Browsing by Subject "Labor, Obstetric"
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Item Antagonistic Roles of miR-199a-3p/miR-214 and the miR-200 Family in the Regulation of Uterine Contractility During Pregnancy and Labor(2014-02-03) Williams, Koriand'r; Hammer, Robert; Mendelson, Carole R.; Mahendroo, Mala; Olson, Eric N.Progesterone (P4) and estradiol-17β (E2) play critical and opposing roles in regulating myometrial quiescence and contractility during pregnancy and labor (Kamel et al., 2010). While these contrasting hormonal effects are likely mediated via differential regulation of inflammatory and contractile genes, the underlying mechanisms remain incompletely understood. Recently, we discovered that miR-200 family members, miR-200b and miR-429, and their target, transcription factor ZEB1, serve as P4/progesterone receptor (PR)-mediated regulators of uterine quiescence during pregnancy (Renthal et al., 2010). In the present study, we identified a novel role for another miR-200 family member, miR-200a, to enhance local metabolism of P4 in myometrium and, thus, decrease PR function during the progression towards labor (Williams et. al., 2012a). This occurs via miR-200a repression of signal transducer and activator of transcription (STAT)5b, a transcriptional repressor of the P4-metabolizing enzyme 20α-hydroxysteroid dehydrogenase (20α-HSD). We observed that miR-200a expression increased and STAT5b expression coordinately decreased in myometrium of mice as they progressed to labor and in laboring myometrium from pregnant women. These changes were associated with a dramatic increase in expression and activity of 20α-HSD in laboring myometrium from mouse and human. In a progesterone-withdrawal mouse model of preterm labor, preterm labor was associated with increased miR-200a, decreased STAT5b and enhanced 20α-HSD expression. In other studies, we also found that levels of the clustered miRNAs, miR-199a-3p and miR-214, were significantly decreased in laboring myometrium of pregnant mice and humans and in a inflammatory mouse model of preterm labor, while the miR-199a-3p/miR-214 target, cyclooxygenase-2 (COX-2), a critical enzyme in synthesis of pro-inflammatory prostaglandins, was coordinately increased (Williams et al., 2012b). The physiological relevance of the labor-associated increase in miR-199a-3p/214 expression was highlighted by the finding that overexpression of miR-199a-3p and miR-214 in cultured human myometrial cells inhibited COX-2 protein and blocked TNF-α-induced myometrial cell contractility. Notably, estrogen and P4 treatment of ovariectomized mice have opposing effects on uterine miR-199a-3p/214 expression that were mediated by ZEB1. Whereas, P4 stimulated ZEB1 and upregulated miR-199a/214 expression in mouse and human myometrium (Renthal et al., 2010), estrogen had an opposing inhibitory effect. Notably, ZEB1/2 inhibit miR-200 family expression. Together, our findings point to the key pivotal roles of myometrial ZEB1 and its miRNA targets as a hormonally-controlled regulators of inflammatory and contractile gene expression in the pregnant uterus during term and preterm labor.Item Calcitriol Treatment Suppresses Contraction-Associated Gene Expression in Pregnant Mice Near Term(2018-01-23) Morgan, Kelsi; Yang, Ailling; Montalbano, Alina P.; Mendelson, Carole R.Preterm birth (PTB) is the leading cause of infant mortality during the first four weeks of life world-wide. This is due, in part, to our incomplete understanding of the mechanisms that mediate uterine quiescence during most of pregnancy and promote the transition to labor at term. Term and preterm labor are associated with increased levels of proinflammatory cytokines within maternal reproductive tissues where they activate inflammatory transcription factors (e.g. NF-κB) that enhance expression of genes encoding contraction-associated proteins (CAP) (i.e. connexin-43 (CX-43)), oxytocin receptor (OXTR)). By contrast, uterine quiescence is maintained throughout most of pregnancy by increased progesterone (P4) levels and enhanced progesterone receptor (PR) activity, which silence expression of proinflammatory mediators and CAP genes. Treatment of pregnant women at risk for preterm labor with progestins has negligible effects - underscoring the need for novel therapeutic targets. To identify such