The lncRNA ANRIL regulates endothelial dysfunction by targeting the let-7b/TGF-βR1 signalling pathway

LncRNAs Are Key Regulators of Transcription Factor-Mediated Endothelial Stress Responses

The functional role of long noncoding RNAs in the endothelium is highly diverse. Among their many functions, regulation of transcription factor activity and abundance is one of the most relevant. This review summarizes the recent progress in the research on the lncRNA-transcription factor axes and their implications for the vascular endothelium under physiological and pathological conditions. The focus is on transcription factors critical for the endothelial response to external stressors, such as hypoxia, inflammation, and shear stress, and their lncRNA interactors. These regulatory interactions will be exemplified by a selected number of lncRNAs that have been identified in the endothelium under physiological and pathological conditions that are influencing the activity or protein stability of important transcription factors. Thus, lncRNAs can add a layer of cell type-specific function to transcription factors. Understanding the interaction of lncRNAs with transcription factors will contribute to elucidating cardiovascular disease pathologies and the development of novel therapeutic approaches.

Non-Coding RNA Involved in the Pathogenesis of Atherosclerosis-A Narrative Review

Atherosclerosis is a highly prevalent condition associated with lipid accumulation in the intima layer of arterial blood vessels. The development of atherosclerotic plaques is associated with the incidence of major cardiovascular events, such as acute coronary syndrome or ischemic stroke. Due to the significant prevalence of atherosclerosis and its subclinical progression, it is associated with severe and potentially lethal complications. The pathogenesis of atherosclerosis is complex and not entirely known. The identification of novel non-invasive diagnostic markers and treatment methods that could suppress the progression of this condition is highly required. Non-coding RNA (ncRNA) involves several subclasses of RNA molecules. microRNA (miRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA) differently regulate gene expression. Importantly, these molecules are frequently dysregulated under pathological conditions, which is associated with enhanced or suppressed expression of their target genes. In this review, we aim to discuss the involvement of ncRNA in crucial mechanisms implicated in the pathogenesis of atherosclerosis. We summarize current evidence on the potential use of these molecules as diagnostic and therapeutic targets.

N6-methyladenosine modification of KLF2 may contribute to endothelial-to-mesenchymal transition in pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) is a progressive disease characterized by pulmonary vascular remodeling. Increasing evidence indicates that endothelial-to-mesenchymal transition (EndMT) in pulmonary artery endothelial cells (PAECs) is a pivotal trigger initiating this remodeling. However, the regulatory mechanisms underlying EndMT in PH are still not fully understood.

METHODS

Cytokine-induced hPAECs were assessed using RNA methylation quantification, qRT-PCR, and western blotting to determine the involvement of N6-methyladenosine (m6A) methylation in EndMT. Lentivirus-mediated silencing, overexpression, tube formation, and wound healing assays were utilized to investigate the function of METTL3 in EndMT. Endothelial-specific gene knockout, hemodynamic measurement, and immunostaining were performed to explore the roles of METTL3 in pulmonary vascular remodeling and PH. RNA-seq, RNA Immunoprecipitation-based qPCR, mRNA stability assay, m6A mutation, and dual-luciferase assays were employed to elucidate the mechanisms of RNA methylation in EndMT.

RESULTS

The global levels of m6A and METTL3 expression were found to decrease in TNF-α- and TGF-β1-induced EndMT in human PAECs (hPAECs). METTL3 inhibition led to reduced endothelial markers (CD31 and VE-cadherin) and increased mesenchymal markers (SM22 and N-cadherin) as well as EndMT-related transcription factors (Snail, Zeb1, Zeb2, and Slug). The endothelial-specific knockout of Mettl3 promoted EndMT and exacerbated pulmonary vascular remodeling and hypoxia-induced PH (HPH) in mice. Mechanistically, METTL3-mediated m6A modification of kruppel-like factor 2 (KLF2) plays a crucial role in the EndMT process. KLF2 overexpression increased CD31 and VE-cadherin levels while decreasing SM22, N-cadherin, and EndMT-related transcription factors, thereby mitigating EndMT in PH. Mutations in the m6A site of KLF2 mRNA compromise KLF2 expression, subsequently diminishing its protective effect against EndMT. Furthermore, KLF2 modulates SM22 expression through direct binding to its promoter.

