Inhibition of MicroRNA-146a and Overexpression of Its Target Dihydrolipoyl Succinyltransferase Protect Against Pressure Overload-Induced Cardiac Hypertrophy and Dysfunction

Identification of diagnostic signature and immune infiltration for ischemic cardiomyopathy based on cuproptosis-related genes through bioinformatics analysis and experimental validation

BACKGROUND

Ischemic cardiomyopathy (IC) is primarily due to long-term ischemia/hypoxia of the coronary arteries, leading to impaired cardiac contractile or diastolic function. A new form of cell death induced by copper, called "cuproptosis" is related to the development and progression of multiple diseases. The cuproptosis-related gene (CuGs) plays an important role in acute myocardial infarction, while the specific mechanisms of CuGs in ischemic cardiomyopathy remain unclear.

METHODS

The expressions of CuGs and their immune characteristics were analyzed with the IC datasets obtained from the Gene Expression Omnibus, namely GSE5406 and GSE57338, identifying core genes associated with IC development. By comparing RF, SVM, GLM and XGB models, the optimal machine learning model was selected. The expression of marker genes was validated based on the GSE57345, GSE48166 and GSE42955 datasets. Construct a CeRNA network based on core genes. Therapeutic chemiacals targeting core genes were acquired using the CTD database, and molecular docking was performed using Autodock vina software. By ligating the left anterior descending (LAD) coronary artery, an IC mouse model is established, and core genes were experimentally validated using Western blot (WB) and immunohistochemistry (IHC) methods.

RESULTS

We identified 14 CuGs closely associated with the onset of IC. The SVM model exhibited superior discriminative power (AUC = 0.914), with core genes being DLST, ATP7B, FDX1, SLC31A1 and DLAT. Core genes were validated on the GSE42955, GSE48166 and GSE57345 datasets, showing excellent performance (AUC = 0.943, AUC = 0.800, and AUC = 0.932). The CeRNA network consists of 218 nodes and 264 lines, including 5 core diagnostic genes, 52 miRNAs, and 161 lncRNAs. Chemicals predictions indicated 8 chemicals have therapeutic effects on the core diagnostic genes, with benzo(a)pyrene molecular docking showing the highest affinity (-11.3 kcal/mol). Compared to the normal group, the IC group,which was established by LAD ligation, showed a significant decrease in LVEF as indicated by cardiac ultrasound, and increased fibrosis as shown by MASSON staining, WB results suggest increased expression of DLST and ATP7B, and decreased expression of FDX1, SLC31A1 and DLAT in the myocardial ischemic area (p < 0.05), which was also confirmed by IHC in tissue sections.

CONCLUSION

In summary, this study comprehensively revealed that DLST, ATP7B, FDX1, SLC31A1 and DLAT could be identified as potential immunological biomarkers in IC, and validated through an IC mouse model, providing valuable insights for future research into the mechanisms of CuGs and its diagnostic value to IC.

Unraveling the Impact of miR-146a in Pulmonary Arterial Hypertension Pathophysiology and Right Ventricular Function

Pulmonary arterial hypertension (PAH) is a chronic disorder characterized by excessive pulmonary vascular remodeling, leading to elevated pulmonary vascular resistance and right ventricle (RV) overload and failure. MicroRNA-146a (miR-146a) promotes vascular smooth muscle cell proliferation and vascular neointimal hyperplasia, both hallmarks of PAH. This study aimed to investigate the effects of miR-146a through pharmacological or genetic inhibition on experimental PAH and RV pressure overload animal models. Additionally, we examined the overexpression of miR-146a on human pulmonary artery smooth muscle cells (hPASMCs). Here, we showed that miR-146a genic expression was increased in the lungs of patients with PAH and the plasma of monocrotaline (MCT) rats. Interestingly, genetic ablation of miR-146a improved RV hypertrophy and systolic pressures in Sugen 5415/hypoxia (SuHx) and pulmonary arterial banding (PAB) mice. Pharmacological inhibition of miR-146a improved RV remodeling in PAB-wild type mice and MCT rats, and enhanced exercise capacity in MCT rats. However, overexpression of miR-146a did not affect proliferation, migration, and apoptosis in control-hPASMCs. Our findings show that miR-146a may play a significant role in RV function and remodeling, representing a promising therapeutic target for RV hypertrophy and, consequently, PAH.

Single dose of intravenous miR199a-5p delivery targeting ischemic heart for long-term repair of myocardial infarction

Long-term treatment of myocardial infarction is challenging despite medical advances. Tissue engineering shows promise for MI repair, but implantation complexity and uncertain outcomes pose obstacles. microRNAs regulate genes involved in apoptosis, angiogenesis, and myocardial contraction, making them valuable for long-term repair. In this study, we find downregulated miR-199a-5p expression in MI. Intramyocardial injection of miR-199a-5p into the infarcted region of male rats revealed its dual protective effects on the heart. Specifically, miR-199a-5p targets AGTR1, diminishing early oxidative damage post-myocardial infarction, and MARK4, which influences long-term myocardial contractility and enhances cardiac function. To deliver miR-199a-5p efficiently and specifically to ischemic myocardial tissue, we use CSTSMLKAC peptide to construct P-MSN/miR199a-5p nanoparticles. Intravenous administration of these nanoparticles reduces myocardial injury and protects cardiac function. Our findings demonstrate the effectiveness of P-MSN/miR199a-5p nanoparticles in repairing MI through enhanced contraction and anti-apoptosis. miR199a-5p holds significant therapeutic potential for long-term repair of myocardial infarction.

MicroRNA-146a Signature in Psoriasis: A Systematic Review and Meta-Analysis

BACKGROUND

Psoriasis is a chronic, inflammatory, T-cell-mediated disease with a multifactorial pathogenesis. MicroRNA (miRNA) alteration in psoriasis has been identified within the last few years. In particular, miR-146a levels were altered. However, previous studies have equivocal or even contradictory findings.

OBJECTIVE

The current study aimed to perform a systematic review and meta-analysis to evaluate the miRNA expression profile in different tissues in patients with psoriasis. Further, the correlation between miR-146a levels and psoriasis severity as well as the specific expression patterns of the miR-146a profile in patients with psoriasis after treatment were evaluated.

METHODS

To retrieve studies investigating the correlation between miRNA and psoriasis, a comprehensive search of databases including PubMed, Cochrane Library, and Embase was performed from inception to 30 June 2023. Relevant journals and references of the included studies were also reviewed. A meta-analysis was conducted using the comprehensive meta-analysis version 3.

RESULTS

The correlation between the miR-146a expression levels and psoriasis susceptibility in 14 studies was assessed. Results showed that the miR-146a expression level was upregulated in psoriasis samples [P = 0.001, standardized mean difference (SMD) = 1.489, 95% confidence interval (CI) = 0.618-2.360]. In a subgroup analysis based on sample type, the correlation between the peripheral blood mononuclear cell, blood, and tissue miR-146a expression level and psoriasis was significant (SMD = 1.293, 95% CI 0.310-2.276, P = 0.01; SMD = 2.526, 95% CI 1.710-3.342, P = 0.000; SMD = 3.153, 95% CI 1.432-4.874, P = 0.00, respectively). A positive correlation was observed between the miR-146a expression levels and Psoriasis Area and Severity Index (PASI) score. However, the result was not statistically significant (correlation coefficient = 0.29, 95% CI - 0.038 to 0.575, P = 0.081). Further, the miR-146a levels decreased after treatment (SMD = - 1.592, 95% CI - 2.067 to - 1.117, P = 0.000, I2 = 74.104).

CONCLUSIONS

The miR-146a expression level is positively correlated with and can contribute to the pathobiology of psoriasis.

Genetic Mutations and Mitochondrial Redox Signaling as Modulating Factors in Hypertrophic Cardiomyopathy: A Scoping Review

Hypertrophic cardiomyopathy (HCM) is a heart condition characterized by cellular and metabolic dysfunction, with mitochondrial dysfunction playing a crucial role. Although the direct relationship between genetic mutations and mitochondrial dysfunction remains unclear, targeting mitochondrial dysfunction presents promising opportunities for treatment, as there are currently no effective treatments available for HCM. This review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews guidelines. Searches were conducted in databases such as PubMed, Embase, and Scopus up to September 2023 using "MESH terms". Bibliographic references from pertinent articles were also included. Hypertrophic cardiomyopathy (HCM) is influenced by ionic homeostasis, cardiac tissue remodeling, metabolic balance, genetic mutations, reactive oxygen species regulation, and mitochondrial dysfunction. The latter is a common factor regardless of the cause and is linked to intracellular calcium handling, energetic and oxidative stress, and HCM-induced hypertrophy. Hypertrophic cardiomyopathy treatments focus on symptom management and complication prevention. Targeted therapeutic approaches, such as improving mitochondrial bioenergetics, are being explored. This includes coenzyme Q and elamipretide therapies and metabolic strategies like therapeutic ketosis. Understanding the biomolecular, genetic, and mitochondrial mechanisms underlying HCM is crucial for developing new therapeutic modalities.

Integrative analysis of bioinformatics and machine learning to identify cuprotosis-related biomarkers and immunological characteristics in heart failure

Backgrounds

Cuprotosis is a newly discovered programmed cell death by modulating tricarboxylic acid cycle. Emerging evidence showed that cuprotosis-related genes (CRGs) are implicated in the occurrence and progression of multiple diseases. However, the mechanism of cuprotosis in heart failure (HF) has not been investigated yet.

Methods

The HF microarray datasets GSE16499, GSE26887, GSE42955, GSE57338, GSE76701, and GSE79962 were downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed CRGs between HF patients and nonfailing donors (NFDs). Four machine learning models were used to identify key CRGs features for HF diagnosis. The expression profiles of key CRGs were further validated in a merged GEO external validation dataset and human samples through quantitative reverse-transcription polymerase chain reaction (qRT-PCR). In addition, Gene Ontology (GO) function enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and immune infiltration analysis were used to investigate potential biological functions of key CRGs.

Results

We discovered nine differentially expressed CRGs in heart tissues from HF patients and NFDs. With the aid of four machine learning algorithms, we identified three indicators of cuprotosis (DLAT, SLC31A1, and DLST) in HF, which showed good diagnostic properties. In addition, their differential expression between HF patients and NFDs was confirmed through qRT-PCR. Moreover, the results of enrichment analyses and immune infiltration exhibited that these diagnostic markers of CRGs were strongly correlated to energy metabolism and immune activity.

