NMDA receptor-driven calcium influx promotes ischemic human cardiomyocyte apoptosis through a p38 MAPK-mediated mechanism

Inhibition of cysteine-serine-rich nuclear protein 1 ameliorates ischemia-reperfusion injury during liver transplantation in an MAPK-dependent manner

Hepatic ischemia-reperfusion injury (HIRI) is a critical pathophysiological process during liver transplantation (LT). Multiple genes and signal pathways are dysregulated during HIRI. This study aims to identify genes as potential therapeutic targets for ameliorating HIRI. Datasets containing samples from the human donor liver (GSE151648) and mouse HIRI model (GSE117066) were analyzed to determine differentially expressed genes (DEGs). The selected DEGs were confirmed by real-time PCR and western blot in the hepatocyte hypoxia-reoxygenation (HR) model, mouse HIRI model, and human liver samples after transplantation. Genetic inhibition was used to further clarify the underlying mechanism of the gene in vitro and in vivo. Among the DEGs, CSRNP1 was significantly upregulated (|log FC|= 2.08, P < 0.001), and was positively correlated with the MAPK signal pathway (R = 0.67, P < 0.001). CSRNP1 inhibition by siRNA significantly suppressed apoptosis in the AML-12 cell line after HR (mean Annexin+ ratio = 60.62% vs 42.47%, P = 0.0019), but the protective effect was eliminated with an additional MAPK activator. Knocking down CSRNP1 gene expression by intravenous injection of AAV-shRNA markedly reduced liver injury in mouse HIRI model (ALT: AAV-NC vs AAV-shCsrnp1 = 26,673.5 ± 2761.2 vs 3839.7 ± 1432.8, P < 0.001; AST: AAV-NC vs AAV-shCsrnp1 = 8640.5 ± 1450.3 vs 1786.8 ± 518.3, P < 0.001). Liver-targeted delivery of siRNA by nanoparticles effectively inhibited intra-hepatic genetic expression of Csrnp1 and alleviated IRI by reducing tissue inflammation and hepatocyte apoptosis. Furthermore, CSRNP1 inhibition was associated with reduced activation of the MAPK pathway both in vitro and in vivo. In conclusion, our results demonstrated that CSRNP1 could be a potential therapeutic target to ameliorate HIRI in an MAPK-dependent manner.

Integrative analyses and validation of ferroptosis-related genes and mechanisms associated with cerebrovascular and cardiovascular ischemic diseases

BACKGROUND

There has been a gradual increase in the occurrence of cardiovascular and cerebrovascular ischemic diseases, particularly as comorbidities. Yet, the mechanisms underlying these diseases remain unclear. Ferroptosis has emerged as a potential contributor to cardio-cerebral ischemic processes. Therefore, this study investigated the shared biological mechanisms between the two processes, as well as the role of ferroptosis genes in cardio-cerebral ischemic damage, by constructing co-expression modules for myocardial ischemia (MI) and ischemic stroke (IS) and a network of protein-protein interactions, mRNA-miRNA, mRNA-transcription factors (TFs), mRNA-RNA-binding proteins (RBPs), and mRNA-drug interactions.

RESULTS

The study identified seven key genes, specifically ACSL1, TLR4, ADIPOR1, G0S2, PDK4, HP, PTGS2, and subjected them to functional enrichment analysis during ischemia. The predicted miRNAs were found to interact with 35 hub genes, and interactions were observed between 11 hub genes and 30 TF transcription factors. Additionally, 10 RBPs corresponding to 16 hub genes and 163 molecular compounds corresponding to 30 hub genes were identified. This study also clarified the levels of immune infiltration between MI and IS and different subtypes. Finally, we identified four hub genes, including TLR4, by using a diagnostic model constructed by Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis; ADIPOR1, G0S2, and HP were shown to have diagnostic value for the co-pathogenesis of MI and cerebral ischemia by both validation test data and RT-qPCR assay.

CONCLUSIONS

To the best our knowledge, this study is the first to utilize multiple algorithms to comprehensively analyze the biological processes of MI and IS from various perspectives. The four hub genes, TLR4, ADIPOR1, G0S2, and HP, have proven valuable in offering insights for the investigation of shared injury pathways in cardio-cerebral injuries. Therefore, these genes may serve as diagnostic markers for cardio-cerebral ischemic diseases.

