Published online before print January 3, 2008, doi: 10.1161/ATVBAHA.107.157438
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© 2008 American Heart Association, Inc.
Cell Biology/Signaling |
Wnt5A/CaMKII Signaling Contributes to the Inflammatory Response of Macrophages and Is a Target for the Antiinflammatory Action of Activated Protein C and Interleukin-10
From the Molecular and Clinical Inflammation Research Unit (C.P., D.J.S., G.S.), Medical Clinic, Department of Medicine, University Hospital of Zürich, Switzerland; Medical Clinic (E.B.B.), Uster Hospital, Uster, Switzerland; and Clinical Pathology, Department of Pathology (M.O.K.), University Hospital of Zurich, Zurich, Switzerland.
Correspondence to Gabriele Schoedon, PhD, Department of Medicine, University Hospital of Zurich, Rämistrasse 100, CH-8091 Zurich, Switzerland. E-mail klinsog{at}usz.unizh.ch
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Abstract |
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Objective— Sepsis is a major cause of death for intensive care patients. High concentrations of inflammatory cytokines are characteristic of severe systemic inflammation and activated monocytes are their predominant cellular source. To identify targets for antiinflammatory intervention, we investigated the response of human macrophages to inflammatory and antiinflammatory mediators.
Methods and Results— We profiled gene expression in human macrophages exposed to lipopolysaccharide (LPS) and interferon (IFN)-
in the presence or absence of recombinant activated protein C (APC) or IL-10 and identified Wnt5A as one of the transcripts most highly induced by LPS/IFN- and suppressed by APC and IL-10. We confirmed regulation of Wnt5A protein in macrophages and detected it in sera and bone marrow macrophages of patients with severe sepsis. We established that a functional Wnt5A/frizzled-5/CaMKII signaling pathway was essential for macrophage inflammatory activation. To prove the essential contribution of Wnt5A we measured inflammatory cytokines after stimulation with Wnt5A, silenced Wnt5A by siRNA, and blocked receptor binding with soluble Frizzled–related peptide-1 (sFRP1).
Conclusion— Wnt5A is critically involved in inflammatory macrophage signaling in sepsis and is a target for antiinflammatory mediators like APC or antagonists like sFRP1.
Gene expression profiling in human macrophages exposed to LPS and INF- in the presence or absence of recombinant APC or IL-10 identified Wnt5A as one of the most prominently regulated transcripts by these mediators. Wnt5A is critically involved in inflammatory macrophage signaling in sepsis.
Key Words: geneexpression • macrophages • activated protein C
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Introduction |
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Sepsis is a suspected or proven infection with a systemic inflammatory response. In severe sepsis, organ dysfunction also occurs and it is associated with a high mortality and morbidity. Severe sepsis still causes about 9.3% of all deaths in the USA.1,2
See accompanying article on page 400
During sepsis, the extent of plasma protein C depletion correlates with the severity of the outcome.3 In animal studies4 and clinical trials APC prevented death from severe sepsis or septic shock.5 Although this beneficial effect of APC is mostly ascribed to its anticoagulant properties, antiinflammatory effects of APC have also been proposed.6 The direct modulation of inflammation by APC has recently been described in gene expression profiling studies with human endothelial cells.7,8 Recently, recombinant human APC has been introduced as a therapeutic agent for treatment of patients with severe sepsis because of its unique anticoagulant and antiinflammatory properties; however, the exact mechanism of antiinflammatory action is still unknown.9
Macrophages play a central role in inflammation by responding to and releasing of numerous inflammatory cytokines and chemokines, leading to severe systemic inflammation and septic shock. However, the knowledge of antiinflammatory interactions on the level of monocytes/macrophages is scant. Therefore, we decided to expand our investigations on antiinflammatory effects of APC on this cellular system. In the present study, we were using a whole genome expression analysis approach, to define novel targets of APC in an in vitro model of inflammatory macrophage activation. Using probes obtained from human macrophages stimulated by INF- (IFN-) and endotoxin (LPS), we consistently found Wnt5A to be one of the genes induced by inflammatory stimuli and LPS which was blocked by APC at the transcriptional level.
