Diagnostic and Therapeutic Value of Hsa_circ_0002594 for T Helper 2-Mediated Allergic Asthma

Unveiling the hidden power of noncoding RNAs in pediatric respiratory diseases

Respiratory diseases in children are common health problems that significantly impact their quality of life and health status, and this has its own unique challenges compared to adults. A growing body of research has focused on epigenetic mechanisms that relate with the development of various diseases, such as pediatric respiratory diseases. Noncoding RNAs (ncRNAs), especially long noncoding RNAs, microRNA, and circular RNA, are reported to play a regulatory role in pediatric respiratory diseases whose mutations or aberrant expressions are strongly associated with the development of these diseases. In this review, we mainly discussed the functions of these three ncRNAs in pediatric respiratory diseases.

Circular RNAs in human diseases

Circular RNAs (circRNAs) are a unique class of RNA molecules formed through back-splicing rather than linear splicing. As an emerging field in molecular biology, circRNAs have garnered significant attention due to their distinct structure and potential functional implications. A comprehensive understanding of circRNAs' functions and potential clinical applications remains elusive despite accumulating evidence of their involvement in disease pathogenesis. Recent research highlights their significant roles in various human diseases, but comprehensive reviews on their functions and applications remain scarce. This review provides an in-depth examination of circRNAs, focusing first on their involvement in non-neoplastic diseases such as respiratory, endocrine, metabolic, musculoskeletal, cardiovascular, and renal disorders. We then explore their roles in tumors, with particular emphasis on exosomal circular RNAs, which are crucial for cancer initiation, progression, and resistance to treatment. By detailing their biogenesis, functions, and impact on disease mechanisms, this review underscores the potential of circRNAs as diagnostic biomarkers and therapeutic targets. The review not only enhances our understanding of circRNAs' roles in specific diseases and tumor types but also highlights their potential as novel diagnostic and therapeutic tools, thereby paving the way for future clinical investigations and potential therapeutic interventions.

CircRNA: a rising therapeutic strategy for lung injury induced by pulmonary toxicants

Lung injury has been a serious medical problem that requires new therapeutic approaches and biomarkers. Circular RNAs (circRNAs) are non-coding RNAs (ncRNAs) that exist widely in eukaryotes. CircRNAs are single-stranded RNAs that form covalently closed loops. CircRNAs are significant gene regulators that have a role in the development, progression, and therapy of lung injury by controlling transcription, translating into protein, and sponging microRNAs (miRNAs) and proteins. Although the study of circRNAs in lung injury caused by pulmonary toxicants is just beginning, several studies have revealed their expression patterns. The function that circRNAs perform in relation to pulmonary toxicants (severe acute respiratory distress syndrome coronavirus-2 (SARS-CoV-2), drug abuse, PM2.5, and cigarette smoke) is the main topic of this review. A variety of circRNAs can serve as potential biomarkers of lung injury. In this review, the biogenesis, properties, and biological functions of circRNAs were concluded, and the relationship between circRNAs and pulmonary toxicants was discussed. It is expected that the new ideas and potential treatment targets that circRNAs provide would be beneficial to research into the molecular mechanisms behind lung injury.

Unwinding circular RNA's role in inflammatory pulmonary diseases

Circular RNAs (circRNAs) have emerged as pivotal regulators of gene expression and cellular processes in various physiological and pathological conditions. In recent years, there has been a growing interest in investigating the role of circRNAs in inflammatory lung diseases, owing to their potential to modulate inflammation-associated pathways and contribute to disease pathogenesis. Inflammatory lung diseases, like asthma, chronic obstructive pulmonary disease (COPD), and COVID-19, pose significant global health challenges. The dysregulation of inflammatory responses demonstrates a pivotal function in advancing these diseases. CircRNAs have been identified as important players in regulating inflammation by functioning as miRNA sponges, engaging with RNA-binding proteins, and participating in intricate ceRNA networks. These interactions enable circRNAs to regulate the manifestation of key inflammatory genes and signaling pathways. Furthermore, emerging evidence suggests that specific circRNAs are differentially expressed in response to inflammatory stimuli and exhibit distinct patterns in various lung diseases. Their involvement in immune cell activation, cytokine production, and tissue remodeling processes underscores their possible capabilities as therapeutic targets and diagnostic biomarkers. Harnessing the knowledge of circRNA-mediated regulation in inflammatory lung diseases could lead to the development of innovative strategies for disease management and intervention. This review summarizes the current understanding of the role of circRNAs in inflammatory lung diseases, focusing on their regulatory mechanisms and functional implications.

