CIRI: an efficient and unbiased algorithm for de novo circular RNA identification

Integrative and comparative analysis of whole-transcriptome sequencing in circCOL1A1-knockdown and circCOL1A1-overexpressing goat hair follicle stem cells

OBJECTIVE

Hair morphogenesis is tightly related to hair follicle stem cells (HFSCs) proliferation and hair follicle (HF) development. Yangtze River Delta white goats (YRDWG) HFSCs are important for producing superior-quality brush hair (SQBH). Nonetheless, the known regulatory mechanisms are not sufficient to explain YRDWG gHFSCs growth, HF development, and SQBH formation.

METHODS

To deeply investigate the interaction networks and mechanisms of circCOL1A1 in the HF development and SQBH formation of YRDWG in detail, we applied whole-transcriptome sequencing and bioinformatics analysis of circCOL1A1-knockdown and circCOL1A1-overexpressing HFSCs from YRDWG. STRING and other databases were used to construct multiple interaction networks. Differentially expressed (DE) genes, DE-miRNAs, and DE-circRNAs were further confirmed via real-time quantitative polymerase chain reaction and Sanger sequencing.

RESULTS

A total of 87 genes, 96 miRNAs, and 135 circRNAs were DE between circCOL1A1-knockdown and circCOL1A1-overexpressing gHFSCs. Functional enrichment, gene ontology annotation and Kyoto encyclopedia of genes and genomes analyses identified marked enrichment of these DE- genes, DE-miRNAs, and DE-circRNAs in the MAPK, PI3K/Akt, and focal adhesion signaling pathways, which are closely associated with gHFSCs growth and HF development. In addition, through interaction network construction, four important regulatory axes were obtained, namely, the chi-circCOL1A1-miR-149-5p-CMTM3-AR, chi-circACTN1- miR-671-5p-MAPK3/COL13A1, chi-circITGA6-miR-18a-5p-FGF1/MAP3K1 and chi-circ COBLL1-miR-30a-5p/miR-128-3p-ITGA6/MAPK14/FGF14 axes.

CONCLUSION

These novel findings provide a valuable and comprehensive basis for investigating the complex mechanism by which circRNAs participate in and regulate HF development and SQBH formation in YRDWG.

Identification of biomarkers of male infertility through the circRNA expression profiling of seminal plasma

Circular RNAs (circRNAs) are key regulators of reproductive biology. However, limited information is available regarding circRNA expression profiles in seminal plasma samples from individuals with male infertility. The present study aimed to identify circRNAs associated with infertility in seminal plasma samples and to clarify their potential as biomarkers, as well as the possible molecular mechanisms underlying their functions. Next-generation RNA sequencing was conducted to analyze circRNA profiles in seminal plasma from healthy controls, oligoasthenospermia (OAZ) patients, and non-obstructive azoospermia (NOA) patients. Bioinformatics analysis revealed that 637 circRNAs were differentially expressed between OAZ and control subjects, as well as 272 circRNAs that were differentially expressed between NOA and control subjects. The expression of key circRNAs ( hsa-SAP130_0002, hsa-TRPC1_0001, hsa-FBRS_0001, hsa-ACACA_0025, hsa-UTRN_0042, and hsa-ZNF532_0023) was then validated by qPCR, and their diagnostic accuracy for infertility was confirmed through ROC curve analysis. Additionally, possible circRNA-miRNA-mRNA regulatory networks were developed for these candidate biomarkers. Collectively, this study identifies a novel set of circRNAs with potential as diagnostic biomarkers for male infertility and provides molecular insights that may facilitate both diagnostic and therapeutic efforts.

Circ 0020938 inhibits hair follicle stem cells proliferation via the miR-142-5p/DSG4 axis in cashmere goats

BACKGROUND

Shaanbei white cashmere goat is an excellent cashmere goat breed, and its market favored cashmere from the secondary hair follicles. Hair follicles mature around birth and each hair follicle repeatedly undergoes a growth cycle that comprises three distinct stages: anagen, catagen and telogen. Understanding the molecular mechanisms controlling cyclic hair follicle changes is essential for optimizing hair follicle function and improving cashmere production.

METHODS

The circRNA expression profile in the hair follicle cycle was constructed and differentially expressed circRNAs were identified, with particular focus on circ 0020938, which was highly expressed during anagen. The functional assays were performed to assess the effect of circ 0020938 on hair follicle stem cells (HFSCs) proliferation. Competing endogenous RNA (ceRNA) network was constructed to investigate the interaction between circ 0020938, miR-142-5p, and DSG4. Rescue experiment was conducted to validate the impact of circ 0020938 on HFSCs proliferation and DSG4 expression.

RESULTS

We found that circ 0020938 inhibited HFSCs proliferation. Further analysis revealed that circ 0020938 acted as a sponge for miR-142-5p, alleviating the repression of DSG4. Additionally, we confirmed that DSG4 inhibited HFSCs proliferation, suggesting that it play a key role in regulating the balance between proliferation and differentiation during the hair follicle cycle. Rescue experiments showed that the inhibition of HFSCs proliferation by circ 0020938 was partially reversed by miR-142-5p.

CONCLUSION

Our study provides novel insights into the regulatory role of circRNA in HFSCs proliferation during the hair follicle cycle. The results demonstrate that circ 0020938 acts as a miRNA sponge and inhibits HFSCs proliferation through the miR-142-5p/DSG4 axis, thereby contributing to the proper progression of the hair follicle cycle.

Bioinformatics analysis of circular RNAs associated with atrial fibrillation and their evaluation as predictive biomarkers

BACKGROUND

Circular noncoding RNAs (circRNAs) are implicated in many human diseases, but their role in atrial fibrillation (AF) is poorly understood. In this study, we performed bioinformatics analysis of circRNA sequencing data to identify AF-related circRNAs.

METHODS

Left atrial appendage (LAA) samples were obtained from patients with valvular heart disease and were categorised into the sinus rhythm (SR; n = 4) and AF (n = 4) groups. CircRNA sequencing analysis was performed to identify differentially expressed (DE) circRNAs in AF patients. Functional enrichment analysis of DE circRNAs was performed to identify enriched Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways.

RESULTS

We identified 3338 DE circRNAs, including 2147 upregulated and 1191 downregulated circRNAs, in AF patients. A ceRNA network of 16 DE circRNAs, 11 DE miRNAs, and 15 DE mRNAs was constructed. Functional enrichment analyses revealed that the AF-related DE circRNAs were enriched in response to vitamin D, the potassium channel complex, delayed rectifier potassium channel activity, osteoclast differentiation, primary immunodeficiency, endocrine and other factor-regulated calcium reabsorption and other processes. ROC curve analysis identified circRNA_00324, circRNA_17225, circRNA_16305, circRNA_10233, circRNA_05499, circRNA_03183, circRNA_14211, and circRNA_18422 as potential predictive biomarkers for distinguishing AF patients from SR patients, with AUC values of 0.9138, 0.7370, 0.8526, 0.6803, 0.8163, 0.8662, 0.7664, and 0.9320, respectively.

CONCLUSIONS

In this study, we constructed an AF-related ceRNA network and identified eight circRNAs as potential predictive biomarkers of AF.

Comprehensive Analysis of circRNA Expression and circRNA-miRNA-mRNA Networks in the Ventral Hippocampus of the Rat: Impact of Chronic Stress and Biological Sex

This study provides new insights into how sex and chronic stress influence circRNA expression in the rat ventral hippocampus, a region critical for emotional processing. We identified 206 sex-biased circRNAs and 194 stress-responsive circRNAs, highlighting distinct expression profiles. Parental genes of male circRNAs were primarily enriched in synaptic transmission pathways, while those of female circRNAs were associated with axon guidance, emphasizing sex-specific molecular differences. Chronic stress also triggered miRNA changes unique to each sex, revealing divergent regulatory mechanisms. The identified circRNA-miRNA-mRNA axes, modulated under stress, appear to regulate the translation of numerous potential mRNA targets. In males, stress positively regulated neuroprotective pathways, suggesting a compensatory response to mitigate stress-induced damage. In contrast, females exhibited a broader translational network that favored mRNA expression without distinct pathway-specific actions. However, the smaller repressed network in females─characterized by a higher circRNA-to-miRNA and mRNA ratio─may indicate a more selective and targeted regulatory mechanism, with many interactions linked to anti-inflammatory processes. Coexpression analysis revealed two male-specific modules with altered activity under stress. These were associated with processes such as reticulum stress and actin dynamics, the latter linked to dendritic spine loss and depressive-like behaviors, extensively documented in chronically stressed male rats. Conversely, females displayed an activated stress-responsive module, promoting axon guidance and long-term potentiation, which may contribute to improved cognitive outcomes. Among the identified circRNAs, rno-Gabrg3_0001 emerged as stress-sensitive in males. This circRNA exhibited predicted miRNA binding sites and interactions with proteins involved in vesicle trafficking, forming part of a highly active module enriched in genes related to ion transport and membrane protein localization. Overall, these findings uncover sex-dependent regulatory mechanisms driving transcriptomic changes under chronic stress, deepening our understanding of ventral hippocampal molecular functions. Investigating these regulatory networks, which differentially affect the male and female ventral hippocampus, could inform the development of sex-specific therapeutic strategies for stress-related disorders.

