MicroRNA regulation of autophagy in cardiovascular disease

Molecular Morbidity Score-Can MicroRNAs Assess the Burden of Disease?

Multimorbidity refers to the presence of two or more chronic diseases and is associated with adverse outcomes for patients. Factors such as an ageing population have contributed to a rise in prevalence of multimorbidity globally; however, multimorbidity is often neglected in clinical guidelines. This is largely because patients with multimorbidity are systematically excluded from clinical trials. Accordingly, there is an urgent need to develop novel biomarkers and methods of prognostication for this cohort of patients. The hallmarks of ageing are now thought to potentiate the pathogenesis of multimorbidity. MicroRNAs are small, regulatory, noncoding RNAs which have been implicated in the pathogenesis and prognostication of numerous chronic diseases; there is a substantial body of evidence now implicating microRNA dysregulation with the different hallmarks of ageing in the aetiology of chronic diseases. This article proposes using the hallmarks of ageing as a framework to develop a panel of microRNAs to assess the prognostic burden of multimorbidity. This putative molecular morbidity score would have many potential applications, including assessing the efficacy of clinical interventions, informing clinical decision making and facilitating wider inclusion of patients with multimorbidity in clinical trials.

Modulation of atherosclerosis-related signaling pathways by Chinese herbal extracts: Recent evidence and perspectives

Atherosclerotic cardiovascular disease remains a preeminent cause of morbidity and mortality globally. The onset of atherosclerosis underpins the emergence of ischemic cardiovascular diseases, including coronary heart disease (CHD). Its pathogenesis entails multiple factors such as inflammation, oxidative stress, apoptosis, vascular endothelial damage, foam cell formation, and platelet activation. Furthermore, it triggers the activation of diverse signaling pathways including Phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt), NF-E2-related factor 2/antioxidant response element (Nrf2/ARE), the Notch signaling pathway, peroxisome proliferator-activated receptor (PPAR), nucleotide oligo-structural domain-like receptor thermoprotein structural domain-associated protein 3 (NLRP3), silencing information regulator 2-associated enzyme 1 (Sirt1), nuclear transcription factor-κB (NF-κB), Circular RNA (Circ RNA), MicroRNA (mi RNA), Transforming growth factor-β (TGF-β), and Janus kinase-signal transducer and activator of transcription (JAK/STAT). Over recent decades, therapeutic approaches for atherosclerosis have been dominated by the utilization of high-intensity statins to reduce lipid levels, despite significant adverse effects. Consequently, there is a growing interest in the development of safer and more efficacious drugs and therapeutic modalities. Traditional Chinese medicine (TCM) offers a vital strategy for the prevention and treatment of cardiovascular diseases. Numerous studies have detailed the mechanisms through which TCM active ingredients modulate signaling molecules and influence the atherosclerotic process. This article reviews the signaling pathways implicated in the pathogenesis of atherosclerosis and the advancements in research on TCM extracts for prevention and treatment, drawing on original articles from various databases including Google Scholar, Medline, CNKI, Scopus, and Pubmed. The objective is to furnish a reference for the clinical management of cardiovascular diseases.

Research progress of autophagy in heart failure

Heart failure poses a significant threat to global public health within the realm of cardiovascular diseases. Its pathological progression involves various alterations in cardiomyocytes, among which autophagy, a crucial intracellular degradation mechanism, plays a pivotal role. Autophagy facilitates the breakdown of damaged organelles and proteins, thereby maintaining cellular homeostasis. In the context of heart failure, autophagy coexists with apoptosis and necrosis, influencing myocardial hypertrophy and ventricular remodeling. However, its impact on heart failure manifests a dual nature: moderate autophagy aids in cardiac repair, whereas excessive autophagy may exacerbate ventricular remodeling and cell demise. This review delves into the fundamental biology of autophagy, elucidating its involvement in the pathological cascade of heart failure and its correlation with cardiac hypertrophy and ventricular remodeling. Furthermore, an analysis of the interplay between autophagy regulatory factors and heart failure sheds light on the potential therapeutic implications of autophagy in the prevention and management of heart failure. This exploration provides a theoretical foundation for novel treatment strategies in combating heart failure.

