Publications by authors named "Benno Weigmann"

59 Publications

A Group of Cationic Amphiphilic Drugs Activates MRGPRX2 and Induces Scratching Behavior in Mice.

J Allergy Clin Immunol 2021 Feb 19. Epub 2021 Feb 19.

Department of Medicine 1, Friedrich-Alexander-University Erlangen-Nürnberg, Germany. Electronic address:

Background: Mas gene-related G protein-coupled receptors (MRGPRs) are a GPCR family responsive to various exogenous and endogenous agonists, playing a fundamental role in pain and itch sensation. The primate-specific family member MRGPRX2 and its murine orthologue MRGPRB2 are expressed by mast cells, mediating IgE-independent signaling and pseudo-allergic drug reactions.

Objectives: Therefore, knowledge about the function and regulation of MRGPRX2/MRGPRB2 is of major importance in prevention of drug hypersensitivity reactions and drug-induced pruritus.

Methods: To identify novel MRGPR (ant)agonists, we screened a library of pharmacologically active compounds utilizing a high-throughput calcium mobilization assay. Identified hit compounds were analyzed for their pseudo-allergic and pruritogenic effects in mice and human.

Results: We found a class of commonly used drugs activating MRGPRX2 which consists to a large extent of antidepressants, antiallergic drugs, and antipsychotics. Three-dimensional pharmacophore modeling revealed structural similarities of the identified agonists, classifying them as cationic amphiphilic drugs. Mast cell activation was investigated using the three representatively selected antidepressants clomipramine, paroxetine, and desipramine. Indeed, we could show a concentration-dependent activation and MRGPRX2-dependent degranulation of the human mast cell line LAD2. Furthermore, clomipramine, paroxetine, and desipramine were able to induce degranulation of human skin and murine peritoneal mast cells. These substances elicited dose-dependent scratching behavior upon intradermal injection in C57BL/6 mice but less in MRGPRB2-mutant mice as well as wheal-and-flare reactions upon intradermal injections in humans.

Conclusion: Our results contribute to the characterization of structure-activity relationships and functionality of MRGPRX2 ligands and facilitate prediction of adverse reactions like drug-induced pruritus to prevent severe drug hypersensitivity reactions.
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http://dx.doi.org/10.1016/j.jaci.2020.12.655DOI Listing
February 2021

Role of the IL-2 inducible tyrosine kinase ITK and its inhibitors in disease pathogenesis.

J Mol Med (Berl) 2020 10 18;98(10):1385-1395. Epub 2020 Aug 18.

Department of Medicine 1, Kussmaul Campus for Medical Research, University of Erlangen-Nürnberg, Hartmannstr.14, 91052, Erlangen, Germany.

ITK (IL-2-inducible tyrosine kinase) belongs to the Tec family kinases and is mainly expressed in T cells. It is involved in TCR signalling events driving processes like T cell development as well as Th2, Th9 and Th17 responses thereby controlling the expression of pro-inflammatory cytokines. Studies have shown that ITK is involved in the pathogenesis of autoimmune diseases as well as in carcinogenesis. The loss of ITK or its activity either by mutation or by the use of inhibitors led to a beneficial outcome in experimental models of asthma, inflammatory bowel disease and multiple sclerosis among others. In humans, biallelic mutations in the ITK gene locus result in a monogenetic disorder leading to T cell dysfunction; in consequence, mainly EBV infections can lead to severe immune dysregulation evident by lymphoproliferation, lymphoma and hemophagocytic lymphohistiocytosis. Furthermore, patients who suffer from angioimmunoblastic T cell lymphoma have been found to express significantly more ITK. These findings put ITK in the strong focus as a target for drug development.
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http://dx.doi.org/10.1007/s00109-020-01958-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7524833PMC
October 2020

The JAK1/3 inhibitor tofacitinib suppresses T cell homing and activation in chronic intestinal inflammation.

J Crohns Colitis 2020 Aug 18. Epub 2020 Aug 18.

Department of Medicine, University Clinic of Erlangen-Nuremberg, Kussmaul Campus for Medical Research, Erlangen, Germany.

Background & Aims: The molecular mechanism of action of the Janus kinase (JAK) inhibitor tofacitinib is poorly understood.

Methods: Here, we analysed the inhibitory effect of tofacitinib on mucosal and blood T cells from patients with ulcerative colitis (UC). Furthermore tofacitinib treatment was analysed in experimental colitis models and wound healing. Additionally, tofacitinib effects were analysed in bioassays.

Results: Tofacitinib significantly reduced T cell derived inflammatory cytokine production (Th2, Th9, Th17) in patients with active UC. Additionally, impaired expression of the homing receptors alpha4/beta1 and alpha4/beta7 as well as reduced gut homing capacity of T cells in a humanized mouse model of colitis were observed. Tofacitinib suppressed acute and chronic oxazolone colitis compared to untreated wild-type mice associated with downregulation of cytokines produced by Th2, Th9 and Th17 cells. Functionally, tofacitinib induced apoptosis of intestinal epithelial cells and prevented mucosal wound healing in vivo at higher concentration. Thus, our findings suggest that tofacitinib is quite effective in protecting from colitis by inhibition of a bundle of T cell derived cytokines like IL-5, IL-6, IL-9, IL-13 and IL-17A.

Conclusion: Application of tofacitinib emerges as an attractive concept for treatment of chronic intestinal inflammation at lower concentrations, whereas higher concentrations require attention due to prolonged wound healing.
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http://dx.doi.org/10.1093/ecco-jcc/jjaa162DOI Listing
August 2020

Microenvironmental Th9 and Th17 lymphocytes induce metastatic spreading in lung cancer.

J Clin Invest 2020 07;130(7):3560-3575

Max Planck Institute for Heart and Lung Research, Department of Lung Development and Remodeling, member of the German Center for Lung Research (DZL), member of Cardio-Pulmonary Institute (CPI), Bad Nauheim, Germany.

Immune microenvironment plays a critical role in lung cancer control versus progression and metastasis. In this investigation, we explored the effect of tumor-infiltrating lymphocyte subpopulations on lung cancer biology by studying in vitro cocultures, in vivo mouse models, and human lung cancer tissue. Lymphocyte conditioned media (CM) induced epithelial-mesenchymal transition (EMT) and migration in both primary human lung cancer cells and cell lines. Correspondingly, major accumulation of Th9 and Th17 cells was detected in human lung cancer tissue and correlated with poor survival. Coculturing lung cancer cells with Th9/Th17 cells or exposing them to the respective CM induced EMT in cancer cells and modulated the expression profile of genes implicated in EMT and metastasis. These features were reproduced by the signatory cytokines IL-9 and IL-17, with gene regulatory profiles evoked by these cytokines partly overlapping and partly complementary. Coinjection of Th9/Th17 cells with tumor cells in WT, Rag1-/-, Il9r-/-, and Il17ra-/- mice altered tumor growth and metastasis. Accordingly, inhibition of IL-9 or IL-17 cytokines by neutralizing antibodies decreased EMT and slowed lung cancer progression and metastasis. In conclusion, Th9 and Th17 lymphocytes induce lung cancer cell EMT, thereby promoting migration and metastatic spreading and offering potentially novel therapeutic strategies.
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http://dx.doi.org/10.1172/JCI124037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7324180PMC
July 2020

miRNA142-3p targets Tet2 and impairs Treg differentiation and stability in models of type 1 diabetes.

