MicroRNA-146a as a Regulator of Cardiac Energy Metabolism

Valerenic acid attenuates pathological myocardial hypertrophy by promoting the utilization of multiple substrates in the mitochondrial energy metabolism

INTRODUCTION

Valerenic acid (VA) is a unique and biologically active component in Valeriana officinalis L., which has been reported to have a regulatory effect on the cardiovascular system. However, its therapeutic effects on pathological myocardial hypertrophy (PMH) and the underlying mechanisms are undefined.

OBJECTIVES

Our study aims to elucidate how VA improves PMH, and preliminarily discuss its mechanism.

METHODS

The efficacy of VA on PMH was confirmed by in vivo and in vitro experiments and the underlying mechanism was investigated by molecular dynamics (MD) simulations and specific siRNA interference.

RESULTS

VA enhanced cardiomyocyte fatty acid oxidation (FAO), inhibited hyper-activated glycolysis, and improved the unbalanced pyruvate-lactate axis. VA could significantly improve impaired mitochondrial function and reduce the triglyceride (TG) in the hypertrophic myocardium while reducing the lactate (LD) content. Molecular mechanistic studies showed that VA up-regulated the expression of peroxisome proliferator-activated receptor-α (PPARα) and downstream FAO-related genes including CD36, CPT1A, EHHADH, and MCAD. VA reduced the expression of ENO1 and PDK4, the key enzymes in glycolysis. Meanwhile, VA improved the pyruvate-lactate axis and promoted the aerobic oxidation of pyruvate by inhibiting LDAH and MCT4. MD simulations confirmed that VA can bind with the F273 site of PPARα, which proposes VA as a potential activator of the PPARα.

CONCLUSION

Our results demonstrated that VA might be a potent activator for the PPARα-mediated pathway. VA directly targets the PPARα and subsequently promotes energy metabolism to attenuate PMH, which can be applied as a potentially effective drug for the treatment of HF.

Overview of Panax ginseng and its active ingredients protective mechanism on cardiovascular diseases

ETHNIC PHARMACOLOGICAL RELEVANCE

Panax ginseng is a traditional Chinese herbal medicine used to treat cardiovascular diseases (CVDs), and it is still widely used to improve the clinical symptoms of various CVDs. However, there is currently a lack of summary and analysis on the mechanism of Panax ginseng exerts its cardiovascular protective effects. This article provides a review of in vivo and in vitro pharmacological studies on Panax ginseng and its active ingredients in reducing CVDs damage.

AIM OF THIS REVIEW

This review summarized the latest literature on Panax ginseng and its active ingredients in CVDs research, aiming to have a comprehensive and in-depth understanding of the cardiovascular protection mechanism of Panax ginseng, and to provide new ideas for the treatment of CVDs, as well as to optimize the clinical application of Panax ginseng.

METHODS

Enrichment of pathways and biological terms using the traditional Chinese medicine molecular mechanism bioinformatics analysis tool (BATMAN-TCM). The literature search is based on electronic databases such as PubMed, ScienceDirect, Scopus, CNKI, with a search period of 2002-2023. The search terms include Panax ginseng, Panax ginseng ingredients, ginsenosides, ginseng polysaccharides, ginseng glycoproteins, ginseng volatile oil, CVDs, heart, and cardiac.

RESULTS

132 articles were ultimately included in the review. The ingredients in Panax ginseng that manifested cardiovascular protective effects are mainly ginsenosides (especially ginsenoside Rb1). Ginsenosides protected against CVDs such as ischemic reperfusion injury, atherosclerosis and heart failure mainly through improving energy metabolism, inhibiting hyper-autophagy, antioxidant, anti-inflammatory and promoting secretion of exosomes.

CONCLUSION

Panax ginseng and its active ingredients have a particularly prominent effect on improving myocardial energy metabolism remodeling in protecting against CVDs. The AMPK and PPAR signaling pathways are the key targets through which Panax ginseng produces multiple mechanisms of cardiovascular protection. Extracellular vesicles and nanoparticles as carriers are potential delivery ways for optimizing the bioavailability of Panax ginseng and its active ingredients.

miR-20a-5p regulated SMAD6 to inhibit chondrogenesis of hDPSCs

OBJECTIVES

Chondrogenic differentiation of human dental pulp stem cells (hDPSCs) is highly promising for cartilage repair. The specific mechanism, however, still needs to be explicated.

