Characterization of microRNA profile in human cumulus granulosa cells: Identification of microRNAs that regulate Notch signaling and are associated with PCOS

Target prediction and validation of microRNAs expressed from FSHR and aromatase genes in human ovarian granulosa cells

MicroRNAs (miRNAs) are known post-transcriptional regulators of various biological processes including ovarian follicle development. We have previously identified miRNAs from human pre-ovulatory ovarian granulosa cells that are expressed from the intronic regions of two key genes in normal follicular development: FSH receptor (FSHR) and CYP19A1, the latter encoding the aromatase enzyme. The present study aims to identify the target genes regulated by these miRNAs: hsa-miR-548ba and hsa-miR-7973, respectively. The miRNAs of interest were transfected into KGN cell line and the gene expression changes were analyzed by Affymetrix microarray. Potential miRNA-regulated genes were further filtered by bioinformatic target prediction algorithms and validated for direct miRNA:mRNA binding by luciferase reporter assay. LIFR, PTEN, NEO1 and SP110 were confirmed as targets for hsa-miR-548ba. Hsa-miR-7973 target genes ADAM19, PXDN and FMNL3 also passed all verification steps. Additionally, the expression pattern of the miRNAs was studied in human primary cumulus granulosa cell culture in relation to the expression of their host genes and FSH stimulation. Based on our findings we propose the involvement of hsa-miR-548ba in the regulation of follicle growth and activation via LIFR and PTEN. Hsa-miR-7973 may be implicated in the modulation of extracellular matrix and cell-cell interactions by regulating the expression of its identified targets.

The role of miRNAs in regulating adrenal and gonadal steroidogenesis

miRNAs are endogenous noncoding single-stranded small RNAs of ~22 nucleotides in length that post-transcriptionally repress the expression of their various target genes. They contribute to the regulation of a variety of physiologic processes including embryonic development, differentiation and proliferation, apoptosis, metabolism, hemostasis and inflammation. In addition, aberrant miRNA expression is implicated in the pathogenesis of numerous diseases including cancer, hepatitis, cardiovascular diseases and metabolic diseases. Steroid hormones regulate virtually every aspect of metabolism, and acute and chronic steroid hormone biosynthesis is primarily regulated by tissue-specific trophic hormones involving transcriptional and translational events. In addition, it is becoming increasingly clear that steroidogenic pathways are also subject to post-transcriptional and post-translational regulations including processes such as phosphorylation/dephosphorylation, protein‒protein interactions and regulation by specific miRNAs, although the latter is in its infancy state. Here, we summarize the recent advances in miRNA-mediated regulation of steroidogenesis with emphasis on adrenal and gonadal steroidogenesis.

Identification of microRNAs that Regulate the MAPK Pathway in Human Cumulus Cells from PCOS Women with Insulin Resistance

Polycystic ovary syndrome (PCOS) is one of the most common gynaecological endocrine disorders, and more than 60% of PCOS patients have varying degrees of insulin resistance (IR). The regulatory role of microRNAs (miRNAs) at post-transcriptional levels in human cumulus cells relating to IR in PCOS remains unclear. In this case-control study, 26 PCOS patients with IR (PCOS-IR) and 24 patients without IR (PCOS-control) were enrolled. We determined the differentially expressed miRNA and mRNA using next-generation sequencing technology, and these miRNAs and mRNAs were validated by quantitative real-time polymerase chain reaction (PCR). These miRNA regulating pathways (e.g., MAPK pathway) were analysed by bioinformatics analysis, and the Rap1b was demonstrated to be targeted by miR-612 based on quantitative real-time PCR, western blot and luciferase activity assay. A total of 59 known miRNAs and 617 differentially expressed genes were identified that differentially expressed between PCOS-IR and PCOS-control cumulus cells. Moreover, the potential regulating roles of miRNAs and their targeting genes in pathophysiology of IR and PCOS were analysed by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation, and several key processes were enriched, such as MAPK activity. Furthermore, Rap1b, a regulator of the MAPK pathway, was demonstrated to be suppressed directly by miR-612 in PCOS-IR cumulus cells based on negative expression correlation validation, dual luciferase activity assay and reduction of Rap1b expression after miR-612 mimics transfection. Our results suggested that miRNAs and their targeted pathways in ovarian cumulus cells may play important roles in the aetiology and pathophysiology of PCOS with IR.

The Expression of miRNAs in Human Ovaries, Oocytes, Extracellular Vesicles, and Early Embryos: A Systematic Review

The recent discovery of microRNAs (miRNAs) in human reproductive tissues and cells indicates a possible functional role in reproductive function. However, the studies published to date in female reproductive tissues/cells and embryos are inconclusive and sometimes controversial. In order to update the knowledge of this field, the present study aimed to discuss, through a systematic review, the role of miRNAs in female human reproduction and early embryogenesis. We conducted a systematic review of the published literature in MEDLINE and EMBASE databases through June 2018 (plus a complementary search until July 2019), in accordance with the PRISMA guidelines. We have included descriptive and observational studies, in which fertile/infertile women were well-defined. The primary outcome was the miRNA expression in ovaries, oocytes, extracellular vesicles, and embryos. We identified 25,204 articles, of which 28 were selected for qualitative analysis: 18 in ovaries and extracellular vesicles, three in oocytes, and seven in embryos. The present systematic review of descriptive and observational studies demonstrates that aberrant miRNA expression in female reproductive tissues/cells and embryos is related with infertility and embryogenesis errors. The expression of specific miRNAs, particularly in extracellular vesicles, may be used in the future as biomarkers of infertility and prognostic tools of embryo development.

Expression of microRNA in follicular fluid in women with and without PCOS

Several studies have shown the expression of small non-coding microRNA (miRNA) changes in PCOS and their expression in follicular fluid has been described, though the number of studies remains small. In this prospective cohort study, miRNA were measured using quantitative polymerase chain reaction (qPCR) in 29 weight and aged matched anovulatory women with PCOS and 30 women without from follicular fluid taken at the time of oocyte retrieval who were undergoing in vitro fertilization (IVF); miRNA levels were determined from a miRNA data set. 176 miRNA were detected, of which 29 differed significantly between normal women and PCOS women. Of these, the top 7 (p < 0.015) were miR-381-3p, miR-199b-5p, miR-93-3p, miR-361-3p, miR-127-3p, miR-382-5p, miR-425-3p. In PCOS, miR-382-5p correlated with age and free androgen index (FAI), miR-199b-5p correlated with anti-mullerian hormone (AMH) and miR-93-3p correlated with C-reactive protein (CRP). In normal controls, miR-127-3p, miR-382-5p and miR-425-3p correlated with the fertilisation rate; miR-127-3p correlated with insulin resistance and miR-381-3p correlated with FAI. Ingenuity pathway assessment revealed that 12 of the significantly altered miRNA related to reproductive pathways, 12 miRNA related to the inflammatory disease pathway and 6 were implicated in benign pelvic disease. MiRNAs differed in the follicular fluid between PCOS and normal control women, correlating with age, FAI, inflammation and AMH in PCOS, and with BMI, fertilization rate (3 miRNA), insulin resistance, FAI and inflammation in control women, according to Ingenuity Pathway Analysis.

High throughput circRNAs sequencing profile of follicle fluid exosomes of polycystic ovary syndrome patients

Polycystic ovary syndrome (PCOS) is one of the most prevalent reproductive disorders in women worldwide. Despite rigorous research, the exact molecular mechanism that governs PCOS pathogenesis remains unclear. To investigate the potential roles of circular RNAs (circRNAs), this study sequenced ribosomal RNA-depleted total RNA from exosomes of follicle fluids obtained from PCOS patients using non-PCOS samples as controls. Bioinformatic analysis identified 167 upregulated and 245 downregulated circRNAs from a total of 16,771 detected candidates. Functional analysis suggests that pathways related to bacterial infection, associated chronic inflammation, and oxidative stress could be targeted by the differential circRNAs in PCOS patients. The obtained sequencing results were further validated by quantitative reverse-transcription polymerase chain reaction and a circRNA-microRNA interaction network was constructed. The obtained results provide a valuable addition to the published studies on the mechanism of PCOS pathogenesis by revealing a wide variety of new circRNAs, miRNA, and gene targets that merit further investigation.

