circRNA CDR1as Promotes Pulmonary Artery Smooth Muscle Cell Calcification by Upregulating CAMK2D and CNN3 via Sponging miR-7-5p

RNA m6A methylation and regulatory proteins in pulmonary arterial hypertension

m6A (N6‑methyladenosine) is the most common and abundant apparent modification in mRNA of eukaryotes. The modification of m6A is regulated dynamically and reversibly by methyltransferase (writer), demethylase (eraser), and binding protein (reader). It plays a significant role in various processes of mRNA metabolism, including regulation of transcription, maturation, translation, degradation, and stability. Pulmonary arterial hypertension (PAH) is a malignant cardiopulmonary vascular disease characterized by abnormal proliferation of pulmonary artery smooth muscle cells. Despite the existence of several effective and targeted therapies, there is currently no cure for PAH and the prognosis remains poor. Recent studies have highlighted the crucial role of m6A modification in cardiovascular diseases. Investigating the role of RNA m6A methylation in PAH could provide valuable insights for drug development. This review aims to explore the mechanism and function of m6A in the pathogenesis of PAH and discuss the potential targeting of RNA m6A methylation modification as a treatment for PAH.

CircALMS1 Alleviates Pulmonary Microvascular Endothelial Cell Dysfunction in Pulmonary Hypertension

BACKGROUND

Circular RNAs can serve as regulators influencing the development of pulmonary hypertension (PH). However, their function in pulmonary vascular intimal injury remains undefined. Thus, we aimed to identify specifically expressed circular RNAs in pulmonary microvascular endothelial cells (PMECs) under hypoxia and PH.

METHODS AND RESULTS

Deep RNA sequencing and quantitative real-time polymerase chain reaction revealed that circALMS1 (circular RNA Alstrom syndrome protein 1) was reduced in human PMECs under hypoxia (P<0.0001). Molecular biology and histopathology experiments were used to elucidate the roles of circALMS1 in regulating PMEC dysfunction among patients with PH. The circALMS1 expression was decreased in the plasma of patients with PH (P=0.0315). Patients with lower circALMS1 levels had higher risk of death (P=0.0006). Moreover, the circALMS1 overexpression of adeno-associated viruses improved right ventricular function and reduced pulmonary vascular remodeling in monocrotaline-PH and sugen/hypoxia-PH rats (P<0.05). Furthermore, circALMS1 overexpression promoted apoptosis and inhibited PMEC proliferation and migration under hypoxia by directly downregulating miR-17-3p (P<0.05). Dual luciferase assay confirmed the direct binding of circALMS1 to miR-17-3p and miR-17-3p binding to its target gene YT521-B homology domain-containing family protein 2 (YTHDF2) (P<0.05). The YTHDF2 levels were also downregulated in hypoxic PMECs (P<0.01). The small interfering RNA YTHDF2 reversed the effects of miR-17-3p inhibitors on PMEC proliferation, migration, and apoptosis. Finally, the results indicated that, although YTHDF2, as an N(6)-methyladenosine reader protein, contributes to the degradation of many circular RNAs, it could not regulate the circALMS1 levels in PMECs (P=0.9721).

CONCLUSIONS

Our study sheds new light on circALMS1-regulated dysfunction of PMECs by the miR-17-3p/YTHDF2 pathway under hypoxia and provides insights into the underlying pathogenesis of PH.

Exosomes From IgE-Stimulated Mast Cells Aggravate Asthma-Mediated Atherosclerosis Through circRNA CDR1as-Mediated Endothelial Cell Dysfunction in Mice

BACKGROUND

IgE has been known for mediating endothelial cell dysfunction and mast cell (MC) activation to fuel asthma-aggravated high-fat diet-induced atherosclerosis. However, it remains unclear for the mechanism of asthma-mediated atherosclerosis, especially the potential involvement of IgE in the exacerbation of asthma-mediated atherosclerosis with a standard laboratory diet, and the cross talk between endothelial cells and MCs.

METHODS

Asthma-mediated atherosclerosis mice models under a standard laboratory diet and FcεR1 knock-out mice were used to determine the role of IgE-FcεR1 signaling in asthma-mediated atherosclerosis, which was assessed by Oil Red O staining and immunohistochemistry. Various in vitro assays including nanoparticle tracking analysis and transmission electron microscopy were used to evaluate exosome characteristics. Immunofluorescence and fluorescent in situ hybridization approaches were used to evaluate the effect and mechanism of MC-secreted exosomes encapsulated circular RNA CDR1as (cerebellar degeneration-related 1 antisense) on endothelial cells in vivo and in vitro. Finally, cohort studies examined the plasma CDR1as levels in patients with atherosclerosis with or without allergies.

RESULTS

Asthma mice with a standard laboratory diet showed increased atherosclerotic lesions and inflammatory infiltration depending on IgE-FcεR1 signal. FcεR1 knockout mice and blockage of IgE-FcεR1 signaling with IgE monoclonal antibody, omalizumab, all significantly alleviated asthma-mediated atherosclerosis and vascular inflammatory remodeling. Anti-inflammation with dexamethasone and stabilization of MC with cromolyn partially alleviated atherosclerotic lesions and mitigated the inflammatory infiltration in arteries. Mechanistically, IgE stimulation upregulates MC CDR1as expression in exosomes and upregulates the endothelial cell adhesive factors VCAM-1 (vascular cell adhesion molecule-1) and ICAM-1 (intercellular adhesion molecule-1) via the CDR1as-FUS (fused in sarcoma)-phos-p65 axis. Knockdown of CDR1as in vivo significantly decreased the endothelial adhesion function and mitigated asthma-mediated atherosclerosis. Furthermore, a cohort study indicated higher plasma CDR1as levels in patients with atherosclerosis with allergies than in patients with atherosclerosis and healthy controls.

CONCLUSIONS

Exosomes from IgE-stimulated MCs aggravated atherosclerosis through circular RNA CDR1as-mediated endothelial dysfunction, providing a novel insight into asthma-mediated atherosclerosis and potential diagnostic and therapeutic targets.

Circular RNA: A new expectation for cardiovascular diseases

Circular RNA (circRNA) is a class of RNA with the 5' and 3' ends connected covalently to form a closed loop structure and characterized by high stability, conserved sequences and tissue specificity, which is caused by special reverse splicing methods. Currently, it has become a hot spot for research. With the discovery of its powerful regulatory functions and roles, the molecular mechanisms and future value of circRNA in participating in and regulating biological and pathological processes are becoming increasingly apparent. Among them is the increasing prevalence of cardiovascular diseases (CVDs). Many studies have elucidated that circRNA plays a crucial role in the development and progression of CVDs. Therefore, circRNA shows its advantages and brilliant expectations in the field of CVDs. In this review, we describe the biogenesis, bioinformatics detection and function of circRNA and discuss the role of circRNA and its effects on CVDs, including atherosclerosis, myocardial infarction, cardiac hypertrophy and heart failure, myocardial fibrosis, cardiac senescence, pulmonary hypertension, and diabetic cardiomyopathy by different mechanisms. That shows circRNA advantages and brilliant expectations in the field of CVDs.

