miRNA Sponge Research Articles

Reveal the potential molecular mechanism of circRNA regulating immune-related mRNA through sponge miRNA in the occurrence and immune regulation of papillary thyroid cancer

Background Papillary thyroid cancer (PTC) is the most common endocrine malignant tumour. The purpose of this study was to explore the potential molecular mechanism of circRNA regulating immune-related mRNA through sponge miRNA in the occurrence and immune regulation of PTC. Methods All data were downloaded from public databases, such as GEO, Immport and TCGA. Differentially expressed (DE) mRNAs (DEmRNAs), DEmiRNAs and DEcircRNAs were identified using metaMA and limma packages. Subsequently, immune-related DEmRNAs were screened, and circRNA-miRNA-mRNA (ceRNA) regulatory network was constructed. In addition, functional annotation, protein-protein interaction (PPI) network construction, immune cell infiltration analysis and Pearson correlation analysis were performed. Finally, qRT-PCR validation and cell experiments were also performed. Results In total, 2962 DEmRNAs, 78 DEmiRNAs and 51 DEcircRNAs were obtained. Subsequently, 195 immune-related DEmRNAs were obtained based on Immport database. Cytokine-cytokine receptor interaction was the only signalling pathway obtained in KEGG analysis. Then, 8 hub immune-related DEmRNAs were identified based on PPI network and CytoHubba plug-in. Subsequently, ceRNA sub-network containing hub immune-related DEmRNAs was extracted from ceRNA regulatory network. In ceRNA sub-network, hsa_circ_0082182-hsa-miR-18b-5p-FGF1/PDGFC, hsa_circ_0016404-hsa-miR-1275-FGF1/CTSB/IL13RA1, hsa_circ_0070100-hsa-miR-27a-3p/hsa-miR-27b-3p-TGFBR3, hsa_circ_0060055/hsa_circ_0038718-hsa-miR-150-3p-CXCL14, hsa_circ_0030427/hsa_circ_0002917-hsa-miR-22-3p-BMP7 and hsa_circ_0030427/hsa_circ_0002917-hsa-miR-125a-5p-LIFR axes were identified. Moreover, FGF1, PDGFC, CTSB, IL13RA1, TGFBR3, CXCL14, BMP7, LIFR, hsa-miR-125a-5p, hsa-miR-1275, hsa-miR-150-3p, hsa-miR-18b-5p and hsa-miR-27b-3p were also found to have good diagnostic accuracy and may be potential novel diagnostic markers for PTC. XCell analysis showed that the levels of immune cell infiltration (including Tregs, HSC, DC and Monocytes) were significantly different between the PTC and the control groups. Knockdown of the expression of hsa_circ_0082182 significantly inhibits the activity, proliferation, migration and invasion of TPC-1 cells. Conclusion Several circRNA-miRNA-mRNA axes identified in this study may be related to the occurrence, progression and survival of PTC. This lays a theoretical foundation for further understanding the molecular mechanism of PTC, and also contributes to clinical management and research.

Bibliometric Analysis of Global Research on Circular RNA: Current Status and Future Directions.

Circular RNAs (circRNAs) have gained significant attention in recent years. This bibliometric analysis aimed to provide insights into the current state and future trends of global circRNA research. The scientific output on circRNAs from 2010 to 2022 was retrieved from the Web of Science Core Collection with circRNA-related terms as the subjects. Key bibliometric indicators were calculated and evaluated using CiteSpace. A total of 7385 studies on circRNAs were identified. The output and citation number have increased rapidly after 2015. China, the USA, and Germany were top three publishing countries. Currently, circCDR1as, circHIPK3, circPVT1, circSHPRH, and circZNF609 are the most studied circRNAs; and all are related to cancer. The theme of research have shifted from transcript, exon circularization and miRNA sponge topics to the transcriptome, tumor suppressor, and biomarkers, indicating that research interests have evolved from basic toappliedresearch. CircRNAs will continue to be a highly active research area in the near future. From the current understanding of circRNA characterization and regulatory mechanisms as miRNA sponges in cancer, future directions may examine potential diagnostic and therapeutic roles of circRNAs in cancers or the function and mechanism of circRNAs in other diseases.

Circular RNAs Variously Participate in Coronary Atherogenesis.

