Complete transcriptome analysis of follicular granulosa cells in Kazakh horses of different ages

As an excellent horse breed, Kazakh horses have the characteristics of precocious breeding and seasonal estrus. The normal breeding function is the basis to ensure the breeding and propagation of Kazakh horses, but there is a lack of reproductive function after 14 years old. Based on this research, follicular granulocytes of 1, 2, 7 and 15 years old Kazakh horses were collected for full transcriptome sequencing, and mRNA, LncRNA, miRNA and circRNA of different ages were identified and screened respectively, and GO enrichment analysis was performed. Studies showed that mRNAs, lncRNAs target genes, miRNAs target genes and circRNAs target genes expressed significantly differently in equine egg granulosa cells at different ages, with eca-miR-486-3p and miR-486-y having the highest connectivity. GO, KEGG, PPI and ceRNA regulatory networks indicate that differential target genes are involved in signaling pathways related to cell proliferation, apoptosis and hormone regulation, such as: MAPK signaling pathway, Hippo signaling pathway, Wnt signaling pathway, Calcium signaling pathway, Aldosterone synthesis and secretion, Cellular senescence, NF-kappa B signaling pathway and other signaling pathways related to reproductive process. In order to reveal the molecular mechanism of follicle development in Kazakh horses, this study established and initially verified the lncRNA-miRNA-mRNA differential regulatory network related to cell proliferation, differentiation and apoptosis and involved in stromal follicle development, and laid a theoretical basis for further research on reproductive aging in Kazakh mares.