Low dose aspirin prevents endothelial dysfunction in the aorta and foetal loss in pregnant mice infected with influenza A virus.

Influenza A virus (IAV) infection in pregnancy resembles a preeclamptic phenotype characterised by vascular dysfunction and foetal growth retardation. Given that low dose aspirin (ASA) is safe in pregnancy and is used to prevent preeclampsia, we investigated whether ASA or NO-conjugated aspirin, NCX4016, resolve vascular inflammation and function to improve offspring outcomes following IAV infection in pregnant mice. Pregnant mice were intranasally infected with a mouse adapted IAV strain (Hkx31; 104 plaque forming units) and received daily treatments with either 200µg/kg ASA or NCX4016 via oral gavage. Mice were then culled and the maternal lungs and aortas collected for qPCR analysis, and wire myography was performed on aortic rings to assess endothelial and vascular smooth muscle functionality. Pup and placentas were weighed and pup growth rates and survival assessed. IAV infected mice had an impaired endothelial dependent relaxation response to ACh in the aorta, which was prevented by ASA and NCX4016 treatment. ASA and NCX4016 treatment prevented IAV dissemination and inflammation of the aorta as well as improving the pup placental ratios in utero, survival and growth rates at post-natal day 5. Low dose ASA is safe to use during pregnancy for preeclampsia and this study demonstrates that ASA may prove a promising treatment for averting the significant vascular complications associated with influenza infection during pregnancy.

TLR9 Monotherapy in Immune-Competent Mice Suppresses Orthotopic Prostate Tumor Development.

Prostate cancer is ranked second in the world for cancer-related deaths in men, highlighting the lack of effective therapies for advanced-stage disease. Toll-like receptors (TLRs) and immunity have a direct role in prostate cancer pathogenesis, but TLR9 has been reported to contribute to both the progression and inhibition of prostate tumorigenesis. To further understand this apparent disparity, we have investigated the effect of TLR9 stimulation on prostate cancer progression in an immune-competent, syngeneic orthotopic mouse model of prostate cancer. Here, we utilized the class B synthetic agonist CPG-1668 to provoke a TLR9-mediated systemic immune response and demonstrate a significant impairment of prostate tumorigenesis. Untreated tumors contained a high abundance of immune-cell infiltrates. However, pharmacological activation of TLR9 resulted in smaller tumors containing significantly fewer M1 macrophages and T cells. TLR9 stimulation of tumor cells in vitro had no effect on cell viability or its downstream transcriptional targets, whereas stimulation in macrophages suppressed cancer cell growth via type I IFN. This suggests that the antitumorigenic effects of CPG-1668 were predominantly mediated by an antitumor immune response. This study demonstrated that systemic TLR9 stimulation negatively regulates prostate cancer tumorigenesis and highlights TLR9 agonists as a useful therapeutic for the treatment of prostate cancer.

Cigarette Smoke Exposure Induces Neurocognitive Impairments and Neuropathological Changes in the Hippocampus.

Background and Objective: Neurocognitive dysfunction is present in up to ∼61% of people with chronic obstructive pulmonary disease (COPD), with symptoms including learning and memory deficiencies, negatively impacting the quality of life of these individuals. As the mechanisms responsible for neurocognitive deficits in COPD remain unknown, we explored whether chronic cigarette smoke (CS) exposure causes neurocognitive dysfunction in mice and whether this is associated with neuroinflammation and an altered neuropathology. Methods: Male BALB/c mice were exposed to room air (sham) or CS (9 cigarettes/day, 5 days/week) for 24 weeks. After 23 weeks, mice underwent neurocognitive tests to assess working and spatial memory retention. At 24 weeks, mice were culled and lungs were collected and assessed for hallmark features of COPD. Serum was assessed for systemic inflammation and the hippocampus was collected for neuroinflammatory and structural analysis. Results: Chronic CS exposure impaired lung function as well as driving pulmonary inflammation, emphysema, and systemic inflammation. CS exposure impaired working memory retention, which was associated with a suppression in hippocampal microglial number, however, these microglia displayed a more activated morphology. CS-exposed mice showed changes in astrocyte density as well as a reduction in synaptophysin and dendritic spines in the hippocampus. Conclusion: We have developed an experimental model of COPD in mice that recapitulates the hallmark features of the human disease. The altered microglial/astrocytic profiles and alterations in the neuropathology within the hippocampus may explain the neurocognitive dysfunction observed during COPD.