The biomarker potential of circPOLD1 and its binding protein YBX1 in cervical carcinogenesis

BACKGROUND

Cervical cancer progresses through distinct precancerous stages, making early screening and intervention crucial for prevention. However, conventional screening modalities, such as cytology and HPV testing, face challenges related to sensitivity, specificity, and resource dependency. Circular RNAs (circRNAs), owing to their high stability and tissue-specific expression, have emerged as promising biomarkers, though their role in cervical carcinogenesis remains underexplored. In particular, the clinical utility of circRNAs for optimizing cervical cancer screening and early diagnosis has yet to be established. This study aimed to investigate the dynamic expression profiles of circRNAs across various stages of cervical cancer progression and identify potential biomarkers to enhance early detection.

METHODS

CircRNA sequencing was performed on cervical tissues spanning normal cervical epithelium (NCE), high-grade squamous intraepithelial lesions (HSIL), and cervical squamous cell carcinoma (CSCC). Functional assays, including cell viability, colony formation, and apoptosis, were performed to assess the oncogenic potential of circPOLD1 and its interaction with YBX1 in cervical cancer cells. BaseScope and immunohistochemistry (IHC) were applied to tissue microarrays for clincial validation and ROC curve analysis evaluated the diagnostic performance of circPOLD1 in serum as a liquid biopsy marker.

RESULTS

CircRNA profiling revealed a progressive increase in circPOLD1 expression from NCE to HSIL and CSCC. Mechanistically, circPOLD1 functioned as an oncogene by binding to and phosphorylating YBX1, activating the AKT/mTOR/HIF-1α pathway to enhance glycolysis-driven tumorigenesis. BaseScope and IHC confirmed the stage-specific elevation of circPOLD1 and YBX1 in cervical lesions. The circPOLD1/YBX1 multi-marker panel demonstrated superior diagnostic performance, achieving an AUC of 0.951 for LSIL+ and 0.817 for HSIL+ detection. Furthermore, serum circPOLD1 levels exhibited a progressive increase across disease stages, underscoring its potential as a non-invasive biomarker.

CONCLUSION

circPOLD1 and YBX1 synergistically drive cervical carcinogenesis and exhibit stage-specific expression patterns. Their combined detection significantly enhanced the accuracy for cervical cancer screening and dynamic monitoring. The successful application of BaseScope and IHC highlights the immediate translational potential of these biomarkers, paving the way for refined risk stratification, improved therapeutic targeting, and reduced cervical cancer burden through early intervention.

Circular RNA transcriptome across various development periods of Paralichthys olivaceus reveal skeletal muscle-specific circchd6 regulating myogenesis

The Japanese flounder (Paralichthys olivaceus) is greatly influenced in terms of muscle quality and quantity by the development of skeletal muscle. While the mechanisms underlying skeletal muscle development are well-studied, the role of non-coding RNAs, particularly circRNAs, in the skeletal muscle development of Japanese flounder remains unclear. To investigate the expression patterns of circRNAs during different developmental stages (JP1: 7 days, JP2: 90 days, JP3: 24 months (female), JP4: 24 months (male)) in Japanese flounder, we performed transcriptome sequencing analysis. We identified a total of 3523 circRNAs, of which 10.19 % were differentially expressed. These differentially expressed (DE) circRNAs were studied, and their impacts on muscle development were analyzed. The RNA interaction network revealed that skeletal muscle-specific circchd6 targeted novel-miR-508 and further regulated dual specificity tyrosine-phosphorylation regulated kinase 2 (dyrk2). Functional analysis showed that overexpressed circchd6 and dyrk2 promoted myoblast proliferation and differentiation, while novel-miR-508 inhibited both. Our study identified the circchd6-novel-miR-508-dyrk2 axis as a regulatory mechanism and provided new evidence for the use of epigenetic approaches in genetic breeding.

Oncolytic virus VG161 in refractory hepatocellular carcinoma

Hepatocellular carcinoma remains a life-threatening malignancy with limited therapeutic options following the failure of second-line treatments1,2. Oncolytic viruses selectively replicate in and lyse cancer cells, releasing neoantigens and stimulating systemic antitumour immunity3, offering a potential therapeutic option. Here we present the results of a multicentre phase 1 clinical trial evaluating VG161, an engineered oncolytic herpes simplex virus that expresses IL-12, IL-15, IL-15Rα and a PD-1-PD-L1-blocking fusion protein4, for safety and efficacy in patients with advanced liver cancer. VG161 was well tolerated, with no dose-limiting toxicities observed, and it demonstrated promising efficacy by reshaping the tumour immune microenvironment and re-sensitizing tumours that were previously resistant to systemic treatments. Notably, we also found that patients who had previously been sensitive to checkpoint inhibitor therapy showed enhanced efficacy with VG161 treatment. Furthermore, we developed an efficacy-prediction model based on differentially expressed genes, which successfully identified patients who were likely to benefit from VG161 and predicted prolonged overall survival. These findings position VG161 as a promising third-line therapeutic option for refractory hepatocellular carcinoma. This provides a new avenue for treatment and advances the field of oncolytic virus-based immunotherapies. ClinicalTrials.gov registration: NCT04806464 .

The emerging functions and clinical implications of circRNAs in acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a prevalent haematologic malignancy characterized by significant heterogeneity. Despite the application of aggressive therapeutic approaches, AML remains associated with poor prognosis. Circular RNAs (circRNAs) constitute a unique class of single-stranded RNAs featuring covalently closed loop structures that are ubiquitous across species. These molecules perform crucial regulatory functions in the pathogenesis of various diseases through diverse mechanisms, including acting as miRNA sponges, interacting with DNA or proteins, and encoding functional proteins/polypeptides. Recently, numerous circRNAs have been confirmed to have aberrant expression patterns in AML patients. In particular, certain circRNAs are closely associated with specific clinicopathological characteristics and thus have great potential as diagnostic/prognostic biomarkers and therapeutic targets in AML. Herein, we systematically summarize the biogenesis, degradation, and functional mechanisms of circRNAs while highlighting their clinical relevance. We also outline a series of online databases and analytical tools available to facilitate circRNA research. Finally, we discuss the current challenges and future research priorities in this evolving field.

Long Circulating RNAs Packaged in Extracellular Vesicles: Prospects for Improved Risk Assessment in Childhood B-Cell Acute Lymphoblastic Leukemia

Analysis of tumoral RNA from bone marrow (BM) biopsy is essential for diagnosing childhood B-cell acute lymphoblastic leukemia (B-ALL), risk stratification, and monitoring, by detecting fusions and gene expression patterns. However, frequent BM biopsies are invasive and traumatic for patients. Small extracellular vesicles (sEVs) circulating in blood contain a variety of biomolecules, including RNA, that may contribute to cancer progression, offering a promising source of non-invasive biomarkers from liquid biopsies. While most EV studies have focused on small RNAs like microRNAs (miRNAs), the role of longer RNA species, including messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), remains underexplored despite their demonstrated potential for risk-based patient stratification when starting from BM biopsies. We used immuno-purification to isolate sEVs from peripheral blood at diagnosis in B-ALL patients and cell model-based conditioned culture medium (CCM) with ETV6::RUNX1 and TCF3::PBX1 fusions. Using whole-transcriptome sequencing targeting transcripts over 200 nt and a novel data analysis pipeline, we identified 102 RNA transcripts (67 mRNAs, 16 lncRNAs, 10 circRNAs, 4 pseudogenes, and 5 others) in patient-derived sEVs. These transcripts could serve as biomarkers for two distinct molecular subgroups of B-ALL, each with different risk profiles at diagnosis. This is the first study characterizing the long transcriptome in blood-derived sEVs for childhood B-ALL, highlighting the potential use of circulating RNAs for improved risk-based stratification.

Genome wide analysis of allele-specific circular RNAs in mammals and their role in cell proliferation

Circular RNAs (circRNAs) are a large class of widely expressed RNAs with covalently closed continuous structures. However, it is currently unknown if circRNAs shows allele-specific expression, as are the consequences of genetic variation on their circularization efficiency and subsequent biological function. Here, we propose a novel pipeline, ASE-circRNA, to accurately quantify both circRNA and their related linear RNA for each allele, and then assess the allele-specificity of the expression of a circular RNA. We identified and analyzed allele-specific circRNAs from human tissue, as well as brains from reciprocal crosses between pairs of highly divergent strains of both mice and pigs by next generation sequencing. Droplet digital PCR (ddPCR) was used to confirm the circularization efficiency measured by next generation sequencing. We found that variation in intron sequences affect the circularization efficiency of circRNAs. Furthermore, we demonstrate that a circRNA, circHK1, regulates the expression of POLR2A to influence the rate of cell proliferation. Our study provides new insight into the molecular mechanisms impacted by variation in genome sequence in the origin of human disease and phenotype.

Identification of circular RNAs as biomarkers for pupal age estimation and postmortem interval in forensically important Sarcophaga peregrina (Diptera: Sarcophagidae)

Accurate estimation of the pupal age in necrophagous flies is vital for determining the postmortem interval (PMI) in forensic entomology. Differential expression of genes (DEGs) exhibits temporal fluctuations across the developmental stages of these flies. This study evaluates circular RNAs (circRNAs) as novel molecular markers and develops a model for predicting pupal development time based on circRNA expression. Transcriptomic analysis of Sarcophaga peregrina pupae at various stages identified four circRNAs (circRNA_0037, circRNA_0531, circRNA_3373, circRNA_2847) showing significant expression differences. Using real-time quantitative PCR and regression analysis, we constructed a model to estimate development time, which accurately predicts intra-puparial periods. Additionally, we examined circRNA degradation patterns in pupae under lethal conditions and identified a clear degradation trend in circRNA_2847, suggesting its potential use for estimating the PMI. This study introduces new molecular markers and insights for estimating necrophagous fly pupal age.