Wnt5A is a member of the Wnt family of secreted signaling molecules, homologs of the Wingless proteins in Drosophila species.10 Wnt proteins are involved in embryonic development, in differentiation of white blood cells during mammalian hematopoiesis, and in tumorigenesis.11 The canonical Wnt signaling pathway controls target gene transcription via the central component β-catenin.12 Recently, regulation of β-catenin dependent gene transcription has been elucidated,13 and in mammalian cell systems it predominantly involves Wnt3.11 However, in our proinflammatory activated human macrophage cellular system, Wnt3 expression was extremely low (see supplemental Table II, available online at http://atvb.ahajournals.org), and the canonical signaling pathway was not affected by either proinflammatory activation or by APC and IL-10. Recently, a member of the Drosophila Wnt protein family, WntD, has been linked to Toll/NF-
B signaling and shown to be involved in antibacterial defense against Listeria monocytogenes in a septic fly model.14 Furthermore, in a recent study Wnt5A and its receptor Frizzled-5 (FZD5) are involved in regulation of the response to microbial stimulation in human mononuclear phagocytes.15
Here we show that Wnt5A acts through Ca2+/calmodulin-dependent protein kinase (CaMKII) and that this pathway contributes to the inflammatory response of human macrophages. APC and IL-10 modulate Wnt5A/CaMKII signaling in an antiinflammatory manner. The presence of high levels of Wnt5A in sera of patients with severe sepsis or septic shock and in activated macrophages from the bone marrow of septic shock patients suggests a critical role for Wnt5A in systemic inflammation and sepsis. Taken together, our study shows for the first time that, first, Wnt5A signaling is essential to the general inflammatory response of human macrophages and, second, APC acts antiinflammatory in activated human macrophages by interfering with Wnt5A signaling.
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Methods |
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Cell Culture
Human PBMC derived macrophages were cultured as described in the supplement (available online at http://atvb.ahajournals.org).
Gene Array Experiments
Gene expression profiling was performed by competitive dual-color hybridization of complementary RNA probes on human 44K 60-meroligonucleotide microarray chips (Agilent Technologies) as described in the supplement.
Quantitative Real Time RT-PCR
Real-Time PCR is described in the supplement.
Antibodies
The following antibodies were used for Western blotting and immunofluorescence: goat-anti-Wnt5A (1:1000, R&D Systems), rabbit-anti-FZD5 (1:1000, Abcam), rabbit-anti-CaMKII (1:1000, Abcam), rabbit-anti-active CaMKII (pT286; 1:500, Promega).
Western Blotting
Detection of FZD5 and CaMKII protein expression was performed by Western blotting and is described in the supplement.
Immunohistochemistry and Immunofluorescence
Details about immunohistochemistry and immunofluorescence experiments are given in the supplement. Fluorescent signal intensity was quantified using SigmaScan-Pro software (Systat-Software Inc).
Quantitation of Secreted Cytokines
Measurement of secreted IL-6, IL-8, IL-1β, and MIP-1β is described in the supplement.
Immunoprecipitation of Wnt5A in Sera
Detection of Wnt5A in the sera of septic patients and healthy individuals was performed by immunoprecipitation as described in the supplement.
Generation of Small Interfering RNA (siRNA) and Transfection of Macrophages
Wnt5A siRNA silencing experiments were performed as described in the supplement.
Statistical Analysis
Data were analyzed with the use of Graphpad-Prism version 4.0 statistical software. We used an unpaired 2-tailed Student t test or, for comparison of data among groups, 1-way ANOVA followed by the Newman–Keuls test. probability values <0.05 were considered statistically significant.
