The emerging roles and functions of circular RNAs and their generation

Update in the molecular mechanism and biomarkers of diabetic retinopathy

Diabetic retinopathy (DR) is a serious complication of diabetes caused by long-term hyperglycemia that leads to microvascular and neuronal damage in the retina. The molecular mechanisms of DR involve oxidative stress, inflammatory responses, neurodegenerative changes, and vascular dysfunction triggered by hyperglycemia. Oxidative stress activates multiple metabolic pathways, such as the polyol, hexosamine, and protein kinase C (PKC) pathways, resulting in the production of, which in turn promote the formation of advanced glycation end products (AGEs). These pathways exacerbate vascular endothelial damage and the release of inflammatory factors, activating inflammatory signaling pathways such as the NF-κB pathway, leading to retinal cell damage and apoptosis. Additionally, DR involves neurodegenerative changes, including the activation of glial cells, neuronal dysfunction, and cell death. Research on the multiomics molecular markers of DR has revealed complex mechanisms at the genetic, epigenetic, and transcriptional levels. Genome-wide association studies (GWASs) have identified multiple genetic loci associated with DR that are involved in metabolic and inflammatory pathways. Noncoding RNAs, such as miRNAs, circRNAs, and lncRNAs, participate in the development of DR by regulating gene expression. Proteomic, metabolomic and lipidomic analyses have revealed specific proteins, metabolites and lipid changes associated with DR, providing potential biomarkers for the early diagnosis and treatment of this disease. This review provides a comprehensive perspective for understanding the molecular network of DR and facilitates the exploration of innovative therapeutic approaches.

Frequent dysregulation of multiple circular RNA isoforms with diverse regulatory mechanisms in cancer - Insights from circFNDC3B and beyond: Why unique circular RNA identifiers matter

Circular RNAs (circRNAs) are post-transcriptional regulators generated through backsplicing of pre-mRNAs, primarily comprising exons of host genes. A single host gene may produce multiple circRNA isoforms with distinct structures and sequences. Dysregulated circRNA expression has been implicated in tumorigenesis. This review aims to investigate the selection and regulatory roles of circRNA isoforms in cancer using the extensively studied hsa_circFNDC3B and thirteen other circRNAs as study models. Interrogation of literature and databases, particularly the circBase, confirms that host genes generate a plethora of circRNA isoforms; however, only a small subset of isoforms is validated as dysregulated in tumor tissues. Notably, two or more isoforms of the same circRNA are frequently dysregulated in cancer. Structurally, short isoforms retaining 5'-proximal exons are preferentially selected, but for long host genes, circRNAs may arise from mid- or 3'-regions. We identify dysregulation of seven circFNDC3B isoforms across twelve cancer types and multi-isoforms in nine of the other thirteen circRNAs also in multiple cancers. MicroRNA sponging appears to be the major regulatory mechanism, but possible biased study designs raise concerns. Using circFNDC3B and circZFR as examples, we show inconsistency and inadequacy in circRNA nomenclature in different databases and the literature, underscoring the urgent need for a universally accepted standardized central circRNA database. As an interim measure, we propose guidelines for circRNA nomenclature in journal publications. Our findings caution against indiscriminate clinical use of specific circRNA isoforms as biomarkers or therapeutic targets without further validation.

Cigarette smoke alters circRNA expression in human T-cells

Circular RNAs (circRNAs), once thought to be a result of splicing errors, have been found to be involved in various molecular processes and the pathology of various diseases, including cancer and neurodegenerative diseases. Additionally, circRNA expression was found to be altered by lifestyle habits, such as smoking cigarettes. Past studies have revealed that the rate of smoking remains high in people living with human immunodeficiency virus (HIV). In this study, we isolated total RNA from uninfected T-cells that have been exposed to cigarette smoke and compared the expression levels of circRNAs to those of T-cells that were not exposed to cigarette smoke. We identified certain circRNAs that were upregulated or downregulated in T-cells when exposed to cigarette smoke. These data indicate that the study of circRNAs is warranted within the context of HIV.

Quaking RNA-Binding protein (QKI) mediates circular RNA biogenesis in Litopenaeus vannamei during WSSV infection

The Quaking RNA-binding protein (QKI), a member of the STAR family, is considered critical in the formation of circular RNAs (circRNAs), as it aids in catalyzing a back-splicing phenomenon by interacting with RNA precursors. CircRNAs have progressively been revealed to play central roles in the regulation of various biological processes, such as antiviral defense mechanisms. This study identifies a QKI in L. vannamei, referred to as LvQKI, comprised of conserved STAR and KH RNA-binding domains. Analysis through tissue-specific expression using qRT-PCR has revealed a high expression level of LvQKI in the gill - one of the primary regions heavily populated by the white spot syndrome virus (WSSV) - and its activation was triggered during WSSV infection. From an RNA interference-mediated suppression targeting LvQKI, a decrease and increase in survival rates and WSSV copy number were observed, respectively. Notably, circRNA levels were significantly lowered in LvQKI-silenced shrimp, whereas linear RNAs remained stable. Conversely, administration of recombinant LvQKI (rLvQKI) protein before a WSSV challenge not only enhanced survival rates but also reduced viral load, wherein both circRNAs and linear RNAs underwent up-regulation in rLvQKI-treated shrimp. Our results introduce LvQKI as a crucial factor in circRNA biogenesis and immune defense in shrimp, emphasizing the interplay between LvQKI's and circRNAs' roles in fighting viral invasion.

Circular RNAs in neurological conditions - computational identification, functional validation, and potential clinical applications

Non-coding RNAs (ncRNAs) have gained significant attention in recent years due to advancements in biotechnology, particularly high-throughput total RNA sequencing. These developments have led to new understandings of non-coding biology, revealing that approximately 80% of non-coding regions in the genome possesses biochemical functionality. Among ncRNAs, circular RNAs (circRNAs), first identified in 1976, have emerged as a prominent research field. CircRNAs are abundant in most human cell types, evolutionary conserved, highly stable, and formed by back-splicing events which generate covalently closed ends. Notably, circRNAs exhibit high expression levels in neural tissue and perform diverse biochemical functions, including acting as molecular sponges for microRNAs, interacting with RNA-binding proteins to regulate their availability and activity, modulating transcription and splicing, and even translating into functional peptides in some cases. Recent advancements in computational and experimental methods have enhanced our ability to identify and validate circRNAs, providing valuable insights into their biological roles. This review focuses on recent developments in circRNA research as they related to neuropsychiatric and neurodegenerative conditions. We also explore their potential applications in clinical diagnostics, therapeutics, and future research directions. CircRNAs remain a relatively underexplored area of non-coding biology, particularly in the context of neurological disorders. However, emerging evidence supports their role as critical players in the etiology and molecular mechanisms of conditions such as schizophrenia, bipolar disorder, major depressive disorder, Alzheimer's disease, and Parkinson's disease. These findings suggest that circRNAs may provide a novel framework contributing to the molecular dysfunctions underpinning these complex neurological conditions.

Mechanisms of apoptosis-related non-coding RNAs in ovarian cancer: a narrative review

Ovarian cancer remains a major challenge in oncology due to its complex biology and late-stage diagnosis. Recent advances in molecular biology have highlighted the crucial role of non-coding RNAs (ncRNAs) in regulating apoptosis and cancer progression. NcRNAs, including microRNAs, long non-coding RNAs, and circular RNAs, have emerged as significant players in the molecular networks governing ovarian cancer. Despite these insights, the precise mechanisms by which ncRNAs influence ovarian cancer pathology are not fully understood. This complexity, combined with the heterogeneity of the disease and the development of treatment resistance, poses substantial obstacles to effective therapeutic development. Additionally, the lack of reliable early detection methods further complicates treatment strategies. This manuscript reviews the current state of research on ncRNAs in ovarian cancer, discusses the challenges in translating these findings into clinical applications, and outlines potential future directions. Emphasis is placed on the need for integrated approaches to unravel the intricate roles of ncRNAs, improve early detection, and develop personalized treatment strategies to address the diverse and evolving nature of ovarian cancer. While these findings provide valuable insights, it is crucial to recognize that many results are based on preclinical studies and require further validation to establish their clinical applicability.

