MicroRNA-130 as a critical modulator of cardiac remodeling: interplay between autophagic flux and ferroptotic pathways in acute myocardial infarction.

Acute myocardial infarction (AMI) is one of the major causes of morbidity and mortality in the world. Ischemia/reperfusion (I/R) injury-induced cardiomyocytes death is the main obstacle that limits the heart function recovery of the AMI patients. Reactive oxygen species (ROS) generated by mitochondria is the main pathological stimulus of cardiomyocytes death during heart I/R injury process. Hence, to understand the underlying mechanism of cardioymocytes proliferation and apoptosis under oxidative stress is crucial for effective AMI therapy. In this study, we found that the expression of long non-coding RNA HOTAIR was significantly downregulated in H9c2 cells in response to oxidative stimuli. HOTAIR knockdown further attenuated H9c2 cells proliferation and accelerated H9c2 cells apoptosis in oxidative stress, while HOTAIR overexpression can protect H9c2 cells from oxidative stress-induced injury. Additionally, HOTAIR acted as a sponge for miR-125. MiR-125 inhibitors restored the H9c2 cells proliferation and migration potential after HOTAIR knockdown in oxidative stress. Meanwhile, MMP2 was identified as a target of miR-125. MMP2 knockdown blocked miR-125 inhibitors' protect effect on H9c2 cells in oxidative stress. Further study demonstrated that HOTAIR inhibition can aggravate oxidative stress-induced H9c2 cells injury through HOTAIR/miR-125/MMP2 axis. Our finding revealed a novel regulatory mechanism for cardiomyocytes proliferation and apoptosis under oxidative stress conditions, which provided a therapeutic approach for myocardium repair after AMI injury.

It was reported that serum apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1) level was higher in acute myocardial infarction (AMI) patients than in angina. This study aimed to investigate the role and mechanism of APEX1 in AMI progression. The mRNA and protein levels of APEX1 and zinc finger CCHC domain containing 9 (ZCCHC9) in blood specimens of AMI patients and normal controls were determined by RT-qPCR and Western blot assays, respectively. H9c2 cardiomyocytes were treated with angiotensin II (Ang II) to induce cardiomyocyte injury and then transfected with small interfering RNA against APEX1 (si-APEX1) or overexpression plasmids of ZCCHC9 (pcDNA-ZCCHC9). The cell viability, apoptosis, inflammatory cytokine levels, and fibrosis-associated protein expression in H9c2 cells were evaluated. ZCCHC9 promoter methylation were detected with methylation-specific PCR (MSP) assay. Then, rescue experiments were performed to explore whether APEX1 mediated cardiomyocyte functions by regulating ZCCHC9 expression. Furthermore, we explored whether the APEX1/ZCCHC9 axis regulated cardiomyocyte injury in AMI via the p38 MAPK signaling pathway. Additionally, an AMI rat model was established using the left anterior descending artery (LAD) ligation method and multipoint intramyocardial injection (5 points, 2 µL/point) of lentivirus (1 × 109 TU/mL) carrying scramble or si-APEX1 was conducted before modeling. The rats were euthanized four weeks after AMI modeling, and blood samples and myocardial tissues were harvested. The infarct area, cell apoptosis, inflammation, and fibrosis in myocardial tissues were detected. APEX1 was upregulated and ZCCHC9 was downregulated in blood samples of AMI patients compared with normal controls. APEX1 knockdown or ZCCHC9 overexpression attenuated Ang II-induced viability reduction, apoptosis, inflammation, and fibrosis in cardiomyocytes. APEX1 inhibited ZCCHC9 expression by promoting DNA methyltransferase 1 (DNMT1)-mediated ZCCHC9 promoter methylation. ZCCHC9 knockdown abolished the protective effects of APEX1 knockdown on Ang II-induced cardiomyocyte injury. APEX1 knockdown inhibited the p38 MAPK signal signaling, and anisomycin reversed the effect of APEX1 knockdown on cardiomyocyte functions. Additionally, APEX1 knockdown alleviated apoptosis, inflammation, and fibrosis in myocardial tissues of AMI rats. APEX1 knockdown attenuated Ang II-induced apoptosis, inflammation, and fibrosis in cardiomyocytes although promoting ZCCHC9 expression and inhibiting the p38 MAPK signaling pathway, thus relieving myocardial infarction, inflammation, and fibrosis in AMI rats.