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Results |
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Identification of Targets for the Antiinflammatory Action of IL-10 and APC by Gene Expression Profiling
To define novel targets for antiinflammatory intervention, preferably at an early stage of the inflammatory response, we applied microarray based comparative transcriptome analysis in our model of monocyte derived macrophages.
The mRNA expression profiles of macrophages incubated with LPS/INF with or without IL-10 or APC for 8 hours were compared with the expression profiles of untreated macrophages (common reference, cultured in parallel) by competitive 2-color hybridization on human whole genome oligonucleotide array chips. The cytokine IL-10, which has well described antiinflammatory properties, was used to compare its effect with the suspected but not elucidated antiinflammatory action of APC in our setting of inflammatory activated macrophages. Analysis of experiments with macrophages from 3 different donors revealed a set of genes induced by LPS/INF (see supplemental Table I). Complete data are available in the ArrayExpress database with the following accession number, E-MEXP-927. In addition to several known inflammatory genes such as IL1β (87-fold induction compared with untreated cells), IL6 (15-fold), IL8 (3-fold), CCL2 (17-fold), and CCL4 (14-fold), Wnt5A was strongly induced by LPS/INF (79-fold, see supplemental Table I). Antiinflammatory stimuli reduced Wnt5A induction 2.7-fold by APC and 4.2-fold by IL-10 (supplemental Figure I). Furthermore, the FZD5 and CaMKII genes, which encode proteins involved in Wnt signaling pathways, were also differentially expressed. Both the genes for the receptor FDZ5 and for the signaling enzyme CaMKII are not upregulated by LPS/INF in presence of APC or IL10.
IL-10 and APC Regulate the Wnt5A/Ca2+ Pathway at the mRNA Expression and Protein Level
Quantitative RT-PCR verified that the expression and regulation of Wnt5A mRNA was induced by LPS/INF in human macrophages and that the level of induction of Wnt5A mRNA was reduced by the action of IL-10 and APC (Figure 1a). Transcriptional expression of Wnt5A was maximal at 8 hours in activated macrophage and declined rapidly within 24 to 48 hours to normal levels compared with unstimulated cells (data not shown). To test whether Wnt5A is also induced by signals targeting Toll-like receptors (TLR), we investigated a representative array of TLR agonists targeting TLR 1-9, and found that only PamCSK4 (TLR 1/2 agonist) and Imiquimod (TLR 7 agonist) did not induce Wnt5A mRNA transcription. All other TLR agonists induced Wnt5A expression more than 10-fold (Figure 1b). Immunocytochemistry was used to assess the levels of accumulated Wnt5A protein in activated macrophages (Figure 1c). After 24-hour incubation with LPS/INF, Wnt5A protein expression had increased in macrophages compared with untreated control cells. In contrast, after treatment with LPS/INF/IL-10 or LPS/INF/APC Wnt5A protein expression was unchanged in macrophages compared with untreated control cells (see Figure 1d). This observation leads us to the assumption that Wnt5A expression is induced by LPS/INF and that this effect is suppressed by IL-10 and APC.
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FZD5 and CaMKII Are Present and Contribute to Wnt5A Signaling in Macrophages that Can Be Blocked by a sFRP1
Western blot analysis showed FZD5 and CaMKII expression in macrophages, providing further evidence that these important components of the Wnt5A signaling pathway are present (Figure 2a). FZD5 protein was present as a single band with a molecular weight of 250 kDa. There were no detectable differences in the amount of protein in response to different treatments. CaMKII was present as a single band with a molecular weight of 60 kDa. Although it was not possible to establish whether the amount of CaMKII protein increased in macrophages stimulated with LPS/INF, CaMKII protein expression clearly decreased because of the action of APC. To address CaMKII activation by Wnt5A, we used a specific polyclonal antibody that recognizes only the phosphorylated form of CaMKII. Activation of CaMKII by Wnt5A and by LPS/INF was confirmed by immunofluorescence in cultured macrophages (Figure 2b and 2c). To corroborate our evidence for the contribution of Wnt5A to the inflammatory response of human macrophages, we blocked Wnt5A signaling at the ligand/receptor stage. sFRP1 is a member of the sFRP family that contains a cysteine-rich domain homologous to the putative Wnt binding site of Frizzled proteins, and it can act as a soluble modulator of Wnt signaling by specifically binding to Wnt5A21. Incubating macrophages with sFRP1 in addition to LPS/INF or recombinant Wnt5A reduced CaMKII phosphorylation, indicating that the Wnt5A signaling pathway was activated by inflammatory stimuli and that sFRP1 blocked this activation by preventing binding of Wnt5A to its receptor, FZD5 (Figure 2b and 2c).