Vascular calcification and cellular signaling pathways as potential therapeutic targets

Increased vascular calcification (VC) is observed in patients with cardiovascular diseases such as atherosclerosis, diabetes, and chronic kidney disease. VC is divided into three types according to its location: intimal, medial, and valvular. Various cellular signaling pathways are associated with VC, including the Wnt, mitogen-activated protein kinase, phosphatidylinositol-3 kinase/Akt, cyclic nucleotide-dependent protein kinase, protein kinase C, calcium/calmodulin-dependent kinase II, adenosine monophosphate-activated protein kinase/mammalian target of rapamycin, Ras homologous GTPase, apoptosis, Notch, and cytokine signaling pathways. In this review, we discuss the literature concerning the key cellular signaling pathways associated with VC and their role as potential therapeutic targets. Inhibitors to these pathways represent good candidates for use as potential therapeutic agents for the prevention and treatment of VC.

Exploring the Multifaceted Biologically Relevant Roles of circRNAs: From Regulation, Translation to Biomarkers

CircRNAs are a category of regulatory RNAs that have garnered significant attention in the field of regulatory RNA research due to their structural stability and tissue-specific expression. Their circular configuration, formed via back-splicing, results in a covalently closed structure that exhibits greater resistance to exonucleases compared to linear RNAs. The distinctive regulation of circRNAs is closely associated with several physiological processes, as well as the advancement of pathophysiological processes in several human diseases. Despite a good understanding of the biogenesis of circular RNA, details of their biological roles are still being explored. With the steady rise in the number of investigations being carried out regarding the involvement of circRNAs in various regulatory pathways, understanding the biological and clinical relevance of circRNA-mediated regulation has become challenging. Given the vast landscape of circRNA research in the development of the heart and vasculature, we evaluated cardiovascular system research as a model to critically review the state-of-the-art understanding of the biologically relevant functions of circRNAs. We conclude the review with a discussion of the limitations of current functional studies and provide potential solutions by which these limitations can be addressed to identify and validate the meaningful and impactful functions of circRNAs in different physiological processes and diseases.

MicroRNAs and their regulators: Potential therapeutic targets in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a complex and progressive disease characterized by pulmonary arterial remodeling. Despite that current combination therapy has shown improvement in morbidity and mortality, a better deciphering of the underlying pathological mechanisms and novel therapeutic targets is urgently needed to combat PAH. MicroRNA, the critical element in post-transcription mechanisms, mediates cellular functions mainly by tuning downstream target gene expression. Meanwhile, upstream regulators can regulate miRNAs in synthesis, transcription, and function. In vivo and in vitro studies have suggested that miRNAs and their regulators are involved in PAH. However, the miRNA-related regulatory mechanisms governing pulmonary vascular remodeling and right ventricular dysfunction remain elusive. Hence, this review summarized the controversial roles of miRNAs in PAH pathogenesis, focused on different miRNA-upstream regulators, including transcription factors, regulatory networks, and environmental stimuli, and finally proposed the prospects and challenges for the therapeutic application of miRNAs and their regulators in PAH treatment.

ADAR1 regulates vascular remodeling in hypoxic pulmonary hypertension through N1-methyladenosine modification of circCDK17

Pulmonary hypertension (PH) is an extremely malignant pulmonary vascular disease of unknown etiology. ADAR1 is an RNA editing enzyme that converts adenosine in RNA to inosine, thereby affecting RNA expression. However, the role of ADAR1 in PH development remains unclear. In the present study, we investigated the biological role and molecular mechanism of ADAR1 in PH pulmonary vascular remodeling. Overexpression of ADAR1 aggravated PH progression and promoted the proliferation of pulmonary artery smooth muscle cells (PASMCs). Conversely, inhibition of ADAR1 produced opposite effects. High-throughput whole transcriptome sequencing showed that ADAR1 was an important regulator of circRNAs in PH. CircCDK17 level was significantly lowered in the serum of PH patients. The effects of ADAR1 on cell cycle progression and proliferation were mediated by circCDK17. ADAR1 affects the stability of circCDK17 by mediating A-to-I modification at the A5 and A293 sites of circCDK17 to prevent it from m1A modification. We demonstrate for the first time that ADAR1 contributes to the PH development, at least partially, through m1A modification of circCDK17 and the subsequent PASMCs proliferation. Our study provides a novel therapeutic strategy for treatment of PH and the evidence for circCDK17 as a potential novel marker for the diagnosis of this disease.

CircHIPK3 relieves vascular calcification via mediating SIRT1/PGC-1α/MFN2 pathway by interacting with FUS

BACKGROUND

Circular RNAs (circRNAs) have been reported to regulate the biological processes of human diseases. CircHIPK3 has been implicated in vascular calcification, but the downstream regulatory mechanisms remain unclear. Our study aimed to understand the regulatory function of circHIPK3 in vascular calcification.

METHODS

CircHIPK3 expression in atherosclerosis (AS) serum samples and vascular smooth muscle cells (VSMCs) calcification model was assessed by quantitative real-time polymerase chain reaction (qRT-PCR). The binding relationships between fused in sarcoma (FUS) and circHIPK3 or sirtuin 1 (SIRT1) were verified by RNA immunoprecipitation (RIP) assay and RNA pull-down assays. Alkaline phosphatase (ALP) activity and alizarin red staining assays were performed to evaluate the biological effect of β-glycerophosphate (β-GP) and circHIPK3 on calcium deposition. qRT-PCR and western blot assays were used to examine the effect of β-GP, circHIPK3, SIRT1, mitofusin 2 (MFN2), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) on VSMCs calcification and the expression of calcification-related proteins.

RESULTS

In AS serum samples and VSMCs calcification model, the expression of circHIPK3 was significantly reduced. CircHIPK3 overexpression inhibited ALP activity and calcium deposition in β-GP-induced VSMCs. Moreover, circHIPK3 could recruit FUS to further stabilize SIRT1 mRNA. CircHIPK3 promoted MFN2 expression to alleviate VSMCs calcification via activating SIRT1/PGC-1α signaling.

CONCLUSION

The positive regulation of circHIPK3/FUS/SIRT1/PGC-1α/MFN2 signaling pathway contributed to the alleviate VSMCs calcification, revealing a novel regulatory axis for vascular calcification.

