The in vitro effect of omentin-1 on the global proteome of granulosa cells from normal weight Large White and fat Meishan pigs.

Ovarian granulosa cells (Gc) play a vital role in follicle maturation and successful ovulation. Omentin-1 (ITLN1) is an adipokine involved in energy metabolism and insulin resistance; its expression has been demonstrated in the ovary and varies depending on the degree of pig fatness. However, its effect on the global proteome of Gc has not been previously investigated. It was hypothesized that ITLN1 affects the abundance of proteins involved in key processes occurring in Gc in pigs. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of Gc identified 208 significantly differentially abundant proteins (DAPs) in the Large White pigs, with 99 proteins upregulated and 109 downregulated. In fatter Meishan pigs, 42 statistically significant DAPs were identified, including 25 upregulated and 17 downregulated proteins. The identified DAPs were associated with the estrogen signaling pathway, cell cycle and DNA replication, protein synthesis, transport and maturation, cytoskeleton dynamics, cell signaling, and hormonal regulation. Notably, the number and identity of DAPs differed markedly between the two breeds, suggesting that ITLN1-mediated effects are modulated by fatness and breed-specific metabolic status. To further illustrate the observed differences, selected proteins were also analyzed using Western blotting and ELISA, which were consistent with the LC-MS/MS findings. The results indicate that ITLN1 has a modulatory influence on the porcine Gc proteome, which is dependent on fat content. This highlights the important role of ITLN1 in regulating ovarian functions. SIGNIFICANCE: This study provides a comprehensive proteomic analysis of porcine granulosa cells (Gc) after treatment with omentin-1 (ITLN1) in pigs with different fat content (Large White < Meishan). The identified differentially abundant proteins (DAPs) are intricately linked to critical biological pathways, including estrogen signaling, cell cycle regulation, DNA replication, protein synthesis and transport, cytoskeleton organization, and hormonal regulation. These findings enhance our understanding of the molecular mechanisms underpinning ovarian follicle development and breed-related reproductive traits in pigs. The insights gained could inform future strategies to improve fertility and reproductive efficiency in swine production, as well as provide a valuable resource for comparative studies on ovarian biology across species.