Noncoding RNAs as therapeutic targets in autophagy-related diabetic cardiomyopathy

Diabetic cardiomyopathy, a multifaceted complication of diabetes mellitus, remains a major challenge in clinical management due to its intricate pathophysiology. Emerging evidence underscores the pivotal role of autophagy dysregulation in the progression of diabetic cardiomyopathy, providing a novel avenue for therapeutic intervention. Noncoding RNAs (ncRNAs), a diverse class of regulatory molecules, have recently emerged as promising candidates for targeted therapeutic strategies. The exploration of various classes of ncRNAs, including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs) reveal their intricate regulatory networks in modulating autophagy and influencing the pathophysiological processes associated with diabetic cardiomyopathy. The nuanced understanding of the molecular mechanisms underlying ncRNA-mediated autophagic regulation offers a rationale for the development of precise and effective therapeutic interventions. Harnessing the regulatory potential of ncRNAs presents a promising frontier for the development of targeted and personalized therapeutic strategies, aiming to ameliorate the burden of diabetic cardiomyopathy in affected individuals. As research in this field advances, the identification and validation of specific ncRNA targets hold immense potential for the translation of these findings into clinically viable interventions, ultimately improving outcomes for patients with diabetic cardiomyopathy. This review encapsulates the current understanding of the intricate interplay between autophagy and diabetic cardiomyopathy, with a focus on the potential of ncRNAs as therapeutic targets.

Early Growth Response-1: Friend or Foe in the Heart?

Cardiovascular disease is a major cause of mortality and morbidity worldwide. Early growth response-1 (Egr-1) plays a critical regulatory role in a range of experimental models of cardiovascular diseases. Egr-1 is an immediate-early gene and is upregulated by various stimuli including shear stress, oxygen deprivation, oxidative stress and nutrient deprivation. However, recent research suggests a new, underexplored cardioprotective side of Egr-1. The main purpose of this review is to explore and summarise the dual nature of Egr-1 in cardiovascular pathobiology.

MiR18a5p aggravates homocysteineinduced myocardial injury via autophagy

OBJECTIVES

Hyperhomocysteinaemia (Hcy) is an independent risk factor for cardiovascular and cerebrovascular diseases. MicroRNA (miR)-18a-5p is closely related to cardiovascular diseases. This study aims to investigate the effects of miR-18a-5p on homocysteine (Hcy)-induced myocardial cells injury.

METHODS

H9c2 cells were transfected with miR-18a-5p mimic/miR-18a-5p mimic negative control (NC) or combined with Hcy for intervention, and untreated cells were set as a control group. The transfection efficiency was verified by real-time RT-PCR, and cell counting kit-8 (CCK-8) assay was used to determine cell viability. Flow cytometry was used to detect apoptosis and reactive oxygen species (ROS) levels. Western blotting was performed to measure the protein levels of microtubule-associated protein 1 light chain 3 (LC3)-I, LC3-II, Beclin1, p62, Bax, Bcl-2, and Notch2. Dual luciferase reporter assay was used to detect the interaction of miR-18a-5p with Notch2.

RESULTS

Compared with the control, treatment with Hcy or transfection with miR-18a-5p mimic alone, or combined treatment with Hcy and miR-18a-5p mimic/miR-18a-5p mimic NC significantly reduced the H9c2 cell viability, promoted apoptosis and ROS production, up-regulated the expressions of Bax and Beclin, down-regulated the expressions of Bcl-2, p62, and Notch2, and increased the ratio of LC3-II/LC3-I (all P<0.05). Compared with the combined intervention of miR-18a-5p mimic NC and Hcy group, the above indexes were more significantly changed in the combined intervention of miR-18a-5p mimic and Hcy group, and the difference between the 2 groups was statistically significant (all P<0.05). There is a targeted binding between Notch2 and miR-18a-5p.

CONCLUSIONS

MiR-18a-5p could induce autophagy and apoptosis via increasing ROS production in cardiomyocytes, and aggravate Hcy-induced myocardial injury. Notch2 is a target of miR-18a-5p.

