled with a marked increase in the expression of tight junction-associated proteins. The expression levels of proteins related to PARP1/NF-κB signaling were significantly downregulated in CMECs following donepezil treatment. However, the protective effects of donepezil on OGD/R-induced CMEC injury were reversed following PARP1 overexpression. In conclusion, donepezil suppressed OGD/R-induced CMEC dysfunction via PARP1/NF-κB signaling. This finding provided insight into the mechanism underlying myocardial I/R injury.

Altered Circulating MicroRNA Profiles After Endurance Training: A Cohort Study of Ultramarathon Runners

Background

Despite the positive effects of endurance training on the cardiovascular (CV) system, excessive exercise induces not only physiological adaptations but also adverse changes in CV system, including the heart. We aimed to evaluate the selected miRNAs expression based on bioinformatic analysis and their changes before and after an ultramarathon run.

Materials and Methods

Cardiac tissue-specific targets were identified with the Tissue 2.0 database. Gene-gene interaction data were retrieved from the STRING app for Cytoscape. Twenty-three endurance athletes were recruited to the study. Athletes ran to completion (100 km) or exhaustion (52–91 km, median 74 km). All participants completed pre- and post-run testing. miRNAs expressions were measured both before and after the race.

Results

Enrichment analysis of the signaling pathways associated with the genes targeted by miRNAs selected for qRT-PCR validation (miR-1-3p, miR-126, miR-223, miR-125a-5p, miR-106a-5p, and miR-15a/b). All selected miRNAs showed overlap in regulation in pathways associated with cancer, IL-2 signaling, TGF-β signaling as well as BDNF signaling pathway. Analysis of metabolites revealed significant regulation of magnesium and guanosine triphosphate across analyzed miRNA targets. MiR-1-3p, miR-125a-5p, miR-126, and miR-223 expressions were measured in 23 experienced endurance athletes, before and after an ultramarathon wherein athletes ran to completion (100 km) or exhaustion (52–91 km, median 74 km). The expressions of miR-125a-5p, miR-126, and miR-223 were significantly increased after the race (p = 0.007, p = 0.001, p = 0.014, respectively). MiR-1-3p expression post-run showed a negative correlation with the post-run levels of high-sensitivity C-reactive protein (hs-CRP) (r = −0.632, p = 0.003). Higher miR-1-3p expression was found in runners, who finished the race under 10 h compared to runners who finished over 10 h (p = 0.001). Post-run miR-125a-5p expression showed a negative correlation with the peak lactate during the run (r = −0.576, p = 0.019).

Conclusion

Extreme physical activity, as exemplified by an ultramarathon, is associated with changes in circulating miRNAs’ expression related to inflammation, fibrosis, and cardiac muscle function. In particular, the negative correlations between miR-125a-5p and lactate concentrations, and miR-1-3p and hs-CRP, support their role in specific exercise-induced adaptation. Further studies are essential to validate the long-term effect of these observations.

Long non-coding RNA muscleblind like splicing regulator 1 antisense RNA 1 (LncRNA MBNL1-AS1) promotes the progression of acute myocardial infarction by regulating the microRNA-132-3p/SRY-related high-mobility-group box 4 (SOX4) axis

Long non-coding RNA muscleblind like splicing regulator 1 antisense RNA 1 (LncRNA MBNL1-AS1) exerts vital role in various physiological processes. However, its functions in acute myocardial infarction (AMI) are not elucidated. AMI model was constructed using Wistar rats and it was found that LncRNA MBNL1-AS1 was upregulated in AMI model according to the quantitative real-time polymerase chain reaction (qRT-PCR) results. The left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP) and maximum rate of rise/fall of left ventricle pressure (±dp/dt max) were detected through hemodynamics test, which showed that knockdown of MBNL1-AS1 improved cardiac function in AMI model. Next, the myocardial infarction area was estimated by triphenyltetrazole chloride (TTC) staining, and the levels of cardiac troponin I (cTn-I) and creatine kinase-MB (CK-MB) were detected by enzyme-linked immunosorbent assay (ELISA) kit. The results revealed that silencing MBLN1-AS1 alleviated myocardial injury in AMI model. Additionally, MBNL1-AS1 knockdown inhibited apoptosis of myocardial cells and reduced the expression of apoptotic proteins. According to DIANA database and luciferase reporter assay, miR-132-3p was the direct target of MBNL1-AS1 and was negatively regulated by MBNL1-AS1. Furthermore, Targetscan database predicted that SRY-related high-mobility-group box 4 (SOX4) was the direct target of miR-132-3p and was regulated by MBNL1-AS1 through miR-132-3p. Moreover, overexpression of SOX4 partially eliminated effects of MBNL1-AS1 on myocardial cells. In conclusion, this investigation for the first time revealed that LncRNA MBNL1-AS1 was the potential target for treating AMI and expounded the underlying mechanisms of it.

