Down-regulation of miR-200c attenuates AngII-induced cardiac hypertrophy via targeting the MLCK-mediated pathway

Bisphenol A exposure exacerbates tracheal inflammatory injury in selenium-deficient chickens by regulating the miR-155/TRAF3/ROS pathway

Bisphenol A (BPA) is an endocrine disruptor. Excessive BPA intake can damage the structure and function of the respiratory tract. Dietary selenium (Se) deficiency may also cause immune tissue damage. To investigate the potential mechanism of BPA on tracheal damage in selenium-deficient chickens and the role of microRNAs (miRNAs) in this process, we established in vitro and in vivo Se deficiency and BPA exposure models and screened out miR-155 for follow-up experiments. We further predicted and confirmed the targeting relationship between miR-155 and TRAF3 using TargetScan and dual luciferase assays and found that miR-155 was highly expressed and caused inflammatory damage. Further studies showed that BPA exposure increased airway oxidative stress, activated the NF-κB pathway, and caused inflammation and immune damage in selenium-deficient chickens, but down-regulating miR-155 and NAC treatment could reverse this phenomenon. This suggested that these pathways are regulated by the miR-155/TRAF3/ROS axis. In conclusion, BPA exposure aggravates airway inflammation in selenium-deficient chickens by regulating miR-155/TRAF3/ROS. This study revealed the mechanism of BPA exposure combined with Se deficiency in tracheal inflammatory injury in chickens and enriched the theoretical basis of BPA injury in poultry.

Histone demethylase KDM3C regulates the lncRNA GAS5-miR-495-3p-PHF8 axis in cardiac hypertrophy

Cardiac hypertrophy (CH) is a pathological phenotype of cardiomyopathy. Epigenetic modification is a mechanism associated with CH. Our study here investigated the histone demethylase KDM3C in relation to epigenetic regulation in CH. We found that KDM3C mRNA silencing alleviated CH, as evidenced by reduced ANP, BNP, and β-MHC mRNAs, increased α-MHC mRNA, decreased cell surface area, and reduced cellular protein/DNA ratios. Specifically, KDM3C upregulated miR-200c-3p expression through demethylation of H3K9me2, leading to enhanced binding of miR-200c-3p to GAS5 and suppression of GAS5 expression; these effects then led to reduced binding of GAS5 to miR-495-3p, increased miR-495-3p expression, and repression of PHF8 transcription. Through these mechanisms, our data indicate that KDM3C-dependent epigenetic modification promotes CH.

lncRNA NBR2 attenuates angiotensin II-induced myocardial hypertrophy through repressing ER stress via activating LKB1/AMPK/Sirt1 pathway

Myocardial hypertrophy leads to heart failure (HF), and emerging researchers have illustrated that long noncoding RNAs (lncRNAs) modulate myocardial hypertrophy. Here, we explored the role and mechanism of a novel lncRNA, NBR2, in modulating angiotensin II (Ang II)-induced myocardial hypertrophy. First, we examined plasma NBR2 levels in 25 patients with HF and myocardial hypertrophy and ten healthy donors and analyzed the correlation between NBR2 profiles and patients’ clinical indicators. In addition, the overexpression experiment of NBR2 was carried out to probe the influence of NBR2 on myocardial hypertrophy. lncRNA NBR2 was down-regulated in plasma of patients with HF and myocardial hypertrophy (vs. healthy controls), and its level was negatively correlated with cardiac function (represented by left ventricular end-diastolic diameter and left ventricular ejection fraction) and degree of myocardial hypertrophy. Besides, Ang II treatment intensified the hypertrophy of human myocardial cell lines (HCM and AC16) and curbed the NBR2 expression. Overexpressing lncRNA NBR2 alleviated Angiotension II–induced myocardial hypertrophy and declined the profiles of hypertrophic markers. Moreover, up-regulating lncRNA NBR2 weakened Ang II-mediated endoplasmic reticulum (ER) stress and activated the LKB1/AMPK/Sirt1 pathway. Interfering with the LKB1/AMPK/Sirt1 axis abated the lncRNA NBR2-mediated inhibitory effect on myocardial hypertrophy and ER stress. This study confirmed that lncRNA NBR2 dampened myocardial hypertrophy and ER stress by modulating the LKB1/AMPK/Sirt1 pathway. Our study provides the first evidence that lncRNA NBR2 is positively associated with myocardial hypertrophy.

