Overexpression of microRNA-99a Attenuates Cardiac Hypertrophy

MiR-99a-5p up-regulates LDLR and functionally enhances LDL-C uptake via suppressing PCSK9 expression in human hepatocytes

Background

MicroRNAs (miRs/miRNAs) play pivotal roles in modulating cholesterol homeostasis. Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to low-density lipoprotein receptor (LDLR) at the surface of hepatocytes and accelerates its degradation in lysosomes, thereby impairing the clearance of circulating low-density lipoprotein cholesterol (LDL-C) from plasma. Thus, suppressing PCSK9 expression level has become an effective approach for treating hypercholesterolemia. Here, we sought to identify novel miRNAs that inhibit PCSK9 expression.

Methods

By in silico analyses, miR-99a-5p was predicted to bind to human PCSK9 mRNA. Following transfection of miR-99a-5p or anti-miR-99a-5p in human and mouse hepatocytes, qRT-PCR, Western blot, immunofluorescence, ELISA, flow cytometry, LDL-C uptake, and cellular cholesterol measurement were performed.

Results

miR-99a-5p overexpression potently inhibited PCSK9 expression, thereby up-regulating LDLR, functionally enhancing LDL-C uptake and increasing intracellular cholesterol levels in human, but not in mouse, cells. Conversely, anti-miR-99a-5p upregulates PCSK9, leading to a reduction in LDLR, attenuation of LDL-C uptake, and a decrease in the intracellular cholesterol levels of human hepatocytes. Furthermore, miR-99a-5p was shown to bind to the predicted target site "UACGGGU" in the 3'-UTR of human PCSK9 mRNA via a luciferase reporter assay in combination with site-directed mutagenesis.

Conclusion

MiR-99a-5p potently downregulates the expression of PCSK9 by directly interacting with a target site in the human PCSK9 3'-UTR, thereby up-regulating LDLR and functionally enhancing LDL-C uptake in human hepatocytes. MiR-99a-5p could serve as an inhibitor of PCSK9 for treating hypercholesterolemia to inhibit atherosclerosis.

Circulating microRNAs and therapy-associated cardiac events in HER2-positive breast cancer patients: an exploratory analysis from NeoALTTO

PURPOSE

The relevance of cardiotoxicity in the context of HER2-positive breast cancer is likely to increase with increasing patient treatment exposure, number of treatment lines, and prolonged survival. Circulating biomarkers to early identify patients at risk of cardiotoxicity could allow personalized treatment and follow-up measures. The aim of this study is to examine the relationship between circulating microRNAs and adverse cardiac events in HER2-positive breast cancer patients.

METHODS

We based our work on plasma samples from NeoALTTO trial obtained at baseline, after 2 weeks of anti-HER2 therapy, and immediately before surgery. Eleven patients experienced either a symptomatic or asymptomatic cardiac event. Circulating microRNAs were profiled in all patients presenting a cardiac event (case) and in an equal number of matched patients free of reported cardiac events (controls) using microRNA-Ready-to-Use PCR (Human panel I + II). Sensitivity analyses were performed by increasing the number of controls to 1:2 and 1:3. Normalized microRNA expression levels were compared between cases and controls using the non-parametric Kruskal-Wallis test.

RESULTS

Eight circulating microRNAs resulted differentially expressed after 2 weeks of anti-HER2 therapy between patients experiencing or not a cardiac event. Specifically, the expression of miR-125b-5p, miR-409-3p, miR-15a-5p, miR-423-5p, miR-148a-3p, miR-99a-5p, and miR-320b increased in plasma of cases as compared to controls, while the expression of miR-642a-5p decreases. Functional enrichment analysis revealed that all these microRNAs were involved in cardiomyocyte adrenergic signaling pathway.

CONCLUSION

This study provides proof of concept that circulating microRNAs tested soon after treatment start could serve as biomarkers of cardiotoxicity in a very early stage in breast cancer patients receiving anti-HER2 therapy.

Potential Implications of Hyperoside on Oxidative Stress-Induced Human Diseases: A Comprehensive Review

Hyperoside is a flavonol glycoside mainly found in plants of the genera Hypericum and Crataegus, and also detected in many plant species such as Abelmoschus manihot, Ribes nigrum, Rosa rugosa, Agrostis stolonifera, Apocynum venetum and Nelumbo nucifera. This compound exhibits a multitude of biological functions including anti-inflammatory, antidepressant, antioxidative, vascular protective effects and neuroprotective effects, etc. This review summarizes the quantification, original plant, chemical structure and property, structure-activity relationship, pharmacologic effect, pharmacokinetics, toxicity and clinical application of hyperoside, which will be significant for the exploitation for new drug and full utilization of this compound.