Research progress on the relationship between autophagy and chronic complications of diabetes

Diabetes is a common metabolic disease whose hyperglycemic state can induce diverse complications and even threaten human health and life security. Currently, the treatment of diabetes is restricted to drugs that regulate blood glucose and have certain accompanying side effects. Autophagy, a research hotspot, has been proven to be involved in the occurrence and progression of the chronic complications of diabetes. Autophagy, as an essential organismal defense mechanism, refers to the wrapping of cytoplasmic proteins, broken organelles or pathogens by vesicles, which are then degraded by lysosomes to maintain the stability of the intracellular environment. Here, we review the relevant aspects of autophagy and the molecular mechanisms of autophagy in diabetic chronic complications, and further analyze the impact of improving autophagy on diabetic chronic complications, which will contribute to a new direction for further prevention and treatment of diabetic chronic complications.

MicroRNA-590-3p relieves hypoxia/reoxygenation induced cardiomyocytes apoptosis and autophagy by targeting HIF-1α

Autophagy and apoptosis are key factors in myocardial ischemia/reperfusion (I/R) injury. MicroRNAs (miRNAs or miRs) participate in occurrence and development of myocardial I/R injury by regulating autophagy and apoptosis. The purpose of the present study was to investigate the role of miR-590-3p in the regulation of autophagy and apoptosis in hypoxia/reoxygenation (H/R)-treated cardiomyocytes. Following 6 h hypoxia and 6 h reoxygenation in primary rat cardiomyocytes, miR-590-3p was downregulated. Transfection of miR-590-3p mimic inhibited the increased autophagy and apoptosis following H/R treatment. Subsequent experiments demonstrated that miR-590-3p regulated induction of autophagy and apoptosis by targeting hypoxia inducible factor (HIF)-1α. Forced expression of HIF-1α rescued the protective effect of miR-590-3p on H/R-induced cardiomyocytes. In summary, the present study showed that miR-590-3p exhibited a protective effect on H/R-induced cardiomyocyte injury and may be a novel target for the treatment of myocardial ischemia disease.

Crucial Roles of microRNA-Mediated Autophagy in Urologic Malignancies

Urologic oncologies are major public health problems worldwide. Both microRNA and autophagy, separately or concurrently, are involved in a variety of the cellular and molecular processes of multiple cancers, including urologic malignancies. In this review, we have summarized the related studies and found that microRNA-mediated autophagy acted as carcinogenic factors or suppressors in prostate cancer, kidney cancer, and bladder cancer. MiRNAs, targeted genes, and the different signaling pathways constitute a complex network that orchestrates autophagy regulation, militating the oncogenic and tumor-suppressive effects in urologic malignancies. Aberrant expression of miRNAs may induce the dysregulation of the autophagy process, resulting in tumorigenesis, progression, and resistance to anticancer therapies. Targeting specific miRNAs for autophagy modulation may present as reliable diagnostic and prognostic biomarkers or promising therapeutic strategies for urologic oncologies.

The Dawn of Mitophagy: What Do We Know by Now?

Mitochondria are essential organelles for healthy eukaryotic cells. They produce energyrich phosphate bond molecules (ATP) through oxidative phosphorylation using ionic gradients. The presence of mitophagy pathways in healthy cells enhances cell protection during mitochondrial damage. The PTEN-induced putative kinase 1 (PINK1)/Parkin-dependent pathway is the most studied for mitophage. In addition, there are other mechanisms leading to mitophagy (FKBP8, NIX, BNIP3, FUNDC1, BCL2L13). Each of these provides tethering of a mitochondrion to an autophagy apparatus via the interaction between receptor proteins (Optineurin, p62, NDP52, NBR1) or the proteins of the outer mitochondrial membrane with ATG9-like proteins (LC3A, LC3B, GABARAP, GABARAPL1, GATE16). Another pathogenesis of mitochondrial damage is mitochondrial depolarization. Reactive oxygen species (ROS) antioxidant responsive elements (AREs) along with antioxidant genes, including pro-autophagic genes, are all involved in mitochondrial depolarization. On the other hand, mammalian Target of Rapamycin Complex 1 (mTORC1) and AMP-dependent kinase (AMPK) are the major regulatory factors modulating mitophagy at the post-translational level. Protein-protein interactions are involved in controlling other mitophagy processes. The objective of the present review is to analyze research findings regarding the main pathways of mitophagy induction, recruitment of the autophagy machinery, and their regulations at the levels of transcription, post-translational modification and protein-protein interaction that appeared to be the main target during the development and maturation of neurodegenerative disorders.