CONCLUSIONS

Our findings unveil a novel METTL3/KLF2 pathway critical for protecting hPAECs against EndMT, highlighting a promising avenue for therapeutic investigation in PH.

Noncoding RNAs in atherosclerosis: regulation and therapeutic potential

Atherosclerosis, a chronic disease of arteries, results in high mortality worldwide as the leading cause of cardiovascular disease. The development of clinically relevant atherosclerosis involves the dysfunction of endothelial cells and vascular smooth muscle cells. A large amount of evidence indicates that noncoding RNAs, such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), are involved in various physiological and pathological processes. Recently, noncoding RNAs were identified as key regulators in the development of atherosclerosis, including the dysfunction of endothelial cells, and vascular smooth muscle cells and it is pertinent to understand the potential function of noncoding RNAs in atherosclerosis development. In this review, the latest available research relates to the regulatory role of noncoding RNAs in the progression of atherosclerosis and the therapeutic potential for atherosclerosis is summarized. This review aims to provide a comprehensive overview of the regulatory and interventional roles of ncRNAs in atherosclerosis and to inspire new insights for the prevention and treatment of this disease.

HAND2-AS1 associates with outcomes of acute coronary syndrome and regulates cell viability of vascular endothelial cells

OBJECTIVE

Acute coronary syndrome (ACS) is an emergency and severe disorder of the cardiovascular system. This paper assessed the expression of plasma HAND2-AS1 in patients with ACS, researched its diagnostic and prognostic significance, and studied its possible mechanism for participating in ACS.

METHODS

The concentration of HAND2-AS1 of 101 included patients with ACS was certified by qRT-PCR and its possible diagnostic function was revealed by the receiver operating characteristic (ROC) curve. All patients were followed up for 6 months after percutaneous coronary intervention (PCI) therapy and Kaplan-Meier (K-M) curve and COX regression analysis was performed to estimate the short-term prognostic value of HAND2-AS1 in ACS. The interrelationship between HAND2-AS1 and Gensini score and endothelial injury was identified via Pearson correlation. The function of HAND2-AS1 on the viability, migration, and apoptosis of human umbilical vein endothelial cells (HUVECs) was estimated by the Cell Counting Kit-8 (CCK-8), Transwell chamber, and flow cytometry.

RESULTS

In ACS patients, the expression of serum HAND2-AS1 was prominently decreased and closely correlated with the Gensini score. The decreased HAND2-AS1 expression was of diagnostic significance. Declined plasma HAND2-AS1 was observed in patients with the major adverse cardio-cerebrovascular event (MACCE) and was an independent risk for the poor prognosis of ACS patients. In the cell model, upregulation of HAND2-AS1 improved cell viability and migration and inhibited cell apoptosis.

CONCLUSION

HAND2-AS1 was an independent biomarker for the diagnosis and prognosis of ACS. HAND2-AS1 might be involved in ACS development by regulating endothelial damage.

Severity of coronary artery disease is associated with diminished circANRIL expression: A possible blood based transcriptional biomarker in East Africa

Antisense Noncoding RNA in the INK4 Locus (ANRIL) is the prime candidate gene at Chr9p21, the well-defined genetic risk locus associated with coronary artery disease (CAD). ANRIL and its transcript variants were investigated for the susceptibility to CAD in adipose tissues (AT) and peripheral blood mononuclear cells (PBMCs) of the study group and the impact of 9p21.3 locus mutations was further analysed. Expressions of ANRIL, circANRIL (hsa_circ_0008574), NR003529, EU741058 and DQ485454 were detected in epicardial AT (EAT) mediastinal AT (MAT), subcutaneous AT (SAT) and PBMCs of CAD patients undergoing coronary artery bypass grafting and non-CAD patients undergoing heart valve surgery. ANRIL expression was significantly upregulated, while the expression of circANRIL was significantly downregulated in CAD patients. Decreased circANRIL levels were significantly associated with the severity of CAD and correlated with aggressive clinical characteristics. rs10757278 and rs10811656 were significantly associated with ANRIL and circANRIL expressions in AT and PBMCs. The ROC-curve analysis suggested that circANRIL has high diagnostic accuracy (AUC: 0.9808, cut-off: 0.33, sensitivity: 1.0, specificity: 0.88). circANRIL has high diagnostic accuracy (AUC: 0.9808, cut-off: 0.33, sensitivity: 1.0, specificity: 0.88). We report the first data demonstrating the presence of ANRIL and its transcript variants expressions in the AT and PBMCs of CAD patients. circANRIL having a synergetic effect with ANRIL plays a protective role in CAD pathogenesis. Therefore, altered circANRIL expression may become a potential diagnostic transcriptional biomarker for early CAD diagnosis.

