Association between miRNAs in serum at 10-14 gestational weeks and spontaneous preterm delivery.

INTRODUCTION: Preterm delivery (PTD) is the leading cause of death in children under 5 years of age. Cervical shortening detected by ultrasound can be used to predict PTD, but prediction is not perfect, and complementary diagnostic markers are needed. Recently, specific plasma microribonucleic acid (miRNAs) detected in early second trimester were shown to be associated with spontaneous PTD in high-risk women with a singleton pregnancy. The aim of this study was to explore to what extent these miRNAs are associated with spontaneous PTD and cervical length in a general population. MATERIAL AND METHODS: This study is a nested case-control study within the CERVIX study. The CERVIX study evaluated the ability of cervical length screening with transvaginal ultrasound to identify women at risk of PTD. In the present study, women who delivered spontaneously <34 weeks (n = 61) were compared with a control group of women who delivered at full term (39 + 0 to 40 + 6 gestational weeks, n = 205). Archived serum samples were analyzed with RT-qPCR for miRNA expression levels of let-7a-5p, miR-150-5p, miR-15b-5p, miR-185-5p, miR-191-5p, miR-19b-3p, miR-23a-3p, miR-374a-5p, and miR-93-5p. The mean relative expression was compared between the groups. Sub-analyses were performed for women delivering <32, <30, and <28 weeks vs the full-term group. RESULTS: The analyzed miRNAs were not significantly differentially expressed in women delivering <34 weeks compared to those delivering at full term. MiR-191-5p and miR-93-5p were significantly overexpressed in women who delivered <32 weeks, and further increase in fold change was observed with decreasing gestational age at delivery. The level of miR-15b-5p was significantly higher in women delivering at <30 weeks compared to those delivering at full term. CONCLUSIONS: Our study shows that overexpression of miR-93-5p, miR-15b-5p, and miR-191-5p in serum at early gestation is associated with spontaneous PTD in a general population. Further research is needed to evaluate the potential of these miRNAs as future biomarkers for spontaneous PTD, as well as their pathophysiological role in spontaneous PTD.

Diabetes and anti-diabetic interventions and the risk of gynaecological and obstetric morbidity: an umbrella review of the literature.

BACKGROUND: Diabetes has reached epidemic proportions in recent years with serious health ramifications. The aim of this study was to evaluate the strength and validity of associations between diabetes and anti-diabetic interventions and the risk of any type of gynaecological or obstetric conditions. METHODS: Design: Umbrella review of systematic reviews and meta-analyses. DATA SOURCES: PubMed, Medline, Embase, Cochrane Database of Systematic Reviews, manual screening of references. ELIGIBILITY CRITERIA: Systematic reviews and meta-analyses of observational and interventional studies investigating the relationship between diabetes and anti-diabetic interventions with gynaecological or obstetric outcomes. Meta-analyses that did not include complete data from individual studies, such as relative risk, 95% confidence intervals, number of cases/controls, or total population were excluded. DATA ANALYSIS: The evidence from meta-analyses of observational studies was graded as strong, highly suggestive, suggestive or weak according to criteria comprising the random effects estimate of meta-analyses and their largest study, the number of cases, 95% prediction intervals, I2 heterogeneity index between studies, excess significance bias, small study effect and sensitivity analysis using credibility ceilings. Interventional meta-analyses of randomised controlled trials were assessed separately based on the statistical significance of reported associations, the risk of bias and quality of evidence (GRADE) of included meta-analyses. RESULTS: A total of 117 meta-analyses of observational cohort studies and 200 meta-analyses of randomised clinical trials that evaluated 317 outcomes were included. Strong or highly suggestive evidence only supported a positive association between gestational diabetes and caesarean section, large for gestational age babies, major congenital malformations and heart defects and an inverse relationship between metformin use and ovarian cancer incidence. Only a fifth of the randomised controlled trials investigating the effect of anti-diabetic interventions on women's health reached statistical significance and highlighted metformin as a more effective agent than insulin on risk reduction of adverse obstetric outcomes in both gestational and pre-gestational diabetes. CONCLUSIONS: Gestational diabetes appears to be strongly associated with a high risk of caesarean section and large for gestational age babies. Weaker associations were demonstrated between diabetes and anti-diabetic interventions with other obstetric and gynaecological outcomes. TRIAL REGISTRATION: Open Science Framework (OSF) (Registration https://doi.org/10.17605/OSF.IO/9G6AB ).