Circular RNAs: driving forces behind chemoresistance and immune evasion in bladder cancer

Bladder cancer (BCa) is characterized by recurring relapses and the emergence of chemoresistance, especially against standard treatments like cisplatin and gemcitabine. Despite its significance, the molecular mechanisms underlying chemoresistance in BCa remain elusive. Recent studies have revealed that circular RNAs (circRNAs) are pivotal regulators of cancer progression and chemoresistance. Through their function as miRNA sponges and protein sequesters, circRNAs modulate the expression of key genes, ultimately driving either drug resistance or sensitivity in BCa. The complex interplay between circRNAs and chemoresistance suggests that they may represent promising therapeutic targets for overcoming treatment resistance in patients with BCa. This review aims to summarize the current understanding of circRNAs' regulatory roles in chemoresistance and provide insights into their potential as therapeutic targets, particularly in the context of cisplatin and gemcitabine resistance. Furthermore, we explore how chemoresistance can also impact tumor immune evasion, thereby affecting the tumor microenvironment. Our findings may pave the way for the advancement of innovative treatment approaches for bladder cancer.

Non-coding RNAs: emerging biomarkers and therapeutic targets in cancer and inflammatory diseases

Non-coding RNAs (ncRNAs) have a significant role in gene regulation, especially in cancer and inflammatory diseases. ncRNAs, such as microRNA, long non-coding RNAs, and circular RNAs, alter the transcriptional, post-transcriptional, and epigenetic gene expression levels. These molecules act as biomarkers and possible therapeutic targets because aberrant ncRNA expression has been directly connected to tumor progression, metastasis, and response to therapy in cancer research. ncRNAs' interactions with multiple cellular pathways, including MAPK, Wnt, and PI3K/AKT/mTOR, impact cellular processes like proliferation, apoptosis, and immune responses. The potential of RNA-based therapeutics, such as anti-microRNA and microRNA mimics, to restore normal gene expression is being actively studied. Additionally, the tissue-specific expression patterns of ncRNAs offer unique opportunities for targeted therapy. Specificity, stability, and immune responses are obstacles to the therapeutic use of ncRNAs; however, novel strategies, such as modified oligonucleotides and targeted delivery systems, are being developed. ncRNA profiling may result in more individualized and successful treatments as precision medicine advances, improving patient outcomes and creating early diagnosis and monitoring opportunities. The current review aims to investigate the roles of ncRNAs as potential biomarkers and therapeutic targets in cancer and inflammatory diseases, focusing on their mechanisms in gene regulation and their implications for non-invasive diagnostics and targeted therapies. A comprehensive literature review was conducted using PubMed and Google Scholar, focusing on research published between 2014 and 2025. Studies were selected based on rigorous inclusion criteria, including peer-reviewed status and relevance to ncRNA roles in cancer and inflammatory diseases. Non-English, non-peer-reviewed, and inconclusive studies were excluded. This approach ensures that the findings presented are based on high-quality and relevant sources.

Emerging roles of noncoding RNAs in cardiovascular pathophysiology

This review comprehensively examines the diverse roles of noncoding RNAs (ncRNAs) in the pathogenesis and treatment of cardiovascular disease (CVD), focusing on microRNA (miRNA), long noncoding RNA (lncRNA), piwi-interacting RNA (piRNA), small-interfering RNA (siRNA), circular RNA (circRNA), and vesicle-associated RNAs. These ncRNAs are integral regulators of key cellular processes, including gene expression, inflammation, and fibrosis, and they hold great potential as both diagnostic biomarkers and therapeutic targets. The review highlights novel insights into how these RNA species, particularly miRNAs, lncRNAs, and piRNAs, contribute to various CVDs such as hypertension, atherosclerosis, and myocardial infarction. In addition, it explores the emerging role of extracellular vesicles (EVs) in intercellular communication and their therapeutic potential in cardiovascular health. The review underscores the need for continued research into ncRNAs and RNA-based therapies, with a focus on advancing delivery systems and expanding personalized medicine approaches to improve cardiovascular outcomes.

5-Methylcytosine-modified circRNA-CCNL2 regulates vascular remdeling in hypoxic pulmonary hypertension through binding to FXR2

Pulmonary hypertension (PH) is a malignant cardiovascular disease with a complex etiology. 5-Methylcytosine (m5C) is a post-transcriptional RNA modification identified in both stable and highly abundant RNAs, with a lower frequency of occurrence in circular RNAs (circRNAs). Nevertheless, the function of m5C-modified circRNAs in the pathogenesis of PH remains uncertain. The objective of this study was to investigate the biological role and molecular mechanisms of m5C-modified circRNA-CCNL2 in hypoxic PH pulmonary vascular remodeling. Our findings revealed that hypoxia downregulates circCCNL2 expression, and overexpression of circCCNL2 attenuates PH progression and inhibits the proliferation of pulmonary artery smooth muscle cell (PASMCs). Bioinformatics predictions indicated the presence of m5C modification sites in circCCNL2, which NSUN2 mediated. The downregulation of NSUN2 resulted in a reduction in m5C modification of circCCNL2. It was also observed that the stability of circRNAs was associated with the proliferation of PASMCs. From a mechanistic standpoint, low expression of circCCNL2 resulted in reduced binding of FXR2, while increased association of free FXR2 with CDKL3 led to enhanced proliferation of PASMCs. Notably, circCCNL2 expression was found to be regulated by alternative splicing involving SRSF2, with reduced pre-CCNL2 splicing resulting from low SRSF2 expression, ultimately leading to decreased circCCNL2 expression. This is the first demonstration that m5C-modified circCCNL2 can slow the development of PH and inhibit the proliferation of PASMCs by binding to FXR2. These findings offer new insights into the regulation of circRNAs through m5C modifications and the role of epigenetic reprogramming in PH.

Role of circRNAs in regulating cell death in cancer: a comprehensive review

Despite multiple diagnostic and therapeutic advances, including surgery, radiation therapy, and chemotherapy, cancer preserved its spot as a global health concern. Prompt cancer diagnosis, treatment, and prognosis depend on the discovery of new biomarkers and therapeutic strategies. Circular RNAs (circRNAs) are considered as a stable, conserved, abundant, and varied group of RNA molecules that perform multiple roles such as gene regulation. There is evidence that circRNAs interact with RNA-binding proteins, especially capturing miRNAs. An extensive amount of research has presented the substantial contribution of circRNAs in various types of cancer. To fully understand the linkage between circRNAs and cancer growth as a consequence of various cell death processes, including autophagy, ferroptosis, and apoptosis, more research is necessary. The expression of circRNAs could be controlled to limit the occurrence and growth of cancer, providing a more encouraging method of cancer treatment. Consequently, it is critical to understand how circRNAs affect various forms of cancer cell death and evaluate whether circRNAs could be used as targets to induce tumor death and increase the efficacy of chemotherapy. The current study aims to review and comprehend the effects that circular RNAs exert on cell apoptosis, autophagy, and ferroptosis in cancer to investigate potential cancer treatment targets.

ncRNAs-Mediated Pyroptosis in Cerebral Ischemia-Reperfusion Injury: Pathophysiology, Mechanisms, and Therapeutic Perspectives

Cerebral ischemia-reperfusion injury (CIRI) is a complex pathological process triggered by transient obstruction of blood flow and subsequent reperfusion, ultimately leading to intracellular disturbances such as oxidative stress, inflammatory responses, and programmed cell death. Among the various types of cell death, pyroptosis (an inflammatory kind of regulated cell death) has received increasing attention due to its involvement in key neurovascular unit cells, including endothelial cells, neurons, microglia, and astrocytes. Intriguingly, accumulating evidence demonstrates that non-coding RNAs (ncRNAs), including long non-coding RNAs, microRNAs, and circular RNAs, can modulate multiple stages of pyroptosis in CIRI. This review synthesizes recent findings on the ncRNAs-regulated pyroptosis in CIRI. We highlight the molecular underpinnings of pyroptotic activation following ischemic injury and discuss how ncRNAs shape these mechanisms. By elucidating the interactions between ncRNAs and pyroptosis-related pathways, we intend to present innovative viewpoints for early diagnosis and the development of potential therapeutic strategies to mitigate CIRI.

