Role of miR-145 in cardiac myofibroblast differentiation

MSC-extracellular vesicle microRNAs target host cell-entry receptors in COVID-19: in silico modeling for in vivo validation

BACKGROUND

Coronavirus disease 2019 (COVID-19) has created a global pandemic with significant morbidity and mortality. SARS-CoV-2 primarily infects the lungs and is associated with various organ complications. Therapeutic approaches to combat COVID-19, including convalescent plasma and vaccination, have been developed. However, the high mutation rate of SARS-CoV-2 and its ability to inhibit host T-cell activity pose challenges for effective treatment. Mesenchymal stem cells (MSCs) and their extracellular vesicles (MSCs-EVs) have shown promise in COVID-19 therapy because of their immunomodulatory and regenerative properties. MicroRNAs (miRNAs) play crucial regulatory roles in various biological processes and can be manipulated for therapeutic purposes.

OBJECTIVE

We aimed to investigate the role of lyophilized MSC-EVs and their microRNAs in targeting the receptors involved in SARS-CoV-2 entry into host cells as a strategy to limit infection. In silico microRNA prediction, structural predictions of the microRNA-mRNA duplex, and molecular docking with the Argonaut protein were performed.

METHODS

Male Syrian hamsters infected with SARS-CoV-2 were treated with human Wharton's jelly-derived Mesenchymal Stem cell-derived lyophilized exosomes (Bioluga Company)via intraperitoneal injection, and viral shedding was assessed. The potential therapeutic effects of MSCs-EVs were measured via histopathology of lung tissues and PCR for microRNAs.

RESULTS

The results revealed strong binding potential between miRNA‒mRNA duplexes and the AGO protein via molecular docking. MSCs-EVs reduced inflammation markers and normalized blood indices via the suppression of viral entry by regulating ACE2 and TMPRSS2 expression. MSCs-EVs alleviated histopathological aberrations. They improved lung histology and reduced collagen fiber deposition in infected lungs.

CONCLUSION

We demonstrated that MSCs-EVs are a potential therapeutic option for treating COVID-19 by preventing viral entry into host cells.

MicroRNA miR-145-5p Inhibits Cutaneous Wound Healing by Targeting PDGFD in Diabetic Foot Ulcer

Diabetic foot ulcer (DFU) is one major, common and serious chronic complication of diabetes mellitus, which is characterized by high incidence, high risk, high burden, and high treatment difficulty and is a leading cause of disability and death in patients with diabetes. Long-term hyperglycemia can result in cellular dysfunction of fibroblasts, which play pivotal roles in wound healing. MicroRNAs (miRNAs) were reported to mediate the pathological processes of multiple diseases, including diabetic wound healing. This research aimed to investigate the functional role of miR-145-5p in high-glucose (HG)-exposed fibroblasts and in DFU mouse models. Human foreskin fibroblast cells (HFF-1) were stimulated by HG to induce cell injury. MiR-145-5p level in HG-stimulated HFF-1 cells was detected via RT-qPCR. The binding between miR-145-5p and PDGFD was validated by Luciferase reporter assay. The effects of the miR-145-5p/PDGFD axis on the viability, migration, and apoptosis of HG-exposed HFF-1 cells were determined by CCK-8, wound healing, and flow cytometry assays. DFU mouse models were subcutaneously injected at the wound edges with miR-145-5p inhibitor/mimics. Images of the wounds were captured on day 0 and 8 post-injection, and wound samples were collected after mice were sacrificed for histological analysis by H&E staining. HG decreased cell viability and increased miR-145-5p expression in HFF-1 cells in a dose- and time-dependent manner. MiR-145-5p downregulation promoted cell viability and migration and inhibited cell apoptosis of HG-stimulated HFF-1 cells, while miR-145-5p overexpression exerted an opposite effect on cell viability, migration, and apoptosis. PDGFD was a direct target gene of miR-145-5p, whose silencing reversed the influence of miR-145-5p downregulation on HG-induced cellular dysfunction of HFF-1 cells. Additionally, downregulating miR-145-5p facilitated while overexpressing miR-145-5p inhibited wound healing in DFU mouse models. MiR-145-5p level was negatively associated with PDGFD level in wound tissue samples of DFU mouse models. MiR-145-5p inhibition improves wound healing in DFU through upregulating PDGFD expression.

Emerging roles of non-coding RNAs in fibroblast to myofibroblast transition and fibrotic diseases

The transition of fibroblasts to myofibroblasts (FMT) represents a pivotal process in wound healing, tissue repair, and fibrotic diseases. This intricate transformation involves dynamic changes in cellular morphology, gene expression, and extracellular matrix remodeling. While extensively studied at the molecular level, recent research has illuminated the regulatory roles of non-coding RNAs (ncRNAs) in orchestrating FMT. This review explores the emerging roles of ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), in regulating this intricate process. NcRNAs interface with key signaling pathways, transcription factors, and epigenetic mechanisms to fine-tune gene expression during FMT. Their functions are critical in maintaining tissue homeostasis, and disruptions in these regulatory networks have been linked to pathological fibrosis across various tissues. Understanding the dynamic roles of ncRNAs in FMT bears therapeutic promise. Targeting specific ncRNAs holds potential to mitigate exaggerated myofibroblast activation and tissue fibrosis. However, challenges in delivery and specificity of ncRNA-based therapies remain. In summary, ncRNAs emerge as integral regulators in the symphony of FMT, orchestrating the balance between quiescent fibroblasts and activated myofibroblasts. As research advances, these ncRNAs appear to be prospects for innovative therapeutic strategies, offering hope in taming the complexities of fibrosis and restoring tissue equilibrium.

Defining the Role of the miR-145-KLF4-αSMA Axis in Mitral Valvular Interstitial Cell Activation in Myxomatous Mitral Valve Prolapse Using the Canine Model

Mitral valve prolapse (MVP) is a common valvular disease, affecting 2-3% of the adult human population and is a degenerative condition. A total of 5-10% of the afflicted will develop severe mitral regurgitation, cardiac dysfunction, congestive heart failure, and sudden cardiac death. Naturally occurring myxomatous MVP in dogs closely resembles MVP in humans structurally, and functional consequences are similar. In both species, valvular interstitial cells (VICs) in affected valves exhibit phenotype consistent with activated myofibroblasts with increased alpha-smooth muscle actin (αSMA) expression. Using VICs collected from normal and MVP-affected valves of dogs, we analyzed the miRNA expression profile of the cells and their associated small extracellular vesicles (sEV) using RNA sequencing to understand the role of non-coding RNAs and sEV in MVP pathogenesis. miR-145 was shown to be upregulated in both the affected VICs and sEV, and overexpression of miR-145 by mimic transfection in quiescent VIC recapitulates the activated myofibroblastic phenotype. Concurrently, KLF4 expression was noted to be suppressed by miR-145, confirming the miR-145-KLF4-αSMA axis. Targeting this axis may serve as a potential therapy in controlling pathologic abnormalities found in MVP valves.

lncRNA TUG1 as potential novel biomarker for prognosis of cardiovascular diseases

Globally, cardiovascular diseases (CVDs) are among the leading causes of death. In light of the high prevalence and mortality of CVDs, it is imperative to understand the molecules involved in CVD pathogenesis and the signaling pathways that they initiate. This may facilitate the development of more precise and expedient diagnostic techniques, the identification of more effective prognostic molecules and the identification of potential therapeutic targets. Numerous studies have examined the role of lncRNAs, such as TUG1, in CVD pathogenesis in recent years. According to this review article, TUG1 can be considered a biomarker for predicting the prognosis of CVD.

Bidirectional negative feedback actions of DNMT3A and miR-145 in regulating autophagy in cardiac fibroblasts and affecting myocardial fibrosis

Epigenetic regulation has crucial implications for myocardial fibrosis. It has been reported that autophagy, regulated by miR-145, is implicated in the proliferation and fibrosis of cardiac fibroblasts (CFs). However, how it works during the process remains unclear. This study explored the exact effects of epigenetic regulation of miR-145 expression on autophagy, proliferation, and fibrosis of CFs. To examine the expression levels of myocardial fibrosis markers (α-SMA and collagen I), autophagy-related proteins (LC3I, LC3II, p62), DNMT3A, and miR-145, qRT-PCR and western blot were employed. And the proliferation of CFs was detected by CCK-8 and ErdU. As for the determination of the binding relationship between DNMT3A and miR-145, dual-luciferase assay was conducted. Next, the detection of the methylation level of the pre-miR-145 promoter region was completed by MSP. And the verification of the effect of the DNMT3A/miR-145 axis on myocardial fibrosis was accomplished by constructing mouse myocardial infarction (MI) models based on the ligation of the left anterior descending method. In TGF-β1-activated CFs, remarkable up-regulation of DNMT3 and considerable down-regulation of miR-145 were observed. And further experiments indicated that DNMT3A was able to down-regulate miR-145 expression by maintaining the hypermethylation level of the pre-miR-145 promoter region. In addition, DNMT3A expression could be directly targeted and negatively modulated by miR-145. Moreover, in vitro cell experiments and mouse MI models demonstrated that DNMT3A overexpression could inhibit autophagy, and promote cell proliferation and fibrosis of CFs. However, this kind of effect could be reversed by miR-145 overexpression. In summary, myocardial fibroblast autophagy can be regulated by bidirectional negative feedback actions of DNMT3A and miR-145, thus affecting myocardial fibrosis. This finding will provide a potential target for the clinical treatment of myocardial fibrosis.