Developmental programming: Adipose depot-specific regulation of non-coding RNAs and their relation to coding RNA expression in prenatal testosterone and prenatal bisphenol-A -treated female sheep

Inappropriate developmental exposure to steroids is linked to metabolic disorders. Prenatal testosterone excess or bisphenol A (BPA, an environmental estrogen mimic) leads to insulin resistance and adipocyte disruptions in female lambs. Adipocytes are key regulators of insulin sensitivity. Metabolic tissue-specific differences in insulin sensitivity coupled with adipose depot-specific changes in key mRNAs, were previously observed with prenatal steroid exposure. We hypothesized that depot-specific changes in the non-coding RNA (ncRNA) - regulators of gene expression would account for the direction of changes seen in mRNAs. Non-coding RNA (lncRNA, miRNA, snoRNA, snRNA) from various adipose depots of prenatal testosterone and BPA-treated animals were sequenced. Adipose depot-specific changes in the ncRNA that are consistent with the depot-specific mRNA expression in terms of directionality of changes and functional implications in insulin resistance, adipocyte differentiation and cardiac hypertrophy were found. Importantly, the adipose depot-specific ncRNA changes were model-specific and mutually exclusive, suggestive of different regulatory entry points in this regulation.

TANK Promotes Pressure Overload Induced Cardiac Hypertrophy via Activating AKT Signaling Pathway

Background: TANK (TRAF family member associated NF-κB activator) acts as a member of scaffold proteins participated in the development of multiple diseases. However, its function in process of cardiac hypertrophy is still unknown.

Methods and Results: In this study, we observed an increased expression of TANK in murine hypertrophic hearts after aortic banding, suggesting that TANK may be involved in the pathogenesis of cardiac hypertrophy. We generated cardiac-specific TANK knockout mice, and subsequently subjected to aortic banding for 4–8 weeks. TANK knockout mice showed attenuated cardiac hypertrophy and dysfunction compared to the control group. In contrast, cardiac-specific TANK transgenic mice showed opposite signs. Consistently, in vitro experiments revealed that TANK knockdown decreased the cell size and expression of hypertrophic markers. Mechanistically, AKT signaling was inhibited in TANK knockout mice, but activated in TANK transgenic mice after aortic banding. Blocking AKT signaling with a pharmacological AKT inhibitor alleviated the cardiac hypertrophy and dysfunction in TANK transgenic mice.

Conclusions: Collectively, we identified TANK accelerates the progression of pathological cardiac hypertrophy and is a potential therapeutic target.

Adding a "Notch" to Cardiovascular Disease Therapeutics: A MicroRNA-Based Approach

Dysregulation of the Notch pathway is implicated in the pathophysiology of cardiovascular diseases (CVDs), but, as of today, therapies based on the re-establishing the physiological levels of Notch in the heart and vessels are not available. A possible reason is the context-dependent role of Notch in the cardiovascular system, which would require a finely tuned, cell-specific approach. MicroRNAs (miRNAs) are short functional endogenous, non-coding RNA sequences able to regulate gene expression at post-transcriptional levels influencing most, if not all, biological processes. Dysregulation of miRNAs expression is implicated in the molecular mechanisms underlying many CVDs. Notch is regulated and regulates a large number of miRNAs expressed in the cardiovascular system and, thus, targeting these miRNAs could represent an avenue to be explored to target Notch for CVDs. In this Review, we provide an overview of both established and potential, based on evidence in other pathologies, crosstalks between miRNAs and Notch in cellular processes underlying atherosclerosis, myocardial ischemia, heart failure, calcification of aortic valve, and arrhythmias. We also discuss the potential advantages, as well as the challenges, of using miRNAs for a Notch-based approach for the diagnosis and treatment of the most common CVDs.

The Impact of microRNAs in Renin-Angiotensin-System-Induced Cardiac Remodelling

Current knowledge on the renin-angiotensin system (RAS) indicates its central role in the pathogenesis of cardiovascular remodelling via both hemodynamic alterations and direct growth and the proliferation effects of angiotensin II or aldosterone resulting in the hypertrophy of cardiomyocytes, the proliferation of fibroblasts, and inflammatory immune cell activation. The noncoding regulatory microRNAs has recently emerged as a completely novel approach to the study of the RAS. A growing number of microRNAs serve as mediators and/or regulators of RAS-induced cardiac remodelling by directly targeting RAS enzymes, receptors, signalling molecules, or inhibitors of signalling pathways. Specifically, microRNAs that directly modulate pro-hypertrophic, pro-fibrotic and pro-inflammatory signalling initiated by angiotensin II receptor type 1 (AT1R) stimulation are of particular relevance in mediating the cardiovascular effects of the RAS. The aim of this review is to summarize the current knowledge in the field that is still in the early stage of preclinical investigation with occasionally conflicting reports. Understanding the big picture of microRNAs not only aids in the improved understanding of cardiac response to injury but also leads to better therapeutic strategies utilizing microRNAs as biomarkers, therapeutic agents and pharmacological targets.