Loss of cardiac myosin light chain kinase contributes to contractile dysfunction in right ventricular pressure overload

Nearly 1 in every 100 children born have a congenital heart defect. Many of these defects primarily affect the right heart causing pressure overload of the right ventricle (RV). The RV maintains function by adapting to the increased pressure; however, many of these adaptations eventually lead to RV hypertrophy and failure. In this study, we aim to identify the cellular and molecular mechanisms of these adaptions. We utilized a surgical animal model of pulmonary artery banding (PAB) in juvenile rats that has been shown to accurately recapitulate the physiology of right ventricular pressure overload in young hearts. Using this model, we examined changes in cardiac myocyte protein expression as a result of pressure overload with mass spectrometry 4 weeks post-banding. We found pressure overload of the RV induced significant downregulation of cardiac myosin light chain kinase (cMLCK). Single myocyte calcium and contractility recordings showed impaired contraction and relaxation in PAB RV myocytes, consistent with the loss of cMLCK. In the PAB myocytes, calcium transients were of smaller amplitude and decayed at a slower rate compared to controls. We also identified miR-200c, which has been shown to regulate cMLCK expression, as upregulated in the RV in response to pressure overload. These results indicate the loss of cMLCK is a critical maladaptation of the RV to pressure overload and represents a novel target for therapeutic approaches to treat RV hypertrophy and failure associated with congenital heart defects.

MicroRNA miR-27a-3p accelerates cardiac hypertrophy by targeting neuro-oncological ventral antigen 1

MiRNAs are a class of small non-coding RNAs (ncRNAs) responsible for post-transcriptional regulation of target genes. Accumulating evidence indicates that miRNAs are implicated in the progression of cardiac hypertrophy. Therefore, understanding the molecular mechanisms how these miRNAs regulate cardiac hypertrophy is useful for diagnosis and monitoring of disease progression. In this study, to investigate the effect of miR-27a-3p, we established an in vitro cardiac hypertrophy model by treating H9c2 cardiomyocytes with angiotensin II (Ang II) and an in vivo model through the chronic infusion of Ang II into mice. As revealed by our experimental results, miR-27a-3p expression was significantly increased in clinical samples, animal and cell models of cardiac hypertrophy. Inhibiting miR-27a-3p mitigated cardiac hypertrophy phenotype induced by Ang II. Additionally, our work identified NOVA1 (neuro-oncological ventral antigen 1) as a downstream target of miR-27a-3p. miR-27a-3p overexpression reduced NOVA1 protein level and mRNA expression. Consistently, NOVA1 silencing promoted cardiac hypertrophy phenotype induced by Ang II. In summary, these results suggest that the upregulation of miR-27a-3p may serve as a diagnostic factor for cardiac hypertrophy, and miR-27a-3p upregulation promotes cardiac hypertrophy by targeting NOVA1.

Myosin Light Chain Kinase Modulates to Improve Myocardial Hypoxia/Reoxygenation Injury

Objective

The aim of this study was to evaluate whether myosin light chain kinase (MLCK) knockdown attenuated H9C2 cell hypoxia/reoxygenation (H/R) injury and downstream signaling pathway.

Methods

The MLCK expression in H/R injury model H9C2 cell was determined by western blot and qRT-PCR. H/R cells were transfected with si-MLCK in the presence of P38 inhibitor (SB203580) or ERK inhibitor (U0126). Then, cell apoptosis was verified by flow cytometry. Apoptosis-related proteins were detected by western blot. The contents of reactive oxygen species (ROS), lactate dehydrogenase (LDH), superoxide dismutase (SOD), interleukin-6 (IL-6), interleukin (IL)-1β (IL-1β), and tumor necrosis factor-α (TNF-α) were measured using flow cytometry and colorimetric assays, respectively.

Results

MLCK expression was higher in H/R cells. Knockdown of MLCK diminished the amounts of ROS, LDH, IL-6, IL-1β, and TNF-α and elevated the release of SOD in H/R model H9C2 cells. Additionally, H/R injury induced the cumulative expression and phosphorylation of ERK and the phosphorylation of P38, whereas MLCK siRNA-treated cells showed decreased ERK1/2 and P38 activation. Inversely, P38 inhibitor (SB203580) and ERK inhibitor (U0126) could reverse the cardioprotective effects induced by si-MLCK.