miR-30e-3p Promotes Cardiomyocyte Autophagy and Inhibits Apoptosis via Regulating Egr-1 during Ischemia/Hypoxia

Background

Microvascular obstruction (MVO) can result in coronary microcirculation embolism and myocardial microinfarction. Myocardial injury induced by MVO is characterized by continuous ischemia and hypoxia of cardiomyocytes. Autophagy and apoptosis are closely associated with various cardiovascular diseases. Based on our previous study, we observed a decrease in miR-30e-3p expression and an increase in Egr-1 expression in a rat coronary microembolization model. However, the specific function of miR-30e-3p in regulating autophagy and apoptosis in an ischemia/hypoxia (IH) environment remains to be deciphered. We exposed cardiomyocytes to an IH environment and then determined whether miR-30e-3p was involved in promoting cardiomyocyte autophagy and inhibiting apoptosis by regulating Egr-1.

Methods

Cardiomyocytes were isolated from rats for our in vitro study. miR-30e-3p was either overexpressed or inhibited by transfection with lentiviral vectors into cardiomyocytes. 3-Methyladenine (3-MA) was used to inhibit autophagy. RT-qPCR and western blotting were used to determine the expression levels of miR-30e-3p, Egr-1, and proteins related to the autophagy and apoptosis process. Autophagic vacuoles and autophagic flux were evaluated using transmission electron microscopy (TEM) and confocal microscopy, respectively. Cardiomyocyte viability was evaluated using the MTS assay. Cell injury was assessed by lactate dehydrogenase (LDH) leakage, and apoptosis was determined by flow cytometry.

Results

Both miR-30e-3p expression and autophagy were significantly inhibited, and apoptosis was increased in cardiomyocytes after 9 hours of IH exposure. Overexpression of miR-30e-3p increased autophagy and inhibited apoptosis, as well as suppressed Egr-1 expression and decreased cell injury. In addition, inhibition of miR-30e-3p reduced autophagy and increased apoptosis and cell injury.

Conclusions

miR-30e-3p may be involved in promoting cardiomyocyte autophagy and inhibiting apoptosis by indirectly regulating Egr-1 expression in an IH environment.

LncRNA 0003250 accelerates heart autophagy and binds to miR-17-5p as a competitive endogenous RNA in chicken induced by selenium deficiency

Long noncoding RNAs (LncRNAs) have been demonstrated to be associated with a variety of myocardial diseases, but how LncRNAs regulate autophagy in selenium (Se)-deficient myocardial injury is infrequently reported. Here, we screened out a novel long noncoding RNA, microRNA, and ATG7 through transcriptomic results. We employed a Se-deficient chicken model in vivo, and primary cultured cardiomyocytes treated by correlation in vitro. The results showed that Se deficiency upregulated the expression of ATG7, and miR-17-5p inhibited cardiomyocyte autophagy by targeting ATG7. Furthermore, we found that LncRNA 0003250 regulated miR-17-5p, and thus affected the expression of ATG7 and autophagic cell death. Our present study proposed a novel model for the regulation of cardiomyocytes autophagy, which includes LncRNA 0003250, miR-17-5p and ATG7 in the chicken heart. Our conclusions may provide a feasible diagnostic tool for Se-deficient cardiomyocyte injury.

Autophagy regulation by microRNAs: Novel insights into osteosarcoma therapy

Osteosarcoma (OS) is a kind of primary bone cancer that is considered as the leading cause of children death. Surgery and chemotherapy are considered as common treatment approaches for OS; the rate of survival for patients is almost 60-70%. Besides the used therapeutic approaches, it seems that there is a crucial need to launch new treatments for OS. In this regard, more understanding about cellular and molecular pathways involved in OS can contribute to recovery and develop new therapeutic platforms. Autophagy is a cellular machinery that digests and degrades dysfunctional proteins and organelles, so it can regulate the cell proliferation and survival. Most of the time, OS cells use autophagy to increase their survival and proliferation and to gain the ability to resist chemotherapy. Although, there are several controversial evidences on how OS cells use autophagy. A variety of cellular and molecular pathways, that is, microRNAs (miRNAs) can modulate autophagy. MiRNAs are some endogenous, approximately 22 nucleotide RNAs that have an important role in posttranscriptional regulation of mRNAs by targeting them. There are many evidences that the various miRNA expressions in OS cells are dysregulated, so it can propel a normal cell to cancerous one by influencing the cell survival, apoptosis, and autophagy, and eventually increased chemoresitance. Hence, miRNAs can be considered as new biomarkers for OS diagnosis, and according to the role of autophagy in OS progression, miRNAs can use inhibiting or promoting autophagy agents. The present review summarizes the effects of aberrant expression of miRNAs in OS diagnosis and treatment with focus on their roles in autophagy.

