Forkhead box O1 (FOXO1) in pregnant human myometrial cells: a role as a pro-inflammatory mediator in human parturition

Maternal serum interleukin-1β, FoxO1 and Sestrin2 levels in predicting preterm delivery

The study aimed to investigate whether serum IL-1β, FoxO1and Sesn2 concentrations differed between threatened preterm labor (TPL) and uncomplicated pregnancies. This study was conducted on 54 women with TPL pregnancies and 26 healthy pregnant women. The TPL group was further divided into two subgroups according to the gestational age at delivery. Patients who gave birth within 48-72 hours after the hospitalization were referred to as preterm delivery (PD) and those who gave birth at ≥37 weeks were referred to as term delivery (TD). Maternal levels of serum IL-1β, FoxO1 and Sesn2 were measured with the use of enzyme-linked immunosorbent assay kits. The mean maternal serum IL-1β and FoxO1 of PD were significantly higher than TD (p<.000*) and the control group (p < .000*). The mean maternal serum IL-1β, FoxO1 level of TD was significantly higher than the control group (p<.000*). The mean maternal serum Sesn2 levels of TD and the control group were significantly higher than the preterm group (p<.000*). The mean maternal serum Sesn2 level of the control group was significantly higher than the TD group (p <.000*). A negative correlation was found between serum concentration of serum IL-1β, and FoxO1 with the gestational week of delivery (r= -0.722, p< .000*for, IL-1β; r = -0.625, p < .000* for FoxO1). A positive correlation was found between the serum concentration of serum Sesn2 with the gestational week of delivery (r = 0.507, p<.000* for sesn2). High serum IL-1β, FoxO1 levels, and low Sesn2 levels may have the potential to be used as biomarkers for the differentiation of PD and TD.

Reepithelialization of Diabetic Skin and Mucosal Wounds Is Rescued by Treatment With Epigenetic Inhibitors

Wound healing is a complex, highly regulated process and is substantially disrupted by diabetes. We show here that human wound healing induces specific epigenetic changes that are exacerbated by diabetes in an animal model. We identified epigenetic changes and gene expression alterations that significantly reduce reepithelialization of skin and mucosal wounds in an in vivo model of diabetes, which were dramatically rescued in vivo by blocking these changes. We demonstrate that high glucose altered FOXO1-matrix metallopeptidase 9 (MMP9) promoter interactions through increased demethylation and reduced methylation of DNA at FOXO1 binding sites and also by promoting permissive histone-3 methylation. Mechanistically, high glucose promotes interaction between FOXO1 and RNA polymerase-II (Pol-II) to produce high expression of MMP9 that limits keratinocyte migration. The negative impact of diabetes on reepithelialization in vivo was blocked by specific DNA demethylase inhibitors in vivo and by blocking permissive histone-3 methylation, which rescues FOXO1-impaired keratinocyte migration. These studies point to novel treatment strategies for delayed wound healing in individuals with diabetes. They also indicate that FOXO1 activity can be altered by diabetes through epigenetic changes that may explain other diabetic complications linked to changes in diabetes-altered FOXO1-DNA interactions.

ARTICLE HIGHLIGHTS

FOXO1 expression in keratinocytes is needed for normal wound healing. In contrast, FOXO1 expression interferes with the closure of diabetic wounds. Using matrix metallopeptidase 9 as a model system, we found that high glucose significantly increased FOXO1-matrix metallopeptidase 9 interactions via increased DNA demethylation, reduced DNA methylation, and increased permissive histone-3 methylation in vitro. Inhibitors of DNA demethylation and permissive histone-3 methylation improved the migration of keratinocytes exposed to high glucose in vitro and the closure of diabetic skin and mucosal wounds in vivo. Inhibition of epigenetic enzymes that alter FOXO1-induced gene expression dramatically improves diabetic healing and may apply to other conditions where FOXO1 has a detrimental role in diabetic complications.

Progesterone control of myometrial contractility

During pregnancy, the primary function of the uterus is to be quiescent and not contract, which allows the growing fetus to develop and mature. A uterine muscle layer, myometrium, is composed of smooth muscle cells (SMCs). Before the onset of labor contractions, the uterine SMCs experience a complex biochemical and molecular transformation involving the expression of contraction-associated proteins. Labor is initiated when genes in SMCs are activated in response to a combination of hormonal, inflammatory and mechanical signals. In this review, we provide an overview of molecular mechanisms regulating the process of parturition in humans, focusing on the hormonal control of the myometrium, particularly the steroid hormone progesterone. The primary reason for discussing the regulation of myometrial contractility by progesterone is the importance of the clinical problem of preterm birth. It is thought that the hormonal mechanisms regulating premature uterine contractions represent an untimely triggering of the normal events occurring during term parturition. Yet, our knowledge of the complex and redundant hormonal pathways controlling uterine contractile activity leading to delivery of the neonate remains incomplete. Finally, we introduce recent animal studies using a novel class of drugs, Selective Progesterone Receptor Modulators, targeting progesterone signaling to prevent premature myometrial contractions.

