The microRNA-132/212 family fine-tunes multiple targets in Angiotensin II signalling in cardiac fibroblasts

Lung cancer-derived exosomal miR-132-3p contributed to interstitial lung disease development

PURPOSE

Interstitial lung diseases (ILDs) have high morbidity and mortality and poor prognosis. The significance of microRNAs (miRNAs) was highlighted in ILDs development. Currently, we attempted to confirm the functions of lung cancer-derived exosomal miR-132-3p and reveal the underlying mechanism.

METHOD

Characteristics of exosomes were verified by transmission electron microscope (TEM), nanoparticle tracking analysis, and Western blot assay. Exosome uptake for the normal human lung fibroblasts (NHLF) was assessed using a PKH67 staining assay. MTT and colony formation assays were applied to examine the proliferation abilities of NHLF. The interaction between miR-132-3p and sprouty1 (SPRY1) was confirmed by a luciferase reporter assay.

RESULTS

Lung cancer-derived exosomes promoted normal human lung fibroblast activation. Exosome inhibitor GW4869 reversed the effects of Exo on NHLF. Subsequently, miR-132-3p in lung cancer-derived exosomes activated the normal human lung fibroblast and promoted interstitial lung disease development ex vivo. Next, SPRY1 was verified to be the binding protein of miR-132-3p, and sh-SPRY1 abrogated the effects of the miR-132-3p inhibitor on NHLF.

CONCLUSION

Exosomal miR-132-3p from A549 cells accelerated the development of interstitial lung disease through binding to SPRY1, which might serve as an important target for ILDs.

Cardiac Remodeling After Myocardial Infarction: Functional Contribution of microRNAs to Inflammation and Fibrosis

After an ischemic injury, the heart undergoes a complex process of structural and functional remodeling that involves several steps, including inflammatory and fibrotic responses. In this review, we are focusing on the contribution of microRNAs in the regulation of inflammation and fibrosis after myocardial infarction. We summarize the most updated studies exploring the interactions between microRNAs and key regulators of inflammation and fibroblast activation and we discuss the recent discoveries, including clinical applications, in these rapidly advancing fields.

Advances in miR-132-Based Biomarker and Therapeutic Potential in the Cardiovascular System

Atherosclerotic cardiovascular disease and subsequent heart failure threaten global health and impose a huge economic burden on society. MicroRNA-132 (miR-132), a regulatory RNA ubiquitously expressed in the cardiovascular system, is up-or down-regulated in the plasma under various cardiac conditions and may serve as a potential diagnostic or prognostic biomarker. More importantly, miR-132 in the myocardium has been demonstrated to be a master regulator in many pathological processes of ischemic or nonischemic heart failure in the past decade, such as myocardial hypertrophy, fibrosis, apoptosis, angiogenesis, calcium handling, neuroendocrine activation, and oxidative stress, through downregulating target mRNA expression. Preclinical and clinical phase 1b studies have suggested antisense oligonucleotide targeting miR-132 may be a potential therapeutic approach for ischemic or nonischemic heart failure in the future. This review aims to summarize recent advances in the physiological and pathological functions of miR-132 and its possible diagnostic and therapeutic potential in cardiovascular disease.

The emerging role of miRNA-132/212 cluster in neurologic and cardiovascular diseases: Neuroprotective role in cells with prolonged longevity

miRNA-132/212 are small regulators of gene expression with a function that fulfills a vital function in diverse biological processes including neuroprotection of cells with prolonged longevity in neurons and the cardiovascular system. In neurons, miRNA-132 appears to be essential for controlling differentiation, development, and neural functioning. Indeed, it also universally promotes axon evolution, nervous migration, plasticity as well, it is suggested to be neuroprotective against neurodegenerative diseases. Moreover, miRNA-132/212 disorder leads to neural developmental perturbation, and the development of degenerative disorders covering Alzheimer's, Parkinson's, and epilepsy's along with psychiatric perturbations including schizophrenia. Furthermore, the cellular mechanisms of the miRNA-132/212 have additionally been explored in cardiovascular diseases models. Also, the miRNA-132/212 family modulates cardiac hypertrophy and autophagy in cardiomyocytes. The protective and effective clinical promise of miRNA-132/212 in these systems is discussed in this review. To sum up, the current progress in innovative miRNA-based therapies for human pathologies seems of extreme concern and reveals promising novel therapeutic strategies.