Lnc-ANRIL modulates the immune response associated with NF-κB pathway in LPS-stimulated bovine mammary epithelial cells

BACKGROUND

The antisense noncoding RNA in the INK4 locus (ANRIL) has been confirmed related to multiple disease progression, but the role and exact mechanisms of lnc-ANRIL in lipopolysaccharide (LPS)-induced inflammation of bovine mammary epithelial cells (MAC-T) remain unclear.

AIMS

This manuscript focused on expounding the functional role of lnc-ANRIL through experiments performed in MAC-T.

METHODS

At the in vitro level, we established a Bovine mammary epithelial cell (BMEC) cell model of mastitis by LPS treatment. Transfection of siRNA was examined by immunofluorescence localization and RT-qPCR. CCK8, clonogenic assay and EdU were used to detect the proliferation ability of the cells. Cell cycle and apoptosis were detected by flow cytometry and Western blot. The levels of inflammatory factors and oxidative stress markers were detected by ELISA kits.

RESULTS

Cell Counting Kit-8, colony formation, and 5-ethynyl-20-deoxyuridine were adopted and the data illustrated that LPS could significantly suppress the cell proliferation, while knockdown of lnc-ANRIL expression obviously promoted MAC-T cell proliferation compared with LPS or LPS + si-NC group. Flow cytometry analysis demonstrated that lnc-ANRIL could induce MAC-T cell apoptosis. In addition, downregulation of lnc-ANRIL affected LPS-induced immune response by regulating inflammatory factor expressions and modulating the nuclear factor kappa B (NF-κB) axis in MAC-T cells.

CONCLUSION

Our results suggest that lnc-ANRIL is involved in the regulation of cell proliferation, cell cycle, and cell apoptosis of MAC-T cells, and plays an important role in the inflammatory and immune response of MAC-T cells through the regulation of the NF-κB pathway, proposing new therapeutic strategies for the treatment of innate immune response-related disease such as bovine mastitis.

Epigenetic Regulation of Angiogenesis in Peripheral Artery Disease

Peripheral arterial disease (PAD) represents a global health concern with a rising prevalence attributed to factors such as obesity, diabetes, aging, and smoking. Among patients with PAD, chronic limb-threatening ischemia (CLTI) is the most severe manifestation, associated with substantial morbidity and mortality. While revascularization remains the primary therapy for CLTI, not all patients are candidates for such interventions, highlighting the need for alternative approaches. Impaired angiogenesis, the growth of new blood vessels, is a central feature of PAD, and despite decades of research, effective clinical treatments remain elusive. Epigenetics, the study of heritable changes in gene expression, has gained prominence in understanding PAD pathogenesis. Here, we explore the role of epigenetic regulation in angiogenesis within the context of PAD, with a focus on long non-coding RNAs and fibroblast-endothelial cell transdifferentiation. Additionally, we discuss the interplay between metabolic control and epigenetic regulation, providing insights into potential novel therapeutic avenues for improving PAD treatments. This review aims to offer a concise update on the application of epigenetics in angiogenesis and PAD research, inspiring further investigations in this promising field.

Pharmacological roles of lncRNAs in diabetic retinopathy with a focus on oxidative stress and inflammation

Diabetic retinopathy (DR) is a complication caused by abnormal glucose metabolism, which affects the vision and quality of life of patients and severely impacts the society at large.DR has a complex pathogenic process. Evidence from multiple studies have shown that oxidative stress and inflammation play pivotal roles in DR.Additionally, with the rapid development of various genetic detection methods, the abnormal expression of long non-coding RNAs (lncRNAs) have been confirmed to promote the development of DR.Research has demonstrated the potential of lncRNAs as ideal biomarkers and theranostic targets in DR. In this narrative review, we will focus on the research results on mechanisms underlying DR, list lncRNAs confirmed to be closely related to these mechanisms, and discuss their potential clinical application value and limitations.

