Cholinergic receptor activation on epithelia protects against cytokine‐induced barrier dysfunction. (April 2015)

• Record Type: Journal Article
• Authors: Dhawan, S.; Hiemstra, I. H.; Verseijden, C.; Hilbers, F. W.; te Velde, A. A.; Willemsen, L. E. M.; Stap, J.; den Haan, J. M.; de Jonge, W. J.
• Is Part Of: Acta physiologica. Volume 213:Number 4(2015:Apr.)
• Page Start: 846
• Page End: 859
• Publication Date: 2015-04
• Subjects: Physiology -- Periodicals; Physiology -- Research -- Periodicals; 612
• DOI: 10.1111/apha.12469
• Languages: English
• ISSNs: 1748-1708

Abstract

<abstract abstract-type="main" id="apha12469-abs-0001"> <title>Abstract</title> <sec id="apha12469-sec-0001" sec-type="section"> <title>Aim</title> <p>Various types of cholinergic receptors are expressed on intestinal epithelia. Their function is not completely understood. We hypothesize that cholinergic receptor activation on epithelium may serve a protective function in cytokine‐induced barrier dysfunction.</p> </sec> <sec id="apha12469-sec-0002" sec-type="section"> <title>Methods</title> <p>The effect of cholinergic receptor activation on cellular barrier function in epithelial cells was assessed by measuring electrical impedance, and by determining para‐cellular transport in transwell experiments. Cell lysates treated with cytokine and/or cholinergic agonists were analysed for cyto‐ and chemokine production, and tight junction (TJ) protein rearrangement was assessed. Primary colonic epithelial cells were isolated from surgically resected colon tissue of patients with inflammatory bowel disease.</p> </sec> <sec id="apha12469-sec-0003" sec-type="section"> <title>Results</title> <p>IL‐1<italic>β</italic> induced production of chemokines (CXCL‐1, CXCL‐10, IL‐8, CCL‐7) and led to a rearrangement of TJ proteins (occludin and ZO‐1). This response was inhibited by pre‐treatment with muscarinic, rather than nicotinic, acetylcholine receptor agonists. Treatment with IL‐1<italic>β</italic> enhanced paracellular permeability (4kD dextran) and reduced impedance across the monolayer, which was counteracted by pre‐incubation with acetylcholine, or muscarinic receptor agonist bethanechol. The protective effect of acetylcholine was antagonized by atropine, underscoring muscarinic receptor involvement. IL‐1<italic>β</italic> induced transcription of myosin light chain kinase and phosphorylation of myosin light chain, and this cytokine‐induced phosphorylation of MLC was inhibited by muscarinic receptor agonists. Furthermore, in epithelial cells from resection material of patients with Crohn's disease and ulcerative colitis, high expression of <italic>CXCL‐8</italic> was associated with a reduced <italic>choline acetyl transferase</italic> expression, suggesting an aberrant epithelial production of ACh in inflammatory context.</p> </sec> <sec id="apha12469-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Acetylcholine acts on muscarinic receptors on epithelial cells to maintain epithelial barrier function under inflammatory conditions.</p> </sec> </abstract>