The hormonal control of parturition.

Parturition is a complex physiological process that must occur in a reliable manner and at an appropriate gestation stage to ensure a healthy newborn and mother. To this end, hormones that affect the function of the gravid uterus, especially progesterone (P4), 17ß-estradiol (E2), oxytocin (OT), and prostaglandins (PGs), play pivotal roles. P4 via the nuclear P4 receptor (PR) promotes uterine quiescence and for most of pregnancy exerts a dominant block to labor. Loss of the P4 block to parturition in association with a gain in prolabor actions of E2 are key transitions in the hormonal cascade leading to parturition. P4 withdrawal can occur through various mechanisms depending on species and physiological context. Parturition in most species involves inflammation within the uterine tissues and especially at the maternal-fetal interface. Local PGs and other inflammatory mediators may initiate parturition by inducing P4 withdrawal. Withdrawal of the P4 block is coordinated with increased E2 actions to enhance uterotonic signals mediated by OT and PGs to promote uterine contractions, cervix softening, and membrane rupture, i.e., labor. This review examines recent advances in research to understand the hormonal control of parturition, with focus on the roles of P4, E2, PGs, OT, inflammatory cytokines, and placental peptide hormones together with evolutionary biology of and implications for clinical management of human parturition.

Progesterone inactivation in decidual stromal cells: A mechanism for inflammation-induced parturition.

The process of human parturition involves inflammation at the interface where fetal chorion trophoblast cells interact with maternal decidual stromal (DS) cells and maternal immune cells in the decidua (endometrium of pregnancy). This study tested the hypothesis that inflammation at the chorion-decidua interface (CDI) induces labor by negating the capacity for progesterone (P4) to block labor and that this is mediated by inactivation of P4 in DS cells by aldo-keto reductase family 1 member C1 (AKR1C1). In human, Rhesus macaque, and mouse CDI, AKR1C1 expression increased in association with term and preterm labor. In a human DS cell line and in explant cultures of term human fetal membranes containing the CDI, the prolabor inflammatory cytokine, interleukin-1ß (IL-1ß), and media conditioned by LPS-stimulated macrophages increased AKR1C1 expression and coordinately reduced nuclear P4 levels and P4 responsiveness. Loss of P4 responsiveness was overcome by inhibition of AKR1C1 activity, inhibition of AKR1C1 expression, and bypassing AKR1C1 activity with a P4 analog that is not metabolized by AKR1C1. Increased P4 activity in response to AKR1C1 inhibition was prevented by the P4 receptor antagonist RU486. Pharmacologic inhibition of AKR1C1 activity prevented parturition in a mouse model of inflammation-induced preterm parturition. The data suggest that inflammatory stimuli at the CDI drive labor by inducing AKR1C1-mediated P4 inactivation in DS cells and that inhibiting and/or bypassing of AKR1C1-mediated P4 inactivation is a plausible therapeutic strategy to mitigate the risk of inflammation-associated preterm birth.

The selective progesterone receptor modulator-promegestone-delays term parturition and prevents systemic inflammation-mediated preterm birth in mice.