Machine Learning-Enabled Non-Invasive Screening of Tumor-Associated Circulating Transcripts for Early Detection of Colorectal Cancer

Colorectal cancer (CRC) is a major cause of cancer-related mortality, highlighting the need for accurate and non-invasive diagnostics. This study assessed the utility of tumor-associated circulating transcripts (TACTs) as biomarkers for CRC detection and integrated these markers into machine learning models to enhance diagnostic performance. We evaluated five models-Generalized Linear Model, Random Forest, Gradient Boosting Machine, Deep Neural Network (DNN), and AutoML-and identified the DNN model as optimal owing to its high sensitivity (85.7%) and specificity (90.9%) for CRC detection, particularly in early-stage cases. Our findings suggest that combining TACT markers with AI-based analysis provides a scalable and precise approach for CRC screening, offering significant advancements in non-invasive cancer diagnostics to improve early detection and patient outcomes.

Circular RNA microarray expression profile and potential function of circDOCK1 in colorectal cancer

Introduction

Endoscopic tissue biopsy combined with histopathology is the gold standard for the diagnosis of colorectal cancer (CRC); however, the invasive nature of this procedure hinders its acceptance by patients. Therefore, there exists a critical need to identify novel markers facilitating early CRC detection and prognosis. Circular RNAs (circRNAs) hold promise as novel clinical diagnostic markers. This study aimed to investigate the impact of circDOCK1 on CRC metastasis and prognosis as well as its underlying molecular mechanisms.

Methods

We explored circRNA expression profiles in four pairs of CRC tissues and adjacent non-carcinoma tissues via microarray analysis. After Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and circRNA-miRNA network analyses, circDOCK1 was chosen for further investigation. We evaluated its clinical relevance in 80 CRC tissue pairs and adjacent controls, correlating circDOCK1 expression with clinical characteristics. Follow-up data from patient telephone interviews were analyzed for survival outcomes. Transfection efficiency was confirmed via qRT-PCR in HCT116 and SW480 colon cells, and the effects of circDOCK1 on cell proliferation, migration, and invasion were assessed.

Results

Microarray data revealed 149 significantly differentially expressed circRNAs, including 71 upregulated and 78 downregulated circRNAs, in CRC tissues. CircDOCK1 exhibited elevated expression in patients with CRC and emerged as an independent prognostic factor. Kaplan-Meier curve analysis suggested that circDOCK1 expression is an unfavorable prognostic factor in patients with CRC. In vivo experiments revealed that circDOCK1 overexpression enhanced the proliferation, migration, and invasion of CRC cells, with consistent results upon circDOCK1 downregulation.

Conclusion

These data indicate that circDOCK1 may play a role in promoting the proliferation, migration, and invasion of CRC cells, suggesting its potential as a CRC biomarker.

Regulation of energy metabolism by non-coding RNAs in livestock species: a review

The optimisation of livestock production relies on efficient energy metabolism. This review focused on elaborate regulatory processes governed by non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). It explores the complex energy metabolism processes in livestock, elucidating the functions of ncRNAs in the expression of genes and pathways. miRNAs have been identified as significant regulators of glycolysis and glucose metabolism, whereas lncRNAs are known to affect adipogenesis and mitochondrial activity. Moreover, circRNAs have a substantial influence on the regulation of energy. In addition, this is not only enriching non-coding RNA-mediated energy control but also sheds light on possible applications. It is derived from its ability to condense complex molecular systems, thereby offering crucial insights to researchers. Through a comprehensive analysis of the intricate relationship between ncRNAs and energy metabolism, the information of this review provides a valuable framework for the implementation of focused interventions that hold the potential to significantly enhance the efficiency of livestock production.

CellCircLoc: Deep Neural Network for Predicting and Explaining Cell Line-Specific CircRNA Subcellular Localization

The subcellular localization of circular RNAs (circRNAs) is crucial for understanding their functional relevance and regulatory mechanisms. CircRNA subcellular localization exhibits variations across different cell lines, demonstrating the diversity and complexity of circRNA regulation within distinct cellular contexts. However, existing computational methods for predicting circRNA subcellular localization often ignore the importance of cell line specificity and instead train a general model on aggregated data from all cell lines. Considering the diversity and context-dependent behavior of circRNAs across different cell lines, it is imperative to develop cell line-specific models to accurately predict circRNA subcellular localization. In the study, we proposed CellCircLoc, a sequence-based deep learning model for circRNA subcellular localization prediction, which is trained for different cell lines. CellCircLoc utilizes a combination of convolutional neural networks, Transformer blocks, and bidirectional long short-term memory to capture both sequence local features and long-range dependencies within the sequences. In the Transformer blocks, CellCircLoc uses an attentive convolution mechanism to capture the importance of individual nucleotides. Extensive experiments demonstrate the effectiveness of CellCircLoc in accurately predicting circRNA subcellular localization across different cell lines, outperforming other computational models that do not consider cell line specificity. Moreover, the interpretability of CellCircLoc facilitates the discovery of important motifs associated with circRNA subcellular localization.

Metabolic reprogramming and signaling adaptations in anoikis resistance: mechanisms and therapeutic targets

Anoikis, a form of programmed cell death triggered by detachment from the extracellular matrix (ECM), maintains tissue homeostasis by removing mislocalized or detached cells. Cancer cells, however, have evolved multiple mechanisms to evade anoikis under conditions of ECM detachment, enabling survival and distant metastasis. Studies have identified differentially expressed proteins between suspended and adherent cancer cells, revealing that key metabolic and signaling pathways undergo significant alterations during the acquisition of anoikis resistance. This review explores the regulatory roles of epithelial-mesenchymal transition, cancer stem cell characteristics, metabolic reprogramming, and various signaling pathway alterations in promoting anoikis resistance. And the corresponding reagents and non-coding RNAs that target the aforementioned pathways are reviewed. By discussing the regulatory mechanisms that facilitate anoikis resistance in cancer cells, this review aims to shed light on potential strategies for inhibiting tumor progression and preventing metastasis.

Full-length nanopore sequencing of circular RNA landscape in peripheral blood cells following sequential BNT162b2 mRNA vaccination

Circular RNAs (circRNA) lack 5' or 3' ends; their unique covalently closed structures prevent RNA degradation by exonucleases. These characteristics provide circRNAs with high pharmaceutical stability and biostability relative to current standard-of-care linear mRNAs. CircRNA levels are reportedly associated with certain human diseases, making them novel disease biomarkers and a noncanonical class of therapeutic targets. In this study, the endogenous circRNAs underlying the response to BNT162b2 mRNA vaccination were evaluated. To this end, peripheral blood samples were subjected to full-length sequencing of circRNAs via nanopore sequencing and transcriptome sequencing. Fifteen samples, comprising pre-, first, and second vaccination cohorts, were obtained from five healthcare workers with no history of SARS-CoV-2 infection or previous vaccination. A total of 4706 circRNAs were detected; following full-length sequencing, 4217 novel circRNAs were identified as being specifically expressed during vaccination. These circRNAs were enriched in the binding motifs of stress granule assemblies and SARS-CoV-2 RNA binding proteins, namely poly(A) binding protein cytoplasmic 1 (PABPC1), pumilio RNA binding family member 1 (PUM1), and Y box binding protein 1 (YBX1). Moreover, 489 circRNAs were identified as previously reported miRNA sponges. The differentially expressed circRNAs putatively originated from plasma B cells compared to circRNAs reported in human blood single-cell RNA sequencing datasets. The pre- and post-vaccination differences observed in the circRNA expression landscape in response to the SARS-CoV-2 BNT162b2 mRNA vaccine.