Noncanonical circRNA biogenesis driven by alpha and gamma herpesviruses

Herpesviruses require the host transcriptional machinery, inducing significant changes in gene expression to prioritize viral transcripts. We examined alpha- and gamma-herpesvirus alterations to a type of alternative splicing, namely circular RNA (circRNA) synthesis. We developed "Circrnas in Host And viRuses anaLysis pIpEline" (CHARLIE) to facilitate viral profiling. This method identified thousands of back-splicing variants, including circRNA common to lytic and latent phases of infection. Ours is the first report of Herpes Simplex Virus-1 circRNAs, including species derived from ICP0 and the latency-associated transcript. We characterized back-splicing cis- and trans-elements, and found viral circRNAs resistant to spliceosome perturbation and lacking canonical splice donor-acceptors. Subsequent loss-of-function studies of host RNA ligases (RTCB, RLIG1) revealed instances of decreased viral back splicing. Using eCLIP and 4sU-Sequencing, we determined that the KSHV RNA-binding protein, ORF57, enhanced synthesis for a subset of viral and host circRNAs. Our work explores unique splicing mechanisms driven by lytic infection, and identifies a class of transcripts with the potential to function in replication, persistence, or tumorigenesis.

circ2LO: Identification of CircRNA Based on the LucaOne Large Model

Circular RNA is a type of noncoding RNA with a special covalent bond structure. As an endogenous RNA in animals and plants, it is formed through RNA splicing. The 5' and 3' ends of the exons form circular RNA at the back-splicing sites. Circular RNA plays an important regulatory role in diseases by interacting with the associated miRNAs. Accurate identification of circular RNA can enrich the data on circular RNA and provide new ideas for drug development. At present, mainstream circular RNA recognition algorithms are divided into two categories: those based on RNA sequence position information and those based on RNA sequence biometric information. Herein, we propose a method for the recognition of circular RNA, called circ2LO, which utilizes the LucaOne large model for feature embedding of the splicing sites of RNA sequences as well as their upstream and downstream sequences to prevent semantic information loss caused by the traditional one-hot encoding method. Subsequently, it employs a convolutional layer to extract features and a self-attention mechanism to extract interactive features to accurately capture the core features of the circular RNA at the splicing sites. Finally, it uses a fully connected layer to identify circular RNA. The accuracy of circ2LO on the human dataset reached 95.47%, which is higher than the values shown by existing methods. It also achieved accuracies of 97.04% and 72.04% on the Arabidopsis and mouse datasets, respectively, demonstrating good robustness. Through rigorous validation, the circ2LO model has proven its high-precision identification capability for circular RNAs, marking it as a potentially transformative analytical platform in the circRNA research field.

Circular RNAs in cancer stem cells: Insights into their roles and mechanisms (Review)

Cancer stem cells (CSCs) represent a small, yet pivotal subpopulation of tumor cells that play significant roles in tumor initiation, progression and therapeutic resistance. Circular RNAs (circRNAs) are a distinct class of RNAs characterized by their closed‑loop structures, lacking 5' to 3'ends. There is growing evidence that circRNAs are integral to the development and regulation of CSCs. Aberrant expression of circRNAs in CSCs can contribute to oncogenic properties and drug resistance. Specifically, oncogenic circRNAs modulate CSC behavior via key signaling pathways, thereby promoting CSC self‑renewal and maintenance, as well as tumor progression. This review summarizes the latest research on the functional roles and regulatory mechanisms of circRNAs in CSC behavior and discusses potential applications and challenges of targeting circRNAs in CSCs. Understanding the intricate interactions between circRNAs and CSCs may lead to novel therapeutic strategies that effectively combat treatment resistance and improve patient outcomes.

Identification of the crucial circ-mi-mRNA interaction networks regulating testicular development and spermatogenesis in ganders

Semen quality has an important impact on the reproductive performance of ganders, and the quantity and quality of spermatozoa in semen are the determinants of semen quality. In our practical work, a small number of azoospermic ganders were observed in adult goose breeding populations, but the underlying regulatory mechanisms remain unknown. In the present study, we firstly compared the morphological and histological differences in the testes of ganders from normozoospermic group (NG) and azoospermic group (AG), and then analyzed the testicular expression patterns of circRNAs, miRNAs, and mRNAs between the two groups by using whole-transcriptome sequencing technology. Results from histomorphological analysis demonstrated that the body weight alone was not accountable for the occurrence of gander azoospermia, and the possible cause might be the observed testicular abnormalities. At the morphological level, the left, right, and bilateral testicular weights, the right and bilateral testicular organ indexes, and the long, short, and dorsoventral diameters of the left, right and bilateral testes were significantly lower in AG than in NG (P < 0.05). At the histological level, most testicular histological parameters, such as the testicular parenchymal area, the diameter of seminiferous tubules, and the number of germ cells, were significantly higher (P < 0.05) in NG than in AG. The RNA-seq results showed that a total of 683 differentially expressed circRNAs (DEcircRNAs), 24 differentially expressed miRNAs (DEmiRNAs), and 1,118 differentially expressed Genes (DEGs) were identified in the gander testes between NG and AG. Subsequent functional enrichment analysis revealed that most of the DEGs and the target genes of DEcircRNAs and DEmiRNAs were significantly enriched in either the biological processes related to male gonad development, spermatid development, and regulation of cell differentiation or the KEGG terms including the MAPK, TGF-beta, Wnt, and cell cycle signaling pathways. By constructing the core ceRNA regulatory networks, several key DEcircRNAs, including 1:98100313|98104995, 1:171413706|171419341, 6:3414226|3418193, and 2:115876735|115880760, were identified to regulate the expression of TGFB2 and BCL2 through interactions with specific miRNAs such as novel-miR-265 and novel-miR-266, and such interactions could play crucial roles in regulating the gander testicular cell apoptosis, proliferation, and spermatogenesis. This study provides novel insights into the function and molecular mechanisms of ceRNAs in regulating the gander testicular development and semen quality.

Transcriptomic analysis of two Chinese wheat landraces with contrasting Fusarium head blight resistance reveals miRNA-mediated defense mechanisms

Introduction

Fusarium head blight (FHB), caused primarily by Fusarium graminearum (Fg), poses a significant threat to wheat production. It is necessary to deeply understand the molecular mechanisms underlying FHB resistance in wheat breeding.

Methods

In this study, the transcriptomic responses of two Chinese wheat landraces-Wuyangmai (WY, resistant) and Chinese Spring (CS, susceptible)-to F. graminearum infection were examined using RNA sequencing (RNA-seq). Differential expression of mRNAs, long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs) was analyzed at 3 and 5 days post-Fg inoculation (dpi).

Results

The results showed that WY exhibited a targeted miRNA response, primarily modulating defense-related pathways such as glutathione metabolism and phenylpropanoid biosynthesis, which are crucial for oxidative stress regulation and pathogen defense response. In contrast, CS displayed a broader transcriptional response, largely linked to general metabolic processes rather than immune activation. Notably, the up-regulation of genes involved in oxidative stress and immune defense in WY confirmed its enhanced resistance to FHB. The integrated analysis of miRNA-mRNA interactions highlighted miRNAs as central regulators of defense mechanisms in WY, particularly at later stages of infection. These miRNAs targeted genes involved in immune responses, while lncRNAs and circRNAs played a more limited role in the regulation of defense responses. The GO and KEGG pathway enrichment analyses further revealed that WY enriched for plant-pathogen interaction and secondary metabolite biosynthesis pathways, which are crucial for pathogen resistance. In contrast, CS prioritized metabolic homeostasis, suggesting a less effective defense strategy.

Discussion

Overall, this study underscores the critical role of miRNA-mediated regulation in FHB resistance in WY. These insights into miRNA-mediated regulatory mechanisms provide a molecular basis for breeding FHB-resistant wheat varieties and highlight miRNA-mRNA interactions as promising targets for enhancing disease resilience.

Viral circular RNA-encoded protein, ceVP28, divulges an antiviral response in invertebrates

Invertebrates mostly use innate immunity to counteract pathogenic infections. In this study, shrimp was used as a model organism to explore the functions of circular RNAs (circRNAs) derived from white spot syndrome virus (WSSV). We identified four viral circRNAs, termed circWSSV147, circWSSV326, circWSSV458, and circVP28, from transcriptomic data of WSSV-infected shrimp. CircVP28, which contains an internal ribosome entry site, was further characterized to determine its potential as a template for protein translation. We observed the presence of a truncated, circRNA-encoded VP28 (ceVP28) in infected shrimp. Both ceVP28 and its parental counterpart, VP28, share the same host cell binding partner Rab7, which is a host receptor for WSSV. Coadministration of recombinant ceVP28 protein and WSSV to penaeid shrimps reduced both viral copy numbers and mortality upon WSSV challenges. These findings uncovered a host defense mechanism by which a protein encoded by a viral circRNA modulates virus-receptor interactions, resulting in blocking of viral entry.