MicroRNA-200b and microRNA-200c are up-regulated in PCOS granulosa cell and inhibit KGN cell proliferation via targeting PTEN

BACKGROUND

Polycystic ovary syndrome (PCOS) is one of the most common endocrine metabolic disorders characterized by hyperandrogenism, polycystic ovaries and ovulatory dysfunction. Several studies have reported that the aberrant expression of miRNAs contributes a lot to disordered folliculogenesis in PCOS, though the role and underlying mechanism of microRNA-200b (miR-200b) and microRNA-200c (miR-200c) in the development of PCOS remain unclear.

METHODS

The expression of miR-200b in granulosa cells (GCs) derived from 90 PCOS patients and 70 controls was analyzed by using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Granulosa-like tumor cell line (KGN) was cultured for cell counting kit-8 (CCK-8) assays after over-expression of miR-200b, miR-200c or knockdown phosphatase and tensin homolog (PTEN). TargetScan was used to identify the potential targets of miR-200b and miR-200c, which was further verified by qRT-PCR, western blot and luciferase assays.

RESULTS

Significantly increased expression of miR-200b was observed in PCOS patients compared with the controls. Moreover, over-expression of miR-200b and miR-200c inhibited the proliferation of KGN cells. In addition, our results verified that miR-200b and miR-200c directly targeted PTEN, knockdown of which suppressed KGN cells proliferation.

CONCLUSION

Our findings demonstrate that miR-200b and miR-200c suppress the proliferation of KGN cells by targeting PTEN, and this might provide new evidence for abnormal proliferation of GCs in PCOS.

DNA fragmentation index, pAKT and pERK1/2 in cumulus cells are related to oocyte competence in patients undergoing in vitro fertilization programme

Activated pERK1/2 and pAKT are key players in supporting cell survival and proliferation pathways. Translocation of pERK1/2 into the nucleus, where it interacts with transcription factors and DNA itself, is instrumental in exerting an anti-apoptotic effect. In this study, pAKT levels, pERK1/2 nuclear localization and DNA fragmentation index (DFI) in cumulus cells of single cumulus-oocyte complexes of patients undergoing in vitro fertilization programmes were evaluated and correlated with the clinical outcome of the related embryos. For a positive clinical outcome of blastocyst development, pERK1/2 nuclear localization and DFI value had a significant inverse relationship, whereas the former and the intracellular accumulation of pAKT had a significant direct relationship. This relationship was not observed for the negative clinical outcome of the arrested embryos. Moreover, intracellular accumulation of pAKT and DFI value had a significant inverse relationship in all samples examined. The obtained data suggest that the intranuclear relocation of pERK1/2, along with an enhanced intracellular accumulation of pAKT, may exert a survival effect and increase cell viability, therefore providing a novel marker tool to choose the best oocyte to be fertilized and submitted to an intracytoplasmic sperm injection cycle.

Hidradenitis Suppurativa: Comprehensive Review of Predisposing Genetic Mutations and Changes

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder. A genetic component in the pathogenesis is highly likely considering that ~30% to 40% of patients with HS report a family history of the disease. The genetic mutations related to HS that have been reported to date suggest HS can be inherited as a monogenic trait because of a defect in either the Notch signaling pathway or inflammasome function, or as a polygenic disorder resulting from defects in genes regulating epidermal proliferation, ceramide production, or in immune system function. This review provides a summary of genetic mutations reported in patients diagnosed with HS and discusses the mechanisms by which these genes are involved in its pathogenesis.

Bioinformatics identification of microRNAs involved in polycystic ovary syndrome based on microarray data

Polycystic ovary syndrome (PCOS) is the most common endocrine disease in women of reproductive age. MicroRNAs (miRNAs or miRs) serve important roles in the physiological and pathological process of PCOS. To identify PCOS-associated miRNAs, the dataset GSE84376 was extracted from the Gene Expression Omnibus database. Differentially expressed miRNAs (DE-miRNAs) were obtained from Gene-Cloud Biotechnology Information and potential target genes were predicted using TargetScan, DIANA-microT-CDS, miRDB and miRTarBase tools. Gene Ontology enrichment analysis was performed using Metascape and a protein-protein interaction network was constructed using Cytoscape. Transcription factors were obtained from FunRich. DE-miRNAs were verified by reverse transcription-quantitative PCR. At the screening phase, there were seven DE-miRNAs in the PCOS group not present in the control group. In total, 935 target genes were identified, which are involved in the development and maturation of oocytes. Mitogen-activated protein kinase 1, phosphatase and tensin homolog, cAMP responsive element binding protein 1, signal transducer and activator of transcription 3, interferon γ, Fms-related tyrosine kinase 1, transcription factor p65, insulin receptor substrate 1, DnaJ homolog superfamily C member 10 and casein kinase 2 α 1 were identified as the top 10 hub genes in the protein-protein interaction network. Specificity protein 1 was the most enriched transcription factor. At the validation phase, the levels of Homo sapiens (hsa)-miR-3188 and hsa-miR-3135b were significantly higher in the PCOS group than in the control group. In addition, the expression level of hsa-miR-3135b was significantly correlated with the number of oocytes retrieved, the fertilization rate and the cleavage rate (P<0.05). The present bioinformatics study on miRNAs may offer a novel understanding of the mechanism of PCOS, and may serve to identify novel miRNA therapeutic targets.

The role of MiRNA in polycystic ovary syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder in reproductive-aged women. Clinical manifestations include hyperandrogenism, chronic anovulation, polycystic ovaries and being frequently accompanied by insulin resistance (IR) and obesity. MicroRNAs (miRNAs) are short non-coding RNAs which are involved in the regulation of gene expression at the post-transcriptional level. Altered miRNAs levels have been showed to be associated with a variety of diseases including diabetes, endometriosis and cancer. In recent years, more and more evidence suggests abnormal expression of miRNAs are detected in granulosa cells, theca cells, adipose tissue, follicular fluid, serum and peripheral blood leukocytes of women with PCOS and display vital role in the occurrence and development of PCOS. This will shed light on new strategies for the diagnosis and treatment of this syndrome. In this paper, we will review the recent research on miRNAs with respect to PCOS.

Characterization of circular RNA expression profiles in cumulus cells from patients with polycystic ovary syndrome

OBJECTIVE

To determine aberrant circular RNA (circRNA) expression profiles in cumulus cells from polycystic ovarian syndrome (PCOS) patients and identify their potential biological functions.

DESIGN

Circular RNAs microarray analysis of human tissue.

SETTING

University hospital.

PATIENT(S)

A total of 40 women, including 20 PCOS patients and 20 non-PCOS patients.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

A circRNA microarray containing probes that interrogate 21,442 human circRNAs to investigate differentially expressed circRNAs in cumulus cells, with potential target genes of significantly changed circRNAs and biological functions measured by microRNA support vector regression (mirSVR) and gene ontology (GO) analysis, with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis.

RESULT(S)

A total of 1,032 circRNAs were identified that were differentially expressed in PCOS cumulus cells, including 311 circRNAs increase and 721 circRNAs decrease (fold change ≥2). Four aberrantly expressed circRNAs reached a statistically significant result after Bonferroni correction (with Bonferroni correction, only circRNAs for which P < .05/21,442 = 2.3 × 10^-6 were considered statistically significant). Further analysis showed that aberrantly expressed circRNAs harbored microRNA binding sites, and some microRNAs were associated with PCOS. The GO and KEGG biological pathway analysis indicated that the genes with protein binding, mitotic nuclear envelope disassembly and metabolic pathways were statistically significantly enriched.

