CiRS-126 inhibits proliferation of ovarian granulosa cells through targeting the miR-21-PDCD4-ROS axis in a polycystic ovarian syndrome model

Circular RNA circRPS19 promotes chicken granulosa cell proliferation and steroid hormone synthesis by interrupting the miR-218-5p/INHBB axis

Ovarian follicle development is an important physiological activity for females and makes great significance in maintaining female health and reproduction performance. The development of ovarian follicle is mainly affected by the granulosa cells (GCs), whose growth is regulated by a variety of factors. Here, we identified a novel circular RNA (circRNA) derived from the Ribosomal protein S19 (RPS19) gene, named circRPS19, which is differentially expressed during chicken ovarian follicle development. Further explorations identified that circRPS19 promotes GCs proliferation and steroid hormone synthesis. Furthermore, circRPS19 was found to target and regulate miR-218-5p through a competitive manner with endogenous RNA (ceRNA). Functionals investigation revealed that miR-218-5p attenuates GCs proliferation and steroidogenesis, which is opposite to that of circRPS19. In addition, we also confirmed that circRPS19 upregulates the expression of Inhibin beta B subunit (INHBB) by binding with miR-218-5p to facilitate GCs proliferation and steroidogenesis. Overall, this study revealed that circRPS19 regulates GCs development by releasing the repression of miR-218-5p on INHBB, which suggests a novel mechanism in respect to circRNA and miRNA regulation in ovarian follicle development.

CircRNA_0026344 via miR-21 is involved in cigarette smoke-induced autophagy and apoptosis of alveolar epithelial cells in emphysema

Cigarette smoke (CS), a main source of indoor air pollution, is a primary risk factor for emphysema, and aberrant cellular autophagy is related to the pathogenesis of emphysema. Circular RNAs (circRNAs) affect the expression of mRNAs via acting as microRNA (miRNA) sponges, but their role in emphysema progression is not established. In the present investigation, CS, acting on alveolar epithelial cells, caused higher levels of miR-21, p-ERK, and cleaved-caspase 3 and led to lower levels of circRNA_0026344 and PTEN, which induced autophagy and apoptosis. miR-21 suppressed the expression of PTEN, which was involved in the regulation of autophagy and apoptosis. Further, in alveolar epithelial cells, overexpression of circRNA_0026344 blocked cigarette smoke extract (CSE)-induced autophagy and apoptosis, but this blockage was reversed by upregulation of miR-21 with a mimic. These results demonstrated that, in alveolar epithelial cells, CS decreases circRNA_0026344 levels, which sponge miR-21 to inhibit the miR-21 target, PTEN, which, in turn, activates ERK and thereby promotes autophagy and apoptosis, leading to emphysema. Thus, for emphysema, circRNA_0026344 regulates the PTEN/ERK axis by sponging miR-21, which is associated with the CS-induced autophagy and apoptosis of alveolar epithelial cells. In sum, the present investigation identifies a novel mechanism for CS-induced emphysema and provides information useful for the diagnosis and treatment of CS-induced emphysema.

Contribution of labor related gene subtype classification on heterogeneity of polycystic ovary syndrome

OBJECTIVE

As one of the most common endocrine disorders in women of reproductive age, polycystic ovary syndrome (PCOS) is highly heterogeneous with varied clinical features and diverse gestational complications among individuals. The patients with PCOS have 2-fold higher risk of preterm labor which is associated with substantial infant morbidity and mortality and great socioeconomic cost. The study was designated to identify molecular subtypes and the related hub genes to facilitate the susceptibility assessment of preterm labor in women with PCOS.

METHODS

Four mRNA datasets (GSE84958, GSE5090, GSE43264 and GSE98421) were obtained from Gene Expression Omnibus database. Twenty-eight candidate genes related to preterm labor or labor were yielded from the researches and our unpublished data. Then, we utilized unsupervised clustering to identify molecular subtypes in PCOS based on the expression of above candidate genes. Key modules were generated with weighted gene co-expression network analysis R package, and their hub genes were generated with CytoHubba. The probable biological function and mechanism were explored through Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis. In addition, STRING and Cytoscape software were used to identify the protein-protein interaction (PPI) network, and the molecular complex detection (MCODE) was used to identify the hub genes. Then the overlapping hub genes were predicted.

