Publications by authors named "Colin de Haar"

32 Publications

Clinical Grade Production of Wilms' Tumor-1 Loaded Cord Blood-Derived Dendritic Cells to Prevent Relapse in Pediatric AML After Cord Blood Transplantation.

Front Immunol 2020 25;11:559152. Epub 2020 Sep 25.

Center for Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands.

Hematopoietic cell transplantation (HCT) is a last resort, potentially curative treatment option for pediatric patients with refractory acute myeloid leukemia (AML). Cord blood transplantation (CBT) results in less relapses and less graft-versus-host disease when compared to other sources. Nevertheless, still more than half of the children die from relapses. We therefore designed a strategy to prevent relapses by inducing anti-AML immunity after CBT, using a CB-derived dendritic cell (CBDC) vaccine generated from CD34+ CB cells from the same graft. We here describe the optimization and validation of good manufacturing practice (GMP)-grade production of the CBDC vaccine. We show the feasibility of expanding low amounts of CD34+ cells in a closed bag system to sufficient DCs per patient for at least three rounds of vaccinations. The CBDCs showed upregulated costimulatory molecules after maturation and showed enhanced CCR7-dependent migration toward CCL19 in a trans-well migrations assay. CBDCs expressed Wilms' tumor 1 (WT1) protein after electroporation with -mRNA, but were not as potent as CBDCs loaded with synthetic long peptides (peptivator). The WT1-peptivator loaded CBDCs were able to stimulate T-cells both in a mixed lymphocyte reaction as well as in an antigen-specific (autologous) setting. The autologous stimulated T-cells lysed not only the WT1+ cell line, but most importantly, also primary pediatric AML cells. Altogether, we provide a GMP-protocol of a highly mature CBDC vaccine, loaded with WT1 peptivator and able to stimulate autologous T-cells in an antigen-specific manner. Finally, these T-cells lysed primary pediatric AML demonstrating the competence of the CBDC vaccine strategy.
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http://dx.doi.org/10.3389/fimmu.2020.559152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7546401PMC
September 2020

Pregnane X receptor activation constrains mucosal NF-κB activity in active inflammatory bowel disease.

PLoS One 2019 3;14(10):e0221924. Epub 2019 Oct 3.

Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands.

Background: The Pregnane X Receptor (PXR) is a principal signal transducer in mucosal responses to xenobiotic stress. It is well-recognized that inflammatory bowel disease is accompanied by xenobiotic stress, but the importance of the PXR in limiting inflammatory responses in inflammatory bowel disease remains obscure at best.

Methods: We stimulate a total of 106 colonic biopsies from 19 Crohn's disease patients with active disease, 36 colonic biopsies from 8 control patients, colonic organoids and various cell culture models (either proficient or genetically deficient with respect to PXR) in vitro with the PXR ligand rifampicin or vehicle. Effects on NF-κB activity are assessed by measuring interleukin-8 (IL-8) and interleukin-1ß (IL-1ß) mRNA levels by qPCR and in cell culture models by NF-κB reporter-driven luciferase activity and Western blot for signal transduction elements.

Results: We observe a strict inverse correlation between colonic epithelial PXR levels and NF-κB target gene expression in colonic biopsies from Crohn's disease patients. PXR, activated by rifampicin, is rate-limiting for mucosal NF-κB activation in IBD. The correlation between colonic epithelial PXR levels and NF-κB target gene expression was also observed in intestinal organoids system. Furthermore, in preclinical in vitro models of intestinal inflammation, including intestinal organoids, genetic inactivation of PXR unleashes NF-κB-dependent signal transduction whereas conversely NF-κB signaling reduces levels of PXR expression.

Conclusions: Our data indicate that the PXR is a major and clinically relevant antagonist of NF-κB activity in the intestinal epithelial compartment during inflammatory bowel disease.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0221924PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6776398PMC
March 2020

Adipocytes harbor a glucosylceramide biosynthesis pathway involved in iNKT cell activation.

Biochim Biophys Acta Mol Cell Biol Lipids 2019 08 30;1864(8):1157-1167. Epub 2019 Apr 30.

Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, the Netherlands. Electronic address:

Background: Natural killer T (NKT) cells in adipose tissue (AT) contribute to whole body energy homeostasis.

Results: Inhibition of the glucosylceramide synthesis in adipocytes impairs iNKT cell activity.

Conclusion: Glucosylceramide biosynthesis pathway is important for endogenous lipid antigen activation of iNKT cells in adipocytes.

Significance: Unraveling adipocyte-iNKT cell communication may help to fight obesity-induced AT dysfunction. Overproduction and/or accumulation of ceramide and ceramide metabolites, including glucosylceramides, can lead to insulin resistance. However, glucosylceramides also fulfill important physiological functions. They are presented by antigen presenting cells (APC) as endogenous lipid antigens via CD1d to activate a unique lymphocyte subspecies, the CD1d-restricted invariant (i) natural killer T (NKT) cells. Recently, adipocytes have emerged as lipid APC that can activate adipose tissue-resident iNKT cells and thereby contribute to whole body energy homeostasis. Here we investigate the role of the glucosylceramide biosynthesis pathway in the activation of iNKT cells by adipocytes. UDP-glucose ceramide glucosyltransferase (Ugcg), the first rate limiting step in the glucosylceramide biosynthesis pathway, was inhibited via chemical compounds and shRNA knockdown in vivo and in vitro. β-1,4-Galactosyltransferase (B4Galt) 5 and 6, enzymes that convert glucosylceramides into potentially inactive lactosylceramides, were subjected to shRNA knock down. Subsequently, (pre)adipocyte cell lines were tested in co-culture experiments with iNKT cells (IFNγ and IL4 secretion). Inhibition of Ugcg activity shows that it regulates presentation of a considerable fraction of lipid self-antigens in adipocytes. Furthermore, reduced expression levels of either B4Galt5 or -6, indicate that B4Galt5 is dominant in the production of cellular lactosylceramides, but that inhibition of either enzyme results in increased iNKT cell activation. Additionally, in vivo inhibition of Ugcg by the aminosugar AMP-DNM results in decreased iNKT cell effector function in adipose tissue. Inhibition of endogenous glucosylceramide production results in decreased iNKT cells activity and cytokine production, underscoring the role of this biosynthetic pathway in lipid self-antigen presentation by adipocytes.
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http://dx.doi.org/10.1016/j.bbalip.2019.04.016DOI Listing
August 2019

Cord-Blood-Stem-Cell-Derived Conventional Dendritic Cells Specifically Originate from CD115-Expressing Precursors.