The early determinants of career choices for medical students following an obstetrics and gynaecology placement: Mixed methods study.

OBJECTIVE: To explore the impact of attending a clinical placement in considering a career in obstetrics and gynaecology. DESIGN: Mixed methods study. SETTING: London Medical School. POPULATION: Fifth year medical students attending a clinical placement in obstetrics and gynaecology. METHODS: Between January 2021 and January 2022, questionnaires were used and semi-structured focus groups conducted, which were audio-recorded. Descriptive statistics were conducted and a framework analysis on transcribed focus groups. MAIN OUTCOME MEASURE: The impact of the clinical placement on career choice. RESULTS: Six main themes were identified from the analysis; three contributing to considering a career in obstetrics and gynaecology; pregnancy is not an illness, extraordinary experience of observing childbirth and variable specialty and three themes emerged contributing to not considering a career; lack of work-life balance, high stakes specialty and the emotional toll. Even at an undergraduate level, medical students exhibited concerns about the long-term feasibility of achieving work-life balance and avoiding professional burnout, which was partly attributed to the responsibility of looking after both the woman and their baby. CONCLUSIONS: Obstetrics and gynaecology is perceived as an exciting and variable speciality by medical students. Students' experiences on the labour ward during a clinical placement appear to contribute to the consideration of a career in obstetrics and gynaecology. Students should be given opportunities to discuss their concerns about obstetrics, particularly over the potential psychological impact of adverse/traumatic birth events. It is crucial to provide a realistic introduction to obstetrics, to recruit enthusiastic junior doctors who will be resilient to the pressures of the speciality, to avoid burnout and minimise attrition rates.

Cervical length and quantitative fetal fibronectin in the prediction of spontaneous preterm birth in asymptomatic women with congenital uterine anomaly.

BACKGROUND: Congenital uterine anomalies are associated with late miscarriage and spontaneous preterm birth. OBJECTIVE: Our aim was 1) to determine the rate of spontaneous preterm birth in each type of congenital uterine anomaly, and 2) to assess the performance of quantitative fetal fibronectin and cervical length measurement by transvaginal ultrasound in asymptomatic women with congenital uterine anomalies for the prediction of spontaneous preterm birth at <34 and <37 weeks of gestation. MATERIALS AND METHODS: This was a retrospective cohort of women with congenital uterine anomalies asymptomatic for spontaneous preterm birth, from 4 tertiary referral centers in the United Kingdom (2001-2016). Congenital uterine anomalies were categorized into fusion (unicornuate, didelphic, and bicornuate uteri) or resorption defects (septate, with or without resection, and arcuate uteri), based on prepregnancy diagnosis. All women underwent serial transvaginal ultrasound cervical length assessment in the second trimester (16 to 24 weeks' gestation); a subgroup underwent quantitative fetal fibronectin testing from 18 weeks' gestation. We investigated the relationship between congenital uterine anomalies and predictive test performance for spontaneous preterm birth at <34 and <37 weeks' gestation. RESULTS: A total of 319 women were identified as having congenital uterine anomalies in our high-risk population. Of the women, 7% (23/319) delivered spontaneously at <34 weeks' gestation and 18% (56/319) at <37 weeks' gestation. Rates of spontaneous preterm birth by type were as follows: 26% (7/27) for unicornuate, 21% (7/34) for didelphic, 16% (31/189) for bicornuate, 13% (7/56) for septate, and 31% (4/13) for arcuate. In all, 80% (45/56) of women who had spontaneous preterm birth at <37 weeks did not develop a short cervical length (<25 mm) during the surveillance period (16-24 weeks). The diagnostic accuracy of short cervical length had a low sensitivity (20.3) for predicting spontaneous preterm birth at <34 weeks. Cervical length had an area under the receiver operating curve of 0.56 (95% confidence interval, 0.48-0.64) and 0.59 (95% confidence interval, 0.55-0.64) for prediction of spontaneous preterm birth at <34 and <37 weeks, respectively. The area under the curve for cervical length to predict spontaneous preterm birth at <34 weeks was 0.48 for fusion defects (95% confidence interval, 0.39-0.57) but 0.78 (95% confidence interval, 0.66-0.91) for women with resorption defects. Overall quantitative fetal fibronectin had an area under the curve of 0.63 (95% confidence interval, 0.49-0.77) and 0.58 (95% confidence interval, 0.49- 0.68) for prediction of spontaneous preterm birth at <34 and <37 weeks, respectively. The area under the curve for prediction of spontaneous preterm birth at <37 weeks with quantitative fetal fibronectin for fusion defects was 0.52 (95% confidence interval, 0.41-0.63) but 0.79 (95% confidence interval, 0.63-0.95) for women with resorption defects. Results were similar when women with intervention were excluded. CONCLUSION: The commonly used markers cervical length and quantitative fetal fibronectin have utility in prediction of spontaneous preterm birth in resorption congenital uterine defects but not in fusion defects. This is contrary to findings in other high-risk populations. These findings need to be accounted for when planning antenatal care, and have potential implications for predictive tests used in spontaneous preterm birth surveillance and intervention.

