Enhanced expression of intercellular adhesion molecule-1 (ICAM-1) in amnion with term and preterm labour

Immune regulation by activation markers at feto-maternal interface in infection-associated spontaneous preterm birth

BACKGROUND

Spontaneous preterm birth (sPTB) is a global health concern. Studies reveal infections are majorly responsible for sPTB and immune activation markers play a role in regulation of maternal immune responses against pathogens during sPTB.

AIM

To study the mRNA expression and correlation of activation markers (CD66a, ICAM1, ITGB1, TIM3, CD25, CD95) and associated cytokines (IL-1β and IL-17)/prostaglandin receptors (EP2 and IP) in the placenta of Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum-infected sPTB women.

METHODS

Placental samples were collected from 160 sPTB and 160 term birth women. PCR was used for the detection of C. trachomatis, M. hominis, U. urealyticum. The mRNA expression of activation markers, cytokines and prostaglandin receptors was evaluated by real-time qPCR.

RESULTS

The fold-change expression of CD66a, ICAM1, TIM3, CD25 and CD95 was 2.89, 5.5, 4.95, 6.44 and 6.95-fold (p < 0.001), respectively; while for cytokines- IL-1β and IL-17 was 5.41 and 4.71-fold (p < 0.001), respectively and for prostaglandin receptors- EP2 and IP was 5.5 and 5-fold (p < 0.001) upregulated, respectively in infected sPTB women. Significant positive correlation was obtained among ICAM-1 and IL-1β/EP2/IL-17, TIM3 and IP/IL-17. Significant negative correlation was obtained between CD66a and EP2/IL-17, CD25 and IL-1β/EP2, CD95 and IL-1β/EP2 in infected sPTB women.

CONCLUSIONS

CD66a, ICAM1 and TIM3 may play role in inflammation and have potential for the clinical beginning of preterm labour during infection while CD25 and CD95 are possibly involved in immunotolerance at feto-maternal interface during C. trachomatis, M. hominis and U. urealyticum infection.

The short-chain fatty acids butyrate and propionate protect against inflammation-induced activation of mediators involved in active labor: implications for preterm birth

Spontaneous preterm birth is a global health issue affecting up to 20% of pregnancies and leaves a legacy of neurodevelopmental complications. Inflammation has been implicated in a significant proportion of preterm births, where pro-inflammatory insults trigger production of additional pro-inflammatory and pro-labor mediators. Thus, novel therapeutics that can target inflammation may be a novel avenue for preventing preterm birth and improving adverse fetal outcomes. Short-chain fatty acids (SCFAs), such as butyrate and propionate, are dietary metabolites produced by bacterial fermentation of fiber in the gut. SCFAs are known to possess anti-inflammatory properties and have been found to function through G-coupled-receptors and histone deacetylases. Therefore, this study aimed to investigate the effect of SCFAs on pro-inflammatory and pro-labor mediators in an in vitro model of preterm birth. Primary human cells isolated from myometrium and fetal membranes (decidua, amnion mesenchymal and amnion epithelial cells) were stimulated with the pro-inflammatory cytokines tumor necrosis factor alpha (TNF) or interleukin 1B (IL1B). The SCFAs butyrate and propionate suppressed inflammation-induced expression of pro-inflammatory cytokines and chemokines, adhesion molecules, the uterotonic prostaglandin PGF2alpha and enzymes involved in remodeling of myometrium and degradation of the fetal membranes. Notably, propionate and butyrate also suppressed inflammation-induced prostaglandin signaling and myometrial cell contraction. These effects appear to be mediated through suppression of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) activation. These results suggest that the SCFAs may be able to prevent myometrial contractions and rupture of membranes. Further in vivo studies are warranted to identify the efficacy of SCFAs as a novel anti-inflammatory therapeutic to prevent inflammation-induced spontaneous preterm birth.

GIT2 deficiency attenuates inflammation-induced expression of pro-labor mediators in human amnion and myometrial cells†

Untimely activation of the inflammatory response by sterile or infective insults in uterine tissues can result in preterm birth. Pro-inflammatory cytokines and pathogenic activation of toll-like receptors (TLRs) initiate a biochemical cascade of events leading to myometrial activation and contractility, cervical dilatation, and rupture of the chorioamniotic membranes. GIT2 is a signaling protein known to play a role in innate and adaptive immunity; however, its role in the inflammatory pathways of human labor is not known. In this article, we report that GIT2 expression is lower in human myometrium and fetal membranes with term labor, and in preterm amnion with histological chorioamnionitis. GIT2 knockdown by siRNA in primary myometrial and amnion cells exhibited reduced expression of pro-inflammatory cytokines and chemokines in response to inflammatory challenge by cytokines or TLR ligands. In addition, the pro-inflammatory cytokines IL1B and TNF could not induce the expression of extracellular matrix degrading enzymes in GIT2-deficient amnion cells. Myometrial activation in response to pro-inflammatory cytokines was also significantly suppressed in GIT2-deficient cells as evidenced by decreased prostaglandin release and expression of contraction-associated proteins. Further to this, collagen gel assays demonstrated that TNF had a reduced ability to induce myometrial contractility in situ in GIT2-deficient myometrial cells compared to control-transfected cells. In summary, the loss of GIT2 diminishes the effects inflammatory mediators have in promoting myometrial contraction and fetal membrane rupture in vitro, suggesting that GIT2 could be a possible target for preterm birth therapies.

