Key Gene and Functional Pathways Identified in Unexplained Recurrent Spontaneous Abortion Using Targeted RNA Sequencing and Clinical Analysis.
Ontology highlight
ABSTRACT: Identifying the mechanisms underlying unexplained recurrent spontaneous abortion (URSA) can help develop effective treatments. This study provides novel insights into the biological characteristics and related pathways of differentially expressed genes (DEGs) in URSA. Nineteen patients with URSA and three healthy fertile women with regular menstruation (control group) were recruited. RNA was extracted from the two groups to determine the differential expression of immunoregulatory gene sequences. Gene ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analyses were used to identify the biological functions and pathways of the identified DEGs. A protein-protein interaction (PPI) network was constructed using the STRING database. Furthermore, qRT-PCR and ELISA were performed to validate the differential expression of the hub genes. We also explored the regulatory mechanism of Th1/Th2 imbalance. A total of 99 DEGs were identified, comprising 94 upregulated and five downregulated genes. Through GO analysis, nine immune cell function-related clusters were selected, and genes with significant differential expression were primarily enriched in eight immune regulatory functions related to the KEGG signalling pathway. Subsequently, five hub genes (TLR2, CXCL8, IFNG, IL2RA, and ITGAX) were identified using Cytoscape software; qRT-PCR confirmed the differential expression among the hub genes, whereas ELISA revealed a significant difference in extracellular IFN-γ and IL-8 levels. The levels of Th1 (IFN-γ) and the Th1/Th2 ratio were higher in the peripheral blood of URSA patients than in control group patients. These findings suggest that the occurrence of URSA may be associated with the abnormal expression of some specific immunoregulatory genes involved in T-cell activation and differentiation. Among the identified DEGs, IFNG may play a key role in regulating maternal immune response. Although further validation is required, our data provide an important theoretical basis for elucidating the pathogenesis of recurrent spontaneous abortion.
Project description:BackgroundRecurrent spontaneous abortion (RSA) is one of the common complication of pregnancy, bringing heavy burden to the patients and their families. The study aimed to explore the lncRNA-miRNA-mRNA network associated with recurrent spontaneous abortion.MethodsBy transcriptome sequencing, we detected differences in lncRNA, miRNA and mRNA expression in villus tissue samples collected from 3 patients with RSA and 3 normal abortion patients. Differentially expressed lncRNAs, miRNAs and genes (DELs, DEMs and DEGs, respectively) were identified, and Geno Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to determine the functions of DELs and DEGs, which were analysed by Fisher's test. We also observed the regulatory relationships between miRNA-mRNA and lncRNA-miRNA by Cytoscape 3.6.1.ResultsThe results showed that 1008 DELs (523 upregulated and 485 downregulated), 475 DEGs (201 upregulated and 274 downregulated) and 37 DEMs (15 upregulated and 22 downregulated) were identified. And we also constructed a novel lncRNA-related ceRNA network containing 31 lncRNAs, 1 miRNA (hsa-miR-210-5p) and 3 genes (NTNG2, GRIA1 and AQP1).ConclusionslncRNA-related ceRNA network containing 31 lncRNAs, 1 miRNA (hsa-miR-210-5p) and 3 mRNAs (NTNG2, GRIA1 and AQP1) was constructed. The results may provide a basic theory for elucidating the mechanism underlying RSA.