Vaginal dysbiosis increases risk of preterm fetal membrane rupture, neonatal sepsis and is exacerbated by erythromycin.

BACKGROUND: Preterm prelabour rupture of the fetal membranes (PPROM) precedes 30% of preterm births and is a risk factor for early onset neonatal sepsis. As PPROM is strongly associated with ascending vaginal infection, prophylactic antibiotics are widely used. The evolution of vaginal microbiota compositions associated with PPROM and the impact of antibiotics on bacterial compositions are unknown. METHODS: We prospectively assessed vaginal microbiota prior to and following PPROM using MiSeq-based sequencing of 16S rRNA gene amplicons and examined the impact of erythromycin prophylaxis on bacterial load and community structures. RESULTS: In contrast to pregnancies delivering at term, vaginal dysbiosis characterised by Lactobacillus spp. depletion was present prior to the rupture of fetal membranes in approximately a third of cases (0% vs. 27%, P = 0.026) and persisted following membrane rupture (31%, P = 0.005). Vaginal dysbiosis was exacerbated by erythromycin treatment (47%, P = 0.00009) particularly in women initially colonised by Lactobacillus spp. Lactobacillus depletion and increased relative abundance of Sneathia spp. were associated with subsequent funisitis and early onset neonatal sepsis. CONCLUSIONS: Our data show that vaginal microbiota composition is a risk factor for subsequent PPROM and is associated with adverse short-term maternal and neonatal outcomes. This highlights vaginal microbiota as a potentially modifiable antenatal risk factor for PPROM and suggests that routine use of erythromycin for PPROM be re-examined.

OBE022, an Oral and Selective Prostaglandin F2α Receptor Antagonist as an Effective and Safe Modality for the Treatment of Preterm Labor.

Preterm birth is the major challenge in obstetrics, affecting ∼10% of pregnancies. Pan-prostaglandin synthesis inhibitors [nonsteroidal anti-inflammatory drugs (NSAIDs)] prevent preterm labor and prolong pregnancy but raise concerns about fetal renal and cardiovascular safety. We conducted preclinical studies examining the tocolytic effect and fetal safety of the oral prodrug candidate OBE022 [(S)-2-amino-3-methyl-butyric acid (S)-3-{[(S)-3-(biphenyl-4-sulfonyl)-thiazolidine-2-carbonyl]-amino}-3-(4-fluoro-phenyl)-propyl ester] and its parent OBE002 [(S)-3-(biphenyl-4-sulfonyl)-thiazolidine-2-carboxylic acid [(S)-1-(4-fluoro-phenyl)-3-hydroxy-propyl]-amide], both potent and highly selective antagonist of the contractile prostaglandin F2α (PGF2α ) receptor (FP). Efficacy of OBE022 and OBE002, alone and in combination with other tocolytics, was assessed in human tissues and pregnant animal models for inhibition of uterine contraction and delay of parturition. Selective safety of OBE022 and/or OBE002, compared with NSAID indomethacin, was assessed on renal function, closure of the ductus arteriosus, and inhibition of platelet aggregation. In in vitro studies, OBE002 inhibited spontaneous, oxytocin- and PGF2α -induced human myometrial contractions alone and was more effective in combination with atosiban or nifedipine. In in vivo studies, OBE022 and OBE002 reduced spontaneous contractions in near-term pregnant rats. In pregnant mice, OBE022 delayed RU486 [(8S,11R,13S,14S,17S)-11-[4-(dimethylamino)phenyl]-17-hydroxy-13-methyl-17-prop-1-ynyl-1,2,6,7,8,11,12,14,15,16-decahydrocyclopenta[a]phenanthren-3-one] -induced parturition and exerted synergistic effects in combination with nifedipine. OBE022 and/or OBE002 did not show the fetal side effects of ductus arteriosus constriction, impairment of kidney function, or inhibition of platelet aggregation observed with indomethacin. Orally active OBE022 and OBE002 exhibits potent tocolytic effects on human tissues ex vivo and animal models in vivo without causing the adverse fetal side effects seen with indomethacin. Selectively targeting the FP receptor in combination with existing tocolytics may be an effective strategy for preventing or delaying preterm delivery.