Nat Commun 2019 12 13;10(1):5697. Epub 2019 Dec 13.

Institute of Diabetes Research, Group Immune Tolerance in Type 1 Diabetes, Helmholtz Diabetes Center at Helmholtz Zentrum München, 80939, Munich, Germany.

In type 1 diabetes, the appearance of islet autoantibodies indicates the onset of islet autoimmunity, often many years before clinical symptoms arise. While T cells play a major role in the destruction of pancreatic beta cells, molecular underpinnings promoting aberrant T cell activation remain poorly understood. Here, we show that during islet autoimmunity an miR142-3p/Tet2/Foxp3 axis interferes with the efficient induction of regulatory T (Treg) cells, resulting in impaired Treg stability in mouse and human. Specifically, we demonstrate that miR142-3p is induced in islet autoimmunity and that its inhibition enhances Treg induction and stability, leading to reduced islet autoimmunity in non-obese diabetic mice. Using various cellular and molecular approaches we identify Tet2 as a direct target of miR142-3p, thereby linking high miR142-3p levels to epigenetic remodeling in Tregs. These findings offer a mechanistic model where during islet autoimmunity miR142-3p/Tet2-mediated Treg instability contributes to autoimmune activation and progression.
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http://dx.doi.org/10.1038/s41467-019-13587-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6910913PMC
December 2019

Short-term cold exposure supports human Treg induction in vivo.

Mol Metab 2019 10 5;28:73-82. Epub 2019 Aug 5.

Institute for Diabetes Research, Group Immune Tolerance in Diabetes, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health, Munich-Neuherberg, Germany; German Center for Diabetes Research (DZD), Munich, Germany; Division of Clinical Pharmacology, Department of Medicine IV, Ludwig-Maximilians-Universität München, Munich, Germany. Electronic address:

Objective: Obesity and type-2 diabetes (T2D) are metabolic diseases that represent a critical health problem worldwide. Metabolic disease is differentially associated with fat distribution, while visceral white adipose tissue (VAT) is particularly prone to obesity-associated inflammation. Next to their canonical function of immune suppression, regulatory T cells (Tregs) are key in controlling adipose tissue homeostasis. Towards understanding the molecular underpinnings of metabolic disease, we focus on how environmental-metabolic stimuli impinge on the functional interplay between Tregs and adipose tissue. Here, cold exposure or beta3-adrenergic signaling are a promising tool to increase energy expenditure by activating brown adipose tissue, as well as by reducing local inflammation within fat depots by supporting immunosuppressive Tregs. However, in humans, the underlying mechanisms that enable the environmental-immune crosstalk in the periphery and in the respective tissue remain currently unknown.

Methods: We used combinatorial approaches of next generation humanized mouse models and in vitro and in vivo experiments together with beta3-adrenergic stimulation to dissect the underlying mechanisms of human Treg induction exposed to environmental stimuli such as cold. To test the translational relevance of our findings, we analyzed samples from the FREECE study in which human subjects were exposed to individualized cooling protocols. Samples were analyzed ex vivo and after in vitro Treg induction using qRT-PCR, immunofluorescence, as well as with multicolor flow cytometry and cell sorting.

Results: In vivo application of the beta3-adrenergic receptor agonist mirabegron in humanized mice induced thermogenesis and improved the Treg induction capacity of naïve T cells isolated from these animals. Using samples from the human FREECE study, we demonstrate that a short-term cold stimulus supports human Treg induction in vitro and in vivo. Mechanistically, we identify BORCS6 encoding the Ragulator-interacting protein C17orf59 to be significantly induced in human CD4 T cells upon short-term cold exposure. Strong mTOR signaling is known to limit successful Treg induction and thus likely by interfering with mTOR activation at lysosomal surfaces, C17orf59 improves the Treg induction capacity of human naïve T cells upon cold exposure.

Conclusions: These novel insights into the molecular underpinnings of human Treg induction suggest an important role of Tregs in linking environmental stimuli with adipose tissue function and metabolic diseases. Moreover, these discoveries shed new light on potential approaches towards tailored anti-inflammatory concepts that support human adipose tissue homeostasis by enabling Tregs.
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http://dx.doi.org/10.1016/j.molmet.2019.08.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6822223PMC
October 2019

NLRP6 Deficiency in CD4 T Cells Decreases T Cell Survival Associated with Increased Cell Death.

J Immunol 2019 07 31;203(2):544-556. Epub 2019 May 31.

Department of Biomedicine, University of Basel, CH-4031 Basel, Switzerland;

The nucleotide-binding oligomerization domain (NOD)-like receptors belong to the family of pattern recognition receptors (PRRs). NOD-like receptors play a role in regulation of innate immune response by recognition of both pathogen-associated molecular patterns that are engulfed during phagocytic process and danger-associated molecular patterns that are mainly byproducts of cell stress mediated response. NOD-like family pyrin domain containing 6 (NLRP6) is one of the 14 pyrin domain-containing receptors. NLRP6 is highly expressed by epithelial and goblet cells to regulate epithelial renewal and mucus production in mice and humans, but its function in T cells is rather unknown. Increased caspase-1 activation and cell death were observed in mouse -deficient T cells following adoptive transfer into -deficient mice, indicating that deficiency in CD4 T cells led to decreased survival.
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http://dx.doi.org/10.4049/jimmunol.1800938DOI Listing
July 2019

Advances in orally-delivered pH-sensitive nanocarrier systems; an optimistic approach for the treatment of inflammatory bowel disease.

Int J Pharm 2019 Mar 4;558:201-214. Epub 2019 Jan 4.

Medical Clinic I, University Hospital Erlangen, Research Campus, 91052 Erlangen, Germany.

