Advertisement
Browse Subject Areas
?

Click through the PLOS taxonomy to find articles in your field.

For more information about PLOS Subject Areas, click here.

  • Loading metrics

Hepatic Gene Expression Profile in Mice Perorally Infected with Echinococcus multilocularis Eggs

  • Bruno Gottstein ,

    bruno.gottstein@ipa.unibe.ch

    Affiliation Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland

  • Matthias Wittwer,

    Affiliation Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland

  • Marc Schild,

    Affiliation Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland

  • Michael Merli,

    Affiliation Department of Parasitology, University of Hohenheim, Stuttgart, Germany

  • Stephen L. Leib,

    Affiliation Faculty of Medicine, Institute for Infectious Diseases, University of Bern, Bern, Switzerland

  • Norbert Müller,

    Affiliation Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland

  • Joachim Müller,

    Affiliation Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland

  • Rolf Jaggi

    Affiliation Faculty of Medicine, Department of Clinical Research, University of Bern, Bern, Switzerland

Hepatic Gene Expression Profile in Mice Perorally Infected with Echinococcus multilocularis Eggs

  • Bruno Gottstein, 
  • Matthias Wittwer, 
  • Marc Schild, 
  • Michael Merli, 
  • Stephen L. Leib, 
  • Norbert Müller, 
  • Joachim Müller, 
  • Rolf Jaggi
PLOS
x

Abstract

Background

Alveolar echinococcosis (AE) is a severe chronic hepatic parasitic disease currently emerging in central and eastern Europe. Untreated AE presents a high mortality (>90%) due to a severe hepatic destruction as a result of parasitic metacestode proliferation which behaves like a malignant tumor. Despite this severe course and outcome of disease, the genetic program that regulates the host response leading to organ damage as a consequence of hepatic alveolar echinococcosis is largely unknown.

Methodology/Principal Findings

We used a mouse model of AE to assess gene expression profiles in the liver after establishment of a chronic disease status as a result of a primary peroral infection with eggs of the fox tapeworm Echinococcus multilocularis. Among 38 genes differentially regulated (false discovery rate adjusted p≤0.05), 35 genes were assigned to the functional gene ontology group <immune response>, while 3 associated with the functional group <intermediary metabolism>. Upregulated genes associated with <immune response> could be clustered into functional subgroups including <macrophages>, <APCs>, <lymphocytes, chemokines and regulation>, <B-cells> and <eosinophils>. Two downregulated genes related to <lymphocytes, chemokines and regulation> and <intermediary metabolism>, respectively. The <immune response> genes either associated with an <immunosupression> or an <immunostimulation> pathway. From the overexpressed genes, 18 genes were subsequently processed with a Custom Array microfluidic card system in order to assess respective expression status at the mRNA level relative to 5 reference genes (Gapdh, Est1, Rlp3, Mdh-1, Rpl37) selected upon a constitutive and stable expression level. The results generated by the two independent tools used for the assessment of gene expression, i.e., microarray and microfluidic card system, exhibited a high level of congruency (Spearman correlation rho = 0.81, p = 7.87e-5) and thus validated the applied methods.

Conclusions/Significance

Based on this set of biomarkers, new diagnostic targets have been made available to predict disease status and progression. These biomarkers may also offer new targets for immuno-therapeutic intervention.

Introduction

Alveolar echinococcosis (AE) is a result of a hepatic infection with the larval (metacestode) stage of the fox tapeworm Echinococcus multilocularis. AE as a disease is associated with high mortality (>90%) if remaining untreated [1]. AE patients are affected by hepatic sequelae that are due to a wide spectrum of liver injury leading predominantly to cholestatic jaundice (about a third of cases) and/or unspecific epigastric pain (about a third of cases), together with various symptoms such as fatigue, weight loss and hepatomegaly [2].

As a result of peroral infection via eggs of E. multilocularis, the parasitic metacestode (larval stage) subsequently grows as a tumor-like tissue in the liver of its intermediate host, include predominantly small rodents, but accidentally also humans. Thus, the laboratory mouse is an excellent model to study the host-parasite interplay. While most studies so far have been carried out upon so-called secondary infections (intraperitoneal inoculation of fully developed metacestode tissue), the respective difficulty lies in the fact that this infection model does not include primary hepatic events that are crucial to understand the natural host-parasite interplay. The real approach to determining the biological events in vivo is to carry out peroral inoculation of infectious E. multilocularis eggs, experiments that can only be performed in appropriate biosafety level 3 laboratory units. Such experimental infection is referred to as primary infection, resulting in an intrahepatic tumor-like growth of the metacestode that overcomes the immune system and subsequently establishes a chronic phase of infection, which persists approximately between 4–6 months p.i.. Through effects on cells of both the innate and adaptive arms of the immune response, the parasite can orchestrate a range of outcomes that are beneficial not only for metacestode establishment, but also in terms of facilitating its proliferation and maturation. In addition, the complex host-parasite interaction leads to only limited pathology. Likewise, a higher survival potential for both host and parasite is achieved.

Despite the severity of AE in humans, the genetic program that regulates the mechanisms leading to liver damage as a consequence of AE is largely unknown. High-throughput methods, e.g. DNA microarrays, can provide a comprehensive picture of the genes underlying the host responses to AE. This knowledge is a prerequisite for understanding the pathogenesis of liver damage and can drive the development of new prognostic and/or therapeutic modalities for AE. The aim of this study was to identify genes and sets of genes implicated in the immuno-pathophysiological mechanisms leading to the induction of a host response to infection, but subsequently also to hepatic damage observed in experimental AE. We used an appropriate mouse model of primary AE infection and DNA microarray technology to assess gene expression profiles in the periparasitic liver tissue known to be preferentially affected, in mock-infected controls and during the phase of early chronic AE following peroral infection of the mice with infectious E. multilocularis eggs (thus exactly mimicking the natural way of infection). Significantly overexpressed genes on microarrays were re-investigated and validated by real-time RT-PCR using microfluidic cards.

Results

Animal model

Eight to 10-week-old female BALB/c mice were purchased from Charles River GmbH, Germany. For all experiments, animals were matched for age and weight. All mice were housed and handled under standard aseptic animal laboratory conditions according to the rules of the Swiss regulations for animal experimentation. Maintenance of perorally E. multilocularis egg infected animals (see below) was carried out in a B3 safety containment, these experiments required governmental safety approval (Swiss Federal concession no. A990006/3A). Primary infections of mice were all based upon the use of a single batch of E. multilocularis eggs, obtained and purified as previously described [3]. The viability and infectivity rate of this batch of eggs had been predetermined by appropriate explorative titration-infection trials in mice [4]. For the present batch and experiments, primary infection parameters were 2,000 eggs per mouse to be administered perorally, yielding a medium number of 26 primary lesions per liver (range 12–35). Technically, intragastric E. multilocularis egg inoculation was performed as described elsewhere [5]. 31 days after infection, all infected animals (n = 8) had alveolar echinococcosis of the liver as evidenced by the presence of between 5 to 22 hepatic liver lesions, all exhibiting the same morphology including a central parasitic vesicle of approximately 1–2 mm of diameter, and surrounded by a white periparasitic inflammatory corona of about 0.5 mm in diameter. Mock-infected control animals presented neither macroscopically nor microscopically visible lesions in the liver.

Microarrays

Changes of the mouse hepatic gene expression in response to primary hepatic E. multilocularis infection were examined during the initial phase of chronic infection stage (i.e. after 1 month). The parasitized animals shared a total of 38 genes that significantly changed after 1 mon of infection (fdr adjusted P-value of <0.05) (Tab. 1). Of those genes, 36 appeared upregulated in reference to non-infected controls, and 2 yielded down-regulation.

thumbnail
Table 1. Probe-sets representing 38 genes, their expression levels in the liver, organized according to their functional groups.

https://doi.org/10.1371/journal.pone.0009779.t001

Microfluidic card system mRNA assessment

From the overexpressed genes, 18 genes were subsequently investigated with a TaqMan® Custom Array microfluidic card system in order to assess respective expression status at the mRNA level in reference to 5 reference genes (Gapdh, Est1, Rlp3, Mdh-1, Rpl37). In Table 2, up- and downregulation were calculated from real time data, genes were clustered according to the mode used for Table 1.

thumbnail
Table 2. TaqMan® Custom Array microfluidic card system was used to assess expression status at the mRNA level of 18 selected genes (see Table 1) in reference to 5 reference genes (Gapdh, Est1, Rlp3, Mdh-1, Rpl37).

https://doi.org/10.1371/journal.pone.0009779.t002

When comparing microarray and microfluidic card system, they exhibited a high level of congruency (Spearman correlation rho = 0.81, p = 7.87e-5).

