Impaired regulation of MMP2/16-MLCK3 by miR-146a-5p increased susceptibility to myocardial ischemic injury in aging mice

Epigenetic modifications and emerging therapeutic targets in cardiovascular aging and diseases

The complex mechanisms underlying the development of cardiovascular diseases remain not fully elucidated. Epigenetics, which modulates gene expression without DNA sequence changes, is shedding light on these mechanisms and their heritable effects. This review focus on epigenetic regulation in cardiovascular aging and diseases, detailing specific epigenetic enzymes such as DNA methyltransferases (DNMTs), histone acetyltransferases (HATs), and histone deacetylases (HDACs), which serve as writers or erasers that modify the epigenetic landscape. We also discuss the readers of these modifications, such as the 5-methylcytosine binding domain proteins, and the erasers ten-eleven translocation (TET) proteins. The emerging role of RNA methylation, particularly N6-methyladenosine (m6A), in cardiovascular pathogenesis is also discussed. We summarize potential therapeutic targets, such as key enzymes and their inhibitors, including DNMT inhibitors like 5-azacytidine and decitabine, HDAC inhibitors like belinostat and givinotide, some of which have been approved by the FDA for various malignancies, suggesting their potential in treating cardiovascular diseases. Furthermore, we highlight the role of novel histone modifications and their associated enzymes, which are emerging as potential therapeutic targets in cardiovascular diseases. Thus, by incorporating the recent studies involving patients with cardiovascular aging and diseases, we aim to provide a more detailed and updated review that reflects the advancements in the field of epigenetic modification in cardiovascular diseases.

Impact of microRNAs on cardiovascular diseases and aging

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality for both men and women among all ethnicities worldwide. Although significant improvements in the management of CVD occurred in the 20th century, non-invasive, universal, early diagnostic biomarkers and newer therapeutic drugs are needed for clinical treatment by physicians. MicroRNAs (miRNAs) are a class of endogenous, non-coding, single-stranded, small RNA molecules that are critically controlled by all human biological processes. Moreover, dysregulated miRNA expression is directly involved in various CVDs, including stable coronary artery disease and acute coronary syndrome. Several miRNAs that are enriched in the plasma of CVD patients have potential as clinical biomarkers, and overexpression or inhibition of specific miRNAs has novel therapeutic significance in the management of CVD. Aging is a multifactorial physiological process that gradually deteriorates tissue and organ function and is considered a non-modifiable major risk factor for CVDs. Recently, several studies established that various miRNAs essentially regulate aging and aging-related disease processes. This narrative review briefly discusses the recently updated molecular involvement of miRNAs in CVDs, their possible diagnostic, prognostic, and therapeutic value, and their relationship to the aging process.

The investigation of potential mechanism of Fuzhengkangfu Decoction against Diabetic myocardial injury based on a combined strategy of network pharmacology, transcriptomics, and experimental verification

BACKGROUND AND OBJECTIVES

Diabetic cardiomyopathy (DCM) is a cardiac condition resulting from myocardial damage caused by diabetes mellitus (DM), currently lacking specific therapeutic interventions. Fuzhengkangfu decoction (FZK) plays an important role in the prevention and treatment of various cardiovascular diseases. However, the efficacy and potential mechanisms of FZK are not fully understood. This study aims to investigate the protective effect and mechanisms of FZK against DCM.

METHODOLOGIES

Rats were given a high-calorie diet along with a low dosage of streptozotocin (STZ) to establish a rat model of DCM. The diabetic rats received FZK or normal saline subcutaneously for 12 weeks. Echocardiography was conducted to evaluate their heart function characteristics. Rat heart morphologies were assessed using Sirius Red staining and H&E staining. Transcriptome sequencing analysis and network pharmacology were used to reveal possible targets and mechanisms. Molecular docking was conducted to validate the association between the primary components of FZK and the essential target molecules. Finally, both in vitro and in vivo studies were conducted on the cardioprotective properties and mechanism of FZK.

