H19 Induces Abdominal Aortic Aneurysm Development and Progression

LncRNA H19 regulates smooth muscle cell functions and participates in the development of aortic dissection through sponging miR-193b-3p

BACKGROUND

Multiple studies showed that long-chain noncoding RNA H19 (LncRNA H19) is high-expressed in human and mouse abdominal aortic aneurysms (AAAs). We speculated that it plays an important role in arterial disease, and therefore studied the role and mechanism of H19 in aortic dissection (AD).

METHODS

The expressions of related genes in human aortic smooth muscle cells (HASMCs) induced by platelet-derived growth factor BB (PDGF-BB) or in the aortic tissue of AD patients/mice were identified by Western blot and quantitative real-time polymerase chain reaction. The targeting relationship between H19 and miR-193b-3p was predicted and verified by bioinformatics analysis, dual luciferase assay, RNA pull-down assay, RNA immunoprecipitation (RIP), and Pearson correlation coefficient. The H19 and miR-193b-3p effects on the biological functions of tissues and cells were examined by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, thiazolyl blue tetrazolium bromide) assay, wound-healing assay, and Hematoxylin-Eosin (HE) staining.

RESULTS

LncRNA H19 was abnormally high-expressed in thoracic aorta tissues of AD patients, and it could competitively bind to and inhibit miR-193b-3p. In the PDGF-BB group, the expressions of H19, matrix metallopeptidase (MMP) 2 (MMP-2) and MMP-9 were up-regulated and the expressions of miR-193b-3p, α-SMA, and SM22α were down-regulated; moreover, the proliferation and migration rate of HASMCs were increased. However, H19 silencing reversed the regulation of PDGF-BB on HASMCs. More interestingly, miR-193b-3p inhibitor could partially reverse the effect of H19 silencing. In addition, the above results were verified by animal experiments, showing that shH19 and up-regulated miR-193b-3p could significantly reduce the thoracic aorta pathological damage in AD mice.

CONCLUSION

LncRNA H19 regulated smooth muscle cell function by sponging miR-193b-3p and it participated in the development of AD.

P-Selectin Glycoprotein Ligand-1 Deficiency Protects Against Aortic Aneurysm Formation Induced by DOCA Plus Salt

PURPOSE

P-selectin glycoprotein ligand-1 (PSGL-1) acts as a crucial regulator for the inflammatory cells infiltration by mediating the adhesion of leukocytes. However, the role of PSGL-1 in aortic aneurysm remains elusive. Here, we investigated the role of PSGL-1 in aortic aneurysm (AA) development.

METHODS

We first detected PSGL-1 expression in samples from aortic aneurysm patients and mouse AA models via western blotting, immunofluorescence, and flow cytometry, and then we used global PSGL-1 knockout mice and their wild type controls to establish an aortic aneurysm model induced by deoxycorticosterone acetate (DOCA) plus high salt (HS). The incidence, fatality rates, and the pathological changes of aortic aneurysm were analyzed in each group. The inflammation, adhesion molecules expression, and PSGL-1 mediated leukocyte-endothelial adhesion and their underlying mechanisms were explored further.

RESULTS

Increased PSGL-1 levels were observed in human and mouse aortic aneurysm, and on leukocytes of mice treated with DOCA+HS. PSGL-1 deficiency reduced the incidence and severity of aortic aneurysm significantly, as well as decreased elastin fragmentation, collagen accumulation, and smooth muscle cells degeneration. Mechanistically, the protective effect of PSGL-1 inhibition was mediated by the reduced adhesion molecules, and the subsequently reduced leukocyte-endothelial adhesion through the NF-κB pathway, which finally led to reduced inflammatory cells infiltration and decreased inflammatory factors expression.

CONCLUSION

PSGL-1 deficiency is protective against inflammatory cells migration and recruitment in the condition of AA through attenuation of leukocyte-endothelial adhesion. Inhibition of PSGL-1 may be a potential therapeutic target for the prevention and treatment of human AA.

Iron deficiency promotes aortic medial degeneration via destructing cytoskeleton of vascular smooth muscle cells

BACKGROUND

Aortic dissection (AD) and aortic aneurysm (AA) are critical illnesses with an unclear pathogenetic mechanism that seriously threaten human life. Aortic medial degeneration (AMD) is the main pathological feature of AD and AA. Diseases of iron metabolism can cause a variety of physiological dysfunctions. In this study, we aimed to clarify the state of iron metabolism in patients with AD and AA, and to explore the effect of iron metabolism on AMD.

METHODS

A total of 200 patients with AD or AA, and 60 patients with hypertension were included in the study. Blood samples were drawn immediately when patients were admitted to the hospital. Aortic specimens from patients with Stanford type A AD were obtained at the time of surgery. The status of iron metabolism in the circulation and the aortic wall was analyzed. In addition, apolipoprotein E knockout mice were fed chow with a different iron content, and angiotensin II (Ang II) was used to induce AMD. Furthermore, transferrin receptor 1 knockout (TFR1-/-) mice were used to study the effects of iron deficiency (ID) on aortic development, to observe the effects of different iron metabolism status on the formation of AMD in mice, and to explore the cytoskeleton of vascular smooth muscle cells (VSMCs) under different iron metabolism.

RESULTS

Patients with AMD were iron deficient. ID is associated with the development of AMD in hypertensive patients. Iron-deficient feeding combined with Ang II pumping promoted the formation of AMD and significantly shortened the survival time of mice. ID significantly impaired the cytoskeleton of VSMCs.

CONCLUSIONS

Our results highlighted that ID was associated with the formation of AMD in patients with hypertension. In this study, we identified a novel mechanism behind VSMCs dysfunction that was induced by ID, thereby suggesting iron homeostasis as a future precaution in patients with hypertension based on its important role in the maintenance of VSMC function.

Identification of Novel Long Noncoding RNAs and Their Role in Abdominal Aortic Aneurysm

Objective

Long noncoding RNAs (lncRNAs) have emerged as critical molecular regulators in various diseases. However, the potential regulatory role of lncRNAs in the pathogenesis of abdominal aortic aneurysm (AAA) remains elusive. The aim of this study was to identify crucial lncRNAs associated with human AAA by comparing the lncRNA and mRNA expression profiles of patients with AAA with those of control individuals.

Materials and Methods

The expression profiles of lncRNAs and mRNAs were analyzed in five dilated aortic samples from AAA patients and three normal aortic samples from control individuals using microarray technology. Functional annotation of the screened lncRNAs based on the differentially expressed genes was performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses.

Results

Microarray results revealed 2046 lncRNAs and 1363 mRNAs. Functional enrichment analysis showed that the mRNAs significantly associated with AAA were enriched in the NOD-like receptor (NLR) and nuclear factor kappa-B (NF-κB) signaling pathways and in cell adhesion molecules (CAMs), which are closely associated with pathophysiological changes in AAA. The lncRNAs identified using microarray analysis were further validated using quantitative real-time polymerase chain reaction (qRT-PCR) analysis with 12 versus 11 aortic samples. Finally, three key lncRNAs (ENST00000566954, ENST00000580897, and T181556) were confirmed using strict validation. A coding-noncoding coexpression (CNC) network and a competing endogenous RNA (ceRNA) network were constructed to determine the interaction among the lncRNAs, microRNAs, and mRNAs based on the confirmed lncRNAs.

Conclusions

Our microarray profiling analysis and validation of significantly expressed lncRNAs between patients with AAA and control group individuals may provide new diagnostic biomarkers for AAA. The underlying regulatory mechanisms of the confirmed lncRNAs in AAA pathogenesis need to be determined using in vitro and in vivo experiments.

Functional non-coding RNAs in vascular diseases

Recently, advances in genomic technology such as RNA sequencing and genome‐wide profiling have enabled the identification of considerable numbers of non‐coding RNAs (ncRNAs). MicroRNAs have been studied for decades, leading to the identification of those with disease‐causing and/or protective effects in vascular disease. Although other ncRNAs such as long ncRNAs have not been fully described yet, recent studies have indicated their important functions in the development of vascular diseases. Here, we summarize the current understanding of the mechanisms and functions of ncRNAs, focusing on microRNAs, circular RNAs and long ncRNAs in vascular diseases.

