Circular RNAs (circRNAs) are a new class of non-coding RNAs, which have been confirmed to regulate insect gene expression and immune response through multiple manners such as competing endogenous RNA (ceRNA) regulatory network. Currently, function of circRNA in honey bee immune response remains unclear. In this study, PCR and Sanger sequencing were performed to validate the back splicing (BS) site of ame_circ_000115 (in short ac115). RT-qPCR was used to detect the expression profile of ac115 in larval guts of Apis mellifera ligustica stressed by Ascosphaera apis. Dual-luciferase reporter gene assay was conducted to verify the binding relationship between ac115 and ame-miR-13b. Interference of ac115 in larval guts was carried out by feeding specific siRNA, followed by determination of the effect of ac115 interference on expression of six genes relevant to host immune response. The results confirmed the existence of BS site within ac115. Compared with the un-inoculated group, the expression of ac115 in 4-day-old larval gut of the A. apis-inoculated group was up-regulated with extreme significance (P < 0.000 1), while that in 5- and 6-day-old larval guts were significantly up-regulated (P < 0.05). The brightness of specific band for ac115 in 4-, 5- and 6-day-old larval guts of the siRNA-circ_000115-fed group gradually became weak, whereas that of the siRNA-scrambl-fed group was pretty high without obvious variation. Compared with that of the siRNA-scramble-fed group, the expression of ac115 in 4-day-old larval gut of the siRNA-circ_000115-fed group was significantly down-regulated (P < 0.05), whereas that of the 5- and 6-day-old larval guts were down-regulated with extreme significance (P < 0.001). Ame-miR-13b was truly existed and expressed in A. m. ligustica larval guts, and there was true binding relationship between ac115 and ame-miR-13b. Compared with that of the siRNA-scramble-fed group, the expression of antimicrobial peptide genes hymenoptaecin and abaecin in 6-day-old larval gut of the siRNA-circ_000115-fed group was significantly up-regulated (P < 0.05), while that of ecdysone receptor (Ecr) was down-regulated with extreme significance (P < 0.01). These results indicate that ac115 is truly expressed in A. m. ligustica larval guts, BS site truly exists within ac115, and effective interference of ac115 in A. m. ligustica larval guts can be achieved via feeding siRNA. Moreover, ac115 potentially regulates Ecr expression through adsorption of ame-miR-13b and expression of hymenoptaecin and abaecin using a non-ceRNA manner, further participating in host stress-response.
Bees/genetics* ; Animals ; Larva/metabolism* ; RNA, Circular/genetics* ; RNA, Small Interfering/genetics* ; MicroRNAs/genetics*

Non-coding RNAs (ncRNAs) are a class of functional RNAs that play critical roles in different diseases. NcRNAs include microRNAs, long ncRNAs, and circular RNAs. They are highly expressed in the brain and are involved in the regulation of physiological and pathophysiological processes of central nervous system (CNS) diseases. Mounting evidence indicates that ncRNAs play key roles in CNS diseases. Further elucidating the mechanisms of ncRNA underlying the process of regulating glial function that may lead to the identification of novel therapeutic targets for CNS diseases.
Humans ; RNA, Untranslated/genetics* ; MicroRNAs/genetics* ; RNA, Long Noncoding/genetics* ; RNA, Circular ; Central Nervous System Diseases/genetics*

Parasite-derived non-coding RNAs (ncRNAs) not only contribute to life activities of parasites, and microRNA (miRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA) may generate a competitive endogenous RNA (ceRNA) regulatory network with host miRNAs and mRNAs via extracellular vesicles, thereby participating in infection and pathogenic processes. This article presents an overview of characterizing ncRNAs derived from parasites and the cross-species regulatory role of parasite-derived ncRNAs in host gene expression and its underlying mechanisms.
Animals ; Parasites ; Gene Regulatory Networks ; MicroRNAs/metabolism* ; RNA, Messenger/genetics* ; RNA, Circular/genetics* ; RNA, Competitive Endogenous