LINC00926 is involved in hypoxia-induced vascular endothelial cell dysfunction via miR-3194-5p regulating JAK1/STAT3 signaling pathway

Vascular endothelial cell (VEC) dysfunction is associated with the development of coronary heart disease (CHD). Long intergenic non-protein coding RNA 926 (LINC00926), a kind of long noncoding RNA (lncRNA), has been found to be abnormally expressed in CHD patients. However, the biological role of LINC00926 has not been reported. In our research, we intended to explore the regulatory mechanism of LINC00926 in hypoxia-exposed HUVEC cells (HUVECs). In our in vitro study, HUVECs were exposed under hypoxic conditions (5% O2) for 24 h. RT-qPCR and Western blotting assay were used to detect the mRNA and protein levels. CCK-8 assay, flow cytometry, transwell assay and in vitro angiogenesis assay were performed to measure cell proliferation, apoptosis, migration and tube formation, respectively. Bioinformatics analysis was applied to predict the target of LINC00926 and miR-3194-5p, which was verified by dual-luciferase reporter assays. The results showed that LINC00926 was highly expressed in CHD patients and hypoxia-exposed HUVECs. LINC00926 overexpression suppressed cell proliferation, migration and tube formation and increased cell apoptosis. MiR-3194-5p was a target of LINC00926 and can target binding to JAK1 3'UTR. LINC00926 could up-regulate JAK1 and p-STAT3 levels via miR-3194-5p. In addition, overexpressed LINC00926 suppressed cell proliferation, migration and tube formation and increased cell apoptosis via miR-3194-5p/JAK1/STAT3 axis. In summary, LINC00926 aggravated endothelial cell dysfunction via miR-3194-5p regulating JAK1/STAT3 signaling pathway in hypoxia-exposed HUVECs.

High-Phosphate-Stimulated Macrophage-Derived Exosomes Promote Vascular Calcification via let-7b-5p/TGFBR1 Axis in Chronic Kidney Disease

Although macrophage infiltration has been proven to increase calcified artery media in chronic kidney disease (CKD) patients, the mechanism by which macrophages are involved in vascular calcification (VC) progression remains unclear. Taking advantage of miRNA-seq, RNA-seq, dual-luciferase reporter assay, qRT-PCR, and arteries from CKD patients as well as CKD mouse models, we identified that high-phosphate-stimulated macrophage-derived exosomes (Mexo-P) suppressed let-7b-5p expression in VSMCs, which further upregulated TGFBR1. Moreover, gain-and-loss-of-function assays were used to determine the regulatory effects and downstream mechanism of let-7b-5p and TGFBR1 on VC. Mechanically, Mexo-P induced VSMC TGFBR1 upregulation by suppressing let-7b-5p, which further amplifies SMAD3/RUNX2 signaling and thereby contributes to VC. Our findings indicate that macrophage-derived exosomes promote CKD-associated VC through the let-7b-5p/TGFBR1 axis in high-phosphate conditions. Our study provides insight into macrophages associated with VC, which might be potential therapeutical targets for VC.

ANRIL overexpression globally induces expression and alternative splicing of genes involved in inflammation in HUVECs

Long non‑coding (lnc)RNAs serve important cellular functions and certain lncRNAs have roles in different mechanisms of gene regulation. lncRNA‑antisense non‑coding RNA in the INK4 locus (ANRIL) affects cell inflammation; however, the potential genes underlying the inflammatory response regulated by ANRIL remain unclear. In the present study, the potential function of ANRIL in regulating gene expression and alternative splicing was assessed. ANRIL‑regulated human umbilical vein endothelial cell (HUVEC) transcriptome was obtained using high‑throughput RNA sequencing (RNA‑seq) to evaluate the potential role of ANRIL. Following plasmid transfection, gene expression profile and alternative splicing pattern of HUVECs overexpressing ANRIL were analyzed using RNA‑seq. ANRIL overexpression affected the transcription levels of genes associated with the inflammatory response, NF‑κB signaling pathway, type I interferon‑mediated signal transduction pathway and innate immune response. ANRIL regulated the alternative splicing of hundreds of genes with functions such as gene expression, translation, DNA repair, RNA processing and participation in the NF‑κB signaling pathway. Many of these genes serve a key role in the inflammatory response. ANRIL‑regulated inflammatory response may be achieved by regulating alternate splicing and transcription. The present study broadened the understanding of ANRIL‑mediated gene regulation mechanisms and clarified the role of ANRIL in mediating inflammatory response mechanisms.