RESULTS

According to the results of network pharmacology, FZK may prevent DCM by reducing oxidative stress and preventing apoptosis. Transcriptomics confirmed that FZK protected against DCM-induced myocardial fibrosis and remodelling, as predicted by network pharmacology, and suggested that FZK regulated the expression of oxidative stress and apoptosis-related proteins. Integrating network pharmacology and transcriptome analysis results revealed that the AGE-RAGE signalling pathway-associated MMP2, SLC2A1, NOX4, CCND1, and CYP1A1 might be key targets. Molecular docking showed that Poricoic acid A and 5-O-Methylvisammioside had the highest docking activities with these targets. We further conducted in vivo experiments, and the results showed that FZK significantly attenuated left ventricular remodelling, reduced myocardial fibrosis, and improved cardiac contractile function. And, our study demonstrated that FZK effectively reduced oxidative stress and apoptosis of cardiomyocytes. The data showed that Erk, NF-κB, and Caspase 3 phosphorylation was significantly inhibited, and Bcl-2/Bax was significantly increased after FZK treatment. In vitro, FZK significantly reduced AGEs-induced ROS increase and apoptosis in cardiomyocytes. Furthermore, FZK significantly inhibited the phosphorylation of Erk and NF-κB proteins and decreased the expression of MMP2. All the results confirmed that FZK inhibited the activation of the Erk/NF-κB pathway in AGE-RAGE signalling and alleviated oxidative stress and apoptosis of cardiomyocytes. In summary, we verified that FZK protects against DCM by inhibiting myocardial apoptotic remodelling through the suppression of the AGE-RAGE signalling pathway.

CONCLUSION

In conclusion, our research indicates that FZK demonstrates anti-cardiac dysfunction properties by reducing oxidative stress and cardiomyocyte apoptosis through the AGE-RAGE pathway in DCM, showing potential for therapeutic use.

METTL14-mediated N6-methyladenosine modification induces the ferroptosis of hypoxia/reoxygenation-induced cardiomyocytes

BACKGROUND

Hypoxia/reoxygenation (H/R) induces cardiomyocyte ferroptosis, a core remodeling event in myocardial ischemia/reperfusion injury. Methyltransferase-like 14 (METTL14) emerges as a writer of N6-methyladenosine (m6A) modification. This study was conducted to decipher the role of METTL14 in H/R-induced cardiomyocyte ferroptosis.

METHODS

Mouse cardiomyocytes HL-1 were cultured and underwent H/R treatment. The degree of ferroptosis after H/R treatment was appraised by the cell counting kit-8 assay, assay kits (ROS/GSH/Fe2+), and Western blotting (GPX4/ACSL4). The intracellular expressions of METTL14, pri-miR-146a-5p, miR-146a-5p, or adaptor protein phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1) were examined by real-time quantitative polymerase chain reaction or Western blotting, with m6A quantification analysis and RNA immunoprecipitation to determine the total m6A level and the expression of pri-miR-146a-5p bound to DiGeorge critical region 8 (DGCR8) and m6A-modified pri-miR-146a-5p. The binding of miR-146a-5p to APPL1 was testified by the dual-luciferase assay.

RESULTS

H/R treatment induced cardiomyocyte ferroptosis (increased ROS, Fe2+, and ACSL4 and decreased GSH and GPX4) and upregulated METTL14 expression. METTL14 knockdown attenuated H/R-induced cardiomyocyte ferroptosis. METTL14 induced the recognition of pri-miR-146a-5p by DGCR8 by increasing m6A modification on pri-miR-146a-5p, which promoted the conversion of pri-miR-146a-5p into miR-146a-5p and further repressed APPL1 transcription. miR-146a-5p upregulation or APPL1 downregulation limited the inhibitory effect of METTL14 downregulation on H/R-induced cardiomyocyte ferroptosis.

CONCLUSION

METTL14 promoted miR-146a-5p expression through the recognition and processing of pri-miR-146a-5p by DGCR8, which repressed APPL1 transcription and triggered H/R-induced cardiomyocyte ferroptosis.

M2 macrophage‑derived exosomes alleviate KCa3.1 channel expression in rapidly paced HL‑1 myocytes via the NF‑κB (p65)/STAT3 signaling pathway

The present study was designed to explore the role of M2 macrophage‑derived exosomes (M2‑exos) on the KCa3.1 channel in a cellular atrial fibrillation (AF) model using rapidly paced HL‑1 myocytes. M2 macrophages and M2‑exos were isolated and identified. MicroRNA (miR)‑146a‑5p levels in M2 macrophages and M2‑exos were quantified using reverse transcription‑quantitative PCR (RT‑qPCR). HL‑1 myocytes were randomly divided into six groups: Control group, pacing group, pacing + coculture group (pacing HL‑1 cells cocultured with M2‑exos), pacing + mimic‑miR‑146a‑5p group, pacing + NC‑miR‑146a‑5p group and pacing + pyrrolidine dithiocarbamate (PDTC; a special blocker of the NF‑κB signaling pathway) group. Transmission electron microscopy, nanoparticle tracking analysis, western blotting, RT‑qPCR and immunohistochemistry were performed in the present study. A whole‑cell clamp was also applied to record the current density of KCa3.1 and action potential duration (APD) in each group. The results revealed that miR‑146a‑5p was highly expressed in both M2 macrophages and M2‑exos. Pacing HL‑1 cells led to a shorter APD, an increased KCa3.1 current density and higher protein levels of KCa3.1, phosphorylated (p‑)NF‑κB p65, p‑STAT3 and IL‑1β compared with the control group. M2‑exos, miR‑146a‑5p‑mimic and PDTC both reduced the protein expression of KCa3.1, p‑NF‑κB p65, p‑STAT3 and IL‑1β and the current density of KCa3.1, resulting in a longer APD in the pacing HL‑1 cells. In conclusion, M2‑exos and their cargo, which comprised miR‑146a‑5p, decreased KCa3.1 expression and IL‑1β secretion in pacing HL‑1 cells via the NF‑κB/STAT3 signaling pathway, limiting the shorter APD caused by rapid pacing.

