Expression of miRNA-214 in the sera of elderly patients with acute myocardial infarction and its effect on cardiomyocyte apoptosis

Research Progress of Aging-related MicroRNAs

Senescence refers to the irreversible state in which cells enter cell cycle arrest due to internal or external stimuli. The accumulation of senescent cells can lead to many age-related diseases, such as neurodegenerative diseases, cardiovascular diseases, and cancers. MicroRNAs are short non-coding RNAs that bind to target mRNA to regulate gene expression after transcription and play an important regulatory role in the aging process. From nematodes to humans, a variety of miRNAs have been confirmed to alter and affect the aging process. Studying the regulatory mechanisms of miRNAs in aging can further deepen our understanding of cell and body aging and provide a new perspective for the diagnosis and treatment of aging-related diseases. In this review, we illustrate the current research status of miRNAs in aging and discuss the possible prospects for clinical applications of targeting miRNAs in senile diseases.

Exosomal miR‑152‑5p/ARHGAP6/ROCK axis regulates apoptosis and fibrosis in cardiomyocytes

Acute myocardial infarction (AMI) is a fatal cardiovascular disease with a high mortality rate. The discovery of effective biomarkers is crucial for the diagnosis and treatment of AMI. In the present study, miRNA sequencing and reverse transcription-quantitative polymerase chain reaction techniques revealed that the expression of exosome derived miR-152-5p was significantly downregulated in patients with AMI compared with healthy controls. A series of functional validation experiments were then performed using H9c2 cardiomyocytes. Following transfection of the cardiomyocytes using an miR-152-5p inhibitor, immunofluorescence staining of a-smooth muscle actin revealed a marked increase in fibrosis. Western blotting revealed that the expression levels of the apoptotic protein Bax, TNF-α and collagen-associated proteins were significantly increased, whereas those of the apoptosis-inhibiting factor Bcl-2 and vascular endothelial growth factor A were significantly decreased. Furthermore, the binding of Rho GTPase-activating protein 6 (ARHGAP6) to miR-152-5p was predicted using an online database and verified using a dual-luciferase reporter gene assay. The transfection of cardiomyocytes with miR-152-5p mimics was found to inhibit the activation of ARHGAP6 and Rho-associated coiled-coil containing kinase 2 (ROCK2). These results suggest that miR-152-5p targets ARHGAP6 through the ROCK signaling pathway to inhibit AMI, which implies that miR-152-5p may be a diagnostic indicator and potential target for treatment of myocardial infarction.

Prognostic value of circulating microRNA-21-5p and microRNA-126 in patients with acute myocardial infarction and infarct-related artery total occlusion

Background

Cardiovascular disease, including acute myocardial infarction (AMI), is a major global cause of mortality and morbidity. Specificity and sensitivity limit the utility of classic diagnostic biomarkers for AMI. Therefore, it is critical to identify novel biomarkers for its accurate diagnosis. Cumulative studies have demonstrated that circulating microRNAs (miRs) participate in the pathophysiological processes of AMI and are promising diagnostic biomarkers for the condition. This study aimed to ascertain the diagnostic accuracy of circulating miR-21-5p and miR-126 used as biomarkers in patients with AMI and infarct-related artery total occlusion (IR-ATO) or infarct-related blood-vessel recanalization (IR-BVR).

Methods

The expression of miR-21-5p and miR-126 was examined separately in 50 healthy subjects, 51 patients with IR-ATO AMI, and 49 patients with IR-BVR AMI using quantitative real-time polymerase chain reaction.

Results

When compared with the control group, the IR-ATO AMI group exhibited increased miR-21-5p (p < 0.0001) and miR-126 (p < 0.0001), and the IR-BVR AMI group exhibited increased miR-21-5p (p < 0.0001). However, there was no significant difference in miR-126 between the IR-BVR AMI and the control groups. A Spearman's correlation coefficient showed a strong correlation was found between miR-21-5p, miR-126, cardiac troponin-I, and creatine kinase isoenzyme in all three groups, while a receiver operating characteristic analysis revealed that miR-21-5p and miR-126 exhibited considerable diagnostic accuracy for IR-ATO AMI.

Conclusion

Circulating miR-21-5p and miR-126 may be promising prognostic biomarkers for patients with AMI and IR-ATO.

The Role of Mitochondrial miRNAs in the Development of Radon-Induced Lung Cancer

MicroRNAs are short, non-coding RNA molecules regulating gene expression by inhibiting the translation of messenger RNA (mRNA) or leading to degradation. The miRNAs are encoded in the nuclear genome and exported to the cytosol. However, miRNAs have been found in mitochondria and are probably derived from mitochondrial DNA. These miRNAs are able to directly regulate mitochondrial genes and mitochondrial activity. Mitochondrial dysfunction is the cause of many diseases, including cancer. In this review, we consider the role of mitochondrial miRNAs in the pathogenesis of lung cancer with particular reference to radon exposure.

