Kidd M, Gustafsson B I, Drozdov I, Modlin I M
Department of Surgery, Yale University School of Medicine, New Haven, CT 06520, USA.
Neurogastroenterol Motil. 2009 Apr;21(4):439-50. doi: 10.1111/j.1365-2982.2008.01210.x. Epub 2008 Oct 25.
Gut mucosal enterochromaffin (EC) cells are regarded as key regulators of intestinal motility and fluid secretion via secretion of serotonin (5HT), are increased in numbers in mucosal inflammation and located in close proximity to immune cells. We examined whether interleukin (IL)1beta and Escherichia coli lipopolysaccharide (LPS) induced EC cell 5HT release through Toll-like/IL-1 (TIL) receptor activation, nuclear factor kappa B (NFkappaB) and mitogen-activated protein kinase (MAPK) phosphorylation and evaluated whether somatostatin could inhibit this phenomenon. Pure (>98%) human intestinal EC cells were isolated by fluorescent activated cell sorting from preparations of normal (n = 5) and Crohn's colitis (n = 6) mucosa. 5HT release was measured (ELISA), and NFkappaB and ERK phosphorylation quantitated (ELISA) in response to IL1beta and LPS. 5HT secretion was increased by both E. coli LPS (EC(50) = 5 ng mL(-1)) and IL1beta (EC(50) = 0.05 pmol L(-1)) >2-fold (P < 0.05) in Crohn's EC cells compared with normal EC cells. Secretion was reversible by the TLR4 antagonist, E. coli K12 LPS (IC(50) = 12 ng mL(-1)) and the IL1beta receptor antagonist (ILRA; IC(50) = 3.4 ng mL(-1)). IL1beta caused significant (P < 0.05) NFkappaB and MAPK phosphorylation (40-55%). The somatostatin analogue, lanreotide inhibited IL1beta-stimulated secretion in Crohn's (IC(50) = 0.61 nmol L(-1)) and normal EC cells (IC(50) = 1.8 nmol L(-1)). Interleukins (IL1beta) and bacterial products (E. coli LPS) stimulated 5HT secretion from Crohn's EC cells via TIL receptor activation (TLR4 and IL1beta). Immune-mediated alterations in EC cell secretion of 5HT may represent a component of the pathogenesis of abnormal bowel function in Crohn's disease. Inhibition of EC cell-mediated 5HT secretion may be an alternative therapeutic strategy in the amelioration of inflammatory bowel disease symptomatology.
肠道黏膜肠嗜铬（EC）细胞被视为通过分泌5-羟色胺（5HT）来调节肠道蠕动和液体分泌的关键调节因子，其数量在黏膜炎症时会增加，且位于免疫细胞附近。我们研究了白细胞介素（IL）-1β和大肠杆菌脂多糖（LPS）是否通过Toll样/IL-1（TIL）受体激活、核因子κB（NFκB）和丝裂原活化蛋白激酶（MAPK）磷酸化来诱导EC细胞释放5HT，并评估了生长抑素是否能抑制这一现象。通过荧光激活细胞分选从正常（n = 5）和克罗恩病结肠炎（n = 6）黏膜制备物中分离出纯度>98%的人肠道EC细胞。测量5HT释放（ELISA法），并对IL-1β和LPS刺激下的NFκB和ERK磷酸化进行定量（ELISA法）。与正常EC细胞相比，大肠杆菌LPS（EC50 = 5 ng/mL）和IL-1β（EC50 = 0.05 pmol/L）均可使克罗恩病EC细胞的5HT分泌增加2倍以上（P < 0.05）。TLR4拮抗剂大肠杆菌K12 LPS（IC50 = 12 ng/mL）和IL-1β受体拮抗剂（ILRA；IC50 = 3.4 ng/mL）可使分泌逆转。IL-1β可导致显著的（P < 0.05）NFκB和MAPK磷酸化（40 - 55%）。生长抑素类似物兰瑞肽可抑制克罗恩病（IC50 = 0.61 nmol/L）和正常EC细胞（IC50 = 1.8 nmol/L）中IL-1β刺激的分泌。白细胞介素（IL-1β）和细菌产物（大肠杆菌LPS）通过TIL受体激活（TLR4和IL-1β）刺激克罗恩病EC细胞分泌5HT。免疫介导的EC细胞5HT分泌改变可能是克罗恩病肠道功能异常发病机制的一个组成部分。抑制EC细胞介导的5HT分泌可能是改善炎症性肠病症状的一种替代治疗策略。
