Mapping the regulatory landscape of sheep pituitary gland associated with puberty at single-cell resolution
The pituitary gland is a remarkably dynamic organ with roles in gonadotropin secretion, and it is composed of numerous cell populations. Defining the roles of pituitary cell in hormone secretion has been challenging, the gene expression patterns of different hormone-producing cells of the pituitary in large animal species are poorly understood, and a cell atlas for ewe is lacking. Single-cell sequencing methods can comprehensively characterize the diversity of pituitary cell types by directly measuring multiple molecular signatures in thousands to millions of individual cells. We created a single-cell transcriptomic atlas of the anterior pituitary gland in ewes at the pre-puberty (3-month-old) and post-puberty (6-month-old) stages, identifying 30,335 cells and ten distinct cell types. The research identified several signaling pathways enriched in different pituitary cells, including the TGFß, SPP1, and NPR2 pathways. Additionally, we isolated and categorized the gonadotropes for further analysis. This allowed us to identify potentially important genes involved in gonadotropin secretion. We also compared pituitary RNA-seq data from four different developmental stages and discovered several genes associated with gonadotropin secretion, including SCG2 and NPW. Besides, in vitro experiments confirmed that SCG2 was predominantly expressed in gonadotropes and promotes the synthesis and secretion of follicle-stimulating hormone. By comparing pituitary data from humans and ewes, we found 79 conserved genes in gonadotrope cells and 479 in immune cells. Our study systematically mapped out the gene expression profile of the anterior pituitary, pinpointing key genes involved in gonadotropin secretion in ewes. Additionally, we created a cell atlas that could provide crucial molecular information for ewes' reproduction. Overall design: Single-cell sequencing of pituitary glands from 3-month-old and 6-month-old Hu sheep