MicroRNA-365 accelerates cardiac hypertrophy by inhibiting autophagy via the modulation of Skp2 expression

Synthetic Non-Coding RNA for Suppressing mTOR Translation to Prevent Renal Fibrosis Related to Autophagy in UUO Mouse Model

The global burden of chronic kidney disease is increasing, and the majority of these diseases are progressive. Special site-targeted drugs are emerging as alternatives to traditional drugs. Oligonucleotides (ODNs) have been proposed as effective therapeutic tools in specific molecular target therapies for several diseases. We designed ring-type non-coding RNAs (ncRNAs), also called mTOR ODNs to suppress mammalian target rapamycin (mTOR) translation. mTOR signaling is associated with excessive cell proliferation and fibrogenesis. In this study, we examined the effects of mTOR suppression on chronic renal injury. To explore the regulation of fibrosis and inflammation in unilateral ureteral obstruction (UUO)-induced injury, we injected synthesized ODNs via the tail vein of mice. The expression of inflammatory-related markers (interleukin-1β, tumor necrosis factor-α), and that of fibrosis (α-smooth muscle actin, fibronectin), was decreased by synthetic ODNs. Additionally, ODN administration inhibited the expression of autophagy-related markers, microtubule-associated protein light chain 3, Beclin1, and autophagy-related gene 5-12. We confirmed that ring-type ODNs inhibited fibrosis, inflammation, and autophagy in a UUO mouse model. These results suggest that mTOR may be involved in the regulation of autophagy and fibrosis and that regulating mTOR signaling may be a therapeutic strategy against chronic renal injury.

Cardioprotective Effect of Paeonol on Chronic Heart Failure Induced by Doxorubicin via Regulating the miR-21-5p/S-Phase Kinase-Associated Protein 2 Axis

Background

This study primarily explored the role of paeonol in doxorubicin (DOX)-induced chronic heart failure (CHF), considering the cardioprotective effect of paeonol on an epirubicin-induced cardiac injury.

Methods

DOX-induced CHF-modeled rats were treated with paeonol. Cardiac function and myocardial damage in rats were evaluated by using the multifunction instrument, and the histopathology, apoptosis, and the expression of miR-21-5p and S-phase kinase-associated protein 2 (SKP2) in myocardium were detected. The target gene of miR-21-5p was confirmed by a dual-luciferase reporter assay. After the required transfection or paeonol treatment, the viability, apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) of the DOX-induced cardiomyocytes were determined. Reverse-transcription quantitative-PCR (RT-qPCR) and Western blot were performed to quantify the expressions of miR-21-5p, SKP2, and apoptosis-related factors.

Results

Paeonol improved cardiac function and also ameliorated the cardiac damage of CHF-modeled rats, where the downregulation of abnormally elevated myocardial damage markers, including brain natriuretic peptide, lactate dehydrogenase, renin, angiotensin II, aldosterone, and endothelin 1, was observed. Paeonol alleviated the histopathological injury and suppressed the apoptosis in CHF-modeled rats, inhibited miR-21-5p expression, and upregulated SKP2 expression in vitro and in vivo. miR-21-5p targeted SKP2. Paeonol and SKP2 increased the viability and MMP, but reduced apoptosis and ROS in the DOX-induced cardiomyocytes. miR-21-5p exerted effects opposite to PAE and SKP2, and it downregulated the expression of Bcl-2 and mitochondrion-Cytochrome c (Cyt c) and upregulated the expression of Bax, C-caspase-3, and cytoplasm-Cyt c. miR-21-5p reversed the effects of paeonol, and its effects were further reversed by SKP2.

Conclusion

Paeonol shows a cardioprotective effect on DOX-induced CHF via regulating the miR-21-5p/SKP2 axis.