Differential Effects of Oxytocin Receptor Antagonists, Atosiban and Nolasiban, on Oxytocin Receptor-Mediated Signaling in Human Amnion and Myometrium.

One of the most established roles of oxytocin (OT) is in inducing uterine contractions and labor. Apart from inducing contractions, our recent studies showed that OT can also activate proinflammatory pathways in both human myometrial and amnion cells, which suggests that the proinflammatory role of OT should be taken into account when developing tocolytics targeting the OT/oxytocin receptor (OTR) system. The OTR antagonist, atosiban, is currently used therapeutically for the treatment of preterm labor. We previously showed that atosiban fails to inhibit the proinflammatory effects of OT in human amnion; atosiban alone activates nuclear factor-κB (NF-κB) and mitogen activated protein kinases, thus upregulating downstream prolabor genes. In contrast with our findings with atosiban, the presence of the orally active OTR antagonist, nolasiban, reduced the effect of OT on NF-κB and p38 kinase activation in both myometrial and amnion cells. Consistent with the activation of these inflammatory mediators, OT led to increases in the expression of cyclooxygenase-2 and phosphorylated cytosolic phospholipase A2, which was reflected in prostaglandin E2 synthesis. Inhibition of NF-κB activation by nolasiban also translated to suppression of downstream prolabor gene expression, such as cyclooxygenase-2, C-C motif chemokine ligand 2, interleukin-6, and interleukin-8. We also demonstrated that nolasiban treatment alone has no significant stimulatory effect on both the myometrium and amnion. In conclusion, our findings indicate that nolasiban possesses promising potential as a novel tocolytic agent for both acute and maintenance therapy, as it inhibits both myometrial contractions and the proinflammatory effects of OT without the biased agonist effects.

Specific inhibition of c-Jun N-terminal kinase delays preterm labour and reduces mortality.

Preterm labour (PTL) is commonly associated with infection and/or inflammation. Lipopolysaccharide (LPS) from different bacteria can be used to independently or mutually activate Jun N-terminal kinase (JNK)/AP1- or NF-κB-driven inflammatory pathways that lead to PTL. Previous studies using Salmonella abortus LPS, which activates both JNK/AP-1 and NF-κB, showed that selective inhibition of NF-κB delays labour and improves pup outcome. Where labour is induced using Escherichia coli LPS (O111), which upregulates JNK/AP-1 but not NF-κB, inhibition of JNK/AP-1 activation also delays labour. In this study, to determine the potential role of JNK as a therapeutic target in PTL, we investigated the specific contribution of JNK signalling to S. Abortus LPS-induced PTL in mice. Intrauterine administration of S. Abortus LPS to pregnant mice resulted in the activation of JNK in the maternal uterus and fetal brain, upregulation of pro-inflammatory proteins COX-2, CXCL1, and CCL2, phosphorylation of cPLA2 in myometrium, and induction of PTL. Specific inhibition of JNK by co-administration of specific D-JNK inhibitory peptide (D-JNKI) delayed LPS-induced preterm delivery and reduced fetal mortality. This is associated with inhibition of myometrial cPLA2 phosphorylation and proinflammatory proteins synthesis. In addition, we report that D-JNKI inhibits the activation of JNK/JNK3 and caspase-3, which are important mediators of neural cell death in the neonatal brain. Our data demonstrate that specific inhibition of TLR4-activated JNK signalling pathways has potential as a therapeutic approach in the management of infection/inflammation-associated PTL and prevention of the associated detrimental effects to the neonatal brain.