Expression Profile of Circulating MicroRNAs in Dogs With Cardiac Hypertrophy: A Pilot Study

This study aimed to identify the expression profile of circulating microRNAs in dogs with eccentric or concentric cardiac hypertrophy. A total of 291 microRNAs in serum samples of five dogs with myxomatous mitral valve degeneration (MMVD) and five dogs with pulmonic stenosis (PS) were compared with those of five healthy dogs using microarray analysis. Results of microarray analysis revealed up-regulation of cfa-miR-130b [fold change (FC) = 2.13, p = 0.014), down-regulation of cfa-miR-375 (FC = 1.51, p = 0.014), cfa-miR-425 (FC = 2.56, p = 0.045), cfa-miR-30d (FC = 3.02, p = 0.047), cfa-miR-151 (FC = 1.89, p = 0.023), cfa-miR-19b (FC = 3.01, p = 0.008), and cfa-let-7g (FC = 2.53, p = 0.015) in MMVD group which showed eccentric cardiac hypertrophy, up-regulation of cfa-miR-346 (FC = 2.74, p = 0.032), down-regulation of cfa-miR-505 (FC = 1.56, p = 0.016) in PS group which showed concentric cardiac hypertrophy, and down-regulation of cfa-miR-30c (FC = 3.45, p = 0.013 in MMVD group; FC = 3.31, p = 0.014 in PS group) and cfa-let-7b (FC = 11.42, p = 0.049 in MMVD group; FC = 5.88, p = 0.01 in PS group) in both MMVD and PS groups. In addition, the unsupervised hierarchical clustering of differentially expressed microRNAs in each group resulted in complete separation of healthy dogs from dogs with heart diseases. Therefore, eleven microRNAs among 291 microRNAs were identified as differentially expressed circulating microRNAs related to MMVD or PS in dogs. This pilot study demonstrates that the microRNAs identified in this study could be possible candidates for novel biomarker or therapeutic target related to cardiac hypertrophy in dogs.

Targeting the renin angiotensin system for the treatment of anxiety and depression

Emotional disorders like anxiety and depression are responsible for considerable morbidity and mortality all over the world. Several antidepressant and anxiolytic medications are available for the treatment of anxiety and depression. However, a significant number of patients either do not respond to these medications or respond inadequately. Hence, there is a need to identify novel targets for the treatment of anxiety and depression. In this review we focus on the renin angiotensin system (RAS) as a potential target for the treatment of these disorders. We review work that has evaluated the effects of various compounds targeting the RAS on anxiety- and depression-like behaviors. Further, we suggest future work that must be carried out to fully exploit the RAS for the treatment of anxiety and depression. The RAS provides an attractive target for both the identification of novel anxiolytic and antidepressant medications and/or for enhancing the efficacy of currently available medications used for the treatment of anxiety and depression.

Mybl2 rejuvenates heart explant-derived cells from aged donors after myocardial infarction

While cell therapy is emerging as a promising option for patients with ischemic cardiomyopathy (ICM), the influence of advanced donor age and a history of ischemic injury on the reparative performance of these cells are not well defined. As such, intrinsic changes that result from advanced donor age and ischemia are explored in hopes of identifying a molecular candidate capable of restoring the lost reparative potency of heart explant‐derived cells (EDCs) used in cell therapy. EDCs were cultured from myocardial biopsies obtained from young or old mice 4 weeks after randomization to experimental myocardial infarction or no intervention. Advanced donor age reduces cell yield while increasing cell senescence and the secretion of senescence‐associated cytokines. A history of ischemic injury magnifies these effects as cells are more senescent and have lower antioxidant reserves. Consistent with these effects, intramyocardial injection of EDCs from aged ischemic donors provided less cell‐mediated cardiac repair. A transcriptome comparison of ICM EDCs shows aging modifies many of the pathways responsible for effective cell cycle control and DNA damage/repair. Over‐expression of the barely explored antisenescent transcription factor, Mybl2, in EDCs from aged ICM donors reduces cell senescence while conferring salutary effects on antioxidant activity and paracrine production. In vivo, we observed an increase in cell retention and vasculogenesis after treatment with Mybl2‐over‐expressing EDCs which improved heart function in infarcted recipient hearts. In conclusion, Mybl2 over‐expression rejuvenates senescent EDCs sourced from aged ICM donors to confer cell‐mediated effects comparable to cells from young nonischemic donors.

Analysis of extracellular vesicle miRNA profiles in heart failure

Extracellular vesicles (EVs) have recently emerged as an important carrier for various genetic materials including microRNAs (miRs). Growing evidences suggested that several miRs transported by EVs were particularly involved in modulating cardiac function. However, it has remained unclear what miRs are enriched in EVs and play an important role in the pathological condition. Therefore, we established the miR expression profiles in EVs from murine normal and failing hearts and consecutively identified substantially altered miRs. In addition, we have performed bioinformatics approach to predict potential cardiac outcomes through the identification of miR targets. Conclusively, we observed approximately 63% of predicted targets were validated with previous reports. Notably, the predicted targets by this approach were often involved in both beneficial and malicious signalling pathways, which may reflect heterogeneous cellular origins of EVs in tissues. Lastly, there has been an active debate on U6 whether it is a proper control. Through further analysis of EV miR profiles, miR‐676 was identified as a superior reference control due to its consistent and abundant expressions. In summary, our results contribute to identifying specific EV miRs for the potential therapeutic targets in heart failure and suggest that miR‐676 as a new reference control for the EV miR studies.