Evaluation of circ_0002232 and circ-vimentin gene expressions as valuable biomarkers in acute myeloid leukemia patients

BACKGROUND AND AIM

Acute myeloid leukemia (AML) is a remarkably complex malignancy; with considerable genetic, epigenetic, and phenotypic heterogenicity. Circ-RNAs are a novel class of non-coding RNA. They may influence leukemia development and offer exciting possibilities for targeted AML diagnosis and therapy. This study aimed to detect circ_0002232 and circ-VIM expression levels in AML patients and their relation to the clinicopathological characteristics and disease outcome to assess the prognostic potential of both circ-RNAs and achieve a new target therapy for the disease.

METHODS

Circ_0002232 and circ-VIM gene expressions were measured in 60 AML patients and 30 controls using qRT-PCR.

RESULTS

Circ_0002232 was significantly downregulated in our patients compared to controls (P value < 0.001). On the other hand, circ-VIM was notably upregulated in our patients (P value = 0.005). Using ROC curve, circ_0002232 and circ-VIM biomarkers could distinguish AML patients from controls with AUC 0.847, 0.683 and P value < 0.0001, = 0.004 respectively. Patients with downregulated circ_0002232 were significantly younger than upregulated patients (p value = 0.003). In addition, downregulated circ_0002232 was significantly associated with decreased hemoglobin level and increased overall survival (OS). Regarding high circ-VIM expression in AML patients, it was significantly correlated with lacking complete remission and leukocytosis.

CONCLUSION

Circ_0002232 and circ-VIM could be valuable diagnostic biomarkers to differentiate AML patients from healthy controls in clinical use. Circ-VIM expression may influence AML prognosis. Further research is needed to validate the clinical utility of circ_0002232 as a prognostic marker for OS in AML patients.

Epigenetic Insights into Substance Use Disorder and Associated Psychiatric Conditions

Background

Substance use disorder (SUD) is closely associated with epigenetic modifications that significantly impact mental health outcomes. Alcohol and drug misuse induce widespread changes in the epigenome and transcriptome of the central nervous system, disrupting critical processes such as reward signaling and emotional regulation. These alterations in epigenetic regulation and gene expression often persist even after substance cessation, potentially contributing to the onset or worsening of psychiatric conditions, including schizophrenia, depression, stress, and anxiety.

Summary

This review delves into key epigenetic mechanisms underlying SUD and its comorbid psychiatric disorders, with a focus on DNA methylation, histone modifications, and noncoding RNA regulation. Additionally, it examines the influence of environmental and biological factors on the epigenome and evaluates emerging epigenetic-based therapeutic strategies aimed at treating SUD and related psychiatric conditions.

Key Messages

Gaining a deeper understanding of the epigenetic mechanisms driving SUD and its associated psychiatric disorders is crucial for the development of effective therapeutic interventions. This review highlights the potential of epigenetic-based pharmacological strategies to mitigate the societal and personal burdens linked to SUD and its mental health complications.

Circ_0096710 facilitates tumor growth via controlling ADAM10 expression in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a global cancer related to the sixth largest cause of death. Circular RNAs (circRNAs) have affected the progress of ESCC during recent years, but the mechanism is not completely clear. So here we probed the effects of hsa_circ_0096710 (circ_0096710) in ESCC.

METHODS

Relative levels of circ_0096710, miR-1294, and ADAM10 were quantified by the quantitative real-time reverse transcription-polymerase chain reaction in ESCC tissues. Western blot assessed ADAM10, PCNA, MMP2, VEGFA, and OCT4 protein levels. Cell proliferative capacity was assessed by cell counting and cell colony-forming assays. Transwell assays assessed cell migration and invasion. Angiogenesis was detected by tube formation assays. Stemness of cancer cells was estimated by sphere formation assays. Dual-luciferin reporter and RNA immunoprecipitation assays determined the targeting relationship between miR-1294 and circ_0096710 or ADAM10.

RESULTS

Relative levels of circ_0096710 and ADAM10 mRNA were upregulated in ESCC cells, yet miR-1294 was downregulated. Circ_0096710 silencing repressed ESCC cell proliferation, migration, invasion, angiogenesis, and stem-like properties. Moreover, circ_0096710 was an upstream target of miR-1294, and miR-1294 inhibition reversed the role of circ_0096710 downregulation in ESCC cells. Furthermore, ADAM10 was a downstream target of miR-1294, and miR-1294 overexpression suppressed ESCC cell proliferation, migration, invasion, angiogenesis, and stem-like properties by targeting ADAM10. Meanwhile, circ_0096710 upgraded ADAM10 expression through sponging miR-1294. Also, circ_0096710 downregulation restrained tumor growth in mouse models.

CONCLUSION

Circ_0096710 upregulates ADAM10 via mediating miR-1294 expression so as to accelerate the occurrence of ESCC, suggesting that circ_0096710 may be a potential therapeutic target for ESCC.

Non-coding RNAs and their potential exploitation in cancer therapy-related cardiotoxicity

Life expectancy in cancer patients has been extended in recent years, thanks to major breakthroughs in therapeutic developments. However, this also unmasked an increased incidence of cardiovascular diseases in cancer survivors, which is in part attributable to cancer therapy-related cardiovascular toxicity. Non-coding RNAs (ncRNAs) have received much appreciation due to their impact on gene expression. NcRNAs, which include microRNAs, long ncRNAs and circular RNAs, are non-protein-coding transcripts that are involved in the regulation of various biological processes, hence shaping cell identity and behaviour. They have also been implicated in disease development, including cardiovascular diseases, cancer and, more recently, cancer therapy-associated cardiotoxicity. This review outlines key features of cancer therapy-associated cardiotoxicity, what is known about the roles of ncRNAs in these processes and how ncRNAs could be exploited as therapeutic targets for cardioprotection. LINKED ARTICLES: This article is part of a themed issue Non-coding RNA Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.2/issuetoc.

Crosstalk between circular RNAs and the STAT3 signaling pathway in human cancer

Circular RNAs (circRNAs) are endogenous covalently closed single-stranded RNAs produced by reverse splicing of pre-mRNA. Emerging evidence suggests that circRNAs contribute to cancer progression by modulating the oncogenic STAT3 signaling pathway, which plays key roles in human malignancies. STAT3 signaling-related circRNAs expression appears to be extensively dysregulated in diverse cancer types, where they function either as tumor suppressors or oncogenes. However, the biological effects of STAT3 signaling-related circRNAs and their associations with cancer have not been systematically studied before. Given this, shedding light on the interaction between circRNAs and STAT3 signaling pathway in human malignancies may provide several novel insights into cancer therapy. In this review, we provide a comprehensive introduction to the molecular mechanisms by which circRNAs regulate STAT3 signaling in cancer progression, and the crosstalk between STAT3 signaling-related circRNAs and other signaling pathways. We also further discuss the role of the circRNA/STAT3 axis in cancer chemotherapy sensitivity.

Oxidative Stress-Associated Alteration of circRNA and Their ceRNA Network in Differentiating Neuroblasts

Oxidative stress from environmental exposures is thought to play a role in neurodevelopmental disorders; therefore, understanding the underlying molecular regulatory network is essential for mitigating its impacts. In this study, we analysed the competitive endogenous RNA (ceRNA) network mediated by circRNAs, a novel class of regulatory molecules, in an SH-SY5Y cell model of oxidative stress, both prior to and during neural differentiation, using RNA sequencing and in silico analysis. We identified 146 differentially expressed circRNAs, including 93 upregulated and 53 downregulated circRNAs, many of which were significantly co-expressed with mRNAs that potentially interact with miRNAs. We constructed a circRNA-miRNA-mRNA network and identified 15 circRNAs serving as hubs within the regulatory axes, with target genes enriched in stress- and neuron-related pathways, such as signaling by VEGF, axon guidance, signaling by FGFR, and the RAF/MAP kinase cascade. These findings provide insights into the role of the circRNA-mediated ceRNA network in oxidative stress during neuronal differentiation, which may help explain the regulatory mechanisms underlying neurodevelopmental disorders associated with oxidative stress.