BACKGROUND: Progesterone, acting via its nuclear receptors called progesterone receptors, promotes myometrial relaxation during pregnancy, and suspension of this activity triggers labor. We previously found that 20α-hydroxysteroid dehydrogenase causes a local withdrawal of progesterone in the term and preterm myometrium by converting the progesterone into an inactive form before it accesses the progesterone receptors. OBJECTIVE: We hypothesized that a selective progesterone receptor modulator called promegestone, which is not metabolized by 20α-hydroxysteroid dehydrogenase, would sustain progesterone receptor signaling and prevent/delay term labor and preterm labor in mice. STUDY DESIGN: In the term labor mouse model, promegestone (0.2 mg/dam) or a vehicle were administered subcutaneously in timed-pregnant CD-1 mice at gestational days 15, 16, and 17 (term gestational days, 19.5). In the inflammation preterm labor model, pregnant mice received promegestone or a vehicle on gestational days 15, 16, and 17, which was 24 hours before, immediately before, and 24 hours after systemic bacterial endotoxin (50 µg intraperitoneal; lipopolysaccharide group) or vehicle (saline) administration. The maternal and fetal tissues were collected on gestational day 16 6 hours after lipopolysaccharide±promegestone injection and at term gestational day 18.75. The protein levels of 10 cytokines were measured by multiplex immunoassay in maternal plasma and amniotic fluid. Myometrial, decidual, and placental messenger RNA levels of multiple cytokines and procontractile proteins were evaluated by real-time polymerase chain reaction and confirmed by immunoblotting. RESULTS: Promegestone prevented term labor and maintained mice pregnancy postterm >24 hours. The litter size and fetal weights were not different from the controls. Promegestone prevented systemic bacterial-endotoxin-induced preterm labor in 100% of the mice, blocked uterine contractions, significantly inhibited all systemic inflammation-induced myometrial cytokines, and partially inhibited decidual and placental inflammation. Promegestone did not prevent bacterial-endotoxin-induced fetal toxicity. CONCLUSION: Promegestone a selective progesterone receptor modulator that binds progesterone receptors with high affinity and is not metabolized by 20α-hydroxysteroid dehydrogenase could completely suppress term parturition and systemic bacterial-endotoxin-induced preterm birth in mice. We suggest that such selective progesterone receptor modulators may represent a potential therapeutic approach to the prevention of preterm labor in women at high risk of preterm birth.

Pro-inflammatory signals induce 20α-HSD expression in myometrial cells: A key mechanism for local progesterone withdrawal.

Metabolism of progesterone (P4) by the enzyme 20α hydroxysteroid dehydrogenase (20α-HSD) in myometrial cells is postulated to be a mechanism for P4 withdrawal, which occurs concomitant to uterine inflammation (physiologic or infection-induced) and associated activation of transcription factors: NF-кB and AP-1, common to term and preterm labour. We found that 20α-HSD protein is significantly increased in human myometrium during term labour, and in mouse uterus during term and preterm labour. Treatment of human myometrial cells with the pro-inflammatory mediators, lipopolysaccharide (LPS, mimicking infection) and 12-O-tetradecanoylphorbol-13-acetate (TPA, mimicking inflammation), induced 20α-HSD gene expression and increased 20α-HSD protein abundance. LPS treatment decreased P4 release into the culture medium and resulted in up-regulation of GJA1 in the hTERT-HM cells. The NF-кB /AP-1 transcription factors mediated effects of LPS and TPA on 20α-HSD gene transcription. Both pro-inflammatory stimuli induced 20α-HSD promoter activity in LPS/TPA-treated cells which was significantly attenuated by inhibition of NF-кB (JSH: 20 µM) or AP-1 signalling (T5224: 10 µM). Deletion of NF-кB consensus sites abrogated LPS-mediated promoter induction, while removal of AP-1 sites reversed the TPA-mediated induction of 20α-HSD promoter. We conclude that inflammatory stimuli (physiologic or pathologic) that activate NF-кB or AP-1 induce 20α-HSD transcription and subsequent local P4 withdrawal resulting in up-regulation of GJA1 and activation of myometrium that precedes labour.

Natural Selection Has Differentiated the Progesterone Receptor among Human Populations.

The progesterone receptor (PGR) plays a central role in maintaining pregnancy and is significantly associated with medical conditions such as preterm birth that affects 12.6% of all the births in U.S. PGR has been evolving rapidly since the common ancestor of human and chimpanzee, and we herein investigated evolutionary dynamics of PGR during recent human migration and population differentiation. Our study revealed substantial population differentiation at the PGR locus driven by natural selection, where very recent positive selection in East Asians has substantially decreased its genetic diversity by nearly fixing evolutionarily novel alleles. On the contrary, in European populations, the PGR locus has been promoted to a highly polymorphic state likely due to balancing selection. Integrating transcriptome data across multiple tissue types together with large-scale genome-wide association data for preterm birth, our study demonstrated the consequence of the selection event in East Asians on remodeling PGR expression specifically in the ovary and determined a significant association of early spontaneous preterm birth with the evolutionarily selected variants. To reconstruct its evolutionary trajectory on the human lineage, we observed substantial differentiation between modern and archaic humans at the PGR locus, including fixation of a deleterious missense allele in the Neanderthal genome that was later introgressed in modern human populations. Taken together, our study revealed substantial evolutionary innovation in PGR even during very recent human evolution, and its different forms among human populations likely result in differential susceptibility to progesterone-associated disease conditions including preterm birth.