Cardioprotective effect of naringin against the ischemia/reperfusion injury of aged rats

Aging is known as a main risk factor in the development of cardiovascular diseases. Naringin (NRG) is a flavonoid compound derived from citrus fruits. It possesses a wide spectrum of pharmacological properties, including antioxidant anti-inflammatory, and cardioprotective. This investigation aimed to assess the cardioprotective effect of NRG against the ischemia/reperfusion (I/R) injury in aged rats. In this study, D-galactose (D-GAL) at the dose of 150 mg/kg/day for 8 weeks was used to induce aging in rats. Rats were orally gavaged with NRG (40 or 100 mg/kg/day), in co-treatment with D-GAL, for 8 weeks. The Langendorff isolated heart was used to evaluate the effect of NRG on I/R injury in aged rats. NRG treatment diminished myocardial hypertrophy and maximum contracture level in aged animals. During the pre-ischemic phase, reduced heart rate was normalized by NRG. The effects of D-GAL on the left ventricular end diastolic pressure (LVDP), the rate pressure product (RPP), and the minimum and maximum rate of left ventricular pressure (±dp/dt) improved by NRG treatment in the perfusion period. NRG also enhanced post-ischemic recovery of cardiac functional parameters (± dp/dt, and RPP) in isolated hearts. An increase in serum levels of the lactate dehydrogenase (LDH), the creatine kinase-MB (CK-MB), and the tumor necrosis factor-alpha (TNF-α) were reversed by NRG in aged rats. It also normalized the D-GAL-decreased the superoxide dismutase (SOD) activity in the heart tissue. NRG treatment alleviated cardiac injury in aged hearts under conditions of I/R. NRG may improve aging-induced cardiac dysfunction through anti-oxidative and anti-inflammatory mechanisms.

Identification of key biomarkers associated with immune cells infiltration for myocardial injury in dermatomyositis by integrated bioinformatics analysis

BACKGROUND

Dermatomyositis (DM) is an acquired autoimmune disease that can cause damage to various organs, including the heart muscle. However, the mechanisms underlying myocardial injury in DM are not yet fully understood.

METHODS

In this study, we utilized publicly available datasets from the Gene Expression Omnibus (GEO) database to identify hub-genes that are enriched in the immune system process in DM and myocarditis. Weighted gene co-expression network analysis (WGCNA), differentially expressed genes (DEGs) analysis, protein-protein interaction (PPI), and gene ontology (GO) analysis were employed to identify these hub-genes. We then used the CIBERSORT method to analyze immune cell infiltration in skeletal muscle specimens of DM and myocardium specimens of myocarditis respectively. Correlation analysis was performed to investigate the relationship between key genes and infiltrating immune cells. Finally, we predicted regulatory miRNAs of hub-genes through miRNet and validated their expression in online datasets and clinical samples.

RESULTS

Using integrated bioinformatics analysis, we identified 10 and 5 hub-genes that were enriched in the immune system process in the database of DM and myocarditis respectively. The subsequent intersections between hub-genes were IFIT3, OAS3, ISG15, and RSAD2. We found M2 macrophages increased in DM and myocarditis compared to the healthy control, associating with the expression of IFIT3, OAS3, ISG15, and RSAD2 in DM and myocarditis positively. Gene function enrichment analysis (GSEA) showed that IFIT3, OAS3, ISG15, and RSAD2 were mainly enriched in type I interferon (IFN) signaling pathway, cellular response to type I interferon, and response to type I interferon. Finally, we verified that the expression of miR-146a-5p was significantly higher in the DM with myocardial injury than those without myocardial injury (p = 0.0009).

CONCLUSION

Our findings suggest that IFIT3, OAS3, ISG15, and RSAD2 may play crucial roles in the underlying mechanism of myocardial injury in DM. Serum miR-146a-5p could be a potential biomarker for myocardial injury in DM.