Cardiovascular complications of diabetes: role of non-coding RNAs in the crosstalk between immune and cardiovascular systems

Diabetes mellitus, a group of metabolic disorders characterized by high levels of blood glucose caused by insulin defect or impairment, is a major risk factor for cardiovascular diseases and related mortality. Patients with diabetes experience a state of chronic or intermittent hyperglycemia resulting in damage to the vasculature, leading to micro- and macro-vascular diseases. These conditions are associated with low-grade chronic inflammation and accelerated atherosclerosis. Several classes of leukocytes have been implicated in diabetic cardiovascular impairment. Although the molecular pathways through which diabetes elicits an inflammatory response have attracted significant attention, how they contribute to altering cardiovascular homeostasis is still incompletely understood. In this respect, non-coding RNAs (ncRNAs) are a still largely under-investigated class of transcripts that may play a fundamental role. This review article gathers the current knowledge on the function of ncRNAs in the crosstalk between immune and cardiovascular cells in the context of diabetic complications, highlighting the influence of biological sex in such mechanisms and exploring the potential role of ncRNAs as biomarkers and targets for treatments. The discussion closes by offering an overview of the ncRNAs involved in the increased cardiovascular risk suffered by patients with diabetes facing Sars-CoV-2 infection.

The Role of ncRNAs in Cardiac Infarction and Regeneration

Myocardial infarction is the most prevalent cardiovascular disease worldwide, and it is defined as cardiomyocyte cell death due to a lack of oxygen supply. Such a temporary absence of oxygen supply, or ischemia, leads to extensive cardiomyocyte cell death in the affected myocardium. Notably, reactive oxygen species are generated during the reperfusion process, driving a novel wave of cell death. Consequently, the inflammatory process starts, followed by fibrotic scar formation. Limiting inflammation and resolving the fibrotic scar are essential biological processes with respect to providing a favorable environment for cardiac regeneration that is only achieved in a limited number of species. Distinct inductive signals and transcriptional regulatory factors are key components that modulate cardiac injury and regeneration. Over the last decade, the impact of non-coding RNAs has begun to be addressed in many cellular and pathological processes including myocardial infarction and regeneration. Herein, we provide a state-of-the-art review of the current functional role of diverse non-coding RNAs, particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), in different biological processes involved in cardiac injury as well as in distinct experimental models of cardiac regeneration.

Noncoding RNAs: Master Regulator of Fibroblast to Myofibroblast Transition in Fibrosis

Myofibroblasts escape apoptosis and proliferate abnormally under pathological conditions, especially fibrosis; they synthesize and secrete a large amount of extracellular matrix (ECM), such as α-SMA and collagen, which leads to the distortion of organ parenchyma structure, an imbalance in collagen deposition and degradation, and the replacement of parenchymal cells by fibrous connective tissues. Fibroblast to myofibroblast transition (FMT) is considered to be the main source of myofibroblasts. Therefore, it is crucial to explore the influencing factors regulating the process of FMT for the prevention, treatment, and diagnosis of FMT-related diseases. In recent years, non-coding RNAs, including microRNA, long non-coding RNAs, and circular RNAs, have attracted extensive attention from scientists due to their powerful regulatory functions, and they have been found to play a vital role in regulating FMT. In this review, we summarized ncRNAs which regulate FMT during fibrosis and found that they mainly regulated signaling pathways, including TGF-β/Smad, MAPK/P38/ERK/JNK, PI3K/AKT, and WNT/β-catenin. Furthermore, the expression of downstream transcription factors can be promoted or inhibited, indicating that ncRNAs have the potential to be a new therapeutic target for FMT-related diseases.

miR-145 from Bone Marrow Mesenchymal Stem Cells (BMSC) Improves Cardiac Function After Myocardial Infarction in Rat with Diabetes

This study assesses the role of miR-145 from BMSC in the cardiac function after MI in rat with diabetes. Rat with T1DM model was established and then were treated with PBS, DM-BMSC with overexpression of miR-145, BMSC with the knockdown of miR-145 respectively after twenty-four hours followed by analysis of the remodeling of vessels and protein, mRNA expressions. miR-145 in DM-BMSC was significantly reduced compared with control group and DM-BMSC prolonged the survival rate of rats. The formation of blood capillary and axon growth in DM-BMSC was increased and decreased in BMSC with knockdown of miR-145. The therapeutic action of DM-BMSC could be improved notably and remodeling of vessels and protein was increased. Smad1 was a target gene of miR-145. In conclusion, cardiac function and neurological recovery in MI is improved by miR-145 through targeting Smad1 expression, indicating that miR-145 might be a novel target for the treatment of MI.

Targeting Myocardial Fibrosis—A Magic Pill in Cardiovascular Medicine?

Fibrosis, characterized by an excessive accumulation of extracellular matrix, has long been seen as an adaptive process that contributes to tissue healing and regeneration. More recently, however, cardiac fibrosis has been shown to be a central element in many cardiovascular diseases (CVDs), contributing to the alteration of cardiac electrical and mechanical functions in a wide range of clinical settings. This paper aims to provide a comprehensive review of cardiac fibrosis, with a focus on the main pathophysiological pathways involved in its onset and progression, its role in various cardiovascular conditions, and on the potential of currently available and emerging therapeutic strategies to counteract the development and/or progression of fibrosis in CVDs. We also emphasize a number of questions that remain to be answered, and we identify hotspots for future research.

MicroRNA‑146a attenuates isoproterenol‑induced cardiac fibrosis by inhibiting FGF2

Cardiac fibrosis is a key factor of heart failure. Increasing evidence suggests that microRNAs (miRNAs/miRs) serve vital roles in the pathogenesis of cardiac fibrosis. The present study aimed to investigate the role of miR-146a-5p in isoproterenol (ISO)-induced cardiac fibrosis. Reverse transcription-quantitative PCR analysis demonstrated that miR-146a-5p expression was downregulated in ISO-treated rat heart tissue and ISO-induced cardiac fibroblasts (CFs). Conversely, the expression levels of basic fibroblast growth factor 2 (FGF2), collagen I and smooth muscle α-actin (α-SMA) were upregulated in ISO-treated rat cardiac tissue and CFs. Furthermore, viability and differentiation were inhibited in ISO-induced CFs transfected with miR-146a-5p mimics. Dual-luciferase reporter assay confirmed that miR-146a-5p targeted FGF2. Notably, FGF2 expression was suppressed following overexpression of miR-146a-5p, while FGF2 expression increased following miR-146a-5p knockdown. In addition, FGF2 knockdown suppressed the expression levels of FGF2, collagen I and α-SMA levels in CFs. Taken together, the results of the present study suggested that the miR-146a-5p/FGF2 pathway may be a novel therapy for cardiac fibrosis.

A New Hypothetical Concept in Metabolic Understanding of Cardiac Fibrosis: Glycolysis Combined with TGF-β and KLF5 Signaling

The accumulation of fibrosis in cardiac tissues is one of the leading causes of heart failure. The principal cellular effectors in cardiac fibrosis are activated fibroblasts and myofibroblasts, which serve as the primary source of matrix proteins. TGF-β signaling pathways play a prominent role in cardiac fibrosis. The control of TGF-β by KLF5 in cardiac fibrosis has been demonstrated for modulating cardiovascular remodeling. Since the expression of KLF5 is reduced, the accumulation of fibrosis diminishes. Because the molecular mechanism of fibrosis is still being explored, there are currently few options for effectively reducing or reversing it. Studying metabolic alterations is considered an essential process that supports the explanation of fibrosis in a variety of organs and especially the glycolysis alteration in the heart. However, the interplay among the main factors involved in fibrosis pathogenesis, namely TGF-β, KLF5, and the metabolic process in glycolysis, is still indistinct. In this review, we explain what we know about cardiac fibroblasts and how they could help with heart repair. Moreover, we hypothesize and summarize the knowledge trend on the molecular mechanism of TGF-β, KLF5, the role of the glycolysis pathway in fibrosis, and present the future therapy of cardiac fibrosis. These studies may target therapies that could become important strategies for fibrosis reduction in the future.

Krüppel-like factor (KLF)5: An emerging foe of cardiovascular health

Krüppel-like factors (KLFs) are DNA-binding transcriptional factors, which regulate various pathways that pertain to development, metabolism and other cellular mechanisms. KLF5 was first cloned in 1993 and by 1999, it was reported as the intestinal-enriched KLF. Beyond findings that have associated KLF5 with normal development and cancer, it has been associated with various types of cardiovascular (CV) complications and regulation of metabolic pathways in the liver, heart, adipose tissue and skeletal muscle. Specifically, increased KLF5 expression has been linked with cardiomyopathy in diabetes, end-stage heart failure, and as well as in vascular atherosclerotic lesions. In this review article, we summarize research findings about transcriptional, post-transcriptional and post-translational regulation of KLF5, as well as the role of KLF5 in the biology of cells and organs that affect cardiovascular health either directly or indirectly. Finally, we propose KLF5 inhibition as an emerging approach for cardiovascular therapeutics.