CONCLUSION(S)

Our data suggest that the aberrantly expressed circRNAs and their targeted genes might be associated with PCOS, providing new clues to find key diagnostic and therapeutic molecular biomarkers for PCOS patients.

Circular RNA expression profiling of granulosa cells in women of reproductive age with polycystic ovary syndrome

Purpose

This study aimed to explore the expression profiles of circRNA in granulosa cells of women of reproductive age with polycystic ovary syndrome (PCOS).

Methods

Total RNA was isolated from granulosa cells of 15 women with PCOS and 15 body mass index- and age-matched healthy women (control). RNA sequencing was conducted on ribosomal-depleted RNA for circRNA expression profiling. The differential expression of circRNA between women with PCOS and controls was compared and visualized using hierarchical clustering heat maps and Volcano plots. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed to determine the role of the differential expression of circRNAs. The expression rates of circRNAs were confirmed using quantitative real-time PCR (qRT-PCR) using divergent primers.

Results

A total of 4258 and 7395 candidate circRNAs were predicted in PCOS and controls, respectively, based on the RNA-sequencing data. Differences were noted in the expression patterns of circRNA between the two groups. Analysis of the expression profiles revealed that four circRNAs were upregulated, whereas 23 were downregulated in the women with PCOS. GO analysis suggested that the 27 differentially expressed circRNAs were mainly distributed in biological process pathways, particularly in pathways involving inflammation, proliferation, and the vascular endothelial growth factor-related signaling pathway. Six circRNAs were identified in PCOS-affected women using divergent primers. qRT-PCR confirmed that hsa_circ_0001577 was significantly upregulated and hsa_circ_0020093 was downregulated in the women with PCOS.

Conclusions

Several circRNAs were differentially expressed in women of reproductive age with PCOS, suggesting the involvement of these circRNAs in the development of PCOS and the potential clinical implications of their use as PCOS biomarkers.

Electronic supplementary material

The online version of this article (10.1007/s00404-019-05129-5) contains supplementary material, which is available to authorized users.

microRNA 92b-3p regulates primordial follicle assembly by targeting TSC1 in neonatal mouse ovaries

The primordial follicle pool, providing all oocytes available to a female throughout her reproductive life, is established perinatally. The formation of primordial follicle pool is regulated by precise transcriptional and post-transcriptional mechanisms. Recent studies have identified several microRNAs as post-transcriptional regulatory factors in the process of primordial follicle assembly. Here, we showed that miR-92b-3p was significantly upregulated in the stage of primordial follicle assembly in newborn mouse ovaries. Inhibiting miR-92b-3p suppressed the formation of primordial follicles, while overexpression of miR-92b-3p accelerated the processes of cyst breakdown and the following primordial follicle assembly. Accordingly, the expression of follicular development-related genes was reduced upon inhibiting of miR-92b-3p and increased under miR-92b-3p overexpression. Mechanistic studies identified TSC1 as a direct target of miR-92b-3p. miR-92b-3p could activate mTOR/Rps6 signaling through targeting and inhibiting TSC1 expression. In addition, knockdown of TSC1 showed an identical phenotype with that of miR-92b-3p overexpression in accelerating processes of cyst breakdown and primordial follicle formation. Thus, our work demonstrates that miR-92b-3p is a novel regulator of primordial follicle assembly by negatively regulating TSC1 in mTOR/Rps6 signaling.

Higher chromosomal aberration rate in miscarried conceptus from polycystic ovary syndrome women undergoing assisted reproductive treatment

OBJECTIVE

To assess the potential association between polycystic ovary syndrome (PCOS) and chromosomally aberrant miscarriage during treatment with assisted reproductive technology (ART).

DESIGN

A retrospective, single-center study.

SETTING

University-affiliated reproductive center.

PATIENT(S)

A total of 328 patients sent their first trimester miscarried chorionic villus for genetic examination after ART in our center from January 2013 to September 2016, of which 119 cases were women with PCOS and 209 were non-PCOS controls. No known definite miscarriage-related concomitants existed in any study subject.

INTERVENTION(S)

Single nucleotide polymorphism array analysis was performed on all collected samples.

MAIN OUTCOME MEASURE(S)

Frequency of aberrant karyotype of miscarried conceptus and the correlation between PCOS and chromosomally aberrant miscarriage.

RESULT(S)

A total of 173 (52.7% of 328) conceptuses were identified as chromosomally aberrant by single nucleotide polymorphism array. Chromosomal aberrations were more frequent in conceptuses from PCOS patients compared with controls (61.3% vs. 47.8%). Furthermore, both univariate and multivariable analysis identified PCOS as a risk factor for an embryo/fetus to be chromosomally abnormal, with odds ratios of 1.957 (95% confidence interval, 1.067-3.590) and 2.008 (95% confidence interval, 1.038-3.883), respectively.

CONCLUSION(S)

Women with PCOS were at an increased risk of miscarrying a chromosomally aberrant embryo/fetus compared with non-PCOS controls during ART. Mechanisms require further investigation. Preimplantation genetic screening might be an effective approach to decrease the risk of spontaneous miscarriage for women with PCOS.

MiR-222 promotes the progression of polycystic ovary syndrome by targeting p27 Kip1

Polycystic ovary syndrome (PCOS) is one of the most complex and common reproductive and endocrinologic disorders in the child-bearing age of women. Recently, miR-222 were reported to be associated with the etiology of PCOS. However, the function of miR-222 during the pathogenesis of PCOS remains unclear. In the present study, we aimed to investigate the role of miR-222 in PCOS. Firstly, miR-222 expression was examined by quantitative real-time PCR (qRT-PCR) in PCOS. The effects of miR-222 on proliferation, apoptosis and cell cycle in KGN cells were analyzed by CCK-8 assay and flow cytometry analysis, respectively. In addition, bioinformatics analysis was used to predict the target genes of miR-222, and dual-luciferase reporter assay was applied to verified the interaction between miR-222 and p27 Kip1 in KGN cells. Moreover, the expressions of p27 Kip1 in KGN cells treated with miR-222 mimics or miR-222 inhibitor were evaluated by qRT-PCR and western blot assays. The results showed that the expression of miR-222 was remarkably upregulated in PCOS tissues compared with corresponding normal tissues. In the gain-of-function and loss-of-function assays, we revealed that miR-222 mimics significantly promoted cell proliferation, while miR-222 inhibitor induced cell apoptosis and cell cycle arrested. Furthermore, p27 Kip1 was identified as a target gene of miR-222, and could be negatively regulated by miR-222 mimics in KGN cells. In conclusion, our findings suggested that miR-222 may promote the progression of PCOS by targeting p27 Kip1.

MicroRNAs in ovarian follicular atresia and granulosa cell apoptosis

MicroRNAs (miRNAs) are short, noncoding RNAs that posttranscriptionally regulate gene expression. In the past decade, studies on miRNAs in ovaries have revealed the key roles of miRNAs in ovarian development and function. In this review, we first introduce the development of follicular atresia research and then summarize genome-wide studies on the ovarian miRNA profiles of different mammalian species. Differentially expressed miRNA profiles during atresia and other biological processes are herein compared. In addition, current knowledge on confirmed functional miRNAs during the follicular atresia process, which is mostly indicated by granulosa cell (GC) apoptosis, is presented. The main miRNA families and clusters, including the let-7 family, miR-23-27-24 cluster, miR-183-96-182 cluster and miR-17-92 cluster, and related pathways that are involved in follicular atresia are thoroughly summarized. A deep understanding of the roles of miRNA networks will not only help elucidate the mechanisms of GC apoptosis, follicular development, atresia and their disorders but also offer new diagnostic and treatment strategies for infertility and other ovarian dysfunctions.