Effect of FoxO1 on Cardiomyocyte Apoptosis and Inflammation in Viral Myocarditis via Modultion of the TLR4/NF-κB Signaling Pathway

To investigate the possible effect of FoxO on coxsackievirus B3 (CVB3) -induced cardiomyocyte inflammation and apoptosis via modulation of the TLR4/NF-κB signaling pathway.Viral myocarditis (VMC) models were establied via CVB3 infection both in vivo and in vitro. Western blotting was adopted to detect FoxO1 and TLR4 expressions in myocardial tissues and cells. Cardiomyocytes of suckling mouse were divided into the control, CVB3, CVB3 + pcDNA, CVB3 + pcDNA-FoxO1, CVB3 + TLR4 siRNA, and CVB3 + pcDNA-FoxO1 + TLR4 siRNA groups. Flow cytometry was employed to evaluate cell apoptosis. The expressions of inflammatory factors including TNF-α, IL-1β, and IL-6 were detected via quantitative reverse transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay. Then, TLR4/NF-κB pathway-related proteins were determined via Western blotting.VMC mice had increased FoxO1 and TLR4 expressions in myocardial tissues. Cardiomyocytes with CVB3 infection also had upregulated protein expressions of p-FoxO1/FoxO1 and TLR4. Compared with those in the control group, the cardiomyocytes in the CVB3 group were increased in LDH and CK-MB levels, cell apoptosis rate and inflammatory factors (TNF-α, IL-1β and IL-6), as well as protein expressions of TLR4 and p-p65/p65. Compared with those in the CVB3 group, the cardiomyocytes in the CVB3 + pcDNA-FoxO1 group were further upregulated whereas those in the CVB3 +TLR4 siRNA group were downregulated in the aforementioned indicators. Furthermore, TLR4 siRNA can reverse the effect of pcDNA-FoxO1 on the aggravation of cardiomyocyte injury induced by CVB3 infection.FoxO1 can upregulate the TLR4/NF-κB signaling pathway to promote cardiomyocyte apoptosis and inflammatory injury in CVB3-induced VMC.

Propofol alleviates postoperative cognitive dysfunction by inhibiting inflammation via up-regulating miR-223-3p in aged rats

OBJECTIVE

Postoperative cognitive dysfunction (POCD) affects 15-25% of surgical patients and causes significant morbidity and mortality. This study aims to investigate the mechanism of propofol reducing POCD in aged rats.

METHOD

Rats in Operate group and Propofol group were anesthetized with isoflurane and propofol, respectively, and then underwent cardiac surgery. Rats in Antagomir group were anesthetized with propofol and underwent cardiac surgery with preoperative injection of miR-223-3p antagomir. Barnes maze and Morris water maze (MWM) were used to test spatial learning and memory of rats. Immunofluorescence was used to detect the level of microglial cell marker IBA1. In addition, qRT-PCR was performed to measure the expression of miR-223-3p and inflammatory factors TNF-α, IL-1β and IL-6. Western blotting was conducted to detect the protein expression of Foxo1, TNF-α, IL-1β and IL-6.

RESULT

Isoflurane-anesthetized rats undergoing cardiac surgery showed significantly reduced spatial learning and memory, promoted microglia activation, decreased miR-223-3p expression and increased inflammatory response in the hippocampus, while isoflurane-anesthetized rats without surgery showed insignificant changes in these indices. Compared to isoflurane anesthesia, propofol anesthesia exhibited less effect on spatial learning and memory of rats with cardiac surgery and contributed to a relative reduction in activated microglia in the hippocampus, a notable increase in miR-223-3p expression, and a decrease in inflammation. The results were reversed after miR-223-3p antagomir was injected into propofol-anesthetized surgical rats. miR-223-3p negatively regulated Foxo1 to suppress the expression of inflammatory factors.

CONCLUSION

Propofol reduced inflammation by up-regulating miR-223-3p, thereby reducing POCD in aged rats.

Forkhead Box 1(FoxO1) mediates psychological stress-induced neuroinflammation

OBJECTIVES

 Neuroinflammation plays a key role in cerebrovascular disease (CVD). Neuropsychiatric disorders appear to share an epidemiological association with inflammation, but the mechanisms are unclear. Forkhead box 1 (FoxO1) regulates inflammatory signaling in diabetes and cardiovascular diseases, but its role in psychological stress-induced neuroinflammation remains unknown. Therefore, we investigated the potential involvement of FoxO1 in repeated social defeat stress (RSDS)-induced neuroinflammation.