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Wnt5A Stimulates the Release of Proinflammatory Cytokines in Macrophages, and IL-10 or APC Block the Inflammatory Action of Wnt5A
The biologic response of macrophages to an inflammatory stimulus is the synthesis and secretion of an array of inflammatory cytokines and chemokines. In a next series of experiments we wanted to know whether Wnt5A itself could account for a comparable effect on inflammatory cytokine production as LPS/IFN-. To investigate the biologic response to Wnt5A we quantified the levels of the proinflammatory cytokines IL-6, IL-8, IL-1β, and MIP-1β in supernatants of macrophage cultures treated for 24 hours with recombinant mouse Wnt5A. As shown in Figure 3, recombinant Wnt5A, expressed in a mammalian cell system and without detectable endotoxin concentrations (see method section), did indeed stimulate the release of proinflammatory cytokines in macrophages (black bars) in a comparable manner to cells that were stimulated with LPS/INF- (data not shown). Furthermore, IL-10 (gray bars) or APC (open bars) prevented the inflammatory cytokine release on stimulation with Wnt5A (Figure 3). There were again common and distinct effects of IL-10 and APC. The antiinflammatory effects of IL-10 and APC were comparably strong reducing IL-1 and MIP-1 production, whereas the effect of APC on IL-6 or IL-8 production was not as impressive as IL-10.
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Blocking Wnt5A Signaling Influences the Expression of Inflammatory Cytokines
To examine the Wnt5A contribution to the inflammatory response in macrophages further, we generated small interfering RNA (siRNA) against Wnt5A by transcription and dicing of a human Wnt5A specific template and investigated whether inhibition by siRNA of Wnt5A transcription influences the transcription and secretion of inflammatory cytokines. Transfection of unstimulated macrophages with anti-Wnt5A siRNA decreased Wnt5A activity by 80%, but did not significantly affect macrophage viability (data not shown). However, in LPS/INF- stimulated macrophages, knockdown of Wnt5A significantly decreased transcription of Wnt5A (Figure 4a). To ensure specificity of the observed effect of siRNA directed against Wnt5A, we measured expression of the housekeeping gene HPRT and found no significant change (Figure 4a). Moreover, knockdown of Wnt5A significantly decreased transcription and secretion of the inflammatory cytokines IL-1β, IL-6, and IL-8 (Figure 4b). Transfection with siRNA directed against luciferase GL3 duplex had no effect on the response to LPS/INF compared with mock-transfected cells (data not shown). These results further support a mechanism by which Wnt5A influences the transcription and release of inflammatory cytokines. Because of our previous observation that sFRP1 blocked CaMKII phosphorylation induced by LPS/INF stimulation we incubated stimulated human macrophages with sFRP1. We verified that sFRP1 inhibited the release of IL-1β, IL-6, IL-8, and MIP-1β in macrophages cultured under inflammatory conditions, which confirms that Wnt5A signaling caused secretion of proinflammatory cytokines (Figure 4c).