Most hematological tumors have high-grade malignancy and low cure rate, requiring new molecular markers for detection and evaluation. Circular RNAs (circRNAs) are a class of non-coding RNAs with covalently closed-loop structures, which participate in gene transcription and translation by binding to microRNAs and proteins. In recent years, with the deepening research on circRNAs, circRNAs have been found to play an important role in hematological malignancies. In this review, the latest research progress on the function and molecular mechanism of circRNAs in hematological malignancies was systematically summarized, and it was found that circRNAs may be potential new biomarkers and therapeutic targets in hematological malignancies.
Humans ; RNA, Circular ; MicroRNAs/genetics* ; Neoplasms ; Hematologic Neoplasms/genetics* ; Biomarkers

OBJECTIVE: To identify and characterize read-through RNAs and read-through circular RNAs (rt-circ-HS) derived from transcriptional read-through hypoxia inducible factor 1α (HIF1α) and small nuclear RNA activating complex polypeptide 1 (SNAPC1) the two adjacent genes located on chromosome 14q23, in renal carcinoma cells and renal carcinoma tissues, and to study the effects of rt-circ-HS on biological behavior of renal carcinoma cells and on regulation of HIF1α. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) and Sanger sequencing were used to examine expression of read-through RNAs HIF1α-SNAPC1 and rt-circ-HS in different tumor cells. Tissue microarrays of 437 different types of renal cell carcinoma (RCC) were constructed, and chromogenic in situ hybridization (ISH) was used to investigate expression of rt-circ-HS in different RCC types. Small interference RNA (siRNA) and artificial overexpression plasmids were designed to examine the effects of rt-circ-HS on 786-O and A498 renal carcinoma cell proliferation, migration and invasiveness by cell counting kit 8 (CCK8), EdU incorporation and Transwell cell migration and invasion assays. RT-PCR and Western blot were used to exa-mine expression of HIF1α and SNAPC1 RNA and proteins after interference of rt-circ-HS with siRNA, respectively. The binding of rt-circ-HS with microRNA 539 (miR-539), and miR-539 with HIF1α 3' untranslated region (3' UTR), and the effects of these interactions were investigated by dual luciferase reporter gene assays. RESULTS: We discovered a novel 1 144 nt rt-circ-HS, which was derived from read-through RNA HIF1α-SNAPC1 and consisted of HIF1α exon 2-6 and SNAPC1 exon 2-4. Expression of rt-circ-HS was significantly upregulated in 786-O renal carcinoma cells. ISH showed that the overall positive expression rate of rt-circ-HS in RCC tissue samples was 67.5% (295/437), and the expression was different in different types of RCCs. Mechanistically, rt-circ-HS promoted renal carcinoma cell proliferation, migration and invasiveness by functioning as a competitive endogenous inhibitor of miR-539, which we found to be a potent post-transcriptional suppressor of HIF1α, thus promoting expression of HIF1α. CONCLUSION The novel rt-circ-HS is highly expressed in different types of RCCs and acts as a competitive endogenous inhibitor of miR-539 to promote expression of its parental gene HIF1α and thus the proliferation, migration and invasion of renal cancer cells.
Humans ; Carcinoma, Renal Cell/pathology* ; Cell Proliferation ; Hypoxia ; Kidney Neoplasms ; MicroRNAs/genetics* ; Neoplasm Invasiveness/genetics* ; RNA, Circular/metabolism* ; RNA, Small Interfering ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics*

