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GRK 1482 Jahrbuch 2011-2014

Publications [1] Schäffler A, Schölmerich J, Büchler C. Mechanism of di- sease: adipocytokines and visceral adipose tissue - emerging role in intestinal and mesenteric disease. Nat Clin Pract Gastroenterol & Hepatol. 2005; 2(2):103-111. [2] Cromer WE, Mathis JM, Granger DN, Chaitanya GV, Alex- ander JS. Role of the endothelium in inflammatory bowel diseases. World J Gastroenterol. 2011; 17(5): 578-593. [3] Arrieta MC, Bistritz L, Meddings JB. Alterations in intesti- nal permeability. Gut. 2006; 55(10):1512-20. [4] Hossain Z, Hirata T. Molecular mechanism of intestinal permeability: interaction at tight junctions. Mol Biosyst. 2008; 4(12):1181-1185. [5] Ludwig T, Worsch S, Heikenwalder M, Daniel H, Hauner H, Bader BL. Metabolic and immunomodulatory effects of n-3 fatty acids are different in mesenteric and epididy- mal adipose tissue of diet-induced obese mice. Am J Physiol Endocrinol Metab. 2013 Mar 12. [Epub ahead of print]. Outlook To determine the physiological impact of different high-fat diets and fatty acids on intestinal barriers and vascular functions in mice, the analysis of vascular permeability by tail vein injections of Evans blue and/or FITC-dextran and vascular tone measu- rements of mesenteric vessels are of importance. Cell culture experiments will be necessary for mechanistic studies. ASSOCIATED FELLOWS GRK Progress Report 2011-2014 | Page 79 Aim Considering the link of visceral obesity to inflammatory bo- wel diseases and vascular dysfunction, we aim to explore the molecular and physiological effects of different high-fat diets and fatty acids on the small intestine and adjacent mesenteric adipose tissue compared to control diet. The morphology and permeability of the epithelium and vasculature in the small in- testine and adjacent mesenteric vasculature, as well as associ- ated cell biological, inflammatory and signaling processes will be analyzed. Methods and Results Currently, we pursue our findings from our DIO mouse study of the previous GRK-PhD15/1 project [5] on endothelial cell activation and inflammatory processes in the small intestine and mesenteric adipose tissue (MAT) in obese and control mice. C57BL/6J mice at the age of 8 wk were assigned to 3 dietary groups and fed 3 different diets with varying fat content [control diet (C): 13%; HF: 48% kJ; HF/n-3 (HF enriched with n-3 LC-PUFAs DHA and EPA): 48% kJ] for 6 and 12 weeks. Our current analysis of pathway-specific RT2 Profiler™ RT-qPCR arrays for ‘endothelial cell biology’ (84 target genes) displayed that a significant fraction of genes in the small intestine were upregulated by both high-fat diets compared to controls. These genes are associated with permissibility/vascular tone, angio- genesis and cell adhesion processes. Some of the HF-induced genes were downregulated upon HF/n-3 diet, e.g. mRNA ex- pression for Icam1, Vcam1, and Tek. The genes for eNos and iNos are highly up- or down-regulated, respectively, upon HF and HF/n-3. In order to control NO bioavailability these genes are strictly controlled. iNos is expressed by macrophages in response to inflammatory mediators. Since deregulations of iNOS and eNOS are associated with immune cell-media- ted inflammatory processes and vascular dysfunction and changes of permeability, respectively, we are currently analyzing eNOS and iNOS regarding their expression, activation state and their regulation in the intestine by Western blot, immuno- precipitation (IP) experiments and Co-IP; similarly in MAT. To assess the inflammatory status of the small intestine, cytokine expression and the presence of immune cells like T-cells, macrophages (M1: proinflammatory; M2: anti-inflam- matory) will be examined by RT-qPCR and on protein level. Mor- phological changes of the intestine due to the different high-fat diets will be investigated by immunohistochemistry and immu- nofluorescence microscopy (see figure). Figure: Immunofluorescence microscopy of the mouse small intestine. Intestinal vasculature and epithelial cell layer of the villus region are de- tected by antibodies recognizing endothelial cell marker CD31 (red) and epithelial marker E-cadherin (green), respectively. Cell nuclei are stained by DAPI (blue). 60x magnification. Supervisors Prof. Dr. Hans Hauner | TUM | Nutritional Medicine Dr. Bernhard L. Bader | TUM | Nutritional Medicine Prof. Dr. Hannelore Daniel | TUM | Physiology of Human Nutrition Start of project: September 2011 Academic background: Studies of Molecular Sciences at Friedrich-Alexander Universität Erlangen-Nürnberg