ABSTRACTExosomes secreted by human umbilical cord mesenchymal stem cells (hucMSCs) protect cardiomyocytes from anoxia-reoxygenation injury. But the mechanism of hucMSC-exo-microRNA (miR)-19a in acute myocardial infarction (AMI) remains unclear. For this study, cardiac function related indicators, inflammatory factors and markers of myocardial injury, cardiomyocyte injury, infarct size, and apoptosis were detected in vivo experiments. The gain-and loss-of function was performed to evaluate the effects of hucMSC-exo with down/upregulated miR-19a on AMI rats and hypoxic H9C2 cells. Western blot analysis was used to detect levels of AKT/JNK3/caspase-3 axis-related proteins. Consequently, hucMSC-exo alleviated AMI and inhibited cardiomyocyte apoptosis. miR-19a was downregulated in AMI tissues and cells, and increased after hucMSC-exo treatment. miR-19a knockdown in hucMSC-exo impaired the protective role of hucMSC-exo alone in the AMI damage. SOX6 is a target gene of miR-19a and its inhibition lightened hypoxic damage of H9C2 cells. SOX6 knockdown together with miR-19a inhibition in hucMSC-exo activated AKT and inhibited JNK3/caspase-3 axis. Taken together, hucMSC-exo protected cardiomyocytes from AMI injury by transferring miR-19a, targeting SOX6, activating AKT, and inhibiting JNK3/caspase-3 activation. This study may provide new understanding for AMI treatment.

Acute myocardial infarction (AMI) often occurs suddenly and leads to fatal consequences. Ferroptosis is closely related to the progression of AMI. However, the specific mechanism of ferroptosis in AMI remains unclear. We constructed a cell model of AMI using AC16 cells under oxygen and glucose deprivation (OGD) conditions and a mice model of AMI using the left anterior descending (LAD) ligation. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide was employed to determine cell viability. The levels of lactate dehydrogenase, creatine kinase, reactive oxygen species (ROS), glutathione (GSH), malondialdehyde (MDA), and iron were measured using corresponding kits. Dual luciferase reporter gene assay, RNA-binding protein immunoprecipitation, and RNA pull-down were performed to validate the correlations among AC005332.7, miR-331-3p, and cyclin D2 (CCND2). Hematoxylin and eosin staining was employed to evaluate myocardial damage. AC005332.7 and CCND2 were lowly expressed, while miR-331-3p was highly expressed in vivo and in vitro models of AMI. AC005332.7 sufficiency reduced ROS, MDA, iron, and ACSL4 while boosting the GSH and GPX4, indicating that AC005332.7 sufficiency impeded ferroptosis to improve cardiomyocyte injury in AMI. Mechanistically, AC005332.7 interacted with miR-331-3p, and miR-331-3p targeted CCND2. Additionally, miR-331-3p overexpression or CCND2 depletion abolished the suppressive impact of AC005332.7 on ferroptosis in OGD-induced AC16 cells. Moreover, AC005332.7 overexpression suppressed ferroptosis in mice models of AMI. AC005332.7 suppressed ferroptosis in OGD-induced AC16 cells and LAD ligation-operated mice through modulating miR-331-3p/CCND2 axis, thereby mitigating the cardiomyocyte injury in AMI, which proposed novel targets for AMI treatment.

Clusterin regulates TRPM2 to protect against myocardial injury induced by acute myocardial infarction injury

MicroRNAs (miRNAs) have been reported to play critical roles in the occurrence, progression, and treatment of many cardiovascular diseases. However, the molecular mechanism by which miRNA regulates target gene expression in ischemia-reperfusion (I/R) injury in acute myocardial infarction (AMI) is not entirely clear. MiR-340-5p was reported to be downregulated in acute ischemic stroke. However, it still remains unknown whether miR-340-5p is mediated in the pathogenesis process of I/R injury after AMI. In the present study, male C57BL/6 J mice and H9C2 cardiomyocytes were used as experimental models. Real-time polymerase chain reaction analysis, Western blot analysis, and theterminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling immunofluorescence staining assay were conducted to examine related indicators in the study. We confirmed that the expression of miR-340-5p is downregulated after I/R in AMI mice and hypoxia/reperfusion (H/R)-induced cardiomyocytes. miR-340-5p could inhibit apoptosis and oxidative stress in H/R-induced H9C2 cells via downregulating activator 1 (Act1). The inhibiting action of miR-340-5p on H/R-induced apoptosis and oxidative stress in cardiomyocytes was partially reversed after Act1 overexpression. Moreover, the results showed that the NF-κB pathway may be mediated in the role of miR-340-5p on H/R-induced cardiomyocyte apoptosis and oxidative stress. We demonstrated that upregulation of miR-340-5p suppresses apoptosis and oxidative stress induced by H/R in H9C2 cells by inhibiting Act1. Therapeutic strategies that target miR-340-5p, Act1, and the NF-κB pathway could be beneficial for the treatment of I/R injury after AMI.