RESULTS

Two molecular subtypes were found in women with PCOS based on the expression similarity of preterm labor or labor-related genes, in which two modules were highlighted. The key modules and PPI network have five overlapping five hub genes, two of which, GTF2F2 and MYO6 gene, were further confirmed by the comparison between clustering subgroups according to the expression of hub genes.

CONCLUSIONS

Distinct PCOS molecular subtypes were identified with preterm labor or labor-related genes, which might uncover the potential mechanism underlying heterogeneity of clinical pregnancy complications in women with PCOS.

Genome-Wide Expression Profiling and Networking Reveals an Imperative Role of IMF-Associated Novel CircRNAs as ceRNA in Pigs

Intramuscular fat (IMF) deposition is a biological process that has a strong impact on the nutritional and sensorial properties of meat, with relevant consequences on human health. Pork loins determine the effects of marbling on the sensory attributes and meat quality properties, which differ among various pig breeds. This study explores the crosstalk of non-coding RNAs with mRNAs and analyzes the potential pathogenic role of IMF-associated competing endogenous RNA (ceRNA) in IMF tissues, which offer a framework for the functional validation of key/potential genes. A high-throughput whole-genome transcriptome analysis of IMF tissues from longissimus dorsi muscles of Large White (D_JN) and Laiwu (L_JN) pigs resulted in the identification of 283 differentially expressed circRNAs (DECs), including two key circRNAs (circRNA-23437, circRNA-08840) with potential binding sites for multiple miRNAs regulating the whole network. The potential ceRNA mechanism identified the DEC target miRNAs-mRNAs involved in lipid metabolism, fat deposition, meat quality, and metabolic syndrome via the circRNA-miRNA-mRNA network, concluding that ssc-mir-370 is the most important target miRNA shared by both key circRNAs. TGM2, SLC5A6, ECI1, FASN, PER1, SLC25A34, SOD1, and COL5A3 were identified as hub genes through an intensive protein-protein interaction (PPI) network analysis of target genes acquired from the ceRNA regulatory network. Functional enrichments, pathway examinations, and qRT-PCR analyses infer their implications in fat/cholesterol metabolism, insulin secretion, and fatty acid biosynthesis. Here, circRNAs and miRNA sequencing accompanied by computational techniques were performed to analyze their expressions in IMF tissues from the longissimus dorsi muscles of two pig breeds. Their target gene evolutionary trajectories, expression profiling, functional enrichments, subcellular localizations, and structural advances with high-throughput protein modeling, following genomic organizations, will provide new insights into the underlying molecular mechanisms of adipocyte differentiation and IMF deposition and a much-needed qualitative framework for future research to improve meat quality and its role as a biomarker to treat lipid metabolic syndromes.

Interplay Between Non-Coding RNAs and Programmed Cell Death Proteins

Programmed cell death (PDCD) family of proteins includes at least 12 members, function of seven of them being more investigated. These members are PDCD1, PDCD2, PDCD4, PDCD5, PDCD6, PDCD7 and PDCD10. Consistent with the important roles of these proteins in the regulation of apoptosis, dysregulation of PDCDs is associated with diverse disorders ranging from intervertebral disc degeneration, amyotrophic lateral sclerosis, immune thrombocytopenia, type 1 diabetes, congenital hypothyroidism, Alzheimer’s disease to different types of cancers. More recently, the interaction between non-coding RNAs and different members of PDCD family is being discovered. In the current study, we described the functional interactions between PDCDs and two classes of non-coding RNAs, namely microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). miR-21 and miR-183 are two miRNAs whose interactions with PDCDs have been assessed in different contexts. The lncRNAs interaction with PDCDs is mainly assessed in the context of neoplasia indicating the role of MALAT1, MEG3, SNHG14 and LINC00473 in this process.