Over the past decade, numerous studies have shown that circular RNAs (circRNAs) play a significant role in coronary artery atherogenesis and other cardiovascular diseases. They belong to the class of non-coding RNAs and arise as a result of non-canonical splicing of premature RNA, which results in the formation of closed single-stranded circRNA molecules that lack 5'-end caps and 3'-end poly(A) tails. circRNAs have broad post-transcriptional regulatory activity. Acting as a sponge for miRNAs, circRNAs compete with mRNAs for binding to miRNAs, acting as competing endogenous RNAs. Numerous circRNAs are involved in the circRNA-miRNA-mRNA regulatory axes associated with the pathogenesis of cardiomyopathy, chronic heart failure, hypertension, atherosclerosis, and coronary artery disease. Recent studies have shown that сirc_0001445, circ_0000345, circ_0093887, сircSmoc1-2, and circ_0003423 are involved in the pathogenesis of coronary artery disease (CAD) with an atheroprotective effect, while circ_0002984, circ_0029589, circ_0124644, circ_0091822, and circ_0050486 possess a proatherogenic effect. With their high resistance to endonucleases, circRNAs are promising diagnostic biomarkers and therapeutic targets. This review aims to provide updated information on the involvement of atherogenesis-related circRNAs in the pathogenesis of CAD. We also discuss the main modern approaches to detecting and studying circRNA-miRNA-mRNA interactions, as well as the prospects for using circRNAs as biomarkers and therapeutic targets for the treatment of cardiovascular diseases.

Abstract P2153: A Long Noncoding RNA Plentiful In Cardiosphere-derived Cell Extracellular Vesicles (CDC-EVs), BCYRN1, And Its Short Synthetic Derivatives Enhance Regulatory T Cell (Treg) Proliferation, Migration, And Activation

Background: By modulating inflammation, Treg cells influence outcomes in myocardial infarction (MI). Here, we test the hypothesis that BCYRN1 (Brain Cytoplasmic RNA 1) and BCYRN1-derived binding small sequences (BDSSs) are cardioprotective by activating Tregs. Methods: RNA sequencing identified BCYRN1 as plentiful in cardiosphere-derived cell extracellular vesicles (CDC-EVs), validated by qPCR. RNA pulldown and luciferase assays probed BCYRN1's potential function as a miRNA sponge. We assessed BCYRN1 and BDSS effects on Treg proliferation (Cell Counting Kit-8), migration (trans-well migration), and IL-10 (qPCR and ELISA). In vivo , MI was induced in C57BL/6 mouse by left coronary artery ligation for 45 minutes followed by 15 minutes reperfusion. Afterwards, mice received (via tail vein) CDC-EV-BCYRN1 (CDC-EVs overexpressing BCYRN1), BDSSs, mut-BDSSs (scrambled inactive versions of BDSS) or vehicle (PBS). MI size (by TTC staining) and infiltrating Treg (by flow cytometry) were assessed 72 hrs post-MI. Findings: BCYRN1 was found to contain putative binding sites for miR-138, miR-150 and miR-98; these miRs target ATG7, CCR6 and IL-10 mRNAs, respectively. BCYRN1 serves as a miRNA sponge, leading to Treg cell ATG7/autophagy dependent proliferation (3.0± 0.1 fold increase, N=5), CCR-6 dependent migration (1.8 ± 0.1 fold increase, N=5) and increased IL-10 production (fold increase, qPCR: 2.6 ± 0.4, N=6 and ELISA: 6.1 ± 0.8, N=5). Lipid nanoparticles containing a cocktail of 3BDSSs likewise induce Treg cell proliferation (1.9± 0.6 fold increase, N=6), migration (1.3± 0.2 fold increase, N=6), and IL-10 induction (6.8± 0.5 fold increase, N=6). In vivo (N=5/group), CDC-EV-BCYRN1 (but not vehicle) and BDSS cocktail (but not mut-BDSS) induced Treg infiltration, proliferation and IL10 production in the heart with a concomitant decrease of infarct size. Conclusions: A single LncRNA (BCYRN1) and shorter synthetic derivatives mimic the effects of CDC-EV on Treg in vitro and in vivo . Our study provides a novel approach, targeting Treg, to treat MI. This approach could be useful for other diseases where increased Treg activity is a therapeutic goal (e.g. autoimmune disorders).

