Expression of Toll-Like Receptors (TLR) and Responsiveness to TLR Agonists by Polarized Mouse Uterine Epithelial Cells in Culture1

Abstract

The objective of the present study was to examine the expression of Toll-like receptors (TLRs) by mouse uterine epithelial cells and to determine if stimulation of the expressed TLR induces changes in cytokine and/or chemokine secretion. Using RT-PCR, the expression of TLRs 1-6 by mouse uterine epithelial cells was demonstrated, with TLRs 7-9 expressed only periodically. In the absence of pathogen-associated molecular patterns, polarized uterine epithelial cells constitutively secrete interleukin (IL) 1A, cysteine-cysteine ligand (CCL) 2, IL6, granulocyte-macrophage colony-stimulating factor 2 (CSF2), tumor necrosis factor A (TNFA), CSF3, and IL8 in vitro, with levels of cytokines/chemokines secreted into the apical compartment being significantly greater than those released into the basolateral compartment. When added to the apical surface for 48 h before analysis, the TLR2-agonist Pam3Cys-Ser-(Lys)4 and TLR1/6-agonist peptidoglycan increased epithelial cell apical secretion of IL1A, CCL2, and IL6 and apical/basolateral bidirectional secretion of CSF2, TNFA, CSF3, and IL8 when compared to controls. The TLR3-agonist poly (I:C) significantly increased bidirectional secretion of CCL2, IL6, TNFA, and CSF2 and basolateral secretion of CSF3. Lastly, the TLR4-agonist lipopolysaccharide increased bidirectional secretion CCL2, CSF2, TNFA, CSF3, and IL8 and apical secretion of IL6. These results indicate that mRNAs for Tlr1 through Tlr6 are expressed by uterine epithelial cells and that treatment with specific TLR agonists alters the expression of key chemokines and proinflammatory cytokines that contribute to the defense of the uterus against potential pathogens.

Trichomonas vaginalisLipophosphoglycan Triggers a Selective Upregulation of Cytokines by Human Female Reproductive Tract Epithelial Cells

“…On the other hand, large intracellular stores of IL-1 and some small amounts of TNF-␣ are present in these cells and released upon membrane rupture and cell death (13). TNF-␣ and IL-1␤ induce NF-B activation via TNF receptor I and IL-1 receptor I, respectively, and also may act as Toll-like receptor agonists in the reproductive tract epithelial cells (28,42). The notion of the primary role of IL-1␤ and TNF-␣ in the T. vaginalis-induced inflammatory response has found indirect support in the evidence of increased cervicovaginal levels of these cytokines under pathological conditions commonly associated with trichomoniasis, e.g., vaginitis, bacterial vaginosis, HIV-1 infection, and preterm labor (6,30).…”

Peri‐Conceptual Cytokines – Setting the Trajectory for Embryo Implantation, Pregnancy and Beyond

“…25 Like several uterine epithelial cytokines, secretion occurs in a polarized manner, with preferential apical secretion into the luminal cavity. 46 In mice and possibly in women, TGFB and other factors in seminal plasma induce a further surge in synthesis in the pre-implantation period. [47][48][49] Other embryotrophic cytokines follow the same pattern of synthesis, including LIF, IL6 and several chemokines.…”

The involvement of the Toll-like receptor family in ovulation

“…Thus, we propose that there is a regulatory loop between sperm and COCs during the fertilization process. TLRs have also been reported in uterine [34] and oviductal tissue and to impact pre-term labor [35]. TLR2/4 may also respond to factors in addition to sperm that enter the reproductive tract, including bacteria, at times of infection [35].…”