Deciphering Cellular Heterogeneity and Communication Patterns in Porcine Antral Follicles by Single-Cell RNA Sequencing

SIMPLE SUMMARY: Oocytes are the foundation of life in mammals. They develop in small sacs called follicles in the ovaries. Each follicle holds one oocyte and numerous accompanying cells, and the final stage of oocyte development happens in a follicle called the antral follicle. The successful growth and maturation of oocytes depend on complex interactions with neighboring cells, mainly granulosa cells. Understanding the differences among these granulosa cells within the antral follicle and how they communicate with each other is essential for comprehending how mammals reproduce and grow. In this study, we collected cells from these follicles in pigs and utilized single-cell RNA sequencing to profile the transcriptomic features of these cells. The study discovered diverse subpopulations of granulosa cells within antral follicles, and they were found to communicate extensively. These findings provide us with valuable insights into how follicles develop and oocytes mature in pigs. This could potentially help improve pig reproduction efficacy and advance our knowledge in human reproductive medicine. ABSTRACT: The antral follicle stage is a critical period in mammalian oocyte maturation, marked by complex interactions between oocyte development and neighboring granulosa cells. Understanding the heterogeneity and communication patterns of granulosa cells within antral follicles is crucial for deciphering their roles in follicle development and oocyte maturation. Here, we employed single-cell RNA-sequencing to explore the molecular and cellular characteristics of porcine antral follicles. Our analysis revealed distinct subpopulations within mural and cumulus granulosa cells, indicating diverse cellular states and functions within the follicles. Functional enrichment analysis unveiled the involvement of specific subpopulations in steroid biosynthesis, cumulus expansion, and cellular communication. Moreover, comparing mature and less mature follicles highlighted differences in cell distribution and functions, indicating developmental-specific variations. Our findings shed light on the intricate cellular heterogeneity and communication network within porcine antral follicles, providing valuable insights into the regulation of follicle development and oocyte maturation in pigs. These results hold promise for improving pig reproductive efficiency and advancing human reproductive medicine.