Cancers (Basel) 2019 Feb 5;11(2). Epub 2019 Feb 5.

Laboratory of Translational Immunology, University Medical Center Utrecht, 3584 XC Utrecht, The Netherlands.

Dendritic cells (DCs) are professional antigen-presenting cells which instruct both the innate and adaptive immune systems. Once mature, they have the capacity to activate and prime naïve T cells for recognition and eradication of pathogens and tumor cells. These characteristics make them excellent candidates for vaccination strategies. Most DC vaccines have been generated from ex vivo culture of monocytes (mo). The use of mo-DCs as vaccines to induce adaptive immunity against cancer has resulted in clinical responses but, overall, treatment success is limited. The application of primary DCs or DCs generated from CD34⁺ stem cells have been suggested to improve clinical efficacy. Cord blood (CB) is a particularly rich source of CD34⁺ stem cells for the generation of DCs, but the dynamics and plasticity of the specific DC lineage development are poorly understood. Using flow sorting of DC progenitors from CB cultures and subsequent RNA sequencing, we found that CB-derived DCs (CB-DCs) exclusively originate from CD115⁺-expressing progenitors. Gene set enrichment analysis displayed an enriched conventional DC profile within the CD115-derived DCs compared with CB mo-DCs. Functional assays demonstrated that these DCs matured and migrated upon good manufacturing practice (GMP)-grade stimulation and possessed a high capacity to activate tumor-antigen-specific T cells. In this study, we developed a culture protocol to generate conventional DCs from CB-derived stem cells in sufficient numbers for vaccination strategies. The discovery of a committed DC precursor in CB-derived stem cell cultures further enables utilization of conventional DC-based vaccines to provide powerful antitumor activity and long-term memory immunity.
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http://dx.doi.org/10.3390/cancers11020181DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6406310PMC
February 2019

Analysis of SHIP1 expression and activity in Crohn's disease patients.

PLoS One 2017 2;12(8):e0182308. Epub 2017 Aug 2.

Department of Gastroenterology and Hepatology, Erasmus MC, University Medical Center Rotterdam, 's Gravendijkwal 230, Rotterdam, the Netherlands.

Background: SH2 domain containing inositol-5-phosphatase (SHIP1) is an important modulator of innate and adaptive immunity. In mice, loss of SHIP1 provokes severe ileitis resembling Crohn's disease (CD), as a result of deregulated immune responses, altered cytokine production and intestinal fibrosis. Recently, SHIP1 activity was shown to be correlated to the presence of a CD-associated single nucleotide polymorphism in ATG16L1. Here, we studied SHIP1 activity and expression in an adult cohort of CD patients.

Methods: SHIP1 activity, protein and mRNA expression in peripheral blood mononuclear cells from CD patients in clinical remission were determined by Malachite green assay, Western blotting and qRT-PCR respectively. Genomic DNA was genotyped for ATG16L1 rs2241880.

Results: SHIP1 protein levels are profoundly diminished in a subset of patients; however, SHIP1 activity and expression are not correlated to ATG16L1 SNP status in this adult cohort.

Conclusions: Aberrant SHIP1 activity can contribute to disease in a subset of adult CD patients, and warrants further investigation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0182308PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5540589PMC
September 2017

Fatigue in patients with inflammatory bowel disease is associated with distinct differences in immune parameters.

Clin Exp Gastroenterol 2017 2;10:83-90. Epub 2017 May 2.

Department of Gastroenterology and Hepatology, Erasmus MC, Rotterdam.

Background: Although it is well recognized that fatigue is an important problem in many of the quiescent inflammatory bowel disease (IBD) patients, it is unknown whether the immune status is different in fatigued versus non-fatigued patients. In this study, we contrasted various characteristics of the immune system in fatigued against non-fatigued patients with IBD in clinical remission.

Patients And Methods: Patients with IBD in clinical remission were phenotyped according to the Montreal classification, and the checklist individual strength-fatigue (CIS-fatigue) was used to assess fatigue (CIS-fatigue ≥ 35). Flow cytometry on peripheral blood samples was used to investigate differences in leukocyte subsets. The expression of various cytokines was determined in stimulated whole blood and serum samples using enzyme-linked immunosorbent assay. Differences between fatigued and non-fatigued patients with IBD were assessed.

Results: In total, 55 patients were included in the fatigue group (FG) and 29 patients in the non-fatigue group (NFG). No differences in demographic and clinical characteristics were observed between the groups. Flow cytometry data showed a significantly lower percentage of monocytes ( = 0.011) and a higher percentage of memory T-cells ( = 0.005) and neutrophils ( = 0.033) in the FG compared with the NFG. Whole blood stimulation showed increased TNF-α ( = 0.022) and IFN-γ ( = 0.047) in the FG. The median serum level was significantly higher for IL-12 ( < 0.001) and IL-10 ( = 0.005) and lower for IL-6 ( = 0.002) in the FG compared with NFG.

Conclusion: Significant differences in immune profile between fatigued and non-fatigued patients with IBD in clinical remission were found, which point out to a chronically active and Th1-skewed immune system in patients with fatigue. Whether these immune differences are directly involved in the fatigue complaints via immune-to-brain communication pathways remains to be determined. As such, further exploration of the underlying immune effects associated with fatigue is warranted to determine potential treatment options.
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http://dx.doi.org/10.2147/CEG.S123942DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5422327PMC
May 2017

Generation of a cord blood-derived Wilms Tumor 1 dendritic cell vaccine for AML patients treated with allogeneic cord blood transplantation.

Oncoimmunology 2015 Nov 27;4(11):e1023973. Epub 2015 May 27.

U-DANCE; Laboratory for Translational Immunology; UMC Utrecht ; Utrecht, The Netherlands ; U-DAIR; LTI; UMC Utrecht ; Utrecht, The Netherlands.