MicroRNA-365a/b-3p as a Potential Biomarker for Hypertrophic Scars

The clinical aspects of hypertrophic scarring vary according to personal constitution and body part. However, the mechanism of hypertrophic scar (HS) formation remains unclear. MicroRNAs (miRNAs) are known to contribute to HS formation, however, their detailed role remains unknown. In this study, candidate miRNAs were identified and analyzed as biomarkers of hypertrophic scarring for future clinical applications. HSfibroblasts and normal skin fibroblasts from patients were used for profiling and validation of miRNAs. An HS mouse model with xenografted human skin on nude mice was established. The miRNA expression between normal human, normal mouse, and mouse HS skin tissues was compared. Circulating miRNA expression levels in the serum of normal mice and mice with HSs were also analyzed. Ten upregulated and twenty-one downregulated miRNAs were detected. Among these, miR-365a/b-3p and miR-16-5p were identified as candidate miRNAs with statistically significant differences; miR-365a/b-3p was significantly upregulated (p = 0.0244). In mouse studies, miR-365a/b-3p expression levels in skin tissue and serum were higher in mice with HSs than in the control group. These results indicate that miRNAs contribute to hypertrophic scarring and that miR-365a/b-3p may be considered a potential biomarker for HS formation.

MicroRNA-34c-5p provokes isoprenaline-induced cardiac hypertrophy by modulating autophagy via targeting ATG4B

Pathological cardiac hypertrophy serves as a significant foundation for cardiac dysfunction and heart failure. Recently, growing evidence has revealed that microRNAs (miRNAs) play multiple roles in biological processes and participate in cardiovascular diseases. In the present research, we investigate the impact of miRNA-34c-5p on cardiac hypertrophy and the mechanism involved. The expression of miR-34c-5p was proved to be elevated in heart tissues from isoprenaline (ISO)-infused mice. ISO also promoted miR-34c-5p level in primary cultures of neonatal rat cardiomyocytes (NRCMs). Transfection with miR-34c-5p mimic enhanced cell surface area and expression levels of foetal-type genes atrial natriuretic factor (Anf) and β-myosin heavy chain (β-Mhc) in NRCMs. In contrast, treatment with miR-34c-5p inhibitor attenuated ISO-induced hypertrophic responses. Enforced expression of miR-34c-5p by tail intravenous injection of its agomir led to cardiac dysfunction and hypertrophy in mice, whereas inhibiting miR-34c-5p by specific antagomir could protect the animals against ISO-triggered hypertrophic abnormalities. Mechanistically, miR-34c-5p suppressed autophagic flux in cardiomyocytes, which contributed to the development of hypertrophy. Furthermore, the autophagy-related gene 4B (ATG4B) was identified as a direct target of miR-34c-5p, and miR-34c-5p was certified to interact with 3' untranslated region of Atg4b mRNA by dual-luciferase reporter assay. miR-34c-5p reduced the expression of ATG4B, thereby resulting in decreased autophagy activity and induction of hypertrophy. Inhibition of miR-34c-5p abolished the detrimental effects of ISO by restoring ATG4B and increasing autophagy. In conclusion, our findings illuminate that miR-34c-5p participates in ISO-induced cardiac hypertrophy, at least partly through suppressing ATG4B and autophagy. It suggests that regulation of miR-34c-5p may offer a new way for handling hypertrophy-related cardiac dysfunction.

microRNAs signatures as potential biomarkers of structural cardiotoxicity in human-induced pluripotent stem-cell derived cardiomyocytes

Identification of early biomarkers of heart injury and drug-induced cardiotoxicity is important to eliminate harmful drug candidates early in preclinical development and to prevent severe drug effects. The main objective of this study was to investigate the expression of microRNAs (miRNAs) in human-induced pluripotent stem cell cardiomyocytes (hiPSC-CM) in response to a broad range of cardiotoxic drugs. Next generation sequencing was applied to hiPSC-CM treated for 72 h with 40 drugs falling into the categories of functional (i.e., ion channel blockers), structural (changes in cardiomyocytes structure), and general (causing both functional and structural) cardiotoxicants as well as non-cardiotoxic drugs. The largest changes in miRNAs expression were observed after treatments with structural or general cardiotoxicants. The number of deregulated miRNAs was the highest for idarubicin, mitoxantrone, and bortezomib treatments. RT-qPCR validation confirmed upregulation of several miRNAs across multiple treatments at therapeutically relevant concentrations: hsa-miR-187-3p, hsa-miR-146b-5p, hsa-miR-182-5p (anthracyclines); hsa-miR-365a-5p, hsa-miR-185-3p, hsa-miR-184, hsa-miR-182-5p (kinase inhibitors); hsa-miR-182-5p, hsa-miR-126-3p and hsa-miR-96-5p (common some anthracyclines, kinase inhibitors and bortezomib). Further investigations showed that an upregulation of hsa-miR-187-3p and hsa-miR-182-5p could serve as a potential biomarker of structural cardiotoxicity and/or an additional endpoint to characterize cardiac injury in vitro.

