[show abstract][hide abstract] ABSTRACT: CD300a is an immunomodulatory molecule of the immunoglobulin receptor superfamily expressed in the leukocytes of myeloid and lymphoid lineages. However, its biological function on CD8+ T lymphocytes remains largely unknown. This study was conducted to assess the biological significance of CD300a expression in T lymphocytes and to determine whether its expression in peripheral T lymphocytes changes in pregnant women presenting with antifetal rejection.
Microarray analysis was performed using total RNA isolated from peripheral CD300a+ and CD300a- T lymphocytes. Flow cytometric analysis of the peripheral blood samples of pregnant women and pathologic examination of the placentas were conducted.
A large number of genes (N = 1245) were differentially expressed between CD300a- and CD300a+ subsets of CD8+ T lymphocytes, which included CCR7, CD244, CX3CR1, GLNY, GZMB, GZMK, IL15, ITGB1, KLRG1, PRF1, and SLAMF7. Gene ontology analysis of differentially expressed genes demonstrated enrichment of biological processes such as immune response, cell death, and signal transduction. CD300a expression in CD8+ T lymphocytes was coupled to a more cytotoxic molecular signature. Of note, the proportion of CD300a+CD8+ T lymphocytes increased in pregnant women with chronic chorioamnionitis (antifetal rejection of the chorioamniotic membranes; P < 0.05).
The findings of this study strongly suggest an increase in systemic T-lymphocyte-mediated cytotoxicity in pregnant women with chronic chorioamnionitis as a manifestation of maternal antifetal rejection.
American Journal Of Reproductive Immunology 11/2011; 67(3):184-97. · 3.32 Impact Factor
[show abstract][hide abstract] ABSTRACT: Maternal tolerance of the fetus is essential for viviparity, yet anti-fetal rejection occurs in several pregnancy complications. Chronic chorioamnionitis is a feature of anti-fetal cellular rejection. There is a robust association between chronic chorioamnionitis and maternal seropositivity for anti-human leukocyte antigen (HLA) panel-reactive antibodies (PRA) at the time of delivery. This longitudinal study was performed to assess maternal HLA PRA status in early gestation and the temporal evolution of maternal HLA PRA in the context of chronic chorioamnionitis and, thereby, to determine whether HLA PRA during the course of pregnancy is useful for the detection of anti-fetal rejection.
Maternal sera obtained before 16 weeks of gestation and at delivery were analyzed for HLA PRA in cases with (N = 100) and without (N = 150) chronic chorioamnionitis.
IgG (but not IgM) HLA class I and II PRA positivity at delivery was higher in cases with chronic chorioamnionitis than in those without chronic chorioamnionitis. IgG HLA class I PRA positivity before 16 weeks of gestation was higher in cases with chronic chorioamnionitis than in those without (30.3 versus 13.3%; P = 0.001). Positive conversion (negative HLA PRA before 16 weeks of gestation but positive at delivery) of IgG HLA class I and II PRA was significantly associated with chronic chorioamnionitis. Fetal HLA class I antigen-specific antibodies were confirmed in 12 of 16 mothers tested who were sensitized to HLA class I antigens before 16 weeks of gestation.
Positive maternal HLA PRA before 16 weeks of gestation and the temporal evolution of maternal HLA PRA are associated with the presence of chronic chorioamnionitis at the time of delivery. Maternal IgG HLA PRA has the potential to be a monitoring tool of anti-fetal rejection. Furthermore, the findings herein indicate that subsets of fetuses are exposed to alloimmune HLA antibodies for months, especially in cases with chronic chorioamnionitis.
