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Bonifacio E.,TU Dresden | Bonifacio E.,Paul Langerhans Institute Dresden | Krumsiek J.,Helmholtz Center Munich | Winkler C.,Forschergruppe Diabetes e.V. | And 5 more authors.
Acta Diabetologica | Year: 2014

We recently developed a novel approach capable of identifying gene combinations to obtain maximal disease risk stratification. Type 1 diabetes has a pre-clinical phase including seroconversion to autoimmunity and subsequent progression to diabetes. Here, we applied our gene combination approach to identify combinations that contribute either to islet autoimmunity or to the progression from islet autoantibodies to diabetes onset. We examined 12 type 1 diabetes susceptibility genes (INS, ERBB3, PTPN2, IFIH1, PTPN22, KIAA0350, CD25, CTLA4, SH2B3, IL2, IL18RAP, IL10) in a cohort of children of parents with type 1 diabetes and prospectively followed from birth. The most predictive combination was subsequently applied to a smaller validation cohort. The combinations of genes only marginally contributed to the risk of developing islet autoimmunity, but could substantially modify risk of progression to diabetes in islet autoantibody-positive children. The greatest discrimination was provided by risk allele scores of five genes, INS, IFIH1, IL18RAP, CD25, and IL2 genes, which could identify 80% of islet autoantibody-positive children who progressed to diabetes within 6 years of seroconversion and discriminate high risk (63% within 6 years; 95% CI 45-81%) and low risk (11% within 6 years; 95% CI 0.1-22%; p = 4 × 10-5) antibody-positive children. Risk stratification by these five genes was confirmed in a second cohort of islet autoantibody children. These findings highlight genes that may affect the rate of the beta-cell destruction process once autoimmunity has initiated and may help to identify islet autoantibody-positive subjects with rapid progression to diabetes. © Springer-Verlag 2013. Source


Samikannu B.,Justus Liebig University | Chen C.,Paul Langerhans Institute Dresden | Lingwal N.,Justus Liebig University | Padmasekar M.,Justus Liebig University | And 2 more authors.
PLoS ONE | Year: 2013

Substitution of pancreatic islets is a potential therapy to treat diabetes and it depends on reconstitution of islet's capillary network. In this study, we addressed the question whether stabilization of Glucagon-Like-Peptide-1 (GLP-1) by inhibiting Dipeptidyl Peptidase-IV (DPP-IV) increases β-cell mass by modulating vascularization. Mouse or porcine donor islets were implanted under kidney capsule of diabetic mice treated with DPP-IV inhibitor sitagliptin. Grafts were analyzed for insulin production, β-cell proliferation and vascularization. In addition, the effect of sitagliptin on sprouting and Vascular Endothelial Growth Factor (VEGF)-A expression was examined ex vivo. The cAMP response element-binding (CREB) and VEGF-A/Vascular Endothelial Growth Factor Receptor (VEGFR)-2 signaling pathway leading to islet vascularization was explored. Sitagliptin increased mean insulin content of islet grafts and area of insulin-positive tissue as well as β-cell proliferation. Interestingly, sitagliptin treatment also markedly increased endothelial cell proliferation, microvessel density and blood flow. Finally, GLP-1 (7-36) stimulated sprouting and VEGF expression, which was significantly enhanced by sitagliptin- mediated inhibition of DPP-IV. Our in vivo data demonstrate that sitagliptin treatment phosphorylated CREB and induced islet vascularization through VEGF-A/VEGFR-2 signaling pathway. This study paves a new pathway for improvement of islet transplantation in treating diabetes mellitus. © 2013 Samikannu et al. Source


Phieler J.,TU Dresden | Garcia-Martin R.,TU Dresden | Lambris J.D.,University of Pennsylvania | Chavakis T.,TU Dresden | Chavakis T.,Paul Langerhans Institute Dresden
Seminars in Immunology | Year: 2013

Emerging evidence points to a close crosstalk between metabolic organs and innate immunity in the course of metabolic disorders. In particular, cellular and humoral factors of innate immunity are thought to contribute to metabolic dysregulation of the adipose tissue or the liver, as well as to dysfunction of the pancreas; all these conditions are linked to the development of insulin resistance and diabetes mellitus. A central component of innate immunity is the complement system. Interestingly, the classical view of complement as a major system of host defense that copes with infections is changing to that of a multi-functional player in tissue homeostasis, degeneration, and regeneration. In the present review, we will discuss the link between complement and metabolic organs, focusing on the pancreas, adipose tissue, and liver and the diverse effects of complement system on metabolic disorders. © 2013 Elsevier Ltd. Source


Spiering R.,University Utrecht | Margry B.,University Utrecht | Keijzer C.,University Utrecht | Petzold C.,Foundation University | And 7 more authors.
Journal of Immunology | Year: 2015

Previous studies in mouse models of autoimmune diabetes and encephalomyelitis have indicated that the selective delivery of self-antigen to the endocytic receptor DEC205 on steady-state dendritic cells (DCs) may represent a suitable approach to induce Ag-specific immune tolerance. In this study, we aimed to examine whether DEC205+ DC targeting of a single immunodominant peptide derived from human cartilage proteoglycan (PG) can promote immune tolerance in PG-induced arthritis (PGIA). Besides disease induction by immunization with whole PG protein with a high degree of antigenic complexity, PGIA substantially differs from previously studied autoimmune models not only in the target tissue of autoimmune destruction but also in the nature of pathogenic immune effector cells. Our results show that DEC205+ DC targeting of the PG peptide 70-84 is sufficient to efficiently protect against PGIA development. Complementary mechanistic studies support a model in which DEC205+ DC targeting leads to insufficient germinal center B cell support by PG-specific follicular helper T cells. Consequently, impaired germinal center formation results in lower Ab titers, severely compromising the development of PGIA. Overall, this study further corroborates the potential of prospective tolerogenic DEC205+ DC vaccination to interfere with autoimmune diseases, such as rheumatoid arthritis. Copyright © 2015 by The American Association of Immunologists, Inc. Source


Tsuji N.,University of California at San Francisco | Ninov N.,University of California at San Francisco | Ninov N.,Max Planck Institute for Heart and Lung Research | Ninov N.,TU Dresden | And 7 more authors.
PLoS ONE | Year: 2014

Inducing beta-cell mass expansion in diabetic patients with the aim to restore glucose homeostasis is a promising therapeutic strategy. Although several in vitro studies have been carried out to identify modulators of beta-cell mass expansion, restoring endogenous beta-cell mass in vivo has yet to be achieved. To identify potential stimulators of beta-cell replication in vivo, we established transgenic zebrafish lines that monitor and allow the quantification of cell proliferation by using the fluorescent ubiquitylation-based cell cycle indicator (FUCCI) technology. Using these new reagents, we performed an unbiased chemical screen, and identified 20 small molecules that markedly increased beta-cell proliferation in vivo. Importantly, these structurally distinct molecules, which include clinically-approved drugs, modulate three specific signaling pathways: serotonin, retinoic acid and glucocorticoids, showing the high sensitivity and robustness of our screen. Notably, two drug classes, retinoic acid and glucocorticoids, also promoted beta-cell regeneration after beta-cell ablation. Thus, this study establishes a proof of principle for a high-throughput small molecule-screen for beta-cell proliferation in vivo, and identified compounds that stimulate beta-cell proliferation and regeneration. © 2014 Tsuji et al. Source

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