Effects of cholesterol depletion on compartmentalized cAMP responses in adult cardiac myocytes.
Effects of cholesterol depletion on compartmentalized cAMP responses in adult cardiac myocytes.
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DOI：
10.1016/j.yjmcc.2010.11.015
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发表时间：
2011-03
影响因子：
5
通讯作者：
Harvey RD
中科院分区：
文献类型：
--
作者：
Agarwal SR;MacDougall DA;Tyser R;Pugh SD;Calaghan SC;Harvey RD
β1-肾上腺素能受体（β1ARs）和e型前列腺素受体（epr）在心肌细胞中均产生区隔性cAMP反应。在成年大鼠心室肌细胞中研究了胆固醇依赖性脂筏在产生这些区室化反应中的作用。β 1ar存在于脂筏和非脂筏含膜组分中，epr仅存在于非脂筏组分中。此外，β1AR激活增强了l型Ca2+电流、细胞内Ca2+瞬态和肌细胞缩短，而EPR激活没有影响，这与这些功能反应是由脂质筏结构域中发现的受体产生的cAMP调节的观点一致。使用甲基-β-环糊精通过消耗膜胆固醇来破坏脂筏并不能消除区隔行为，但它确实选择性地改变了特异性受体介导的反应。胆固醇消耗增强了β1ARs产生的功能反应的敏感性，而对EPR激活没有任何影响。使用两种不同的基于fret的生物传感器也测量了完整细胞中cAMP活性的变化：一种是II型基于pka的探针，用于监测亚细胞区室中的cAMP，包括与腔泡脂筏相关的微结构域；另一种是基于自由扩散的epac2探针，用于监测总细胞质cAMP。β1AR和EPR激活可引起两种FRET探针检测到的反应。然而，胆固醇消耗仅影响PKA探针检测到的β1AR反应。这些结果表明，脂筏本身不足以解释β1AR和EPR反应之间的差异。他们还认为，β1AR对肌细胞收缩的调节涉及与腔泡脂筏相关的受体亚群局部产生cAMP。并非所有cAMP偶联受体都能在成人心肌细胞中产生功能性反应。►功能性反应与脂筏结构域的受体相关。脂筏受体刺激PKA信号域的局部cAMP生成。非脂筏受体产生的cAMP在PKA信号域外被检测到。胆固醇消耗改变脂质筏依赖性反应，但不改变区隔。
β1-Adrenergic receptors (β1ARs) and E-type prostaglandin receptors (EPRs) both produce compartmentalized cAMP responses in cardiac myocytes. The role of cholesterol-dependent lipid rafts in producing these compartmentalized responses was investigated in adult rat ventricular myocytes. β1ARs were found in lipid raft and non-lipid raft containing membrane fractions, while EPRs were only found in non-lipid raft fractions. Furthermore, β1AR activation enhanced the L-type Ca2+ current, intracellular Ca2+ transient, and myocyte shortening, while EPR activation had no effect, consistent with the idea that these functional responses are regulated by cAMP produced by receptors found in lipid raft domains. Using methyl-β-cyclodextrin to disrupt lipid rafts by depleting membrane cholesterol did not eliminate compartmentalized behavior, but it did selectively alter specific receptor-mediated responses. Cholesterol depletion enhanced the sensitivity of functional responses produced by β1ARs without having any effect on EPR activation. Changes in cAMP activity were also measured in intact cells using two different FRET-based biosensors: a type II PKA-based probe to monitor cAMP in subcellular compartments that include microdomains associated with caveolar lipid rafts and a freely diffusible Epac2-based probe to monitor total cytosolic cAMP. β1AR and EPR activation elicited responses detected by both FRET probes. However, cholesterol depletion only affected β1AR responses detected by the PKA probe. These results indicate that lipid rafts alone are not sufficient to explain the difference between β1AR and EPR responses. They also suggest that β1AR regulation of myocyte contraction involves the local production of cAMP by a subpopulation of receptors associated with caveolar lipid rafts. ► Not all cAMP coupled receptors produce functional responses in adult cardiac myocytes. ► Functional responses correlate with receptors found in lipid rafts domains. ► Lipid raft receptors stimulate local cAMP production detected in PKA signaling domains. ► Non-lipid raft receptors produced cAMP detected outside of PKA signaling domains. ► Cholesterol depletion alters lipid raft dependent responses but not compartmentation.
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影响因子：
56.9
作者：
Nikolaev, Viacheslav O.;Moshkov, Alexey;Gorelik, Julia
通讯作者：
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影响因子：
20.1
作者：
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通讯作者：
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影响因子：
5
作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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