MicroRNA-365 regulates human cardiac action potential duration

Abnormalities of ventricular action potential cause malignant cardiac arrhythmias and sudden cardiac death. Here, we aim to identify microRNAs that regulate the human cardiac action potential and ask whether their manipulation allows for therapeutic modulation of action potential abnormalities. Quantitative analysis of the microRNA targetomes in human cardiac myocytes identifies miR-365 as a primary microRNA to regulate repolarizing ion channels. Action potential recordings in patient-specific induced pluripotent stem cell-derived cardiac myocytes show that elevation of miR-365 significantly prolongs action potential duration in myocytes derived from a Short-QT syndrome patient, whereas specific inhibition of miR-365 normalizes pathologically prolonged action potential in Long-QT syndrome myocytes. Transcriptome analyses in these cells at bulk and single-cell level corroborate the key cardiac repolarizing channels as direct targets of miR-365, together with functionally synergistic regulation of additional action potential-regulating genes by this microRNA. Whole-cell patch-clamp experiments confirm miR-365-dependent regulation of repolarizing ionic current I_ks. Finally, refractory period measurements in human myocardial slices substantiate the regulatory effect of miR-365 on action potential in adult human myocardial tissue. Our results delineate miR-365 to regulate human cardiac action potential duration by targeting key factors of cardiac repolarization.

MicroRNA-205-5p targets E2F1 to promote autophagy and inhibit pulmonary fibrosis in silicosis through impairing SKP2-mediated Beclin1 ubiquitination

Silicosis is an occupational disease characterized by extensive pulmonary fibrosis, and the underlying pathological process remains uncertain. Herein, we explored the molecular mechanism by which microRNA‐205‐5p (miR‐205‐5p) affects the autophagy of alveolar macrophages (AMs) and pulmonary fibrosis in mice with silicosis through the E2F transcription factor 1 (E2F1)/S‐phase kinase‐associated protein 2 (SKP2)/Beclin1 axis. Alveolar macrophages (MH‐S cells) were exposed to crystalline silica (CS) to develop an in vitro model, and mice were treated with CS to establish an in vivo model. Decreased Beclin1 and increased SKP2 and E2F1 were identified in mice with silicosis. We silenced or overexpressed miR‐205‐5p, E2F1, SKP2 and Beclin1 to investigate their potential roles in pulmonary fibrosis in vivo and autophagy in vitro. Recombinant adenovirus mRFP‐GFP‐LC3 was transduced into the MH‐S cells to assay autophagic flow. Knocking down Beclin1 promoted pulmonary fibrosis and suppressed the autophagy. Co‐immunoprecipitation and ubiquitination assays suggested that SKP2 induced K48‐linked ubiquitination of Beclin1. Furthermore, chromatin immunoprecipitation‐PCR revealed the site where E2F1 bound to the SKP2 promoter between 1638 bp and 1645 bp. As shown by dual‐luciferase reporter gene assay, the transfection with miR‐205‐5p mimic inhibited the luciferase activity of the wild‐type E2F1 3′untranslated region, suggesting that miR‐205‐5p targeted E2F1. Additionally, miR‐205‐5p overexpression increased autophagy and reduced the pulmonary fibrosis, while overexpression of E2F1 or SKP2 or inhibition of Beclin1 could annul this effect. The current study elucidated that miR‐205‐5p targeted E2F1, thereby inhibiting SKP2‐mediated Beclin1 ubiquitination to promote macrophage autophagy and inhibit pulmonary fibrosis in mice with silicosis.

The Expression of miR-365 in Serum of Hypertension Patients with Left Ventricular Hypertrophy Was Up-Regulated, Which Was Positively Correlated with Left Ventricular Mass Index

Objective

The present study aims to investigate micro ribonucleic acid-365 (miR-365) serum expression and its correlation with left ventricular hypertrophy (LVH) in patients with hypertension (HT).