Circular RNAs: novel noncoding players in male infertility

Infertility is a global problem being associated with emotional and financial burden. Recent studies have shown contribution of a group of non-coding RNAs, namely circular RNAs (circRNAs) to the etiology of some infertility conditions. CircRNA are transcribed from exons and form a circular RNA molecule, being abundant in eukaryotes. Traditionally classified as non-coding RNA, these transcripts are endogenously produced through either non-canonical back-splicing or linear splicing, typically produced from precursor messenger ribonucleic acid (pre-mRNA). While during the canonical splicing process the 3' end of the exon is joined to the 5' end of the succeeding exon to form linear mRNA, during backsplicing, the 3' end to the 5' end of the same exon is joined to make a circular molecule. circRNAs are involved in the regulation of several aspects of spermatogenesis. They appear to influence how stem germ cells grow and divide during the sperm production process. Malfunctions in circRNA activity could contribute to male infertility issues stemming from abnormalities in spermatogenesis. In the current review, we highlight the exciting potential of circRNAs as key players in the male fertility.

CircRSU1 contributes to the development of osteoarthritis via the miR-345-3p/TRAF6 signaling

OBJECTIVE

Osteoarthritis (OA) is a common type of prevalent joint diseases in the elderly. At present, circular RNAs receive more attention due to their roles during the progression of OA. In this paper, the expression profiles of circRSU1 and relevant molecules in OA patients and cell models were evaluated, and the underlying regulatory mechanisms of circRSU1-modulated OA development were also explored.

METHODS

The proliferation of chondrocytes was examined using CCK-8 assay. The levels of relevant proteins were evaluated by western blotting. The production of pro-inflammatory cytokines were measured by ELISA.

RESULTS

The results revealed upregulation of circRSU1 in OA samples, and IL-1β treatment could elevate the expression of circRSU1 in human chondrocytes. In addition, knockdown of circRSU1 abolished the dysfunctions caused by IL-1β in chondrocytes. Furthermore, miR-345-3p was identified as the novel downstream molecule of circRSU1. The levels of miR-345-3p were notably decreased in cells transfected with oe-circRSU1 and elevated in cells treated with si-circRSU1, respectively. Moreover, si-circRSU1 was able to attenuate IL-1β-induced impairments in chondrocyte via miR-345-3p. In addition, to verify the downstream mechanisms of circRSU1-modulated OA progression, TRAF6 was identified as the putative target of miR-345-3p, and miR-345-3p inhibition abolished circRSU1 knockdown-triggered downregulation of TRAF6 in IL-1β-induced OA cell model. In addition, miR-345-3p protected chondrocytes from IL-1β-induced dysfunction such as impaired ECM, reduced proliferation and upregulated apoptosis of chondrocytes, and elevated production of proinflammatory cytokines through regulating TRAF6.

CONCLUSION

In summary, circRSU1 was able to contribute to the progression of OA through regulating the miR-345-3p/TRAF6 pathway, and this novel signalling could be novel candidate for targeted therapy for OA patients.

Tumor Biology Hides Novel Therapeutic Approaches to Diffuse Large B-Cell Lymphoma: A Narrative Review

Diffuse large B-cell lymphoma (DLBCL) is a malignancy of immense biological and clinical heterogeneity. Based on the transcriptomic or genomic approach, several different classification schemes have evolved over the years to subdivide DLBCL into clinically (prognostically) relevant subsets, but each leaves unclassified samples. Herein, we outline the DLBCL tumor biology behind the actual and potential drug targets and address the challenges and drawbacks coupled with their (potential) use. Therapeutic modalities are discussed, including small-molecule inhibitors, naked antibodies, antibody-drug conjugates, chimeric antigen receptors, bispecific antibodies and T-cell engagers, and immune checkpoint inhibitors. Candidate drugs explored in ongoing clinical trials are coupled with diverse toxicity issues and refractoriness to drugs. According to the literature on DLBCL, the promise for new therapeutic targets lies in epigenetic alterations, B-cell receptor and NF-κB pathways. Herein, we present putative targets hiding in lipid pathways, ferroptosis, and the gut microbiome that could be used in addition to immuno-chemotherapy to improve the general health status of DLBCL patients, thus increasing the chance of being cured. It may be time to devote more effort to exploring DLBCL metabolism to discover novel druggable targets. We also performed a bibliometric and knowledge-map analysis of the literature on DLBCL published from 2014-2023.

CircLMBR1 inhibits phenotypic transformation of hypoxia-induced pulmonary artery smooth muscle via the splicing factor PUF60

Phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs) contributes to vascular remodeling in hypoxic pulmonary hypertension (PH). Recent studies have suggested that circular RNAs (circRNAs) may play important roles in the vascular remodeling of hypoxia-induced PH. However, whether circRNAs cause pulmonary vascular remodeling by regulating the phenotypic transformation in PH has not been investigated. Microarray and RT-qPCR analysis identified that circLMBR1, a novel circRNA, decreased in mouse lung tissues of the hypoxia-SU5416 PH model, as well as in human PASMCs and mouse PASMCs exposed to hypoxia. Overexpression of circLMBR1 in the Semaxinib (SU5416) mouse model ameliorated hypoxia-induced PH and vascular remodeling in the lungs. Notably, circLMBR1 was mainly distributed in the nucleus and bound to the splicing factor PUF60. CircLMBR1 suppressed the phenotypic transformation of human PASMCs and vascular remodeling by inhibiting PUF60 expression. Furthermore, we identified U2AF65 as the downstream regulatory factor of PUF60. U2AF65 directly interacted with the pre-mRNA of the contractile phenotype marker smooth muscle protein 22-α (SM22α) and inhibited its splicing. Meanwhile, hypoxia exposure increased the formation of the PUF60-U2AF65 complex, thereby inhibiting SM22α production and inducing the transition of human PASMCs from a contractile phenotype to a synthetic phenotype. Overall, our results verified the important role of circLMBR1 in the pathological process of PH. We also proposed a new circLMBR1/PUF60-U2AF65/pre-SM22α pathway that could regulate the phenotypic transformation and proliferation of human PASMCs. This study may provide new perspectives for the diagnosis and treatment of PH.

Circular RNAs as novel biomarkers in glomerular diseases

Circular RNAs (circRNAs) regulate gene expression and biological procedures by controlling target genes or downstream pathways by sponging their related miRNA (s). Three types of circRNAs have been identified; exonic circRNAs (ecircRNAs), intronic RNAs (ciRNAs), and exon-intron circRNAs (ElciRNAs). It is clarified that altered levels of circRNAs have dynamic pathological and physiological functions in kidney diseases. Evidence suggests that circRNAs can be considered novel diagnostic biomarkers and therapeutic targets for renal diseases. Glomerulonephritis (GN) is a general term used to refer to a wide range of glomerular diseases. GN is an important cause of chronic kidney diseases. Here, we review the biogenesis of circRNAs, and their molecular and physiological functions in the kidney. Moreover, the dysregulated expression of circRNAs and their biological functions are discussed in primary and secondary glomerulonephritis. Moreover, diagnostic and therapeutic values of circRNAs in distinguishing or treating different types of GN are highlighted.

Circ_0007422 Knockdown Inhibits Tumor Property and Immune Escape of Colorectal Cancer by Decreasing PDL1 Expression in a miR-1256-Dependent Manner

Circular RNAs (circRNAs) are a group of important molecules involved in the progression of various cancers, including colorectal cancer (CRC). Here, we aim to investigate the role and molecular mechanism of circ_0007422 in regulating CRC malignant progression. The expression levels of circ_0007422, miR-1256, and PDL1 were detected by qRT-PCR. Cell viability, proliferation, apoptosis, invasion, and self-replication ability were analyzed by CCK-8, EdU, flow cytometry, transwell, and spheroid formation experiments, respectively. Protein levels were determined by western blotting assay. CRC cells were co-cultured with CD8 + T cells, phytohemagglutinin-stimulated peripheral blood mononuclear cells (PBMCs), or cytokine-induced killer (CIK) cells in vitro, and CD8 + T-cell apoptosis, IFN-γ and TNF-α levels, and survival rate of CRC cells were analyzed to reveal the role of circ_0007422 in antitumor immunity. The relationship between miR-1256 and circ_0007422 or PDL1 was identified by a dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. A xenograft tumor model was established to verify the function of circ_0007422 in tumor growth in vivo. Immunohistochemistry (IHC) assay was used to detect positive expression rates of Ki67, E-cadherin, N-cadherin, and PDL1 expression in primary tumors from CRC cells. Circ_0007422 was upregulated in CRC tissues and cells and its knockdown inhibited proliferation, invasion, self-replication ability, and immune escape and promoted apoptosis of CRC cells. Additionally, circ_0007422 bound to miR-1256, which was identified to target PDL1. MiR-1256 inhibition reversed the effects of circ_0007422 knockdown on the tumor properties and immune escape of CRC cells. Moreover, miR-1256 introduction interacted with PDL1 to suppress proliferation, invasion, self-replication ability, and immune escape and promote apoptosis of CRC cells. Further, circ_0007422 knockdown hampered tumorigenesis of CRC cells in vivo. Circ_0007422 knockdown inhibited tumor property and immune escape of colorectal cancer through the miR-1256/PDL1 pathway, providing a potential novel therapeutic target for CRC.

