Omics analysis combined with experiments provides insights into ovulation

Running title: More insights into ovulation Purpose:Ovulation is the process by which mature follicles release fertilized oocytes under the stimulation of gonadotropin. This involves the precise interaction and destiny of various cells in the follicle. Granulosa cells (GCs) are the only cells that recognize and respond to ovulation LH (or HCG) signals. Therefore, the classification and deep interpretation of genes in GCs under LH surge stimulation is the key to understand ovulation. Methods: In this study, RNA-seq, Q-PCR, Western blot, gene knockout, gene knockout and other experimental techniques were used to conduct trend and classification analysis of the genes regulated by ovulation signal of LH at the cellular and individual levels. Genes that may be involved in ovulation were screened, identified and were selected for functional verification. Results:(1) Firstly, 7104 and 347 mRNA and Long noncoding RNA (LncRNA) that may be involved in ovulation activity were screened at the gene level by transcriptome sequencing technology, respectively. According to gene expression, they were divided into activated, inhibited and transient activated gene expression patterns. 44 secreted proteins, 62 transcription factors, 22 periodic expression characteristic genes, 10 ovulation process unknown genes, 16 LncRNA-target gene cis pair combinations and 41 highly expressed LncRNA were identified and listed in the three models;(2) The functions of LncRNA Gm12840 and Gm20186 were studied at the cellular level. The results showed that knockdown Gm12840/20186 not only inhibited the proliferation and hormone synthesis of GCs, but also induced cell apoptosis;(3) The function of LncRNA Gm12840 was further studied in mice, and Gm12840 knockout mice were constructed by CRISPR/CAS9 technology: Results It was found that Gm12840 knockout significantly increased the number of antral follicles and ovulation, and significantly inhibited the number of atretic follicles and antral follicles not discharged after ovulation. Gm12840 knockout significantly increased litter size at 2-3 months of age, but also significantly inhibited litter size at 7-9 months of age. Meanwhile, Gm12840 knockout also significantly inhibited the number of follicles growing in the ovary of 11-month-old mice;(4) Finally, transcriptomic sequencing analysis of wilt-type and Gm12840-/- mouse GCs showed 349 genes were differentially expressed. KEGG enrichment analysis and WB results showed that Gm12840 knockout enhanced mTOR and MAPK signals. Conclusions:The above results screened and identified genes with potential research value during ovulation process, and took LncRNA Gm12840 as an example to verify their functions at the cell and individual levels, providing reference for further revealing the ovulation process.