American Journal Of Reproductive Immunology 09/2011; 66(6):510-26. · 3.32 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study was performed to assess the biological significance of miR-210 in preeclampsia and small-for-gestational-age (SGA) pregnancies. Placental miR-210 expression was evaluated by quantitative RT-PCR (RT-qPCR) in the following groups: i) appropriate-for-gestational-age pregnancies (n = 72), ii) preeclampsia (n = 52), iii) SGA (n = 66), and iv)preeclampsia with SGA (n = 31). The effects of hypoxia (1% O(2)) on miR-210 and iron-sulfur cluster scaffold homologue (ISCU) expressions and miR-210 binding to ISCU 3' UTR were examined in Swan 71 and BeWo cell lines. Perls' reaction (n = 229) and electron microscopy (n = 3) were conducted to verify siderosis of trophoblasts. miR-210 expression was increased in preeclampsia and SGA cases and was decreased with birth weight and gestational age. In both cell lines, miR-210 was induced by hypoxia, whereas ISCU expression was decreased. The luciferase assay confirmed miR-210 binding to ISCU mRNA 3' UTR. RNA interference knockdown of ISCU expression in Swan 71, but not in BeWo, cells resulted in autophagosomal and siderosomal iron accumulation and a fourfold decrease of Matrigel invasion (P = 0.004). Placental ISCU expression was decreased in preeclampsia (P = 0.002) and SGA (P = 0.002) cases. Furthermore, hemosiderin-laden trophoblasts were more frequent in the placental bed of preterm preeclampsia and/or SGA births than in control cases (48.7% versus 17.9%; P = 0.004). Siderosis of interstitial trophoblasts is a novel pathological feature of preeclampsia and SGA. The findings herein suggest that ISCU down-regulation by miR-210 perturbing trophoblast iron metabolism is associated with defective placentation.
American Journal Of Pathology 08/2011; 179(2):590-602. · 4.52 Impact Factor
[show abstract][hide abstract] ABSTRACT: Chronic chorioamnionitis is found in more than one-third of spontaneous preterm births. Chronic chorioamnionitis and villitis of unknown etiology represent maternal anti-fetal cellular rejection. Antibody-mediated rejection is another type of transplantation rejection. We investigated whether there was evidence for antibody-mediated rejection against the fetus in spontaneous preterm birth.
This cross-sectional study included women with (1) normal pregnancy and term delivery (n = 140) and (2) spontaneous preterm delivery (n = 140). We analyzed maternal and fetal sera for panel-reactive anti-HLA class I and class II antibodies, and determined C4d deposition on umbilical vein endothelium by immunohistochemistry. Maternal anti-HLA class I seropositivity in spontaneous preterm births was higher than in normal term births (48.6% vs. 32.1%, p = 0.005). Chronic chorioamnionitis was associated with a higher maternal anti-HLA class I seropositivity (p<0.01), significant in preterm and term birth. Villitis of unknown etiology was associated with increased maternal and fetal anti-HLA class I and II seropositivity (p<0.05, for each). Fetal anti-HLA seropositivity was closely related to maternal anti-HLA seropositivity in both groups (p<0.01, for each). C4d deposition on umbilical vein endothelium was more frequent in preterm labor than term labor (77.1% vs. 11.4%, p<0.001). Logistic regression analysis revealed that chronic chorioamnionitis (OR = 6.10, 95% CI 1.29-28.83), maternal anti-HLA class I seropositivity (OR = 5.90, 95% CI 1.60-21.83), and C4d deposition on umbilical vein endothelium (OR = 36.19, 95% CI 11.42-114.66) were associated with preterm labor and delivery.
A major subset of spontaneous preterm births has a signature of maternal anti-fetal cellular and antibody-mediated rejections with links to fetal graft-versus-host disease and alloimmune reactions.
PLoS ONE 01/2011; 6(2):e16806. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: The mechanism of mouse parturition is thought to involve myometrial infiltration by amniotic fluid (AF) macrophages, activated by surfactant protein-A (SP-A). In humans, the concentration of AF SP-A decreases during labor, and no fetal macrophages are found in the myometrium after labor. Therefore, it appears that the mechanisms of labor in mice and humans are different. We investigated a potential role for SP-A in human pregnancy and parturition by examining SP-A expression patterns in AF and amnion. High molecular mass (>250 kDa) oligomeric SP-A was increased in AF with advancing gestation. Interestingly, these oligomers were more abundant in placental amnion before labor at term, while they increased primarily in reflected amnion during labor (p < 0.05). Immunoblotting showed a binding of high molecular mass SP-A in AF to amnion. In C57BL/6 mice, oligomeric SP-A was also readily detected in AF from E15 onwards, but not in amnion. Macrophage density in mice myometrium did not change with advancing gestational age. Microarray analysis of human amnion explants incubated with SP-A revealed a molecular signature of inhibited cytokine-cytokine receptor interaction with downregulation of IL-1beta, CXCL2, and CXCL5 mRNA expression. The findings in this study strongly suggest that SP-A signals amniotic anti-inflammatory response via AF during pregnancy. We propose that an SP-A interaction among AF, placental amnion, and reflected amnion is a unique mechanism for immunoregulation in human pregnancy akin to that established in lung biology. However, AF SP-A and fetal macrophages by themselves do not seem to be exclusive effectors of parturition in humans.