CPNE3 interaction with RACK1 protects against myocardial ischemia/reperfusion injury

Copine 3 (CPNE3) and receptor for activated C kinase 1 (RACK1) have been determined to be risk factors for patients with acute myocardial ischemia/reperfusion (I/R). The present study aimed to evaluate the role of CPNE3 and its interaction with RACK1 in myocardial (I/R) injury. Reverse transcription-quantitative PCR (RT-qPCR) and western blotting were performed to detect CPNE3 and RACK1 expression levels in H9c2 cells before and after the transfection of CPNE3 overexpression plasmid or small interfering RNA-RACK1. Cell viability was detected using a Cell Counting Kit-8 assay, and immunoprecipitation assays were performed to determine the interaction between CPNE3 and RACK1. A commercial kit was used to examine lactate dehydrogenase (LDH) levels. The expression levels of inflammatory cytokines were detected via RT-qPCR and western blotting. Cell apoptosis was assessed via TUNEL staining and western blotting. The results demonstrated that the expression levels of CPNE3 and RACK1 were decreased in hypoxia/reoxygenation (H/R)-induced H9c2 cardiomyocytes, which was consistent with the expression levels observed in the myocardial I/R injury rat model. It was found that CPNE3 overexpression upregulated RACK1 expression, increased cell viability and suppressed the release of LDH in H/R-induced H9c2 cells. Furthermore, CPNE3 overexpression inhibited the release of inflammatory cytokines and decreased cell apoptosis in H/R-induced cardiomyocytes by activating RACK1 expression. The present study suggested that CPNE3 served an important role in preventing I/R injury by interacting with RACK1, providing novel insight into the prevention of myocardial I/R injury, as well as the treatment and care of patients with myocardial I/R.

miRNA-19b-3p Stimulates Cardiomyocyte Apoptosis Induced by Myocardial Ischemia Reperfusion via Downregulating PTEN

Objective

To clarify the function of miRNA-19b-3p in accelerating myocardial ischemia-reperfusion injury- (MIRI-) induced cardiomyocyte apoptosis by downregulating gene of phosphate and tension homology deleted on chromsome ten (PTEN), thus influencing the progression of acute myocardial infarction.

Materials and Methods

miRNA-19b-3p and PTEN levels in HCM cells undergoing hypoxia/reoxygenation (H/R) were determined. Meanwhile, activities of myocardium injury markers [lactate dehydrogenase (LDH), malondialdehyde; malonic dialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX)] in H/R-induced HCM cells were tested. Through dual-luciferase reporter gene assay, the binding between miRNA-19b-3p and PTEN was verified. Regulatory effects of miRNA-19b-3p and PTEN on apoptotic rate and apoptosis-associated gene expressions (proapoptotic protein Bcl-2 associated X protein (Bax), antiapoptotic protein B-cell lymphoma-2 (Bcl-2), and cytochrome C) in H/R-induced human cardiac myocytes (HCM) cells were examined.

Results

miRNA-19b-3p was upregulated, while PTEN was downregulated in H/R-induced HCM cells. Knockdown of miRNA-19b-3p decreased activities of LDH, MDA, and GSH-PX, but increased SOD level in H/R-induced HCM cells. The binding between miRNA-19b-3p and PTEN was confirmed. More importantly, knockdown of miRNA-19b-3p reduced apoptotic rate, downregulated proapoptosis gene expressions (Bax and cytochrome C), and upregulated antiapoptosis gene expression (Bcl-2), which were reversed by silence of PTEN.

Conclusions

miRNA-19b-3p is upregulated in HCM cells undergoing hypoxia and reoxygenation, which accelerates MIRI-induced cardiomyocyte apoptosis through downregulating PTEN.

Circ_0030235 knockdown protects H9c2 cells against OGD/R-induced injury via regulation of miR-526b

Backgrounds

Acute myocardial infarction (MI) is the common clinical manifestation of coronary heart disease. Circular RNAs (circRNAs) act key roles in cardiomyocytes growth and angiogenesis. However, their functions in MI are not entirely clear. This research intended to investigate the role and underlying mechanisms of circ_0030235 in H9c2 cells.

Methods

H9c2 cells were conducted to oxygen glucose deprivation/reperfusion (OGD/R) inducement to establish the MI model. Circ_0030235 and miR-526b expression was tested and altered by qRT-PCR and transfection. Cell viability, apoptosis and reactive oxygen species (ROS) injury were tested by CCK-8 assay, TUNEL assay kit, and ROS Detection Assay Kit, respectively. Assessment of cell injury-related factors was performed by employing ELISA, Mitochondrial Viability Staining and the JC-1-Mitochondrial Membrane Potential Assay Kit. The relationship between circ_0030235 and miR-526b was analyzed by dual luciferase reporter assay. The expression of key proteins was analyzed by western blot.

Results

Circ_0030235 was highly expressed in OGD/R-induced H9c2 cells. OGD/R inducement cell viability, while accelerated apoptosis. Besides, the level ROS, cell injury-related factors, mitochondrial membrane potential were notably elevated by OGD/R inducement, while mitochondrial viability was remarkably declined. Whereas, these impacts were all noticeably remitted by circ_0030235 knockdown. miR-526b was a target of circ_0030235. Circ_0030235 knockdown-induced impacts were all notably abrogated by miR-526b inhibition, including the activating impacts on PI3K/AKT and MEK/ERK pathways.

Conclusions

This research implied that circ_0030235 knockdown might remit OGD/R-induced impacts via activation of PI3K/AKT and MEK/ERK pathways and regulation of miR-526b.

