Caspase-3 expression by cerebellar granule neurons is regulated by calcium and cyclic AMP
Caspase-3 expression by cerebellar granule neurons is regulated by calcium and cyclic AMP
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DOI：
10.1046/j.1471-4159.1999.0730568.x
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发表时间：
1999-08-01
影响因子：
4.7
通讯作者：
Pleasure, D
中科院分区：
文献类型：
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作者：
Moran, J;Itoh, T;Pleasure, D
当 8 日龄大鼠的小脑颗粒神经元 (CGN) 从细胞外浓度 25 mM K+ (25 mM [K+](e)) 转移至 5 mM [K+](e) 时，Caspase-3 酶活性被诱导，细胞死亡随之而来。 caspase-3 抑制剂可以减少这些神经元的死亡，但 caspase-1 抑制剂则不能减少这些神经元的死亡。 Actinomycin D 和 cycloheximide 抑制 caspase-3 的诱导并防止死亡。通过改变 [K+](e) 或向培养基中添加电压门控 Ca2+ 通道拮抗剂或 Ca2+ 离子载体来控制 CGN 细胞内 Ca2+ 浓度 ([Ca2+](i)) 的实验表明，当 [Ca2+](i) 从 300 nM 减少至 150 nM 时，caspase-3 mRNA 升高 2.5 倍，峰值 caspase 酶活性相应升高。虽然 caspase-3 mRNA 水平不会随着 [Ca2+](i) 的进一步减少而进一步升高，但峰值 caspase 酶活性继续增加，当 [Ca2+](i) 减少至 55 nM 时达到诱导七倍。在通过在 5 mM [K+](e) 中孵育将 [Ca2+](i) 设置为 55 nM 的 CGN 中，用毛喉素或二丁酰 3',5'-环腺苷-5'-单磷酸处理可延迟 caspase-3 诱导并减少死亡，但不会改变 [Ca2+](i)。我们的结论是，在未成熟的 CGN 中，caspase-3 转录和随后的 caspase-3 加工都是由 [Ca2+](i) 下降诱导的。提高环 AMP 含量可通过不需要增加 [Ca2+](i) 的机制延迟 caspase-3 诱导。
Caspase-3 enzyme activity is induced, and cell death follows, when cerebellar granule neurons (CGNs) from 8-day-old rats are transferred from an extracellular concentration of 25 mM K+ (25 mM [K+](e)) to 5 mM [K+](e). Death of these neurons is diminished by an inhibitor of caspase-3 but not by an inhibitor of caspase-1. Actinomycin D and cycloheximide inhibit induction of caspase-3 and prevent death. Experiments in which CGN intracellular Ca2+ concentration ([Ca2+](i)) was manipulated by either changing [K+](e) or adding a voltage-gated Ca2+ channel antagonist or a Ca2+ ionophore to the medium showed that caspase-3 mRNA rises 2.5-fold when [Ca2+](i) is diminished from 300 to 150 nM, with a corresponding rise in peak caspase enzyme activity. Whereas the caspase-3 mRNA level does not rise further with a still greater diminution in [Ca2+](i), peak caspase enzyme activity continues to increase, reaching sevenfold induction when [Ca2+](i) is reduced to 55 nM. In CGNs in which [Ca2+](i) is set at 55 nM by incubation in 5 mM [K+](e), treatment with forskolin or dibutyryl 3',5'-cyclic adenosine-5'-monophosphate delays caspase-3 induction and diminishes death but does not alter [Ca2+](i). We conclude that, in immature CGNs, both caspase-3 transcription and the subsequent processing of caspase-3 are induced by a fall in [Ca2+](i). Elevating cyclic AMP content delays caspase-3 induction by a mechanism that does not require an increase in [Ca2+](i).