升高的环AMP减少磷酸肌肽的周转和抑制人血小板中凝血酶诱导的分泌

Anita Ryningen, Baard Olav Jensen, Holm Holmsen
{"title":"升高的环AMP减少磷酸肌肽的周转和抑制人血小板中凝血酶诱导的分泌","authors":"Anita Ryningen,&nbsp;Baard Olav Jensen,&nbsp;Holm Holmsen","doi":"10.1016/S0005-2760(98)00106-4","DOIUrl":null,"url":null,"abstract":"<div><p>Elevation of cyclic AMP (cAMP) in platelets inhibits agonist-induced, G protein-mediated responses and activation of polyphosphoinositide-specific phospholipase C (PLC) by ill-defined mechanism(s). Signal transduction steps downstream of PLC are inhibited by elevated cAMP, suggesting an inhibitory effect of cAMP, via protein kinase A, on PLC. In [<sup>32</sup>P]<sub>i</sub>-prelabeled platelets, forskolin increased intracellular cAMP (104 nmol/10<sup>11</sup> cells at 10<sup>−5</sup> M forskolin) and [<sup>32</sup>P]phosphatidylinositol 4-phosphate (Δ[<sup>32</sup>P]PIP) (30% at 10<sup>−7</sup>–10<sup>−6</sup> M forskolin). The thrombin-induced (0.1 U/ml) increase in production of [<sup>32</sup>P]PA, ‘overshoots’ in [<sup>32</sup>P]PIP and [<sup>32</sup>P]PIP<sub>2</sub> ([<sup>32</sup>P]phosphatidylinositol 4,5-bisphosphate), and the increase in [<sup>32</sup>P]PI and secretion of ADP+ATP were abolished by forskolin (10<sup>−7</sup> M). Forskolin stimulated total [<sup>32</sup>P]P<sub>i</sub> uptake in resting platelets (48%), increased <sup>32</sup>P incorporation into PIP (110%), and inhibited <sup>32</sup>P incorporation into PI (50%). The latter inhibition was most likely considerably greater due to the forskolin-induced stimulation of [<sup>32</sup>P]P<sub>i</sub> uptake. The changes in radioactive PA, PIP and PIP<sub>2</sub> are regarded as being proportional with their masses in the prelabeled platelets, while the increase in PI (phosphatidylinositol) is regarded as a change in specific radioactivity, and hence in its synthesis. The results suggest that cAMP elevation inhibits the flux in the polyphosphoinositide cycle through both inhibition of PIP 5-kinase and PI synthesis. The inverse relation between forskolin-produced ΔPIP and [<sup>32</sup>P]PA production suggests that the PLC reaction is inhibited by elevated cAMP through reduction of substrate (PIP<sub>2</sub>) resynthesis, and not by inhibition of the PLC enzyme.</p></div>","PeriodicalId":100162,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism","volume":"1394 2","pages":"Pages 235-248"},"PeriodicalIF":0.0000,"publicationDate":"1998-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0005-2760(98)00106-4","citationCount":"35","resultStr":"{\"title\":\"Elevation of cyclic AMP decreases phosphoinositide turnover and inhibits thrombin-induced secretion in human platelets\",\"authors\":\"Anita Ryningen,&nbsp;Baard Olav Jensen,&nbsp;Holm Holmsen\",\"doi\":\"10.1016/S0005-2760(98)00106-4\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Elevation of cyclic AMP (cAMP) in platelets inhibits agonist-induced, G protein-mediated responses and activation of polyphosphoinositide-specific phospholipase C (PLC) by ill-defined mechanism(s). Signal transduction steps downstream of PLC are inhibited by elevated cAMP, suggesting an inhibitory effect of cAMP, via protein kinase A, on PLC. In [<sup>32</sup>P]<sub>i</sub>-prelabeled platelets, forskolin increased intracellular cAMP (104 nmol/10<sup>11</sup> cells at 10<sup>−5</sup> M forskolin) and [<sup>32</sup>P]phosphatidylinositol 4-phosphate (Δ[<sup>32</sup>P]PIP) (30% at 10<sup>−7</sup>–10<sup>−6</sup> M forskolin). The thrombin-induced (0.1 U/ml) increase in production of [<sup>32</sup>P]PA, ‘overshoots’ in [<sup>32</sup>P]PIP and [<sup>32</sup>P]PIP<sub>2</sub> ([<sup>32</sup>P]phosphatidylinositol 4,5-bisphosphate), and the increase in [<sup>32</sup>P]PI and secretion of ADP+ATP were abolished by forskolin (10<sup>−7</sup> M). Forskolin stimulated total [<sup>32</sup>P]P<sub>i</sub> uptake in resting platelets (48%), increased <sup>32</sup>P incorporation into PIP (110%), and inhibited <sup>32</sup>P incorporation into PI (50%). The latter inhibition was most likely considerably greater due to the forskolin-induced stimulation of [<sup>32</sup>P]P<sub>i</sub> uptake. The changes in radioactive PA, PIP and PIP<sub>2</sub> are regarded as being proportional with their masses in the prelabeled platelets, while the increase in PI (phosphatidylinositol) is regarded as a change in specific radioactivity, and hence in its synthesis. The results suggest that cAMP elevation inhibits the flux in the polyphosphoinositide cycle through both inhibition of PIP 5-kinase and PI synthesis. The inverse relation between forskolin-produced ΔPIP and [<sup>32</sup>P]PA production suggests that the PLC reaction is inhibited by elevated cAMP through reduction of substrate (PIP<sub>2</sub>) resynthesis, and not by inhibition of the PLC enzyme.</p></div>\",\"PeriodicalId\":100162,\"journal\":{\"name\":\"Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism\",\"volume\":\"1394 2\",\"pages\":\"Pages 235-248\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"1998-11-02\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/S0005-2760(98)00106-4\",\"citationCount\":\"35\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0005276098001064\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0005276098001064","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 35