Abstract P3036: Circular RNA Decoys Targeting MiR-146a As A Promising Therapeutic Strategy To Improve Vascular Regeneration

Heart failure and cardiac remodeling following myocardial infarction (MI) depend on capillary density and neovascularization. MicroRNAs (miRNAs), which are small non-coding RNAs that modulate gene expression, play a major role in the pathogenesis of these conditions. Inhibition of these pathways through miRNA sponges, such as antagomiRs or circular decoys (circRNAs), might represent a therapeutic approach for MI. Here, we evaluate the role of miR-146a and present a promising treatment strategy using synthetically designed circular decoys. miRNA-146a expression was analyzed in human vascular cells and mice tissue following either myocardial infarction or hind limb ischemia. CircRNAs were synthetically designed and evaluated. Methods to characterize the effect of inhibition of miR-146a included the quantification of the target gene and protein expression and analysis of cellular functions.miR-146a was significantly upregulated in vitro in senescent cells ( P <0.05) and in vivo in the ischemic myocardium following ligation of the LAD ( P <0.001) in C57BL/6 mice. A circular RNA decoy targeting miR-146a was successfully designed and transfected into vascular cells in vitro . The following analysis showed a significant target upregulation for NOX4, KLF4, and TRAF6 ( P <0.001) after circRNA transfection, also compared to antagomiR transfected cells. Functional analysis revealed improved migration and proliferation capacity in vascular endothelial cells ( P <0.05). First results indicate that inhibition of the upregulation of endothelial miR-146a in mice results in significantly enhanced angiogenesis and revascularization ( P <0.05) accompanied by a significantly reduced myocardial infarct size ( P <0.01) and preserved cardiac function post-MI ( P <0.01). In summary, we could identify miR-146a as a critical regulator of angiogenesis and vascular regeneration, and present a first strategy for angiogenic therapy of ischemic diseases. However, in vitro analysis showed a higher efficiency of circRNAs in the context of inhibiting miR-146a functions in vascular cells. CircRNAs are more stable and more efficient when transfected, compared to antagomiRs, and might be a better alternative and a realistic approach for future clinical studies.

Exosomal circCNOT6L Regulates Astrocyte Apoptotic Signals Induced by Hypoxia Exposure Through miR99a-5p/SERPINE1 and Alleviates Ischemic Stroke Injury.

Circular RNAs are involved in intervention strategies for treating ischemic stroke (IS). However, circCNOT6L (hsa_circ_0006168) has not yet been reported in IS. Thus, we aimed to explore the potential role of circCNOT6L and its molecular mechanism in IS. In this study, we first found that the expression of both exosomal circCNOT6L (P = 0.0006) and plasma circCNOT6L (P = 0.0054) was down-regulated in IS patients compared with controls. Clinically, a negative correlation was observed between the relative expression level of circCNOT6L and the National Institutes of Health Stroke Scale (NIHSS) score and infarct volume of the brain. Simultaneously, the relative expression level of circCNOT6L was negatively associated with multiple risk factors for IS, such as mean platelet volume (MPV), red cell distribution width (RDW), very low-density lipoprotein (VLDL), and serum potassium, whereas it was positively correlated with high-density lipoprotein (HDL). In vitro, circCNOT6L silencing blocked cell viability and proliferation, while it promoted cell apoptosis of astrocytes undergoing oxygen-glucose deprivation/reperfusion (OGD/R) treatment. Mechanistically, the RNA antisense purification (RAP) assay and luciferase reporter assay revealed that circCNOT6L acts as a miRNA sponge to absorb miR-99a-5p and then regulates the expression of serine proteinase inhibitor (SERPINE1). In the further rescue experiment, overexpressing SERPINE1 could rescue the cell apoptotic signals due to circCNOT6L depletion. In conclusion, CircCNOT6L attenuated the cell apoptotic signal of astrocytes via the miR99a-5p/SERPINE1 axis and then alleviated injury after hypoxia induced by ischemic stroke.

Dexmedetomidine attenuates neuroinflammation and microglia activation in LPS-stimulated BV2 microglia cells through targeting circ-Shank3/miR-140-3p/TLR4 axis.

It has been shown that dexmedetomidine (Dex) could attenuate postoperative cognitive dysfunction (POCD) via targeting circular RNAs (circRNAs). Circ-Shank3 has been found to be involved in the neuroprotective effects of Dex against POCD. However, the role of circ-Shank3 in POCD remains largely unknown. Reverse transcription quantitative PCR (RT-qPCR) was performed to detect circ-Shank3 and miR-140-3p levels in lipopolysaccharide (LPS)-treated microglia BV-2 cells in the absence or presence of Dex. The relationship among circ-Shank3, miR-140-3p and TLR4 was confirmed by dual-luciferase reporter assay. Additionally, Western blot and immunofluorescence (IF) assays were conducted to evaluate TLR4, p65 and Iba-1 or CD11b levels in cells. In this study, we found that Dex notably decreased circ-Shank3 and TLR4 levels and elevated miR-140-3p level in LPS-treated BV2 cells. Mechanistically, circ-Shank3 harbor miR-140-3p, functioning as a miRNA sponge, and then miR-140-3p targeted the 3'-UTR of TLR4. Additionally, Dex treatment significantly reduced TLR4 level and phosphorylation of p65, and decreased the expressions of microglia markers Iba-1 and CD11b in LPS-treated BV2 cells. As expected, silenced circ-Shank3 further reduced TLR4, p65 and Iba-1 and CD11b levels in LPS-treated BV2 cells in the presence of Dex, whereas these phenomena were reversed by miR-140-3p inhibitor. Collectively, our results found that Dex could attenuate the neuroinflammation and microglia activation in BV2 cells exposed to LPS via targeting circ-Shank3/miR-140-3p/TLR4 axis. Our results might shed a new light on the mechanism of Dex for the treatment of POCD.