GDF15 and Cardiac Cells: Current Concepts and New Insights

Growth and differentiation factor 15 (GDF15) belongs to the transforming growth factor-β (TGF-β) superfamily of proteins. Glial-derived neurotrophic factor (GDNF) family receptor α-like (GFRAL) is an endogenous receptor for GDF15 detected selectively in the brain. GDF15 is not normally expressed in the tissue but is prominently induced by “injury”. Serum levels of GDF15 are also increased by aging and in response to cellular stress and mitochondrial dysfunction. It acts as an inflammatory marker and plays a role in the pathogenesis of cardiovascular diseases, metabolic disorders, and neurodegenerative processes. Identified as a new heart-derived endocrine hormone that regulates body growth, GDF15 has a local cardioprotective role, presumably due to its autocrine/paracrine properties: antioxidative, anti-inflammatory, antiapoptotic. GDF15 expression is highly induced in cardiomyocytes after ischemia/reperfusion and in the heart within hours after myocardial infarction (MI). Recent studies show associations between GDF15, inflammation, and cardiac fibrosis during heart failure and MI. However, the reason for this increase in GDF15 production has not been clearly identified. Experimental and clinical studies support the potential use of GDF15 as a novel therapeutic target (1) by modulating metabolic activity and (2) promoting an adaptive angiogenesis and cardiac regenerative process during cardiovascular diseases. In this review, we comment on new aspects of the biology of GDF15 as a cardiac hormone and show that GDF15 may be a predictive biomarker of adverse cardiac events.

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.

MicroRNA-132 regulates salt-dependent steady-state renin levels in mice

The body's salt and fluid balance is regulated by the renin-angiotensin-aldosterone system. Generation of prostaglandin-E2 (PGE2) in a cyclo-oxygenase-2 (COX-2)-dependent manner in the macula densa, the salt-sensing cells of the kidney, plays a dominant role in renin regulation. Here we show that miR-132 directly targets Cox-2 and affects subsequent PGE2 and renin levels. MiR-132 is induced and reduced by low- and high salt treatment, respectively, in a p38- and ERK1/2-independent and CREB- and salt inducible kinase-dependent manner. Silencing of miR-132 in mice increases macula densa COX-2 expression and elevates PGE2 and renin levels, which are abrogated by the selective COX-2-inhibitor Celecoxib. Furthermore, a low or high salt diet induces and reduces macula densa miR-132 expression, while low salt diet combined with silencing miR-132 further increases renin levels. Taken together, we demonstrate a posttranscriptional regulatory role for salt-dependent miR-132 in fine-tuning the steady-state levels of renin.

Retracted: Upregulated microRNA-132 rescues cardiac fibrosis and restores cardiocyte proliferation in dilated cardiomyopathy through the phosphatase and tensin homolog-mediated PI3K/Akt signal transduction pathway

Cardiac fibrosis is known to be present in dilated cardiomyopathy (DCM) and it predicts the occurrence of sudden death and congestive heart failure. The aim of our study is to investigate the expression of microRNA-132 (miR-132) and its effect on cardiocyte proliferation, apoptosis, and cardiac fibrosis by binding to phosphatase and tensin homolog (PTEN) through the phosphateidylinositol 3-kinase (PI3K)/protein kinase (Akt) signal transduction pathway in DCM rats. DCM rat models induced by doxorubicin were established and confirmed by an ultrasonic cardiogram. Epithelial cells were treated with inhibitors, activators, and small interfering RNAs to identify the mechanisms by which miR-132 controls cardiocyte activity and cardiac fibrosis. Angiotensin II (Ang II) and aldosterone (ALD) expressions were detected by an enzyme-linked immunosorbent assay. The relationship between PTEN and miR-132 was verified by a dual-luciferase reporter assay. Cell proliferation and apoptosis were tested by the MTT assay and flow cytometry. PTEN was determined to be the target gene of miR-132. Rat models of DCM exhibited a lower level of miR-132, PI3K, Akt, B-cell lymphoma 2, collagen I, and collagen III, but a higher level of PTEN, Bcl-2-associated X protein, and proliferating cell nuclear antigen as well as inflammatory response (Ang II and ALD), accompanied by declined cardiocyte proliferation and elevated apoptosis and cardiac fibrosis. Upregulated miR-132 or silenced PTEN activated the PI3K/Akt pathway, thus facilitating cardiocyte proliferation and repressing cardiocyte apoptosis and cardiac fibrosis, as well as inflammatory responses. Downregulated miR-132 reversed this tendency. These findings indicate that miR-132 activates the PI3K/Akt pathway by inhibiting PTEN expression, thus facilitating cardiocyte proliferation and inhibiting apoptosis and cardiac fibrosis in DCM rats.