Modulation of miR-145-5p and miR-146b-5p levels is linked to reduced parasite load in H9C2 Trypanosoma cruzi infected cardiomyoblasts

In the heart tissue of acutely Trypanosoma cruzi-infected mice miR-145-5p and miR-146b-5p are, respectively, downregulated and upregulated. Here, we used the H9C2 rat cardiomyoblast cell line infected with the Colombian T. cruzi strain to investigate the parasite-host cell interplay, focusing on the regulation of miR-145-5p and miR-146b-5p expression. Next, we explored the effects of interventions with the trypanosomicidal drug Benznidazole (Bz) alone or combined with Pentoxifylline (PTX), a methylxanthine derivative shown to modulate immunological and cardiac abnormalities in a model of chronic chagasic cardiomyopathy, on parasite load and expression of miR-145-5p and miR-146b-5p. The infection of H9C2 cells with trypomastigote forms allowed parasite cycle with intracellular forms multiplication and trypomastigote release. After 48 and 144 h of infection, upregulation of miR-145-5p (24 h: 2.38 ± 0.26; 48 h: 3.15 ± 0.9-fold change) and miR-146b-5b (24 h: 2.60 ± 0.46; 48 h: 2.97 ± 0.23-fold change) was detected. The peak of both miRNA levels paralleled with release of trypomastigote forms. Addition of 3 µM and 10 µM of Bz 48 h after infection reduced parasite load but did not interfere with miR-145-5p and miR-146b-5p levels. Addition of PTX did not interfere with Bz-induced parasite control efficacy. Conversely, combined Bz + PTX treatment decreased the levels of both microRNAs, resembling the expression levels detected in non-infected H9C2 cells. Moreover, the use of miR-145-5p and miR-146b-5p mimic/inhibitor systems before infection of H9C2 cells decreased parasite load, 72 h postinfection. When H9C2 cells were treated with miR-145-5p and miR-146b-5p mimic/inhibitor 48 h after infection, all the used systems, except the miR-146b-5p inhibitor, reduced parasite load. Altogether, our data indicate that these microRNAs putatively control signaling pathways crucial for parasite–host cell interaction. Thus, miR-145-5p and miR-146b-5p deserve to be further investigated as biomarkers of parasite control and tools to identify therapeutic adjuvants to etiological treatment in Chagas disease.

Pulmonary AngII promotes LPS-induced lung inflammation by regulating microRNA-143

Angiotensin converting enzyme 2 (ACE2) is a terminal carboxypeptidase, which cleaves single terminal residues from several bioactive peptides such as Angiotensin II (AngII). Many investigations indicated that ACE2 functions in angiotensin system and plays a crucial role in inflammatory lung diseases. However, the mechanism behind the involvement of ACE2 in inflammatory lung disease has not been fully elucidated. In this study, BEAS-2B cells were treated with gradient concentration of AngII and lipopolysaccharide (LPS) to induce inflammatory condition. Quantitative RT-PCR was performed to detect the level of ACE2 and miR-143-3p. Western blotting and immunofluorescence assays were performed to measure the expression of related proteins. The levels of inflammatory cytokines and cell viability were respectively measured by ELISA and CCK-8 kits. And ACE2 activity was detected by corresponding commercial kits. Bioinformatics methods were employed to predict the potential microRNA targeting ACE2, which was then confirmed by dual luciferase reporter assay. The results showed that ACE2 expression and activity were time-dependently decreased in LPS group for the first 12 h, after which this tendency was reversed. AngII addition enhanced these effects, compared with LPS group. Additionally, the lowest ACE2 activity level was found in both LPS and AngII + LPS groups at 6 h. The number of nuclei and the ACE2 expression were decreased in LPS groups at 6 h and further reduced by addition of AngII, detected by immunofluorescence. Moreover, ACE2 was validated to be a direct target of miR-143-3p. Pretreatment of AngII and LPS regulated the activity of ACE2, increased the expression of proinflammatory cytokines and cell apoptosis and regulated the expression of Bax, Bcl-2 and cleaved caspase-3 in BEAS-2B cells, which could be reversed by transfecting miR-143-3p inhibitor. The results collectively suggest that AngII promotes LPS-induced inflammation by regulating miR-143-3p in BEAS-2B cells. Therefore, miR-143-3p is considered a potential molecular target for the treatment of lung inflammation.

miR-145 transgenic mice develop cardiopulmonary complications leading to postnatal death

BACKGROUND

Both downregulation and elevation of microRNA miR-145 has been linked to an array of cardiopulmonary phenotypes, and a host of studies suggest that it is an important contributor in governing the differentiation of cardiac and vascular smooth muscle cell types.

METHODS AND RESULTS

To better understand the role of elevated miR-145 in utero within the cardiopulmonary system, we utilized a transgene to overexpress miR-145 embryonically in mice and examined the consequences of this lineage-restricted enhanced expression. Overexpression of miR-145 has detrimental effects that manifest after birth as overexpressor mice are unable to survive beyond postnatal day 18. The miR-145 expressing mice exhibit respiratory distress and fail to thrive. Gross analysis revealed an enlarged right ventricle, and pulmonary dysplasia with vascular hypertrophy. Single cell sequencing of RNA derived from lungs of control and miR-145 transgenic mice demonstrated that miR-145 overexpression had global effects on the lung with an increase in immune cells and evidence of leukocyte extravasation associated with vascular inflammation.

CONCLUSIONS

These data provide novel findings that demonstrate a pathological role for miR-145 in the cardiopulmonary system that extends beyond its normal function in governing smooth muscle differentiation.

The Cell Surface Receptors Ror1/2 Control Cardiac Myofibroblast Differentiation

Background A hallmark of heart failure is cardiac fibrosis, which results from the injury-induced differentiation response of resident fibroblasts to myofibroblasts that deposit extracellular matrix. During myofibroblast differentiation, fibroblasts progress through polarization stages of early proinflammation, intermediate proliferation, and late maturation, but the regulators of this progression are poorly understood. Planar cell polarity receptors, receptor tyrosine kinase-like orphan receptor 1 and 2 (Ror1/2), can function to promote cell differentiation and transformation. In this study, we investigated the role of the Ror1/2 in a model of heart failure with emphasis on myofibroblast differentiation. Methods and Results The role of Ror1/2 during cardiac myofibroblast differentiation was studied in cell culture models of primary murine cardiac fibroblast activation and in knockout mouse models that underwent transverse aortic constriction surgery to induce cardiac injury by pressure overload. Expression of Ror1 and Ror2 were robustly and exclusively induced in fibroblasts in hearts after transverse aortic constriction surgery, and both were rapidly upregulated after early activation of primary murine cardiac fibroblasts in culture. Cultured fibroblasts isolated from Ror1/2 knockout mice displayed a proinflammatory phenotype indicative of impaired myofibroblast differentiation. Although the combined ablation of Ror1/2 in mice did not result in a detectable baseline phenotype, transverse aortic constriction surgery led to the death of all mice by day 6 that was associated with myocardial hyperinflammation and vascular leakage. Conclusions Together, these results show that Ror1/2 are essential for the progression of myofibroblast differentiation and for the adaptive remodeling of the heart in response to pressure overload.

Regulation of miRNAs by Natural Antioxidants in Cardiovascular Diseases: Focus on SIRT1 and eNOS

Cardiovascular diseases (CVDs) are the most common cause of morbidity and mortality worldwide. The potential benefits of natural antioxidants derived from supplemental nutrients against CVDs are well known. Remarkably, natural antioxidants exert cardioprotective effects by reducing oxidative stress, increasing vasodilation, and normalizing endothelial dysfunction. Recently, considerable evidence has highlighted an important role played by the synergistic interaction between endothelial nitric oxide synthase (eNOS) and sirtuin 1 (SIRT1) in the maintenance of endothelial function. To provide a new perspective on the role of natural antioxidants against CVDs, we focused on microRNAs (miRNAs), which are important posttranscriptional modulators in human diseases. Several miRNAs are regulated via the consumption of natural antioxidants and are related to the regulation of oxidative stress by targeting eNOS and/or SIRT1. In this review, we have discussed the specific molecular regulation of eNOS/SIRT1-related endothelial dysfunction and its contribution to CVD pathologies; furthermore, we selected nine different miRNAs that target the expression of eNOS and SIRT1 in CVDs. Additionally, we have summarized the alteration of miRNA expression and regulation of activities of miRNA through natural antioxidant consumption.

Cell type-specific microRNA therapies for myocardial infarction

Current interventions fail to recover injured myocardium after infarction and prompt the need for development of cardioprotective strategies. Of increasing interest is the therapeutic use of microRNAs to control gene expression through specific targeting of mRNAs. In this Review, we discuss current microRNA-based therapeutic strategies, describing the outcomes and limitations of key microRNAs with a focus on target cell types and molecular pathways. Last, we offer a perspective on the outlook of microRNA therapies for myocardial infarction, highlighting the outstanding challenges and emerging strategies.

