Toll‐like receptor 2 mediates the immune response of the bovine oviductal ampulla to sperm binding

Abstract

We previously reported that sperm binding to cultured bovine oviduct epithelial cells induces an anti-inflammatory immune response. Now we have developed a differentiated explant model to focus on the oviductal ampulla, where fertilization occurs, and to study the effect of sperm capacitation on the immune response. We used heparin to stimulate bovine sperm capacitation. Fluorescence imaging showed that 5,5ʹ,6,6ʹ-tetrachloro-1,1ʹ,3,3ʹ-tetraethylbenzimidazolyl-carbocyanine iodidelabeled sperm pretreated with (Hep (+)) or without (Hep (−)) heparin rapidly attached to the explant ciliated epithelium in similar numbers. However, only Hep (+) sperm upregulated explant messenger RNA (mRNA) transcription of TLR2, IL8, TGFB1, and PGES, without changes in TNFA and IL-10 expression, while Hep (−) sperm only upregulated PGES. The responses were primarily anti-inflammatory, with a greater response produced by Hep (+) sperm, which also produced a substantial increase in TLR2 protein expression in the epithelium. The addition of TLR1/2 (toll-like receptor 1/2) antagonist to the Hep (+) and (Hep (−)) sperm-explant coincubations reduced sperm attachment to the epithelium and inhibited TLR2 protein expression and some of the Hep (+) sperm-induced mRNA transcription. Our observations suggest that the ampullar epithelium immunologically reacts more strongly to sperm that have undergone heparin stimulation of capacitation. This anti-inflammatory

Changes in Oviductal Cells and Small Extracellular Vesicles miRNAs in Pregnant Cows

“…Increased expression level of TGFB1, as found in our pregnant group, is also present in bovine OECs cultured with embryos in vitro (81). However, it cannot be disregarded that the increase in TGFB1 levels is also related to sperm binding and induction of sperm-tolerance (80,82). Synergistically with TGFB1, the PTGES2, up-regulated in our pregnant group, participates in the eicosanoid metabolic process that will drive the production of PGE2 (83), promoting immune tolerance in the bovine oviduct (81,84).…”

Effects of Human Endothelial Progenitor Cell and Its Conditioned Medium on Oocyte Development and Subsequent Embryo Development

“…In line with their results, it can be indicated that a significantly high level of bFGF in EPC-CM activates the mRNA transcript levels of FGFR2/PTGS2 in cumulus cells and FGFR2/BMP15 in oocytes during IVM ( Figures 3, 6 and 7), which might modulate the cumulus expansion as well as high embryo developmental competence. IL-10 is an anti-inflammatory cytokine that plays an important role in regulating immune responses [67]. Bone marrow-derived macrophages co-cultured with EPC secreted a higher level of IL-10 than BMDM cultured alone in an in vitro system [68].…”

Toll-like Receptor 2 is Involved in Calcium Influx and Acrosome Reaction to Facilitate Sperm Penetration to Oocytes During in vitro Fertilization in Cattle

“…Initially, preliminary dose-dependent and time-dependent experiments were conducted to identify cytotoxic or detrimental effects of TLR2 antagonist and agonist on sperm motility and viability as analyzed by CASA and flow cytometry ( Supplementary Table S1 and Supplementary Figure S1 ). Next, based on our previous investigations ( Ezz et al, 2019 ; Akthar et al, 2019 ; Morillo, et al, 2020 ; Elesh et al, 2021 ) and our initial trials, the pre-treatment of sperm by TLR2 antagonist (100 µM) or agonist (100 ng ml −1 ) for 30 min was designated as an effective model to test our hypothesis without generating any cytotoxic or detrimental effects on sperm motility and viability.…”