Comparative analysis of PI3K-AKT and MEK-ERK1/2 signaling-driven molecular changes in granulosa cells

The PI3K-AKT and MEK-ERK signaling pathways are integral to fundamental cellular processes such as proliferation, viability, and differentiation. In granulosa cells (GCs), these pathways are activated by FSH and IGF1 through respective receptors. We investigated the comparative transcriptome changes induced by AKT and ERK pathways using corresponding inhibitors in GCs. GCs isolated from antral follicles showed positive signals for phospho-AKT and -ERK proteins. Treatment of cultured GCs with FSH and IGF1 induced phospho-AKT and -ERK levels. Transcriptome analysis revealed 1436 genes regulated by AKT and 654 genes regulated by ERK pathway. Among these, 94 genes were commonly downregulated, and 11 genes were commonly upregulated in both data sets, while 110 genes were oppositely regulated. Bioinformatics analysis revealed that inhibition of PI3K-AKT and MEK-ERK pathways downregulates key reproductive processes and upstream molecules. Notably, AKT inhibition affected FSH, ESRRG, and HIF1 pathways, while ERK inhibition impacted CG, FOS, TGFβ, EGR1, and LH pathways. Transcriptome data showed that genes related to estradiol production were inhibited by ERK and induced by the AKT pathway. This was verified by radioimmunoassays, and mRNA and protein analysis of CYP19A1 and STAR genes. In addition, transcriptome data suggested downregulation of glucose metabolism in GCs. Using validation experiments, we confirm that both pathways are essential for glucose uptake, lactate production, and mitochondrial activity in GCs. These data provide a resource for informing future research for analyzing various novel candidate genes regulated by AKT and ERK pathways in GCs and other cell types.