New developments in non-exosomal and exosomal ncRNAs in coronary artery disease

Aim & methods: Non-exosomal and exosomal ncRNAs have been reported to be involved in the regulation of coronary artery disease (CAD). Therefore, to explore the biological effects of non-exosomal/exosomal ncRNAs in CAD, the authors searched for studies published in the last 3 years on these ncRNAs in CAD and summarized their functions and mechanisms. Results: The authors summarized 120 non-exosomal ncRNAs capable of regulating CAD progression. In clinical studies, 47 non-exosomal and nine exosomal ncRNAs were able to serve as biomarkers for the diagnosis of CAD. Conclusion: Non-exosomal/exosomal ncRNAs are not only able to serve as biomarkers for CAD diagnosis but can also regulate CAD progression through ceRNA mechanisms and are a potential target for early clinical intervention in CAD.

LncRNA ANRIL-mediated miR-181b-5p/S1PR1 axis is involved in the progression of uremic cardiomyopathy through activating T cells

This study aimed to explore the regulatory role of lncRNA ANRIL/miR-181b-5p/S1PR1 in UC. UC mouse model was established by 5/6th nephrectomy. We detected body weight, serum levels of renal function and inflammatory factors (biochemical analyzer/ELISA), and cardiac parameters (echocardiography). HE and Masson staining showed the pathological changes and fibrosis in myocardial and nephridial tissues. The expression of ANRIL, miR-181b-5p, and S1PR1 were detected by qRT-PCR or Western blot/immunofluorescence. T cells activation was analyzed by Flow cytometry. ANRIL/S1PR1 were up-regulated and miR-181b-5p was down-regulated in UC mice. ANRIL silencing up-regulated miR-181b-5p and down-regulated S1PR1 (a target of miR-181b-5p). ANRIL silencing increased the body weight, recovered renal function [decreased blood urea nitrogen (BUN) and serum creatinine (Scr)] and cardiac function [decreased left ventricular end-diastolic diameter (LVEDD), LV end-systolic diameter (LVESD), LV systolic anterior wall thickness (LVAWS), LV end-diastolic anterior wall thickness (LVAWD), myocardial performance index (MPI), and isovolumic relaxation time (IVRT); increased LV ejection fraction (LVEF), LVEF/MPI, fractional shortening (FS), and E- and A-waves (E/A)], inhibited the inflammation [decreased interferon (IFN)-γ, interleukin (IL)-2, IL-10, and tumor necrosis factor (TNF)-α], and relieved pathological injuries and fibrosis. ANRIL silencing also recovered the viability and inhibited the inflammation of activated T cells in vitro, and inhibited T cell activation in UC mice in vivo. In addition, miR-181b-5p overexpression exhibited same effects with ANRIL silencing in UC. ANRIL silencing inhibited T cell activation through regulating miR-181b-5p/S1PR1, contributing to the remission of UC.

Mettl14 mediates the inflammatory response of macrophages in atherosclerosis through the NF-κB/IL-6 signaling pathway