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Wnt5A Protein Is Present in the Serum and Bone Marrow of Patients With Severe Sepsis or Septic Shock
Because of the high levels of Wnt5A induced by inflammatory stimuli in vitro, we determined whether Wnt5A is present in vivo. Because Wnt5A is secreted, we suggested its presence in sera of septic patients. Thus we performed immunoprecipitation in archive sera samples from patients with severe sepsis or septic shock defined according to the criteria set forth by the 2003 International Sepsis Definitions Conference16 using a Wnt5A specific polyclonal antibody. Supernatants of transfected cells expressing and secreting large amounts of Wnt5A16 served as controls (Figure 5a). Densitometric analysis showed a distinct difference between the amounts of Wnt5A protein in patient samples compared with sera from healthy individuals (Figure 5b). Wnt5A concentration in sera of patients could be affected by kidney failure or disturbances of liver function, which occur often in patients with severe sepsis or septic shock. Serum creatinine concentrations were normal in all sera tested. In addition, neopterin, a marker of activated human macrophages, was significantly elevated only in the sera of sepsis patients (Figure 5b). The finding of elevated Wnt5A in sera of patients suggests an active role for secreted Wnt5A in the pathophysiology of sepsis. To confirm this observation, we demonstrated Wnt5A expression in macrophages of bone marrow samples of patients with fatal sepsis.17 Immunohistochemical analysis showed that there was intense staining for Wnt5A in hemophagocytic macrophages in these patients compared with bone marrow from healthy individuals. Again, sections of Wnt5A expressing cells and L-cells served as positive and negative controls, respectively, as they were fixed and stained in the same manner. The intensity of Wnt5A staining in the untransfected L-cells (background staining) was comparable to that found in bone marrow sections of healthy individuals (Figure 5c).
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Discussion |
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In this study we found that expression of Wnt5A is pivotal in a pathway involved in sustained inflammatory macrophage activation during sepsis. Our initial studies aimed to identify novel targets of the antiinflammatory activity of APC in pharmacological doses used in sepsis patients, in macrophages.
Beyond modulation of coagulation activation, the pleiotropic antiinflammatory activities of APC that are directed to different cellular targets are proposed to contribute to the uniquely beneficial activity of this agent in patients with severe sepsis. In a genome wide transcriptional screen of macrophages stimulated with LPS and IFN-, we have identified Wnt5A as one of the most highly induced genes. Suppression of inflammation-forced Wnt5A expression by APC and IL-10 implicated Wnt5A in an active role in the inflammatory response. Both the inflammatory driven transcriptional expression of Wnt5A and its suppression by APC and IL-10 were confirmed by independent methods at the mRNA and protein levels. Furthermore, high levels of immunoprecipitatable Wnt5A in sera from patients with severe sepsis provided direct evidence of an active role for secreted Wnt5A in the pathophysiology of the systemic inflammatory response during sepsis. Although our studies did not intend to identify the cellular source of Wnt5A secretion during sepsis, demonstration of Wnt5A positive macrophages within the bone marrow of patients with fatal sepsis suggests that activated macrophages play an important role in this disease setting.
Recently a distinct role for Wnt family members in inflammation and immunity has been recognized. The Drosophila Wnt protein family member WntD regulates the innate immune response to infection in the fly.14 In these studies, WntD expression is shown to be controlled by Toll signaling, a highly conserved pathway known to induce antimicrobial and inflammatory responses also in the human macrophage. Furthermore, WntD signaling in the fly was independent of the common β-catenin pathway, as it is the case in the inflammatory human macrophage system described herein. Moreover, WntD was identified as the first secreted regulator of Toll signaling in the fly. This is in line with an earlier study that described Wnt5A being secreted by activated antigen presenting cells and by inflammatory synoviocytes from rheumatoid arthritis joints.19 This was the first report of Wnt5A expression associated with an inflammation in humans. However, it became unclear in this study how Wnt5A expression was linked with inflammatory cytokine production, because the signaling of Wnt5A through FFZD5 was not delineated. More recently, Wnt5A expression is shown to be induced by mycobacterial cell wall components and endotoxin in human antigen presenting cells and is dependent on activation of the central inflammatory regulator NF-B.15 In this report it is clearly shown that Wnt5A expression required Toll-like receptor (TLR)2 and TLR4-dependent signaling. This finding is completely in line with the finding of TLR-dependent WntD expression in the fly, indicating that these pathways are linked together and are highly conserved throughout species. However, it was not elucidated whether activation of other TLRs induce Wnt5A or other Wnt homologues.15 Our study extends the idea that Wnt5A secretion constitutes a highly conserved response to inflammatory macrophage activation by demonstrating that Wnt5A mRNA is not only induced by LPS and the classical macrophage stimulator INF, but also by a representative array of TLR agonists targeting TLR 1-9.
