Multiple cell types in the oviduct express the prolactin receptor

Area of Science:

• Reproductive biology
• Endocrinology
• Cell biology

Background:

• The physiological role of prolactin in the oviduct remains largely unknown.
• Prolactin exerts its effects through prolactin receptors (PRLRs), which exist in multiple isoforms.

Purpose of the Study:

• To investigate the expression and localization of prolactin receptor (PRLR) isoforms in the mouse oviduct.
• To determine the functional response of oviductal cells to prolactin.
• To explore the potential impact of prolactin on oviductal function and fertility.

Main Methods:

• Examined mRNA expression of all four PRLR isoforms across different oviduct segments and estrous cycle stages.
• Utilized immunofluorescence to localize PRLR isoforms.
• Assessed cellular response to acute and prolonged prolactin elevation.
• Employed flow cytometry and single-cell RNA sequencing.

Main Results:

• Short form 3 (SF3) was the most highly expressed PRLR isoform, particularly in ciliated areas like the infundibulum.
• PRLR expression and ratios varied by oviduct segment and estrous cycle stage, notably in the infundibulum.
• Ciliated cells in the infundibulum responded to acute prolactin elevation, with evidence of signaling within cilia.
• Prolonged prolactin treatment downregulated genes essential for cilium development and function.
• PRLRs were detected in epithelial cells, with potential roles in smooth muscle and stromal cells.

Conclusions:

• Ciliated oviductal cells are responsive to prolactin, suggesting a role in regulating cyclic changes in infundibular function.
• Hyperprolactinemia may impair ciliated cell function and negatively affect fertility.
• Prolactin likely has diverse roles within the oviduct, involving epithelial, smooth muscle, and stromal cells.