1,25-Dihydroxyvitamin D Protects Intestinal Epithelial Barrier by Regulating the Myosin Light Chain Kinase Signaling Pathway.
1,25-Dihydroxyvitamin D Protects Intestinal Epithelial Barrier by Regulating the Myosin Light Chain Kinase Signaling Pathway.
复制标题
DOI：
10.1097/mib.0000000000000526
复制
发表时间：
2015-11
影响因子：
4.9
通讯作者：
Li YC
中科院分区：
文献类型：
--
作者：
Du J;Chen Y;Shi Y;Liu T;Cao Y;Tang Y;Ge X;Nie H;Zheng C;Li YC
肌球蛋白轻链激酶（MLCK）途径通过调节紧密连接来控制肠上皮屏障通透性。1，25-二羟维生素D（1，25（OH）2D 3）-维生素D受体（VDR）信号转导可保护上皮屏障，但其分子机制尚不完全清楚。使用TNF-α ± 1，25（OH）2D 3处理的HCT 116、Caco-2和SW 480细胞单层研究MLCK活化和屏障渗透性。MLCK通路在溃疡性结肠炎患者的正常和发炎结肠活检中进行了分析。还在维生素D类似物帕立骨化醇处理的野生型小鼠和结肠上皮细胞中携带VDR缺失的小鼠中使用TNBS诱导的结肠炎模型研究了结肠粘膜屏障通透性和MLCK活化。TNF-α可增加细胞单层通透性，诱导MLCK长亚型表达和肌球蛋白II调节轻链（MLC）磷酸化，1，25（OH）2D 3可通过VDR依赖性方式阻断TNF-α诱导的单层通透性增加和MLCK-MLC通路激活。1，25（OH）2D 3通过减弱NF-κB的活化直接抑制长MLCK的表达，ChIP实验证实1，25（OH）2D 3破坏了p65与长MLCK基因启动子中3个κB位点的结合。在人类溃疡性结肠炎活检中，VDR减少与长MLCK表达和MLC磷酸化增加相关。在TNBS结肠炎模型中，帕立骨化醇改善了结肠炎，减弱了粘膜屏障通透性的增加，并抑制了长MLCK诱导和MLC磷酸化。相比之下，结肠上皮VDR缺失的小鼠与野生型小鼠相比，在粘膜屏障通透性和MLCK激活方面表现出更稳健的增加。这些数据表明，1，25（OH）2D 3-VDR信号通过消除结肠炎症期间MLCK依赖性紧密连接失调来保持粘膜屏障完整性。
The myosin light chain kinase (MLCK) pathway controls intestinal epithelial barrier permeability by regulating the tight junction. 1,25-dihydroxyvitamin D (1,25(OH)2D3)-vitamin D receptor (VDR) signaling protects the epithelial barrier, but the molecular mechanism is incompletely understood. MLCK activation and barrier permeability were studied using monolayers of HCT116, Caco-2 and SW480 cells treated with TNF-α ±1,25(OH)2D3. The MLCK pathway was analyzed in normal and inflamed colonic biopsies from ulcerative colitis patients. Colonic mucosal barrier permeability and MLCK activation were also investigated using TNBS-induced colitis models in vitamin D analog paricalcitol-treated wild-type mice and mice carrying VDR deletion in colonic epithelial cells. TNF-α increased cell monolayer permeability and induced long isoform of MLCK expression and myosin II regulatory light chain (MLC) phosphorylation, and 1,25(OH)2D3 blocked TNF-α-induced increases in monolayer permeability and MLCK-MLC pathway activation by a VDR-dependent fashion. 1,25(OH)2D3 directly suppressed long MLCK expression by attenuating NF-κB activation, and ChIP assays confirmed that 1,25(OH)2D3 disrupted p65 binding to three κB sites in long MLCK gene promoter. In human ulcerative colitis biopsies VDR reduction was associated with increases in long MLCK expression and MLC phosphorylation. In TNBS colitis models, paricalcitol ameliorated colitis, attenuated the increase in mucosal barrier permeability and inhibited long MLCK induction and MLC phosphorylation. In contrast, mice with colonic epithelial VDR deletion exhibited more robust increases in mucosal barrier permeability and MLCK activation compared with wild-type mice. These data demonstrate that 1,25(OH)2D3-VDR signaling preserves the mucosal barrier integrity by abrogating MLCK-dependent tight junction dysregulation during colonic inflammation.