The poor survival rates of refractory/relapsed acute myeloid leukemia (AML) patients after haematopoietic cell transplantation (HCT) requires the development of additional immune therapeutic strategies. As the elicitation of tumor-antigen specific cytotoxic T lymphocytes (CTLs) is associated with reduced relapses and enhanced survival, enhanced priming of these CTLs using an anti-AML vaccine may result in long-term immunity against AML. Cord blood (CB), as allogeneic HCT source, may provide a unique setting for such post-HCT vaccination, considering its enhanced graft-versus-leukemia (GvL) effects and population of highly responsive naïve T cells. It is our goal to develop a powerful and safe immune therapeutic strategy composed of CB-HCT followed by vaccination with CB CD34-derived dendritic cells (DCs) presenting the oncoprotein Wilms Tumor-1 (WT1), which is expressed in AML-blasts in the majority of patients. Here, we describe the optimization of a clinically applicable DC culture protocol. This two-step protocol consisting of an expansion phase followed by the differentiation toward DCs, enables us to generate sufficient cord blood-derived DCs (CBDCs) in the clinical setting. At the end of the culture, the CBDCs exhibit a mature surface phenotype, are able to migrate, express tumor antigen (WT1) after electroporation with mRNA encoding the full-length WT1 protein, and stimulate WT1-specific T cells.
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http://dx.doi.org/10.1080/2162402X.2015.1023973DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4589057PMC
November 2015

CD1d-mediated presentation of endogenous lipid antigens by adipocytes requires microsomal triglyceride transfer protein.

J Biol Chem 2014 Aug 25;289(32):22128-39. Epub 2014 Jun 25.

From the Molecular Cancer Research, Center for Molecular Medicine and

Obesity-induced adipose tissue (AT) dysfunction results in a chronic low-grade inflammation that predisposes to the development of insulin resistance and type 2 diabetes. During the development of obesity, the AT-resident immune cell profile alters to create a pro-inflammatory state. Very recently, CD1d-restricted invariant (i) natural killer T (NKT) cells, a unique subset of lymphocytes that are reactive to so called lipid antigens, were implicated in AT homeostasis. Interestingly, recent data also suggest that human and mouse adipocytes can present such lipid antigens to iNKT cells in a CD1d-dependent fashion, but little is known about the lipid antigen presentation machinery in adipocytes. Here we show that CD1d, as well as the lipid antigen loading machinery genes pro-saposin (Psap), Niemann Pick type C2 (Npc2), α-galactosidase (Gla), are up-regulated in early adipogenesis, and are transcriptionally controlled by CCAAT/enhancer-binding protein (C/EBP)-β and -δ. Moreover, adipocyte-induced Th1 and Th2 cytokine release by iNKT cells also occurred in the absence of exogenous ligands, suggesting the display of endogenous lipid antigen-D1d complexes by 3T3-L1 adipocytes. Furthermore, we identified microsomal triglyceride transfer protein, which we show is also under the transcriptional regulation of C/EBPβ and -δ, as a novel player in the presentation of endogenous lipid antigens by adipocytes. Overall, our findings indicate that adipocytes can function as non-professional lipid antigen presenting cells, which may present an important aspect of adipocyte-immune cell communication in the regulation of whole body energy metabolism and immune homeostasis.
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http://dx.doi.org/10.1074/jbc.M114.551242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4139226PMC
August 2014

Dendritic Cell Therapy in an Allogeneic-Hematopoietic Cell Transplantation Setting: An Effective Strategy toward Better Disease Control?

Front Immunol 2014 19;5:218. Epub 2014 May 19.

Utrecht - Dendritic cells AgaiNst CancEr (U-DANCE), Laboratory of Translational Immunology, Department of Immunology, University Medical Centre Utrecht , Utrecht , Netherlands ; Pediatric Blood and Marrow Transplantation Program, Department of Immunology, University Medical Centre Utrecht , Utrecht , Netherlands.

Hematopoietic cell transplantation (HCT) is a last treatment resort and only potentially curative treatment option for several hematological malignancies resistant to chemotherapy. The induction of profound immune regulation after allogeneic HCT is imperative to prevent graft-versus-host reactions and, at the same time, allow protective immune responses against pathogens and against tumor cells. Dendritic cells (DCs) are highly specialized antigen-presenting cells that are essential in regulating this balance and are of major interest as a tool to modulate immune responses in the complex and challenging phase of immune reconstitution early after allo-HCT. This review focuses on the use of DC vaccination to prevent cancer relapses early after allo-HCT. It describes the role of host and donor-DCs, various vaccination strategies, different DC subsets, antigen loading, DC maturation/activation, and injection sites and dose. At last, clinical trials using DC vaccination post-allo-HCT and the future perspectives of DC vaccination in combination with other cancer immunotherapies are discussed.
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http://dx.doi.org/10.3389/fimmu.2014.00218DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4032952PMC
June 2014

Suppression of p21Rac signaling and increased innate immunity mediate remission in Crohn's disease.

Sci Transl Med 2014 Apr;6(233):233ra53

Department of Cell Biology, University Medical Center Groningen, University of Groningen, Deusinglaan 1, NL-9713 AV Groningen, the Netherlands.

In inflammatory bowel disease (IBD), large areas of apparently healthy mucosa lie adjacent to ulcerated intestine. Knowledge of the mechanisms that maintain remission in an otherwise inflamed intestine could provide important clues to the pathogenesis of this disease and provide rationale for clinical treatment strategies. We used kinome profiling to generate comprehensive descriptions of signal transduction pathways in inflamed and noninflamed colonic mucosa in a cohort of IBD patients, and compared the results to non-IBD controls. We observed that p21Rac1 guanosine triphosphatase (GTPase) signaling was strongly suppressed in noninflamed colonic mucosa in IBD. This suppression was due to both reduced guanine nucleotide exchange factor activity and increased intrinsic GTPase activity. Pharmacological p21Rac1 inhibition correlated with clinical improvement in IBD, and mechanistically unrelated pharmacological p21Rac1 inhibitors increased innate immune functions such as phagocytosis, bacterial killing, and interleukin-8 production in healthy controls and patients. Thus, suppression of p21Rac activity assists innate immunity in bactericidal activity and may induce remission in IBD.
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http://dx.doi.org/10.1126/scitranslmed.3006763DOI Listing
April 2014

Genomic ATG16L1 risk allele-restricted Paneth cell ER stress in quiescent Crohn's disease.

