Role of MiR-30a in cardiomyocyte autophagy induced by Angiotensin II

Sex Influence on Autophagy Markers and miRNAs in Basal and Angiotensin II-Treated Human Umbilical Vein Endothelial Cells

Cardiovascular diseases (CVD) display many sex and gender differences, and endothelial dysfunction, angiotensin II (Ang II), and autophagy represent key factors in the autophagic process Therefore, we studied whether Ang II modulates the mentioned processes in a sex-specific way in HUVECs obtained from healthy male and female newborns. In basal HUVECs, the Parkin gene and protein were higher in FHUVECs than in MHUVECs, while the Beclin-1 protein was more expressed in MHUVECs, and no other significant differences were detected. Ang II significantly increases LAMP-1 and p62 protein expression and decreases the expression of Parkin protein in comparison to basal in MHUVECs. In FHUVECs, Ang II significantly increases the expression of Beclin-1 gene and protein, and Parkin gene. The LC3 II/I ratio and LAMP-1 protein were significantly higher in MHUVECs than in FHUVECs, while Parkin protein was significantly more expressed in Ang II-treated FHUVECs than in male cells. Ang II affects the single miRNA levels: miR-126-3p and miR-133a-3p are downregulated and upregulated in MHUVECs and FHUVECs, respectively. MiR-223 is downregulated in MHUVEC and FHUVECs. Finally, miR-29b-3p and miR-133b are not affected by Ang II. Ang II effects and the relationship between miRNAs and organelles-specific autophagy is sex-dependent in HUVECs. This could lead to a better understanding of the mechanisms underlying sex differences in endothelial dysfunction, providing useful indications for innovative biomarkers and personalized therapeutic approaches.

Cardiac injury after acute carbon monoxide poisoning and its clinical treatment scheme

This study was designed to investigate cardiac injury after acute carbon monoxide poisoning and its clinical treatment scheme. Seventy patients with moderate and severe acute carbon monoxide poisoning (ACOP) admitted from January 2017 to December 2018 into The Affiliated Hospital of Qingdao University were regarded as a research group (RG), and another 30 healthy adults undergoing physical examination in the hospital during the same period were selected as a control group (CG). Thirty-five patients in the RG who received hyperbaric oxygen therapy were considered as group A, and 35 patients who received extracorporeal membrane oxygenation therapy were considered as group B. The effective rates and complications of the two groups after treatment were compared. The concentrations of creatine kinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH) of myocardial enzymes at different time points before and after treatment were detected. Expression of miR-30a in the blood of experimental subjects was detected by time-fluorescence quantitative PCR, and the relationship between miR-30a expression and ACOP patients was analyzed. Patients in groups A and B achieved obvious efficacy, but the effective rate and incidence rate of complications in the extracorporeal membrane oxygenation (ECMO) group were better than those in the hyperbaric oxygen group. The concentrations of CK-MB and LDH in group A and group B were significantly higher than those in control group (P<0.01). The expression level of miR-30a in the RG was significantly higher than that in the control group (P<0.05). Both hyperbaric oxygen therapy and ECMO therapy have obvious efficacy on ACOP patients, but the latter is better than the former. The expression level of miR-30a in blood of ACOP patients increased significantly, which is positively correlated with myocardial injury, and it decreased after treatment. It is believed that miR-30a can provide a reference index for early diagnosis and prediction of disease progression and prognosis in cardiac injury of ACOP.

Combining Circulating MicroRNA and NT-proBNP to Detect and Categorize Heart Failure Subtypes

BACKGROUND

Clinicians need improved tools to better identify nonacute heart failure with preserved ejection fraction (HFpEF).

OBJECTIVES

The purpose of this study was to derive and validate circulating microRNA signatures for nonacute heart failure (HF).

METHODS

Discovery and validation cohorts (N = 1,710), comprised 903 HF and 807 non-HF patients from Singapore and New Zealand (NZ). MicroRNA biomarker panel discovery in a Singapore cohort (n = 546) was independently validated in a second Singapore cohort (Validation 1; n = 448) and a NZ cohort (Validation 2; n = 716).