摘要

血小板中环AMP (cAMP)的升高抑制激动剂诱导的、G蛋白介导的反应和多磷肌醇特异性磷脂酶C (PLC)的激活,机制尚不明确。PLC下游的信号转导步骤被升高的cAMP抑制,这表明cAMP通过蛋白激酶A对PLC有抑制作用。在[32P]i预标记的血小板中,forskolin增加了细胞内cAMP(10−5 M forskolin时为104 nmol/1011个细胞)和[32P]磷脂酰肌醇4-磷酸(Δ[32P]PIP)(10−7-10−6 M forskolin时为30%)。凝血酶诱导的[32P]PA的生成增加(0.1 U/ml), [32P]PIP和[32P]PIP2 ([32P]磷脂酰肌醇4,5-二磷酸)的“过量”,[32P]PI的增加和ADP+ATP的分泌被forskolin(10−7 M)所消除。forskolin刺激静息血小板中[32P]PI的总摄取(48%),增加32P并入PIP(110%),抑制32P并入PI(50%)。由于福斯克林诱导的[32P]Pi摄取刺激,后一种抑制很可能要大得多。在预标记的血小板中,放射性PA、PIP和PIP2的变化被认为与它们的质量成正比,而PI(磷脂酰肌醇)的增加被认为是比放射性的变化,从而是其合成的变化。结果表明,cAMP升高通过抑制PIP 5-激酶和PI合成来抑制多磷酸肌醇循环的通量。福斯克林生成ΔPIP与[32P]PA生成之间的反比关系表明,通过减少底物(PIP2)的再合成,升高的cAMP可以抑制PLC反应,而不是通过抑制PLC酶。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Elevation of cyclic AMP decreases phosphoinositide turnover and inhibits thrombin-induced secretion in human platelets

Elevation of cyclic AMP (cAMP) in platelets inhibits agonist-induced, G protein-mediated responses and activation of polyphosphoinositide-specific phospholipase C (PLC) by ill-defined mechanism(s). Signal transduction steps downstream of PLC are inhibited by elevated cAMP, suggesting an inhibitory effect of cAMP, via protein kinase A, on PLC. In [32P]i-prelabeled platelets, forskolin increased intracellular cAMP (104 nmol/1011 cells at 10−5 M forskolin) and [32P]phosphatidylinositol 4-phosphate (Δ[32P]PIP) (30% at 10−7–10−6 M forskolin). The thrombin-induced (0.1 U/ml) increase in production of [32P]PA, ‘overshoots’ in [32P]PIP and [32P]PIP2 ([32P]phosphatidylinositol 4,5-bisphosphate), and the increase in [32P]PI and secretion of ADP+ATP were abolished by forskolin (10−7 M). Forskolin stimulated total [32P]Pi uptake in resting platelets (48%), increased 32P incorporation into PIP (110%), and inhibited 32P incorporation into PI (50%). The latter inhibition was most likely considerably greater due to the forskolin-induced stimulation of [32P]Pi uptake. The changes in radioactive PA, PIP and PIP2 are regarded as being proportional with their masses in the prelabeled platelets, while the increase in PI (phosphatidylinositol) is regarded as a change in specific radioactivity, and hence in its synthesis. The results suggest that cAMP elevation inhibits the flux in the polyphosphoinositide cycle through both inhibition of PIP 5-kinase and PI synthesis. The inverse relation between forskolin-produced ΔPIP and [32P]PA production suggests that the PLC reaction is inhibited by elevated cAMP through reduction of substrate (PIP2) resynthesis, and not by inhibition of the PLC enzyme.

求助全文
通过发布文献求助,成功后即可免费获取论文全文。 去求助
来源期刊
自引率
0.00%
发文量
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信