Characterization of the miRNA regulators of the human ovulatory cascade

Ovarian follicular development and ovulation are complex and tightly regulated processes that involve regulation by microRNAs (miRNAs). We previously identified differentially expressed mRNAs between human cumulus granulosa cells (CGCs) from immature early antral follicles (germinal vesicle - GV) and mature preovulatory follicles (metaphase II - M2). In this study, we performed an integrated analysis of the transcriptome and miRNome in CGCs obtained from the GV cumulus-oocyte complex (COC) obtained from IVM and M2 COC obtained from IVF. A total of 43 differentially expressed miRNAs were identified. Using Ingenuity IPA analysis, we identified 7288 potential miRNA-regulated target genes. Two hundred thirty-four of these target genes were also found in our previously generated ovulatory gene library while exhibiting anti-correlated expression to the identified miRNAs. IPA pathway analysis suggested that miR-21 and FOXM1 cooperatively inhibit CDC25A, TOP2A and PRC1. We identified a mechanism for the temporary inhibition of VEGF during ovulation by TGFB1, miR-16-5p and miR-34a-5p. The linkage bioinformatics analysis between the libraries of the coding genes from our preliminary study with the newly generated library of regulatory miRNAs provides us a comprehensive, integrated overview of the miRNA-mRNA co-regulatory networks that may play a key role in controlling post-transcriptomic regulation of the ovulatory process.

Construction and analysis of a lncRNA (PWRN2)-mediated ceRNA network reveal its potential roles in oocyte nuclear maturation of patients with PCOS

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in women. An lncRNA, namely, Prader-Willi region nonprotein coding RNA 2 (PWRN2), was up-regulated in the cumulus cells of patients with PCOS. However, the molecular mechanism of PWRN2 in PCOS remains largely unknown.

METHODS

In this study, the expression levels of PWRN2 were tested in cumulus cells through qRT-PCR analysis to confirm its potential roles in oocyte nuclear maturation of PCOS. A PWRN2-mediated ceRNA network was constructed based on three microarray datasets to investigate the molecular mechanism of PWRN2 in oocyte development of patients with PCOS. The direct interactions of the candidate genes of the ceRNA network were also demonstrated by dual-luciferase reporter assay.

RESULTS

PWRN2 was found to be associated with oocyte nuclear maturation in patients with PCOS in contrast to that in normal patients. Based on the microarray data, 176 lncRNAs (118 up-regulated and 58 down-regulated) and 131 mRNAs (84 up-regulated and 47 down-regulated) were identified to be regulated by PWRN2. A PWRN2-miR-92b-3p-TMEM120B ceRNA network was constructed based on results of analysis of the combined three microarray datasets (lncRNA+mRNA microarray in KGN/shPWRN2 in this study, miRNAs microarray and lncRNA+mRNA microarray in PCOS cumulus cells reported in previous studies). The coexpression characteristics of the genes (PWRN2, miR-92b-3p and TMEM120B) were detected in the cumulus cells of cumulus-oocyte complexes at different nuclear maturity stages in PCOS. These results are in accordance with the ceRNA hypothesis. Moreover, luciferase activity assay revealed that miR-92b-3p directly binds to PWRN2 and targets TMEM120B.

CONCLUSIONS

PWNR2 plays important roles in oocyte nuclear maturation in PCOS by functioning as a ceRNA to reduce the availability of miR-92b-3p for TMEM120B target binding during oocyte maturation in PCOS. Our findings would provide new information and clarify abnormal oocyte development in PCOS.

Genome-wide screening differential long non-coding RNAs expression profiles discloses its roles involved in OHSS development

OBJECTIVE

To screen differentially expressed lncRNAs involved in OHSS. OHSS is defined as ovarian hyperstimulation syndrome. It is characterized as enlarged ovary and increased vascular permeability.

DESIGN

Case-control study.

SETTING

University-affiliated hospital.

PATIENT(S)

Patients with OHSS high risk (n = 30) and low risk (n = 30) were included in this study.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

LncRNAs from women with OHSS high risk and low risk were used for high-throughput sequencing profiling. The eight most differentially expressed lncRNAs in granulosa cells were validated by semi-quantitative reverse transcription-polymerase chain reaction analysis.

RESULT(S)

A total of 23,815 lncRNAs were detected and 482 were differentially expressed (fold-change ≥2; p < 0.05, FDR value < 0.001), of which 205 were upregulated and 277 were downregulated. Lnc-SEC16B.1-6, lnc-SNURF-13, lnc-LGR6-6, and lnc-H2AFY2-2 were up-regulated, while lnc-BRD2-2, lnc-HSPA6-2, and lnc-CLIC6-5 were downregulated significantly in granulosa cells. These results were confirmed by qRT-PCR. KEGG pathways and Gene Ontology enrichment analysis revealed that several biological processes were significantly associated. Meanwhile, the lncRNA/miRNA interaction network was established according to ceRNA network model.

CONCLUSION(S)

Comprehensive expression screening identified eight novel lncRNAs associated with risk factors of OHSS process. Although it is unclear how these altered lncRNAs regulate the process of OHSS, our findings suggest these lncRNAs may be novel players in OHSS development.

hsa-miRNA-154-5p expression in plasma of endometriosis patients is a potential diagnostic marker for the disease

RESEARCH QUESTION

As microRNA (miRNA) are stable in circulation, this study tested whether they could serve as putative non-invasive biomarkers for endometriosis, and their expression differences between endometriosis patients and controls. It also addressed whether the combination of differently expressed miRNA together with clinical parameters in a statistical model could distinguish between endometriosis patients and controls.

DESIGN

This prospective cohort study explored the possibility of using changes in extracellular miRNA spectra in plasma of 51 patients with endometriosis compared with 41 controls combined with clinical data as non-invasive biomarkers for the disease. The project was divided into three different phases for biomarker screening, discovery and validation. The differences in expression levels of plasma miRNA obtained from women with and without endometriosis were analysed with quantitative PCR-based microarrays. The diagnostic performance of the selected individual and/or combined differentially expressed miRNA candidates and clinical parameters was assessed using in silico bioinformatics modelling and receiver operating characteristic curve analysis.

RESULTS

Data showed that a specific plasma miRNA signature is associated with endometriosis and that hsa-miR-154-5p, which alone or in combination with hsa-miR-196b-5p, hsa-miR-378a-3p, and hsa-miR-33a-5p and the clinical parameters of body mass index and age, are potentially applicable for non-invasive diagnosis of the disease. Changes in the levels of expression of certain circulating plasma miRNA also occurred within the phases of the menstrual cycle.

CONCLUSIONS

miRNA seem to be promising candidates for the non-invasive diagnosis of endometriosis. Further, other clinical parameters may help in distinguishing women suffering from endometriosis from healthy individuals.

Exosomal MicroRNAs in Milk from Mothers Delivering Preterm Infants Survive in Vitro Digestion and Are Taken Up by Human Intestinal Cells

SCOPE

This study investigates the ability of preterm milk exosomes to survive gastric/pancreatic digestion, internalization by intestinal epithelia, and the microRNAs (miRNAs) contents.

METHODS AND RESULTS

At average infant age 1 week and 6 days, milk is collected from mothers who delivered preterm and term infants (n = 10). Milk is exposed to conditions simulating infant gut digestion. Exosomes are isolated and lysed, and the exposed miRNAs are sequenced. Preterm milk exosomes survive in vitro digestion, and can be taken up by intestinal epithelia. Three hundred and thirty miRNAs are identified as preterm milk exosome miRNAs, and in vitro digestion does not have a pronounced effect on their expression. The abundant miRNAs in preterm milk exosomes are similar to those from term milk. Twenty-one low abundance miRNAs are specifically expressed in preterm milk exosomes compared to early term milk in the current study and what previously is found in mature term milk.