After secretion, Wnt5A is proposed to act by ligation to its receptor FDZ5, which we and others have shown to be expressed in human macrophages.15 It was, however, not clear which pathway of Wnt5A signaling was involved in macrophages in the setting of inflammatory activation. Different signaling pathways may be triggered subsequently by Wnt5A/FDZ5. The canonical signaling pathway acts by enhancing the intracellular level of β-catenin. This canonical pathway is the most intensively studied pathway of Wnt action in cell development and differentiation. We were unable to detect any evidence for canonical signaling in our inflammatory activated macrophages. The noncanonical Wnt signaling pathway elucidated in the present study induced a rise in intracellular calcium levels and activated CaMKII, which, among other effects, leads to activation and nuclear translocation of the transcription factor NF-AT.20 Cell specific characteristics and the coreceptor environment in particular determine which of these pathways are activated on ligation of a frizzled receptor with its Wnt ligand. Ca2+ release and the associated phosphorylation of CamKII are extensively studied signaling events that are critically involved in macrophage activation.21,22 Our finding that recombinant Wnt5A increased phosphorylation of CamKII provides experimental evidence that Wnt5A is capable of activating the proinflammatory Ca2+/CamKII pathways in macrophages. This effect is completely abrogated by sFRP1, a soluble Wnt binding protein that specifically binds to and impairs Wnt5A interaction with its cognate cell surface receptor.18 This implies that a specific Wnt5A/FDZ5 interaction mediates the Wnt5A activity observed in our experiments and excludes nonspecific effects imparted by small molecular contaminants such as endotoxin. Again, this is fully in line with the findings of others that FDZ proteins are receptors for Wnt and that Wnt signaling is modulated by the specific cysteine-rich domain of soluble frizzled related peptides.18 Our finding, that sFRP1 also inhibited the LPS/IFN-–induced CamKII phosphorylation, implies a causal link between Wnt5A secretion triggered by inflammation and LPS/IFN-–induced macrophage activation. Again, this Wnt5A/FDZ5 mediated activation of the noncanonical signaling pathway may thus act as a positive regulatory mechanism that sustains and enhances inflammatory macrophage activation induced by exogenous proinflammatory agents. Our finding that Wnt5A activates the noncanonical signaling pathway in macrophages is compatible with its capacity to exert inflammatory effects in rheumatoid synoviocytes and in antigen presenting cells. Furthermore, treatment of macrophages with exogenous Wnt5A initiated secretion of inflammatory cytokines in our study. However, the subsequent observation that Wnt5A knockdown by siRNA significantly decreased the transcription and secretion of inflammatory cytokines and that inhibition of autocrine Wnt5A signaling by sFRP1 almost completely reversed LPS/INF-induced cytokine secretion suggests that Wnt5A is not just another inflammatory macrophage activator but also a pivotal regulator of macrophage activation during inflammation. In light of the findings in the septic fly model, where Wnt is critically involved in the control of infection, the findings of induced Wnt5A on mycobacterial infection of human monocytes, and the identification of Wnt5A in inflamed synoviocytes of rheumatoid arthirtis, our present findings suggest that Wnt5A is a highly specific autocrinous and paracrinous macrophage-derived effector molecule triggering inflammation through a well defined pathway. Therefore, our results suggest that the Wnt5A pathway is an attractive candidate target for therapeutic intervention in inflammatory diseases such as sepsis or rheumatoid arthritis. First, significant amounts of Wnt5A are secreted in septic patients. One could well assume from this finding and from the