Peggy Bodammer

NOD2 Stimulation by Staphylococcus aureus-Derived Peptidoglycan Is Boosted by Toll-Like Receptor 2 Costimulation with Lipoproteins in Dendritic Cells

ABSTRACT Mutations in the nucleotide-binding oligomerization domain-containing protein 2 (NOD2) play an important role in the pathogenesis of Crohns disease. NOD2 is an intracellular pattern recognition receptor (PRR) that senses bacterial peptidoglycan (PGN) structures, e.g., muramyl dipeptide (MDP). Here we focused on the effect of more-cross-linked, polymeric PGN fragments (PGNpol) in the activation of the innate immune system. In this study, the effect of combined NOD2 and Toll-like receptor 2 (TLR2) stimulation was examined compared to single stimulation of the NOD2 receptor alone. PGNpol species derived from a lipoprotein-containing Staphylococcus aureus strain (SA113) and a lipoprotein-deficient strain (SA113 Δlgt) were isolated. While PGNpol constitutes a combined NOD2 and TLR2 ligand, lipoprotein-deficient PGNpolΔlgt leads to activation of the immune system only via the NOD2 receptor. Murine bone marrow-derived dendritic cells (BMDCs), J774 cells, and Mono Mac 6 (MM6) cells were stimulated with these ligands. Cytokines (interleukin-6 [IL-6], IL-12p40, and tumor necrosis factor alpha [TNF-α]) as well as DC activation and maturation parameters were measured. Stimulation with PGNpolΔlgt did not lead to enhanced cytokine secretion or DC activation and maturation. However, stimulation with PGNpol led to strong cytokine secretion and subsequent DC maturation. These results were confirmed in MM6 and J774 cells. We showed that the NOD2-mediated activation of DCs with PGNpol was dependent on TLR2 costimulation. Therefore, signaling via both receptors leads to a more potent activation of the immune system than that with stimulation via each receptor alone.

S100 Proteins as Diagnostic and Prognostic Markers in Colorectal and Hepatocellular Carcinoma

Context Clinical and experimental studies have suggested a link between S100 gene expression and neoplastic disorders, however, the molecular mechanisms of this association are not well understood. The aim of this review was to conduct a comprehensive literature search in order to understand the possible underlying molecular mechanisms of this association. We also discuss their application as diagnostic and prognostic markers in colorectal and hepatocellular carcinoma. Evidence Acquisitions We searched Pubmed (NLM) and Web of Science (ISI Web of Knowledge). Results S100 genes display a complex expression pattern in colorectal and hepatocel lular carcinoma. They are expressed in tumor and/or tumor stroma cells, and they exert both pro- and antitumorigenic actions. In view of this complexity, it becomes clear that S100 proteins might act as both friend and foe. The biological role of the S100 genes is predicted to depend on the relative contributions of the different cell types at specific stages of tumor progression. Conclusions Further research is required in order to uncover the functional role of S100 genes in tumorigenesis. Answers to this issue are needed before we can more fully understand the clinical relevance of S100 protein expression within epithelial tumors, with regard to their potential applicability as biomarkers for diagnosis and therapy decisions.

Prophylactic Application of Bovine Colostrum Ameliorates Murine Colitis via Induction of Immunoregulatory Cells

Epidemiologic studies suggest a relationship between early weaning and the incidence of inflammatory bowel disease. Herein, we addressed the question whether bovine colostrum, the first milk produced by mammals, is able to prevent dextran sulfate sodium (DSS)-induced colitis in mice. Prior to induction of colitis with 5% DSS, Naval Medical Research Institute mice were fed bovine colostrum [BV-20 or 200 mg/kg body weight (BW)], BSA (20 mg/kg BW), or water (100 μL) daily by oral gavage for 2 wk. The clinical severity of colitis was determined by scoring changes in BW and colon length reduction. Following 2 wk of observation, the colons were removed for histologic and immunohistochemical evaluation of inflammation. Flow cytometric phenotyping of leukocyte subsets was performed from peripheral blood, mesenteric lymph nodes, and spleens. Administration of bovine colostrum improved the clinical and histologic severity of colorectal inflammation. Compared with BSA-fed and water-fed controls, BV-20 pretreated mice had significantly less severe weight loss and decreased colon shortening. Beneficial effects were accompanied by redistribution of immunoregulatory, peripheral and splenic γδ TCR(+) cells, and CD11b(+)Gr1(+) cells. Higher colostrum doses did not affect disease activity. In summary, prophylactic administration of colostrum improved clinical symptoms of colorectal inflammation in a well-established mouse model of DSS-induced colitis. Further investigations will target the underlying immunomodulatory mechanisms to our approach.