RESULTS

In discovery, an 8-microRNA panel identified HF with an area under the curve (AUC) 0.96, specificity 0.88, and accuracy 0.89. Corresponding metrics were 0.88, 0.66, and 0.77 in Validation 1, and 0.87, 0.58, and 0.74 in Validation 2. Combining microRNA panels with N-terminal pro-B-type natriuretic peptide (NT-proBNP) clearly improved specificity and accuracy from AUC 0.96, specificity 0.91, and accuracy 0.90 for NT-proBNP alone to corresponding metrics of 0.99, 0.99, and 0.93 in the discovery and 0.97, 0.96, and 0.93 in Validation 1. The 8-microRNA discovery panel distinguished HFpEF from HF with reduced ejection fraction with AUC 0.81, specificity 0.66, and accuracy 0.72. Corresponding metrics were 0.65, 0.41, and 0.56 in Validation 1 and 0.65, 0.41, and 0.62 in Validation 2. For phenotype categorization, combined markers achieved AUC 0.87, specificity 0.75, and accuracy 0.77 in the discovery with corresponding metrics of 0.74, 0.59, and 0.67 in Validation 1 and 0.72, 0.52, and 0.68 in Validation 2, as compared with NT-proBNP alone of AUC 0.71, specificity 0.46, and accuracy 0.62 in the discovery; with corresponding metrics of 0.72, 0.44, and 0.57 in Validation 1 and 0.69, 0.48, and 0.66 in Validation 2. Accordingly, false negative (FN) (81% Singapore and all NZ FN cases were HFpEF) as classified by a guideline-endorsed NT-proBNP ruleout threshold, were correctly reclassified by the 8-microRNA panel in the majority (72% and 88% of FN in Singapore and NZ, respectively) of cases.

CONCLUSIONS

Multi-microRNA panels in combination with NT-proBNP are highly discriminatory and improved specificity and accuracy in identifying nonacute HF. These findings suggest potential utility in the identification of nonacute HF, where clinical assessment, imaging, and NT-proBNP may not be definitive, especially in HFpEF.

MiR-129-5p inhibits autophagy and apoptosis of H9c2 cells induced by hydrogen peroxide via the PI3K/AKT/mTOR signaling pathway by targeting ATG14

Ischemic heart disease (IHD) is a significant cause of cardiovascular diseases. MicroRNAs (miRNAs) have been thought to be critical regulators in the heart diseases. The present study was aimed to investigate the effect of miR-129-5p on the autophagy and apoptosis by targeting ATG14 as well as how miR-129-5p worked through the PI3K/AKT/mTOR signaling pathway in H₂O₂-induced H9c2 cells. H9c2 cells were induced by H₂O₂, after which the expression of miR-129-5p was decreased. Reverse transcription-quantitative polymerase chain reaction (qRT-PCR) was performed to detect the expression level of miR-129-5p in H9c2 cells. In addition, the expression of miR-129-5p and ATG14 were overexpressed or down-regulated after transfection. The transfection efficiency was verified by qRT-PCR. Cell viability, cell apoptosis, and the expression of autophagy and apoptosis-related proteins were determined by CCK-8, flow cytometry and western blotting, respectively. Furthermore, GFP fusion protein analysis was used to detect the expression level of LC3II which was related to autophagy. As a result, cell viability was decreased and cell autophagy was increased in H₂O₂-induced H9c2 cells. MiR-129-5p overexpression inhibited cell injury caused by H₂O₂ in H9c2 cells which was certified by the increased cell viability and decreased cell autophagy and apoptosis. In addition, ATG14 was demonstrated to be a target of miR-129-5p which inhibited cell injury by down-regulation of ATG14. Moreover, phosphorylation of PI3K/AKT/mTOR pathway was activated by miR-129-5p overexpression or ATG14 inhibition to alleviate the autophagy and apoptosis in H₂O₂-induced H9c2 cells. In conclusion, this study indicated that miR-129-5p inhibited autophagy and apoptosis in H₂O₂-induced H9c2 cells partly by down-regulation of ATG14 through the activation of PI3K/AKT/mTOR pathway.