Superovulation with human chorionic gonadotropin (hCG) trigger and gonadotropin releasing hormone agonist (GnRHa) trigger differentially alter essential angiogenic factors in the endometrium in a mouse ART model†.

Gonadotropin-releasing hormone agonists (GnRHa) are used as an alternative to human chorionic gonadotropin (hCG) to trigger ovulation and decrease the risk of ovarian hyperstimulation syndrome. GnRHa is less potent at inducing ovarian vascular endothelial growth factor (VEGF), but may also affect endometrial angiogenesis and early placental development. In this study, we explore the effect of superovulation on endometrial angiogenesis during critical periods of gestation in a mouse model. We assigned female mice to three groups: natural mating or mating following injection with equine chorionic gonadotropin and trigger with GnRHa or hCG trigger. Females were killed prior to implantation (E3.5), post-implantation (E7.5), and at midgestation (E10.5), and maternal serum, uterus, and ovaries were collected. During peri-implantation, endometrial Vegfr1 and Vegfr2 mRNA were significantly increased in the GnRHa trigger group (P < 0.02) relative to the hCG group. Vegfr1 is highly expressed in the endometrial lining and secretory glands immediately prior to implantation. At E7.5, the ectoplacental cone expression of Vegfa and its receptor, Vegfr2, was significantly higher in the hCG trigger group compared to the GnRHa group (P < 0.05). Soluble VEGFR1 and free VEGFA were much higher in the serum of mice exposed to the hCG trigger compared to GnRHa group. At midgestation, there was significantly more local Vegfa expression in the placenta of mice triggered with hCG. GnRHa and hCG triggers differentially disrupt the endometrial expression of key angiogenic factors during critical periods of mouse gestation. These results may have significant implications for placental development and neonatal outcomes following human in vitro fertilization.

Advancing human health in the decade ahead: pregnancy as a key window for discovery: A Burroughs Wellcome Fund Pregnancy Think Tank.

Recent revolutionary advances at the intersection of medicine, omics, data sciences, computing, epidemiology, and related technologies inspire us to ponder their impact on health. Their potential impact is particularly germane to the biology of pregnancy and perinatal medicine, where limited improvement in health outcomes for women and children has remained a global challenge. We assembled a group of experts to establish a Pregnancy Think Tank to discuss a broad spectrum of major gestational disorders and adverse pregnancy outcomes that affect maternal-infant lifelong health and should serve as targets for leveraging the many recent advances. This report reflects avenues for future effects that hold great potential in 3 major areas: developmental genomics, including the application of methodologies designed to bridge genotypes, physiology, and diseases, addressing vexing questions in early human development; gestational physiology, from immune tolerance to growth and the timing of parturition; and personalized and population medicine, focusing on amalgamating health record data and deep phenotypes to create broad knowledge that can be integrated into healthcare systems and drive discovery to address pregnancy-related disease and promote general health. We propose a series of questions reflecting development, systems biology, diseases, clinical approaches and tools, and population health, and a call for scientific action. Clearly, transdisciplinary science must advance and accelerate to address adverse pregnancy outcomes. Disciplines not traditionally involved in the reproductive sciences, such as computer science, engineering, mathematics, and pharmacology, should be engaged at the study design phase to optimize the information gathered and to identify and further evaluate potentially actionable therapeutic targets. Information sources should include noninvasive personalized sensors and monitors, alongside instructive "liquid biopsies" for noninvasive pregnancy assessment. Future research should also address the diversity of human cohorts in terms of geography, racial and ethnic distributions, and social and health disparities. Modern technologies, for both data-gathering and data-analyzing, make this possible at a scale that was previously unachievable. Finally, the psychosocial and economic environment in which pregnancy takes place must be considered to promote the health and wellness of communities worldwide.

Steroid Hormone Levels in Recipient Amniotic Fluid in Twin-Twin Transfusion Syndrome and Their Association with Preterm Delivery.

