Runt-related transcription factor 1 (RUNX1) deficiency attenuates inflammation-induced pro-inflammatory and pro-labour mediators in myometrium

LncRNA H19 Inhibits Keratinocyte Cell Proliferation and Migration by Targeting miR-17-5p/RUNX1 Axis in Chronic Wounds

The migration and proliferation of keratinocytes are critical for re-epithelization during chronic wound healing. Runt-related transcription factor 1 (RUNX1) has been indicated to repress keratinocyte proliferation. Nonetheless, the potential molecular mechanism of RUNX1 in regulating keratinocyte proliferation and migration remains unclear. Cell counting kit-8 and wound-healing assays were implemented for examining keratinocyte viability and migration, respectively. Western blotting and real-time quantitative polymerase chain reaction were utilized for quantifying protein and RNA levels. Luciferase reporter assay was employed for verifying the interaction between RUNX1, miR-17-5p, and long noncoding RNA H19. The results showed that RUNX1 depletion promoted keratinocyte proliferation and migration and repressed extracellular matrix degradation. Mechanistically, H19 upregulated RUNX1 expression by competitively absorbing miR-17-5p. Rescue experiments revealed that overexpressing RUNX1 reversed H19 silencing-mediated effects on the phenotypes of keratinocytes. In conclusion, H19 knockdown promotes keratinocyte proliferation and migration and suppresses extracellular matrix degradation via the miR-17-5p/RUNX1 axis.

RNA-seq and ATAC-seq analysis of CD163+ macrophage-induced progestin-insensitive endometrial cancer cells

BACKGROUND

Progestins are used as fertility-sparing regimens for young patients with stage 1A endometrioid endometrial cancer (EEC) and atypical endometrial hyperplasia (AEH). CD163⁺ macrophages promote estrogen-dependent EEC development, but whether they induce progestin insensitivity remains unclear. This study aimed to investigate the possible effects of CD163⁺ macrophages on progestin response in AEH/EEC patients.

METHODS

The number of infiltrating CD163⁺ macrophages in progestin-insensitive and -sensitive endometrial lesions was compared. The effects of CD163⁺ macrophages on progestin responses and progesterone receptor (PR) expression in EC cells were evaluated in vitro. ATAC-seq and RNA-seq were combined to identify molecular/biological changes induced by CD163⁺ macrophages in progestin-insensitive EC cells.

RESULTS

Increased CD163⁺ macrophage infiltration was significantly associated with progestin insensitivity and longer treatment durations in AEH/EEC patients. Additionally, the number of CD163⁺ macrophages was negatively correlated with PR expression in AEH/EEC tissues. Furthermore, the CD163⁺ macrophage-mediated microenvironment and secreted cytokines downregulated PR expression and impaired the response of EC cells to medroxyprogesterone acetate (MPA). RNA-seq analysis demonstrated that CD163⁺ macrophages antagonized PR signaling by blocking or even reversing MPA-regulated differential gene expression. Based on RNA-seq and ATAC-seq analyses, extracellular matrix (ECM) signaling and ECM-related transcription factors, FOXF2, POU1F1, and RUNX1were identified to potentially be involved in CD163⁺ macrophage-induced progestin insensitivity in endometrial cancer patients.

CONCLUSIONS

We identified CD163⁺ macrophages as an important mediator of progestin desensitization and an unfavorable factor for the efficacy of fertility-preserving treatment in AEH/EEC patients.

Single-cell multimodal analysis identifies common regulatory programs in synovial fibroblasts of rheumatoid arthritis patients and modeled TNF-driven arthritis

Background

Synovial fibroblasts (SFs) are specialized cells of the synovium that provide nutrients and lubricants for the proper function of diarthrodial joints. Recent evidence appreciates the contribution of SF heterogeneity in arthritic pathologies. However, the normal SF profiles and the molecular networks that govern the transition from homeostatic to arthritic SF heterogeneity remain poorly defined.