Overview of differential gene regulation

Most (34 from 36, 94%) of upregulated genes were annotated to <defense and immune response> processes, while 2 genes (6%) were annotated to <intermediary metabolism> of hepatocytes. Upregulated genes associated with <immune response/defense> (n = 34) could be clustered into functional subgroups including <macrophages> (n = 15), <APCs> (n = 6), <lymphocytes, chemokines and regulation> (n = 10), <B-cells> (n = 2) and <eosinophils> (n = 1). Two downregulated genes related to <lymphocytes, chemokines and regulation> and <intermediary metabolism>, respectively (Tab. 1).

The <immune response> genes (n = 35) either associated with an <immunosupression> or an <immunostimulation> pathway, are schematically drawn in (Fig. 1).

thumbnail
Figure 1. Schematic hepatic cell type interaction profile linked to differentially expressed genes.

Interaction of cell types in mouse livers infected with E. multilocularis metacestodes as suggested by the pattern of differentially expressed genes (numbers in brackets) shown in Table 1. Interactions indicated by dashed arrows are hypothetical.

https://doi.org/10.1371/journal.pone.0009779.g001

In the following paragraph, first upregulated, then downregulated genes will be presented more in details:

Immune response/defense [MØ]; up-regulated

BC023105, Tgtp, Gvin1.

These belong to the interferon-inducible p47 GTPases. Interferons (with a preference IFN-γ over α/β) bind to their respective receptors. For Tgtp, the binding is followed by phosphorylation of STAT1 and rapid translocation of P-STAT1 dimers to the nucleus. There, the complex activates transcription of p47 GTPases by binding to the IFN-γ activation site (GAS) in the promoter. The gene products enable the MØ phagosome to be part of the innate defense of cells to infection, but its role in such defense has not yet been clearly defined [6].

GBPs (GBP1, GBP2, 5830443L24Rik, GBP8).

GBPs are upregulated in macrophages in response to IFN-γ. GBP-1 is a large GTPase that is induced by inflammatory cytokines and acts antiangiogenically through the inhibition of endothelial cell proliferation and migration [7]. Interestingly, some GBPs are upregulated in mice infected with intracellular pathogens such as L. monocytogenes and T. gondii and are colocalized with T. gondii in infected cells [8]. GBP-1 is also a marker of inflammation that may protect against epithelial apoptosis induced by inflammatory cytokines and subsequent loss of barrier function [9].

MARCO.

MØ express several host-defense receptors that can be divided into two classes; those dependent on opsonizing components for recognizing pathogens, and those that can recognize pathogens directly. MARCO belongs to a family of class A scavenger with pattern recognition receptors, some of which have been shown to bind lipopolysaccharide that are surface components of many infectious organisms [10]. It will be of upmost interest to search for E. multilocularis glycans such as Em492 for their interaction potential with MØ via MARCO.

STAT1.

STAT1 plays an important role in HA-mediated inflammatory processes [11]. It has been demonstrated that IL-27 controls the development of Th17 and iTreg cells via differential effects on STAT1 [12]. One of the main role of STAT1 is in activating GBP2 transcription to provide transcriptionally competent chromatin [13]. Activation of STAT1 attenuates liver fibrosis through inhibition of HSC proliferation, attenuation of TGF-beta signaling, and stimulation of NK cell killing of activated HSCs. STAT1 could be a new therapeutic target for treating alveolar echinococcosis, similar to that shown e.g. for liver fibrosis [14]. Analysis of T cell responses revealed that STAT1 was not required for the development of a Th1 response, but was required for the infection-induced up-regulation of T-bet. Moreover, Stat1 interacts with Mcm5 and thus may trigger IFN-dependent cell proliferation [15].

Mcm5 (CD46).

Mcm5 is a member of the MCM complex which is essential for the initiation of replication. Mcm5 is one of the nuclear proteins that inertact with phosphorylated STAT1 and therefore may play a role in JAK-STAT-modulated cell proliferation [15]. Like other replication factors, Mcm5 is considered as a marker for tumor proliferation, thus it will be interesting to study its putative role in promoting the unrestricted metacestode proliferation encountered in murine alveolar echinococcosis of the liver.

Il2rg (CD132), Pleckstrin, Lgals3.

Naive T cells can be induced to undergo homeostatic proliferation of variable speed with a few members of the common gamma-chain (CD132) family of cytokines [16]. The IL2 receptor γ chain interacts with insulin receptor substrate (IRS) proteins. These proteins have a pleckstrin binding domain and are phosphorylated partly by JAK-kinases [17]. Pleckstrin is involved in intracellular signaling, e.g. by PI3K pathways that participate in IL-signalling [17], insulin signaling and inflammatory responses [18]. Galectin-3 is a 30 kDa lectin binding β-galactoside expressed and secreted by macrophages. It is a chemoattractant for monocytes and macrophages. CD98 is the receptor for galectin on the macrophage membrane and triggers macrophage activation by the PI3K-pathway. Both components are involved in alternative macrophage activation by IL-4 since disruption of the galectin gene in mice restrains macrophage activation [19].

Clec7a.

The c-type lectin 7a (Dectin-1) is expressed on monocytes, macrophages, and dendritic cells as a phagocytic receptor for β-glucan containing particles. Dectin-1 collaborates with toll-like receptor 2 in inflammatory responses against microbial pathogens [20].

Serpina3g.

Serpin3g is a cytoplasmic inhibitor of papain-like, and is required for the protection of cells from caspase-independent PCD triggered by tumor necrosis factor-alpha. In the absence of caspase activity, Spi2A suppressed PCD by inhibiting cathepsin B after it was released into the cytoplasm. Spi2A also directly protects against ROS-mediated PCD, which is consistent with a role in suppressing caspase-independent pathways of PCD. Inhibition of lysosomal executioner proteases by Spi2A is a physiological mechanism by which cells are protected from caspase-independent programmed cell death [21].

Immune response/defense [APC]; up-regulated

H2-Ab1, H2-Eb1, H2-aa, H2-Dma, H2-DMb1.

Activation of naive CD4 T cells by dendritic cells requires the sequential interaction of many TCR molecules with peptide-class II complexes of the appropriate specificity. Such interaction results in morphological transformation of class II MHC-containing endosomal compartments. It is generally accepted that MHC II alleles may influence T-cell functions by restricting TCR access to specific residues of the I-A-bound peptide. Thus, this is of significance to diseases that display genetic linkage to specific MHC II alleles, which, however, has not yet been demonstrated for neither murine nor human alveolar echinococcosis.

CD74.

Dendritic cells (DCs) sample peripheral tissues of the body in search of antigens to present to T cells. This requires two processes, antigen processing and cell motility, originally thought to occur independently. The major histocompatibility complex II-associated invariant chain (Ii or CD74), a known regulator of antigen processing, negatively regulates DC motility in vivo [22].

Immune response/defense [Lymphocytes, chemokines and regulation]; up-regulated

CXCL9, CXCL10.

CXCL9 is a proinflammatory monokine, induced by interferon-gamma, which supports Th1-cell mediated tissue inflammation [23]. CXCL10 regulates liver innate immune response [24], its role in alveolar echinococcosis is still unknown. It is generally accepted to potentiate the gene expression of iNOS and CXC chemokine ligand 10 (CXCL10), a major chemoattractant of T helper cell type 1 [25]. This protein is also expressed as a marker of hepatic inflammation and injury, suggesting a role in liver repair and regeneration [26].

CCL5 (RANTES).

CCL5 expression correlates with resistance, and blockade of CCL5 rendered mice more susceptible to infection. CCL5 is part of the cascade of events leading to efficient parasite control such as in L. major infection. CCL5 up-regulates IL-12, IFN-gamma, and migration of Th1 cells, particularly memory T cells [27].

Ms4a4b.

MS4a4B was reported to be expressed in Th1-cells but not Th2-cells. Overexpression of MS4a4B in primary CD4+ T-cell blasts enhanced T-cell receptor (TCR)-induced Th1 cytokine production. This suggested that MS4a4B expression is tightly regulated during T-cell development and that MS4a4B expression promotes Th1 function and/or differentiation [28].

Cdkn1a (P21).

