Effect of n-3 polyunsaturated fatty acids on membrane microdomain localization of tight junction proteins in experimental colitis.
Ulcerative colitis (UC) is a gastrointestinal disorder characterized by an inflammatory process associated with mucosal damage. Many studies have shown that n-3 polyunsaturated fatty acids (PUFAs) possess anti-inflammatory effects in inflammatory bowel disease. The aim of this study was to investigate whether n-3 PUFAs could alleviate intestinal damage in experimental UC. In the present study, we found that in 2,4,6-trinitrobenzenesulfonic acid-induced colitic rats, the damage to the intestinal mucosa was accompanied by a disrupted tight junction (TJ) structure. In accordance with these changes, the distribution and expression of TJ proteins, including occludin, claudin-1, claudin-3, claudin-5, claudin-8 and ZO-1, in membrane microdomains was altered. The distribution of flotillin-1, a lipid raft marker protein, was also changed. Moreover, we found for the first time that n-3 PUFAs prevented redistribution of TJ proteins from Triton X-100-insoluble raft-like membrane microdomains to Triton X-100-soluble fractions. The expression of ZO-1, claudin-1, claudin-5 and claudin-8 was significantly elevated by n-3 PUFAs. n-3 PUFAs also attenuated the disruption of TJ structure and improved the histological score. Our results demonstrate that the expression and distribution of TJ proteins in TJ membrane microdomains might be affected in UC, and that such altered expression of TJ proteins in membrane microdomains in experimental UC is affected by n-3 PUFAs. These findings may have therapeutic potential in intestinal inflammation.
Li
Qiurong
Q
Institute of General Surgery, Jinling Hospital, Nanjing, China. liqiurong@yahoo.com
Zhang
Qiang
Q
Zhang
Min
M
Wang
Chenyang
C
Zhu
Zhenxin
Z
Li
Ning
N
Li
Jieshou
J
D000818:Animals; D015153:Blotting, Western; D062445:Claudin-1; D003092:Colitis / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D003106:Colon / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D021962:Membrane Microdomains / Q000187:drug effects* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D062793:Occludin; D010750:Phosphoproteins / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D014302:Trinitrobenzenesulfonic Acid; D062826:Zonula Occludens-1 Protein
D062445:Claudin-1; C568114:Cldn1 protein, rat; D008565:Membrane Proteins; D062793:Occludin; C568987:Ocln protein, rat; D010750:Phosphoproteins; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; D014302:Trinitrobenzenesulfonic Acid