TICAM1-Mediated TLR3/TLR4 Signaling Promotes Endometrial Stromal Cell Proliferation, Migration, and Invasion in Endometriosis via IRF3/IFN-β Axis

Endometriosis (EMs) is an estrogen-dependent inflammatory disease characterized by the presence of endometrial-like tissue outside the uterine cavity, yet its precise pathogenesis remains incompletely elucidated. TICAM1, a key adaptor protein in the Toll-like receptor (TLR) signaling pathway, is known to be involved in inflammatory responses; however, its specific role in EMs has not been defined. This study integrated evidence from clinical tissue samples of patients with ovarian endometriomas, in vitro studies, and in vivo models to explore the role of TICAM1 in EMs. TICAM1 expression was significantly upregulated in both eutopic and ectopic endometrium, with the highest levels observed in ectopic lesions, where it was primarily localized to stromal and glandular epithelial cells. Functional experiments showed that TICAM1 overexpression promoted the proliferation, migration, and invasion of human endometrial stromal cells (hESCs), while TICAM1 knockdown suppressed these activities. Concurrently, TLR3 and TLR4 were also upregulated in EMs tissues, and their activation increased TICAM1 expression. Knockdown of TICAM1 attenuated the enhanced cellular activities induced by TLR3/TLR4 activation. Mechanistically, IRF3 and IFN-β levels were elevated in both EMs tissues and TICAM1-overexpressing hESCs, while TICAM1 knockdown inhibited TLR3/TLR4-induced IRF3 phosphorylation and subsequent IFN-β production. These findings were further corroborated in a mouse model of EMs. Together, our findings suggest that TICAM1 may enhance the proliferation, migration, and invasion of hESCs by mediating TLR3/TLR4 signaling and promoting IRF3 phosphorylation and subsequent IFN-β production, thereby potentially contributing to EMs progression. Therefore, targeting TICAM1 may represent a potential therapeutic direction for ovarian endometrioma-associated EMs, while its relevance to superficial peritoneal and deep infiltrating EMs requires further investigation.