Predominant contribution of IFN-beta expression to apoptosis induction in human uterine cervical fibroblast cells by influenza-virus infection

Identification of SMAD3 as a Novel Mediator of Inflammation in Human Myometrium In Vitro

Preterm birth remains the primary cause of early neonatal death and is a major determinant for long-term health consequences. Aberrant intrauterine inflammation and infection are known to augment the synthesis of proinflammatory cytokines and induce uterine contractions, which can subsequently lead to preterm birth. The transforming growth factor-β (TGF-β) superfamily members regulate numerous cellular processes through the activation of intracellular mediators known as mothers against decapentaplegic homolog (SMADs). Studies in nongestational tissues have shown that SMAD3 plays a role in immune regulation and inflammation; however, its role in human labour remains unknown. Thus, the present study aimed at (i) characterising the expression of SMAD3 in the human myometrium; (ii) determining the effect of bacterial and viral products and proinflammatory cytokines on SMAD3 transcriptional activity in primary human myometrial cells; and (iii) investigating the effect of SMAD3 siRNA knockdown on the production of prolabour mediators in primary human myometrial cells. Phosphorylated (i.e., active) SMAD3 protein expression was lower in the myometrium after spontaneous term labour compared to the myometrium from nonlabouring women. Using a luciferase assay, the proinflammatory cytokines IL-1β and TNF, and viral analogue polyinosinic : polycytidylic acid (poly(I : C)) significantly reduced SMAD3 transcriptional activity in human primary myometrial cells. Loss-of-function studies found that SMAD3 knockdown in myometrial cells significantly increased IL-1β- and poly(I : C)-induced proinflammatory cytokines (IL-1A, IL-6), chemokines (IL-8, MCP-1), the adhesion molecule ICAM-1, COX-2 mRNA expression, and subsequent PGF2α release. In conclusion, SMAD3 deficiency is associated with increased production of proinflammatory and prolabour mediators in the human myometrium.

N-acetyl cysteine reverses bio-behavioural changes induced by prenatal inflammation, adolescent methamphetamine exposure and combined challenges

RATIONALE

Schizophrenia is associated with prenatal inflammation and/or postnatal stressors such as drug abuse, resulting in immune-redox dysfunction. Antioxidants may offer therapeutic benefits.

OBJECTIVES

The objective of this study is to investigate N-acetyl cysteine (NAC) as a therapeutic antioxidant to reverse schizophrenia-like bio-behavioural changes in rats exposed to maternal immune activation (MIA), adolescent methamphetamine (MA) or a combination thereof.

METHODS

Sprague-Dawley offspring prenatally exposed to saline/lipopolysaccharide (LPS) received saline or MA (0.2-6 mg kg^-1 twice daily × 16 days) during adolescence and divided into LPS, MA and LPS + MA groups. Vehicle/NAC (150 mg kg^-1 × 14 days) was administered following MA/saline exposure on postnatal day 51-64. Social interaction, novel object recognition and prepulse inhibition (PPI) of startle, as well as regional brain monoamines, lipid peroxidation, plasma reactive oxygen species (ROS) and pro- and anti-inflammatory cytokines (TNF-α; IL-10), were assessed.

RESULTS

NAC reversed LPS, MA and LPS + MA-induced anxiety-like social withdrawal behaviours, as well as MA and LPS + MA-induced deficits in recognition memory. PPI deficits were evident in MA, LPS and LPS + MA models, with NAC reversing that following LPS + MA. NAC reversed LPS, MA and LPS + MA-induced frontal cortical dopamine (DA) and noradrenaline (NA) elevations, LPS and LPS + MA-induced frontal cortical 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT) and striatal NA deficits as well as LPS + MA-induced frontal cortical 5-HT turnover. Decreased IL-10 in the LPS, MA and LPS + MA animals, and increased TNF-α in the LPS and MA animals, was reversed with NAC. NAC also reversed elevated lipid peroxidation and ROS in the LPS and LPS + MA animals.

CONCLUSIONS

Prenatal LPS, LPS + postnatal MA challenge during adolescence, and to a lesser extent MA alone, promotes schizophrenia-like bio-behavioural changes later in life that are reversed by NAC, emphasizing therapeutic potential for schizophrenia and MA-associated psychosis. The nature and timing of the dual-hit are critical.

Hepatitis A virus cellular receptor 2 (HAVCR2) is decreased with viral infection and regulates pro-labour mediators OA

PROBLEM

Intrauterine infection caused by viral infection has been implicated to contribute to preterm birth. Hepatitis A virus cellular receptor 2 (HAVCR2) regulates inflammation in non-gestational tissues in response to viral infection.

METHOD OF STUDY

The aims of this study were to determine the effect of: (i) viral dsRNA analogue polyinosinic:polycytidylic acid (poly(I:C)) on HAVCR2 expression; and (ii) HAVCR2 silencing by siRNA (siHAVCR2) in primary amnion and myometrial cells on poly(I:C)-induced inflammation.