OBJECTIVE: Preterm delivery following fetoscopic laser surgery (FLS) of twin-twin transfusion syndrome (TTTS) is associated with severe perinatal morbidity and mortality. The role of steroid hormones in amniotic fluid (AF) after FLS remains unknown. STUDY DESIGN: A prospective cohort study of consecutive case series of FLS for TTTS was performed from April 2012 to February 2017. Cases were divided into early (≤27 weeks) spontaneous preterm delivery (ED) and late delivery (LD; ≥34 weeks) following FLS and compared. AF supernatants were assessed for protein, estradiol, progesterone and cortisol levels (using the ELISA kit), and normalized to total protein levels to adjust for dilution. RESULTS: A total of 294 consecutive cases of FLS for TTTS in monochorionic-diamniotic twins were performed during the study period. AF was available in 44 ED patients and 50 LD patients. On logistic regression, ED was associated with higher normalized progesterone levels (odds ratio [OR]: 1.25; 95% confidence interval [CI]: 1.12-1.41), lower normalized cortisol (OR: 0.78; 95% CI: 0.64-0.96), and higher estradiol levels (OR: 1.3; 95% CI: 1.03-1.63). CONCLUSION: Elevated AF normalized progesterone and estradiol, and lower normalized cortisol levels were associated with ED. This novel finding requires further exploration to establish the molecular mechanism operational in pregnancies complicated by TTTS to potentially prevent early preterm birth after fetal surgery.

Interplay of transcriptional signaling by progesterone, cyclic AMP, and inflammation in myometrial cells: implications for the control of human parturition.

Parturition involves cellular signaling changes driven by the complex interplay between progesterone (P4), inflammation, and the cyclic adenosine monophosphate (cAMP) pathway. To characterize this interplay, we performed comprehensive transcriptomic studies utilizing eight treatment combinations on myometrial cell lines and tissue samples from pregnant women. We performed genome-wide RNA-sequencing on the hTERT-HM${}^{A/B}$ cell line treated with all combinations of P4, forskolin (FSK) (induces cAMP), and interleukin-1$\beta$ (IL-1$\beta$). We then performed gene set enrichment and regulatory network analyses to identify pathways commonly, differentially, or synergistically regulated by these treatments. Finally, we used tissue similarity index (TSI) to characterize the correspondence between cell lines and tissue phenotypes. We observed that in addition to their individual anti-inflammatory effects, P4 and cAMP synergistically blocked specific inflammatory pathways/regulators including STAT3/6, CEBPA/B, and OCT1/7, but not NF$\kappa$B. TSI analysis indicated that FSK + P4- and IL-1$\beta$-treated cells exhibit transcriptional signatures highly similar to non-laboring and laboring term myometrium, respectively. Our results identify potential therapeutic targets to prevent preterm birth and show that the hTERT-HM${}^{A/B}$ cell line provides an accurate transcriptional model for term myometrial tissue.

Finding lost genes in GWAS via integrative-omics analysis reveals novel sub-networks associated with preterm birth.

Maternal genome influences associate with up to 40% of spontaneous preterm births (PTB). Multiple genome wide association studies (GWAS) have been completed to identify genetic variants associated with PTB. Disappointingly, no highly significant SNPs have replicated in independent cohorts so far. We developed an approach combining protein-protein interaction (PPI) network data with tissue specific gene expression data to "find" SNPs of modest significance to identify candidate genes of functional importance that would otherwise be overlooked. This approach is based on the assumption that "high-ranking" SNPs falling short of genome wide significance may nevertheless indicate genes that have substantial biological value in understanding PTB. We mapped highly-ranked candidate SNPs from a meta-analysis of PTB-GWAS to coding genes and developed a PPI network enriched with PTB-SNP carrying genes. This network was scored with gene expression data from term and preterm myometrium to identify subnetworks of PTB-SNP associated genes coordinately expressed with labour onset in myometrial tissue. Our analysis consistently identified significant sub-networks associated with the interacting transcription factors MEF2C and TWIST1, genes not previously associated with PTB, both of which regulate processes clearly relevant to birth timing. Other genes in the significant sub-networks were also associated with inflammatory pathways, as well as muscle function and ion channels. Gene expression level dysregulation was confirmed for eight of these networks by qRT-PCR in an independent set of term and pre-term subjects. Our method identifies novel genes dysregulated in PTB and provides a generalized framework to identify GWAS SNPs that would otherwise be overlooked.