Conclusion

MLCK knockdown attenuated H/R injury in H9C2 cells via regulating the ERK/P38 signaling pathway. MLCK/ERK/p38 axis may provide novel insight into therapeutic targets to restrain I/R injury caused by revascularization therapy after acute myocardial infarction.

Postbiotics derived from Lactobacillus plantarum 1.0386 Ameliorates lipopolysaccharide-induced tight junction injury via MicroRNA-200c-3p Mediated Activation of MLCK-MLC Pathway in Caco-2 Cells

L. plantarum 1.0386 could repair the intestinal epithelial tight junction injury, and the present study was designed to further explore the role of its postbiotics, including surface protein (1.0386-Slp), peptidase...

Vasorin deficiency leads to cardiac hypertrophy by targeting MYL7 in young mice

Vasorin (VASN) is an important transmembrane protein associated with development and disease. However, it is not clear whether the death of mice with VASN deficiency (VASN^-/- ) is related to cardiac dysfunction. The aim of this research was to ascertain whether VASN induces pathological cardiac hypertrophy by targeting myosin light chain 7 (MYL7). VASN^-/- mice were produced by CRISPR/Cas9 technology and inbreeding. PCR amplification, electrophoresis, real-time PCR and Western blotting were used to confirm VASN deficiency. Cardiac hypertrophy was examined by blood tests, histological analysis and real-time PCR, and key downstream factors were identified by RNA sequencing and real-time PCR. Western blotting, immunohistochemistry and electron microscopy analysis were used to confirm the downregulation of MYL7 production and cardiac structural changes. Our results showed that sudden death of VASN^-/- mice occurred 21-28 days after birth. The obvious increases in cardiovascular risk, heart weight and myocardial volume and the upregulation of hypertrophy marker gene expression indicated that cardiac hypertrophy may be the cause of death in young VASN^-/- mice. Transcriptome analysis revealed that VASN deficiency led to MYL7 downregulation, which induced myocardial structure abnormalities and disorders. Our results revealed a pathological phenomenon in which VASN deficiency may lead to cardiac hypertrophy by downregulating MYL7 production. However, more research is necessary to elucidate the underlying mechanism.

TFEC contributes to cardiac hypertrophy by inhibiting AMPK/mTOR signaling

The underlying mechanism of cardiac hypertrophy has not yet been fully elucidated. The present study aimed to explore the function of transcription factor EC (TFEC) in mouse models of cardiac hypertrophy and to determine the underlying mechanism. Pressure-overload cardiac hypertrophy and angiotensin II (AngII) infusion-induced animal models of cardiac hypertrophy were established in vivo. The expression of TFEC was explored via western blotting. The results demonstrated that TFEC expression was significantly increased in the hearts of mice with pressure overload- and AngII-induced hypertrophy. Injection of rAd-short hairpin (sh)-TFEC significantly decreased the expression of TFEC in heart tissues compared with group injected with rAd-negative control (NC). Furthermore, the expression levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC) were increased in the hearts of AngII-treated mice; however, compared with rAd-NC transfection, transfection with rAd-sh-TFEC decreased the expression levels of ANP, BNP and β-MHC. The results from echocardiographic analysis indicated that transfection with rAd-sh-TFEC improved the cardiac function of AngII-treated mice compared with transfection with rAd-NC. In addition, the AngII-induced increase in cardiomyocyte size could be reversed by TFEC knockdown in primary cardiomyocytes. The elevated expression levels of ANP, BNP and β-MHC induced by AngII could be partially abolished following TFEC knockdown. The results from western blotting demonstrated that TFEC overexpression decreased the expression of phosphorylated AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) but increased the expression of phosphorylated mechanistic target of rapamycin (mTOR). Furthermore, Compound C significantly suppressed the activation of AMPK/ACC but increased the activation of mTOR, even in primary cardiomyocytes transfected with rAd-sh-TFEC. In conclusion, the findings from this study demonstrated that TFEC was overexpressed in the hearts of mice with cardiac hypertrophy and that silencing TFEC may improve AngII-induced cardiac hypertrophy and dysfunction by activating AMPK/mTOR signaling.