RESULTS

In human foetal membranes and myometrium, HAVCR2 mRNA and protein expression was decreased when exposed to poly(I:C). Treatment of primary amnion and myometrial cells with poly(I:C) significantly increased the expression and release of pro-inflammatory cytokines TNF, IL1A, IL1B and IL6; the expression of chemokines CXCL8 and CCL2; the expression and secretion of adhesion molecules ICAM1 and VCAM1; and PTGS2 and PTGFR mRNA expression and the release of prostaglandin PGF_2α . This increase was significantly augmented in cells transfected with siHAVCR2. Furthermore, mRNA expression of anti-inflammatory cytokines IL4 and IL10 was significantly decreased.

CONCLUSION

Collectively, our data suggest that HAVCR2 regulates cytokines, chemokines, prostaglandins and cell adhesion molecules in the presence of viral infection. This suggests a potential for HAVCR2 activators as therapeutics for the management of preterm birth associated with viral infections.

Regulation of kynurenine biosynthesis during influenza virus infection

Influenza A viruses (IAVs) remain serious threats to public health because of the shortage of effective means of control. Developing more effective virus control modalities requires better understanding of virus-host interactions. It has previously been shown that IAV induces the production of kynurenine, which suppresses T-cell responses, enhances pain hypersensitivity and disturbs behaviour in infected animals. However, the regulation of kynurenine biosynthesis during IAV infection remains elusive. Here we showed that IAV infection induced expression of interferons (IFNs), which upregulated production of indoleamine-2,3-dioxygenase (IDO1), which catalysed the kynurenine biosynthesis. Furthermore, IAV attenuated the IDO1 expression and the production of kynurenine through its NS1 protein. Interestingly, inhibition of viral replication prior to IFN induction limited IDO1 expression, while inhibition after did not. Finally, we showed that kynurenine biosynthesis was activated in macrophages in response to other stimuli, such as influenza B virus, herpes simplex virus 1 and 2 as well as bacterial lipopolysaccharides. Thus, the tight regulation of the kynurenine biosynthesis by host cell and, perhaps, pathogen might be a basic signature of a wide range of host-pathogen interactions, which should be taken into account during development of novel antiviral and antibacterial drugs.

Virus-Infected Human Mast Cells Enhance Natural Killer Cell Functions

Mucosal surfaces are protected from infection by both structural and sentinel cells, such as mast cells. The mast cell's role in antiviral responses is poorly understood; however, they selectively recruit natural killer (NK) cells following infection. Here, the ability of virus-infected mast cells to enhance NK cell functions was examined. Cord blood-derived human mast cells infected with reovirus (Reo-CBMC) and subsequent mast cell products were used for the stimulation of human NK cells. NK cells upregulated the CD69 molecule and cytotoxicity-related genes, and demonstrated increased cytotoxic activity in response to Reo-CBMC soluble products. NK cell interferon (IFN)-γ production was also promoted in the presence of interleukin (IL)-18. In vivo, SCID mice injected with Reo-CBMC in a subcutaneous Matrigel model, could recruit and activate murine NK cells, a property not shared by normal human fibroblasts. Soluble products of Reo-CBMC included IL-10, TNF, type I and type III IFNs. Blockade of the type I IFN receptor abrogated NK cell activation. Furthermore, reovirus-infected mast cells expressed multiple IFN-α subtypes not observed in reovirus-infected fibroblasts or epithelial cells. Our data define an important mast cell IFN response, not shared by structural cells, and a subsequent novel mast cell-NK cell immune axis in human antiviral host defense.

Involvement of GRIM-19 in apoptosis induced in H5N1 virus-infected human macrophages

The fatal H5N1 infection has a high mortality rate among infected patients. The pathogenesis of H5N1 viral infection is associated with the ability of the virus to induce apoptotic cell death. However, the molecular mechanism of apoptosis induced by H5N1 remains unclear. In the present study we demonstrate that H5N1 virus is able to up-regulate the expression of gene associated with retinoid and interferon induced mortality-19 (GRIM-19) in human monocyte-derived macrophages (hMDMs). GRIM-19 has been identified as a novel gene with apoptotic effects in virus-infected cells. The percentage of apoptotic cells is significantly decreased in H5N1-infected GRIM-19 depleted hMDMs, which is also associated with a decrease of BH3-interacting domain death agonist cleavage and apoptosis-inducing factor (AIF) release to the cytosol. These results suggested the involvement of GRIM-19 in apoptosis induced by H5N1 virus. Furthermore, neutralizing-IFN-β Ab is able to suppress GRIM-19 expression in H5N1-infected cells resulting in a decrease in apoptotic cell number, indicating that IFN-β secreted by H5N1-infected hMDMs regulates GRIM-19 expression leading to apoptosis. Altogether, the results presented here provide additional insight on the regulatory mechanism of H5N1 viral-induced apoptotic cell death in hMDMs.