METHODS

 6-week-old male C57BL/6 J mice were randomly divided into RSDS or control groups. In the RSDS group, mice (18-22 g) were individually subjected to social defeat by an 8-week-old CD-1 mouse (28-32 g) for 10 min daily for 10 consecutive days. At 24 h after this 10-day process, corticosterone (CORT), epinephrine (EPI), hydrogen peroxide, and inflammatory factors (TNF-α, IL-6, IL-1β, and VCAM-1) from serum and brain tissues were assayed using ELISA, real-time PCR, and Western blot. Iba-1 was determined by immunofluorescence (IF), and FoxO1 siRNA was transfected into BV2 cells to further analyze the expression of inflammatory factors.

RESULTS

RSDS significantly increased the levels of TNF-α, IL-6, IL-1β, and VCAM-1 in the serum; it also increased both mRNA and protein expression of these in the brain. FoxO1 was significantly increased after stress, while its knockdown significantly suppressed stress-induced inflammation. Immunofluorescence demonstrated the activation of microglia in the setting of RSDS.

CONCLUSION

RSDS induced a measurable inflammatory response in the blood and brain, and FoxO1 was demonstrated in vitro to aggravate stress-induced inflammation.

TBX2, a Novel Regulator of Labour

Background and Objectives: Therapeutic interventions targeting molecular factors involved in the transition from uterine quiescence to overt labour are not substantially reducing the rate of spontaneous preterm labour. The identification of novel rational therapeutic targets are essential to prevent the most common cause of neonatal mortality. Based on our previous work showing that Tbx2 (T-Box transcription factor 2) is a putative upstream regulator preceding progesterone withdrawal in mouse myometrium, we now investigate the role of TBX2 in human myometrium. Materials and Methods: RNA microarray analysis of (A) preterm human myometrium samples and (B) myometrial cells overexpressing TBX2 in vitro, combined with subsequent analysis of the two publicly available datasets of (C) Chan et al. and (D) Sharp et al. The effect of TBX2 overexpression on cytokines/chemokines secreted to the myometrium cell culture medium were determined by Luminex assay. Results: Analysis shows that overexpression of TBX2 in myometrial cells results in downregulation of TNFα- and interferon signalling. This downregulation is consistent with the decreased expression of cytokines and chemokines of which a subset has been previously associated with the inflammatory pathways relevant for human labour. In contrast, CXCL5 (C-X-C motif chemokine ligand 5), CCL21 and IL-6 (Interleukin 6), previously reported in relation to parturition, do not seem to be under TBX2 control. The combined bioinformatical analysis of the four mRNA datasets identifies a subset of upstream regulators common to both preterm and term labour under control of TBX2. Surprisingly, TBX2 mRNA levels are increased in preterm contractile myometrium. Conclusions: We identified a subset of upstream regulators common to both preterm and term labour that are activated in labour and repressed by TBX2. The increased TBX2 mRNA expression in myometrium collected during a preterm caesarean section while in spontaneous preterm labour compared to tissue harvested during iatrogenic preterm delivery does not fit the bioinformatical model. We can only explain this by speculating that the in vivo activity of TBX2 in human myometrium depends not only on the TBX2 expression levels but also on levels of the accessory proteins necessary for TBX2 activity.

Transcriptional control of parturition: insights from gene regulation studies in the myometrium

The onset of labour is a culmination of a series of highly coordinated and preparatory physiological events that take place throughout the gestational period. In order to produce the associated contractions needed for foetal delivery, smooth muscle cells in the muscular layer of the uterus (i.e. myometrium) undergo a transition from quiescent to contractile phenotypes. Here, we present the current understanding of the roles transcription factors play in critical labour-associated gene expression changes as part of the molecular mechanistic basis for this transition. Consideration is given to both transcription factors that have been well-studied in a myometrial context, i.e. activator protein 1, progesterone receptors, oestrogen receptors, and nuclear factor kappa B, as well as additional transcription factors whose gestational event-driving contributions have been demonstrated more recently. These transcription factors may form pregnancy- and labour-associated transcriptional regulatory networks in the myometrium to modulate the timing of labour onset. A more thorough understanding of the transcription factor-mediated, labour-promoting regulatory pathways holds promise for the development of new therapeutic treatments that can be used for the prevention of preterm labour in at-risk women.

Using ESTIMATE algorithm to establish an 8-mRNA signature prognosis prediction system and identify immunocyte infiltration-related genes in Pancreatic adenocarcinoma

OBJECTIVE

The tumour microenvironment is one of the significant factors driving the carcinogenesis of Pancreatic adenocarcinoma (PAAD). However, the underlying mechanism of how the tumour microenvironment impacts the prognosis of PAAD is not completely clear.