Conclusions

Our study discovered that cuprotosis was strongly related to the pathogenesis of HF, probably by regulating energy metabolism-associated and immune-associated signaling pathways.

The role of lncRNAKCNQ1OT1/miR-301b/Tcf7 axis in cardiac hypertrophy

OBJECTIVE

Cardiac hypertrophy, acting as a pathologic process of chronic hypertension and coronary disease, and its underlying mechanisms still need to be explored. Long non-coding RNA (LncRNA) potassium voltage-gated channel subfamily Q member 1 Transcript 1 (KCNQ1OT1) has been implicated in myocardial infarction. However, its role in cardiac hypertrophy remains reported.

METHOD

To explore the regulated effect of lncRNAKCNQ1OT1 and miR-301b in cardiac hypertrophy, gain-and-lose function assays were tested. The expression of lncRNAKCNQ1OT1 and miR-301b were tested by quantitative real time polymerase chain reaction (qRT-PCR). The levels of transcription factor 7 (Tcf7), Proto-oncogene c-myc (c-myc), Brainnatriureticpeptide (BNP) and β-myosin heavy chain (β-MHC) were detected by Western blot. Additionally, luciferase analysis revealed interaction between lncRNAKCNQ1OT1, BNPβ-MHCmiR-301b, and Tcf7.

RESULT

LncRNAKCNQ1OT1 overexpression significantly induced cardiac hypertrophy. Furthermore, lncRNAKCNQ1OT1 acts as a sponge for microRNA-301b, which exhibited lower expression in cardiac hypertrophy model, indicating an anti-hypertrophic role. Furthermore, the BNP and β-MHC expression increased, as well as cardiomyocyte surface area, with Ang II treatment, while the effect was repealed by miR-301b. Moreover, the protein expression of Tcf7 was inversely regulated by miR-301b and Antisense miRNA oligonucleotides (AMO)-301b.

CONCLUSION

Our study has shown that overexpression of lncRNAKCNQ1OT1 could promote the development of cardiac hypertrophy by regulating miR-301b and Tcf7. Therefore, inhibition of lncRNAKCNQ1OT1 might be a potential therapeutic strategy for cardiac hypertrophy.

Recent advances in mechanistic studies of heart failure with preserved ejection fraction and its comorbidities-Role of microRNAs

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a multifaceted syndrome with a complex aetiology commonly associated with comorbidities such as diabetes mellitus, obesity, hypertension and renal disease. Various diseases induce systemic, chronic and low-grade inflammation; microvascular dysfunction; metabolic stress; tissue ischemia; and fibrosis, leading to HFpEF. An effective treatment for HFpEF is lacking, largely owing to its pathophysiological heterogeneity. Recent studies have revealed that microRNAs (miRNAs) play crucial roles in regulating the pathogenesis of HFpEF and its comorbidities.

METHODS

This narrative review included original articles and reviews published over the past 20 years found through 'PubMed' and 'Web of Science'. The search terms included "HFpEF," "MicroRNAs," "comorbidities," "Microvascular Dysfunction (MVD)," "inflammation," "pathophysiology," "endothelial dysfunction," "energy metabolism abnormalities" "cardiac fibrosis" and "treatment."

RESULTS

Inflammation, MVD, abnormal energy metabolism, myocardial hypertrophy and myocardial fibrosis are important pathophysiological mechanisms underlying HFpEF. As gene expression regulators, miRNAs may contribute to the pathophysiology of HFpEF and are expected to serve in the stratification of patients with HFpEF and as prognostic indicators for monitoring treatment responses.

CONCLUSIONS

A customized strategy based on miRNAs has emerged as an effective treatment for HFpEF. In this review, we discuss recent research surrounding miRNAs and HFpEF and propose potential miRNA targets for the pathophysiology of HFpEF and its comorbidities. Although current research concerning miRNAs and their therapeutic potential is in its early stages, miRNA-based diagnostics and therapeutics hold great promise in the future.

Cardiovascular aging: spotlight on mitochondria

Mitochondria are cellular organelles critical for ATP production and are particularly relevant to cardiovascular diseases including heart failure, atherosclerosis, ischemia-reperfusion injury, and cardiomyopathies. With advancing age, even in the absence of clinical disease, mitochondrial homeostasis becomes disrupted (e.g., redox balance, mitochondrial DNA damage, oxidative metabolism, and mitochondrial quality control). Mitochondrial dysregulation leads to the accumulation of damaged and dysfunctional mitochondria, producing excessive reactive oxygen species and perpetuating mitochondrial dysfunction. In addition, mitochondrial DNA, cardiolipin, and N-formyl peptides are potent activators of cell-intrinsic and -extrinsic inflammatory pathways. These age-related mitochondrial changes contribute to the development of cardiovascular diseases. This review covers the impact of aging on mitochondria and links these mechanisms to therapeutic implications for age-associated cardiovascular diseases.

MYOD induced lnc-MEG3 promotes porcine satellite cell differentiation via interacting with DLST

Long non-coding RNAs (lncRNAs) are involved in the process of muscle cell differentiation and play an important role. Previous studies have shown that lncRNA-MEG3 promotes the differentiation of porcine skeletal muscle satellite cells (PSCs), but the regulatory mechanism of MEG3 interaction with target protein has not been well studied. We demonstrated that MEG3 can bind dihydrolipoamide succinyltransferase (DLST) by RNA pull down and RIP-qPCR. Subsequently, knockdown and overexpression experiments showed that DLST promotes PSCs differentiation. Rescue experiments showed that the expression of DLST protein was significantly increased with MEG3 overexpression and decreased with MEG3 knockdown, while its mRNA expression was not changed. Furthermore, we have successfully predicted and validated that the transcription factor myogenic differentiation (MYOD) binds to the MEG3 core promoter though utilizing chromatin immunoprecipitation (CHIP) and luciferase reporter assays. The results indicated that MYOD acts as a transcription factor of MEG3 to promote MEG3 transcription. Knockdown of MEG3 in vivo indicated that MEG3 is involved in skeletal muscle regeneration. It is concluded that MYOD acts as a transcription factor to induce MEG3 expression. MEG3 acts as a molecular scaffold to bind and promote DLST protein expression. This paper provides a new molecular mechanism for MEG3 to promote the differentiation of PSCs.

MicroRNA-146a Promotes Embryonic Stem Cell Differentiation towards Vascular Smooth Muscle Cells through Regulation of Kruppel-like Factor 4

OBJECTIVE

Vascular smooth muscle cell (VSMC) differentiation from stem cells is one source of the increasing number of VSMCs that are involved in vascular remodeling-related diseases such as hypertension, atherosclerosis, and restenosis. MicroRNA-146a (miR-146a) has been proven to be involved in cell proliferation, migration, and tumor metabolism. However, little is known about the functional role of miR-146a in VSMC differentiation from embryonic stem cells (ESCs). This study aimed to determine the role of miR-146a in VSMC differentiation from ESCs.

METHODS

Mouse ESCs were differentiated into VSMCs, and the cell extracts were analyzed by Western blotting and RT-qPCR. In addition, luciferase reporter assays using ESCs transfected with miR-146a/mimic and plasmids were performed. Finally, C57BL/6J female mice were injected with mimic or miR-146a-overexpressing ESCs, and immunohistochemistry, Western blotting, and RT-qPCR assays were carried out on tissue samples from these mice.

RESULTS

miR-146a was significantly upregulated during VSMC differentiation, accompanied with the VSMC-specific marker genes smooth muscle-alpha-actin (SMαA), smooth muscle 22 (SM22), smooth muscle myosin heavy chain (SMMHC), and h1-calponin. Furthermore, overexpression of miR-146a enhanced the differentiation process in vitro and in vivo. Concurrently, the expression of Kruppel-like factor 4 (KLF4), predicted as one of the top targets of miR-146a, was sharply decreased in miR-146a-overexpressing ESCs. Importantly, inhibiting KLF4 expression enhanced the VSMC-specific gene expression induced by miR-146a overexpression in differentiating ESCs. In addition, miR-146a upregulated the mRNA expression levels and transcriptional activity of VSMC differentiation-related transcription factors, including serum response factor (SRF) and myocyte enhancer factor 2c (MEF-2c).

CONCLUSION

Our data support that miR-146a promotes ESC-VSMC differentiation through regulating KLF4 and modulating the transcription factor activity of VSMCs.

Myocardial angiogenesis induced by concurrent vitamin D supplementation and aerobic-resistance training is mediated by inhibiting miRNA-15a, and miRNA-146a and upregulating VEGF/PI3K/eNOS signaling pathway

This study aimed to investigate the effects of co-treatment of aerobic-resistance training (ART), vitamin D₃ (VD₃) on cardiovascular function considering the involvement of microRNA-15a and microRNA-146a, vascular endothelial growth factor (VEGF), phosphatidylinositol-3 kinase (PI3K), and endothelial nitric oxide synthase (eNOS) after myocardial infarction (MI) in rats. To induce MI, male Wistar rats subcutaneously received isoproterenol for 2 days, then MI was confirmed by echocardiography. MI rats were divided into six groups (n = 8/group). MI + VD₃, MI + sesame oil (Veh), MI + ART, MI + VD₃ + ART, and MI + Veh + ART, and received the related treatments for 8 weeks. Exercise tests, echocardiography, real-time quantitative polymerase chain reaction (qRT-PCR), western blotting, and histological staining were performed after the end of treatments. The highest ejection fraction (EF%), fractional shortening (FS%), exercise capacity (EC), and maximal load test (MLT) amounts were observed in the groups treated with VD₃, ART, and VD₃ + ART (P < 0.05). These were accompanied by a significantly increased angiogenesis post-MI. Furthermore, the levels of circulating microRNA-15a and microRNA-146a were significantly decreased in these groups compared to MI rats that were together with a significant upregulation of cardiac VEGF, PI3K, and eNOS expression. Overall, the best results were observed in the group treated with VD₃ + ART. Concurrent VD₃ supplementation and ART attenuated microRNA-15a and microRNA-146a and induced angiogenesis via VEGF/PI3K/eNOS axis. This data demonstrate that concurrent VD₃ supplementation and ART is a more efficient strategy than monotherapy to improve cardiac function post-MI.