CONCLUSION

These results for the first time reveal the survivability of preterm milk exosomes following simulated gastric/pancreatic digestion. The authors demonstrate the richness of the miRNAs content in these exosomes. The results improve the knowledge of preterm milk biology and the molecular basis by which exosome miRNAs may uniquely affect preterm infants during early development.

Altered microRNA and Piwi-interacting RNA profiles in cumulus cells from patients with diminished ovarian reserve

Diminished ovarian reserve (DOR) is defined as decreased number or quality of follicles and oocytes in a woman at childbearing age. It is estimated that up to 10% of women in the general population may suffer from DOR. This study aims to comprehensively characterize microRNA (miRNA) and Piwi-interacting RNA (piRNA) expression profiles in cumulus cells of DOR patients. Cumulus cells were collected from 20 women of similar chronological age who received assisted reproductive technology treatment: 10 with DOR and 10 with normal ovarian reserve (NOR). The small RNAs were extracted from each sample and reverse transcribed. Deep sequencing and bioinformatic analysis were performed to identify the small noncoding RNA profiles. The rRNAs were the most abundant small RNA class in cumulus cells derived from human MII oocytes, following were miRNAs and tRNAs. Twenty-six piRNAs, 79 annotated miRNAs, and 5 novel miRNAs were identified differentially expressed. In DOR group, the chromosomal strand bias patterns of piRNAs on chromosome 1, 3, 5, and X were distinct from its counterpart in NOR group. The involved biological pathways from the putative target genes of differentially expressed miRNAs were enriched by using GO analysis and KEGG pathway annotations, and mTOR pathway and meiosis-associated biological processes were enriched. This study provided additional information on the dysfunctions of cumulus cells in patients with diminished ovarian reserve. Future investigations will involve the characterization of specific functional roles of noncoding small RNA in ovarian reserve regulation.

Cross-regulation between Notch signaling pathway and miRNA machinery in cancer

Despite their simple structure, the Notch family of receptors regulates a wide-spectrum of key cellular processes including development, tissue patterning, cell-fate determination, proliferation, differentiation and, cell death. On the other hand, accumulating date pinpointed the role of non-coding microRNAs, namely miRNAs in cancer initiation/progression via regulating the expression of multiple oncogenes and tumor suppressor genes, as such the Notch signaling. It is now documented that these two partners are in one or in the opposite directions and rule together the cancer fate. Here, we review the current knowledge relevant to this tricky interplay between different miRNAs and components of Notch signaling pathway. Further, we discuss the implication of this crosstalk in cancer progression/regression in the context of cancer stem cells, tumor angiogenesis, metastasis and emergence of multi-drug resistance. Understanding the molecular cues and mechanisms that occur at the interface of miRNA and Notch signaling would open new avenues for development of novel and effective strategies for cancer therapy.

Identification of microRNAs and genes associated with hyperandrogenism in the follicular fluid of women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disease, which is characterized by hyperandrogenism (HA), chronic anovulation, polycystic ovaries, insulin resistance, and obesity. At present, the mechanism by which PCOS/HA occurs has not been fully elucidated, thus, the mechanisms behind and interventions for HA in PCOS are current hot topics in research. MiRNAs have recently been shown to serve as diagnostic or prognostic biomarkers in patients with cancer. Thus, we are currently focused on studying the altered expression of miRNAs in follicular fluid and their correlation with HA in PCOS. Illumina deep sequencing technology was used to explore different miRNAs in the follicular fluid of women with PCOS/HA and in the follicular fluid of women in a control group. Target prediction databases were then used to analyse the target genes of different expressed miRNAs, and GO analysis and the KEGG pathway database were used to identify the functions and the main biochemical and signalling pathways of differentially expressed target genes. The expression levels of 263 miRNAs were significantly different (>2-fold up-regulated or <0.5-fold down-regulated, P < 0.05) between the two groups of women. For example, the expression levels of miRNA (200a-3p, 10b-3p, 200b-3p, 29c-3p, 99a-3p, and 125a-5p) were significantly increased, while there was a decreased expression of miR-105-3p in PCOS patients with respect to the control. Literature has shown that the above seven miRNAs were associated with HA in PCOS. Furthermore, 31 770 genes were predicted to be targets of the 263 differentially expressed microRNAs. GO analysis and the KEGG pathway database showed involvement of these target genes in HA in PCOS. These results suggest the presence of differentially expressed miRNAs in the follicular fluid of women with PCOS/HA versus women in the control group. The potential role of these microRNAs was elucidated using bioinformatics tools and was found to be involved in the regulation of different pathways, biological functions, and cellular components underlying PCOS. The results of this research may reveal new mechanisms of PCOS/HA and suggest potential treatment targets.

Inhibition of miR-361-5p suppressed pulmonary artery smooth muscle cell survival and migration by targeting ABCA1 and inhibiting the JAK2/STAT3 pathway

MicroRNAs play a crucial role in the progression of pulmonary arterial hypertension (PAH). The aim of this study was to investigate the effect of miR-361-5p on the proliferation, migration and apoptosis of pulmonary artery smooth muscle cells (PASMCs) that under the treatment of hypoxia and explore the underlying mechanisms. The results proved that hypoxia noticeably up-regulated the expression of miR-361-5p in PASMCs in comparison to the normoxia-treated cells, while TNF-α and IL-6 stimulation had no obvious effects on miR-361-5p level. Hypoxia induced miR-361-5p elevation in a HIF-1α-dependent manner. Inhibition of miR-361-5p dramatically inhibited hypoxia-induced cell proliferation and migration. miR-361-5p inhibition also rescued hypoxia exposure caused suppression of PASMCs apoptosis. In addition, the results showed that ABCA1 was a direct target of miR-361-5p and was down-regulated in hypoxia-induced PASMCs. Hypoxia and TNF-α or IL-6 stimulation significantly inhibited ABCA1 expression. In addition, overexpression of ABCA1 enhanced the effect of miR-361-5p on hPASMCs. Furthermore, the inhibition of miR-361-5p significantly down-regulated the expression level of p-JAK2 and p-STAT3. In conclusion, it may suggest that the suppression of miR-361-5p suppressed PASMC survival and migration by targeting ABCA1 and inhibiting the JAK2/STAT3 pathway.

Functional Characterization of MicroRNA-27a-3p Expression in Human Polycystic Ovary Syndrome

The goal of this study was to characterize the function of microRNA-27a-3p (miR-27a-3p) in polycystic ovary syndrome (PCOS). miR-27a-3p expression was analyzed in excised granulosa cells (GCs) from 21 patients with PCOS and 12 normal patients undergoing in vitro fertilization cycle treatments and in 17 nontreated cuneiform ovarian resection PCOS samples and 13 control ovarian samples from patients without PCOS. We found that the expression of miR-27a-3p was significantly increased in both excised GCs and the ovaries of patients with PCOS compared with the controls. Insulin treatment of the human granulosa-like tumor cell line (KGN) resulted in decreased downregulated expression of miR-27a-3p, and this effect appeared to be mediated by signal transducer and activator of transcription STAT1 and STAT3. The overexpression of miR-27a-3p in KGN cells inhibited SMAD5, which in turn decreased cell proliferation and promoted cell apoptosis. After KGN cells were stimulated with insulin for 48 hours, there was increased expression of SMAD5 protein and decreased apoptosis. Additionally, knockdown/overexpression of SMAD5 in KGN cells reduced/increased cell number and promoted/inhibited cell apoptosis. Insulin-stimulated primary GCs isolated from patients with PCOS, in contrast to normal GCs or KGN cells, did not exhibit decreased miR-27a-3p expression. The differences in the expression levels in KGN cells and human PCOS GCs are likely explained by increased miR-27a-3p expression in the GCs caused by insulin resistance in PCOS. Taken together, our data provided evidence for a functional role of miR-27a-3p in the GCs' dysfunction that occurs in patients with PCOS.