Up-regulation of SNHG16 induced by CTCF accelerates cardiac hypertrophy by targeting miR-182-5p/IGF1 axis

Long non-coding RNA (lncRNA) SNHG16 has been reported to be significant regulators in multiple cancers. However, never has the relationship between it and cardiac hypertrophy been studied until now. In this study, angiotensin II (Ang II)-treated cardiomyocytes isolated from neonatal mice were used as a model of cardiac hypertrophy in vitro. Real-time quantitative polymerase chain reaction was performed to measure the expression of SNHG16, miR-182-5p, and insulin-like growth factor 1 (IGF1). The relationship between SNHG16 and its downstream genes were corroborated by RNA pull-down and luciferase reporter experiments. Western blot was conducted to detect the expression of markers of hypertrophy. The results disclosed that SNHG16 expression was in a high level in the cardiac hypertrophic model. Down-regulation of SNHG16 could decline the expression of hypertrophic markers and reduce cell surface area induced by Ang II. Moreover, SNHG16 was discovered to be activated by transcription factor CCCTC-binding factor. In addition, SNHG16 could enlarge cell surface area and increase the expression of hypertrophic markers by inhibiting miR-182-5p expression in Ang II-treated cardiomyocytes. Finally, overexpression of IGF1 could rescue the effects of silenced SNHG16 on cardiac hypertrophy cells. In brief, our study illustrated that silenced SNHG16 repressed Ang II-imposed cardiac hypertrophy via targeting miR-182-5p/IGF1 axis.

MicroRNAs in the Vitreous Humor of Patients with Retinal Detachment and a Different Grading of Proliferative Vitreoretinopathy: A Pilot Study

Purpose

Although the expression of microRNAs (miRNAs) in retinal pigment epithelial (RPE) cells undergoing epithelial-mesenchymal transition (EMT) is involved in the pathogenesis of proliferative vitreoretinopathy (PVR), its expression in the vitreous of patients with primary retinal detachment (RD) and different PVR grading has not yet been investigated. We assessed the expression of miRNAs in the vitreous humor (VH) of patients diagnosed with RD and different grading of PVR.

Methods

The VH was extracted from the core of the vitreous chamber in patients who had undergone standard vitrectomy for primary RD. RNA was extracted and TaqMan Low-Density Arrays (TLDAs) were used for miRNA profiling that was performed by single TaqMan assays. A gene ontology (GO) analysis was performed on the differentially expressed miRNAs.

Results

A total of 15 eyes with RD, 3 eyes for each grade of PVR (A, B, C, and D) and 3 from unaffected individuals, were enrolled in this prospective comparative study. Twenty miRNAs were altered in the comparison among pathological groups. Interestingly, the expression of miR-143-3p, miR-224-5p, miR-361-5p, miR-452-5p, miR-486-3p, and miR-891a-5p increased with the worsening of PVR grading. We also identified 34 miRNAs showing differential expression in PVR compared to control vitreous samples. GO analysis showed that the deregulated miRNAs participate in processes previously associated with PVR pathogenesis.

Conclusions

The present pilot study suggested that dysregulated vitreal miRNAs may be considered as a biomarker of PVR and associated with the PVR-related complications in patients with RD.

Translational Relevance

The correlation between vitreal miRNAs and the pathological phenotypes are essential to identify the novel miRNA-based mechanisms underlying the PVR disease that would improve the diagnosis and treatment of the condition.

YQWY decoction reverses cardiac hypertrophy induced by TAC through inhibiting GATA4 phosphorylation and MAPKs