Exogenous oxytocin modulates human myometrial microRNAs.

OBJECTIVE: MicroRNAs (miRNAs) play a modulatory role in pathways that lead to labor onset, although oxytocin is known to modulate gene expression within the myometrium. We aimed to identify miRNAs whose expression is regulated by oxytocin in pregnant human myometrium. STUDY DESIGN: Myometrial miRNA expression profiles were compared between samples collected from women at term before the onset of labor (no labor; n = 8) and after labor onset after early exogenous oxytocin treatment (n = 8). Multivariate modelling was used to assess differences in miRNA profiles. Biologic validation was undertaken on 3 independent patient cohorts (no labor, n = 10; labor induced with oxytocin, n = 8; and spontaneous labor with no oxytocin treatment, n = 10). In vitro studies that used primary myocytes were undertaken to assess target miRNA expression after oxytocin treatment. Target genes of candidate miRNAs were identified in silico and cross-referenced with genes that are known to be associated with labor or expressed in myometrium. RESULTS: In total, 1309 miRNAs were analyzed by microarray, of which 494 were detected in human myometrium. Multivariate modeling identified 12 target miRNAs the differential expression of which was most responsible for the observed separation of the 2 patient populations in the primary discovery cohorts. Biologic validation in the independent secondary sample cohorts showed that oxytocin independently regulated 5 miRNAs (hsa-miR-146b-3p, hsa-miR-196b-3p, hsa-miR-223-3p, hsa-miR-873-5p, and hsa-miR-876-5p). Additionally, hsa-miR-146b-3p was increased both in labor that was induced with oxytocin and in myometrium from spontaneous labor with no oxytocin treatment compared with no labor samples. Four of the validated miRNAs (hsa-miR-146a-5p, hsa-miR-146b-3p, hsa-miR-196b-3p, and hsa-miR-876-5p) were expressed in primary human myocytes; oxytocin treatment of these cells replicated the directional changes that were observed in vivo. CONCLUSION: Oxytocin alters the expression of a unique set of myometrial miRNAs. These results suggest a further role for oxytocin as a signaling molecule that is involved in the regulation of gene expression during parturition.

Constitutive internalisation of EP2 differentially regulates G protein signalling.

The prostanoid G protein-coupled receptor (GPCR) EP2 is widely expressed and implicated in endometriosis, osteoporosis, obesity, pre-term labour and cancer. Internalisation and intracellular trafficking are critical for shaping GPCR activity, yet little is known regarding the spatial programming of EP2 signalling and whether this can be exploited pharmacologically. Using three EP2-selective ligands that favour activation of different EP2 pathways, we show that EP2 undergoes limited agonist-driven internalisation but is constitutively internalised via dynamin-dependent, ß-arrestin-independent pathways. EP2 was constitutively trafficked to early and very early endosomes (VEE), which was not altered by ligand activation. APPL1, a key adaptor and regulatory protein of the VEE, did not impact EP2 agonist-mediated cAMP. Internalisation was required for ~70% of the acute butaprost- and AH13205-mediated cAMP signalling, yet PGN9856i, a Gαs-biased agonist, was less dependent on receptor internalisation for its cAMP signalling, particularly in human term pregnant myometrial cells that endogenously express EP2. Inhibition of EP2 internalisation partially reduced calcium signalling activated by butaprost or AH13205 and had no effect on PGE2 secretion. This indicates an agonist-dependent differential spatial requirement for Gαs and Gαq/11 signalling and a role for plasma membrane-initiated Gαq/11-Ca2+-mediated PGE2 secretion. These findings reveal a key role for EP2 constitutive internalisation in its signalling and potential spatial bias in mediating its downstream functions. This, in turn, could highlight important considerations for future selective targeting of EP2 signalling pathways.

Prostaglandin F2α requires activation of calcium-dependent signalling to trigger inflammation in human myometrium.

