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Lappas M.,University of Melbourne | Lappas M.,Mercy Perinatal Research Center
Molecular and Cellular Endocrinology

The inflammatory process plays a pivotal role during the pathogenesis of human labour, both at term and preterm. Visfatin levels increase during normal human pregnancy and in infection associated preterm labour. The effects of visfatin in the processes of human labour and delivery, however, are not known. The aim of this study was to determine the effect of visfatin on the expression and release of pro-labour mediators in human placenta. Samples were obtained from normal pregnancies at the time of Caesarean section. Human placenta was incubated in the absence (basal control) or presence of a 50ng/ml visfatin for 24h (n=6). Inflammatory gene expression was analysed by quantitative RT-PCR (qRT-PCR), the medium was collected and cytokine, prostaglandin and 8-isoprostane (marker of oxidative stress) release was quantified by ELISA, and secretory protease activity by zymography. Visfatin significantly increased IL-6 and IL-8 gene expression and secretion, COX-2 expression and resultant prostaglandin (PG) E 2 and PGF 2α release, and 8-isoprostane release. There was, however, no effect of visfatin on pro MMP-9 enzyme activity. These actions of visfatin were elicited via the nuclear factor-κB (NF-κB) pathway as visfatin induced the degradation of IκB-α (inhibitor of NF-κB) whilst increasing NF-κB p65 DNA binding activity. Further to this, visfatin-induced pro-labour responses were abrogated by treatment with the NF-κB inhibitor BAY 11-7082. Collectively, these data indicate that visfatin activates pro-inflammatory cytokine release and phospholipid metabolism in human placenta via activation of the NF-κB pathway. Thus, visfatin represents a novel cytokine linked to the events of human labour initiation. © 2011 Elsevier Ireland Ltd. Source

Lappas M.,University of Melbourne | Lappas M.,Mercy Perinatal Research Center
Mediators of Inflammation

A prominent feature of inflammatory diseases is endothelial dysfunction. Factors associated with endothelial dysfunction include proinflammatory cytokines, adhesion molecules, and matrix degrading enzymes. At the transcriptional level, they are regulated by the histone deacetylase sirtuin (SIRT) 1 via its actions on the proinflammatory transcription factor nuclear factor- κ B (NF- κ B). The role of SIRT6, also a histone deacetylase, in regulating inflammation in endothelial cells is not known. The aim of this study was to determine the effect of SIRT6 knockdown on inflammatory markers in human umbilical vein endothelial cells (HUVECs) in the presence of lipopolysaccharide (LPS). LPS decreased expression of SIRT6 in HUVECs. Knockdown of SIRT6 increased the expression of proinflammatory cytokines (IL-1 β, IL-6, IL-8), COX-prostaglandin system, ECM remodelling enzymes (MMP-2, MMP-9 and PAI-1), the adhesion molecule ICAM-1, and proangiogenic growth factors VEGF and FGF-2; cell migration; cell adhesion to leukocytes. Loss of SIRT6 increased the expression of NF- κ B, whereas overexpression of SIRT6 was associated with decreased NF- κ B transcriptional activity. Taken together, these results demonstrate that the loss of SIRT6 in endothelial cells is associated with upregulation of genes involved in inflammation, vascular remodelling, and angiogenesis. SIRT6 may be a potential pharmacological target for inflammatory vascular diseases. © 2012 Martha Lappas. Source

Lappas M.,Mercy Perinatal Research Center | Lappas M.,University of Melbourne
Journal of Perinatology

Objective:To determine the effect of pre-existing maternal obesity and gestational diabetes mellitus (GDM) on the circulating levels of insulin growth factor-binding protein (IGFBPs) in cord and maternal plasma.Study Design:IGFBP-1-7 levels were measured on maternal and cord plasma from women with normal glucose tolerance (NGT) (30 non-obese and 36 obese) and GDM (44 non-obese and 26 obese) at the time of term elective cesarean section.Result:Maternal plasma IGFBP-1, IGFBP-6 and IGFBP-rP1 concentrations were significantly lower in NGT obese compared with NGT non-obese women and in non-obese GDM women compared with non-obese NGT women. In cord plasma, IGFBP-1-3 and IGFBP-rP1 concentrations were significantly lower in NGT obese compared with NGT non-obese women and in non-obese GDM women compared with non-obese NGT women. Significant positive correlations were observed between maternal and cord plasma IGFBP-1 and IGFBP-rP1 levels and maternal insulin resistance. In cord plasma, significant positive correlations were observed between IGFBP-1-3 and IGFBP-rP1 levels and fetal insulin resistance. Fetal birthweight was inversely correlated with maternal plasma IGFBP-1 levels and cord plasma IGFBP-1 and IGFBP-2 levels. When corrected for maternal body mass index, the only significant relationship that still existed was between cord plasma IGFBP-1 concentrations and fetal birthweight.Conclusion:At the time of term cesarean section, pre-existing maternal obesity and GDM are associated with lower IGFBP levels in maternal and cord plasma. Alterations in circulating IGF and IGFBPs may alter birthweight and/or neonatal adiposity. This may lead to alterations in optimal growth trajectory and lead to metabolic disorders later in life. © 2015 Nature America, Inc. Source