Methods

Eighty-four patients were selected as study subjects and divided into three groups: the experimental group (n = 28), the observation group (n = 29), and the control group (n = 27). The experimental group included patients with LVH-accompanied HT who were treated in the People's Hospital of Hebei Province between November 2019 and November 2020, the observation group included patients with HT unaccompanied by LVH, and the control group included healthy age and gender-matched subjects who underwent health examinations in our physical examination center. The cardiac echocardiography, 24-h Holter electrocardiogram, and circulating miR-365 levels in all subjects were measured. The differences in circulating miR-365 expression levels among the three groups were compared, and the correlations between the miR-365 expression levels and the blood pressure parameters (24-h mean systolic blood pressure [SBP] and 24-h mean diastolic blood pressure [DBP]), inter-ventricular septal thickness (IVST), left ventricular posterior wall thickness (LVPWT), left ventricular internal diameter (LVID), left ventricular mass (LVM), LVM index (LVMI), and LVH-related indicators were analyzed.

Results

The relative miR-365 expressions in the experimental, observation, and control groups were 2.08 (1.60, 2.34), 0.62 (0.44, 0.83), and 0.66 (0.35, 0.86), respectively. Patient miR-365 expression was significantly higher in the experimental group than in the observation group and the control group; the differences were statistically significant (p < 0.000). Furthermore, miR-365 expression was significantly correlated with SBP, DBP, IVST, LVPWT, LVID, LVM, and LVMI; the greatest correlation was with LVMI. Further univariate linear regression analysis revealed that miR-365 expression was linearly and positively correlated with LVMI and that miRNA-365 expression increased with the LVMI value.

Conclusion

The miR-365 serum expression in patients with LVH-accompanied HT was increased compared with the observation group and the control group and positively correlated with the LVH degree.

Myocardial Infarction: The Protective Role of MiRNAs in Myocardium Pathology

Cardiovascular diseases have been regarded as the leading cause of death around the world, with myocardial infarction (MI) being the most severe form. MI leads to myocardial apoptosis, cardiomyocyte fibrosis, and cardiomyocyte hypertrophy, ultimately leading to heart failure, and death. Micro RNAs (miRNAs) participate in the genesis and progression of myocardial pathology after MI by playing an important regulatory role. This review aims to summarize all available knowledge on the role of miRNAs in the myocardial pathological process after MI to uncover potential major target pathways. In addition, the main therapeutic methods and their latest progress are also reviewed. miRNAs can regulate the main signaling pathways as well as pathological processes. Thus, they have the potential to induce therapeutic effects. Hence, the combination of miRNAs with recently developed exosome nanocomplexes may represent the future direction of therapeutics.

Bone and Muscle Crosstalk in Aging

Osteoporosis and sarcopenia are two age-related diseases that affect the quality of life in the elderly. Initially, they were thought to be two independent diseases; however, recently, increasing basic and clinical data suggest that skeletal muscle and bone are both spatially and metabolically connected. The term “osteosarcopenia” is used to define a condition of synergy of low bone mineral density with muscle atrophy and hypofunction. Bone and muscle cells secrete several factors, such as cytokines, myokines, and osteokines, into the circulation to influence the biological and pathological activities in local and distant organs and cells. Recent studies reveal that extracellular vesicles containing microRNAs derived from senescent skeletal muscle and bone cells can also be transported and aid in regulating bone-muscle crosstalk. In this review, we summarize the age-related changes in the secretome and extracellular vesicle-microRNAs secreted by the muscle and bone, and discuss their interactions between muscle and bone cells during aging.

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.