The role of CDR1as/ciRS-7 in cardio-cerebrovascular diseases

Cerebellar degeneration-related protein 1 antisense RNA (CDR1as), also known as ciRS-7, is a circular natural antisense transcript of CDR1. It is a widely studied and powerful representative of circular RNAs. Based on its widely reported role in cancer, CDR1as is considered one of the most promising biomarkers for diagnosing and treating tumours. However, some recent studies have extensively focused on its regulatory role in cardio-cerebrovascular diseases instead of in tumours. Studies have shown that CDR1as plays a unique role in the occurrence of cardio-cerebrovascular diseases; thus, it may be a potential target for preventing and treating cardio-cerebrovascular diseases. Furthermore, CDR1as has also been found to be related to signal transduction pathways related to inflammatory response, oxidative stress, etc., which may reveal its potential mechanism in cardio-cerebrovascular diseases. However, there is no literature to summarize the role and possible mechanism of CDR1as in cardio-cerebrovascular diseases. Therefore, in the present review, we have comprehensively summarised the latest progress in the biological characteristics, development processes, regulatory mechanisms, and roles of CDR1as in cardio-cerebrovascular diseases, aiming to provide a reference and guidance for future studies.

Vascular calcification: from the perspective of crosstalk

Vascular calcification (VC) is highly correlated with cardiovascular disease morbidity and mortality, but anti-VC treatment remains an area to be tackled due to the ill-defined molecular mechanisms. Regardless of the type of VC, it does not depend on a single cell but involves multi-cells/organs to form a complex cellular communication network through the vascular microenvironment to participate in the occurrence and development of VC. Therefore, focusing only on the direct effect of pathological factors on vascular smooth muscle cells (VSMCs) tends to overlook the combined effect of other cells and VSMCs, including VSMCs-VSMCs, ECs-VMSCs, Macrophages-VSMCs, etc. Extracellular vesicles (EVs) are a collective term for tiny vesicles with a membrane structure that are actively secreted by cells, and almost all cells secrete EVs. EVs docked on the surface of receptor cells can directly mediate signal transduction or transfer their contents into the cell to elicit a functional response from the receptor cells. They have been proven to participate in the VC process and have also shown attractive therapeutic prospects. Based on the advantages of EVs and the ability to be detected in body fluids, they may become a novel therapeutic agent, drug delivery vehicle, diagnostic and prognostic biomarker, and potential therapeutic target in the future. This review focuses on the new insight into VC molecular mechanisms from the perspective of crosstalk, summarizes how multi-cells/organs interactions communicate via EVs to regulate VC and the emerging potential of EVs as therapeutic methods in VC. We also summarize preclinical experiments on crosstalk-based and the current state of clinical studies on VC-related measures.

Dynamic observation of circRNA and mRNA profiles in a rat model of deep vein thrombosis

The goal of the present study was to identify different transcriptome expression profiles involved in the pathogenesis of deep vein thrombosis (DVT), and to illustrate the diagnostic and therapeutic potential of circular RNAs (circRNAs) and mRNAs in DVT progression. A Sprague-Dawley rat model of DVT was successfully established through the stenosis method and samples were sequenced at four time points (1, 6 and 12 h, and 3 days after ligation) to observe the dynamic changes in circRNAs and mRNAs during DVT progression. RNA sequencing was used to analyze the circRNA and mRNA expression profiles, and associated functions and pathways, in the blood of DVT rats at the four time points. In addition, Short Time Series Expression Miner (STEM) analysis was performed to explore temporal gene expression. Differential expression of 1,680, 4,018, 3,724, and 3,036 circRNAs, and 400, 1,176, 373, and 573 mRNAs was observed in the 1, 6 and 12 h, and 3-day groups, respectively, compared with the sham group (fold change >2.0 or <-2.0, P<0.05). Functional enrichment analysis indicated that differentially expressed mRNAs were associated with the following terms: Immune response, cell activation, blood stasis facilitated organelle, extracellular membrane-bounded organelle, and blood microparticle, oxygen transporter activity. STEM analysis indicated that the expression of 366 circRNAs in circRNA profile 45 and 270 mRNAs in mRNA profile 45 was consistent with thrombus progression. Enrichment analysis was performed on mRNA profile 45. The main Gene Ontology annotations were chromosome segregation, mitotic sister chromatid segregation, cell cycle process, and ligand-dependent nuclear receptor transcription coactivator activity. Pathway enrichment analysis identified the platelet-associated pathway, immune-associated pathway, and inflammation-relation pathway. According to the enriched platelet-associated pathways, four mRNAs and ten candidate circRNAs were selected for reverse transcription-quantitative PCR verification. The expression of nine of the ten circRNAs and all four mRNAs was consistent with the sequencing results. In summary, differentially expressed circRNAs and mRNAs are dynamically involved in DVT development. Dysregulated transcriptome profiles and the corresponding functions and pathways may provide mechanistic insights into DVT diagnosis and treatment.

CDR1as promotes arrhythmias in myocardial infarction via targeting the NAMPT-NAD+ pathway

Cardiac ventricular arrhythmia triggered by acute myocardial infarction (AMI) is a major cause of sudden cardiac death. We have reported previously that an increased serum level of circular RNA CDR1as is a potential biomarker of AMI. However, the possible role of CDR1as in post-infarct arrhythmia remains unclear. This study in MI mice investigated the effects and underlying mechanism of CDR1as in ventricular arrhythmias associated with MI. We showed that knockdown of CDR1as abbreviated the duration of the abnormally prolonged QRS complex and QTc intervals and decreased susceptibility to ventricular arrhythmias. Optical mapping demonstrated knockdown of CDR1as also reduced post-infarct arrhythmia by increasing the conduction velocity and decreasing dispersion of repolarization. Mechanistically, CDR1as led to the depletion of NAD+ and caused mitochondrial dysfunction by directly targeting the NAMPT protein and repressing its expression. Moreover, CDR1as aggravated dysregulation of the NaV1.5 and Kir6.2 channels in cardiomyocytes, a change which was alleviated by the replenishment of NAD+. These findings suggest that anti-CDR1as is a potential therapeutic approach for ischemic arrhythmias.

Extracellular vesicles in atherosclerosis and vascular calcification: the versatile non-coding RNAs from endothelial cells and vascular smooth muscle cells

Atherosclerosis (AS) is characterized by the accumulation of lipids, fibrous elements, and calcification in the innermost layers of arteries. Vascular calcification (VC), the deposition of calcium and phosphate within the arterial wall, is an important characteristic of AS natural history. However, medial arterial calcification (MAC) differs from intimal calcification and cannot simply be explained as the consequence of AS. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are directly involved in AS and VC processes. Understanding the communication between ECs and VSMCs is critical in revealing mechanisms underlying AS and VC. Extracellular vesicles (EVs) are found as intercellular messengers in kinds of physiological processes and pathological progression. Non-coding RNAs (ncRNAs) encapsulated in EVs are involved in AS and VC, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). The effects of ncRNAs have not been comprehensively understood, especially encapsulated in EVs. Some ncRNAs have demonstrated significant roles in AS and VC, but it remains unclear the functions of the majority ncRNAs detected in EVs. In this review, we summarize ncRNAs encapsulated in EC-EVs and VSMC-EVs, and the signaling pathways that are involved in AS and VC.