Amniotic fluid microRNA profiles in twin-twin transfusion syndrome with and without severe recipient cardiomyopathy

BACKGROUND

Twin-twin transfusion syndrome presents many challenges for clinicians, and the optimal means of identifying pregnancies that will benefit most from intervention is controversial. There is currently no clinically available biomarker to detect twin-twin transfusion syndrome or to stratify cases based on the risk factors. microRNAs are small RNAs that regulate gene expression and are biomarkers for various disease processes, including adult and pediatric heart failure. To date, no studies have investigated amniotic fluid microRNAs as biomarkers for disease severity, specifically for severe recipient cardiomyopathy in twin-twin transfusion syndrome cases.

OBJECTIVE

This study aimed to assess whether amniotic fluid microRNAs could be useful as biomarkers to identify pregnancies at greatest risk for severe recipient cardiomyopathy associated with twin-twin transfusion syndrome.

STUDY DESIGN

Amniotic fluid was collected at the time of amnioreduction or selective fetoscopic laser photocoagulation from monochorionic diamniotic twin pregnancies with twin-twin transfusion syndrome at any stage. Fetal echocardiography was performed on all twins before the procedure, and severe cardiomyopathy was defined as a right ventricular myocardial performance index of the recipient fetus of >4 Z-scores. microRNA was extracted from the amniotic fluid samples and analyzed using an array panel assessing 379 microRNAs (TaqMan Open Array, ThermoFisher). Student t tests were performed to determine significant differences in microRNA expression between pregnancies with severe recipient cardiomyopathy and those with preserved cardiac function. A stringent q value of <.0025 was used to determine differential microRNA expression. Random forest plots identified the top 3 microRNAs that separated the 2 groups, and hierarchical cluster analysis was used to determine if these microRNAs properly segregated the samples according to their clinical groups.

RESULTS

A total of 14 amniotic fluid samples from pregnancies with twin-twin transfusion syndrome with severe cardiomyopathy were compared with samples from 12 twin-twin transfusion syndrome control cases with preserved cardiac function. A total of 110 microRNAs were identified in the amniotic fluid samples. Twenty microRNAs were differentially expressed, and the top 3 differentiating microRNAs were hsa-miR-200c-3p, hsa-miR-17-5p, and hsa-miR-539-5p. Hierarchical cluster analysis based on these top 3 microRNAs showed a strong ability to differentiate severe cardiomyopathy cases from controls. The top 3 microRNAs were used to investigate the sensitivity and specificity of these microRNAs to differentiate between the 2 groups with a receiver operating characteristic curve demonstrating sensitivity and specificity of 80.8%. All 20 differentially expressed microRNAs were down-regulated in the group with severe cardiomyopathy.

CONCLUSION

Amniotic fluid microRNAs demonstrated differential expression between twin-twin transfusion syndrome recipient fetuses with severe cardiomyopathy and those without and have the potential to be important biomarkers of disease severity in this population.

Depletion of miR-155 hinders the myofibroblast activities and reactive oxygen species generation in oral submucous fibrosis

BACKGROUND/PURPOSE

Emerging evidence suggests the significance of microRNA-155 (miR-155) in fibrogenesis and oxidative stress accumulation, but its function in oral submucous fibrosis (OSF) has not been investigated. In this study, we assessed the expression of miR-155 and its effects on the maintenance of myofibroblast activation.

METHODS

qRT-PCR was conducted to assess the expression of miR-155 in OSF tissues and fibrotic buccal mucosal fibroblasts (fBMFs) derived from OSF samples. Collagen gel contraction, migration, and invasion capabilities were examined in fBMFs. DCFDA ROS assay was used to examine ROS generation. A luciferase reporter assay was carried out to verify the relationship between miR-155 and its potential target RPTOR.

RESULTS

We showed that the expression of miR-155 was aberrantly upregulated in OSF specimens and fBMFs. Inhibition of miR-155 ameliorated various myofibroblast activities, including collagen gel contraction, migration, and invasion abilities as well as ROS production. Results from the luciferase reporter assay demonstrated that miR-155 directly interacted with its target RPTOR.

CONCLUSION

Taken together, these findings indicate that miR-155 is implicated in the pathogenesis of oxidative stress-associated OSF, possibly through the regulation of RPTOR.

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.