Long‑chain non‑coding RNA GAS5 promotes cell autophagy by modulating the miR‑181c‑5p/ATG5 and miR‑1192/ATG12 axes

The main aim of the present study was to explore the role of long-chain non-coding RNA (lncRNA) growth arrest-specific transcript 5 (GAS5) in macrophage autophagy. Firstly, the expression of lncRNA GAS5 during cell starvation or following treatment with 3-methyladenine was determined using reverse transcription-quantitative PCR (RT-qPCR). Additionally, fluorescent in situ hybridization (FISH) assay was utilized to determine the localization of the expression of lncRNA GAS5 in RAW264.7 cells. In vitro cell models were established through the transfection of LV5-lncRNA GAS5 (LV5-GAS5) or LV3-shRNA-lnc GAS5 (sh-GAS5), in order to overexpress or knockdown lncRNA GAS5 expression in RAW264.7 cells. The potential target microRNAs (miRNAs/miRs) of lncRNA GAS5 were analyzed using bioinformatics. The formation of autophagic bodies was detected with the use of laser confocal and transmission electron microscopy. Dual-luciferase reporter assay was performed to determine the target specificities of miR-181c-5p or miR-1192 to lncRNA GAS5 and autophagy-related gene (ATG) or ATG12. The mRNA levels of miR181c-5p, miR-1192, as well as ATG5 and ATG12 were detected using RT-qPCR. The protein levels of microtubule-associated proteins 1A/1B light chain 3B (LC3), p62, ATG5 and ATG12 were measured using western blot analysis. It was revealed that lncRNA GAS5 expression in RAW264.7 macrophages increased significantly during starvation-induced autophagy, and that lncRNA GAS5 overexpression was able to markedly promote the formation of autophagic bodies. Bioinformatics analysis demonstrated that miR-181c-5p and miR-1192 were potential targets of lncRNA GAS5, which was further confirmed by RT-qPCR, western blot analysis and the dual-luciferase reporter assay. Finally, it was confirmed that lncRNA GAS5 promoted autophagy by sponging miR-181c-5p and miR-1192, and upregulating the expression levels of the key autophagic regulators, ATG5 and ATG12. On the whole, the present study demonstrates that total, lncRNA GAS5 promotes macrophage autophagy by targeting the miR-181c-5p/ATG5 and miR-1192/ATG12 axes.

The Role of miR-181c in Mechanisms of Diabetes-Impaired Angiogenesis: An Emerging Therapeutic Target for Diabetic Vascular Complications

Diabetes mellitus is estimated to affect up to 700 million people by the year 2045, contributing to an immense health and economic burden. People living with diabetes have a higher risk of developing numerous debilitating vascular complications, leading to an increased need for medical care, a reduced quality of life and increased risk of early death. Current treatments are not satisfactory for many patients who suffer from impaired angiogenesis in response to ischaemia, increasing their risk of ischaemic cardiovascular conditions. These vascular pathologies are characterised by endothelial dysfunction and abnormal angiogenesis, amongst a host of impaired signaling pathways. Therapeutic stimulation of angiogenesis holds promise for the treatment of diabetic vascular complications that stem from impaired ischaemic responses. However, despite significant effort and research, there are no established therapies that directly stimulate angiogenesis to improve ischaemic complications such as ischaemic heart disease and peripheral artery disease, highlighting the immense unmet need. However, despite significant effort and research, there are no established therapies that directly stimulate angiogenesis in a clinical setting, highlighting the immense unmet need. MicroRNAs (miRNAs) are emerging as powerful targets for multifaceted diseases including diabetes and cardiovascular disease. This review highlights the potential role of microRNAs as therapeutic targets for rescuing diabetes-impaired angiogenesis, with a specific focus on miR-181c, which we have previously identified as an important angiogenic regulator. Here we summarise the pathways currently known to be regulated by miR-181c, which include the classical angiogenesis pathways that are dysregulated in diabetes, mitochondrial function and axonal guidance, and describe how these relate both directly and indirectly to angiogenesis. The pleiotropic actions of miR-181c across multiple key angiogenic signaling pathways and critical cellular processes highlight its therapeutic potential as a novel target for treating diabetic vascular complications.

Cell type-specific microRNA therapies for myocardial infarction

Current interventions fail to recover injured myocardium after infarction and prompt the need for development of cardioprotective strategies. Of increasing interest is the therapeutic use of microRNAs to control gene expression through specific targeting of mRNAs. In this Review, we discuss current microRNA-based therapeutic strategies, describing the outcomes and limitations of key microRNAs with a focus on target cell types and molecular pathways. Last, we offer a perspective on the outlook of microRNA therapies for myocardial infarction, highlighting the outstanding challenges and emerging strategies.

Downregulation of lncRNA SNHG14 alleviates neurons injury by modulating the miR-181c-5p/BMF axis in ischemic stroke

PURPOSE

Our study aims to explore the role and mechanism of lncRNA small nucleolar RNA host gene 14 (SNHG14) in brain injury caused by ischemic stroke (IS).

METHODS

Middle cerebral artery occlusion (MCAO) model and oxygen-glucose deprivation (OGD)-induced primary cortical neurons were used to construct in vitro and in vivo models of IS, respectively. Relative SNHG14, miR-181c-5p and Bcl-2-modifying factor (BMF) expression levels were detected by quantitative real-time PCR. MTT assay, EdU staining and flow cytometry were used to measure cell proliferation and apoptosis. The protein levels of apoptosis marker and BMF were determined using western blot analysis. ELISA assay was performed to assess cell inflammatory response and injury.

RESULTS

SNHG14 was upregulated and miR-181c-5p was downregulated in MCAO model and OGD-induced primary cortical neurons. Silencing of SNHG14 markedly promoted proliferation, restrained apoptosis and inflammatory response in OGD-induced primary cortical neurons to alleviate neurons injury. In terms of mechanism, miR-181c-5p could be sponged by SNHG14, and its inhibitor reversed the inhibition effect of SNHG14 silencing on OGD-induced neurons injury. Also, BMF was a target of miR-181c-5p, and its overexpression could reverse the suppressive effect of miR-181c-5p on OGD-induced neurons injury. Our data uncovered that BMF expression was positively regulated by SNHG14 and negatively regulated by miR-181c-5p.