MicroRNA-212 promotes the recovery function and vascular regeneration of endothelial progenitor cells in mice with ischemic stroke through inactivation of the notch signaling pathway via downregulating MMP9 expression

Ischemic stroke is a refractory disease caused by cerebral ischemic injury, which results in brain dysfunction. This study intends to investigate the effects of microRNA-212 (miR-212) on the recovery function and vascular regeneration of endothelial progenitor cells (EPCs) by inactivation of the Notch signaling pathway by binding to matrix metallopeptidase 9 (MMP9) in mice with ischemic stroke. According to the results of database retrieval systems and data analysis, MMP9 was predicted as a gene related to ischemic stroke and miR-212 is a potential regulating mRNA of MMP9. All 72 healthy adult C57BL6 mice were selected for middle cerebral artery occlusion (MCAO) establishment. Cerebral infarction was observed under triphenyltetrazolium chloride staining. A series of inhibitors, activators, and siRNAs were introduced to the verified regulatory functions for miR-212 governing MMP9 in ischemic stroke. Cell proliferation was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and tube-forming ability by tubule formation test. Reverse transcription quantitative polymerase chain reaction and Western blot analysis were used to detect the expressions of miR-212, MMP9, Hes-1, and Notch-1. The corresponding results demonstrated that the area of cerebral infarction and the number of neuronal necrosis increased in the MCAO group in contrast to the sham group. Meanwhile, upregulation of miR-212 or downregulation of MMP9 decreases the expressions of MMP9, Hes-1 Notch-1, increases cell proliferation and tube-forming ability and improves the pathological conditions of EPCs. Our study suggests that miR-212 promotes recovery function and vascular regeneration of EPCs through negative regulation of the Notch signaling pathway via downregulating expression of MMP9, thus provides a clinical theoretical basis for ischemic stroke therapy.

Protective Action of Diazoxide on Isoproterenol-Induced Hypertrophy Is Mediated by Reduction in MicroRNA-132 Expression

INTRODUCTION AND METHODS

The effects of diazoxide on cardiac hypertrophy and miR-132 expression were characterized in adult rats and in cardiomyocytes. Diazoxide effects on reactive oxygen species (ROS) production and on the cAMP-response element binding (CREB) transcription factor's abundance in cardiomyocytes were also analyzed. ROS measurements used a fluorescent dye. Western blot analysis and quantitative Reverse Transcription Polymerase Chain Reaction were used to measure phosphorylated form of CREB (pCREB) abundance and miR-132 expression, respectively.

RESULTS

Isoproterenol (ISO) induced cardiac hypertrophy, an effect that was mitigated by diazoxide. The rate of ROS production, CREB phosphorylation, and miR-132 expression increased after the addition of ISO. H2O2 increased pCREB abundance and miR-132 expression; upregulation of miR-132 was blocked by the specific inhibitor of CREB transcription, 666-15. Consistent with a role of ROS on miR-132 expression, diazoxide prevented the increase in ROS production, miR-132 expression, and pCREB abundance produced by ISO. Phosphorylation of CREB by ISO was prevented by U0126, an inhibitor of mitogen-activated protein kinase.