MicroRNA-27a-3p affects estradiol and androgen imbalance by targeting Creb1 in the granulosa cells in mouse polycytic ovary syndrome model

Polycystic ovary syndrome (PCOS) is a common endocrine abnormality in women characterized by a menstrual disturbance with chronic anovulation and hyperandrogenism, polycystic ovaries, and insulin resistance. MicroRNAs (miRNAs) are important fine-tune regulators involved in various physiological and pathological processes, but their actions are not fully understood. In this study, we observed the increased expression of miR-27a-3p in the ovaries of mice with PCOS and explored its functions in primary mouse granulosa cells (mGCs) and the mouse granulosa-like tumor cell line, KK-1, using several approaches. QPCR results showed that miR-27a-3p expression was significantly higher in mGCs at the preantral follicle (PrF) stage. Using flow cytometry and hormone analysis, we found that overexpression of miR-27a-3p promoted apoptosis and inhibited estradiol (E₂) production in KK-1 cells. Moreover using a luciferase assay and Western blotting analysis, we verified that the gene of cyclic AMP response element (CRE)-binding protein 1 (Creb1) was a potential target of miR-27a-3p, which in effect hindered the expression of its downstream factor cytochrome P450 family 19 subfamily A polypeptide 1 (Cyp19a1). With the decrease of aromatase activity, testosterone (T) is reduced to dihydrotestosterone (DHT) and this exerts its effect of upregulation of the miR-27a-3p expression. The imbalance of androgen and E₂ levels affected by miR-27a-3p and its function of promoting GC apoptosis could be involved in the pathophysiology of PCOS. Our results indicate that miR-27a-3p in PCOS GCs may play an important role in ovarian follicular development and provide new insights into GC dysfunction in PCOS.

Pathway and network-based analysis of genome-wide association studies and RT-PCR validation in polycystic ovary syndrome

The purpose of this study was to identify promising candidate genes and pathways in polycystic ovary syndrome (PCOS). Microarray dataset GSE345269 obtained from the Gene Expression Omnibus database includes 7 granulosa cell samples from PCOS patients, and 3 normal granulosa cell samples. Differentially expressed genes (DEGs) were screened between PCOS and normal samples. Pathway enrichment analysis was conducted for DEGs using ClueGO and CluePedia plugin of Cytoscape. A Reactome functional interaction (FI) network of the DEGs was built using ReactomeFIViz, and then network modules were extracted, followed by pathway enrichment analysis for the modules. Expression of DEGs in granulosa cell samples was measured using quantitative RT-PCR. A total of 674 DEGs were retained, which were significantly enriched with inflammation and immune-related pathways. Eight modules were extracted from the Reactome FI network. Pathway enrichment analysis revealed significant pathways of each module: module 0, Regulation of RhoA activity and Signaling by Rho GTPases pathways shared ARHGAP4 and ARHGAP9; module 2, GlycoProtein VI-mediated activation cascade pathway was enriched with RHOG; module 3, Thromboxane A2 receptor signaling, Chemokine signaling pathway, CXCR4-mediated signaling events pathways were enriched with LYN, the hub gene of module 3. Results of RT-PCR confirmed the finding of the bioinformatic analysis that ARHGAP4, ARHGAP9, RHOG and LYN were significantly upregulated in PCOS. RhoA-related pathways, GlycoProtein VI-mediated activation cascade pathway, ARHGAP4, ARHGAP9, RHOG and LYN may be involved in the pathogenesis of PCOS.

MicroRNA-141-3p targets DAPK1 and inhibits apoptosis in rat ovarian granulosa cells

The polycystic ovary syndrome (PCOS) is a complex and heterogeneous endocrine disorder. MicroRNAs negatively regulate the expression of target genes at posttranscriptional level by binding to the 3' untranslated region of target genes. Our previous study showed that miR-141-3p was dramatically decreased in the ovaries of rat PCOS models. In this study, we aimed to characterize the target of miR-141-3p in rat ovarian granulosa cells. 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay showed that cell viability was dramatically increased when miR-141-3p was overexpressed but was decreased when miR-141-3p was interfered. Flow cytometry showed that cell apoptotic rate was dramatically decreased when miR-141-3p was overexpressed but was increased when miR-141-3p was interfered. Bioinformatics analysis predicted that death-associated protein kinase 1 (DAPK1) might be the target gene of miR-141-3p because the 3' untranslated region of DAPK1 contains sequences complementary to microRNA-141-3p. Transfection with miR-141-3p mimics and inhibitor into granulosa cells showed that both DAPK1 mRNA and protein levels were negatively correlated with miR-141-3p level. Dual-luciferase reporter assay established that DAPK1 was the target of miR-141-3p. Taken together, our data indicate that miR-141-3p may inhibit ovarian granulosa cell apoptosis via targeting DAPK1 and is involved in the etiology of PCOS.

The role of Notch signalling in ovarian angiogenesis

In adults, the ovary is characterized with extensive angiogenesis and regular intervals of rapid growth. Ovarian function is dependent on the network of angiogenic vessels which enable the follicle and/or corpus luteum to receive oxygen, nutrients and hormonal support. Abnormal angiogenesis is involved in the induction and development of pathological ovary, such as polycystic ovary syndrome and ovarian cancer. Notch signalling pathway is one of the primary regulators of angiogenesis and a therapeutic target for ovarian diseases. Here, we will review literatures on the expression pattern of Notch pathway components in the ovary and on the role of Notch signalling pathway on ovarian angiogenesis.

The role of Notch signaling in the mammalian ovary

The Notch pathway is a contact-dependent, or juxtacrine, signaling system that is conserved in metazoan organisms and is important in many developmental processes. Recent investigations have demonstrated that the Notch pathway is active in both the embryonic and postnatal ovary and plays important roles in events including follicle assembly and growth, meiotic maturation, ovarian vasculogenesis and steroid hormone production. In mice, disruption of the Notch pathway results in ovarian pathologies affecting meiotic spindle assembly, follicle histogenesis, granulosa cell proliferation and survival, corpora luteal function and ovarian neovascularization. These aberrations result in abnormal folliculogenesis and reduced fertility. The knowledge of the cellular interactions facilitated by the Notch pathway is an important area for continuing research, and future studies are expected to enhance our understanding of ovarian function and provide critical insights for improving reproductive health. This review focuses on the expression of Notch pathway components in the ovary, and on the multiple functions of Notch signaling in follicle assembly, maturation and development. We focus on the mouse, where genetic investigations are possible, and relate this information to the human ovary.

Oocyte Competence in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and affects fertility and pregnancy in cases of oligoanovulation. Ovulation induction is often used to treat anovulatory patients with PCOS, but many of these women fail to conceive and resort to assisted reproductive technologies. Alterations in oocyte competence (OC) are considered potential causative factors for subfertility in women with PCOS. In this review we present and critically assess all recent clinical and experimental data regarding OC in women with PCOS. Our analysis demonstrates that the contribution of OC to reproductive potential in women with PCOS varies and largely depends on the PCOS phenotype and comorbidities associated with PCOS.