RESULTS

The transcriptome and clinical data of 182 PAAD program cases were downloaded from the TCGA database. Three hundred thirty-three differentially expressed genes (DEGs) between high and low stromal groups and 314 DEGs between high and low immune score groups were identified using ESTIMATE score. Based on the 203 genes differentially expressed simultaneously in two score-related comparisons, we established an 8-mRNA signature to evaluate the prognosis of PAAD patients. Kaplan-Meier curves showed significantly worse survival for patients with high-risk scores in both the training and validation groups. The risk score was an independent prognostic factor and had a high predictive value for the prognosis of patients with PAAD. By searching the TCGA database, we showed that CA9, CXCL9, and GIMAP7 from the 8-mRNA signature were associated with the infiltration levels of immunocytes by regulating FOXO1 expression in PAAD.

CONCLUSIONS

Unlike traditional methods of screening for differential genes in cancer and healthy tissues, we constructed a novel 8-mRNA signature to predict the prognosis of PAAD patients by applying ESTIMATE scoring to RNA-seq-based transcriptome data. Most importantly, we identified CA9, CXCL9, and GIMAP7 from the above eight genes as regulators of immunocyte infiltration by adjusting the expression of FOXO1 in PAAD. Thus, CA9, CXCL9, and GIMAP7 might be the ideal targets of immune therapy of PAAD.

METHODS

ESTIMATE scoring was used to determine the stromal and immune scores of transcriptome datasets downloaded from the TCGA database. An mRNA-based prognostic signature was built for the training cohort via the LASSO Cox regression model. The signature was verified using a validation cohort. Kaplan-Meier curves and log-rank analysis were used to identify survival differences. Western blot analysis and RT-qPCR analysis were carried out to analyze the expression of specific proteins and mRNAs. IHC was performed to assess the protein levels of Forkhead box-O 1 (FOXO1), Carbonic anhydrase 9 (CA9), C-X-C motif chemokine ligand 9 (CXCL9), and GTPase, IMAP family member 7 (GIMAP7) in the tissue microarray of PAAD.

Lysophosphatidylcholine induces cyclooxygenase-2-dependent IL-6 expression in human cardiac fibroblasts

Lysophosphatidylcholine (LysoPC) has been shown to induce the expression of inflammatory proteins, including cyclooxygenase-2 (COX-2) and interleukin-6 (IL-6), associated with cardiac fibrosis. Here, we demonstrated that LysoPC-induced COX-2 and IL-6 expression was inhibited by silencing NADPH oxidase 1, 2, 4, 5; p65; and FoxO1 in human cardiac fibroblasts (HCFs). LysoPC-induced IL-6 expression was attenuated by a COX-2 inhibitor. LysoPC-induced responses were mediated via the NADPH oxidase-derived reactive oxygen species-dependent JNK1/2 phosphorylation pathway, leading to NF-κB and FoxO1 activation. In addition, we demonstrated that both FoxO1 and p65 regulated COX-2 promoter activity stimulated by LysoPC. Overexpression of wild-type FoxO1 and S256D FoxO1 enhanced COX-2 promoter activity and protein expression in HCFs. These results were confirmed by ex vivo studies, where LysoPC-induced COX-2 and IL-6 expression was attenuated by the inhibitors of NADPH oxidase, NF-κB, and FoxO1. Our findings demonstrate that LysoPC-induced COX-2 expression is mediated via NADPH oxidase-derived reactive oxygen species generation linked to the JNK1/2-dependent pathway leading to FoxO1 and NF-κB activation in HCFs. LysoPC-induced COX-2-dependent IL-6 expression provided novel insights into the therapeutic targets of the cardiac fibrotic responses.

FOXO1 deletion in keratinocytes improves diabetic wound healing through MMP9 regulation

Keratinocyte migration is a key aspect of re-epithelialization during wound healing. Matrix metalloproteinase 9 (MMP9) contributes to this process and deficiencies in the MMP9 lead to impaired healing. Inappropriate expression of MMP9 also contributes to impaired re-epithelialization. Previously we demonstrated that FOXO1 was activated in wound healing but to higher levels in diabetic wounds. To address mechanisms of impaired re-epithelialization we examined MMP9 expression in vivo in full thickness dermal scalp wounds created in experimental K14.Cre⁺.Foxo1^L/L mice with lineage-specific Cre recombinase deletion of floxed FOXO1 and compared the results to control littermates. MMP9 was induced during wound healing but at a significantly higher level in diabetic compared to normal wounds. FOXO1 deletion substantially blocked this increase. By chromatin immunoprecipitation FOXO1 was shown to bind to the MMP9 promoter, FOXO1 overexpression increased MMP9 transcriptional activity and increased MMP9 expression stimulated by high glucose was blocked by FOXO1 deletion or FOXO1 knockdown. We also show for the first time that high glucose impairs keratinocyte migration by inducing high levels of MMP9 expression and establish that it involves FOXO1. Thus, FOXO1 drives high levels of MMP9 expression in diabetic wound healing, which represents a novel mechanism for impaired re-epithelization in diabetic wounds.