Icariin attenuates endothelial-mesenchymal transition via H19/miR-148b-3p/ELF5 in ox-LDL-stimulated HUVECs

Atherosclerosis is the main cause of cardio-cerebrovascular diseases. Endothelial-mesenchymal transition plays an important role in atherosclerosis. Icariin has a protective effect on atherosclerosis; however, the underlying mechanism remains unclear. In this study, we explored the molecular mechanism underlying the protective function of icariin in oxidized low-density lipoprotein-stimulated human umbilical vein endothelial cells. H19, a long non-coding RNA, was identified to be downregulated in the background of the oxidized low-density lipoprotein-induced endothelial-mesenchymal transition in human umbilical vein endothelial cells. Icariin upregulated H19 expression and inhibited the transformation of endothelial cells into interstitial cells. Overexpression of H19 affected endothelial-mesenchymal transition in oxidized low-density lipoprotein-stimulated human umbilical vein endothelial cells, whereas H19 knockdown reversed endothelial protective effects of icariin and reduced human umbilical vein endothelial cell migration. Knockdown of H19 significantly downregulated oxidized low-density lipoprotein-induced E74-like factor 5 and upregulated miR-148b-3p, which was reversed by icariin. Thus, icariin may play a protective role in atherosclerosis, and H19 may be a potential therapeutic target.

Biomarkers for Heart Failure Prognosis: Proteins, Genetic Scores and Non-coding RNAs

Heart failure (HF) is a complex disease in which cardiomyocyte injury leads to a cascade of inflammatory and fibrosis pathway activation, thereby causing decrease in cardiac function. As a result, several biomolecules are released which can be identified easily in circulating body fluids. The complex biological processes involved in the development and worsening of HF require an early treatment strategy to stop deterioration of cardiac function. Circulating biomarkers provide not only an ideal platform to detect subclinical changes, their clinical application also offers the opportunity to monitor disease treatment. Many of these biomarkers can be quantified with high sensitivity; allowing their clinical application to be evaluated beyond diagnostic purposes as potential tools for HF prognosis. Though the field of biomarkers is dominated by protein molecules, non-coding RNAs (microRNAs, long non-coding RNAs, and circular RNAs) are novel and promising biomarker candidates that encompass several ideal characteristics required in the biomarker field. The application of genetic biomarkers as genetic risk scores in disease prognosis, albeit in its infancy, holds promise to improve disease risk estimation. Despite the multitude of biomarkers that have been available and identified, the majority of novel biomarker candidates are not cardiac-specific, and instead may simply be a readout of systemic inflammation or other pathological processes. Thus, the true value of novel biomarker candidates in HF prognostication remains unclear. In this article, we discuss the current state of application of protein, genetic as well as non-coding RNA biomarkers in HF risk prognosis.

The role of non-coding RNA network in atherosclerosis

Atherosclerosis is the primary culprit of cardiovascular and cerebrovascular diseases. Also, atherogenesis and the development of atherosclerosis involve endothelial cells, monocytes/macrophages, smooth myocytes, and others. Increasingly, studies have found that non-coding RNA (ncRNA) which can regulate apoptosis, pyroptosis, autophagy, proliferation, and monocyte migration participates in atherogenesis and progress of atherosclerosis by the above. The ncRNA networks may be essential in regulating the complicated process of atherosclerosis. Accordingly, this review delves into the regulatory roles of ncRNA, which were introduced previously. The answer above is particularly crucial to explain further the regulatory mechanism of ncRNA in cardiovascular disorders. Furthermore, we discuss the possibility and related research of ncRNAs as a biomarker and therapeutic target for the prevention, diagnosis, and treatment of atherosclerosis.

Cell senescence: basic mechanisms and the need for computational networks in vascular ageing

This review seeks to provide an update of the mechanisms of vascular cell senescence, from newly identified molecules to arterial ageing phenotypes, and finally to present a computational approach to connect these selected proteins in biological networks. We will discuss current key signalling and gene expression pathways by which these focus proteins and networks drive normal and accelerated vascular ageing. We also review the possibility that senolytic drugs, designed to restore normal cell differentiation and function, could effectively treat multiple age-related vascular diseases. Finally, we discuss how cell senescence is both a cause and a consequence of vascular ageing because of the possible feedback controls between identified networks.

Long noncoding RNAs: Important participants and potential therapeutic targets for myocardial ischaemia reperfusion injury

Myocardial ischaemia reperfusion (I/R) injury is one of the leading causes of coronary artery disease-associated morbidity and mortality. While different strategies have been used to limit I/R injuries, cardiac functions often do not recover to the normal level as anticipated. Recent studies have pointed to important roles of long noncoding RNAs (lncRNAs) in the development of myocardial I/R injury. LncRNA is a class of RNA molecules of more than 200 nucleotides in length which are not translated into proteins. I/R causes dysregulation of lncRNA expression in cardiomyocytes, thereby affecting multiple cellular functions including mitochondrial homeostasis, apoptosis, necrosis and autophagy, suggesting that manipulating lncRNAs may be of great potential in counteracting I/R injury-induced myocardial dysfunctions. In this review, we provide an updated summary on our knowledge about contributions of lncRNAs to the development of I/R injury, with an emphasis on the functional links between several well established cardiac lncRNAs and regulation of cellular outcomes post I/R.

Exaggerated Autophagy in Stanford Type A Aortic Dissection: A Transcriptome Pilot Analysis of Human Ascending Aortic Tissues

Stanford type A aortic dissection (TAAD) is one of the most dangerous diseases of acute aortic syndrome. Molecular pathological studies on TAAD can aid in understanding the disease comprehensively and can provide insights into new diagnostic markers and potential therapeutic targets. In this study, we defined the molecular pathology of TAAD by performing transcriptome sequencing of human ascending aortic tissues. Pathway analysis revealed that activated inflammation, cell death and smooth muscle cell degeneration are the main pathological changes in aortic dissection. However, autophagy is considered to be one of the most important biological processes, regulating inflammatory reactions and degenerative changes. Therefore, we focused on the pathological role of autophagy in aortic dissection and identified 10 autophagy-regulated hub genes, which are all upregulated in TAAD. These results indicate that exaggerated autophagy participates in the pathological process of aortic dissection and may provide new insight for further basic research on TAAD.

Long noncoding RNA RP11-757G1.5 sponges miR-139-5p and upregulates YAP1 thereby promoting the proliferation and liver, spleen metastasis of colorectal cancer

BACKGROUND

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) acting as crucial regulators in tumorigenesis. However, its biological functions of lncRNAs in colorectal cancer (CRC) have not been systematically clarified.

METHODS

An unbiased screening was performed to identify disregulated lncRNAs revealed to be implicated in CRC carcinogenesis according to an online-available data dataset. In situ hybridization (ISH), RT-qPCR and RNA fluorescence in situ hybridization (RNA-FISH) were applied to detect RP11-757G1.5 expression in CRC tissues and cell lines. The associations of RP11-757G1.5 with clinicopathological characteristics were analyzed. Their effects on prognosis were analyzed by the Kaplan-Meier analysis, Log-rank test, Univariate and Multivariate Cox regression analysis. The potential biological function of RP11-757G1.5 in CRC was investigated by Colony formation, Edu cell proliferation, Flow cytometry, Wound healing and Transwell assays. Bioinformatics binding site analysis, Luciferase reporter assay, Ago2 immunoprecipitation assays, RNA pull-down assay, RT-qPCR and Western blotting were utilized to demonstrate the mechanism of RP11-757G1.5 acts as a molecular sponge of miR-139-5p to regulate the expression of YAP1. Finally, we further explore the potential role of RP11-757G1.5 in CRC orthotopic xenografts in vivo.

RESULTS

We discovered a novel oncogenic lncRNA RP11-757G1.5, that was overexpressed in CRC tissues, especially in aggressive cases. Moreover, up-regulation of RP11-757G1.5 strongly correlated with poor clinical outcomes of patients with CRC. Functional analyses revealed that RP11-757G1.5 promoted cell proliferation in vitro and in vivo. Furthermore, RP11-757G1.5 stimulated cell migration and invasion in vitro and in vivo. Mechanistic studies illustrated that RP11-757G1.5 regulated the expression of YAP1 through sponging miR-139-5p and inhibiting its activity thereby promoting CRC progression and development.