The inflammatory response of macrophages has been reported to play a critical role in atherosclerosis. The inflammatory state of macrophages is modified by epigenetic reprogramming. m⁶A RNA methylation is an epigenetic modification of RNAs. However, little is known about the potential roles and underlying mechanisms of m⁶A modification in macrophage inflammation. Herein, we showed that the expression of the m⁶A modification “writer” Mettl14 was increased in coronary heart disease and LPS-stimulated THP-1 cells. Knockdown of Mettl14 promoted M2 polarization of macrophages, inhibited foam cell formation and decreased migration. Mechanistically, the expression of Myd88 and IL-6 was decreased in Mettl14 knockdown cells. Through m⁶A modification, Mettl14 regulated the stability of Myd88 mRNA. Furthermore, Myd88 affected the transcription of IL-6 via the distribution of p65 in nuclei rather than directly regulating the expression of IL-6 through m⁶A modification. In vivo, Mettl14 gene knockout significantly reduced the inflammatory response of macrophages and the development of atherosclerotic plaques. Taken together, our data demonstrate that Mettl14 plays a vital role in macrophage inflammation in atherosclerosis via the NF-κB/IL-6 signaling pathway, suggesting that Mettl14 may be a promising therapeutic target for the clinical treatment of atherosclerosis.

Targeting Circulating lncRNA ENST00000538705.1 Relieves Acute Coronary Syndrome via Modulating ALOX15

Objective

Acute coronary syndrome (ACS) is the most dangerous and deadly form of coronary heart disease. Herein, we aimed to explore ACS-specific circulating lncRNAs and their regulatory mechanisms.

Methods

This study collected serum samples from ACS patients and healthy controls for microarray analysis. Dysregulated circulating lncRNAs and mRNAs were determined with |log2fold − change| > 1 and p < 0.05. lncRNA-mRNA coexpression analysis was carried out. ENST00000538705.1 and ALOX15 expression was further verified in serum specimens. In human coronary artery endothelial cells (HCAECs), ENST00000538705.1 and ALOX15 were knocked out through transfecting specific siRNAs. Thereafter, proliferation and migration were investigated with CCK-8 and wound-healing assays. Myocardial infarction rat models were established and administrated with siRNAs against ENST00000538705.1 or ALOX15. Myocardial damage was investigated with H&E staining, and serum TC, LDL, and HDL levels were measured.

Results

Microarray analysis identified 353 dysregulated circulating lncRNAs and 441 dysregulated circulating mRNAs in ACS. Coexpression analysis indicated the interaction between ENST00000538705.1 and ALOX15. RT-qPCR confirmed the remarkable upregulation of circulating ENST00000538705.1 and ALOX15 in ACS patients. In HCAECs, ENST00000538705.1 knockdown lowered the expression of ALOX15 but ALOX15 did not alter the expression of ENST00000538705.1. Silencing ENST00000538705.1 or ALOX15 weakened the proliferation and migration of HCAECs. Additionally, knockdown of ENST00000538705.1 or ALOX15 relieved myocardial damage, decreased serum TC and LDL levels, and elevated HDL levels in myocardial infarction rats.

Conclusion

Collectively, our findings demonstrate that circulating ENST00000538705.1 facilitates ACS progression through modulating ALOX15, which provide potential targets for ACS treatment.

The Role of ANRIL in Atherosclerosis

There is a huge number of noncoding RNA (ncRNA) transcripts in the cell with important roles in modulation of different mechanisms. ANRIL is a long ncRNA with 3.8 kb length that is transcribed in the opposite direction of the INK4/ARF locus in chromosome 9p21. It was shown that polymorphisms within this locus are associated with vascular disorders, notably coronary artery disease (CAD), which is considered as a risk factor for life-threatening events like myocardial infarction and stroke. ANRIL is subjected to a variety of splicing patterns producing multiple isoforms. Linear isoforms could be further transformed into circular ones by back-splicing. ANRIL regulates genes in atherogenic network in a positive or negative manner. This regulation is implemented both locally and remotely. While CAD is known as a proliferative disorder and cell proliferation plays a crucial role in the progression of atherosclerosis, the functions of ANRIL and CAD development are intertwined remarkably. This makes ANRIL a suitable target for diagnostic, prognostic, and even therapeutic aims. In this review, we tried to present a comprehensive appraisal on different aspects of ANRIL including its location, structure, isoforms, expression, and functions. In each step, the contribution of ANRIL to atherosclerosis is discussed.

