AMP-18 protects barrier function of colonic epithelial cells: role of tight junction proteins
AMP-18 protects barrier function of colonic epithelial cells: role of tight junction proteins
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DOI：
10.1152/ajpgi.00013.2005
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发表时间：
2005-07-01
影响因子：
4.5
通讯作者：
Toback, FG
中科院分区：
文献类型：
--
作者：
Walsh-Reitz, MM;Huang, EF;Toback, FG
胃窦粘膜蛋白(AMP)-18和氨基酸合成肽77-97对上皮细胞具有有丝分裂和运动特性。在小鼠结肠黏膜和人结肠上皮Caco-2/bbe （C2）细胞的单层培养中，AMP-18也可能具有保护作用。给予葡聚糖硫酸钠（DSS）诱导的结肠损伤小鼠AMP肽可以延缓出血性腹泻的发生，减轻体重。用AMP肽保护单层处理C2细胞，防止氧化剂单氯胺、吲哚美辛或DSS诱导的上皮电阻下降。通过询问AMP肽是否作用于特定的紧密连接（TJ）蛋白，寻求这些屏障保护作用的分子机制。用AMP肽处理的C2细胞的洗涤剂不溶性部分的免疫印迹显示特异性TJ蛋白的积累增加。从注射AMP肽的小鼠结肠粘膜细胞中获得的洗涤剂不溶性组分的Occludin免疫反应性也增加。激光扫描共聚焦（CF）显微镜观察证实了AMP肽增强C2细胞单层TJ结构域occludin和zonula occluden -1积累的能力，并结合免疫印迹分析表明，AMP肽可以防止氧化损伤后这些TJ蛋白的丢失。当细胞松弛素D破坏肌动蛋白丝时，AMP肽还可以防止TER下降，并在氧化损伤时稳定周结肌动蛋白。这些发现表明AMP-18可以通过作用于特定的TJ蛋白和稳定周结肌动蛋白来保护肠粘膜屏障。
Antrum mucosal protein ( AMP)-18 and a synthetic peptide of amino acids 77-97 have mitogenic and motogenic properties for epithelial cells. The possibility that AMP-18 is also protective was evaluated in the colonic mucosa of mice and monolayer cultures of human colonic epithelial Caco-2/bbe (C2) cells. Administration of AMP peptide to mice with dextran sulfate sodium (DSS)-induced colonic injury delayed the onset of bloody diarrhea and reduced weight loss. Treatment of C2 cells with AMP peptide protected monolayers against decreases in transepithelial electrical resistance induced by the oxidant monochloramine, indomethacin, or DSS. A molecular mechanism for these barrier-protective effects was sought by asking whether AMP peptide acted on specific tight junction ( TJ) proteins. Immunoblots of detergent-insoluble fractions of C2 cells treated with AMP peptide exhibited increased accumulation of specific TJ proteins. Occludin immunoreactivity was also increased in detergent-insoluble fractions obtained from colonic mucosal cells of mice injected with AMP peptide. Observations using laser scanning confocal (CF) microscopy supported the capacity of AMP peptide to enhance accumulation of occludin and zonula occludens-1 in TJ domains of C2 cell monolayers and together with immunoblot analysis showed that the peptide protected against loss of these TJ proteins following oxidant injury. AMP peptide also protected against a fall in TER during disruption of actin filaments by cytochalasin D and stabilized perijunctional actin during oxidant injury when assessed by CF. These findings suggest that AMP-18 could protect the intestinal mucosal barrier by acting on specific TJ proteins and stabilizing perijunctional actin.