CircRNA-mediated ceRNA regulatory networks: transcriptomic insights into obesity type 2 diabetes progression and treatment strategies

The aim of this study was to deeply explore the pathogenesis of obesity type 2 diabetes mellitus (O-T2DM) and search for potential biomarkers through high-throughput RNA sequencing technology. The study included 15 patients with O-T2DM and 15 healthy controls, and peripheral blood samples were collected for transcriptome analysis. The results showed that compared with the control group, there were 442 circRNAs and 2756 mRNAs with significant differential expression in the O-T2DM group. Through weighted gene co-expression network analysis (WGCNA) and pathway enrichment analysis, it was found that the differentially expressed mRNAs were mainly enriched in signaling pathways such as T cell receptor, cell senescence, cytotoxicity mediated by NK cells, IL-17, lipids and atherosclerosis, and the oxidative phosphorylation pathway was activated, and apoptosis was inhibited. Based on the ceRNA theory, a regulatory network was constructed, and key circRNAs such as hsa_circ_0060614 were screened out, which may regulate the expression of the MT2A gene by adsorbing hsa-mir-4668-3p, and the expression levels of the three were significantly increased in O-T2DM patients. This study provides a new perspective for the research on the molecular mechanism of O-T2DM and an important theoretical basis for the development of personalized treatment and precision medicine for it.

Past, present, and future strategies for detecting and quantifying circular RNA variants

Circular RNAs (circRNAs) are a family of covalently closed RNA transcripts ubiquitous across the eukaryotic kingdom. CircRNAs are generated by a class of alternative splicing called backsplicing, with the resultant circularization of a part of parental RNA producing the characteristic backsplice junction (BSJ). Because of the noncontiguous sequence of the BSJ with respect to the DNA genome, circRNAs remained hidden in plain sight through over a decade of RNA next-generation sequencing, yet over 3 million unique circRNA transcripts have been illuminated in the past decade alone. CircRNAs are expressed in a cell type-specific manner, are highly stable, with many examples of circRNAs being evolutionarily conserved and/or functional in specific contexts. However, circRNAs can be very lowly expressed and predictions of the circRNA context from BSJ-spanning reads alone can confound extrapolation of the exact sequence composition of the circRNA transcript. For these reasons, specific and ultrasensitive detection, combined with enrichment, bespoke bioinformatics pipelines and, more recently, long-read, highly processive sequencing is becoming critical for complete characterization of all circRNA variants. Concomitantly, the need for targeted detection and quantification of specific circRNAs has sparked numerous laboratory-based and commercial approaches to visualize circRNAs in cells and quantify them in biological samples, including biospecimens. This review focuses on advancements in the detection and quantification of circRNAs, with a particular focus on recent next-generation sequencing approaches to bolster detection of circRNA variants and accurately normalize between sequencing libraries.

Bioinformatics screening and clinical validation of CircRNA and related miRNA in male osteoporosis

BACKGROUND

The pathogenesis of male osteoporosis (MOP) remains unclear, with the role of genetic factors attracting the attention of researchers. In the present study, we aimed to investigate critical circRNA biomarkers associated with male osteoporosis.

METHODS

RNA-sequencing was performed to investigate the circRNA expression profiles between 3 men with osteoporosis and 3 with normal mass density. Then, shared mRNAs between host genes acquired in this present study and mRNAs acquired in previous study were identified to screen vital circRNAs associated with male osteoporosis. PPI networks of shared mRNAs were constructed and the hub genes in the PPI networks were identified with CytoHubba, a plugin in Cytoscape software (3.10.1). Finally, a ceRNA network of four circRNAs derived from three hub genes was constructed. Validation experiments were performed on selected circRNAs and related miRNAs in this ceRNA network using peripheral blood clinical samples.

RESULTS

In total, 657 circRNAs were detected in male osteoporosis. The shared mRNAs were significantly enriched in the metabolic pathways, RNA transport, Ubiquitin mediated proteolysis and Amyotrophic lateral sclerosis. Then, three genes, including SETD2, ATM and XPO1, were identified as hub genes with four algorithms. Ultimately, the ceRNA network, involving 4 circRNAs, 40 miRNAs, and 592 mRNAs, was obtained. Using 35 clinical samples, three potential circRNAs and three miRNAs associated with male osteoporosis were selected for validation. It was ultimately found that three miRNAs were upregulated in MOP, while hsa-circ-9130, novel_circ_0014940 and hsa-circ-0054894 were upregulated, hsa-circ-2484 and novel_circ_0033084 were downregulated in patients with MOP.

CONCLUSION

We emphasized the roles of several significantly up- and down-regulated circRNAs and four circRNAs derived from three hub genes in male osteoporosis. Differences in expression were confirmed for three miRNAs and five circRNAs in the ceRNA network among patients with male osteoporosis.

Enhanced Oxidative Phosphorylation Driven by TACO1 Mitochondrial Translocation Promotes Stemness and Cisplatin Resistance in Bladder Cancer

Chemoresistance poses a critical obstacle in bladder cancer (BCa) treatment, and effective interventions are currently limited. Elevated oxidative phosphorylation (OXPHOS) has been linked to cancer stemness, a determinant of chemoresistance. However, the mechanisms underlying increased OXPHOS during cancer cell chemoresistance remain unclear. This study revealed that the mitochondrial translational activator of cytochrome oxidase subunit 1 (TACO1) is linked to stemness and cisplatin resistance in BCa cells. Mechanistically, mitochondrial TACO1 enhances the translation of the mitochondrial cytochrome c oxidase I (MTCO1), promoting mitochondrial reactive oxygen species (mtROS) by upregulating OXPHOS, consequently driving cancer stemness and cisplatin resistance. Intriguingly, the mitochondrial translocation of TACO1 is mediated by the heat shock protein 90 β (HSP90β), a process that requires circFOXK2 as a scaffold for the TACO1-HSP90β interaction. The mutations at the binding sites of TACO1-circFOXK2-HSP90β disturb the ternary complex and inhibit cancer stemness and cisplatin resistance in BCa cells by suppressing the MTCO1/OXPHOS/mtROS axis. Clinically, BCa patients with increased mitochondrial TACO1 expression respond poorly to cisplatin treatment. This study elucidates the mechanisms by which TACO1 promotes BCa stemness and cisplatin resistance, providing a potential target for mitigating cisplatin resistance for BCa and a biomarker for predicting cisplatin response.

circICMT upregulates and suppresses the malignant behavior of bladder cancer

BACKGROUND

Circular RNA (circRNA) is a new type of endogenous single-stranded RNA with a covalently closed circular structure. Increasing evidence shows that circRNA plays an important role in regulating gene expression in tumors. circICMT is a circular RNA produced by the ICMT gene. Currently, the molecular function of circICMT in bladder cancer remains unclear.

METHOD

Differentially expressed circRNAs were identified from RNA sequencing data and circICMT was identified as a new candidate circRNA. qRT-PCR and sanger sequencing were used to detect the expression of circICMT in bladder cancer tissue specimens. Stable cell lines overexpressing and knocking down circICMT were constructed to explore the effect of circICMT on bladder cancer cells. Its biological effects were detected through wound healing experiments, colony formation experiments, CCK-8 experiments and xenogeneic tumorigenesis experiments.

RESULT

This study found that circICMT was significantly upregulated in bladder cancer tissue specimens. Overexpression of circICMT can inhibit cell migration, proliferation and colony formation ability, while knockdown of circICMT promotes the malignant phenotype of bladder cancer cells. Bioinformatics predictions have found that circICMT can bind to a variety of miRNAs and RBPs and may form a complex regulatory network to regulate the progression of bladder cancer.

CONCLUSION

circICMT is significantly highly expressed in bladder cancer, and intervening circICMT expression affects the malignant phenotype of bladder cancer cells in vivo and in vitro, which may provide potential biomarkers and therapeutic targets for the management of bladder cancer.

Whole-transcriptome analysis reveals the profiles and roles of coding and non-coding RNAs during hair follicle cycling in Rex rabbits

BACKGROUND

Rex rabbit is famous for its silky and soft fur coat, a characteristic predominantly attributed to its hair follicles. Numerous studies have confirmed the crucial roles of mRNAs and non-coding RNAs (ncRNAs) in regulating key cellular processes such as cell proliferation, differentiation, apoptosis and immunity. However, their involvement in the regulation of the hair cycle in Rex rabbits remains unknown.

RESULTS

In this study, we identified the hair follicle stages of Rex rabbits aged 3 to 5.5 months. Skin samples collected at 4, 5 and 5.5 months, representing the morphological features of the anagen, catagen and telogen stage separately, were finally selected for whole-transcriptome analysis. 25,736 mRNA, 8280 lncRNA, 24,885 circRNA and 1138 miRNA transcripts were identified. 6027 differently expressed mRNAs (DEGs), 2381 differently expressed lncRNAs (DELs), 438 differently expressed circRNAs (DECs) and 167 differently expressed miRNAs (DEMs) were detected in the anagen vs. catagen (AvC) comparison. 4092 DEGs, 1540 DELs, 356 DECs and 141 DEMs were detected in the anagen vs. telogen (AvT) comparison. 2290 DEGs, 779 DELs, 249 DECs and 92 DEMs were detected in the catagen vs. telogen (CvT) comparison. DEGs were primarily enriched in GO items including plasma membrane, integral component of plasma membrane and extracellular space. KEGG enrichment analysis revealed that DEGs were mainly enriched in PI3K-Akt signaling pathway, cell cycle and Wnt signaling pathway (p < 0.05). KEGG analysis showed trans-acting genes of DELs were significantly enriched in Hippo signaling pathway, PI3K-Akt signaling pathway and Melanogenesis. Target genes of DEMs were mainly enriched in MAPK signaling pathway, Wnt signaling pathway, ECM-receptor interaction and Signaling pathways regulating pluripotency of stem cells. Based on the ceRNA mechanism, lncRNA/circRNA-miRNA-mRNA networks were constructed involving 9 DECs, 437 DELs, 50 DEMs and 416 DEGs.

