Orexin-induced apoptosis: The key role of the seven-transmembrane domain orexin type 2 receptor
Orexin-induced apoptosis: The key role of the seven-transmembrane domain orexin type 2 receptor
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DOI：
10.1210/en.2006-0201
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发表时间：
2006-10-01
期刊：
影响因子：
4.8
通讯作者：
Laburthe, Marc
中科院分区：
文献类型：
--
作者：
Voisin, Thierry;El Firar, Aadil;Laburthe, Marc
食欲素-A 和食欲素-B 是调节肽，参与控制进食、睡眠-觉醒以及发挥各种内分泌和代谢作用。最近我们证明，作用于 OX1 受体 (OX1R) 的食欲素是促凋亡肽。本研究的目的是探讨受体亚型 OX2 R 在细胞凋亡控制中的作用。在转染 OX2R cDNA 的中国仓鼠卵巢细胞中，食欲素通过细胞凋亡引起半胱天冬酶依赖性细胞死亡，并严重抑制细胞生长。添加食欲素 (10(-6) M) 48 小时后，通过 DNA 片段化、染色质浓缩、膜联蛋白-V 结合以及 caspase-3 和 caspase-9 的激活来证明细胞凋亡。食欲素在 10(-10) 和 10(-5) M 浓度范围内对细胞凋亡和细胞生长抑制具有活性，EC50 为 5 x 10(-8) M 肽。在亲代中国仓鼠卵巢细胞中未检测到食欲素的影响。大鼠胰腺腺泡细胞系 AR42J 表达 OX2R 但不表达 OX1R，在食欲素治疗后也出现生长抑制和凋亡。 24小时后10(-6)M食欲素对AR42J细胞生长的抑制率超过75%。膜联蛋白-V标记的AR42J细胞数量的诱导是剂量依赖性的，EC50为5.1 x 10(-8) M orexin-A和9.8 x 10(-8) M orexin-B。 OX2R 激动剂 [Ala (11), D-Leu (15)]orexin-B 促进细胞生长和凋亡，这与 orexins 引起的效果相似。 OX1R 拮抗剂 SB33487 不会改变 AR42J 细胞中食欲素诱导的生长抑制或食欲素诱导的细胞凋亡刺激。我们首次提供了 OX2R 在食欲素诱导的细胞凋亡中的作用的功能和药理学证据。
Orexin-A and orexin-B are regulatory peptides involved in the control of feeding, sleep-wakefulness, and exerting various endocrine and metabolic actions. Recently we demonstrated that orexins, acting at OX1 receptor (OX1R), are proapoptotic peptides. The aim of this study was to investigate the role of the receptor subtype OX2 R in the control of apoptosis. Orexins caused a caspase-dependent cell death by apoptosis and a drastic cell growth inhibition in Chinese hamster ovary cells transfected with OX2R cDNA. On addition of either orexin (10(-6) M) for 48 h, apoptosis was demonstrated by DNA fragmentation, chromatin condensation, annexin-V binding, and activation of caspase-3 and caspase-9. Orexins were active on apoptosis and cell growth inhibition in the range of concentrations between 10(-10) and 10(-5) M with an EC50 of 5 x 10(-8) M peptides. No effect of orexins could be detected in parental Chinese hamster ovary cells. A rat pancreatic acinar cell line, AR42J, which expresses OX2R but not OX1R, also underwent growth suppression and apoptosis on treatment with orexins. Suppression of AR42J cell growth by 10(-6) M orexin was more than 75% after 24 h. Induction of annexin-V-labeled AR42J cell number was dose dependent, with EC50 of 5.1 x 10(-8) M orexin-A and 9.8 x 10(-8) M orexin-B. The OX2R agonist [Ala (11), D-Leu (15)]orexin-B promoted effects on cell growth and apoptosis, which were similar to those elicited by orexins. The OX1R antagonist SB33487 did not alter orexin-induced inhibition of growth or orexin-induced stimulation of apoptosis in AR42J cells. For the first time, we provide functional and pharmacological evidence for a role of the OX2R in orexin-induced apoptosis.