MicroRNAs play an essential role in autophagy regulation in various disease phenotypes

Autophagy is a highly conserved catabolic process and fundamental biological process in eukaryotic cells. It recycles intracellular components to provide nutrients during starvation and maintains quality control of organelles and proteins. In addition, autophagy is a well-organized homeostatic cellular process that is responsible for the removal of damaged organelles and intracellular pathogens. Moreover, it also modulates the innate and adaptive immune systems. Micro ribonucleic acids (microRNAs) are a mature class of post-transcriptional modulators that are widely expressed in tissues and organs. And, it can suppress gene expression by targeting messenger RNAs for translational repression or, at a lesser extent, degradation. Research indicates that microRNAs regulate autophagy through different pathways, playing an essential role in the treatment of various diseases. It is an important regulator of fundamental cellular processes such as proliferation, autophagy, and cell apoptosis. In this review article, we first review the current knowledge of autophagy and the function of microRNAs. Then, we summarize the mechanism of autophagy and the signaling pathways related to autophagy by citing at least the main proteins involved in the different phases of the process. Second, we introduce other members of RNA and report some examples in various pathologies. Finally, we review the current literature regarding microRNA-based therapies for cancer, atherosclerosis, cardiac disease, tuberculosis, and viral diseases. MicroRNAs can cause autophagy upregulation or downregulation by targeting genes or affecting autophagy-related signaling pathways. Therefore, the microRNAs have a huge potential in autophagy regulation, and it is the function as diagnostic and prognostic markers.

Elevated pulmonary tuberculosis biomarker miR-423-5p plays critical role in the occurrence of active TB by inhibiting autophagosome-lysosome fusion

Rapid diagnosis of pulmonary tuberculosis is an effective measure to prevent the spread of tuberculosis. However, the grim fact is that the new, rapid, and safe methods for clinical diagnosis are lacking. Moreover, although auto-lysosome is critical in clearing Mycobacterium tuberculosis, the pathological significance of microRNAs, as biomarkers of tuberculosis, in autophagosome maturation is unclear. Here, these microRNAs were investigated by Solexa sequencing and qPCR validation, and a potential diagnostic model was established by logistic regression. Besides that, the mechanism of one of the microRNAs involved in the occurrence of tuberculosis was studied. The results showed that the expression of miR-423-5p, miR-17-5p, and miR-20b-5p were significantly increased in the serum of patients with tuberculosis. The combination of these three microRNAs established a model to diagnose tuberculosis with an accuracy of 78.18%, and an area under the curve value of 0.908. Bioinformatics analysis unveiled miR-423-5p as the most likely candidate in regulating autophagosome maturation. The up-regulation of miR-423-5p could inhibit autophagosome maturation through suppressing autophagosome–lysosome fusion in macrophages. Further investigations showed that VPS33A was the direct target of miR-423-5p, and the two CUGCCCCUC domains in VPS33A 3’-UTR were the direct regulatory sites for miR-423-5p. In addition, an inverse correlation between VPS33A and miR-423-5p was found in peripheral blood mononuclear cells of patients with tuberculosis. Since the inhibition of autolysosome formation plays a critical role in tuberculosis occurrence, our findings suggests that miR-423-5p could suppress autophagosome–lysosome fusion by post-transcriptional regulation of VPS33A, which might be important for the occurrence of active tuberculosis.

miR-27a-5p Attenuates Hypoxia-induced Rat Cardiomyocyte Injury by Inhibiting Atg7