Interactions between circRNAs and miR-141 in Cancer: From Pathogenesis to Diagnosis and Therapy.

The function of non-coding RNAs (ncRNAs) in the pathogenesis and development of cancer is indisputable. Molecular mechanisms underlying carcinogenesis involve the aberrant expression of ncRNAs, including circular RNAs (circRNAs), and microRNAs (miRNAs). CircRNAs are a class of single-stranded, covalently closed RNAs responsible for maintaining cellular homeostasis through their diverse functions. As a part of the competing endogenous RNA (ceRNAs) network, they play a central role in the regulation of accessibility of miRNAs to their mRNA targets. The interplay between these molecular players is based on the primary role of circRNAs that act as miRNAs sponges, and the circRNA/miRNA imbalance plays a central role in different pathologies including cancer. Herein, we present the latest state of knowledge about interactions between circRNAs and miR-141, a well-known member of the miR-200 family, in malignant transformation, with emphasis on the biological role of circRNA/miR-141/mRNA networks as a future target for novel anti-cancer therapies.

Identification and characterization of circRNAs in peri-implantation endometrium between Yorkshire and Erhualian pigs

BackgroundOne of the most critical periods for the loss of pig embryos is the 12th day of gestation when implantation begins. Recent studies have shown that non-coding RNAs (ncRNAs) play important regulatory roles during pregnancy. Circular RNAs (circRNAs) are a kind of ubiquitously expressed ncRNAs that can directly regulate the binding proteins or regulate the expression of target genes by adsorbing micro RNAs (miRNA).ResultsWe used the Illumina Novaseq6,000 technology to analyze the circRNA expression profile in the endometrium of three Erhualian (EH12) and three Yorkshire (YK12) pigs on day 12 of gestation. Overall, a total of 22,108 circRNAs were identified. Of these, 4051 circRNAs were specific to EH12 and 5889 circRNAs were specific to YK12, indicating a high level of breed specificity. Further analysis showed that there were 641 significant differentially expressed circRNAs (SDEcircRNAs) in EH12 compared with YK12 (FDR < 0.05). Functional enrichment of differential circRNA host genes revealed many pathways and genes associated with reproduction and regulation of embryo development. Network analysis of circRNA-miRNA interactions further supported the idea that circRNAs act as sponges for miRNAs to regulate gene expression. The prediction of differential circRNA binding proteins further explored the potential regulatory pathways of circRNAs. Analysis of SDEcircRNAs suggested a possible reason for the difference in embryo survival between the two breeds at the peri-implantation stage.ConclusionsTogether, these data suggest that circRNAs are abundantly expressed in the endometrium during the peri-implantation period in pigs and are important regulators of related genes. The results of this study will help to further understand the differences in molecular pathways between the two breeds during the critical implantation period of pregnancy, and will help to provide insight into the molecular mechanisms that contribute to the establishment of pregnancy and embryo loss in pigs.

Identification of autophagy-associated circRNAs in sepsis-induced cardiomyopathy of mice

Circular RNAs (circRNAs) play a role in sepsis-related autophagy. However, the role of circRNAs in autophagy after sepsis-induced cardiomyopathy (SICM) is unknown, so we explored the circRNA expression profiles associated with autophagy in an acute sepsis mouse model. At a dose of 10 mg/kg, mice were intraperitoneally administered with lipopolysaccharides. The myocardial tissue was harvested after 6 h for microarray analysis, qRT-PCR, and western blotting. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes and Gene Set Enrichment Analysis were evaluated, and a competing endogenous RNA network was constructed, to evaluate the role of circRNAs related to autophagy in SICM. In total, 1,735 differently expressed circRNAs were identified in the LPS-treated group, including 990 upregulated and 745 downregulated circRNAs. The expression level of the autophagy-specific protein p62 decreased, while the ratio of LC3 II to LC3 I increased. Additionally, 309 mRNAs and 187 circRNAs were correlated with autophagy in myocardial tissue after SICM. Of these, 179 circRNAs were predicted to function as “miRNA sponges”. Some distinctive circRNAs and mRNAs found by ceRNA analysis might be involved in autophagy in SICM. These findings provide insights into circRNAs and identified new research targets that may be used to further explore the pathogenesis of SICM.