Targeting Evolutionary Conserved Oxidative Stress and Immunometabolic Pathways for the Treatment of Respiratory Infectious Diseases.

Significance: Up until recently, metabolism has scarcely been referenced in terms of immunology. However, emerging evidence has shown that immune cells undergo an adaptation of metabolic processes, known as the metabolic switch. This switch is key to the activation, and sustained inflammatory phenotype in immune cells, which includes the production of cytokines and reactive oxygen species (ROS) that underpin infectious diseases, respiratory and cardiovascular disease, neurodegenerative disease, as well as cancer. Recent Advances: There is a burgeoning body of evidence that immunometabolism and redox biology drive infectious diseases. For example, influenza A virus (IAV) utilizes endogenous ROS production via NADPH oxidase (NOX)2-containing NOXs and mitochondria to circumvent antiviral responses. These evolutionary conserved processes are promoted by glycolysis, the pentose phosphate pathway, and the tricarboxylic acid (TCA) cycle that drive inflammation. Such metabolic products involve succinate, which stimulates inflammation through ROS-dependent stabilization of hypoxia-inducible factor-1α, promoting interleukin-1ß production by the inflammasome. In addition, itaconate has recently gained significant attention for its role as an anti-inflammatory and antioxidant metabolite of the TCA cycle. Critical Issues: The molecular mechanisms by which immunometabolism and ROS promote viral and bacterial pathology are largely unknown. This review will provide an overview of the current paradigms with an emphasis on the roles of immunometabolism and ROS in the context of IAV infection and secondary complications due to bacterial infection such as Streptococcus pneumoniae. Future Directions: Molecular targets based on metabolic cell processes and ROS generation may provide novel and effective therapeutic strategies for IAV and associated bacterial superinfections.

Placental Ras Regulates Inflammation Associated with Maternal Obesity.

Heightened placental inflammation and dysfunction are commonly associated in pregnant obese women compared to their pregnant lean counterparts. The small GTPase superfamily members known as the rat sarcoma viral oncogene homolog (Ras) proteins, in particular, the K-Ras and H-Ras isoforms, have been implicated to regulate inflammation. The aims were to determine the placental Ras expression and activity with maternal obesity and its role in regulating placental inflammation. Human placenta was obtained at term Caesarean section from lean and obese pregnant women to determine the effect of maternal obesity on Ras protein expression and activity. To determine the effect of Ras on inflammation induced by bacterial endotoxin LPS and proinflammatory cytokines TNF-α or IL-1ß, the chemical inhibitor lonafarnib (total Ras inhibitor) and siRNA (siKRAS and siHRAS) were used. Total Ras protein expression together with combined K-Ras and H-Ras activity was significantly increased in the placenta of obese pregnant women and when stimulated with LPS, IL-1ß, or TNF-α. Lonafarnib significantly suppressed LPS-, IL-1ß-, or TNF-α-induced IL-6, IL-8, MCP-1, and GRO-α expression and secretion in placental tissue. Primary trophoblast cells transfected with siKRAS or siHRAS demonstrated only K-Ras silencing significantly decreased IL-1ß-, TNF-α-, or LPS-induced IL-6, IL-8, and MCP-1 expression and secretion. Furthermore, siKRAS significantly reduced downstream ERK-1/2 activation induced by LPS. In trophoblast cells, ERK-1/2 signalling is required for IL-6, IL-8, MCP-1, and GRO-α secretion. These studies implicate a role for K-Ras in regulating inflammation in human placenta. Suppressing overactive placental K-Ras function may prevent adverse fetal outcomes complicated by maternal obesity.

The immunoproteasome inhibitor ONX-0914 regulates inflammation and expression of contraction associated proteins in myometrium.