Piperine protects against myocardial ischemia/reperfusion injury by activating the PI3K/AKT signaling pathway

Piperine (PIP) exerts numerous pharmacological effects and its involvement in endoplasmic reticulum (ER) stress (ERS)-led apoptosis has garnered attention. The present study focused on whether PIP played protective effects on hypoxia/reoxygenation (H/R)-induced cardiomyocytes by repressing ERS-led apoptosis. The potential molecular mechanisms in association with the PI3K/AKT signaling pathway were investigated. Primary neonatal rat cardiomyocytes (NRCMs) were isolated and randomized into four groups: Control + vehicle group, control + PIP group, H/R + vehicle group and H/R + PIP group. The H/R injury model was constructed by 4 h of hypoxia induction followed by 6 h of reoxygenation. A total of 10 µM PI3K/AKT inhibitor LY294002 was supplemented to the cells during the experiments. Cell viability and myocardial enzymes were detected to evaluate myocardial damage. A flow cytometry assay was performed to assess apoptotic response. Western blot analysis was performed to detect the expression of related proteins including PI3K, AKT, CHOP, GRP78 and cleaved caspase-12. The results showed that H/R markedly promoted myocardial damage as shown by the increased release of lactate dehydrogenase and creatine kinase levels, but a reduction in cell viability. In addition, ERS-induced apoptosis was markedly promoted by H/R in NRCMs, as shown by the increased apoptotic rates and expression of C/EBP-homologous protein, endoplasmic reticulum chaperone BiP and caspase-12. PIP administration reversed cell injury and ERS-induced apoptosis in H/R. Mechanistic studies concluded that the apoptosis-inhibitory contributions and cardio-favorable effects of PIP were caused partly by the activation of the PI3K/AKT signaling pathway, which was verified by LY294002 administration. To conclude, PIP can reduce ERS-induced apoptosis by activating the PI3K/AKT signaling pathway during the process of H/R injury, which could be a potential therapeutic target for the treatment of myocardial ischemia/reperfusion injury.

miR-4286/TGF-β1/Smad3-Negative Feedback Loop Ameliorated Vascular Endothelial Cell Damage by Attenuating Apoptosis and Inflammatory Response

Atherosclerosis (AS), known as the chronic inflammatory disease, results from the dysfunction of vascular endothelial cells (VECs). Transforming growth factor-β1 (TGF-β1) has been reported to be induced by oxidized low-density lipoprotein (ox-LDL) and contribute to AS-related vascular endothelial cell damage. This work planned to study the mechanism of TGF-β1 in vascular endothelial cell damage. We found that TGF-β1 was activated by ox-LDL in human umbilical vascular endothelial cells (HUVECs). Silence of TGF-β1 reversed the inductive effect of ox-LDL on apoptosis and inflammatory response of HUVECs. Mechanistically, microRNA-4286 (miR-4286) targeted and inhibited TGF-β1 to inhibit Smad3, and Smad3 bound to the promoter of miR-4286 to repress its transcription. Rescue assays indicated that miR-4286 ameliorated the ox-LDL-induced apoptosis and inflammatory response through inhibiting TGF-β1. In conclusion, our study first demonstrated that miR-4286/TGF-β1/Smad3-negative feedback loop ameliorated vascular endothelial cell damage by attenuating apoptosis and inflammatory response, providing new thoughts for promoting the treatment of AS.

MicroRNA and ROS Crosstalk in Cardiac and Pulmonary Diseases

Reactive oxygen species (ROS) affect many cellular functions and the proper redox balance between ROS and antioxidants contributes substantially to the physiological welfare of the cell. During pathological conditions, an altered redox equilibrium leads to increased production of ROS that in turn may cause oxidative damage. MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level contributing to all major cellular processes, including oxidative stress and cell death. Several miRNAs are expressed in response to ROS to mediate oxidative stress. Conversely, oxidative stress may lead to the upregulation of miRNAs that control mechanisms to buffer the damage induced by ROS. This review focuses on the complex crosstalk between miRNAs and ROS in diseases of the cardiac (i.e., cardiac hypertrophy, heart failure, myocardial infarction, ischemia/reperfusion injury, diabetic cardiomyopathy) and pulmonary (i.e., idiopathic pulmonary fibrosis, acute lung injury/acute respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, lung cancer) compartments. Of note, miR-34a, miR-144, miR-421, miR-129, miR-181c, miR-16, miR-31, miR-155, miR-21, and miR-1/206 were found to play a role during oxidative stress in both heart and lung pathologies. This review comprehensively summarizes current knowledge in the field.

