Mediated protective effect of electroacupuncture pretreatment by miR-214 on myocardial ischemia/reperfusion injury

Research Progress of Electrical Stimulation in Ischemic Heart Disease

Ischemic heart disease (IHD) is a considerable health burden worldwide with high mortality and morbidity. Treatments for IHD are mainly focused on decreasing oxygen demand or increasing myocardial oxygen supply, including pharmacological, interventional, and surgical treatment, but there are also some limitations. Therefore, it is important to find a simple, effective, and economical treatment. As non-invasive and safe physiotherapy, electrical stimulation (ES) has a promising application in the treatment of IHD. Current studies suggest that ES can affect the occurrence and development of IHD by promoting angiogenesis, regulating autophagy and apoptosis, inhibiting the inflammatory response and oxidative stress. In this review, we focus predominantly on the mechanism of ES and the current progress of ES therapy in IHD, furthermore, give a brief introduction to the forms of ES in clinical application.

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.

Advances in Research on the circRNA-miRNA-mRNA Network in Coronary Heart Disease Treated with Traditional Chinese Medicine

There has been an increase in morbidity and mortality related to coronary heart disease (CHD) in China in recent years. Numerous clinical experiences and studies have shown that traditional Chinese medicine (TCM) plays an important role in the prevention, treatment, and prognosis of CHD. However, the mechanism of TCM in the treatment of CHD has not yet been elucidated. The circRNA-miRNA-mRNA network consists of miRNA that is competitively bound by circRNA, and miRNA regulates the transcription level of mRNA. Through literature review, we found that the circRNA-miRNA-mRNA network acts to contribute to certain effects to CHD such as myocardial hypertrophy, myocardial fibrosis, and heart failure. TCM contains constituents that act against CHD by antiatherosclerosis and apoptosis inhibition action, cardiac and cardiomyocyte protection, and these components also promote cell growth and protection of the vascular system by regulating miRNAs. Therefore, we consider that the circRNA-miRNA-mRNA network may be a new regulatory mechanism for the effective treatment of CHD by TCM.

MicroRNA-214-5p protects against myocardial ischemia reperfusion injury through targeting the FAS ligand

INTRODUCTION

MicroRNAs (miRNAs) are considered as crucial modulators in myocardial ischemia and reperfusion (I/R) injury. The present study aimed to investigate the expression and biological functions of miR-214-5p via targeting Fas ligand (FASLG) in I/R injury.

MATERIAL AND METHODS

Lactate dehydrogenase, casein kinase, malondialdehyde assay, reactive oxygen species (ROS) detection and cell apoptosis analysis measured cell damage and cell apoptosis in H9c2 cells under hypoxia/reperfusion (H/R) treatment. Bioinformatics and dual luciferase reporter assays demonstrated the molecular mechanism of miR-214-5p in cardiac cells. 2,3,5-Triphenyltetrazolium chloride (TTC) staining, hematoxylin-eosin (HE) staining and adenovirus injection were performed in I/R treated mice.

RESULTS

The expression of miR-214-5p was decreased in H/R injured H9c2 cells compared with control cells (p < 0.001). Overexpression of miR-214-5p reduced cell damage and apoptosis in H9c2 cells under H/R treatment (p < 0.001). Further study revealed that FASLG was a target of miR-214-5p. Enhanced expression of FASLG attenuated the protective function of miR-214-5p in H9c2 cells subjected to H/R injury (P < 0.001). Moreover, the elevated expression of miR-214-5p by adenovirus injection protected cardiac cells from I/R injury in mice (n = 6/per group).

CONCLUSIONS

We found that miR-214-5p exerted a protective role in I/R injured cardiac cells by direct targeting FASLG in vitro and in vivo.

The Role of Adenosine A2b Receptor in Mediating the Cardioprotection of Electroacupuncture Pretreatment via Influencing Ca2+ Key Regulators

Objective

To investigate the roles played by A2b receptor and the key Ca²⁺ signaling components in the mediation of the cardioprotection of electroacupuncture pretreatment in the rats subjected to myocardial ischemia and reperfusion.

Methods

SD rats were randomly divided into a normal control (NC) group, ischemia/reperfusion model (M) group, electroacupuncture pretreatment (EA) group, and electroacupuncture pretreatment plus A2b antagonist (EAG) group. The ischemia/reperfusion model was made by ligation and loosening of the left descending branch of the coronary artery in all groups except the NC group. The EA group was pretreated with electroacupuncture at the Neiguan (PC6) point once a day for three consecutive days before the modeling. The elevation of the ST segment, arrhythmia scores, and myocardial infarction size of each group was measured. The relative expression levels of A2b, RyR2, SERCA2a, NCX1, P-PLB(S16)/PLB, and Troponin C/Troponin I proteins in the injured myocardium were detected by multiple fluorescence western blot.