P21 plays an essential role in determining the type of cell death, positively for apoptosis and negatively for autophagy [29]. Genetic inactivation of p21 in JNK1−/− mice restored hepatocyte proliferation in models of both liver carcinogenesis and liver regeneration, and overexpression of c-Myc increased proliferation of JNK1−/− liver cells. Pharmacologic inhibition of JNK reduced the growth of both xenografted human HCC cells and chemically induced mouse liver cancers. These findings provide a mechanistic link between JNK activity and liver cell proliferation via p21 and c-Myc and suggest JNK targeting can be considered as a new therapeutic approach for HCC treatment. [30].

Ifi205.

Ifi205 belongs to the class of interferon inducible p200 proteins that regulate cell proliferation. Ifi205 has been shown to upregulate the cell cycle inhibitor P21 by interacting with p53 [31].

Ly86 (MD1).

Ly86 contributed to LPS-induced B-cell proliferation, antibody production, and B7.2/CD86 up-regulation [32].

FGL2.

FGL2 inhibits dendritic cell maturation and induces apoptosis of B cells through binding to the low-affinity FcgammaRIIB receptor, and thus contributes to Treg cell activity [33]. There is evidence FGL2 exerts immunosuppressive effects on T cell proliferation and DC maturation [34].

VCAM-1.

Vascular cell adhesion molecule-1 (VCAM-1) mediates cell adhesion and transendothelial migration of leukocytes. These molecules do not play a direct role in the recruitment of leukocytes to the infected liver, but instead contribute to IL-12p40-production by splenic CD8(+) dendritic cells (DC). This can be associated with reduced anti-parasitic CD4(+) T cell activation in the spleen and lowered hepatic IFN-gamma, TNF and nitric oxide production. Such effects can be associated with enhanced parasite growth in the liver [35].

Rgs2 (29).

Rgs (regulator of G protein signaling) proteins have been characterized as inhibitors of signal transduction cascades initiated by G-protein coupled receptors. Rgs2 is widely expressed in mouse and human tissues. Knock-down studies have shown that Rgs2 is important for T-cell-proliferation and interleukin production [36].

Immune response/defense [eosinophils]; up-regulated

Ear2 (EDN).

Based on its ability to serve as a chemoattractant and activator of DCs, as well as the capacity to enhance antigen-specific immune responses, Ear2 (eosinophil-associated ribonuclease 4) is considered to have the properties of an endogenous alarmin that alerts the adaptive immune system for preferential enhancement of antigen-specific Th2 immune responses [37]. Furthermore, anti-microbial actiovities have been documented by Nakajima et al. [38]. Mouse EAR2, is also chemotactic for human as well as mouse DCs [39].

Intermediary metabolism [hepatocytes]; up-regulated

Lpl.

Lipoprotein lipase (Lpl) binds to lipoproteins and specific cell surface proteins in a non-catalytic way. Lpl is expressed in a tissue-specific pattern during development with an increase in adipose tissue, but a decrease in liver. Interestingly, Lpl is also expressed in macrophages where interleukins and interferons downregulate and free fatty acids upregulate expression [40]. Conclusively, an increase would suggest the differentiation of adipocytes in the infected liver.

Hk3.

Hexokinase III has a very high affinity for glucose, is inhibited by glucose at higher concentrations. Given the specific catalytic patterns, hexokinase III is most likely involved in anabolic processes, e.g. lipid biosynthesis, by providing NADPH by the pentose phosphate pathway [41].

Immune response/defense [Lymphocytes, chemokines and regulation]; down-regulated

Pim3.

Pim3 is expressed at low levels in the liver, but upregulated in malignant liver tissue [42]. Pim 3 phosphorylates and thus inactivates the pro-apoptotic protein Bad. The active Bad protein binds to anti-apoptotic proteins of the Bcl2 family thus allowing induction. By phosphorylation of Bad, binding sites for 14-3-3-protein are created. The resulting Bad-14-3-3-complex is no longer able to interfere with Bcl2 proteins thus preventing cell death [43].

Intermediary metabolism [hepatocytes]; down-regulated

Crotonase homologous.

Crotonase (Enoyl-coenzyme-A-hydratase) catalyses the hydratation of trans-2-enoyl-CoA thioesters resulting from the first step of beta-oxidation of fatty acids [44].

Discussion

Functional analysis, immunostimulatory pathway

The involvement of cellular immunity in controlling the infection is strongly suggested by the intense granulomatous infiltration observed in the periparasitic area of lesions in experimentally infected mice [45], [46]. Immunodeficient athymic nude [47] and SCID mice [48] as well as HIV-co-infected patients [49], [50] exhibited high susceptibility to infection and disease, thus suggesting that the host cell mediated immune response plays an important role in suppressing the larval growth. E. multilocularis appears to induce skewed Th2-responses [46]. Based on in vitro and in vivo studies, Th2-dominated immunity was associated with increased susceptibility to disease, while Th1 cell activation through IL-12 [46], IFNγ [51], [52], TNFα [53] and IFNα [54] was suggested to induce protective immunity in AE [55], [56]. Innate mechanisms appeared also to resistance upon attack by cytotoxic compounds such as activated complement proteins and NO, associated to increased macrophage activities [57], [58]. With regard to the hepatic gene expression profiles of our study related to immunostimulatory pathways (thus potentially also to efficient host control mechanisms), most of the highest expressed molecules (BC023105, Tgtp, Gvin1, GBPs, Clec7a) appear to localize within cytokine pathways involved in direct or indirect MØ activities. Respective parasite cell damage may be one option, but also subsequent antigen processing (MARCO: carbohydrates? Ly86: LPS-like antigens?) and orchestration of the subsequent T cell orientation (STAT1, Mcm5, Il2rg, Pleckstrin, Lgals3). Beside MØ, dendritic cells may intrahepatically contribute to the immunological response and defense, as indicated by hyperexpressed partner cell (e.g. CD4 T cells) molecules such as H2-Ab1, H2-Eb1, H2-aa, H2-Dma, H2-DMb1, CD74 and CCL5, all associated to CD4 T cell activation and action, especially Th1 (CCL5, Ms4a4b, Rgs2). That all these events are accompanied by periparasitic inflammatory processes are supported by overexpressed CXCL9, CXCL10. Finally, another hyperexpressed molecule (Serpina3g) may synergistically contribute to parasitocidal host effector mechanisms by controlling immunopathological events related to apoptotic tissue damage, putatively triggered by Cdkn1a, and downregulated Pim3 may contribute to such a phenomenon as well.

To carry out a more profound interpretation of the present findings, we have to take into account that the time point of investigation (infection status) corresponds to a rather early stage, not yet switched into the late/chronic stage of AE. Globally, the above listed phenomena correspond mostly to a still Th1-oriented immune response, which may putatively be the correct way to control infection. We know, however, that the parasite survives in the host. By inducing functional changes in DCs and MØs, the metacestode can achieve important shifts in T-cell subsets. The initial acute inflammatory Th1 response is subverted gradually to a Th2 response during the chronic phase of AE [59]. Cytokines, such as IL-4, IL-5, IL-9 and IL-13, secreted largely by immune-cell types in response to parasite antigens, not only down-modulate the Th1 response but can also promote parasite expulsion and tissue renewal and repair [60]. The metacestode most likely achieves the late infection stage Th2 expansion through the induction of regulatory cytokines, such as IL-10 and TGF-β [59]. To provide a platform of understanding the late stage event, we will have to prompt a more detailed investigation by using late stage infection mice. The question will arise as to whether it will be possible to obtain appropriate hepatic tissue free of metacestode material (a prerequisite in the present study), as at the advanced/late stage, usually the whole liver is metastatically interspersed with parasite cells/vesicles. One of the key questions remaining is how during the infection course the initial Th1-orientation switches to a rather Th2-oriented pathway. Our interest will thus focus on unraveling the metacestode tools (metabolites) that could trigger such a re-orientation.

Functional analysis, immunosuppressive pathway

An interesting feature observed in chronic AE is a marked depression of the cell-mediated immune response [61], [62], [63]. These general characteristics of E. multilocularis, including the seemingly tumor like growth, its ability to modulate host immune responses, and the fact that in vitro culture is an established technique, renders this parasite a very attractive model to study the host-parasite interplay in view to reveal potentially novel modes of therapy [56]. Increased concentrations of the pro-inflammatory cytokines TNF-a, IL-1b, iNOS and the anti-inflammatory IL-I0 are characteristic for secondary AE in mice [58].