Methods

We applied a combined analysis of single-cell (sc) transcriptomes and epigenomes (scRNA-seq and scATAC-seq) to SFs derived from naïve and hTNFtg mice (mice that overexpress human TNF, a murine model for rheumatoid arthritis), by employing the Seurat and ArchR packages. To identify the cellular differentiation lineages, we conducted velocity and trajectory analysis by combining state-of-the-art algorithms including scVelo, Slingshot, and PAGA. We integrated the transcriptomic and epigenomic data to infer gene regulatory networks using ArchR and custom-implemented algorithms. We performed a canonical correlation analysis-based integration of murine data with publicly available datasets from SFs of rheumatoid arthritis patients and sought to identify conserved gene regulatory networks by utilizing the SCENIC algorithm in the human arthritic scRNA-seq atlas.

Results

By comparing SFs from healthy and hTNFtg mice, we revealed seven homeostatic and two disease-specific subsets of SFs. In healthy synovium, SFs function towards chondro- and osteogenesis, tissue repair, and immune surveillance. The development of arthritis leads to shrinkage of homeostatic SFs and favors the emergence of SF profiles marked by Dkk3 and Lrrc15 expression, functioning towards enhanced inflammatory responses and matrix catabolic processes. Lineage inference analysis indicated that specific Thy1+ SFs at the root of trajectories lead to the intermediate Thy1+/Dkk3+/Lrrc15+ SF states and culminate in a destructive and inflammatory Thy1− SF identity. We further uncovered epigenetically primed gene programs driving the expansion of these arthritic SFs, regulated by NFkB and new candidates, such as Runx1. Cross-species analysis of human/mouse arthritic SF data determined conserved regulatory and transcriptional networks.

Conclusions

We revealed a dynamic SF landscape from health to arthritis providing a functional genomic blueprint to understand the joint pathophysiology and highlight the fibroblast-oriented therapeutic targets for combating chronic inflammatory and destructive arthritic disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-022-01081-3.

Mechanistic Pathogenesis of Endothelial Dysfunction in Diabetic Nephropathy and Retinopathy

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are microvascular complications of diabetes. Microvascular endothelial cells are thought to be the major targets of hyperglycemic injury. In diabetic microvasculature, the intracellular hyperglycemia causes damages to the vascular endothelium, via multiple pathophysiological process consist of inflammation, endothelial cell crosstalk with podocytes/pericytes and exosomes. In addition, DN and DR diseases development are involved in several critical regulators including the cell adhesion molecules (CAMs), the vascular endothelial growth factor (VEGF) family and the Notch signal. The present review attempts to gain a deeper understanding of the pathogenesis complexities underlying the endothelial dysfunction in diabetes diabetic and retinopathy, contributing to the development of new mechanistic therapeutic strategies against diabetes-induced microvascular endothelial dysfunction.

Silencing of IGF2BP1 restrains ox-LDL-induced lipid accumulation and inflammation by reducing RUNX1 expression and promoting autophagy in macrophages

Atherosclerosis (AS) is a chronic inflammatory disease with the formation and accumulation of macrophage-derived foam cells in the subendothelial space of blood vessels as one major characteristic. Insulin-like growth factor 2 messenger RNA (mRNA) binding protein 1 (IGF2BP1) is an RNA-binding factor and its elevation has been reported to be associated with macrophage infiltration into the atherosclerotic vascular wall. This study aims to investigate the roles of IGF2BP1 in AS-associated foam cell formation. Herein, ApoE-/- mice fed with high-fat diet developed atherosclerotic lesions in the aorta, where IGF2BP1 expression was upregulated and autophagy was impaired. IGF2BP1 expressed in F4/80+ macrophages and coexisted with p62. In vitro, IGF2BP1 expression was upregulated in RAW264.7 macrophages exposed to oxidized low-density lipoprotein (ox-LDL) (100 μg/ml). Interestingly, silencing of IGF2BP1 ameliorated ox-LDL-induced lipid accumulation and inflammation, and enhanced autophagic flux in macrophages. Furthermore, the expression of RUNX family transcription factor 1 (RUNX1), a gene that is able to inhibit autophagy in multiple cell types, was elevated in atherosclerotic aortas and in ox-LDL-treated macrophages. In addition, RNA immunoprecipitation results revealed that IGF2BP1 is bound to RUNX1 mRNA. Alterations induced by IGF2BP1 knockdown in ox-LDL-treated macrophages were abolished by RUNX1 overexpression. Furthermore, after autophagy inhibitor 3-methyladenine administration, silencing of IGF2BP1-reduced lipid accumulation and inflammation were recovered in RAW264.7 cells. In summary, our study demonstrated that silencing of IGF2BP1 restrained ox-LDL-induced lipid accumulation and inflammation by reducing RUNX1 expression and facilitating autophagy in macrophages. IGF2BP1/RUNX1 axis may be considered as a potential therapeutic target in AS.

