A Study On Regional Differences In Decidualization Of The Mouse Uterus By Using RNA-seq

Endometrial stromal cells undergo decidualization,which is an important process for the establishment and maintenance of human pregnancy.During this process,cells differentiate into large epithelioid cells characterized by the secretion of decidual prolactin(dPRL)and insulin-like growth factor binding protein 1(IGFBP1).Although regional differences have been recognized for decades in the decidualization process of mouse,the molecular mechanisms remain under-studied.In this study,we used natural pregnancy and artificial decidualization models in mice to study the regional differences in the decidualization.The anti-mesometrial(AM)region tissue and the mesometrial(M)region tissue of uterus were dissected and subjected to RNA-seq analysis.We identified a total of 1423 differentially expressed genes in the natural pregnancy model,of which 811 is AM-enriched and 612 is M-enriched.There were2328 differentially expressed genes in the artificial decidualization model,of which 1206 is AM-enriched and 1122 is M-enriched.To validate the RNA-seq data,a total of 16 genes with various fold changes were selected and validated by qRT-PCR(quantitative reverse transcription-polymerase chain reaction).The expression patterns were coincident between these two techniques,indicating a high quality of our RNA-seq data.In order to further understand differentially expressed genes,we performed Gene Ontology(GO)analysis,KEGG pathway analysis,network analysis and transcription factor binding site analysis,respectively.GO analysis showed that AM-enriched(anti-mesometrial enriched)genes were generally involved in cell metabolism and differentiation,whereas M-enriched(mesometrial enriched)genes were associated with immune response.In addition to GO analysis,KEGG pathway analysis also confirmed that genes selectively enriched in these two compartments were functionally different.Based on the result of gene network analysis,4 hub genes(Plcb1,Kng1,Kng2 and Rhoc)were identified among AM-enriched genes and 2 hub genes(Vav1 and Gng2)were identified among M-enriched genes in the natural pregnancy model.In the artificial decidualization model,we discovered5 hub genes(App,Kng2,Kng1,Plcb1 and Bdkrb2)among AM-enriched genes and 19 hubgenes(Cdc20,Ndc80,Ccnb1,Aurkb,Birc5,Mad2l1,Top2 a,Bub1b,Cdca8,Cdca5,Kif11,Aurka,Nuf2,Cdk1,Bub1,Cenpf,Cenpe,Mcm5 and Incenp)among M-enriched genes.These genes represent functionally important genes due to their key positions in the networks and thus deserve further investigation.Based on the result of transcription factor binding sites analysis,SREBP-1,NF-kappaB,STAT6,MAZ,CAC-BP and LBP-1 were significantly over-represented in AM-enriched genes and SREBP-1 is significantly over-represented in M-enriched genes in the natural pregnancy model.In the artificial decidualization model,AP-2gamma were significantly over-represented in AM-enriched genes,whereas AP-2gamma and MAZ were significantly over-represented in the M-enriched genes.In summary,we determined the differentially expressed genes related the regional differences in decidualization process of the mouse uterus by using RNA-seq.By using bioinformatic analysis,we confirmed that decidualization in the anti-mesometrial region is involved in the accommodation of embryo implantation and decidualization in the mesometrial region contributes to the preparation of placentation.Our study contributes to an increase in the knowledge on the molecular mechanisms underlying regional decidualization in mice.