The Journal of Immunology 06/2010; 184(11):6479-91. · 5.52 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to compare the transcriptome between the site of membrane rupture and the chorioamniotic membranes away from the site of rupture.
The transcriptome of amnion and chorion (n=20 each) from and distal to the site of rupture from women with spontaneous labor and vaginal delivery at term after spontaneous rupture of membranes was profiled with Illumina HumanHT-12 microarrays. Selected genes were validated with the use of quantitative reverse transcription-polymerase chain reaction.
Six hundred seventy-seven genes were differentially expressed in the chorion between the rupture and nonrupture sites (false discovery rate<0.1; fold change>1.5). Quantitative reverse transcription-polymerase chain reaction confirmed the differential expression in 10 of 14 genes. Enriched biological processes included anatomic structure development, cell adhesion and signal transduction. Extracellular matrix-receptor interaction was the most impacted signaling pathway.
The transcriptome of fetal membranes after spontaneous rupture of membranes in term labor is characterized by region- and tissue-specific differential expression of genes that are involved in signature pathways, which include extracellular matrix-receptor interactions.
American journal of obstetrics and gynecology 05/2010; 202(5):462.e1-41. · 3.28 Impact Factor
[show abstract][hide abstract] ABSTRACT: Acute chorioamnionitis is a well-established lesion of the placenta in cases with intra-amniotic infection. In contrast, the clinicopathological significance of chronic chorioamnionitis is unclear. This study was conducted to determine the frequency and severity of chronic chorioamnionitis in normal pregnancy and in various pregnancy complications. Placentas from the following patient groups were studied: (1) term not in labor (n=100), (2) term in labor (n=100), (3) preterm labor (n=100), (4) preterm prelabor rupture of membranes (n=100), (5) preeclampsia at term (n=100), (6) preterm preeclampsia (n=100), and (7) small-for-gestational-age at term (n=100). Amniotic fluid CXCL10 concentration was measured in 64 patients. CXCL9, CXCL10, and CXCL11 mRNA expressions in the chorioamniotic membranes were assessed using real-time quantitative reverse transcription-PCR. The frequency of chronic chorioamnionitis in the preterm labor group and the preterm prelabor rupture of membranes group was 34 and 39%, respectively, which was higher than that of normal-term placentas (term not in labor, 19%; term in labor, 8%; P<0.05 each). The frequency of chronic chorioamnionitis in the preeclampsia at term group, preterm preeclampsia group, and small-for-gestational-age group was 23, 16, and 13%, respectively. Concomitant villitis of unknown etiology was found in 38 and 36% of preterm labor cases and preterm prelabor rupture of membranes cases with chronic chorioamnionitis, respectively. Interestingly, the median gestational age of preterm chronic chorioamnionitis cases was higher than that of acute chorioamnionitis cases (P<0.05). The median amniotic fluid CXCL10 concentration was higher in cases with chronic chorioamnionitis than in those without, in both the preterm labor group and preterm prelabor rupture of membranes group (P<0.05 and P<0.01, respectively). CXCL9, CXCL10, and CXCL11 mRNA expression in the chorioamniotic membranes was also higher in cases with chronic chorioamnionitis than in those without chronic chorioamnionitis (P<0.05). We propose that chronic chorioamnionitis defines a common placental pathological lesion among the preterm labor and preterm prelabor rupture of membranes groups, especially in cases of late preterm birth. Its association with villitis of unknown etiology and the chemokine profile in amniotic fluid suggests an immunological origin, akin to transplantation rejection and graft-versus-host disease in the chorioamniotic membranes.
Modern Pathology 03/2010; 23(7):1000-11. · 5.25 Impact Factor
[show abstract][hide abstract] ABSTRACT: The fetal inflammatory response syndrome (FIRS) is considered the counterpart of the systemic inflammatory response syndrome (SIRS), but similarities in their regulatory mechanisms are unclear. This study characterizes the fetal mRNA transcriptome of peripheral leukocytes to identify key biological processes and pathways involved in FIRS.