The circular RNA circSLC16A10 alleviates diabetic retinopathy by improving mitochondrial function via the miR-761-5p/MFN2 axis

It has been demonstrated that circular RNAs (circRNAs) are associated with the development of diabetic retinopathy (DR). Nevertheless, the function of circSLC16A10 in the development of DR remains unclear. In order to investigate the role of circSLC16A10, we employed cell and animal models of DR. An analysis of a public database revealed that hsa_circSLC16A10 was expressed at lower levels in DR patients than in diabetic patients without DR or healthy controls. Additionally, the level of hsa_circSLC16A10 was lower in high glucose (HG)-exposed ARPE-19 cells and diabetic mice. hsa_circSLC16A10 was observed to be mainly distributed in the cytoplasm. Moreover, overexpression of hsa_circSLC16A10 alleviated HG-induced endoplasmic reticulum stress and cell apoptosis in vitro. Furthermore, overexpression of hsa_circSLC16A10 ameliorated HG-induced mitochondrial dysfunction, as evidenced by improvements in mitochondrial structure and function. hsa_circSLC16A10 acted as a hsa-miR-761-5p sponge to increase MFN2 expression. MFN2 knockdown or hsa-miR-761-5p overexpression partially reversed the protective effect of hsa_circSLC16A10 in vitro. The protective effect of mmu_circSLC16A10 against DR was confirmed in an animal model of DR. These findings indicate that circSLC16A10 may regulate DR progression by improving mitochondrial function via the miR-761-5p/MFN2 axis.

Exploring circular RNAs as biomarkers for Parkinson's disease and their expression changes after aerobic exercise rehabilitation

Circular RNAs (circRNAs) are circularized single-stranded ribonucleic acids that interacts with DNA, RNA, and proteins to play critical roles in cell biology. CircRNAs regulate microRNA content, gene expression, and may code for specific peptides. Indeed, circRNAs are differentially expressed in neurodegenerative disorders like Parkinson's disease (PD), playing a potential role in the mechanisms of brain pathology. The RNA molecules with aberrant expression in the brain can cross the blood-brain barrier and reach the bloodstream, which enable their use as non-invasive PD disease biomarker. Promising targets with valuable discriminatory ability in combined circRNA signatures include MAPK9_circ_0001566, SLAIN1_circ_0000497, SLAIN2_circ_0126525, PSEN1_circ_0003848, circ_0004381, and circ_0017204. On the other hand, regular exercises are effective therapy for mitigating PD symptoms, promoting neuroprotective effects with epigenetic modulation. Aerobic exercises slow symptom progression in PD by improving motor control, ameliorating higher functions, and enhancing brain activity and neuropathology. These improvements are accompanied by changes circRNA expression, including hsa_circ_0001535 (circFAM13B) and hsa_circ_0000437 (circCORO1C). The sensitivity of current methods for detecting circulating circRNAs is considered a limitation. While amplification kits already exist for low-abundant microRNAs, similar kits are needed for circRNAs. Alternatively, the use of digital PCR can help overcome this constraint. The current review examines the potential use of circRNAs as non-invasive biomarkers of PD and to assess the effects of rehabilitation. Although circRNAs hold promise as targets for PD diagnosis and therapeutics, further validation is needed before their clinical implementation.

A Comprehensive Insight and In Silico Analysis of CircRNAs in Hepatocellular Carcinoma: A Step toward ncRNA-Based Precision Medicine

Circular RNAs (circRNAs) are cardinal players in numerous physiological and pathological processes. CircRNAs play dual roles as tumor suppressors and oncogenes in different oncological contexts, including hepatocellular carcinoma (HCC). Their roles significantly impact the disease at all stages, including initiation, development, progression, invasion, and metastasis, in addition to the response to treatment. In this review, we discuss the biogenesis and regulatory functional roles of circRNAs, as well as circRNA-protein-mRNA ternary complex formation, elucidating the intricate pathways tuned by circRNAs to modulate gene expression and cellular processes through a comprehensive literature search, in silico search, and bioinformatics analysis. With a particular focus on the interplay between circRNAs, epigenetics, and HCC pathology, the article sets the stage for further exploration of circRNAs as novel investigational theranostic agents in the dynamic realm of HCC.

RUNX1, FUS, and ELAVL1-induced circPTPN22 promote gastric cancer cell proliferation, migration, and invasion through miR-6788-5p/PAK1 axis-mediated autophagy

BACKGROUND

An increasing number of studies have demonstrated the association of circular RNAs (circRNAs) with the pathological processes of various diseases and their involvement in the onset and progression of multiple cancers. Nevertheless, the functional roles and underlying mechanisms of circRNAs in the autophagy regulation of gastric cancer (GC) have not been fully elucidated.

METHODS

We used transmission electron microscopy and the mRFP-GFP-LC3 dual fluorescent autophagy indicator to investigate autophagy regulation. The cell counting kit-8 assay, colony formation assay, 5-ethynyl-2'-deoxyuridine incorporation assay, Transwell assay, and Western blot assay were conducted to confirm circPTPN22's influence on GC progression. Dual luciferase reporter assays validated the binding between circPTPN22 and miR-6788-5p, as well as miR-6788-5p and p21-activated kinase-1 (PAK1). Functional rescue experiments assessed whether circPTPN22 modulates PAK1 expression by competitively binding miR-6788-5p, affecting autophagy and other biological processes in GC cells. We investigated the impact of circPTPN22 on in vivo GC tumors using a nude mouse xenograft model. Bioinformatics tools predicted upstream regulatory transcription factors and binding proteins of circPTPN22, while chromatin immunoprecipitation and ribonucleoprotein immunoprecipitation assays confirmed the binding status.

RESULTS

Upregulation of circPTPN22 in GC has been shown to inhibit autophagy and promote cell proliferation, migration, and invasion. Mechanistically, circPTPN22 directly binds to miR-6788-5p, subsequently regulating the expression of PAK1, which activates protein kinase B (Akt) and extracellular signal-regulated kinase (Erk) phosphorylation. This modulation ultimately affects autophagy levels in GC cells. Additionally, runt-related transcription factor 1 (RUNX1) negatively regulates circPTPN22 expression, while RNA-binding proteins such as FUS (fused in sarcoma) and ELAVL1 (recombinant ELAV-like protein 1) positively regulate its expression. Inhibition of the autophagy pathway can increase FUS expression, further upregulating circPTPN22 in GC cells, thereby exacerbating the progression of GC.

CONCLUSION

Under the regulation of the transcription factor RUNX1 and RNA-binding proteins FUS and ELAVL1, circPTPN22 activates the phosphorylation of Akt and Erk through the miR-6788-5p/PAK1 axis, thereby modulating autophagy in GC cells. Inhibition of autophagy increases FUS, which in turn upregulates circPTPN22, forming a positive feedback loop that ultimately accelerates the progression of GC.