CONCLUSION

Our results indicated that SNHG14 promoted neurons injury through regulating miR-181c-5p/BMF axis, suggesting that SNHG14 might be a potential target to alleviate IS-induced brain injury.

miR-16-5p Regulates PTPN4 and Affects Cardiomyocyte Apoptosis and Autophagy Induced by Hypoxia/Reoxygenation

Objectives

To explore the effects of miR-16-5p and PTPN4 on the apoptosis and autophagy of AC16 cardiomyocytes after hypoxia/reoxygenation treatment.

Methods

AC16 cells were divided into the control group (NC), hypoxia/reoxygenation group (H/R), knockdown miR-16-5p negative control group (NC inhibitor), knockdown miR-16-5p group (miR-16-5p inhibitor), overexpression miR-16-5p negative control group (NC mimics), overexpression miR-16-5p group (miR-16-5p mimics), silent PTPN4 negative control group (sh-NC), silent PTPN4 group (sh-PTPN4), and silent PTPN4 + knockdown miR-16-5p group (sh-PTPN4 + miR-16-5p inhibitor). Real-time fluorescent quantitative PCR (RT-qPCR) and western blotting (WB) were used to measure the expression level of miR-16-3p, miR-16-5p, protein tyrosine phosphatase nonreceptor type 4 (PTPN4), and autophagy-related proteins (beclin-1, LC3 II/I, and P26) in AC16 cells. The apoptosis level of AC16 cells in each group was measured by flow cytometry and TUNEL. The dual-luciferase reporter gene experiment was also used to verify the targeting relationship between miR-16-5p and PTPN4.

Results

After H/R treatment, the levels of myocardial injury markers including LDH and CK-MB in AC16 cells were increased significantly (P < 0.05), and the levels of cell apoptosis and autophagy also increased significantly (P < 0.05). The level of miR-16-3p in AC16 cells did not change significantly after H/R treatment, whereas the level of miR-16-5p was increased significantly (P < 0.05). After miR-16-5p was knocked down, the levels of LDH and CK-MB in AC16 cells treated with H/R were significantly reduced (P < 0.05), and the rates of cell apoptosis and autophagy were also significantly reduced (P < 0.05). miR-16-5p negatively regulated the expression level of PTPN4 protein in AC16 cells (P < 0.05), and the dual-luciferase reporter gene experiment confirmed that PTPN4 was the downstream target of miR-16-5p. Silencing of PTPN4 significantly increased the damage of AC16 cells induced by H/R treatment (P < 0.05), but simultaneously inhibiting the expression of PTPN4 and miR-16-5p reversed the protective effect of miR-16-5p knockdown on AC16 cells (P < 0.05).

Conclusions

The expression of miR-16-5p is upregulated in AC16 cells after H/R treatment and the knockdown which can protect AC16 cells from H/R-induced cell damage that may be due to its regulation on the expression of PTPN4.

Epigenetic role of N6-methyladenosine (m6A) RNA methylation in the cardiovascular system

As the most prevalent and abundant transcriptional modification in the eukaryotic genome, the continuous and dynamic regulation of N6-methyladenosine (m6A) has been shown to play a vital role in physiological and pathological processes of cardiovascular diseases (CVDs), such as ischemic heart failure (HF), myocardial hypertrophy, myocardial infarction (MI), and cardiomyogenesis. Regulation is achieved by modulating the expression of m6A enzymes and their downstream cardiac genes. In addition, this process has a major impact on different aspects of internal biological metabolism and several other external environmental effects associated with the development of CVDs. However, the exact molecular mechanism of m6A epigenetic regulation has not been fully elucidated. In this review, we outline recent advances and discuss potential therapeutic strategies for managing m6A in relation to several common CVD-related metabolic disorders and external environmental factors. Note that an appropriate understanding of the biological function of m6A in the cardiovascular system will pave the way towards exploring the mechanisms responsible for the development of other CVDs and their associated symptoms. Finally, it can provide new insights for the development of novel therapeutic agents for use in clinical practice.

CircPTK2-miR-181c-5p-HMGB1: a new regulatory pathway for microglia activation and hippocampal neuronal apoptosis induced by sepsis

BACKGROUND

Circular RNA hsa_circ_0008305 (circPTK2), miR-181c-5p and High mobility group box-1 (HMGB1) had a targeted regulatory relationship through bioinformatics analysis. This study explained the effects of these genes in microglia and sepsis mice.

METHODS

Lipopolysaccharide (LPS) or Cecal Ligation and Puncture (CLP) was used to induce inflammation cell model or sepsis mouse model, as needed. Gene levels were measured by enzyme linked immunosorbent assay (ELISA), quantitative real-time PCR or Western blot, as required. Apoptosis was detected by TUNEL assay, and RNase R was used to test the stability of circPTK2. Targeting relationships between genes were analyzed using bioinformatics analysis and dual luciferase assay. Morris water maze test and mitochondrial membrane potential (MMP) detection were conducted to analyze the effects of genes on cognitive dysfunction of mice.

RESULTS

Lipopolysaccharide induction triggered the release of pro-inflammatory cytokines, the upregulation of HMGB1 and circPTK2, and the downregulation of miR-181c-5p in microglia. Overexpression of HMGB1 enhanced the effect of LPS, while silencing HMGB1 partially counteracted the effect of LPS. Moreover, miR-181c-5p was a target of circPTK2 and bound to HMGB1. MiR-181c-5p mimic partially reversed the functions of LPS and HMGB1 overexpression, reduced the levels of TNF-α, IL-1β, and HMGB1, and inhibited apoptosis. CircPTK2 knockdown had the same effect as miR-181c-5p up-regulation. In vivo, sicircPTK2 improved cognitive function, restored MMP level, inhibited apoptosis, reduced the levels of inflammatory factors and apoptotic factors, and increased the survival rate of CLP-induced mice.