LncRNA activates immune response against Vibrio anguillarum in the intestine-liver axis of turbot (Scophthalmus maximus L.) by sponging miRNA in a ceRNA regulatory network

Vibriosis, most commonly caused by the bacterium Vibrio anguillarum, is one of the most important diseases affecting the marine aquaculture industry throughout the world. The intestine is the main entry portal of V. anguillarum into host fishes. Although there has been extensive research on the immunity of the gut-associated lymphoid tissue (GALT) in teleost, the mechanisms underlying the immunity of the intestine-liver during bacterial infections are still not well understood. This study conducted an integrative analysis of the transcriptome in turbot (Scopthalmus maximus L.) intestine and liver after V. anguillarum infection. To provide evidence of immunological collaboration in the turbot intestine-liver axis, we constructed the immune gene libraries, and conducted the functional annotation and enrichment analyses of immune genes that were jointly expressed in both turbot intestine and liver. Additionally, we administered the bioinformatic analyses of transcriptomic data to investigate regulatory relationships between non-coding RNAs (ncRNAs) and their target immune genes, based on the ceRNA theory. The recognition and binding abilities to bacteria were activated by the Toll-like receptor (TLR) signaling pathway. Subsequently, NF-κB was activated by the TLR/MyD88 signaling, and its target genes were induced to up-regulate in intestine and associated tissues to the digestive tract to enhance disease resistance through the production of inflammation. Histology of the intestine and liver of infected fish showed pathological changes consistent with inflammation. Bioinformatic analysis suggested that ceRNA regulatory networks play a pivotal role in the regulation of TLR genes, and RT-qPCR analyses and dual-luciferase reporter assays showed confirmed evidence to verify these hypothesized regulatory relationships. Overall, the results in this study demonstrated that a lncRNA (LNC_002468) activated the TLR signaling pathway by upregulating the TLR9 gene through sponging miRNA (novel_709). This study provides a strong indication that ncRNAs play regulatory roles in the antibacterial immune response of teleost fishes. However, further functional verification is required of the key immune genes and their regulatory relationship with miRNAs and lncRNAs.

A novel CircRNA Circ_0001722 regulates proliferation and invasion of osteosarcoma cells through targeting miR-204-5p/RUNX2 axis

BackgroundOsteosarcoma (OS) is the most prevalent primary fatal bone neoplasm in adolescents and children owing to limited therapeutic methods. Circular RNAs (circRNAs) are identified as vital regulators in a variety of cancers. However, the roles of circRNAs in OS are still unclear.MethodsFirstly, we evaluate the differentially expressed circRNAs in 3 paired OS and corresponding adjacent nontumor tissue samples by circRNA microarray assay, finding a novel circRNA, circ_001722, significantly upregulated in OS tissues and cells. The circular structure of candidate circRNA was confirmed through Sanger sequencing, divergent primer PCR, and RNase R treatments. Proliferation of OS cells was evaluated in vitro and in vivo. The microRNA (miRNA) sponge mechanism of circRNAs was verified by dual-luciferase assay and RNA immunoprecipitation assay.ResultsA novel circRNA, circ_001722, is significantly upregulated in OS tissues and cells. Downregulation of circ_0001722 can suppress proliferation and invasion of human OS cells in vitro and in vivo. Computational algorithms predict miR-204-5p can bind with circ_0001722 and RUNX2 mRNA 3’UTR, which is verified by Dual-luciferase assay and RNA immunoprecipitation assay. Further functional experiments show that circ_0001722 competitively binds to miR-204-5p and prevents it to decrease the level of RUNX2, which upregulates proliferation and invasion of human OS cells.ConclusionCirc_001722 is a novel tumor promotor in OS, and promotes the progression of OS via miR-204-5p/RUNX2 axis.