Results

The level of ST segment, arrhythmia scores, and infarct size in the M group was significantly higher/larger than that in the NC group after ischemia and reperfusion, while all the three indices mentioned above in the EA group were significantly lower/smaller than those in the M group after reperfusion. The expression of the proteins of adenosine receptor 2b(A2b), ryanodine receptor 2(RyR2), and sarco(endo)plasmic reticulum Ca²⁺-ATPase 2a (SERCA2a) in the EA group was significantly enhanced as compared with the M group, while in the EAG group, the contents of A2b were significantly lower than those in the EA group, and RyR2 was higher in the EAG group. In comparison with the NC group, the relative expression of NCX1 protein in M, EA, and EAG groups was not changed significantly. The ratio of phosphorylated phospholamban (P-PLB) over phospholamban (PLB) in the M group was significantly lower than that in the NC group, and the ratio in the EA group was significantly increased as compared with the M group, while the ratio of Troponin C/Troponin I in the EA group was significantly decreased in comparison with that in other groups.

Conclusion

Electroacupuncture pretreatment could reduce ischemia and reperfusion-induced myocardial injury via possibly increasing the A2b content and regulating the key Ca²⁺ signaling components, namely inhibiting RyR2 and enhancing P-PLB(S16)/PLB ratio and SERCA2a proteins, so as to diminish the intracellular Ca²⁺ overload and consequently lessen the myocardial injury.

MicroRNA in Acupuncture Studies: Does Small RNA Shed Light on the Biological Mechanism of Acupuncture?

MicroRNAs (miRNAs) are the main regulators of diverse physiological processes. Recently, miRNAs have emerged as significant players related to the effect of acupuncture although the biological mechanisms connecting the function of these miRNAs with the effect of acupuncture are not well understood. In animal models of various diseases, such as neurological disease, cardiovascular disease, myopathy, and pain, a number of miRNAs were altered after administration of electroacupuncture or manual acupuncture. Nonetheless, there are a limited number of studies published so far. This paper reviewed and discussed whether miRNAs could elucidate potential biological mechanism of acupuncture in the future studies.

miR-214 Down-Regulation Promoted Hypoxia/Reoxygenation-Induced Hepatocyte Apoptosis Through TRAF1/ASK1/JNK Pathway

OBJECTIVE

This study investigated the role of miR-214 in the hepatocyte apoptosis induced by hypoxia/reoxygenation (H/R) injury.

MATERIALS AND METHODS

In vivo hepatic ischemia/reperfusion (HIR) injury, mice model and in vitro HR model were established. miR-214, TRAF1, ASK1, and JNK expression levels were detected by qRT-PCR and western blot. The apoptosis of mouse hepatocyte AML12 was detected by flow cytometry analysis. The interaction between miR-214 and TRAF1 was confirmed by dual-luciferase reporter gene assay.

RESULTS

Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were elevated in HIR injury mice compared with sham mice. miR-214 expression was down-regulated in liver tissues of HIR and H/R-induced hepatocytes, whereas TRAF1, ASK1, and JNK expressions were up-regulated in HIR and H/R groups. H/R stimulation promoted the apoptosis of hepatocytes, and miR-214 overexpression inhibited the apoptosis of hepatocytes. Besides, TRAF1 was a target of miR-214 and negatively regulated by miR-214. miR-214/TRAF1 pathway involved in the modulation of H/R-induced apoptosis of hepatocytes. In vivo study proved miR-214 reduced hepatic injury of HIR mice.

CONCLUSION

miR-214 overexpression reduces hepatocyte apoptosis after HIR injury through negatively regulating TRAF1/ASK1/JNK pathway.

miR-424 promotes cardiac ischemia/reperfusion injury by direct targeting of CRISPLD2 and regulating cardiomyocyte pyroptosis

As a complex pathophysiological event, myocardial ischemia/reperfusion injury (IRI) can cause heart failure, which has been associated with pyroptosis, a pro-inflammatory programmed cell death. Small endogenous non-coding RNAs have been shown to be involved in myocardial IRI. In the present study, we aimed to investigate whether miR-424 modulated pyroptosis in response to myocardial IRI and determine its underlying regulatory mechanism. An in vivo mouse model of cardiac IRI was established, and contractile function was evaluated by echography. The serum and heart tissue were harvested 24 h after reperfusion to assess the status of pyroptosis. For the in vitro study, H9C2 cells (a rat heart cell line) were subjected to 6 h of hypoxia, followed by 18 h of reoxygenation. The gene expressions at the mRNA level were assessed by real-time PCR, and the expressions at the protein level were examined by western blotting, immunofluorescence staining, and enzyme-linked immunosorbent assay (ELISA). Bioinformatic analysis was applied to predict miR-424 targets, which were then confirmed by a luciferase reporter assay. We found that the expressions of pyroptosis-related proteins, including caspase-1, caspase-11, IL-1β, and IL-18, were significantly increased upon myocardial IRI. Similarly, hypoxia/reoxygenation injury (HRI) also induced pyroptosis in H9C2 cells. Furthermore, our study revealed that the miR-424 expression was substantially increased in I/R heart tissue and H/R-challenged H9C2 cells. In addition, we found that exogenous expression of miR-424 directly targeted cysteine-rich secretory protein LCCL domain-containing 2 (CRISPLD2) and up-regulated the expressions of caspase-1 and the pro-inflammatory cytokines IL-1β and IL-18. Taken together, our findings provided a new signaling pathway of miR-424/CRISPLD2 in cardiac pyroptosis under IRI conditions.

