The key role of acss1 in mammary gland development and lactation: a study based on gene co-expression network analysis.

BACKGROUND: Lactation physiological activity plays a key role in maternal health as well as infant nutrition and growth. The complex gene regulatory networks of lactation remain largely unexplored during mammary gland development. A deeper understanding of these processes is essential for identifying potential therapeutic targets to improve lactation efficiency. METHODS: We employed Gene Co-expression Network Analysis (WGCNA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis to identify the gene expression patterns, regulatory mechanisms and cellular signaling pathways involved in mammary gland development during pregnancy and lactation. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate gene expression in mRNA levels at different stages of mammary development. Immunohistochemical staining was carried out to detect the protein level of ACSS1 at different stages of mammary development. Lactogenic differentiation assay and triglyceride (TAG) secretion detection were applied to investigate the effect of Acss1 on lactogenic differentiation and milk lipid metabolism during lactation. RESULTS: We identified 23 gene modules, among which 8 modules were activated during pregnancy and lactation stage of mammary gland development. Cellular signaling pathways associated with mammary gland differentiation were enriched, including the FOXO and Wnt signaling pathways during pregnancy, as well as steroid biosynthesis and fatty acid metabolism during lactation. Among the identified genes, Acss1 emerged as a potential hub gene within module 8, exhibiting high connectivity with 312 other genes, and playing a critical role in lactogenic differentiation and milk lipid metabolism. Experimental validation showed that the gene expression pattern of Acss1 were highly consistent with microarray data at different stages of mammary gland development. Lactogenic differentiation assay and TAG secretion detection showed that Acss1 is crucial for lactogenic differentiation and affects the production and secretion of TAG during lactation in vitro. CONCLUSION: These findings suggesting Acss1 as a potential key regulatory factor of lactation efficiency.