CONCLUSIONS

Our data first demonstrate that diazoxide mitigates hypertrophy by preventing an increase in miR-132 expression. The mechanism likely involves less ROS production leading to less phosphorylation of CREB. Our data further show that ROS enhance miR-132 transcription, and that ISO effects are probably mediated by the mitogen-activated protein kinase pathway.

MicroRNA-132 controls water homeostasis through regulating MECP2-mediated vasopressin synthesis

Fine-tuning of the body’s water balance is regulated by vasopressin (AVP), which induces the expression and apical membrane insertion of aquaporin-2 water channels and subsequent water reabsorption in the kidney. Here we demonstrate that silencing of microRNA-132 (miR-132) in mice causes severe weight loss due to acute diuresis coinciding with increased plasma osmolality, reduced renal total and plasma membrane expression of aquaporin-2, and abrogated increase in AVP levels. Infusion with synthetic AVP fully reversed the antagomir-132-induced diuresis, and low-dose intracerebroventricular administration of antagomir-132 similarly caused acute diuresis. Central and intracerebroventricular antagomir-132 injection both decreased hypothalamic AVP mRNA levels. At the molecular level, antagomir-132 increased the in vivo and in vitro mRNA expression of methyl-CpG-binding protein-2 (MECP2), which is a miR-132 target and which blocks AVP gene expression by binding its enhancer region. In line with this, treatment of hypothalamic N6 cells with a high-salt solution increased its miR-132 levels, whereas it attenuated endogenous Mecp2 mRNA levels. In conclusion, we identified miR-132 as a first miRNA regulating the osmotic balance by regulating the hypothalamic AVP gene mRNA expression.

Significance of non-coding circular RNAs and micro RNAs in the pathogenesis of cardiovascular diseases

Heart failure, coronary artery disease and myocardial infarction are the most prominent cardiovascular diseases contributing significantly to death worldwide. In the majority of situations, except for surgical interventions and transplantation, there are no reliable therapeutic approaches available to address these health problem. Despite several advances that led to the development of biomarkers and therapies based on the renin–angiotensin system, adrenergic pathways, etc, more definitive and consistent biomarkers and specific target based molecular therapies are still being sought. Recent advances in the field of genomic research has helped in identifying non-coding RNAs, including circular RNAs, piRNAs, micro RNAs, and long non-coding RNAs, that play a significant role in the regulation of gene expression and function and have direct impact on pathophysiological mechanisms. This new knowledge is currently being explored with much hope for the development of novel treatments and biomarkers. Circular RNAs and micro RNAs have been described in myocardium and aortic valves and were shown to be involved in the regulation of pathophysiological processes that potentially contribute to cardiovascular diseases. Approximately 32 000 human exonic circular RNAs have been catalogued and their functions are still being ascertained. In the heart, circular RNAs were shown to bind micro RNAs in a specific manner and regulate the expression of transcription factors and stress response genes, and expression of these non-coding RNAs were found to change in conditions such as cardiac hypertrophy, heart failure and cardiac remodelling, reflecting their significance as diagnostic and prognostic biomarkers. In this review, we address the present state of understanding on the biogenesis, regulation and pathophysiological roles of micro and circular RNAs in cardiovascular diseases, and on the potential future perspectives on their use as biomarkers and therapeutic agents.

MMISH: Multicolor microRNA in situ hybridization for paraffin embedded samples

•

A robust, sensitive and flexible multicolor miRNA in situ hybridization (MMISH) technique for paraffin embedded sections can be combined with both immunohistochemical and immunofluorescent staining.

•

Usage of urea in our buffers which enhances the target-probe affinity by preventing intermolecular interaction within miRNAs or individual probes, and by reversing the EDC fixation induced epitope loss by denaturing the antigens, less toxic compared to toxic formamide.

•

Second, it can be combined with immunofluorescent stainings, which allows one to analyze the expression and precise (sub)cellular location of the miRNA of interest.