CONCLUSION

Our research reveals that circPTK2 regulates microglia activation and hippocampal neuronal apoptosis induced by sepsis via miR-181c-5p-HMGB1 signaling.

Roles of noncoding RNAs in the initiation and progression of myocardial ischemia-reperfusion injury

The morbidity and mortality of myocardial ischemia-reperfusion injury (MIRI) have increased in modern society. Noncoding RNAs (ncRNAs), including lncRNAs, circRNAs, piRNAs and miRNAs, have been reported in a variety of studies to be involved in pathological initiation and developments of MIRI. Hence this review focuses on the current research regarding these ncRNAs in MIRI. We comprehensively introduce the important features of lncRNAs, circRNAs, piRNA and miRNAs and then summarize the published studies of ncRNAs in MIRI. A clarification of lncRNA-miRNA-mRNA, lncRNA-transcription factor-mRNA and circRNA-miRNA-mRNA axes in MIRI follows, to further elucidate the crucial roles of ncRNAs in MIRI. Bioinformatics analysis has revealed the biological correlation of mRNAs with MIRI. We provide a comprehensive perspective for the roles of these ncRNAs and their related networks in MIRI, providing a theoretical basis for preclinical and clinical studies on ncRNA-based gene therapy for MIRI treatment.

The Causes and Consequences of miR-503 Dysregulation and Its Impact on Cardiovascular Disease and Cancer

microRNAs (miRs) are short, non-coding RNAs that regulate gene expression by mRNA degradation or translational repression. Accumulated studies have demonstrated that miRs participate in various biological processes including cell differentiation, proliferation, apoptosis, metabolism and development, and the dysregulation of miRs expression are involved in different human diseases, such as neurological, cardiovascular disease and cancer. microRNA-503 (miR-503), one member of miR-16 family, has been studied widely in cardiovascular disease and cancer. In this review, we summarize and discuss the studies of miR-503 in vitro and in vivo, and how miR-503 regulates gene expression from different aspects of pathological processes of diseases, including carcinogenesis, angiogenesis, tissue fibrosis and oxidative stress; We will also discuss the mechanisms of dysregulation of miR-503, and whether miR-503 could be applied as a diagnostic marker or therapeutic target in cardiovascular disease or cancer.

Deficiency of telomere-associated repressor activator protein 1 precipitates cardiac aging in mice via p53/PPARα signaling

Background: Telomere shortening and dysfunction may cause metabolic disorders, tissue damage and age-dependent pathologies. However, little is known about the association of telomere-associated protein Rap1 with mitochondrial energy metabolism and cardiac aging. Methods: Echocardiography was performed to detect cardiac structure and function in Rap1^+/+ and Rap1^-/- mice at different ages (3 months, 12 months and 20 months). Telomere length, DNA damage, cardiac senescence and cardiomyocyte size were analyzed using the real-time PCR, Western blotting, senescence associated β-galactosidase assay and wheat germ agglutinin staining, respectively. Western blotting was also used to determine the level of cardiac fatty acid metabolism related key enzymes in mouse and human myocardium. Chromatin immunoprecipitation assay was used to verify the direct link between p53 and PPARα. The p53 inhibitor, Pifithrin-α and PPARα activator WY14643 were utilized to identify the effects of Rap1/p53/PPARα signaling pathway. Results: Telomere was shortened concomitant with extensive DNA damage in aged Rap1^-/- mouse hearts, evidenced by reduced T/S ratios and increased nuclear γH2AX. Meanwhile, the aging-associated phenotypes were pronounced as reflected by altered mitochondrial ultrastructure, enhanced senescence, cardiac hypertrophy and dysfunction. Mechanistically, acetylated p53 and nuclear p53 was enhanced in the Rap1^-/- mouse hearts, concomitant with reduced PPARα. Importantly, p53 directly binds to the promoter of PPARα in mouse hearts and suppresses the transcription of PPARα. In addition, aged Rap1^-/- mice exhibited reduced cardiac fatty acid metabolism. Pifithrin-α alleviated cardiac aging and enhanced fatty acid metabolism in the aged Rap1^-/- mice. Activating PPARα with WY14643 in primarily cultured Rap1^-/- cardiomyocytes restored maximal oxygen consumption rates. Reduced Rap1 expression and impaired p53/PPARα signaling also presented in aged human myocardium. Conclusion: In summary, Rap1 may link telomere biology to fatty acid metabolism and aging-related cardiac pathologies via modulating the p53/PPARα signaling pathway, which could represent a therapeutic target in preventing/attenuating cardiac aging.

Exosomal LINC00174 derived from vascular endothelial cells attenuates myocardial I/R injury via p53-mediated autophagy and apoptosis

In this study, we aim to investigate the regulation of specific long non-coding RNAs (lncRNAs) on the progression of ischemia/reperfusion (I/R) injury. We identified and characterized the exosomes derived from mouse primary aortic endothelial cells. Subsequently, we found that these exosomes expressed typical exosomal markers and high levels of LINC00174, which significantly ameliorated I/R-induced myocardial damage and suppressed the apoptosis, vacuolation, and autophagy of myocardial cells. Mechanistic approaches revealed that LINC00174 directly interacted with SRSF1 to suppress the expression of p53, thus restraining the transcription of myocardin and repressing the activation of the Akt/AMPK pathway that was crucial for autophagy initiation in I/R-induced myocardial damage. Moreover, this molecular mechanism was verified by in vivo study. In summary, exosomal LINC00174 generated from vascular endothelial cells repressed p53-mediated autophagy and apoptosis to mitigate I/R-induced myocardial damage, suggesting that targeting LINC00174 may be a novel strategy to treat I/R-induced myocardial infarction.