OBJECTIVE: To investigate the effect of titanium dioxide nanoparticles (TiO₂ NPs) on the expression profile of circular ribonucleic acid (circRNA) in human hepatocytes through in vitro cell experiments, and to attempt to understand the potential mechanism of hepatotoxicity through bioinformatics analysis. METHODS: TiO₂ NPs were characterized from the aspects of particle size, shape and agglomeration state. The cell counting kit-8 (CCK8) was used to detect the cytotoxicity of TiO₂ NPs against human hepatocellular carcinoma cells (HepG2) after exposure to 0, 1.56, 3.13, 6.25, 12.5, 25, 50, 100, and 200 mg/L TiO₂ NPs for 24 h or 48 h. The cells were treated at doses of 0 mg/L TiO₂ NPs (control group) and 100 mg/L TiO₂ NPs (treatment group), and collected after exposure for 48 h, and then RNA from the extracted cell samples was collected and sequenced. The differential circRNAs between the control and the TiO₂ NPs treatment groups were screened, and then the enrichment pathway of the differential circRNA target gene was analyzed by multivariate statistics. According to the sequencing results, significantly altered genes and important genes in the significant enrichment pathways were screened, and real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) was performed to verify the results. RESULTS: TiO₂ NPs were spherical anatase with a hydrated particle size of (323.50±85.44) nm and a Zeta potential of (-21.00±0.72) mV in a serum-free medium. The results of the CCK8 cytotoxicity assay showed that with the increase of TiO₂ NPs concentration, cell viability gradually decreased. A total of 11 478 circRNAs were found by RNA sequencing. Compared with the control groups, TiO₂ NPs treatment groups (100 mg/L) had a total of 89 differential circRNAs, of which 59 were up-regulated and 30 were down-regulated. Analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway showed that the targeted genes of differential circRNAs were mainly enriched in fatty acid degradation, Fanconi anemia pathway, and fatty acid metabolism. The expression levels of circRNA.6730, circRNA.3650 and circRNA.4321 were significantly different between the TiO₂ NPs treatment group and the control group, which were consistent with the sequencing results. CONCLUSION TiO₂ NPs can induce changes in circRNA expression profile, and epigenetics may play an important role in the mechanism of hepatotoxicity.
Humans ; RNA/genetics* ; RNA, Circular/genetics* ; Carcinoma, Hepatocellular/genetics* ; Liver Neoplasms/genetics* ; Titanium ; Nanoparticles ; Chemical and Drug Induced Liver Injury ; Fatty Acids

OBJECTIVE: To screen for differentially expressed circular RNAs (circRNAs) in the serum of preterm infants with intraventricular hemorrhage (IVH) and explore the competitive endogenous RNA (ceRNA) mechanism of circRNAs in IVH in these infants. METHODS: Fifty preterm infants (gestational age of 28 to 34 weeks) admitted in our department between January, 2019 and January, 2020 were enrolled in this study, including 25 with a MRI diagnosis of IVH and 25 without IVH. Serum samples were collected from 3 randomly selected infants from each group for profiling differentially expressed circRNAs using circRNA array technique. Gene ontology (GO) and pathway analyses were performed to reveal the function of the identified circRNAs. The circRNA-miRNA-mRNA network was constructed to identify the co-expression network of hsa_circ_ 0087893. RESULTS: A total of 121 differentially expressed circRNAs were identified in the infants with IVH, including 62 up-regulated and 59 down-regulated circRNAs. GO and pathway analyses showed that these circRNAs were involved in multiple biological processes and pathways, including cell proliferation, activation and death, DNA damage and repair, retinol metabolism, sphingolipid metabolism, cell adhesion molecules. Among these circRNAs, hsa_circ_0087893 was found to have significant down-regulation in IVH group and co-express with 41 miRNAs and 15 mRNAs (such as miR-214-3p, miR-761, miR-183-5p, AKR1B1, KRT34, PPP2CB, and HPRT1). CONCLUSION The circRNA hsa_circ_0087893 may function as a ceRNA and play an important role in the occurrence and progression of IVH in preterm infants.
Infant, Newborn ; Infant ; Humans ; RNA, Circular ; Infant, Premature ; MicroRNAs ; RNA, Messenger ; Cerebral Hemorrhage/genetics* ; Aldehyde Reductase

