title: Differential expression of toll-like receptors in the human placenta across early gestation.
abstract: Toll-like receptors (TLRs) are an essential component of the innate immune system. While a number of studies have described TLR expression in the female reproductive tract, few have examined the temporal expression of TLRs within the human placenta. We hypothesized that the pattern of TLR expression in the placenta changes throughout the first and second trimester, coincident with physiological changes in placental function and the demands of innate immunity. We collected first and second trimester placental tissue and conducted quantitative PCR analysis for TLRs 1-10, followed by immunohistochemistry to define the cell specific expression pattern of a subset of these receptors. Except for the very earliest time points, RNA expression for TLRs 1-10 was stable out to 20 weeks gestation. However, the pattern of protein expression evolved over time. Early first trimester placenta demonstrated a strong, uniform pattern predominantly in the inner villous cytotrophoblast layer. As the placenta matured through the second trimester, both the villous cytotrophoblasts and the pattern of TLR expression within them became disorganized and patchy, with putative Hofbauer cells now identifiable in the tissue also staining positive. We conclude from this data that placental TLR expression changes over the course of gestation, with a tight barrier of TLRs forming a wall of defense along the cytotrophoblast layer in the early first trimester that breaks down as pregnancy progresses. These data are relevant to understanding placental immunity against pathogen exposure throughout pregnancy and may aid in our understanding of the vulnerable period for fetal exposure to pathogens.
authors.affiliation: Division of Reproductive Immunology, Department of Obstetrics and Gynecology, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Pudney
authors.affiliation: Section of Infectious Disease, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA.
authors.forename: Xianbao
authors.initials: X
authors.lastname: He
authors.affiliation: Division of Reproductive Immunology, Department of Obstetrics and Gynecology, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA.
authors.forename: Zahrah
authors.initials: Z
authors.lastname: Masheeb
authors.affiliation: Department of Pathology and Laboratory Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Kindelberger
authors.affiliation: Division of Reproductive Immunology, Department of Obstetrics and Gynecology, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA. Electronic address: wkuohung@bu.edu.
authors.forename: Wendy
authors.initials: W
authors.lastname: Kuohung
authors.affiliation: Section of Infectious Disease, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA, USA. Electronic address: ringalls@bu.edu.
authors.forename: Robin R
authors.initials: RR
authors.lastname: Ingalls
mesh_terms: D002824:Chorionic Villi / Q000033:anatomy & histology / Q000378:metabolism*; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000378:metabolism*; D011262:Pregnancy Trimester, Second / Q000378:metabolism*; D051193:Toll-Like Receptors / Q000378:metabolism*
chemical_list: D051193:Toll-Like Receptors
keywords: Innate immunity; Placenta; Pregnancy; Reproductive immunology; Toll-like receptors