Single-Cell RNA Sequencing Uncovers Macrophage-Granulosa Cell Crosstalk and Its Role in Regulating Follicle Development in Sheep
Macrophages, as key immune cells in the ovarian stroma, play a pivotal role in regulating ovarian function and follicle development. In this study, we employed single-cell RNA sequencing to elucidate the complex communication between macrophages and granulosa cells, as well as its impact on follicle in development sheep ovaries, with a focus on comparing Hu sheep (HU, high prolificacy breed) with Mongolian sheep (MG, low prolificacy breed). We identified 8 major cell clusters. Importantly, we found that the number of granulosa cells and macrophage were different between two groups. Our analysis also revealed the interaction number of macrophage and granulosa cells were higher in HU sheep. furthermore, we collect a list of transcription factors between two groups, including SOX4, FLI1, FOXO1 and others. Notably, the expression level of IGFBP2 in HU group was significantly upregulated in granulosa cells and macrophage, compared with MG group. Furthermore, we applied co-culture system and found IGFBP2 knockdown in vitro sheep macrophages led to a significant increase in PCNA expression in granulosa cells. In conclusion, this study provides valuable insights into the intercellular communication between macrophages and granulosa cells in the ovarian microenvironment and provides novel insights into their regulatory mechanisms underlying ewe reproductive capacity.