Circular RNA as Therapeutic Targets in Atherosclerosis: Are We Running in Circles?

Much attention has been paid lately to harnessing the diagnostic and therapeutic potential of non-coding circular ribonucleic acids (circRNAs) and micro-RNAs (miRNAs) for the prevention and treatment of cardiovascular diseases. The genetic environment that contributes to atherosclerosis pathophysiology is immensely complex. Any potential therapeutic application of circRNAs must be assessed for risks, benefits, and off-target effects in both the short and long term. A search of the online PubMed database for publications related to circRNA and atherosclerosis from 2016 to 2022 was conducted. These studies were reviewed for their design, including methods for developing atherosclerosis and the effects of the corresponding atherosclerotic environment on circRNA expression. Investigated mechanisms were recorded, including associated miRNA, genes, and ultimate effects on cell mechanics, and inflammatory markers. The most investigated circRNAs were then further analyzed for redundant, disparate, and/or contradictory findings. Many disparate, opposing, and contradictory effects were observed across experiments. These include levels of the expression of a particular circRNA in atherosclerotic environments, attempted ascertainment of the in toto effects of circRNA or miRNA silencing on atherosclerosis progression, and off-target, cell-specific, and disease-specific effects. The high potential for detrimental and unpredictable off-target effects downstream of circRNA manipulation will likely render the practice of therapeutic targeting of circRNA or miRNA molecules not only complicated but perilous.

Insights into circular RNAs : Biogenesis, function and their regulatory roles in cardiovascular disease

As a distinctive member of the noncoding RNA family, circular RNAs (circRNAs) are generated from single-stranded, covalently closed structures and are ubiquitous in mammalian cells and tissues. Due to its atypical circular architecture, it was conventionally deemed insignificant dark matter for a prolonged duration. Nevertheless, studies conducted over the last decade have demonstrated that this abundant, structurally stable and tissue-specific RNA has been increasingly relevant in diverse diseases, including cancer, neurological disorders, diabetes mellitus and cardiovascular diseases (CVDs). Therefore, regulatory pathways controlled by circRNAs are widely involved in the occurrence and pathological processes of CVDs through their function as miRNA sponges, protein sponges and protein scaffolds. To better understand the role of circRNAs and their complex regulatory networks in CVDs, we summarize current knowledge of their biogenesis and function and the latest research on circRNAs in CVDs, with the hope of paving the way for the identification of promising biomarkers and therapeutic strategies for CVDs.

Methods to Study RNA-Chromatin Interactions

RNA plays a fundamental role in the organization of chromatin as well as the regulation of gene expression. Although the chromatin is pervasively attached by both coding and noncoding RNAs, the impact of these chromatin-associated RNAs (caRNAs) on gene expression and cellular functions and their underlying mechanisms have just begun to be unraveled. One approach to understand the potential mechanism of gene regulation by caRNAs is to identify the caRNA-associated genomic regions. Several groups have developed methods to capture RNA-chromatin interactions in either one RNA vs the whole genome, i.e., "one-to-all" or all RNAs vs the whole genome, i.e., "all-to-all" manner. In this chapter, we discuss several state-of-the-art methods highlighting the principles behind them, the experimental procedures, the advantages and limitations, and their applications. Our goal is to provide an overview and guide to researchers interested in exploring caRNAs using these techniques.

circ-BPTF serves as a miR-486-5p sponge to regulate CEMIP and promotes hypoxic pulmonary arterial smooth muscle cell proliferation in COPD

Hypoxia plays a crucial role in pulmonary vascular remodelling at the early stage of chronic obstructive pulmonary disease (COPD). Circle RNA (circRNA) has been identified to play a critical role in multiple diseases. However, the role of circRNAs in pulmonary vascular remodelling in COPD remains unclear. In this study, we aim to investigate the role of circRNAs in pulmonary arterial smooth muscle cell proliferation and pulmonary vascular remodelling in COPD. COPD patients show lower partial pressure of arterial oxygen and pulmonary arterial remodeling as compared with controls. circRNA microarray and real-time PCR analyses show significantly higher level of circ-BPTF and lower miR-486-5p level in the pulmonary arteries of COPD patients as compared with controls. Hypoxia suppresses miR-486-5p expression but promotes expressions of circ-BPTF and cell migration inducing protein (CEMIP) in human pulmonary arterial smooth muscle cells (PASMCs) in vitro. Loss- and gain-of-function experiments show that circ-BPTF promotes PASMC proliferation in vitro. Moreover, luciferase reporter assay results indicate that circ-BPTF regulates PASMC proliferation by acting as an miR-486-5p sponge. CEMIP is identified as a candidate target gene of miR-486-5p by luciferase reporter assay. Overall, our study shows that circ-BPTF serves as a miR-486-5p sponge to regulate CEMIP and promote hypoxic PASMC proliferation in pulmonary vascular remodelling in COPD.

Calcium Signalling in Heart and Vessels: Role of Calmodulin and Downstream Calmodulin-Dependent Protein Kinases

Cardiovascular disease is the major cause of death worldwide. The success of medication and other preventive measures introduced in the last century have not yet halted the epidemic of cardiovascular disease. Although the molecular mechanisms of the pathophysiology of the heart and vessels have been extensively studied, the burden of ischemic cardiovascular conditions has risen to become a top cause of morbidity and mortality. Calcium has important functions in the cardiovascular system. Calcium is involved in the mechanism of excitation-contraction coupling that regulates numerous events, ranging from the production of action potentials to the contraction of cardiomyocytes and vascular smooth muscle cells. Both in the heart and vessels, the rise of intracellular calcium is sensed by calmodulin, a protein that regulates and activates downstream kinases involved in regulating calcium signalling. Among them is the calcium calmodulin kinase family, which is involved in the regulation of cardiac functions. In this review, we present the current literature regarding the role of calcium/calmodulin pathways in the heart and vessels with the aim to summarize our mechanistic understanding of this process and to open novel avenues for research.