To determine whether interleukin-8 (IL-8, a potent activator of neutrophils) is involved in tissue injury during ischaemia and reperfusion in patients with acute myocardial infarction. Teaching hospital. Five consecutive patients with acute Q-wave myocardial infarction, two patients with stable angina who underwent elective percutaneous transluminal coronary angioplasty, and 10 normal controls. Serum IL-8 concentration measured by enzyme linked immunosorbent assay (ELISA) over time (every four, eight or 12 hours for 36-72 hours). All five patients with acute myocardial infarction had a transient but significant rise in serum IL-8 concentration (13-1100 ng/l) within 22 hours after the onset of symptoms, whereas IL-8 was not detected in any of the samples from patients with angina pectoris or normal controls. One patient who died of pump failure and two patients who had mild congestive heart failure showed the highest values (1100, 920, and 190 ng/l respectively). Serum IL-8 concentration showed a transient rise during the very early phase of acute myocardial infarction. In combination with several recent lines of evidence indicating the importance of injurious activities of neutrophils as a cause of tissue damage in acute myocardial infarction and the potent stimulation of neutrophils by IL-8, these results strongly suggest that IL-8 is important in the development of myocardial injury in acute myocardial infarction.

Plasma exosomes from patients with acute myocardial infarction alleviate myocardial injury by inhibiting ferroptosis through miR-26b-5p/SLC7A11 axis

To investigate the role of miRNA-15b in cardiomyocyte apoptosis after ischemia reperfusion injury in acute myocardial infarction (AMI), we conducted the AMI rat model by using left anterior descending ligation...

Background: Acute kidney injury (AKI) is associated with increased morbidity and mortality in patients with acute myocardial infarction (AMI). Use of trans-valvular pumps and veno-arterial extracorporeal membrane oxygenation (VA-ECMO) for patients with AMI is growing. Trans-valvular pumps transfer rotational kinetic energy to blood and generate flow from the left ventricle into the ascending aorta. VA-ECMO drains blood from the venous system and returns oxygenated blood into the descending aorta, thereby increasing systemic perfusion. The impact of these support strategies on renal blood flow and function remains poorly understood. We hypothesized that compared to a trans-valvular pump, VA-ECMO is associated with increased renal injury in AMI. Methods and Results: Adult male swine were subjected to left anterior descending artery occlusion for 90 minutes followed by either immediate reperfusion (IRI), trans-valvular pumping (Impella CP) or VA-ECMO starting 30 minutes before reperfusion, or sham-operated controls (n=4/group). Compared to IRI, urinary levels of the biomarker kidney injury molecular 1 (KIM-1) were increased by VA-ECMO, not Impella. Inflammatory factors IL6 and IL1beta were increased by VA-ECMO, not Impella in both plasma and cortex tissue by ELISA analysis. KIM-1 protein expression for precursor KIM-1 and the extracellular domain (soluble) of KIM-1, as well as STAT3, HIF1alpha were analyzed by Western blot. Compared to sham, IRI and VA-ECMO reduced levels of soluble KIM-1 and increased levels of the KIM-1 protein precursor, pSTAT3 and HIF1a in the renal cortex. Impella had no impact on these protein levels. Conclusion: This is first study to identify that VA-ECMO, not Impella, increases urinary levels of KIM-1 , a highly sensitive biomarker of acute kidney injury. The shedding of KIM-1 extracellular domain from the renal cortex is associated with systemic inflammatory response. These findings may identity novel approaches to limit renal injury in AMI patients requiring mechanical circulatory support.