MiR-30e-5p is sponged by Kcnq1ot1 and represses Angiotensin II-induced hypertrophic phenotypes in cardiomyocytes by targeting ADAM9

Prolonged cardiac hypertrophy, a pathological compensatory response of the heart, finally leads to heart failure. Numerous studies have illustrated the vital roles of non-coding RNAs (ncRNAs) in cardiac hypertrophy. Here, we probed into the role and probable mechanism of microRNA-30e-5p (miR-30e-5p) in Angiotensin II (Ang-II)-stimulated hypertrophic cardiomyocytes. Intriguingly, the expression of hypertrophic markers, cell surface area and protein/DNA ratio were all reduced in Ang-II-induced hypertrophic cardiomyocytes when miR-30e-5p expression was augmented. Then, ADAM9 was screened out as the target of miR-30e-5p and ADAM9 overexpression rescued the effect of miR-30e-5p upregulation in Ang-II-treated cardiomyocytes. Moreover, we identified Kcnq1ot1 as the upstream of miR-30e-5p/ADAM9 axis and verified that Kcnq1ot1 aggrandized ADAM9 expression in Ang-II-treated cardiomyocytes through absorbing miR-30e-5p. Furthermore, rescue assays confirmed that ADAM9 up-regulation abrogated the repressive effect of Kcnq1ot1 depletion on Ang-II-induced cardiac hypertrophy. In conclusion, Kcnq1ot1 sequestered miR-30e-5p to release ADAM9 to facilitate cardiac hypertrophy, indicating that Kcnq1ot1 might be used as a potentially therapeutic target for cardiac hypertrophy.

Up-regulation of miR-195 contributes to cardiac hypertrophy-induced arrhythmia by targeting calcium and potassium channels

Previous studies have confirmed that miR-195 expression is increased in cardiac hypertrophy, and the bioinformatics website predicted by Targetscan software shows that miR-195 can directly target CACNB1, KCNJ2 and KCND3 to regulate Cavβ1, Kir2.1 and Kv4.3 proteins expression. The purpose of this study is to confirm the role of miR-195 in arrhythmia caused by cardiac hypertrophy. The protein levels of Cavβ1, Kir2.1 and Kv4.3 in myocardium of HF mice were decreased. After miR-195 was overexpressed in neonatal mice cardiomyocytes, the expression of ANP, BNP and β-MHC was up-regulated, and miR-195 inhibitor reversed this phenomenon. Overexpression of miR-195 reduced the estimated cardiac function of EF% and FS% in wild-type (WT) mice. Transmission electron microscopy showed that the ultrastructure of cardiac tissues was damaged after miR-195 overexpression by lentivirus in mice. miR-195 overexpression increased the likelihood of arrhythmia induction and duration of arrhythmia in WT mice. Lenti-miR-195 inhibitor carried by lentivirus can reverse the decreased EF% and FS%, the increased incidence of arrhythmia and prolonged duration of arrhythmia induced by TAC in mice. After miR-195 treatment, the protein expressions of Cavβ1, Kir2.1 and Kv4.3 were decreased in mice. The results were consistent at animal and cellular levels, respectively. Luciferase assay results showed that miR-195 may directly target CACNB1, KCNJ2 and KCND3 to regulate the expression of Cavβ1, Kir2.1 and Kv4.3 proteins. MiR-195 is involved in arrhythmia caused by cardiac hypertrophy by inhibiting Cavβ1, Kir2.1 and Kv4.3.