CircHIPK3 Regulates Vascular Smooth Muscle Cell Calcification Via the miR-106a-5p/MFN2 Axis

Atherosclerosis is the most common arterial disease and is closely related to vascular calcification. CircHIPK3 has been implicated in atherosclerosis development, but the possible downstream regulatory mechanisms remain unclear. The levels of circHIPK3, miR-106a and MFN2 in tissues and blood samples of patients with atherosclerosis were detected by RT-qPCR. The levels of circHIPK3, miR-106a and MFN2 were detected by RT-qPCR and the expression levels of MFN2, osteogenic and cartilage differentiation marker proteins were detected by western blot in vitro. ALP staining, Alizarin Red staining, and calcium content detection evaluated the degree of osteogenic differentiation of cells. Alcian blue staining detected the level of cell cartilage differentiation. Luciferase detected the targeting relationship between circHIPK3 and miR-106a-5p, as well as miR-106a-5p and MFN2. CircHIPK3 and MFN2 were low expressed and miR-106a-5p was highly expressed in tissues and blood samples of patients with atherosclerosis, as well as vascular smooth muscle cell (VSMC) with osteogenic and cartilage differentiation. Overexpression of circHIPK3 reduced the cell mineralization and calcium content. Overexpression of circHIPK3 inhibited osteogenic differentiation by decreasing ALP activity, RUNX2, and OPG expression, and increasing SM22α and SMA level. What's more, overexpression of circHIPK3 decreased the chondrogenic differentiation by inhibiting the protein level of SOX9, aggrecan, and collagen II. CircHIPK3 targeted miR-106a-5p and miR-106a-5p targeted MFN2. MiR-106a-5p overexpression or MFN2 depletion repressed the effect of circHIPK3 overexpression on VSMC calcification. CircHIPK3 regulated osteogenic and cartilage differentiation of VSMC via miR-106a-5p/MFN2 axis, indicating a target for treating vascular calcification.

The role of circular RNAs in pulmonary hypertension

Circular RNAs (circRNAs) are endogenous, covalently circularised, non-protein-coding RNAs generated from back-splicing. Most circRNAs are very stable, highly conserved, and expressed in a tissue-, cell- and developmental stage-specific manner. circRNAs play a significant role in various biological processes, such as regulation of gene expression and protein translation via sponging of microRNAs and binding with RNA-binding proteins. circRNAs have become a topic of great interest in research due to their close link with the development of various diseases. Their high stability, conservation and abundance in body fluids make them promising biomarkers for many diseases. A growing body of evidence suggests that aberrant expression of circRNAs and their targets plays a crucial role in pulmonary vascular remodelling and pulmonary arterial hypertension (group 1) as well as other forms (groups 3 and 4) of pulmonary hypertension (PH). Here we discuss the roles and molecular mechanisms of circRNAs in the pathogenesis of pulmonary vascular remodelling and PH. We also highlight the therapeutic and biomarker potential of circRNAs in PH.

CircGSAP alleviates pulmonary microvascular endothelial cells dysfunction in pulmonary hypertension via regulating miR-27a-3p/BMPR2 axis

Background

Our previous study showed that circular RNA-gamma-secretase-activating protein (circGSAP) was down-regulated in pulmonary microvascular endothelial cells (PMECs) in response to hypoxia, and regulated the cell cycle of PMECs via miR-942-5p sponge in pulmonary hypertension (PH). However, the mechanism whether circGSAP affects the dysfunction of PEMCs through other microRNAs (miRNAs) remains largely unknown. Therefore, we aimed to demonstrate the underlying mechanisms of circGSAP regulating PMECs dysfunction by absorbing other miRNAs to regulate target genes in idiopathic pulmonary arterial hypertension (IPAH).

Methods

Quantitative real-time polymerase chain reaction, immunofluorescence staining, Cell Counting Kit-8, Calcein-AM/PI staining, Transwell assay, dual-luciferase reporter assay, and ELISA were used to elucidate the roles of circGSAP.

Results

Here we showed that plasma circGSAP levels were significantly decreased in patients with IPAH and associated with poor outcomes. In vivo, circGSAP overexpression improved survival, and alleviated pulmonary vascular remodeling of monocrotaline-induced PH (MCT-PH) rats. In vitro, circGSAP overexpression inhibited hypoxia-induced PMECs proliferation, migration and increased mortality by absorbing miR-27a-3p. BMPR2 was identified as a miR-27a-3p target gene. BMPR2 silencing ameliorated the effect of the miR-27a-3p inhibitor on PMECs proliferation,migration and mortality. The levels of BMPR2 were upregulated in circGSAP-overexpressed PMECs and lung tissues of MCT-PH rats.

Conclusion

Our findings demonstrated that circGSAP alleviated the dysfunction of PMECs via the increase of BMPR2 by competitively binding with miR-27a-3p, and mitigated pulmonary vascular remodeling of MCT-PH rats, providing potential therapeutic strategies for IPAH.

Circular RNAs Regulate Vascular Remodelling in Pulmonary Hypertension

Circular RNAs (circRNAs) are a newly identified type of noncoding RNA molecule with a unique closed-loop structure. circRNAs are widely expressed in different tissues and developmental stages of many species, participating in many important pathophysiological processes and playing an important role in the occurrence and development of diseases. This article reviews the discovery, characteristics, formation, and biological function of circRNAs. The relationship between circRNAs and vascular remodelling, as well as the current status of research and potential application value in pulmonary hypertension (PH), is discussed to promote a better understanding of the role of circRNAs in PH. circRNAs are closely related to the remodelling of vascular endothelial cells and vascular smooth muscle cells. circRNAs have potential application prospects for in-depth research on the possible pathogenesis and mechanism of PH. Future research on the role of circRNAs in the pathogenesis and mechanism of PH will provide new insights and promote screening, diagnosis, prevention, and treatment of this disease.

Pulmonary hypertension: Linking inflammation and pulmonary arterial stiffening

Pulmonary hypertension (PH) is a progressive disease that arises from multiple etiologies and ultimately leads to right heart failure as the predominant cause of morbidity and mortality. In patients, distinct inflammatory responses are a prominent feature in different types of PH, and various immunomodulatory interventions have been shown to modulate disease development and progression in animal models. Specifically, PH-associated inflammation comprises infiltration of both innate and adaptive immune cells into the vascular wall of the pulmonary vasculature—specifically in pulmonary vascular lesions—as well as increased levels of cytokines and chemokines in circulating blood and in the perivascular tissue of pulmonary arteries (PAs). Previous studies suggest that altered hemodynamic forces cause lung endothelial dysfunction and, in turn, adherence of immune cells and release of inflammatory mediators, while the resulting perivascular inflammation, in turn, promotes vascular remodeling and the progression of PH. As such, a vicious cycle of endothelial activation, inflammation, and vascular remodeling may develop and drive the disease process. PA stiffening constitutes an emerging research area in PH, with relevance in PH diagnostics, prognostics, and as a therapeutic target. With respect to its prognostic value, PA stiffness rivals the well-established measurement of pulmonary vascular resistance as a predictor of disease outcome. Vascular remodeling of the arterial extracellular matrix (ECM) as well as vascular calcification, smooth muscle cell stiffening, vascular wall thickening, and tissue fibrosis contribute to PA stiffening. While associations between inflammation and vascular stiffening are well-established in systemic vascular diseases such as atherosclerosis or the vascular manifestations of systemic sclerosis, a similar connection between inflammatory processes and PA stiffening has so far not been addressed in the context of PH. In this review, we discuss potential links between inflammation and PA stiffening with a specific focus on vascular calcification and ECM remodeling in PH.