Expression and localization of cell adhesion molecules in human fetal membranes during parturition

There is increasing evidence to support the view that human parturition represents an inflammatory process. We have previously demonstrated that parturition is associated with leukocyte invasion and pro-inflammatory cytokine production in the cervix and myometrium. Furthermore, we have shown that several cell adhesion molecules are upregulated in these tissues during labor. In fetal membranes, previous studies have shown intercellular adhesion molecule-1 (ICAM-1) upregulation in association with labor. The role of other adhesion molecules has not been explored. The aims of this study were, therefore, to determine the expression of ICAM-1, platelet endothelial cell adhesion molecule (PECAM), vascular cell adhesion molecule (VCAM) and E-selectin in pre- and post-laboring amnion and choriodecidua and to identify cell types responsible for their expression. Biopsies of fetal membranes were obtained from pregnant women delivered by caesarean section before the onset of labor (n = 8) and following spontaneous vaginal delivery (n = 8). Cell adhesion molecules were identified using immunohistochemistry and messenger RNA expression quantified using Northern analysis. We found that following labor, ICAM-1 mRNA expression was significantly upregulated in amnion and choriodecidua (P < 0.05). PECAM mRNA expression was also increased in choriodecidua (P < 0.05). The main cell types responsible for adhesion molecule expression were leukocytes, amniotic epithelial cells and endothelial cells. The upregulation of ICAM-1 and PECAM mRNA expression in fetal membranes following labor provides further evidence that fetal membranes play an important role in the inflammatory process of parturition.

Expression of adhesion molecules in the lower uterine segment during term and preterm parturition

Term and preterm cervical ripening and dilatation have similarities with an inflammatory reaction. Since cell adhesion molecules are involved in this process, investigations on the expression of intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, vascular cell adhesion molecule-1, and platelet endothelial cell adhesion molecule in the lower uterine segment and in vitro experiments on human umbilical vein endothelial cells were performed. In addition, current reports on expression of endothelial adhesion molecules by the uterine cervix were summarized. Cell adhesion molecule expression by lower uterine segment and uterine cervix in term and preterm parturition was measured using immunohistochemistry, enzyme immunoassay, and Northern blot analysis. Regulation of adhesion molecule expression was evaluated in vitro by indirect immunofluorescence and flow cytometry using human umbilical vein endothelial cells. Investigations in term parturition revealed that intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1 expression increases during parturition. In preterm labor, the expression of endothelial leukocyte adhesion molecule-1 and intercellular adhesion molecule-1 in the lower uterine segment increased. Expression of platelet endothelial cell adhesion molecule did not change in term and preterm parturition. Expression of adhesion molecules was localized mainly on lower uterine segment vascular endothelial cells and to a smaller extent on leukocytes. In vitro experiments showed that expression of adhesion molecules by human umbilical vein endothelial cells can be stimulated by tumor necrosis factor-alpha, 17beta-estradiol, prostaglandin E(2), and the antigestagen onapristone. Progesterone exerted no stimulatory effect. Cervical ripening and dilatation during term and preterm parturition are associated with an increased expression of endothelial cell adhesion molecules by lower uterine segment and uterine cervix. The expression can be modulated by pro-inflammatory cytokines, sex hormones, and prostaglandin E(2). Mechanisms controlling the extravasation of leukocytes may play a fundamental role in term and preterm parturition.

The 15-deoxy-delta(12,14)-prostaglandin J(2)receptor, peroxisome proliferator activated receptor-gamma (PPARgamma) is expressed in human gestational tissues and is functionally active in JEG3 choriocarcinoma cells

RNA was extracted from human gestational membranes and villous placental tissue following spontaneous delivery (n = 15) or elective caesarean section (n = 15) at term. The samples were subjected to Northern analysis, using a 2 kb cDNA probe for peroxisome proliferator activated receptor (PPAR)-gamma. The mRNA was detectable in all choriodecidual and villous placental samples, irrespective of mode of delivery, but was only rarely detectable in the amnion. The JEG3 choriocarcinoma cell line also expressed PPARgamma. In order to evaluate PPAR mediated transcriptional activation in JEG3 cells, the cells were transfected with pTK-PPREx3-luc, a PPAR response element (PPRE) containing luciferase reporter construct. Subsequent treatment with 10 microm 15-deoxy-delta(12,14)prostaglandin J(2)(15dPGJ(2)) resulted in an eight-fold stimulation of luciferase production relative to controls transfected with the same construct lacking the PPRE. This stimulation was concentration-dependent. These results suggest roles for PPARgamma and its ligand in lipid, steroid and inflammatory mediator homeostasis and in remodelling of gestational tissues.

Enhanced expression of intercellular adhesion molecule-1 (ICAM-1) in amnion with term and preterm labour

To evaluate the association between intercellular adhesion molecule-1 (ICAM-1) in the amnion and preterm labour and delivery, we have assessed ICAM-1 mRNA abundance by Northern analysis and protein levels by enzyme-linked immunosorbent assay (ELISA), in samples of this tissue after term and preterm delivery. The median ICAM-1 mRNA expression following preterm delivery (PTD, n=30) was 24 times greater (P< 0.05) than following elective caesarean section prior to labour at term (CST, n=14). ICAM-1 expression following vaginal delivery after spontaneous labour at term (SLT, n=11) was seven times greater than in the CST group (P< 0.05). The concentration of ICAM-1 protein in the PTD samples (n=31) was four-fold greater than (P< 0.05) in CST (n=14). It was also three-fold greater than in the SLT (n=15) samples (P< 0.05). The results were substantially the same when a preterm spontaneous labour group (PTL) (n=26), exclusive of deliveries complicated by pre-eclampsia (n=1) or intrauterine growth restriction (n=3), was compared to the CST and SLT groups. The ICAM-1 mRNA expression did not differ significantly (P=0.93) between PTL with (n=12) or without (n=14) indicators of intrauterine infection. The results were similar when ICAM-1 protein concentrations were compared (P=0.43) between these two groups. These findings indicate that ICAM-1 is expressed by the human amnion and that this expression is elevated with preterm labour and delivery.