MATERIALS AND METHODS

In this study, we isolated hDPSCs and transfected cells with lentiviruses containing an over-expression, knock-down, or negative control of miR-20a-5p. Three-D pellet cultures of hDPSCs were used for the chondrogenic induction. Following the pellet culture period, chondrogenesis was assessed by histological and immunohistochemical analysis and expression of chondrogenic-related genes. Dual-luciferase report assay was performed to determine potential targeted genes of miR-20a-5p, and the phosphorylation levels of P65 and IκBα were explored. Animal experiments were performed to determine the effect of miR-20a-5p on cartilage regeneration.

RESULTS

miR-20a-5p was showed to repress the expression of SMAD6 to inhibit the chondrogenic differentiation of hDPSCs. Accordingly, the knock-down of miR-20a-5p promoted cartilage regeneration in the osteochondral defects of rats. Mechanically, it is indicated that NF-κB signaling is the potential down-stream network of miR-20a-5p/Smad6 crosstalk during chondrogenic differentiation.

CONCLUSIONS

miR-20a-5p could target SMAD6 to activate NF-κB signaling pathway, and thus inhibit chondrogenesis of hDPSCs, which provided promising therapeutic target for cartilage defects clinically.

Cardiac Metabolism and MiRNA Interference

The aberrant increase in cardio-metabolic diseases over the past couple of decades has drawn researchers' attention to explore and unveil the novel mechanisms implicated in cardiometabolic diseases. Recent evidence disclosed that the derangement of cardiac energy substrate metabolism plays a predominant role in the development and progression of chronic cardiometabolic diseases. Hence, in-depth comprehension of the novel molecular mechanisms behind impaired cardiac metabolism-mediated diseases is crucial to expand treatment strategies. The complex and dynamic pathways of cardiac metabolism are systematically controlled by the novel executor, microRNAs (miRNAs). miRNAs regulate target gene expression by either mRNA degradation or translational repression through base pairing between miRNA and the target transcript, precisely at the 3' seed sequence and conserved heptametrical sequence in the 5' end, respectively. Multiple miRNAs are involved throughout every cardiac energy substrate metabolism and play a differential role based on the variety of target transcripts. Novel theoretical strategies have even entered the clinical phase for treating cardiometabolic diseases, but experimental evidence remains inadequate. In this review, we identify the potent miRNAs, their direct target transcripts, and discuss the remodeling of cardiac metabolism to cast light on further clinical studies and further the expansion of novel therapeutic strategies. This review is categorized into four sections which encompass (i) a review of the fundamental mechanism of cardiac metabolism, (ii) a divulgence of the regulatory role of specific miRNAs on cardiac metabolic pathways, (iii) an understanding of the association between miRNA and impaired cardiac metabolism, and (iv) summary of available miRNA targeting therapeutic approaches.

A novel therapeutic strategy for alleviating atrial remodeling by targeting exosomal miRNAs in atrial fibrillation

Atrial fibrillation (AF) is one of the most frequent cardiac arrhythmias, and atrial remodeling is related to the progression of AF. Although several therapeutic approaches have been presented in recent years, the continuously increasing mortality rate suggests that more advanced strategies for treatment are urgently needed. Exosomes regulate pathological processes through intercellular communication mediated by microribonucleic acid (miRNA) in various cardiovascular diseases (CVDs). Exosomal miRNAs associated with signaling pathways have added more complexity to an already complex direct cell-to-cell interaction. Exosome delivery of miRNAs is involved in cardiac regeneration and cardiac protection. Recent studies have found that exosomes play a critical role in the diagnosis and treatment of cardiac fibrosis. By improving exosome stability and modifying surface epitopes, specific pharmaceutical agents can be supplied to improve tropism and targeting to cells and tissues in vivo. Exosomes harboring miRNAs may have clinical utility in cell-free therapeutic approaches and may serve as prognostic and diagnostic biomarkers for AF. Currently, limitations challenge pharmaceutic design, therapeutic utility and in vivo targeted delivery to patients. The aim of this article is to review the developmental features of AF associated with exosomal miRNAs and relate them to underlying mechanisms.

MicroRNA-146a-5p alleviates lipopolysaccharide-induced NLRP3 inflammasome injury and pro-inflammatory cytokine production via the regulation of TRAF6 and IRAK1 in human umbilical vein endothelial cells (HUVECs)

Background

Microribonucleic acids (miRNAs) have an evident role in regulating endothelial inflammation and dysfunction, which characterizes the early stages of atherosclerosis. The NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome has been reported to contribute to the endothelial inflammatory response that promotes atherosclerosis development and progression. This study sought to investigate the effects of miR-146a-5p on lipopolysaccharide (LPS)-induced NLRP3 inflammasome injury and pro-inflammatory cytokine production in human umbilical vein endothelial cells (HUVECs).