Hypoxic naked mole-rat brains use microRNA to coordinate hypometabolic fuels and neuroprotective defenses

Naked mole-rats are among the mammalian champions of hypoxia tolerance. They evolved adaptations centered around reducing metabolic rate to overcome the challenges experienced in their underground burrows. In this study, we used next-generation sequencing to investigate one of the factors likely supporting hypoxia tolerance in naked mole-rat brains, posttranscriptional microRNAs (miRNAs). Of the 212 conserved miRNAs identified using small RNA sequencing, 18 displayed significant differential expression during hypoxia. Bioinformatic enrichment revealed that hypoxia-mediated miRNAs were suppressing energy expensive processes including de novo protein translation and cellular proliferation. This suppression occurred alongside the activation of neuroprotective and neuroinflammatory pathways, and the induction of central signal transduction pathways including HIF-1α and NFκB via miR-335, miR-101, and miR-155. MiRNAs also coordinated anaerobic glycolytic fuel sources, where hypoxia-upregulated miR-365 likely suppressed protein levels of ketohexokinase, the enzyme responsible for catalyzing the first committed step of fructose catabolism. This was further supported by a hypoxia-mediated reduction in glucose transporter 5 proteins that import fructose into the cell. Yet, messenger RNA and protein levels of lactate dehydrogenase, which converts pyruvate to lactate in the absence of oxygen, were elevated during hypoxia. Together, this demonstrated the induction of anaerobic glycolysis despite a lack of reliance on fructose as the primary fuel source, suggesting that hypoxic brains are metabolically different than anoxic naked mole-rat brains that were previously found to shift to fructose-based glycolysis. Our findings contribute to the growing body of oxygen-responsive miRNAs "OxymiRs" that facilitate natural miRNA-mediated mechanisms for successful hypoxic exposures.

Activation of autophagy inhibits nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome activation and attenuates myocardial ischemia-reperfusion injury in diabetic rats

AIMS/INTRODUCTION

Diabetic hearts are more vulnerable to ischemia-reperfusion injury (I/RI). The activation of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome can mediate the inflammatory process, and hence might contribute to myocardial I/RI. Activation of autophagy can eliminate excess reactive oxygen species and alleviate myocardial I/RI in diabetes. The present study aimed to investigate whether the activation of autophagy can alleviate diabetic myocardial I/RI through inhibition of NLRP3 inflammasome activation.

MATERIALS AND METHODS

A dose of 65 mg/kg streptozotocin was given by tail vein injection to establish a type 1 diabetes model in the rats. The left anterior descending coronary artery was ligated for 30 min followed by reperfusion for 2 h to establish a myocardial I/RI model. H9C2 cardiomyocytes were exposed to high glucose (33 mmol/L) and subjected to hypoxia-reoxygenation (6 h hypoxia followed by 4 h reoxygenation).

RESULTS

The diabetic rats showed significant inhibition of cardiac autophagy (decreased LC3-II/I and increased p62) that was concomitant with increased activation of NLRP3 inflammasome (increased NLRP3, apoptosis-related spots protein cleaved caspase-1, interleukin-18, interleukin-1β) and more severe myocardial I/RI (elevated creatine kinase myocardial band, lactate dehydrogenase and larger infarct size). However, administration of rapamycin, an inhibitor of the autophagy, to activate autophagy resulted in the inhibition of NLRP3 inflammasome, and finally alleviated myocardial I/RI. In vitro, high glucose inhibited autophagy, while activating NLRP3 inflammasome in H9C2 cardiomyocytes and aggravating hypoxia-reoxygenation injury, but rapamycin reversed these adverse effects of high glucose.

CONCLUSION

Activation of autophagy can suppress the formation of NLRP3 inflammasome, which in turn attenuates myocardial ischemia-reperfusion injury in diabetic rats.

Protective effects of dexmedetomidine on hypoxia/reoxygenation injury in cardiomyocytes by regulating the CHOP signaling pathway

Hypoxia/reoxygenation (H/R) injury in myocardial cells occurs frequently during cardiac surgery and affects the prognosis of patients. The present study aimed to investigate the protective effects of dexmedetomidine (Dex) on H/R injury and its association with the C/EBP-homologous protein (CHOP) signaling pathway. An H/R model was constructed in H9C2 cells to investigate the effects of Dex on H/R injury. Cell viability, apoptosis and lactate dehydrogenase (LDH) levels were determined by MTT, flow cytometry and 2,4-dinitrophenylhydrazine colorimetric assays, respectively. The expression levels of inflammatory factors were measured by reverse transcription-quantitative PCR (RT-qPCR), and CHOP and glucose-regulated protein-78 (Grp78) expression levels were detected by RT-qPCR and western blotting. CHOP was overexpressed or knocked down to detect the cell viability, apoptosis, LDH level and the expression levels of inflammatory factors and Grp78. The results demonstrated that in the H/R group, cell viability was lower and apoptosis was higher, and that higher levels of LDH and inflammatory factors were present compared with those in the Dex+H/R group. Silencing of CHOP significantly reversed the H/R-reduced cell viability, high apoptotic rate and LDH levels, as well as the elevated expression levels of inflammatory factors and Grp78 caused by H/R injury, whereas the overexpression of CHOP inhibited cell viability and promoted apoptosis, elevated LDH level and expression of inflammatory factors and Grp78 compared with the negative control. Additionally, pretreatment with Dex significantly alleviated the H/R injury; thus, Dex may protect H9C2 cells against H/R induced cell injury, possibly by suppressing the CHOP signaling pathway.