Inflammatory bowel disease (IBD) is the inflammation of the gastrointestinal tract (GIT) affecting the colon and ileum in particular. Increasing IBD prevalence worldwide is alarming, and needs to be resolved. Due to the limited therapeutic efficacy, accompanying adverse effects, dependence, and pharmacokinetics issues of the available therapy, IBD patients have compromised quality of life. Meanwhile, conventional drug delivery systems (DDS) for IBD face many obstacles en-route to the colon, such as physiological and pathophysiological barriers, genetic variability, disease severity, and nutrition status. Therefore, the pH-dependent nanocarrier DDS is a recent advancement that fulfills the need for a more tolerable and effective remedy for IBD. It facilitates localized and targeted action, eliminating systemic adverse effects and unnecessary flushing of the drug from the inflamed colon tissues. The integration of a pH-sensitive polymer as a nanocarrier provides protection in drug transport to the lower region of the GIT. In this review, we will briefly explain IBD pathophysiology, the pros and cons of pH-dependent conventional DDS, and highlight a novel pH-dependent nanocarrier system for treating the disease.
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http://dx.doi.org/10.1016/j.ijpharm.2018.12.074DOI Listing
March 2019

Tumor immunoevasion via acidosis-dependent induction of regulatory tumor-associated macrophages.

Nat Immunol 2018 12 5;19(12):1319-1329. Epub 2018 Nov 5.

Institute for Immunology, University Medical Center, Johannes Gutenberg University Mainz, Mainz, Germany.

Many tumors evolve sophisticated strategies to evade the immune system, and these represent major obstacles for efficient antitumor immune responses. Here we explored a molecular mechanism of metabolic communication deployed by highly glycolytic tumors for immunoevasion. In contrast to colon adenocarcinomas, melanomas showed comparatively high glycolytic activity, which resulted in high acidification of the tumor microenvironment. This tumor acidosis induced Gprotein-coupled receptor-dependent expression of the transcriptional repressor ICER in tumor-associated macrophages that led to their functional polarization toward a non-inflammatory phenotype and promoted tumor growth. Collectively, our findings identify a molecular mechanism of metabolic communication between non-lymphoid tissue and the immune system that was exploited by high-glycolytic-rate tumors for evasion of the immune system.
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http://dx.doi.org/10.1038/s41590-018-0226-8DOI Listing
December 2018

Alternative Splice Forms of CYLD Mediate Ubiquitination of SMAD7 to Prevent TGFB Signaling and Promote Colitis.

Gastroenterology 2019 02 10;156(3):692-707.e7. Epub 2018 Oct 10.

Institute for Molecular Medicine, University Medical Centre, Johannes Gutenberg University of Mainz, Mainz, Germany. Electronic address:

Background & Aims: The CYLD lysine 63 deubiquitinase gene (CYLD) encodes tumor suppressor protein that is mutated in familial cylindromatosus, and variants have been associated with Crohn disease (CD). Splice forms of CYLD that lack exons 7 and 8 regulate transcription factors and functions of immune cells. We examined the expression of splice forms of CYLD in colon tissues from patients with CD and their effects in mice.

Methods: We performed immunohistochemical analyses of colon tissues from patients with untreated CD and patients without inflammatory bowel diseases (controls). We obtained mice that expressed splice forms of CYLD (sCYLD mice) without or with SMAD7 (sCYLD/SMAD7 mice) from transgenes and CYLD-knockout mice (with or without transgenic expression of SMAD7) and performed endoscopic analyses. Colitis was induced in Rag1 mice by transfer of CD4 CD62L T cells from C57/Bl6 or transgenic mice. T cells were isolated from mice and analyzed by flow cytometry and quantitative real-time polymerase chain reaction and intestinal tissues were analyzed by histology and immunohistochemistry. CYLD forms were expressed in mouse embryonic fibroblasts, primary T cells, and HEK293T cells, which were analyzed by immunoblot, mobility shift, and immunoprecipitation assays.

Results: The colonic lamina propria from patients with CD was infiltrated by T cells and had higher levels of sCYLD (but not full-length CYLD) and SMAD7 than tissues from controls. Incubation of mouse embryonic fibroblasts and T cells with transforming growth factor β increased their production of sCYLD and decreased full-length CYLD. Transgenic expression of sCYLD and SMAD7 in T cells prevented the differentiation of regulatory T cells and T-helper type 17 cells and increased the differentiation of T-helper type 1 cells. The same effects were observed in colon tissues from sCYLD/SMAD7 mice but not in those from CYLD-knockout SMAD7 mice. The sCYLD mice had significant increases in the numbers of T-helper type 1 cells and CD44 CD62L memory-effector CD4 T cells in the spleen and mesenteric lymph nodes compared with wild-type mice; sCYLD/SMAD7 mice had even larger increases. The sCYLD/SMAD7 mice spontaneously developed severe colitis, with infiltration of the colon by dendritic cells, neutrophils, macrophages, and CD4 T cells and increased levels of Ifng, Il6, Il12a, Il23a, and Tnf mRNAs. Co-transfer of regulatory T cells from wild-type, but not from sCYLD/SMAD7, mice prevented the induction of colitis in Rag1 mice by CD4 T cells. We found increased levels of poly-ubiquitinated SMAD7 in sCYLD CD4 T cells. CYLD formed a nuclear complex with SMAD3, whereas sCYLD recruited SMAD7 to the nucleus, which inhibited the expression of genes regulated by SMAD3 and SMAD4. We found that sCYLD mediated lysine 63-linked ubiquitination of SMAD7. The sCYLD-SMAD7 complex inhibited transforming growth factor β signaling in CD4 T cells.

Conclusions: Levels of the spliced form of CYLD are increased in colon tissues from patients with CD. sCYLD mediates ubiquitination and nuclear translocation of SMAD7 and thereby decreases transforming growth factor β signaling in T cells. This prevents immune regulatory mechanisms and leads to colitis in mice.
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http://dx.doi.org/10.1053/j.gastro.2018.10.023DOI Listing
February 2019

Wheat amylase-trypsin inhibitors exacerbate intestinal and airway allergic immune responses in humanized mice.

J Allergy Clin Immunol 2019 01 21;143(1):201-212.e4. Epub 2018 Mar 21.

Department of Dermatology, University Medical Center, Johannes Gutenberg University, Mainz, Germany; Research Center for Immunotherapy, University Medical Center, Johannes Gutenberg University, Mainz, Germany.

Background: Amylase-trypsin inhibitors (ATIs) in wheat and related cereals are potent activators of myeloid innate immune cells via engagement of TLR4. Furthermore, ATIs have been shown to serve as adjuvants in experimental intestinal inflammatory diseases.

Objective: The aim of this study was to analyze whether ATIs are also modifiers of allergic inflammation.