Acute myocardial infarction (AMI) is an ischemic heart disease with high mortality worldwide. AMI triggers a hypoxic microenvironment and induces extensive myocardial injury, including autophagy and apoptosis. MiRNAs, which are a class of posttranscriptional regulators, have been shown to be involved in the development of ischemic heart diseases. We have previously reported that hypoxia significantly alters the miRNA transcriptome in rat cardiomyoblast cells (H9c2), including miR-27a-5p. In the present study, we further investigated the potential function of miR-27a-5p in the cardiomyocyte response to hypoxia, and showed that miR-27a-5p expression was downregulated in the H9c2 cells at different hypoxia-exposed timepoints and the myocardium of a rat AMI model. Follow-up experiments revealed that miR-27a-5p attenuated hypoxia-induced cardiomyocyte injury by regulating autophagy and apoptosis via Atg7, which partly elucidated the anti-hypoxic injury effects of miR-27a-5p. Taken together, this study shows that miR-27a-5p has a cardioprotective effect on hypoxia-induced H9c2 cell injury, suggesting it may be a novel target for the treatment of hypoxia-related heart diseases.

MicroRNAs as Potential Pharmaco-targets in Ischemia-Reperfusion Injury Compounded by Diabetes

BACKGROUND

Ischemia-Reperfusion (I/R) injury is the tissue damage that results from re-oxygenation of ischemic tissues. There are many players that contribute to I/R injury. One of these factors is the family of microRNAs (miRNAs), which are currently being heavily studied. This review aims to critically summarize the latest papers that attributed roles of certain miRNAs in I/R injury, particularly in diabetic conditions and dissect their potential as novel pharmacologic targets in the treatment and management of diabetes.

METHODS

PubMed was searched for publications containing microRNA and I/R, in the absence or presence of diabetes. All papers that provided sufficient evidence linking miRNA with I/R, especially in the context of diabetes, were selected. Several miRNAs are found to be either pro-apoptotic, as in the case of miR-34a, miR-144, miR-155, and miR-200, or anti-apoptotic, as in the case of miR-210, miR-21, and miR-146a. Here, we further dissect the evidence that shows diverse cell-context dependent effects of these miRNAs, particularly in cardiomyocytes, endothelial, or leukocytes. We also provide insight into cases where the possibility of having two miRNAs working together to intensify a given response is noted.

CONCLUSIONS

This review arrives at the conclusion that the utilization of miRNAs as translational agents or pharmaco-targets in treating I/R injury in diabetic patients is promising and becoming increasingly clearer.

Synchronized Orchestration of miR-99b and let-7g Positively Regulates Rotavirus Infection by Modulating Autophagy

Rotavirus (RV), the major etiological agent of viral gastroenteritis in young children, kills over 200 thousand infants each year. In spite of available vaccines, rotaviral diarrhoea is still a major problem in developing countries of Asia and Africa. Therefore, the studies on RV infection and host antiviral responses are warranted. The active correlation between virus infection and activation of autophagy machinery and positive influence of autophagy on RV replication have been documented recently. Previous study from our group showed dysregulation of several cellular miRNAs during RV infection, though their significance remained largely unknown. Since cellular microRNAs (miRNAs) have been implicated in the control of several fundamental biological processes including stress response and autophagy, we focused on two miRNAs, miR-99b and let-7g, and analyzed their function to gain insight into the miRNA-autophagy crosstalk during RV infection. This study shows that RV suppresses let-7g expression but enhances miR-99b that in turn augment major autophagy regulators. Ectopic expression of let-7g and knockdown of miR-99b resulted in inhibition of autophagy, hence, reduction of RV replication. Overall, our study highlights new mechanistic insights for understanding the role of miRNAs in modulating RV infection and possibility of using RNA interference as an antiviral therapeutic target.

