Research at the UKE?
DE
Intestinal immune regulation
The intestine plays a key role in controlling the immune response. By understanding the interplay between the microbiota, the tissue and the immune cells, we can pave the way for future therapies for chronic inflammatory diseases and cancer.
“The intestine plays a key role in controlling the immune response. By understanding the interplay between the microbiota, the tissue and the immune cells, we can pave the way for future therapies for chronic inflammatory diseases and cancer.”
Prof. Dr. Samuel Huber
Head of Molecular Gastroenterology and Immunology
Project details and goals
Inflammation is fundamental to promote tissue regeneration upon injury, and, in turn, the resolution of the immune response. Physiological tissue regeneration depends on fine-tuned interactions between the immune system, the tissue, and the microbiota. However, the complex communication between these three components and the molecules that mediate it are unclear. We hypothesize that inflammatory bowel disease (IBD) and colorectal cancer (CRC) are a consequence of a miscommunication between these components. Furthermore, this regulation also affects diseases in extra-intestinal organs. Thus, we hypothesize that by controlling the intestinal immune system we can prevent or cure chronic inflammatory diseases and even cancer also in extra-intestinal organs, such as the liver and kidney.
This hypothesis is based on recent findings by others and by us showing that the intestine plays a key role in modulating the balance between regulatory T cells, such as Foxp3+ Treg, Tr1 cells, and effector T cells, thereby influencing Immune-mediated inflammatory diseases in several organs. However, most T cells and cytokines, such as IL-22, have both context dependent pathogenic and protective functions. The right balance must be achieved. Thus, one key aspect of our study is to dissect complex biological systems in order to regulate rather than to block immune responses in order to facilitate the beneficial functions of these cells and cytokines.
Current projects
Project 1: IL-22 – IL-22BP: Spatio-Temporal Regulation of Inflammation and Tissue Regeneration
Interleukin-22 (IL-22) is one key orchestrator of this communication: It is produced by immune cells and by acting on intestinal epithelial cells, it modulates the composition of the microbiota and promotes tissue regeneration. However, IL-22 can also promote both chronic inflammation and cancer. Exactly what regulates these paradoxical effects remains unclear. Of note, there is an endogenous inhibitor of IL-22, namely IL-22 binding protein (IL-22BP), which blocks IL-22 activity. We hypothesize that a misguided spatio-temporal regulation of the IL-22 – IL-22BP axis is the cause of pathogenic effects of IL-22.
In particular, we will analyse: (i) the location, and the functional and molecular heterogeneity; (ii) the origin and fate of IL-22 and IL-22BP producing immune cells; and (iii) the role of the microbiota in regulating them. To this end, we will use new transgenic and gnotobiotic mouse models, single cell RNA sequencing and human samples.
In short, by studying the IL-22 - IL-22BP axis, we will understand how the complex interactions between the immune system, the tissue, and the microbiota lead to either physiological or pathological tissue regeneration. This will provide the basis for therapies controlling inflammation and tissue regeneration in a spatio-temporal manner.
Influence of environment factors on CD4+ T-helper cell plasticity and function
We aim to understand how different factors influence the phenotype and function of immune cells and their cytokine products. We are particularly focused on Inflammatory Bowel Diseases (IBD) and Colorectal Cancer (CRC). Among different factors, our focus is on the intestinal microbiota, dietary components such as gluten, and environmental plastics present in everyday products. By combining high-throughput techniques such as single-cell sequencing and microbiota sequencing with supervised techniques such as flow cytometry and qPCR, we analyze human samples collected from individuals with IBD before and after various biological treatments and dietary interventions. These diseases are also studied using animal models, e.g. with different but defined microbiota: SPF microbiota, ‘Wildling’ mice (with naturally occurring pathogens) as well as patient-specific gnotobiotic mice. We are furthermore interested in how the intestine can shape immune responses in other organs (such as the liver) and systemically. One of our particular focuses is understanding the role of individual T cells and cytokines in controlling the response to immune-checkpoint inhibitor treatment (both in terms of the oncological response and the development of side effects – immune related adverse events).