OBJECTIVES: To investigate the role and mechanism of circRNA-SR-related CTD associated factor 8 (SCAF8) in regulating endothelial cell pyroptosis in high glucose environment. METHODS: Human umbilical vein endothelial cells (HUVECs) were cultured and divided into six groups. The normal control group and high glucose control group were cultured in cell culture medium with 5 and 33 mmol/L glucose, respectively. The RNA control group, circRNA-SCAF8 inhibition group, miR-93-5p overexpression group and miR-93-5p inhibition group were added with non-functional siRNA, circRNA-SCAF8 inhibitor, miR-93-5p overexpression molecule and miR-93-5p inhibitor in high glucose environment, respectively. Cell viability and pyroptosis were detected by cell counting kit-8 (CCK-8) assay, flow cytometry and Hoechst 33342/propidium iodide fluorescence double staining. Western blotting and enzyme-linked immunosorbent assay were used to detect the expression of pyroptosis-related factors including apoptosis-associated speck-like protein containing a CARD (ASC), cysteine aspartic acid specific protease-1 (caspase-1) and Gasdermin D (GSDMD), NOD like receptor protein 3 (NLRP-3), thioredoxin interacting proteins (TXNIP), IL-18 and IL-1β. The expression of circRNA-SCAF8, miR-93-5p and TXNIP was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Fluorescence in situ hybridization (FISH) was used to locate circRNA-SCAF8 and miR-93-5p. Dual luciferase assay was used to verify the targeted regulatory relationship between miR-93-5p and upstream and downstream molecules. RESULTS: Compared with the RNA control group, the cell survival rate of circRNA-SCAF8 inhibition group and miR-93-5p overexpression group increased (both P<0.01), the pyroptosis decreased (both P<0.01), and the expressions of pyroptosis-related factors such as TXNIP, NLRP-3, caspase-1, GSDMD, ASC, IL-18 and IL-1β were significantly decreased (all P<0.05). The expression of miR-93-5p was significantly increased after inhibition of circRNA-SCAF8 (P<0.01), and the expression of circRNA-SCAF8 tended to decrease after overexpression of miR-93-5p, but with no statistical significance (P>0.05). Dual luciferase assay showed that miR-93-5p downre-gulated circRNA-SCAF8 expression by binding to the 3 ´ UTR region of circRNA-SCAF8, and miR-93-5p downregulated TXNIP expression by binding to the 3 ´ UTR region of TXNIP. FISH showed that circRNA-SCAF8 and miR-93-5p were both located in the cytoplasm and were highly associated in the cells. qRT-PCR showed that the relative expression of TXNIP increased or decreased after overexpression or inhibition of miR-93-5p compared with the RNA control group, respectively (both P<0.05), suggesting that miR-93-5p could regulate TXNIP gene expression. CONCLUSIONS CircRNA-SCAF8/miR-93-5p/TXNIP axis is involved in the regulation of pyroptosis in HUVECs under high glucose.
Humans ; Factor VIII ; RNA, Circular ; Endothelial Cells ; Interleukin-18 ; Pyroptosis ; In Situ Hybridization, Fluorescence ; Caspase 1 ; MicroRNAs/genetics* ; Carrier Proteins/genetics* ; RNA-Binding Proteins

