Browsing by Subject "amnion"
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Item Open Access Infection-induced thrombin production: a potential novel mechanism for preterm premature rupture of membranes (PPROM).(American journal of obstetrics and gynecology, 2018-07) Feng, Liping; Allen, Terrence K; Marinello, William P; Murtha, Amy PPreterm premature rupture of membranes is a leading contributor to maternal and neonatal morbidity and death. Epidemiologic and experimental studies have demonstrated that thrombin causes fetal membrane weakening and subsequently preterm premature rupture of membranes. Although blood is suspected to be the likely source of thrombin in fetal membranes and amniotic fluid of patients with preterm premature rupture of membranes, this has not been proved. Ureaplasma parvum is emerging as a pathogen involved in prematurity, which includes preterm premature rupture of membranes; however, until now, prothrombin production that has been induced directly by bacteria in fetal membranes has not been described.This study was designed to investigate whether Ureaplasma parvum exposure can induce prothrombin production in fetal membranes cells.Primary fetal membrane cells (amnion epithelial, chorion trophoblast, and decidua stromal) or full-thickness fetal membrane tissue explants from elective, term, uncomplicated cesarean deliveries were harvested. Cells or tissue explants were infected with live Ureaplasma parvum (1×105, 1×106 or 1×107 colony-forming units per milliliter) or lipopolysaccharide (Escherichia coli J5, L-5014; Sigma Chemical Company, St. Louis, MO; 100 ng/mL or 1000 ng/mL) for 24 hours. Tissue explants were fixed for immunohistochemistry staining of thrombin/prothrombin. Fetal membrane cells were fixed for confocal immunofluorescent staining of the biomarkers of fetal membrane cell types and thrombin/prothrombin. Protein and messenger RNA were harvested from the cells and tissue explants for Western blot or quantitative reverse transcription polymerase chain reaction to quantify thrombin/prothrombin protein or messenger RNA production, respectively. Data are presented as mean values ± standard errors of mean. Data were analyzed using 1-way analysis of variance with post hoc Dunnett's test.Prothrombin production and localization were confirmed by Western blot and immunostainings in all primary fetal membrane cells and tissue explants. Immunofluorescence observations revealed a perinuclear localization of prothrombin in amnion epithelial cells. Localization of prothrombin in chorion and decidua cells was perinuclear and cytoplasmic. Prothrombin messenger RNA and protein expression in fetal membranes were increased significantly by Ureaplasma parvum, but not lipopolysaccharide, treatments in a dose-dependent manner. Specifically, Ureaplasma parvum at a dose of 1×107 colony-forming units/mL significantly increased both prothrombin messenger RNA (fold changes in amnion: 4.1±1.9; chorion: 5.7±4.2; decidua: 10.0±5.4; fetal membrane: 9.2±3.0) and protein expression (fold changes in amnion: 138.0±44.0; chorion: 139.6±15.1; decidua: 56.9±29.1; fetal membrane: 133.1±40.0) compared with untreated control subjects. Ureaplasma parvum at a dose of 1×106 colony-forming units/mL significantly up-regulated prothrombin protein expression in chorion cells (fold change: 54.9±5.3) and prothrombin messenger RNA expression in decidua cells (fold change: 4.4±1.9).Our results demonstrate that prothrombin can be produced directly by fetal membrane amnion, chorion, and decidua cells. Further, prothrombin production can be stimulated by Ureaplasma parvum exposure in fetal membranes. These findings represent a potential novel underlying mechanism of Ureaplasma parvum-induced rupture of fetal membranes.Item Open Access Maternal and Fetal Genetic Contributions to Preterm Birth(2022) Cunningham, Sarah JeanPreterm birth is a major public health issue, affecting approximately 10% of pregnancies in the United States. The causes of preterm birth include the genetics of the mother, the genetics of the fetus, the environment, and the interplay of any combination of these factors. Maternal genetics is a significant contributor to preterm birth but few genome wide association studies (GWAS) have identified associated genetic variants. Recently, the largest GWAS on preterm birth to date found several loci associated with preterm birth that suggest impaired decidualization of the endometrium may play a role. To investigate regulatory activity in genomic regions identified via GWAS, we used the massively parallel reporter assay STARR-seq. Motifs enriched in peaks of significant activity include many transcription factors known to have critical roles in decidualization of the endometrium. An additional factor leading to preterm birth is maternal psychological stress. Maternal psychological stress is particularly linked to PPROM, the leading identifiable cause of preterm birth. PPROM is a pregnancy complication in which the chorion and amnion weaken and rupture prior to 37 weeks of pregnancy and before contractions have begun. PPROM is responsible for 30-40% of preterm birth cases. PPROM is closely linked to maternal psychological stress, leading us to hypothesize that glucocorticoid signaling may contribute to PPROM. As a step towards testing that hypothesis, we investigated the gene expression effects of glucocorticoids in primary amnion cells using RNA-seq. KCNA5 emerged as a potential GR regulated gene. KCNA5 has previously been reported to be a cell stress sensor that regulates proliferation and apoptosis. KCNA5 knockdown significantly increased cell proliferation without appearing to impact apoptosis and CRISPR-mediated over expression of endogenous KCNA5 decreased in cell proliferation. Taken together, these results suggest that glucocorticoid-mediated activation of KCNA5 contributes to decreased cell proliferation in the amnion epithelium. Decreases in amnion epithelial proliferation could impair the ability of these cells to repair microfractures in the membrane and lead to overall membrane weakening. We were able to study endocrine responses in pregnancy relevant cells to understand more broadly how these interactions affect preterm birth. Greater understanding of the interaction between preterm birth risk factors will move our understanding of the field forward.