Introduction: Preterm birth is one of the major causes of neonatal morbidity and mortality across the world. Both term and preterm labour are preceded by inflammatory activation in uterine tissues. This includes increased leukocyte infiltration, and subsequent increase in chemokine and cytokine levels, activation of pro-inflammatory transcription factors as NF-κB and increased prostaglandin synthesis. Prostaglandin F2α (PGF2α) is one of the myometrial activators and stimulators. Methods: Here we investigated the role of PGF2α in pro-inflammatory signalling pathways in human myometrial cells isolated from term non-labouring uterine tissue. Primary myometrial cells were treated with G protein inhibitors, calcium chelators and/or PGF2α. Nuclear extracts were analysed by TranSignal cAMP/Calcium Protein/DNA Array. Whole cell protein lysates were analysed by Western blotting. mRNA levels of target genes were analysed by RT-PCR. Results: The results show that PGF2α increases inflammation in myometrial cells through increased activation of NF-κB and MAP kinases and increased expression of COX-2. PGF2α was found to activate several calcium/cAMP-dependent transcription factors, such as CREB and C/EBP-ß. mRNA levels of NF-κB-regulated cytokines and chemokines were also elevated with PGF2α stimulation. We have shown that the increase in PGF2α-mediated COX-2 expression in myometrial cells requires coupling of the FP receptor to both Gαq and Gαi proteins. Additionally, PGF2α-induced calcium response was also mediated through Gαq and Gαi coupling. Discussion: In summary, our findings suggest that PGF2α-induced inflammation in myometrial cells involves activation of several transcription factors - NF-κB, MAP kinases, CREB and C/EBP-ß. Our results indicate that the FP receptor signals via Gαq and Gαi coupling in myometrium. This work provides insight into PGF2α pro-inflammatory signalling in term myometrium prior to the onset of labour and suggests that PGF2α signalling pathways could be a potential target for management of preterm labour.

Interactions between inflammatory signals and the progesterone receptor in regulating gene expression in pregnant human uterine myocytes.

The absence of a fall in circulating progesterone levels has led to the concept that human labour is associated with 'functional progesterone withdrawal' caused through changes in the expression or function of progesterone receptor (PR). At the time of labour, the human uterus is heavily infiltrated with inflammatory cells, which release cytokines to create a 'myometrial inflammation' via NF-κB activation. The negative interaction between NF-κB and PR, may represent a mechanism to account for 'functional progesterone withdrawal' at term. Conversely, PR may act to inhibit NF-κB function and so play a role in inhibition of myometrial inflammation during pregnancy. To model this inter-relationship, we have used small interfering (si) RNA-mediated knock-down of PR in human pregnant myocytes and whole genome microarray analysis to identify genes regulated through PR. We then activated myometrial inflammation using IL-1ß stimulation to determine the role of PR in myometrial inflammation regulation. Through PR-knock-down, we found that PR regulates gene networks involved in myometrial quiescence and extracellular matrix integrity. Activation of myometrial inflammation was found to antagonize PR-induced gene expression, of genes normally upregulated via PR. We found that PR does not play a role in repression of pro-inflammatory gene networks induced by IL-1ß and that only MMP10 was significantly regulated in opposite directions by IL-1ß and PR. We conclude that progesterone acting through PR does not generally inhibit myometrial inflammation. Activation of myometrial inflammation does cause 'functional progesterone withdrawal' but only in the context of genes normally upregulated via PR.

NFκB and AP-1 drive human myometrial IL8 expression.

The uterine expression of the chemokine IL8 increases dramatically with the onset of labour both at term and preterm. The IL8 promoter contains binding sites for the transcription factors nuclear factor-kappa B (NFκB), activator protein-1 (AP-1), and CCAAT/enhancer-binding protein (CEBP). In this study we investigated the roles of these transcription factors in IL1B regulation of the IL8 gene in human myometrium. Using chromatin immune precipitation (ChIP) assay, we showed that each of NFκB, CEBP, and AP-1 binds to the IL8 promoter upon IL1B stimulation. To examine the relative importance of each site in IL8 gene expression, site-directed mutagenesis of each of these sites was performed. We found that the NFκB site was essential for basal and IL1B-stimulated gene expression. Mutation of the AP-1 site reduced both basal and IL1B-stimulated expression but to a lesser extent. Mutation of the CEBP site had no effect upon basal expression but eliminated the IL1B response. Small interfering RNA (siRNA) silencing of NFκB abolished the IL8 response to IL1B significantly; siRNA against AP-1 reduced it to a lesser extent whilst knockdown of CEBP enhanced the response. Our data confirms a central and essential role for NFκB in regulation of IL8 in human myometrium.