Diethylstilbestrol (DES) induces autophagy in thymocytes by regulating Beclin-1 expression through epigenetic modulation

Diethylstilbestrol (DES) is an endocrine disruptor that was used to prevent adverse effects of pregnancy in women in late 1940s until early 1970s. Its use was banned following significant toxicity and negative effects not only in the mothers but also transgenerationally. Previous studies from our laboratory showed that DES induces thymic atrophy and immunosuppression in mice. In this study, we investigated the molecular mechanisms through which DES triggers thymic atrophy, specifically autophagy. To that end, we treated C57BL/6 mice with DES, and determined expression of two autophagy-related proteins, microtubule-associated protein-1 light chain 3 (LC3) and Beclin-1 (Becn1). We observed that DES-induced thymic atrophy was associated with increased autophagy in thymocytes and significant upregulation in the expression of both Becn1 and LC3. DES also caused downregulation in the expression of miR-30a in thymocytes, and transfection studies revealed that miR-30a targeted Becn1. Upon examination of methylation status of Becn1, we noted hypomethylation of Becn1 in thymocytes of mice exposed to DES. Together, these data demonstrate for the first time that DES induces autophagy in thymocytes potentially through epigenetic changes involving hypomethylation of Becn1 and down-regulation of miR-30a expression.

MicroRNA-30a increases the chemosensitivity of U251 glioblastoma cells to temozolomide by directly targeting beclin 1 and inhibiting autophagy

Temozolomide (TMZ) is one of the most commonly used drugs for the clinical treatment of glioblastomas. However, it has been reported that treatment with TMZ can induce autophagy, which leads to tumor resistance and increases the survival of tumor cells. MicroRNA-30a (miR-30a) has been found to have inhibitory effects on autophagy by directly targeting beclin 1. However, the exact role of miR-30a in TMZ-treated glioblastoma cells has not been studied previously. The present study aimed to investigate whether miR-30a increased the cytotoxicity of TMZ to glioblastoma U251 cells, as well as the underlying mechanism. MTT and flow cytometry assay results showed that treatment with TMZ inhibited the proliferation of U251 cells while inducing cell apoptosis in a dose-dependent manner. Western blotting data showed that the expression levels of LC3-II and beclin 1 as well as the ratio of LC3-II to LC3-I were markedly increased in TMZ-treated U251 cells compared with the untreated control cells, indicating that treatment with TMZ induced autophagy. Moreover, reverse transcription-quantitative polymerase chain reaction data showed that treatment with TMZ led to a significant reduction in miR-30a levels in a dose-dependent manner in U251 cells. Elevation of the miR-30a level significantly inhibited TMZ-induced autophagy, demonstrated by the decreased LC3-II and beclin 1 levels and ratio of LC3-II to LC3-I, accompanied by the reduced proliferation and increased apoptosis in TMZ-treated U251 cells. Furthermore, luciferase reporter assay data indicated that beclin 1 was a direct target of miR-30a in U251 cells. In summary, this study demonstrated that miR-30a increases the chemosensitivity of glioblastoma U251 cells to temozolomide by directly targeting beclin 1 and inhibiting autophagy. Therefore, autophagy may be a promising target for the treatment of TMZ-resistant tumors.

New and revisited approaches to preserving the reperfused myocardium

Early coronary artery reperfusion improves outcomes for patients with ST-segment elevation myocardial infarction (STEMI), but morbidity and mortality after STEMI remain unacceptably high. The primary deficits seen in these patients include inadequate pump function, owing to rapid infarction of muscle in the first few hours of treatment, and adverse remodelling of the heart in the months that follow. Given that attempts to further reduce myocardial infarct size beyond early reperfusion in clinical trials have so far been disappointing, effective therapies are still needed to protect the reperfused myocardium. In this Review, we discuss several approaches to preserving the reperfused heart, such as therapies that target the mechanisms involved in mitochondrial bioenergetics, pyroptosis, and autophagy, as well as treatments that harness the cardioprotective properties of inhaled anaesthetic agents. We also discuss potential therapies focused on correcting the no-reflow phenomenon and its effect on healing and adverse left ventricular remodelling.