The short-chain fatty acids butyrate and propionate protect against inflammation-induced activation of mediators involved in active labor: implications for preterm birth

Spontaneous preterm birth is a global health issue affecting up to 20% of pregnancies and leaves a legacy of neurodevelopmental complications. Inflammation has been implicated in a significant proportion of preterm births, where pro-inflammatory insults trigger production of additional pro-inflammatory and pro-labor mediators. Thus, novel therapeutics that can target inflammation may be a novel avenue for preventing preterm birth and improving adverse fetal outcomes. Short-chain fatty acids (SCFAs), such as butyrate and propionate, are dietary metabolites produced by bacterial fermentation of fiber in the gut. SCFAs are known to possess anti-inflammatory properties and have been found to function through G-coupled-receptors and histone deacetylases. Therefore, this study aimed to investigate the effect of SCFAs on pro-inflammatory and pro-labor mediators in an in vitro model of preterm birth. Primary human cells isolated from myometrium and fetal membranes (decidua, amnion mesenchymal and amnion epithelial cells) were stimulated with the pro-inflammatory cytokines tumor necrosis factor alpha (TNF) or interleukin 1B (IL1B). The SCFAs butyrate and propionate suppressed inflammation-induced expression of pro-inflammatory cytokines and chemokines, adhesion molecules, the uterotonic prostaglandin PGF2alpha and enzymes involved in remodeling of myometrium and degradation of the fetal membranes. Notably, propionate and butyrate also suppressed inflammation-induced prostaglandin signaling and myometrial cell contraction. These effects appear to be mediated through suppression of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) activation. These results suggest that the SCFAs may be able to prevent myometrial contractions and rupture of membranes. Further in vivo studies are warranted to identify the efficacy of SCFAs as a novel anti-inflammatory therapeutic to prevent inflammation-induced spontaneous preterm birth.

In vitro selenium supplementation suppresses key mediators involved in myometrial activation and rupture of fetal membranes

Spontaneous preterm birth, which can affect up to 20% of all pregnancies, is the greatest contributor to perinatal morbidity and mortality. Infection is the leading pathological cause of spontaneous preterm birth. Infection activates the maternal immune system, resulting in the upregulation of pro-inflammatory and pro-labor mediators that activate myometrial contractions and rupture of fetal membranes. Anti-inflammatory agents therefore have the potential for the prevention of spontaneous preterm birth. Selenium, an essential micronutrient, has been shown to be a potent anti-inflammatory regulator. Notably, clinical and epidemiological studies have suggested a link between selenium and preterm birth. Thus, the aim of this study was to assess the effect of selenite (an inorganic form of selenium) on the expression of pro-inflammatory and pro-labor mediators in human gestational tissues. Human fetal membranes and myometrium were pre-incubated with or without selenite before incubation with the bacterial product lipopolysaccharide (LPS) to stimulate inflammation associated with preterm birth. Selenite blocked LPS-induced expression of pro-inflammatory cytokines and chemokines and enzymes involved in remodelling of myometrium and degradation of fetal membranes. Of note, selenite also suppressed myometrial activation induced by inflammation as evidenced by a decrease in LPS-induced prostaglandin signalling and myometrial cell contractility. These effects of selenite were mediated by the MAPK protein ERK as selenite blunted LPS induced activation of ERK. In conclusion, selenite suppresses key mediators involved in inflammation induced activation of mediators involved in active labor in human fetal membranes and myometrium. These findings support recent clinical studies demonstrating selenium supplementation is associated with decreased incidence of spontaneous preterm birth.