Grpel2 maintains cardiomyocyte survival in diabetic cardiomyopathy through DLST-mediated mitochondrial dysfunction: a proof-of-concept study

BACKGROUND

Diabetic cardiomyopathy (DCM) has been considered as a major threat to health in individuals with diabetes. GrpE-like 2 (Grpel2), a nucleotide exchange factor, has been shown to regulate mitochondrial import process to maintain mitochondrial homeostasis. However, the effect and mechanism of Grpel2 in DCM remain unknown.

METHODS

The streptozotocin (STZ)-induced DCM mice model and high glucose (HG)-treated cardiomyocytes were established. Overexpression of cardiac-specific Grpel2 was performed by intramyocardial injection of adeno-associated virus serotype 9 (AAV9). Bioinformatics analysis, co-immunoprecipitation (co-IP), transcriptomics profiling and functional experiments were used to explore molecular mechanism of Grpel2 in DCM.

RESULTS

Here, we found that Grpel2 was decreased in DCM induced by STZ. Overexpression of cardiac-specific Grpel2 alleviated cardiac dysfunction and structural remodeling in DCM. In both diabetic hearts and HG-treated cardiomyocytes, Grpel2 overexpression attenuated apoptosis and mitochondrial dysfunction, including decreased mitochondrial ROS production, increased mitochondrial respiratory capacities and increased mitochondrial membrane potential. Mechanistically, Grpel2 interacted with dihydrolipoyl succinyltransferase (DLST), which positively mediated the import process of DLST into mitochondria under HG conditions. Furthermore, the protective effects of Grpel2 overexpression on mitochondrial function and cell survival were blocked by siRNA knockdown of DLST. Moreover, Nr2f6 bond to the Grpel2 promoter region and positively regulated its transcription.

CONCLUSION

Our study provides for the first time evidence that Grpel2 overexpression exerts a protective effect against mitochondrial dysfunction and apoptosis in DCM by maintaining the import of DLST into mitochondria. These findings suggest that targeting Grpel2 might be a promising therapeutic strategy for the treatment of patients with DCM.

Proteomic analysis revealed the pharmacological mechanism of Xueshuantong injection in preventing early acute myocardial infarction injury

Background: Acute myocardial infarction (AMI) is a common and life-threatening cardiovascular disease. However, there is a lack of pathology and drug studies on AMI within 20 min. Xueshuantong injection (XST) is mainly composed of Panax notoginseng saponins, which can dilate blood vessels and improve blood circulation, and is clinically used in the treatment of cardiovascular and cerebrovascular diseases. Purpose: The study aimed to investigate the protective mechanism of Xueshuantong injection against acute myocardial infarction within 20 min in rats by proteomic methods and molecular docking. Method: The male Sprague-Dawley rat acute myocardial infarction model was established by LAD ligation, and Xueshuantong injection (38 mg/kg) was injected into the caudal vein 15 min before surgery. Cardiac function evaluation, morphological observation, label-free quantitative proteomics, Western blotting analysis, molecular docking, and affinity measurement were applied in this study. Results: In a span of 20 min after acute myocardial infarction, the model group showed significant cardiac function impairment. Xueshuantong injection can significantly improve cardiac function and prevent pathological injury of myocardial tissue. A total of 117 vital differentially expressed proteins were identified by proteomic analysis, including 80 differentially expressed proteins (DEPs) in the sham group compared with model rats (Sham: model) and 43 DEPs in model rats compared with the Xueshuantong injection group (Model: XST). The treatment of Xueshuantong injection mainly involves "poly(A) RNA binding" and "cadherin binding involved in cell-cell adhesion." The differentially expressed levels of the pathways related to proteins Echdc2, Gcdh, Dlst, and Nampt, as well as 14-3-3 family proteins Ywhaz and Ywhab, could be quantitatively confirmed by WB. Molecular docking analysis and SPR analysis revealed that Ywhaz has a generally stable binding with five Xueshuantong injection components. Conclusion: Xueshuantong injection (XST) could protect rat myocardial function injury against AMI in 20 min. Echdc2, Ywhaz, Gcdh, Ywhab, Nampt, and Dlst play an essential role in this protective effect. In particular, Ywhaz might be the core target of Xueshuantong injection when treating acute myocardial infarction in the early stage. This study promoted the understanding of the protective mechanism of Xueshuantong injection in 20 min injury of acute myocardial infarction and contributed to the identification of possible targets of Xueshuantong injection.

Stem cell‐derived extracellular vesicles reduce the expression of molecules involved in cardiac hypertrophy—In a model of human-induced pluripotent stem cell-derived cardiomyocytes

Cardiac pathological hypertrophy is the major risk factor that usually progresses to heart failure. We hypothesized that extracellular vesicles (EVs), known to act as important mediators in regulating physiological and pathological functions, could have the potential to reduce the cardiac hypertrophy and the ensuing cardiovascular diseases. Herein, the effects of mesenchymal stem cell-derived extracellular vesicles (EV-MSCs) on cardiac hypertrophy were investigated. EVs were isolated from the secretome of human adipose tissue-derived stem cells (EV-ADSCs) or bone marrow-derived stem cells (EV-BMMSCs). Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were stimulated with AngII and TGF-β1, in absence or presence of EVs. The results showed that exposure of hiPSC-CMs to AngII and TGF-β1 generated in vitro model of hypertrophic cardiomyocytes characterized by increases in surface area, reactive oxygen species production, protein expression of cardiac-specific biomarkers atrial natriuretic factor, migration inhibitory factor, cTnI, COL1A1, Cx43, α-SMA and signalling molecules SMAD2 and NF-kBp50. The presence of EV-ADSCs or EV-BMMSCs in the hiPSC-CM culture along with hypertrophic stimuli reduced the protein expressions of hypertrophic specific markers (ANF, MIF, cTnI, COL1A1) and the gene expressions of IL-6 molecule involved in inflammatory process associated with cardiac hypertrophy and transcription factors SMAD2, SMAD3, cJUN, cFOS with role in cardiomyocyte hypertrophic response induced by AngII and TGF-β1. The EV-ADSCs were more effective in reducing the protein expressions of hypertrophic and inflammatory markers, while EV-BMMSCs in reducing the gene expressions of transcription factors. Notably, neither EV-ADSCs nor EV-BMMSCs induced significant changes in cardiac biomarkers Cx43, α-SMA and fibronectin. These different effects of stem cell-derived EVs could be attributed to their miRNA content: some miRNAs (miR-126-3p, miR-222-3p, miR-30e-5p, miR-181b-5p, miR-124-3p, miR-155-5p, miR-210-3p hsa-miR-221-3p) were expressed in both types of EVs and others only in EV-ADSCs (miR-181a-5p, miR-185-5p, miR-21-5p) or in EV-BMMSCs (miR-143-3p, miR-146a-5p, miR-93-5p), some of these attenuating the cardiac hypertrophy while others enhance it. In conclusion, in hiPSC-CMs the stem cell-derived EVs through their cargo reduced the expression of hypertrophic specific markers and molecules involved in inflammatory process associated with cardiac hypertrophy. The data suggest the EV potential to act as therapeutic mediators to reduce cardiac hypertrophy and possibly the subsequent cardiovascular events.

Metabolic characterization of hypertrophic cardiomyopathy in human heart

Hypertrophic cardiomyopathy (HCM) is a common inherited cardiovascular disease with heterogeneous clinical presentations, governed by multiple molecular mechanisms. Metabolic perturbations underlie most cardiovascular diseases; however, the metabolic alterations and their function in HCM are unknown. Here, we describe the metabolome and lipidome of heart and plasma samples from individuals with and without HCM. Correlation analyses showed strong association between metabolic alterations and cardiac function and prognosis of patients with HCM. Using machine learning we identified metabolite panels as potential HCM diagnostic markers or predictors of survival. Clustering based on metabolome and lipidome of heart enabled stratification of patients with HCM into three subgroups with distinct cardiac function and survival. Integration of metabolomics and proteomics data identified metabolic pathways significantly altered in patients with HCM, with the pentose phosphate pathway and oxidative stress being particularly upregulated. Thus, targeting the pentose phosphate pathway and oxidative stress may serve as potential therapeutic strategies for HCM.

Circular RNA circ_0001006 aggravates cardiac hypertrophy via miR-214-3p/PAK6 axis

AIM

Circular RNAs (circRNAs) control gene expression in a series of physiological and pathological processes, but their role in heart disease is unknown. This research illustrates the role and potential mechanism of circRNA in cardiac hypertrophy.

METHODS AND RESULTS

In this report, we found that circular RNA hsa_circ_0001006 (circ_0001006) was upregulated in cardiac hypertrophy mice and cardiomyocytes treated with angiotensin II (Ang II). Next, we noticed that gain of function circ_0001006 could induce cardiomyocyte hypertrophy; oppositely, knockdown of circ_0001006 remitted Ang II-induced cardiomyocyte hypertrophy. Biotin-coupled miRNA and RNA-pull down assays showed that miR-214-3p could bind with circ_0001006 and gain the function of miR-214-3p abrogated the pro-hypertrophy effect of circ_0001006. Furthermore, Further, dual-luciferase reporter assay showed that miR-214-3p could interact with 3'UTRs of the PAK6 gene, and circRNA_0001006 could block the above interactions. Additionally, PAK6 expression is inhibited by miR-214-3p mimic in cardiomyocytes but enhanced by over-expression of circRNA_000203 in vitro.

CONCLUSIONS

Our data demonstrated that circRNA_0001006 exacerbates cardiac hypertrophy via suppressing miR-214-3p leading to enhanced PAK6 levels.

Research Progress on Epigenetics of Diabetic Cardiomyopathy in Type 2 Diabetes

Diabetic cardiomyopathy (DCM) is characterized by diastolic relaxation abnormalities in its initial stages and by clinical heart failure (HF) without dyslipidemia, hypertension, and coronary artery disease in its last stages. DCM contributes to the high mortality and morbidity rates observed in diabetic populations. Diabetes is a polygenic, heritable, and complex condition that is exacerbated by environmental factors. Recent studies have demonstrated that epigenetics directly or indirectly contribute to pathogenesis. While epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNAs, have been recognized as key players in the pathogenesis of DCM, some of their impacts remain not well understood. Furthering our understanding of the roles played by epigenetics in DCM will provide novel avenues for DCM therapeutics and prevention strategies.