Functional rewiring of G protein-coupled receptor signaling in human labor.

Current strategies to manage preterm labor center around inhibition of uterine myometrial contractions, yet do not improve neonatal outcomes as they do not address activation of inflammation. Here, we identify that during human labor, activated oxytocin receptor (OTR) reprograms the prostaglandin E2 receptor, EP2, in the pregnant myometrium to suppress relaxatory/Gαs-cAMP signaling and promote pro-labor/inflammatory responses via altered coupling of EP2 from Gαq/11 to Gαi/o. The ability of EP2 to signal via Gαi/o is recapitulated with in vitro OT and only following OTR activation, suggesting direct EP2-OTR crosstalk. Super-resolution imaging with computational modeling reveals OT-dependent reorganization of EP2-OTR complexes to favor conformations for Gαi over Gαs activation. A selective EP2 ligand, PGN9856i, activates the relaxatory/Gαs-cAMP pathway but not the pro-labor/inflammatory responses in term-pregnant myometrium, even following OT. Our study reveals a mechanism, and provides a potential therapeutic solution, whereby EP2-OTR functional associations could be exploited to delay preterm labor.

Microbial-driven preterm labour involves crosstalk between the innate and adaptive immune response.

There has been a surge in studies implicating a role of vaginal microbiota in spontaneous preterm birth (sPTB), but most are associative without mechanistic insight. Here we show a comprehensive approach to understand the causative factors of preterm birth, based on the integration of longitudinal vaginal microbiota and cervicovaginal fluid (CVF) immunophenotype data collected from 133 women at high-risk of sPTB. We show that vaginal depletion of Lactobacillus species and high bacterial diversity leads to increased mannose binding lectin (MBL), IgM, IgG, C3b, C5, IL-8, IL-6 and IL-1ß and to increased risk of sPTB. Cervical shortening, which often precedes preterm birth, is associated with Lactobacillus iners and elevated levels of IgM, C3b, C5, C5a and IL-6. These data demonstrate a role for the complement system in microbial-driven sPTB and provide a scientific rationale for the development of live biotherapeutics and complement therapeutics to prevent sPTB.

NF-κB regulates a cassette of immune/inflammatory genes in human pregnant myometrium at term.

The onset of human labour resembles inflammation with increased synthesis of prostaglandins and cytokines. There is evidence from rodent models for an important role for nuclear factor-κB (NF-κB) activity in myometrium which both up-regulates contraction-associated proteins and antagonizes the relaxatory effects of progesterone. Here we show that in the human, although there are no differences in expression of NF-κB p65, or IκB-α between upper- or lower-segment myometrium or before or after labour, there is nuclear localization of serine-256-phospho-p65 and serine-536-phospho-p65 in both upper- and lower-segment myometrium both before and after the onset of labour at term. This shows that NF-κB is active in both upper and lower segment prior to the onset of labour at term. To identify the range of genes regulated by NF-κB we overexpressed p65 in myocytes in culture. This led to NF-κB activation identical to that seen following interleukin (IL)-1ß stimulation, including phosphorylation and nuclear translocation of p65 and p50. cDNA microarray analysis showed that NF-κB increased expression of 38 genes principally related to immunity and inflammation. IL-1ß stimulation also resulted in an increase in the expression of the same genes. Transfection with siRNA against p65 abolished the response to IL-1ß proving a central role for NF-κB. We conclude that NF-κB is active in myocytes in both the upper and lower segment of the uterus prior to the onset of labour at term and principally regulates a group of immune/inflammation associated genes, demonstrating that myocytes can act as immune as well as contractile cells.

Labor and inflammation increase the expression of oxytocin receptor in human amnion.