CONCLUSIONS

Altogether, these results reveal a novel RP11-757G1.5/miR-139-5p/YAP1 regulatory axis that participates in CRC carcinogenesis and progression.

Long non-coding RNA TCONS_00000200 as a non-invasive biomarker in patients with intracranial aneurysm

We performed long non-coding RNA (lncRNA) microarray assay to identify lncRNAs with differential expression between patients with intracranial aneurysm (IA) and healthy control individuals to evaluate their potential use as biomarkers of IA. Arraystar Human lncRNA Microarray v3.0 was performed to identify differentially expressed lncRNAs and mRNAs in plasma samples (4 ml). lncRNAs with the most pronounced differential expression were used to select gene markers, and results were validated by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Plasma levels of TCONS_00000200 (fold change: 2.28) and ENST00000511927 (fold change: 2.50) were significantly higher in IA patients than in healthy individuals (P<0.001), and plasma levels of ENST00000421997 (fold change: 0.45) and ENST00000538202 (fold change: 0.43) were significantly lower in IA patients than in healthy individuals (P<0.001). qRT-PCR confirmed the same trends of up- and down-regulation of these four lncRNAs. A receiver operating characteristic (ROC) curve for TCONS_00000200 showed that the area under the curve (AUC) was 0.963 (95% confidence interval, 0.919–1.000), optimal cut-off point was 0.0081, sensitivity was 90.0%, and specificity was 96.7%. These results indicate that the lncRNA TCONS_00000200 is differentially expressed in the plasma of IA patients and could serve as a biomarker of IA.

Role of epigenetic mechanisms regulated by enhancers and long noncoding RNAs in cardiovascular disease

PURPOSE OF REVIEW

Hyperlipidemia, hypertension, diabetes and related metabolic disorders increase the risk for cardiovascular disease (CVD). Despite significant progress in the identification of key mechanisms and genetic polymorphisms linked to various CVDs, the rates of CVDs continue to escalate, underscoring the need to evaluate additional mechanisms for more effective therapies. Environment and lifestyle changes can alter epigenetic mechanisms mediated by histone modifications and long noncoding RNAs (lncRNAs) which play important roles in gene regulation. The review summarizes recent findings on the role of epigenetic mechanisms in CVD.

RECENT FINDINGS

Recent studies identified dysregulated histone modifications and chromatin modifying proteins at cis-regulatory elements, including enhancers/super-enhancers, mediating the expression of genes associated with CVD in vascular and immune cells in response to growth factors and inflammatory mediators. Several lncRNAs have also been reported to contribute to pathological gene expression via cis and trans mechanisms involving interactions with nuclear proteins, co-operation with enhancers/super enhancers and acting as microRNA sponges.

SUMMARY

Epigenomic approaches in cells affected in CVDs can be exploited to understand the function of genetic polymorphisms at cis-regulatory elements and crosstalk between enhancers and lncRNAs associated with disease susceptibility and progression. The reversible nature of epigenetics provides opportunities for the development of novel therapeutic strategies for CVD.

Involvement of Myeloid Cells and Noncoding RNA in Abdominal Aortic Aneurysm Disease

Significance: Abdominal aortic aneurysm (AAA) is a potentially fatal condition, featuring the possibility of high-mortality rupture. To date, prophylactic surgery by means of open surgical repair or endovascular aortic repair at specific thresholds is considered standard therapy. Both surgical options hold different risk profiles of short- and long-term morbidity and mortality. Targeting early stages of AAA development to decelerate disease progression is desirable. Recent Advances: Understanding the pathomechanisms that initiate formation, maintain growth, and promote rupture of AAA is crucial to developing new medical therapeutic options. Inflammatory cells, in particular macrophages, have been investigated for their contribution to AAA disease for decades, whereas evidence on lymphocytes, mast cells, and neutrophils is sparse. Recently, there has been increasing interest in noncoding RNAs (ncRNAs) and their involvement in disease development, including AAA. Critical Issues: The current evidence on myeloid cells and ncRNAs in AAA largely originates from small animal models, making clinical extrapolation difficult. Although it is feasible to collect surgical human AAA samples, these tissues reflect end-stage disease, preventing examination of critical mechanisms behind early AAA formation. Future Directions: Gaining more insight into how myeloid cells and ncRNAs contribute to AAA disease, particularly in early stages, might suggest nonsurgical AAA treatment options. The utilization of large animal models might be helpful in this context to help bridge translational results to humans.

LncRNAs in cardiac hypertrophy: From basic science to clinical application

Cardiac hypertrophy is a typical pathological phenotype of cardiomyopathy and a result from pathological remodelling of cardiomyocytes in humans. At present, emerging evidence demonstrated the roles of long non‐coding RNAs (lncRNAs) in regulating the pathophysiological process of cardiac hypertrophy. Herein, we would like to review the recent researches on this issue and try to analysis the potential therapeutic targets on lncRNA sites. Studies have revealed both genetic mutations related hypertrophic cardiomyopathy and the compensative cardiac hypertrophy due to pressure overload, inflammation, endocrine issues and other external stimulations, share a common molecular mechanism of ventricular hypertrophy. The emerging evidence identified the abnormal expression of lncRNAs would leading to the impairment the function of sarcomere, intracellular calcium handling and mitochondrial metabolisms. Several researches proved the therapeutic role of lncRNAs in preventing or reversing cardiac hypertrophy. With the development of delivery system for small pieces of oligonucleotide, clinicians could design gene therapy approaches to terminate the process of cardiac hypertrophy to provide better prognosis.

LncRNA H19 is involved in myocardial ischemic preconditioning via increasing the stability of nucleolin protein

Myocardial ischemic preconditioning (IP) is defined as a brief period of myocardial ischemia/reperfusion (I/R) that significantly reduces injury during the subsequent exposure to long-term I/R. However, the underlying mechanisms of myocardial IP are yet to be elucidated. This study investigated the expression and roles of long noncoding RNA (lncRNA) H19 in myocardial IP in vitro and in vivo. LncRNA H19 expression levels were analyzed by quantitative reverse-transcription polymerase chain reaction, cell viability was determined by the Cell Counting Kit-8 assay, apoptosis was evaluated based on the caspase 3 activity, and RNA immunoprecipitation was performed to examine the interaction between lncRNA H19 and nucleolin. The results of this study showed that lncRNA H19 expression was significantly upregulated in mouse hearts subjected to myocardial IP, in rat H9C2 cells exposed to H2 O2 preconditioning (H2 O2 -PC), and in neonatal rat cardiomyocytes subjected to hypoxia preconditioning. H19 knockdown abrogated the H2 O2 -PC-mediated protection in cardiomyocytes evidenced by the decreased cell viability and increased caspase-3 activity. Conversely, H19 overexpression enhanced the protective role of H2 O2 -PC in cardiomyocytes. In addition, H19 overexpression increased the expression of nucleolin, whereas H19 ablation abrogated H2 O2 -PC-induced upregulation of nucleolin in cardiomyocytes. Furthermore, H19 overexpression increased the stabilization of nucleolin; an interaction between H19 and nucleolin was identified using the RNA-protein interaction studies. Furthermore, nucleolin small interfering RNA relieved the protective role of lncRNA H19. These findings demonstrated that the lncRNA H19 is involved in myocardial IP via increasing the stability of nucleolin protein and lncRNA H19 may represent a potential therapeutic target for the treatment of the myocardial injury.

Genetic and Epigenetic Mechanisms Underlying Vascular Smooth Muscle Cell Phenotypic Modulation in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) refers to the localized dilatation of the infra-renal aorta, in which the diameter exceeds 3.0 cm. Loss of vascular smooth muscle cells, degradation of the extracellular matrix (ECM), vascular inflammation, and oxidative stress are hallmarks of AAA pathogenesis and contribute to the progressive thinning of the media and adventitia of the aortic wall. With increasing AAA diameter, and left untreated, aortic rupture ensues with high mortality. Collective evidence of recent genetic and epigenetic studies has shown that phenotypic modulation of smooth muscle cells (SMCs) towards dedifferentiation and proliferative state, which associate with the ECM remodeling of the vascular wall and accompanied with increased cell senescence and inflammation, is seen in in vitro and in vivo models of the disease. This review critically analyses existing publications on the genetic and epigenetic mechanisms implicated in the complex role of SMCs within the aortic wall in AAA formation and reflects the importance of SMCs plasticity in AAA formation. Although evidence from the wide variety of mouse models is convincing, how this knowledge is applied to human biology needs to be addressed urgently leveraging modern in vitro and in vivo experimental technology.