Deregulation of RUNX2 by miR-320a deficiency impairs steroidogenesis in cumulus granulosa cells from polycystic ovary syndrome (PCOS) patients

Deregulation of epigenetic modification by microRNAs (miRNAs) contributes to the development of estrogen deficiency, a hallmark of the multigenic endocrine disorder polycystic ovary syndrome (PCOS), but its etiology remains unclear. Previous study has pointed to a tight association between miR-320a expression and oocyte development in human follicular fluid. Given that the bi-directional communication existing between cumulus cells (CCs) and follicular fluid is essential for ovarian steroidogenesis and CCs are the main site where estrogen is finally synthesized, it is intriguing to know whether miR-320a have any regulatory roles in this unique cell. Here we report that miR-320a expression is significantly down-regulated in primary CCs from PCOS patients and this down-regulation promotes estrogen deficiency in CCs. From a mechanistic standpoint, IGF1 regulates miR-320a expression in CCs, and miR-320a could potentiate the steroidogenesis in CCs through modulation of CYP11A1 and CYP19A1 expression, by directly targeting 3'untranslated region (3'UTR) of the osteogenic transcription factor RUNX2. Overall, our results strongly suggest that deregulation of miR-320a/RUNX2/CYP11A1 (CYP19A1) cascade plays an important role in the development of estrogen deficiency in human CCs. Testing patients for miR-320a/RUNX2 expression ratios may provide more accurate diagnostic information and could influence the recommended course of treatment for PCOS.

Inside the granulosa transcriptome

The somatic component of follicular structure is a mixture of different cell types, represented by Granulosa cells (GCs) that are the paracrine regulators of the oocyte growth. GCs finely support this process by a continuous bidirectional talk with oocyte, which ensure oocyte quality and competence. Specific pathways are involved in the cross-talk and in both GCs and oocyte development. This review summarizes data from GCs gene expression analysis concerning both their physiological role and their interaction with oocyte. We also explore the CGs transcriptome modifications induced by controlled ovarian stimulation (COS) or pathological conditions and their impact in reproduction. The transcriptome analysis of GCs could be a powerful tool to improve our knowledge about the pathways involved in oocyte development. This approach, associated with new technologies as RNA-seq could allow the identifications of new noninvasive biological markers of oocyte quality to increase the efficiency of clinical IVF. Moreover, GCs expression analysis could be useful to shed light on new therapeutic targets by providing new options for the treatment of infertility.

MicroRNA-145 Negatively Regulates Cell Proliferation Through Targeting IRS1 in Isolated Ovarian Granulosa Cells From Patients With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a complex, heterogeneous endocrine and metabolic disorder affecting 5% to 10% of reproductive-age women. A high rate of granulosa cell (GC) proliferation contributes to the abnormal folliculogenesis in patients with PCOS. Evidence has proved that dysregulation of microRNAs is involved in the pathogenesis of PCOS. In this study, we investigated the effect of miR-145 on cell proliferation and the underlying mechanism of miR-145 in isolated human GCs from the aspirated follicular fluid in women with PCOS. Our findings showed that miR-145 is downregulated in human GCs from PCOS. The miR-145 mimics suppress cell proliferation and promoted cell apoptosis in human GCs from PCOS. However, miR-145 inhibitor promotes cell proliferation and inhibited cell apoptosis. Moreover, using a dual-luciferase reporter assay, we confirmed that the insulin receptor substrate 1 (IRS1) gene is a direct target of miR-145. The miR-145 mimics inhibited messenger RNA and protein IRS1 expression levels, and silencing of IRS1 by small interfering RNA inhibits human GC proliferation, but IRS1 overexpression abrogates the suppressive effect of miR-145 mimics. Furthermore, miR-145 mimics can inhibit the activation of p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-regulated kinase (ERK). The IRS1 overexpression abrogates the suppressive effect of miR-145 mimics on MAPK/ERK signaling pathways. Together, miR-145 mimics suppress cell proliferation by targeting and inhibiting IRS1 expression to inhibit MAPK/ERK signaling pathways. Our study further found that high concentrations of insulin decreases the miR-145 expression, upregulates IRS1, and promotes cell proliferation. These observations showed that miR-145 is a novel and promising molecular target for improving the dysfunction of GCs in PCOS.

Cellular and viral microRNAs in sepsis: mechanisms of action and clinical applications

Regardless of its etiology, once septic shock is established, survival rates drop by 7.6% for every hour antibiotic therapy is delayed. The early identification of the cause of infection and prognostic stratification of patients with sepsis are therefore important clinical priorities. Biomarkers are potentially valuable clinical tools in this context, but to date, no single biomarker has been shown to perform adequately. Hence, in an effort to discover novel diagnostic and prognostic markers in sepsis, new genomic approaches have been employed. As a result, a number of small regulatory molecules called microRNAs (miRNAs) have been identified as key regulators of the inflammatory response. Although deregulated miRNA expression is increasingly well described, the pathophysiological roles of these molecules in sepsis have yet to be fully defined. Moreover, non-human miRNAs, including two Kaposi Sarcoma herpesvirus-encoded miRNAs, are implicated in sepsis and may drive enhanced secretion of pro-inflammatory and anti-inflammatory cytokines exacerbating sepsis. A better understanding of the mechanism of action of both cellular and viral miRNAs, and their interactions with immune and inflammatory cascades, may therefore identify novel therapeutic targets in sepsis and make biomarker-guided therapy a realistic prospect.

The Role of Serum MicroRNA-6767-5p as a Biomarker for the Diagnosis of Polycystic Ovary Syndrome

Background

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder, and the underlying molecular mechanisms are not clear. To date, few studies have been conducted on the altered expression of serum microRNAs (miRNAs) in women with PCOS. The present study was performed to examine the role of the serum miRNA as a biomarker for the diagnosis of PCOS and its relationship with metabolic and reproductive traits.

Methods

A cross-sectional comparison was made in 21 women with PCOS and age- and body mass index (BMI)- matched 21 healthy women in an academic center laboratory between December 2008 and October 2010. We selected miRNAs that were more than 1.5-fold up-regulated or less than 0.67-fold down-regulated in women with PCOS compared with controls using the SurePrint G3 Human miRNA Microarray. Subsequently, we validated the relative expression of the miRNAs using TaqMan quantitative real-time polymerase chain reaction (RT-qPCR) assays.

Results

Serum miRNA-4522, miRNA-324-3p, and miRNA-6767-5p were down-regulated in women with PCOS compared with controls in the microarray analysis. Among these miRNAs, serum miRNA-6767-5p was validated (fold change in women with PCOS/controls = 0.39, P-value<0.05) by RT-qPCR. The miRNA-6767-5p was negatively associated with fasting glucose (β = -0.370) and positively associated with the number of menses per year (β = 0.383) after adjustment for age and BMI (Ps<0.05). Genes targeted by miRNA-6767-5p were involved in the cell cycle and the immune system.

Conclusions

Serum miRNA-6767-5p may be a novel candidate as a molecular biomarker in the diagnosis of PCOS and may participate in the development of the metabolic and reproductive traits of PCOS.

Identification of altered microRNAs and mRNAs in the cumulus cells of PCOS patients: miRNA-509-3p promotes oestradiol secretion by targeting MAP3K8

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in women and is characterised by polycystic ovaries, hyperandrogenism and chronic anovulation. Although the clinical and biochemical signs of PCOS are typically heterogeneous, abnormal folliculogenesis is considered a common characteristic of PCOS. Our aim is to identify the altered miRNA and mRNA expression profiles in the cumulus cells of PCOS patients to investigate their molecular function in the aetiology and pathophysiology of PCOS. In this study, the miRNA expression profiles of the cumulus cell samples isolated from five PCOS and five control patients were determined by an miRNA microarray. At the same time, the altered mRNA profiles of the same cumulus cell samples were also identified by a cDNA microarray. From the microarray data, 17 miRNAs and 1263 mRNAs showed significantly different expression in the PCOS cumulus cells. The differentially expressed miRNA-509-3p and its potential target gene (MAP3K8) were identified from the miRNA and mRNA microarrays respectively. The expression of miRNA-509-3p was up-regulated and MAP3K8 was down-regulated in the PCOS cumulus cells. The direct interaction between miRNA-509-3p and MAP3K8 was confirmed by a luciferase activity assay in KGN cells. In addition, miRNA-509-3p mimics or inhibitor transfection tests in KGN cells further confirmed that miRNA-509-3p improved oestradiol (E2) secretion by inhibiting the expression of MAP3K8 These results help to characterise the pathogenesis of anovulation in PCOS, especially the regulation of E2 production.