To understand and assess the roles of miRNAs, visualization of the expression patterns of specific miRNAs is needed at the cellular level in a wide variety of different tissue types. Although miRNA in situ hybridization techniques have been greatly improved in recent years, they remain difficult to routinely perform due to the complexity of the procedure. In addition, as it is crucial to define which tissues or cells are expressing a particular miRNA in order to elucidate the biological function of the miRNA, incorporation of additional stainings for different cellular markers is necessary. Here, we describe a robust and flexible multicolor miRNA in situ hybridization (MMISH) technique for paraffin embedded sections. We show that the miRNA in situ protocol is sensitive and highly specific and can successfully be combined with both immunohistochemical and immunofluorescent stainings.

A new miRNA regulator, miR-672, reduces cardiac hypertrophy by inhibiting JUN expression

Cardiac hypertrophy is one of the initial symptoms of many heart diseases. We found that miR-672-5p may participate in the regulation of heart disease development in mouse, but the association between miR-672-5p and cardiac hypertrophy remains unclear. In the present study, we found that the abundance of miR-672-5p decreased in hypertrophic cardiomyocytes induced by phenylephrine, angiotensin II (Ang II) and insulin-like growth factor 1. Putative target genes of miR-672-5p were identified using four pipelines, miRWalk, miRanda, RNA22 and Targetscan, and a total of 834 genes were predicted by all four pipelines. Among these target genes, 98 were associated with the development of heart disease. PPI networks showed that the Jun proto-oncogene product (JUN), a subunit of the AP-1 transcription factor, had the highest node degree, and it was defined as the hub gene of the PPI networks. Luciferase assays showed that miR-672-5p bound to the 3' UTR of the JUN gene and decreased luciferase activity, indicating that JUN is a target of miR-672-5p. Finally, we found that increasing the abundance of miR-672-5p in cardiomyocytes controlled the relative cell area in Ang II-stimulated hypertrophic cardiomyocytes. Correspondingly, the abundance of JUN, a target of miR-672-5p, was decreased in hypertrophic cardiomyocytes on both mRNA and protein levels, implying that miR-672-5p had suppressive effects on cardiac hypertrophy through regulating the expression of Jun in cardiomyocytes.

MiR-31a-5p protects myocardial cells against apoptosis by targeting Tp53

The pathogenesis and progression of heart failure (HF) involves multiple mechanisms, including the increased activity of the renin-angiotensin-aldosterone system, apoptosis and differential expression of microRNAs (miRNAs/miRs). Our previous study revealed an increase in miR‑31a‑5p levels in the failing hearts of a rat HF model. In the present study, whether and how miR‑31a‑5p mediates angiotensin II (AngII)‑induced apoptosis in the cardiac H9C2 cell line, was investigated using molecular biological approaches, including reverse transcription followed by quantitative polymerase chain reaction, western blotting, RNA arrays, and mutagenesis. It was demonstrated that AngII stimulation increased apoptosis and decreased miR‑31a‑5p expression, which coincided with increased tumor protein p53 (Tp53) levels. Overexpression of miR‑31a‑5p significantly suppressed the AngII‑induced apoptotic rate and caspase‑3 activity, while suppression of miR‑31a‑5p did the opposite. A total of 16 proapoptotic genes that were downregulated and 4 antiapoptotic genes that were upregulated in the miR‑31a‑5p‑overexpressed cells were identified. It was also revealed that Tp53 mRNA contained the seed sequence in its 3'‑untranslated region for miR‑31a‑5p binding. The luciferase reporter analysis showed that miR‑31a‑5p repressed the luciferase activity of the wild‑type seed sequence, but not the mutated seed sequence fused to a reporter construct. Thus, it was demonstrated that miR‑31a‑5p mediated AngII‑triggered apoptosis in myocardial cells at least partially through targeting Tp53. These findings advance the understanding of the functional interaction between miRNAs and Tp53 in the setting of cardiac diseases. Further work is required to explore whether miR‑31a‑5p can serve as a therapeutic target for HF treatment in vivo.

Long noncoding RNA: a new contributor and potential therapeutic target in fibrosis

Fibrosis is the excess deposition of extracellular matrix components which occur in multiple organs and ultimately leads to organ failure. Long noncoding RNAs (lncRNAs) are a kind of noncoding RNAs longer than approximately 200 nucleotides with no protein-encoding capacity. A growing body of evidence suggests that lncRNAs are also involved in tissues fibrosis in several organs, such as lungs fibrosis, liver fibrosis, renal fibrosis and cardiac fibrosis. In this review, we summarized the current studies of lncRNAs in the process of fibrosis and hopefully aid in better understanding the molecular mechanism of fibrosis and provide a basis to explore new therapeutic targets of fibrosis.