Integrated microRNA and mRNA network analysis of the human myometrial transcriptome in the transition from quiescence to labor.

We conducted integrated transcriptomics network analyses of miRNA and mRNA interactions in human myometrium to identify novel molecular candidates potentially involved in human parturition. Myometrial biopsies were collected from women undergoing primary Cesarean deliveries in well-characterized clinical scenarios: (1) spontaneous term labor (TL, n = 5); (2) term nonlabor (TNL, n = 5); (3) spontaneous preterm birth (PTB) with histologic chorioamnionitis (PTB-HCA, n = 5); and (4) indicated PTB nonlabor (PTB-NL, n = 5). RNAs were profiled using RNA sequencing, and miRNA-target interaction networks were mined for key discriminatory subnetworks. Forty miRNAs differed between TL and TNL myometrium, while seven miRNAs differed between PTB-HCA vs. PTB-NL specimens; six of these were cross-validated using quantitative PCR. Based on the combined sequencing data, unsupervised clustering revealed two nonoverlapping cohorts that differed primarily by absence or presence of uterine quiescence, rather than gestational age or original clinical cohort. The intersection of differentially expressed miRNAs and their targets predicted 22 subnetworks with enriched representation of miR-146b-5p, miR-223-3p, and miR-150-5p among miRNAs, and of myocyte enhancer factor-2C (MEF2C) among mRNAs. Of four known MEF2 transcription factors, decreased MEF2A and MEF2C expression in women with uterine nonquiescence was observed in the sequencing data, and validated in a second cohort by quantitative PCR. Immunohistochemistry localized MEF2A and MEF2C to myometrial smooth muscle cells and confirmed decreased abundance with labor. Collectively, these results suggest altered MEF2 expression may represent a previously unrecognized process through which miRNAs contribute to the phenotypic switch from quiescence to labor in human myometrium.

Progesterone, the maternal immune system and the onset of parturition in the mouse.

The role of progesterone (P4) in the regulation of the local (uterine) and systemic innate immune system, myometrial expression of connexin 43 (Cx-43) and cyclooxygenase 2 (COX-2), and the onset of parturition was examined in (i) naïve mice delivering at term; (ii) E16 mice treated with RU486 (P4-antagonist) to induce preterm parturition; and (iii) in mice treated with P4 to prevent term parturition. In naïve mice, myometrial neutrophil and monocyte numbers peaked at E18 and declined with the onset of parturition. In contrast, circulating monocytes did not change and although neutrophils were increased with pregnancy, they did not change across gestation. The myometrial mRNA and protein levels of most chemokines/cytokines, Cx-43, and COX-2 increased with, but not before, parturition. With RU486-induced parturition, myometrial and systemic neutrophil numbers increased before and myometrial monocyte numbers increased with parturition only. Myometrial chemokine/cytokine mRNA abundance increased with parturition, but protein levels peaked earlier at between 4.5 and 9 h post-RU486. Cx-43, but not COX-2, mRNA expression and protein levels increased prior to the onset of parturition. In mice treated with P4, the gestation-linked increase in myometrial monocyte, but not neutrophil, numbers was prevented, and expression of Cx-43 and COX-2 was reduced. On E20 of P4 supplementation, myometrial chemokine/cytokine and leukocyte numbers, but not Cx-43 and COX-2 expression, increased. These data show that during pregnancy P4 controls myometrial monocyte infiltration, cytokine and prolabor factor synthesis via mRNA-dependent and independent mechanisms and, with prolonged P4 supplementation, P4 action is repressed resulting in increased myometrial inflammation.

Amnion epithelial cell-derived exosomes induce inflammatory changes in uterine cells.