There are currently no effective treatments to prevent spontaneous preterm labor. The precise upstream biochemical pathways that regulate the transition between uterine quiescence during pregnancy and contractility during labor remain unclear. It is well known however that intrauterine inflammation, including infection, is commonly associated with preterm labor. In this study, we identified the immunoproteasome subunit low-molecular-mass protein (LMP)7 mRNA expression to be significantly upregulated in laboring human myometrium. Silencing LMP7 using siRNA-targeted knockdown of LMP7 and its inhibitor ONX-0914 in human myometrial cells and tissues decreased proinflammatory cytokines (IL-6), cell chemotaxis (CXCL8, CCL2 expression, and THP-1 migration), cell to cell adhesion (ICAM1 expression and myometrial adhesion), contraction-associated proteins (PTGS2, FP, PGE2, and PGF2α), as well as suppressing contractions in myometrial cells and in myometrial tissues obtained from laboring women. In addition, LMP7 silencing reduced NF-κB RelA activity. ONX-0914 alleviated inflammation (CCL3, CXCL1, PTGS2, and IL-6) in myometrium, placenta, fetal brain, amniotic fluid, and maternal serum induced by LPS in pregnant mice. Collectively, our data suggest a novel role for ONX-014 to suppress uterine activation and contractility associated with preterm labor.

Bromodomain protein BRD4 is increased in human placentas from women with early-onset preeclampsia.

Preeclampsia affects 5% of all pregnancies and is a serious disorder of pregnancy, characterised by high maternal blood pressure, placental hypoxia, fluid retention (oedema) and proteinuria. Women with preeclampsia are associated with exaggerated levels of pro-inflammatory cytokines, chemokines and anti-angiogenic factors such as soluble fms-like tyrosine kinase-1 (sFLT1). Studies in non-gestational tissues have described the bromodomain (BRD) and extraterminal family of proteins, in particular BRD4 to play a critical role in propagating inflammation and is currently a therapeutic target for treating cancer, lung inflammation and asthma. The aims of this study were to: (i) determine the effect of severe early-onset preeclampsia on placental BRD4 expression; (ii) the effect of loss of BRD4 function by siRNA-targeted knockdown or with the BRD inhibitor JQ1 in human primary trophoblast cells and human umbilical vein endothelial cells (HUVECs) on TNF-stimulated production of pro-inflammatory mediators, cell adhesion molecules and anti-angiogenic markers and (iii) the effect of BRD4 suppression on placental sFLT1 secretion under hypoxia conditions and in preeclampic placenta. BRD4 mRNA expression was significantly increased (sevenfold) in severe early-onset preeclampsia placenta. BRD4 silencing resulted in a significant reduction in TNF-induced IL6, CXCL8, CCL2, CXCL1 and sFLT1-e15a mRNA expression and IL6, CXCL8, CCL2, CXCL1 and sFLT1 secretion in primary trophoblast and HUVECs. Additionally, JQ1 treatment significantly reduced placental sFLT1 secretion under hypoxic conditions and in preterm preeclamptic placenta. In conclusion, these findings suggest BRD4 may play a central role in propagating inflammation and endothelial dysfunction associated with the pathophysiology of early-onset preeclampsia.

Placental Pim-1 expression is increased in obesity and regulates cytokine- and toll-like receptor-mediated inflammation.

INTRODUCTION: Obesity is a growing epidemic, and as a consequence the number of obese pregnancies has also increased. Pregnancy is characterised by maternal and placental inflammation which is intensified with maternal obesity. The proviral integration site for Moloney murine leukemic virus (Pim)-1 protein is a serine/threonine kinase involved in a wide range of inflammatory diseases. In relation to obesity, however, its role has not been elucidated in human placenta. The aims were to determine the placental expression of Pim-1 with pre-existing maternal obesity and its role in regulating placental inflammation associated with obesity. METHODS: Human placenta was obtained at the time of term Caesarean section from lean and pre-existing obese pregnant women to determine the effect of maternal obesity on Pim-1 expression. To determine the effect of Pim-1 on the inflammatory response induced by bacterial endotoxin LPS and pro-inflammatory cytokines TNF-α or IL-1ß, the chemical inhibitor SMI-4a and siRNA were used. RESULTS: Pim-1 protein and mRNA expression was significantly increased in placenta of obese women. SMI-4a significantly suppressed the expression and release of pro-inflammatory cytokine IL-6 and chemokines GRO-α and MCP-1 when stimulated with LPS or TNF-α in placenta. Primary trophoblast cells transfected with Pim-1 siRNA had decreased expression and release of pro-inflammatory cytokines IL-1ß, IL-6, chemokines GRO-α and MCP-1, when stimulated with LPS, TNF-α or IL-1ß. DISCUSSION: The findings from this study implicate Pim-1 may contribute to placental inflammation in pregnancies complicated by maternal obesity. Thus, therapeutic targets for Pim-1 may improve fetal outcomes complicated by obese pregnancies.