Methods: Therefore, CD4 T cells from donors sensitized to grass or birch pollen were stimulated with autologous allergen-pulsed dendritic cells in the presence or absence of ATIs or the control storage protein zein from corn. To analyze allergen-induced gut and lung inflammation, immunodeficient mice were engrafted with PBMCs from these allergic donors plus the respective allergen, and fed with selected diets. Three weeks later, inflammation was induced by rectal or intranasal allergen challenge and monitored by mini endoscopy or airway hyperreactivity, respectively.

Results: Allergen-specific T-cell proliferation and cytokine production was significantly exacerbated by ATIs and not by zein. In vivo, allergen-specific human IgE level was strongly elevated in sera of mice receiving an ATI-containing diet compared with mice that were fed gluten-free and thus ATI-free diet. Importantly, allergen-induced IgE-dependent colitis and airway hyperreactivity were also enhanced in ATI-fed mice. Gut inflammation was further increased in mice receiving an additional ATI injection and even detectable in the absence of the aeroallergen, whereas zein had no such effect. Injection of anti-human TLR4 mAbs or the anti-human IgE mAb omalizumab completely abolished ATI-induced allergic inflammation.

Conclusions: These results underline that wheat ATIs are important nutritional activators and adjuvants of allergy, which might be exploited for nutritional therapeutic strategies.
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http://dx.doi.org/10.1016/j.jaci.2018.02.041DOI Listing
January 2019

Regulation of the intestinal immune system by flavonoids and its utility in chronic inflammatory bowel disease.

World J Gastroenterol 2018 Feb;24(8):877-881

Department of Medicine 1, University Medical Center, Erlangen 91052, Germany.

Flavonoids are phytochemicals which can regulate the activity of the intestinal immune system. In patients with chronic inflammatory bowel disease (IBD) there is an overexpression and imbalance of the components of the inflammatory immune reactions which are chronically activated. Suppression of inflammation can be achieved by anti-inflammatory drugs which are used in clinical medicine but these can cause serious side effects. Flavonoids can have natural immunosuppressive properties and inhibit the activation of immune cells and its effectors (chemokines, TNF-, cytokines). Phytochemicals such as flavonoids bind to the nuclear Ah (aryl hydrocarbon) -receptor thereby stimulating protective enzyme activities. As shown by clinical evidence in patients and by experimental work some flavonoids (apigenin, epigallocatechin gallate) were effective in the inhibition of inflammation. Instead of or additionally to anti-inflammatory drugs flavonoids can be used in IBD patients to treat the over-reactive immunologic system. This is accomplished by upregulation of the Ah-receptor. Flavonoids interact with toll-like receptors expressing on the surface of immune cells, then they were internalized to the cytosol and transferred into the nucleus, where they were attached to the Ah-receptor. The Ah-receptor binds to the Ah-R nuclear translocator and Ah response element beneficial protective enzymes and cytokines are induced, leading to upregulation of the anti-inflammatory system.
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http://dx.doi.org/10.3748/wjg.v24.i8.877DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5829151PMC
February 2018

A miRNA181a/NFAT5 axis links impaired T cell tolerance induction with autoimmune type 1 diabetes.

Sci Transl Med 2018 01;10(422)

Group Immune Tolerance in Type 1 Diabetes, Institute for Diabetes Research, Helmholtz Diabetes Center at Helmholtz Zentrum München, Munich, Germany.

Molecular checkpoints that trigger the onset of islet autoimmunity or progression to human type 1 diabetes (T1D) are incompletely understood. Using T cells from children at an early stage of islet autoimmunity without clinical T1D, we find that a microRNA181a (miRNA181a)-mediated increase in signal strength of stimulation and costimulation links nuclear factor of activated T cells 5 (NFAT5) with impaired tolerance induction and autoimmune activation. We show that enhancing miRNA181a activity increases NFAT5 expression while inhibiting FOXP3 regulatory T cell (T) induction in vitro. Accordingly, T induction is improved using T cells from NFAT5 knockout (NFAT5ko) animals, whereas altering miRNA181a activity does not affect T induction in NFAT5ko T cells. Moreover, high costimulatory signals result in phosphoinositide 3-kinase (PI3K)-mediated NFAT5, which interferes with FoxP3 T induction. Blocking miRNA181a or NFAT5 increases T induction in murine and humanized models and reduces murine islet autoimmunity in vivo. These findings suggest targeting miRNA181a and/or NFAT5 signaling for the development of innovative personalized medicines to limit islet autoimmunity.
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http://dx.doi.org/10.1126/scitranslmed.aag1782DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828501PMC
January 2018

A Stat6/Pten Axis Links Regulatory T Cells with Adipose Tissue Function.

Cell Metab 2017 Sep;26(3):475-492.e7

Institute for Diabetes Research, Research Group Immune Tolerance in Diabetes, Helmholtz Diabetes Center at Helmholtz Zentrum München, 80939 Munich, Germany; German Center for Diabetes Research (DZD), 85764 Munich-Neuherberg, Germany. Electronic address:

Obesity and type 2 diabetes are associated with metabolic defects and adipose tissue inflammation. Foxp3 regulatory T cells (Tregs) control tissue homeostasis by counteracting local inflammation. However, if and how T cells interlink environmental influences with adipocyte function remains unknown. Here, we report that enhancing sympathetic tone by cold exposure, beta3-adrenergic receptor (ADRB3) stimulation or a short-term high-calorie diet enhances Treg induction in vitro and in vivo. CD4 T cell proteomes revealed higher expression of Foxp3 regulatory networks in response to cold or ADRB3 stimulation in vivo reflecting Treg induction. Specifically, Ragulator-interacting protein C17orf59, which limits mTORC1 activity, was upregulated in CD4 T cells by either ADRB3 stimulation or cold exposure, suggesting contribution to Treg induction. By loss- and gain-of-function studies, including Treg depletion and transfers in vivo, we demonstrated that a T cell-specific Stat6/Pten axis links cold exposure or ADRB3 stimulation with Foxp3 Treg induction and adipose tissue function. Our findings offer a new mechanistic model in which tissue-specific Tregs maintain adipose tissue function.
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http://dx.doi.org/10.1016/j.cmet.2017.08.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5627977PMC
September 2017

Resolution of inflammation by interleukin-9-producing type 2 innate lymphoid cells.

Nat Med 2017 Aug 17;23(8):938-944. Epub 2017 Jul 17.

Department of Internal Medicine 3-Rheumatology and Immunology, Friedrich Alexander University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany.