Methods

HUVECs were transfected with a miR-146a-5p mimic, small-interfering RNA (siRNA) (si-TRAF6, and si-IRAK1), and were then stimulated with LPS for 24 h. The messenger (mRNA) and the protein levels of p-NF-κB/NF-κB, NLRP3, Caspase-1, pro-inflammatory cytokine [interleukin (IL)-6, IL-1β and tumor necrosis factor alpha (TNF-α)] in the HUVECs were analyzed by quantitative real-time polymerase chain reactions (PCRs) and western blot assays, respectively. The secretion of IL-6 from the cells was detected by enzyme-linked immunoassay (ELISA). Bioinformatic and dual-luciferase reporter assays were performed to identify the targets of miR-146a-5p.

Results

LPS promoted pro-inflammatory cytokine expression in a dose-dependent manner and significantly increased the expression levels of p-NF-κB/NF-κB p65, NLRP3, and Caspase-1. After transfection with a miR-146a-5p mimic, or si-TRAF6 or si-IRAK1, we observed that the mRNA and protein levels of NF-κB/p-NF-κB, NLRP3, Caspase-1, and pro-inflammatory cytokine in the HUVECs were all down-regulated, and the secretion of IL-6 from cells declined significantly. After transfection with a miR-146-5p mimic, the expression of TRAF6 and IRAK1 in HUVECs were both down-regulated. Dual-luciferase reporter assays confirmed that miR-146-5p directly targets the 3'-untranslated region (3'-UTR) of TRAF6 and IRAK1 to regulate their expression.

Conclusions

As a modulator of TRAF6 and IRAK1, miR-146a-5p negatively regulated LPS-induced NF-κB activation and the NLRP3 inflammasome signaling pathway in HUVECs. Thus, miRNA-146a-5p may serve as a potential therapeutic target for atherosclerosis.

Regulation of Mitochondrial Function by Noncoding RNAs in Heart Failure and Its Application in Diagnosis and Treatment

ABSTRACT

Heart failure (HF) is the terminal stage of multiple cardiovascular diseases. However, the pathogenesis of HF remains unclear and prompt; appropriate diagnosis and treatment of HF are crucial. Cardiomyocytes isolated from HF subjects frequently present mitochondrial impairment and dysfunction. Many studies have suggested that the regulation by noncoding RNAs (ncRNAs) of mitochondria can affect the occurrence and progression of HF. The regulation by ncRNAs of myocardial mitochondria during HF and the recent applications of ncRNAs in the diagnosis and treatment of HF are summarized in this review that is intended to gain keen insights into the mechanisms of HF and more effective treatments.

miRNAs may play a major role in the control of gene expression in key pathobiological processes in Chagas disease cardiomyopathy

Chronic Chagas disease cardiomyopathy (CCC), an especially aggressive inflammatory dilated cardiomyopathy caused by lifelong infection with the protozoan Trypanosoma cruzi, is a major cause of cardiomyopathy in Latin America. Although chronic myocarditis may play a major pathogenetic role, little is known about the molecular mechanisms responsible for its severity. The aim of this study is to study the genes and microRNAs expression in tissues and their connections in regards to the pathobiological processes. To do so, we integrated for the first time global microRNA and mRNA expression profiling from myocardial tissue of CCC patients employing pathways and network analyses. We observed an enrichment in biological processes and pathways associated with the immune response and metabolism. IFNγ, TNF and NFkB were the top upstream regulators. The intersections between differentially expressed microRNAs and differentially expressed target mRNAs showed an enrichment in biological processes such as Inflammation, inflammation, Th1/IFN-γ-inducible genes, fibrosis, hypertrophy, and mitochondrial/oxidative stress/antioxidant response. MicroRNAs also played a role in the regulation of gene expression involved in the key cardiomyopathy-related processes fibrosis, hypertrophy, myocarditis and arrhythmia. Significantly, a discrete number of differentially expressed microRNAs targeted a high number of differentially expressed mRNAs (>20) in multiple processes. Our results suggest that miRNAs orchestrate expression of multiple genes in the major pathophysiological processes in CCC heart tissue. This may have a bearing on pathogenesis, biomarkers and therapy.

