Sulforaphane promotes mammary epithelial cell proliferation in Xizang sheep by increasing FOXM1 and PI3K-Akt signaling

Mammary epithelial cells (MECs) are crucial for milk synthesis and secretion, and their abundance and activity directly influence milk yield and quality. This study investigates the effects of sulforaphane (SFN) on MECs isolated from Xizang Sewa sheep. The findings reveal that a 5 μM concentration of SFN promote cell proliferation, enhance DNA synthesis, facilitate the G1/S phase transition, and increase the expression levels of critical cell cycle regulators such as Ki67, PCNA, CDK4, CCNE1, CCNA2, and CCND2. RNA-sequencing analysis further confirms the modulation of numerous genes involved in cell cycle regulation, including FOXM1. Further investigation into FOXM1 demonstrate that its inhibition results in a significant reduction in the mRNA and protein levels of various cell cycle regulatory genes induced by SFN, including Ki67, PCNA, CDK4, and CCNE1. Furthermore, treatment with a PI3K-Akt signaling inhibitor (LY294002) leads to a decrease in PI3K-Akt signaling activity, concomitant with reduced levels of PCNA and FOXM1. However, these effects are ameliorated following SFN treatment. These findings suggest SFN may significantly enhance cell proliferation of MECs in sheep by upregulating FOXM1 expression and activating the PI3K-AKT signaling pathway. This study identifies a promising pharmacological target for augmenting milk production in sheep.