OBJECTIVE: To explore the effects and molecular mechanism of circ-SFMBT2 on the proliferation, migration and invasion of acute myeloid leukemia (AML) cells. METHODS: Bone marrow samples from 35 pediatric AML patients and 35 healthy controls in Henan Provincial Children's Hospital from April 2015 to April 2017 and human bone marrow stromal cell lines (HS-5) and AML cell lines (HL-60, THP-1, U-937 and Kasumi-1) were collected. The expressions of circ-SFMBT2, miR-491-5p and homeobox A9 (HOXA9) in bone marrow samples and cells were detected by RT-qPCR and Western blot. The Pearson method was used to analyze the correlation of circ-SFMBT2, miR-491-5p and HOXA9 mRNA expression levels in bone marrow samples of AML patients. HL-60 cells were cultured in vitro and divided into 5 groups: Control, si-NC, si-circ-SFMBT2, si-circ-SFMBT2+anti-NC and si-circ-SFMBT2+anti-miR-491-5p, HL-60 cells were transfected with si-NC, si-circ-SFMBT2, anti-NC, and miR-491-5p inhibitor with Lipofectamine™ 3000. RT-qPCR and Western blot were performed to detect the expression levels of circ-SFMBT2, miR-491-5p and HOXA9 in cells of each group. The proliferation activity of HL-60 cells in each group was detected by CCK-8 assay at 24, 48 and 72 h after transfection, respectively. The apoptosis rate was detected by flow cytometry. The migration and invasion abilities of cells were detected by Transwell assay. The regulatory roles of circ-SFMBT2, miR-491-5p and HOXA9 in AML cells were verified by dual-luciferase reporter gene assay, RNA pull-down and RNA-binding protein immunoprecipitation (RIP) experiments. RESULTS: The expression levels of circ-SFMBT2 and HOXA9 mRNA were increased in bone marrow samples and cell lines (HL-60, THP-1, U-937 and Kasumi-1) of children with AML (P <0.001), while the expression level of miR-491-5p was significantly decreased (P <0.001). Pearson correlation analysis showed that the expression levels of circ-SFMBT2 and miR-491-5p in bone marrow samples of AML children were negatively correlated (r =-0.905), miR-491-5p was also negatively correlated with HOXA9 mRNA (r =-0.930), while the expression levels of HOXA9 mRNA and circ-SFMBT2 was positively correlated (r =0.911). The overall survival rate of AML children with high expression of circ-SFMBT2 was significantly decreased than those with low expression of circ-SFMBT2 (P <0.05). Silencing of circ-SFMBT2 could greatly up-regulate the expression of miR-491-5p, decrease the expression of HOXA9, inhibit the proliferation, migration and invasion of AML cells, and promote cell apoptosis (P <0.05). Down-regulation of miR-491-5p expression greatly attenuated the inhibitory effects of circ-SFMBT2 silencing on cell proliferation, migration and invasion (P <0.05). Dual-luciferase reporter gene assay, RNA pull-down and RIP experiments confirmed that circ-SFMBT2 could target miR-491-5p and negatively regulate the expression of miR-491-5p in AML, and HOXA9 was the target of miR-491-5p. CONCLUSION Silencing of circ-SFMBT2 may inhibit the proliferation, migration and invasion of AML cells by regulating the miR-491-5p/HOXA9 axis.
Child ; Humans ; Cell Line, Tumor ; Cell Proliferation ; Genes, Homeobox ; HL-60 Cells ; Leukemia, Myeloid, Acute ; Luciferases ; MicroRNAs ; Repressor Proteins ; RNA, Messenger ; RNA, Circular/genetics*

Accumulating studies have demonstrated that non-coding RNAs (ncRNAs), functioning as important regulators of transcription and translation, are involved in the establishment and maintenance of pregnancy, especially the maternal immune adaptation process. The endometrial stromal cells (ESCs), trophoblast cells, and decidua immune cells that reside at the maternal-fetal interface are thought to play significant roles in normal pregnancy and pregnancy-associated diseases. Here, we reviewed the up-to-date evidence on how microRNA, long non-coding RNA, and circular RNA regulate ESCs, trophoblast cells, and immune cells and discussed the potential applications of these ncRNAs as diagnostic and therapeutic markers in pregnancy complications.
Pregnancy ; Female ; Humans ; MicroRNAs/genetics* ; RNA, Long Noncoding/genetics* ; RNA, Circular/genetics* ; Trophoblasts ; Pregnancy Complications/genetics*