Regulatory T cells in Immune mediated inflammatory diseases
Regulatory T cells (Treg) play a pivotal role in maintaining immune homeostasis and controlling chronic inflammation and autoimmunity. In the intestine, Treg are essential for maintaining the delicate balance between the immune system and the gut microbiota, thereby preventing conditions such as inflammatory bowel disease (IBD) and promoting tolerance to beneficial gut bacteria, ensuring intestinal health. Similarly, in extra-intestinal tissues like the liver and central nervous system, Treg mitigate inflammation in chronic diseases such as primary sclerosing cholangitis (PSC) and multiple sclerosis (MS) by controlling autoreactive immune cells to prevent tissue damage and maintain organ function. Our research aims to elucidate the mechanisms by which Treg control both intra- and extra-intestinal inflammation using basic mouse models and translational approaches. We assess their regulatory function in various tissue environments, on other immune cells such as Th17 cells, and the involved signaling pathways. This knowledge is crucial for developing effective treatments for inflammatory diseases, potentially leading to improved management and cure of autoimmune and chronic inflammatory conditions.
Influence of the microbiota on intestinal dendritic cells and its impact on Inflammatory Bowel Disease
Intestinal dendritic cells (DCs) play a central role in maintaining homeostasis and initiating adaptive immune responses within the gastrointestinal tract. Not only must they interact with the complex microbial milieu but at the same time prime and modulate the differentiation of T cells. So far, the study of intestinal DCs has been encumbered by their limited numbers and phenotypic overlap with other myeloid cells. Thus, the precise influence of the local microenvironment, and in particular the microbiota, on the functional and phenotypic attributes of intestinal DCs is not completely understood. Studying how intestinal DCs are influenced by their environment and how it affects their interaction with T cells will provide insights into the mechanisms involved in intestinal homeostasis and diseases such as Inflammatory Bowel Disease (IBD).
Publications 2024
Abstract
Adeno-associated virus (AAV) is a promising in vivo gene delivery platform showing advantages in delivering therapeutic molecules to difficult or undruggable cells. However, natural AAV serotypes have insufficient transduction specificity and efficiency in kidney cells. Here, we developed an evolution-directed selection protocol for renal glomeruli and identified what we believe to be a new vector termed AAV2-GEC that specifically and efficiently targets the glomerular endothelial cells (GEC) after systemic administration and maintains robust GEC tropism in healthy and diseased rodents. AAV2-GEC-mediated delivery of IdeS, a bacterial antibody-cleaving proteinase, provided sustained clearance of kidney-bound antibodies and successfully treated antiglomerular basement membrane glomerulonephritis in mice. Taken together, this study showcases the potential of AAV as a gene delivery platform for challenging cell types. The development of AAV2-GEC and its successful application in the treatment of antibody-mediated kidney disease represents a significant step forward and opens up promising avenues for kidney medicine.
Abstract
Background: Minimal change disease and primary focal segmental glomerulosclerosis in adults, along with idiopathic nephrotic syndrome in children, are immune-mediated podocytopathies that lead to nephrotic syndrome. Autoantibodies targeting nephrin have been found in patients with minimal change disease, but their clinical and pathophysiological roles are unclear.
Methods: We conducted a multicenter study to analyze antinephrin autoantibodies in adults with glomerular diseases, including minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, IgA nephropathy, antineutrophil cytoplasmic antibody-associated glomerulonephritis, and lupus nephritis, as well as in children with idiopathic nephrotic syndrome and in controls. We also created an experimental mouse model through active immunization with recombinant murine nephrin.
