Mechanical stimulation activates Gαq signaling pathways and 5-hydroxytryptamine release from human carcinoid BON cells
Mechanical stimulation activates Gαq signaling pathways and 5-hydroxytryptamine release from human carcinoid BON cells
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DOI：
10.1172/jci200112467
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发表时间：
2001-10-01
影响因子：
15.9
通讯作者：
Cooke, HJ
中科院分区：
文献类型：
--
作者：
Kim, M;Javed, NH;Cooke, HJ
5-从肠嗜铬细胞释放的羟色胺（5-HT）激活肠腔内容物的润滑和推进所必需的分泌和蠕动反射。本研究的目的是确定调节S-HT释放的机械敏感性细胞内信号通路。人类癌BON细胞显示5-HT免疫反应性与颗粒分散在整个细胞或在边界。在河豚毒素神经阻滞期间，通过旋转摇动的机械刺激从BON细胞或从豚鼠空肠释放5-HT。在链球菌溶血素O-透化的细胞中，鸟苷5 ' -O-（2-硫代二磷酸）（GDP-P-S）和衍生自G α q的COOH末端的合成肽消除了机械诱发的S-HT释放，而NH 2-末端肽没有。靶向Gaq独特序列的反义硫代磷酸化寡核苷酸消除了机械诱发的5-HT释放，并降低了G α q蛋白水平，而不影响G α的表达（11）。细胞外钙的消耗和螯合作用不引起S-HT释放，而细胞内钙的消耗和1，2-双（邻氨基苯氧基）乙烷-N，N，N '，N'-四乙酸四（乙酰氧基甲基）酯（BAPTA-AM）的螯合作用则减少5-HT释放。生长抑素14以浓度依赖性方式抑制机械诱发的5-HT释放。结果表明，肠嗜铬蛋白衍生的BON细胞的机械刺激直接或间接刺激G蛋白偶联受体，其激活Gaq，动员细胞内钙，并导致S-HT释放。
5-Hydroxytryptamine (5-HT) released from enterochromaffin cells activates secretory and peristaltic reflexes necessary for lubrication and propulsion of intestinal luminal contents. The aim of this study was to identify mechanosensitive intracellular signaling pathways that regulate S-HT release. Human carcinoid BON cells displayed 5-HT immunoreactivity associated with granules dispersed throughout the cells or at the borders. Mechanical stimulation by rotational shaking released 5-HT from BON cells or from guinea pig jejunum during neural blockade with tetrodotoxin. In streptolysin O-permeabilized cells, guanosine 5 ' -O-(2-thiodiphosphate) (GDP-P-S) and a synthetic peptide derived from the COOH terminus of G alphaq abolished mechanically evoked S-HT release, while the NH2-terminal peptide did not. An antisense phosphorothioated oligonucleotide targeted to a unique sequence of Gaq abolished mechanically evoked 5-HT release and reduced G alphaq protein levels without affecting the expression of G alpha (11). Depletion and chelation of extracellular calcium did not after mechanically evoked S-HT release, whereas depletion of intracellular calcium stores by thapsigargin and chelation of intracellular calcium by 1,2-bis (o-Aminophenoxy) ethane-N,N,N',N'-tetraacetic acid tetra (acetoxymethyl) ester (BAPTA-AM) reduced 5-HT release. Mechanically evoked 5-HT release was inhibited by somatostatin-14 in a concentration-dependent manner. The results suggest that mechanical stimulation of enterochromaffin-derived BON cells directly or indirectly stimulates a G protein-coupled receptor that activates Gaq, mobilizes intracellular calcium, and causes S-HT release.