Current knowledge of Krüppel-like factor 5 and vascular remodeling: providing insights for therapeutic strategies

Vascular remodeling is a pathological basis of various disorders. Therefore, it is necessary to understand the occurrence, prevention, and treatment of vascular remodeling. Krüppel-like factor 5 (KLF5) has been identified as a significant factor in cardiovascular diseases during the last two decades. This review provides a mechanism network of function and regulation of KLF5 in vascular remodeling based on newly published data and gives a summary of its potential therapeutic applications. KLF5 modulates numerous biological processes, which play essential parts in the development of vascular remodeling, such as cell proliferation, phenotype switch, extracellular matrix deposition, inflammation, and angiogenesis by altering downstream genes and signaling pathways. Considering its essential functions, KLF5 could be developed as a potent therapeutic target in vascular disorders.

MicroRNA-145 targets in cancer and the cardiovascular system: evidence for common signaling pathways

miRNAs are small regulatory RNAs which govern gene expression post-transcriptionally by primarily binding to the 3'-UTR of mRNA target genes. miR-145 is a well-studied miRNA that has been implicated in controlling a range of biological processes. miR-145 is expressed in a variety of tissues and cell types and acts as a tumor-suppressor by regulating target gene signaling pathways involved in different aspects of tumor growth and progression. There is also strong evidence that highlights the important functions of miR-145 in the cardiovascular system. Here, we review the mechanisms of miR-145 in tumorigenesis and cancer progression and compare and contrast with the roles of miR-145 in cardiovascular development and disease. We discuss the important targets of miR-145 in cancer and their possible link to the cardiovascular system.

miR-145 attenuates cardiac fibrosis through the AKT/GSK-3β/β-catenin signaling pathway by directly targeting SOX9 in fibroblasts

Myocardial infarction (MI) will inevitably result in cardiac fibrosis. In this study, we investigated the effect of microRNA-145 (miR-145) and transcription factor sex-determining region Y box 9 (SOX9) in the production of cardiac fibrosis induced by MI. MI rat models were established by left anterior descending coronary artery (LAD) occlusion. Four weeks after LAD, the cardiac fibrosis level was assessed by Masson's trichrome staining. Cardiac fibroblasts (CFs) exposed to hypoxia were used to simulate MI-induced fibrosis. Flow cytometry, cell counting kit-8, and transwell assays were used to examine changes in CF apoptosis, proliferation, and migration, respectively. miR-145 expression was measured by quantitative real-time polymerase chain reaction. Immunofluorescence and Western blot analysis were performed to determine the relative expression of proteins. In comparison to the sham-operated group, the expression of miR-145 was significantly downregulated in the infarction peripheral area, whereas, SOX9 was upregulated. In the infarcted heart, the overexpression of miR-145 significantly ameliorated cardiac fibrosis and cardiac function, and there was a negative correlation between miR-145 and SOX9 expressions in hypoxic CFs in vitro. In addition, SOX9 was verified to be a functional target of miR-145. Overexpression of miR-145 or inhibition of SOX9 decreased CF proliferation, migration, and fibrosis, but augmented their apoptotic rate. Moreover, the upregulation of miR-145 or suppression of SOX9 inhibited AKT and β-catenin signaling in hypoxic CFs. Taken together, this study highlights a potential treatment for cardiac fibrosis through the targeted regulation of SOX9 by miR-145, and our findings indicate that miR-145 exerts anti-fibrotic effects in MI via the negative regulation of SOX9 and its downstream AKT/GSK-3β/β-catenin pathways.

CircHIPK3 regulates cardiac fibroblast proliferation, migration and phenotypic switching through the miR-152-3p/TGF-β2 axis under hypoxia

Background

The occurrence of pathological cardiac fibrosis is attributed to tissue hypoxia. Circular RNAs play significant regulatory roles in multiple cardiovascular diseases and are involved in the regulation of physiological and pathophysiological processes. CircHIPK3 has been identified as the one of the most crucial regulators in cardiac fibrosis. However, the mechanisms by which circHIPK3 regulates cardiac fibrosis under hypoxia remain unclear. Our study aimed to determine circHIPK3 expression in cardiac fibroblasts (CFs) and investigate the functions of circHIPK3 in hypoxia environment.

Methods

The expression level of circHIPK3 in CFs under hypoxia (1% O₂) was analyzed by qRT-PCR. The role of circHIPK3 on the proliferation and migration of CFs were determined by EdU, cell wound scratch assay and cell cycle. The expression of proteins associated with phenotypic transformation in CFs in vitro was examined by immunofluorescence assay and western blot. Bioinformatics analysis, dual luciferase activity assay and RNA fluorescent in situ hybridization assay revealed that miR-152-3p was identified as a target of circHIPK3 and that TGF-β2 was targeted by miR-152-3p.

Results

CircHIPK3 expression was significantly upregulated in CFs in a hypoxic environment. In vitro, overexpressing circHIPK3 obviously promoted CF proliferation, migration and phenotypic changes under hypoxia, but those processes were suppressed by circHIPK3 silencing. CircHIPK3 acted as an endogenous miR-152-3p sponge and miR-152-3p aggravated circHIPK3 silencing induced inhibition of CF proliferation, migration, phenotypic transformation and TGF-β2 expression in vitro. In summary, circHIPK3 plays a pivotal role in the development of cardiac fibrosis by targeting the miR-152-3p/TGF-β2 axis.

Conclusions

These findings demonstrated that circHIPK3 acted as a miR-152-3p sponge to regulate CF proliferation, migration and phenotypic transformation through TGF-β2, revealing that modulation of circHIPK3 expression may represent a potential target to promote the transition of hypoxia-induced CFs to myofibroblasts.

Knock-out of MicroRNA 145 impairs cardiac fibroblast function and wound healing post-myocardial infarction

Prevention of infarct scar thinning and dilatation and stimulation of scar contracture can prevent progressive heart failure. Since microRNA 145 (miR-145) plays an important role in cardiac fibroblast response to wound healing and cardiac repair after an myocardial infarction (MI), using a miR-145 knock-out (KO) mouse model, we evaluated contribution of down-regulation of miR-145 to cardiac fibroblast and myofibroblast function during adverse cardiac remodelling. Cardiac function decreased more and the infarct size was larger in miR-145 KO than that in WT mice after MI and this phenomenon was accompanied by a decrease in cardiac fibroblast-to-myofibroblast differentiation. Quantification of collagen I and α-SMA protein levels as well as wound contraction revealed that transdifferentiation of cardiac fibroblasts into myofibroblasts was lower in KO than WT mice. In vitro restoration of miR-145 induced more differentiation of fibroblasts to myofibroblasts and this effect involved the target genes Klf4 and myocardin. MiR-145 contributes to infarct scar contraction in the heart and the absence of miR-145 contributes to dysfunction of cardiac fibroblast, resulting in greater infarct thinning and dilatation. Augmentation of miR-145 could be an attractive target to prevent adverse cardiac remodelling after MI by enhancing the phenotypic switch of cardiac fibroblasts to myofibroblasts.

Identification of Novel miRNAs Involved in Cardiac Repair Following Infarction in Fetal and Adolescent Sheep Hearts

Aims

Animal models have been used to show that there are critical molecular mechanisms that can be activated to induce myocardial repair at specific times in development. For example, specific miRNAs are critical for regulating the response to myocardial infarction (MI) and improving the response to injury. Manipulating these miRNAs in small animal models provides beneficial effects post-MI; however it is not known if these miRNAs are regulated similarly in large mammals. Studying a large animal where the timing of heart development in relation to birth is similar to humans may provide insights to better understand the capacity to repair a developing mammalian heart and its application to the adult heart.

Methods

We used a sheep model of MI that included permanent ligation of the left anterior descending (LAD) coronary artery. Surgery was performed on fetuses (at 105 days gestation when all cardiomyocytes are mononucleated and proliferative) and adolescent sheep (at 6 months of age when all cardiomyocytes contribute to heart growth by hypertrophy). A microarray was utilized to determine the expression of known miRNAs within the damaged and undamaged tissue regions in fetal and adolescent hearts after MI.

Results

73 miRNAs were up-regulated and 58 miRNAs were down-regulated significantly within the fetal infarct compared to remote cardiac samples. From adolescent hearts 69 non-redundant miRNAs were up-regulated and 63 miRNAs were down-regulated significantly in the infarct area compared to remote samples. Opposite differential expression profiles of 10 miRNAs within tissue regions (Infarct area, Border zone and Remote area of the left ventricle) occurred between the fetuses and adolescent sheep. These included miR-558 and miR-1538, which when suppressed using LNA anti-miRNAs in cell culture, increased cardiomyoblast proliferation.

Conclusion

There were significant differences in miRNA responses in fetal and adolescent sheep hearts following a MI, suggesting that the modulation of novel miRNA expression may have therapeutic potential, by promoting proliferation or repair in a damaged heart.

Differential microRNAs expression in calcified versus rheumatic aortic valve disease

BACKGROUND

The aortic valve (AV) is the most commonly affected valve in valvular heart diseases (VHDs). The objective of the study is to identify microRNA (miRNA) molecules expressed in VHDs and the differential expression patterns of miRNA in AVs with either calcification or rheumatism etiologies.