The purified extract of steamed Panax ginseng protects cardiomyocyte from ischemic injury via caveolin-1 phosphorylation-mediating calcium influx

Background

Caveolin-1, the scaffolding protein of cholesterol-rich invaginations, plays an important role in store-operated Ca2+ influx and its phosphorylation at Tyr14 (p-caveolin-1) is vital to mobilize protection against myocardial ischemia (MI) injury. SOCE, comprising STIM1, ORAI1 and TRPC1, contributes to intracellular Ca2+ ([Ca2+]i) accumulation in cardiomyocytes. The purified extract of steamed Panax ginseng (EPG) attenuated [Ca2+]i overload against MI injury. Thus, the aim of this study was to investigate the possibility of EPG affecting p-caveolin-1 to further mediate SOCE/[Ca2+]i against MI injury in neonatal rat cardiomyocytes and a rat model.

Methods

PP2, an inhibitor of p-caveolin-1, was used. Cell viability, [Ca2+]i concentration were analyzed in cardiomyocytes. In rats, myocardial infarct size, pathological damages, apoptosis and cardiac fibrosis were evaluated, p-caveolin-1 and STIM1 were detected by immunofluorescence, and the levels of caveolin-1, STIM1, ORAI1 and TRPC1 were determined by RT-PCR and Western blot. And, release of LDH, cTnI and BNP was measured.

Results

EPG, ginsenosides accounting for 57.96%, suppressed release of LDH, cTnI and BNP, and protected cardiomyocytes by inhibiting Ca2+ influx. And, EPG significantly relieved myocardial infarct size, cardiac apoptosis, fibrosis, and ultrastructure abnormality. Moreover, EPG negatively regulated SOCE via increasing p-caveolin-1 protein, decreasing ORAI1 mRNA and protein levels of ORAI1, TRPC1 and STIM1. More importantly, inhibition of the p-caveolin-1 significantly suppressed all of the above cardioprotection of EPG.

Conclusions

Caveolin-1 phosphorylation is involved in the protective effects of EPG against MI injury via increasing p-caveolin-1 to negatively regulate SOCE/[Ca2+]i.

Research progress and perspectives of N-methyl-D-aspartate receptor in myocardial and cerebral ischemia-reperfusion injury: A review

There is an urgent need to find common targets for precision therapy, as there are no effective preventive therapeutic measures for combined clinical heart-brain organ protection and common pathways associated with glutamate receptors are involved in heart-brain injury, but current glutamate receptor-related clinical trials have failed. Ischemia-reperfusion injury (IRI) is a common pathological condition that occurs in multiple organs, including the heart and brain, and can lead to severe morbidity and mortality. N-methyl-D-aspartate receptor (NMDAR), a type of ionotropic glutamate receptor, plays a crucial role in the pathogenesis of IRI. NMDAR activity is mainly regulated by endogenous activators, agonists, antagonists, and voltage-gated channels, and activation leads to excessive calcium influx, oxidative stress, mitochondrial dysfunction, inflammation, apoptosis, and necrosis in ischemic cells. In this review, we summarize current research advances regarding the role of NMDAR in myocardial and cerebral IRI and discuss potential therapeutic strategies to modulate NMDAR signaling to prevent and treat IRI.

Bioinformatics and experimental analyses of glutamate receptor and its targets genes in myocardial and cerebral ischemia

BACKGROUND

There is a mutual hemodynamic and pathophysiological basis between the heart and brain. Glutamate (GLU) signaling plays an important role in the process of myocardial ischemia (MI) and ischemic stroke (IS). To further explore the common protective mechanism after cardiac and cerebral ischemic injuries, the relationship between GLU receptor-related genes and MI and IS were analyzed.