Regulatory and therapeutic implications of competing endogenous RNA network in breast cancer progression and metastasis: A review

Breast cancer (BC) is a global health concern, and development of diagnostic tools and targeted treatments for BC remains challenging. Therapeutic approaches for BC often involve a combination of surgery, radiation therapy, chemotherapy, targeted therapy, and hormone therapy. In recent years, there has been a growing interest in the role of noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs) and microRNAs (miRNAs), in BC and their therapeutic implications. Various biological processes such as cell proliferation, migration, and apoptosis rely on the activities of these ncRNAs, and their dysregulation has been implicated in BC progression. The regulatory function of the competitive endogenous RNA (ceRNA) network, which comprises lncRNAs, miRNAs, and mRNAs, has been the subject of extensive pathophysiological research. Most lncRNAs serve as molecular sponges for miRNAs and sequester their activities, thereby regulating the expression of target mRNAs and contributing to the promotion or inhibition of BC progression. This review summarizes recent findings on the role of ceRNA networks in BC progression, metastasis, and therapeutic resistance, and highlights the association of ceRNA networks with transcription factors and signaling pathways. Understanding the ceRNA network can lead to the discovery of biomarkers and targeted treatment methods to prevent the spread and metastasis of BC.

A novel piwi-interacting RNA associates with type 2-high asthma phenotypes

BACKGROUND

Piwi-interacting RNAs (piRNAs), comprising the largest noncoding RNA group, regulate transcriptional processes. Whether piRNAs are associated with type 2 (T2)-high asthma is unknown.

OBJECTIVE

We sought to investigate the association between piRNAs and T2-high asthma in childhood asthma.

METHODS

We sequenced plasma samples from 462 subjects in the Childhood Asthma Management Program (CAMP) as the discovery cohort and 1165 subjects in the Genetics of Asthma in Costa Rica Study (GACRS) as a replication cohort. Sequencing reads were filtered first, and piRNA reads were annotated and normalized. Linear regression was used for the association analysis of piRNAs and peripheral blood eosinophil count, total serum IgE level, and long-term asthma exacerbation in children with asthma. Mediation analysis was performed to investigate the effect direction. We then ascertained if the circulating piRNAs were present in asthmatic airway epithelial cells in a Gene Expression Omnibus (GEO; www.ncbi.nlm.nih.gov/geo) public data set.

RESULTS

Fifteen piRNAs were significantly associated with eosinophil count in CAMP (P ≤ .05), and 3 were successfully replicated in GACRS. Eleven piRNAs were associated with total IgE in CAMP, and one of these was replicated in GACRS. All 22 significant piRNAs were identified in epithelial cells in vitro, and 6 of these were differentially expressed between subjects with asthma and healthy controls. Fourteen piRNAs were associated with long-term asthma exacerbation, and effect of piRNAs on long-term asthma exacerbation are mediated through eosinophil count and serum IgE level.

CONCLUSION

piRNAs are associated with peripheral blood eosinophils and total serum IgE in childhood asthma and may play important roles in T2-high asthma.

Circular RNAs: emerging players in asthma and COPD

Circular RNAs (circRNAs) belong to a unique class of endogenously expressed non-protein-coding RNAs with a distinct circularized structure, characterized by the absence of 5'-cap and 3'-polyadenylate ends. They are generally formed through back-splicing from pre-mRNAs. They serve as regulators of transcription and splicing, and act as sponges for microRNAs (miRNAs) and RNA-binding proteins, thereby modulating the expression of target genes. As a result, they exert a substantial impact on a diverse array of cellular and biological processes, including cell proliferation, migration, inflammation, and oxidative stress. Asthma and COPD are chronic airway conditions that currently have no cure. In recent years, emerging evidence suggests that altered expression of circRNAs in airway, bronchial and immune cells is involved in asthma and COPD pathogenesis. Studies exploring circRNA dysregulation in asthma have showcased their involvement in regulating the proliferation, migration, and inflammation of airway smooth muscle and bronchial epithelial cells, as well as impacting goblet cell metaplasia, Th2 cell differentiation, and macrophage activation, primarily through interactions with miRNAs. Similarly, in COPD, circRNAs have shown altered expression patterns in the blood and lungs of patients, and these changes have been linked to modulating inflammation, oxidative stress, and airway remodeling in preclinical models. Furthermore, certain circRNAs have demonstrated promising potential as diagnostic and prognostic biomarkers for both asthma and COPD. This review delves into the current understanding of the function and molecular mechanisms of circRNAs in asthma and COPD, along with exploring their potential as biomarkers in these respiratory conditions.