Integrated bioinformatics analysis reveals novel key biomarkers and potential candidate small molecule drugs in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is the metabolic disorder that appears during pregnancy. The current investigation aimed to identify central differentially expressed genes (DEGs) in GDM. The transcription profiling by array data (E-MTAB-6418) was obtained from the ArrayExpress database. The DEGs between GDM samples and non-GDM samples were analyzed. Functional enrichment analysis were performed using ToppGene. Then we constructed the protein–protein interaction (PPI) network of DEGs by the Search Tool for the Retrieval of Interacting Genes database (STRING) and module analysis was performed. Subsequently, we constructed the miRNA–hub gene network and TF–hub gene regulatory network. The validation of hub genes was performed through receiver operating characteristic curve (ROC). Finally, the candidate small molecules as potential drugs to treat GDM were predicted by using molecular docking. Through transcription profiling by array data, a total of 869 DEGs were detected including 439 up-regulated and 430 down-regulated genes. Functional enrichment analysis showed these DEGs were mainly enriched in reproduction, cell adhesion, cell surface interactions at the vascular wall and extracellular matrix organization. Ten genes, HSP90AA1, EGFR, RPS13, RBX1, PAK1, FYN, ABL1, SMAD3, STAT3 and PRKCA were associated with GDM, according to ROC analysis. Finally, the most significant small molecules were predicted based on molecular docking. This investigation identified hub genes, signal pathways and therapeutic agents, which might help us, enhance our understanding of the mechanisms of GDM and find some novel therapeutic agents for GDM.

GIT2 deficiency attenuates inflammation-induced expression of pro-labor mediators in human amnion and myometrial cells†

Untimely activation of the inflammatory response by sterile or infective insults in uterine tissues can result in preterm birth. Pro-inflammatory cytokines and pathogenic activation of toll-like receptors (TLRs) initiate a biochemical cascade of events leading to myometrial activation and contractility, cervical dilatation, and rupture of the chorioamniotic membranes. GIT2 is a signaling protein known to play a role in innate and adaptive immunity; however, its role in the inflammatory pathways of human labor is not known. In this article, we report that GIT2 expression is lower in human myometrium and fetal membranes with term labor, and in preterm amnion with histological chorioamnionitis. GIT2 knockdown by siRNA in primary myometrial and amnion cells exhibited reduced expression of pro-inflammatory cytokines and chemokines in response to inflammatory challenge by cytokines or TLR ligands. In addition, the pro-inflammatory cytokines IL1B and TNF could not induce the expression of extracellular matrix degrading enzymes in GIT2-deficient amnion cells. Myometrial activation in response to pro-inflammatory cytokines was also significantly suppressed in GIT2-deficient cells as evidenced by decreased prostaglandin release and expression of contraction-associated proteins. Further to this, collagen gel assays demonstrated that TNF had a reduced ability to induce myometrial contractility in situ in GIT2-deficient myometrial cells compared to control-transfected cells. In summary, the loss of GIT2 diminishes the effects inflammatory mediators have in promoting myometrial contraction and fetal membrane rupture in vitro, suggesting that GIT2 could be a possible target for preterm birth therapies.

MiR-194 targets Runx1/Akt pathway to reduce renal fibrosis in mice with unilateral ureteral obstruction

PURPOSE

Chronic kidney disease (CKD) has become a global public health problem and accompanied by renal fibrosis. MiR-194, a tumor suppressor gene, has been previously reported to be associated with the pathogenesis of tissue fibrosis. However, the role of miR-194 in the pathogenesis of renal fibrosis remains unknown.

METHODS

A renal fibrosis model was constructed by unilateral ureteral obstruction (UUO) in male C57BL/6 mice. HE and MASSON stainings were used for histological analysis. The expression level of miR-194 was detected by RT-qPCR. The protein expression was detected by western blotting. The levels of inflammatory cytokines were detected by ELISA. The relationship between miR-194 and Runx1 was further verified by dual luciferase reporter assay.

RESULTS

The results showed that miR-194 level was downregulated in kidney tissue of UUO mice, accompanied by significantly pathological damage and renal fibrosis. MiR-194 mimics significantly reduced pathological damage and alleviated renal fibrosis that caused by UOO, and inhibited the expression levels of α-SMA and collagen I. In addition, miR-194 mimics also reduced the expression level of serum inflammatory factors. Moreover, in vitro analysis indicated that Runx1 was a downstream target gene of miR-194. Furthermore, mechanism analysis indicated that miR-194 reduced mouse renal fibrosis by inhibiting the Runx1/AKT pathway in vivo and in vitro.