Inflammatory diseases such as arthritis are chronic conditions that fail to resolve spontaneously. While the cytokine and cellular pathways triggering arthritis are well defined, those responsible for the resolution of inflammation are incompletely characterized. Here we identified interleukin (IL)-9-producing type 2 innate lymphoid cells (ILC2s) as the mediators of a molecular and cellular pathway that orchestrates the resolution of chronic inflammation. In mice, the absence of IL-9 impaired ILC2 proliferation and activation of regulatory T (T) cells, and resulted in chronic arthritis with excessive cartilage destruction and bone loss. In contrast, treatment with IL-9 promoted ILC2-dependent T activation and effectively induced resolution of inflammation and protection of bone. Patients with rheumatoid arthritis in remission exhibited high numbers of IL-9 ILC2s in joints and the circulation. Hence, fostering IL-9-mediated ILC2 activation may offer a novel therapeutic approach inducing resolution of inflammation rather than suppression of inflammatory responses.
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http://dx.doi.org/10.1038/nm.4373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5575995PMC
August 2017

Chemically induced mouse models of acute and chronic intestinal inflammation.

Nat Protoc 2017 Jul 1;12(7):1295-1309. Epub 2017 Jun 1.

Department of Medicine 1, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.

Inflammatory bowel diseases (IBDs) result in diarrhea and abdominal pain with further potential complications such as tissue fibrosis and stenosis. Animal models help in understanding the immunopathogenesis of IBDs and in the design of novel therapeutic concepts. Here we present an updated version of a protocol we published in 2007 for key models of acute and chronic forms of colitis induced by 2,4,6-trinitro-benzene sulfonic acid (TNBS), oxazolone and dextran sulfate sodium (DSS). This protocol update describes an adaptation of the existing protocol that modifies the technique. This protocol has been used to generate improved mouse models that better reflect the nature of IBDs in humans. In TNBS and oxazolone colitis models, topical administration of hapten reagents results in T-cell-mediated immunity against haptenized proteins and luminal antigens. By contrast, to generate DSS colitis models, mice orally receive DSS, causing death of epithelial cells, compromising barrier function and causing subsequent inflammation. The analysis of the acute colitis models can be performed within 1-2 weeks, whereas that of the chronic models may take 2-4 months. The strengths of the acute models are that they are based on the analysis of short-lasting barrier alterations, innate immune effects and flares. The advantages of the chronic models are that they may offer better insight into adaptive immunity and complications such as neoplasia and tissue fibrosis. The protocol requires basic skills in laboratory animal research.
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http://dx.doi.org/10.1038/nprot.2017.044DOI Listing
July 2017

Reply to "Tolerogenic insulin peptide therapy precipitates type 1 diabetes".

J Exp Med 2017 Jul 23;214(7):2157-2159. Epub 2017 May 23.

Harvard Medical School (em.), Boston, MA.

In this issue of JEM, Bergman et al. (https://doi.org/10.1084/jem.20160471) challenge the data published in our previous JEM paper on the preventive effect of tolerogenic vaccination with a strong agonist insulin mimetope in type 1 diabetes. Here, we provide a response to these data and suggest that appropriate subimmunogenic conditions are required to induce Foxp3 regulatory T cell conversion.
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http://dx.doi.org/10.1084/jem.20170285DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5501570PMC
July 2017

Elevated levels of Bcl-3 inhibits Treg development and function resulting in spontaneous colitis.

Nat Commun 2017 04 28;8:15069. Epub 2017 Apr 28.

Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg, University of Mainz, Obere Zahlbarer Str 67, 55131 Mainz, Germany.

Bcl-3 is an atypical NF-κB family member that regulates NF-κB-dependent gene expression in effector T cells, but a cell-intrinsic function in regulatory T (Treg) cells and colitis is not clear. Here we show that Bcl-3 expression levels in colonic T cells correlate with disease manifestation in patients with inflammatory bowel disease. Mice with T-cell-specific overexpression of Bcl-3 develop severe colitis that can be attributed to defective Treg cell development and function, leading to the infiltration of immune cells such as pro-inflammatory γδT cells, but not αβ T cells. In Treg cells, Bcl-3 associates directly with NF-κB p50 to inhibit DNA binding of p50/p50 and p50/p65 NF-κB dimers, thereby regulating NF-κB-mediated gene expression. This study thus reveals intrinsic functions of Bcl-3 in Treg cells, identifies Bcl-3 as a potential prognostic marker for colitis and illustrates the mechanism by which Bcl-3 regulates NF-κB activity in Tregs to prevent colitis.
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http://dx.doi.org/10.1038/ncomms15069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5414353PMC
April 2017

Activation of Epithelial Signal Transducer and Activator of Transcription 1 by Interleukin 28 Controls Mucosal Healing in Mice With Colitis and Is Increased in Mucosa of Patients With Inflammatory Bowel Disease.

Gastroenterology 2017 07 23;153(1):123-138.e8. Epub 2017 Mar 23.

Medical Clinic 1, Department of Medicine, University Hospital Erlangen, University of Erlangen-Nuremberg, Erlangen, Germany; Ludwig Demling Endoscopy Center of Excellence, University of Erlangen-Nuremberg, Erlangen, Germany. Electronic address:

Background & Aims: We investigated the roles of interleukin 28A (also called IL28A or interferon λ2) in intestinal epithelial cell (IEC) activation, studying its effects in mouse models of inflammatory bowel diseases (IBD) and intestinal mucosal healing.

Methods: Colitis was induced in C57BL/6JCrl mice (controls), mice with IEC-specific disruption of Stat1 (Stat1IEC-KO), mice with disruption of the interferon λ receptor 1 gene (Il28ra), and mice with disruption of the interferon regulatory factor 3 gene (Irf3), with or without disruption of Irf7 (Irf7). We used high-resolution mini-endoscopy and in vivo imaging methods to assess colitis progression. We used 3-dimensional small intestine and colon organoids, along with RNA-Seq and gene ontology methods, to characterize the effects of IL28 on primary IECs. We studied the effects of IL28 on the human intestinal cancer cell line Caco-2 in a wound-healing assay, and in mice colon wounds. Colonic biopsies and resected tissue from patients with IBD (n = 62) and patients without colon inflammation (controls, n = 23) were analyzed by quantitative polymerase chain rection to measure expression of IL28A, IL28RA, and other related cytokines; biopsy samples were also analyzed by immunofluorescence to identify sources of IL28 production. IECs were isolated from patient tissues and incubated with IL28; signal transducer and activator of transcription 1 (STAT1) phosphorylation was measured by immunoblots and confocal imaging.

Results: Lamina propria cells in colon tissues of patients with IBD, and mice with colitis, had increased expression of IL28 compared with controls; levels of IL28R were increased in the colonic epithelium of patients with IBD and mice with colitis. Administration of IL28 induced phosphorylation of STAT1 in primary human and mouse IECs, increasing with dose. Il28ra, Irf3, Irf3Irf7, as well as Stat1IEC-KO mice, developed more severe colitis after administration of dextran sulfate sodium than control mice, with reduced epithelial restitution. Il28ra and Stat1IEC-KO mice also developed more severe colitis in response to oxazolone than control mice. We found IL28 to induce phosphorylation (activation) of STAT1 in epithelial cells, leading to their proliferation in organoid culture. Administration of IL28 to mice with induced colonic wounds promoted mucosal healing.