The Role of Noncoding RNA in Airway Allergic Diseases through Regulation of T Cell Subsets

Allergic rhinitis and asthma are common airway allergic diseases, the incidence of which has increased annually in recent years. The human body is frequently exposed to allergens and environmental irritants that trigger immune and inflammatory responses, resulting in altered gene expression. Mounting evidence suggested that epigenetic alterations were strongly associated with the progression and severity of allergic diseases. Noncoding RNAs (ncRNAs) are a class of transcribed RNA molecules that cannot be translated into polypeptides and consist of three major categories, microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs). Previous studies showed that ncRNAs were involved in the physiopathological mechanisms of airway allergic diseases and contributed to their occurrence and development. This article reviews the current state of understanding of the role of noncoding RNAs in airway allergic diseases, highlights the limitations of recent studies, and outlines the prospects for further research to facilitate the clinical translation of noncoding RNAs as therapeutic targets and biomarkers.

Construction of Severe Eosinophilic Asthma Related Competing Endogenous RNA Network by Weighted Gene Co-Expression Network Analysis

Background: Currently, disease control in patients with severe eosinophilic asthma is not optimistic. Competing endogenous RNA (ceRNA) networks have been found to play a key role in asthma in recent years. However, it is unclear whether ceRNA networks play an important part in severe eosinophilic asthma. Methods: Firstly, gene expression profiles related to severe eosinophilic asthma were downloaded from the Gene Expression Omnibus (GEO) database. Secondly, the key modules were identified by the weighted gene co-expression network analysis (WGCNA). Thirdly, genes in modules highly associated with severe eosinophilic asthma were selected for further construction of the ceRNA network. Fourthly, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on hub genes. Finally, the results of this study were validated on the GSE143303, GSE137268, and GSE147878 datasets. Results: 22 severe eosinophilic asthmatics and 13 healthy controls were extracted for WGCNA. We found that the genes in the black module (r = -0.75, p < 0.05) and yellow module (r = 0.65, p < 0.05) were highly associated with severe eosinophilic asthma. EP300 was discovered to serve the key connecting function in the ceRNA network. Surprisingly, lncRNAs seem to eliminate the role of EP300 in the black module and we discovered that CCT8 and miRNA-mRNA formed a circRNA-miRNA-mRNA network in the yellow module. We found that EP300 and FOXO3 in the black module were regulated by steroid hormones in the enrichment analysis, which were related to the medication used by the patient. Through validation of other datasets, we found that the hub genes in the yellow module were the key genes in the treatment of severe eosinophilic asthma. In particular, RPL17 and HNRNPK might specifically regulate severe eosinophilic asthma. Conclusion: RPL17 and HNRNPK might particularly regulate severe eosinophilic asthma. Our results could be useful to provide potential immunotherapy targets and prognostic markers for severe eosinophilic asthma.

Past, Present and Future: The Relationship Between Circular RNA and Immunity

The immune system has evolved since the birth of humans. However, immune-related diseases have not yet been overcome due to the lack of expected indicators and targeting specificity of current medical technology, subjecting patients to very uncomfortable physical and mental experiences and high medical costs. Therefore, the requirements for treatments with higher specificity and indicative ability are raised. Fortunately, the discovery of and continuous research investigating circular RNAs (circRNAs) represent a promising method among numerous methods. Although circRNAs wear regarded as metabolic wastes when discovered, as a type of noncoding RNA (ncRNA) with a ring structure and wide distribution range in the human body, circRNAs shine brilliantly in medical research by virtue of their special nature and structure-determined functions, such as high stability, wide distribution, high detection sensitivity, acceptable reproducibility and individual differences. Based on research investigating the role of circRNAs in immunity, we systematically discuss the hotspots of the roles of circRNAs in immune-related diseases, including expression profile analyses, potential biomarker research, ncRNA axis/network construction, impacts on phenotypes, therapeutic target seeking, maintenance of nucleic acid stability and protein binding research. In addition, we summarize the current situation of and problems associated with circRNAs in immune research, highlight the applications and prospects of circRNAs in the treatment of immune-related diseases, and provide new insight into future directions and new strategies for laboratory research and clinical applications.

Circular RNA circ_0002594 regulates PDGF-BB-induced proliferation and migration of human airway smooth muscle cells via sponging miR-139-5p/TRIM8 in asthma

BACKGROUND

Asthma is a chronic respiratory disease characterised by the contraction of smooth muscle and remodelling of the airway wall, which is correlated with increased airway smooth muscle mass. Circular RNA (circRNA) circ_0002594 has been reported as a pro-inflammatory factor in allergic asthma. Therefore, this study is designed to explore the role and mechanism of circ_0002594 in human airway smooth muscle cells (HASMC) proliferation and metastasis.