Characteristic Changes in Decidual Gene Expression Signature in Spontaneous Term Parturition

Background

The decidua has been implicated in the “terminal pathway” of human term parturition, which is characterized by the activation of pro-inflammatory pathways in gestational tissues. However, the transcriptomic changes in the decidua leading to terminal pathway activation have not been systematically explored. This study aimed to compare the decidual expression of developmental signaling and inflammation-related genes before and after spontaneous term labor in order to reveal their involvement in this process.

Methods

Chorioamniotic membranes were obtained from normal pregnant women who delivered at term with spontaneous labor (TIL, n = 14) or without labor (TNL, n = 15). Decidual cells were isolated from snap-frozen chorioamniotic membranes with laser microdissection. The expression of 46 genes involved in decidual development, sex steroid and prostaglandin signaling, as well as pro- and anti-inflammatory pathways, was analyzed using high-throughput quantitative real-time polymerase chain reaction (qRT-PCR). Chorioamniotic membrane sections were immunostained and then semi-quantified for five proteins, and immunoassays for three chemokines were performed on maternal plasma samples.

Results

The genes with the highest expression in the decidua at term gestation included insulin-like growth factor-binding protein 1 (IGFBP1), galectin-1 (LGALS1), and progestogen-associated endometrial protein (PAEP); the expression of estrogen receptor 1 (ESR1), homeobox A11 (HOXA11), interleukin 1β (IL1B), IL8, progesterone receptor membrane component 2 (PGRMC2), and prostaglandin E synthase (PTGES) was higher in TIL than in TNL cases; the expression of chemokine C-C motif ligand 2 (CCL2), CCL5, LGALS1, LGALS3, and PAEP was lower in TIL than in TNL cases; immunostaining confirmed qRT-PCR data for IL-8, CCL2, galectin-1, galectin-3, and PAEP; and no correlations between the decidual gene expression and the maternal plasma protein concentrations of CCL2, CCL5, and IL-8 were found.

Conclusions

Our data suggests that with the initiation of parturition, the decidual expression of anti-inflammatory mediators decreases, while the expression of pro-inflammatory mediators and steroid receptors increases. This shift may affect downstream signaling pathways that can lead to parturition.

Comparing human and macaque placental transcriptomes to disentangle preterm birth pathology from gestational age effects

INTRODUCTION

A major issue in the transcriptomic study of spontaneous preterm birth (sPTB) in humans is the inability to collect healthy control tissue at the same gestational age (GA) to compare with pathologic preterm tissue. Thus, gene expression differences identified after the standard comparison of sPTB and term tissues necessarily reflect differences in both sPTB pathology and GA. One potential solution is to use GA-matched controls from a closely related species to tease apart genes that are dysregulated during sPTB from genes that are expressed differently as a result of GA effects.

METHODS

To disentangle genes whose expression levels are associated with sPTB pathology from those linked to GA, we compared RNA sequencing data from human preterm placentas, human term placentas, and rhesus macaque placentas at 80% completed gestation (serving as healthy non-human primate GA-matched controls). We first compared sPTB and term human placental transcriptomes to identify significantly differentially expressed genes. We then overlaid the results of the comparison between human sPTB and macaque placental transcriptomes to identify sPTB-specific candidates. Finally, we overlaid the results of the comparison between human term and macaque placental transcriptomes to identify GA-specific candidates.

RESULTS

Examination of relative expression for all human genes with macaque orthologs identified 267 candidate genes that were significantly differentially expressed between preterm and term human placentas. 29 genes were identified as sPTB-specific candidates and 37 as GA-specific candidates. Altogether, the 267 differentially expressed genes were significantly enriched for a variety of developmental, metabolic, reproductive, immune, and inflammatory functions. Although there were no notable differences between the functions of the 29 sPTB-specific and 37 GA-specific candidate genes, many of these candidates have been previously shown to be dysregulated in diverse pregnancy-associated pathologies.

DISCUSSION

By comparing human sPTB and term transcriptomes with GA-matched control transcriptomes from a closely related species, this study disentangled the confounding effects of sPTB pathology and GA, leading to the identification of 29 promising sPTB-specific candidate genes and 37 genes potentially related to GA effects. The apparent similarity in functions of the sPTB and GA candidates may suggest that the effects of sPTB and GA do not correspond to biologically distinct processes. Alternatively, it may reflect the poor state of knowledge of the transcriptional landscape underlying placental development and disease.

Roles and regulation of the matrix metalloproteinase system in parturition

Significant tissue destruction, repair, and remodeling are involved in parturition, which involves fetal membrane rupture, cervical ripening, and uterine contraction and its subsequent involution. Extracellular matrix degradation and remodeling by proteolytic enzymes, such as matrix metalloproteinases (MMPs), are required for the final steps of parturition. MMPs participate in physiological degradation and remodeling through their proteolytic activities on specific substrates, and are balanced by the action of their inhibitors. Disruption to this balance can result in pathological stress that ends with preterm or post-term birth or pre-eclampsia. In this review, we examine the roles and regulation of the MMP system in physiological and pathological labor, and propose a model that illustrates the mechanisms by which the MMP system contributes to these processes.