Butylphthalide Inhibits TLR4/NF-κB Pathway by Upregulation of miR-21 to Have the Neuroprotective Effect

Stroke is a disease with the highest incidence rate and the highest mortality rate in the world. The study aims to verify the neuroprotective effect of Butylphthalide. The mice were divided into sham group, MCAO group, and MCAO + Butylphthalide-treated group. The mice in MCAO + Butylphthalide-treated group were administered with 70 mg/kg Butylphthalide injection intraperitoneally after cerebral ischemia-reperfusion. The normal saline with the same volume was administered intraperitoneally for the mice in the MCAO group and sham group. The levels of miR-21 in brain tissue and cells were detected by qPCR. The OGD/R injury model of Neuro2A cells was used to simulate the hypoxic-ischemic environment of neurons in vitro. The proliferation rate of Neuro2A cells was detected with CCK-8. The production of ROS was detected with DCFH-DA. Compared with the mice in MCAO group, a decrease (P < 0.01) was observed in the functional neurologic impairment scoring, cerebral infarction volume, and brain loss volume in the mice treated with MCAO + Butylphthalide, but an increase (P < 0.01) was observed in the level of miR-21, which was positively correlated with functional neurologic impairment scoring (r = -0.8933, P < 0.001). MTT assay showed that the cell viability of OGD/R + Butylphthalide group was significantly higher than that of other groups (P < 0.001), and the activity of ROS was significantly decreased (P < 0.001). The WB results showed that, compared with OGD/R + miR-NC and control groups, the ratio of Bcl-2/Bax in OGD/R + Butylphthalide group and OGD/R + miR-21 mimics group was significantly higher (P < 0.05), while the ratio of caspase-3/GAPDH was significantly lower (P < 0.05). In conclusion, Butylphthalide has neuroprotective effect on the mouse model of MCAO. It may upregulate the level of miR-21 to inhibit neuronal apoptosis and ROS production and improve the proliferation activity. The specific mechanism may lie in inhibiting TLR4/NF-κB pathway.

microRNAs and long non-coding RNAs as biomarkers for polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is known as the most common metabolic/endocrine disorder among women of reproductive age. Its complicated causality assessment and diagnostic emphasized the role of non‐coding regulatory RNAs as molecular biomarkers in studying, diagnosing and even as therapeutics of PCOS. This review discusses a comparative summary of research into microRNAs (miRNAs) and long non‐coding RNAs (lncRNAs) that are molecularly or statistically related to PCOS. We categorize the literature in terms of centering on either miRNAs or lncRNAs and discuss the combinatory studies and promising ideas as well. Additionally, we compare the pros and cons of the prominent research methodologies used for each of the abovementioned research themes and discuss how errors can be stopped from propagation by selecting correct methodologies for future research. Finally, it can be concluded that research into miRNAs and lncRNAs has the potential for identifying functional networks of regulation with multiple mRNAs (and hence, functional proteins). This new understanding may eventually afford clinicians to control the molecular course of the pathogenesis better. With further research, RNA (with statistical significance and present in the blood) may be used as biomarkers for the disease, and more possibilities for RNA therapy agents can be identified.

Circular RNA ciRs-126 promotes hypoxia/reoxygenation cardiac injury possibly through miR-21

Background

This study aimed to analyze the role of circular RNA ciRs-126 in hypoxia/reoxygenation cardiac injury (H/R).

Methods

Expression of ciRs-126 and miR-21 in plasma samples from patients with H/R and healthy controls was determined by RT-qPCR. Correlations were analyzed by linear regression. Overexpression of ciRs-126 and miR-21 was achieved in cardiomyocytes to explore their crosstalk. The roles of ciRs-126 and miR-21 in H/R-induced apoptosis of cardiomyocytes were analyzed using cell apoptosis assay.

Results

CiRs-126 was upregulated and miR-21 was downregulated in H/R patients. They were inversely correlated across plasma samples from H/R patients. In H/R cardiomyocytes, ciRs-126 was upregulated and miR-21 was downregulated. In cardiomyocytes, ciRs-126 overexpression decreased miR-21 level and reduced the inhibitory effects of miR-21 overexpression on H/R-induced cell apoptosis.

Conclusions

Circular RNA ciRs-126 may suppress miR-21 expression to promote H/R cardiac injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00355-x.