observations of Wnt5A being released by synoviocytes19 that Wnt5A is elevated also in the sera of rheumatoid arthritis patients. Second, interference with the Wnt5A signaling pathway acts at an early step in macrophage activation. The data from this study together with previous evidence17 suggests that Wnt5A signaling constitutes a nonredundant activation pathway, which might be indispensable for sustained inflammatory macrophage activation. Third, we show that expression of Wnt5A constitutes a highly conserved response to macrophage activation triggered by a wide array of ligands involved in initiation of systemic inflammation. This in turn implicates Wnt5A signaling in a final common pathway of macrophage activation. Fourth, the fact that Wnt5A is a secreted protein and that Wnt5A signaling involves classical receptor-ligand interactions raises the possibility of modulation of Wnt5A activity in vivo. Application of soluble Wnt5A neutralizing molecules, as applied in our work, thereby represents just one possibility for achieving in vivo suppression of inflammatory Wnt signaling. Although our results suggest that the development of Wnt antagonists might be a valuable strategy for controlling inflammation at one of its critical checkpoints, partial Wnt control during sepsis may yet be achieved by treatment with APC, which acts by downregulation of Wnt5A expression and thus by modulating inflammatory Wnt activity.
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Acknowledgments |
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We thank Nenad Blau, PhD, University Children’s Hospital of Zurich, for analysis of pteridines and creatinine, and Cheryl Pech, PhD, for her critical reading of the manuscript.
Sources of Funding
This study was supported by grant No. 3200B0-103945 from the Swiss National Science Foundation to G.S.
Disclosures
None.
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Footnotes |
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Original received June 2, 2007; final version accepted December 17, 2007.
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References |
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1. Angus DC, Linde-Zwirble WT, Lidicker J, Clermont G, Carcillo J, Pinsky MR. Epidemiology of severe sepsis in the United States: analysis of incidence, outcome, and associated costs of care. Crit Care Med. 2001; 29: 1303–1310.[CrossRef][Medline] [Order article via Infotrieve]
2. Brun-Buisson C, Doyon F, Carlet J, Dellamonica P, Gouin F, Lepoutre A, Mercier JC, Offenstadt G, Regnier B. Incidence, risk factors, and outcome of severe sepsis and septic shock inadults. A multicenter prospective study in intensive care units. French ICUGroup for Severe Sepsis. JAMA. 1995; 274: 968–974.
3. Yan SB, Helterbrand JD, Hartman DL, Wright TJ, Bernard GR. Low levels of protein C are associated with poor outcome in severe sepsis. Chest. 2001; 120: 915–922.[CrossRef][Medline] [Order article via Infotrieve]
4. Taylor FB Jr, Chang A, Esmon CT, D’Angelo A, Vigano-D’Angelo S, Blick KE. Protein C prevents the coagulopathic and lethal effects of Escherichia coli infusion in the baboon. J Clin Invest. 1987; 79: 918–925.[Medline] [Order article via Infotrieve]
5. Bernard GR, Vincent JL, Laterre PF, LaRosa SP, Dhainaut JF, Lopez-Rodriguez A, Steingrub JS, Garber GE, Helterbrand JD, Ely EW, Fisher CJ Jr. Recombinant human protein C Worldwide Evaluation in Severe Sepsis (PROWESS) study group. Efficacy and safety of recombinant human activated protein C for severe sepsis. N Engl J Med. 2001; 344: 699–709.
6. Esmon CT. The anticoagulant and anti-inflammatory roles of the protein C anticoagulant pathway. J Autoimmun. 2000; 15: 113–116.[CrossRef][Medline] [Order article via Infotrieve]
7. Joyce DE, Gelbert L, Ciaccia A, DeHoff B, Grinnell BW. Gene expression profile of antithrombotic protein C defines new mechanisms modulating inflammation and apoptosis. J Biol Chem. 2001; 276: 11199–11203.