Umbilical cord blood from preterm neonates with FIRS (funisitis, plasma IL-6 >11 pg/mL; n = 10) and neonates with no evidence of inflammation (n = 10) was collected at birth. Results Microarray analysis of leukocyte RNA revealed differential expression of 541 unique genes, changes confirmed by qRT-PCR for 41 or 44 genes tested. Similar to SIRS and sepsis, ontological and pathway analyses yielded significant enrichment of biological processes including antigen processing and presentation, immune response, and processes critical to cellular metabolism.
are comparable with microarray studies of endotoxin challenge models and pediatric sepsis, identifying 25 genes across all studies.
This study is the first to profile genome-wide expression in FIRS, which demonstrates a substantial degree of similarity with SIRS despite differences in fetal and adult immune systems.
American Journal Of Reproductive Immunology 01/2010; 63(1):73-92. · 3.32 Impact Factor
[show abstract][hide abstract] ABSTRACT: The aim of this study was to identify changes in the cervical transcriptome in the human uterine cervix as a function of ripening before the onset of labor.
Human cervical tissue was obtained from women at term not in labor with ripe (n = 11) and unripe (n = 11) cervices and profiled using Affymetrix GeneChip HGU133Plus2.0 arrays. Gene expression was analyzed using a moderated t-test (False Discovery Rate 5%). Gene ontology and pathway analysis were performed. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used for confirmation of selected differentially expressed genes.
(1) Ninety-one genes were differentially expressed between ripe and unripe groups. (2) Cervical ripening was associated with enrichment of specific biological processes (e.g. cell adhesion, regulation of anatomical structure), pathways and 11 molecular functions (e.g. extracelluar matrix (ECM)-structural constituent, protein binding, glycosaminoglycan binding). (3) qRT-PCR confirmed that 9 of 11 tested differentially expressed genes (determined by microarray) were upregulated in a ripe cervix (e.g. MYOCD, VCAN, THBS1, COL5A1). (4) Twenty-three additional genes related to ECM metabolism and adhesion molecules were differentially regulated (by qRT-PCR) in ripe cervices.
(1) This is the first description of the changes in the human cervical transcriptome with ripening before the onset of labor. (2) Biological processes, pathways and molecular functions were identified with the use of this unbiased approach. (3) In contrast to cervical dilation after term labor, inflammation-related genes did not emerge as differentially regulated with cervical ripening. (4) Myocardin was identified as a novel gene upregulated in human cervical ripening.
The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 11/2009; 22(12):1183-93. · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Galectins are proteins that regulate immune responses through the recognition of cell-surface glycans. We present evidence that 16 human galectin genes are expressed at the maternal-fetal interface and demonstrate that a cluster of 5 galectin genes on human chromosome 19 emerged during primate evolution as a result of duplication and rearrangement of genes and pseudogenes via a birth and death process primarily mediated by transposable long interspersed nuclear elements (LINEs). Genes in the cluster are found only in anthropoids, a group of primate species that differ from their strepsirrhine counterparts by having relatively large brains and long gestations. Three of the human cluster genes (LGALS13, -14, and -16) were found to be placenta-specific. Homology modeling revealed conserved three-dimensional structures of galectins in the human cluster; however, analyses of 24 newly derived and 69 publicly available sequences in 10 anthropoid species indicate functional diversification by evidence of positive selection and amino acid replacements in carbohydrate-recognition domains. Moreover, we demonstrate altered sugar-binding capacities of 6 recombinant galectins in the cluster. We show that human placenta-specific galectins are predominantly expressed by the syncytiotrophoblast, a primary site of metabolic exchange where, early during pregnancy, the fetus comes in contact with immune cells circulating in maternal blood. Because ex vivo functional assays demonstrate that placenta-specific galectins induce the apoptosis of T lymphocytes, we propose that these galectins reduce the danger of maternal immune attacks on the fetal semiallograft, presumably conferring additional immune tolerance mechanisms and in turn sustaining hemochorial placentation during the long gestation of anthropoid primates.