CircDOCK7 facilitates the proliferation and adipogenic differentiation of chicken abdominal preadipocytes through the gga-miR-301b-3p/ACSL1 axis

BackgroundAbdominal fat deposition depends on both the proliferation of preadipocytes and their maturation into adipocytes, which is a well-orchestrated multistep process involving many regulatory molecules. Circular RNAs (circRNAs) have emergingly been implicated in mammalian adipogenesis. However, circRNA-mediated regulation in chicken adipogenesis remains unclear. Our previous circRNA sequencing data identified a differentially expressed novel circRNA, 8:27,886,180|27,889,657, during the adipogenic differentiation of chicken abdominal preadipocytes. This study aimed to investigate the regulatory role of circDOCK7 in the proliferation and adipogenic differentiation of chicken abdominal preadipocytes, and explore its molecular mechanisms of competing endogenous RNA underlying chicken adipogenesis.ResultsOur results showed that 8:27,886,180|27,889,657 is an exonic circRNA derived from the head-to-tail splicing of exons 19–22 of the dedicator of cytokinesis 7 (DOCK7) gene, abbreviated as circDOCK7. CircDOCK7 is mainly distributed in the cytoplasm of chicken abdominal preadipocytes and is stable because of its RNase R resistance and longer half-life. CircDOCK7 is significantly upregulated in the abdominal fat tissues of fat chickens compared to lean chickens, and its expression gradually increases during the proliferation and adipogenic differentiation of chicken abdominal preadipocytes. Functionally, the gain- and loss-of-function experiments showed that circDOCK7 promoted proliferation, G0/G1- to S-phase progression, and glucose uptake capacity of chicken abdominal preadipocytes, in parallel with adipogenic differentiation characterized by remarkably increased intracellular lipid droplet accumulation and triglyceride and acetyl coenzyme A content in differentiated chicken abdominal preadipocytes. Mechanistically, a pull-down assay and a dual-luciferase reporter assay confirmed that circDOCK7 interacted with gga-miR-301b-3p, which was identified as an inhibitor of chicken abdominal adipogenesis. Moreover, the ACSL1 gene was demonstrated to be a direct target of gga-miR-301b-3p. Chicken ACSL1 protein is localized in the endoplasmic reticulum and mitochondria of chicken abdominal preadipocytes and acts as an adipogenesis accelerator. Rescue experiments showed that circDOCK7 could counteract the inhibitory effects of gga-miR-301b-3p on ACSL1 mRNA abundance as well as the proliferation and adipogenic differentiation of chicken abdominal preadipocytes.ConclusionsCircDOCK7 serves as a miRNA sponge that directly sequesters gga-miR-301b-3p away from the ACSL1 gene, thus augmenting adipogenesis in chickens. These findings may elucidate a new regulatory mechanism underlying abdominal fat deposition in chickens.

Construction of lncRNA- and circRNA-associated ceRNA networks in the prostatic urethra of rats after simulating transurethral laser prostatectomy (TULP)

Non-coding RNA appears to be involved in wound repair. Competing endogenous RNA (ceRNA) appears to be an important post-transcriptional mechanism, it means that long noncoding RNA (lncRNA) or circular RNA (circRNA) acts as a microRNA (miRNA) sponge to further regulate mRNA. However, ceRNA network related to wound repair after prostatectomy has yet been constructed. TULP is the main surgical method of prostatectomy, but there have been no reports of TULP rat models in the past. We simulated TULP on rats, and observed the whole process of wound injury and repair after operation through pathological examination of wound tissue. Next, we discovered 732 differentially expressed lncRNAs (DElncRNAs), 47 differentially expressed circRNAs (DEcircRNAs), 17 differentially expressed miRNAs (DEmiRNAs), and 1892 differentially expressed mRNAs (DEmRNAs) related to wound repair after TULP through full transcriptome microarray and bioinformatics methods, and confirmed the reliability of transcriptome data by quantitative Reverse Transcription PCR (qRT-PCR), and immunohistochemistry. Then, we constructed the lncRNA- and circRNA-associated ceRNA regulatory networks related to wound repair after TULP in rats. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that molecules in these networks were mainly involved in inflammatory infiltration, cell differentiation, and intercellular interactions and involved signal pathways such as the PI3K-Akt signaling pathway. Thus, this study successfully established the TULP model in rats, revealed potentially important biomarkers and ceRNA networks after prostatectomy in rats, and provided theoretical support for the repair of post-prostatectomy wound.

Functions of Circular RNA in Human Diseases and Illnesses.