targets, our lab surveyed the myometrial transcriptome of timed-pregnant mice at 15.5-18.5 days post-coitum (dpc) and during labor at term (19.0 dpc) using RNA-sequencing. Interestingly, Cyp27b1 was one of the most highly downregulated transcripts at 18.5 dpc and in-labor, compared to 15.5 dpc. Cyp27b1 encodes 1α-hydroxylase, the key enzyme responsible for synthesis of the active form of vitamin D, 1,25-dihydroxyvitamin D3 (calcitriol) which binds to the vitamin D receptor (VDR). Calcitriol/VDR have anti-inflammatory actions and are reported to mediate maternal tolerance to the hemi-allogeneic fetus. Interestingly, we previously observed that P4 treatment of timed-pregnant mice caused a significant increase in myometrial CYP27B1 mRNA levels, compared to controls. In the present study, we sought to assess effects of calcitriol treatment on CAP gene expression in timed-pregnant mice. To this end, pregnant mice were injected s.c. daily from 13.5-17.5 dpc with vehicle (n=3) of with 3 μg/kg of calcitriol (n=4). Mice were sacrificed and myometrial tissues were collected at 18.5 dpc. RT-qPCR revealed significantly reduced levels of CX43 (p<0.0001) and OXTR (p<0.05) in myometrium of calcitriol treated mice, compared to controls. Collectively, these data suggest that the decrease in Cyp27b1 expression, coupled with the decline in PR function near term may contribute to increased CAP gene expression leading to myometrial contractility and labor. Cyp27b1 may serve as a key P4/PR target gene that acts cooperatively to maintain myometrial quiescence via its anti-inflammatory actions. Thus, calcitriol may be a safe and effective treatment for the prevention of PTB.Item The Murine Amniotic Fluid Macrophage: Upregulation of Classical and Alternative Activation Markers Prior to Labor at Term(2010-11-02) Montalbano, Alina Peraza; Mendelson, Carole R.The initiation of labor at term and preterm is associated with an inflammatory response, with increased interleukins in amniotic fluid (AF) and infiltration of the myometrium by neutrophils and macrophages (MΦ). Whereas, in preterm labor, intra-amniotic infection may provide the inflammatory stimulus for increased AF interleukins and inflammatory cell migration, the stimulus for these events at term has remained unclear. In studies using pregnant mice, we observed that the M that invade the maternal uterus near term originate from the fetus. Furthermore, we obtained compelling evidence that surfactant protein-A (SP-A), a developmentally regulated C-type lectin secreted by the fetal lung into AF near term, activates AF MΦ, which migrate into the pregnant uterus where their local release of interleukin-1 serves to activate nuclear factor kB (NF-kB) pathways. Activation of the NF-kB pathway results in increased expression of genes that promote uterine contractility and negatively impacts the capacity of progesterone receptors to maintain uterine quiescence, culminating in the onset of labor [1]. We propose that interactions of MΦ surface receptors with SP-A, at term, or bacterial lipopolysaccharide at preterm, initiate changes in MΦ phenotypic properties, resulting in the enhanced expression of genes that promote MΦ migration to the uterus. The objectives of this study are: (1) to analyze the phenotypic changes of mouse AF MΦ associated with the developmental induction of SP-A synthesis and secretion by the fetal lung into AF: (2) to determine if SP-A, SP-D, and SP-A/D double deficiencies delay labor at term and to (3) to analyze trafficking patterns of fetal MΦ leading to the induction of labor. The findings presented herein suggest that late gestation AF MΦ upregulate classical and alternative activation markers in tandem as term approaches. Moreover, their phenotypic profile implies that they may modulate both pro- and anti-inflammatory functions simultaneously near term. Trafficking studies using heterozygous fetal-derived amniotic fluid macrophages expressing EGFP under control of the MΦ-specific CSF-1 receptor, demonstrate the absence of this subpopulation in the maternal uterus. Parturition studies in surfactant protein A and -D deficient mice reveal that deficiency in SP-A and –D does not affect the timing of labor. Intriguingly, Toll-like receptor 2 deficient mice demonstrate a delay in the time to parturition pointing to its potential role in mediating