BACKGROUND: Fetal endocrine signals are generally considered to contribute to the timing of birth and the initiation of labor. Fetal tissues under oxidative stress release inflammatory mediators that lead to sterile inflammation within the maternal-fetal interface. Importantly, these inflammatory mediators are packaged into exosomes, bioactive cell-derived extra cellular vesicles that function as vectors and transport them from the fetal side to the uterine tissues where they deposit their cargo into target cells enhancing uterine inflammatory load. This exosome-mediated signaling is a novel mechanism for fetal-maternal communication. OBJECTIVE: This report tested the hypothesis that oxidative stress can induce fetal amnion cells to produce exosomes, which function as a paracrine intermediary between the fetus and mother and biochemically signal readiness for parturition. STUDY DESIGN: Primary amnion epithelial cells were grown in normal cell culture (control) or exposed to oxidative stress conditions (induced by cigarette smoke extract). Exosomes were isolated from cell supernatant by sequential ultracentrifugation. Exosomes were quantified and characterized based on size, shape, and biochemical markers. Myometrial, decidual, and placental cells (BeWo) were treated with 2 × 105, 2 × 107, and 2 × 109 control or oxidative stress-derived amnion epithelial cell exosomes for 24 hours. Entry of amnion epithelial cell exosomes into cells was confirmed by confocal microscopy of fluorescent-labeled exosomes. The effect of amnion epithelial cell exosomes on target cell inflammatory status was determined by measuring production of interleukin-6, interleukin-8, interleukin-1ß, tumor necrosis factor-α, and prostaglandin E2 by enzyme-linked immunosorbent assay and inflammatory gene transcription factor (nuclear factor-κß) activation status by immunoblotting for phosphorylated RelA/p65. Localization of NANOG in term human myometrium and decidua obtained from women before labor and during labor was performed using immunohistochemistry. Data were analyzed by Wilcoxon-Mann-Whitney test to compare effects of exosomes from control and oxidative stress-treated amnion epithelial cells on inflammatory status of target cells. RESULTS: Amnion epithelial cells released ∼125 nm, cup-shaped exosomes with ∼899 and 1211 exosomes released per cell from control and oxidative stress-induced cells, respectively. Amnion epithelial cell exosomes were detected in each target cell type after treatment using confocal microscopy. Treatment with amnion epithelial cell exosomes increased secretion of interleukin-6, interleukin-8, and PGE2 and activation of NF-κß (each P < .05) in myometrial and decidual cells. Exosome treatments had no effect on interleukin-6 and PGE2 production in BeWo cells. NANOG staining was higher in term labor myometrium and decidua compared to tissues not in labor. CONCLUSION: In vitro, amnion epithelial cell exosomes lead to an increased inflammatory response in maternal uterine cells whereas placental cells showed refractoriness. Fetal cell exosomes may function to signal parturition by increasing maternal gestational cell inflammation.

In an in-vitro model using human fetal membranes, 17-α hydroxyprogesterone caproate is not an optimal progestogen for inhibition of fetal membrane weakening.

BACKGROUND: The progestogen 17-α hydroxyprogesterone caproate (17-OHPC) is 1 of only 2 agents recommended for clinical use in the prevention of spontaneous preterm delivery, and studies of its efficacy have been conflicting. We have developed an in-vitro model to study the fetal membrane weakening process that leads to rupture in preterm premature rupture of the fetal membranes (pPROM). Inflammation/infection associated with tumor necrosis factor-α (TNF-α) induction and decidual bleeding/abruption associated thrombin release are leading causes of preterm premature rupture of the fetal membranes. Both agents (TNF-α and thrombin) cause fetal membrane weakening in the model system. Furthermore, granulocyte-macrophage colony-stimulating factor (GM-CSF) is a critical intermediate for both TNF-α and thrombin-induced fetal membrane weakening. In a previous report, we demonstrated that 3 progestogens, progesterone, 17-alpha hydroxyprogesterone (17-OHP), and medroxyprogesterone acetate (MPA), each inhibit both TNF-α- and thrombin-induced fetal membrane weakening at 2 distinct points of the fetal membrane weakening pathway. Each block both the production of and the downstream action of the critical intermediate granulocyte-macrophage colony-stimulating factor. OBJECTIVE: The objective of the study was to characterize the inhibitory effects of 17-OHPC on TNF-α- and thrombin-induced fetal membrane weakening in vitro. STUDY DESIGN: Full-thickness human fetal membrane fragments from uncomplicated term repeat cesarean deliveries were mounted in 2.5 cm Transwell inserts and cultured with/without 17-alpha hydroxyprogesterone caproate (10-9 to 10-7 M). After 24 hours, medium (supernatant) was removed and replaced with/without the addition of tumor necrosis factor-alpha (20 ng/mL) or thrombin (10 U/mL) or granulocyte-macrophage colony-stimulating factor (200 ng/mL). After 48 hours of culture, medium from the maternal side compartment of the model was assayed for granulocyte-macrophage colony-stimulating factor and the fetal membrane fragments were rupture strength tested. RESULTS: Tumor necrosis factor-alpha and thrombin both weakened fetal membranes (43% and 62%, respectively) and increased granulocyte-macrophage colony-stimulating factor levels (3.7- and 5.9-fold, respectively). Pretreatment with 17-alpha hydroxyprogesterone caproate inhibited both tumor necrosis factor-alpha- and thrombin-induced fetal membrane weakening and concomitantly inhibited the induced increase in granulocyte-macrophage colony-stimulating factor in a concentration-dependent manner. However, contrary to our prior reports regarding progesterone and other progestogens, 17-alpha hydroxyprogesterone caproate did not also inhibit granulocyte-macrophage colony-stimulating factor-induced fetal membrane weakening. CONCLUSION: 17-Alpha hydroxyprogesterone caproate blocks tumor necrosis factor-alpha- and thrombin-induced fetal membrane weakening by inhibiting the production of granulocyte-macrophage colony-stimulating factor. However, 17-alpha hydroxyprogesterone caproate did not also inhibit granulocyte-macrophage colony-stimulating factor-induced weakening. We speculate that progestogens other than 17-alpha hydroxyprogesterone caproate may be more efficacious in preventing preterm premature rupture of the fetal membranes-related spontaneous preterm birth.