With regard to the hepatic gene expression profiles of our study related to immunosuppressive pathways (thus potentially also to the support of parasite survival capacities), overexpressed molecules such as FGL2 can already interfere at early innate stage by inhibiting dendritic cell maturation, or by reducing T cell activation (VCAM-1). Such effects can be associated with enhanced parasite growth in the liver [64]. Interestingly, like in many other helminthic infections, the host immune response seems to make use of a rather Th2-dependent eosinophilic component to trigger its fight against the infectious agent (Ear2, EDN). The mobilization of eosinophils is known to be a crucial immunological event that plays an important role in the host defense against helminths. Despite appropriate host signals, there is a marked lack of eosinophilic infiltrates in experimental murine AE [59]. One possible explanation was recently provided by the demonstration that E. multilocularis metabolites exhibit proteolytic activity on eotaxin in vitro [58]. Inhibition of eotaxin activity may suppress the mobilization of eosinophils in E. multilocularis-infected mice. Absent eosinophils thus may be a part of a series of events that maintain a low level of inflammation in E. multilocularis-infected hosts.

Hepato-pathogenesis

The pathogenesis of liver damage in AE arises from the interplay of the parasitic metacestode and the host inflammatory response. It is generally accepted that the release of parasitic products/metabolites (such as cysteine proteases [59]) into the periparasitic hepatic tissue triggers the inflammatory response in the liver parenchyma by inducing the production and release of inflammatory cytokines, chemokines and lipid inflammatory mediators [59]. At an early stage of infection, little liver damage is observed [65]. That may be the reason why our study yielded few deregulated genes related to hepatocyte functions. The upregulation of a lipoprotein lipase and a hexokinase most likely involved in anabolism and the downregulation of crotonase are indications for a metabolic reprogramming of hepatocytes (Fig. 1) in the direction of fat accumulation (differentiation of adipocytes). Recently, an apolipoprotein binding protein from E. multilocularis hydatid fluid has been characterized [66]. These findings indicate the parasite may act as a sink for host lipids and stimulates lipid accumulation in vicinal host tissue. It is, however, unclear whether E. multilocularis is able to use lipids as a source for carbon and energy. Although it is clear that glycolysis and tricarboxylic acid cycle are functional (yielding succinate under anaerobic conditions), results concerning lipid catabolism via beta-oxidation are lacking [67]. Host lipids may also be attracted and exposed as a part of a strategy to circumvent the host immune system. In any case, these proteins could be interesting targets to address in future studies, presently these molecules remain still at a speculative level and are difficult to discuss without further pathological characteristics related to these molecules. At a late stage of infection, fibrosis becomes a hallmark of AE, leading to a complete disappearance of the liver parenchyma and even to the death of the metacestode, with vesicles embedded in an acellular tissue composed nearly entirely of cross-linked collagens [68]. The diffusion of the fibrotic process even far from the parasitic lesions strongly suggests a major role for cytokines in collagen synthesis. But these features could not be addressed and thus also not discussed in the present study. As mentioned above, we will design new studies respecting temporal aspects to unravel late stage characteristics of murine AE.

Conclusion

The conventional course of AE as a disease in humans resembles strongly that of the naturally infected mouse, in that untreated AE will, in many but not most cases, finally lead to fatality.

In order to better understand periparasitic events characterizing the host response to infection, we assessed the gene expression profile in the periparasitic liver tissue during early chronic AE. High throughput analysis of gene expression yielded a set of mostly immunologically related upregulated genes, while downregulation almost exclusively lacked. The data presented herein may provide a road map for further investigations into the pathophysiology of AE and may help to identify potential targets for adjuvant therapy of this disease. Future interest will also focus on unraveling similar events but at late stage infection.

Methods

Model of alveolar echinococcosis

An established mouse model of primary alveolar echinococcosis was used as previously described [3], [69]. The animal studies were approved by the Animal Care and Experimentation Committee of the Canton of Bern, Switzerland, and followed National Institutes of Health guidelines for the performance of animal experiments. Briefly, 8-weeks-old female C57BL6/J mice were purchased from Charles River GmbH (Germany), and infected (n = 10) at the age of 10 weeks by peroral inoculation with 100 µl sterile water containing 2×103 eggs of E. multilocularis, using appropriate biosafety level 3 laboratory conditions (Swiss biosafety approval number A990006/3A). The infecting organisms (parasite eggs) were initially isolated from a naturally infected fox. Egg viability and infectiosity were pre-evaluated upon explorative titrated infection experiments carried out in mice preliminarily to the present studies [4]. Mock-infected control animals (n = 5) were perorally inoculated with 100 µl of sterile water. 31 days after infection, the animals were weighed and the infection intensity of AE was scored by counting the number of parasitic lesions macroscopically visible on and within the liver tissue [4]. Animals were sacrificed with an overdose of pentobarbital (100 mg/kg, intraperitoneally) for the mock-infected control group (n = 5) and for the group representing the chronic stage of primary AE (n = 10).

Tissue processing

Animals were perfused via the left cardiac ventricle with 30 ml of ice-cold, RNase-free phosphate buffered saline (PBS) followed by 30 ml of 50% RNAlater@ (Ambion Europe Ltd., Huntingdon, UK) in ice-cold, RNase-free PBS. Immediately afterwards, the liver was removed. Approximately 5 mm3–sized periparasitic liver tissue blocks (adjacent by 1 mm to the macroscopically visible parasitc lesion) were dissected and stored separately in 150 µl of RNAlater® at 4°C until isolation of RNA.

RNA processing and microarray hybridization

Liver tissue samples of each animal were processed and analyzed separately. Total RNA was extracted from liver tissue using RNeasy® Lipid Tissue kit (QIAGEN, Basel, Switzerland) and purified with RNeasy columns (QIAGEN, Basel, Switzerland). Quantification and assessment of RNA integrity were performed on the Agilent 2100 bioanalyzer platform (RNA 6000 Nano, Agilent technologies, Waldbronn, GER) and validated on the NanoDrop® (NanoDrop, Wilmington, USA) quantification device. Based on RNA quality control results and histopathological evaluation of hippocampal damage (apoptosis score) RNA extracts from 3 infected and 3 control animals were selected for each time point for array hybridization. Double-stranded cDNAs were synthesized from 5 µg of total RNA using an oligo dT-T7 promoter primer (Roche Molecular Biochemicals, Mannheim, Germany). The cDNAs obtained were used as templates for in vitro transcription using the Megascript kit purchased from Ambion (Austin, TX) and biotinylated nucleotides (Bio-11-CTP and Bio-16-UTP) provided by Roche Molecular Biochemicals (Basel, Switzerland). Fragmented in vitro transcripts (cRNAs) were hybridized overnight on to commercially available rat microarrays (GeneChip® Rat Genome 230 2.0 Array, Affymetrix, Santa Clara, CA) containing 31'000 probe sets representing approximately 28'000 well-substantiated rat genes. The hybridized samples were stained with streptavidin-R phycoerythrin (SAPE, Molecular Probes Inc., Eugene, OR) and the signal was amplified using a biotinylated goat anti-streptavidin antibody (Vector Laboratories, Burlingame, CA). Washing, staining and amplification were carried out in an Affymetrix GeneChip® Fluidics Station 450. Microarrays were scanned in an Affymetrix GeneChip® scanner 3000. Signal intensities were calculated based on image files with the Affymetrix GeneChip® Operating software (GCOS) v1.1.1.

Raw data analysis

Chip data analysis was performed on the R platform for statistical programming using packages of the Bioconductor project [70]. Due to the asymmetric distribution of microarray data all datasets were log2 transformed. Background correction, normalization and data summary were performed with non linear methods using the rma function of the affy package [71]. Chip quality assessment was exploratively performed based on boxplots of the raw log scale intensities and MA-plots visualizing signal intensity dependent effects on the log-ratios. Additionally the quality of the hybridized cRNA was assessed by RNA digestion plots where the mean intensities of all probes on an array are plotted according to their 5′ to 3′probeset position (affy package).

To reduce the number of hypothesis to be tested in the subsequent significant tests, genefiltering was perfomed. All genes that were expressed under the estimated background intensity of 60 fluorescent units (FU) on at least 4 of the 8 chips and genes showing an interquantile range (IRQ) of less than 0.5 were excluded from significance testing.

Significance testing was performed using the limma package [72]. Type 1 error was corrected by the Benjamini-Hochberg false discovery rate algorithm [73].

All raw data is MIAME compliant and have been deposited in “ArrayExpress” (EMBL/EBI) (accession no. E-MEXP-2615).