Conclusions: IL28 controls proliferation of IECs in mice with colitis and accelerates mucosal healing by activating STAT1. IL28 might be developed as a therapeutic agent for patients with IBD.
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http://dx.doi.org/10.1053/j.gastro.2017.03.015DOI Listing
July 2017

Defective IL-23/IL-17 Axis Protects p47phox-/- Mice from Colon Cancer.

Front Immunol 2017 27;8:44. Epub 2017 Jan 27.

pharmazentrum frankfurt/ZAFES, Goethe University , Frankfurt , Germany.

In the colon, a sophisticated balance between immune reaction and tolerance is absolutely required. Dysfunction may lead to pathologic phenotypes ranging from chronic inflammatory processes to cancer development. Two prominent modulators of colon inflammation are represented by the closely related cytokines interleukin (IL)-12 and IL-23, which initiate adaptive Th1 and Th17 immune responses, respectively. In this study, we investigated the impact of the NADPH oxidase protein p47phox, which negatively regulates IL-12 in dendritic cells, on colon cancer development in a colitis-associated colon cancer model. Initially, we found that IL-12-/- mice developed less severe colitis but are highly susceptible to colon cancer. By contrast, p47phox-/- mice showed lower tumor scores and fewer high grade tumors than wild-type (WT) littermates. Treatment with toll-like receptor 9 ligand CpG2216 significantly enhanced colitis in p47phox-/- mice, whereas tumor growth was simultaneously reduced. In tumor tissue of p47phox-/- mice, the IL-23/IL-17 axis was crucially hampered. IL-23p19 protein expression in tumor tissue correlated with tumor stage. Reconstitution of WT mice with IL-23p19-/- bone marrow protected these mice from colon cancer, whereas transplantation of WT hematopoiesis into IL-23p19-/- mice increased the susceptibility to tumor growth. Our study strengthens the divergent role of IL-12 and IL-23 in colon cancer development. With the characterization of p47phox as a novel modulator of both cytokines our investigation introduces a promising new target for antitumor strategies.
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http://dx.doi.org/10.3389/fimmu.2017.00044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5271172PMC
January 2017

Monitoring of Chemically Induced Colitis.

Methods Mol Biol 2017 ;1559:297-309

Department of Medicine 1, University of Erlangen-Nuremberg, Campus for medical research, Hartmannstr.14, 91052, Erlangen, Germany.

Inflammation is a common symptom of inflammatory bowel disease (IBD). Actually, many experimental models of colitis exist and try to mimic the human situation in order to understand the pathogenesis of Crohn's disease and ulcerative colitis. These experimental models of inflammation can be characterized by specific parameters, which illustrate the proceeding inflammatory process. By use of these models potentially new reagents for improved therapeutic approaches can be analyzed. Here, we describe the TNBS-mediated colitis model and specify different parameters for the detailed characterization of the inflammatory process in experimental colitis models.
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http://dx.doi.org/10.1007/978-1-4939-6786-5_20DOI Listing
January 2018

Th9 cells in inflammatory bowel diseases.

Semin Immunopathol 2017 01 11;39(1):89-95. Epub 2016 Nov 11.

Department of Medicine 1, Kussmaul Campus for Medical Research, Ludwig Demling Endoscopy Center of Excellence, University of Erlangen-Nürnberg, Erlangen, Germany.

Inflammatory bowel diseases are chronic, relapsing, immunologically mediated disorders of the gastrointestinal tract. Emerging evidence suggests a critical functional role of transcription factors and T cell-related cytokines in ulcerative colitis and Crohn's disease. Gut-residing T cells from patients with inflammatory bowel disease produce high amounts of IL-9. Experimental models of colitis highlighted that IL-9-producing T cells critically interfered with an intact barrier function of the intestinal epithelium by impacting cellular proliferation and tight junction molecules. The blockade of IL-9 was suited to significantly ameliorate the disease activity and severity in experimental models of inflammatory bowel disease thereby suggesting that targeting IL-9 might function as a novel targeted approach for therapy.
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http://dx.doi.org/10.1007/s00281-016-0603-zDOI Listing
January 2017

miRNA92a targets KLF2 and the phosphatase PTEN signaling to promote human T follicular helper precursors in T1D islet autoimmunity.

Proc Natl Acad Sci U S A 2016 10 10;113(43):E6659-E6668. Epub 2016 Oct 10.

Institute for Diabetes Research, Independent Young Investigator Group Immune Tolerance in Type 1 Diabetes, Helmholtz Diabetes Center at Helmholtz Zentrum München, 80939 Munich, Germany; Deutsches Zentrum für Diabetesforschung, 85764 Munich, Germany;

Aberrant immune activation mediated by T effector cell populations is pivotal in the onset of autoimmunity in type 1 diabetes (T1D). T follicular helper (TFH) cells are essential in the induction of high-affinity antibodies, and their precursor memory compartment circulates in the blood. The role of TFH precursors in the onset of islet autoimmunity and signaling pathways regulating their differentiation is incompletely understood. Here, we provide direct evidence that during onset of islet autoimmunity, the insulin-specific target T-cell population is enriched with a C-X-C chemokine receptor type 5 (CXCR5)CD4 TFH precursor phenotype. During onset of islet autoimmunity, the frequency of TFH precursors was controlled by high expression of microRNA92a (miRNA92a). miRNA92a-mediated TFH precursor induction was regulated by phosphatase and tension homolog (PTEN) - phosphoinositol-3-kinase (PI3K) signaling involving PTEN and forkhead box protein O1 (Foxo1), supporting autoantibody generation and triggering the onset of islet autoimmunity. Moreover, we identify Krueppel-like factor 2 (KLF2) as a target of miRNA92a in regulating human TFH precursor induction. Importantly, a miRNA92a antagomir completely blocked induction of human TFH precursors in vitro. More importantly, in vivo application of a miRNA92a antagomir to nonobese diabetic (NOD) mice with ongoing islet autoimmunity resulted in a significant reduction of TFH precursors in peripheral blood and pancreatic lymph nodes. Moreover, miRNA92a antagomir application reduced immune infiltration and activation in pancreata of NOD mice as well as humanized NOD Scid IL2 receptor gamma chain knockout (NSG) human leucocyte antigen (HLA)-DQ8 transgenic animals. We therefore propose that miRNA92a and the PTEN-PI3K-KLF2 signaling network could function as targets for innovative precision medicines to reduce T1D islet autoimmunity.
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http://dx.doi.org/10.1073/pnas.1606646113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5087025PMC
October 2016

Rectal Delivery of a DNAzyme That Specifically Blocks the Transcription Factor GATA3 and Reduces Colitis in Mice.