Lipopolysaccharide and double stranded viral RNA mediate insulin resistance and increase system a amino acid transport in human trophoblast cells in vitro.

INTRODUCTION: Inflammation and underlying low-grade maternal infection can impair insulin signalling and upregulate nutrient transport in the placenta which contribute to fetal overgrowth associated with GDM and/or obese pregnancies. There are, however, no studies on the role of infection on placental nutrient transport in pregnancies complicated by GDM and/or obesity. Thus, the aims of this study were to determine the effect of the bacterial product lipopolysaccharide (LPS) or the viral dsRNA analogue polyinosinic:polycytidylic acid (poly(I:C)) on the insulin signalling pathway and amino acid transport in primary human trophoblast cells. METHODS: Human primary villous trophoblast cells were treated with LPS or poly(I:C). Protein expression of insulin signalling pathway proteins, insulin receptor (IR)-ß, insulin receptor substrate (IRS)-1 and protein kinase B (also known as Akt), and phosphatidylinositol-4,5-bisphosphate 3-kinase p85α subunit (PI3K-p85α) protein were assessed by Western blotting. Glucose and amino acid uptake were assessed by radiolabelled assay. Western blotting and qRT-PCR were used to determine amino acid transporter protein and mRNA expression, respectively. RESULTS: LPS and poly(I:C) significantly decreased phosphorylation of IR-ß, IRS-1, Akt, total PI3K-p85α protein expression and glucose uptake. LPS and poly(I:C) also significantly increased expression of System A amino acid transporters SNAT1 and SNAT2, and System A-mediated uptake of amino acids. DISCUSSION: LPS and poly(I:C) induces insulin resistance and increases amino acid uptake in human primary trophoblast cells. This suggests that the presence of low-grade maternal infection can contribute to excess placental nutrient availability and promote fetal overgrowth in pregnancies complicated by GDM and/or obesity.

Endocan expression is increased in the placenta from obese women with gestational diabetes mellitus.

INTRODUCTION: Endocan, a member of the proteoglycan family, is involved in a wide range of diseases including obesity and diabetes. The aim of this study was to determine the effect of (i) maternal obesity and gestational diabetes mellitus (GDM) on placental endocan expression; and (ii) endocan knockdown on markers of inflammation. METHODS: Endocan mRNA and protein expression was determined in human placenta from (i) lean and obese and normal glucose tolerant (NGT) pregnant women (n = 10 patients per group); and (ii) women with GDM and BMI-matched NGT women (n = 40 patients per group). Primary villous trophoblast cells and HUVECs were used to assess the effect of endocan siRNA knockdown on pro-inflammatory cytokines. RESULTS: There was no effect of maternal obesity on placental endocan expression. Further, endocan expression was not different between lean NGT and BMI-matched women with GDM. However, endocan mRNA and protein expression was significantly higher in placenta from obese women with GDM when compared to BMI-matched NGT women. Knockdown of endocan in villous trophoblast cells and HUVECs had no effect on infection- or inflammation-induced expression and secretion of IL-6, IL-8 and MCP-1. DISCUSSION: Endocan expression is increased in the human placenta from obese women with GDM, and in response to pro-inflammatory stimuli. Loss-of-function studies in villous trophoblast cells and HUVECs revealed that endocan is not directly involved in the genesis or in the expression of pro-inflammatory cytokines induced by LPS or IL-1ß. Further studies are required to elucidate the functional consequences of increased placental endocan expression in obese GDM pregnancies.

