The Identification And Functional Analysis Of Circrnas In Endometrial Receptivity Of Mice With Polycystic Ovary Syndrome
Authors: Zhao Zi-wei , Li Da-wei , Wang Nan , Xu Li , Weng Yu-jing , Pan Yan-ping , Mao Cai-ping , Zhou Wei-qin 
Published: March 2022

Abstract
Background: The disorders of endometrial receptivity and ovulatory dysfunction are both important causes of infertility of patients with Polycystic Ovary Syndrome(PCOS) .The study aimed to investigate the expression profile and functional analysis of circRNAs in the endometrial receptivity of mice with PCOS. Methods: Twenty-four 4-week-old female C57BL/6 mice were randomly divided into two groups(PCOS group and Normal control group,n=12) and PCOS group was subcutaneously with DHEA 6mg/kg for 20 days.The circRNA expression profile in the endometrium tissue of two groups on the 4th day of gestation was screened by gene chip technique.Bioinformatics analyses, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were performed to preliminary understand the functions of circRNAs. The expression of selected circRNA was verified by RT-PCR and and circRNA–microRNA(miRNA)–messenger RNA (mRNA) negative correlation network analyses was construct by Cytoscape.Result: Compared with mice in NC group,there are 205 differentially expressed circRNAs significantly in mice of PCOS group,including 147 up-regulated and 58 down-regulated circRNAs(fold change [FC]≥1.5 and p value < 0.05). GO analysis demonstrated that the host genes of differentially regulated circRNAs were mainly related to protein binding,cellular process and cellular anatomical entity.KEGG analysis revealed that these source genes were engaged in the Proteoglycans in cancer,Cell junctions (focal adheren and gap junction) ,Pathways in cancer,Ras signaling pathway,Chemokine signaling pathway，autophagy and PI3K-Akt signaling pathway.qRT-PCR results showed that the expression levels of circRNA_38548 (P<0.05), circRNA_001686(P<0.05) and circRNA_38550(P<0.01) in PCOS group were significantly higher than those in normal group,while the expression level of circRNA_27938 in PCOS group was significantly lower than that in control group (P<0.05). The expression of circRNA_29710 (P=0.051) and circRNA_34429 (P=0.892) showed no significant difference between the two groups.We used target prediction software(TargetScan and miRanda) to predict the target genes of circRNA_38548, circRNA_001686, circRNA_38550 and circRNA_27938.The circRNA-miRNA-mRNA regulatory network diagram was constructed using Cytoscape software,involving 4 circRNAs (circRNA_38548, circRNA_38550, circRNA_001686, circRNA_27938) and 17miRNAs (miR-214-3p,miR-532-5p and miR-432,etc.) and 136mRNAs(Lifr, FOXK1, FOXO1, HOXA10, etc.). Conclusions: The circRNAs were aberrantly expressed in the implantation window of PCOS mice,suggesting that differentially expressed circRNA may play a role in the endometrial receptivity of PCOS. We validated four circRNAs(circRNA_38548, circRNA_38550, circRNA_001686 and circRNA_27938),which may contribute to the abnormal endometrial receptivity of PCOS by regulating the expression of Lifr, FOXK1, FOXO1, HOXA10 and other genes through targeting mir-214-3p, mir-532-5p, mir-423 and other miRNAs. These four circRNAs are worthy targets for further study of the related mechanisms.