MiRNA-339-5p promotes isoproterenol-induced cardiomyocyte hypertrophy by targeting VCP to activate the mTOR signaling

MicroRNAs (miRNAs) regulate multiple biological processes and participate in various cardiovascular diseases. This study aims to investigate the role of miR-339-5p in cardiomyocyte hypertrophy and the involved mechanism. Neonatal rat cardiomyocytes (NRCMs) were cultured and stimulated with isoproterenol (ISO). The hypertrophic responses were monitored by measuring the cell surface area and expression of hypertrophic markers including β-myosin heavy chain (β-MHC) and atrial natriuretic factor (ANF). Bioinformatic prediction tools and dual-luciferase reporter assay were performed to identify the target gene of miR-339-5p. Quantitative real-time polymerase chain reaction and western blot analysis were used to determine the levels of miR-339-5p and its downstream effectors. Our data showed that miR-339-5p was upregulated during cardiomyocyte hypertrophy triggered by ISO. MiR-339-5p overexpression resulted in enlargement of cell size and increased the levels of hypertrophic markers. In contrast, inhibition of miR-339-5p significantly attenuated ISO-induced hypertrophic responses of NRCMs. Valosin-containing protein (VCP), a suppressor of cardiac hypertrophy via inhibiting mechanistic target of rapamycin (mTOR) signaling, was validated as a target of miR-339-5p. MiR-339-5p suppressed VCP protein expression, leading to elevated phosphorylation of mTOR and ribosomal protein S6 kinase (S6K). VCP depletion activated the mTOR/S6K cascade and could compromise the anti-hypertrophic effects of miR-339-5p inhibitor. Additionally, the hypertrophic responses caused by miR-339-5p was alleviated in the presence of mTOR inhibitor rapamycin. In conclusion, our research revealed that miR-339-5p promoted ISO-induced cardiomyocyte hypertrophy by targeting VCP to activate the mTOR signaling, suggesting a promising therapeutic intervention by interfering miR-339-5p.

Plasma-Derived microRNAs Are Influenced by Acute and Chronic Exercise in Patients With Heart Failure With Reduced Ejection Fraction

Background: Exercise training improves VO2peak in heart failure with reduced ejection fraction (HFrEF), but the effect is highly variable as it is dependent on peripheral adaptations. We evaluated changes in plasma-derived miRNAs by acute and chronic exercise to investigate whether these can mechanistically be involved in the variability of exercise-induced adaptations. Methods: Twenty-five male HFrEF patients (left ventricular ejection fraction < 40%, New York Heart Association class ≥ II) participated in a 15-week combined strength and aerobic training program. The effect of training on plasma miRNA levels was compared to 21 male age-matched sedentary HFrEF controls. Additionally, the effect of a single acute exercise bout on plasma miRNA levels was assessed. Levels of 5 miRNAs involved in pathways relevant for exercise adaptation (miR-23a, miR-140, miR-146a, miR-191, and miR-210) were quantified using RT-qPCR and correlated with cardiopulmonary exercise test (CPET), echocardiographic, vascular function, and muscle strength variables. Results: Expression levels of miR-146a decreased with training compared to controls. Acute exercise resulted in a decrease in miR-191 before, but not after training. Baseline miR-23a predicted change in VO2peak independent of age and left ventricular ejection fraction (LVEF). Baseline miR-140 was independently correlated with change in load at the respiratory compensation point and change in body mass index, and baseline miR-146a with change in left ventricular mass index. Conclusion: Plasma-derived miRNAs may reflect the underlying mechanisms of exercise-induced adaptation. In HFrEF patients, baseline miR-23a predicted VO2peak response to training. Several miRNAs were influenced by acute or repeated exercise. These findings warrant exploration in larger patient populations and further mechanistic in vitro studies on their molecular involvement.

MicroRNA-27b-3p downregulates FGF1 and aggravates pathological cardiac remodelling

AIMS

The heart undergoes pathological remodelling under increased stress and neuronal imbalance. MicroRNAs (miRNAs) are involved in post-transcriptional regulation of genes in cardiac physiology and pathology. However, the mechanisms underlying miRNA-mediated regulation of pathological cardiac remodelling remain to be studied. This study aimed to explore the function of endogenous microRNA-27b-3p (miR-27b-3p) in pathological cardiac remodelling.

METHODS AND RESULTS

miR-27b-3p expression was elevated in the heart of a transverse aortic constriction (TAC)-induced cardiac hypertrophy mouse model. MiR-27b-knockout mice showed significantly attenuated cardiac hypertrophy, fibrosis, and inflammation induced by two independent pathological cardiac hypertrophy models, TAC and Angiotensin II (Ang II) perfusion. Transcriptome sequencing analysis revealed that miR-27b deletion significantly downregulated TAC-induced cardiac hypertrophy, fibrosis, and inflammatory genes. We identified fibroblast growth factor 1 (FGF1) as a miR-27b-3p target gene in the heart and was upregulated in miR-27b-null mice. We found that both recombinant FGF1 (rFGF1) and inhibition of miR-27b-3p enhanced mitochondrial oxidative phosphorylation (OXPHOS) and inhibited cardiomyocyte hypertrophy. Importantly, rFGF1 administration inhibited cardiac hypertrophy and fibrosis in TAC or Ang II-induced models, and enhanced OXPHOS by activating PGC1α/β.

CONCLUSIONS

Our study demonstrated that miR-27b-3p induces pathological cardiac remodelling and suggests that inhibition of endogenous miR-27b-3p or administration of FGF1 might have the potential to suppress cardiac remodelling in a clinical setting.

TRANSLATIONAL PERSPECTIVE

MicroRNAs (miRNAs) are involved in post-transcriptional regulation of genes in cardiac physiology and pathology. However, the mechanisms underlying miRNA-mediated regulation of pathological cardiac remodelling remain to be studied. We show for the first time that miR-27b deletion attenuates cardiac hypertrophy, fibrosis, and inflammation and that rFGF1 administration inhibits cardiac hypertrophy and fibrosis in TAC- or Ang II-induced models, and enhances OXPHOS by activating PGC1α/β. Our findings suggest that miR-27b-3p and FGF1 may be potential therapeutic targets to treat conditions characterised by pathological cardiac remodelling.

Redox signaling in heart failure and therapeutic implications

Heart failure is a growing health burden worldwide characterized by alterations in excitation-contraction coupling, cardiac energetic deficit and oxidative stress. While current treatments are mostly limited to antagonization of neuroendocrine activation, more recent data suggest that also targeting metabolism may provide substantial prognostic benefit. However, although in a broad spectrum of preclinical models, oxidative stress plays a causal role for the development and progression of heart failure, no treatment that targets reactive oxygen species (ROS) directly has entered the clinical arena yet. In the heart, ROS derive from various sources, such as NADPH oxidases, xanthine oxidase, uncoupled nitric oxide synthase and mitochondria. While mitochondria are the primary source of ROS in the heart, communication between different ROS sources may be relevant for physiological signalling events as well as pathologically elevated ROS that deteriorate excitation-contraction coupling, induce hypertrophy and/or trigger cell death. Here, we review the sources of ROS in the heart, the modes of pathological activation of ROS formation as well as therapeutic approaches that may target ROS specifically in mitochondria.

The Role of MicroRNAs in Mitochondria-Mediated Eye Diseases

The retina is among the most metabolically active tissues with high-energy demands. The peculiar distribution of mitochondria in cells of retinal layers is necessary to assure the appropriate energy supply for the transmission of the light signal. Photoreceptor cells (PRs), retinal pigment epithelium (RPE), and retinal ganglion cells (RGCs) present a great concentration of mitochondria, which makes them particularly sensitive to mitochondrial dysfunction. To date, visual loss has been extensively correlated to defective mitochondrial functions. Many mitochondrial diseases (MDs) show indeed neuro-ophthalmic manifestations, including retinal and optic nerve phenotypes. Moreover, abnormal mitochondrial functions are frequently found in the most common retinal pathologies, i.e., glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR), that share clinical similarities with the hereditary primary MDs. MicroRNAs (miRNAs) are established as key regulators of several developmental, physiological, and pathological processes. Dysregulated miRNA expression profiles in retinal degeneration models and in patients underline the potentiality of miRNA modulation as a possible gene/mutation-independent strategy in retinal diseases and highlight their promising role as disease predictive or prognostic biomarkers. In this review, we will summarize the current knowledge about the participation of miRNAs in both rare and common mitochondria-mediated eye diseases. Definitely, given the involvement of miRNAs in retina pathologies and therapy as well as their use as molecular biomarkers, they represent a determining target for clinical applications.

MicroRNAs Regulating Mitochondrial Function in Cardiac Diseases

Mitochondria are the key organelles that supply cellular energy. As the most active organ in the body, the energy required to maintain the mechanical function of the heart requires a high quantity of high-quality mitochondria in cardiomyocytes. MicroRNAs (miRNAs) are single-stranded noncoding RNAs, approximately 22 nt in length, which play key roles in mediating post-transcriptional gene silencing. Numerous studies have confirmed that miRNAs can participate in the occurrence and development of cardiac diseases by regulating mitochondrial function-related genes and signaling pathways. Therefore, elucidating the crosstalk that occurs between miRNAs and mitochondria is important for the prevention and treatment of cardiac diseases. In this review, we discuss the biogenesis of miRNAs, the miRNA-mediated regulation of major genes involved in the maintenance of mitochondrial function, and the effects of miRNAs on mitochondrial function in cardiac diseases in order to provide a theoretical basis for the clinical prevention and treatment of cardiac disease and the development of new drugs.