Results: The study included 539 patients (357 adults and 182 children) and 117 controls. Among the adults, antinephrin autoantibodies were found in 46 of the 105 patients (44%) with minimal change disease, 7 of 74 (9%) with primary focal segmental glomerulosclerosis, and only in rare cases among the patients with other conditions. Of the 182 children with idiopathic nephrotic syndrome, 94 (52%) had detectable antinephrin autoantibodies. In the subgroup of patients with active minimal change disease or idiopathic nephrotic syndrome who were not receiving immunosuppressive treatment, the prevalence of antinephrin autoantibodies was as high as 69% and 90%, respectively. At study inclusion and during follow-up, antinephrin autoantibody levels were correlated with disease activity. Experimental immunization induced a nephrotic syndrome, a minimal change disease-like phenotype, IgG localization to the podocyte slit diaphragm, nephrin phosphorylation, and severe cytoskeletal changes in mice.
Conclusions: In this study, circulating antinephrin autoantibodies were common in patients with minimal change disease or idiopathic nephrotic syndrome and appeared to be markers of disease activity. Their binding at the slit diaphragm induced podocyte dysfunction and nephrotic syndrome, which highlights their pathophysiological significance. (Funded by Deutsche Forschungsgemeinschaft and others.).
Abstract
Objective: There is a strong clinical association between IBD and primary sclerosing cholangitis (PSC), a chronic disease of the liver characterised by biliary inflammation that leads to strictures and fibrosis. Approximately 60% – 80% of people with PSC will also develop IBD (PSC-IBD). One hypothesis explaining this association would be that PSC drives IBD. Therefore, our aim was to test this hypothesis and to decipher the underlying mechanism.
Design: Colitis severity was analysed in experimental mouse models of colitis and sclerosing cholangitis, and people with IBD and PSC-IBD. Foxp3+ Treg-cell infiltration was assessed by qPCR and flow cytometry. Microbiota profiling was carried out from faecal samples of people with IBD, PSC-IBD and mouse models recapitulating these diseases. Faecal microbiota samples collected from people with IBD and PSC-IBD were transplanted into germ-free mice followed by colitis induction.
Results: We show that sclerosing cholangitis attenuated IBD in mouse models. Mechanistically, sclerosing cholangitis causes an altered intestinal microbiota composition, which promotes Foxp3+ Treg-cell expansion, and thereby protects against IBD. Accordingly, sclerosing cholangitis promotes IBD in the absence of Foxp3+ Treg cells. Furthermore, people with PSC-IBD have an increased Foxp3+ expression in the colon and an overall milder IBD severity. Finally, by transplanting faecal microbiota into gnotobiotic mice, we showed that the intestinal microbiota of people with PSC protects against colitis.
Conclusion: This study shows that PSC attenuates IBD and provides a comprehensive insight into the mechanisms involved in this effect.
Abstract
Background & Aims: The liver is one of the organs most commonly affected by metastasis. The presence of liver metastases has been reported to be responsible for an immunosuppressive microenvironment and diminished immunotherapy efficacy. Herein, we aimed to investigate the role of IL-10 in liver metastasis and to determine how its modulation could affect the efficacy of immunotherapy in vivo.
Methods: To induce spontaneous or forced liver metastasis in mice, murine cancer cells (MC38) or colon tumor organoids were injected into the cecum or the spleen, respectively. Mice with complete and cell type-specific deletion of IL-10 and IL-10 receptor alpha were used to identify the source and the target of IL-10 during metastasis formation. Programmed death ligand 1 (PD-L1)-deficient mice were used to test the role of this checkpoint. Flow cytometry was applied to characterize the regulation of PD-L1 by IL-10.
Results: We found that Il10-deficient mice and mice treated with IL-10 receptor alpha antibodies were protected against liver metastasis formation. Furthermore, by using IL-10 reporter mice, we demonstrated that Foxp3+ regulatory T cells (Tregs) were the major cellular source of IL-10 in liver metastatic sites. Accordingly, deletion of IL-10 in Tregs, but not in myeloid cells, led to reduced liver metastasis. Mechanistically, IL-10 acted on Tregs in an autocrine manner, thereby further amplifying IL-10 production. Furthermore, IL-10 acted on myeloid cells, i.e. monocytes, and induced the upregulation of the immune checkpoint protein PD-L1. Finally, the PD-L1/PD-1 axis attenuated CD8-dependent cytotoxicity against metastatic lesions.