Mevastatin ameliorates sphingosine 1-phosphate-induced COX-2/PGE2-dependent cell migration via FoxO1 and CREB phosphorylation and translocation

BACKGROUND AND PURPOSE

Sphingosine 1-phosphate (S1P), an important inflammatory mediator, has been shown to regulate COX-2 production and promote various cellular responses such as cell migration. Mevastatin, an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA), effectively inhibits inflammatory responses. However, the mechanisms underlying S1P-evoked COX-2-dependent cell migration, which is modulated by mevastatin in human tracheal smooth muscle cells (HTSMCs) remain unclear.

EXPERIMENTAL APPROACH

The expression of COX-2 was determined by Western blotting, real time-PCR and promoter analyses. The signalling molecules were investigated by pretreatment with respective pharmacological inhibitors or transfection with siRNAs. The interaction between COX-2 promoter and transcription factors was determined by chromatin immunoprecipitation assay. Finally, the effect of mevastatin on HTSMC migration and leukocyte counts in BAL fluid and COX-2 expression induced by S1P was determined by a cell migration assay, cell counting and Western blot.

KEY RESULTS

S1P stimulated mTOR activation through the Nox2/ROS and PI3K/Akt pathways, which can further stimulate FoxO1 phosphorylation and translocation to the cytosol. We also found that S1P induced CREB activation and translocation via an mTOR-independent signalling pathway. Finally, we showed that pretreatment with mevastatin markedly reduced S1P-induced cell migration and COX-2/PGE2 production via a PPARγ-dependent signalling pathway.

CONCLUSIONS AND IMPLICATIONS

Mevastatin attenuates the S1P-induced increased expression of COX-2 and cell migration via the regulation of FoxO1 and CREB phosphorylation and translocation by PPARγ in HTSMCs. Mevastatin could be beneficial for prevention of airway inflammation in the future.

Novel Noncompetitive IL-1 Receptor-Biased Ligand Prevents Infection- and Inflammation-Induced Preterm Birth

Preterm birth (PTB) is firmly linked to inflammation regardless of the presence of infection. Proinflammatory cytokines, including IL-1β, are produced in gestational tissues and can locally upregulate uterine activation proteins. Premature activation of the uterus by inflammation may lead to PTB, and IL-1 has been identified as a key inducer of this condition. However, all currently available IL-1 inhibitors are large molecules that exhibit competitive antagonism properties by inhibiting all IL-1R signaling, including transcription factor NF-κB, which conveys important physiological roles. We hereby demonstrate the efficacy of a small noncompetitive (all-d peptide) IL-1R-biased ligand, termed rytvela (labeled 101.10) in delaying IL-1β-, TLR2-, and TLR4-induced PTB in mice. The 101.10 acts without significant inhibition of NF-κB, and instead selectively inhibits IL-1R downstream stress-associated protein kinases/transcription factor c-jun and Rho GTPase/Rho-associated coiled-coil-containing protein kinase signaling pathways. The 101.10 is effective at decreasing proinflammatory and/or prolabor genes in myometrium tissue and circulating leukocytes in all PTB models independently of NF-κB, undermining NF-κB role in preterm labor. In this work, biased signaling modulation of IL-1R by 101.10 uncovers a novel strategy to prevent PTB without inhibiting NF-κB.

Slit2 exerts anti-inflammatory actions in human placenta and is decreased with maternal obesity

PROBLEM

Obese pregnancies are characterised by increased inflammation. Members of the Slit/Roundabout (Robo) family are key regulators of the inflammatory response. The aim of this study was to determine the effect of (i) pre-existing maternal obesity on Slit-Robo expression in human placenta and (ii) Slit2 knockdown by siRNA in primary trophoblast cells on markers of inflammation.

METHOD OF STUDY

The expression of Slit-Robo protiens was assessed in human placenta from lean (n = 15) and obese (n = 16) patients by qRT-PCR and Western blotting. Primary trophoblast cells were used to determine the effect of pro-inflammatory mediators on Slit2 expression, and the effect of Slit2 siRNA on pro-inflammatory mediators.

RESULTS

While there was no change in Slit3, Robo1 or Robo4 expression, Slit2 expression was significantly lower in obese placenta compared to lean placenta. Human primary trophoblast cells treated with pro-inflammatory mediators IL-1β, TNF-α and LPS significantly decreased Slit2 expression. Slit2 silencing by siRNA augmented IL-6 expression and secretion in cells stimulated with TNF-α, LPS and TNF-α; IL-8 gene expression and/or release in cells stimulated with IL-1β and LPS; TNF-α gene expression and secretion in cells stimulated with LPS; and MMP-9 gene expression and pro MMP-9 levels in cells stimulated with TNF-α.

