| 1. |
- Muntjewerff, Elke M., et al.
(författare)
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Chromogranin A regulates gut permeability via the antagonistic actions of its proteolytic peptides
- 2021
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Ingår i: Acta Physiologica. - : John Wiley & Sons. - 1748-1708 .- 1748-1716. ; 232:2
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Tidskriftsartikel (refereegranskat)abstract
- Aim A "leaky" gut barrier has been implicated in the initiation and progression of a multitude of diseases, for example, inflammatory bowel disease (IBD), irritable bowel syndrome and celiac disease. Here we show how pro-hormone Chromogranin A (CgA), produced by the enteroendocrine cells, and Catestatin (CST: hCgA(352-372)), the most abundant CgA-derived proteolytic peptide, affect the gut barrier. Methods Colon tissues from region-specific CST-knockout (CST-KO) mice, CgA-knockout (CgA-KO) and WT mice were analysed by immunohistochemistry, western blot, ultrastructural and flowcytometry studies. FITC-dextran assays were used to measure intestinal barrier function. Mice were supplemented with CST or CgA fragment pancreastatin (PST: CgA(250-301)). The microbial composition of cecum was determined. CgA and CST levels were measured in blood of IBD patients. Results Plasma levels of CST were elevated in IBD patients. CST-KO mice displayed (a) elongated tight, adherens junctions and desmosomes similar to IBD patients, (b) elevated expression of Claudin 2, and (c) gut inflammation. Plasma FITC-dextran measurements showed increased intestinal paracellular permeability in the CST-KO mice. This correlated with a higher ratio of Firmicutes to Bacteroidetes, a dysbiotic pattern commonly encountered in various diseases. Supplementation of CST-KO mice with recombinant CST restored paracellular permeability and reversed inflammation, whereas CgA-KO mice supplementation with CST and/or PST in CgA-KO mice showed that intestinal paracellular permeability is regulated by the antagonistic roles of these two peptides: CST reduces and PST increases permeability. Conclusion The pro-hormone CgA regulates the intestinal paracellular permeability. CST is both necessary and sufficient to reduce permeability and primarily acts by antagonizing PST.
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| 2. |
- Muntjewerff, Elke M., et al.
(författare)
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Putative regulation of macrophage-mediated inflammation by catestatin
- 2022
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Ingår i: Trends in immunology. - : Elsevier. - 1471-4906 .- 1471-4981. ; 43:1, s. 41-50
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Forskningsöversikt (refereegranskat)abstract
- Catestatin (CST) is a bioactive cleavage product of the neuroendocrine prohormone chromogranin A (CgA). Recent findings show that CST can exert anti-inflammatory and antiadrenergic effects by suppressing the inflammatory actions of mammalian macrophages. However, recent findings also suggest that macrophages themselves are major CST producers. Here, we hypothesize that macrophages produce CST in an inflammation-dependent manner and thereby might self-regulate inflammation in an autocrine fashion. CST is associated with pathological conditions hallmarked by chronic inflammation, including autoimmune, cardiovascular, and metabolic disorders. Since intraperitoneal injection of CST in mouse models of diabetes and inflammatory bowel disease has been reported to be beneficial formitigating disease, we posit that CST should be further investigated as a candidate target for treating certain inflammatory diseases.
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| 3. |
- Muntjewerff, Elke M., et al.
(författare)
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The anti-inflammatory peptide Catestatin blocks chemotaxis
- 2022
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Ingår i: Journal of Leukocyte Biology. - : John Wiley & Sons. - 0741-5400 .- 1938-3673. ; 112:2, s. 273-278
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Tidskriftsartikel (refereegranskat)abstract
- Increased levels of the anti-inflammatory peptide Catestatin (CST), a cleavage product of the pro-hormone chromogranin A, correlate with less severe outcomes in hypertension, colitis, and diabetes. However, it is unknown how CST reduces the infiltration of monocytes and macrophages (M phi s) in inflamed tissues. Here, it is reported that CST blocks leukocyte migration toward inflammatory chemokines. By in vitro and in vivo migration assays, it is shown that although CST itself is chemotactic, it blocks migration of monocytes and neutrophils to inflammatory attracting factor CC-chemokine ligand 2 (CCL2) and C-X-C motif chemokine ligand 2 (CXCL2). Moreover, it directs CX(3)CR1(+) M phi s away from pancreatic islets. These findings suggest that the anti-inflammatory actions of CST are partly caused by its regulation of chemotaxis.
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| 4. |
- Muntjewerff, Elke M., et al.
(författare)
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Three-dimensional Co-culture Model for Live Imaging of Pancreatic Islets, Immune Cells, and Neurons in Agarose Gel
- 2023
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Ingår i: Bio-protocol. - : Bio-Protocol LLC. - 2331-8325. ; 13:20
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Tidskriftsartikel (refereegranskat)abstract
- During the onset of autoimmune diabetes, nerve-immune cell interactions seem to play an important role; however, there are currently no models to follow and interfere with these interactions over time in vivo or in vitro. Twodimensional in vitro models provide insufficient information and microfluidics or organs on a chip are usually challenging to work with. We present here what we believe to be the first simple model that provides the opportunity to co-culture pancreatic islets with sympathetic nerves and immune cells. This model is based on our stamping device that can be 3D printed (STL file provided). Due to the imprint in the agarose gel, sympathetic neurons, pancreatic islets, and macrophages can be seeded in specific locations at a level that allows for confocal live-cell imaging. In this protocol, we provide the instructions to construct and perform live cell imaging experiments in our co-culture model, including: 1) design for the stamping device to make the imprint in the gel, 2) isolation of sympathetic neurons, pancreatic islets, and macrophages, 3) co-culture conditions, 4) how this can be used for live cell imaging, and 5) possibilities for wider use of the model. In summary, we developed an easy-to-use co-culture model that allows manipulation and imaging of interactions between sympathetic nerves, pancreatic islets, and macrophages. This new co-culture model is useful to study nerve-immune cell-islet interactions and will help to identify the functional relevance of neuro-immune interactions in the pancreas.
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