Conclusions: Treg-derived IL-10 upregulates PD-L1 expression in monocytes, which in turn reduces CD8+ T-cell infiltration and related antitumor immunity in the context of colorectal cancer-derived liver metastases. These findings provide the basis for future monitoring and targeting of IL-10 in colorectal cancer-derived liver metastases.
Impact and implications: Liver metastasis diminishes the effectiveness of immunotherapy and increases the mortality rate in patients with colorectal cancer. We investigated the role of IL-10 in liver metastasis formation and assessed its impact on the effectiveness of immunotherapy. Our data show that IL-10 is a pro-metastatic factor involved in liver metastasis formation and that it acts as a regulator of PD-L1. This provides the basis for future monitoring and targeting of IL-10 in colorectal cancer-derived liver metastasis.
Publications 2023
Abstract
Current therapies for Fabry disease are based on reversing intracellular accumulation of globotriaosylceramide (Gb3) by enzyme replacement therapy (ERT) or chaperone-mediated stabilization of the defective enzyme, thereby alleviating lysosomal dysfunction. However, their effect in the reversal of end-organ damage, like kidney injury and chronic kidney disease, remains unclear. In this study, ultrastructural analysis of serial human kidney biopsies showed that long-term use of ERT reduced Gb3 accumulation in podocytes but did not reverse podocyte injury. Then, a CRISPR/Cas9-mediated α-galactosidase knockout podocyte cell line confirmed ERT-mediated reversal of Gb3 accumulation without resolution of lysosomal dysfunction. Transcriptome-based connectivity mapping and SILAC-based quantitative proteomics identified α-synuclein (SNCA) accumulation as a key event mediating podocyte injury. Genetic and pharmacological inhibition of SNCA improved lysosomal structure and function in Fabry podocytes, exceeding the benefits of ERT. Together, this work reconceptualizes Fabry-associated cell injury beyond Gb3 accumulation, and introduces SNCA modulation as a potential intervention, especially for patients with Fabry nephropathy.
Abstract
Expansion microscopy physically enlarges biological specimens to achieve nanoscale resolution using diffraction-limited microscopy systems. However, optimal performance is usually reached using laser-based systems (for example, confocal microscopy), restricting its broad applicability in clinical pathology, as most centres have access only to light-emitting diode (LED)-based widefield systems. As a possible alternative, a computational method for image resolution enhancement, namely, super-resolution radial fluctuations (SRRF), has recently been developed. However, this method has not been explored in pathology specimens to date, because on its own, it does not achieve sufficient resolution for routine clinical use. Here, we report expansion-enhanced super-resolution radial fluctuations (ExSRRF), a simple, robust, scalable and accessible workflow that provides a resolution of up to 25 nm using LED-based widefield microscopy. ExSRRF enables molecular profiling of subcellular structures from archival formalin-fixed paraffin-embedded tissues in complex clinical and experimental specimens, including ischaemic, degenerative, neoplastic, genetic and immune-mediated disorders. Furthermore, as examples of its potential application to experimental and clinical pathology, we show that ExSRRF can be used to identify and quantify classical features of endoplasmic reticulum stress in the murine ischaemic kidney and diagnostic ultrastructural features in human kidney biopsies.
Abstract
Membranous nephropathy (MN) is an antibody-mediated autoimmune disease characterized by glomerular immune complexes containing complement components. However, both the initiation pathways and the pathogenic significance of complement activation in MN are poorly understood. Here, we show that components from all three complement pathways (alternative, classical and lectin) are found in renal biopsies from patients with MN. Proximity ligation assays to directly visualize complement assembly in the tissue reveal dominant activation via the classical pathway, with a close correlation to the degree of glomerular C1q-binding IgG subclasses. In an antigen-specific autoimmune mouse model of MN, glomerular damage and proteinuria are reduced in complement-deficient mice compared with wild-type littermates. Severe disease with progressive ascites, accompanied by extensive loss of the integral podocyte slit diaphragm proteins, nephrin and neph1, only occur in wild-type animals. Finally, targeted silencing of C3 using RNA interference after the onset of proteinuria significantly attenuates disease. Our study shows that, in MN, complement is primarily activated via the classical pathway and targeting complement components such as C3 may represent a promising therapeutic strategy.