Gut 2014 Jul 20;63(7):1081-91. Epub 2013 Aug 20.

Department Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.

Objective: Although genome wide association studies have partly uncovered the genetic basis of Crohn's disease (CD), it remains a challenge to link genetic polymorphisms to functional intestinal phenotypes. Paneth cells are specialised antimicrobial epithelial cells localised to the small-intestinal crypt-base. Here, we investigate whether genomic variations in ATG16L1 affect Paneth cell function.

Design: Genomic variation of ATG16L1 (T300A, rs2241880) was determined in DNA from 78 patients with CD and 12 healthy controls. Paraffin-embedded ileal biopsies from patients with genotype AA (n=17), GA (n=38) and patients with the GG allele (n=23) were stained for GRP78, phospho-EIF2α, lysozyme, cleaved-caspase 3, phosphohistone H3, phospho-IκB, p65, phospho-p38MAPK and PHLDA1. Microbial composition of biopsies was assessed by PCR. Disease phenotype was scored.

Results: In patients with quiescent disease but with an ATG16L1 risk allele, the endoplasmic reticulum (ER) stress markers GRP78 and pEIF2α were highly expressed in Paneth cells. Other CD risk gene variations did not correlate with Paneth cell ER stress. Functionally, patients with ER-stressed Paneth cells showed no changes in intestinal epithelial cells proliferation or apoptosis, Paneth cell or stem cell numbers, p65, phospho-IκB and phospho-p38 staining. However, a significantly increased presence of adherent-invasive Escherichia coli was observed in biopsies from patients with ER-stressed Paneth cells. Phenotypically, patients with GRP78 positive Paneth cells have relatively less colonic disease over ileal disease (-21%, p=0.04), more fistulas (+21%, p=0.05) and an increased need for intestinal surgery (+38%, p=0.002).

Conclusions: The ATG16L1 T300A polymorphism defines a specific subtype of patients with CD, characterised by Paneth cell ER stress even during quiescent disease. Paneth cell ER stress correlates with bacterial persistence, and is thus likely to modulate antimicrobial functionality of this cell type in patients with CD.
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http://dx.doi.org/10.1136/gutjnl-2012-303527DOI Listing
July 2014

The cell biology of the intestinal epithelium and its relation to inflammatory bowel disease.

Int J Biochem Cell Biol 2013 Apr 3;45(4):798-806. Epub 2013 Jan 3.

Erasmus MC - University Medical Centre Rotterdam, Department Gastroenterology and Hepatology, The Netherlands.

The epithelial layer of our intestines must meet two opposing requirements. On one hand it must allow for efficient uptake of nutrients and fluids, on the other hand it is a vital defence barrier between the milieu interior and the milieu exterior. In contrast to the lung that by virtue of cilia movement is kept virtually sterile, the gut epithelium is confronted by a stupendous microbiological load and a substantial xenobiotic challenge. The efficiency by which our intestinal epithelium manages to deal with the challenge of efficient nutrient absorption while simultaneously fulfilling its barrier function is testimony to what the forces of evolution can accomplish. Importantly, our understanding as to how our gut epithelial compartment manages this balancing act is now rapidly emerging, answering one of the oldest questions in cell biology. Importantly, when aberrations in this balance occur, for instance as a consequence genetic polymorphisms, increased propensity to develop chronic inflammation and inflammatory bowel disease is the result. Thus the knowledge on intestinal cell biology and biochemistry is not only of academic interest but may also aid design of novel avenues for the rational treatment of mucosal disease.
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http://dx.doi.org/10.1016/j.biocel.2012.12.020DOI Listing
April 2013

STAT1, STAT6 and adenosine 3',5'-cyclic monophosphate (cAMP) signaling drive SOCS3 expression in inactive ulcerative colitis.

Mol Med 2012 Dec 20;18:1412-9. Epub 2012 Dec 20.

Department of Gastroenterology and Hepatology, Erasmus MC, Rotterdam, Netherlands.

Ulcerative colitis (UC) is a chronic disease associated with long periods of quiescent disease followed by fulminant exacerbation. Imminent relapse in UC is associated with high mucosal expression of suppressor of cytokine signaling 3 (SOCS3); hence, knowledge of the mechanisms driving mucosal SOCS3 expression may provide important clues as to rational therapy. Thus, here we aim to characterize the molecular forces driving SOCS3 expression in the mucosal compartment, focusing on druggable pathways. The colon epithelial cell line Caco-2 was stimulated with interferon (IFN)-γ, interleukin (IL)-4 or prostaglandin E(2) (PGE(2)) to allow correlations between SOCS3 expression with signal transducer and activator of transcription 1 (STAT1), STAT6 and adenosine 3',5'-cyclic monophosphate (cAMP) signaling, respectively. The physiological relevance of the findings obtained was assessed by immunohistochemical staining for the activated forms of STAT1, STAT6, protein kinase A (PKA)-Cγ and cAMP response element-binding protein (CREB) in biopsies from inactive UC patients and controls. Stimulation with IFN-γ, IL-4 or PGE(2) induced activation of STAT1, STAT6 and cAMP, respectively, in colonic cells, without any signs of concomitant STAT3 activation. Forced activation of all these signaling pathways was sufficient for SOCS3 expression. Biopsies from patients with inactive UC showed significant increase of phosphorylated STAT1 (p-STAT1) (p < 0.0001), p-STAT6 (p = 0.0001), p-PKA-Cγ (p = 0.0003) and p-CREB (p = 0.0025) expression compared with controls. STAT3-independent SOCS3 induction in inactive UC involves multiple proinflammatory signaling pathways and contradicts the usefulness of pathway-specific antiinflammatory drugs for preventing relapse. Our findings suggest that broad-spectrum antiinflammatory drugs are essential to counteract increases in SOCS3 expression and exacerbation of disease. Our results highlight the multifactorial nature of the factors that cause exacerbation in UC.
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http://dx.doi.org/10.2119/molmed.2012.00277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3533641PMC
December 2012

CD64 distinguishes macrophages from dendritic cells in the gut and reveals the Th1-inducing role of mesenteric lymph node macrophages during colitis.