CircGSAP regulates the cell cycle of pulmonary microvascular endothelial cells via the miR-942-5p sponge in pulmonary hypertension

Background We recently demonstrated that circGSAP was diminished in lung tissues from patients with pulmonary arterial hypertension and in hypoxia-induced pulmonary microvascular endothelial cells (PMECs). However, the underlying role of circGSAP in PMECs remains unknown. The study aimed to investigate the contribution of circGSAP to proliferation, apoptosis and cell cycle of PMECs in hypoxic environment and explore the mechanism.

Methods The expression of circGSAP was quantified by real-time PCR or immunofluorescence in human lung tissue and PMECs. CircGSAP plasmid, circGSAP small interfering RNA (siRNA), miRNA inhibitor and target gene siRNA were synthesized to verify the role of circGSAP on regulating the proliferation, apoptosis, and cell cycle of PMECs.

Results CircGSAP levels were decreased in lungs and plasma of patients with pulmonary hypertension second to chronic obstructive pulmonary disease (COPD-PH) and were associated with poor outcomes of COPD-PH patients. Upregulation of circGSAP inhibited proliferation, apoptosis resistance and G1/S transition of PMECs. Dual luciferase reporter assays showed that circGSAP acted as a competitive endogenous RNA regulating miR-942-5p, and identified SMAD4 as a target gene of miR-942-5p, Then, we verified the functions of miR-942-5p and SMAD4 in PMECs. In addition, the effect of circGSAP siRNA on PMECs was mitigated by transfection of miR-942-5p inhibitor, and the effect of miR-942-5p inhibitor on PMECs was inhibited by SMAD4 siRNA.

Conclusion Our findings demonstrated that diminished circGSAP accelerated cell cycle to facilitate cell proliferation and apoptosis resistance through competitively binding miR-942-5p to modulate SMAD4 expressions in hypoxia-induced PMECs, indicating potential therapeutic strategies for PH.

Silencing CAMK2D Promotes the Proliferation of Spermatogonia in the Testis of Experimental Varicocele Rats

Varicocele is regarded as the main factor that contributes to male infertility. This study aimed to explore the effect of CAMK2D on spermatogonia in the testis of experimental varicocele rats. The experimental varicocele model was established in rats and treated using different ligation methods. mRNA expression profile analysis was performed on the left testicular tissue isolated from different groups, and differentially expressed genes (DEGs) were analysed by bioinformatics methods and identified by qRT-PCR. The effect of CAMK2D, the screened DEG, on the proliferation of spermatogonia was evaluated by CCK-8 assay. The expression level of the c-kit was measured by the immunofluorescence assay and the expression levels of CAMKII, FOXO1, and β-catenin were detected by qRT-PCR and western blotting. Five DEGs (i.e., TMCC3, FLNB, CAMK2D, OPLAH, and EGR1) were screened using the comprehensive analysis of mRNA high-throughput sequencing data. TMCC3 and FLNB were significantly downregulated, and CAMK2D, OPLAH, and EGR1 were dramatically upregulated in the testicular tissue of varicocele rats. The target DEG CAMK2D was obtained through identification by using qRT-PCR. In vitro assays revealed that the proliferation of spermatogonia was significantly facilitated by the silencing of CAMK2D, which resulted in the downregulation of CAMKII, FOXO1, and β-catenin. In conclusion, silencing CAMK2D facilitated the proliferation of spermatogonia in the testis of experimental varicocele rats.

Epigenetic regulation in cardiovascular disease: mechanisms and advances in clinical trials

Epigenetics is closely related to cardiovascular diseases. Genome-wide linkage and association analyses and candidate gene approaches illustrate the multigenic complexity of cardiovascular disease. Several epigenetic mechanisms, such as DNA methylation, histone modification, and noncoding RNA, which are of importance for cardiovascular disease development and regression. Targeting epigenetic key enzymes, especially the DNA methyltransferases, histone methyltransferases, histone acetylases, histone deacetylases and their regulated target genes, could represent an attractive new route for the diagnosis and treatment of cardiovascular diseases. Herein, we summarize the knowledge on epigenetic history and essential regulatory mechanisms in cardiovascular diseases. Furthermore, we discuss the preclinical studies and drugs that are targeted these epigenetic key enzymes for cardiovascular diseases therapy. Finally, we conclude the clinical trials that are going to target some of these processes.

The Landscape of Noncoding RNA in Pulmonary Hypertension

The transcriptome of pulmonary hypertension (PH) is complex and highly genetically heterogeneous, with noncoding RNA transcripts playing crucial roles. The majority of RNAs in the noncoding transcriptome are long noncoding RNAs (lncRNAs) with less circular RNAs (circRNAs), which are two characteristics gaining increasing attention in the forefront of RNA research field. These noncoding transcripts (especially lncRNAs and circRNAs) exert important regulatory functions in PH and emerge as potential disease biomarkers and therapeutic targets. Recent technological advancements have established great momentum for discovery and functional characterization of ncRNAs, which include broad transcriptome sequencing such as bulk RNA-sequence, single-cell and spatial transcriptomics, and RNA-protein/RNA interactions. In this review, we summarize the current research on the classification, biogenesis, and the biological functions and molecular mechanisms of these noncoding RNAs (ncRNAs) involved in the pulmonary vascular remodeling in PH. Furthermore, we highlight the utility and challenges of using these ncRNAs as biomarkers and therapeutics in PH.

Bioinformatic analysis of dysregulated circular RNAs in pediatric pulmonary hypertension linked congenital heart disease

BACKGROUND

Circular RNAs (circRNAs) may play important roles in the progression of pulmonary arterial hypertension. However, the potential roles they play in childhood pulmonary arterial hypertension associated congenital heart disease (CHD) progression remains unclear.

METHODS

Thirteen human plasma samples including eight from pulmonary arterial hypertension secondary to CHD patients and five from a control group were analyzed using the Arraystar Human circRNA array. The relative expression levels of five differentially expressed circRNAs in pulmonary arterial hypertension were detected using real-time polymerase chain reaction (PCR) analysis. In parallel, these levels were also taken on control samples from 32 CHD patients. We used miRanda and TargetScan software packages to predict potential microRNA (miRNA)targets, which were then combined into a circRNA-miRNA-messenger RNA (mRNA) network.

RESULTS

Twenty-seven circRNAs (three upregulated and 24 downregulated) were differentially expressed between the pulmonary arterial hypertension and control groups. Compared to control group levels, circ_003416 expression in the pulmonary arterial hypertension group was significantly downregulated, while circ_005372 expression, in contrast, was significantly upregulated. The differential expression of these circRNAs was mainly linked to variation in levels of oxidative phosphorylation and tight junction signaling.

CONCLUSIONS

We identified one overexpressed and one underexpressed circRNA in plasma samples from children with CHD associated pulmonary arterial hypertension. Bioinformatic analysis indicated these dysregulated circRNAs might be associated with the occurrence and regulation of pulmonary arterial hypertension.