The Western Washington Intracoronary Streptokinase randomized trial1 first demonstrated that intracoronary thrombolytic therapy improved survival for patients presenting within 12 hours of symptom onset of acute myocardial infarction (MI). Perhaps equally important, this invasive study demonstrated that in-hospital and long-term survival was greatly improved in patients with patent infarct-related arteries.2 These observations ushered in the modern era of reperfusion therapy, and they also firmly established the concept that achieving arterial patency was the predominant mechanism for the prognostic benefit of thrombolytic agents. Numerous trials since then have validated this open-artery hypothesis.3 4 5 In the early 1990s, Ross et al6 definitively established the relationship between prompt reinstitution of flow, improved myocardial salvage, and survival. Anderson et al7 clearly demonstrated that antegrade flow, as defined by the Thrombolysis in Myocardial Infarction (TIMI) criteria, can differentiate different levels of antegrade flow, with different prognostic implications. Although TIMI flow grades seem to segregate effective from ineffective flow, this analysis is only a qualitative measure that can be subject to bias and interlaboratory variability. Gibson et al8 further refined angiographic flow quantitation using corrected TIMI frame counts. This method of analysis quantitates angiographic contrast velocity measures and decreases variability. Currently, arterial patency is the gold standard for assessing the efficacy of different reperfusion protocols. Refinements in the quantitation of degrees of arterial patency have led to improvements in the prognostic value of this measure. It has, however, become increasingly apparent that contrast velocity alone does not adequately define the level of microvascular perfusion or predict the extent of return of myocardial function after successful reperfusion therapy. Coronary angiography remains a crude means to assess myocardial perfusion after infarction, and it is clear that infarct artery patency is not equivalent to the reestablishment of myocardial tissue perfusion. With the …

Cyclosporin is an immunosuppressant that has recently been proposed as a treatment to prevent reperfusion injury in acute myocardial infarction (MI). We aimed to determine the overall efficacy of cyclosporin in experimental studies of acute reperfused MI. We conducted a systematic review and stratified meta-analysis of published studies describing the efficacy of cyclosporin in experimental models of acute reperfused MI. We included all in vivo publications of cyclosporin where infarct size was measured. A literature search identified 29 potential studies of which 20 fulfilled the eligibility criteria. In these studies (involving four species of animals), cyclosporin reduced myocardial infarct size by a standardized mean (95% confidence interval) difference of -1.60 (-2.17, -1.03) compared with controls. Cyclosporin failed to demonstrate a convincing benefit in studies involving pigs. Despite this observation, the overall efficacy of cyclosporin did not differ across species (P= 0.358). The dose of cyclosporin given did not affect final infarct size (P= 0.203). Funnel plots of these data suggested heterogeneity among the studies. Cyclosporin had variable effects on infarct size compared with placebo. Cyclosporin had no effect on myocardial infarct size in swine, raising a question over the potential cardioprotective effects of cyclosporin in man.

Remote cyclic compression ameliorates myocardial infarction injury in rats via AMPK-dependent pathway.

Homocysteine is a highly reactive, sulfur‐containing amino acid formed as a byproduct of the metabolism of the essential amino acid methionine. Homocysteine used to be thought of as a risk factor for atherosclerosis, but emerging data have suggested that S‐adenosylhomocysteine (SAH), an intermediate metabolite of homocysteine, might be a better indicator of vascular diseases. In this study, we investigated the epigenetic role and clinical significance of SAH‐homocysteine homeostasis in acute myocardial infarction. A cell culture system was established to assess the interplay between SAH and homocysteine using human coronary artery endothelial cells (ECs). Homocysteine alone did not affect EC survival up to 500 uM; however, in the presence of adenosine/EHNA, homocysteine (25–500 uM) dose‐dependently increased intracellular SAH and promoted TUNEL‐positive apoptotic cell death. There was a concomitant downregulation of fibroblast growth factor 2 (FGF2), a critical cytokine for EC survival, through extensive DNA methylation at CpG dinucleotides in the FGF2 gene promoter. These pro‐apoptotic effects in ECs were markedly attenuated when adenosine/EHNA was removed from the culture medium. In patients with acute ST‐elevation myocardial infarction (STEMI), the plasma SAH levels quantitated by liquid chromatography coupled to tandem mass spectrometry (LC‐MS/MS) were significantly higher than those in healthy controls. In contrast, the plasma homocysteine concentrations were similar between STEMI and healthy subjects. Moreover, STEMI patients who had an obvious clinical improvement also demonstrated a significant decrease in their plasma SAH levels at subsequent follow‐up. Our data conclude that the perturbation of SAH‐homocysteine homeostasis in ECs leads to cellular epigenetic modification and endothelial injury in acute myocardial infarction. Elevation of plasma SAH but not homocysteine in STEMI patients further supports the notion that SAH is a better indicator of vascular diseases than homocysteine.Support or Funding InformationThis work was supported by grants NSC101‐2320‐B‐002‐026 from the National Science Council and MOST‐106‐2314‐B‐002 ‐156 ‐MY2 (Dr. Po‐Yuan Chang) from the Ministry of Science and Technology, Taipei, Taiwan.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Degeneration of capsaicin sensitive sensory nerves enhances myocardial injury in acute myocardial infarction in rats