a signal for labor at term.Item [News](1983-07-22) Harrell, AnnItem Post-Transcriptional Regulation by microRNAS in Pregnancy and Parturition(2012-08-15) Renthal, Nora Edwards; Mendelson, Carole R.Throughout most of pregnancy, uterine quiescence is maintained by increased progesterone receptor (PR) transcriptional activity, while spontaneous labor is initiated/facilitated by a concerted series of biochemical events that activate inflammatory pathways and negatively impact PR function. In this study, we uncovered a new regulatory pathway whereby miRNAs serve as hormonally-modulated and conserved mediators of contractile gene regulation in the pregnant uterus from mouse to human. Using miRNA and gene expression microarray analyses of uterine tissues, we identified a conserved family of miRNAs, the miR-200 family, that is highly induced at term in both mice and humans, as well as two coordinately downregulated targets, zinc finger E-box binding homeobox proteins, ZEB1 and ZEB2, which act as transcriptional repressors. We also observed upregulation of the miR-200 family and downregulation of ZEB1 and ZEB2 in two different mouse models of preterm labor. We further demonstrated that ZEB1 is directly upregulated by the action of P4/PR at the ZEB1 promoter. Excitingly, we observed that ZEB1 and ZEB2 inhibited expression of the contraction-associated genes, oxytocin receptor and connexin-43 and blocked oxytocin-induced contractility in human myometrial cells. Together, these findings implicate the miR-200 family and their targets ZEB1 and ZEB2 as novel P4/PR-mediated regulators of uterine quiescence and contractility during pregnancy and labor, and shed new light on the molecular mechanisms involved in preterm birth.Item The Role of Vitamin D Metabolism in the Timing of Birth(2018-01-23) Yang, Ailing; Montalbano, Alina; Mendelson, CarolePreterm birth (PTB, <37 weeks of gestation) is the leading cause of neonatal mortality and morbidity. Both term and preterm labor are associated with increased levels of proinflammatory cytokines within fetal and maternal reproductive tissues. Uterine quiescence is maintained throughout most of pregnancy by increased circulating progesterone (P4) and enhanced progesterone receptor (PR) activity, which silence expression of proinflamᆲmatory mediators and contraction-associated genes. To identify novel genes that maintain uterine quiescence during pregnancy and promote the initiation of term and preterm labor, our lab conducted RNA sequencing of myometrium from timed-pregnant mice at 15.5-18.5 days post-coitum (dpc) and during labor (19.0 dpc). Novel genes of interest were identified through transcriptome profiling and validated by quantitative real-time PCR. Cyp27b1 was one of the most highly downregulated transcripts in pregnant mouse myometrium at 18.5 dpc and in-labor, compared to 15.5 dpc. Cyp27b1 1α-hydroxylase, the key enzyme in synthesis of the bioactive form of vitamin D, calcitriol, which binds to the vitamin D receptor (VDR), a member of the steroid/nuclear receptor family, which was also downregulated at term. Calcitriol/VDR mediate anti-inflammatory actions in various tissues; calcitriol synthesized by human placenta, decidual macrophages and uterine natural killer cells was reported to regulate maternal immunologic tolerance to the hemi-allogeneic fetus during pregnancy. The effect of P4 and of the PR antagonist, RU486, on Cyp27b1/VDR mRNA expression was analyzed. We observed that P4 treatment of timed-pregnant mice caused a significant increase in myometrial CYP27B1 mRNA levels compared to time-matched controls in labor at term. In RU486-treated mice, CYP27B1 mRNA decreased signifi-cantly 8 hours post-injection and remained significantly reduced during preterm labor, compared to vehicle-injected mice. Based on these collective findings, we postulate that CYP27B1 and VDR are key P4/PR target genes in the pregnant myometrium that act cooperatively with P4/PR to maintain myometrial quiescence via their anti-inflammatory actions. Thus, the decline in PR function near term, accompanied by a parallel decline in CYP27B1/VDR, permit increased inflammatory gene expression leading to myometrial contractility and labor. We hypothesize that calcitriol may provide a safe and effective treatment for prevention of PTB.Item [UT News](1987-04-29) Harrell, Ann