Bioinformatic analysis of microRNA-mRNA expression profiles of bladder tissue induced by bladder outlet obstruction in a rat model

Various microRNAs (miRNAs) have previously been demonstrated to exhibit an association with the process of bladder remodeling, induced by bladder outlet obstruction (BOO). However, little is known about miRNA and gene expression profiles and the molecular mechanism underlying bladder pathophysiological alterations. The present study used bioinformatic analysis technology to examine the altered miRNA and mRNA expression profiles of bladder tissue in a rat model of BOO and validate the involved signaling pathways. The gene expression profile data was downloaded from Gene Expression Omnibus (GEO), and the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) were screened. Potential target genes of DEMs were predicted. The target genes and DEGs were used for further gene ontology (GO) analysis followed by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis using the Database for Annotation, Visualization and Integrated Discovery. The present study additionally constructed a DEM‑DEG interaction network. A total of 9 DEMs (3 upregulated and 6 downregulated) were identified; 664 DEGs were screened. KEGG analysis revealed that the DEGs were involved in the regulation of the actin cytoske-leton, extracellular matrix (ECM) remodeling, cell adhesion and the cell cycle. Additionally, KEGG classification indicated that these genes were important in angiogenesis, and in the p53 and transforming growth factor‑β signaling pathways. Notably, rno‑miRNA (miR)‑26b and rno‑miR‑101b were the two larger nodes of the 7 obstruction‑associated DEMs and interacted with 32 and 27 DEGs, respectively. On removal of obstruction, few DEMs were present; however, 370 genes exhibited the opposite expression trend. The majority of pathways enriched for the DEGs were identified and were associated with ECM‑receptor interaction and focal adhesion. In the DEM‑DEG regulatory network, miR‑495, miR‑494 and their target genes were significantly differentially expressed. The present study demonstrated that miRNAs and genes may be potential biomarkers of bladder remodeling induced by BOO, and additionally provided novel insights into the molecular mechanisms underlying this disorder.

Akt signaling as a mediator of cardiac adaptation to low birth weight

Intrauterine insults, such as poor nutrition and placental insufficiency, can alter cardiomyocyte development, and this can have significant long-term implications for heart health. Consequently, epidemiological studies have shown that low-birth-weight babies have an increased risk of death from cardiovascular disease in adult life. In addition, intrauterine growth restriction can result in increased left ventricular hypertrophy, which is the strongest predictor for poor health outcomes in cardiac patients. The mechanisms responsible for these associations are not clear, but a suboptimal intrauterine environment can program alternative expression of genes such as cardiac IGF-2/H19, IGF-2R and AT₁R through either an increase or decrease in DNA methylation or histone acetylation at specific loci. Furthermore, hypoxia and other intrauterine insults can also activate the IGF-1 receptor via IGF-1 and IGF-2, and the AT₁ receptor via angiotensin signaling pathways; both of which can result in the phosphorylation of Akt and the activation of a range of downstream pathways. In turn, Akt activation can increase cardiac angiogenesis and cardiomyocyte apoptosis and promote a reversion of metabolism in postnatal life to a fetal phenotype, which involves increased reliance on glucose. Cardiac Akt can also be indirectly regulated by microRNAs and conversely can target microRNAs that will eventually affect other specific cardiac genes and proteins. This review aims to discuss our understanding of this complex network of interactions, which may help explain the link between low birth weight and the increased risk of cardiovascular disease in adult life.