Gastroenterology 2017 01 14;152(1):176-192.e5. Epub 2016 Sep 14.

Department of Medicine, University of Erlangen-Nürnberg, Kussmaul Research Campus, Erlangen, Germany. Electronic address:

Background & Aims: GATA3 is a transcription factor that regulates T-cell production of cytokines. We investigated the role of GATA3 in development of colitis in mice.

Methods: We performed quantitative polymerase chain reaction and immunofluorescence analyses of colon tissues from patients with Crohn's disease (n = 61) or ulcerative colitis (UC, n = 74) or from patients without inflammatory bowel diseases (n = 22), to measure levels of GATA3. Colitis was induced by administration of oxazolone or 2,4,6-trinitrobenzenesulfonic acid to control mice, mice with T-cell-specific deletion of GATA3, and mice with deletion of tumor necrosis factor receptor (TNFR) 1 and TNFR2 (TNFR double knockouts); some mice were given a GATA3-specific DNAzyme (hgd40) or a control DNAzyme via intrarectal administration, or systemic injections of an antibody to TNF before or during sensitization and challenge phase of colitis induction. Colon tissues were collected and immunofluorescence and histochemical analyses were performed. Lamina propria mononuclear cells and T cells were isolated and analyzed by flow cytometry or cytokine assays. Colonic distribution of labeled DNAzyme and inflammation were monitored by in vivo imaging (endoscopy) of mice.

Results: Levels of GATA3 messenger RNA were higher in colon tissues from patients with UC, but not ileal Crohn's disease, than control tissues; levels of GATA3 correlated with levels of inflammatory cytokines (interleukin [IL] 9, IL17A, IL6, IL5, IL4, IL13, and TNF). We observed increased expression of GATA3 by lamina propria T cells from mice with colitis compared with controls. Mice with T-cell-specific deletion of GATA3 did not develop colitis and their colonic tissues did not produce inflammatory cytokines (IL6, IL9, or IL13). The DNAzyme hgd40 inhibited expression of GATA3 messenger RNA by unstimulated and stimulated T cells, and distributed throughout the inflamed colons of mice with colitis. Colon tissues from mice given hgd40 had reduced expression of GATA3 messenger RNA, compared with mice given a control DNAzyme. Mice given hgd40 did not develop colitis after administration of oxazolone or 2,4,6-trinitrobenzenesulfonic acid; lamina propria cells from these mice expressed lower levels of IL6, IL9, and IL13 than cells from mice given the control DNAzyme. Mini-endoscopic images revealed that hgd40 and anti-TNF reduced colon inflammation over 3 days; hgd40 reduced colitis in TNFR double-knockout mice.

Conclusions: Levels of GATA3 are increased in patients with UC and correlate with production of inflammatory cytokines in mice and humans. A DNAzyme that prevents expression of GATA3 reduces colitis in mice, independently of TNF, and reduces levels of cytokines in the colon. This DNAzyme might be developed for treatment of patients with UC.
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http://dx.doi.org/10.1053/j.gastro.2016.09.005DOI Listing
January 2017

Oxazolone-Induced Colitis as a Model of Th2 Immune Responses in the Intestinal Mucosa.

Methods Mol Biol 2016 ;1422:253-61

Department of Medicine 1, University of Erlangen-Nuremberg, Campus for Medical Research, Hartmannstr. 14, 91052, Erlangen, Germany.

Murine models of intestinal inflammation have been widely used in biomedical research. Similarities in anatomy and physiology between such murine models and patients with inflammatory bowel diseases may allow a better understanding of the pathogenesis of Crohn's disease and ulcerative colitis. Additionally, models of intestinal inflammation may be used for the analysis of potentially new therapeutic agents. One key class of models consists of chemically induced inflammation models. Within this group, colitis induced by the haptenizing agent oxazolone is an important model that results in induction of acute or chronic inflammation of the large bowel. Here, we describe the induction and the analysis of this experimental colitis model.
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http://dx.doi.org/10.1007/978-1-4939-3603-8_23DOI Listing
December 2017

Epicutaneous and Oral Low-Zone Tolerance Protects from Colitis in Mice.

J Invest Dermatol 2016 09 17;136(9):1831-1839. Epub 2016 May 17.

Department of Dermatology, University Medical Center, Johannes Gutenberg-University of Mainz, Mainz, Germany. Electronic address:

Tolerance to environmental antigens that encounter the organism at interfaces like skin or gut prevents deleterious systemic immune responses. The aim of this study was to analyze whether and how low doses of haptens, by entry through the skin or gastrointestinal tract, affect the outcome of the predominantly Th1/Th17-mediated 2,4,6-trinitro-benzenesulfonic acid-induced colitis, which mimics an autoimmune bowl disease in man. Epicutaneous and oral applications of low doses of the allergen resulted in the induction of low-zone tolerance (LZT) and protected from colitis development, demonstrated by a significantly reduced inflammatory response of the gut in vivo. In line with this observation, we found a significantly diminished Th1/Th17-mediated T cell response and reduced T cell proliferation after both tolerance regimes, indicating that epicutaneous LZT is just as well efficient as oral tolerance in prevention of a gut-associated inflammatory immune response. Use of a second, unrelated hapten for LZT induction revealed an antigen-specific tolerance mechanism. Intriguingly, in the absence of hapten-activated CD4(+)CD25(+)Foxp3(+) regulatory T cells and IL-10, epicutaneous and oral LZT failed to abrogate the development of the intestinal inflammation. In conclusion, this study highlights in particular epicutaneous immunotherapies in the form of LZT through activation of CD4(+)CD25(+)Foxp3(+) regulatory T cells as treatment strategies for inflammatory, allergic, or autoimmune diseases.
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http://dx.doi.org/10.1016/j.jid.2016.04.037DOI Listing
September 2016

Budesonide Loaded PLGA Nanoparticles for Targeting the Inflamed Intestinal Mucosa--Pharmaceutical Characterization and Fluorescence Imaging.

Pharm Res 2016 May 30;33(5):1085-92. Epub 2015 Dec 30.

Biopharmaceutics and Pharmaceutical Technology, Saarland University, Campus A4.1, 66123, Saarbrücken, Germany.

Purpose: The purpose of this study was to evaluate the specifically targeted efficiency of budesonide loaded PLGA nanoparticles for the treatment of inflammatory bowel disease (IBD).

