Chorioamnionitis (ChA) modifies CX3CL1 (fractalkine) production by human amniotic epithelial cells (HAEC) under normoxic and hypoxic conditions.
BACKGROUND
Chemokine CX3CL1 possesses unique properties, including combined adhesive and chemotactic functions. Human amniotic epithelial cells (HAEC) show expression of CX3CL1 receptor (CX3CR1) and produce CX3CL1 in response to both physiologic and pathologic stimuli. Chorioamnionitis (ChA) is a common complication of pregnancy and labour. ChA is often accompanied by local hypoxia because of the high oxygen consumption at the site of inflammation. We examined comparatively (ChA-complicated vs. normal pregnancy) CX3CR1 expression and the effects of hypoxia, lipopolysaccharide (LPS), and CX3CR1 blockade on CX3CL1 production in HAEC cultured in vitro.


METHODS
HAEC have been isolated using trypsinization, and cultured under normoxia (20% O2) vs. hypoxia (5% O2). According to the experimental design, LPS (1 μg/ml) and neutralizing anti-CX3CR1 antibodies were added at respective time points. Mean CX3CL1 concentration in the supernatant samples were determined by ELISA. Expression of immunostained CX3CR1 was analyzed using quantitative morphometry.


RESULTS
We have found that the mean levels of CX3CL1 and CX3CR1 expression were remarkably (p < 0.05) higher in ChA, compared to normal pregnancy. Significantly increased expression of CX3CR1 was observed in ChA during both normoxia and hypoxia. Hypoxia exposure produced decrease in the mean concentration of CX3CL1 in both groups, however this reduction was stronger in normal pregnancy. In normoxia, LPS-evoked rise in the mean concentration of CX3CL1 was higher (p < 0.05) in normal pregnancy. This response was positively correlated with CX3CR1 expression. Blockade of CX3CR1 canceled the secretory response to LPS in all groups.


CONCLUSIONS
ChA-complicated pregnancy up-regulates CX3CR1 in HAEC cultured in vitro with simultaneous increase in CX3CL1 production. Hypoxia-resistant production of CX3CL1 may be responsible for ChA-related complications of pregnancy and labor.
Department of General & Experimental Pathology, Medical University of Warsaw, ul.Krakowskie Przedmiescie 26/28, Warsaw 00-928, Poland.
Dariusz
D
Szukiewicz
Department of Neurology, Second Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland.
Jan
J
Kochanowski
Department of Obstetrics & Gynecology, Second Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland.
Tarun Kumar
TK
Mittal
Department of General & Experimental Pathology, Medical University of Warsaw, ul.Krakowskie Przedmiescie 26/28, Warsaw 00-928, Poland.
Michal
M
Pyzlak
Department of General & Experimental Pathology, Medical University of Warsaw, ul.Krakowskie Przedmiescie 26/28, Warsaw 00-928, Poland.
Grzegorz
G
Szewczyk
Department of Obstetrics & Gynecology, Second Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland.
Krzysztof
K
Cendrowski
CX3CL1; Chorioamnionitis; Fractalkine; Human amniotic epithelial cells; Hypoxia