Atorvastatin enhances the therapeutic efficacy of mesenchymal stem cells-derived exosomes in acute myocardial infarction via up-regulating long non-coding RNA H19

AIMS

Naturally secreted nanovesicles, known as exosomes, play important roles in stem cell-mediated cardioprotection. We have previously demonstrated that atorvastatin (ATV) pretreatment improved the cardioprotective effects of mesenchymal stem cells (MSCs) in a rat model of acute myocardial infarction (AMI). The aim of this study was to investigate if exosomes derived from ATV-pretreated MSCs exhibit more potent cardioprotective function in a rat model of AMI and if so to explore the underlying mechanisms.

METHODS AND RESULTS

Exosomes were isolated from control MSCs (MSC-Exo) and ATV-pretreated MSCs (MSCATV-Exo) and were then delivered to endothelial cells and cardiomyocytes in vitro under hypoxia and serum deprivation (H/SD) condition or in vivo in an acutely infarcted Sprague-Dawley rat heart. Regulatory genes and pathways activated by ATV pretreatment were explored using genomics approaches and functional studies. In vitro, MSCATV-Exo accelerated migration, tube-like structure formation, and increased survival of endothelial cells but not cardiomyocytes, whereas the exosomes derived from MSCATV-Exo-treated endothelial cells prevented cardiomyocytes from H/SD-induced apoptosis. In a rat AMI model, MSCATV-Exo resulted in improved recovery in cardiac function, further reduction in infarct size and reduced cardiomyocyte apoptosis compared to MSC-Exo. In addition, MSCATV-Exo promoted angiogenesis and inhibited the elevation of IL-6 and TNF-α in the peri-infarct region. Mechanistically, we identified lncRNA H19 as a mediator of the role of MSCATV-Exo in regulating expression of miR-675 and activation of proangiogenic factor VEGF and intercellular adhesion molecule-1. Consistently, the cardioprotective effects of MSCATV-Exo was abrogated when lncRNA H19 was depleted in the ATV-pretreated MSCs and was mimicked by overexpression of lncRNA H19.

CONCLUSION

Exosomes obtained from ATV-pretreated MSCs have significantly enhanced therapeutic efficacy for treatment of AMI possibly through promoting endothelial cell function. LncRNA H19 mediates, at least partially, the cardioprotective roles of MSCATV-Exo in promoting angiogenesis.

Role of smooth muscle cells in Cardiovascular Disease

Normally, smooth muscle cells (SMCs) are localized in the tunica media of the vasculature, where they take responsibility for vascular contraction and extracellular matrix (ECM) generation. SMCs also play a significant role in obedience and elastic rebound of the artery in response to the haemodynamic condition. However, under pathological or stressed conditions, phenotype switching from contractile to synthetic state or other cell types will occur in SMCs to positively or negatively contribute to disease progression. Various studies demonstrated that functional changes of SMCs are implicated in several cardiovascular diseases. In this review, we present the function of vascular SMCs (VSMCs) and the involved molecular mechanisms about phenotype switching, and summarize the roles of SMCs in atherosclerosis, hypertension, arterial aneurysms and myocardial infarction, hoping to obtain potential therapeutic targets against cardiovascular disease in the clinical practices.

The Role of Long Non-Coding RNAs in Intracranial Aneurysms and Subarachnoid Hemorrhage

Intracranial aneurysms (IAs) represent the most complex and relevant problem of modern neurology and neurosurgery. They serve as one of the main causes of non-traumatic subarachnoid hemorrhage (SAH), causing up to 85% of all cases of intracranial hemorrhage, which is associated with frequent disability and high mortality among patients. Unfortunately, the molecular mechanisms of the development and rupture of IAs are still under study. Long non-coding RNAs (lncRNAs) are non-coding RNAs that typically have a length of more than 200 nucleotides. It is known that lncRNAs regulate many processes, such as transcription, translation, cell differentiation, regulation of gene expression, and regulation of the cell cycle. In recent years, a lot of evidence has established their role in human diseases from oncology to cardiovascular disease. Recent studies have shown that lncRNAs may be involved in the pathogenesis of IAs. The study of lncRNAs and its targets in various pathological conditions of a person is a rapidly developing field, and it is likely that the knowledge obtained from these studies regarding the pathogenesis of intracranial aneurysms will have the potential to use lncRNAs in therapy, as well as in the diagnosis and prediction of high aneurysms risk of rupture.

Noncoding RNAs in Cardiovascular Disease: Current Knowledge, Tools and Technologies for Investigation, and Future Directions: A Scientific Statement From the American Heart Association

BACKGROUND

The discovery that much of the non-protein-coding genome is transcribed and plays a diverse functional role in fundamental cellular processes has led to an explosion in the development of tools and technologies to investigate the role of these noncoding RNAs in cardiovascular health. Furthermore, identifying noncoding RNAs for targeted therapeutics to treat cardiovascular disease is an emerging area of research. The purpose of this statement is to review existing literature, offer guidance on tools and technologies currently available to study noncoding RNAs, and identify areas of unmet need.

METHODS

The writing group used systematic literature reviews (including MEDLINE, Web of Science through 2018), expert opinion/statements, analyses of databases and computational tools/algorithms, and review of current clinical trials to provide a broad consensus on the current state of the art in noncoding RNA in cardiovascular disease.

RESULTS

Significant progress has been made since the initial studies focusing on the role of miRNAs (microRNAs) in cardiovascular development and disease. Notably, recent progress on understanding the role of novel types of noncoding small RNAs such as snoRNAs (small nucleolar RNAs), tRNA (transfer RNA) fragments, and Y-RNAs in cellular processes has revealed a noncanonical function for many of these molecules. Similarly, the identification of long noncoding RNAs that appear to play an important role in cardiovascular disease processes, coupled with the development of tools to characterize their interacting partners, has led to significant mechanistic insight. Finally, recent work has characterized the unique role of extracellular RNAs in mediating intercellular communication and their potential role as biomarkers.

CONCLUSIONS

The rapid expansion of tools and pipelines for isolating, measuring, and annotating these entities suggests that caution in interpreting results is warranted until these methodologies are rigorously validated. Most investigators have focused on investigating the functional role of single RNA entities, but studies suggest complex interaction between different RNA molecules. The use of network approaches and advanced computational tools to understand the interaction of different noncoding RNA species to mediate a particular phenotype may be required to fully comprehend the function of noncoding RNAs in mediating disease phenotypes.

LncRNA H19 Regulates BMP2-Induced Hypertrophic Differentiation of Mesenchymal Stem Cells by Promoting Runx2 Phosphorylation

Objectives

Bone morphogenetic protein 2 (BMP2) triggers hypertrophic differentiation after chondrogenic differentiation of mesenchymal stem cells (MSCs), which blocked the further application of BMP2-mediated cartilage tissue engineering. Here, we investigated the underlying mechanisms of BMP2-mediated hypertrophic differentiation of MSCs.

Materials and Methods

In vitro and in vivo chondrogenic differentiation models of MSCs were constructed. The expression of H19 in mouse limb was detected by fluorescence in situ hybridization (FISH) analysis. Transgenes BMP2, H19 silencing, and overexpression were expressed by adenoviral vectors. Gene expression was determined by reverse transcription and quantitative real-time PCR (RT-qPCR), Western blot, and immunohistochemistry. Correlations between H19 expressions and other parameters were calculated with Spearman’s correlation coefficients. The combination of H19 and Runx2 was identified by RNA immunoprecipitation (RIP) analysis.

Results

We identified that H19 expression level was highest in proliferative zone and decreased gradually from prehypertrophic zone to hypertrophic zone in mouse limbs. With the stimulation of BMP2, the highest expression level of H19 was followed after the peak expression level of Sox9; meanwhile, H19 expression levels were positively correlated with chondrogenic differentiation markers, especially in the late stage of BMP2 stimulation, and negatively correlated with hypertrophic differentiation markers. Our further experiments found that silencing H19 promoted BMP2-triggered hypertrophic differentiation through in vitro and in vivo tests, which indicated the essential role of H19 for maintaining the phenotype of BMP2-induced chondrocytes. In mechanism, we characterized that H19 regulated BMP2-mediated hypertrophic differentiation of MSCs by promoting the phosphorylation of Runx2.