RESULTS

A total of 25 crosstalk genes were identified, which were mainly enriched in the Toll-like receptor signaling pathway, Th17 cell differentiation, and other signaling pathways. Protein-protein interaction analysis suggested that the top six genes with the most interactions with shared genes were IL6, TLR4, IL1B, SRC, TLR2, and CCL2. Immune infiltration analysis suggested that immune cells such as myeloid-derived suppressor cells and monocytes were highly expressed in the MI and IS data. Memory B cells and Th17 cells were expressed at low levels in the MI and IS data; molecular interaction network construction suggested that genes such as JUN, FOS, and PPARA were shared genes and transcription factors; FCGR2A was a shared gene of MI and IS as well as an immune gene. Least absolute shrinkage and selection operator logistic regression analysis identified nine hub genes: IL1B, FOS, JUN, FCGR2A, IL6, AKT1, DRD4, GLUD2, and SRC. Receiver operating characteristic analysis revealed that the area under the curve of these hub genes was > 65% in MI and IS for all seven genes except IL6 and DRD4. Furthermore, clinical blood samples and cellular models showed that the expression of relevant hub genes was consistent with the bioinformatics analysis.

CONCLUSIONS

In this study, we found that the GLU receptor-related genes IL1B, FOS, JUN, FCGR2A, and SRC were expressed in MI and IS with the same trend, which can be used to predict the occurrence of cardiac and cerebral ischemic diseases and provide reliable biomarkers to further explore the co-protective mechanism after cardiac and cerebral ischemic injury.

The Emerging Role of N-Methyl-D-Aspartate (NMDA) Receptors in the Cardiovascular System: Physiological Implications, Pathological Consequences, and Therapeutic Perspectives

N-methyl-D-aspartate receptors (NMDARs) are ligand-gated ion channels that are activated by the neurotransmitter glutamate, mediate the slow component of excitatory neurotransmission in the central nervous system (CNS), and induce long-term changes in synaptic plasticity. NMDARs are non-selective cation channels that allow the influx of extracellular Na⁺ and Ca²⁺ and control cellular activity via both membrane depolarization and an increase in intracellular Ca²⁺ concentration. The distribution, structure, and role of neuronal NMDARs have been extensively investigated and it is now known that they also regulate crucial functions in the non-neuronal cellular component of the CNS, i.e., astrocytes and cerebrovascular endothelial cells. In addition, NMDARs are expressed in multiple peripheral organs, including heart and systemic and pulmonary circulations. Herein, we survey the most recent information available regarding the distribution and function of NMDARs within the cardiovascular system. We describe the involvement of NMDARs in the modulation of heart rate and cardiac rhythm, in the regulation of arterial blood pressure, in the regulation of cerebral blood flow, and in the blood-brain barrier (BBB) permeability. In parallel, we describe how enhanced NMDAR activity could promote ventricular arrhythmias, heart failure, pulmonary artery hypertension (PAH), and BBB dysfunction. Targeting NMDARs could represent an unexpected pharmacological strategy to reduce the growing burden of several life-threatening cardiovascular disorders.

Glutamatergic neurons in lateral hypothalamus play a vital role in acupuncture preconditioning to alleviate MIRI

Myocardial ischemia-reperfusion injury (MIRI) has high morbidity and mortality worldwide. Increasing evidence has shown that electroacupuncture (EA) plays a critical role in alleviating MIRI. The aim of this study is to investigate whether glutamatergic neurons in the lateral hypothalamus (LH) have vital effect on MIRI as well as the underlying mechanism during the EA pretreatment. The MIRI model was established by ligating the left anterior descending (LAD) coronary artery for 30 min followed by reperfusion for 2 h. Chemogenetics, electrocardiogram (ECG) recording, ELISA, multichannel physiology recording, and immunofluorescence staining methods were combined to demonstrate that firing frequencies of neurons in the LH and expression of c-Fos decreased by EA pretreatment. Meanwhile, EA preconditioning significantly reduced the percentage of infarct size and the levels of cardiac troponin I (cTnI) and creatine kinase isoenzymes (CK-MB) were similar to inhibition of glutamatergic neurons in LH, also attenuated morphology of myocardial tissue was induced by MIRI. However, activation of glutamatergic neurons in LH weakened the above effects of EA pretreatment.NEW & NOTEWORTHY This study demonstrates that EA preconditioning can attenuate myocardial injury for MIRI, which is similar to inhibition of glutamatergic neurons in LH. However, chemical activation of glutamatergic neurons in LH attenuates the protective effect of EA pretreatment. These findings help better understand the mechanisms of EA to regulate cardiac function.