Eur J Immunol 2012 Dec 17;42(12):3150-66. Epub 2012 Oct 17.

Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Marseille, France.

Dendritic cells (DCs) and monocyte-derived macrophages (MΦs) are key components of intestinal immunity. However, the lack of surface markers differentiating MΦs from DCs has hampered understanding of their respective functions. Here, we demonstrate that, using CD64 expression, MΦs can be distinguished from DCs in the intestine of both mice and humans. On that basis, we revisit the phenotype of intestinal DCs in the absence of contaminating MΦs and we delineate a developmental pathway in the healthy intestine that leads from newly extravasated Ly-6C(hi) monocytes to intestinal MΦs. We determine how inflammation impacts this pathway and show that T cell-mediated colitis is associated with massive recruitment of monocytes to the intestine and the mesenteric lymph node (MLN). There, these monocytes differentiate into inflammatory MΦs endowed with phagocytic activity and the ability to produce inducible nitric oxide synthase. In the MLNs, inflammatory MΦs are located in the T-cell zone and trigger the induction of proinflammatory T cells. Finally, T cell-mediated colitis develops irrespective of intestinal DC migration, an unexpected finding supporting an important role for MLN-resident inflammatory MΦs in the etiology of T cell-mediated colitis.
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http://dx.doi.org/10.1002/eji.201242847DOI Listing
December 2012

IL-6-induced DNMT1 activity mediates SOCS3 promoter hypermethylation in ulcerative colitis-related colorectal cancer.

Carcinogenesis 2012 Oct 27;33(10):1889-96. Epub 2012 Jun 27.

Department of Gastroenterology and Hepatology, Erasmus Medical Center, Rotterdam, Netherlands.

Ulcerative colitis (UC) is associated with a high risk of developing colorectal cancer (CRC). The mechanisms by which chronic inflammatory responses in the colon may promote CRC remain only partially understood, but may involve reduced negative regulation of interleukin (IL)-6 signaling towards signal transducer and activator of transcription 3 activation through the loss of SOCS3 expression, unleashing the full carcinogenic potential of this transcription factor. Thus, we analyzed SOCS3 expression in the colon of healthy controls, as well as in a cohort of UC patients with varying degrees of dysplasia. We observe that the loss of epithelial SOCS3 expression delimits the areas subject to dysplasia in UC, suggesting an important tumour-suppressive role of SOCS3 downregulation, early in the transformation process. Importantly, methylation of the SOCS3 promotor appears to constitute an important regulatory mechanism for colonic SOCS3 expression as SOCS3 methylation status in CRC cells correlates with a disability to upregulate SOCS3 upon IL-6 stimulation, whereas forced demethylation using 5-aza-2'-deoxycytidine restores SOCS3 expression and inhibits IL-6-induced p-signal transducer and activator of transcription 3 activation and proliferation. Expression of the DNA methyltransferase gene DMNT1 is prominent in dysplastic cells and correlates with low or absent SOCS3 expression. Thus, induction of DNMT1 expression in the chronically inflamed colon may release IL-6 signaling towards signal transducer and activator of transcription 3 from inhibition through SOCS3 increasing the propensity to malignant transformation. Hence, DNMT1 emerges as a rational target in preventive strategies aimed at counteracting UC-CRC.
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http://dx.doi.org/10.1093/carcin/bgs214DOI Listing
October 2012

SOCS3 in immune regulation of inflammatory bowel disease and inflammatory bowel disease-related cancer.

Cytokine Growth Factor Rev 2012 Jun 15;23(3):127-38. Epub 2012 May 15.

Department of Gastroenterology and Hepatology, Erasmus Medical Center, Rotterdam, The Netherlands.

Inflammatory bowel disease (IBD) has unclear pathogenesis and it is related to the increasing risk of developing colorectal cancer (CRC). Recent studies have uncovered the molecular mechanism of intracellular signaling pathways of inflammatory cytokines such as tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-6. The major transcription factors including STAT3 have been shown to play a major role in transmitting inflammatory cytokine signals to the nucleus. The suppressors of cytokine signaling (SOCS) 3 protein is the key physiological regulators of cytokine-mediated STAT3 signaling. As such it influences the development of inflammatory and malignant disorders like this associated with IBD. Here we review the complex function of SOCS3 in innate and adaptive immunity, different cell types (macrophages, neutrophils, dendritic cells, B cells, T cells and intestinal epithelial cells) and the role of SOCS3 on the pathogenesis of inflammatory bowel disease (IBD) and IBD-related cancer. Finally, we explore how this knowledge may open novel avenues for the rational treatment of IBD and IBD-related cancer.
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http://dx.doi.org/10.1016/j.cytogfr.2012.04.005DOI Listing
June 2012

Increased suppressor of cytokine signaling-3 expression predicts mucosal relapse in ulcerative colitis.

Inflamm Bowel Dis 2013 Jan;19(1):132-40

Department of Gastroenterology and Hepatology, Erasmus Medical Center, Rotterdam, Netherlands.

Background: Most biomarkers predicting mucosal relapse of ulcerative colitis (UC) patients in clinical remission represent low levels of mucosal inflammation. Since SOCS3 expression may increase the vulnerability of intestinal epithelial cells (IECs) to various insults, we investigated whether its expression predicts mucosal relapse in UC patients in clinical remission without any signs of mucosal inflammation.

Methods: UC patients (n = 32) in clinical, endoscopic, and histological remission were followed up for 9 years. IEC expression of SOCS3, p-STAT3, and p-STAT1 were assessed with biopsies from the baseline colonoscopy, last colonoscopy before relapse, and colonoscopy at relapse. Clinical data, endoscopy, and histology reports were collected from patient charts.

Results: Twenty-six (81%) patients had histological relapse, 19 (59%) developed an endoscopic relapse, and 17 (53%) had a clinical relapse during follow-up. SOCS3 expression at first colonoscopy during remission correlated with shorter time to histological, endoscopic, and clinical relapse. SOCS3 expression was increased at the last colonoscopy before relapse, approaching relapse levels, whereas p-STAT3 expression was low during the entire remission. A positive correlation between IEC SOCS3 and its inducer p-STAT1 was shown.