Conclusion

These findings suggested that H19 regulates BMP2-induced hypertrophic differentiation of MSCs by promoting the phosphorylation of Runx2.

Long Noncoding RNAs in Atherosclerosis and Vascular Injury: Pathobiology, Biomarkers, and Targets for Therapy

Despite major advances in the primary and secondary prevention of atherosclerosis and its risk factors, atherosclerotic cardiovascular disease remains a major clinical and financial burden on individuals and health systems worldwide. In addition, neointima formation and proliferation due to mechanical trauma to the vessel wall during percutaneous coronary interventions can lead to vascular restenosis and limit the longevity and effectiveness of coronary revascularization. Long noncoding RNAs (lncRNAs) have emerged as a novel class of epigenetic regulators with critical roles in the pathogenesis of atherosclerosis and restenosis following vascular injury. Here, we provide an in-depth review of lncRNAs that regulate the development of atherosclerosis or contribute to the pathogenesis of restenosis following mechanical vascular injury. We describe the diverse array of intracellular mechanisms by which lncRNAs exert their regulatory effects. We highlight the utility and challenges of lncRNAs as biomarkers. Finally, we discuss the immense translational potential of lncRNAs and strategies for targeting them therapeutically using oligonucleotide-based therapeutics and novel gene therapy platforms.

Long non-coding RNA H19 in atherosclerosis: what role?

Atherosclerosis (AS) is widely accepted to be a multistep pathophysiological process associated with several other processes such as angiogenesis and inflammatory response. Long non-coding RNAs (lncRNAs) are non-protein coding RNAs (more than 200 nucleotides in length) and can regulate gene expression at the transcriptional and post-transcriptional levels. Recent studies suggest that lncRNA-H19 plays important roles in the regulation of angiogenesis, adipocyte differentiation, lipid metabolism, inflammatory response, cellular proliferation and apoptosis. In this review, we primarily discuss the roles of lncRNA-H19 in atherosclerosis-related pathophysiological processes and the potential mechanisms by which lncRNA-H19 regulates the development of atherosclerosis, to help provide a better understanding of the biological functions of lncRNA-H19 in atherosclerosis.

lncRNA IGKJ2-MALLP2 suppresses LSCC proliferation, migration, invasion, and angiogenesis by sponging miR-1911-3p/p21

Because advanced laryngeal squamous cell carcinoma (LSCC) is diagnosed as a malignant tumor with a poor prognosis, the associated mechanisms still need to be further investigated. As key players in the development and progression of LSCC, lncRNAs have attracted increasing attention from many researchers. In this study, a novel lncRNA termed IGKJ2‐MALLP2 was identified and investigated for its effects on the development of LSCC. IGKJ2‐MALLP2 expression was confirmed by RT‐qPCR in 78 pairs of tissues and human laryngeal carcinoma cell lines. The results of this study showed that the expression of IGKJ2‐MALLP2 was reduced in LSCC tissues and displayed close relationships with tumor stage, lymph node metastasis, and clinical stage. Using a dual‐luciferase reporter assay, the ability of miR‐1911‐3p to bind both IGKJ2‐MALLP2 and p21 mRNA was demonstrated. IGKJ2‐MALLP2 could upregulate p21 expression by competitively binding miR‐1911‐3p. Moreover, IGKJ2‐MALLP2 effectively hindered the invasion, migration, and proliferation of AMC‐HN‐8 and TU212 tumor cells. Furthermore, its high expression could hinder the secretion of VEGF‐A and suppress angiogenesis. As revealed by the results of in vitro experiments, IGKJ2‐MALLP2 overexpression could restrict tumor growth and blood vessel formation in a xenograft model of LSCC. As indicated from the mentioned findings, IGKJ2‐MALLP2, which mediates p21 expression by targeting miR‐1911‐3p, was capable of regulating LSCC progression and could act as an underlying therapeutic candidate to treat LSCC.

SPECT/CT imaging of apoptosis in aortic aneurysm with radiolabeled duramycin

The objective of this research was to estimate whether a ^[99mTc]duramycin probe can be used for apoptosis imaging in patients with aortic aneurysm (AA). Vascular smooth muscle cell (SMC) apoptosis has an important influence on AA development. Thus, non-invasive imaging of SMC apoptosis may be able to evaluate AA progress and risk stratification. SMCs were treated with hydrogen peroxide (H₂O₂; 200 μΜ) or culture medium as a control. Apoptosis was measured using flow cytometry and ^[99mTc]duramycin to detect the binding efficiency to apoptotic SMCs. C57/BL6 mice were administered angiotensin-II and beta-aminopropionitrile (BAPN) subcutaneously to establish an AA model, or saline for controls. Aortic specimens underwent pathological evaluation and their aortic diameters were measured after 6 weeks. Micro-SPECT/CT scanning of ^[99mTc]duramycin and ¹⁸F-FDG PET detection were performed. SMCs treated with H₂O₂ showed more apoptosis compared with the control group (67.2 ± 3.8% vs. 16.1 ± 0.6%, P < 0.01). The experimental group showed a high rate of AA formation (70%) compared with no AA formation in the control group. The average aorta diameter was higher and ^[99mTc]duramycin uptake at the AA site was higher in the experimental group compared with the control group. Compared with the normal aorta in the control group, AA in experiment group had more severe medial degeneration, elastic fiber reduction and fracture, and collagen degeneration. TUNEL staining verified the higher apoptosis rate at the AA site in experiment group compared with the control group (63.9 ± 3.7% in ascending AA, 66.4 ± 4.0% in thoracic AA, vs. 3.5 ± 0.3% in normal aorta, P < 0.01). ^[99mTc]Duramycin may be an effective probe to evaluate apoptosis in AA.

Long non‑coding RNA H19 is involved in sorafenib resistance in hepatocellular carcinoma by upregulating miR‑675

Sorafenib is the first‑line treatment for advanced hepatocellular carcinoma (HCC). Since many HCC patients experience drug resistance, there is an urgent need to discover more effective therapeutic strategies to overcome drug resistance. Long non‑coding RNAs (lncRNAs) play an important role in tumor drug resistance. However, research on the role of lncRNA H19 in sorafenib resistance in HCC is quite limited. In the present study, CCK‑8 assay, RT‑qPCR, EdU staining, immunofluorescence staining, and western blot analysis were used to detect the effect of lncRNA H19 on sorafenib resistance of HCC cells. H19 expression was found to be negatively related to sorafenib sensitivity in HCC cells. Knockdown of lncRNA H19 elevated sorafenib sensitivity by suppressing epithelial‑mesenchymal transition (EMT) in HCC cells. H19 upregulated miR‑675 expression. miR‑675 inhibitor decreased the cell viability in sorafenib‑treated HCC cells, while miR‑675 overexpression had the opposite effect on the treated cells. When the cells were pretreated with miR‑675 mimic, H19 siRNA did not alter the effect of miR‑675 on sorafenib sensitivity. In conclusion, our study provides new clues for further clinical treatment of sorafenib‑resistant liver cancer patients.

LncRNA LBX2-AS1 facilitates abdominal aortic aneurysm through miR-4685-5p/LBX2 feedback loop

Long noncoding RNAs (LncRNAs) are involved in multiple processes of human malignancy, and emerge as crucial molecules in RNA biology. However, the function of lncRNAs has not been well illustrated in abdominal aortic aneurysm (AAA). In this research, the effects of dysregulated ladybird homeobox 2 antisense RNA 1 (LBX2-AS1) or ladybird homeobox 2 (LBX2) on vascular smooth muscle cell (VSMC) biological processes were surveyed via cell counting kit-8 (CCK-8), methyl thiazolyl tetrazolium (MTT), terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) and caspase-3 activity assays. LBX2-AS1 and LBX2 both possessed pro-apoptosis and anti-proliferation functions in AAA. Mechanically, the regulation role of LBX2-AS1 on miR-4685-5p or that of miR-4685-5p on LBX2 was investigated by quantitative real-time polymerase chain reaction (qRT-PCR). Additionally, the competing endogenous RNA (ceRNA) network was confirmed by luciferase reporter, RNA pull-down, and RNA immunoprecipitation (RIP) assays. LBX2-AS1 sequestered miR-4685-5p to release LBX2 expression via ceRNA mechanism. Further, LBX2 could act as a transcriptional activator of LBX2-AS1. A positive feedback loop was formed by LBX2-AS1, miR-4685-5p and LBX2, deteriorating AAA formation and progression. To sum up, our data suggested that LBX2-AS1, miR-4685-5p and LBX2 constituted a positive feedback loop in promoting AAA development, implying a potential usage of LBX2-AS1/miR-4685-5p/LBX2 axis in AAA management.

