Long-read sequencing reveals the effect of follicle-stimulating hormone on the mRNA profile of chicken granulosa cells from prehierarchical follicles

Follicle selection is an important step in the laying process of chicken, which is closely related to the laying performance and fecundity of hens. Follicle selection mainly depends on the regulation of follicle -stimulating hormone (FSH) secreted by pituitary gland and the expression of follicle stimulation hor-mone receptor. To uncover the role of FSH in chicken follicle selection, in this study, we analyzed the changes in the mRNA transcriptome profiles of FSH-treated chicken granulosa cells from prehierarchical follicles by long-read sequencing Oxford Nanopore Technologies (ONT) approach. Among the 10,764 genes detected, 31 differentially expressed (DE) transcripts of 28 DE genes were significantly upregulated by FSH treat-ment. These DE transcripts (DETs) were mainly related to the steroid biosynthetic process by GO analysis and enriched in pathways of ovarian steroido-genesis and aldosterone synthesis and secretion by KEGG analysis. Among these genes, the mRNA and protein expression of TNF receptor associated factor 7 (TRAF7) was upregulated after FSH treatment. Fur-ther study revealed that TRAF7 stimulated the mRNA expression of steroidogenic enzymes steroidogenic acute regulatory protein (StAR) and cytochrome P450 fam-ily 11 subfamily A member 1 (CYP11A1) genes and the proliferation of granulosa cells. This is the first study to investigate differences in chicken prehierarchi-cal follicular granulosa cells before and after FSH treat-ment by using ONT transcriptome sequencing, which provides a reference for a more comprehensive under-standing of the molecular mechanism of follicle selec-tion in chicken.

Automated summary

Follicle selection is a crucial process for chicken laying performance and fecundity. In this study, the impacts of follicle-stimulating hormone (FSH) on chicken granulosa cells were investigated through ONT transcriptome sequencing. FSH treatment upregulated the expression of several genes related to steroid biosynthesis and pathways associated with ovarian steroidogenesis. Specifically, TRAF7 was identified as a key regulator in promoting the expression of steroidogenic enzymes and granulosa cell proliferation. This study provides valuable insights into the molecular mechanism of follicle selection in chickens.