Conclusions: SOCS3 IEC expression during remission may be useful in predicting mucosal relapse in patients without any signs of mucosal inflammation. These data strengthen our hypothesis that SOCS3 contributes to enhanced vulnerability of IEC during remission. Thus, SOCS3 levels during remission may function as a therapeutic target for clinical monitoring and early induction of mucosal healing.
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http://dx.doi.org/10.1002/ibd.22992DOI Listing
January 2013

Results of the 2nd scientific workshop of the ECCO (III): basic mechanisms of intestinal healing.

J Crohns Colitis 2012 Apr 11;6(3):373-85. Epub 2011 Dec 11.

Department of Gastroenterology & Hepatology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, USA.

The second scientific workshop of the European Crohn's and Colitis Organization (ECCO) focused on the relevance of intestinal healing for the disease course of inflammatory bowel disease (IBD). The objective was to better understand basic mechanisms, markers for disease prediction, detection and monitoring of intestinal healing, impact of intestinal healing on the disease course of IBD as well as therapeutic strategies. The results of this workshop are presented in four separate manuscripts. This section describes basic mechanisms of intestinal healing, identifies open questions in the field and provides a framework for future studies.
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http://dx.doi.org/10.1016/j.crohns.2011.11.009DOI Listing
April 2012

New insights into the role of STAT3 in IBD.

Inflamm Bowel Dis 2012 Jun 12;18(6):1177-83. Epub 2011 Oct 12.

Department of Gastroenterology and Hepatology, Erasmus Medical Center, Rotterdam, Netherlands.

Although it is clear that inflammatory bowel disease (IBD) involves an inappropriate immune response to floral components, the molecular determinants that mediate the gene transcription underlying and aggravating disease remain poorly understood. There is building momentum, however, that implicates differential regulation of the signal transducer and activator of transcription (STAT) 3 as an important factor in mediating pathogenic gene transcription in IBD, and this notion was reinforced by studies presented at the recent 2011 Digestive Disease Week (DDW) conference in Chicago. In the present report we integrate the existing body of literature with the novel data presented at this meeting to present a kaleidoscopic scheme so as to provide further insight into the role of STAT3 in IBD. A genetic propensity to its overactivation in the monocyte and epithelial compartment compromises the innate defense to allow low-level bacterial infection to fester and eventually initiate disease. The subsequent STAT3 activation in various relevant mucosal immune compartments, in particular epithelial cell proliferation and survival, and the function of the regulatory T cells and Th17 cells allow the mucosal immune system to fight the infection and return to steady state. As such, the action of STAT3 in IBD is highly context-dependent but always important.
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http://dx.doi.org/10.1002/ibd.21884DOI Listing
June 2012

Absence of ABCG2-mediated mucosal detoxification in patients with active inflammatory bowel disease is due to impeded protein folding.

Biochem J 2012 Jan;441(1):87-93

Department of Gastroenterology and Hepatology, Erasmus MC University Medical Centre Rotterdam, 3015 CE Rotterdam, The Netherlands.

Xenotoxic damage in inflammatory diseases, including IBD (inflammatory bowel disease), is compounded by reduced activity of the xenobiotic transporter ABCG2 (ATP-binding-cassette G2) during the inflammatory state. An association between the activation of the unfolded protein response pathway and inflammation prompted us to investigate the possibility that reduced ABCG2 activity is causally linked to this response. To this end, we correlated expression of ABCG2 and the unfolded protein response marker GRP78 (glucose-regulated protein of 78 kDa) in colon biopsies from healthy individuals (n=9) and patients with inactive (n=67) or active (n=55) IBD, ischaemic colitis (n=10) or infectious colitis (n=14). In addition, tissue specimens throughout the small bowel from healthy individuals (n=27) and from patients with inactive (n=9) or active (n=25) Crohn's disease were co-stained for ABCG2 and GRP78. In all biopsies from patients with active inflammation, irrespective of the underlying disease, an absolute negative correlation was observed between epithelial ABCG2 expression and GRP78 expression, suggesting that inflammation-dependent activation of the unfolded protein response is responsible for suppression of ABCG2 function. The link between the unfolded protein response and functional ABCG2 expression was further corroborated by live imaging of ABCG2-expressing cells, which showed that various inflammatory mediators, including nitric oxide, activate the unfolded protein response and concomitantly reduce plasma membrane localization as well as transport function of ABCG2. Thus a novel mechanism for explaining xenobiotic stress during inflammation emerges in which intestinal inflammation activates the unfolded protein response, in turn abrogating defences against xenobiotic challenge by impairing ABCG2 expression and function.
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http://dx.doi.org/10.1042/BJ20111281DOI Listing
January 2012

Impeded protein folding and function in active inflammatory bowel disease.

Biochem Soc Trans 2011 Aug;39(4):1107-11

Erasmus MC-University Medical Centre Rotterdam, Department of Gastroenterology and Hepatology, 's-Gravendijkwal 230, Room L-462, 3015 CE Rotterdam, The Netherlands.

The intestinal tract is covered by a total of 300 square metres of IECs (intestinal epithelial cells) that covers the entire intestinal mucosa. For protection against luminal xenobiotics, pathogens and commensal microbes, these IECs are equipped with membrane-bound transporters as well as the ability to secrete specific protective proteins. In patients with active IBD (inflammatory bowel disease), the expression of these proteins, e.g. ABC (ATP-binding cassette) transporters such as ABCG2 (ABC transporter G2) and defensins, is decreased, thereby limiting the protection against various luminal threats. Correct ER (endoplasmic reticulum)-dependent protein folding is essential for the localization and function of secreted and membrane-bound proteins. Inflammatory triggers, such as cytokines and nitric oxide, can impede protein folding, which causes the accumulation of unfolded proteins inside the ER. As a result, the unfolded protein response is activated which can lead to a cellular process named ER stress. The protein folding impairment affects the function and localization of several proteins, including those involved in protection against xenobiotics. In the present review, we discuss the possible inflammatory pathways affecting protein folding and eventually leading to IEC malfunction in patients with active IBD.
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http://dx.doi.org/10.1042/BST0391107DOI Listing
August 2011

Neonatal Fc receptor for IgG (FcRn) regulates cross-presentation of IgG immune complexes by CD8-CD11b+ dendritic cells.