To investigate the effect of Yiqi Wenyang (YQWY) decoction on reversing cardiac hypertrophy induced by the transverse aortic constriction (TAC). Wistar rats aged 7-8 weeks were subjected to TAC surgery and then randomly divided into 4 groups (n = 5/group): Sham group, TAC group, low-dose group and high dose group. After 16-week intragastric administration of YQWY decoction, the effect of YQWY decoction on alleviating cardiomyocyte hypertrophy was examined by transthoracic echocardiography (TTE), hematoxylin/eosin (HE), wheat germ agglutinin (WGA) staining, enzyme linked immunosorbent assay (ELISA), Western blot (WB), immunohistochemistry (IHC) and immunofluorescence (IF), respectively. The results showed significant differences in left ventricle volume-diastole/systole (LV Vol d/s), N-terminal pro-B-type brain natriuretic peptide (NT-proBNP) (P < 0.01), Ejection Fraction (EF), LV mass and fractional shortening (FS) (P < 0.05) between YQWY-treated group and TAC group. HE and WGA staining showed that treatment with YQWY decoction dramatically prevented TAC-induced cardiomycyte hypertrophy. Moreover, the results of WB, IHC and IF indicated that administration of YQWY could suppress the expressions of cardiac hypertrophic markers, which included the atrial natriuretic peptide (ANP), BNP and myosin heavy chain 7 (MYH7) (P < 0.05) and inhibit phosphorylation of GATA binding protein 4 (P-GATA4) (P < 0.05), phosphorylation of extracellular signal-regulated kinase (P-ERK) (P < 0.05), phosphorylation of P38 mitogen activated protein kinase (P-P38) (P < 0.05) and phosphorylation of c-Jun N-terminal kinase (P-JNK) (P < 0.05). Thus, we concluded that YQWY decoction suppressed cardiomyocyte hypertrophy and reversed the impaired heart function, and the curative effects of YQWY decoction were associated with the decreased phosphorylation of GATA4 and mitogen activated protein kinases (MAPKs), as well as the reduced expression of the downstream targets of GATA4, including ANP, BNP, and MYH7.

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

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

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

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

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

Mature miR-99a Upregulation in the Amniotic Fluid Samples from Female Fetus Down Syndrome Pregnancies: A Pilot Study

Background and Objective: Although Down syndrome is the most frequent aneuploidy, its pathogenic molecular mechanisms are not yet fully understood. The aim of our study is to quantify-by qRT-PCR-the expression levels of both the mature forms and the pri-miRNAs of the microRNAs resident on chromosome 21 (miR(21)) in the amniotic fluid samples from Down syndrome singleton pregnancies and to estimate the impact of the differentially expressed microRNAs on Down syndrome fetal heart and amniocytes transcriptomes. Materials and methods: We collected amniotic fluid samples harvested by trained obstetricians as part of the second trimester screening/diagnostic procedure for aneuploidies to assess the trisomy 21 status by QF-PCR and karyotyping. Next, we evaluated-by Taqman qRT-PCR-the expression levels of both the mature forms and the pri-miRNA precursors of the microRNAs resident on chromosome 21 in amniotic fluid samples from singleton Down syndrome and euploid pregnancies. Further, we combined miRWalk 3.0 microRNA target prediction with GEO DataSets analysis to estimate the impact of hsa-miR-99a abnormal expression on Down syndrome heart and amniocytes transcriptome. Results: We found a statistically significant up-regulation of the mature form of miR-99a, but not pri-miR-99a, in the amniotic fluid samples from Down syndrome pregnancies with female fetuses. GATHER functional enrichment analysis of miRWalk3.0-predicted targets from Down syndrome amniocytes and fetal hearts transcriptome GEODataSets outlined both focal adhesion and cytokine-cytokine receptor interaction signaling as novel signaling pathways impacted by miR-99a and associated with cardiac defects in female Down syndrome patients. Conclusions: The significant overexpression of miR-99a, but not pri-miR-99a, points towards an alteration of the post-transcriptional mechanisms of hsa-miR-99a maturation and/or stability in the female trisomic milieu, with a potential impact on signaling pathways important for proper development of the heart.

Physiologic expansion of human heart-derived cells enhances therapeutic repair of injured myocardium

Background

Serum-free xenogen-free defined media and continuous controlled physiological cell culture conditions have been developed for stem cell therapeutics, but the effect of these conditions on the relative potency of the cell product is unknown. As such, we conducted a head-to-head comparison of cell culture conditions on human heart explant-derived cells using established in vitro measures of cell potency and in vivo functional repair.

Methods

Heart explant-derived cells cultured from human atrial or ventricular biopsies within a serum-free xenogen-free media and a continuous physiological culture environment were compared to cells cultured under traditional (high serum) cell culture conditions in a standard clean room facility.

Results

Transitioning from traditional high serum cell culture conditions to serum-free xenogen-free conditions had no effect on cell culture yields but provided a smaller, more homogenous, cell product with only minor antigenic changes. Culture within continuous physiologic conditions markedly boosted cell proliferation while increasing the expression of stem cell-related antigens and ability of cells to stimulate angiogenesis. Intramyocardial injection of physiologic cultured cells into immunodeficient mice 1 week after coronary ligation translated into improved cardiac function and reduced scar burden which was attributable to increased production of pro-healing cytokines, extracellular vesicles, and microRNAs.

Conclusions

Continuous physiological cell culture increased cell growth, paracrine output, and treatment outcomes to provide the greatest functional benefit after experimental myocardial infarction.