WGCNA Analysis Identifies Polycystic Ovary Syndrome-Associated Circular RNAs That Interact with RNA-Binding Proteins and Sponge miRNAs

Objective

Dysfunction of cumulus granulosa cells has been suggested as a contributor to abnormal folliculogenesis and the development of polycystic ovary syndrome (PCOS), but the underlying molecular mechanisms remain unclear. Recent studies indicate that circular RNAs (circRNAs) exert important roles for diseases. We aimed to screen crucial circRNAs of PCOS patients and predict their functions.

Methods

The high-throughput datasets of circRNAs (GSE145296), microRNAs (miRNAs; GSE72274) and messenger RNAs (mRNAs; GSE155489) in cumulus cells of PCOS patients and controls were collected from the Gene Expression Omnibus database. Differentially expressed circRNAs (DECs), miRNAs (DEMs) and protein-coding genes (DEGs) were identified by the limma method. The weighted correlation network analysis (WGCNA) was conducted using the DECs to mine PCOS-associated modules. Hub DECs in modules were defined as both of |gene significance| and |module membership| >0.8. The downstream effectors of hub DECs were predicted by constructing DEC-DEM-DEG ceRNA and DEC-RNA binding protein (RBP) networks. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to explore the functions of circRNAs.

Results

A total of 3614 DECs, 3544 DEGs and 1469 DEMs were identified between PCOS and controls. WGCNA analysis yielded five PCOS-related modules, of which 190 DECs were hub circRNAs. Seventeen hub DECs, nine DEMs, and 315 DEGs were identified to construct the ceRNA network, while 56 hub DECs and two DEGs (MBNL2, RBPMS) constituted the circRNA-RBP network. Five hub DECs (hsa_circ_0063309, hsa_circ_0054275, hsa_circ_0056196, hsa_circ_0018108 and hsa_circ_0070987) were overlapped between ceRNA and DEC-MBNL2 regulatory networks and thus they may be pivotal for PCOS. Furthermore, hsa_circ_0099109 could interact with the RBP gene RBPMS. Function analyses showed these circRNAs were inflammation-, apoptosis- or steroidogenesis-related.

Conclusion

Aberrant expression of six circRNAs that function as RBP regulators or miRNA sponges may be possible mechanisms underlying the pathogenesis of PCOS by affecting apoptosis and steroidogenesis in cumulus cells.

SNAI2-Induced CircMTO1 Promotes Cell Proliferation and Inhibits Apoptosis Through the miR-320b/MCL1 Axis in Human Granulosa-Like Tumor Cells

Polycystic ovary syndrome (PCOS), one of the most common types of endocrine diseases, is characterized by a high prevalence among women of reproductive-age. However, its pathogenesis and molecular mechanisms remain unclear. CircMTO1 has been reported to participate in numerous biological processes, but, its role in PCOS progression remains unknown. In the current study, we elucidated the expression and circRNA characterization of circMTO1 in human granulosa-like tumor cells. We found that circMTO1 knockdown promoted human granulosa-like tumor cell proliferation and inhibited its apoptosis rate. Next, we explored the underlying molecular mechanisms by using a series of experiments. Our results revealed the effect of the novel circMTO1/miR-320b/MCL1 axis in human granulosa-like tumor cells. Furthermore, we found that the expression of circMTO1 was induced by Snail family transcriptional repressor 2 (SNAI2) in human granulosa-like tumor cells. Our results may provide potential targets for PCOS research and a novel direction for the diagnosis and treatment of PCOS.

Pathogenetic analysis of polycystic ovary syndrome from the perspective of omics

Polycystic ovary syndrome (PCOS) is the most common gynecological endocrine disease, involving multiple genes, multiple pathways, and complex hormone secretion processes. Hence, the pathogenesis of PCOS cannot be explained by a single factor. Omics analysis includes genomics, transcriptomics, and proteomics, which are fast and effective methods for studying the pathogenesis of diseases. PCOS is primarily characterized by androgen excess, and reproductive and metabolic dysfunctions. The application of omics analysis in the body fluids, blood, cells or tissues of women with PCOS offers the potential for unexpected molecular advantages in explaining new mechanisms of PCOS etiology and pathophysiology, and provides new perspectives for identifying potential biomarkers and developing new therapeutic targets. At present, several omics analyses have been applied to produce complex datasets. In this manuscript, the recent advances in omics research on PCOS are summarized, aiming at an important and parallel review of the newly published research.