Apoptosis induced by mammalian reovirus is beta interferon (IFN) independent and enhanced by IFN regulatory factor 3- and NF-κB-dependent expression of Noxa

A variety of signal transduction pathways are activated in response to viral infection, which dampen viral replication and transmission. These mechanisms involve both the induction of type I interferons (IFNs), which evoke an antiviral state, and the triggering of apoptosis. Mammalian orthoreoviruses are double-stranded RNA viruses that elicit apoptosis in vitro and in vivo. The transcription factors interferon regulatory factor 3 (IRF-3) and nuclear factor kappa light-chain enhancer of activated B cells (NF-κB) are required for the expression of IFN-β and the efficient induction of apoptosis in reovirus-infected cells. However, it is not known whether IFN-β induction is required for apoptosis, nor have the genes induced by IRF-3 and NF-κB that are responsible for apoptosis been identified. To determine whether IFN-β is required for reovirus-induced apoptosis, we used type I IFN receptor-deficient cells, IFN-specific antibodies, and recombinant IFN-β. We found that IFN synthesis and signaling are dispensable for the apoptosis of reovirus-infected cells. These results indicate that the apoptotic response following reovirus infection is mediated directly by genes responsive to IRF-3 and NF-κB. Noxa is a proapoptotic BH3-domain-only protein of the Bcl-2 family that requires IRF-3 and NF-κB for efficient expression. We found that Noxa is strongly induced at late times (36 to 48 h) following reovirus infection in a manner dependent on IRF-3 and NF-κB. The level of apoptosis induced by reovirus is significantly diminished in cells lacking Noxa, indicating a key prodeath function for this molecule during reovirus infection. These results suggest that prolonged innate immune response signaling induces apoptosis by eliciting Noxa expression in reovirus-infected cells.

Oxidative stress in schizophrenia: an integrated approach

Oxidative stress has been suggested to contribute to the pathophysiology of schizophrenia. In particular, oxidative damage to lipids, proteins, and DNA as observed in schizophrenia is known to impair cell viability and function, which may subsequently account for the deteriorating course of the illness. Currently available evidence points towards an alteration in the activities of enzymatic and nonenzymatic antioxidant systems in schizophrenia. In fact, experimental models have demonstrated that oxidative stress induces behavioral and molecular anomalies strikingly similar to those observed in schizophrenia. These findings suggest that oxidative stress is intimately linked to a variety of pathophysiological processes, such as inflammation, oligodendrocyte abnormalities, mitochondrial dysfunction, hypoactive N-methyl-d-aspartate receptors and the impairment of fast-spiking gamma-aminobutyric acid interneurons. Such self-sustaining mechanisms may progressively worsen producing the functional and structural consequences associated with schizophrenia. Recent clinical studies have shown antioxidant treatment to be effective in ameliorating schizophrenic symptoms. Hence, identifying viable therapeutic strategies to tackle oxidative stress and the resulting physiological disturbances provide an exciting opportunity for the treatment and ultimately prevention of schizophrenia.

Broad-spectrum drugs against viral agents

Development of antivirals has focused primarily on vaccines and on treatments for specific viral agents. Although effective, these approaches may be limited in situations where the etiologic agent is unknown or when the target virus has undergone mutation, recombination or reassortment. Augmentation of the innate immune response may be an effective alternative for disease amelioration. Nonspecific, broad-spectrum immune responses can be induced by double-stranded (ds)RNAs such as poly (ICLC), or oligonucleotides (ODNs) containing unmethylated deocycytidyl-deoxyguanosinyl (CpG) motifs. These may offer protection against various bacterial and viral pathogens regardless of their genetic makeup, zoonotic origin or drug resistance.

Secretion of bioactive interleukin-6 and tumor necrosis factor-alpha proteins from primary cultured human fetal membrane chorion cells infected with influenza virus

Influenza virus infection during pregnancy is implicated in one of the causes of premature delivery, abortion and stillbirth. Pro-inflammatory cytokines, such as interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha produced by fetal membranes, are postulated to facilitate premature delivery. We investigated the secretion of IL-6 and TNF-alpha from primary cultured human fetal membrane chorion and amnion cells infected with influenza virus at protein and bioactivity levels in order to understand the pathology of premature delivery during influenza virus infection. Concentrations of IL-6 and TNF-alpha proteins were significantly increased in culture supernatants of chorion cells by influenza virus infection. Culture supernatants of the virus-infected chorion cells stimulated the proliferation of IL-6-sensitive 7-TD-1 cells and induced the cytolysis of TNF-alpha-sensitive L929 cells, both activities of which were inhibited by the addition of respective antibody, whereas no such phenomena were observed in amnion cells. The results demonstrated that only chorion cells secreted significant amounts of bioactive IL-6 and TNF-alpha proteins responding to influenza virus infection. The present study suggests a possibility that the secretion of bioactive IL-6 and TNF-alpha proteins from fetal membrane chorion cells is implicated in the pathogenesis of premature delivery during influenza virus infection.