New Insights Into the Role of mTOR Signaling in the Cardiovascular System

The mTOR (mechanistic target of rapamycin) is a master regulator of several crucial cellular processes, including protein synthesis, cellular growth, proliferation, autophagy, lysosomal function, and cell metabolism. mTOR interacts with specific adaptor proteins to form 2 multiprotein complexes, called mTORC1 (mTOR complex 1) and mTORC2 (mTOR complex 2). In the cardiovascular system, the mTOR pathway regulates both physiological and pathological processes in the heart. It is needed for embryonic cardiovascular development and for maintaining cardiac homeostasis in postnatal life. Studies involving mTOR loss-of-function models revealed that mTORC1 activation is indispensable for the development of adaptive cardiac hypertrophy in response to mechanical overload. mTORC2 is also required for normal cardiac physiology and ensures cardiomyocyte survival in response to pressure overload. However, partial genetic or pharmacological inhibition of mTORC1 reduces cardiac remodeling and heart failure in response to pressure overload and chronic myocardial infarction. In addition, mTORC1 blockade reduces cardiac derangements induced by genetic and metabolic disorders and has been reported to extend life span in mice. These studies suggest that pharmacological targeting of mTOR may represent a therapeutic strategy to confer cardioprotection, although clinical evidence in support of this notion is still scarce. This review summarizes and discusses the new evidence on the pathophysiological role of mTOR signaling in the cardiovascular system.

Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology

The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT₁R) is believed to mediate most functions of ANG II in the system. AT₁R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT₁R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT₁R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.

Anesthetic-induced Myocardial Conditioning: Molecular Fundamentals and Scope

BACKGROUND

The pre- and post-conditioning effects of halogenated anesthetics make them most suitable for cardiac surgery. Several studies have demonstrated that the mechanism of drug-induced myocardial conditioning is enzyme-mediated via messenger RNA and miRNA regulation. The objective of this study was to investigate the role that miRNAs play in the cardioprotective effect of halogenated anesthetics. For such purpose, we reviewed the literature to determine the expression profile of miRNAs in ischemic conditioning and in the complications prevented by these phenomena.

METHODS

A review was conducted of more than 100 studies to identify miRNAs involved in anesthetic-induced myocardial conditioning. Our objective was to determine the miRNAs that play a relevant role in ischemic disease, heart failure and arrhythmogenesis, which expression is modulated by the perioperative administration of halogenated anesthetics. So far, no studies have been performed to assess the role of miRNAs in anesthetic-induced myocardial conditioning. The potential of miRNAs as biomarkers and miRNAs-based therapies involving the synthesis, inhibition or stimulation of miRNAs are a promising avenue for future research in the field of cardiology.

RESULTS

Each of the cardioprotective effects of myocardial conditioning is related to the expression of several (not a single) miRNAs. The cumulative evidence on the role of miRNAs in heart disease and myocardial conditioning opens new therapeutic and diagnostic opportunities.

CONCLUSION

Halogenated anesthetics regulate the expression of miRNAs involved in heart conditions. Further research is needed to determine the expression profile of miRNAs after the administration of halogenated drugs. The results of these studies would contribute to the development of new hypnotics for cardiac surgery patients.

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.

MicroRNA-99a mimics inhibit M1 macrophage phenotype and adipose tissue inflammation by targeting TNFα

In human adipose tissue and obesity, miR-99a expression is negatively correlated with inflammation. Therefore, the present study investigated the role of miR-99a in macrophage phenotype activation and adipose tissue inflammation. M2 BMDMs showed a significant increase in miR-99a expression when compared to the M0 and M1 phenotypes. Phenotype-switching experiments established an association between upregulated miR-99a expression and the M2 phenotype. Overexpression of miR-99a prevented M1 phenotype activation and attenuated bactericidal activity. Likewise, knockdown of miR-99a abolished M2 phenotype activation. By means of in silico target prediction tools and a luciferase reporter assay, TNFα was identified as a direct target of miR-99a. Knockdown of TNFα recapitulated the effect of miR-99a overexpression in M1 BMDMs. In a db/db mice model, miR-99a expression was reduced in eWAT and F4/80⁺ ATMs. Systemic overexpression of miR-99a in db/db mice attenuated adipocyte hypertrophy with increased CD301 and reduced CD86 immunostaining. Flow cytometry analysis also showed an increased M2 and a reduced M1 macrophage population. Mimics of miR-99a also improved the diabetic dyslipidemia and insulin signaling in eWAT and liver, with an attenuated expression of gluconeogenesis and cholesterol metabolism genes in the liver. Furthermore, adoptive transfer of miR-99a-overexpressing macrophages in the db/db mice recapitulated in vivo miR-99a mimic effects with increased M2 and reduced M1 macrophage populations and improved systemic glucose, insulin sensitivity, and insulin signaling in the eWAT and liver. The present study demonstrates that miR-99a mimics can regulate macrophage M1 phenotype activation by targeting TNFα. miR-99a therapeutics in diabetic mice reduces the adipose tissue inflammation and improves insulin sensitivity.