Chronic Chagas disease cardiomyopathy (CCC), an aggressive dilated cardiomyopathy caused by Trypanosoma cruzi, is a major cause of cardiomyopathy in Latin America. Little is known about the molecular mechanisms responsible for its severity. Authors study the possible role of microRNAs in the regulation of gene expression in relevant pathways and pathobiological processes. Differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) -small RNAs that can regulate gene expression—associated to severe cardiomyopathy development. The inflammatory mediator Interferon-γ was the most likely inducer of gene expression in CCC, and most genes belonged to the immune response, fibrosis, hypertrophy and mitochondrial metabolism. A discrete number of differentially expressed mRNAs targeted a high number of differentially expressed mRNAs in multiple processes. Moreover, several pathways had multiple targets regulated by microRNAs, suggesting synergic effect. Results suggest that microRNAs orchestrate expression of multiple genes in the major pathophysiological processes in CCC heart tissue.

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.

RNAase III-Type Enzyme Dicer Regulates Mitochondrial Fatty Acid Oxidative Metabolism in Cardiac Mesenchymal Stem Cells

Cardiac mesenchymal stem cells (C-MSC) play a key role in maintaining normal cardiac function under physiological and pathological conditions. Glycolysis and mitochondrial oxidative phosphorylation predominately account for energy production in C-MSC. Dicer, a ribonuclease III endoribonuclease, plays a critical role in the control of microRNA maturation in C-MSC, but its role in regulating C-MSC energy metabolism is largely unknown. In this study, we found that Dicer knockout led to concurrent increase in both cell proliferation and apoptosis in C-MSC compared to Dicer floxed C-MSC. We analyzed mitochondrial oxidative phosphorylation by quantifying cellular oxygen consumption rate (OCR), and glycolysis by quantifying the extracellular acidification rate (ECAR), in C-MSC with/without Dicer gene deletion. Dicer gene deletion significantly reduced mitochondrial oxidative phosphorylation while increasing glycolysis in C-MSC. Additionally, Dicer gene deletion selectively reduced the expression of β-oxidation genes without affecting the expression of genes involved in the tricarboxylic acid (TCA) cycle or electron transport chain (ETC). Finally, Dicer gene deletion reduced the copy number of mitochondrially encoded 1,4-Dihydronicotinamide adenine dinucleotide (NADH): ubiquinone oxidoreductase core subunit 6 (MT-ND6), a mitochondrial-encoded gene, in C-MSC. In conclusion, Dicer gene deletion induced a metabolic shift from oxidative metabolism to aerobic glycolysis in C-MSC, suggesting that Dicer functions as a metabolic switch in C-MSC, which in turn may regulate proliferation and environmental adaptation.

MicroRNA-124 regulates cardiomyocyte apoptosis and myocardial infarction through targeting Dhcr24

AIMS

microRNA-124(miR-124) has recently been reported to be elevated in cardiovascular disease. In this study, we aimed to investigate the exact role of miR-124 in cardiomyocytes and myocardial infarction, identifying the functional target and its regulatory mechanisms.

METHODS AND RESULTS

Cultured cardiomyocytes, myocardial-infarction mouse model, and clinical data were used to study the effects of miR-124 on myocardial ischemia. Expression of miR-124 was up-regulated in H₂O₂ and hypoxia induced cardiomyocyte injury. miR-124 over-expression significantly increased cardiomyocyte apoptosis, whereas miR-124 inhibition attenuated cell death. 3β-hydroxysteroid-Delta24 reductase (Dhcr24), a multi-functional enzyme implicated in cholesterol synthesis and various diseases, was identified as a novel functional target of miR-124 in cardiac myocytes. The miR-124-Dhcr24 axis was responsible for cardiomyocyte apoptosis regulation. Furthermore, myocardial infarction induced miR-124 activation and Dhcr24 reduction in vivo. Modulation of miR-124 by intra-myocardial injection of agomiR or antagomiR was capable of manipulating cardiomyocyte apoptosis and myocardial infarction in mice. More importantly, circulating miR-124 was also observed to be elevated in acute myocardial infarction (AMI) patients and was correlated with myocardial injury and cardiac function.

CONCLUSION

Our findings strongly demonstrated that miR-124 targeting Dhcr24 regulates oxidative stress and hypoxia induced cardiomyocyte apoptosis and myocardial infarction. The miR-124-Dhcr24 axis could be a potential biomarker as well as the therapeutic target for AMI.

Cardiovascular Risk Factors and Markers

Cardiovascular risk is assessed for the prediction and appropriate management of patients using collections of identified risk markers obtained from clinical questionnaire information, concentrations of certain blood molecules (e.g., N-terminal proB-type natriuretic peptide fragment and soluble receptors of tumor-necrosis factor-α and interleukin-2), imaging data using various modalities, and electrocardiographic variables, in addition to traditional risk factors.