CONCLUSION

The anti-inflammatory effects of Slit2 in human placenta is a novel finding, and suggests that inflammatory mediators, which are increased with obesity, downregulates Slit2 to enhance placental inflammation. Given the central role of pro-inflammatory cytokines in placental nutrient transport, our findings suggest Slit2 may play a role in fetal growth and development.

Slit2 is decreased after spontaneous labour in myometrium and regulates pro-labour mediators

Preterm birth, a global healthcare problem, is commonly associated with inflammation. As Slit2 plays an emerging role in inflammation, the purpose of this study was to determine the effect of Slit2 on labour mediators in human gestational tissues. Slit2 mRNA and protein expression were assessed using qRT-PCR and immunohistochemistry in foetal membranes and myometrium obtained before and after labour. Slit2 silencing was achieved using siRNA in primary myometrial cells. Pro-inflammatory and pro-labour mediators were evaluated by qRT-PCR, ELISA and gelatin zymography. Slit2 mRNA and protein expression were found to be significantly lower in myometrium after labour onset. There was no effect of term or preterm labour on Slit2 expression in foetal membranes. Slit2 mRNA expression was decreased in myometrium treated with LPS and IL-1β. Slit2 siRNA in myometrial cells increased IL-1β-induced pro-inflammatory cytokine gene expression and release (IL-6 and IL-8), COX-2 expression and prostaglandin PGE2 and PGF2α release, and MMP-9 gene expression and pro MMP-9 release. There was no effect of Slit2 siRNA on IL-1β-induced NF-κB transcriptional activity. Our results demonstrate that Slit2 is decreased in human myometrium after labour and our knock-down studies describe an anti-inflammatory effect of Slit2 in myometrial cells.

Differential expression of AP-1 proteins in human myometrium after spontaneous term labour onset

OBJECTIVES

The aims of this study were (i) to determine the localisation of activator protein (AP)-1 family members (cFos, FosB, cJun, JunB and JunD) in human myometrium; and (ii) to determine the effect of human term labour on the expression of AP-1 family of transcription factors in myometrium.

STUDY DESIGN

This localised the AP-1 family members cFos, FosB, cJun, JunB and JunD in human myometrium was performed by immunohistochemistry. The effect of term labour on the expression of these family members at the mRNA and protein level was assessed by qRT-PCR and Western blotting, respectively. The effect of pro-inflammatory stimuli on AP-1 transcriptional activity was assessed using a luciferase assay in primary human myometrial cells.

RESULTS

Immunohistochemical expression of cFos, FosB, cJun, JunB and JunD were all present in human myometrial tissue and displayed cytoplasmic staining. FosB and JunD also displayed nuclear staining. Term labour was associated with an increase in cFos and JunB mRNA and protein expression. On the other hand, JunD mRNA and protein expression was decreased with labour. FosB mRNA was increased with labour, but there was no change at the protein level. There was no change in cJun mRNA or protein expression. AP-1 transcriptional activity was increased in human myometrial cells by the pro-inflammatory cytokine TNF-α. There was, however, no effect of the bacterial products lipopolysaccharide (LPS; TLR4 ligand), iE-DAP (NOD1 ligand), MDP (NOD2 ligand), FSL-1 (TLR2 ligand) or flagellin (TLR5 ligand) on AP-1 transcriptional activity.

CONCLUSION

This study shows that human labour is associated with changes in AP-1 family members. Further studies are required to determine the exact role of the AP-1 family members in myometrium.

The microbiome, parturition, and timing of birth: more questions than answers

The causes of preterm birth are multifactorial, but its association with infection has been well-established. The predominant paradigm describes an ascending infection from the lower genital tract through the cervix and into the presumably sterile fetal membranes and placenta. Thus, an evaluation of the role of the vaginal microbiome in preterm birth is implicated. However, emerging fields of data described in this review suggest that the placenta might not be sterile, even in the absence of clinical infection. We thus propose an additional mechanism for placental colonization and infection: hematogenous spread. When considered in the context of decades of evidence demonstrating a strong risk of recurrence for preterm birth, studies on parturition are ideal for applying the rapidly expanding field of metagenomics and analytic pipelines. The translational implications toward identification of innovative treatments for the prevention of preterm birth are further discussed. In sum, exciting advances in understanding the role of both host and microbiota in parturition and preterm birth are on the horizon.