Giannou, A.D., Kempski, J., Shiri, A.M., Lücke, J., Zhang, T., Zhao, L., Zazara, D.E., Cortesi, F., Riecken, K., Amezcua Vesely, M.C., et al. (2023). Tissue resident iNKT17 cells facilitate cancer cell extravasation in liver metastasis via interleukin-22. Immunity 56, 125-142.e12.
During metastasis, cancer cells invade, intravasate, enter the circulation, extravasate, and colonize target organs. Here, we examined the role of interleukin (IL)-22 in metastasis. Immune cell-derived IL-22 acts on epithelial tissues, promoting regeneration and healing upon tissue damage, but it is also associated with malignancy. Il22-deficient mice and mice treated with an IL-22 antibody were protected from colon-cancer-derived liver and lung metastasis formation, while overexpression of IL-22 promoted metastasis. Mechanistically, IL-22 acted on endothelial cells, promoting endothelial permeability and cancer cell transmigration via induction of endothelial aminopeptidase N. Multi-parameter flow cytometry and single-cell sequencing of immune cells isolated during cancer cell extravasation into the liver revealed iNKT17 cells as source of IL-22. iNKT-cell-deficient mice exhibited reduced metastases, which was reversed by injection of wild type, but not Il22-deficient, invariant natural killer T (iNKT) cells. IL-22-producing iNKT cells promoting metastasis were tissue resident, as demonstrated by parabiosis. Thus, IL-22 may present a therapeutic target for prevention of metastasis.
Previous publications
Kempski, J., Giannou, A.D., Riecken, K., Zhao, L., Steglich, B., Lücke, J., Garcia-Perez, L., Karstens, K.-F., Wöstemeier, A., Nawrocki, M., et al. (2020). Gastroenterology 159, 1417-1430.e3.
Background & Aims
Unregulated activity of interleukin (IL) 22 promotes intestinal tumorigenesis in mice. IL22 binds the antagonist IL22 subunit alpha 2 (IL22RA2, also called IL22BP). We studied whether alterations in IL22BP contribute to colorectal carcinogenesis in humans and mice.
Methods
We obtained tumor and nontumor tissues from patients with colorectal cancer (CRC) and measured levels of cytokines by quantitative polymerase chain reaction, flow cytometry, and immunohistochemistry. We measured levels of Il22bp messenger RNA in colon tissues from wild-type, Tnf–/–, Lta–/–, and Ltb–/– mice. Mice were given azoxymethane and dextran sodium sulfate to induce colitis and associated cancer or intracecal injections of MC38 tumor cells. Some mice were given inhibitors of lymphotoxin beta receptor (LTBR). Intestine tissues were analyzed by single-cell sequencing to identify cell sources of lymphotoxin. We performed immunohistochemistry analysis of colon tissue microarraysfrom patients with CRC (1475 tissue cores, contained tumor and nontumor tissues) and correlated levels of IL22BP with patient survival times.
Results
Levels of IL22BP were decreased in human colorectal tumors, compared with nontumor tissues, and correlated with levels of lymphotoxin. LTBR signaling was required for expression of IL22BP in colon tissues of mice. Wild-type mice given LTBR inhibitors had an increased tumor burden in both models, but LTBR inhibitors did not increase tumor growth in Il22bp–/– mice. Lymphotoxin directly induced expression of IL22BP in cultured human monocyte–derived dendritic cells via activation of nuclear factor κB. Reduced levels of IL22BP in colorectal tumor tissues were associated with shorter survival times of patients with CRC.