MiR-181c-5p Promotes Inflammatory Response during Hypoxia/Reoxygenation Injury by Downregulating Protein Tyrosine Phosphatase Nonreceptor Type 4 in H9C2 Cardiomyocytes

Background

Constitutive nuclear factor kappa B (NFκB) activation has been shown to exacerbate during myocardial ischemia/reperfusion (I/R) injury. We recently showed that miR-181c-5p exacerbated cardiomyocytes injury and apoptosis by directly targeting the 3′-untranslated region of protein tyrosine phosphatase nonreceptor type 4 (PTPN4). However, whether miR-181c-5p mediates cardiac I/R injury through NFκB-mediated inflammation is unknown. Thus, the present study aimed to investigate the role of miR-181c-5p during myocardial I/R injury and explore its mechanism in relation to inflammation in H9C2 cardiomyocytes.

Methods and Results

In hypoxia/reoxygenation (H/R, 6 h hypoxia followed by 6 h reoxygenation)-stimulated H9C2 cardiomyocytes or postischemic myocardium of rat, the expression of miR-181c-5p was significantly upregulated, which was concomitant increased NFκB activity when compared to the nonhypoxic or nonischemic control groups. This is indicative that miR-181c-5p may be involved in NFκB-mediated inflammation during myocardial I/R injury. To investigate the potential role of miR-181c-5p in H/R-induced cell inflammation and injury, H9C2 cardiomyocytes were transfected with the miR-181c-5p agomir. Overexpression of miR-181c-5p significantly aggravated H/R-induced cell injury (increased lactate dehydrogenase (LDH) level) and exacerbated NFκB-mediated inflammation (greater phosphorylation and degradation of IκBα, phosphorylation of p65, and increased levels of proinflammatory cytokines tumor necrosis factor α (TNFα), interleukin (IL)-6, and IL-1β). In contrast, inhibition of miR-181c-5p by its antagomir transfection in vitro had the opposite effect. Furthermore, overexpression of miR-181c-5p significantly enhanced lipopolysaccharide-induced NFκB signalling. Additionally, knockdown of PTPN4, the direct target of miR-181c-5p, significantly aggravated H/R-induced phosphorylation and degradation of IκBα, phosphorylation of p65, and the levels of proinflammatory cytokines. PTPN4 knockdown also cancelled miR-181c-5p antagomir mediated anti-inflammatory effects in H9C2 cardiomyocytes during H/R injury.

Conclusions

It is concluded that miR-181c-5p may exacerbate myocardial I/R injury and NFκB-mediated inflammation via PTPN4, and that targeting miR-181c-5p/PTPN4/NFκB signalling may represent a novel strategy to combat myocardial I/R injury.

MicroRNAs in the regulation of cellular redox status and its implications in myocardial ischemia-reperfusion injury

MicroRNAs (miRNAs) are small RNAs that do not encode for proteins and play key roles in the regulation of gene expression. miRNAs are involved in a comprehensive range of biological processes such as cell cycle control, apoptosis, and several developmental and physiological processes. Oxidative stress can affect the expression levels of multiple miRNAs and, conversely, miRNAs may regulate the expression of redox sensors, alter critical components of the cellular antioxidants, interact with the proteasome, and affect DNA repair systems. The number of publications identifying redox-sensitive miRNAs has increased significantly over the last few years, and some miRNA targets such as Nrf2, SIRT1 and NF-κB have been identified. The complex interplay between miRNAs and ROS is discussed together with their role in myocardial ischemia-reperfusion injury and the potential use of circulating miRNAs as biomarkers of myocardial infarction. Detailed knowledge of redox-sensitive miRNAs is needed to be able to effectively use individual compounds or sets of miRNA-modulating compounds to improve the health-related outcomes associated with different diseases.

Light exercise without lactate elevation induces ischemic tolerance through the modulation of microRNA in the gerbil hippocampus

Previously we studied the possible neuroprotective effects of ischemia-resistant exercise in a gerbil model of transient whole-brain ischemia and evaluated the histology, expression of specific proteins, and brain function under different conditions. The present study investigated the neuroprotective effects of light exercise, without lactate elevation, in a gerbil model of ischemia/reperfusion injury. Transient whole-brain ischemia was induced by occlusion of the bilateral common carotid arteries for 5 min. A group of animals was subjected to treadmill exercise before ischemia induction. Hippocampal neuronal damage and miRNA expression, as well as behavioral deficits and plasma lactate levels, were evaluated. Light exercise suppressed hippocampal neuron loss and preserved short-term memory. Moreover, 14 miRNAs (mmu-miR-211-3p, -327, -451b, -711, -3070-3p, -3070-2-3p, -3097-5p, -3620-5p, -6240, -6916-5p, -6944-5p, 7083-5p, -7085-5p, and -7674-5p) were upregulated and 6 miRNAs (mmu-miR-148b-3p, -152-3p, -181c-5p, -299b-5p, -455-3p, and -664-3p) were downregulated due to ischemia. However, the expression of these miRNAs remained unchanged when animals performed light exercise before the ischemic event. Differentially expressed miRNAs regulate multiple biological processes such as inflammation, metabolism, and cell death. These findings suggest that light exercise reduces neuronal death and behavioral deficits after transient ischemia by regulating hippocampal miRNAs.