Progesterone inhibits in vitro fetal membrane weakening.

OBJECTIVE: Inflammation/infection and abruption are leading causes of preterm premature rupture of the membranes. Recently, we identified granulocyte-macrophage colony-stimulating factor (GM-CSF) as a critical mediator of both tumor necrosis factor-α- (TNF; modeling inflammation) and thrombin-induced (modeling abruption) weakening of the fetal membranes. We found that (1) TNF and thrombin both induced GM-CSF in the choriodecidua, (2) blockade of GM-CSF action with neutralizing antibodies inhibited both TNF- and thrombin-induced fetal membrane weakening, and (3) GM-CSF alone induced fetal membrane weakening. GM-CSF is thus part of an overlap of the inflammation and abruption-induced fetal membrane weakening pathways. The effects of progesterone analogs on the pathways by which fetal membranes are weakened have not been investigated. We examined the effects of progesterone, medroxyprogesterone acetate (MPA) and 17α-hydroxyprogesterone (HP) on TNF- and thrombin-induced fetal membrane weakening. STUDY DESIGN: Full-thickness fetal membranes from uncomplicated term repeat cesarean deliveries were mounted in Transwell inserts in Minimum Essential Medium alpha and incubated at 37°C in 5% CO2. The choriodecidua side of the fetal membrane fragments were preincubated with progesterone, MPA, HP, or vehicle for 24 hours. Fetal membranes were then exposed to TNF, thrombin, or GM-CSF on the choriodecidua side for an additional 48 hours. The fetal membrane tissues were then strength tested, and medium from the choriodecidua and amnion compartments was assayed for GM-CSF content. RESULTS: TNF and thrombin both weakened fetal membranes and elevated media GM-CSF levels on the choriodecidua side of the fetal membrane. Pretreatment with progesterone, MPA, or HP inhibited both TNF- and thrombin-induced fetal membrane weakening and also inhibited the induced increase in GM-CSF. GM-CSF decreased fetal membrane rupture strength by 68%, which was inhibited by progestogen pretreatment with a potency order: progesterone

Magnesium decreases inflammatory cytokine production: a novel innate immunomodulatory mechanism.