Custom-designed TaqMan® Gene Expression Assays

In order to obtain an ex vivo confirmation of the Affymetrix gene expression findings, we selected 18 (upregulated) out of the 36 genes initially differentially expressed, to subject them to a custom-designed real-time PCR Applied Biosystems 7900HT Micro Fluidic Card system. For this, TaqMan Low Density Arrays using 384-well micro fluidic cards were pre-loaded with a selection (Table 3) of differentially expressed genes (selection was primarily based upon the availability of standardized primer pairs to quantitatively investigate respective gene expression).

thumbnail
Table 3. Selected list of genes and respective primer sets to assess expression status at the mRNA level using a TaqMan® Custom Array microfluidic card system.

https://doi.org/10.1371/journal.pone.0009779.t003

Relative quantification was based on the reference of the following 5 constitutively expressed reference genes (Table 4). These genes were selected from the microarray data based on i) their minimal variability between the control and infection group ii) their absolute expression level covering the whole array signal range.

thumbnail
Table 4. The custom-designed TaqMan® Gene Expression Assays were quantified upon use of 5 constitutively expressed reference genes and corresponding primer sets, respectively.

https://doi.org/10.1371/journal.pone.0009779.t004

Acknowledgments

We thank Prof. Andrew Hemphill for fruitful and constructive discussions.

Author Contributions

Conceived and designed the experiments: BG MW MM SLL RJ. Performed the experiments: BG MW MS MM NM RJ. Analyzed the data: BG MW MS JM RJ. Contributed reagents/materials/analysis tools: BG. Wrote the paper: BG MW. Carried out microarray technology: MW. Carried out microfluidic gene expression assays: RJ.