Project description:BackgroundThe precise etiology of approximately 50% of patients with recurrent spontaneous abortion (RSA) is unclear, known as unexplained recurrent spontaneous abortion (URSA). This study identified the genetic polymorphisms in patients with URSA.MethodsGenomic DNA was extracted from 30 couples with URSA and 9 couples with normal reproductive history for whole exome sequencing. Variations in annotation, filtering, and prediction of harmfulness and pathogenicity were examined. Furthermore, predictions of the effects of changes in protein structure, Sanger validation, and functional enrichment analyses were performed. The missense mutated genes with significant changes in protein function, and genes with mutations of premature stop, splice site, frameshift, and in-frame indel were selected as candidate mutated genes related to URSA.ResultsIn 30 unrelated couples with URSA, 50%, 20%, and 30% had 2, 3, and more than 4 miscarriages, respectively. Totally, 971 maternal and 954 paternal mutations were found to be pathogenic or possibly pathogenic after preliminary filtering. Total variations were not associated with age nor the number of miscarriages. In 28 patients (involving 23 couples), 22 pathogenic or possibly pathogenic variants of 19 genes were found to be strongly associated with URSA, with an abnormality rate of 76.67%. Among these, 12 missense variants showed obvious changes in protein functions, including ANXA5 (c.949G>C; p.G317R), APP (c.1530G>C; p.K510N), DNMT1 (c.2626G>A; p.G876R), FN1 (c.5621T>C; p.M1874T), MSH2 (c.1168G>A; p.L390F), THBS1 (c.2099A>G; p.N700S), KDR (c.2440G>A; p.D814N), POLR2B (c.406G>T; p.G136C), ITGB1 (c.655T>C; p.Y219H), PLK1 (c.1210G>T; p.A404S), COL4A2 (c.4808 A>C; p.H1603P), and LAMA4 (c.3158A>G; p.D1053G). Six other genes with mutations of premature stop, splice site, frameshift, and in-frame indel were also identified, including BUB1B (c.1648C>T; p.R550*) and MMP2 (c.1462_1464delTTC; p.F488del) from the father, and mutations from mother and/or father including BPTF (c.396_398delGGA; p.E138 del and c.429_431GGA; p.E148del), MECP2 (c.21_23delCGC; p.A7del), LAMA2 (HGVS: NA; Exon: NA; SPLICE_SITE, DONOR), and SOX21 (c.640 _641insT; p. A214fs, c.644dupC; p. A215fs and c.644_645ins ACGCGTCTTCTTCCCGCAGTC; p. A215dup).ConclusionsThese pathogenic or potentially pathogenic mutated genes may be potential biomarkers for URSA and may play an auxiliary role in the treatment of URSA.
Project description:Recurrent spontaneous abortion (RSA), defined as the failure of two or more consecutive clinical pregnancies before 20 weeks of gestation, affects approximately 1% of couples attempting to conceive. However, the underlying mechanisms of 50% of cases are unknown. The villus plays a crucial role during pregnancy, which can provide a delicate balance between immune tolerance and defense to maintain the pregnancy.We performed RNA-seq to identify gene expression alterations in the villus of RSA patients and controls. RNA-seq was done using TruSeq Stranded mRNA Library Preparation. Briefly, intact RNA was fragmented, end repaired, adapter ligation and PCR amplified following illumina protocol. Libraries were sequencing by illumins Hiseq 2000. After quality control, sequence data were processed with STAR to generate read alignments with hg19. Raw read counts for annotated genes were obtained with featureCounts with default settings, normalized and analyzed using DEseq2.
Project description:Recurrent spontaneous abortion (RSA), defined as the failure of two or more consecutive clinical pregnancies before 20 weeks of gestation, affects approximately 1% of couples attempting to conceive. However, the underlying mechanisms of 50% of cases are unknown. The decidua plays a crucial role during pregnancy, which can provide a delicate balance between immune tolerance and defense to maintain the pregnancy.We performed RNA-seq to identify gene expression alterations in the deciduas of RSA patients and controls. RNA-seq was done using TruSeq Stranded mRNA Library Preparation. Briefly, intact RNA was fragmented, end repaired, adapter ligation and PCR amplified following illumina protocol. Libraries were sequencing by illumins Hiseq 2000. After quality control, sequence data were processed with STAR to generate read alignments with hg19. Raw read counts for annotated genes were obtained with featureCounts with default settings, normalized and analyzed using DEseq2.