CONCLUSIONS

Totally, this study provides comprehensive insights into the expression patterns of protein-coding genes and non-coding transcripts throughout the HF cycle, and enhancing the understanding of the regulatory mechanisms underlying mammalian hair fiber development.

Mechanisms and therapeutic implications of gene expression regulation by circRNA-protein interactions in cancer

Circular RNAs (circRNAs) have garnered substantial attention due to their distinctive circular structure and gene regulatory functions, establishing them as a significant class of functional non-coding RNAs in eukaryotes. Studies have demonstrated that circRNAs can interact with RNA-binding proteins (RBPs), which play crucial roles in tumorigenesis, metastasis, and drug response in cancer by influencing gene expression and altering the processes of tumor initiation and progression. This review aims to summarize the recent advances in research on circRNA-protein interactions (CPIs) and discuss the functions and mode of action of CPIs at various stages of gene expression, including transcription, splicing, translation, and post-translational modifications in the context of cancer. Additionally, we explore the role of CPIs in tumor drug resistance to gain a deeper understanding of their potential applications in the development of new anti-cancer therapeutic approaches.

CeRNA profiling and the role in regulating gonadal development in gold pompano

BACKGROUND

The golden pompano (Trachinotus ovatus) is an economically significant warm-water aquaculture species in China. The time required for sexual maturity of T. ovatus is relatively long. Consequently, it has prompted researchers to investigate gonadal development process of this fish. To gain further insight into the function of competing endogenous RNA (ceRNA) in the gonads of T. ovatus and the regulatory mechanism of the ceRNA network, whole transcriptome libraries were constructed from the testes and ovaries.

RESULTS

Overall, a total of 96 differentially expressed microRNAs (DE-miRNAs), 2,338 differentially expressed messenger RNAs (DE-mRNAs), 973 differentially expressed long non-coding RNAs (DE-lncRNAs), and 94 differentially expressed circular RNAs (DE-circRNAs) were identified. Additionally, a ceRNA network was constructed, and enrichment analysis confirmed the involvement of numerous pathways in reproduction and gonadal development, including the TGF-β signaling pathway and GnRH signaling pathway. The ceRNA network analysis revealed that the oni-let-7d-1-p3 and PC-3p-112794_13 may play significant roles in T. ovatus gonadal development. And we have observed a possible relationship related to gonadal development involving R-spondin-1 (Rspo1), oni-let-7d-1-p3, and MSTRG.14909.1 (lnc-TGFβR). Dual-luciferase gene reporter system and fluorescence in situ hybridization analyses preliminary verified the regulation relationship between Rspo1 and oni-let-7d-1-p3, as well as lnc-TGFβR and oni-let-7d-1-p3 in the cytoplasm of sertoli cells.

CONCLUSION

It is hypothesized that the lnc-TGFβR functions as a sponge for oni-let-7d-1-p3, participating in regulating the process of testis development. These findings could enhance our understanding of ncRNAs in gonadal development. It also provides new insight into the function of ncRNAs and the regulatory relationship of ceRNA between males and females. These results might contribute to discussions on the regulation of ncRNA during gametogenesis.

Elucidating circRNA-miRNA-mRNA competing endogenous regulatory RNA network during leaf rust pathogenesis in wheat (Triticum aestivum L.)

Advancements in bioinformatic tools and breakthroughs in high throughput RNA sequencing have unveiled the potential role of non-coding RNAs in influencing the overall expression of disease-responsive genes. Owing to the increasing need to develop resilient crop varieties against environmental constraints, our study explores the functional relationship of various non-coding RNAs in wheat during leaf rust pathogenesis. MicroRNAs (miRNAs) and circular RNAs (circRNAs) were retrieved from SAGE and RNA-Seq libraries, respectively, in the susceptible (HD2329) and resistant (HD2329 + Lr28) wheat Near-Isogenic Lines (NILs). Here we explored the previously published circRNAs for their differential expression and correlated the data with the differentially expressed miRNAs (DEMs) through various in silico methods to acquire the target miRNAs of circRNAs and the downstream target mRNAs of miRNAs. Finally, a competing endogenous RNA (ceRNAs) regulatory network was constructed and validated through RT-qPCR method. We have identified the ceRNA regulatory network of four differentially expressed circRNAs (DECs) and five DEMs to highlight their crucial roles in the robust enhancement of the temporal expression profiles of five defense responsive genes (mRNAs) in wheat NILs against leaf rust infection. The study confirms the synergistic expression of circRNAs and mRNAs with an antagonistic correlation with the expression profile of the corresponding miRNAs. The vital role of leaf rust-resistant gene Lr28 has also been highlighted for driving the efficiency of the circRNAs to upregulate target gene expression. Thus, understanding the circRNA-miRNA-target gene interaction during leaf rust pathogenesis can help to identify stress-specific regulatory biomarkers to enhance defense responses in wheat for improved resilience through multi-omics integration of transcriptomics, proteomics and metabolomics.

Heat Tolerance-Associated circRNA3685 Regulates Apoptosis and Autophagy in Bovine Mammary Epithelial Cells via Sponging bta-miR-138

Heat stress negatively affects dairy cow production, and health, leading to significant losses. Identifying mechanisms associated with heat tolerance is crucial for developing breeding strategies. Circular RNAs (circRNAs), a type of noncoding RNA, regulate cell functions like autophagy, apoptosis and proliferation. In this study, dairy cows were classified into heat stress tolerant (HST, n = 15) and heat stress sensitive (HSS, n = 15) groups based on respiratory and drooling score during the heat stress. A significant difference in milk production decline was observed, with the HST group showing less decline, indicating better heat tolerance. Blood transcriptomics analysis identified 166 differentially expressed circRNAs with circRNA3685 being highlighted as a key candidate linked to heat tolerance. Overexpression of circRNA3685 in bovine mammary (MAC-T) cells inhibited autophagy and apoptosis. The circRNA3685 was found to interact with bta-miR-138, targeting HIF1A. These findings provide insights into circRNAs' role in heat stress adaptation in dairy cows.

Comparative analysis of the whole transcriptome landscapes of muscle and adipose tissue in Qinchuan beef cattle

BACKGROUND

Muscle and adipose tissue are the most critical indicators of beef quality, and their development and function are regulated by noncoding RNAs (ncRNAs). However, the differential regulatory mechanisms of ncRNAs in muscle and adipose tissue remain unclear.

RESULTS

In this study, 2,343 differentially expressed mRNAs (DEMs), 235 differentially expressed lncRNAs (DELs), 95 differentially expressed circRNAs (DECs) and 54 differentially expressed miRNAs (DEmiRs) were identified in longissimus dorsi muscle (LD), subcutaneous fat (SF) and perirenal fat (VF) in Qinchuan beef cattle. The results of functional enrichment analysis showed that DEMs, DELs, DECs and DEmiRs were enriched in biological processes related to development and function of muscle and fat deposition, including skeletal muscle contraction, muscle organ development, PPAR signaling pathway, fatty acid metabolism and MAPK signaling pathway. Based on the competing endogenous RNA (ceRNA) regulatory mechanism, we constructed a lncRNA/circRNA-miRNA-mRNA network consisting of 6 circRNAs, 5 lncRNAs, 6 miRNAs and 27 mRNAs. Among them, 55 ceRNA axes were involved, including circRNA12990 - bta-miR-133a_L-1R + 1 - MYO6/ZEB2, circRNA2893/MSTRG.28538.1/MSTRG.11613.4 - pma-miR-145-5p_R + 2 - EYA4 and MSTRG.26982.1 - bta-let-7e_R + 1 - RBM40.

CONCLUSIONS

This study identified a group of differentially expressed mRNAs, lncRNAs, circRNAs and miRNAs between muscle and adipose tissue and constructed a potential ceRNA regulatory network, which may serve as a foundation for studying the differential regulatory roles of ncRNAs in the development and function of muscle and adipose tissue.

Circular RNAs in coronary heart disease: From molecular mechanism to promising clinical application (Review)

Coronary heart disease (CHD) remains a leading cause of morbidity and mortality worldwide, posing a substantial public health burden. Despite advancements in treatment, the complex etiology of CHD necessitates ongoing exploration of novel diagnostic markers and therapeutic targets. Circular RNAs (circRNAs), a distinct class of non‑coding RNAs with a covalently closed loop structure, have emerged as significant regulators in various diseases, including CHD. Their high stability, tissue‑specific expression and evolutionary conservation underscore their potential as biomarkers and therapeutic agents in CHD. This review discusses the current knowledge on circRNAs in the context of CHD and explores the molecular mechanisms by which circRNAs influence the pathophysiology of CHD, including cardiomyocyte death, endothelial injury, vascular dysfunction and inflammation. It also summarizes the emerging evidence highlighting the differential expression of circRNAs in patients with CHD and their potential utilities as non‑invasive diagnostic and prognostic biomarkers and therapeutic targets for this disease.

Construction of AMPK-related circRNA network in mouse myocardial ischemia-reperfusion injury model

OBJECTIVE

To screen Myocardial ischemia-reperfusion Injury in mice. adenosine monophate-activatedprotein kinase (AMPK) -related differentially expressed circularRNA (circRNA) in MIRI model, Ampk-related circRNA network was drawn to provide possible ideas for the prevention and treatment of MIRI.

METHODS

The mouse MIRI model was constructed by ligation of the left anterior descending artery. After the model was successfully established, the related indicators of cardiac function were detected, and high-throughput sequencing was performed on the myocardial tissue of the mice.