Decoding ceRNA regulatory network in the pulmonary artery of hypoxia-induced pulmonary hypertension (HPH) rat model

Background

Hypoxia-induced pulmonary hypertension (HPH) is a lethal cardiovascular disease with the characteristic of severe remodeling of pulmonary vascular. Although a large number of dysregulated mRNAs, lncRNAs, circRNAs, and miRNAs related to HPH have been identified from extensive studies, the competitive endogenous RNA (ceRNA) regulatory network in the pulmonary artery that responds to hypoxia remains largely unknown.

Results

Transcriptomic profiles in the pulmonary arteries of HPH rats were characterized through high-throughput RNA sequencing in this study. Through relatively strict screening, a set of differentially expressed RNAs (DERNAs) including 19 DEmRNAs, 8 DElncRNAs, 19 DEcircRNAs, and 23 DEmiRNAs were identified between HPH and normal rats. The DEmRNAs were further found to be involved in cell adhesion, axon guidance, PPAR signaling pathway, and calcium signaling pathway, suggesting their crucial role in HPH. Moreover, a hypoxia-induced ceRNA regulatory network in the pulmonary arteries of HPH rats was constructed according to the ceRNA hypothesis. More specifically, the ceRNA network was composed of 10 miRNAs as hub nodes, which might be sponged by 6 circRNAs and 7 lncRNAs, and directed the expression of 18 downstream target genes that might play important role in the progression of HPH. The expression patterns of selected DERNAs in the ceRNA network were then validated to be consistent with sequencing results in another three independent batches of HPH and normal control rats. The diagnostic effectiveness of several hub mRNAs in ceRNA network was further evaluated through investigating their expression profiles in patients with pulmonary artery hypertension (PAH) recorded in the Gene Expression Omnibus (GEO) dataset GSE117261. Dysregulated POSTN, LTBP2, SPP1, and LSAMP were observed in both the pulmonary arteries of HPH rats and lung tissues of PAH patients.

Conclusions

A ceRNA regulatory network in the pulmonary arteries of HPH rats was constructed, 10 hub miRNAs and their corresponding interacting lncRNAs, circRNAs, and mRNAs were identified. The expression patterns of selected DERNAs were further validated to be consistent with the sequencing result. POSTN, LTBP2, SPP1, and LSAMP were suggested to be potential diagnostic biomarkers and therapeutic targets for PAH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00762-1.

hsa_circWDR37_016 Regulates Hypoxia-Induced Proliferation of Pulmonary Arterial Smooth Muscle Cells

Pulmonary arterial hypertension (PAH) is characterized by abnormal remodeling of pulmonary vessel walls caused by excessive pulmonary arterial smooth muscle cell (PASMC) proliferation. Our previous clinical studies have demonstrated the importance of the downregulated circRNA in PAH. However, the role of upregulated circRNAs is still elusive. Here, we identified the upregulated circRNA in PAH patients, hsa_circWDR37_016 (circWDR37), as a key regulator of hypoxic proliferative disorder of pulmonary arterial smooth muscle cells (PASMCs). Quantitative real-time PCR (qRT-PCR) analysis validated that exposure to hypoxia markedly increased the circWDR37 level in cultured human PASMCs. As evidenced by flow cytometry, 5-ethynyl-2′-deoxyuridine (EdU) incorporation, wound healing, and Tunel assay, silencing of endogenous circWDR37 attenuated proliferation and cell-cycle progression in hypoxia-exposed human PASMCs in vitro. Furthermore, bioinformatics and Luciferase assay showed that circWDR37 directly sponged hsa-miR-138-5p (miR-138) and was involved in the immunoregulatory and inflammatory processes of PAH. Together, these studies suggested new insights into circRNA regulated the pathology of PAH, providing a new potential therapeutic target for PAH treatment.

Integrative Studies of Human Cord Blood Derived Mononuclear Cells and Umbilical Cord Derived Mesenchyme Stem Cells in Ameliorating Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a common pulmonary complication observed in preterm infants that is composed of multifactorial pathogenesis. Current strategies, albeit successful in moderately reducing morbidity and mortality of BPD, failed to draw overall satisfactory conclusion. Here, using a typical mouse model mimicking hallmarks of BPD, we revealed that both cord blood-derived mononuclear cells (CB-MNCs) and umbilical cord-derived mesenchymal stem cells (UC-MSCs) are efficient in alleviating BPD. Notably, infusion of CB-MNCs has more prominent effects in preventing alveolar simplification and pulmonary vessel loss, restoring pulmonary respiratory functions and balancing inflammatory responses. To further elucidate the underlying mechanisms within the divergent therapeutic effects of UC-MSC and CB-MNC, we systematically investigated the long noncoding RNA (lncRNA)-microRNA (miRNA)-messenger RNA (mRNA) and circular RNA (circRNA)-miRNA-mRNA networks by whole-transcriptome sequencing. Importantly, pathway analysis integrating Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG)/gene set enrichment analysis (GSEA) method indicates that the competing endogenous RNA (ceRNA) network is mainly related to the regulation of GTPase activity (GO: 0043087), extracellular signal-regulated kinase 1 (ERK1) and ERK2 signal cascade (GO: 0070371), chromosome regulation (GO: 0007059), and cell cycle control (GO: 0044770). Through rigorous selection of the lncRNA/circRNA-based ceRNA network, we demonstrated that the hub genes reside in UC-MSC- and CB-MNC-infused networks directed to the function of cell adhesion, motor transportation (Cdk13, Lrrn2), immune homeostasis balance, and autophagy (Homer3, Prkcd) relatively. Our studies illustrate the first comprehensive mRNA-miRNA-lncRNA and mRNA-miRNA-circRNA networks in stem cell-infused BPD model, which will be valuable in identifying reliable biomarkers or therapeutic targets for BPD pathogenesis and shed new light in the priming and conditioning of UC-MSCs or CB-MNCs in the treatment of neonatal lung injury.

Integrated analysis of lncRNA-miRNA-mRNA ceRNA network in human aortic dissection

Background

Many studies on long chain non-coding RNAs (lncRNAs) are published in recent years. But the roles of lncRNAs in aortic dissection (AD) are still unclear and should be further examined. The present work focused on determining the molecular mechanisms underlying lncRNAs regulation in aortic dissection on the basis of the lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network.

Methods

This study collected the lncRNAs (GSE52093), mRNAs (GSE52093) and miRNAs (GSE92427) expression data within human tissue samples with aortic dissection group and normal group based on Gene Expression Omnibus (GEO) database.