The oxytocin/oxytocin receptor (OXT/OXTR) system plays an important role in the regulation of parturition. The amnion is a major source of prostaglandins and inflammatory cytokine synthesis, which increase both before and during labor. Amnion is a noncontractile tissue; therefore, the role played by OXT/OXTR in this tissue will be fundamentally different from the role played in myometrial contractions. In the present study, we demonstrate increased OXTR mRNA and protein concentrations in human amnion epithelial cells associated with the onset of labor. We show that incubation of primary human amnion epithelial cells with IL1B results in a rapid, transient up-regulation of OXTR mRNA expression, which peaks in prelabor samples after 6 h. Incubation of prelabor amnion epithelial cells with OXT results in a marked increase of prostaglandin E(2) synthesis, and we demonstrate that OXT activates the extracellular signal-regulated protein kinase signal transduction pathway to stimulate up-regulation of cyclo-oxygenase 2 in human amnion epithelial cells. The increased ability of human amnion to produce prostaglandins in response to OXT treatment suggests a complementary role for the OXT/OXTR system in the activation of human amnion and the onset of labor.

Synergistic regulation of human oxytocin receptor promoter by CCAAT/ enhancer-binding protein and RELA.

Uterine activation is associated with increased oxytocin receptor (OXTR) expression and myometrial sensitivity to oxytocin. The OXTR promoter contains binding sites for CCAAT/enhancer-binding protein (CEBP) and nuclear factor-kappa B p65 (RELA). RELA and CEBP beta (CEBPB) play a synergistic role in OXTR promoter activation. We created deletions in a DNA construct consisting of 850 bp upstream of the transcription start site linked to luc reporter to identify the CIS element of the OXTR promoter responsible for the synergistic activation by RELA and CEBPB. Deletion from -712 to -692 bp eliminated synergy, demonstrating that the critical region lies within these 20 bp. Binding studies showed that this sequence binds both RELA and CEBPB. The 20-bp critical region for synergistic activation of OXTR requires full-length RELA but only the basic leucine zipper domain of CEBPB.

Whole Blood Holding Time Prior to Plasma Processing Alters microRNA Expression Profile.

MicroRNAs (miRNAs) can exhibit aberrant expression under different physiological and pathological conditions. Therefore, differentially expressed circulating miRNAs have been a focus of biomarker discovery research. However, the use of circulating miRNAs comes with challenges which may hinder the reliability for their clinical application. These include varied sample collection protocols, storage times/conditions, sample processing and analysis methods. This study focused on examining the effect of whole blood holding time on the stability of plasma miRNA expression profiles. Whole blood samples were collected from healthy pregnant women and were held at 4°C for 30 min, 2 h, 6 h or 24 h prior to processing for plasma isolation. Plasma RNA was extracted and the expression of 179 miRNAs were analyzed. Unsupervised principal component analysis demonstrated that whole blood holding time was a major source of variation in miRNA expression profiles with 53 of 179 miRNAs showing significant changes in expression. Levels of specific miRNAs previously reported to be associated with pregnancy-associated complications such as hsa-miR-150-5p, hsa-miR-191-5p, and hsa-miR-29a-3p, as well as commonly used endogenous miRNA controls, hsa-miR-16-5p, hsa-miR-25-3p, and hsa-miR-223-3p were significantly altered with increase in blood holding time. Current protocols for plasma-based miRNA profiling for diagnostics describe major differences in whole blood holding periods ranging from immediately after collection to 26 h after. Our results demonstrate holding time can have dramatic effects on analytical reliability and reproducibility. This highlights the importance of standardization of blood holding time prior to processing for plasma in order to minimize introduction of non-biological variance in miRNA profiles.

Direct on-swab metabolic profiling of vaginal microbiome host interactions during pregnancy and preterm birth.

The pregnancy vaginal microbiome contributes to risk of preterm birth, the primary cause of death in children under 5 years of age. Here we describe direct on-swab metabolic profiling by Desorption Electrospray Ionization Mass Spectrometry (DESI-MS) for sample preparation-free characterisation of the cervicovaginal metabolome in two independent pregnancy cohorts (VMET, n = 160; 455 swabs; VMET II, n = 205; 573 swabs). By integrating metataxonomics and immune profiling data from matched samples, we show that specific metabolome signatures can be used to robustly predict simultaneously both the composition of the vaginal microbiome and host inflammatory status. In these patients, vaginal microbiota instability and innate immune activation, as predicted using DESI-MS, associated with preterm birth, including in women receiving cervical cerclage for preterm birth prevention. These findings highlight direct on-swab metabolic profiling by DESI-MS as an innovative approach for preterm birth risk stratification through rapid assessment of vaginal microbiota-host dynamics.