Alterations in steroid hormone receptors, angiogenetic, cell proliferation, apoptotic, and Ras-related factors during estrous cycle in porcine corpus luteum

This study aimed to examine the association of Ras signaling with steroid hormone receptors, angiogenic factors, cell cycle/cell proliferation markers, and apoptotic factors during the estrous cycle in pigs. Porcine corpus luteum (CL) tissues were classified into the early (EP), middle (MP), and late phases (LP). Furthermore, the mRNA and protein expression profiles of steroid hormone receptors, angiogenic factors, cell cycle-related factors, apoptosis-related factors, Ras and Ras GTPases were assessed using reverse transcription-polymerase chain reaction, western blot, and protein–protein interaction. The CL showed the highest tissue weight in the MP. At the mRNA level, 3β-HSD and P4R were substantially increased at MP, and PGF2αR was markedly elevated at LP. At the protein level, 3β-HSD was the highest at MP, P4R was increased at EP, and PGF2αR was the highest at LP. For angiogenic factors, angiopoietin 1 and Tie2 mRNA levels were increased in MP, vascular endothelial growth factor D protein levels were increased in MP, and angiopoietin 4 protein levels were increased in EP. Cell cycle factors revealed increased extracellular signal-regulated kinase 1, cyclin dependent kinase 1, and cyclin B1 mRNA expression in MP, whereas CCNB1 protein expression increased in EP. tumor necrosis factor receptor 1 mRNA was the highest in LP, Bax and caspase 3 mRNA increased in the MP group, and Bcl2 mRNA increased at EP. At the protein level, Casp3 was markedly increased in LP. Additionally, the Ras family and Ras GTPases showed stage-dependent expression alterations at the mRNA and protein levels. Search Tool for the Retrieval of Interacting Genes-based molecular action analysis suggested a conserved interaction architecture across species and indicated potential functional linkages connecting hormone receptors and angiogenesis modules with Ras-related components and downstream cell cycle factors. Thus, porcine CL reveals coordinated, phase-dependent alterations in steroidogenic activity, angiogenesis, cell cycle regulation, apoptosis, and Ras-related signaling components during the estrous cycle. In conclusion, these findings provide foundational evidence that Ras signaling pathways act as integrative regulatory modules linking endocrine and vascular cues to intracellular signaling during the estrous cycle. This supports further porcine-specific mechanistic studies to clarify the Ras-centered regulation of CL function.