Circulating microRNAs May Serve as Biomarkers for Hypertensive Emergency End-Organ Injuries and Address Underlying Pathways in an Animal Model

There is an incomplete understanding of the underlying pathophysiology in hypertensive emergencies, where severely elevated blood pressure causes acute end-organ injuries, as opposed to the long-term manifestations of chronic hypertension. Furthermore, current biomarkers are unable to detect early end-organ injuries like hypertensive encephalopathy and renal thrombotic microangiopathy. We hypothesized that circulating microRNAs (c-miRs) could identify acute and chronic complications of severe hypertension, and that combinations of c-miRs could elucidate important pathways involved. We studied the diagnostic accuracy of 145 c-miRs in Dahl salt-sensitive rats fed either a low-salt (N = 20: 0.3% NaCl) or a high-salt (N = 60: 8% NaCl) diet. Subclinical hypertensive encephalopathy and thrombotic microangiopathy were diagnosed by histopathology. In addition, heart failure with preserved ejection fraction was evaluated with echocardiography and N-terminal pro-brain natriuretic peptide; and endothelial dysfunction was studied using acetylcholine-induced aorta ring relaxation. Systolic blood pressure increased severely in animals on a high-salt diet (high-salt 205 ± 20 mm Hg vs. low-salt 152 ± 18 mm Hg, p < 0.001). Partial least squares discriminant analysis revealed 68 c-miRs discriminating between animals with and without hypertensive emergency complications. Twenty-nine c-miRs were strongly associated with hypertensive encephalopathy, 24 c-miRs with thrombotic microangiopathy, 30 c-miRs with heart failure with preserved ejection fraction, and 28 c-miRs with endothelial dysfunction. Hypertensive encephalopathy, thrombotic microangiopathy and heart failure with preserved ejection fraction were associated with deviations in many of the same c-miRs, whereas endothelial dysfunction was associated with a different set of c-miRs. Several of these c-miRs demonstrated fair to good diagnostic accuracy for a composite outcome of hypertensive encephalopathy, thrombotic microangiopathy and heart failure with preserved ejection fraction in receiver-operating-curve analyses (area-under-curve 0.75–0.88). Target prediction revealed an enrichment of genes related to several pathways relevant for cardiovascular disease (e.g., mucin type O-glycan biosynthesis, MAPK, Wnt, Hippo, and TGF-beta signaling). C-miRs could potentially serve as biomarkers of severe hypertensive end-organ injuries and elucidate important pathways involved.

Piperlongumine attenuates angiotensin-II-induced cardiac hypertrophy and fibrosis by inhibiting Akt-FoxO1 signalling

BACKGROUND

Cardiac hypertrophy and fibrosis are closely related to cardiac dysfunction, especially diastolic dysfunction. Limited medications can be used to simultaneously delay cardiac hypertrophy and fibrosis in clinical practice. Piperlongumine (PLG) is an amide alkaloid extracted from Piper longum and has been shown to have multiple biological effects, including anticancer and antioxidant effects. However, the role of PLG in cardiac hypertrophy and fibrosis is not clear.

PURPOSE

The aim of this study was to reveal the role of PLG in cardiac hypertrophy and fibrosis and the associated mechanism.

METHODS

Cardiac hypertrophy and fibrosis were induced by angiotensin II (Ang II) in vivo and in vitro. The effect of PLG in vivo, in vitro and its mechanism were investigated by proliferation and apoptosis assays, western blot, real-time PCR, immunofluorescence, histochemistry, echocardiography, flow cytometry and chromatin immunoprecipitation.

RESULTS

Proliferation and apoptosis assays showed that 2.5 μM PLG slightly inhibited proliferation and did not promote apoptosis. Treatment with 5 mg/kg PLG obviously inhibited Ang II-induced cardiac hypertrophy and fibrosis in vivo. In vitro studies of neonatal rat cardiomyocytes (NRCMs) showed that the anti-hypertrophic effect of PLG was mediated by reducing the phosphorylation of Akt and thereby preserving the level of Forkhead box transcription factor O1 (FoxO1), since knockdown of FoxO1 by siRNA reversed the protective effect of PLG on NRCMs. In addition, PLG significantly decreased the Ang II-induced expression of profibrotic proteins in neonatal cardiac fibroblasts by reducing the expression of Krüppel-like factor 4 (KLF4) and the recruitment of KLF4 to the promoter regions of transforming growth factor-β and connective tissue growth factor.

CONCLUSION

We demonstrate the cardioprotective effects of PLG in both cardiac hypertrophy and fibrosis and the potential value of PLG for developing novel medications for pathological cardiac hypertrophy and heart failure.

MiR-26a-5p inhibits GSK3β expression and promotes cardiac hypertrophy in vitro

Background

The role of miR-26a-5p expression in cardiac hypertrophy remains unclear. Herein, the effect of miR-26a-5p on cardiac hypertrophy was investigated using phenylephrine (PE)-induced cardiac hypertrophy in vitro and in a rat model of hypertension-induced hypertrophy in vivo.

Methods

The PE-induced cardiac hypertrophy models in vitro and vivo were established. To investigate the effect of miR-26a-5p activation on autophagy, the protein expression of autophagosome marker (LC3) and p62 was detected by western blot analysis. To explore the effect of miR-26a-5p activation on cardiac hypertrophy, the relative mRNA expression of cardiac hypertrophy related mark GSK3β was detected by qRT-PCR in vitro and vivo. In addition, immunofluorescence staining was used to detect cardiac hypertrophy related mark α-actinin. The cell surface area was measured by immunofluorescence staining. The direct target relationship between miR-26a-5p and GSK3β was confirmed by dual luciferase report.

Results

MiR-26a-5p was highly expressed in PE-induced cardiac hypertrophy. MiR-26a-5p promoted LC3II and decreased p62 expression in PE-induced cardiac hypertrophy in the presence or absence of lysosomal inhibitor. Furthermore, miR-26a-5p significantly inhibited GSK3β expression in vitro and in vivo. Dual luciferase report results confirmed that miR-26a-5p could directly target GSK3β. GSK3β overexpression significantly reversed the expression of cardiac hypertrophy-related markers including ANP, ACTA1 and MYH7. Immunofluorescence staining results demonstrated that miR-26a-5p promoted cardiac hypertrophy related protein α-actinin expression, and increased cell surface area in vitro and in vivo.

Conclusion

Our study revealed that miR-26a-5p promotes myocardial cell autophagy activation and cardiac hypertrophy by regulating GSK3β, which needs further research.

Inhibition of microRNA-146a attenuated heart failure in myocardial infarction rats

The aim of the present study was to determine the roles of microRNA (miR)-146a on myocardial infarction (MI)-induced heart failure and cardiac remodeling. Experiments were carried out in Sprague-Dawley rats treated with ligation of left coronary artery to induce heart failure, and in primary neonatal rat cardiac fibroblasts (CFs) and cardiomyocytes treated with angiotensin (Ang) II. Four weeks after MI, rats were injected with miR-146a antagomiR or agomiR via tail vein. After 2 weeks of injection, the rats were killed. In MI rats, left ventricle (LV) ejection fraction and fractional shortening were reduced, and LV volumes in diastole and systole were increased, which were reversed by miR-146a antagomiR, and further exacerbated after miR-146a agomiR treatment. Administration of miR-146a antagomiR improved the decreases of LV ±dp/dt_max and LV systolic pressure (LVSP), and the increase in LV end-diastolic pressure (LVEDP) of MI rats, but miR-146a agomiR deteriorated the LV ±dp/dt_max, LVSP and LVEDP. The increases in the levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), collagen I and collagen III in the heart, and ST2 and norepinephrine in the serum of MI rats were inhibited by miR-146a antagomiR, but aggravated after miR-146a agomiR treatment. The increases of collagen I and collagen III levels induced by Ang II in CFs, and the increases of ANP and BNP levels induced by Ang II in cardiomyocytes were inhibited by miR-146a antagomiR, but aggravated by miR-146a agomiR. These results demonstrated that inhibition of miR-146a improved cardiac dysfunction and cardiac remodeling in heart failure rats.

G6PD, bond by miR-24, regulates mitochondrial dysfunction and oxidative stress in phenylephrine-induced hypertrophic cardiomyocytes

AIMS

Pathological cardiac hypertrophy (CH) is one of the main risk factors for heart failure and cardiac death. Mitochondrial dysfunction and oxidative stress often occur in hypertrophic cardiomyocytes. It was recently proposed that deficiency or decreased activity of glucose-6-phosphate dehydrogenase (G6PD) may be related to the development of CH. This study aimed to investigate the expression of G6PD in CH and its regulatory role in mitochondrial dysfunction and oxidative stress of CH cells.

MAIN METHODS

Phenylephrine (PE) was used to create an in vitro model of CH. Using RT-qPCR and western blotting, the expression levels of target mRNAs and proteins were measured. ELISA assays and commercial kits based on spectrophotometry or colorimetry were used to measure mitochondrial function and oxidative stress. TargetScan and luciferase reporter gene assays were utilized for combination prediction and validation. CCK-8 and TUNEL kit were used to determine cell viability and apoptosis.

KEY FINDINGS

The results showed that G6PD overexpression attenuated the decreases of mitochondrial respiration, ATP, ATP synthetase and mitochondrial membrane potential induced by PE, as well as the increases of LDH release and apoptosis. Besides, PE elevated ROS activity, NO and MDA contents, and reduced SOD, CAT levels and cell viability. These effects were hindered by G6PD overexpression. MiR-24 was found to directly bind to G6PD at the motif of CUGAGCC and regulated its expression, furtherly, influenced the G6PD-mediated mitochondrial dysfunction and oxidative stress of CH cells.

SIGNIFICANCE

Generally, our study demonstrated that miR-24/G6PD regulates mitochondrial dysfunction and oxidative stress in CH cells, representing a new sight for CH therapy.

Downregulated expression of microRNAs associated with cardiac hypertrophy and fibrosis in physiological pregnancy and the association with echocardiographically-evaluated myocardial function

The aim of the present study was to analyze the profiles of cardiac microRNAs (miRNAs/miRs) in healthy pregnant women and non-pregnant controls. A total of 61 healthy women >18 years of age with singleton pregnancies in the third trimester were compared with 19 non-pregnant controls. Specifically, expression of miRNAs associated with cardiac hypertrophy (miR-1, miR-17-5, miR-22, miR-34a, miR-124, miR-133a, miR-195, miR-199a-3p, miR-199b, miR-210, miR-222 and miR-1249) and miRNAs associated with cardiac hypertrophy and fibrosis (miR-15b, miR-21, miR-26a, miR-29-a, miR-29c, miR-30c, miR-101, miR-146a, miR-191, miR-208a-5p and miR-328) were analyzed and compared with echocardiographic examination results. Both groups had similar cardiac miRNA expression profiles, but differed in quantitative evaluation. Women in the third trimester of physiological pregnancy exhibited downregulation of certain profibrotic miRNAs (miR-21, miR-30c and miR-328), decreased expression of a hypertrophic and antimetabolic miRNAs (miR-146a), downregulation of an antifibrotic miRNA (miR-222), and downregulation of a hypertrophic miRNA (miR-195). In pregnant women, the indices of systolic function were associated with miR-195 expression, and an interplay between miR-17-5p and diastolic function was observed. While the profiles of cardiac miRNAs expressed in healthy pregnant women and healthy non-pregnant controls were similar, these two groups differed in terms of expression of specific miRNAs. In the third trimester of physiological pregnancy, a downregulation of miR-17-5p, miR-21, miR-30c, miR-146a, miR-195, miR-222 and miR-328 was observed. The differences in the association between echocardiographic indices with miRNAs in pregnant and non-pregnant women suggest that miRNAs regulate both the structure and function of the pregnant heart, influencing cardiac muscle thickness as well as systolic and diastolic function.

Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart

In heart failure, a functional block of complex I of the respiratory chain provokes superoxide generation, which is transformed to H2O2 by dismutation. The Krebs cycle produces NADH, which delivers electrons to complex I, and NADPH for H2O2 elimination via isocitrate dehydrogenase and nicotinamide nucleotide transhydrogenase (NNT). At high NADH levels, α-ketoglutarate dehydrogenase (α-KGDH) is a major source of superoxide in skeletal muscle mitochondria with low NNT activity. Here, we analyzed how α-KGDH and NNT control H2O2 emission in cardiac mitochondria. In cardiac mitochondria from NNT-competent BL/6N mice, H2O2 emission is equally low with pyruvate/malate (P/M) or α-ketoglutarate (α-KG) as substrates. Complex I inhibition with rotenone increases H2O2 emission from P/M, but not α-KG respiring mitochondria, which is potentiated by depleting H2O2-eliminating capacity. Conversely, in NNT-deficient BL/6J mitochondria, H2O2 emission is higher with α-KG than with P/M as substrate, and further potentiated by complex I blockade. Prior depletion of H2O2-eliminating capacity increases H2O2 emission from P/M, but not α-KG respiring mitochondria. In cardiac myocytes, downregulation of α-KGDH activity impaired dynamic mitochondrial redox adaptation during workload transitions, without increasing H2O2 emission. In conclusion, NADH from α-KGDH selectively shuttles to NNT for NADPH formation rather than to complex I of the respiratory chain for ATP production. Therefore, α-KGDH plays a key role for H2O2 elimination, but is not a relevant source of superoxide in heart. In heart failure, α-KGDH/NNT-dependent NADPH formation ameliorates oxidative stress imposed by complex I blockade. Downregulation of α-KGDH may, therefore, predispose to oxidative stress in heart failure.

Correlation of miR-146a-5p plasma levels and rs2910164 polymorphism with left ventricle outflow tract obstruction in hypertrophic cardiomyopathy

OBJECTIVE

Hypertrophic cardiomyopathy (HCM) is a genetic disease of the myocardium that is characterized by phenotypic variability among patients. miR-146a is a small non-coding RNA that is well known for its role in inflammation and myocardial hypertrophy. The aim of this study is to evaluate the role of miR-146a as a candidate genetic factor influencing HCM phenotype.

METHODS

In this study, 140 HCM patients and 112 control individuals were genotyped for the rs2910164 single nucleotide polymorphism (SNP) in the MIR146A gene; using this data, the correlation between different genotypes and clinical features of the disease were determined. Additionally, plasma levels of miR-146a-5p were determined in 50 HCM patients and 30 control individuals by using qPCR.

RESULTS

The incidence of GC and CC genotypes were significantly lower in HCM patients (odds ratio (OR) = 0.5 [0.3-0.8], p = 0.007). The GC/CC genotypes in the dominant genetic model positively correlated with the presence of left ventricle outflow tract (LVOT) obstruction (OR = 2.3 [1.2-4.7] and p = 0.018), a higher left ventricle mass index (118 ± 47 g/m² vs 92 ± 42 g/m² and p = 0.02), and increased left ventricle end-diastolic diameter (4.66 ± 0.64cm vs 4.39 ± 0.7cm and p = 0.026). Atrial fibrillation was significantly higher in patients homozygous for the C allele (OR = 10.6 [2-55], p = 0.003). Interestingly, the plasma levels of miR-146a-5p were significantly increased in HCM patients with LVOT obstruction.

CONCLUSION

Our findings indicate that the C allele of the rs2910164 SNP might be under negative selection in HCM patients. Additionally, plasma levels of miR-146a-5p and GC/CC genotypes are indicative of the obstructive phenotype in HCM patients.

miR-26a-5p protects against myocardial ischemia/reperfusion injury by regulating the PTEN/PI3K/AKT signaling pathway

Reperfusion strategies in acute myocardial infarction (AMI) can cause a series of additional clinical damage, defined as myocardial ischemia/reperfusion (I/R) injury, and thus there is a need for effective therapeutic methods to attenuate I/R injury. miR-26a-5p has been proven to be an essential regulator for biological processes in different cell types. Nevertheless, the role of miR-26a-5p in myocardial I/R injury has not yet been reported. We established an I/R injury model in vitro and in vivo. In vitro, we used cardiomyocytes to simulate I/R injury using hypoxia/reoxygenation (H/R) assay. In vivo, we used C57BL/6 mice to construct I/R injury model. The infarct area was examined by TTC staining. The level of miR-26a-5p and PTEN was determined by bioinformatics methods, qRT-PCR, and western blot. In addition, the viability and apoptosis of cardiomyocytes were separately detected by MTT and flow cytometry. The targeting relationship between miR-26a-5p and PTEN was analyzed by the TargetScan website and luciferase reporter assay. I/R and H/R treatment induced myocardial tissue injury and cardiomyocyte apoptosis, respectively. The results showed that miR-26a-5p was down-regulated in myocardial I/R injury. PTEN was found to be a direct target of miR-26a-5p. Furthermore, miR-26a-5p effectively improved viability and inhibited apoptosis in cardiomyocytes upon I/R injury by inhibiting PTEN expression to activate the PI3K/AKT signaling pathway. miR-26a-5p could protect cardiomyocytes against I/R injury by regulating the PTEN/PI3K/AKT pathway, which offers a potential approach for myocardial I/R injury treatment.

NFATc3-dependent expression of miR-153-3p promotes mitochondrial fragmentation in cardiac hypertrophy by impairing mitofusin-1 expression

Mitochondrial dysfunction is involved in the pathogenesis of various cardiovascular disorders. Although mitochondrial dynamics, including changes in mitochondrial fission and fusion, have been implicated in the development of cardiac hypertrophy, the underlying molecular mechanisms remain mostly unknown. Here, we show that NFATc3, miR-153-3p, and mitofusion-1 (Mfn1) constitute a signaling axis that mediates mitochondrial fragmentation and cardiomyocyte hypertrophy.

Methods: Isoprenaline (ISO) was used to stimulate the hypertrophic response and mitochondrial fragmentation in cultured cardiomyocytes and in vivo. We performed immunoblotting, immunofluorescence, and quantitative real-time PCR to validate the function of Mfn1 in cardiomyocyte hypertrophy. Bioinformatic analyses, a luciferase reporter assay, and gain- and loss-of-function studies were used to demonstrate the biological function of miR-153-3p, which regulates mitochondrial fragmentation and hypertrophy by targeting Mfn1. Moreover, ChIP-qPCR and a luciferase reporter assay were performed to identify transcription factor NFATc3 as an upstream regulator to control the expression of miR-153-3p.

Results: Our results show that ISO promoted mitochondrial fission and enhanced the expression of miR-153-3p in cardiomyocytes. Knockdown of miR-153-3p attenuated ISO-induced mitochondrial fission and hypertrophy in cultured primary cardiomyocytes. miR-153-3p suppression inhibited mitochondrial fragmentation in ISO-induced cardiac hypertrophy in a mouse model. We identified direct targeting of Mfn1, a key protein of the mitochondrial fusion process, by miR-153-3p. Also, miR-153-3p promoted ISO-induced mitochondrial fission by suppressing the translation of Mfn1. We further found that NFATc3 activated miR-153-3p expression. Knockdown of NFATc3 inhibited miR-153-3p expression and blocked mitochondrial fission and hypertrophic response in cardiomyocytes.

Conclusions: Our data revealed a novel signaling pathway, involving NFATc3, miR-153-3p, and Mfn1, which could be a therapeutic target for the prevention and treatment of cardiac hypertrophy.

MicroRNA302-367-PI3K-PTEN-AKT-mTORC1 pathway promotes the development of cardiac hypertrophy through controlling autophagy

Cardiac hypertrophy at a decompensated state eventually leads to heart failure that mostly contributes to deaths globally. Dysregulated cardiac autophagy is a hallmark of a diseased heart, and a close contact between cardiac autophagy and cardiac hypertrophy is emerging. MicroRNAs (miRNAs) have been recently reported to be prominently implicated in cardiac hypertrophy through regulating cardiac autophagy. However, the role and function of miR302-367 clusters in cardiac autophagy and cardiac hypertrophy remain largely masked. Therefore, to investigate the performance of miR302-367 in cardiac hypertrophy, the specific in vitro hypertrophic model was established in H9c2 cells upon Ang II treatment. Consequently, we discovered a distinct inhibition on autophagy and a remarkable upregulation of miR302-367 expression in hypertrophic H9c2 cells. Besides, loss- and gain-of-function assays demonstrated miR302-367 inhibited autophagy and then aggravated cardiac hypertrophy. Mechanically, PTEN was predicted and confirmed as the shared target of miR302-367. Further, we recognized the apparent inactivation of PI3K/AKT/mTORC1 signaling in the face of miR302-367 suppression in Ang II-induced hypertrophic H9c2 cells. Moreover, co-treatment of PTEN inhibitor re-activated the PI3K/AKT/mTORC1 pathway, therefore counteracting the pro-autophagic and anti-hypertrophic effects of miR302-367 depletion on cardiomyocytes. These findings unveiled the pivotal role of the miR302-367 cluster in regulating cardiac autophagy and therefore modulating cardiac hypertrophy through PTEN/PI3K/AKT/mTORC1 signaling, indicating a promising therapeutic strategy for cardiac hypertrophy and even heart failure. Graphical abstract .