MiR-625-5p Inhibits Cardiac Hypertrophy Through Targeting STAT3 and CaMKII

Cardiac hypertrophy is an adaptive cardiac response to heart stress. Sustained cardiac hypertrophy indicates higher risk of heart failure. Ca2+/calmodulin-dependent protein kinase II (CaMKII) has been proved to be a key regulator of cardiac hypertrophy, but its mechanism remains largely unknown. Our study proposed to explore the regulatory mechanism of CaMKII in cardiac hypertrophy. We validated that CaMKII was upregulated in cardiac hypertrophy models in vivo and in vitro and that knockdown of CaMKII attenuated Ang II-induced cardiac hypertrophy in vitro. Furthermore, we demonstrated that signal transducer and activator of transcription 3 (STAT3) was highly expressed in cardiac hypertrophy and could stimulate the transactivation of CaMKII. Moreover, we predicted through TargetScan and confirmed that miR-625-5p targeted and inhibited STAT3 so as to reduce the expression of CaMKII. Interestingly, we also found that miR-625-5p directly targeted CaMKII and inhibited its expression. Rescue assays suggested that miR-625-5p attenuated Ang II-induced cardiac hypertrophy through CaMKII/STAT3. Consequently, this study elucidated that miR-625-5p inhibited cardiac hypertrophy through targeting STAT3 and CaMKII, suggesting miR-625-5p as a novel negative regulator of cardiac hypertrophy. Graphical abstract [Figure: see text].

The Oxidative Stress-Induced miR-200c Is Upregulated in Psoriasis and Correlates with Disease Severity and Determinants of Cardiovascular Risk

Psoriasis is a chronic inflammatory skin disease associated with reactive oxygen species (ROS) increase and a higher risk of cardiovascular (CV) events. We previously showed that the miR-200 family (miR-200s) is induced by ROS, miR-200c being the most upregulated member responsible for apoptosis, senescence, ROS increase, and nitric oxide decrease, finally causing endothelial dysfunction. Moreover, circulating miR-200c increases in familial hypercholesterolemic children and in plaques and plasma of atherosclerotic patients, two pathologies associated with increased ROS. Given miR-200s' role in endothelial dysfunction, ROS, and inflammation, we hypothesized that miR-200s were modulated in lesional skin (LS) and plasma of psoriatic patients (Pso) and that their levels correlated with some CV risk determinants at a subclinical level. All Pso had severe psoriasis, i.e., Psoriasis Area and Severity Index (PASI) > 10, and one of the following: at least two systemic psoriasis treatments, age at onset < 40 years, and disease duration > 10 years. RNA was extracted from plasma (Pso, N = 29; Ctrl, N = 29) and from nonlesional skin (NLS) and LS of 6 Pso and 6 healthy subject skin (HS) biopsies. miR-200 levels were assayed by quantitative RT-PCR. We found that all miR-200s were increased in LS vs. NLS and miR-200c was the most expressed and upregulated in LS vs. HS. In addition, circulating miR-200c and miR-200a were upregulated in Pso vs. Ctrl. Further, miR-200c positively correlated with PASI, disease duration, left ventricular (LV) mass, LV relative wall thickness (RWT), and E/e', a marker of diastolic dysfunction. Multiple regression analysis indicates a direct association between miR-200c and both RWT and LV mass. Circulating miR-200a correlated positively only with LV mass and arterial pressure augmentation index, a measure of stiffness, although the correlations were nearly significant (P = 0.06). In conclusion, miR-200c is upregulated in LS and plasma of Pso, suggesting its role in ROS increase and inflammation associated with CV risk in psoriasis.

Long Noncoding RNA FTX Reduces Hypertrophy of Neonatal Mouse Cardiac Myocytes and Regulates the PTEN/PI3K/Akt Signaling Pathway by Sponging MicroRNA-22

BACKGROUND Cardiac myocyte hypertrophy results from clinical conditions that include hypertension and valvular heart disease, and can result in heart failure. This study aimed to investigate the expression and role of the long noncoding RNA FTX (lnc-FTX), an X-inactive-specific transcript (XIST) regulator transcribed from the X chromosome, in hypertrophy of neonatal mouse cardiac myocytes induced by angiotensin II (Ang II) in vitro. MATERIAL AND METHODS Cardiac myocytes were isolated from neonatal mice and cultured with and without Ang II. Immunofluorescence, with localization of an antibody to alpha-smooth muscle actin (alpha-SMA), was used to identify the neonatal mouse cardiac myocytes. Quantitative real-time polymerase chain reaction (qRT-PCR) measured gene expression levels. The cell counting kit-8 (CCK-8) assay was used to determine cell viability, and Western blot measured protein expression. StarBase v2.0 bioinformatics software was used for target gene prediction and was confirmed with the luciferase reporter assay. RESULTS The expression of lnc-FTX was reduced in mouse cardiac myocytes treated with Ang II. Overexpression of lnc-FTX reduced cell apoptosis, cardiomyocyte contractility, and the expression of c-Jun, A-type natriuretic peptide (ANP), and B-type natriuretic peptide (BNP) induced by Ang II. The target of lnc-FTX was micro-RNA 22 (miRNA-22). The mechanism of action of lnc-FTX in neonatal mouse cardiac myocytes was through suppression of the PI3K/Akt signaling pathway by promoting the release of PTEN by sponging miRNA-22. CONCLUSIONS The expression of lnc-FTX was associated with reduced hypertrophy of neonatal mouse cardiac myocytes and regulated the PTEN/PI3K/Akt signaling pathway by sponging miRNA-22.