Results

This study identified three differentially expressed lncRNAs (DELs), 19 differentially expressed miRNAs (DEmiRs) and 1046 differentially expressed mRNAs (DEGs) identified regarding aortic dissection. Furthermore, we constructed a lncRNA-miRNA-mRNA network through three lncRNAs (including two with up-regulation and one with down-regulation), five miRNAs (five with up-regulation), as well as 211 mRNAs (including 103 with up-regulation and 108 with down-regulation). Simultaneously, we conducted functional enrichment and pathway analyses on genes within the as-constructed ceRNA network. According to our PPI/ceRNA network and functional enrichment analysis results, four critical genes were found (E2F2, IGF1R, BDNF and PPP2R1B). In addition, E2F2 level was possibly modulated via lncRNA FAM87A-hsa-miR-31-5p/hsa-miR-7-5p or lncRNA C9orf106-hsa-miR-7-5p. The expression of IGF1R may be regulated by lncRNA FAM87A-hsa-miR-16-5p/hsa-miR-7-5p or lncRNA C9orf106-hsa-miR-7-5p.

Conclusion

In conclusion, the ceRNA interaction axis we identified is a potentially critical target for treating AD. Our results shed more lights on the possible pathogenic mechanism in AD using a lncRNA-associated ceRNA network.

Knockdown of CNN3 Impairs Myoblast Proliferation, Differentiation, and Protein Synthesis via the mTOR Pathway

Background

Myogenesis is a complex process that requires optimal outside–in substrate–cell signaling. Calponin 3 (CNN3) plays an important role in regulating myogenic differentiation and muscle regeneration; however, the precise function of CNN3 in myogenesis regulation remains poorly understood. Here, we investigated the role of CNN3 in a knockdown model in the mouse muscle cell line C2C12.

Methods

Myoblast proliferation, migration, differentiation, fusion, and protein synthesis were examined in CNN3 knockdown C2C12 mouse muscle cells. Involvement of the mTOR pathway in CNN3 signaling was explored by treating cells with the mTOR activator MHY1485. The regulatory mechanisms of CNN3 in myogenesis were further examined by RNA sequencing and subsequent gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene set enrichment analysis (GSEA).

Results

During proliferation, CNN3 knockdown caused a decrease in cell proliferation and migration. During differentiation, CNN3 knockdown inhibited myogenic differentiation, fusion, and protein synthesis in C2C12 cells via the AKT/mTOR and AMPK/mTOR pathways; this effect was reversed by MHY1485 treatment. Finally, KEGG and GSEA indicated that the NOD-like receptor signaling pathway is affected in CNN3 knockdown cell lines.

Conclusion

CNN3 may promote C2C12 cell growth by regulating AKT/mTOR and AMPK/mTOR signaling. The KEGG and GSEA indicated that inhibiting CNN3 may activate several pathways, including the NOD-like receptor pathway and pathways involved in necroptosis, apoptosis, and inflammation.

MicroRNA-135b/CAMK2D Axis Contribute to Malignant Progression of Gastric Cancer through EMT Process Remodeling

There is a continued need for investigating the roles of microRNAs (miRNAs) and their targets on the progression of gastric cancer (GC), especially metastasis. Here, we performed an integrated study to identify dysregulated miRNAs critical for GC development and progression. miR-135b was determined as a promising biomarker for GC. The expression level of miR-135b was increased among GC cell lines, patient tumor tissues, serum samples, and correlation with aggravation of the GC patients. The in vitro functional assays demonstrated overexpression of miR-135b promoted cell proliferation, migration and invasion in GC, while miR-135b inhibition led to the opposite results. CAMK2D was found to be the direct target of miR-135b, serving as a tumor suppressor in GC cells. Based on our and public datasets, we confirmed the attenuation of CAMK2D expression in GC tissues. And, the expression levels of miR-135b and CAMK2D were closely associated with prognosis of GC patients. Ectopic expression of miR-135b resulted in the down-regulation of CAMK2D. Additionally, CAMK2D was a prerequisite for miR-135b to promote GC cells proliferation and migration by regulating the EMT process, which was confirmed by the in vivo experiments. Importantly, in vivo injection of miR-135b antagomir significantly repressed the tumor growth and metastasis of xenograft models, which suggested that the miR-135b antagomir were promising for clinical applications. Taken together, these results indicate that miR-135b/CAMK2D axis drives GC progression by EMT process remodeling, suggesting that miR-135b may be utilized as a new therapeutic target and prognostic marker for GC patients.

MiR-7 in Cancer Development

MicroRNAs (miRNAs) are short non-coding RNA involved in the regulation of specific mRNA translation. They participate in cellular signaling circuits and can act as oncogenes in tumor development, so-called oncomirs, as well as tumor suppressors. miR-7 is an ancient miRNA involved in the fine-tuning of several signaling pathways, acting mainly as tumor suppressor. Through downregulation of PI3K and MAPK pathways, its dominant role is the suppression of proliferation and survival, stimulation of apoptosis and inhibition of migration. Besides these functions, it has numerous additional roles in the differentiation process of different cell types, protection from stress and chromatin remodulation. One of the most investigated tissues is the brain, where its downregulation is linked with glioblastoma cell proliferation. Its deregulation is found also in other tumor types, such as in liver, lung and pancreas. In some types of lung and oral carcinoma, it can act as oncomir. miR-7 roles in cell fate determination and maintenance of cell homeostasis are still to be discovered, as well as the possibilities of its use as a specific biotherapeutic.

Matrix stiffening induces a pathogenic QKI-miR-7-SRSF1 signaling axis in pulmonary arterial endothelial cells

Pulmonary arterial hypertension (PAH) refers to a set of heterogeneous vascular diseases defined by elevation of pulmonary arterial pressure (PAP) and pulmonary vascular resistance (PVR), leading to right ventricular (RV) remodeling and often death. Early increases in pulmonary artery stiffness in PAH drive pathogenic alterations of pulmonary arterial endothelial cells (PAECs), leading to vascular remodeling. Dysregulation of microRNAs can drive PAEC dysfunction. However, the role of vascular stiffness in regulating pathogenic microRNAs in PAH is incompletely understood. Here, we demonstrated that extracellular matrix (ECM) stiffening downregulated miR-7 levels in PAECs. The RNA-binding protein quaking (QKI) has been implicated in the biogenesis of miR-7. Correspondingly, we found that ECM stiffness upregulated QKI, and QKI knockdown led to increased miR-7. Downstream of the QKI-miR-7 axis, the serine and arginine-rich splicing factor 1 (SRSF1) was identified as a direct target of miR-7. Correspondingly, SRSF1 was reciprocally upregulated in PAECs exposed to stiff ECM and was negatively correlated with miR-7. Decreased miR-7 and increased QKI and SRSF1 were observed in lungs from patients with PAH and PAH rats exposed to SU5416/hypoxia. Lastly, miR-7 upregulation inhibited human PAEC migration, whereas forced SRSF1 expression reversed this phenotype, proving that miR-7 depended upon SRSF1 to control migration. In aggregate, these results define the QKI-miR-7-SRSF1 axis as a mechanosensitive mechanism linking pulmonary arterial vascular stiffness to pathogenic endothelial function. These findings emphasize implications relevant to PAH and suggest the potential benefit of developing therapies that target this miRNA-dependent axis in PAH.