Scaldaferri Franco, Sans Miquel, Vetrano Stefania, Correale Carmen, Arena Vincenzo, Pagano Nico, Rando Giacomo, Romeo Fabio, Potenza Angelo E, Repici Alessandro, Malesci Alberto, Danese Silvio
Istituto Clinico Humanitas-IRCCS in Gastroenterology, University of Milan, Rozzano, Milan.
Eur J Immunol. 2009 Jan;39(1):290-300. doi: 10.1002/eji.200838316.
Lymphocyte recruitment is a key pathogenic event in inflammatory bowel disease (IBD). Adhesion of T cells to human intestinal microvascular endothelial cells (HIMEC) is mediated by ICAM-1, VCAM-1 and fractalkine (FKN), but the signaling molecules that orchestrate this process have yet to be identified. Because MAPK play an important role in the response of many cell types to pro-inflammatory stimuli, we assessed the functional role of p38 MAPK, p42/44 MAPK and JNK in the regulation of lymphocyte adhesion to and chemotaxis across the microvasculature in IBD. We found that the MAPK were phosphorylated in the bowel microvasculature and human intestinal fibroblasts of patients with IBD but not of healthy individuals. Stimulation of HIMEC with TNF-alpha triggered phosphorylation of the MAPK, and up-regulation of VCAM-1, FKN and ICAM-1. Blockade of p38 decreased the expression of all MAPK by 50% (p<0.01), whereas inhibition of p42/44 decreased the expression of ICAM-1 and FKN by 50% (p<0.01). Treatment of human intestinal fibroblasts with TNF-alpha elicited production of IL-8 and MCP-1, which was reduced (p<0.05) by blockade of p38 and p42/44. Finally, blockade of p38 and p42/44 reduced lymphocyte adhesion to (p<0.05) and transmigration across (p<0.05) HIMEC monolayers. These findings suggest a critical role for MAPK in governing lymphocyte influx into the gut in IBD patients, and their blockade may offer a molecular target for blockade of leukocyte recruitment to the intestine.
淋巴细胞募集是炎症性肠病（IBD）中的关键致病事件。T细胞与人肠道微血管内皮细胞（HIMEC）的黏附由细胞间黏附分子-1（ICAM-1）、血管细胞黏附分子-1（VCAM-1）和 fractalkine（FKN）介导，但协调这一过程的信号分子尚未确定。由于丝裂原活化蛋白激酶（MAPK）在许多细胞类型对促炎刺激的反应中起重要作用，我们评估了p38 MAPK、p42/44 MAPK和JNK在IBD中淋巴细胞对微血管的黏附和趋化作用调节中的功能作用。我们发现，IBD患者的肠道微血管和人肠道成纤维细胞中的MAPK发生了磷酸化，而健康个体则没有。用肿瘤坏死因子-α（TNF-α）刺激HIMEC会引发MAPK的磷酸化以及VCAM-1、FKN和ICAM-1的上调。阻断p38可使所有MAPK的表达降低50%（p<0.01），而抑制p42/44可使ICAM-1和FKN的表达降低50%（p<0.01）。用TNF-α处理人肠道成纤维细胞会诱导白细胞介素-8（IL-8）和单核细胞趋化蛋白-1（MCP-1）的产生，通过阻断p38和p42/44可使其减少（p<0.05）。最后，阻断p38和p42/44可降低淋巴细胞对HIMEC单层的黏附（p<0.05）和跨膜迁移（p<0.05）。这些发现表明MAPK在IBD患者肠道淋巴细胞流入中起关键作用，阻断它们可能为阻断白细胞募集到肠道提供一个分子靶点。