8. Franscini N, Bachli EB, Blau N, Leikauf MS, Schaffner A, Schoedon G. Gene expression profiling of inflamed human endothelial cells and influence of activated protein C. Circulation. 2004; 110: 2903–2909.
9. Rice TW, Bernard GR. Advances in Sepsis Treatment. Curr Infect Dis Rep. 2004; 6: 354–360.[CrossRef][Medline] [Order article via Infotrieve]
10. Klingensmith J, Nusse R. Signaling by wingless in Drosophila. Dev Biol. 1994; 166: 396–414.[CrossRef][Medline] [Order article via Infotrieve]
11. Nusse R. Wnt signaling in disease and in development. Cell Res. 2005; 15: 28–32.[CrossRef][Medline] [Order article via Infotrieve]
12. Nelson WJ, Nusse R. Convergence of Wnt, beta-catenin, and cadherin pathways. Science. 2004; 303: 1483–1487.
13. Mosimann C, Hausmann G, Basler K. Parafibromin/Hyrax activates Wnt/Wg target gene transcription by direct association with beta-catenin/Armadillo. Cell. 2006; 125: 327–341.[CrossRef][Medline] [Order article via Infotrieve]
14. Gordon MD, Dionne MS, Schneider DS, Nusse R. WntD is a feedback inhibitor of Dorsal/NF-kappaB in Drosophila development and immunity. Nature. 2005; 437: 746–749.[CrossRef][Medline] [Order article via Infotrieve]
15. Blumenthal A, Ehlers S, Lauber J, Buer J, Lange C, Goldmann T, Heine H, Brandt E, Reiling N. The Wingless homolog WNT5A and its receptor Frizzled-5 regulate inflammatory responses of human mononuclear cells induced by microbial stimulation. Blood. 2006; 108: 965–973.
16. Mikels AJ, Nusse R. Purified Wnt5a Protein Activates or Inhibits β-Catenin–TCF Signaling Depending on Receptor Context. PLoS Biol. 2006; 4: e115.[CrossRef][Medline] [Order article via Infotrieve]
17. Schaer DJ, Schaer CA, Schoedon G, Imhof A, Kurrer MO. Hemophagocytic macrophages constitute a major compartment of heme oxygenase expression in sepsis. Eur J Haematol. 2006; 77: 432–436.[CrossRef][Medline] [Order article via Infotrieve]
18. Lin K, Wang S, Julius MA, Kitajewski J, Moos M Jr, Luyten FP. The cysteine-rich frizzled domain of Frzb-1 is required and sufficient for modulation of Wnt signaling. Proc Natl Acad Sci U S A. 1997; 94: 11196–11200.
19. Sen M, Lauterbach K, El-Gabalawy H, Firestein GS, Corr M, Carson DA. Expression and function of wingless and frizzled homologs in rheumatoid arthritis. Proc Natl Acad Sci U S A. 2000; 97: 2791–2796.
20. Kühl M. The Wnt/Calcium pathway: Biochemical mediators, tools and future requirements. Frontiers in Bioscience. 2004; 9: 967–974.[Medline] [Order article via Infotrieve]
21. Malik ZA, Iyer SS, Kusner DJ. Mycobacterium tuberculosis phagosomes exhibit altered calmodulin-dependent signal transduction: contribution to inhibition of phagosome-lysosome fusion and intracellular survival in human macrophages. J Immunol. 2001; 166: 3392–3401.
22. Mishra S, Mishra JP, Gee K, McManus DC, LaCasse EC, Kumar A. Distinct role of calmodulin and calmodulin-dependent protein kinase-II in lipopolysaccharide and tumor necrosis factor-{alpha}-mediated suppression of apoptosis and antiapoptotic C-IAP2 gene expression in human monocytic cells. J Biol Chem. 2005; 45: 37536–37546.
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