Glycogen synthase kinase 3β (GSK3β) mediates 6-hydroxydopamine-induced neuronal death
Glycogen synthase kinase 3β (GSK3β) mediates 6-hydroxydopamine-induced neuronal death
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DOI：
10.1096/fj.04-1551fje
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发表时间：
2004-05-01
期刊：
影响因子：
4.8
通讯作者：
Luo, J
中科院分区：
文献类型：
--
作者：
Chen, G;Bower, KA;Luo, J
散发性帕金森氏病(PD)的病因目前知之甚少。6-羟基多巴胺(6-OHDA)是一种PD类似物，在体内外被广泛用于建立这种神经退行性疾病的模型，但其潜在的机制仍不完全清楚。在此，我们证明了6-OHDA引起内质网(ER)应激，其特征是GRP78和GADD153(CHOP)的表达上调，前天冬氨酸氨基转移酶-12(Proaspase-12)的裂解，以及真核细胞起始因子-2α(CEF-2α)的磷酸化。糖原合成酶-3β(GSK3β)响应内质网应激，其活性受磷酸化调控。在SH-SY5Y细胞、PC12细胞和CGN中，6-OHDA显著抑制GSK3β在Ser9的磷酸化，而诱导Tyr216的过度磷酸化，但对GSK3β的表达几乎没有影响。此外，6-OHDA降低了GSK3β底物细胞周期蛋白D1的表达，并使GSK3β的上游信号成分Akt去磷酸化。蛋白磷酸酶2A(PP2A)是一种内质网应激反应磷酸酶，参与了6-OHDA诱导的GSK3β去磷酸化(Ser9)。用选择性抑制剂(锂、TDZD-8和L803-MTS)阻断GSK3β活性可阻止6-OHDA诱导的caspase-3和多聚ADP核糖聚合酶(PARP)的裂解、DNA断裂和细胞死亡。利用四环素(Tet)控制的TrkB诱导系统，我们证明了在SH-SY5Y细胞中激活TrkB可以减轻6-OHDA诱导的GSK3β去磷酸化(Ser9)，并减轻6-OHDA的神经毒性。TrkB的激活也能保护CGN免受6-OHDA的损伤。虽然抗氧化剂也提供了神经保护，但它们对6-OHDA诱导的GSK3β激活几乎没有影响。这些结果表明，GSK3β是与神经退行性疾病相关的促凋亡信号级联反应的关键中间体，因此提供了一个潜在的靶点，可用于药物干预。
The causes of sporadic Parkinson's disease (PD) are poorly understood. 6-Hydroxydopamine (6-OHDA), a PD mimetic, is widely used to model this neurodegenerative disorder in vitro and in vivo; however, the underlying mechanisms remain incompletely elucidated. We demonstrate here that 6-OHDA evoked endoplasmic reticulum ( ER) stress, which was characterized by an up-regulation in the expression of GRP78 and GADD153 (Chop), cleavage of procaspase-12, and phosphorylation of eukaryotic initiation factor-2 alpha in a human dopaminergic neuronal cell line (SH-SY5Y) and cultured rat cerebellar granule neurons (CGNs). Glycogen synthase kinase-3 beta (GSK3beta) responds to ER stress, and its activity is regulated by phosphorylation. 6-OHDA significantly inhibited phosphorylation of GSK3beta at Ser9, whereas it induced hyperphosphorylation of Tyr216 with little effect on GSK3beta expression in SH-SY5Y cells and PC12 cells (a rat dopamine cell line), as well as CGNs. Furthermore, 6-OHDA decreased the expression of cyclin D1, a substrate of GSK3beta, and dephosphorylated Akt, the upstream signaling component of GSK3beta. Protein phosphatase 2A (PP2A), an ER stress-responsive phosphatase, was involved in 6-OHDA-induced GSK3beta dephosphorylation (Ser9). Blocking GSK3beta activity by selective inhibitors ( lithium, TDZD-8, and L803-mts) prevented 6-OHDA-induced cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP), DNA fragmentations and cell death. With a tetracycline (Tet)-controlled TrkB inducible system, we demonstrated that activation of TrkB in SH-SY5Y cells alleviated 6-OHDA-induced GSK3beta dephosphorylation (Ser9) and ameliorated 6-OHDA neurotoxicity. TrkB activation also protected CGNs against 6-OHDA-induced damage. Although antioxidants also offered neuroprotection, they had little effect on 6-OHDA-induced GSK3beta activation. These results suggest that GSK3beta is a critical intermediate in pro-apoptotic signaling cascades that are associated with neurodegenerative diseases, thus providing a potential target site amenable to pharmacological intervention.