Proc Natl Acad Sci U S A 2011 Jun 31;108(24):9927-32. Epub 2011 May 31.

Division of Gastroenterology, Brigham and Women's Hospital, Boston, MA 02115, USA.

Cross-presentation of IgG-containing immune complexes (ICs) is an important means by which dendritic cells (DCs) activate CD8(+) T cells, yet it proceeds by an incompletely understood mechanism. We show that monocyte-derived CD8(-)CD11b(+) DCs require the neonatal Fc receptor for IgG (FcRn) to conduct cross-presentation of IgG ICs. Consequently, in the absence of FcRn, Fcγ receptor (FcγR)-mediated antigen uptake fails to initiate cross-presentation. FcRn is shown to regulate the intracellular sorting of IgG ICs to the proper destination for such cross-presentation to occur. We demonstrate that FcRn traps antigen and protects it from degradation within an acidic loading compartment in association with the rapid recruitment of key components of the phagosome-to-cytosol cross-presentation machinery. This unique mechanism thus enables cross-presentation to evolve from an atypically acidic loading compartment. FcRn-driven cross-presentation is further shown to control cross-priming of CD8(+) T-cell responses in vivo such that during chronic inflammation, FcRn deficiency results in inadequate induction of CD8(+) T cells. These studies thus demonstrate that cross-presentation in CD8(-)CD11b(+) DCs requires a two-step mechanism that involves FcγR-mediated internalization and FcRn-directed intracellular sorting of IgG ICs. Given the centrality of FcRn in controlling cross-presentation, these studies lay the foundation for a unique means to therapeutically manipulate CD8(+) T-cell responses.
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http://dx.doi.org/10.1073/pnas.1019037108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3116387PMC
June 2011

Role of defective autophagia and the intestinal flora in Crohn disease.

Self Nonself 2010 Oct-Dec;1(4):323-327

Department of Gastroenterology and Hepatology; Erasmus MC; University Medical Center Rotterdam; Rotterdam, The Netherlands.

The precise mechanisms underlying the development of Crohn disease (CD) remain controversial, but sufficient data have been collected to suggest that an uncontrolled immune response within the intestinal mucosa leads to inflammation in a genetically susceptible host. Although lack of mucosal regulatory T cells causes colitis in humans and experimental rodents, patients with CD have more rather than less regulatory activity in the intestine, apparently excluding defects in tolerance as the cause of CD. Genome-wide association studies have identified many gene variants that confer susceptibility and which seem associated to diminished functioning of especially innate immunity. In apparent agreement, CD patients are impaired with respect to innate immune responses and controlling bacterial flora in the intestine. Furthermore, severe genetic deficiencies in innate immunity, like e.g., lack of NADP oxidase activity or diminished function of the Wiskott Aldrich syndrome protein are associated with colitis in mice and men, and are often mistakenly diagnosed as CD. Thus we favor the view that the primary defect in CD is a lack in innate immunity, causing second tier immunological defenses to combat otherwise easily controlled bacterial breaches of the mucosal barrier.
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http://dx.doi.org/10.4161/self.1.4.13990DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3062387PMC
April 2011

Alcohol facilitates CD1d loading, subsequent activation of NKT cells, and reduces the incidence of diabetes in NOD mice.

PLoS One 2011 Apr 1;6(4):e17931. Epub 2011 Apr 1.

Bartholin Instituttet, Rigshospitalet, Copenhagen, Denmark.

Background: Ethanol ('alcohol') is a partly hydrophobic detergent that may affect the accessibility of glycolipids thereby influencing immunological effects of these molecules.

Methods: The study included cellular in vitro tests using α-galactosylceramide (αGalCer), and in vivo NOD mice experiments detecting diabetes incidence and performing behavioural and bacterial analyses.

Results: Alcohol in concentrations from 0.6% to 2.5% increased IL-2 production from NKT cells stimulated with αGalCer by 60% (p<0.05). CD1d expressed on HeLa cells contained significantly increasing amounts of αGalCer with increasing concentrations of alcohol, suggesting that alcohol facilitated the passive loading of αGalCer to CD1d. NOD mice were found to tolerate 5% ethanol in their drinking water without signs of impairment in liver function. Giving this treatment, the diabetes incidence declined significantly. Higher numbers of CD3+CD49b+ NKT cells were found in spleen and liver of the alcohol treated compared to the control mice (p<0.05), whereas the amount of CD4+Foxp3+ regulator T cells did not differ. Increased concentrations of IFN-γ were detected in 24-hour blood samples of alcohol treated mice. Behavioural studies showed no change in attitude of the ethanol-consuming mice, and bacterial composition of caecum samples was not affected by alcohol, disqualifying these as protective mechanisms.

Conclusion: Alcohol facilitates the uptake of glycolipids and the stimulation of NKT cells, which are known to counteract Type 1 diabetes development. We propose that this is the acting mechanism by which treatment with alcohol reduces the incidence of diabetes in NOD mice. This is corroborated by epidemiology showing beneficial effect of alcohol to reduce the severity of atherosclerosis and related diseases.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0017931PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3069977PMC
April 2011

Disease-related expression of the IL6/STAT3/SOCS3 signalling pathway in ulcerative colitis and ulcerative colitis-related carcinogenesis.

Gut 2010 Feb 18;59(2):227-35. Epub 2009 Nov 18.

Department of Gastroenterology and Hepatology, Erasmus Medical Centre, Rotterdam, Netherlands.

Background: Mouse models have shown that interleukin (IL)6 stimulates survival, proliferation and progression to cancer of intestinal epithelial cells via activation of signal transducers and activators of transcription 3 (STAT3).

Objective: To investigate the expression of IL6/phosphorylated STAT3 (p-STAT3)/suppressor of cytokine signalling 3 (SOCS3) in biopsy specimens from patients with ulcerative colitis (UC) and UC-related colorectal cancer (CRC) progression.

Methods: Biopsy specimens from patients with inactive UC (n=18), active UC (n=28), UC with low-grade dysplasia (LGD) (n=9), UC with high-grade dysplasia (HGD) (n=7), UC-CRC (n=11) and sporadic CRC (n=14) were included. Biopsy specimens (n=9) from patients without colonic abnormalities served as control. The protein expression of IL6, p-STAT3 and SOCS3 was determined immunohistochemically.