METTL3 Induces AAA Development and Progression by Modulating N6-Methyladenosine-Dependent Primary miR34a Processing

Identifying effective drugs to delay the progression of aortic aneurysms is a formidable challenge in vascular medicine. Methyltransferase-like 3 (METTL3) plays a key role in catalyzing the formation of N6-methyladenosine (m⁶A), but despite the functional importance of METTL3 and m⁶A in various fundamental biological processes, their roles in abdominal aortic aneurysm (AAA) are unknown. Here, we found that METTL3 knockdown in apolipoprotein E-deficient (ApoE^−/−) mice treated with angiotensin II suppressed the formation of AAAs, while METTL3 overexpression exerted the opposite effects. Similar results were obtained in a calcium chloride (CaCl₂)-induced mouse AAA model. Mechanistically, METTL3-dependent m⁶A methylation promoted primary microRNA-34a (miR-34a, pri-miR34a) maturation through DGCR8. Moreover, miR-34a overexpression significantly decreased SIRT1 expression and aggravated AAA formation, while miR-34a deficiency produced the opposite effects. In a rescue experiment, miR-34a knockdown or forced expression of SIRT1 partially attenuated the protective effects of METTL3 deficiency against AAA formation. Our studies reveal an important role for METTL3/m⁶A-mediated miR-34a maturation in AAA formation and provide a novel therapeutic target and diagnostic biomarker for AAA treatment.

Knockdown of long noncoding RNA CCDC144NL-AS1 attenuates migration and invasion phenotypes in endometrial stromal cells from endometriosis†

Endometriosis (EM) is a mysterious and complicated disease that has been found to be multifactorial. Recent studies demonstrated that long noncoding RNAs (lncRNAs) play an important role in the pathogenesis of EM. However, the functional and biological mechanisms of lncRNAs in EM remain unknown. Here, we performed microarray analyses to compare the lncRNA expression profiles of four paired ectopic endometrial (EC) tissues and eutopic endometrial (EU) tissues from patients with ovarian EM. A novel lncRNA, CCDC144NL-AS1, was identified as being potentially functional. CCDC144NL-AS1 expression was upregulated in EC tissues compared to EU and normal endometrial (NE) tissues. Its expression was higher in EC tissues than in EU tissues in 86.7% (26/30) of patients with EM. Despite the lack of a significant increase according to revised American Fertility Society (rAFS) stages, approximately 60% of stage VI EM cases exhibited higher CCDC144NL-AS1 levels, many more than in the stage II-III cases. Subcellular fractionation demonstrated that CCDC144NL-AS1 was localized in the cytoplasm and nucleus of the human EM-derived immortalized endometrial stromal cell line hEM15A. CCDC144NL-AS1 depletion suppressed the migration and invasion of hEM15A cells, but exerted no effects on cell adhesion, proliferation, apoptosis, or cell cycle. Knockdown of CCDC144NL-AS1 dramatically altered the distribution of cytoskeletal filamentous actin (F-actin) stress fibers compared to the negative control group treatment. Western blot analysis revealed that knockdown of CCDC144NL-AS1 attenuated the protein levels of vimentin filaments and MMP-9, but not N-cadherin or β-catenin. Collectively, our results suggest that CCDC144NL-AS1 might be involved in the pathogenesis of EM and provide a novel target for ovarian EM.

H19/TET1 axis promotes TGF-β signaling linked to endothelial-to-mesenchymal transition

While emerging evidence suggests the link between endothelial activation of TGF-β signaling, induction of endothelial-to-mesenchymal transition (EndMT), and cardiovascular disease (CVD), the molecular underpinning of this connection remains enigmatic. Here, we report aberrant expression of H19 lncRNA and TET1 in endothelial cells (ECs) of human atherosclerotic coronary arteries. Using primary human umbilical vein endothelial cells (HUVECs) and aortic endothelial cells (HAoECs) we show that TNF-α, a known risk factor for endothelial dysfunction and CVD, induces H19 expression which in turn activates TGF-β signaling and EndMT via a TET1-dependent epigenetic mechanism. We also show that H19 regulates TET1 expression at the posttranscriptional level. Further, we provide evidence that this H19/TET1-mediated regulation of TGF-β signaling and EndMT occurs in mouse pulmonary microvascular ECs in vivo under hyperglycemic conditions. We propose that endothelial activation of the H19/TET1 axis may play an important role in EndMT and perhaps CVD.

LncRNA CRNDE affects the proliferation and apoptosis of vascular smooth muscle cells in abdominal aortic aneurysms by regulating the expression of Smad3 by Bcl-3

Previous studies show that Long non-coding RNAs (LncRNAs) are involved in the regulation of various human diseases. This study aimed to reveal how LncRNA CRNDE regulated vascular smooth muscle cells (VSMCs) proliferation and apoptosis in abdominal aortic aneurysms (AAA). Here, we found CRNDE was down-regulated in AAA tissues and AngII-stimulated VSMCs. The overexpression of CRNDE promoted VSMCs proliferation and inhibited cell apoptosis. The interaction between CRNDE and Bcl-3 or Bcl-3 and Smad3 was verified. The interference with Bcl-3 or CRNDE reduced Smad3 stability or promoted Smad3 ubiquitination. After pcDNA-CRNDE or pcDNA-CRNDE+si-Bcl-3 was transfected into VSMCs and stimulated with AngII, CRNDE affected VSMCs proliferation and apoptosis via regulating Smad3 via Bcl-3. Vivo experiments showed the overexpression of CRNDE repressed AAA growth. Therefore, we concluded that CRNDE was down-regulated in AAA tissues and AngII-stimulated VSMCs. Furthermore, the overexpression of CRNDE promoted VSMCs proliferation and repressed cell apoptosis in AAA by up-regulating Smad3 via Bcl-3.

Noncoding RNAs in Vascular Diseases

The advent of deep sequencing technologies led to the identification of a considerable amount of noncoding RNA transcripts, which are increasingly recognized for their functions in controlling cardiovascular diseases. MicroRNAs have already been studied for a decade, leading to the identification of several vasculoprotective and detrimental species, which might be considered for therapeutic targeting. Other noncoding RNAs such as circular RNAs, YRNAs, or long noncoding RNAs are currently gaining increasing attention, and first studies provide insights into their functions as mediators or antagonists of vascular diseases in vivo. The present review article will provide an overview of the different types of noncoding RNAs controlling the vasculature and focus on the developing field of long noncoding RNAs.

Expedition to the missing link: Long noncoding RNAs in cardiovascular diseases

With the advances in deep sequencing-based transcriptome profiling technology, it is now known that human genome is transcribed more pervasively than previously thought. Up to 90% of the human DNA is transcribed, and a large proportion of the human genome is transcribed as long noncoding RNAs (lncRNAs), a heterogenous group of non-coding transcripts longer than 200 nucleotides. Emerging evidence suggests that lncRNAs are functional and contribute to the complex regulatory networks involved in cardiovascular development and diseases. In this article, we will review recent evidence on the roles of lncRNAs in the biological processes of cardiovascular development and disorders. The potential applications of lncRNAs as biomarkers and targets for therapeutics are also discussed.

Icariin affects cell cycle progression and proliferation of human retinal pigment epithelial cells via enhancing expression of H19

Background

Aberrant proliferation of retinal pigment epithelial (RPE) cells under pathologic condition results in the occurrence of proliferative vitreoretinopathy (PVR). Icariin (ICA)-a flavonol glucoside-has been shown to inhibit proliferation of many cell types, but the effect on RPE cells is unknown. This study aimed to clarify the inhibitory effects of ICA on RPE cells against platelet-derived growth factor (PDGF)-BB-induced cell proliferation, and discuss the regulatory function of H19 in RPE cells.