RESULTS

MIRI model was successfully constructed, and two AMPK related differentially expressed loops (novel_circ_043550 and novel_circ_035243) were screened out. A circRNA-miRNA-mRNA network consisting of 2 circRNA, 28 microRNA(miRNA) and 229 messengerRNA (mRNA) was constructed.

CONCLUSIONS

This study reveals the differential expression of several AMPK-related circRNAs in MIRI in mice, and the AMPK-related circRNA regulatory network is constructed, suggesting that AMPK-related circRNA may have potential clinical application prospects as a potential molecular marker and therapeutic target for MIRI.

Identification and functional analysis of circular RNA expression profiles associated with ammonia exposure in chicken lungs

Ammonia acts as a detrimental atmospheric pollutant, posing a sever threat to respiratory tract health and causing lung injury in humans and animals. Circular RNAs (circRNAs) are a distinctive class of non-coding RNA generated by back-splicing of linear RNA, implicated in various biological processes. However, their role in the immune response of chicken lungs to ammonia exposure remains unclear. In this study, we examined the expression profiles of circRNAs in chicken lungs under ammonia stimulation. In total, 61 differentially expressed (DE) circRNAs were identified between the ammonia exposure and control groups, including 17 up-regulated and 44 down-regulated circRNAs. The source genes of these DE circRNAs were predominantly enriched in Influenza A, SNARE interactions in vesicular transport, and Notch signaling pathway. Notably, nine DE circRNAs (circNBAS, circMTIF2, circXPO1, circSNX24, circRAB11A, circARID3B, circUSP54, circPPARA, and circERG) were selected for validation the reliability and authenticity of RNA-seq data. Results showed the back-splicing circular structure, as well as the reliability and accuracy of RNA-seq data in quantifying circRNA expression, as the RT-qPCR results were in agreement with the RNA-seq data. Moreover, we constructed the circRNA-miRNA-mRNA regulatory networks and identified several regulatory networks in chicken lungs under ammonia stimulation, including circRAB11A-gga-miR-191b-3p-BRD2 and circARID3B-gga-miR-1696-CKS2. Taken together, our study delineates the circRNA expression profile and their potential roles in the immune response of chicken lungs to ammonia exposure. These findings offer insights into molecular mechanisms that may mitigate diseases associated with ammonia induced respiratory tract pollution in humans and animals.

CircRNA profiling of skeletal muscle satellite cells in goats reveals circTGFβ2 promotes myoblast differentiation

BACKGROUND

Circular RNAs (circRNAs) function as essential regulatory elements with pivotal roles in various biological processes. However, their expression profiles and functional regulation during the differentiation of goat myoblasts have not been thoroughly explored. This study conducts an analysis of circRNA expression profiles during the proliferation phase (cultured in growth medium, GM) and differentiation phase (cultured in differentiation medium, DM1/DM5) of skeletal muscle satellite cells (MuSCs) in goats.

RESULTS

A total of 2,094 circRNAs were identified, among which 84 were differentially expressed as determined by pairwise comparisons across three distinct groups. Validation of the expression levels of six randomly selected circRNAs was performed using reverse transcription PCR (RT-PCR) and quantitative RT-PCR (qRT-PCR), with confirmation of their back-splicing junction sites. Enrichment analysis of the host genes associated with differentially expressed circRNAs (DEcircRNAs) indicated significant involvement in biological processes such as muscle contraction, muscle hypertrophy, and muscle tissue development. Additionally, these host genes were implicated in key signaling pathways, including Hippo, TGF-beta, and MAPK pathways. Subsequently, employing Cytoscape, we developed a circRNA-miRNA interaction network to elucidate the complex regulatory mechanisms underlying goat muscle development, encompassing 21 circRNAs and 47 miRNAs. Functional assays demonstrated that circTGFβ2 enhances myogenic differentiation in goats, potentially through a miRNA sponge mechanism.

CONCLUSION

In conclusion, we identified the genome-wide expression profiles of circRNAs in goat MuSCs during both proliferation and differentiation phases, and established that circTGFβ2 plays a role in the regulation of myogenesis. This study offers a significant resource for the advanced exploration of the biological functions and mechanisms of circRNAs in the myogenesis of goats.

Synthetic circRNA therapeutics: innovations, strategies, and future horizons

Small molecule drugs are increasingly emerging as innovative and effective treatments for various diseases, with mRNA therapeutics being a notable representative. The success of COVID-19 vaccines has underscored the transformative potential of mRNA in RNA therapeutics. Within the RNA family, there is another unique type known as circRNA. This single-stranded closed-loop RNA molecule offers notable advantages over mRNA, including enhanced stability and prolonged protein expression, which may significantly impact therapeutic strategies. Furthermore, circRNA plays a pivotal role in the pathogenesis of various diseases, such as cancers, autoimmune disorders, and cardiovascular diseases, making it a promising clinical intervention target. Despite these benefits, the application of circRNA in clinical settings remains underexplored. This review provides a comprehensive overview of the current state of synthetic circRNA therapeutics, focusing on its synthesis, optimization, delivery, and diverse applications. It also addresses the challenges impeding the advancement of circRNA therapeutics from bench to bedside. By summarizing these aspects, the review aims to equip researchers with insights into the ongoing developments and future directions in circRNA therapeutics. Highlighting both the progress and the existing gaps in circRNA research, this review offers valuable perspectives for advancing the field and guiding future investigations.

Whole-transcriptome sequencing revealed the ceRNA regulatory network during the proliferation and differentiation of goose myoblast

The Shitou goose, the largest meat-type goose breed, is an ideal model for offering insights into enhancing meat production efficiency through understanding its genetic regulation of muscle development. Here, through whole-transcriptomic analysis of embryonic leg muscles, we identified 847 differentially expressed genes (DEG), 244 differentially expressed lncRNAs (DEL), 37 differentially expressed circRNAs (DEC), and 84 differentially expressed miRNAs (DEM). Gene ontology (GO) analysis highlighted the significant enrichment of differentially expressed RNAs in muscle structure development, actin filament-based processes, and the actin cytoskeleton pathway. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified pathways associated with the FoxO signaling pathway, AMPK signaling pathway, Wnt signaling pathway and calcium signaling pathway. Furthermore, we utilized Miranda, TargetScan, and miRDB to identify regulatory networks that involve interactions between lncRNA-mRNA, circRNA-mRNA, miRNA-mRNA, lncRNA-miRNA-mRNA, and circRNA-miRNA-mRNA, which regulated the growth and development of skeletal muscle. Notably, differentially expressed genes within the ceRNA network were most significantly enriched in the regulation of actin cytoskeletal organization. Additionally, a lncRNA/circRNA-miRNA-mRNA ceRNA network related to muscle growth and development was constructed based on protein-protein interaction (PPI) analysis and hub genes selection using Cytoscape. This further elucidated the regulatory roles of noncoding RNAs (ncRNA) in the formation of muscle fibers in Shitou goose. In summary, this study provides a valuable transcriptional regulatory network for goose muscle development laying the groundwork for further exploration of the molecular regulatory mechanisms underlying the excellent meat production performance of Shitou goose.

An AI Agent for Fully Automated Multi-Omic Analyses

With the fast-growing and evolving omics data, the demand for streamlined and adaptable tools to handle bioinformatics analysis continues to grow. In response to this need, Automated Bioinformatics Analysis (AutoBA) is introduced, an autonomous AI agent designed explicitly for fully automated multi-omic analyses based on large language models (LLMs). AutoBA simplifies the analytical process by requiring minimal user input while delivering detailed step-by-step plans for various bioinformatics tasks. AutoBA's unique capacity to self-design analysis processes based on input data variations further underscores its versatility. Compared with online bioinformatic services, AutoBA offers multiple LLM backends, with options for both online and local usage, prioritizing data security and user privacy. In comparison to ChatGPT and open-source LLMs, an automated code repair (ACR) mechanism in AutoBA is designed to improve its stability in automated end-to-end bioinformatics analysis tasks. Moreover, different from the predefined pipeline, AutoBA has adaptability in sync with emerging bioinformatics tools. Overall, AutoBA represents an advanced and convenient tool, offering robustness and adaptability for conventional multi-omic analyses.

Comprehensive circular RNA profiling in various sheep tissues

Despite the scientific relevance of circular RNAs (circRNAs), the study of these RNAs in non-model organisms, especially in sheep, is still in its infancy. On the other hand, while some studies have focused on sheep circRNA identification in a limited number of tissues, there is a lack of comprehensive analysis that profile circRNA expression patterns across the tissues not yet investigated. In this study, 61 public RNA sequencing datasets from 12 different tissues were uniformly analyzed to identify circRNAs, profile their expression and investigate their various characteristics. We reported for the first time a circRNA expression landscape with functional annotation in sheep tissues not yet investigated including hippocampus, BonMarrowMacrophage, left-ventricle, thymus, ileum, reticulum and 23-day-embryo. A stringent computational pipeline was employed and 8919 exon-derived circRNAs with high confidence were identified, including 88 novel circRNAs. Tissue-specificity analysis revealed that 3059 circRNAs were tissue-specific, which were also more specific to the tissues than linear RNAs. The highest number of tissue-specific circRNAs was found in kidney, hippocampus and thymus, respectively. Co-expression analysis revealed that expression of circRNAs may not be affected by their host genes. While most of the host genes produced more than one isoform, only one isoform had dominant expression across the tissues. The host genes of the tissue-specific circRNAs were significantly enriched in biological/pathways terms linked to the important functions of their corresponding tissues, suggesting potential roles of circRNAs in modulating physiological activity of those tissues. Interestingly, functional terms related to the regulation and various signaling pathways were significantly enriched in all tissues, suggesting some common regulatory mechanisms of circRNAs to modulate the physiological functions of tissues. Finding of the present study provide a valuable resource for depicting the complexity of circRNAs expression across tissues of sheep, which can be useful for the field of sheep genomic and veterinary research.