Methods: The nanoparticles were prepared by an oil/water (O/W) emulsion evaporation technique. The nanoparticles were characterized for their size, shape and in vitro drug release profile. Solid state characterization was carried out by differential scanning calorimetry (DSC) and X-ray Power diffraction (XPRD). In order to evaluate the targeted efficiency of nanoparticles, a particle localization study in the healthy and in the inflamed colon was determined in vivo. These data were complemented by cryo-sections.

Results: Nanoparticles were 200 ± 05 nm in size with a smooth and spherical shape. The encapsulation efficiency was around 85 ± 3.5%, which was find-out by both, direct and indirect methods. Release of budesonide from the nanoparticles showed a biphasic release profile with an initial burst followed by sustained release. XPRD data revealed that the drug in the polymer matrix existed in crystalline state. Nanoparticles accumulation in inflamed tissues was evaluated by in-vivo imaging system and it was found that particles are accumulated in abundance at the site of inflammation when compared to the healthy group.

Conclusion: The study demonstrates that the budesonide loaded PLGA nanoparticles are an efficient delivery system for targeted drug delivery to the inflamed intestinal mucosa.
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http://dx.doi.org/10.1007/s11095-015-1852-6DOI Listing
May 2016

Activated glycoprotein A repetitions predominant (GARP)-expressing regulatory T cells inhibit allergen-induced intestinal inflammation in humanized mice.

J Allergy Clin Immunol 2015 Jul;136(1):159-68

Department of Dermatology, University Hospital Erlangen, University Erlangen-Nürnberg, Erlangen, Germany. Electronic address:

Background: Recently, we developed a humanized mouse model of allergen-induced IgE-dependent gut inflammation in PBMC-engrafted immunodeficient mice.

Objective: In the present study, we wanted to investigate the role of regulatory T (Treg) cells and their activation status in this model.

Methods: Nonobese diabetic-severe combined immunodeficiency-γc(-/-) mice were injected intraperitoneally with human PBMCs from allergic donors together with the respective allergen or NaCl as control in the presence or absence of different concentrations of CD4(+)CD25(+) Treg cells of the same donor. After an additional allergen boost 1 week later, mice were challenged with the allergen rectally on day 21 and gut inflammation was monitored by a high-resolution video mini-endoscopic system evaluating translucency, granularity, fibrin production, vascularity, and stool.

Results: Allergen-specific human IgE in mouse sera, which was detectable only in PBMC plus allergen-treated mice, was strongly inhibited by coinjection of Treg cells at a ratio of at least 1:10. Consequently, the presence of Treg cells significantly decreased IgE-dependent allergen-induced gut inflammation after rectal allergen challenge. In addition, Treg cells reduced allergen-specific proliferation and cytokine production of recovered human CD4(+) T cells in vitro. Activation of Treg cells before injection further increased all inhibitory effects. Prevention of gut inflammation also occurred by the administration of glycoprotein A repetitions predominant, a molecule expressed by activated Treg cells, whereas its blockade completely abrogated inhibition by Treg cells.

Conclusions: These results demonstrate that allergen-specific gut inflammation in human PBMC-engrafted mice can be avoided by enhancing the numbers or activity of autologous Treg cells, which is of great interest for therapeutic intervention of allergic diseases of the intestine.
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http://dx.doi.org/10.1016/j.jaci.2015.04.020DOI Listing
July 2015

IL-9 regulates intestinal barrier function in experimental T cell-mediated colitis.

Tissue Barriers 2015 3;3(1-2):e983777. Epub 2015 Apr 3.

Department of Medicine 1; University of Erlangen-Nuremberg; Kussmaul Research Campus ; Erlangen, Germany.

As previous studies suggested that IL-9 may control intestinal barrier function, we tested the role of IL-9 in experimental T cell-mediated colitis induced by the hapten reagent 2,4,6-trinitrobenzenesulfonic acid (TNBS). The deficiency of IL-9 suppressed TNBS-induced colitis and led to lower numbers of PU.1 expressing T cells in the lamia propria, suggesting a regulatory role for Th9 cells in the experimental TNBS colitis model. Since IL-9 is known to functionally alter intestinal barrier function in colonic inflammation, we assessed the expression of tight junction molecules in intestinal epithelial cells of TNBS-inflamed mice. Therefore we made real-time PCR analyses for tight junction molecules in the inflamed colon from wild-type and IL-9 KO mice, immunofluorescent stainings and investigated the expression of junctional proteins directly in intestinal epithelial cells of TNBS-inflamed mice by Western blot studies. The results demonstrated that sealing proteins like occludin were up regulated in the colon of inflamed IL-9 KO mice. In contrast, the tight junction protein Claudin1 showed lower expression levels when IL-9 is absent. Surprisingly, the pore-forming molecule Claudin2 revealed equal expression in TNBS-treated wild-type and IL-9-deficient animals. These results illustrate the pleiotropic functions of IL-9 in changing intestinal permeability in experimental colitis. Thus, modulation of IL-9 function emerges as a new approach for regulating barrier function in intestinal inflammation.
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http://dx.doi.org/10.4161/21688370.2014.983777DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4372018PMC
April 2015

Cyclosporine A regulates pro-inflammatory cytokine production in ulcerative colitis.

Arch Immunol Ther Exp (Warsz) 2015 Feb 26;63(1):53-63. Epub 2014 Aug 26.

Medical Clinic 1, Kussmaul Research Campus, Friedrich-Alexander University of Erlangen-Nuremberg, Hartmannstr. 14, 91052, Erlangen, Germany.

Crohn's disease (CD) and ulcerative colitis (UC) are the two major forms of inflammatory bowel diseases (IBD), which are defined as relapsing inflammations of the gastrointestinal tract. Cyclosporine A (CsA) is a potential rescue treatment to avoid colectomy in severe steroid-refractory UC patients. The molecular mechanism of action of CsA in UC is nevertheless still not well understood. The aim of this study was to investigate the effect of CsA on a possible modulation of cytokine production by peripheral blood mononuclear cells (PBMCs) of controls and patients with UC or CD. Upon CsA treatment, analyses of cytokine levels revealed a significant reduction of IL-13 expression in PBMCs from patients with UC, whereas other cytokine expression levels remained unaffected. To address the question whether CsA treatment impinges on the induction of cell death, apoptosis assays were performed using CD4(+) T cells from peripheral blood of patients suffering from either UC or CD. It became clear that CsA treatment resulted in a specific induction of apoptosis in samples from controls and patients with UC but not with CD. Apoptosis induction was not mediated via the mitochondrial apoptosis pathway. The present data support the concept that CsA treatment modulates pro-inflammatory cytokine production and T cell survival in UC via the induction of apoptosis and might therefore help to explain the clinical efficacy of CsA in patients with UC.
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http://dx.doi.org/10.1007/s00005-014-0309-7DOI Listing
February 2015