References

  1. 1. Gottstein B, Piarroux R (2008) Current trends in tissue-affecting helminths. Parasite 15: 291–298.B. GottsteinR. Piarroux2008Current trends in tissue-affecting helminths.Parasite15291298
  2. 2. Gottstein B, Reichen J (2009) Echinococcosis/Hydatidosis. chapter 86. : 1549–1568.B. GottsteinJ. Reichen2009Echinococcosis/Hydatidosis.chapter 8615491568In: Manson's Tropical Diseases, 22nd edition, eds. GC Cook and AI Zumla, Saunders Elsevier Ltd.
  3. 3. Siles-Lucas M, Merli M, Mackenstedt U, Gottstein B (2003) The Echinococcus multilocularis 14-3-3 protein protects mice against primary but not secondary alveolar echinococcosis. Vaccine 21: 431–439. Parasite Immunol 20: 623–629.M. Siles-LucasM. MerliU. MackenstedtB. Gottstein2003The Echinococcus multilocularis 14-3-3 protein protects mice against primary but not secondary alveolar echinococcosis. Vaccine 21: 431–439.Parasite Immunol20623629
  4. 4. Gauci C, Merli M, Muller V, Chow C, Yagi K, et al. (2002) Molecular cloning of a vaccine antigen against infection with the larval stage of Echinococcus multilocularis. Infect Immun 70: 3969–3972.C. GauciM. MerliV. MullerC. ChowK. Yagi2002Molecular cloning of a vaccine antigen against infection with the larval stage of Echinococcus multilocularis.Infect Immun7039693972
  5. 5. Bauder B, Auer H, Schilcher F, Gabler C, Romig T, et al. (1999) Experimental investigations on the B and T cell immune response in primary alveolar echinococcosis. Parasite Immunol 21: 409–421.B. BauderH. AuerF. SchilcherC. GablerT. Romig1999Experimental investigations on the B and T cell immune response in primary alveolar echinococcosis.Parasite Immunol21409421
  6. 6. Zhao Y, Ferguson DJ, Wilson DC, Howard JC, Sibley LD, et al. (2009) Virulent Toxoplasma gondii evade immunity-related GTPase-mediated parasite vacuole disruption within primed macrophages. J Immunol 182: 3775–3781.Y. ZhaoDJ FergusonDC WilsonJC HowardLD Sibley2009Virulent Toxoplasma gondii evade immunity-related GTPase-mediated parasite vacuole disruption within primed macrophages.J Immunol18237753781
  7. 7. Weinländer K, Naschberger E, Lehmann MH, Tripal P, Paster W, et al. (2008) Guanylate binding protein-1 inhibits spreading and migration of endothelial cells through induction of integrin alpha4 expression. FASEB J 22: 4168–4178.K. WeinländerE. NaschbergerMH LehmannP. TripalW. Paster2008Guanylate binding protein-1 inhibits spreading and migration of endothelial cells through induction of integrin alpha4 expression.FASEB J2241684178
  8. 8. Degrandi D, Konermann C, Beuter-Gunia C, Kresse A, Würthner J, et al. (2007) Extensive characterization of IFN-induced GTPases mGBP1 to mGBP10 involved in host defense. J Immunol 179: 7729–7740.D. DegrandiC. KonermannC. Beuter-GuniaA. KresseJ. Würthner2007Extensive characterization of IFN-induced GTPases mGBP1 to mGBP10 involved in host defense.J Immunol17977297740
  9. 9. Schnoor M, Betanzos A, Weber DA, Parkos CA (2009) Guanylate-binding protein-1 is expressed at tight junctions of intestinal epithelial cells in response to interferon-gamma and regulates barrier function through effects on apoptosis. Mucosal Immunol 2: 33–42.M. SchnoorA. BetanzosDA WeberCA Parkos2009Guanylate-binding protein-1 is expressed at tight junctions of intestinal epithelial cells in response to interferon-gamma and regulates barrier function through effects on apoptosis.Mucosal Immunol23342
  10. 10. Brännström A, Sankala M, Tryggvason K, Pikkarainen T (2002) Arginine residues in domain V have a central role for bacteria-binding activity of macrophage scavenger receptor MARCO. Biochem Biophys Res Commun 290: 1462–1469.A. BrännströmM. SankalaK. TryggvasonT. Pikkarainen2002Arginine residues in domain V have a central role for bacteria-binding activity of macrophage scavenger receptor MARCO.Biochem Biophys Res Commun29014621469
  11. 11. Bandyopadhyay SK, de la Motte CA, Kessler SP, Hascall VC, Hill DR, et al. (2008) Hyaluronan-mediated leukocyte adhesion and dextran sulfate sodium-induced colitis are attenuated in the absence of signal transducer and activator of transcription 1. Am J Pathol 173: 1361–1368.SK BandyopadhyayCA de la MotteSP KesslerVC HascallDR Hill2008Hyaluronan-mediated leukocyte adhesion and dextran sulfate sodium-induced colitis are attenuated in the absence of signal transducer and activator of transcription 1.Am J Pathol17313611368
  12. 12. Neufert C, Becker C, Wirtz S, Fantini MC, Weigmann B, et al. (2007) IL-27 controls the development of inducible regulatory T cells and Th17 cells via differential effects on STAT1. Eur J Immunol 37: 1809–1816.C. NeufertC. BeckerS. WirtzMC FantiniB. Weigmann2007IL-27 controls the development of inducible regulatory T cells and Th17 cells via differential effects on STAT1.Eur J Immunol3718091816
  13. 13. Ramsauer K, Farlik M, Zupkovitz G, Seiser C, Kröger A, et al. (2007) Distinct modes of action applied by transcription factors STAT1 and IRF1 to initiate transcription of the IFN-gamma-inducible gbp2 gene. Proc Natl Acad Sci U S A 104: 2849–2854.K. RamsauerM. FarlikG. ZupkovitzC. SeiserA. Kröger2007Distinct modes of action applied by transcription factors STAT1 and IRF1 to initiate transcription of the IFN-gamma-inducible gbp2 gene.Proc Natl Acad Sci U S A10428492854
  14. 14. Jeong WI, Park O, Radaeva S, Gao B (2006) STAT1 inhibits liver fibrosis in mice by inhibiting stellate cell proliferation and stimulating NK cell cytotoxicity. Hepatology 44: 1441–1451.WI JeongO. ParkS. RadaevaB. Gao2006STAT1 inhibits liver fibrosis in mice by inhibiting stellate cell proliferation and stimulating NK cell cytotoxicity.Hepatology4414411451
  15. 15. Shuai K (2000) Modulation of STAT signaling by STAT-interacting proteins. Oncogene 19: 2638–2644.K. Shuai2000Modulation of STAT signaling by STAT-interacting proteins.Oncogene1926382644
  16. 16. Ramsey C, Rubinstein MP, Kim DM, Cho JH, Sprent J, et al. (2008) The lymphopenic environment of CD132 (common gamma-chain)-deficient hosts elicits rapid homeostatic proliferation of naive T cells via IL-15. J Immunol 180: 5320–5326.C. RamseyMP RubinsteinDM KimJH ChoJ. Sprent2008The lymphopenic environment of CD132 (common gamma-chain)-deficient hosts elicits rapid homeostatic proliferation of naive T cells via IL-15.J Immunol18053205326
  17. 17. Xiao H, Yin T, Wang XY, Uchida T, Chung J, et al. (2002) Specificity of interleukin-2 receptor gamma chain superfamily cytokines is mediated by insulin receptor substrate-dependent pathway. J Biol Chem 277: 8091–8098.H. XiaoT. YinXY WangT. UchidaJ. Chung2002Specificity of interleukin-2 receptor gamma chain superfamily cytokines is mediated by insulin receptor substrate-dependent pathway.J Biol Chem27780918098
  18. 18. Hawkins PT, Stephens LR (2007) PI3Kgamma is a key regulator of inflammatory responses and cardiovascular homeostasis. Science 318: 64–66.PT HawkinsLR Stephens2007PI3Kgamma is a key regulator of inflammatory responses and cardiovascular homeostasis.Science3186466
  19. 19. MacKinnon AC, Farnworth SL, Hodkinson PS, Henderson NC, Atkinson KM, et al. (2008) Regulation of alternative macrophage activation by galectin-3. J Immunol 180: 2650–2658.AC MacKinnonSL FarnworthPS HodkinsonNC HendersonKM Atkinson2008Regulation of alternative macrophage activation by galectin-3.J Immunol18026502658
  20. 20. Gantner BN, Simmons RM, Canavera SJ, Akira S, Underhill DM (2003) Collaborative induction of inflammatory responses by dectin-1 and Toll-like receptor 2. J Exp Med 197: 1107–1117.BN GantnerRM SimmonsSJ CanaveraS. AkiraDM Underhill2003Collaborative induction of inflammatory responses by dectin-1 and Toll-like receptor 2.J Exp Med19711071117
  21. 21. Liu N, Wang Y, Ashton-Rickardt PG (2004) Serine protease inhibitor 2A inhibits caspase-independent cell death. FEBS Lett 569: 49–53.N. LiuY. WangPG Ashton-Rickardt2004Serine protease inhibitor 2A inhibits caspase-independent cell death.FEBS Lett5694953
  22. 22. Faure-André G, Vargas P, Yuseff MI, Heuzé M, Diaz J, et al. (2008) Regulation of dendritic cell migration by CD74, the MHC class II-associated invariant chain. Science 322: 1705–1710.G. Faure-AndréP. VargasMI YuseffM. HeuzéJ. Diaz2008Regulation of dendritic cell migration by CD74, the MHC class II-associated invariant chain.Science32217051710
  23. 23. Manicone AM, Burkhart KM, Lu B, Clark JG (2008) CXCR3 ligands contribute to Th1-induced inflammation but not to homing of Th1 cells into the lung. Exp Lung Res 34: 391–407.AM ManiconeKM BurkhartB. LuJG Clark2008CXCR3 ligands contribute to Th1-induced inflammation but not to homing of Th1 cells into the lung.Exp Lung Res34391407
  24. 24. Zhai Y, Shen XD, Gao F, Zhao A, Freitas MC, et al. (2008) CXCL10 regulates liver innate immune response against ischemia and reperfusion injury. Hepatology 47: 207–214.Y. ZhaiXD ShenF. GaoA. ZhaoMC Freitas2008CXCL10 regulates liver innate immune response against ischemia and reperfusion injury.Hepatology47207214
  25. 25. Nakamichi K, Inoue S, Takasaki T, Morimoto K, Kurane I (2004) Rabies virus stimulates nitric oxide production and CXC chemokine ligand 10 expression in macrophages through activation of extracellular signal-regulated kinases 1 and 2. J Virol 78: 9376–9388.K. NakamichiS. InoueT. TakasakiK. MorimotoI. Kurane2004Rabies virus stimulates nitric oxide production and CXC chemokine ligand 10 expression in macrophages through activation of extracellular signal-regulated kinases 1 and 2.J Virol7893769388