METHODS

Cell proliferative ability, invasion, and migration were detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), Transwell, and Wound healing assays. The protein levels of E-cadherin, N-cadherin, and tripartite motif 8 (TRIM8) were detected by western blot assay. The levels of interleukin-6 (IL-6) and IL-13 were detected using Enzyme-linked immunosorbent assays (ELISA). Levels of circ_0002594, microRNA-139-5p (miR-139-5p), TRIM8 were determined by real-time quantitative polymerase chain reaction (RT-qPCR). The binding between miR-139-5p and circ_0002594 or TRIM8 was predicted by Circinteractome or Starbase v2.0, and then verified by a dual-luciferase reporter and RNA Immunoprecipitation (RIP) assays.

RESULTS

Platelet-derived growth factor-BB (PDGF-BB) could trigger HASMC proliferation, metastasis, and inflammation. Circ_0002594 and TRIM8 were elevated in asthma patients and PDGF-BB-treated HASMC, and the miR-139-5p level was decreased. Furthermore, circ_0002594 knockdown could suppress PDGF-BB- stimulated HASMC damage. Mechanism analysis exhibited that circ_0002594 could regulate TRIM8 expression through sponging miR-139-5p.

CONCLUSION

Our findings revealed that circ_0002594 could act as a regulator in the airway remodelling during asthma development partly by the miR-139-5p/TRIM8 axis, hinting at an underlying therapeutic strategy for asthma.

Emerging Roles of Non-Coding RNAs in Childhood Asthma

Asthma is a chronic airway inflammatory disease in children characterized by airway inflammation, airway hyperresponsiveness and airway remodeling. Childhood asthma is usually associated with allergy and atopy, unlike adult asthma, which is commonly associated with obesity, smoking, etc. The pathogenesis and diagnosis of childhood asthma also remains more challenging than adult asthma, such as many diseases showing similar symptoms may coexist and be confused with asthma. In terms of the treatment, although most childhood asthma can potentially be self-managed and controlled with drugs, approximately 5-10% of children suffer from severe uncontrolled asthma, which carries significant health and socioeconomic burdens. Therefore, it is necessary to explore the pathogenesis of childhood asthma from a new perspective. Studies have revealed that non-coding RNAs (ncRNAs) are involved in the regulation of respiratory diseases. In addition, altered expression of ncRNAs in blood, and in condensate of sputum or exhalation affects the progression of asthma via regulating immune response. In this review, we outline the regulation and pathogenesis of asthma and summarize the role of ncRNAs in childhood asthma. We also hold promise that ncRNAs may be used for the development of biomarkers and support a new therapeutic strategy for childhood asthma.

Emerging Advances of Non-coding RNAs and Competitive Endogenous RNA Regulatory Networks in Asthma

Asthma is a chronic inflammatory disease characterized by airway remodeling and bronchial hyperresponsiveness. A variety of effector cells and cytokines jointly stimulate the occurrence of inflammatory response in asthma. Although the pathogenesis of asthma is not entirely clear, the possible roles of non-coding RNAs (ncRNAs) have been recently demonstrated. NcRNAs are non-protein-coding RNA molecules, such as circular RNAs (circRNAs), long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), which are involved in the regulation of a variety of biological processes. Mounting studies have shown that ncRNAs play pivotal roles in the occurrence and progression of asthma via competing endogenous RNA (ceRNA) regulatory networks. However, the specific mechanism and clinical application of ncRNAs and ceRNA regulatory networks in asthma have not been fully elucidated, which are worthy of further investigation. This paper comprehensively summarized the current progress on the roles of miRNAs, lncRNAs, circRNAs, and ceRNA regulatory networks in asthma, which can provide a better understanding for the disease pathogenesis and is helpful for identifying novel biomarkers for asthma.

Identification of circular RNA circVPS33A as a modulator in house dust mite-induced injury in human bronchial epithelial cells

BACKGROUND

House dust mite has been well documented as a major source of allergen in asthma. Circular RNAs (circRNAs) vacuolar protein sorting 33A (circVPS33A, circ_0000455) is overexpressed in a murine asthma model. Herein, we sought to identify its critical action in Dermatophagoides pteronyssinus peptidase 1 (Der p1)-induced dysfunction of BEAS-2B cells.

METHODS

The levels of circVPS33A, microRNA (miR)-192-5p, and high-mobility group box 1 (HMGB1) were assessed by quantitative real-time PCR (qRT-PCR) or western blot. Actinomycin D treatment and Ribonuclease R (RNase R) assay were used to characterize circVPS33A. Cell viability, proliferation, apoptosis, migration, and invasion were evaluated by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, and transwell assays, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to quantify interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-6. Direct relationship between miR-192-5p and circVPS33A or HMGB1 was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assay.

