Ischemic preconditioning prevents ischemia-induced beta-adrenergic receptor sequestration
Ischemic preconditioning prevents ischemia-induced beta-adrenergic receptor sequestration
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DOI：
10.1016/s0022-2828(03)00173-1
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发表时间：
2003-08-01
影响因子：
5
通讯作者：
Ishikawa, Y
中科院分区：
文献类型：
--
作者：
Iwatsubo, K;Toya, Y;Ishikawa, Y
预处理对反复心肌缺血具有内源性保护作用。然而，预处理对β 1肾上腺素能受体（AR）信号的影响仍然存在争议。我们最近开发了使用全细胞的受体测定系统，其中过表达的细胞表面β AR可以容易地定量而不破坏细胞。使用这种技术，我们研究了化学/代谢性缺血对β 1 AR隔离和腺苷酸环化酶活性的影响。异丙肾上腺素处理，而不是毛喉素处理，过度表达β 1 AR的HEK 293 T细胞导致细胞表面受体数量的快速减少（2小时内），这在伴刀豆球蛋白A存在下被否定。类似地，用氰化钾和2-脱氧-D-葡萄糖（化学/代谢性缺血）处理细胞诱导类似的受体隔离。当异丙肾上腺素叠加化学/代谢性缺血，隔离的程度变得更大。然而.当细胞在前一天预先暴露于氰化钾（化学预处理）时，由异丙肾上腺素或化学/代谢缺血诱导的隔离减弱。腺苷酸环化酶的催化活性，评估与毛喉素刺激降低化学/代谢缺血，但24小时后完全恢复，表明化学/代谢缺血治疗没有改变细胞活力。总而言之，化学/代谢性缺血以与异丙肾上腺素类似的方式诱导β-AR隔离。此外，预处理防止了由异丙肾上腺素和化学/代谢性缺血引起的β-AR隔离。预处理可能通过抑制通常由缺血事件或β肾上腺素能刺激诱导的隔离而在保护细胞表面β AR中发挥作用。(C)2003年由爱思唯尔有限公司出版
Preconditioning enables endogenous protection to repeated myocardial ischemia. However, the effect of preconditioning on beta1 adrenergic receptor (AR) signal remains controversial. We have recently developed receptor assay system using whole cells, in which overexpressed cell surface beta ARs can be readily quantitated without disrupting the cell. Using this technique, we examined the effects of chemical/metabolic ischemia on the beta1 AR sequestration and adenylyl cyclase activity. Isoproterenol treatment, but not forskolin treatment, of HEK293T cells overexpressing beta1 ARs led to a rapid decrease (within 2 hours) in the number of the cell surface receptor, which was negated in the presence of concanavalin A. Similarly, treatment of cells with potassium cyanide and 2-deoxy-D-glucose (chemical/metabolic ischemia) induced similar receptor sequestration. When isoproterenol was superimposed on chemical/metabolic ischemia, the degree of sequestration became greater. However. when cells were pre-exposed to potassium cyanide on the preceding day (chemical preconditioning), the sequestration induced by either isoproterenol or chemical/metabolic ischemia was attenuated. Adenylyl cyclase catalytic activity as assessed by stimulation with forskolin was decreased by chemical/metabolic ischemia but fully recovered after 24 hours, suggesting that chemical/metabolic ischemia treatment did not alter cell viability. Putting together, chemical/metabolic ischemia induced betal AR sequestration in a similar manner to isoproterenol. In addition, preconditioning prevented the betal AR sequestration induced by both isoproterenol and chemical/metabolic ischemia. Pre-conditioning may play a role in preserving the cell surface beta ARs by inhibiting the sequestration that is usually induced by an ischemic event or beta adrenergic stimulation. (C) 2003 Published by Elsevier Ltd.