Proceedings of the National Academy of Sciences 07/2009; 106(24):9731-6. · 9.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: Hemoglobin and its catabolic products have been associated with amniotic fluid (AF) discoloration and intra-amniotic infection/inflammation (IAI). However, the origin of AF hemoglobin (maternal or fetal) has not been determined. The aims of this study were to determine if fetal hemoglobin can be detected in AF obtained from normal pregnancies, and whether there is an association between AF fetal hemoglobin concentrations and gestational age, spontaneous labor (term and preterm), preterm prelabor rupture of membranes (PPROM) and IAI.
This cross-sectional study included pregnant women in the following groups: (1) mid-trimester (n = 60); (2) term not in labor (n = 21); (3) term in labor (n = 47); (4) spontaneous preterm labor with intact membranes (PTL) without IAI who delivered at term (n = 89); (5) PTL without IAI who delivered preterm (n = 74); (6) PTL with IAI (n = 78); (7) PPROM with (n = 48) and (8) without IAI (n = 48). AF fetal hemoglobin concentrations were determined by ELISA. Non-parametric statistics were used for analyses.
(1) Fetal hemoglobin was detected in 80.4% of all AF samples; (2) women at term not in labor had a higher median AF fetal hemoglobin concentration than those at mid-trimester (p = 0.008); (3) labor at term was not associated with a significant difference in the median AF fetal hemoglobin concentration; (4) the median AF fetal hemoglobin concentration was not significantly different among the three PTL groups or between the PPROM groups; (5) women with PTL and IAI had a lower AF fetal hemoglobin percentage of the total hemoglobin than those without IAI who delivered preterm (p = 0.03) or at term (p < 0.001); (6) The median AF fetal hemoglobin concentration was higher in pregnancies complicated with PTL or PPROM than in women at term (p < 0.001 for all comparison).
(1) The concentration of immunoreactive AF fetal hemoglobin increases with gestational age; (2) the median AF fetal hemoglobin concentration is higher in pregnancies complicated with PTL or PPROM than in term pregnancies; (3) among women with PTL or PPROM, the AF fetal hemoglobin concentrations were not associated with IAI; (4) however, women with PTL and IAI had a lower percentage of AF fetal hemoglobin of the total hemoglobin than those without IAI, suggesting different mechanisms of disease.
The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 06/2009; 22(5):388-97. · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Acute chorioamnionitis is a response to amniotic fluid (AF) infection. However, it remains unclear whether substantial bacterial propagation in the chorioamniotic membranes (CAMs) precedes microbial invasion of the amniotic cavity (MIAC), which is inconsistent with characteristic 'amniotropic neutrophil migration' in acute chorioamnionitis. This study was performed to determine whether CAMs have widespread bacterial infection during MIAC and whether bacteria normally colonize CAMs. AF pellets and CAMs from the following groups were studied: group 1, patients with positive (n=18) or negative (n=22) AF cultures; group 2, patients with or without acute chorioamnionitis in which the amnion and chorion were studied separately (n=60); and group 3, patients at term who underwent a cesarean delivery (n=30). SYTO 9/propidium iodide fluorescent staining and fluorescent in situ hybridization for 16S rRNA were performed. Real-time quantitative PCR for 16S rDNA and PCR for genital mycoplasmas were also conducted. Bacteria were more frequently detected in AF than in CAMs of patients with positive AF culture (100 vs. 33%; P<0.0001). Bacteria were detected more frequently in CAMs as the severity of chorioamnionitis increased (P<0.01). The median 16S rRNA gene copy number in the amnion was significantly greater than in the chorion (group 2; P<0.0001). Bacteria were not detected in CAMs or AF in women at term before labor (group 3). A fraction of patients with chorioamnionitis or MIAC did not have bacteria in CAMs. Collectively, the findings herein indicate that MIAC does not follow widespread infection of CAMs, but precedes it. We propose a model of MIAC: the initial stage is intra-amniotic bacterial invasion through a discrete region of the CAMs, followed by intra-amniotic proliferation, and bacterial invasion of CAMs primarily extends from the amniotic fluid. This study emphasizes the importance of assessing the intra-amniotic compartment for diagnosis and treatment of preterm birth.