Results: Patients with active UC had significantly more IL6 and p-STAT3-positive epithelial cells than both patients with inactive UC and controls (strong positive IL6: 53.6%, 11.1% and 0%, respectively; p-STAT3: 64.3%, 22.2% and 11.1%, respectively; all p
Conclusion: The importance of IL6/p-STAT3 in patients with inflammation-induced CRC was demonstrated. Moreover, SOCS3 may be involved in UC pathogenesis and the absence of SOCS3 seems critical for CRC progression.
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http://dx.doi.org/10.1136/gut.2009.184176DOI Listing
February 2010

T-cell regulation of neutrophil infiltrate at the early stages of a murine colitis model.

Inflamm Bowel Dis 2010 Mar;16(3):442-51

Department of Pediatrics, Division of Gastroenterology & Nutrition, Erasmus MC, Sophia Children's Hospital, Rotterdam, The Netherlands.

Background: T-cells are a main target for antiinflammatory drugs in inflammatory bowel disease. As the innate immune system is also implicated in the pathogenesis of these diseases, T-cell suppressors may not only inhibit T-cell-dependent production of proinflammatory mediators but also affect innate immune cell function. Specifically, these drugs may impair innate immune cell recruitment and activation through inhibition of T-cells or act independent of T-cell modulation. We explored the extent of immune modulation by the T-cell inhibitor tacrolimus in a murine colitis model.

Methods: We assessed the effects of tacrolimus on trinitro-benzene sulphonic acid (TNBS) colitis in wildtype and Rag2-deficient mice. The severity of colitis was assessed by means of histological scores and weight loss. We further characterized the inflammation using immunohistochemistry and by analysis of isolated intestinal leukocytes at various stages of disease.

Results: Tacrolimus-treated wildtype mice were less sensitive to colitis and had fewer activated T-cells. Inhibition of T-cell function was associated with strongly diminished recruitment of infiltrating neutrophils in the colon at the early stages of this model. In agreement, immunohistochemistry demonstrated that tacrolimus inhibited production of the neutrophil chemoattractants CXCL1 and CXCL2. Rag2-deficient mice displayed an enhanced baseline level of lamina propria neutrophils that was moderately increased in TNBS colitis and remained unaffected by tacrolimus.

Conclusions: Both the innate and the adaptive mucosal immune system contribute to TNBS colitis. Tacrolimus suppresses colitis directly through inhibition of T-cell activation and by suppression of T-cell-mediated recruitment of neutrophils.
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http://dx.doi.org/10.1002/ibd.21073DOI Listing
March 2010

Lung dendritic cells are stimulated by ultrafine particles and play a key role in particle adjuvant activity.

J Allergy Clin Immunol 2008 May 4;121(5):1246-54. Epub 2008 Mar 4.

Department of Immunotoxicology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.

Background: The adjuvant activity of air pollution particles on allergic airway sensitization is well known, but the cellular mechanisms underlying this adjuvant potential are not clear.

Objective: We sough to study the role of dendritic cells and the costimulatory molecules CD80 and CD86 in the adjuvant activity of ultrafine carbon black particles (CBP).

Methods: The proliferation of CFSE-labeled DO11.10 CD4 cells was studied after intranasal exposure to particles and ovalbumin (OVA). Next the frequency of myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells and their expression of CD80 and CD86 were studied in the peribronchial lymph nodes (PBLNs). The expression of costimulatory molecules was also studied on bone marrow-derived mDCs after exposure to CBPs in vitro, and the importance of costimulation in CBP adjuvant activity was assessed by using CD80/CD86-deficient mice or cytotoxic T lymphocyte-associated antigen 4 (CTLA4)-Ig in vivo.

Results: Our data show that CBPs plus OVA caused proliferation of DO11.10 CD4 cells and high levels of cytokine production in the PBLNs. Furthermore, the combined CBP plus OVA exposure increased the number of mDCs and expression of costimulatory molecules in the PBLNs. In addition, CBPs upregulated the expression of CD80/CD86 molecules on dendritic cells in vitro, which are necessary for the particle adjuvant effects in vivo.

Conclusion: Together this study shows the importance of dendritic cells and costimulation in particle adjuvant activity. Furthermore, we show for the first time that CBPs can also directly induce maturation of dendritic cells.
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http://dx.doi.org/10.1016/j.jaci.2008.01.010DOI Listing
May 2008

Ultrafine carbon black particles cause early airway inflammation and have adjuvant activity in a mouse allergic airway disease model.

Toxicol Sci 2005 Oct 13;87(2):409-18. Epub 2005 Jul 13.

Department of Immunotoxicology, Institute for Risk Assessment Sciences, Utrecht University, The Netherlands.

To gain more insight into the mechanisms of particulate matter (PM)-induced adjuvant activity, we studied the kinetics of airway toxicity/inflammation and allergic sensitization to ovalbumin (OVA) in response to ultrafine carbon black particles (CBP). Mice were exposed intranasally to OVA alone or in combination with different concentrations of CBP. Airway toxicity and inflammation were assessed at days 4 and 8. Immune adjuvant effects were studied in the lung draining peribronchial lymph nodes (PBLN) at day 8. Antigen-specific IgE was measured at days 21 and 28, whereas allergic airway inflammation was studied after OVA challenges (day 28). Results show that a total dose of 200 microg CBP per mouse, but not 20 microg or 2 microg, induced immediate airway inflammation. This 200 microg CBP was the only dose that had immune adjuvant activity, by inducing enlargement of the PBLN and increasing OVA-specific production of Th2 cytokines (IL-4, IL-5, and IL-10). The immune adjuvant activity of 200 microg CBP dosing was further examined. Whereas increased OVA-specific IgE levels in serum on day 21 confirms systemic sensitization, this was further supported by allergic airway inflammation after challenges with OVA. Our data show a link between early airway toxicity and adjuvant effects of CBP. In addition, results indicate that local cytokine production early after exposure to CBP is predictive of allergic airway inflammation. In addition this model appears suitable for studying the role of airway toxicity, inflammation and other mechanisms of particle adjuvant activity, and predicting the adjuvant potential of different particles.
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http://dx.doi.org/10.1093/toxsci/kfi255DOI Listing
October 2005