METHODS

Human AVs were collected during valve replacement surgery. RNA was extracted and miRNA containing libraries were prepared and sequenced using the next generation sequencing (NGS) approach. miRNAs identified as differentially expressed between the two etiologies were validated by quantitative real-time polymerase chain reaction (qPCR). The receiver operating characteristic (ROC) curve analysis was performed to examine the ability of relevant miRNA to differentiate between calcification and rheumatism etiologies.

RESULTS

Rheumatic and calcified AV samples were prepared for the NGS and were successfully sequenced. The expression was validated by the qPCR approach in 46 AVs, 13 rheumatic, and 33 calcified AVs, confirming that miR-145-5p, miR-199a-5p, and miR-5701 were significantly higher in rheumatic AVs as compared with calcified AVs. ROC curve analysis revealed that miR-145-5p had a sensitivity of 76.92% and a specificity of 94.12%, area under the curve (AUC) = 0.88 (P = .0001), and miR-5701 had a sensitivity of 84.62% and a specificity of 76.47%, AUC = 0.78 (P = .0001), whereas miR-199a-5p had a sensitivity of 84.62%, and a specificity of 57.58%, AUC = 0.73 (P = .0083).

CONCLUSION

We documented differential miRNA expression between AV disease etiologies. The miRNAs identified in this study advance our understanding of the mechanisms underlining AV disease.

Decrypting the crosstalk of noncoding RNAs in the progression of IPF

Idiopathic pulmonary fibrosis (IPF) is an agnogenic, rare, and lethal disease, with high mortality and poor prognosis and a median survival time as short as 3 to 5 years after diagnosis. No effective therapeutic drugs are still not available not only in clinical practice, but also in preclinical phases. To better and deeper understand pulmonary fibrosis will provide more effective strategies for therapy. Mounting evidence suggests that noncoding RNAs (ncRNAs) and their interactions may contribute to lung fibrosis; however, the mechanisms underlying their roles are largely unknown. In this review, we systematically summarized the recent advances regarding the crucial roles of long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) and crosstalk among them in the development of IPF. The perspective for related genes was well highlighted. In summary, ncRNA and their interactions play a key regulatory part in the progression of IPF and are bound to provide us with new diagnostic and therapeutic targets.

MicroRNA and Cardiovascular Diseases

Cardiovascular diseases are one of the most common causes of death in both developing and developed countries worldwide. Even though there have been improvements in primary prevention, the prevalence of cardiovascular diseases continues to increase in recent years. Hence, it is crucial to both investigate the molecular pathophysiology of cardiovascular diseases in-depth and find novel biomarkers regarding the early and proper prevention and diagnosis of these diseases. MicroRNAs, or miRNAs, are endogenous, conserved, single-stranded non-coding RNAs of 21-25 nucleotides in length. miRNAs have important roles in various cellular events such as embryogenesis, proliferation, vasculogenesis, apoptosis, cell growth, differentiation, and tumorigenesis. They also have potential roles in the cardiovascular system, including angiogenesis, cardiac cell contractility, control of lipid metabolism, plaque formation, the arrangement of cardiac rhythm, and cardiac cell growth. Circulating miRNAs are promising novel biomarkers for purposes of the diagnosis and prognosis of cardiovascular diseases. Cell or tissue specificity, stability in serum or plasma, resistance to degradative factors such as freeze-thaw cycles or enzymes in the blood, and fast-release kinetics, provide the potential for miRNAs to be surrogate markers for the early and accurate diagnosis of disease and for predicting middle- or long-term prognosis. Moreover, it may be a logical approach to combine miRNAs with traditional biomarkers to improve risk stratification and long-term prognosis. In addition to their efficacy in both diagnosis and prognosis, miRNA-based therapeutics may be beneficial for treating cardiovascular diseases using novel platforms and computational tools and in combination with traditional methods of analysis. microRNAs are promising, novel therapeutic agents, which can affect multiple genes using different signaling pathways. miRNAs therapeutic modulation techniques have been used in the settings of atherosclerosis, acute myocardial infarction, restenosis, vascular remodeling, arrhythmias, hypertrophy and fibrosis, angiogenesis and cardiogenesis, aortic aneurysm, pulmonary hypertension, and ischemic injury. This review presents detailed information about miRNAs regarding structure and biogenesis, stages of synthesis and functions, expression profiles in serum/plasma of living organisms, diagnostic and prognostic potential as novel biomarkers, and therapeutic applications in various diseases.

SR9009 administered for one day after myocardial ischemia-reperfusion prevents heart failure in mice by targeting the cardiac inflammasome

Reperfusion of patients after myocardial infarction (heart attack) triggers cardiac inflammation that leads to infarct expansion and heart failure (HF). We previously showed that the circadian mechanism is a critical regulator of reperfusion injury. However, whether pharmacological targeting using circadian medicine limits reperfusion injury and protects against HF is unknown. Here, we show that short-term targeting of the circadian driver REV-ERB with SR9009 benefits long-term cardiac repair post-myocardial ischemia reperfusion in mice. Gain and loss of function studies demonstrate specificity of targeting REV-ERB in mice. Treatment for just one day abates the cardiac NLRP3 inflammasome, decreasing immunocyte recruitment, and thereby allowing the vulnerable infarct to heal. Therapy is given in vivo, after reperfusion, and promotes efficient repair. This study presents downregulation of the cardiac inflammasome in fibroblasts as a cellular target of SR9009, inviting more targeted therapeutic investigations in the future.

Down-regulation of miRNA 145 and up-regulation of miRNA 4516 may be associated with primary hypertension

Complex mechanisms including genetic factors have been proposed in the pathogenesis of primary hypertension (HT). Micro RNAs (miRNAs) are single-stranded RNA molecules that are not converted into protein products. However, it has been established that genes regulate conversion into protein products. The primary aim of this study was to investigate the roles of miRNA 4516, miRNA 145, miRNA 24, and miRNA 181a in the pathogenesis of HT. The secondary aim was to investigate the relation between these miRNAs and renin, aldosterone, norepinephrine, renalase, and NOS. Fifty-two hypertensive and 51 control normotensive individuals under observation in the Cappadocia cohort were included in the study. miRNA 4516, miRNA 181a, miRNA 24, and miRNA 145 levels were measured using the ddPCR method. miRNA 4516 and norepinephrine levels were significantly higher in the HT group (P < .005 for both), while miRNA 145 levels were significantly lower (<.05). miRNA 4516 up-regulation (P < .05) and miRNA 145 down-regulation (P < .05) were identified as independent predictors of HT. Renalase exhibited negative correlation with miRNA 4516 and positive correlation with miRNA 145 in the patient and control group. In addition, negative correlation was present between miRNA 24 and NE and NOS and between miRNA 181a and NOS in the patient group. Our study identified, for the first time in the literature, miRNA 4516 up-regulation and miRNA 145 down-regulation as independent determinants of HT. Further studies performed in the light of our findings may lead to a better understanding of the pathogenesis and new therapeutic possibilities.

Enhancement of therapeutic potential of mesenchymal stem cell-derived extracellular vesicles

After the initial investigations into applications of mesenchymal stem cells (MSCs) for cell therapy, there was increased interest in their secreted soluble factors. Following studies of MSCs and their secreted factors, extracellular vesicles (EVs) released from MSCs have emerged as a new mode of intercellular crosstalk. MSC-derived EVs have been identified as essential signaling mediators under both physiological and pathological conditions, and they appear to be responsible for many of the therapeutic effects of MSCs. In several in vitro and in vivo models, EVs have been observed to have supportive functions in modulating the immune system, mainly mediated by EV-associated proteins and nucleic acids. Moreover, stimulation of MSCs with biophysical or biochemical cues, including EVs from other cells, has been shown to influence the contents and biological activities of subsequent MSC-derived EVs. This review provides on overview of the contents of MSC-derived EVs in terms of their supportive effects, and it provides different perspectives on the manipulation of MSCs to improve the secretion of EVs and subsequent EV-mediated activities. In this review, we discuss the possibilities for manipulating MSCs for EV-based cell therapy and for using EVs to affect the expression of elements of interest in MSCs. In this way, we provide a clear perspective on the state of the art of EVs in cell therapy focusing on MSCs, and we raise pertinent questions and suggestions for knowledge gaps to be filled.