Mucosa‐attached bacterial community in Crohn's disease coheres with the clinical disease activity index

In inflammatory bowel diseases (IBD), microbial communities often become imbalanced suggesting abnormal microbial-gut interactions. In this study, we analysed the mucosa-attached gut microbiota from 26 Crohns disease (CD) patients using 16S rRNA gene amplicon sequencing. The samples were stratified according to their disease activity (Crohns disease activity index, CDAI). The different disease activity categories had a comparable bacterial richness. Bacterial communities of patients in remission and intermediate CDAI (0-220) were relatively similar and dominated by the genus Bacteroides (>40%). The bacterial composition of patients assigned to a high CDAI category was dominated by Pelomonas (25%) and Flavobacterium (13%) but had a low relative abundance of Bacteroidetes (4%). This indicates the presence of specific abundant bacterial taxa at different CDAI levels. In addition, bacterial communities were also significantly influenced when a tumour necrosis factor (TNF)-α inhibitor was applied or by the local mucosal inflammation level. As a consequence, a shift of the microbial composition may also indicate a change of the disease activity in CD patients.

Alterations in the mucosa-associated bacterial composition in Crohn’s disease: a pilot study

IntroductionChanges in the intestinal bacterial composition seem to play a major role in the pathogenesis and in the clinical course of inflammatory bowel diseases (IBD), which consist of Crohn’s disease (CD), and ulcerative colitis (UC). Mutations in the NOD2 gene are the most important genetic risk factors for the development of CD. In this study, the association between mucosal biopsies and the mucosa-associated bacterial composition from CD and UC patients regarding their genetic risk factors (mutations in the NOD2 gene), their endoscopic activity, and their medical therapy (TNF-α blocking therapy) was examined.Material and methodsSeventy biopsies from routine colonoscopies from 33 IBD patients (26 CD and 7 UC) were obtained. Disease activity and clinical characteristics were assessed. Seven different bacterial strains (Bacteroides fragilis, Escherichia coli, Prevotella melaninogenica, Clostridium coccoides, Clostridium difficile, Bifidobacterium bifidum, and Faecalibacterium prausnitzii) were quantified using real-time PCR. NOD2 genotyping from patients with CD was performed.ResultsFive of the 24 patients were positive for at least one mutation in the NOD2 gene. The bacterial composition was different in CD compared to UC, in macroscopic healthy compared to macroscopic inflamed biopsies, in NOD2 mutated compared to NOD2 wildtype patients, and in patients receiving TNF-α blocking therapy compared to patients without this treatment.ConclusionThis study further characterizes the mucosa-associated bacteria in IBD patients. Different clinical situations lead to an altered mucosa-associated bacterial composition. The analyzed bacteria could be promising targets for cost-effective surveillance or therapies in IBD patients.

First Human Application of a Novel Adsorptive‐Type Cytapheresis Module in Patients With Active Ulcerative Colitis: A Pilot Study

The aim of this study was to evaluate the safety, tolerability, technical performance and clinical efficacy of a novel adsorptive‐type cytapheresis module in patients with active ulcerative colitis. Ten patients with ulcerative colitis (clinical activity index 6–10) were recruited. The new adsorber (Nikkiso, Tokyo, Japan) was specifically designed to remove platelets, granulocytes and monocytes from peripheral blood using an extracorporeal circulation. Cytapheresis treatments were performed weekly for five consecutive weeks (each with a 60‐min duration). Safety and tolerability were evaluated by investigating vital parameters, routine laboratory tests, adverse event reporting and a questionnaire. Disease activity was evaluated by assessing the clinical activity index as well as the endoscopic index, according to Rachmilewitz. Technical performance and biocompatibility were investigated by repeated measurements of cellular blood count, complement factor C3a and cell surface markers before, during and after the apheresis treatments. The cytapheresis treatments were “well” to “very well” tolerated by the patients. All measured safety parameters remained essentially unchanged. Performance data showed that platelets, monocytes and neutrophil granulocytes were effectively reduced during the cytapheresis treatments. Apheresis treatment was associated with high remission rates (80% at week 10). Clinical remission was accompanied by the reduction of the endoscopic index in four out of the nine eligible patients. Levels of C3a did not significantly increase during cytapheresis treatments. The novel device has been shown to be safe, well tolerated and clinically efficient. It offered a very good biocompatibility and platelet elimination capacity.