[show abstract][hide abstract] ABSTRACT: Placental mesenchymal dysplasia (PMD) is an uncommon vascular anomaly of the placenta characterized by mesenchymal stem villous hyperplasia. Its main sonographic feature is a thickened placenta with hypoechoic areas, and an accurate sonographic diagnosis is challenging. The aim of this study was to report 2 cases of PMD and discuss the differential diagnosis of its sonographic features.
Cases of placental masses were studied by 2-dimensional (2D), 3-dimensional (3D), and color Doppler imaging.
In case 1, a thick placenta with multiple hypoechoic areas was noted at 13 weeks' gestation. At 19 weeks, the multicystic area, clearly demarcated from a normal-looking placenta, measured 6.5 x 8.5 cm and enlarged gradually. The patient gave birth to a 625-g female neonate after spontaneous labor at almost 26 weeks' gestation. In case 2, a first sonographic examination at 25 weeks' gestation revealed a thickened placenta with hypoechoic areas and a fetus with a single umbilical artery and a ventricular septal defect. At 27 weeks, the abnormal area of the placenta measured 14.5 x 7.5 cm. At 32 weeks' gestation, a caesarean delivery was performed because of a nonreassuring fetal heart tracing, and a 1415-g female neonate was delivered. Both cases were evaluated by 2D, 3D, and color Doppler imaging, and the pathologic features of both placentas were consistent with PMD.
Placental mesenchymal dysplasia should be considered in the differential diagnosis of every placental mass, especially in cases of multicystic placental lesion with lack of high-velocity signals inside the lesion, and a normal karyotype.
Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 04/2009; 28(3):359-68. · 1.40 Impact Factor
[show abstract][hide abstract] ABSTRACT: The co-presence of histoincompatible fetal and maternal cells is a characteristic of human placental inflammation. Villitis of unknown etiology (VUE), a destructive inflammatory lesion of villous placenta, is characterized by participation of Hofbauer cells (placental macrophages) and maternal T cells. In contrast to acute chorioamnionitis of infection-related origin, the fundamental immunopathology of VUE is unknown. This study was performed to investigate the placental transcriptome of VUE and to determine whether VUE is associated with systemic maternal and/or fetal inflammatory response(s). Comparison of the transcriptome between term placentas without and with VUE revealed differential expression of 206 genes associated with pathways related to immune response. The mRNA expression of a subset of chemokines and their receptors (CXCL9, CXCL10, CXCL11, CXCL13, CCL4, CCL5, CXCR3, CCR5) was higher in VUE placentas than in normal placentas (p < 0.05). Analysis of blood cell mRNA showed a higher expression of CXCL9 and CXCL13 in the mother, and CXCL11 and CXCL13 in the fetus of VUE cases (p < 0.05). The median concentrations of CXCL9, CXCL10, and CXCL11 in maternal and fetal plasma were higher in VUE (p < 0.05). Comparison of preterm cases without and with acute chorioamnionitis revealed elevated CXCL9, CXCL10, CXCL11, and CXCL13 concentrations in fetal plasma (p < 0.05), but not in maternal plasma with chorioamnionitis. We report for the first time the placental transcriptome of VUE. A systemic derangement of CXC chemokines in maternal and fetal circulation distinguishes VUE from acute chorioamnionitis. We propose that VUE be a unique state combining maternal allograft rejection and maternal antifetal graft-vs-host disease mechanisms.
The Journal of Immunology 03/2009; 182(6):3919-27. · 5.52 Impact Factor
[show abstract][hide abstract] ABSTRACT: Gene expression class comparison studies may identify hundreds or thousands of genes as differentially expressed (DE) between sample groups. Gaining biological insight from the result of such experiments can be approached, for instance, by identifying the signaling pathways impacted by the observed changes. Most of the existing pathway analysis methods focus on either the number of DE genes observed in a given pathway (enrichment analysis methods), or on the correlation between the pathway genes and the class of the samples (functional class scoring methods). Both approaches treat the pathways as simple sets of genes, disregarding the complex gene interactions that these pathways are built to describe.
We describe a novel signaling pathway impact analysis (SPIA) that combines the evidence obtained from the classical enrichment analysis with a novel type of evidence, which measures the actual perturbation on a given pathway under a given condition. A bootstrap procedure is used to assess the significance of the observed total pathway perturbation. Using simulations we show that the evidence derived from perturbations is independent of the pathway enrichment evidence. This allows us to calculate a global pathway significance P-value, which combines the enrichment and perturbation P-values. We illustrate the capabilities of the novel method on four real datasets. The results obtained on these data show that SPIA has better specificity and more sensitivity than several widely used pathway analysis methods.