Project description:BackgroundUnexplained recurrent spontaneous abortion (URSA) is one of the most challenging conditions frustrates women of childbearing age profoundly. The gene expression patterns and biological characteristics of placental villus in patients with URSA remain largely unknown. The aim of our study was to identify potential lncRNAs as well as their action mechanisms in URSA.MethodThe ceRNA microarray was used to identify the mRNA and lncRNA expression profiles of URSA patients and normal pregnancy. Functional enrichment analyses for differentially expressed mRNAs in URSA were performed. Protein-protein interaction analysis of differentially expressed mRNAs was performed to identify hub genes and key modules. Subsequently, the co-dysregulated ceRNA network of URSA was established, and the enrichment analyses for the mRNAs in the ceRNA network was implemented. qRT-PCR was performed to validated the expression of key ENST00000429019 and mRNAs in URSA.ResultsWe found that URSA placental villus have distinct mRNA and lncRNA expression profiles through ceRNA microarray, with a total of 347 mRNAs and 361 lncRNAs differentially expressed compared with controls. The functional enrichment analysis revealed that ncRNA processing, DNA replication, cell cycle, apoptosis, cytokine-mediated signaling pathway, ECM-receptor interaction were the potentially disrupted pathways in URSA patients. Then we constructed a co-dysregulated ceRNA network and found differentially expressed mRNAs were regulated by a small fraction of hub lncRNAs. Finally, we found a key network of ENST00000429019 and three cell proliferation or apoptosis related key mRNAs (CDCA3, KIFC1, NCAPH), and validated their expression and regulation in tissue and cellular levels.ConclusionsThis study identified a key ceRNA network, which might take part in URSA and correlate with cell proliferation and apoptosis. Optimistically, this study may deepen our apprehensions about the underlying molecular and biological causes of URSA and provide an important theoretical basis for future therapeutic strategies for patients with URSA.
Project description:Human leukocyte antigen-E (HLA-E)is a non-classical major histocompatibility complex (MHC) class I antigens which expressed on extra villous cytotrophoblast, which interacts with NKG2A, is an inhibitory receptor on natural killer (NK) cells and leading to down regulation of immune response in the maternal-fetal interface and provides maternal immune tolerance of the fetus.This study was designated to investigate the gene frequencies of E0101 and E0103 in HLA-E gene in Iranian women with recurrent spontaneous abortion (RSA).Amplification Refractory Mutation System (ARMS-PCR) technique was carried out to detect polymorphism in exon 3 of the HLA-E gene in women with RSA and controls (n=200). Differences between groups were analyzed by SPSS19 software using (2) test.There was no significant difference in the allele frequencies of the HLA-E polymorphism between RSA and fertile controls but HLA-E 0101/0103 heterozygous genotype was found to be significantly higher in RSA group (p=0.006, OR=1.73), so this genotype might confer susceptibility to RSA.Our results suggest that HLA-E 0101/0103 heterozygous genotype leads to increase of RSA risk. It seems that by genotyping of HLA-E polymorphism, we can predict the risk of RSA in infertile women.
Project description:BACKGROUND:Recurrent Spontaneous Abortion (RSA) is caused by multiple genetic and non-genetic factors. Around 50% of the RSA cases have no known etiology and are considered as Unexplained RSA (URSA). Estrogens, via binding to their receptors, play an important role in female reproduction. This study aimed to investigate whether single nucleotide polymorphisms (SNPs; +1082G/A, +1730G/A and rs1256030 C/T) in the estrogen receptor beta (ESR2) gene are associated with susceptibility to URSA in a population of Iranian women. METHODS:In this case-control study, the study groups consisted of 240 subjects with a history of URSA and 102 fertile women as controls. Serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were measured on day 2-3 of menstrual cycle. Two functional SNPs, +1082G/A (a silent mutation in exon 5) and +1730G/A (3' untranslated region of the exon 8), and one intron, rs1256030C/T, in the ESR2 gene were genotyped, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS:Serum levels of LH were significantly increased in URSA women. No significant differences in distribution of +1082G/A, +1730G/A and rs1256030C/T between URSA and control groups were observed. CONCLUSION:Our findings suggest that the studied SNPs on ESR2 gene may not be associated with URSA.
