Work

Time-resolved transcriptomic profiling of mammary gland tissue during ductal morphogenesis, lactation activation, and involution in sows

Year: 2025

Type: article

Abstract: OBJECTIVE: Mammary development and lactation are vital for piglet survival, but gene expression profiles from gestation to early involution (W2) in sows remain unclear. This study profiles key transcriptomic changes to reveal molecular features. METHODS: Mammary gland tissue samples were collected from hybrid half-sibling sows (Danish Landrace×Yorkshire) at five physiological stages: mid-gestation (MG), late gestation (LG), early lactation (EL), peak lactation (PL), and W2 (day 2 after weaning). Transcriptome sequencing (RNA-seq) was performed on 30 samples (n = 6 per stage). Differential expression analysis and clustering were conducted to identify expression patterns. Functional enrichment, pathway analysis, and weighted gene co-expression network analysis (WGCNA) were used to identify stage-specific regulatory networks and hub genes involved in mammary gland development, metabolism, immune response, and structural remodeling. RESULTS: Transcriptome profiling yielded over 61,000 expressed transcripts, with 27,244 shared across all stages. A total of 12,239 transcripts were differentially expressed, with the greatest transcriptomic shift occurring between PL and W2 (4,829 differentially expressed transcript [DETs]). DETs were grouped into five expression clusters, each showing stagespecific enrichment in biological processes. W2-associated transcripts were enriched in pathways related to cell junction integrity and apoptosis, while MG and LG stages were associated with proliferation and metabolic pathways. EL and PL stages showed enrichment in immune and lipid metabolism pathways. WGCNA identified nine gene modules, with modules linked to gestational growth (brown, blue), lactation (green, turquoise), and involution (yellow, turquoise). Key regulatory genes such as EGF, AKT1, SRC, GATA3, STAT6, TNFSF11, and NFKB1 were identified as central hubs within six major functional networks. CONCLUSION: This study constructed a time-resolved transcriptomic atlas of porcine mammary gland development, lactation, and involution. It reveals gene expression dynamics, identifies candidate pathways, and delineates molecular signatures associated with structural and functional changes in the mammary gland. The findings offer potential targets and a theoretical framework for improving sow lactation performance and regulating mammary function.

Source: Animal Bioscience

DOI: 10.5713/ab.250560