LncRNA HOTTIP Knockdown Attenuates Acute Myocardial Infarction via Regulating miR-92a-2/c-Met Axis

Increasing investigations have focused on long non-coding RNAs (lncRNAs) in various human diseases, including acute myocardial infarction (AMI). Although lncRNA HOTTIP has been identified to play an important role in coronary artery diseases, its role and specific mechanism in AMI remain unclear. To investigate the potential role of HOTTIP in MI, HOTTIP expression in hypoxia-treated cardiomyocytes and myocardial tissues of MI mice was evaluated. The potential targets of HOTTIP and miR-92a-2 were predicted using Starbase and Targetscan. To further determine the cardio-protective effects of HOTTIP in vivo, si-HOTTIP and miR-92a-2 mimics were individually or co-injected into mice through intramyocardial injection. Moreover, their roles were further confirmed in rescue experiments. HOTTIP was significantly upregulated in ischemic myocardium of MI mice and hypoxia-induced cardiomyocytes. Moreover, HOTTIP knockdown markedly promoted cardiomyocyte growth and inhibited cardiomyocyte apoptosis in vitro. Luciferase reporter assay showed that HOTTIP could directly sponge miR-92a-2 to negatively regulate miR-92a-2 expression. In addition, c-Met was identified as a direct target of miR-92a-2, and their correlation was confirmed by luciferase reporter assay. MiR-92a-2 overexpression significantly enhanced the protective effect of HOTTIP knockdown against AMI through partially inhibiting c-Met expression. Our results demonstrated that HOTTIP downregulation attenuated AMI progression via the targeting miR-92a-2/c-Met axis and suggested that HOTTIP might be a potential therapeutic target for AMI.

miR-124 promotes apoptosis and inhibits the proliferation of vessel endothelial cells through P38/MAPK and PI3K/AKT pathways, making it a potential mechanism of vessel endothelial injury in acute myocardial infarction

Due to its rapid onset and high rates of fatality, acute myocardial infarction (AMI) has long been one of the most fatal diseases among all types of heart diseases. Therefore, intensive research efforts have been focused on understanding AMI's potential pathogenesis to seek effective treatment options. In the present study, 20 peripheral blood samples were collected from patients with AMI, after which reverse transcription-quantitative PCR analysis revealed that microRNA (miR)-124 levels in the peripheral blood of patients with AMI was significantly elevated compared with that in the control group. In vitro, a model using pcDNA3.1-miR-124 transfected human umbilical vein endothelial cells (HUVECs) indicated that overexpression of miR-124 could significantly promote the apoptosis and suppress the proliferation of HUVECs using flow cytometry, TUNEL assay and Cell Counting Kit-8 assays. Based on the present findings, RNA samples of HUVECs overexpressing miR-124 was extracted and sequenced to explore the gene expression profile after miR-124 overexpression. Gene Set Enrichment Analysis (GSEA) analysis revealed that the downregulated genes were mainly enriched in signaling pathways, such as PI3K-AKT, whilst the upregulated genes were mainly enriched in metabolism-related signaling pathways, such as the metabolism of xenobiotics by cytochrome P450 pathway. Additionally, Rideogram software was used to determine the chromosomal localization of the differentially expressed genes. The results demonstrated that they were distributed on all chromosomes except for chromosome Y. In addition, characteristic profiles of the differentially expressed genes caused by miR-124 overexpression were analyzed using Connectivity Map. In total, two medicines, anisomycin and sanguinarine, which function as p38/MAPK signaling agonists that can inhibit angiogenesis, presented with the highest enrichment scores. Together with the GSEA results, which indicated that the differentially expressed genes were mainly enriched in the angiogenesis-inhibiting PI3K/AKT signaling pathway, the present study reported that high expression of miR-124 was negatively associated with patients with AMI, promoting the apoptosis and suppressing the proliferation of vessel endothelial cells.

The protective role of MiR-206 in regulating cardiomyocytes apoptosis induced by ischemic injury by targeting PTP1B

MicroRNAs play essential roles in the regulation and pathophysiology of acute myocardial infarction (AMI). The purpose of the present study was to assess the expression signature of miR-206 in rat heart with AMI and the corresponding molecular mechanism. The expression of miR-206 significantly decreased in the infarcted myocardial areas and in hypoxia-induced cardiomyocytes, compared with that in the noninfarcted areas. Overexpression of miR-206 decreased cardiomyocytes apoptosis and the down-regulation of miR-206 increased cardiomyocytes apoptosis in vitro. In addition, overexpression of miR-206 in rat heart in vivo remarkably reduced myocardial infarct size and cardiomyocytes apoptosis. We identified that miR-206 had a protective effect on cardiomyocytes apoptosis with the association of its target protein tyrosine phosphatase 1B (PTP1B). Gain-of-function of miR-206 inhibited PTP1B expression and loss-of-function of miR-206 up-regulated PTP1B expression. Furthermore, overexpression of PTP1B significantly increased cardiomyocytes apoptosis. These results together suggest the protective effect of miR-206 against cardiomyocytes apoptosis induced by AMI by targeting PTP1B.