CONCLUSION

The present findings suggested that miR-194 targets Runx1/Akt pathway to reduce renal fibrosis in UOO-induced mice. This study provides a novel strategy for the prevention and treatment of renal fibrosis.

RUNX1: an emerging therapeutic target for cardiovascular disease

Runt-related transcription factor-1 (RUNX1), also known as acute myeloid leukaemia 1 protein (AML1), is a member of the core-binding factor family of transcription factors which modulate cell proliferation, differentiation, and survival in multiple systems. It is a master-regulator transcription factor, which has been implicated in diverse signalling pathways and cellular mechanisms during normal development and disease. RUNX1 is best characterized for its indispensable role for definitive haematopoiesis and its involvement in haematological malignancies. However, more recently RUNX1 has been identified as a key regulator of adverse cardiac remodelling following myocardial infarction. This review discusses the role RUNX1 plays in the heart and highlights its therapeutic potential as a target to limit the progression of adverse cardiac remodelling and heart failure.

Targeting bromodomain-containing proteins to prevent spontaneous preterm birth

Preterm birth is a global healthcare challenge. Spontaneous preterm birth (sPTB) is commonly caused by inflammation, yet there are currently no effective therapies available. The Bromodomain and Extra-Terminal motif (BET) proteins, Bromodomain-containing protein (Brd) 2 (Brd2), Brd3 and Brd4 regulate inflammation in non-gestational tissues. The roles of Brd2-4 in human pregnancy are unknown. Using human and mouse models, the present study has identified the Brd proteins part of the process by which inflammation induces parturition. Using human clinical samples, we demonstrate that labor and infection increase the expression of Brds in the uterus and fetal membranes. In primary human myometrial, amnion and decidual cells, we found that global Brd protein inhibition, as well as selective inhibition of Brds, suppressed inflammation-induced expression of mediators involved in myometrial contractions and rupture of fetal membranes. Importantly, studies in the mouse model demonstrate that the pan-Brd inhibitor JQ1 reduced intrauterine inflammation induced by bacterial endotoxin LPS as well as decreasing the effectiveness of LPS to induce parturition. These results implicate BET proteins as novel therapeutic targets for reducing inflammation associated with spontaneous preterm labor.

Inhibition of GPR91 Reduces Inflammatory Mediators Involved in Active Labor in Myometrium

Results

GPR91 mRNA expression was significantly higher in myometrium from women during term spontaneous labor compared to no labor. Likewise, in mice, GPR91 mRNA expression was significantly upregulated in myometrium during inflammation-induced preterm labor compared to preterm no labor. In myometrial cells, IL1B and TNF significantly increased GPR91 mRNA expression. Knockdown of GPR91 by siRNA in myometrial cells significantly suppressed the secretion and/or expression of IL1B- and TNF-induced proinflammatory cytokines (GM-CSF, IL1A, IL1B, and IL6) and chemokines (CXCL8 and CCL2), myometrial contractility (expression of the contraction-associated proteins PTGFR and CX43, secretion of the uterotonic PGF_2α, and in situ collagen gel contraction), and the transcription factor NF-κB.

Conclusion

Our findings demonstrate that GPR91 is involved in the genesis of proinflammatory and prolabor mediators induced by IL1B or TNF and collectively suggest that GPR91 may contribute to augmentation of the labor processes.

Crosstalk between tubular epithelial cells and glomerular endothelial cells in diabetic kidney disease

In recent years, although the development of clinical therapy for diabetic kidney disease (DKD) has made great progress, the progression of DKD still cannot be controlled. Therefore, further study of the pathogenesis of DKD and improvements in DKD treatment are crucial for prognosis. Traditional studies have shown that podocyte injury plays an important role in this process. Recently, it has been found that glomerulotubular balance and tubuloglomerular feedback (TGF) may be involved in the progression of DKD. Glomerulotubular balance is the specific gravity absorption of the glomerular ultrafiltrate by the proximal tubules, which absorbs only 65% to 70% of the ultrafiltrate. This ensures that the urine volume will not change much regardless of whether the glomerular filtration rate (GFR) increases or decreases. TGF is one of the significant mechanisms of renal blood flow and self-regulation of GFR, but how they participate in the development of DKD in the pathological state and the specific mechanism is not clear. Injury to tubular epithelial cells (TECs) is the key link in DKD. Additionally, injury to glomerular endothelial cells (GECs) plays a key role in the early occurrence and development of DKD. However, TECs and GECs are close to each other in anatomical position and can crosstalk with each other, which may affect the development of DKD. Therefore, the purpose of this review was to summarize the current knowledge on the crosstalk between TECs and GECs in the pathogenesis of DKD and to highlight specific clinical and potential therapeutic strategies.