Methods

MTS assay was conducted to determine the effects of ICA on cell proliferation. Flow cytometry analysis was performed to detect cell cycle progression. Quantitative real-time PCR and western blot assay were used to measure the expression patterns of genes in RPE cells.

Results

ICA significantly suppressed PDGF-BB-stimulated RPE cell proliferation in a concentration-dependent manner. Moreover, since administration of ICA induced cell cycle G0/G1 phase arrest, the anti-proliferative activity of ICA may be due to G0/G1 phase arrest in RPE cells. At molecular levels, cell cycle regulators cyclin D1, CDK4, CDK6, p21 and p53 were modulated in response to treatment with ICA. Most importantly, H19 was positively regulated by ICA and H19 depletion could reverse the inhibitory effects of ICA on cell cycle progression and proliferation in PDGF-BB-stimulated RPE cells. Further mechanical explorations showed that H19 knockdown resulted in alternative expressions levels of cyclin D1, CDK4, CDK6, p21 and p53 under ICA treatment.

Conclusions

Our findings revealed that ICA was an effective inhibitor of PDGF-BB-induced RPE cell proliferation through affecting the expression levels of cell cycle-associated factors, and highlighted the potential application of ICA in PVR therapy. H19 was described as a target regulatory gene of ICA whose disruption may contribute to excessive proliferation of RPE cells, suggesting that modulation of H19 expression may be a novel therapeutic approach to treat PVR.

Germinal Center-Derived Antibodies Promote Atherosclerosis Plaque Size and Stability

BACKGROUND

Atherosclerosis progression is modulated by interactions with the adaptive immune system. Humoral immunity can help protect against atherosclerosis formation; however, the existence, origin, and function of putative atherogenic antibodies are controversial. How such atherosclerosis-promoting antibodies could affect the specific composition and stability of plaques, as well as the vasculature generally, remains unknown.

METHODS

We addressed the overall contribution of antibodies to atherosclerosis plaque formation, composition, and stability in vivo (1) with mice that displayed a general loss of antibodies, (2) with mice that had selectively ablated germinal center-derived IgG production, or (3) through interruption of T-B-cell interactions and further studied the effects of antibody deficiency on the aorta by transcriptomics.

RESULTS

Here, we demonstrate that atherosclerosis-prone mice with attenuated plasma cell function manifest reduced plaque burden, indicating that antibodies promote atherosclerotic lesion size. However, the composition of the plaque was altered in antibody-deficient mice, with an increase in lipid content and decreases in smooth muscle cells and macrophages, resulting in an experimentally validated vulnerable plaque phenotype. Furthermore, IgG antibodies enhanced smooth muscle cell proliferation in vitro in an Fc receptor-dependent manner, and antibody-deficient mice had decreased neointimal hyperplasia formation in vivo. These IgG antibodies were shown to be derived from germinal centers, and mice genetically deficient for germinal center formation had strongly reduced atherosclerosis plaque formation. mRNA sequencing of aortas revealed that antibodies are required for the sufficient expression of multiple signal-induced and growth-promoting transcription factors and that aortas undergo large-scale metabolic reprograming in their absence. Using an elastase model, we demonstrated that absence of IgG results in an increased severity of aneurysm formation.

CONCLUSIONS

We propose that germinal center-derived IgG antibodies promote the size and stability of atherosclerosis plaques, through promoting arterial smooth muscle cell proliferation and maintaining the molecular identity of the aorta. These results could have implications for therapies that target B cells or B-T-cell interactions because the loss of humoral immunity leads to a smaller but less stable plaque phenotype.

Preclinical and Clinical Development of Noncoding RNA Therapeutics for Cardiovascular Disease

RNA modulation has become a promising therapeutic approach for the treatment of several types of disease. The emerging field of noncoding RNA-based therapies has now come to the attention of cardiovascular research, in which it could provide valuable advancements in comparison to current pharmacotherapy such as small molecule drugs or antibodies. In this review, we focus on noncoding RNA-based studies conducted mainly in large-animal models, including pigs, rabbits, dogs, and nonhuman primates. The obstacles and promises of targeting long noncoding RNAs and circRNAs as therapeutic modalities in humans are specifically discussed. We also describe novel ex vivo methods based on human cells and tissues, such as engineered heart tissues and living myocardial slices that could help bridging the gap between in vivo models and clinical applications in the future. Finally, we summarize antisense oligonucleotide drugs that have already been approved by the Food and Drug Administration for targeting mRNAs and discuss the progress of noncoding RNA-based drugs in clinical trials. Additional factors, such as drug chemistry, drug formulations, different routes of administration, and the advantages of RNA-based drugs, are also included in the present review. Recently, first therapeutic miRNA-based inhibitory strategies have been tested in heart failure patients as well as healthy volunteers to study effects on wound healing (NCT04045405; NCT03603431). In summary, a combination of novel therapeutic RNA targets, large-animal models, ex vivo studies with human cells/tissues, and new delivery techniques will likely lead to significant progress in the development of noncoding RNA-based next-generation therapeutics for cardiovascular disease.

Suspended in time: Molecular responses to hibernation also promote longevity

Aging in most animals is an inevitable process that causes or is a result of physiological, biochemical, and molecular changes in the body, and has a strong influence on an organism's lifespan. Although advancement in medicine has allowed humans to live longer, the prevalence of age-associated medical complications is continuously burdening older adults worldwide. Current animal models used in research to study aging have provided novel information that has helped investigators understand the aging process; however, these models are limiting. Aging is a complex process that is regulated at multiple biological levels, and while a single manipulation in these models can provide information on a process, it is not enough to understand the global regulation of aging. Some mammalian hibernators live up to 9.8-times higher than their expected average lifespan, and new research attributes this increase to their ability to hibernate. A common theme amongst these mammalian hibernators is their ability to greatly reduce their metabolic rate to a fraction of their normal rate and initiate cytoprotective responses that enable their survival. Metabolic rate depression is strictly regulated at different biological levels in order to enable the animal to not only survive, but to also do so by relying mainly on their limited internal fuels. As such, understanding both the global and specific regulatory mechanisms used to promote survival during hibernation could, in theory, allow investigators to have a better understanding of the aging process. This can also allow pharmaceutical industries to find therapeutics that could delay or reverse age-associated medical complications and promote healthy aging and longevity in humans.

Cellular signaling in Abdominal Aortic Aneurysm

Abdominal aortic aneurysms (AAAs) are highly lethal cardiovascular diseases without effective medications. However, the molecular and signaling mechanisms remain unclear. A series of pathological cellular processes have been shown to contribute to AAA formation, including vascular extracellular matrix remodeling, inflammatory and immune responses, oxidative stress, and dysfunction of vascular smooth muscle cells. Each cellular process involves complex cellular signaling, such as NF-κB, MAPK, TGFβ, Notch and inflammasome signaling. In this review, we discuss how cellular signaling networks function in various cellular processes during the pathogenesis and progression of AAA. Understanding the interaction of cellular signaling networks with AAA pathogenesis as well as the crosstalk of different signaling pathways is essential for the development of novel therapeutic approaches to and personalized treatments of AAA diseases.

Meprin-α (Mep1A) enhances TNF-α secretion by mast cells and aggravates abdominal aortic aneurysms

BACKGROUND AND PURPOSE

Abdominal aorticaneurysm (AAA) rupture is mainly due to elastic lamina degradation. As a metalloendopeptidase, meprin-α (Mep1A) critically modulates the activity of proteins and inflammatory cytokines in various diseases. Here, we sought to investigate the functional role of Mep1A in AAA formation and rupture.

EXPERIMENTAL APPROACH

AAA tissues were detected by using real-time PCR (RT-PCR), western blotting (WB), and immunohistochemistry. Further mechanistic studies used RT-PCR, WB, and enzyme-linked immunosorbent assays.

KEY RESULTS

Mep1A mediated AAA formation by regulating the mast cell (MC) secretion of TNF-α, which promoted matrix metalloproteinase (MMP) expression and apoptosis in smooth muscle cells (SMCs). Importantly, increased Mep1A expression was found in human AAA tissues and in angiotensin II-induced mouse AAA tissues. Mep1A deficiency reduced AAA formation and increased the survival rate of AAA mice. Pathological analysis showed that Mep1A deletion decreased elastic lamina degradation and SMC apoptosis in AAA tissues. Furthermore, Mep1A was expressed mainly in MCs, wherein it mediated TNF-α expression. Mep1A inhibitor actinonin significantly inhibited TNF-α secretion in MCs. TNF-α secreted by MCs enhanced MMP2 expression in SMCs and promoted SMC apoptosis.