Epigenetic and metabolic alterations in human amniotic fluid stem cells induced to cardiomyogenic differentiation by DNA methyltransferases and p53 inhibitors

Human amniotic fluid-derived mesenchymal stem cells (AF-MSCs) may be a valuable source for cell therapy and regenerative medicine. In this study, the potential of DNA methyltransferases (DNMT) inhibitors Decitabine, Zebularine, RG108 alone or combined with Zebularine and p53 inhibitor Pifithrin-α to induce cardiomyogenic differentiation of AF-MSCs was investigated. Differentiation into cardiomyocyte-like cells initiation was indicated with all agents by changes in the cell phenotype, upregulation of the relative expression of the main cardiac genes (NKX2-5, TNNT2, MYH6, and DES) as well as of cardiac ion channels genes (sodium, calcium, and potassium) as determined by reverse-transcription quantitative polymerase chain reaction and the increase in Connexin43 levels as detected from Western blot and immunofluorescence data. Cellular energetics and mitochondrial function in induced cells were assessed using Seahorse analyzer and revealed the initiation of AF-MSCs metabolic transformation into cardiomyocyte-like cells. All used inducers were nontoxic to AF-MSCs, arrested cell cycle at the G0/G1 phase, and upregulated p53 and p21 expression. The relative expression of miR-34a and miR-145 that are related to cell cycle regulation was also observed. Furthermore, the evaluated levels of chromatin remodeling proteins enhancer of zeste homolog 2, suppressor of zeste 12 protein homolog, DNMT1, histone deacetylase 1 (HDAC1), HDAC2, and heterochromatin protein 1α, as well as the rate of activating histone modifications, exhibited rearrangements of chromatin after the induction of cardiomyogenic differentiation. In conclusion, we demonstrated that all explored DNMT and p53 inhibitors initiated cardiomyogenesis-related alterations in AF-MSCs through rather similar mechanisms but to a different extent providing useful insights for the future research and potential applications of AF-MSCs.

Knockout of Canopy 2 activates p16INK4a pathway to impair cardiac repair

BACKGROUND

Cardiac repair depends on angiogenesis and cell proliferation. Previously we identified Canopy 2 (CNPY2) as a secreted angiogenic growth factor which promotes neovascularization. We investigated the role of CNPY2 in cardiac repair following myocardial infarction (MI) and the possible mediators involved using Cnpy2 knockout (KO) mice and human cardiac tissue.

METHODS AND RESULTS

Cardiac tissue from patients with end-stage heart failure had significantly lower endogenous CNPY2 expression compared to samples from control patients. CNPY2 expression in mouse hearts significantly decreased following MI. Significantly less leukocyte and endothelial cell proliferation was found in Cnpy2 KO than wild-type (WT) mice post MI which contributed to impaired angiogenesis, tissue repair, and decreased cardiac function (fractional shortening: WT: 21.1 ± 2.1% vs. KO: 16.4 ± 1.6%, p < .01 at day 28 post MI). RT-qPCR revealed significantly increased p16^INK4a expression in Cnpy2 KO mouse hearts (WT: 1.0 ± 0.04 vs. KO: 2.33 ± 0.11 [relative expression of p16 ^INK4a], p < .01) which was confirmed by immunostaining (WT: 8.47 ± 1.22 vs. KO: 12.9 ± 1.22 [% total cells], p < .05) for the p16^INK4a protein. Expression of cell cycle-related proteins, cyclin D1, cyclin-dependent kinases 4 and 6, and phosphorylated retinoblastoma protein (pRb) was significantly decreased in Cnpy2 KO mouse hearts. The up-regulation of the p16^INK4a/cyclin D1/Rb pathway by knockout of Cnpy2 was accompanied by attenuation of PDK1/Akt phosphorylation. MI exacerbated the detrimental effects of p16^INK4a on tissue repair in Cnpy2 KO mice. Overexpression of CNPY2 in the cardiac tissue of transgenic mice reversed the inhibition of cell proliferation through suppression of the p16^INK4a pathway.

CONCLUSIONS

Cardiac injury and progressive heart failure were associated with decreased CNPY2 levels in both humans and mice. Knockout of Cnpy2 resulted in up-regulation of p16^INK4a which impaired cardiac function and tissue repair. These data suggest that CNPY2 is an important regulator of p16^INK4a and promotes cell proliferation and tissue repair through inhibition of the p16^INK4a pathway. CNPY2 treatment may offer a new approach to restore cardiac function after an MI.

Inhibition of circHIPK3 prevents angiotensin II-induced cardiac fibrosis by sponging miR-29b-3p

BACKGROUND

Circular RNAs (circRNAs) are emerging as powerful regulators of cardiac development and disease. Nevertheless, detailed studies describing circRNA-mediated regulation of cardiac fibroblasts (CFs) biology and their role in cardiac fibrosis remain limited.

METHODS

PCR and Sanger sequencing were performed to identify the expression of circHIPK3 in CFs. Edu corporation assays, Transwell migration assays, and immunofluorescence staining assays were conducted to detect the function of circHIPK3 in CFs in vitro. Bioinformatics analysis, dual luciferase activity assays, RNA immunoprecipitation, and fluorescent in situ hybridization experiments were conducted to investigate the mechanism of circHIPK3-mediated cardiac fibrosis. Echocardiographic analysis, Sirius Red staining and immunofluorescence staining were performed to investigate the function of circHIPK3 in angiotensin II (Ang II) induced cardiac fibrosis in vivo.

RESULTS

circHIPK3 expression markedly increased in CFs and heart tissues after the treatment of Ang II. circHIPK3 silencing attenuates CFs proliferation, migration and the upregulation of a-SMA expression levels induced by Ang II in vitro. circHIPK3 acted as a miR-29b-3p sponge and overexpression of circHIPK3 effectively reverses miR-29b-3p-induced inhibition of CFs proliferation and migration and alters the expression levels of miR-29b-3p targeting genes (a-SMA, COL1A1, COL3A1) in vitro. Combination of circHIPK3 silencing and miR-29b-3p overexpression had a stronger effect on cardiac fibrosis suppression in vivo than did circHIPK3 silencing or miR-29b-3p overexpression alone.

CONCLUSIONS

Our data suggest that circHIPK3 serves as a miR-29b-3p sponge to regulate CF proliferation, migration and development of cardiac fibrosis, revealing a potential new target for the prevention of Ang II-induced cardiac fibrosis.

Circulating MiR-17-5p, MiR-126-5p and MiR-145-3p Are Novel Biomarkers for Diagnosis of Acute Myocardial Infarction

Ischemic heart disease including myocardial infarction (MI) is a major cause of mortality and morbidity worldwide. In order to manage the acute myocardial infarction (AMI) outbreaks, novel biomarkers for risk prediction are needed. Recent studies have shown that circulating microRNAs (miRNAs) are promising biomarkers for cardiovascular diseases prediction. This study aimed to determine the possibility of circulating miRNAs used as biomarkers for AMI. The dynamic expression levels of miRNAs were examined before and after percutaneous coronary intervention (PCI) in patients. Circulating miR-17-5p, miR-126-5p, and miR-145-3p were selected and validated in 29 patients with AMI and 21 matched controls by quantitative real-time PCR. The expression levels of plasma miR-17-5p, miR-126-5p, and miR-145-3p were significantly increased in AMI patients. Receiver Operating Characteristic (ROC) analysis indicated that miR-17-5p, miR-126-5p, and miR-145-3p showed considerable diagnostic efficiency for AMI. Furthermore, we demonstrated that the combination of these three miRNAs managed to provide more accurate diagnosing of AMI.

A miRNA-145/TGF-β1 negative feedback loop regulates the cancer-associated fibroblast phenotype

The dissemination of cancer cells to local and distant sites depends on a complex and poorly understood interplay between malignant cells and the cellular and non-cellular components surrounding them, collectively termed the tumour microenvironment. One of the most abundant cell types of the tumour microenvironment is the fibroblast, which becomes corrupted by locally derived cues such as TGF-β1 and acquires an altered, heterogeneous phenotype (cancer-associated fibroblasts, CAF) supportive of tumour cell invasion and metastasis. Efforts to develop new treatments targeting the tumour mesenchyme are hampered by a poor understanding of the mechanisms underlying the development of CAF. Here, we examine the contribution of microRNA to the development of experimentally-derived CAF and correlate this with changes observed in CAF derived from tumours. Exposure of primary normal human fibroblasts to TGF-β1 resulted in the acquisition of a myofibroblastic CAF-like phenotype. This was associated with increased expression of miR-145, a miRNA predicted in silico to target multiple components of the TGF-β signalling pathway. miR-145 was also overexpressed in CAF derived from oral cancers. Overexpression of miR-145 blocked TGF-β1-induced myofibroblastic differentiation and reverted CAF towards a normal fibroblast phenotype. We conclude that miR-145 is a key regulator of the CAF phenotype, acting in a negative feedback loop to dampen acquisition of myofibroblastic traits, a key feature of CAF associated with poor disease outcome.

miR-145-5p is associated with smoke-related chronic obstructive pulmonary disease via targeting KLF5

Increasing evidence illustrate that dysregulation of microRNAs (miRNAs) is involved in the pathogenesis of chronic obstructive pulmonary disease (COPD), which is mainly resulted from cigarette smoke (CS) exposure. However, the role of miR-145-5p in CS-mediated COPD remains largely unknown. Thus, the aim of this study was to investigate the expression level of miR-145-5p in 31 human lung tissues samples, and to explore its regulatory role in the apoptosis and inflammation of human bronchial epithelial cells (HBECs) following CS extract (CSE) exposure. We found that miR-145-5p was significantly down-regulated in lung tissues from smokers without or with COPD compared to non-smokers. Functional assays showed that miR-145-5p overexpression remarkably alleviated CSE-induced apoptosis and inflammation response by regulating p53-mediated apoptotic signaling and pre-inflammatory factors such as necrosis factor-α (TNF-α), interleukins (IL)-6, IL-8 in HBECs, whereas, down-regulation of miR-145-5p showed opposite effects. Furthermore, luciferase reporter assays verified that Kruppel-like 5 (KLF5) was a direct target of miR-145-5p. Western blot assay also confirmed that KLF5 was up-regulated in COPD tissues and was negatively associated with miR-145-5p expression. Restoration of miR-145-5p expression significantly abrogated the suppressive effect of miR-145-5p on CSE-stimulated apoptosis and inflammation. In addition, the CSE-induced NF-κB signaling activation was suppressed by miR-145-5p overexpression. Therefore, our data suggested that miR-145-5p conferred protection against CSE-induced airway epithelial cell apoptosis and inflammation partially via targeting KLF5, which might be a potential therapeutic biomarker in COPD treatment.