Cardioprotective Mechanism of Leonurine against Myocardial Ischemia through a Liver–Cardiac Crosstalk Metabolomics Study

Leonurine has been shown to have excellent anti-myocardial ischemia effects. Our previous studies suggested that cardiac protection by leonurine during myocardial ischemia appeared to be inextricably linked to its regulation of the liver. At present, however, there are few mechanistic studies of leonurine and its regulation of hepatic metabolism against ischemic injury. In this study, a metabolomics approach was developed to give a global view of the metabolic profiles of the heart and liver during myocardial ischemia. Principal component analysis and orthogonal partial least squares discrimination analysis were applied to filter differential metabolites, and a debiased sparse partial correlation analysis was used to analyze the correlation of the differential metabolites between heart and liver. As a result, a total of thirty-one differential metabolites were identified, six in the myocardial tissue and twenty-five in the hepatic tissue, involving multiple metabolic pathways including glycine, serine and threonine, purine, fatty acid, and amino acid metabolic pathways. Correlation analysis revealed a net of these differential metabolites, suggesting an interaction between hepatic and myocardial metabolism. These results suggest that leonurine may reduce myocardial injury during myocardial ischemia by regulating the metabolism of glycine, serine and threonine, purine, fatty acids, and amino acids in the liver and heart.

Exosomal circRNA as a novel potential therapeutic target for multiple myeloma-related myocardial damage

Introduction

Myocardial damage is a mostly incurable complication of multiple myeloma (MM) that seriously affects the treatment outcome and quality of life of patients. Exosomal circular RNAs (exo-circRNAs) play an important role in tumor occurrence and development and are considered key factors in MM pathogenesis. However, the role and mechanism of action of exo-circRNAs in MM-related myocardial damage are still unclear. This study aimed to investigate correlations between exo-circRNAs and MM and to preliminarily explore the role of exo-circRNAs in MM-related myocardial damage.

Methods

Six MM patients and five healthy controls (HCs) were included in the study. High-throughput sequencing and qRT-PCR verification were used to obtain a profile of abnormally expressed exo-circRNAs. GO, KEGG, miRanda, TargetScan and Metascape were used for bioinformatics analyses. H9C2 cells treated with exosomes from U266 cells were used in cell experiments. CCK-8, PCR, immunofluorescence and western blotting assays were used to detect cell proliferation and expression of autophagy-related indicators. Electron microscopy was used to observe the number of autophagic vesicles.

Results

Bioinformatics analysis showed that circRNAs with upregulated expression had the potential to promote MM-related myocardial damage. In addition, PCR results confirmed that circ-G042080 was abundantly expressed in the serum exosomes of 20 MM patients. Correlation analysis showed that the expression level of circ-G042080 was positively correlated with the clinical level of MM and MM-related myocardial damage and that circ-G042080 might interfere with MM-related myocardial damage through a downstream miRNA/TLR4 axis. Cell experiments demonstrated that the circ-G042080/hsa-miR-4268/TLR4 axis might exist in H9C2 cells incubated with exosomes and cause abnormal autophagy.

Conclusion

Abnormal expression of serum exo-circRNAs was found to be associated with MM-related myocardial damage, suggesting that exo-circRNAs might become a new diagnostic marker of MM-related myocardial damage and a therapeutic target.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02011-w.

The Role of Cardiac N-Methyl-D-Aspartate Receptors in Heart Conditioning-Effects on Heart Function and Oxidative Stress

As well as the most known role of N-methyl-D-aspartate receptors (NMDARs) in the nervous system, there is a plethora of evidence that NMDARs are also present in the cardiovascular system where they participate in various physiological processes, as well as pathological conditions. The aim of this study was to assess the effects of preconditioning and postconditioning of isolated rat heart with NMDAR agonists and antagonists on heart function and release of oxidative stress biomarkers. The hearts of male Wistar albino rats were subjected to global ischemia for 20 min, followed by 30 min of reperfusion, using the Langendorff technique, and cardiodynamic parameters were determined during the subsequent preconditioning with the NMDAR agonists glutamate (100 µmol/L) and (RS)-(Tetrazol-5-yl)glycine (5 μmol/L) and the NMDAR antagonists memantine (100 μmol/L) and MK-801 (30 μmol/L). In the postconditioning group, the hearts were perfused with the same dose of drugs during the first 3 min of reperfusion. The oxidative stress biomarkers were determined spectrophotometrically in samples of coronary venous effluent. The NMDAR antagonists, especially MK-801, applied in postconditioning had a marked antioxidative effect with a most pronounced protective effect. The results from this study suggest that NMDARs could be a potential therapeutic target in the prevention and treatment of ischemic and reperfusion injury of the heart.