Conclusions
Lymphotoxin signaling regulates expression of IL22BP in colon; levels of IL22BP are reduced in human colorectal tumors, associated with shorter survival times. LTBR signaling regulates expression of IL22BP in colon tumors in mice and cultured human dendritic cells. Patients with colorectal tumors that express low levels of IL22BP might benefit from treatment with an IL22 antagonist.
Brockmann, L., Soukou, S., Steglich, B., Czarnewski, P., Zhao, L., Wende, S., Bedke, T., Ergen, C., Manthey, C., Agalioti, T., et al. (2018). Nat Commun 9, 5457.
Abstract
IL-10 is a prototypical anti-inflammatory cytokine, which is fundamental to the maintenance of immune homeostasis, especially in the intestine. There is an assumption that cells producing IL-10 have an immunoregulatory function. However, here we report that IL-10-producing CD4+ T cells are phenotypically and functionally heterogeneous. By combining single cell transcriptome and functional analyses, we identified a subpopulation of IL-10-producing Foxp3neg CD4+ T cells that displays regulatory activity unlike other IL-10-producing CD4+ T cells, which are unexpectedly pro-inflammatory. The combinatorial expression of co-inhibitory receptors is sufficient to discriminate IL-10-producing CD4+ T cells with regulatory function from others and to identify them across different tissues and disease models in mice and humans. These regulatory IL-10-producing Foxp3neg CD4+ T cells have a unique transcriptional program, which goes beyond the regulation of IL-10 expression. Finally, we found that patients with Inflammatory Bowel Disease demonstrate a deficiency in this specific regulatory T-cell subpopulation.
5. Pelczar, P., Witkowski, M., Perez, L.G., Kempski, J., Hammel, A.G., Brockmann, L., Kleinschmidt, D., Wende, S., Haueis, C., Bedke, T., et al. (2016). Science 354, 6.
Abstract
Intestinal inflammation can impair mucosal healing, thereby establishing a vicious cycle leading to chronic inflammatory bowel disease (IBD). However, the signaling networks driving chronic inflammation remain unclear. Here we report that CD4+ T cells isolated from patients with IBD produce high levels of interleukin-22 binding protein (IL-22BP), the endogenous inhibitor of the tissue-protective cytokine IL-22. Using mouse models, we demonstrate that IBD development requires T cell-derived IL-22BP. Lastly, intestinal CD4+ T cells isolated from IBD patients responsive to treatment with antibodies against tumor necrosis factor-α (anti-TNF-α), the most effective known IBD therapy, exhibited reduced amounts of IL-22BP expression but still expressed IL-22. Our findings suggest that anti-TNF-α therapy may act at least in part by suppressing IL-22BP and point toward a more specific potential therapy for IBD.
Team
Prof. Dr. med. Samuel Huber
Head Huber Lab
Clinic Director
Head of Molecular Gastroenterology and Immunology
E-mail address:
Team Huber Lab
Tanja Bedke, Postdoc
Franziska Bertram, Clinician Scientist
Tom Blankenburg, Technician
Marius Böttcher, Clinician Scientist
Sogol Dostiar Tabrizi, PhD student
Gemma Douilhet, Postdoc
Can Ergen-Behr, Clinician Scientist
Anastasios Giannou, Postdoc
Cathleen Haueis, Technician
Saskia Großhauser, Technician
Jan Kempski, Clinician Scientist
Philine Letz, PhD student
Beibei Liu, PhD student
Jöran Lücke, Clinician Scientist
Andres Machicote, Postdoc
Mikolaj Nawrocki, Clinician Scientist
Justus Neuendorff, MD student
Eleftherios Papazoglou, PhD student
Penelope Pelczar, Postdoc
Amanda Pidgornij, Technician
Maya Romanskyy, MD student
Babett Steglich, Postdoc
Friederike Stumme, Postdoc
Yunhe Tang, PhD student
Huu Ban Tran, MD student
Lis Velasquez, Postdoc
Sandra Wende, Technician
Siwen Zhang, PhD student