Role of IRG1 in Regulating Pro-inflammatory and Pro-labor Mediators in Human Myometrium

Preterm birth is a major contributor to neonatal deaths and associated long-term morbidities for the survivors, yet therapies remain elusive, given our incomplete understanding of the mechanisms driving human labor and delivery. Human labor is an inflammatory process, and we investigated whether IRG1 (immunoresponsive gene-1) plays a role in these processes. We demonstrate that IRG1 mRNA and protein expression is significantly increased in myometrium with human term labor, compared to no labor samples, and with preterm (LPS) labor in a mouse model. Pro-labor mediators such as pro-inflammatory cytokines TNF and IL1B, and TLR ligands fsl-1, flagellin, LPS, and poly(I:C) also increased IRG1 mRNA expression in myometrial explants. IRG1 silencing, using siRNA in primary myometrial cells, displayed a decrease in the expression of inflammation-induced pro-inflammatory cytokines (IL1A, IL6), chemokines (CCL2, CXCL1, CXCL8), adhesion molecules (ICAM1, VCAM1), and contractility (PTGFR mRNA expression, prostaglandin F_2α release, and in situ gel contraction assay). Our results suggest that IRG1 is involved when pro-labor mediators activate the inflammatory processes of human labor, warranting further investigation.

Expression and function of macrophage-inducible C-type lectin (Mincle) in inflammation driven parturition in fetal membranes and myometrium

The pivotal role of inflammatory processes in human parturition is well known, but not completely understood. We have performed a study to examine the role of macrophage-inducible C-type lectin (Mincle) in inflammation-associated parturition. Using human samples, we show that spontaneous labour is associated with up-regulated Mincle expression in the myometrium and fetal membranes. Mincle expression was also increased in fetal membranes and myometrium in the presence of pro-labour mediators, the proinflammatory cytokines interleukin (IL)-1B and tumour necrosis factor (TNF), and Toll-like receptor (TLR) ligands fsl-1, poly(I:C), lipopolysaccharide (LPS) and flagellin. These clinical studies are supported by mouse studies, where an inflammatory challenge in a mouse model of preterm birth increased Mincle expression in the uterus. Importantly, elimination of Mincle decreased the effectiveness of proinflammatory cytokines and TLR ligands to induce the expression of pro-labour mediators; namely, proinflammatory cytokines and chemokines, contraction-associated proteins and prostaglandins, and extracellular matrix remodelling enzymes, matrix metalloproteinases. The data presented in this study suggest that Mincle is required when inflammatory activation precipitates parturition.

Dominant inflammatory profile of the placenta in a preterm labor mouse model

Objective: Despite a growing association between inflammation and preterm labor, the underlying mechanisms explaining the development of preterm labor after infection are still poorly understood. Here, we use RNA-sequencing to characterize the transcriptome changes of placenta tissue in a preterm labor mouse model.Materials and methods: On day 15.5 of gestation, BALB/c mice received intrauterine injection of LPS to mimic preterm labor. A comprehensive catalog of genes was obtained using RNA-sequences and followed by bioinformatics analysis. The NOD-like receptor signaling pathway (Nod2, Cxcl1, Cxcl2, and IL-1β) and two downregulated genes (Ctsg and Snca) were selected for validating the results using qPCR analysis.Results: We identified 155 differentially expressed genes (DEGs), 84 biological processes and 45 pathways in the placenta using RNA-seq. Fifty-four biological processes could be categorized as immune-related processes and 33 pathways were mainly related to immune disease and infections. All genes were consistent between the RNA-seq and qPCR analyses.Conclusions: The dominant role for inflammatory biological processes and pathways in placenta can lead to preterm labor.