Electroacupuncture Alleviates Surgical Trauma-Induced Hypothalamus Pituitary Adrenal Axis Hyperactivity Via microRNA-142

Electroacupuncture (EA) could improve the hyperactivity of the hypothalamus pituitary adrenal (HPA) axis induced by hepatectomy. However, its underlying mechanism still remains largely unclear. Here, we found that hypothalamic corticotrophin releasing hormone (CRH) modulates the function of the HPA axis, while hepatectomy induced an HPA axis disorder and EA application could regulate the hypothalamic CRH. We first demonstrated that microRNAs (miRNAs) target on CRH via bioinformatics analysis and screened them in the primary hypothalamic neurons. MicroR-142 (miR-142) and miR-376c were identified to inhibit CRH at the mRNA and protein levels, and a dual luciferase reporter assay confirmed their binding to the 3'-untranslated regions (3'-UTR) of CRH. Further analyses revealed a decrease in hypothalamic miR-142 expression in the hepatectomy rats and an increase in miR-142 and miR-376c after EA intervention. Importantly, the improvement effect of EA on the HPA axis regulatory function in hepatectomy rats was blocked by miR-142 antagomir. Our findings illustrated that EA could up-regulate hypothalamic miR-142 expression and decrease the CRH level to alleviate the hyperactivity of the HPA axis induced by hepatectomy.

Cardioprotective Effect of Electroacupuncture Pretreatment on Myocardial Ischemia/Reperfusion Injury via Antiapoptotic Signaling

Objectives. Our previous study has used RNA-seq technology to show that apoptotic molecules were involved in the myocardial protection of electroacupuncture pretreatment (EAP) on the ischemia/reperfusion (I/R) animal model. Therefore, this study was designed to investigate how EAP protects myocardium against myocardial I/R injury through antiapoptotic mechanism. Methods. By using rats with myocardial I/R, we ligated the left anterior descending artery (LAD) for 30 minutes followed by 4 hr of reperfusion after EAP at the Neiguan (PC6) acupoint for 12 days; we employed arrhythmia scores, serum myocardial enzymes, and cardiac troponin T (cTnT) to evaluate the cardioprotective effect. Heart tissues were harvested for western blot analyses for the expressions of pro- and antiapoptotic signaling molecules. Results. Our preliminary findings showed that EAP increased the survival of the animals along with declined arrhythmia scores and decreased CK, LDH, CK-Mb, and cTnT levels. Further analyses with the heart tissues detected reduced myocardial fiber damage, decreased number of apoptotic cells and the protein expressions of Cyt c and cleaved caspase 3, and the elevated level of Endo G and AIF after EAP intervention. At the same time, the protein expressions of antiapoptotic molecules, including Xiap, BclxL, and Bcl2, were obviously increased. Conclusions. The present study suggested that EAP protected the myocardium from I/R injury at least partially through the activation of endogenous antiapoptotic signaling.

Transcriptomic Analysis of Myocardial Ischemia Using the Blood of Rat

Myocardial ischemia is a pathological state of heart with reduced blood flow to heart and abnormal myocardial energy metabolism. This disease occurs commonly in middle aged and elderly people. Several studies have indicated that the rat was an appropriate animal model used to study myocardial ischemia. In this study, in order to gain insights into the pathogenesis of myocardial ischemia, we sequenced the transcriptomes of three normal rats as control and the same number of myocardial ischemia rats. We sequenced the genomes of 6 rats, including 3 cases (myocardial ischemia) and 3 controls using Illumina HiSeq 2000. Then we calculated the gene expression values and identified differentially expressed genes based on reads per kilobase transcriptome per million (RPKM). Meanwhile we performed a GO enrichment analysis and predicted novel transcripts. In our study, we found that 707 genes were up-regulated and 21 genes were down-regulated in myocardial ischemia rats by at least 2-fold compared with controls. By the distribution of reads and the annotation of reference genes, we found 1,703 and 1,552 novel transcripts in cases and controls, respectively. At the same time, we refined the structure of 9,587 genes in controls and 10,301 in cases. According to the results of GO term and pathway analysis of differentially expressed genes, we found that the immune response, stimulus response, response to stress and some diseases may be associated with myocardial ischemia. Since many diseases, especially immune diseases, are associated with myocardial ischemia, we should pay more attention to the complications which might result from myocardial ischemia.