  26. 26. Koniaris LG, Zimmers-Koniaris T, Hsiao EC, Chavin K, Sitzmann JV, et al. (2001) Cytokine-responsive gene-2/IFN-inducible protein-10 expression in multiple models of liver and bile duct injury suggests a role in tissue regeneration. J Immunol 167: 399–406.LG KoniarisT. Zimmers-KoniarisEC HsiaoK. ChavinJV Sitzmann2001Cytokine-responsive gene-2/IFN-inducible protein-10 expression in multiple models of liver and bile duct injury suggests a role in tissue regeneration.J Immunol167399406
  27. 27. Santiago HC, Oliveira CF, Santiago L, Ferraz FO, de Souza DG, et al. (2004) Involvement of the chemokine RANTES (CCL5) in resistance to experimental infection with Leishmania major. Infect Immun 72: 4918–4923.HC SantiagoCF OliveiraL. SantiagoFO FerrazDG de Souza2004Involvement of the chemokine RANTES (CCL5) in resistance to experimental infection with Leishmania major.Infect Immun7249184923
  28. 28. Xu H, Williams MS, Spain LM (2006) Patterns of expression, membrane localization, and effects of ectopic expression suggest a function for MS4a4B, a CD20 homolog in Th1 T cells. Blood 107: 2400–2408.H. XuMS WilliamsLM Spain2006Patterns of expression, membrane localization, and effects of ectopic expression suggest a function for MS4a4B, a CD20 homolog in Th1 T cells.Blood10724002408
  29. 29. Fujiwara K, Daido S, Yamamoto A, Kobayashi R, Yokoyama T, et al. (2008) Pivotal role of the cyclin-dependent kinase inhibitor p21WAF1/CIP1 in apoptosis and autophagy. J Biol Chem 283: 388–397.K. FujiwaraS. DaidoA. YamamotoR. KobayashiT. Yokoyama2008Pivotal role of the cyclin-dependent kinase inhibitor p21WAF1/CIP1 in apoptosis and autophagy.J Biol Chem283388397
  30. 30. Hui L, Zatloukal K, Scheuch H, Stepniak E, Wagner EF (2008) Proliferation of human HCC cells and chemically induced mouse liver cancers requires JNK1-dependent p21 downregulation. J Clin Invest 118: 3943–3953.L. HuiK. ZatloukalH. ScheuchE. StepniakEF Wagner2008Proliferation of human HCC cells and chemically induced mouse liver cancers requires JNK1-dependent p21 downregulation.J Clin Invest11839433953
  31. 31. Asefa B, Dermott JM, Kaldis P, Stefanisko K, Garfinkel DJ, et al. (2006) p205, a potential tumor suppressor, inhibits cell proliferation via multiple pathways of cell cycle regulation. FEBS Lett 580: 1205–1214.B. AsefaJM DermottP. KaldisK. StefaniskoDJ Garfinkel2006p205, a potential tumor suppressor, inhibits cell proliferation via multiple pathways of cell cycle regulation.FEBS Lett58012051214
  32. 32. Nagai Y, Shimazu R, Ogata H, Akashi S, Sudo K, et al. (2002) Requirement for MD-1 in cell surface expression of RP105/CD180 and B-cell responsiveness to lipopolysaccharide. Blood 99: 1699–1705.Y. NagaiR. ShimazuH. OgataS. AkashiK. Sudo2002Requirement for MD-1 in cell surface expression of RP105/CD180 and B-cell responsiveness to lipopolysaccharide.Blood9916991705
  33. 33. Shalev I, Wong KM, Foerster K, Zhu Y, Chan C, et al. (2009) The novel CD4+CD25+ regulatory T cell effector molecule fibrinogen-like protein 2 contributes to the outcome of murine fulminant viral hepatitis. Hepatology 49: 387–397.I. ShalevKM WongK. FoersterY. ZhuC. Chan2009The novel CD4+CD25+ regulatory T cell effector molecule fibrinogen-like protein 2 contributes to the outcome of murine fulminant viral hepatitis.Hepatology49387397
  34. 34. Liu H, Shalev I, Manuel J, He W, Leung E, et al. (2008) The FGL2-FcgammaRIIB pathway: a novel mechanism leading to immunosuppression. Eur J Immunol 38: 3114–3126.H. LiuI. ShalevJ. ManuelW. HeE. Leung2008The FGL2-FcgammaRIIB pathway: a novel mechanism leading to immunosuppression.Eur J Immunol3831143126
  35. 35. Stanley AC, Dalton JE, Rossotti SH, MacDonald KP, Zhou Y, et al. (2008) VCAM-1 and VLA-4 modulate dendritic cell IL-12p40 production in experimental visceral leishmaniasis. PLoS Pathog 19 4(9): e1000158.AC StanleyJE DaltonSH RossottiKP MacDonaldY. Zhou2008VCAM-1 and VLA-4 modulate dendritic cell IL-12p40 production in experimental visceral leishmaniasis.PLoS Pathog 194(9)e1000158
  36. 36. Bansal G, Druey KM, Xie Z (2007) R4 RGS proteins: regulation of G-protein signaling and beyond. Pharmacol Ther 116: 473–495.G. BansalKM DrueyZ. Xie2007R4 RGS proteins: regulation of G-protein signaling and beyond.Pharmacol Ther116473495
  37. 37. Yang D, Chen Q, Su SB, Zhang P, Kurosaka K, et al. (2008) Eosinophil-derived neurotoxin acts as an alarmin to activate the TLR2-MyD88 signal pathway in dendritic cells and enhances Th2 immune responses. J Exp Med 205: 79–90.D. YangQ. ChenSB SuP. ZhangK. Kurosaka2008Eosinophil-derived neurotoxin acts as an alarmin to activate the TLR2-MyD88 signal pathway in dendritic cells and enhances Th2 immune responses.J Exp Med2057990
  38. 38. Nakajima M, Hirakata M, Nittoh T, Ishihara K, Ohuchi K (2001) Expression and purification of recombinant rat eosinophil-associated ribonucleases, homologues of human eosinophil cationic protein and eosinophil-derived neurotoxin, and their characterization. Int Arch Allergy Immunol 125: 241–249.M. NakajimaM. HirakataT. NittohK. IshiharaK. Ohuchi2001Expression and purification of recombinant rat eosinophil-associated ribonucleases, homologues of human eosinophil cationic protein and eosinophil-derived neurotoxin, and their characterization.Int Arch Allergy Immunol125241249
  39. 39. Yang D, Rosenberg HF, Chen Q, Dyer KD, Kurosaka K, et al. (2003) Eosinophil-derived neurotoxin (EDN), an antimicrobial protein with chemotactic activities for dendritic cells. Blood 102: 3396–3403.D. YangHF RosenbergQ. ChenKD DyerK. Kurosaka2003Eosinophil-derived neurotoxin (EDN), an antimicrobial protein with chemotactic activities for dendritic cells.Blood10233963403
  40. 40. Mead JR, Irvine SA, Ramji DP (2002) Lipoprotein lipase: structure, function, regulation, and role in disease. J Mol Med 80: 753–769.JR MeadSA IrvineDP Ramji2002Lipoprotein lipase: structure, function, regulation, and role in disease.J Mol Med80753769
  41. 41. Wilson JE (2003) Isozymes of mammalian hexokinase: structure, subcellular localization and metabolic function. J Exp Biol 206: 2049–2057.JE Wilson2003Isozymes of mammalian hexokinase: structure, subcellular localization and metabolic function.J Exp Biol20620492057
  42. 42. Fujii C, Nakamoto Y, Lu P, Tsuneyama K, Popivanova BK, et al. (2005) Aberrant expression of serine/threonine kinase Pim-3 in hepatocellular carcinoma development and its role in the proliferation of human hepatoma cell lines. Int J Cancer 114: 209–218.C. FujiiY. NakamotoP. LuK. TsuneyamaBK Popivanova2005Aberrant expression of serine/threonine kinase Pim-3 in hepatocellular carcinoma development and its role in the proliferation of human hepatoma cell lines.Int J Cancer114209218
  43. 43. Macdonald A, Campbell DG, Toth R, McLauchlan H, Hastie CJ, et al. (2006) Pim kinases phosphorylate multiple sites on Bad and promote 14-3-3 binding and dissociation from Bcl-XL. BMC Cell Biol 10 7: 1.A. MacdonaldDG CampbellR. TothH. McLauchlanCJ Hastie2006Pim kinases phosphorylate multiple sites on Bad and promote 14-3-3 binding and dissociation from Bcl-XL.BMC Cell Biol 1071
  44. 44. Agnihotri G, Liu HW (2003) Enoyl-CoA hydratase. reaction, mechanism, and inhibition. Bioorg Med Chem 11: 9–20.G. AgnihotriHW Liu2003Enoyl-CoA hydratase. reaction, mechanism, and inhibition.Bioorg Med Chem11920
  45. 45. Bresson-Hadni S, Liance M, Meyer JP, Houin R, Bresson JL, et al. (1990) Cellular immunity in experimental Echinococcus multilocularis infection. II. Sequential and comparative phenotypic study of the periparasitic mononuclear cells in resistant and sensitive mice. Clin Exp Immunol 82: 378–383.S. Bresson-HadniM. LianceJP MeyerR. HouinJL Bresson1990Cellular immunity in experimental Echinococcus multilocularis infection. II. Sequential and comparative phenotypic study of the periparasitic mononuclear cells in resistant and sensitive mice.Clin Exp Immunol82378383
  46. 46. Emery I, Liance M, Deriaud E, Vuitton DA, Houin R, et al. (1996) Characterization of T-cell immune responses of Echinococcus multilocularis-infected C57BL/6J mice. Parasite Immunol 18: 463–472.I. EmeryM. LianceE. DeriaudDA VuittonR. Houin1996Characterization of T-cell immune responses of Echinococcus multilocularis-infected C57BL/6J mice.Parasite Immunol18463472
  47. 47. Playford MC, Kamiya M (1992) Immune respoflse to Echinococcus multilocularis infection in the mouse model. Jpn J Vet Res 40: 113–130.MC PlayfordM. Kamiya1992Immune respoflse to Echinococcus multilocularis infection in the mouse model.Jpn J Vet Res40113130
  48. 48. Playford MC, Ooi HK, Oku Y, Kamiya M (1992) Secondary Echinococcus multilocularis infection in severe combined immunodeficient (scid) mice: biphasic growth of the larval cyst mass. Int J Parasitol 22: 975–982.MC PlayfordHK OoiY. OkuM. Kamiya1992Secondary Echinococcus multilocularis infection in severe combined immunodeficient (scid) mice: biphasic growth of the larval cyst mass.Int J Parasitol22975982
