cAMP-dependent mobilization of intracellular Ca2+ stores by activation of ryanodine receptors in pancreatic β-cells -: A Ca2+ signaling system stimulated by the insulinotropic hormone glucagon-like peptide-1-(7-37)
cAMP-dependent mobilization of intracellular Ca2+ stores by activation of ryanodine receptors in pancreatic β-cells -: A Ca2+ signaling system stimulated by the insulinotropic hormone glucagon-like peptide-1-(7-37)
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DOI：
10.1074/jbc.274.20.14147
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发表时间：
1999-05-14
影响因子：
4.8
通讯作者：
Habener, JF
中科院分区：
文献类型：
--
作者：
Holz, GG;Leech, CA;Habener, JF
胰高血糖素样肽-1（GLP-1）是一种胰源性促胰岛素激素，目前正在研究用作治疗2型糖尿病的新型治疗药物。胰岛的体外研究表明，GLP-1与特异性β细胞G蛋白偶联受体相互作用，从而通过提高细胞内cAMP和Ca 2+水平促进胰岛素胞吐作用。在这里，我们报告GLP-1对Ca 2+信号传导的刺激影响，部分来自cAMP依赖性动员的ryanodine敏感的Ca 2+商店。对人类、大鼠和小鼠β细胞的研究表明，兰尼碱的荧光衍生物（BODIPY FL-X兰尼碱）与其受体的结合具有特异性、可逆性和高亲和力。通过逆转录酶聚合酶链反应分析显示大鼠胰岛和BTC 3胰岛素瘤细胞表达对应于兰尼定受体-细胞内Ca 2+释放通道（RYR 2）的2型同种型的mRNA。使用大鼠和人β细胞的原代培养物的[Ca 2 +]（i）的单细胞测量表明GLP-1促进Ca 2+诱导的Ca 2+释放（CICR），其中Ca 2+通过L-型Ca 2+通道流入触发Ca 2+库的动员。在这些细胞中，GLP-1显示与D-葡萄糖代谢相互作用，产生[Ca 2 +]的快速瞬时增加（i）。这种作用可被8-Br-cAMP复制，但可被GLP-1受体拮抗剂阻断（exendin-（9-39）），cAMP拮抗剂（（Rp）-cAMPS），L型Ca 2+通道拮抗剂（尼莫地平），肌浆网Ca 2 + ATP酶拮抗剂通过电压钳分析表征CICR机制也证明了咖啡因对Ca 2+释放的刺激。这些发现为β细胞信号转导模型提供了新的支持，其中GLP-1通过使细胞内Ca 2+释放通道对细胞溶质Ca 2+的刺激影响敏感来促进CICR。
Glucagon-like peptide-1 (GLP-1) is an intestinally derived insulinotropic hormone currently under investigation for use as a novel therapeutic agent in the treatment of type 2 diabetes mellitus, In vitro studies of pancreatic islets of Langerhans demonstrated that GLP-1 interacts with specific beta-cell G protein-coupled receptors, thereby facilitating insulin exocytosis by raising intracellular levels of cAMP and Ca2+. Here we report that the stimulatory influence of GLP-1 on Ca2+ signaling results, in part, from cAMP-dependent mobilization of ryanodine-sensitive Ca2+ stores. Studies of human, rat, and mouse beta-cells demonstrate that the binding of a fluorescent derivative of ryanodine (BODIPY FL-X ryanodine) to its receptors is specific, reversible, and of high affinity. Rat islets and BTC3 insulinoma cells are shown by reverse transcriptase polymerase chain reaction analyses to express mRNA corresponding to the type 2 isoform of ryanodine receptor-intracellular Ca2+ release channel (RYR2), Single-cell measurements of [Ca2+](i) using primary cultures of rat and human beta-cells indicate that GLP-1 facilitates Ca2+-induced Ca2+ release (CICR), whereby mobilization of Ca2+ stores is triggered by influx of Ca2+ through L-type Ca2+ channels, In these cells, GLP-1 is shown to interact with metabolism of D-glucose to produce a fast transient increase of [Ca2+](i). This effect is reproduced by 8-Br-cAMP, but is blocked by a GLP-1 receptor antagonist (exendin-(9-39)), a cAMP antagonist ((Rp)-cAMPS), an L-type Ca2+ channel antagonist (nimodipine), an antagonist of the sarco(endo)plasmic reticulum Ca2+ ATPase (thapsigargin), or by ryanodine, Characterization of the CICR mechanism by voltage clamp analysis also demonstrates a stimulation of Ca2+ release by caffeine. These findings provide new support for a model of beta-cell signal transduction whereby GLP-1 promotes CICR by sensitizing intracellular Ca2+ release channels to the stimulatory influence of cytosolic Ca2+.