The PDZ-interaction of the intestinal anion exchanger downregulated in adenoma (DRA; SLC26A3) facilitates its movement into Rab11a-positive recycling endosomes

Electroneutral NaCl absorption in the ileum and colon is mediated by downregulated in adenoma (DRA) (Cl⁻/HCO₃⁻ exchanger; SLC26A3) and Na⁺/H⁺ exchanger 3 (NHE3, SLC9A3). Surface expression of transport proteins undergoes basal and regulated recycling by endo- and exocytosis. Expression and activity of DRA in the plasma membrane depend on intact lipid rafts, phosphatidylinositol 3-kinase (PI3-kinase), and the PDZ interaction of DRA. However, it is unknown how the PDZ interaction of DRA affects its trafficking to the cell surface. Therefore, the (re)cycling pathway of DRA was investigated in HEK cells stably expressing enhanced green fluorescent protein (EGFP)-DRA or EGFP-DRA-ETKFminus (a mutant lacking the PDZ interaction motif). Early, late, and recycling endosomes were immunoisolated by precipitating stably transfected mCherry-hemagglutinin (HA)-Rab5a, -7a, or -11a. EGFP-DRA and EGFP-DRA-ETKFminus were equally present in early endosomes. In recycling endosomes, wild-type DRA was preferentially present, whereas, in late endosomes, DRA-ETKF-minus dominated. Correspondingly, EGFP-DRA colocalized with mCherry-HA-Rab11a in recycling endosomes, whereas EGFP-DRA-ETKFminus colocalized with mCherry-HA-Rab7a in late endosomes. Functionally, this different distribution was reflected by a shorter half-life of the mutant DRA. Transient expression of dominant-negative Rab11a(S25N) inhibited the activity (-17%, P < 0.05) and the cell surface expression of DRA (-30%, P < 0.05). Transient transfection of Rab4a or its dominant-negative mutant Rab4a(S22N) was without effect and thus excluded participation of the rapid recycling pathway. Taken together, the PDZ interaction of DRA facilitates its movement into Rab11a-positive recycling endosomes, from where it is inserted in the plasma membrane. A scenario emerges where specific PDZ adaptor proteins are present along several compartments of the endocytosis-recycling pathway.

Bacterial Immunotherapy-Antitumoral Potential of the Streptococcal Toxin Streptolysin S-

Chronic infections can lead to cancer. However, acute infection has beneficial effects often contributing to complete eradication of tumors. In the wake of this, bacteria and their related products were applied therapeutically for experimental immunotherapy. They exhibit direct antitumoral potential and are recognized by the host’s immune system via Toll-like receptors (TLRs) finally promoting pro-inflammatory, often Th1-directed immune responses.

Nutritional strategies to enhance adaptation in intestinal failure.

Purpose of reviewThis article summarizes the current and potential future nutritional approaches to stimulate adaptation in intestinal failure. Adaptation in this context usually refers to intestinal adaptation but also involves changes in whole body physiology as well as in eating/drinking behavior. Recent findingsAdaptation largely depends on residual functional anatomy. Luminal exposure to complex nutrients is the most important trigger for intestinal adaptation. Enteral fat as well as enteral or parenteral short chain fatty acids have a specific stimulatory effect. Zinc and vitamin A status need to be optimized for adaptation to proceed and be maintained. In the context of maintaining sodium and water homeostasis, flushing the remnant intestine because of uncontrolled thirst/drinking must be avoided. Complications of nutritional care such as malnutrition, intestinal failure-associated liver disease, and recurrent line sepsis also need optimal management. SummaryStimulation by luminal nutrients as well as prophylaxis against and treatment of (nutritional) complications are the cornerstones of adaptation to the short bowel situation. Based on ample data from animal studies but only limited evidence in humans specific nutritional stimulators need to be studied more rigorously. As long as such data are missing they can be tried on an individual basis.