Circular RNAs (circRNAs) represent single-stranded RNA species that contain covalently closed 3' and 5' ends that provide them more stability than linear RNA, which has free ends. Emerging evidence indicates that circRNAs perform essential functions in many DNA viruses, including coronaviruses, Epstein-Barr viruses, cytomegalovirus, and Kaposi sarcoma viruses. Recent studies have confirmed that circRNAs are present in viruses, including DNA and RNA viruses, and play various important functions such as evading host immune response, disease pathogenesis, protein translation, miRNA sponges, regulating cell proliferation, and virus replication. Studies have confirmed that circRNAs can be biological signatures or pathological markers for autoimmune diseases, neurological diseases, and cancers. However, our understanding of circRNAs in DNA and RNA viruses is still limited, and functional evaluation of viral and host circRNAs is essential to completely understand their biological functions. In the present review, we describe the metabolism and cellular roles of circRNA, including its roles in various diseases and viral and cellular circRNA functions. Circular RNAs are found to interact with RNA, proteins, and DNA, and thus can modulate cellular processes, including translation, transcription, splicing, and other functions. Circular RNAs interfere with various signaling pathways and take part in vital functions in various biological, physiological, cellular, and pathophysiological processes. We also summarize recent evidence demonstrating cellular and viral circRNA's roles in DNA and RNA viruses in this growing field of research.

Expression Profile and Regulatory Properties of m6A-Modified circRNAs in the Longissimus Dorsi of Queshan Black and Large White Pigs.

It is well known that N6-methyladenosine (m6A) is the most abundant modification in linear RNA molecules, but many circRNA molecules have now been found to have a wide range of m6A modification sites as well. However, there are few relevant studies and information on the expression profile and functional regulatory properties of m6A-modified circRNAs (m6A-circRNAs) in longissimus dorsi. In this study, a total of 12 putative m6A-circRNAs were identified and characterized in the longissimus dorsi of Queshan Black and Large White pigs-8 of them were significantly more expressed in the longissimus dorsi of Queshan Black than in Large White pigs, while the other 4 were the opposite. These 12 putative m6A-circRNAs were also found to act as miRNA sponge molecules to regulate fat deposition by constructing the ceRNA regulatory network. Enrichment analysis also revealed that the 12 m6A-circRNAs parent genes and their adsorbed miRNA target genes were widely involved in fat deposition and cell proliferation and differentiation-related pathways, such as the HIF-1 signaling pathway, the pentose phosphate pathway, the MAPK signaling pathway, the glycosphingolipid biosynthesis-lacto and neolacto series, and the TNF signaling pathway, suggesting that the analyzed m6A-circRNAs may be largely involved in the formation of pork quality. These results provide new information to study the regulatory properties of m6A-circRNAs in the formation of pork quality.

Downregulation of circular RNA hsa_circ_0087856 sensitizes bladder cancer cells to cisplatin through targeting miR-1184/CITED2 signaling.

CircRNAs are considered as one of the potential therapeutic targets of multiple cancers. According to accumulating evidence, circRNA regulates cancer progression by acting as a miRNA sponge. In the current work, our data discovered that hsa_circ_0087856 and CITED2 expression was increased, while miR-1184 expression was decreased in BC cell lines and tissues. Hsa_circ_0087856 expression negatively correlated with miR-1184, whereas positively correlated with CITED2. Hsa_circ_0087856 silencing suppressed BC tumor growth, and contributed to the inhibition of cisplatin to tumor growth. In cellular experiments, hsa_circ_0087856 increasing promoted BC cells proliferation, migration and invasion, and inhibited the cells apoptosis. Hsa_circ_0087856 increasing partly reversed the inhibition of cisplatin to BC cell proliferation and the promotion to cell apoptosis. Oppositely, hsa_circ_0087856 silencing could increase the sensitivity of BC cells to cisplatin. Hsa_circ_0087856 promoted CITED2 expression through binding with miR-1184 and inhibiting its expression. CITED2 increasing partly reversed the promotion of hsa_circ_0087856 silencing to cisplatin-induced BC cells apoptosis promotion and proliferation suppression. Overall, our results revealed the role of hsa_circ_0087856 that downregulation its expression could enhance the BC cells sensitivity to cisplatin by facilitating CITED expression via sponging miR-1184. Moreover, our research provided a potential therapeutic target for BC. This article is protected by copyright. All rights reserved.

Exosome-delivered circRPS5 inhibits the progression of melanoma via regulating the miR-151a/NPTX1 axis.