Lappas M.,University of Melbourne | Lappas M.,Mercy Perinatal Research Center
Biology of Reproduction

Preterm birth remains one of the most important issues facing perinatal medicine today, with chronic inflammation and/or infection being the biggest etiological factor. The nucleotide oligomerization domain (NOD) intracellular molecules recognize a wide range of microbial products as well as other intracellular danger signals, thereby initiating inflammation through activation of nuclear factor KB (NFKB), a central regulator of the terminal processes of human labor and delivery. The aims of this study were to determine the effect of 1) human labor, proinflammatory cytokines, and bacterial endotoxin LPS on NOD1 and NOD2 expression and 2) NOD1 and NOD2 activation on the expression of prolabor mediators in human fetal membranes and myometrium. NOD1 and NOD2 expression was significantly higher in fetal membranes and myometrium after spontaneous labor when compared to nonlaboring tissues. Bacterial endotoxin LPS and the proinflammatory cytokines TNF and IL1B significantly increased NOD2, but not NOD1, expression. Furthermore, LPS-induced NOD2 expression was decreased by the NFKB inhibitor BAY 11-7082. In both fetal membranes and myometrium, the NOD1 ligand bacterial iEDAP and the NOD2 ligand bacterial MDP significantly increased the expression and secretion of proinflammatory cytokines (IL6 and IL8), cyclooxygenase (PTGS2) expression and subsequent release of prostaglandins PGE2 and PGF2alpha, and the expression and activity of MMP9. The effects of these NOD1 and NOD2 ligands were mediated via NFKB, as 1) both iE-DAP and MDP significantly increased NFKB activation and 2) the NFKB inhibitor BAY 11-7082 attenuated iE-DAP- and MDP-induced expression and secretion of prolabor mediators. In conclusion, NOD1 and NOD2 are increased in laboring fetal membranes and myometrium and with bacterial infection. Agonist activation of NOD1 and NOD2 by bacterial products leads to NFKB activation and transcription of NFKB induced prolabor genes. NOD1 and NOD2 may thus represent therapeutic targets for the treatment and/or management of preterm birth. © 2013 by the Society for the Study of Reproduction, Inc. Source

Lappas M.,University of Melbourne | Lappas M.,Mercy Perinatal Research Center
American Journal of Reproductive Immunology

Problem: Interleukin-1β (IL-1β) is a pro-inflammatory cytokine that is involved in human parturition, especially in the context of infection-induced preterm birth. Caspase-1 is a key component of inflammasomes, which are activated upon infection to trigger the maturation of IL-1β. Method of study: To determine the effect of human labour on caspase-1 activation in human foetal membranes and myometrium. In addition, the mechanisms by which inflammasome activation regulates IL-1β production were also be assessed. Results: Higher caspase-1 gene and protein expression were detected in foetal membranes myometrium obtained from term labouring women when compared with samples taken from non labouring women. Lipopolysaccharide induced the transcription and secretion of IL-1β from foetal membranes and myometrium; both events were dependent on nuclear factor kappa B (NF-κB). However, levels of extracellular IL-1β were greatly increased by subsequent treatment with the potassium-proton ionophore Adenosine triphosphate (ATP) or nigericin; an effect that was dependent on active caspase-1. Additionally, ATP induced IL-1β secretion via the purinergic P2X7 receptor, whereas the pannexin-1 channel was required for nigericin induced IL-1β secretion. Conclusion: Taken together, these results demonstrate that caspase-1 activation is increased with human labour in foetal membranes and myometrium, and is required for infection-induced IL-1β secretion. © 2013 John Wiley & Sons Ltd. Source

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