Activation of AMPK improves inflammation and insulin resistance in adipose tissue and skeletal muscle from pregnant women.

Gestational diabetes mellitus (GDM) is characterised by maternal peripheral insulin resistance and inflammation. Sterile inflammation and bacterial infection are key mediators of this enhanced inflammatory response. Adenosine monophosphate (AMP)-activated kinase (AMPK), which is decreased in insulin resistant states, possesses potent pro-inflammatory actions. There are, however, no studies on the role of AMPK in pregnancies complicated by GDM. Thus, the aims of this study were (i) to compare the expression of AMPK in adipose tissue and skeletal muscle from women with GDM and normal glucose-tolerant (NGT) pregnant women; and (ii) to investigate the effect of AMPK activation on inflammation and insulin resistance induced by the bacterial endotoxin lipopolysaccharide (LPS) and the pro-inflammatory cytokine IL-1ß. When compared to NGT pregnant women, AMPKα activity was significantly lower in women with GDM as evidenced by a decrease in threonine phosphorylation of AMPKα. Activation of AMPK, using two pharmacologically distinct compounds, AICAR or phenformin, significantly suppressed LPS- or IL-1ß-induced gene expression and secretion of pro-inflammatory cytokine IL-6, the chemokines IL-8 and MCP-1, and COX-2 and subsequent prostaglandin release from adipose tissue and skeletal muscle. In addition, activators of AMPK decreased skeletal muscle insulin resistance induced by LPS or IL-1ß as evidenced by increased insulin-stimulated phosphorylation of IRS-1, GLUT-4 expression and glucose uptake. These findings suggest that AMPK may play an important role in inflammation and insulin resistance.

Endoplasmic reticulum stress is increased in adipose tissue of women with gestational diabetes.

Maternal obesity and gestational diabetes mellitus (GDM) are two increasingly common and important obstetric complications that are associated with severe long-term health risks to mothers and babies. IL-1ß, which is increased in obese and GDM pregnancies, plays an important role in the pathophysiology of these two pregnancy complications. In non-pregnant tissues, endoplasmic (ER) stress is increased in diabetes and can induce IL-1ß via inflammasome activation. The aim of this study was to determine whether ER stress is increased in omental adipose tissue of women with GDM, and if ER stress can also upregulate inflammasome-dependent secretion of IL-1ß. ER stress markers IRE1α, GRP78 and XBP-1s were significantly increased in adipose tissue of obese compared to lean pregnant women. ER stress was also increased in adipose tissue of women with GDM compared to BMI-matched normal glucose tolerant (NGT) women. Thapsigargin, an ER stress activator, induced upregulated secretion of mature IL-1α and IL-1ß in human omental adipose tissue explants primed with bacterial endotoxin LPS, the viral dsRNA analogue poly(I:C) or the pro-inflammatory cytokine TNF-α. Inhibition of capase-1 with Ac-YVAD-CHO resulted in decreased IL-1α and IL-1ß secretion, whereas inhibition of pannexin-1 with carbenoxolone suppressed IL-1ß secretion only. Treatment with anti-diabetic drugs metformin and glibenclamide also reduced IL-1α and IL-1ß secretion in infection and cytokine-primed adipose tissue. In conclusion, this study has demonstrated ER stress to activate the inflammasome in pregnant adipose tissue. Therefore, increased ER stress may contribute towards the pathophysiology of obesity in pregnancy and GDM.

The Stress-responsive Heme Oxygenase (HO)-1 Isoenzyme is Increased in Labouring Myometrium where it Regulates Contraction-associated Proteins.