High-throughput sequencing reveals differential expression of miRNAs in prehierarchal follicles of laying and brooding geese

Broodiness is the primary factor influencing egg production in geese, in which several genes and miRNAs participate. Detailed spatiotemporal profiles of miRNAs encompassing follicle development levels, however, are lacking. In this study, we collected preovulatory follicles (classified as small white follicles, large white follicles, and small yellow follicles) from brooding and laying geese and aimed to analyze microRNA (miRNA or miR) during folliculogenesis. High-throughput sequencing and bioinformatics analysis were used to identify the miRNAs involved in follicle development. The let7 family, miR-10 family, and miR-143 family were abundant in these libraries, and they have been suggested to play a housekeeping role during folliculogenesis. Joint comparisons revealed 23 upregulated and 21 downregulated miRNAs (in at least two comparisons of follicles during brooding and laying, P < 0.1) in the laying stage. Unlike reproduction pathways reported for ovaries, GO and KEGG analysis suggested pathways for cell apoptosis and proliferation, such as the regulation of actin cytoskeleton, endocytosis, axon guidance, pathways in cancer, tight junctions, focal adhesion, the MAPK signaling pathway, cytokine-cytokine receptor interactions, and the Wnt signaling pathway in folliculogenesis. This study revealed the miRNAs that were directly involved in follicular atresia, and our results added to the understanding of the functional involvement of miRNAs during specific stages of follicle development.

MicroRNA Expression is Altered in Granulosa Cells of Ovarian Hyperresponders

Controlled ovarian stimulation plays an integral role in assisted reproduction technology, but individual patients have different responses to exogenous gonadotropins. In order to determine whether microRNAs (miRNAs) have a regulatory role in ovarian response, we profiled the expression of microRNAs in isolated ovarian granulosa cells collected from ovarian hyperresponders and normal responders using microarrays and validated the expression of selected miRNAs using quantitative polymerase chain reaction (PCR). There were 81 miRNAs differentially expressed between the 2 groups, with 45 increased and 36 decreased in the high response group. Bioinformatics analysis of these altered miRNAs and their target genes revealed some significantly enriched pathways, including regulation of the cell cycle, transcription, cell proliferation, and gonadotrophin releasing hormone signaling pathway. The expression of hsa-miR-513a-5p, hsa-miR-27b-3p, hsa-miR-19b-3p, hsa-miR-3201, hsa-miR-423-5p, hsa-miR-193b-5p, and hsa-miR-202-3p was validated by real-time PCR. Hsa-miR-423-5p, predicted to target anti-Mullerian hormone, cytochrome P450, family 19, subfamily A, polypeptide 1, methylenetetrahydrofolate reductase, progesterone receptor, and follicle stimulating hormone, β-polypeptide was found to have significantly decreased expression in the hyperresponders (P = .023). Hsa-miR-193b-5p also showed a tendency to be significantly decreased in the hyperresponders (P = .093). In conclusion, our findings provide evidence for altered miRNA expression in granulosa cells of women with ovarian hyperresponse, suggesting a role of miRNAs in regulating ovarian response to gonadotropins.

Differential Expression of microRNAs in the Ovaries from Letrozole-Induced Rat Model of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a complex and heterogeneous endocrine disorder. To understand the pathogenesis of PCOS, we established rat models of PCOS induced by letrozole and employed deep sequencing to screen the differential expression of microRNAs (miRNAs) in PCOS rats and control rats. We observed vaginal smear and detected ovarian pathological alteration and hormone level changes in PCOS rats. Deep sequencing showed that a total of 129 miRNAs were differentially expressed in the ovaries from letrozole-induced rat model compared with the control, including 49 miRNAs upregulated and 80 miRNAs downregulated. Furthermore, the differential expression of miR-201-5p, miR-34b-5p, miR-141-3p, and miR-200a-3p were confirmed by real-time polymerase chain reaction. Bioinformatic analysis revealed that these four miRNAs were predicted to target a large set of genes with different functions. Pathway analysis supported that the miRNAs regulate oocyte meiosis, mitogen-activated protein kinase (MAPK) signaling, phosphoinositide 3-kinase/Akt (PI3K-Akt) signaling, Rap1 signaling, and Notch signaling. These data indicate that miRNAs are differentially expressed in rat PCOS model and the differentially expressed miRNA are involved in the etiology and pathophysiology of PCOS. Our findings will help identify miRNAs as novel diagnostic markers and therapeutic targets for PCOS.

MicroRNA in ovarian function

The mammalian ovary is a dynamic organ. The coordination of follicle recruitment, selection, and ovulation and the timely development and regression of the corpus luteum are essential for a functional ovary and fertility. Deregulation of any of these processes results in ovarian dysfunction and potential infertility. MicroRNA (miRNA) are short noncoding RNA that regulate developmental processes and time-sensitive functions. The expression of miRNA in the ovary varies with cell type, function, and stage of the estrous cycle. miRNA are involved in the formation of primordial follicles, follicular recruitment and selection, follicular atresia, oocyte-cumulus cell interaction, granulosal cell function, and luteinization. miRNA are differentially expressed in luteal cells at the various stages of the estrous cycle and during maternal recognition of pregnancy, suggesting a role in luteal development, maintenance, and regression. An understanding of the patterns of expression and functions of miRNA in the ovary will lead to novel therapeutics to treat ovarian dysfunction and improve fertility and, potentially, to the development of better contraceptives.

MicroRNAs: From Female Fertility, Germ Cells, and Stem Cells to Cancer in Humans

MicroRNAs are a family of naturally occurring small noncoding RNA molecules that play an important regulatory role in gene expression. They are suggested to regulate a large proportion of protein encoding genes by mediating the translational suppression and posttranscriptional control of gene expression. Recent findings show that microRNAs are emerging as important regulators of cellular differentiation and dedifferentiation, and are deeply involved in developmental processes including human preimplantation development. They keep a balance between pluripotency and differentiation in the embryo and embryonic stem cells. Moreover, it became evident that dysregulation of microRNA expression may play a fundamental role in progression and dissemination of different cancers including ovarian cancer. The interest is still increased by the discovery of exosomes, that is, cell-derived vesicles, which can carry different proteins but also microRNAs between different cells and are involved in cell-to-cell communication. MicroRNAs, together with exosomes, have a great potential to be used for prognosis, therapy, and biomarkers of different diseases including infertility. The aim of this review paper is to summarize the existent knowledge on microRNAs related to female fertility and cancer: from primordial germ cells and ovarian function, germinal stem cells, oocytes, and embryos to embryonic stem cells.

miRNA-592 is downregulated and may target LHCGR in polycystic ovary syndrome patients

The polycystic ovary syndrome (PCOS) is an endocrine disorder mainly associated with infertility. Abnormal regulation of relevant genes is required for follicular development in PCOS. In the current study, the expression of serum miRNAs of PCOS patients was explored using miRNA array followed by qRT-PCR assays. The circulating level of miR-592 was significantly down-regulated in PCOS patients in comparison with healthy controls. Furthermore, we found that miR-592 was inversely correlated with the level of luteinizing hormone/chorionic gonadotropin receptor (LHCGR). Computational analysis predicted that miR-592 interacts with the LHCGR mRNA via binding to a site located in the 3'UTR region. Using a luciferase-based reporter assay we found that miR-592 directly targeted the LHCGR. In KGN cell line, miR-592 overexpression inhibited cell viability and the transition of phase G1 to phase S. Knocking down of LHCGR inhibited cell viability and cell cycle progression in KGN cells, and LHCGR co-transfection reversed the inhibitory effect of miR-592. These results shed new light on the diagnosis and treatment of PCOS syndrome.