CONCLUSION AND IMPLICATIONS

Taken together, these data suggest that Mep1A may be vital in AAA pathophysiology by regulating TNF-α production by MCs. Knocking out Mep1A significantly decreased AAA diameter and improved AAA stability in mice. Therefore, Mep1A is a potential new therapeutic target in the development of AAA.

Genetic and epigenetic regulation of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are focal dilations of the aorta that develop from degenerative changes in the media and adventitia of the vessel. Ruptured AAAs have a mortality of up to 85%, thus it is important to identify patients with AAA at increased risk for rupture who would benefit from increased surveillance and/or surgical repair. Although the exact genetic and epigenetic mechanisms regulating AAA formation are not completely understood, Mendelian cases of AAA, which result from pathologic variants in a single gene, have helped provide a basic understanding of AAA pathophysiology. More recently, genome wide associated studies (GWAS) have identified additional variants, termed single nucleotide polymorphisms, in humans that may be associated with AAAs. While some variants may be associated with AAAs and play causal roles in aneurysm pathogenesis, it should be emphasized that the majority of SNPs do not actually cause disease. In addition to GWAS, other studies have uncovered epigenetic causes of disease that regulate expression of genes known to be important in AAA pathogenesis. This review describes many of these genetic and epigenetic contributors of AAAs, which altogether provide a deeper insight into AAA pathogenesis.

LINC00473 inhibits vascular smooth muscle cell viability to promote aneurysm formation via miR-212-5p/BASP1 axis

Abdominal aortic aneurysm (AAA), as the most common type of aortic aneurysm, is closely related to the proliferation and apoptosis ability of vascular smooth muscle cells (VSMCs). Long non-coding RNAs (lncRNAs) are emerging regulators in disease development. LncRNA LINC00473 has been shown to affect cell proliferation and apoptosis in various cancers, but its role in AAA is still blank. In this work, in vitro AAA models were successfully established since cell viability was inhibited whereas apoptosis stimulated in VSMCs treated with H₂O₂. LINC00473 was up-regulated in VSMCs after H₂O₂ treatment. Overexpression of LINC00473 inhibited VSMC cell proliferation and promoted cell apoptosis and its silence mitigated H₂O₂-induced injuries to VSMCs. Additionally, we uncovered that LINC00473 sponged miR-212-5p to regulate brain acid soluble protein 1 (BASP1) expression. Finally, rescue assays uncovered that overexpression of miR-212-5p or suppression of BASP1 reversed the effects of LINC00473 up-regulation on cell proliferation and cell apoptosis. And the positive correlation between LINC00473 and BASP1 as well as the negative relation of miR-212-5p to both LINC00473 and BASP1 were confirmed in AAA tissues. All finding illuminated that LINC00473 participated in AAA development by regulating miR-212-5p/BASP1 pathway, suggesting LINC00473 as a promising target for AAA therapy.

Epigenetic Signaling and RNA Regulation in Cardiovascular Diseases

RNA epigenetics is perhaps the most recent field of interest for translational epigeneticists. RNA modifications create such an extensive network of epigenetically driven combinations whose role in physiology and pathophysiology is still far from being elucidated. Not surprisingly, some of the players determining changes in RNA structure are in common with those involved in DNA and chromatin structure regulation, while other molecules seem very specific to RNA. It is envisaged, then, that new small molecules, acting selectively on RNA epigenetic changes, will be reported soon, opening new therapeutic interventions based on the correction of the RNA epigenetic landscape. In this review, we shall summarize some aspects of RNA epigenetics limited to those in which the potential clinical translatability to cardiovascular disease is emerging.

LncRNA H19 initiates microglial pyroptosis and neuronal death in retinal ischemia/reperfusion injury

Ischemia-reperfusion (I/R) is a common pathology when the blood supply to an organ was disrupted and then restored. During the reperfusion process, inflammation and tissue injury were triggered, which were mediated by immunocytes and cytokines. However, the mechanisms initiating I/R-induced inflammation and driving immunocytes activation remained largely unknown. In this study, we identified long non-coding RNA (lncRNA)-H19 as the key onset of I/R-induced inflammation. We found that I/R increased lncRNA-H19 expression to significantly promote NLRP3/6 inflammasome imbalance and resulted in microglial pyroptosis, cytokines overproduction, and neuronal death. These damages were effectively inhibited by lncRNA-H19 knockout. Specifically, lncRNA-H19 functioned via sponging miR-21 to facilitate PDCD4 expression and formed a competing endogenous RNA network (ceRNET) in ischemic cascade. LncRNA H19/miR-21/PDCD4 ceRNET can directly regulate I/R-induced sterile inflammation and neuronal lesion in vivo. We thus propose that lncRNA-H19 is a previously unknown danger signals in the molecular and immunological pathways of I/R injury, and pharmacological approaches to inhibit H19 seem likely to become treatment modalities for patients in the near future based on these mechanistic findings.

LUCAT1 contributes to MYRF-dependent smooth muscle cell apoptosis and may facilitate aneurysm formation via the sequestration of miR-199a-5p

The overwhelming number of interrogations reveals the implication of long noncoding RNAs (lncRNAs) in diverse malignancies, little is unveiled about lncRNAs participation in the abdominal aortic aneurysm (AAA). The study aimed to monitor the role and responsible mechanism of LUCAT1 in AAA. The cellular function of LUCAT1 on smooth muscle cells (SMCs) proliferation and apoptosis were examined through the conduction of CCK-8, EdU, TUNEL, and caspase-3 activity assays. LUCAT1 depletion was observed to boost SMCs proliferation or suppress SMCs apoptosis. The opposite results on SMCs proliferation and apoptosis were achieved in response to LUCAT1 promotion. The abundance of LUCAT1 in the cytoplasm was ascertained by subcellular fractionation and FISH analyses on the basis of LncLocator prediction. The binding of LUCAT1 to miR-199a-5p predicted by DIANA and starbase was certified by luciferase reporter assay and RIP analysis. Besides, multiple prediction tools unveiled the interaction between miR-199a-5p and myelin regulatory factor (MYRF). Quantitative real-time polymerase chain reaction uncovered the suppressive effect of miR-199a-5p and the positive regulation of LUCAT1 on MYRF expression. Rescue experiments revealed that LUCAT1 depletion pose suppression on SMCs apoptosis and MYRF elevation abrogated this suppression induced by LUCAT1 inhibition. These findings unmasked that the pro-apoptosis impact of LUCAT1 in SMCs via directly targeting miR-199a-5p to elevate MYRF expression, which may provide valuable information on AAA prevention.

Long noncoding RNAs in key cellular processes involved in aortic aneurysms

Aortic aneurysm (AA) is a complex and dangerous vascular disease, featuring progressive and irreversible vessel dilatation. AA is typically detected either by screening, or identified incidentally through imaging studies. To date, no effective pharmacological therapies have been identified for clinical AA management, and either endovascular repair or open surgery remains the only option capable of preventing aneurysm rupture. In recent years, multiple research groups have endeavored to both identify noncoding RNAs and to clarify their function in vascular diseases, including aneurysmal pathologies. Notably, the molecular roles of noncoding RNAs in AA development appear to vary significantly between thoracic aortic aneurysms (TAAs) and abdominal aortic aneurysms (AAAs). Some microRNAs (miRNA - a non-coding RNA subspecies) appear to contribute to AA pathophysiology, with some showing major potential for use as biomarkers or as therapeutic targets. Studies of long noncoding RNAs (lncRNAs) are more limited, and their specific contributions to disease development and progression largely remain unexplored. This review aims to summarize and discuss the most current data on lncRNAs and their mediation of AA pathophysiology.

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This current review covers studies that have identified long non-coding RNAs in aortic aneurysm development and progression.

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We separately discuss transcripts and mechanisms of importance to thoracic as well as abdominal aortic aneurysms.

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Functional data on lncRNAs being identified are highlighted.

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Some have been studied in human as well as experimental models of the disease pathology.