PROBLEM: Sterile inflammation through activation of cytokine receptor signalling pathways and viral or bacterial infection via activation of Toll-like receptors (TLRs) induces a cascade of events that leads to myometrial contractions and spontaneous preterm delivery. In non-pregnant tissues, heme oxygenase-1 (HO-1) is thought to play a central role in regulating the inflammatory response. Thus, the aims of this study were to determine the effect of human term labour on HO-1 expression in human myometrium and to investigate the role of HO-1 in myometrial primary cells in response to cytokine- and TLR ligand-induced inflammation. METHOD OF STUDY: Localization and expression of HO-1 protein in human myometrial tissues were determined using IHC. Western blot analysis and qRT-PCR were also used to determine HO-1 protein and gene expression, respectively, in human myometrium. siRNA knock-down of HO-1 in myometrial primary cells was used to determine its role in response to inflammatory stimuli. RESULTS: HO-1 gene expression and protein expression were increased in term labouring myometrium compared with non-labouring myometrium. Bacterial flagellin (TLR5 ligand), viral dsRNA analogue polyinosinic polycytidylic acid (poly(I:C)) (TLR3 ligand) and pro-inflammatory cytokines IL-1ß and TNF-α induced pro-inflammatory cytokine (IL-6 and IL-8) mRNA expression and release in myometrial cells. IL-1ß also induced COX-2 mRNA expression and prostaglandin release. HO-1 siRNA knock-down significantly decreased the expression and secretion of these prolabour mediators. Additionally, flagellin, poly(I:C), IL-1ß, and TNF-α-induced NF-κB transcriptional activity were suppressed in HO-1-deficient myometrial cells. CONCLUSION: Collectively, these findings in myometrium indicate HO-1 expression is increased with labour and exerts pro-inflammatory effects via NF-κB during cytokine- and TLR ligand-induced inflammation.

The macrophage galactose-type lectin can function as an attachment and entry receptor for influenza virus.

Specific protein receptors that mediate internalization and entry of influenza A virus (IAV) have not been identified for any cell type. Sialic acid (SIA), the primary attachment factor for IAV hemagglutinin, is expressed by numerous cell surface glycoproteins and glycolipids, confounding efforts to identify specific receptors involved in virus infection. Lec1 Chinese hamster ovary (CHO) epithelial cells express cell surface SIA and bind IAV yet are largely resistant to infection. Here, we demonstrate that expression of the murine macrophage galactose-type lectin 1 (MGL1) by Lec1 cells enhanced Ca(2+)-dependent IAV binding and restored permissivity to infection. Lec1 cells expressing MGL1 were infected in the presence or absence of cell surface SIA, indicating that MGL1 can act as a primary receptor or as a coreceptor with SIA. Lec1 cells expressing endocytosis-deficient MGL1 mediated Ca(2+)-dependent IAV binding but were less sensitive to IAV infection, indicating that direct internalization via MGL1 can result in cellular infection. Together, these studies identify MGL1 as a cell surface glycoprotein that can act as an authentic receptor for both attachment and infectious entry of IAV.

Proteomic analysis of human cervicovaginal fluid collected before preterm premature rupture of the fetal membranes.

A significant obstetric complication facing contemporary materno-fetal medicine is preterm premature rupture of the fetal membranes (preterm PROM), which occurs in 30% of all preterm births. The objective of this study was to identify differentially expressed proteins in the cervicovaginal fluid of asymptomatic women before the clinical manifestation of preterm PROM. The preterm PROM group comprised of women with samples collected 6-23 days before PROM, who subsequently delivered preterm (n=5). Women who spontaneously delivered at term served as gestation-matched controls (n=10). Two-dimensional difference in-gel electrophoresis was used to distinguish differential expression between the pooled groups and fold changes were subsequently confirmed by two-dimensional PAGE of individual samples. Spots of interest were identified by mass spectrometry. Proteins that were significantly reduced with impending preterm PROM included the following: thioredoxin (2.7-fold), interleukin 1 receptor antagonist (1.7-fold), fatty acid-binding protein 5 (2.1-fold), cystatin A (dimer; 1.9-fold), monocyte/neutrophil elastase inhibitor (1.6-fold), squamous cell carcinoma antigen-1 (2.1-fold) and γ-glutamyl cyclotransferase (3.0-fold). By contrast, annexin A3 (3.7-fold) and vitamin D binding protein (3.9-fold) were significantly increased with impending preterm PROM. Western blot analysis was also performed on an independent cohort of preterm PROM and control samples to validate these candidate biomarkers. These proteins have known biological functions in oxidative balance, anti-inflammatory activity, metabolism or protease inhibition that may facilitate membrane rupture.