MiR-29b-3p aggravates cardiac hypoxia/reoxygenation injury via targeting PTX3

Our current research aimed to decipher the role and underlying mechanism with regard to miR-29b-3p involving in myocardial ischemia/reperfusion (I/R) injury. In the present study, cardiomyocyte H9c2 cell was used, and hypoxia/reoxygenation (H/R) model was established to mimic the myocardial I/R injury. The expressions of miR-29b-3p and pentraxin 3 (PTX3) were quantified deploying qRT-PCR and Western blot, respectively. The levels of LDH, TNF-α, IL-1β and IL-6 were detected to evaluate cardiomyocyte apoptosis and inflammatory response. Cardiomyocyte viability and apoptosis were examined employing CCK-8 assay and flow cytometry, respectively. Verification of the targeting relationship between miR-29b-3p and PTX3 was conducted using a dual-luciferase reporter gene assay. It was found that miR-29b-3p expression in H9c2 cells was up-regulated by H/R, and a remarkable down-regulation of PTX3 expression was demonstrated. MiR-29b-3p significantly promoted of release of inflammatory cytokines of H9c2 cells, and it also constrained the proliferation and promoted the apoptosis of H9c2 cells. Additionally, PTX3 was inhibited by miR-29b-3p at both mRNA and protein levels, and it was identified as a direct target of miR-29b-3p. PTX3 overexpression could reduce the inflammatory response, increase the viability of H9c2 cells, and inhibit apoptosis. Additionally, PTX3 counteracted the function of miR-29b-3p during the injury of H9c2 cells induced by H/R. In summary, miR-29b-3p was capable of aggravating the H/R injury of H9c2 cells by repressing the expression of PTX3.

miR-214 Protects Against Uric Acid-Induced Endothelial Cell Apoptosis

Background: Uric acid (UA) has been reported to be an important risk factor for cardiovascular diseases and can cause endothelial cell apoptosis through unclear mechanisms. Accumulating evidence has demonstrated that miR-214 plays a pivotal role in the pathogenesis of cardiovascular diseases. This study was to investigate the role of miR-214 in UA-induced endothelial cell apoptosis and the underlying mechanism.

Material and methods: We enrolled 30 patients with hyperuricemia and 32 healthy controls and analyzed the levels of miR-214 in the serum of the participants. Then mouse aorta endothelial cells (MAECs) were treated with UA to induce cell apoptosis. An miR-214 mimic and a specific COX-2 inhibitor (NS398) were used to confirm the roles of these molecules in mediating UA-induced MAEC apoptosis or COX-2/PGE₂ cascade activation.

Results: A significant reduction in circulating miR-214 in the hyperuricemia patients compared with the healthy controls, along with a negative correlation with UA levels was observed. In the MAECs, UA treatment strikingly increased apoptosis as shown by the upregulation of BAX and cleaved Caspase-3 and the increased number of apoptotic cells. Interestingly, the expression of COX-2 was also upregulated at both the protein and mRNA levels during UA-induced cell apoptosis. In addition, an miR-214 mimic blocked UA-induced MAEC apoptosis, COX-2 induction and PGE₂ secretion. The inhibition of COX-2 markedly ameliorated UA-induced apoptotic response and PGE₂ production in MAECs. Luciferase activity assays further confirmed that COX-2 is a target gene of miR-214 in endothelial cells.

Conclusion: We concluded that miR-214 could alleviate UA-induced MAEC apoptosis possibly by inhibiting the COX-2/PGE₂ cascade.

Inhibition of miR-193a-3p protects human umbilical vein endothelial cells against intermittent hypoxia-induced endothelial injury by targeting FAIM2

OBJECTIVE

The functions and molecular regulatory mechanisms of miR-193a-3p in cardiac injury induced by obstructive sleep apnea (OSA) are poorly understood. This study aimed to explore the role of miR-193a-3p in intermittent hypoxia(IH)-induced human umbilical vein endothelial cells (HUVECs) injury.

RESULTS

In this study, we found that IH significantly decreased viability but enhanced cell apoptosis. Concurrently, the miR-193a-3p expression level was increased in HUVECs after IH. Subsequent experiments showed that IH-induced injury was ameliorated through miR-193a-3p silence. Fas apoptotic inhibitory molecule 2 (FAIM2) was predicted by bioinformatics analysis and further identified as a direct target gene of miR-193a-3p. Interestingly, the effect of miR-193a-3p inhibition under IH could be reversed by down-regulating FAIM2 expression.

CONCLUSION

In conclusion, our study first revealed that miR-193a-3p inhibition could protect HUVECs against intermittent hypoxia-induced damage by negatively regulating FAIM2. These findings could advance our understanding of the underlying mechanisms for OSA-related cardiac injury.

METHODS

We exposed HUVECs to IH condition; the expression levels of miR-193a-3p were detected by RT-qPCR. Cell viability, and the expressions of apoptosis-associated proteins were examined via CCK-8, and western blotting, respectively. Target genes of miR-193a-3p were confirmed by dual-luciferase reporter assay.