MiR-219a-2 relieves myocardial ischemia-reperfusion injury by reducing calcium overload and cell apoptosis through HIF1α/ NMDAR pathway

OBJECTIVE

During the process of myocardial ischemia-reperfusion injury (MIRI), the intracellular Ca²⁺ concentration ([Ca²⁺]_i) continues to increase, leads to the cardiomyocyte apoptosis and eventually causes myocardial damage, while the upstream regulation mechanism of calcium overload is still unknown. This study focuses on the role of miR-219a-2 in MIRI and aims to elaborate its regulatory mechanism on calcium overload that occurs during MIRI.

METHODS

The expression of miR-219a-2 was determined in the heart tissues of MIRI mice by qRT-PCR. The [Ca²⁺]_i was measured by fluo-3 using a fluorescence microplate reader. The expression of hypoxiainducible factor 1α (HIF1α) and NR1, the obligatory subunit of N-methyl-d-aspartate receptor 1 (NMDAR), were measured by qRT-PCR and western blot. The luciferase reporter assay was used to confirm the interplay between miR-219a-2 and HIF1α and the interplay between HIF1α and NR1. The cell apoptosis was measured by the expression level of B-cell lymphoma 2 interacting mediator of cell death (Bim) and the number of TUNEL-positive cells. The myocardial infarct size of mice was measured by TTC/Evans Blue staining.

RESULTS

MiR-219a-2 was down-regulated in the heart tissues of MIRI mice. miR-219a-2 overexpression decreased [Ca²⁺]_i and the expression of HIF1α and NR1 in hypoxia/reoxygenation (H/R)-treated HL-1 cells. Then, the luciferase reporter assay showed that miR-219a-2 inhibited the transcription of HIF1α and HIF1α promoted the transcription of NR1. Both HIF1α overexpression and NMDAR function enhancement removed the inhibitory effect of miR-219a-2 on calcium overload and cell apoptosis in H/R-treated HL-1 cells. Finally, the overexpression of miR-219a-2 decreased Ca²⁺ concentration, cell apoptosis, and myocardial infarction size in MIRI mice, while the NMDAR function enhancer reversed the therapeutic effect of miR-219a-2.

CONCLUSION

MiR-219a-2 reducing NMDAR-mediated calcium overload via HIF1α/NR1 axis, thus alleviating cell apoptosis in MIRI.

Cardioprotective effects of memantine in myocardial ischemia: Ex vivo and in vivo studies

Myocardial infarction (MI) refers to the loss of cardiomyocytes due to inadequate coronary blood flow and subsequently a reduced oxygen supply. Activation of N-methyl-D-aspartate (NMDA) receptors has been linked to myocardial infarction. The aim of the present study was to determine the cardioprotective effects of memantine, in myocardial infarction both in ex vivo and in vivo models. Effects of memantine on the electrocardiogram (ECG) pattern, cardiodynamic parameters, infarct size and lipid peroxidation were evaluated in the isolated perfused rat heart. Moreover, in in vivo studies in rats, the protective effects of memantine on isoproterenol-induced myocardial infarction model (administration of 100 mg/kg isoproterenol subcutaneously for 2 consecutive days) was evaluated by measuring ECG pattern, mean arterial pressure, malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity, cardiac tumor necrosis factor-alpha (TNF-α) level and cardiac remodeling. The results from the ex vivo isolated perfused heart showed that memantine treatment increased heart rate, left ventricular systolic pressure and left ventricular maximal rate of pressure increase, and decreased cardiac arrhythmia, MDA level and infarct size in comparison to ischemia/reperfusion (IR) group. The isoproterenol-induced MI (Iso) as used in the in vivo model demonstrated that MDA levels and MPO activity were decreased in memantine groups. Memantine treatment reduced the expression of cardiac TNF-α in comparison to Iso group. Cardiac fibrosis and hypertrophy were lower in memantine groups. In conclusion, memantine exerts cardioprotective effects in models of myocardial infarction, which may be attributed to reduction of pro-inflammatory and oxidative stress factors and subsequently a decrease in cardiac remodeling.