Hsa_circ_0048764 facilitates the progression of non-small cell lung cancer by targeting miR-1178-3p/HMGA1 axis

Non-small cell lung cancer (NSCLC) remains a highly lethal disease, with a lack of fully established biomarkers and therapies. Circular RNAs (circRNAs) have emerged as powerful regulators of gene expression in multiple cancers. The role of circRNAs in NSCLC progression is still not well understood. In this study, GEO database analysis and qRT-PCR results revealed that hsa_circ_0048764 (circ_0048764) was overexpressed in NSCLC tissues and associated with poorer overall survival in patients with NSCLC. Functional assays demonstrated that silencing circ_0048764 inhibited NSCLC cell proliferation and metastasis. Bioinformatics analysis identified miR-1178-3p as having complementary binding sites with circ_0048764, a finding further validated by the dual-luciferase reporter assay. Additionally, predictions from the Starbase3.0 database, along with cellular experiments, revealed that miR-1178-3p regulates HMGA1 expression in NSCLC. Taken together, our findings suggest that circ_0048764 promotes NSCLC progression by enhancing HMGA1 expression through sponging miR-1178-3p, offering potential therapeutic targets for NSCLC treatment.

Accurate assembly of circular RNAs with TERRACE

Circular RNA (circRNA) is a class of RNA molecules that forms a closed loop with their 5' and 3' ends covalently bonded. CircRNAs are known to be more stable than linear RNAs, have distinct properties and functions, and are promising biomarkers. Existing methods for assembling circRNAs heavily rely on the annotated transcriptomes, hence exhibiting unsatisfactory accuracy without a high-quality transcriptome. We present TERRACE, a new algorithm for full-length assembly of circRNAs from paired-end total RNA-seq data. TERRACE uses the splice graph as the underlying data structure that organizes the splicing and coverage information. We transform the problem of assembling circRNAs into finding paths that "bridge" the three fragments in the splice graph induced by back-spliced reads. We adopt a definition for optimal bridging paths and a dynamic programming algorithm to calculate such optimal paths. TERRACE features an efficient algorithm to detect back-spliced reads missed by RNA-seq aligners, contributing to its much-improved sensitivity. It also incorporates a new machine-learning approach trained to assign a confidence score to each assembled circRNA, which is shown to be superior to using abundance for scoring. On both simulations and biological data sets, TERRACE consistently outperforms existing methods by a large margin in sensitivity while achieving better or comparable precision. In particular, when the annotations are not provided, TERRACE assembles 123%-413% more correct circRNAs than state-of-the-art methods. TERRACE presents a significant advance in assembling full-length circRNAs from RNA-seq data, and we expect it to be widely used in future research on circRNAs.

Full-length circRNA sequencing method using low-input RNAs and profiling of circRNAs in MPTP-PD mice on a nanopore platform

Considering the importance of accurate information of full-length (FL) transcripts in functional analysis, researchers prefer to develop new sequencing methods based on third-generation sequencing (TGS) rather than short-read sequencing. Several FL circRNA sequencing strategies have been developed. However, the current methods are inapplicable to low-biomass samples, since a large amount of total RNAs are acquired for circRNA enrichment before library preparation. In this work, we developed an effective method to detect FL circRNAs from a nanogram level (1-100 ng) of total RNAs based on a nanopore platform. Additionally, prior to the library preparation process, we added a series of 24 nt barcodes for each sample to reduce the cost and operating time. Using this method, we profiled circRNA expression in the striatum, hippocampus and cerebral cortex of a Parkinson's disease (PD) mouse model. Over 6% of reads were effective for FL circRNA identification in most datasets. Notably, a reduction in the RNA initial input resulted in a lower correlation between replicates and the detection efficiency for longer circRNA, but the lowest input (1 ng) was able to detect numerous FL circRNAs. Next, we systematically identified over 263 934 circRNAs in PD and healthy mice using the lower-input FL sequencing method, some of which came from 50.52% of PD-associated genes. Moreover, significant changes were observed in the circRNA expression pattern at an isoform level, and high-confidence protein translation evidence was predicted. Overall, we developed an effective method to characterize FL circRNAs from low-input samples and provide a comprehensive insight into the biological function of circRNAs in PD at an isoform level.

A Representation Learning Approach for Predicting circRNA Back-Splicing Event via Sequence-Interaction-Aware Dual Encoder

Circular RNAs (circRNAs) play a crucial role in gene regulation and association with diseases because of their unique closed continuous loop structure, which is more stable and conserved than ordinary linear RNAs. As fundamental work to clarify their functions, a large number of computational approaches for identifying circRNA formation have been proposed. However, these methods fail to fully utilize the important characteristics of back-splicing events, i.e., the positional information of the splice sites and the interaction features of its flanking sequences, for predicting circRNAs. To this end, we hereby propose a novel approach called SIDE for predicting circRNA back-splicing events using only raw RNA sequences. Technically, SIDE employs a dual encoder to capture global and interactive features of the RNA sequence, and then a decoder designed by the contrastive learning to fuse out discriminative features improving the prediction of circRNAs formation. Empirical results on three real-world datasets show the effectiveness of SIDE. Further analysis also reveals that the effectiveness of SIDE.

Whole-transcriptome analyses of ovine lung microvascular endothelial cells infected with bluetongue virus

Bluetongue virus (BTV) infection induces profound and intricate changes in the transcriptional profile of the host to facilitate its survival and replication. However, there have been no whole-transcriptome studies on ovine lung microvascular endothelial cells (OLMECs) infected with BTV. In this study, we comprehensively analysed the whole-transcriptome sequences of BTV-1 serotype-infected and mock-infected OLMECs and subsequently performed bioinformatics differential analysis. Our analysis revealed 1215 differentially expressed mRNA transcripts, 82 differentially expressed long noncoding RNAs (lncRNAs) transcripts, 63 differentially expressed microRNAs (miRNAs) transcripts, and 42 differentially expressed circular RNAs (circRNAs) transcripts. Annotation from Gene Ontology, enrichment from the Kyoto Encyclopedia of Genes and Genomes, and construction of endogenous competing RNA network analysis revealed that the differentially expressed RNAs primarily participated in viral sensing and signal transduction pathways, antiviral and immune responses, inflammation, and extracellular matrix (ECM)-related pathways. Furthermore, protein‒protein interaction network analysis revealed that BTV may regulate the conformation of ECM receptor proteins and change their biological activity through a series of complex mechanisms. Finally, on the basis of real-time fluorescence quantitative polymerase chain reaction results, the expression trends of the differentially expressed RNA were consistent with the whole-transcriptome sequencing data, such as downregulation of the expression of COL4A1, ITGA8, ITGB5, and TNC and upregulation of the expression of CXCL10, RNASEL, IRF3, IRF7, and IFIHI. This study provides a novel perspective for further investigations of the mechanism of the ECM in the BTV-host interactome and the pathogenesis of lung microvascular endothelial cells.

Circular RNA expression in turkey skeletal muscle satellite cells is significantly altered by thermal challenge

Introduction

Understanding the genetic mechanisms behind muscle growth and development is crucial for improving the efficiency of animal protein production. Recent poultry studies have identified genes related to muscle development and explored how environmental stressors, such as temperature extremes, affect protein production and meat quality. Non-coding RNAs, including circular RNAs (circRNAs), play crucial roles in modulating gene expression and regulating the translation of mRNAs into proteins. This study examined circRNA expression in turkey skeletal muscle stem cells under thermal stress. The objectives were to identify and quantify circRNAs, assess circRNA abundance following RNAse R depletion, identify differentially expressed circRNAs (DECs), and predict potential microRNA (miRNA) targets for DECs and their associated genes.

Materials and methods

Cultured cells from two genetic lines (Nicholas commercial turkey and The Ohio State Random Bred Control 2) under three thermal treatments: cold (33°C), control (38°C), and hot (43°C) were compared at both the proliferation and differentiation stages. CircRNA prediction and differential expression and splicing analyses were conducted using the CIRIquant pipeline for both the untreated and RNase R depletion treated libraries. Predicted interactions between DECs and miRNAs, as well as the potential impact of circRNA secondary structure on these interactions, were investigated.

Results

A total of 11,125 circRNAs were predicted within the treatment groups, between both untreated and RNase R treated libraries. Differential expression analyses indicated that circRNA expression was significantly altered by thermal treatments and the genetic background of the stem cells. A total of 140 DECs were identified across the treatment comparisons. In general, more DECs within temperature treatment comparisons were identified in the proliferation stage and more DECs within genetic line comparisons were identified in the differentiation stage.

Discussion

This study highlights the significant impact of environmental stressors on non-coding RNAs and their role in gene regulation. Elucidating the role of non-coding RNAs in gene regulation can help further our understanding of muscle development and poultry production, underscoring the broader implications of this research for enhancing animal protein production efficiency.