MgSO(4) exposure before preterm birth is neuroprotective, reducing the risk of cerebral palsy and major motor dysfunction. Neonatal inflammatory cytokine levels correlate with neurologic outcome, leading us to assess the effect of MgSO(4) on cytokine production in humans. We found reduced maternal TNF-α and IL-6 production following in vivo MgSO(4) treatment. Short-term exposure to a clinically effective MgSO(4) concentration in vitro substantially reduced the frequency of neonatal monocytes producing TNF-α and IL-6 under constitutive and TLR-stimulated conditions, decreasing cytokine gene and protein expression, without influencing cell viability or phagocytic function. In summary, MgSO(4) reduced cytokine production in intrapartum women, term and preterm neonates, demonstrating effectiveness in those at risk for inflammation-associated adverse perinatal outcomes. By probing the mechanism of decreased cytokine production, we found that the immunomodulatory effect was mediated by magnesium and not the sulfate moiety, and it was reversible. Cellular magnesium content increased rapidly upon MgSO(4) exposure, and reduced cytokine production occurred following stimulation with different TLR ligands as well as when magnesium was added after TLR stimulation, strongly suggesting that magnesium acts intracellularly. Magnesium increased basal IĸBα levels, and upon TLR stimulation was associated with reduced NF-κB activation and nuclear localization. These findings establish a new paradigm for innate immunoregulation, whereby magnesium plays a critical regulatory role in NF-κB activation, cytokine production, and disease pathogenesis.

Integrative analysis of noncoding mutations identifies the druggable genome in preterm birth.

Preterm birth affects ~10% of pregnancies in the US. Despite familial associations, identifying at-risk genetic loci has been challenging. We built deep learning and graphical models to score mutational effects at base resolution via integrating the pregnant myometrial epigenome and large-scale patient genomes with spontaneous preterm birth (sPTB) from European and African American cohorts. We uncovered previously unidentified sPTB genes that are involved in myometrial muscle relaxation and inflammatory responses and that are regulated by the progesterone receptor near labor onset. We studied genomic variants in these genes in our recruited pregnant women administered progestin prophylaxis. We observed that mutation burden in these genes was predictive of responses to progestin treatment for preterm birth. To advance therapeutic development, we screened ~4000 compounds, identified candidate molecules that affect our identified genes, and experimentally validated their therapeutic effects on regulating labor. Together, our integrative approach revealed the druggable genome in preterm birth and provided a generalizable framework for studying complex diseases.

Proteoglycans of uterine fibroids and keloid scars: similarity in their proteoglycan composition.

Fibrosis is the formation of excess and abnormal fibrous connective tissue as a result of either a reparative or reactive process. A defining feature of connective tissue is its extracellular matrix, which provides structural support and also influences cellular activity. Two common human conditions that result from fibrosis are uterine fibroids (leiomyomas) and keloid scars. Because these conditions share a number of similarities and because their growth is due primarily to excessive extracellular matrix deposition, we compared the proteoglycans of uterine fibroids and keloid scars with corresponding normal tissues. Our analysis indicates that uterine fibroids and keloid scars contain higher amounts of glycosaminoglycans relative to normal myometrium and normal adult skin respectively. Proteoglycan composition is also different in the fibrotic tissues. Compared with unaffected tissues, uterine fibroids and keloid scars contain higher relative amounts of versican and lower relative amounts of decorin. There is also evidence for a higher level of versican catabolism in the fibrotic tissues compared with unaffected tissues. These qualitative and quantitative proteoglycan differences may play a role in the expansion of these fibroses and in their excessive matrix deposition and matrix disorganization, due to effects on cell proliferation, TGF (transforming growth factor)-ß signalling and/or collagen fibril formation.

A microbiota and dietary metabolite integrates DNA repair and cell death to regulate embryo viability and aneuploidy during aging.

During aging, environmental stressors and mutations along with reduced DNA repair cause germ cell aneuploidy and genome instability, which limits fertility and embryo development. Benevolent commensal microbiota and dietary plants secrete indoles, which improve healthspan and reproductive success, suggesting regulation of germ cell quality. We show that indoles prevent aneuploidy and promote DNA repair and embryo viability, which depends on age and genotoxic stress levels and affects embryo quality across generations. In young animals or with low doses of radiation, indoles promote DNA repair and embryo viability; however, in older animals or with high doses of radiation, indoles promote death of the embryo. These studies reveal a previously unknown quality control mechanism by which indole integrates DNA repair and cell death responses to preclude germ cell aneuploidy and ensure transgenerational genome integrity. Such regulation affects healthy aging, reproductive senescence, cancer, and the evolution of genetic diversity in invertebrates and vertebrates.