Non-coding RNAs as therapeutic targets in cancer and its clinical application

Cancer genomics has led to the discovery of numerous oncogenes and tumor suppressor genes that play critical roles in cancer development and progression. Oncogenes promote cell growth and proliferation, whereas tumor suppressor genes inhibit cell growth and division. The dysregulation of these genes can lead to the development of cancer. Recent studies have focused on non-coding RNAs (ncRNAs), including circular RNA (circRNA), long non-coding RNA (lncRNA), and microRNA (miRNA), as therapeutic targets for cancer. In this article, we discuss the oncogenes and tumor suppressor genes of ncRNAs associated with different types of cancer and their potential as therapeutic targets. Here, we highlight the mechanisms of action of these genes and their clinical applications in cancer treatment. Understanding the molecular mechanisms underlying cancer development and identifying specific therapeutic targets are essential steps towards the development of effective cancer treatments.

Multi-tissue transcriptome profiling linked the association between tissue-specific circRNAs and the heterosis for feed intake and efficiency in chicken

Heterosis has been widely utilized in chickens. The nonadditive inheritance of genes contributes to this biological phenomenon. However, the role of circRNAs played in the heterosis is poorly determined. In this study, we observed divergent heterosis for residual feed intake (RFI) between 2 crossbreds derived from a reciprocal cross between White Leghorns and Beijing You chickens. Then, circRNA landscape for 120 samples covering the hypothalamus, liver, duodenum mucosa and ovary were profiled to elucidate the regulatory mechanisms of heterosis. We detected that a small proportion of circRNAs (7.83-20.35%) were additively and non-additively expressed, in which non-additivity was a major inheritance of circRNAs in the crossbreds. Tissue-specific expression of circRNAs was prevalent across 4 tissues. Weighted gene co-expression network analysis revealed circRNA-mRNA co-expression modules associated with feed intake and RFI in the hypothalamus and liver, and the co-expressed genes were enriched in oxidative phosphorylation pathway. We further identified 8 nonadditive circRNAs highly correlated with 16 nonadditive genes regulating negative heterosis for RFI in the 2 tissues. Circ-ITSN2 was validated in the liver tissue for its significantly positive correlation with PGPEP1L. Moreover, the bioinformatic analysis indicated that candidate circRNAs might be functioned by binding the microRNAs and interacting with the RNA binding proteins. The integration of multi-tissue transcriptome firstly linked the association between tissue-specific circRNAs and the heterosis for feed intake and efficiency in chicken, which provide novel insights into the molecular mechanism underlying heterosis for feed efficiency. The validated circRNAs can act as potential biomarkers for predicting RFI and its heterosis.

Hallmarks of cancer resistance

This review explores the hallmarks of cancer resistance, including drug efflux mediated by ATP-binding cassette (ABC) transporters, metabolic reprogramming characterized by the Warburg effect, and the dynamic interplay between cancer cells and mitochondria. The role of cancer stem cells (CSCs) in treatment resistance and the regulatory influence of non-coding RNAs, such as long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are studied. The chapter emphasizes future directions, encompassing advancements in immunotherapy, strategies to counter adaptive resistance, integration of artificial intelligence for predictive modeling, and the identification of biomarkers for personalized treatment. The comprehensive exploration of these hallmarks provides a foundation for innovative therapeutic approaches, aiming to navigate the complex landscape of cancer resistance and enhance patient outcomes.

Non-Coding RNAs in Neurological and Neuropsychiatric Disorders: Unraveling the Hidden Players in Disease Pathogenesis

Neurological and neuropsychiatric disorders pose substantial challenges to public health, necessitating a comprehensive understanding of the molecular mechanisms underlying their pathogenesis. In recent years, the focus has shifted toward the intricate world of non-coding RNAs (ncRNAs), a class of RNA molecules that do not encode proteins but play pivotal roles in gene regulation and cellular processes. This review explores the emerging significance of ncRNAs in the context of neurological and neuropsychiatric disorders, shedding light on their diverse functions and regulatory mechanisms. The dysregulation of various ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), has been implicated in the pathophysiology of conditions such as Alzheimer's disease, Parkinson's disease, schizophrenia, and mood disorders. This review delves into the specific roles these ncRNAs play in modulating key cellular processes, including synaptic plasticity, neuroinflammation, and apoptosis, providing a nuanced understanding of their impact on disease progression. Furthermore, it discusses the potential diagnostic and therapeutic implications of targeting ncRNAs in neurological and neuropsychiatric disorders. The identification of specific ncRNA signatures holds promise for the development of novel biomarkers for early disease detection, while the manipulation of ncRNA expression offers innovative therapeutic avenues. Challenges and future directions in the field are also considered, highlighting the need for continued research to unravel the complexities of ncRNA-mediated regulatory networks in the context of neurological and neuropsychiatric disorders. This review aims to provide a comprehensive overview of the current state of knowledge and stimulate further exploration into the fascinating realm of ncRNAs in the brain's intricate landscape.

Unveiling Novel Drug Targets and Emerging Therapies for Rheumatoid Arthritis: A Comprehensive Review

Rheumatoid arthritis (RA) is a chronic debilitating autoimmune disease, that causes joint damage, deformities, and decreased functionality. In addition, RA can also impact organs like the skin, lungs, eyes, and blood vessels. This autoimmune condition arises when the immune system erroneously targets the joint synovial membrane, resulting in synovitis, pannus formation, and cartilage damage. RA treatment is often holistic, integrating medication, physical therapy, and lifestyle modifications. Its main objective is to achieve remission or low disease activity by utilizing a "treat-to-target" approach that optimizes drug usage and dose adjustments based on clinical response and disease activity markers. The primary RA treatment uses disease-modifying antirheumatic drugs (DMARDs) that help to interrupt the inflammatory process. When there is an inadequate response, a combination of biologicals and DMARDs is recommended. Biological therapies target inflammatory pathways and have shown promising results in managing RA symptoms. Close monitoring for adverse effects and disease progression is critical to ensure optimal treatment outcomes. A deeper understanding of the pathways and mechanisms will allow new treatment strategies that minimize adverse effects and maintain quality of life. This review discusses the potential targets that can be used for designing and implementing precision medicine in RA treatment, spotlighting the latest breakthroughs in biologics, JAK inhibitors, IL-6 receptor antagonists, TNF blockers, and disease-modifying noncoding RNAs.

LncRNA-mediated orchestrations of alternative splicing in the landscape of breast cancer

Alternative splicing (AS) is a fundamental post-transcriptional process in eukaryotes, enabling a single gene to generate diverse mRNA transcripts, thereby enhancing protein variability. This process involves the excision of introns and the joining of exons in pre-mRNA(s) to form mature mRNA. The resulting mature mRNAs exhibit various combinations of exons, contributing to functional diversity. Dysregulation of AS can substantially modulate protein functions, impacting the onset and progression of numerous diseases, including cancer. Non-coding RNAs (ncRNAs) are distinct from protein-coding RNAs and consist of short and long types. Long non-coding RNAs (lncRNAs) play an important role in regulating several cellular processes, particularly alternative splicing, according to new research. This review provides insight into the latest discoveries concerning how lncRNAs influence alternative splicing within the realm of breast cancer. Additionally, it explores potential therapeutic strategies focused on targeting lncRNAs.

CircRNAs: Pivotal modulators of TGF-β signalling in cancer pathogenesis

The intricate molecular landscape of cancer pathogenesis continues to captivate researchers worldwide, with Circular RNAs (circRNAs) emerging as pivotal players in the dynamic regulation of biological functions. The study investigates the elusive link between circRNAs and the Transforming Growth Factor-β (TGF-β) signalling pathway, exploring their collective influence on cancer progression and metastasis. Our comprehensive investigation begins by profiling circRNA expression patterns in diverse cancer types, revealing a repertoire of circRNAs intricately linked to the TGF-β pathway. Through integrated bioinformatics analyses and functional experiments, we elucidate the specific circRNA-mRNA interactions that modulate TGF-β signalling, unveiling the regulatory controls governing this crucial pathway. Furthermore, we provide compelling evidence of the impact of circRNA-mediated TGF-β modulation on key cellular processes, including epithelial-mesenchymal transition (EMT), migration, and cell proliferation. In addition to their mechanistic roles, circRNAs have shown promise as diagnostic and prognostic biomarkers, as well as potential molecular targets for cancer therapy. Their ability to modulate critical pathways, such as the TGF-β signalling axis, underscores their significance in cancer biology and clinical applications. The intricate interplay between circRNAs and TGF-β is dissected, uncovering novel regulatory circuits that contribute to the complexity of cancer biology. This review unravels a previously unexplored dimension of carcinogenesis, emphasizing the crucial role of circRNAs in shaping the TGF-β signalling landscape.