Roles and functions of antisense lncRNA in vascular aging

Vascular aging is a major cause of morbidity and mortality in the elderly population. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), forming the intima and media layers of the vessel wall respectively, are closely associated with the process of vascular aging and vascular aging-related diseases. Numerous studies have revealed the pathophysiologic mechanism through which lncRNA contributes to vascular aging, hence more attention is now paid to the role played by antisense long non-coding RNA (AS-lncRNA) in the pathogenesis of vascular aging. Nonetheless, only a small number of studies focus on the specific mechanism through which AS-lncRNA mediates vascular aging. In this review, we summarize the roles and functions of AS-lncRNA with regards to the development of vascular aging and vascular aging-related disease. We also aim to deepen our understanding of this process and provide alternative therapeutic modalities for vascular aging-related diseases.

Epigenetic Regulation of Endothelial Dysfunction and Inflammation in Pulmonary Arterial Hypertension

Once perceived as a disorder treated by vasodilation, pulmonary artery hypertension (PAH) has emerged as a pulmonary vascular disease with severe endothelial cell dysfunction. In the absence of a cure, many studies seek to understand the detailed mechanisms of EC regulation to potentially create more therapeutic options for PAH. Endothelial dysfunction is characterized by complex phenotypic changes including unchecked proliferation, apoptosis-resistance, enhanced inflammatory signaling and metabolic reprogramming. Recent studies have highlighted the role of epigenetic modifications leading to pro-inflammatory response pathways, endothelial dysfunction, and the progression of PAH. This review summarizes the existing literature on epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNAs, which can lead to aberrant endothelial function. Our goal is to develop a conceptual framework for immune dysregulation and epigenetic changes in endothelial cells in the context of PAH. These studies as well as others may lead to advances in therapeutics to treat this devastating disease.

LncRNA ANRIL Facilitates Vascular Smooth Muscle Cell Proliferation and Suppresses Apoptosis via Modulation of miR-7/FGF2 Pathway in Intracranial Aneurysms

BACKGROUND

Proliferation and apoptosis of vascular smooth muscle cells (VSMCs) are linked to intracranial aneurysm (IA) formation and progression. Long antisense noncoding RNA in the INK4 locus (ANRIL) has been reported to regulate VSMC functions in several cardiovascular diseases. However, little is known about how ANRIL influences VSMC proliferation and apoptosis during IA pathogenesis.

METHODS

The expression level of ANRIL in the plasma and arterial wall tissues of patients with IA was detected by real-time quantitative polymerase chain reaction. The functional role of ANRIL in the regulation of VSMC proliferation and apoptosis and its downstream regulatory mechanism were determined using Cell Counting Kit 8, immunofluorescence, terminal-deoxynucleotidyl transferase-mediated UTP nick end labeling, western blotting, luciferase reporter assay, and RNA immunoprecipitation assay.

RESULTS

ANRIL was downregulated in the plasma and arterial wall tissues of patients with IA, when compared with control groups. Overexpression of ANRIL significantly promoted VSMC proliferation and blocked cell apoptosis. Mechanistic studies demonstrated that ANRIL directly bound to microRNA-7 (miR-7) and that overexpression of miR-7 overturned the increased cell proliferation and decreased cell apoptosis, which was induced by ANRIL restoration. Besides, further study showed that ANRIL positively regulated fibroblast growth factor 2 (FGF2) expression via targeting miR-7.

CONCLUSIONS

These results suggested that ANRIL affects VSMC proliferation and apoptosis via regulation of the miR-7/FGF2 pathway in IA, which provided a potential novel strategy for the treatment of IA.

The role of let-7b in the inhibition of hepatic stellate cell activation by rSjP40

BACKGROUND

Hepatic stellate cells (HSCs) are one of the main cell types involved in liver fibrosis induced by many factors, including schistosomes. Previous studies in our lab have shown that recombinant P40 protein from Schistosoma japonicum (rSjP40) can inhibit HSC activation in vitro. Let-7b is a member of the let-7 microRNA family and plays an inhibitory role in a variety of diseases and inflammatory conditions. In this study, we investigated the role of let-7b in the inhibition of HSC activation by rSjP40.

METHODS

Expression of let-7b was detected by quantitative real-time PCR. A dual luciferase assay was used to confirm direct interaction between let-7b and collagen I. We also used western blot to assess protein levels of TGFβRI and collagen type I α1 (COL1A1).