Mitochondrial MiRNA in Cardiovascular Function and Disease

MicroRNAs (miRNAs) are small noncoding RNAs functioning as crucial post-transcriptional regulators of gene expression involved in cardiovascular development and health. Recently, mitochondrial miRNAs (mitomiRs) have been shown to modulate the translational activity of the mitochondrial genome and regulating mitochondrial protein expression and function. Although mitochondria have been verified to be essential for the development and as a therapeutic target for cardiovascular diseases, we are just beginning to understand the roles of mitomiRs in the regulation of crucial biological processes, including energy metabolism, oxidative stress, inflammation, and apoptosis. In this review, we summarize recent findings regarding how mitomiRs impact on mitochondrial gene expression and mitochondrial function, which may help us better understand the contribution of mitomiRs to both the regulation of cardiovascular function under physiological conditions and the pathogenesis of cardiovascular diseases.

MicroRNA-Mediated Metabolic Reprograming in Renal Cancer

Metabolic reprogramming is one of the hallmarks of renal cell cancer (RCC). We hypothesized that altered metabolism of RCC cells results from dysregulation of microRNAs targeting metabolically relevant genes. Combined large-scale transcriptomic and metabolic analysis of RCC patients tissue samples revealed a group of microRNAs that contribute to metabolic reprogramming in RCC. miRNAs expressions correlated with their predicted target genes and with gas chromatography-mass spectrometry (GC-MS) metabolome profiles of RCC tumors. Assays performed in RCC-derived cell lines showed that miR-146a-5p and miR-155-5p targeted genes of PPP (the pentose phosphate pathway) (G6PD and TKT), the TCA (tricarboxylic acid cycle) cycle (SUCLG2), and arginine metabolism (GATM), respectively. miR-106b-5p and miR-122-5p regulated the NFAT5 osmoregulatory transcription factor. Altered expressions of G6PD, TKT, SUCLG2, GATM, miR-106b-5p, miR-155-5p, and miR-342-3p correlated with poor survival of RCC patients. miR-106b-5p, miR-146a-5p, and miR-342-3p stimulated proliferation of RCC cells. The analysis involving >6000 patients revealed that miR-34a-5p, miR-106b-5p, miR-146a-5p, and miR-155-5p are PanCancer metabomiRs possibly involved in global regulation of cancer metabolism. In conclusion, we found that microRNAs upregulated in renal cancer contribute to disturbed expression of key genes involved in the regulation of RCC metabolome. miR-146a-5p and miR-155-5p emerge as a key “metabomiRs” that target genes of crucial metabolic pathways (PPP (the pentose phosphate pathway), TCA cycle, and arginine metabolism).

miR-146a Suppresses SUMO1 Expression and Induces Cardiac Dysfunction in Maladaptive Hypertrophy

RATIONALE

Abnormal SUMOylation has emerged as a characteristic of heart failure (HF) pathology. Previously, we found reduced SUMO1 (small ubiquitin-like modifier 1) expression and SERCA2a (sarcoplasmic reticulum Ca²⁺-ATPase) SUMOylation in human and animal HF models. SUMO1 gene delivery or small molecule activation of SUMOylation restored SERCA2a SUMOylation and cardiac function in HF models. Despite the critical role of SUMO1 in HF, the regulatory mechanisms underlying SUMO1 expression are largely unknown.

OBJECTIVE

To examine miR-146a-mediated SUMO1 regulation and its consequent effects on cardiac morphology and function.

METHODS AND RESULTS

In this study, miR-146a was identified as a SUMO1-targeting microRNA in the heart. A strong correlation was observed between miR-146a and SUMO1 expression in failing mouse and human hearts. miR-146a was manipulated in cardiomyocytes through AAV9 (adeno-associated virus serotype 9)-mediated gene delivery, and cardiac morphology and function were analyzed by echocardiography and hemodynamics. Overexpression of miR-146a reduced SUMO1 expression, SERCA2a SUMOylation, and cardiac contractility in vitro and in vivo. The effects of miR-146a inhibition on HF pathophysiology were examined by transducing a tough decoy of miR-146a into mice subjected to transverse aortic constriction. miR-146a inhibition improved cardiac contractile function and normalized SUMO1 expression. The regulatory mechanisms of miR-146a upregulation were elucidated by examining the major miR-146a-producing cell types and transfer mechanisms. Notably, transdifferentiation of fibroblasts triggered miR-146a overexpression and secretion through extracellular vesicles, and the extracellular vesicle-associated miR-146a transfer was identified as the causative mechanism of miR-146a upregulation in failing cardiomyocytes. Finally, extracellular vesicles isolated from failing hearts were shown to contain high levels of miR-146a and exerted negative effects on the SUMO1/SERCA2a signaling axis and hence cardiomyocyte contractility.

CONCLUSIONS

Taken together, our results show that miR-146a is a novel regulator of the SUMOylation machinery in the heart, which can be targeted for therapeutic intervention.

Pathophysiological understanding of HFpEF: microRNAs as part of the puzzle

Half of all heart failure patients have preserved ejection fraction (HFpEF). Comorbidities associated with and contributing to HFpEF include obesity, diabetes and hypertension. Still, the underlying pathophysiological mechanisms of HFpEF are unknown. A preliminary consensus proposes that the multi-morbidity triggers a state of systemic, chronic low-grade inflammation, and microvascular dysfunction, causing reduced nitric oxide bioavailability to adjacent cardiomyocytes. As a result, the cardiomyocyte remodels its contractile elements and fails to relax properly, causing diastolic dysfunction, and eventually HFpEF. HFpEF is a complex syndrome for which currently no efficient therapies exist. This is notably due to the current one-size-fits-all therapy approach that ignores individual patient differences. MicroRNAs have been studied in relation to pathophysiological mechanisms and comorbidities underlying and contributing to HFpEF. As regulators of gene expression, microRNAs may contribute to the pathophysiology of HFpEF. In addition, secreted circulating microRNAs are potential biomarkers and as such, they could help stratify the HFpEF population and open new ways for individualized therapies. In this review, we provide an overview of the ever-expanding world of non-coding RNAs and their contribution to the molecular mechanisms underlying HFpEF. We propose prospects for microRNAs in stratifying the HFpEF population. MicroRNAs add a new level of complexity to the regulatory network controlling cardiac function and hence the understanding of gene regulation becomes a fundamental piece in solving the HFpEF puzzle.

Metabolic changes in hypertrophic cardiomyopathies: scientific update from the Working Group of Myocardial Function of the European Society of Cardiology

Disturbed metabolism as a consequence of obesity and diabetes may cause cardiac diseases (recently highlighted in the cardiovascular research spotlight issue on metabolic cardiomyopathies).¹ In turn, the metabolism of the heart may also be disturbed in genetic and acquired forms of hypertrophic cardiac disease. Herein, we provide an overview of recent insights on metabolic changes in genetic hypertrophic cardiomyopathy and discuss several therapies, which may be explored to target disturbed metabolism and prevent onset of cardiac hypertrophy.

This article is part of the Mini Review Series from the Varenna 2017 meeting of the Working Group of Myocardial Function of the European Society of Cardiology.

Non-coding RNAs in vascular disease - from basic science to clinical applications: scientific update from the Working Group of Myocardial Function of the European Society of Cardiology

Non-coding RNAs are increasingly recognized not only as regulators of various biological functions but also as targets for a new generation of RNA therapeutics and biomarkers. We hereby review recent insights relating to non-coding RNAs including microRNAs (e.g. miR-126, miR-146a), long non-coding RNAs (e.g. MIR503HG, GATA6-AS, SMILR), and circular RNAs (e.g. cZNF292) and their role in vascular diseases. This includes identification and therapeutic use of hypoxia-regulated non-coding RNAs and endogenous non-coding RNAs that regulate intrinsic smooth muscle cell signalling, age-related non-coding RNAs, and non-coding RNAs involved in the regulation of mitochondrial biology and metabolic control. Finally, we discuss non-coding RNA species with biomarker potential.This article is part of the Mini Review Series from the Varenna 2017 meeting of the Working Group of Myocardial Function of the European Society of Cardiology.

Non-coding RNAs: key players in cardiac disease

Molecular mechanisms underlying heart failure (HF) are only partly understood. Non-coding RNAs (ncRNAs) have been reported to control function and signalling routes in the myocardium. As ncRNAs such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs) or circular RNAs (circRNAs) can be selectively targeted via pharmacological approaches, this opens new avenues for diagnostic and therapeutic approaches. Here, we review the main ncRNA classes and how they influence cardiac biology. In addition we provide insight into the role of ncRNAs in chemotherapy-induced cardiac dysfunction. To provide a better understanding of ncRNAs in cardiovascular biology we present an outlook on specialized functions such as chromatin remodelling, biomarker potential and the recently discovered ncRNA-derived micropeptides.

Plasma MicroRNAs in Established Rheumatoid Arthritis Relate to Adiposity and Altered Plasma and Skeletal Muscle Cytokine and Metabolic Profiles

Background: MicroRNAs have been implicated in the pathogenesis of rheumatoid arthritis (RA), obesity, and altered metabolism. Although RA is associated with both obesity and altered metabolism, expression of RA-related microRNA in the setting of these cardiometabolic comorbidities is unclear. Our objective was to determine relationships between six RA-related microRNAs and RA disease activity, inflammation, body composition, and metabolic function. Methods: Expression of plasma miR-21, miR-23b, miR-27a, miR-143, miR-146a, and miR-223 was measured in 48 persons with seropositive and/or erosive RA (mean DAS-28-ESR 3.0, SD 1.4) and 23 age-, sex-, and BMI-matched healthy controls. Disease activity in RA was assessed by DAS-28-ESR. Plasma cytokine concentrations were determined by ELISA. Body composition was assessed using CT scan to determine central and muscle adipose and thigh muscle tissue size and tissue density. Plasma and skeletal muscle acylcarnitine, amino acid, and organic acid metabolites were measured via mass-spectroscopy. Plasma lipoproteins were measured via nuclear magnetic resonance (NMR) spectroscopy. Spearman correlations were used to assess relationships for microRNA with inflammation and cardiometabolic measures. RA and control associations were compared using Fisher transformations. Results: Among RA subjects, plasma miR-143 was associated with plasma IL-6 and IL-8. No other RA microRNA was positively associated with disease activity or inflammatory markers. In RA, microRNA expression was associated with adiposity, both visceral adiposity (miR-146a, miR-21, miR-23b, and miR-27a) and thigh intra-muscular adiposity (miR-146a and miR-223). RA miR-146a was associated with greater concentrations of cardiometabolic risk markers (plasma short-chain dicarboxyl/hydroxyl acylcarnitines, triglycerides, large VLDL particles, and small HDL particles) and lower concentrations of muscle energy substrates (long-chain acylcarnitines and pyruvate). Despite RA and controls having similar microRNA levels, RA, and controls differed in magnitude and direction for several associations with cytokines and plasma and skeletal muscle metabolic intermediates. Conclusion: Most microRNAs thought to be associated with RA disease activity and inflammation were more reflective of RA adiposity and impaired metabolism. These associations show that microRNAs in RA may serve as an epigenetic link between RA inflammation and cardiometabolic comorbidities.