RESULTS

CircVPS33A was highly expressed in asthma plasma and Der p1-treated BEAS-2B cells. Knocking down circVPS33A suppressed Der p1-induced injury in BEAS-2B cells. CircVPS33A targeted miR-192-5p. MiR-192-5p directly targeted HMGB1, and miR-192-5p-mediated repression of HMGB1 alleviated Der p1-driven cell injury. Furthermore, circVPS33A modulated HMGB1 expression through miR-192-5p.

CONCLUSION

Our findings demonstrated that circVPS33A regulated house dust mite-induced injury in human bronchial epithelial cells at least partially depending on the modulation of the miR-192-5p/HMGB1 axis.

Recent research progress on circular RNAs: Biogenesis, properties, functions, and therapeutic potential

Circular RNAs (circRNAs), an emerging family member of RNAs, have gained importance in research due to their new functional roles in cellular physiology and disease progression. circRNAs are usually available in a wide range of cells and have shown tissue-specific expression as well as developmental specific expression. circRNAs are characterized by structural stability, conservation, and high abundance in the cell. In this review, we discuss the different models of biogenesis. The properties of circRNAs such as localization, structure and conserved pattern, stability, and expression specificity are also been illustrated. Furthermore, we discuss the biological functions of circRNAs such as microRNA (miRNA) sponging, cell cycle regulation, cell-to-cell communication, transcription regulation, translational regulation, disease diagnosis, and therapeutic potential. Finally, we discuss the recent research progress and future perspective of circRNAs. This review provides an understanding of potential diagnostic markers and the therapeutic potential of circRNAs, which are emerging daily.

Silencing of circHIPK3 hampers platelet-derived growth factor-induced proliferation and migration in airway smooth muscle cells through the miR-375/MMP-16 axis

Emerging evidence has suggested a pivotal role of circular RNAs (circRNAs) in the progression of asthma. In this paper, we explored the mechanisms underlying the modulation of circRNA homeodomain interacting protein kinase 3 (circHIPK3, circ_0000284) in airway smooth muscle cell (AMSC) migration and proliferation induced by platelet-derived growth factor (PDGF). The stability of circHIPK3 was gauged by Ribonuclease R (RNase R) and Actinomycin D assays. Relative expression levels of circHIPK3, microRNA (miR)-375 and matrix metallopeptidase 16 (MMP-16) were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Cell proliferation, invasion, and apoptosis were evaluated by Cell Counting Kit-8 (CCK-8) assay, transwell assay, and flow cytometry, respectively. Cell migration was detected by wound-healing and transwell assays. Direct relationship between miR-375 and circHIPK3 or MMP-16 was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Our results indicated that PDGF induced the expression of circHIPK3 in human AMSCs (HAMSCs). CircHIPK3 silencing impeded proliferation, migration, invasion and promoted apoptosis of PDGF-treated HAMSCs. Mechanistically, circHIPK3 targeted miR-375 by directly binding to miR-375. MiR-375 was a downstream effector of circHIPK3 in controlling PDGF-induced proliferation, invasion and migration. MMP-16 was directly targeted and inhibited by miR-375, and circHIPK3 functioned as a post-transcriptional modulator of MMP-16 expression through miR-375. Moreover, miR-375-mediated inhibition of MMP-16 impacted HAMSC proliferation, invasion and migration induced by PDGF. Our findings identified the miR-375/MMP-16 axis as a novel mechanism for the modulation of circHIPK3 in PDGF-induced migration and proliferation in HASMCs.

Current Understanding of Circular RNAs in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a common and potentially fatal autoimmune disease that affects multiple organs. To date, its etiology and pathogenesis remains elusive. Circular RNAs (circRNAs) are a novel class of endogenous non-coding RNAs with covalently closed loop structure. Growing evidence has demonstrated that circRNAs may play an essential role in regulation of gene expression and transcription by acting as microRNA (miRNA) sponges, impacting cell survival and proliferation by interacting with RNA binding proteins (RBPs), and strengthening mRNA stability by forming RNA-protein complexes duplex structures. The expression patterns of circRNAs exhibit tissue-specific and pathogenesis-related manner. CircRNAs have implicated in the development of multiple autoimmune diseases, including SLE. In this review, we summarize the characteristics, biogenesis, and potential functions of circRNAs, its impact on immune responses and highlight current understanding of circRNAs in the pathogenesis of SLE.