Autophagy in cardiovascular diseases: role of noncoding RNAs

Cardiovascular diseases (CVDs) remain the world's leading cause of death. Cardiomyocyte autophagy helps maintain normal metabolism and functioning of the heart. Importantly, mounting evidence has revealed that autophagy plays a dual role in CVD pathology. Under physiological conditions, moderate autophagy maintains cell metabolic balance by degrading and recycling damaged organelles and proteins, and it promotes myocardial survival, but excessive or insufficient autophagy is equally deleterious and contributes to disease progression. Noncoding RNAs (ncRNAs) are a class of RNAs transcribed from the genome, but most ncRNAs do not code for functional proteins. In recent years, increasingly, various ncRNAs have been identified, and they play important regulatory roles in the physiological and pathological processes of organisms, as well as in autophagy. Thus, determining whether ncRNA-regulated autophagy plays a protective role in CVDs or promotes their progression can help us to develop ncRNAs as therapeutic targets in autophagy-related CVDs. In this review, we briefly summarize the regulatory roles of several important ncRNAs, including microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs), in the autophagy of various CVDs to provide a theoretical basis for the etiology and pathogenesis of CVDs and develop novel therapies to treat CVDs.

Resveratrol inhibits hypertrophic scars formation by activating autophagy via the miR-4654/Rheb axis

Hypertrophic scars (HSs) are a type of pathological scar which are induced by surgery, burn injuries or trauma during the healing process. Due to the high recurrence rates and strong invasive properties, HSs have become a major clinical issue. Resveratrol has been identified as a potential agent to suppress scar formation; however, the underlying mechanism of action remains unclear. Therefore, the present study aimed to investigate the effect of resveratrol on HS-derived fibroblasts (HSFBs) in vitro. MTT assay was performed to evaluate cell viability following the resveratrol treatment. Western blot and RT-qPCR analysis was used to identify the expression levels and the relationship among autophagic markers, miR-4654 and resveratrol treatment. Finally, GFP-LC3 stable HSFBs cells were generated to further assess the effect of resveratrol. The results revealed that resveratrol significantly induced cell death in a dose-dependent manner and induced autophagy by downregulating the expression levels of Rheb in HSFBs. Notably, microRNA-4654 (miR-4654) was significantly decreased in the HSFBs and re-upregulated by resveratrol treatment dose-dependently. Through the bioinformatic analysis and luciferase assay, miR-4654 was identified to directly target Rheb. Transfection studies showed that miR-4654 negative correlated with Rheb expression, suggesting that the autophagic process may be altered by the miR-4654/Rheb axis under the control of resveratrol. In conclusion, the results of the present study suggested that resveratrol may promote autophagy by upregulating miR-4654, which in turn may suppress Rheb expression via directly binding to the 3′-untranslated region of Rheb. These findings provided a novel insight into the development of potential therapeutic targets for HSs.

Cilostazol alleviate nicotine induced cardiomyocytes hypertrophy through modulation of autophagy by CTSB/ROS/p38MAPK/JNK feedback loop

Nicotine is proved to be an important factor for cardiac hypertrophy. Autophagy is important cell recycling system involved in the regulation of cardiac hypertrophy. Cilostazol, which is often used in the management of peripheral vascular disease. However, the effects of cilostazol on nicotine induced autophagy and cardiac hypertrophy are unclear. Here, we aim to determine the role and molecular mechanism of cilostazol in alleviating nicotine-induced cardiomyocytes hypertrophy through modulating autophagy and the underlying mechanisms. Our results clarified that nicotine stimulation caused cardiomyocytes hypertrophy and autophagy flux impairment significantly in neonatal rat ventricular myocytes (NRVMs), which were evidenced by augments of LC3-II and p62 levels, and impaired autophagosomes clearance. Interestingly, cathepsin B (CTSB) activity decreased dramatically after stimulation with nicotine in NRVMs, which was crucial for substrate degradation in the late stage of autophagy process, and cilostazol could reverse this effect dramatically. Intracellular ROS levels were increased significantly after nicotine exposure. Meanwhile, p38MAPK and JNK were activated after nicotine treatment. By using ROS scavenger N-acetyl-cysteine (NAC) could reverse the effects of nicotine by down-regulation the phosphorylation of p38MAPK and JNK pathways, and pretreatment of specific inhibitors of p38MAPK and JNK could restore the autophagy impairment and cardiomyocytes hypertrophy induced by nicotine. Moreover, CTSB activity of lysosome regained after the treatment with cilostazol. Cilostazol also inhibited the ROS accumulation and the activation of p38MAPK and JNK, which providing novel connection between lysosome CTSB and ROS/p38MAPK/JNK related oxidative stress pathway. This is the first demonstration that cilostazol could alleviate nicotine induced cardiomyocytes hypertrophy through restoration of autophagy flux by activation of CTSB and inhibiting ROS/p38/JNK pathway, exhibiting a feedback loop on regulation of autophagy and cardiomyocytes 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 .