Downregulation of microRNA‑199a‑5p attenuates hypoxia/reoxygenation‑induced cytotoxicity in cardiomyocytes by targeting the HIF‑1α‑GSK3β‑mPTP axis

MicroRNAs (miRs) have been identified as critical regulatory molecules in myocardial ischemia/reperfusion injury; however, the exact expression profile of miR-199a-5p in reperfusion injury and the underlying pathogenic mechanisms remain unclear. In the present study, it was revealed that miR-199a-5p expression was significantly increased in the plasma of patients with acute myocardial infarction and in a H9c2 cell model of oxygen-glucose deprivation and reperfusion (OGD/R) via reverse transcription-quantitative PCR. H9c2 cells were transfected with miR-199a-5p mimic or inhibitor, or short interfering RNA (siRNA) specific to hypoxia-inducible factor-1α (HIF-1α). MTS, lactate dehydrogenase (LDH), TUNEL staining and flow cytometry assays were performed to determine the proliferation, LDH activity, apoptosis and mitochondrial membrane potential (ΔΨm) of H9c2 cells, respectively. The overexpression of miR-199a-5p in the OGD/R cell model significantly decreased the viability and increased the lactate dehydrogenase leakage of cells; whereas knockdown of miR-199-5p induced the opposing effects. Additionally, inhibition of miR-199-5p significantly attenuated OGD/R-induced alterations to the mitochondrial transmembrane potential (ΔΨm) and increases in the apoptosis of cells. Furthermore, the overexpression or knockdown of miR-199a-5p decreased or increased the expression of HIF-1α and phosphorylation of glycogen synthase kinase 3β (GSK3β) in OGD/R-treated H9c2 cells. Additionally, siRNA-mediated downregulation of HIF-1α decreased phosphorylated (p)-GSK3β (Ser9) levels and reversed the protective effects of miR-199a-5p inhibition on OGD/R-injured H9c2 cells. Similarly, treatment with LiCl (a specific inhibitor of p-GSK3β) also attenuated the protective effects of miR-199a-5p knockdown on OGD/R-injured H9c2 cells. Mechanistic studies revealed that HIF-1α was a target of miR-199a-5p, and that HIF-1α downregulation suppressed the expression of p-GSK3β in OGD/R-injured H9c2 cells. Furthermore, an miR-199a-5p inhibitor increased the interaction between p-GSK3β and adenine nucleotide transferase (ANT), which was decreased by OGD/R. Additionally, miR-199a-5p inhibitor reduced the OGD/R-induced interaction between ANT and cyclophilin D (Cyp-D), potentially leading to the increased mitochondrial membrane potential in inhibitor-transfected OGD/R-injured H9c2 cells. Collectively, the present study identified a novel regulatory pathway in which the upregulation of miR-199a-5p reduced the expression of HIF-1α and p-GSK3β, and potentially suppresses the interaction between p-GSK3β and ANT, thus promoting the interaction between ANT and Cyp-D and potentially inducing cytotoxicity in OGD/R-injured H9c2 cells.

The TIR/BB-loop mimetic AS-1 prevents Ang II-induced hypertensive cardiac hypertrophy via NF-κB dependent downregulation of miRNA-143

Untreated pathological cardiac hypertrophy, which can be caused by sustained systemic hypertension, may lead to heart failure. In the present study, we investigated whether AS-1 had attenuating effects on hypertension-induced cardiac hypertrophy, and whether this process was mediated by the regulation of miRNA-143. To induce the hypertrophic response in vitro, cardiomyocytes were stimulated with Ang II for 24hs. AS-1 administration strongly attenuated Ang II-induced hypertrophic response of cardiomyocytes. Chronical infusion of Ang II via implanted osmotic mini-pump induced increased blood pressure and cardiac hypertrophy in vivo. AS-1 administration attenuated hypertension-induced cardiac hypertrophy by, at least in part, inhibin of MAPK signaling. We observed, for the first time, upregulated expression of miRNA-143 in Ang II-induced cardiomyocytes, and inhibition of miRNA-143 significantly reduced the Ang II-induced hypertrophic responses. Importantly, AS-1 administration diminished the Ang II-induced upregulation of miRNA-143. Overexpression of miRNA-143 abolished the attenuating effects of AS-1 on Ang II-induced hypertrophic response of cardiomyocytes. Additionally, AS-1 administration abrogates Ang II-induced nuclear translocation of p50 NF-κB subunit in hypertrophic cardiomyocytes. Application of NF-κB inhibitor significantly suppressed Ang II-induced upregulation of miRNA-143. Our data suggest a novel mechanism by which AS-1 attenuates Ang II-induced hypertrophic response through downregulation miRNA-143 expression in a NF-κB-dependent manner.

microRNA-146a-5p association with the cardiometabolic disease risk factor TMAO

Trimethylamine-N-oxide (TMAO), a microbial choline metabolism byproduct that is processed in the liver and excreted into circulation, is associated with increased atherosclerotic lesion formation and cardiovascular disease risk. Genetic regulators of TMAO levels are largely unknown. In the present study, we used 288 mice from a genetically heterogeneous mouse population [Diversity Outbred (DO)] to determine hepatic microRNA associations with TMAO in the context of an atherogenic diet. We also validated findings in two additional animal models of atherosclerosis: liver-specific insulin receptor knockout mice fed a chow diet (LIRKO) and African green monkeys fed high-fat/high-cholesterol diet. Small RNA-sequencing analysis in DO mice, LIRKO mice, and African green monkeys identified only one hepatic microRNA (miR-146a-5p) that is aberrantly expressed across all three models. Moreover, miR-146a-5p levels are associated with circulating TMAO after atherogenic diet in each of these models. We also performed high-resolution genetic mapping and identified a novel quantitative trait locus on Chromosome 12 for TMAO levels. This interval includes two genes, Numb and Dlst, which are inversely correlated with both miR-146a and TMAO and are predicted targets of miR-146a. Both of these genes have been validated as direct targets of miR-146a, though in other cellular contexts. This is the first report to our knowledge of a link between miR-146 and TMAO. Our findings suggest that miR-146-5p, as well as one or more genes at the Chromosome 12 QTL (possibly Numb or Dlst), is strongly linked to TMAO levels and likely involved in the control of atherosclerosis.

Cardiac Hypertrophy is Positively Regulated by MicroRNA‑24 in Rats

Background:

MicroRNA-24 (miR-24) plays an important role in heart failure by reducing the efficiency of myocardial excitation-contraction coupling. Prolonged cardiac hypertrophy may lead to heart failure, but little is known about the role of miR-24 in cardiac hypertrophy. This study aimed to preliminarily investigate the function of miR-24 and its mechanisms in cardiac hypertrophy.

Methods:

Twelve Sprague-Dawley rats with a body weight of 50 ± 5 g were recruited and randomly divided into two groups: a transverse aortic constriction (TAC) group and a sham surgery group. Hypertrophy index was measured and calculated by echocardiography and hematoxylin and eosin staining. TargetScans algorithm-based prediction was used to search for the targets of miR-24, which was subsequently confirmed by a real-time polymerase chain reaction and luciferase assay. Immunofluorescence labeling was used to measure the cell surface area, and ³H-leucine incorporation was used to detect the synthesis of total protein in neonatal rat cardiac myocytes (NRCMs) with the overexpression of miR-24. In addition, flow cytometry was performed to observe the alteration in the cell cycle. Statistical analysis was carried out with GraphPad Prism v5.0 and SPSS 19.0. A two-sided P < 0.05 was considered as the threshold for significance.

Results:

The expression of miR-24 was abnormally increased in TAC rat cardiac tissue (t = −2.938, P < 0.05). TargetScans algorithm-based prediction demonstrated that CDKN1B (p27, Kip1), a cell cycle regulator, was a putative target of miR-24, and was confirmed by luciferase assay. The expression of p27 was decreased in TAC rat cardiac tissue (t = 2.896, P < 0.05). The overexpression of miR-24 in NRCMs led to the decreased expression of p27 (t = 4.400, P < 0.01), and decreased G0/G1 arrest in cell cycle and cardiomyocyte hypertrophy.

Conclusion:

MiR-24 promotes cardiac hypertrophy partly by affecting the cell cycle through down-regulation of p27 expression.

Construction of a microRNA‑associated feed‑forward loop network that identifies regulators of cardiac hypertrophy and acute myocardial infarction

Feed‑forward loops (FFLs) are three‑gene modules that exert significant effects on a series of biological processes and carcinogenesis development. MicroRNA‑associated FFLs (miR‑FFLs) represent a new era in disease research. However, analysis of the miR‑FFL network motifs has yet to be systematically performed, and their potential role in cardiac hypertrophy and acute myocardial infarction (AMI) requires investigation. The present study used a computational method to establish a comprehensive miR‑FFL network for cardiac hypertrophy and AMI, by integrating high‑throughput data from different sources and performing multi‑aspect analysis of the network features. Several heart disease‑associated miR‑FFL motifs were identified that were specific or common to the two diseases investigated. Functional analysis further revealed that miR‑FFL motifs provided specific drug targets for the clinical treatment of cardiac hypertrophy and AMI. Associations between specific drugs associated with heart disease and dysregulated FFLs were also identified. The present study highlighted the components of FFL motifs in cardiac hypertrophy and AMI, and revealed their possibility as heart disease biomarkers and novel treatment targets.