Study On The Mechanism Of FASN Regulating Thefunction Of Goose Follicular Granulosa Cells

Fatty acid synthase(FASN)plays a key role in lipid metabolism.FASN can affect the development of ovarian follicles and the reproductive performance of animals by regulating the function of granulosa cells(GCs).However,the molecular mechanism by which FASN regulates GCs function remains unclear.In this study,goose GCs were used as the experimental object to explore the difference of FASN on the function of pre-hierarchical follicles granulosa cells(ph GCs)and hierarchical follicles granulosa cells(h GCs)by using overexpression and interference techniques,and to clarify the molecular mechanism by using combined analysis of transcriptome and metabolome.The main results were as follows:1.The results of physiological function test showed that,FASN overexpression increased the expression levels of SCD1,DGAT2,APOB and the lipid deposition in h GCs,and promoted the apoptosis of ph GCs and h GCs.FASN interference inhibited the expression levels of CPT-1,St AR and the synthesis of progesterone,and increased the lipid deposition both in ph GCs and h GCs.2.Metabolome test analysis showed that 63 and 54 differential metabolites were screened from ph GCs and h GCs after treating with FASN overexpression,respectively;after interfering with FASN,36 and 35 differential metabolites were screened from ph GCs and h GCs respectively.And FASN interference increased the content of 5-Hydroxytryptamine(5-HT)in h GCs supernatant;and FASN overexpression increased the content of 5-Hydroxytryptophol(the metabolites of 5-HT)in ph GCs supernatant.3.RNA-seq analysis showed that 1099 and 591 DEGs were screened from ph GCs and h GCs respectively after treating with FASN overexpression;after interfering with FASN,224 and 161 DEGs were screened from ph GCs and h GCs respectively.After treating with FASN overexpression,the KEGG pathways enriched by DEGs in ph GCs and h GCs were relatively consistent,and most of them were related to immunity and necroptosis,especially the tolllike receptorsignal pathway.The hub genes screened were IRF7,STAT1 and TLR3.FASN overexpression could promote proinflammatory factors expression by activating TLR3 /IRF7 and TLR3 / NF-κB signal pathways in ph GCs,and only by activating TLR3 / IRF7 signal pathways in h GCs.And then these proinflammatory factors could induce necroptosis of goose GCs by activating JAK / STAT1 signaling pathway.In addition,FASN overexpression also induced apoptosis of goose GCs by activating the BAK / CASP7 signaling pathway.4.The combined analysis of metabolome and transcriptome revealed that FASN affected demand of the 5-HT for ph GCs by activating the neuroactive ligand-receptor interaction pathway to regulate the expression of HTRs or activating the metabolism of tryptophan;but only affected the demand of 5-HT for h GCs by activating the neuroactive ligand-receptor interaction pathway to regulate the expression of HTRs,and ultimately affected the physiological function of goose GCs.In conclusion,this study showed that there were some differences in the mechanism of FASN regulating the physiological function of goose ph GCs and h GCs.The results provided a theoretical basis for further analyzing the mechanism of lipid metabolism involved in the regulation of GCs function and follicular development in goose.