miR-145-5p affects the differentiation of gastric cancer by targeting KLF5 directly

Krüppel-like factor 5 (KLF5) takes part in the pathologic processes of many types of cancer; however, its expression and roles in the biological behavior of gastric cancer remain unknown. TargetScan suggested that miR-145-5p is the predicted effective and conserved microRNA (miRNA) that binds to KLF5 through its 3'-untranslated region (UTR). We investigated the expression of KLF5 and miR-145-5p messenger RNA (mRNA) in gastric cancer and then analyzed its role in the biological behavior of gastric cancer cells. Our results indicated that KLF5 expression was detected by immunohistochemistry in 39.7% of the gastric cancer cases and was increased compared with that of the corresponding noncancerous normal mucosa (0.01 < p < 0.05). The poorly differentiated subtype showed positive KLF5 expression, whereas the differentiated subtype showed negative KLF5 expression (p < 0.05). Dual-luciferase reporter assay suggested KLF5 3'-UTR was the direct target of miR-145-5p. Compared with the differentiated gastric cancer, miR-145-5p was downregulated in undifferentiated gastric cancer (p < 0.05). The downregulation of KLF5 expression and differentiation of MGC-803 and BGC-823 caused by siKLF5 or miR-145-5p mimic transfection. Our results indicated that miR-145-5p/KLF5 3'-UTR affected the differentiation of gastric cancer. miR-145-5p was able to promote gastric cancer differentiation by targeting KLF5 3'-UTR directly. Our data suggest a novel mechanism for cancer differentiation and a new facet to the role of miR-145-5p/KLF5 in gastric cancer.

Potential regulatory role of circular RNA in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive type of interstitial pneumonia with unknown causes, poor prognosis and no effective therapy available. Circular RNAs (circRNAs), which serve as potential therapeutic targets and diagnostic biomarkers for certain diseases, represent a recent hotspot in the field of RNA research. In the present study, a total of 67 significantly dysregulated circRNAs were identified in the plasma of IPF patients by using a circRNA microarray. Among these circRNAs, 38 were upregulated, whereas 29 were downregulated. Further validation of the results by polymerase chain reaction analysis indicated that Homo sapiens (hsa)_circRNA_100906, hsa_circRNA_102100 and hsa_circRNA_102348 were significantly upregulated, whereas hsa_circRNA_101225, hsa_circRNA_104780 and hsa_circRNA_101242 were downregulated in plasma samples of IPF patients compared with those in samples from healthy controls. The majority of differentially expressed circRNAs were generated from exonic regions. The host genes of the differentially expressed circRNAs were involved in the regulation of the cell cycle, adherens junctions and RNA transport. The competing endogenous RNA (ceRNA) network of the circRNAs/micro(mi)RNAs/mRNAs indicated that circRNA-protected mRNA participated in transforming growth factor-β1, hypoxia-inducible factor-1, Wnt, Janus kinase, Rho-associated protein kinase, vascular endothelial growth factor, mitogen-activated protein kinase, Hedgehog and nuclear factor κB signalling pathways or functioned as biomarkers for pulmonary fibrosis. Furthermore, luciferase reporter assays confirmed that hsa_circRNA_100906 and hsa_circRNA_102348 directly interact with miR-324-5p and miR-630, respectively, which were downregulated in IPF patients. The present study provided a novel avenue for exploring the underlying molecular mechanisms of IPF disease.

Long Noncoding RNAs and Cardiac Disease

SIGNIFICANCE

To maintain homeostasis, gene expression has to be tightly regulated by complex and multiple mechanisms occurring at the epigenetic, transcriptional, and post-transcriptional levels. One crucial regulatory component is represented by long noncoding RNAs (lncRNAs), nonprotein-coding RNA species implicated in all of these levels. Thus, lncRNAs have been associated with any given process or pathway of interest in a variety of systems, including the heart. Recent Advances: Mounting evidence implicates lncRNAs in cardiovascular diseases (CVD) and progression and their presence in the blood of heart disease patients indicates that they are attractive potential biomarkers.

CRITICAL ISSUES

Our understanding of the regulation and molecular mechanisms of action of most lncRNAs remains rudimentary. A challenge is represented by their often low evolutionary sequence conservation that limits the use of animal models for preclinical studies. Nevertheless, a growing number of lncRNAs with an impact on heart function is rapidly accumulating. In this study, we will discuss (i) lncRNAs that control heart homeostasis and disease; (ii) concepts, approaches, and methodologies necessary to study lncRNAs in the heart; and (iii) challenges posed and opportunities presented by lncRNAs as potential therapeutic targets and biomarkers.

FUTURE DIRECTIONS

A deeper knowledge of the molecular mechanisms underpinning CVDs is necessary to develop more effective treatments. Further studies are needed to clarify the regulation and function of lncRNAs in the heart before they can be considered as therapeutic targets and disease biomarkers. Antioxid. Redox Signal. 29, 880-901.

Conditional and interaction gene-set analysis reveals novel functional pathways for blood pressure

Gene-set analysis provides insight into which functional and biological properties of genes are aetiologically relevant for a particular phenotype. But genes have multiple properties, and these properties are often correlated across genes. This can cause confounding in a gene-set analysis, because one property may be statistically associated even if biologically irrelevant to the phenotype, by being correlated with gene properties that are relevant. To address this issue we present a novel conditional and interaction gene-set analysis approach, which attains considerable functional refinement of its conclusions compared to traditional gene-set analysis. We applied our approach to blood pressure phenotypes in the UK Biobank data (N = 360,243), the results of which we report here. We confirm and further refine several associations with multiple processes involved in heart and blood vessel formation but also identify novel interactions, among others with cardiovascular tissues involved in regulatory pathways of blood pressure homoeostasis.

Gene-set analysis (GSA) is widely used to infer functional and biological properties of a gene set. Here, the authors develop a conditional and interaction gene-set analysis approach that can considerably refine results from traditional GSA.

Epigenetic Regulation of Myofibroblast Phenotypes in Fibrosis

Purpose of Review

Myofibroblasts are the fundamental drivers of fibrosing disorders; there is great value in better defining epigenetic networks involved in myofibroblast behavior. Complex epigenetic paradigms, which are likely organ and/or disease specific, direct pathologic myofibroblast phenotypes. In this review, we highlight epigenetic regulators and the mechanisms through which they shape myofibroblast phenotype in fibrotic diseases of different organs.

Recent Findings

Hundreds of genes and their expression contribute to the myofibroblast transcriptional regime influencing myofibroblast phenotype. An increasingly large number of epigenetic modifications have been identified in the regulation of these signaling pathways driving myofibroblast activation and disease progression. Drugs that inhibit or reverse profibrotic epigenetic modifications have shown promise in vitro and in vivo; however, no current epigenetic therapies have been approved to treat fibrosis. Newly described epigenetic mechanisms will be mentioned, along with potential therapeutic targets and innovative strategies to further understand myofibroblast-directed fibrosis.

Summary

Epigenetic regulators that direct myofibroblast behavior and differentiation into pathologic myofibroblast phenotypes in fibrotic disorders comprise both overlapping and organ-specific epigenetic mechanisms.

MicroRNA-145 Antagonism Reverses TGF-β Inhibition of F508del CFTR Correction in Airway Epithelia

RATIONALE

MicroRNAs (miRNAs) destabilize mRNA transcripts and inhibit protein translation. miR-145 is of particular interest in cystic fibrosis (CF) as it has a direct binding site in the 3'-untranslated region of CFTR (cystic fibrosis transmembrane conductance regulator) and is upregulated by the CF genetic modifier TGF (transforming growth factor)-β.

OBJECTIVES

To demonstrate that miR-145 mediates TGF-β inhibition of CFTR synthesis and function in airway epithelia.

METHODS

Primary human CF (F508del homozygous) and non-CF airway epithelial cells were grown to terminal differentiation at the air-liquid interface on permeable supports. TGF-β (5 ng/ml), a miR-145 mimic (20 nM), and a miR-145 antagonist (20 nM) were used to manipulate CFTR function. In CF cells, lumacaftor (3 μM) and ivacaftor (10 μM) corrected mutant F508del CFTR. Quantification of CFTR mRNA, protein, and function was done by standard techniques.

