Lipopolysaccharide- and Lipoteichoic Acid-mediated Pro-inflammatory Cytokine Production and Modulation of TLR2, TLR4 and MyD88 Expression in Human Endometrial Cells.
BACKGROUND
Toll-like receptor (TLR)-mediated inflammatory processes are supposed to be involved in pathophysiology of spontaneous abortion and preterm labor. Here, we investigated functional responses of human endometrial stromal cells (ESCs) and whole endometrial cells (WECs) to lipopolysaccharide (LPS) and lipoteichoic acid (LTA).


METHODS
Endometrial tissues were obtained from 15 cycling women who underwent laparoscopic tubal ligation. Modulation of TLR2, TLR4 and MyD88 expression and production of pro-inflammatory cytokines by WECs and ESCs in response to LPS and LTA were assessed.


RESULTS
WECs and ESCs expressed significant levels of TLR4 and MyD88 transcripts but, unlike WECs, ESCs failed to express TLR2 gene. Regardless of positive results of Western blotting, ESCs did not express TLR4 at their surface as judged by flow cytometry. Immunofluorescent staining revealed intracellular localization of TLR4 with predominant perinuclear pattern. LPS stimulation marginally increased TLR4 gene expression in both cell types, whereas such treatment significantly upregulated MyD88 gene expression after 8 hr (p < 0.05). At the protein level, however, LPS activation significantly increased TLR4 expression by ESCs (p < 0.05). LTA stimulation of WECs was accompanied with non-significant increase of TLR2 and MyD88 transcripts. LPS and LTA stimulation of WECs caused significant production of IL-6 and IL-8 in a dose-dependent manner (p < 0.05). Similarly, ESCs produced significant amounts of IL-6, IL-8 and also TNF-α in response to LPS activation (p < 0.05).


CONCLUSIONS
Our results provided further evidence of initiation of inflammatory processes following endometrial TLR activation by bacterial components which could potentially be harmful to developing fetus.
Immunology Department, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Nesa
N
Rashidi
Immunology Department, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Mahroo
M
Mirahmadian
Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
Mahmood
M
Jeddi-Tehrani
Biophysics Institute, Medical University of Graz, Graz, Austria.
Simin
S
Rezania
Nanobiotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
Jamileh
J
Ghasemi
Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
Somaieh
S
Kazemnejad
Reproductive Immunology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
Ebrahim
E
Mirzadegan
Nanobiotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
Sedigheh
S
Vafaei
Department of Obstetrics and Gynecology, Shahid Akbar-Abadi Hospital, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
Maryam
M
Kashanian
Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
Zahra
Z
Rasoulzadeh
Reproductive Immunology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran ; Immunology Research Center, Iran University of Medical Sciences, Tehran, Iran.
Amir-Hassan
AH
Zarnani
Cytokine; Endometrium; Inflammation; LPS; LTA; Toll-like receptor