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.

MicroRNAs in Cardiac Hypertrophy

Like other organs, the heart undergoes normal adaptive remodeling, such as cardiac hypertrophy, with age. This remodeling, however, is intensified under stress and pathological conditions. Cardiac remodeling could be beneficial for a short period of time, to maintain a normal cardiac output in times of need; however, chronic cardiac hypertrophy may lead to heart failure and death. MicroRNAs (miRNAs) are known to have a role in the regulation of cardiac hypertrophy. This paper reviews recent advances in the field of miRNAs and cardiac hypertrophy, highlighting the latest findings for targeted genes and involved signaling pathways. By targeting pro-hypertrophic genes and signaling pathways, some of these miRNAs alleviate cardiac hypertrophy, while others enhance it. Therefore, miRNAs represent very promising potential pharmacotherapeutic targets for the management and treatment of cardiac hypertrophy.

A Derivate of Benzimidazole-Isoquinolinone Induces SKP2 Transcriptional Inhibition to Exert Anti-Tumor Activity in Glioblastoma Cells

We have previously shown that compound-7g inhibits colorectal cancer cell proliferation and survival by inducing cell cycle arrest and PI3K/AKT/mTOR pathway blockage. However, whether it has the ability to exert antitumor activity in other cancer cells and what is the exact molecular mechanism for its antiproliferation effect remained to be determined. In the present study, compound-7g exhibited strong activity in suppressing proliferation and growth of glioblastoma cells. The inhibitor selectively downregulated F-box protein SKP2 expression and upregulated cell cycle inhibitor p27, and then resulted in G1 cell cycle arrest. Mechanism analysis revealed that compound-7g also provokes the down-regulation of E2F-1, which acts as a transcriptional factor of SKP2. Further results indicated that compound-7g induced an increase of LC3B-II and p62, which causes a suppression of fusion between autophagosome and lysosome. Moreover, compound-7g mediated autophagic flux blockage promoted accumulation of ubiquitinated proteins and then led to endoplasmic reticulum stress. Our study thus demonstrated that pharmacological inactivation of E2F-1-SKP2-p27 axis is a promising target for restricting cancer progression.

PELI3 mediates pro-tumor actions of down-regulated miR-365a-5p in non-small cell lung cancer

Background

To analyze the relative expression of PELI3 and its mechanistic involvement in the non-small cell lung cancer (NSCLC).

Methods

PELI3 expression in NSCLC tissue samples was determined by the immunohistochemistry. The transcripts abundance of PELI3 was measured with real-time PCR. The protein intensity was analyzed by western blot. The overall survival in respect to PELI3 or miR-365a-5p expression was plotted by the Kaplan–Meier’s analysis. Cell growth was determined by colony formation assay. Cell viability was measured by MTT assay. The migration and invasion were evaluated by wound healing and transwell assay respectively. The regulatory effect of miR-365a-5p on PELI3 was interrogated with luciferase reporter assay. The direct binding between miR-365a-5p and PELI3 was analyzed by pulldown assay.

Results

PELI3 was aberrantly up-regulated in NSCLC both in vivo and in vitro. High level of PELI3 associated with poor prognosis. PELI3-deficiency significantly inhibited cell viability, colony formation, migration and invasion. We further identified that miR-365a-5p negatively regulated PELI3 in this disease. Ectopic expression of miR-365a-5p in both A549 and H1299 phenocopied PELI3-deficiency. Meanwhile, PELI3-silencing significantly abolished the pro-tumoral effect elicited by miR-365a-5p inhibition.