Characterization of miRNA-regulated networks, hubs of signaling, and biomarkers in obstruction-induced bladder dysfunction

Bladder outlet obstruction (BOO) induces significant organ remodeling, leading to lower urinary tract symptoms accompanied by urodynamic changes in bladder function. Here, we report mRNA and miRNA transcriptome sequencing of bladder samples from human patients with different urodynamically defined states of BOO. Patients' miRNA and mRNA expression profiles correlated with urodynamic findings. Validation of RNA sequencing results in an independent patient cohort identified combinations of 3 mRNAs (NRXN3, BMP7, UPK1A) and 3 miRNAs (miR-103a-3p, miR-10a-5p, miR-199a-3p) sufficient to discriminate between bladder functional states. All BOO patients shared cytokine and immune response pathways, TGF-β and NO signaling pathways, and hypertrophic PI3K/AKT signaling pathways. AP-1 and NFkB were dominant transcription factors, and TNF-α was the top upstream regulator. Integrated miRNA-mRNA expression analysis identified pathways and molecules targeted by differentially expressed miRNAs. Molecular changes in BOO suggest an increasing involvement of miRNAs in the control of bladder function from the overactive to underactive/acontractile states.

MicroRNA and Heart Failure

Heart failure (HF) imposes significant economic and public health burdens upon modern society. It is known that disturbances in neurohormonal status play an important role in the pathogenesis of HF. Therapeutics that antagonize selected neurohormonal pathways, specifically the renin-angiotensin-aldosterone and sympathetic nervous systems, have significantly improved patient outcomes in HF. Nevertheless, mortality remains high with about 50% of HF patients dying within five years of diagnosis thus mandating ongoing efforts to improve HF management. The discovery of short noncoding microRNAs (miRNAs) and our increasing understanding of their functions, has presented potential therapeutic applications in complex diseases, including HF. Results from several genome-wide miRNA studies have identified miRNAs differentially expressed in HF cohorts suggesting their possible involvement in the pathogenesis of HF and their potential as both biomarkers and as therapeutic targets. Unravelling the functional relevance of miRNAs within pathogenic pathways is a major challenge in cardiovascular research. In this article, we provide an overview of the role of miRNAs in the cardiovascular system. We highlight several HF-related miRNAs reported from selected cohorts and review their putative roles in neurohormonal signaling.

The two faces of miR-29

Diabetes mellitus is a metabolic homeostasis disease that contributes to additional comorbidities such as cardiovascular disease (CVD) and cancer. It has a long undiagnosed latent period during which there can be irreparable damage to the pancreas and cardiovascular tissues. Recent studies have highlighted the roles of several microRNAs in CVD. Determining the microRNAs that link diabetes mellitus and CVD is an important topic to be explored. In the present review, we discuss the microRNAs that contribute to the progression of diabetes mellitus and CVD and focus on the miR-29 family microRNAs whose expression is upregulated by hyperglycemia and proinflammatory cytokines, the hallmarks of diabetes mellitus. Upregulation of miR-29 expression is a key factor in the loss of pancreatic β cells and development of the first stage of type 1 diabetes mellitus (T1DM). Additionally, miR-29-mediated suppression of myeloid cell leukemia 1 (MCL-1), an important prosurvival protein, underlies Marfan's syndrome, abdominal aortic aneurysm, and diabetes mellitus-associated cardiomyocyte disorganization. Suppression of miR-29 expression and subsequent increase in the prosurvival MCL-1, however, promotes tumor development. Therefore, miR-29 mimics that suppress MCL-1 are hailed as tumor suppressors. The critical question is whether an increase in miR-29 levels is well tolerated in conditions of comorbidities in which insulin resistance is an underlying disease. In light of increasing awareness of the interconnection of diabetes mellitus, CVD, and cancer, it is of utmost importance to understand the mechanism of action of current treatment options on all of the comorbidities and careful evaluation of cardiovascular toxicity must accompany any treatment paradigm that increases miR-29 levels.