The long noncoding RNA THRIL knockdown protects hypoxia-induced injuries of H9C2 cells through regulating miR-99a

BACKGROUND

Myocardial infarction (MI) is a leading cause of disease with high morbidity and mortality worldwide. Recent studies have revealed that long non-coding RNAs (lncRNAs) are involved in heart disease pathogenesis. This study aimed to investigate the effect and the molecular basis of THRIL on hypoxia-injured H9C2 cells.

METHODS

THRIL, miR-99a and Brahma-related gene 1 (Brg1) expressions in H9C2 cells were altered by transient transfections. The cells were subjected to hypoxia for 4 h, and then the levels of THRIL, miR-99a and Brg1 were investigated. Cell viability, migration and invasion, and apoptotic cells were respectively measured by trypan blue exclusion assay, transwell migration assay and flow cytometry assay. Dual luciferase reporter assay was conducted to verify the interaction between miR-99a and THRIL. Furthermore, levels of apoptosis-, PI3K/AKT and mTOR pathways-related factors were measured by western blotting.

RESULTS

Hypoxia induced an increase of THRIL but a reduction of miR-99a and Brg1. THRIL inhibition significantly attenuated hypoxia-induced cell injuries, as increased cell viability, migration and invasion, and decreased cell apoptosis. THRIL negatively regulated miR-99a expression through sponging with miR-99a binding site, and miR-99a inhibition abolished the protective effects of THRIL knockdown against hypoxia-induced injury in H9C2 cells. Furthermore, miR-99a positively regulated the expression of Brg1. Brg1 inhibition promoted hypoxia-induced cell injuries, while Brg1 overexpression alleviated hypoxia-induced cell injuries. Moreover, Brg1 overexpression activated PI3K/AKT and mTOR pathways.

CONCLUSIONS

This study demonstrated that THRIL inhibition represented a protective effect against hypoxia-induced injuries in H9C2 cells by up-regulating miR-99a expression.

MicroRNA miR-301a is a novel cardiac regulator of Cofilin-2

Calsarcin-1 deficient mice develop dilated cardiomyopathy (DCM) phenotype in pure C57BL/6 genetic background (Cs1-ko) despite severe contractile dysfunction and robust activation of fetal gene program. Here we performed a microRNA microarray to identify the molecular causes of this cardiac phenotype that revealed the dysregulation of several microRNAs including miR-301a, which was highly downregulated in Cs1-ko mice compared to the wild-type littermates. Cofilin-2 (Cfl2) was identified as one of the potential targets of miR-301a using prediction databases, which we validated by luciferase assay and mutation of predicted binding sites. Furthermore, expression of miR-301a contrastingly regulated Cfl2 expression levels in neonatal rat ventricular cardiomyocytes (NRVCM). Along these lines, Cfl2 was significantly upregulated in Cs1-ko mice, indicating the physiological association between miR-301a and Cfl2 in vivo. Mechanistically, we found that Cfl2 activated serum response factor response element (SRF-RE) driven luciferase activity in neonatal rat cardiomyocytes and in C2C12 cells. Similarly, knockdown of miR301a activated, whereas, its overexpression inhibited the SRF-RE driven luciferase activity, further strengthening physiological interaction between miR-301a and Cfl2. Interestingly, the expression of SRF and its target genes was strikingly increased in Cs1-ko suggesting a possible in vivo correlation between expression levels of Cfl2/miR-301a and SRF activation, which needs to be independently validated. In summary, our data demonstrates that miR-301a regulates Cofilin-2 in vitro in NRVCM, and in vivo in Cs1-ko mice. Our findings provide an additional and important layer of Cfl2 regulation, which we believe has an extended role in cardiac signal transduction and dilated cardiomyopathy presumably due to the reported involvement of Cfl2 in these mechanisms.

miRNAs as potential therapeutic targets and diagnostic biomarkers for cardiovascular disease with a particular focus on WO2010091204

INTRODUCTION

A number of miRNAs have been reported to be critically involved in the regulation of cardiovascular disease (CVDs). Therefore, the development of potent analogues/inhibitors for miRNAs have thus become a key focus in the present drug discovery. In this review, we discuss the basic research and clinical use of miRNAs as the early diagnosis and therapeutic targets for CVD. We have also focused on the efficiency of therapeutically targeting miR-499, which is considered as one of the most promising molecules for treating CVDs. Areas covered: In this review, we have discussed the patents and patent applications related to miRNAs detected in CVD patients published in recent years. This review also covers the expression pattern of miR-499, as well as it highlights functions of its inhibitors in CVD. We used Google and Pubmed search engines to find relevant patents. Expert opinion: Although a massive number of miRNAs are patented as CVD biomarkers, further work is absolutely required to evaluate the reliable diagnostic values and therapeutic potential of these candidates. Overall, targeting miRNAs is definitely a promising strategy to be investigated for diagnosis and treatment of CVDs in future, however, the delivery system and off-targets effects are still a difficult challenge need to be elucidated.