RESULTS

We found that rSjP40 up-regulates expression of let-7b in HSCs. Let-7b inhibits collagen I expression by directly targeting the 3'UTR region of the collagen I gene. Furthermore, we discovered that let-7b inhibitor partially restores the loss of collagen I expression caused by rSjP40.

CONCLUSION

Our research clarifies the role of let-7b in the inhibition of HSC activation by rSjP40 and will provide new insights and ideas for the inhibition of HSC activation and treatment of liver fibrosis.

The Role of Long Non-coding RNAs in Sepsis-Induced Cardiac Dysfunction

Sepsis is a syndrome with life-threatening organ dysfunction induced by a dysregulated host response to infection. The heart is one of the most commonly involved organs during sepsis, and cardiac dysfunction, which is usually indicative of an extremely poor clinical outcome, is a leading cause of death in septic cases. Despite substantial improvements in the understanding of the mechanisms that contribute to the origin and responses to sepsis, the prognosis of sepsis-induced cardiac dysfunction (SICD) remains poor and its molecular pathophysiological changes are not well-characterized. The recently discovered group of mediators known as long non-coding RNAs (lncRNAs) have presented novel insights and opportunities to explore the mechanisms and development of SICD and may provide new targets for diagnosis and therapeutic strategies. LncRNAs are RNA transcripts of more than 200 nucleotides with limited or no protein-coding potential. Evidence has rapidly accumulated from numerous studies on how lncRNAs function in associated regulatory circuits during SICD. This review outlines the direct evidence of the effect of lncRNAs on SICD based on clinical trials and animal studies. Furthermore, potential functional lncRNAs in SICD that have been identified in sepsis studies are summarized with a proven biological function in research on other cardiovascular diseases.

The Emerging Role of Long Non-coding RNAs and Circular RNAs in Coronary Artery Disease

Coronary artery disease (CAD) is a common disorder caused by atherosclerotic processes in the coronary arteries. This condition results from abnormal interactions between numerous cell types in the artery walls. The main participating factors in this process are accumulation of lipid deposits, endothelial cell dysfunction, macrophage induction, and changes in smooth muscle cells. Several lines of evidence underscore participation of long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) in the pathogenesis of CAD. Several lncRNAs such as H19, ANRIL, MIAT, lnc-DC, IFNG-AS1, and LEF1-AS1 have been shown to be up-regulated in the biological materials obtained from CAD patients. On the other hand, Gas5, Chast, HULC, DICER1-AS1, and MEG3 have been down-regulated in CAD patients. Meanwhile, a number of circRNAs have been demonstrated to influence function of endothelial cells or vascular smooth muscle cells, thus contributing to the pathogenesis of CAD. In the current review, we summarize the function of lncRNAs and circRNAs in the development and progression of CAD.

Oxidized LDL Causes Endothelial Apoptosis by Inhibiting Mitochondrial Fusion and Mitochondria Autophagy

Oxidized low-density lipoprotein (ox-LDL)-induced endothelial dysfunction is an initial step toward atherosclerosis development. Mitochondria damage correlates with ox-LDL-induced endothelial injury through an undefined mechanism. We explored the role of optic atrophy 1 (Opa1)-related mitochondrial fusion and mitophagy in ox-LDL-treated endothelial cells, focusing on mitochondrial damage and cell apoptosis. Oxidized low-density lipoprotein treatment reduced endothelial cell viability by increasing apoptosis. Endothelial cell proliferation and migration were also impaired by ox-LDL. At the molecular level, mitochondrial dysfunction was induced by ox-LDL, as demonstrated by decreased mitochondrial membrane potential, increased mitochondrial reactive oxygen species production, augmented mitochondrial permeability transition pore openings, and elevated caspase-3/9 activity. Mitophagy and mitochondrial fusion were also impaired by ox-LDL. Opa1 overexpression reversed this effect by increasing endothelial cell viability and decreasing apoptosis. Interestingly, inhibition of mitophagy or mitochondrial fusion through transfection of siRNAs against Atg5 or Mfn2, respectively, abolished the protective effects of Opa1. Our results illustrate the role of Opa1-related mitochondrial fusion and mitophagy in sustaining endothelial cell viability and mitochondrial homeostasis under ox-LDL stress.