Project description:Unexplained recurrent spontaneous abortion (URSA) is one of the most intractable clinical challenges in reproduction. As a specific type of endogenous non-coding RNA, circular RNAs (circRNAs) have great pre-clinical diagnostic and therapeutic values in diseases. Recently, thousands of circRNAs were detected in human pre-implantation embryos, indicating that circRNAs potentially have important regulatory functions. However, the roles of circRNAs in URSA remain largely unknown. In this study, we elucidated deregulated circRNA expression and distinct competing endogenous RNA (ceRNA) networks by comparing URSA placental villus with that of patients with normal pregnancy using microarrays. We characterized a distinct circRNA, circRNA-0050703, which is downregulated in URSA placental villus (thus we named it circRNA-DURSA). Silencing of circRNA-DURSA results in trophoblast cell apoptosis in vitro. Furthermore, mechanistic dissection revealed that circRNA-DURSA exerts its effects by competitively binding to miR-760, which post-transcriptionally targets HIST1H2BE. Additionally, after circRNA-DURSA silencing in vivo, the numbers of implanted embryos decreased significantly. These results reveal the regulatory roles of circRNA-DURSA in trophoblasts and identified a distinct circRNA-DURSA/miR-760/HIST1H2BE axis as potentially important diagnostic and therapeutic targets for URSA treatment.
Project description:Currently, the precise causes of over 40 % of recurrent spontaneous abortion (RSA) cases cannot be identified, leading to the term "unexplained RSA" (URSA). Through an exploration of the gut microbiota, metabolites, and immune cell subsets in URSA, this study establishes a link between gut microbiota-derived metabolites and immune cells. The results indicate reduced diversity in the gut microbiota of URSA. Targeted metabolomic analyses reveal decreased levels of gut microbiota-derived deoxycholic acid (DCA), glycolithocholic acid (GLCA), acetate, propionate, and butyrate in URSA. Furthermore, elevated frequencies of Th1, Th17, and plasma B cells, along with decreased frequencies of Tregs and Bregs, are observed in the peripheral blood of URSA. The results demonstrate correlations between the levels of gut microbiota-derived bile acids and short-chain fatty acids and the frequencies of various immune cell subsets in circulation. Collectively, this study uncovers an association between gut microbiota-derived metabolites and circulating immune cell subsets in URSA.
Project description:BackgroundMaternally Expressed Gene 3 (MEG3) is expressed at low levels in placental villi during preeclampsia; however, its roles in unexplained recurrent spontaneous abortion (URSA) remain unclear. In this study, we aimed to explore the relationship between MEG3 and URSA.MethodsThe differentially expressed lncRNAs (MEG3) and its downstream genes (RASA1) were identified using bioinformatics analysis of Genomic Spatial Event (GSE) database. The expression levels of MEG3 in embryonic villis (with gestational ages of 49-63 days) and primary trophoblasts were determined using quantitative RT-PCR assay. A mouse model of Embryo implantation, Cell Counting Kit-8 (CCK-8), flow cytometry, and Transwell migration assays were performed to determine the implantation, proliferative, apoptotic, and invasive capacities of trophoblast. The level of phosphorylated core proteins in the RAS-MAPK pathway were analyzed using Western blot assay. The mechanisms of MEG3 in the regulation of RASA1 were studied by RNA pulldown, RNA immunoprecipitation (RIP), DNA pulldown, and chromatin immunoprecipitation (ChIP) assays.ResultsMEG3 had a low expression level in embryonic villis of 102 URSA patients compared with those of 102 normal pregnant women. MEG3 could promote proliferation and invasion, inhibit the apoptosis of primary trophoblast of URSA patients (PT-U cells), as well as promote embryo implantation of mouse. Besides, MEG3 also promoted the phosphorylation of rapidly accelerated fibrosarcoma (Raf), mitogen-activated protein kinase kinase (MEK), and extracellular-signal-regulated kinase (ERK) proteins. The results of RNA pull down and RIP assays showed that MEG3 bound with the enhancer of zeste homolog 2 (EZH2). The DNA pulldown assay revealed that MEG3 could bind to the promoter sequence of the RAS P21 Protein Activator 1 (RASA1) gene. Further, the ChIP assay showed that MEG3 promoted the binding of EZH2 to the promoter region of the RASA1 gene.ConclusionsThe inactivation of MEG3 in embryonic villi association with URSA; MEG3 inhibited the expression of RASA1 by mediating the histone methylation of the promoter of RASA1 gene by EZH2, thereby activating the RAS-MAPK pathway and enhancing the proliferative and invasive capacities of trophoblasts.