Effect of silibinin in reducing inflammatory pathways in in vitro and in vivo models of infection-induced preterm birth

Infection-induced preterm birth is the largest cause of infant death and of neurological disabilities in survivors. Silibinin, from milk thistle, exerts potent anti-inflammatory activities in non-gestational tissues. The aims of this study were to determine the effect of silibinin on pro-inflammatory mediators in (i) human fetal membranes and myometrium treated with bacterial endotoxin lipopolysaccharide (LPS) or the pro-inflammatory cytokine IL-1β, and (ii) in preterm fetal membranes with active infection. The effect of silibinin on infection induced inflammation and brain injury in pregnant mice was also assessed. Fetal membranes and myometrium (tissue explants and primary cells) were treated with 200 μM silibinin in the presence or absence of 10 μg/ml LPS or 1 ng/ml IL-1β. C57BL/6 mice were injected with 70 mg/kg silibinin with or without 50 μg LPS on embryonic day 16. Fetal brains were collected after 6 h. In human fetal membranes, silibinin significantly decreased LPS-stimulated expression of IL-6 and IL-8, COX-2, and prostaglandins PGE2 and PGF2α. In primary amnion and myometrial cells, silibinin also decreased IL-1β-induced MMP-9 expression. Preterm fetal membranes with active infection treated with silibinin showed a decrease in IL-6, IL-8 and MMP-9 expression. Fetal brains from mice treated with silibinin showed a significant decrease in LPS-induced IL-8 and ninjurin, a marker of brain injury. Our study demonstrates that silibinin can reduce infection and inflammation-induced pro-labour mediators in human fetal membranes and myometrium. Excitingly, the in vivo results indicate a protective effect of silibinin on infection-induced brain injury in a mouse model of preterm birth.

The TLR2 ligand FSL-1 and the TLR5 ligand Flagellin mediate pro-inflammatory and pro-labour response via MyD88/TRAF6/NF-κB-dependent signalling

PROBLEM

Toll-like receptors (TLRs) 2 and 5 induce inflammation via the adapter proteins myeloid differentiation factor 88 (MyD88) and TNFR-associated factor 6 (TRAF6) and the transcription factor nuclear factor-kappa B (NF-κB). The aims of this study were to determine the effects of the TLR5 ligand flagellin and the TLR2 ligand FSL-1 on pro-inflammatory and pro-labour mediators in human fetal membranes and myometrium, and to establish whether their actions are dependent on MyD88, TRAF6 and NF-κB.

METHOD OF STUDY

Tissue explants were performed to determine the effect of flagellin and FSL-1 on pro-labour mediators in fetal membranes and myometrium. siRNA knockdown was performed in primary amnion and myometrium cells to determine the role of MyD88, TRAF6 and NF-κB.

RESULTS

Flagellin and FSL-1 increased pro-inflammatory cytokines (IL-6 and IL-8), MMP-9 expression and activity, and COX-2 expression and prostaglandin release. siRNA knockdown of TLR2 decreased FSL-1 induced production of IL-6, IL-8, COX-2, prostaglandins and MMP-9; similarly, siRNA knockdown of TLR5 decreased flagellin induced production of these pro-labour mediators. The effects of flagellin and FSL-1 are mediated by MyD88 and TRAF6, as siRNA knockdown of MyD88 and TRAF6 decreased flagellin and FSL-1 induced pro-labour mediators. Additionally, the effects of flagellin and FSL-1 are mediated via NF-κB, as flagellin and FSL-1 increased NF-κB transcriptional activity, and the NF-κB inhibitor BAY 11-7082 attenuated flagellin and FSL-1 induced expression and secretion of pro-labour mediators.

CONCLUSION

TLR2 engagement by the synthetic lipoprotein FSL-1 and TLR5 engagement by bacterial flagellin enhances pro-inflammatory and pro-labour mediators in human fetal membranes and myometrium via MyD88/TRAF6/NF-κB.

SLIT3 is increased in supracervical human foetal membranes and in labouring myometrium and regulates pro-inflammatory mediators

PROBLEM

Inflammation is associated with preterm birth, a worldwide healthcare issue. SLIT3 has a role in inflammation, and thus, the purpose of this study was to determine the effect of SLIT3 on labour mediators in human gestational tissues.

METHOD OF STUDY

SLIT3 protein expression was performed using immunohistochemistry in foetal membranes and myometrium with no labour and after labour. Foetal membranes were also obtained from a distal site (DS) and supracervical site (overlying the cervix; SCS). SLIT3 gene silencing was achieved using siRNA in primary amnion and myometrial cells. Pro-inflammatory and pro-labour mediators were evaluated by qRT-PCR, ELISA and gelatin zymography.

RESULTS

SLIT3 expression was greater in foetal membranes from the SCS compared with DS and in myometrium after term spontaneous labour onset. SLIT3 siRNA in primary amnion and myometrial cells decreased IL-1β-induced pro-inflammatory cytokine gene expression and release (IL-6 and IL-8) and MMP-9 gene expression and release. In amnion cells, SLIT3 siRNA knockdown decreased IL-1β-induced COX-2 expression and prostaglandin PGE2 release. There was no effect of SLIT3 siRNA on IL-1β-induced NF-κB transcriptional activity.

CONCLUSION

Our results demonstrate that SLIT3 is increased with labour, and both our amnion and our myometrial studies describe a pro-inflammatory effect of SLIT3 in these tissues.