Circular RNAs (circRNAs) have been reported to exert critical functions in tumorigenesis and development. However, the underlying mechanism by which circRNAs regulate melanoma progression remain to be elucidated. The differentially expressed circRNAs were first identified by circRNA-seq, and circRNAs were validated via qRT-PCR and Sanger sequencing. Then, the impact of circRPS5, miR-151a and NPTX1 expression on the progression of melanoma cell were determined by gain- and loss-of-function assays. The relationship between circRPS5, miR-151a, and NPTX1 was predicted by StarBase website and authenticated by luciferase reporter assay. The melanoma cells-derived exosomes were characterized using nanoparticle tracking analysis (NTA) and western blot. CircRPS5 was significantly downregulated in melanoma tissues and cell lines. Functionally, circRPS5 suppressed the proliferation, migration, and invasion of melanoma cells, and induced cell cycle arrest and apoptosis in vitro. Mechanistically, circRPS5 harbor miR-151a, acting as miRNA sponge, and then miR-151a targeted the 3'-UTR of NPTX1. Finally, circRPS5 was mainly incorporated into exosomes to inhibit the progression of melanoma cells. This finding reveal circRPS5 suppressed the progression of melanoma through miR-151a/NPTX1 pathway, and may provide a promising therapeutic strategies for melanoma.

The Biological Role and Translational Implications of the Long Non-Coding RNA GAS5 in Breast Cancer.

The lncRNA GAS5 plays a significant role in tumorigenicity and progression of breast cancer (BC). In this review, we first summarize the role of GAS5 in cell biology, focusing on its expression data in human normal tissues. We present data on GAS5 expression in human BC tissues, highlighting its downregulation in all major BC classes. The main findings regarding the molecular mechanisms underlying GAS5 dysregulation are discussed, including DNA hypermethylation of the CpG island located in the promoter region of the gene. We focused on the action of GAS5 as a miRNA sponge, which is able to sequester microRNAs and modulate the expression levels of their mRNA targets, particularly those involved in cell invasion, apoptosis, and drug response. In the second part, we highlight the translational implications of GAS5 in BC. We discuss the current knowledge on the role of GAS5 as candidate prognostic factor, a responsive molecular therapeutic target, and a circulating biomarker in liquid biopsies with clinical importance in BC. The findings position GAS5 as a promising druggable biomolecule and stimulate the development of strategies to restore its expression levels for novel therapeutic approaches that could benefit BC patients in the future.

Genome wide identification and characterization of fertility associated novel CircRNAs as ceRNA reveal their regulatory roles in sheep fecundity

Reproductive traits play a vital role in determining the production efficiency of sheep. Maximizing the production is of paramount importance for breeders worldwide due to the growing population. Circular RNAs (circRNAs) act as miRNA sponges by absorbing miRNA activity through miRNA response elements (MREs) and participate in ceRNA regulatory networks (ceRNETs) to regulate mRNA expression. Despite of extensive research on role of circRNAs as miRNA sponges in various species, their specific regulatory roles and mechanism in sheep ovarian tissue are still not well understood. In this study, we performed whole genome sequencing of circRNAs, miRNA and mRNA employing bioinformatic techniques on ovine tissues of two contrasting sheep breeds "Small tail Han (X_LC) and Dolang sheep (D_LC)", which results into identification of 9,878 circRNAs with a total length of 23,522,667 nt and an average length of 2,381.32 nt. Among them, 44 differentially expressed circRNAs (DECs) were identified. Moreover, correlation between miRNA-mRNA and lncRNA-miRNA provided us with to prediction of miRNA binding sites on nine differentially expressed circRNAs and 165 differentially expressed mRNAs using miRanda. miRNA-mRNA and lncRNA-miRNA pairs with negative correlation were selected to determine the ceRNA score along with positively correlated pairs from lncRNA and mRNA network. Integration of ceRNA score and positively correlated pairs exhibit a significant ternary relationship among circRNAs-miRNA-mRNA demonestrated by ceRNA, comprising of 50 regulatory pairs sharring common nodes and predicted potential differentially expressed circRNAs-miRNAs-mRNAs regulatory axis. Based on functional enrichment analysis shortlisted key ceRNA regulatory pairs associated with reproduction including circRNA_3257-novel579_mature-EPHA3, circRNA_8396-novel130_mature-LOC101102473, circRNA_4140- novel34_mature > novel661_mature-KCNK9, and circRNA_8312-novel339_mature-LOC101110545. Furthermore, expression profiling, functional enrichments and qRT-PCR analysis of key target genes infer their implication in reproduction and metabolism. ceRNA target mRNAs evolutionary trajectories, expression profiling, functional enrichments, subcellular localizations following genomic organizations will provide new insights underlying molecular mechanisms of reproduction, and establish a solid foundation for future research.Graphical Graphical abstract summarizing the scheme of study