SPIA was implemented as an R package available at http://vortex.cs.wayne.edu/ontoexpress/
[show abstract][hide abstract] ABSTRACT: The amnion plays an important role during pregnancy and parturition. Though referred to as a single structure, this fetal tissue is regionally divided into placental amnion, reflected amnion, and umbilical amnion. Histological differences between placental amnion and reflected amnion led us to hypothesize that the amnion is biologically heterogeneous. The gene expression profiles of placental amnion and reflected amnion were compared in patients at term with no labor (TNL; n = 10) and in labor (TIL; n = 10). Real-time quantitative RT-PCR revealed a higher expression of IL1B mRNA in reflected amnion than in placental amnion in TNL cases but not in TIL cases. Extended screening using microarrays showed differential expression of 17 genes in labor, regardless of the region. Interestingly, 839 genes were differentially expressed between placental amnion and reflected amnion. Pathway analysis identified 19 signaling pathways, such as mitogen-activated protein kinase and transforming growth factor beta pathways, associated with region. Lipopolysaccharide (LPS) treatment of the amnion explants showed more robust activation of mitogen-activated protein kinase 3/1 (extracellular signal-regulated kinase 1/2) in placental amnion of TNL but not in TIL cases. Placental amnion from TNL and TIL cases showed a significant difference in the amplitude of IL1B mRNA induction by LPS. We report that the anatomical region has a substantial impact on the transcriptional program and the biological properties of the amnion. Labor-associated switching to a proinflammatory signature is a feature particular to placental amnion. The novel observations herein strongly suggest that the seemingly homogeneous amnion is biologically heterogeneous and compartmentalized, with implications for the physiology of pregnancy and parturition.
Biology of Reproduction 09/2008; 79(5):954-61. · 4.03 Impact Factor
[show abstract][hide abstract] ABSTRACT: Mannose-binding lectin (MBL) is a pattern-recognition receptor that activates complement and modulates inflammation. Homozygosity for the most common allele of the MBL2 gene that is associated with high MBL serum concentrations is more prevalent among patients with pre-eclampsia. The objective of this study was to determine maternal plasma MBL concentrations in normal pregnant women and patients with pre-eclampsia.
This cross-sectional study included normal pregnant women (n = 187) and patients with pre-eclampsia (n = 99). Maternal plasma MBL concentrations were determined by ELISA.
Women with pre-eclampsia had a higher median maternal plasma MBL concentration than normal pregnant women. MBL concentration distribution curves were three-modal, the subintervals in normal pregnancy were low (< 143.7), intermediate (143.7-1898.9) and high (> 1898.9 ng/mL). The proportion of normal pregnant women was larger in the low subinterval, while the proportion of patients with preeclampsia was larger in the high subinterval (P = 0.02). Normal pregnant women in the high subinterval had a larger rate of placental underperfusion than those in the low and intermediate subintervals (P = 0.02).
The median maternal plasma MBL concentration is elevated in patients with pre-eclampsia and a larger proportion of these patients are in the high subinterval than normal pregnant women, suggesting that this component of the innate immune system is involved in the mechanisms of disease in pre-eclampsia.
American journal of reproductive immunology (New York, N.Y.: 1989) 09/2008; 60(4):333-45. · 3.32 Impact Factor
[show abstract][hide abstract] ABSTRACT: Preeclampsia (PE) is characterized by excessive thrombin generation, which has been implicated in the multiple organ damage associated with the disease. The biological effects of thrombin on coagulation and inflammation are mediated by protease-activated receptor-1 (PAR-1), a G protein-coupled receptor. The aim of this study was to determine whether preterm PE is associated with changes in placental expression of PAR-1.
This cross-sectional study included two groups matched for gestational age at delivery: (1) patients with preterm PE (<37 weeks of gestation; n = 26) and (2) a control group of patients with preterm labor without intra-amniotic infection (n = 26). Placental tissue microarrays were immunostained for PAR-1. Immunoreactivity of PAR-1 in the villous trophoblasts was graded as negative, weak-positive, or strong-positive.