A critical role of cardiac fibroblast-derived exosomes in activating renin angiotensin system in cardiomyocytes

Chronic activation of the myocardial renin angiotensin system (RAS) elevates the local level of angiotensin II (Ang II) thereby inducing pathological cardiac hypertrophy, which contributes to heart failure. However, the precise underlying mechanisms have not been fully delineated. Herein we report a novel paracrine mechanism between cardiac fibroblasts (CF)s and cardiomyocytes whereby Ang II induces pathological cardiac hypertrophy. In cultured CFs, Ang II treatment enhanced exosome release via the activation of Ang II receptor types 1 (AT1R) and 2 (AT2R), whereas lipopolysaccharide, insulin, endothelin (ET)-1, transforming growth factor beta (TGFβ)1 or hydrogen peroxide did not. The CF-derived exosomes upregulated the expression of renin, angiotensinogen, AT1R, and AT2R, downregulated angiotensin-converting enzyme 2, and enhanced Ang II production in cultured cardiomyocytes. In addition, the CF exosome-induced cardiomyocyte hypertrophy was blocked by both AT1R and AT2R antagonists. Exosome inhibitors, GW4869 and dimethyl amiloride (DMA), inhibited CF-induced cardiomyocyte hypertrophy with little effect on Ang II-induced cardiomyocyte hypertrophy. Mechanistically, CF exosomes upregulated RAS in cardiomyocytes via the activation of mitogen-activated protein kinases (MAPKs) and Akt. Finally, Ang II-induced exosome release from cardiac fibroblasts and pathological cardiac hypertrophy were dramatically inhibited by GW4869 and DMA in mice. These findings demonstrate that Ang II stimulates CFs to release exosomes, which in turn increase Ang II production and its receptor expression in cardiomyocytes, thereby intensifying Ang II-induced pathological cardiac hypertrophy. Accordingly, specific targeting of Ang II-induced exosome release from CFs may serve as a novel therapeutic approach to treat cardiac pathological hypertrophy and heart failure.

Role of MicroRNAs in Renin-Angiotensin-Aldosterone System-Mediated Cardiovascular Inflammation and Remodeling

MicroRNAs are endogenous regulators of gene expression either by inhibiting translation or protein degradation. Recent studies indicate that microRNAs play a role in cardiovascular disease and renin-angiotensin-aldosterone system- (RAAS-) mediated cardiovascular inflammation, either as mediators or being targeted by RAAS pharmacological inhibitors. The exact role(s) of microRNAs in RAAS-mediated cardiovascular inflammation and remodeling is/are still in early stage of investigation. However, few microRNAs have been shown to play a role in RAAS signaling, particularly miR-155, miR-146a/b, miR-132/122, and miR-483-3p. Identification of specific microRNAs and their targets and elucidating microRNA-regulated mechanisms associated RAS-mediated cardiovascular inflammation and remodeling might lead to the development of novel pharmacological strategies to target RAAS-mediated vascular pathologies. This paper reviews microRNAs role in inflammatory factors mediating cardiovascular inflammation and RAAS genes and the effect of RAAS pharmacological inhibition on microRNAs and the resolution of RAAS-mediated cardiovascular inflammation and remodeling. Also, this paper discusses the advances on microRNAs-based therapeutic approaches that may be important in targeting RAAS signaling.

The ACE2/Apelin Signaling, MicroRNAs, and Hypertension

The renin-angiotensin aldosterone system (RAAS) plays a pivotal role in the development of hypertension. Angiotensin converting enzyme 2 (ACE2), which primarily metabolises angiotensin (Ang) II to generate the beneficial heptapeptide Ang-(1-7), serves as a negative regulator of the RAAS. Apelin is a second catalytic substrate for ACE2 and functions as an inotropic and cardiovascular protective peptide. The physiological effects of Apelin are exerted through binding to its receptor APJ, a seven-transmembrane G protein-coupled receptor that shares significant homology with the Ang II type 1 receptor (AT1R). The deregulation of microRNAs, a class of short and small noncoding RNAs, has been shown to involve cardiovascular remodeling and pathogenesis of hypertension via the activation of the Ang II/AT1R pathway. MicroRNAs are linked with modulation of the ACE2/Apelin signaling, which exhibits beneficial effects in the cardiovascular system and hypertension. The ACE2-coupled crosstalk among the RAAS, the Apelin system, and microRNAs provides an important mechanistic insight into hypertension. This paper focuses on what is known about the ACE2/Apelin signaling and its biological roles, paying particular attention to interactions and crosstalk among the ACE2/Apelin signaling, microRNAs, and hypertension, aiming to facilitate the exploitation of new therapeutic medicine to control hypertension.