Conclusion

Our results highlighted the importance of dysregulated miR-365a-5p-PELI3 signaling axis in NSCLC.

miR-181b-5p suppresses starvation-induced cardiomyocyte autophagy by targeting Hspa5

This study aimed to investigate the role of microRNA-181b-5p (miR-181b-5p) in starvation-induced cardiomyocyte autophagy by targeting heat shock protein family A member 5 (Hspa5). For this purpose, H9c2 cardiomyocytes and neonatal rat ventricular myocytes (NRVMs) were glucose-starved in Earle's Balanced Salt Solution (EBSS) for different periods of time (0, 2, 4, 6 and 8 h). RT-qPCR analysis was performed to examine the expression of miR-181b-5p in the different groups. Immunofluorescence was performed to detect the expression of LC3. In addition, the H9c2 cardiomyo-cytes and NRVMs were transfected with miR-181b-5p mimic, miR-181b-5p inhibitor, siHspa5 or their respective controls. An MTT assay was performed to measure cell proliferation in the different groups. Western blot analysis was performed to determine the expression of Beclin-1, Hspa5, phosphorylated phosphoinositide 3-kinase PI3K (p-PI3K), phosphorylated Akt (p-Akt), phosphorylated mammalian target of rapamycin (p-mTOR), Bcl-2, Bax and cleaved caspase-3. Flow cytometry was performed to assess cell apoptosis. A luciferase reporter assay was performed to determine whether Hspa5 is a direct target of miR-181b-5p. The results revealed that the down-regulation of miR-181b-5p promoted cell autophagy in the cardiomyocytes. Moreover, miR-181b-5p negatively regulated Beclin-1 and Hspa5. Beclin-1 is a well-known autophagy- and apoptosis-related protein. In addition, cell apoptosis was attenuated by the decreased expression of miR-181b-5p in the cardiomyocytes. Bcl-2 prevented apoptosis and autophagy by binding to Bax and Bcl-2, respectively. The upregulation of miR-181b-5p inhibited autophagy and promoted apoptosis via Hspa5. miR-181b-5p inhibition promoted p-mTOR, p-Akt and p-PI3K expression via Hspa5. The results of luciferase reporter assay also confirmed that Hspa5 is a direct target of miR-181b-5p. On the whole, the findings of this study suggest that miR-181b-5p contributes to starvation-induced autophagy and apoptosis in cardiomyocytes by directly targeting Hspa5 via the PI3K/Akt/mTOR signaling pathway.

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

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

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.

Rottlerin promotes autophagy and apoptosis in gastric cancer cell lines

It is widely accepted that apoptosis is closely associated with cancer cell death. However, whether autophagy induces tumor cell death has not been fully elucidated. Various studies have discussed the antitumor properties of rottlerin in human malignancies. The current study aimed to investigate the effects of rottlerin, a natural product isolated from the kamala tree (Mallotus philipensis), on growth inhibition and autophagy in gastric cancer (GC) cell lines in vitro. The results of the present study demonstrated that rottlerin suppressed cell growth, induced autophagy and apoptosis, and reduced migration and invasion in the SGC-7901 and MGC-803 GC cell lines. Furthermore, rottlerin led to microtubule-associated protein 1 light chain 3β-II augmentation and the enrichment of autophagosomes. In addition, the protein expression levels of mechanistic target of rapamycin kinase and S-phase kinase-associated protein 2 were downregulated in GC cells following rottlerin treatment, which is associated with autophagy. The protein levels of caspase-3, cleaved-caspase-3, total poly (ADP-ribose) polymerase (PARP) and cleaved-PARP exhibited no marked alterations in the GC cells following rottlerin treatment, indicating that caspases were likely not involved in rottlerin-induced GC apoptosis. In summary, the results of the present study indicate that rottlerin may inhibit invasion and promote apoptosis in GC cells, which may be mediated by the activation of autophagy. Therefore, rottlerin may be of value in the treatment of GC.

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

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

The Role and Molecular Mechanism of Non-Coding RNAs in Pathological Cardiac Remodeling

Non-coding RNAs (ncRNAs) are a class of RNA molecules that do not encode proteins. Studies show that ncRNAs are not only involved in cell proliferation, apoptosis, differentiation, metabolism and other physiological processes, but also involved in the pathogenesis of diseases. Cardiac remodeling is the main pathological basis of a variety of cardiovascular diseases. Many studies have shown that the occurrence and development of cardiac remodeling are closely related with the regulation of ncRNAs. Recent research of ncRNAs in heart disease has achieved rapid development. Thus, we summarize here the latest research progress and mainly the molecular mechanism of ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), in cardiac remodeling, aiming to look for new targets for heart disease treatment.