  49. 49. Sailer M, Soelder B, Allerberger F, Zaknun D, Feichtinger H, et al. (1997) Alveolar echinococcosis of the liver in a six-year-old girl with acquired immunodeficiency syndrome. J Pediatr 130: 320–323.M. SailerB. SoelderF. AllerbergerD. ZaknunH. Feichtinger1997Alveolar echinococcosis of the liver in a six-year-old girl with acquired immunodeficiency syndrome.J Pediatr130320323
  50. 50. Zingg W, Renner-Schneiter EC, Pauli-Magnus C, Renner EL, van Overbeck J, et al. (2002) Alveolar echinococcosis of the liver in an adult with human immunodeficiency virus type-1 infection. Infection 32: 299–302.W. ZinggEC Renner-SchneiterC. Pauli-MagnusEL RennerJ. van Overbeck2002Alveolar echinococcosis of the liver in an adult with human immunodeficiency virus type-1 infection.Infection32299302
  51. 51. Liance M, Aicard-Blum S, Emery I, Houin A, Vuitton DA (1998) Echinococcus multilocularis infection in mice: in vivo treatment with a low dose of IFN-gamma decreases metacestode growth and liver fibrogenesis. Parasite 5: 231–237.M. LianceS. Aicard-BlumI. EmeryA. HouinDA Vuitton1998Echinococcus multilocularis infection in mice: in vivo treatment with a low dose of IFN-gamma decreases metacestode growth and liver fibrogenesis.Parasite5231237
  52. 52. Jenne L, Kilwinski J, Aadloff P, Flick W, Kern P (1998) Clinical efficacy of and immunologic alterations caused by interferon gamma therapy for alveolar echinococcosis. Clin Infect Dis 26: 492–494.L. JenneJ. KilwinskiP. AadloffW. FlickP. Kern1998Clinical efficacy of and immunologic alterations caused by interferon gamma therapy for alveolar echinococcosis.Clin Infect Dis26492494
  53. 53. Amiot F, Vuong P, Defontaines M, Pater C, Dautry F, et al. (1999) Secondary alveolar echinococcosis in Iymphotoxinalpha and tumour necrosis factor-alpha deficient mice: exacerbation of Echinococcus multilocularis larval growth is associated with cellular changes in the periparasitic granuloma. Parasite Immunol 21: 475–483.F. AmiotP. VuongM. DefontainesC. PaterF. Dautry1999Secondary alveolar echinococcosis in Iymphotoxinalpha and tumour necrosis factor-alpha deficient mice: exacerbation of Echinococcus multilocularis larval growth is associated with cellular changes in the periparasitic granuloma.Parasite Immunol21475483
  54. 54. Godot V, Harraga S, Podoprigora G, Liance M, Bardonnet K, et al. (2003) IFN alpha-2a protects mice against a helminth infection of the liver and modulates immune responses. Gastroenterol 124: 1441–1450.V. GodotS. HarragaG. PodoprigoraM. LianceK. Bardonnet2003IFN alpha-2a protects mice against a helminth infection of the liver and modulates immune responses.Gastroenterol12414411450
  55. 55. Emery I, Leclerc C, Sengphommachanh K, Vuitton DA, Liance M (1998) In vivo treatment with recombinant IL-12 protects C57BL/6J mice against secondary alveolar echinococcosis. Parasite Immunol 20: 81–91.I. EmeryC. LeclercK. SengphommachanhDA VuittonM. Liance1998In vivo treatment with recombinant IL-12 protects C57BL/6J mice against secondary alveolar echinococcosis.Parasite Immunol208191
  56. 56. Vuitton DA (2003) The ambiguous role of immunity in echinococcosis: protection of the host or of the parasite? Acta Trop 85: 119–132.DA Vuitton2003The ambiguous role of immunity in echinococcosis: protection of the host or of the parasite?Acta Trop85119132
  57. 57. Dai WJ, Waldvogel A, Jungi T, Stettler M, Gottstein B (2003) Inducible nitric oxide synthase-deficiency in mice increases resistance to chronic infection with Echinococcus multilocularis. Immunol 10: 238–244.WJ DaiA. WaldvogelT. JungiM. StettlerB. Gottstein2003Inducible nitric oxide synthase-deficiency in mice increases resistance to chronic infection with Echinococcus multilocularis.Immunol10238244
  58. 58. Mejri N, Gottstein B (2006) Intraperitoneal Echinococcus multilocularis infection in C57BL/6 mice inhibits the up-regulation of B7-1 and B7-2 co-stimulator expression on peritoneal macrophages and causes failure to enhance peritoneal T cell activation. Parasite Immunol 28: 373–385.N. MejriB. Gottstein2006Intraperitoneal Echinococcus multilocularis infection in C57BL/6 mice inhibits the up-regulation of B7-1 and B7-2 co-stimulator expression on peritoneal macrophages and causes failure to enhance peritoneal T cell activation.Parasite Immunol28373385
  59. 59. Mejri N, Gottstein B (2009) Echinococcus multilocularis metacestode metabolites contain a cysteine protease that digests eotaxin, a CC pro-inflammatory chemokine. Parasitol Res, Jul 2 [Epub ahead of print]. N. MejriB. Gottstein2009Echinococcus multilocularis metacestode metabolites contain a cysteine protease that digests eotaxin, a CC pro-inflammatory chemokine.Parasitol Res, Jul 2 [Epub ahead of print]
  60. 60. Pennock JL, Grencis RK (2006) The mast cell and gut nematodes: damage and defence. Chem Immunol Allergy 90: 128–140.JL PennockRK Grencis2006The mast cell and gut nematodes: damage and defence.Chem Immunol Allergy90128140
  61. 61. Baron RW, Tanner CE (1976) The effect of immunosuppression on secondary Echinococcus multilocularis infections in mice. Int J Parasitol 6: 37–42.RW BaronCE Tanner1976The effect of immunosuppression on secondary Echinococcus multilocularis infections in mice.Int J Parasitol63742
  62. 62. Devouge M, Ali-Khan Z (1983) Intraperitoneal murine alveolar hydatidosis: relationship between the size of the larval cyst mass, immigrant inflammatory cells, splenomegaly and thymus involution. Tropenmed Parasito! 34: 15–20.M. DevougeZ. Ali-Khan1983Intraperitoneal murine alveolar hydatidosis: relationship between the size of the larval cyst mass, immigrant inflammatory cells, splenomegaly and thymus involution.Tropenmed Parasito!341520
  63. 63. Kizaki T, Ishige M, Bingyan W, Day NK, Good RA, et al. (1993) Generation of CD8+ suppressor T cells by proto scoleces of Echinococcus multilocularis in vitro. Immunol 79: 412–417.T. KizakiM. IshigeW. BingyanNK DayRA Good1993Generation of CD8+ suppressor T cells by proto scoleces of Echinococcus multilocularis in vitro.Immunol79412417
  64. 64. Stanley AC, Dalton JE, Rossotti SH, MacDonald KP, Zhou Y, et al. (2008) VCAM-1 and VLA-4 modulate dendritic cell IL-12p40 production in experimental visceral leishmaniasis. PLoS Pathog 19: e1000158.AC StanleyJE DaltonSH RossottiKP MacDonaldY. Zhou2008VCAM-1 and VLA-4 modulate dendritic cell IL-12p40 production in experimental visceral leishmaniasis.PLoS Pathog19e1000158
  65. 65. Vuitton DA, Zhang SL, Yang Y, Godot V, Beurton I, et al. (2006) Survival strategy of Echinococcus multilocularis in the human host. Parasitol 55: S51–S55.DA VuittonSL ZhangY. YangV. GodotI. Beurton2006Survival strategy of Echinococcus multilocularis in the human host.Parasitol55S51S55
  66. 66. Bernthaler P, Epping K, Schmitz G, Deplazes P, Brehm K (2009) Molecular characterization of EmABP, an apolipoprotein A-I binding protein secreted by the Echinococcus multilocularis metacestode. Infect Immun 77: 5564–5571.P. BernthalerK. EppingG. SchmitzP. DeplazesK. Brehm2009Molecular characterization of EmABP, an apolipoprotein A-I binding protein secreted by the Echinococcus multilocularis metacestode.Infect Immun7755645571
  67. 67. McManus DP (2009) Reflections on the biochemistry of Echinococcus: past, present and future. Parasitology 136: 1643–1652.DP McManus2009Reflections on the biochemistry of Echinococcus: past, present and future.Parasitology13616431652
  68. 68. Vuitton DA, Guerret-Stocker S, Carbillet JP, Mantion G, Miguet JP, et al. (1986) Collagen immunotyping of the hepatic fibrosis in human alveolar echinococcosis. Z Parasitenkd 72: 97–104.DA VuittonS. Guerret-StockerJP CarbilletG. MantionJP Miguet1986Collagen immunotyping of the hepatic fibrosis in human alveolar echinococcosis.Z Parasitenkd7297104
  69. 69. Pater C, Müller V, Harraga S, Liance M, Godot V, et al. (1998) Intestinal and systemic humoral immunological events in the susceptible Balb/C mouse strain after oral administration of Echinococcus multilocularis eggs.C. PaterV. MüllerS. HarragaM. LianceV. Godot1998Intestinal and systemic humoral immunological events in the susceptible Balb/C mouse strain after oral administration of Echinococcus multilocularis eggs.
  70. 70. Gentleman RC, Carey VJ, Bates DM, Bolstad B, Dettling M, et al. (2004) Bioconductor: open software development for computational biology and bioinformatics. Genome Biol 5: R80.RC GentlemanVJ CareyDM BatesB. BolstadM. Dettling2004Bioconductor: open software development for computational biology and bioinformatics.Genome Biol5R80
  71. 71. Gautier L, Cope L, Bolstad BM, Irizarry RA (2004) Affy-analysis of Affymetrix GeneChip data at the probe level. Bioinformatics 20: 307–315.L. GautierL. CopeBM BolstadRA Irizarry2004Affy-analysis of Affymetrix GeneChip data at the probe level.Bioinformatics20307315
  72. 72. Kooperberg C, Aragaki A, Strand AD, Olson JM (2005) Significance testing for small microarray experiments. Stat Med 24: 2281–2298.C. KooperbergA. AragakiAD StrandJM Olson2005Significance testing for small microarray experiments.Stat Med2422812298
  73. 73. Benjamini Y, Drai D, Elmer G, Kafkafi N, Golani I (2001) Controlling the false discovery rate in behavior genetics research. Behav Brain Res 125: 279–284.Y. BenjaminiD. DraiG. ElmerN. KafkafiI. Golani2001Controlling the false discovery rate in behavior genetics research.Behav Brain Res125279284