Exploration and validation of ceRNA regulatory networks in colorectal cancer based on associations whole transcriptome sequencing

Colorectal cancer (CRC) is a wide-spread gastrointestinal cancer that is associated with augmented morbidity and mortality, and we do not yet have a deep understanding of its epidemiology and carcinogenicity. The transcriptome can reveal the complexity and heterogeneity of tumors and uncover new biomarkers or treatment options. In this study, we identified messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs), round RNAs (circRNAs), and microRNAs (miRNAs) using whole-transcriptome sequencing and generated competing endogenous RNA (ceRNA) modulatory axes. We conducted whole transcriptome sequencing on 10 CRC and para-cancer (CRCP) samples and discovered 2465 differentially expressed (DE) mRNAs (DEmRNAs), 77 DE miRNAs (DEmiRNAs). 2852 DE lncRNAs (DElncRNAs) and 1477 DE circRNAs (DEcircRNAs). In addition, utilizing co-DE analysis, we generated the ceRNA axis. Subsequently, we employed the ceRNA axis to identify essential genes and corresponding associations with lncRNAs, circRNAs, and miRNAs in CRC. ceRNA regulatory network including mRNA-miRNA-lncRNA and mRNA-miRNA-circRNA. These modulatory axes potentially modulate the positive regulation of smooth muscle contraction, melanosome, plasma membrane, integral plasma membrane component and so on. Finally, the results of RNA sequencing (RNA-SEQ) were combined with the TCGA and GEO databases, and the DEGs strongly correlated with the TCGA-COAD overall survival (OS) as estimated by univariate cox and logarithmic rank analyses were cross-analyzed, and the co-upregulated DEGs were screened. Among the many DEs, KPNA2 was chosen for additional analysis. Using invitro experimentations, western blot, CCK8, EdU and other experiments were performed to verify the results. We found siRNA-based KPNA2 depletion reduces bladder cancer cells' viability, migratory, and proliferative activities, which showed that the DEmRNA profiles were comparable to the sequencing information, confirming that the sequencing data were very reliable. These evidences highlight the ceRNA regulatory mechanisms in CRC and will aid future research into the molecular mechanisms behind colorectal cancer prevention and treatment.

Whole transcriptome RNA sequencing provides novel insights into the molecular dynamics of ovarian development in mud crab, Scylla paramamosain after mating

Ovarian development in animals is a complicated biological process, requiring the simultaneous coordination among various genes and pathways. To understand the dynamic changes and molecular regulatory mechanisms of ovarian development in mud crab (Scylla paramamosain), both histological observation and whole transcriptome sequencing of ovarian tissues at different mating stages were implemented in this study. The histological results revealed that ovarian development was delayed in unmated females (60 days after courtship behavior but not mating), who exhibited an oocyte diameter of 56.38 ± 15.17 μm. Conversely, mated females exhibited accelerated the ovarian maturation process, with females reaching ovarian stage III (proliferative stage) 23 days after mating and attained an average oocyte diameter of 132.19 ± 15.07 μm. Thus, mating process is essential in promoting the rapid ovarian development in mud crab. Based on the whole transcriptome sequencing analysis, a total of 518 mRNAs, 1502 lncRNAs, 18 circRNAs and 151 miRNAs were identified to be differentially expressed between ovarian tissues at different mating stages. Notably, six differentially expressed genes (DEGs) associated with ovarian development were identified, including ovary development-related protein, red pigment concentrating hormone receptor, G2/mitotic-specific cyclin-B3-like, lutropin-chorio gonadotropic hormone receptor, renin receptor, and SoxB2. More importantly, both DEGs and targets of differentially expressed non-coding RNAs (DEncRNAs) were enriched in renin-angiotensin system, TGF-β signaling, cell adhesion molecules, MAPK signaling pathway, and ECM-receptor interaction, suggesting that these pathways may play significant roles in the ovarian development of mud crabs. Moreover, competition endogenous RNA (ceRNA) networks were constructed while mRNAs were differentially expressed between mating stages were involved in Gene Ontology (GO) biological processes such as developmental process, reproduction, and growth. These findings could provide solid foundations for the future development of female mud crab maturation enhancement strategy, and improve the understanding of the ovarian maturation process in crustaceans.

Circular RNA in cancer

Over the past decade, circular RNA (circRNA) research has evolved into a bona fide research field shedding light on the functional consequence of this unique family of RNA molecules in cancer. Although the method of formation and the abundance of circRNAs can differ from their cognate linear mRNA, the spectrum of interacting partners and their resultant cellular functions in oncogenesis are analogous. However, with 10 times more diversity in circRNA variants compared with linear RNA variants, combined with their hyperstability in the cell, circRNAs are equipped to influence every stage of oncogenesis. This is an opportune time to address the breadth of circRNA in cancer focused on their spatiotemporal expression, mutations in biogenesis factors and contemporary functions through each stage of cancer. In this Review, we highlight examples of functional circRNAs in specific cancers, which satisfy critical criteria, including their physical co-association with the target and circRNA abundance at stoichiometrically valid quantities. These considerations are essential to develop strategies for the therapeutic exploitation of circRNAs as biomarkers and targeted anticancer agents.

CircRNA8388 functions as the sponge for miR-2392 during intestinal regeneration in sea cucumber Apostichopus japonicus

The sea cucumber Apostichopus japonicus can expel internal organs under stress and regenerate them subsequently. However, growth is delayed during regeneration, significantly impacting the industry. Circular RNAs (circRNAs) are single-stranded circular RNA molecules produced through alternative splicing of mRNA precursors. They play crucial roles in regulating gene expression via the ceRNA mechanism. In this study, circRNA profiles of control and regenerated intestines were constructed. A total of 15,874 circRNAs were identified, with a length of 300-350 nucleotides (nt) being the most abundant. Sanger sequencing confirmed the circular structure of circRNA398. Compared with the normal intestine, 50 and 83 differentially expressed circRNAs (DE-circRNAs) were identified in the regenerated intestine at 1 and 3 days post evisceration (dpe), respectively. Gene ontology (GO) terms for signal transduction and development regulation were most significantly enriched in 1dpeVScon and 3dpeVScon treatments, respectively. The dual-luciferase assay revealed that circRNA8388 functions as a sponge for miR-2392, participating in the remodeling of the extracellular matrix (ECM). In conclusion, these findings will contribute to the enhancement of the non-coding RNA database for echinoderms and lay the groundwork for future investigations into circRNA regulation during intestinal regeneration.

N6-methyladenosine modified circPAK2 promotes lymph node metastasis via targeting IGF2BPs/VEGFA signaling in gastric cancer

Circular RNAs (circRNAs) have emerged as key regulators of cancer occurrence and progression, as well as promising biomarkers for cancer diagnosis and prognosis. However, the potential mechanisms of circRNAs implicated in lymph node (LN) metastasis of gastric cancer remain unclear. Herein, we identify a novel N6-methyladenosine (m6A) modified circRNA, circPAK2, which is significantly upregulated in gastric cancer tissues and metastatic LN tissues. Functionally, circPAK2 enhances the migration, invasion, lymphangiogenesis, angiogenesis, epithelial-mesenchymal transition (EMT), and metastasis of gastric cancer in vitro and in vivo. Mechanistically, circPAK2 is exported by YTH domain-containing protein 1 (YTHDC1) from the nucleus to the cytoplasm in an m6A methylation-dependent manner. Moreover, increased cytoplasmic circPAK2 interacts with Insulin-Like Growth Factor 2 mRNA-Binding Proteins (IGF2BPs) and forms a circPAK2/IGF2BPs/VEGFA complex to stabilize VEGFA mRNA, which contributes to gastric cancer vasculature formation and aggressiveness. Clinically, high circPAK2 expression is positively associated with LN metastasis and poor prognosis in gastric cancer. This study highlights m6A-modified circPAK2 as a key regulator of LN metastasis of gastric cancer, thus supporting circPAK2 as a promising therapeutic target and prognostic biomarker for gastric cancer.

Exploring the prognostic value of circular RNAs in pancreatic ductal adenocarcinoma using genome-wide expression profiling

BACKGROUND/OBJECTIVES

Median survival of pancreatic ductal adenocarcinoma (PDAC) is around eight months and new prognostic tools are needed. Circular RNAs (circRNAs) have gained interest in different types of cancer. However, only a few studies have evaluated their potential in PDAC. We aimed to identify the most differentially expressed circRNAs in PDAC compared to controls and to explore their potential as prognostic markers.

METHODS

Using frozen specimens with PDAC and controls, we performed RNA sequencing and identified 20,440 unique circRNAs. A custom code set of capture- and reporter probes for NanoString nCounter analysis was designed to target 152 circRNAs, based on abundancy, differential expression and a literature study. Expression of these 152 circRNAs was examined in 108 formalin-fixed and paraffin-embedded surgical PDAC specimens and controls. The spatial expression of one of the most promising candidates, ciRS-7 (hsa_circ_0001946), was evaluated by chromogenic in situ hybridization (CISH) using multi-punch tissue microarrays (TMAs) and digital imaging analysis.

RESULTS

Based on circRNA expression profiles, we identified different PDAC subclusters. The 30 most differentially expressed circRNAs showed log2 fold changes from -3.43 to 0.94, where circNRIP1 (hsa_circ_0004771), circMBOAT2 (hsa_circ_0007334) and circRUNX1 (hsa_circ_0002360) held significant prognostic value in multivariate analysis. CiRS-7 was absent in PDAC cells but highly expressed in the tumor microenvironment.

CONCLUSIONS

We identified several new circRNAs with biomarker potential in surgically treated PDAC, three of which showed an independent prognostic value. We also found that ciRS-7 is absent in cancer cells but abundant in tumor microenvironment and may hold potential as marker of activated stroma.

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.