MEASUREMENTS AND MAIN RESULTS

miR-145 is increased fourfold in CF BAL fluid compared with non-CF (P < 0.01) and increased 10-fold in CF primary airway epithelial cells (P < 0.01). Exogenous TGF-β doubles miR-145 expression (P < 0.05), halves wild-type CFTR mRNA and protein levels (P < 0.01), and nullifies lumacaftor/ivacaftor F508del CFTR correction. miR-145 overexpression similarly decreases wild-type CFTR protein synthesis (P < 0.01) and function (P < 0.05), and eliminates F508del corrector benefit. miR-145 antagonism blocks TGF-β suppression of CFTR and enhances lumacaftor correction of F508del CFTR.

CONCLUSIONS

miR-145 mediates TGF-β inhibition of CFTR synthesis and function in airway epithelia. Specific antagonists to miR-145 interrupt TGF-β signaling to restore F508del CFTR modulation. miR-145 antagonism may offer a novel therapeutic opportunity to enhance therapeutic benefit of F508del CFTR correction in CF epithelia.

miRNA-145 is associated with spontaneous hypertension by targeting SLC7A1

Previous studies have indicated that microRNAs (miRNAs/miRs) may participate in the pathogenesis of hypertension. miR-145 has been demonstrated to serve important roles in the development of numerous cardiovascular diseases. However, the specific role of miR-145 in hypertension remains unclear. The present study aimed to investigate the role of miR-145 in spontaneously hypertensive rats (SHR) and rat vascular endothelial cells (RVECs). The results of the present study demonstrated that in the SHR group miR-145 expression was significantly upregulated in the thoracic aorta compared with the control group. Furthermore, a significant decrease in nitric oxide (NO) content was observed in the SHR group compared with the control rats. In RVECs, silencing miR-145 induced a significant increase in the expression of solute carrier family 7 member 1 (SLC7A1) and phosphorylated endothelial nitric oxide synthase, and a dual-luciferase reporter assay confirmed that SLC7A1 is a direct target of miR-145. The results of the present study indicate that miR-145 functions as a key mediator in the pathogenesis of hypertension via targeting SLC7A1, which suggests that miR-145 is a potential target for the treatment of hypertension.

miR-145 promoted anoikis resistance in tumor endothelial cells

Tumor progression is dependent on tumor angiogenesis. We previously reported that the phenotype of tumor endothelial cells (TECs) is distinct from normal endothelial cells (NECs). Herein, we conducted a pathway analysis using a public TEC microarray database and identified several putative TEC-specific miRNAs. We found that miR-145 expression was upregulated in TECs and that miR-145 enhanced cell adhesion and anoikis resistance and upregulated Bcl-2 and Bcl-xl via ERK1/2 in human microvascular endothelial cells. These findings suggested that miR-145 is involved in the acquisition of the TEC phenotype, partially. Therefore, miR-145 and its target genes may be molecular targets for anti-angiogenic therapy.

Significant contribution of TRPC6 channel-mediated Ca2+ influx to the pathogenesis of Crohn's disease fibrotic stenosis

Intestinal fibrosis is an intractable complication of Crohn's disease (CD), and, when occurring excessively, causes severe intestinal obstruction that often necessitates surgical resection. The fibrosis is characterized by an imbalance in the turnover of extracellular matrix (ECM) components, where intestinal fibroblasts/myofibroblasts play active roles in ECM production, fibrogenesis and tissue remodeling, which eventually leads to the formation of stenotic lesions. There is however a great paucity of knowledge about how intestinal fibrosis initiates and progresses, which hampers the development of effective pharmacotherapies against CD. Recently, we explored the potential implications of transient receptor potential (TRP) channels in the pathogenesis of intestinal fibrosis, since they are known to act as cellular stress sensors/transducers affecting intracellular Ca²⁺ homeostasis/dynamics, and are involved in a broad spectrum of cell pathophysiology including inflammation and tissue remodeling. In this review, we will place a particular emphasis on the intestinal fibroblast/myofibroblast TRPC6 channel to discuss its modulatory effects on fibrotic responses and therapeutic potential for anti-fibrotic treatment against CD-related stenosis.

Maintenance of the contractile phenotype in corpus cavernosum smooth muscle cells by Myocardin gene therapy ameliorates erectile dysfunction in bilateral cavernous nerve injury rats

The pathophysiology of erectile dysfunction post radical prostatectomy is not clearly clarified, and the low efficacy of traditional PDE5i treatment remains a major complaint in contemporary practice. This study aimed to demonstrate phenotypic modulation in bilateral cavernous nerve injury (BCNI) rats within 7 days, and subsequently validate gene therapy with Myocardin (Mycod) by maintaining a contractile phenotype in corpus cavernosum smooth muscle cells. Initially, 36 male rats were randomly divided into BCNI and negative control (NC) groups for histological and phenotypic molecular measurements at 3, 5, and 7 days. Afterwards, an additional 30 rats received a single intra-cavernous injection of 50 μL PBS, Ad-Myocd (1 × 1011  pfu/ml) or Ad-vector for 10 animals each, namely the NC+PBS, BCNI+Ad-Myocd, and BCNI+Ad-vector groups. Finally, the validity and mechanism of Myocd transfection was explored at 21 days in vivo and 48 h in vitro. Western blotting showed canonical declines in Myocd, α-SMA, and Calponin expression, as well as elevated Osteopontin (OPN) expression, before corporeal morphological and SM-to-collagen ratio changes at day 5 after injury. Overexpression of Myocd maintained the contractile phenotype of corpus cavernosum smooth muscle cells, ameliorated bilateral cavernous nerve injury rat erectile dysfunction, as well as promoted cell contractility and suppressed proliferative capacity. Simultaneously, confocal imaging revealed up-regulation and co-localization of serum response factor in gene-transferred cells. In conclusion, our study is the first to investigate corpus cavernosum smooth muscle cells phenotypes in the early stages of cavernous injury model rats, and Myocd reversed phenotypic modulation by activating serum response factor. The experimental results demonstrated the validity of gene therapy for erectile dysfunction.

Aspirin alleviates cardiac fibrosis in mice by inhibiting autophagy

Aspirin (ASA) is a cardioprotective drug with anti-cardiac fibrosis action in vivo. This study was aimed to clarify the anti-cardiac fibrosis action of ASA and the underlying mechanisms. Two heart injury models (injection of isoproterenol and ligation of the left anterior descending branch) were used in mice to induce cardiac fibrosis. The animals were treated with ASA (10 mg·kg^-1·d^-1, ig) for 21 and 14 d, respectively. ASA administration significantly improved cardiac function, and ameliorated heart damage and fibrosis in the mice. The mechanisms underlying ASA's anti-fibrotic effect were further analyzed in neonatal cardiac fibroblasts (CFs) exposed to hypoxia in vitro. ASA (0.5-5 mmol/L) dose-dependently inhibited the proliferation and Akt phosphorylation in the CFs. In addition, ASA significantly inhibited CF apoptosis, and decreased the levels of apoptosis markers (cleaved caspase 3 and Parp1), which might serve as a side effect of anti-fibrotic effect of ASA. Furthermore, ASA dose-dependently inhibited the autophagy in the CFs, as evidenced by the reduced levels of autophagy marker LC3-II. The autophagy inhibitor Pepstatin A (PepA) promoted the inhibitory effect of ASA on CF proliferation, whereas the autophagy inducer rapamycin rescued ASA-caused inhibition of CF proliferation, suggesting an autophagy-dependent anti-proliferative effect of ASA. Both p38 inhibitor SB203580 and ROS scavenger N-acetyl-cysteine (NAC) significantly decreased Akt phosphorylation in CFs in the basal and hypoxic situations, but they both significantly increased LC3-II levels in the CFs. Our results suggest that an autophagy- and p38/ROS-dependent pathway mediates the anti-cardiac fibrosis effect of ASA in CFs. As PepA and SB203580 did not affect ASA-caused inhibition of CF apoptosis, the drug combination will enhance ASA's therapeutic effects.

Differential MicroRNA Expression Profile of Human Embryonic Stem Cell-Derived Cardiac Lineage Cells

MicroRNAs (miRNAs) are small non-coding RNA molecules that participate in transcriptional and post-transcriptional regulation of gene expression. miRNAs have numerous roles in cellular function including embryonic development. Human embryonic stem cells (hESCs) are capable of self-renewal and can differentiate into most of cell types including cardiomyocytes (CMs). These characteristics of hESCs make them considered as an important model for studying human embryonic development and tissue specific differentiation. In this study, we tried to demonstrate the profile of miRNA expression in cardiac differentiation from hESCs. To induce differentiation, we differentiated hESCs into CMs by direct differentiation method and characterized differentiated cells. To analyze the expression of miRNAs, we distinguished (days 4, 8, 12, 16, 20, 24, 28) and isolated RNAs from each differentiation stage. miRNA specific RT-qPCR was performed and the expression profile of miR-1, -30d, -133a, -143, -145, -378a, -499a was evaluated. The expression of all miRs was up-regulated at day 8. miR-143 and -145 expression was also up-regulated at the later stage of differentiation. Only miR-378a expression returned to undifferentiated hESC levels at the other stages of differentiation. In conclusion, we elucidated the expression profile of miRNAs during differentiation into cardiomyocytes from hESCs. Our findings demonstrate the expression of miRNAs was stage-dependent during differentiation and suggest that the differentiation into CMs can be regulated by miRNAs through direct or indirect pathway.