Silencing H19 regulated proliferation, invasion, and autophagy in the placenta by targeting miR-18a-5p

Fetal growth restriction (FGR) is a serious pregnancy complication associated with increased perinatal mortality and morbidity. It may lead to neurodevelopmental impairment and adulthood onset disorders. Recently, long noncoding RNAs (lncRNAs) were found to be associated with the pathogenesis of FGR. Here we report that the lncRNAH19 is significantly decreased in placentae from pregnancies with FGR. Downregulation of H19 leads to reduced proliferation and invasion of extravillous trophoblast cells. This is identified with reduced trophoblast invasion, which has been discovered in FGR. Autophagy is exaggerated in FGR. Downregulation of H19 promotes autophagy via the PI3K/AKT/mTOR and MAPK/ERK/mTOR pathways of extravillous trophoblast cells in FGR. We also found that the expression level of microRNAs miR-18a-5p was negatively correlated with that of H19. H19 can act as an endogenous sponge by directly binding to miR-18a-5p, which targets IRF2. The expression of miR-18a-5p was upregulated, but IRF2 expression was downregulated after the H19 knockdown. In conclusion, our study revealed that H19 downexpressed could inhibit proliferation and invasion, and promote autophagy by targeting miR-18a-5pin HTR8 and JEG3 cells. We propose that aberrant regulation of H19/miR-18a-5p-mediated regulatory pathway may contribute to the molecular mechanism of FGR. We indicated that H19 may be a potential predictive, diagnostic, and therapeutic modality for FGR.

Emerging Role of mTOR Signaling-Related miRNAs in Cardiovascular Diseases

Mechanistic/mammalian target of rapamycin (mTOR), an atypical serine/threonine kinase of the phosphoinositide 3-kinase- (PI3K-) related kinase family, elicits a vital role in diverse cellular processes, including cellular growth, proliferation, survival, protein synthesis, autophagy, and metabolism. In the cardiovascular system, the mTOR signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of both physiological and pathological processes. MicroRNAs (miRs), a class of short noncoding RNA, are an emerging intricate posttranscriptional modulator of critical gene expression for the development and maintenance of homeostasis across a wide array of tissues, including the cardiovascular system. Over the last decade, numerous studies have revealed an interplay between miRNAs and the mTOR signaling circuit in the different cardiovascular pathophysiology, like myocardial infarction, hypertrophy, fibrosis, heart failure, arrhythmia, inflammation, and atherosclerosis. In this review, we provide a comprehensive state of the current knowledge regarding the mechanisms of interactions between the mTOR signaling pathway and miRs. We have also highlighted the latest advances on mTOR-targeted therapy in clinical trials and the new perspective therapeutic strategies with mTOR-targeting miRs in cardiovascular diseases.

A MicroRNA Perspective on Cardiovascular Development and Diseases: An Update

In this review, we summarize the latest research pertaining to MicroRNAs (miRs) related to cardiovascular diseases. In today's molecular age, the key clinical aspects of diagnosing and treating these type of diseases are crucial, and miRs play an important role. Therefore, we have made a thorough analysis discussing the most important candidate protagonists of many pathways relating to such conditions as atherosclerosis, heart failure, myocardial infarction, and congenital heart disorders. We approach miRs initially from the fundamental molecular aspects and look at their role in developmental pathways, as well as regulatory mechanisms dysregulated under specific cardiovascular conditions. By doing so, we can better understand their functional roles. Next, we look at therapeutic aspects, including delivery and inhibition techniques. We conclude that a personal approach for treatment is paramount, and so understanding miRs is strategic for cardiovascular health.

MicroRNA-21 suppresses ox-LDL-induced human aortic endothelial cells injuries in atherosclerosis through enhancement of autophagic flux: Involvement in promotion of lysosomal function

Atherosclerosis is a common pathological basis of cardiovascular disease and remains the leading cause of mortality. Endothelial cell (EC) injury and autophagy dysfunction have been proved to contribute to the development of atherosclerosis. Recently, accumulating evidence confirms that microRNAs (miRNAs) have emerged as vital regulators and fine-tuners of various pathophysiological cellular impacts and molecular signaling pathways involved in atherosclerosis. Herein, the objective of the present study was to explore the biological function of miR-21 in oxidized low-density lipoprotein (ox-LDL)-induced human aortic endothelial cells (HAECs) injury and the underlying molecular mechanism. The results showed that ox-LDL treatment significantly decreased HAECs viability, increased caspase-3 activity, apoptosis ratio and Bax protein expression, and reduced Bcl-2 protein expression resulting in EC injuries. Simultaneously, ox-LDL treatment obviously reduced miR-21 level in a time-and dose-dependent manner. Notably, ox-LDL-induced EC injuries were abolished by miR-21 mimics transfection. In addition, miR-21 mimics alleviated ox-LDL-induced impaired autophagic flux as illustrated by the increases in LC3-II/LC3-I ratio and Beclin-1 protein expression, and the decrease in p62 protein expression in HAECs. Moreover, ox-LDL suppressed the expressions of lysosomal membrane protein (LAMP1) and cathepsin D proteins, and attenuated cathepsin D activity in HAECs, leading to lysosomal dysfunction, while these effects were also blocked by miR-21 mimics. These findings indicated that miR-21 restored impaired autophagic flux and lysosomal dysfunction, thereby attenuating ox-LDL-induced HAECs injuries.

