title: Functional Toll-like receptors in primary first-trimester trophoblasts.
abstract: Toll-like receptors (TLRs) are an important part of the body's danger response system and crucial for initiating inflammation in response to cellular stress, tissue damage, and infections. Proper placental development is sensitive to inflammatory activation, and a role for TLRs in trophoblast immune activation has been suggested, but no overall examination has been performed in primary trophoblasts of early pregnancy. This study aimed to broadly examine cell surface and endosomal TLR gene expression and activation in first-trimester trophoblasts. Gene expression of all ten TLRs was examined by quantitative RT-PCR (RT-qPCR) in primary first-trimester trophoblasts (n = 6) and the trophoblast cell line BeWo, and cytokine responses to TLR ligands were detected by quantitative multiplex immunoassay. Primary first-trimester trophoblasts broadly expressed all ten TLR mRNAs; TLR1, TLR2, TLR3, TLR4, and TLR6 mRNA were expressed by all primary trophoblast populations, while TLR5, TLR7, TLR8, TLR9, and TLR10 mRNA expression was more restricted. Functional response to ligand activation of cell surface TLR2/1, TLR4, and TLR5 increased IL-6 and/or IL-8 release (P < 0.01) from primary trophoblasts. For endosomal TLRs, TLR3 and TLR9 ligand exposure increased receptor-specific production of IL-8 (P < 0.01) and IFN-γ-induced protein 10 (IP-10; P < 0.001) or vascular endothelial growth factor A (VEGFA; P < 0.01). In contrast, BeWo cells expressed lower TLR mRNA levels and did not respond to TLR activation. In conclusion, primary first-trimester trophoblasts broadly express functional TLRs, with inter-individual variation, suggesting that trophoblast TLR2, TLR3, TLR4, TLR5, and TLR9 might play a role in early placental inflammation.
authors.affiliation: Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Liaison Committee between the Central Norway Regional Health Authority and Norwegian University of Science and Technology, Norway.
authors.forename: Line H
authors.initials: LH
authors.lastname: Tangerås
authors.affiliation: Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Liaison Committee between the Central Norway Regional Health Authority and Norwegian University of Science and Technology, Norway.
authors.forename: Guro S
authors.initials: GS
authors.lastname: Stødle
authors.affiliation: Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Guro D
authors.initials: GD
authors.lastname: Olsen
authors.affiliation: Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Ann-Helen
authors.initials: AH
authors.lastname: Leknes
authors.affiliation: Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Astrid S
authors.initials: AS
authors.lastname: Gundersen
authors.affiliation: Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Bente
authors.initials: B
authors.lastname: Skei
authors.affiliation: Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Anne Jorunn
authors.initials: AJ
authors.lastname: Vikdal
authors.affiliation: Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Liv
authors.initials: L
authors.lastname: Ryan
authors.affiliation: Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Bjørg
authors.initials: B
authors.lastname: Steinkjer
authors.affiliation: Department of Gynecology and Obstetrics, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.
authors.forename: Merete F
authors.initials: MF
authors.lastname: Myklebost
authors.affiliation: Department of Mathematical Sciences, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Mette
authors.initials: M
authors.lastname: Langaas
authors.affiliation: Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Rigmor
authors.initials: R
authors.lastname: Austgulen
authors.affiliation: Centre of Molecular Inflammation Research, and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway. Electronic address: ann-charlotte.iversen@ntnu.no.
authors.forename: Ann-Charlotte
authors.initials: AC
authors.lastname: Iversen
mesh_terms: D002460:Cell Line; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007249:Inflammation / Q000276:immunology*; D007371:Interferon-gamma / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051193:Toll-Like Receptors / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology*; D014327:Trophoblasts / Q000276:immunology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: C508606:CXCL8 protein, human; C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8; D012333:RNA, Messenger; D051193:Toll-Like Receptors; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D007371:Interferon-gamma
keywords: First trimester; Inflammation; Pregnancy; Toll-like receptors; Trophoblasts