Construction of Circular RNA-MicroRNA-Messenger RNA Regulatory Network of Recurrent Implantation Failure to Explore Its Potential Pathogenesis

Background: Many studies on circular RNAs (circRNAs) have recently been published. However, the function of circRNAs in recurrent implantation failure (RIF) is unknown and remains to be explored. This study aims to determine the regulatory mechanisms of circRNAs in RIF.

Methods: Microarray data of RIF circRNA (GSE147442), microRNA (miRNA; GSE71332), and messenger RNA (mRNA; GSE103465) were downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed circRNA, miRNA, and mRNA. The circRNA–miRNA–mRNA network was constructed by Cytoscape 3.8.0 software, then the protein–protein interaction (PPI) network was constructed by STRING database, and the hub genes were identified by cytoHubba plug-in. The circRNA–miRNA–hub gene regulatory subnetwork was formed to understand the regulatory axis of hub genes in RIF. Finally, the Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the hub genes were performed by clusterProfiler package of Rstudio software, and Reactome Functional Interaction (FI) plug-in was used for reactome analysis to comprehensively analyze the mechanism of hub genes in RIF.

Results: A total of eight upregulated differentially expressed circRNAs (DECs), five downregulated DECs, 56 downregulated differentially expressed miRNAs (DEmiRs), 104 upregulated DEmiRs, 429 upregulated differentially expressed genes (DEGs), and 1,067 downregulated DEGs were identified regarding RIF. The miRNA response elements of 13 DECs were then predicted. Seven overlapping miRNAs were obtained by intersecting the predicted miRNA and DEmiRs. Then, 56 overlapping mRNAs were obtained by intersecting the predicted target mRNAs of seven miRNAs with 1,496 DEGs. The circRNA–miRNA–mRNA network and PPI network were constructed through six circRNAs, seven miRNAs, and 56 mRNAs; and four hub genes (YWHAZ, JAK2, MYH9, and RAP2C) were identified. The circRNA–miRNA–hub gene regulatory subnetwork with nine regulatory axes was formed in RIF. Functional enrichment analysis and reactome analysis showed that these four hub genes were closely related to the biological functions and pathways of RIF.

Conclusion: The results of this study provide further understanding of the potential pathogenesis from the perspective of circRNA-related competitive endogenous RNA network in RIF.

CircASPH promotes KGN cells proliferation through miR-375/MAP2K6 axis in Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS) is a kind of endocrine disorder which is prevalent in adult women, so exploring more biomarkers for PCOS is imperative. Recently, circular RNA and microRNA are confirmed to be related with PCOS development. Whether circular RNA ASPH (circASPH) is involved in PCOS need to be studied further. We utilized RT‐qPCR to measure the expression levels of circASPH, miR‐375 and MAP2K6 in PCOS patients and normal group. The effects of circASPH and miR‐375 on KGN cells proliferation and apoptosis were observed by CCK‐8 assay, EdU incorporation assay and apoptosis assay, separately. Then Dual‐luciferase reporter assay was carried out to verify the circASPH/miR375 axis and miR375/MAP2K6 axis. The interaction between circASPH and MAP2K6 were detected with the support of RT‐qPCR and Western blot. We found circASPH and MAP2K6 were both over‐expressed in PCOS patients, while miR‐375 was in the opposite direction. Moreover, miR‐375 was negatively regulated by circASPH, while MAP2K6 was positively regulated by circASPH. In addition, circASPH directly targeted miR‐375, which targeted MAP2K6. More than that, the knockdown of circASPH repressed KGN cells proliferation and enhanced apoptosis, while the silence of miR‐375 reversed the above effects. In conclusion, circASPH promotes KGN cells proliferation through miR‐375/MAP2K6 axis in PCOS, and they are thought‐provoking biomarkers for PCOS diagnosis and therapy.