MicroRNA-199a acts as a potential suppressor of cardiomyocyte autophagy through targeting Hspa5

Autophagy is an adaptive response to cardiomyocytes survival under stress conditions. MicroRNAs (miRNAs, miR) have been described to act as potent modulators of autophagy. To investigate whether and how miR-199a modulated autophagy in vitro, primary cardiomyocytes were treated under starvation to induce autophagy. Results showed that down-regulation of miR-199a was sufficient to activate cardiomyocytes autophagy. MiR-199a suppressed cardiomyocytes autophagy through direct inhibiting heat shock protein family A member 5 (Hspa5). Forced overexpression of Hspa5 recovered the inhibitory effect of miR-199a in autophagy activation. Our results suggested miR-199a as an effective suppressor of starvation-induced cardiomyocytes autophagy and that Hspa5 was a direct target during this process. These results extend the understanding of the role and pathway of miR-199a in cardiomyocytes autophagy, and may introduce a potential therapeutic strategy for the protection of cardiomyocytes in myocardial infarction or ischemic heart disease.

The role of autophagy in angiotensin II-induced pathological cardiac hypertrophy

Pathological cardiac hypertrophy is associated with nearly all forms of heart failure. It develops in response to disorders such as coronary artery disease, hypertension and myocardial infarction. Angiotensin II (Ang II) has direct effects on the myocardium and promotes hypertension. Chronic elevation of Ang II can lead to pathological cardiac hypertrophy and cardiac failure. Autophagy is an important process in the pathogenesis of cardiovascular diseases. Under physiological conditions, autophagy is an essential homeostatic mechanism to maintain the global cardiac structure function by ridding damaged cells or unwanted macromolecules and organelles. Dysregulation of autophagy may play an important role in Ang II-induced cardiac hypertrophy although conflicting reports on the effects of Ang II on autophagy and cardiac hypertrophy exist. Some studies showed that autophagy activation attenuated Ang II-induced cardiac dysfunction. Others suggested that inhibition of the Ang II induced autophagy should be protective. The discrepancies may be due to different model systems and different signaling pathway involved. Ang II-induced cardiac hypertrophy may be alleviated through regulation of autophagy. This review focuses on Ang II to highlight the molecular targets and pathways identified in the prevention and treatment of Ang II-induced pathological cardiac hypertrophy by regulating autophagy.

Salvianolic acid B induced upregulation of miR-30a protects cardiac myocytes from ischemia/reperfusion injury

BACKGROUND

MicroRNAs (miRNAs) are a novel class of powerful, endogenous regulators of gene expression. This study was designed to ascertain if miR-30a is involved in the cardioprotective actions of salvianolic acid B (Sal B) against myocardial ischemia-reperfusion (I-R) injury through suppression of autophagy.

METHODS

Murine myocardial cells that had undergone primary culture were induced by I-R and incubated with Sal B (25, 50, 100 μM) in the presence of a miR-30a mimic or miR-30a inhibitor. Expression of miR-30a, beclin-1, LC3-II and p-Akt protein, cell viability, and lactic acid dehydrogenase (LDH) release were assessed.

RESULTS

miR-30a expression was down-regulated remarkably in I-R cells, and this suppression could be reversed by Sal B in a dose-dependent manner. Sal B repressed autophagy in I-R myocardial cells. Sal B improved cell viability and reduced the rate of LDH leakage, which suggested that autophagy suppression was beneficial for cell survival. Knockdown of miR-30a with a miR-30a inhibitor could reverse the anti-autophagy effect of Sal B against I-R injury. Furthermore, we confirmed that Sal B has a protective role in miR-30a-mediated autophagy through the PI3K/Akt signaling pathway, which was abrogated by the PI3K inhibitor LY294002.

CONCLUSIONS

These data suggest that miR-30a is involved in Sal B-mediated cardioprotection against I-R injury through the PI3K/Akt signaling pathway.