M2 macrophage-derived exosomal circTMCO3 acts through miR-515-5p and ITGA8 to enhance malignancy in ovarian cancer

Tumor-associated macrophages of the M2 phenotype promote cancer initiation and progression. Importantly, M2 macrophage-derived exosomes play key roles in the malignancy of cancer cells. Here, we report that circTMCO3 is upregulated in ovarian cancer patients, and its high expression indicates poor survival. M2-derived exosomes promote proliferation, migration, and invasion in ovarian cancer, but these effects are abolished by knockdown of circTMCO3. Furthermore, circTMCO3 functions as a competing endogenous RNA for miR-515-5p to reduce its abundance, thus upregulating ITGA8 in ovarian cancer. miR-515-5p inhibits ovarian cancer malignancy via directly downregulating ITGA8. The decreased oncogenic activity of circTMCO3-silencing exosomes is reversed by miR-515-5p knockdown or ITGA8 overexpression. Exosomal circTMCO3 promotes ovarian cancer progression in nude mice. Thus, M2 macrophage-derived exosomes promote malignancy by delivering circTMCO3 and targeting the miR-515-5p/ITGA8 axis in ovarian cancer. Our findings not only provide mechanistic insights into ovarian cancer progression, but also suggest potential therapeutic targets.

Biophysical characterization of the CXC chemokine receptor 2 ligands

The chemokines of the immune system act as first responders by operating as chemoattractants, directing immune cells to specific locations of inflamed tissues. This promiscuous network is comprised of 50 ligands and 18 receptors where the ligands may interact with the receptors in various oligomeric states i.e., monomers, homodimers, and heterodimers. Chemokine receptors are G-protein coupled receptors (GPCRs) present in the membrane of immune cells. The migration of immune cells occurs in response to a concentration gradient of the ligands. Chemotaxis of neutrophils is directed by CXC-ligand (CXCL) activation of the membrane bound CXC chemokine receptor 2 (CXCR2). CXCR2 plays an important role in human health and is linked to disorders such as autoimmune disorders, inflammation, and cancer. Yet, despite their important role, little is known about the biophysical characteristics controlling ligand:ligand and ligand:receptor interaction essential for biological activity. In this work, we study the homodimers of three of the CXCR2 cognate ligands, CXCL1, CXCL5, and CXCL8. The ligands share high structural integrity but a low sequence identity. We show that the sequence diversity has evolved different binding affinities and stabilities for the CXC-ligands resulting in diverse agonist/antagonist behavior. Furthermore, CXC-ligands fold through a three-state mechanism, populating a folded monomeric state before associating into an active dimer.

Design and Characterization of a New Formulation for the Delivery of COVID-19-mRNA Vaccine to the Nasal Mucosa

Chitosan, a natural polysaccharide derived from chitin, possesses biocompatibility, biodegradability, and mucoadhesive characteristics, making it an attractive material for the delivery of mRNA payloads to the nasal mucosa and promoting their uptake by target cells such as epithelial and immune cells (e.g., dendritic cells and macrophages). In this project, we aimed at developing novel lipid-based nanoformulations for mRNA delivery to counteract the pandemic caused by SARS-CoV-2 virus. The formulations achieved a mRNA encapsulation efficiency of ~80.2% with chitosan-lipid nanoparticles, as measured by the RiboGreen assay. Furthermore, the evaluation of SARS-CoV-2 Spike (S) receptor-binding domain (RBD) expression via ELISA for our vaccine formulations showed transfection levels in human embryonic kidney cells (HEK 293), lung carcinoma cells (A549), and dendritic cells (DC 2.4) equal to 9.9 ± 0.1 ng/mL (174.7 ± 1.1 fold change from untreated cells (UT)), 7.0 ± 0.2 ng/mL (128.1 ± 4.9 fold change from UT), and 0.9 ± 0.0 ng/mL (18.0 ± 0.1 fold change from UT), respectively. Our most promising vaccine formulation was also demonstrated to be amenable to lyophilization with minimal degradation of loaded mRNA, paving the way towards a more accessible and stable vaccine. Preliminary in vivo studies in mice were performed to assess the systemic and local immune responses. Nasal bronchoalveolar lavage fluid (BALF) wash showed that utilizing the optimized formulation resulted in local antibody concentrations and did not trigger any systemic antibody response. However, if further improved and developed, it could potentially contribute to the management of COVID-19 through nasopharyngeal immunization strategies.

Long non-coding RNAs and their role in muscle regeneration

In mammals, most of the genome is transcribed to generate a large and heterogeneous variety of non-protein coding RNAs, that are broadly grouped according to their size. Long noncoding RNAs include a very large and versatile group of molecules. Despite only a minority of them has been functionally characterized, there is emerging evidence indicating long noncoding RNAs as important regulators of expression at multiple levels. Several of them have been shown to be modulated during myogenic differentiation, playing important roles in the regulation of skeletal muscle development, differentiation and homeostasis, and contributing to neuromuscular diseases. In this chapter, we have summarized the current knowledge about long noncoding RNAs in skeletal muscle and discussed specific examples of long noncoding RNAs (lncRNAs and circRNAs) regulating muscle stem cell biology. We have also discussed selected long noncoding RNAs involved in the most common neuromuscular diseases.

Circular RNAs: characteristics, functions, mechanisms, and potential applications in thyroid cancer

Thyroid cancer (TC) is one of the most common endocrine malignancies, and its incidence has increased globally. Despite extensive research, the underlying molecular mechanisms of TC remain partially understood, warranting continued exploration of molecular markers for diagnostic and prognostic applications. Circular RNAs (circRNAs) have recently garnered significant attention owing to their distinct roles in cancers. This review article introduced the classification and biological functions of circRNAs and summarized their potential as diagnostic and prognostic markers in TC. Further, the interplay of circRNAs with PI3K/Akt/mTOR, Wnt/β-catenin, MAPK/ERK, Notch, JAK/STAT, and AMPK pathways is elaborated upon. The article culminates with an examination of circRNA's role in drug resistance of TC and highlights the challenges in circRNA research in TC.

Dysregulated Expression Patterns of Circular RNAs in Cancer: Uncovering Molecular Mechanisms and Biomarker Potential

Circular RNAs (circRNAs) are stable, enclosed, non-coding RNA molecules with dynamic regulatory propensity. Their biogenesis involves a back-splicing process, forming a highly stable and operational RNA molecule. Dysregulated circRNA expression can drive carcinogenic and tumorigenic transformation through the orchestration of epigenetic modifications via extensive RNA and protein-binding domains. These multi-ranged functional capabilities have unveiled extensive identification of previously unknown molecular and cellular patterns of cancer cells. Reliable circRNA expression patterns can aid in early disease detection and provide criteria for genome-specific personalized medicine. Studies described in this review have revealed the novelty of circRNAs and their biological ss as prognostic and diagnostic biomarkers.

CircRNA-regulated glucose metabolism in ovarian cancer: an emerging landscape for therapeutic intervention

Ovarian cancer (OC) has the highest mortality rate among female reproductive system tumours, with limited efficacy of traditional treatments and 5-year survival rates that rarely exceed 40%. Circular RNA (circRNA) is a stable endogenous circular RNA that typically regulates protein expression by binding to downstream miRNA. It has been demonstrated that circRNAs play an important role in the proliferation, migration, and glucose metabolism (such as the Warburg effect) of OC and can regulate the expression of glucose metabolism-related proteins such as GLUT1 and HK2, promoting anaerobic glycolysis of cancer cells, increasing glucose uptake and ATP production, and affecting energy supply and biosynthetic substances to support tumour growth and invasion. This review summarises the formation and characteristics of circRNAs and focuses on their role in regulating glucose metabolism in OC cells and their potential therapeutic value, providing insights for identifying new therapeutic targets.