MD-1 Deficiency Accelerates Myocardial Inflammation and Apoptosis in Doxorubicin-Induced Cardiotoxicity by Activating the TLR4/MAPKs/Nuclear Factor kappa B (NF-κB) Signaling Pathway

Background

Myocardial apoptosis and inflammation play important roles in doxorubicin (DOX)-caused cardiotoxicity. Our prior studies have characterized the effects of myeloid differentiation protein 1(MD-1) in pathological cardiac remodeling and myocardial ischemia/reperfusion (I/R) injury, but its participations and potential molecular mechanisms in DOX-caused cardiotoxicity remain unknown.

Material/Methods

In the present study, MD-1 knockout mice were generated, and a single intraperitoneal injection of DOX (15 mg/kg) was performed to elicit DOX-induced cardiotoxicity. Cardiac function, histological change, mitochondrial structure, myocardial death, apoptosis, inflammation, and molecular alterations were measured systemically.

Results

The results showed that the protein and mRNA levels of MD-1 were dramatically downregulated in DOX-treated cardiomyocytes. DOX insult markedly accelerated cardiac dysfunction and injury, followed by enhancements of apoptosis and inflammation, all of which were further aggravated in MD-1 knockout mice. Mechanistically, the TLR4/MAPKs/NF-κB pathways, which were over-activated in MD-1-deficient mice, were significantly increased in DOX-damaged cardiomyocytes. Moreover, the abolishment of TLR4 or NF-κB via a specific inhibitor exerted protective effects against the adverse effects of MD-1 loss on DOX-caused cardiotoxicity.

Conclusions

Collectively, these findings suggest that MD-1 is a novel target for the treatment of DOX-induced cardiotoxicity.

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.

Down-regulation of miR-200c attenuates AngII-induced cardiac hypertrophy via targeting the MLCK-mediated pathway

Background

MicroRNAs (miRNAs) have been shown to commonly contribute to cardiac hypertrophy (CH). The aim of this study was to test the hypothesis that miR‐200c plays an important role in the progression of CH by targeting myosin light chain kinase (MLCK/MYLK).

Methods and results

Cardiac hypertrophy was induced by aortic banding (AB) in rats. Cellular hypertrophy in neonatal rat cardiomyocytes (NCMs) was induced by AngII treatment. Echocardiography, histology and molecular measurements were used to assess the results of the experiments. The levels of apoptosis and reactive oxygen species (ROS) were also measured. Quantitative real‐time PCR (qRT‐PCR) and Western blotting were used to measure mRNA and protein levels respectively. The present results showed that miR‐200c expression was increased in response to CH both in vivo and in vitro. The down‐regulation of miRNA‐200c by a specific inhibitor markedly ameliorated CH resulting from AngII treatment, and the mRNA levels of atrial natriuretic peptide, brain natriuretic peptide and β‐myosin heavy chain were simultaneously decreased. Notably, minimal apoptosis and ROS accumulation were identified in AngII‐induced hypertrophic cardiomyocytes. Conversely, the up‐regulation of miR‐200c using specific mimics reversed these effects. Mechanistic investigations demonstrated that the MLCK gene is a direct target of miR‐200c; an increase in miR‐200c levels led to a decrease in the expression of MLCK and its downstream effector, p‐MLC2, while miR‐200c inhibition increased the expression of these proteins. Furthermore, inhibiting MLCK impaired the anti‐hypertrophic effects contributions produced by the knockdown of miR‐200c.

Conclusion

Our studies suggest that miR‐200c may serve as a potential therapeutic target that could delay hypertrophy. We have also uncovered a relationship between miR‐200c and MLCK, identifying MLCK as a direct mediator of miR‐200c.