Potent anti-inflammatory effects of honokiol in human fetal membranes and myometrium

BACKGROUND

Preterm birth is the most prominent complication attributing to poor pregnancy and neonatal outcome. Infection is most commonly implicated in preterm birth; it initiates a cascade of inflammatory events that leads to the rupture of fetal membranes and spontaneous uterine contractions. Anti-inflammatory agents may thus be a therapeutic approach to prevent the premature rupture of fetal membranes and block contractions. In non-gestational tissues, the polyphenol honokiol has been shown to possess potent anti-inflammatory properties.

PURPOSE

The aim of this study was to investigate the effect of honokiol on pro-inflammatory mediators in human gestational tissues.

METHODS

Fetal membranes, myometrium and freshly isolated amnion cells and primary myometrial cells were treated with honokiol in the absence or presence of the products lipopolysaccharide (LPS) and fibroblast-stimulating lipopeptide-1 (fsl-1), the viral dsRNA analogue polyinosinic:polycytidylic acid (poly(I:C)) or the pro-inflammatory cytokines TNF or IL1B. A luciferase assay was used to determine the effect of honokiol on nuclear factor kappa B (NF-κB) RelA transcriptional activity.

RESULTS

Honokiol significantly decreased pro-inflammatory cytokine (IL1A, IL6) and chemokine (CXCL8, CXCL1, CCL2) mRNA expression and secretion from fetal membranes (amnion and choriodecidua) and myometrium stimulated with LPS, fsl-1 or poly(I:C). In amnion cells, honokiol also significantly decreased the expression and secretion of the extracellular matrix degrading enzyme MMP9. Moreover, in myometrium, honokiol significantly suppressed the expression of the contraction associated protein PTGFR, the secretion of the uterotonic prostaglandins PGE₂ and PGF_2α, and blocked TNF-induced myometrial cell contractility. Finally, honokiol significantly suppressed IL1B- and TNF-induced NF-κB RelA transcriptional activity in primary amnion and myometrial cells.

CONCLUSIONS

Honokiol reduced the expression of pro-inflammatory and pro-labour mediators in human amnion, choriodecidua and myometrium and that this may be facilitated through the suppression of NF-κB activation. These results indicate that the polyphenol honokiol may be a potent therapeutic for the prevention of preterm birth.

Expression and regulation of metallothioneins in myometrium and fetal membranes

PROBLEM

Metallothioneins (MTs) play important roles in regulating oxidative stress, inflammation, and hormone signaling. These processes play a major role in labor at term and preterm. The aims of this study were to characterize (a) temporal- and labor-associated changes and (b) the effect of pro-inflammatory and pro-labor insults on the expression of MT1 isoforms, MT2A, MT3, and MT4 in fetal membranes and myometrium.

METHOD OF STUDY

The expression of MTs was assessed in fetal membranes and myometrium from nonlaboring and laboring women at preterm and term by RT-qPCR. Tissue explants were used to assess the effect of pro-inflammatory cytokines and Toll-like receptor (TLR) ligands on the expression of MTs in fetal membranes and myometrium.

RESULTS

In fetal membranes, the expression of MT1A, MT1E, MT1F, MT1X, and MT2A was higher at term compared with preterm. Preterm labor and preterm histological chorioamnionitis were associated with increased expression of MT1A, MT1G, MT1M, MT1X, MT2A, and MT3. Term labor was associated with increased expression of MT1A, MT1F, MT1X, MT2A, and MT3 in fetal membranes and expression of MT1A, MT1E, MT1F, MT1G, MT1M, MT1X, MT2A, and MT3 in myometrium. Pro-inflammatory cytokines and TLR ligands increased the expression of MT1A, MT1E, MT1F, MT1G, MT1H, MT1X, and MT2A in fetal membranes and myometrium.

CONCLUSION

Temporal-, labor-, and infection-associated increases in MT1 isoforms, MT2A, and MT3 have been observed in fetal membranes and/or myometrium. Furthermore, pro-inflammatory cytokines and bacterial and viral products increased the expression of MT1 isoforms, MT2A, MT3, and MT4 mRNA expression in fetal membranes and myometrium.