[Use of microRNAs in heart failure management]

Heart failure (HF) is a high impact disease that affects all human populations, demanding the development of new strategies and methods to manage this pathology. That's why microRNAs, small noncoding RNAs that regulate gene expression, appear as an important option in the diagnosis, prognosis and treatment of this disease. MiRNAs seems to have a future on HF handling, because can be isolated from body fluids such as blood, and changes in its levels can be associated with the presence, stage and specific disease features, which makes them an interesting option as biomarkers. Also, due to the important role of these molecules on regulation of gene expression and cell homeostasis, it has been explored its potential use as a therapeutic method to prevent or treat HF. That is why this review seeks to show the importance of biomedical research involving the use of miRNAs as a method to approach the HF, showing the impact of disease in the world, aspects of miRNAs biology, and their use as biomarkers and as important therapeutic targets.

MicroRNA-99a inhibits insulin-induced proliferation, migration, dedifferentiation, and rapamycin resistance of vascular smooth muscle cells by inhibiting insulin-like growth factor-1 receptor and mammalian target of rapamycin

Patients with type 2 diabetes mellitus (T2DM) are characterized by insulin resistance and are subsequently at high risk for atherosclerosis. Hyperinsulinemia has been associated with proliferation, migration, and dedifferentiation of vascular smooth muscle cells (VSMCs) during the pathogenesis of atherosclerosis. Moreover, insulin-like growth factor-1 receptor (IGF-1R) and mammalian target of rapamycin (mTOR) have been demonstrated to be the underlying signaling pathways. Recently, microRNA-99a (miR-99a) has been suggested to regulate the phenotypic changes of VSMCs in cancer cells. However, whether it is involved in insulin-induced changes of VSCMs has not been determined. In this study, we found that insulin induced proliferation, migration, and dedifferentiation of mouse VSMCs in a dose-dependent manner. Furthermore, the stimulating effects of high-dose insulin on proliferation, migration, and dedifferentiation of mouse VSMCs were found to be associated with the attenuation of the inhibitory effects of miR-99a on IGF-1R and mTOR signaling activities. Finally, we found that the inducing effect of high-dose insulin on proliferation, migration, and dedifferentiation of VSMCs was partially inhibited by an active mimic of miR-99a. Taken together, these results suggest that miR-99a plays a key regulatory role in the pathogenesis of insulin-induced proliferation, migration, and phenotype conversion of VSMCs at least partly via inhibition of IGF-1R and mTOR signaling. Our results provide evidence that miR-99a may be a novel target for the treatment of hyperinsulinemia-induced atherosclerosis.

What people with Down Syndrome can teach us about cardiopulmonary disease

Down syndrome is the most common chromosomal abnormality among live-born infants. Through full or partial trisomy of chromosome 21, Down syndrome is associated with cognitive impairment, congenital malformations (particularly cardiovascular) and dysmorphic features. Immune disturbances in Down syndrome account for an enormous disease burden ranging from quality-of-life issues (autoimmune alopecia) to more serious health issues (autoimmune thyroiditis) and life-threatening issues (leukaemia, respiratory tract infections and pulmonary hypertension). Cardiovascular and pulmonary diseases account for ∼75% of the mortality seen in persons with Down syndrome. This review summarises the cardiovascular, respiratory and immune challenges faced by individuals with Down syndrome, and the genetic underpinnings of their pathobiology. We strongly advocate increased comparative studies of cardiopulmonary disease in persons with and without Down syndrome, as we believe these will lead to new strategies to prevent and treat diseases affecting millions of people worldwide.

Nogo-C regulates cardiomyocyte apoptosis during mouse myocardial infarction

Myocardial infarction is caused by insufficient coronary blood supply, which leads to myocardial damage and eventually the heart failure. Molecular mechanisms associated with the loss of cardiomyocytes during myocardial infarction (MI) and ischemia-related cardiac diseases are not yet fully understood. Nogo-C is an endoplasmic reticulum protein ubiquitously expressed in tissues including in the heart, however, the cardiac function of Nogo-C is still unknown. In the present study, we found that Nogo-C was upregulated in mouse hearts after MI, and hypoxic treatments also increased Nogo-C protein level in cardiomyocytes. Adenovirus mediated overexpression of Nogo-C led to cardiomyocyte apoptosis, whereas knockdown of Nogo-c by shRNA protected cardiomyocytes from hypoxia-induced cell apoptosis. Importantly, Nogo-C knockout mice displayed improved cardiac function, smaller infarct area, and less apoptotic cells after MI. Moreover, we found that miR-182 negatively regulated Nogo-C expression and was downregulated during MI, expressing miR-182 in cardiomyocytes protected hypoxia- and Nogo-C-mediated cell apoptosis. Our results indicate that increased cardiac Nogo-C expression is both sufficient and necessary for ischemia-induced cardiomyocyte apoptosis and cardiac dysfunction, suggesting that deregulation of Nogo-C by miRNA may be a potential therapeutic target for ischemia-related heart diseases.