Transcriptomic Insights into Tumor Necrosis Factor α’s Role in the Fibrosis-Related Processes of Equine Endometrial Fibroblasts

Equine endometrosis is a chronic degenerative condition of the endometrium. A hallmark feature of endometrosis is endometrial fibrosis accompanied by degenerative changes in the adjacent tissue structure. Tumor necrosis factor α (TNFα), a pleiotropic cytokine produced by various immune cells, plays a dual role in coordinating immune responses and regulating cell/tissue homeostasis, making it an important regulator of fibrotic-related disorders. However, the exact role of TNFα in the development of equine endometrial fibrosis remains to be discovered and explained. Therefore, the main aim of the current study was to establish the effects of TNFα on the equine endometrial fibroblast transcriptome as well as on proliferation and expression of ECM-associated factors in <i>in vitro</i> cultured fibroblasts derived from non-fibrotic equine endometrium. RNA-sequencing revealed changes in the expression of 737 genes (p_adjusted < 0.05; log2FC ≥ 1.0/log2FC ≤ -1.0) between untreated and TNFα-treated equine endometrial fibroblasts. These genes are involved in, i.a., B cell activation, proliferation and differentiation, cell cycle, canonical NF-κB signal transduction, ERK1 and ERK2 cascade, and p53 signaling pathway. Moreover, it was found that TNFα increased fibroblast proliferation and affected the expression of metalloproteinases and their tissue inhibitors in mare endometrial fibroblasts. Results of the current study highlight that TNFα modulates the expression of genes related to immune cell activation, cell fate, and ECM remodeling in <i>in vitro</i> cultured equine endometrial fibroblasts, suggesting TNFα contribution in development of fibrosis in the mare endometrium. Since the current study provides mechanistic insight into TNFα action, these findings provide a foundation for future research aimed at targeting TNFα-mediated pathways as potential therapeutic strategies to mitigate equine endometrial fibrosis progression.