Effect of Wenxin Granules on Gap Junction and MiR-1 in Rats with Myocardial Infarction

Myocardial infarction (MI) patients are at high risk of potential lethal arrhythmia. Gap junction and microRNA-1 (miR-1) are both arrhythmia generating conditions. The present study investigated whether Wenxin Granules (Wenxin-Keli, WXKL) could prevent potential lethal arrhythmia by improving gap junctions and miR-1 following MI. Male Sprague-Dawley rats were divided randomly into control, model, metoprolol, low dose WXKL, and high dose WXKL groups. The MI rat model was created by coronary artery ligation. Treatments were administrated intragastrically to the rats for 4 weeks. Conventional transmission electron microscopy was performed to observe the ultrastructure of gap junctions. Quantitative real-time PCR and western blotting were used to detect the expression of miR-1, protein kinase C (PKC), and related proteins. Additionally, a programmatic electrophysiological stimulation test was performed to detect the ventricular fibrillation threshold (VFT). WXKL protected the ultrastructure of the gap junctions and their constituent Cx43 by regulating miR-1 and PKC mediated signal transduction and increased the VFT significantly in the rat MI model. The results suggested that WXKL is an effective alternative medicine to prevent potentially lethal arrhythmia following MI.

miRNA Expression Profile and Effect of Wenxin Granule in Rats with Ligation-Induced Myocardial Infarction

Wenxin Granule (WXKL) is a traditional Chinese medicine used for treatment of myocardial infarction (MI) and arrhythmias. However, the genomic pathological mechanisms of MI and mechanisms of WXKL are largely unknown. This study aims to investigate a comprehensive miRNA expression profile, and the predicted correlation pathways to be targeted by differentially expressed miRNAs in MI, and mechanisms of WXKL from a gene level. MI rat model was established by a coronary artery ligation surgery. miRNA expression microarrays were performed and the data were deposited in Gene Expression Omnibus (GEO number GSE95855). And, pathway analysis was performed by using the DIANA-miRPath v3.0 online tool. The expressions of miR-1, miR-133, Cx43, and Cx45 were detected by quantitative real-time PCR. It was found that 35 differentially expressed miRNAs and 23 predicted pathways, including miR-1, miR-133, and gap junction pathway, are involved in the pathogenesis of MI. And, WXKL increased the expressions of miR-1 and miR-133, while also increased the mRNA levels of Cx43 and Cx45, and, especially, recovered the Cx43/Cx45 ratio near to normal level. The results suggest that regulatory effects on miR-1, miR-133, Cx43, and Cx45 might be a possible mechanism of WXKL in the treatment of MI at the gene level.

MicroRNA-18a-5p functions as an oncogene by directly targeting IRF2 in lung cancer

Lung cancer is the major form of cancer resulting in cancer-related mortality around the world. MicroRNAs are endogenous small non-coding single-stranded RNAs, which can engage in the regulation of gene expression. In this study, miR-18a-5p significantly upregulated in non-small cell lung cancer (NSCLC) tissues and NSCLC cell lines, suggesting an oncogenic function in lung cancer. Additionally, miR-18a-5p can promote carcinogenesis by directly targeting interferon regulatory factor 2 (IRF2). Further experiments indicated that IRF2 can increase cell apoptosis, inhibit cell proliferation and migration ability. Our study demonstrates that miR-18a-5p promotes autophagy in NSCLC. Collectively, these results indicate that miR-18a-5p can not only promote NSCLC by suppressing IRF2, but also will be a promising target in the near future.