(1) The proportion of cases with strong PAR-1 immunoreactivity was significantly higher in placentas of patients with PE than in placentas from the control group (37.5% (9/24) vs. 8.7% (2/23); p = 0.036, respectively). (2) PAR-1 immunoreactivity was found in the cellular compartments of the placental villous tree, mainly in villous trophoblasts and stromal endothelial cells. (3) PAR-1 was detected in 92.3% (24/26) of the placentas of women with PE and in 88.5% (23/26) of the placentas from the control group.
Placentas from pregnancies complicated by preterm PE had a significantly higher frequency of strong PAR-1 expression than placentas from women with spontaneous preterm labor. This observation is consistent with a role for PAR-1 as a mediator of the effect of thrombin on coagulation and inflammation in PE. We propose that the effects of thrombin in PE are due to increased thrombin generation and higher expression of PAR-1, the major receptor for this enzyme.
The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 06/2008; 21(6):345-55. · 1.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Human chorioamniotic membranes generate temporary but large mucosal surfaces. Due to lack of fetal vessels, macrophages represent the only subset of immunocytes of fetal origin available in the chorioamniotic mesodermal layer. This layer contains two distinct groups of cells: the fibroblasts/myofibroblasts and the macrophages; however, the relative contribution of these two cell populations has been a point of contention. In addressing various discrepancies, we hypothesized that cells in the chorioamniotic mesodermal layer have plasticity. Immunophenotyping of these cells using a panel of antibodies (CD14, CD68, CD163, HLA-DR, type I procollagen, alpha-smooth muscle actin, desmin, vimentin) revealed coexpression of both myofibroblast and macrophage markers. The proportion of CD14+ macrophages was higher in inflamed chorioamniotic membranes (P<0.05). Cells immunoreactive to the macrophage markers showed nuclear expression of PU.1, a hematopoietic cell-specific transcription factor. Furthermore, treatment with proinflammatory cytokines (IL-1beta and TNFalpha) or Toll-like receptor-4 overexpression upregulated PU.1 mRNA expression in chorioamniotic mesodermal cells. Overexpression of PU.1 in chorionic mesodermal cells increased the expression of CD14 mRNA and protein. A reporter gene assay and chromatin immunoprecipitation demonstrated binding of PU.1 to the CD14 promoter region. This study reports that chorioamniotic mesodermal cells display plasticity ranging from overt transformation of fibroblast/myofibroblast to macrophages, and that PU.1 plays a role in macrophage differentiation. Chorioamniotic mesodermal cells are another novel example of phenotypic switching between fibroblast/myofibroblast and macrophage. The findings reported herein suggest that the plasticity of mesodermal cells is an effective mechanism of the chorioamniotic membranes to manage several biological needs, such as mucosal immune defense and the maintenance/disruption of physical integrity, with a limited pool of cells.
[show abstract][hide abstract] ABSTRACT: There is a difference in the susceptibility to inflammation between the umbilical vein (UV) and the umbilical arteries (UAs). This led us to hypothesize that there is an intrinsic difference in the pro-inflammatory response between UA and UV. Real-time quantitative RT-PCR and microarray analysis revealed higher expression of interleukin (IL)-1beta and IL-8 mRNA in the UV and differential expression of 567 genes between the UA and UV associated with distinct biological processes, including the immune response. Differential expression of human leukocyte antigen (HLA)-DRA mRNA between the UA and UV was due to unexpected HLA-DR(+) cells migrating via the umbilical vessels into Wharton's jelly, more frequently in the UV. A significant proportion of these cells co-expressed CD45 and type I pro-collagen, and acquired CD163 or alpha-smooth muscle actin immunoreactivity in Wharton's jelly. Migrating cells were also found in the chorionic and stem villous vessels. Furthermore, the extent of migration increased with progression of gestation, but diminished in intrauterine growth restriction (IUGR). The observations herein strongly suggest that circulating foetal fibrocytes, routing via umbilical and placental vessels, are a reservoir for key cellular subsets in the placenta. This study reports fibrocytes in the human umbilical cord and placenta for the first time, and a novel role for both circulating foetal cells and the umbilical vessels in placental development, which is deranged in IUGR.
Journal of Cellular and Molecular Medicine 03/2008; 12(4):1317-30. · 4.75 Impact Factor