Overexpression of miR-375 Protects Cardiomyocyte Injury following Hypoxic-Reoxygenation Injury

The aim of the study was to evaluate the clinical significance of microRNA-375 in acute myocardial infarction patients and its mimic action in hypoxia/reoxygenation- (H/R-) induced ventricular cardiomyocyte H9c2 injury. In the current study, 90 ST-elevated acute MI patients (STEMI), 75 non-ST-elevated acute MI patients (NSTEMI), 90 healthy subjects, 14 weeks old mice, and ventricular cardiomyocyte H9c2 were included. The expressions of plasma microRNA-375 in patients with STEMI and NSTEMI and AMI mouse models were remarkably decreased than in controls (P < 0.001). The areas under the curve (AUC) of plasma microRNA-375 were revealed 0.939 in STEMI and 0.935 in NSTEMI subjects. Moreover, microRNA-375 levels in H/R-exposed cardiac H9c2 cells were evidently downregulated and significantly increased apoptosis rate and caspase-3 activity levels, while overexpression of miR-375 remarkably reduced apoptosis percentage and caspase-3 levels as compared with normal cells. Furthermore, this study also demonstrated that Nemo-like kinase (NLK), NLK mRNA, and protein expression levels were significantly downregulated in H/R-injured H9c2 cells, on the contrary, H9c2 cells transfected with mimic-miR-375 greatly upregulated NLK mRNA and protein expression. Plasma microRNA-375 may serve as an essential clinical biomarker for diagnosis of early-stage AMI. Mimic expression of miR-375 significantly prevented H/R-induced cardiomyocyte injury by decreasing caspase-3 activity through upregulation of the NLK gene, recommended as a new therapeutic option for AMI patient.

MicroRNA-181c provides neuroprotection in an intracerebral hemorrhage model

Apoptosis is an important factor during the early stage of intracerebral hemorrhage. MiR-181c plays a key regulatory role in apoptosis. However, whether miR-181c is involved in apoptosis of prophase cells after intracerebral hemorrhage remains unclear. Therefore, in vitro and in vivo experiments were conducted to test this hypothesis. In vivo experiments: collagenase type VII was injected into the basal ganglia of adult Sprague-Dawley rats to establish an intracerebral hemorrhage model. MiR-181c mimic or inhibitor was injected in situ 4 hours after intracerebral hemorrhage. Neurological functional defects (neurological severity scores) were assessed 1, 7, and 14 days after model establishment. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and western blot assay were conducted 14 days after model establishment. In vitro experiments: PC12 cells were cultured under oxygen-glucose deprivation, and hemins were added to simulate intracerebral hemorrhage in vitro. MiR-181c mimic or inhibitor was added to regulate miR-181c expression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, luciferase reporter system, and western blot assay were performed. Experimental results revealed differences in miR-181c expression in brain tissues of both patients and rats with cerebral hemorrhage. In addition, in vitro experiments found that miR-181c overexpression could upregulate the Bcl-2/Bax ratio to inhibit apoptosis, while inhibition of miR-181c expression could reduce the Bcl-2/Bax ratio and aggravate apoptosis of cells. Regulation of apoptosis occurred through the phosphoinositide 3 kinase (PI3K)/Akt pathway by targeting of phosphatase and tensin homolog deleted on chromosome ten (PTEN). Higher miR-181c overexpression correlated with lower neurological severity scores, indicating better recovery of neurological function. In conclusion, miR-181c affects the prognosis of intracerebral hemorrhage by regulating apoptosis, and these effects might be directly mediated and regulated by targeting of the PTEN\PI3K/Akt pathway and Bcl-2/Bax ratio. Furthermore, these results indicated that miR-181c played a neuroprotective role in intracerebral hemorrhage by regulating apoptosis of nerve cells, thus providing a potential target for the prevention and treatment of intracerebral hemorrhage. Testing of human serum was authorized by the Ethics Committee of China Medical University (No. 2012-38-1) on February 20, 2012. The protocol was registered with the Chinese Clinical Trial Registry (Registration No. ChiCTR-COC-17013559). The animal study was approved by the Institutional Animal Care and Use Committee of China Medical University (approval No. 2017008) on March 8, 2017.

MiR-149 Aggravates Pyroptosis in Myocardial Ischemia-Reperfusion Damage via Silencing FoxO3

BACKGROUND MicroRNAs (miRNAs), which modulate the expression of their target genes, are commonly involved in stimulating and adjusting of many processes that result in cardiovascular diseases, contain cardiac ischemia/reperfusion (I/R) damage. However, the expression and role of miR-149 in pyroptosis mediated myocardial I/R damage remains unclear. MATERIAL AND METHODS Real-time polymerase chain reaction was performed to measure the miR-149 and FoxO3 expression in I/R stimulated H9C2 cells. The cell proliferation, pyroptosis-related inflammatory genes in I/R-treated H9C2 cells transfected miR-149 mimics or miR-149 inhibitor were both explored. We predicted and confirmed miR-149 targets by using bioinformatics analyses and luciferase reporter assay. In addition, the potential relationship between miR-149 and FoxO3 in pyroptosis from I/R treated H9C2 cells was analyzed. RESULTS Our results showed that miR-149 was upregulated, while FoxO3 was downregulated in I/R stimulated H9C2 cells. Over-expression of miR-149 inhibited cell viability and promote pyroptosis, however, down-expression of miR-149 had an opposite effect in I/R treated H9C2 cells. Furthermore, miR-149 could negatively regulate FoxO3 expression by binding 3'UTR, whereas silencing of FoxO3 attenuated the effect of miR-149-mimics on cell proliferation and pyroptosis in I/R treated H9C2 cells. CONCLUSIONS Our study found that miR-149 played a critical role in pyroptosis during cardiac I/R injury, and thus, might provide a novel therapeutic target.