Distinct signaling pathways of precursor BDNF and mature BDNF in cultured cerebellar granule neurons
Distinct signaling pathways of precursor BDNF and mature BDNF in cultured cerebellar granule neurons
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DOI：
10.1016/j.neulet.2010.02.055
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发表时间：
2010-04-12
影响因子：
2.5
通讯作者：
Kojima, Masami
中科院分区：
文献类型：
--
作者：
Koshimizu, Hisatsugu;Hazama, Shunsuke;Kojima, Masami
最近的研究集中在前体脑源性神经营养因子(ProBDNF)和成熟BDNF(MatBDNF)的生物活性之间的鲜明对比。本研究利用抗蛋白水解性切割的proBDNF突变体(CR-proBDNF)，分析了proBDNF促凋亡和matBDNF抗低钾(LK)诱导的小脑颗粒神经元(CGN)死亡的信号机制。时程研究表明，与matBDNF不同，CR-proBDNF在长达360分钟的时间内未能诱导TrkB的磷酸化。CR-proBDNF不激活参与TrkB诱导的细胞存活信号的ERK-1、ERK-2和Akt，而matBDNF激活这些激酶。另一方面，CR-proBDNF处理CGNS后，RAC-GTP酶迅速激活，JNK磷酸化，参与了p75(NTR)诱导的细胞凋亡。此外，JNK特异性抑制剂SP600125可抑制CR-proBDNF诱导的细胞凋亡，但不影响matBDNF的抗凋亡作用。CR-proBDNF处理可使caspase-3活性提前出现。相反，matBDNF显著推迟了活性caspase-3的出现。与其他信号分子不同，caspase-3的激活受CR-proBDNF和matBDNF的反向调节。这些结果表明，在CGNS中，proBDNF通过激活p75(NTR)、Rac-GTPase、JNK和caspase-3来诱导细胞凋亡，而matBDNF通过激活TrkB、ERKs和Akt以及去激活caspase-3来诱导细胞存活。(C)2010爱思唯尔爱尔兰有限公司。保留所有权利。
Recent studies have focused on a distinctive contrast between bioactivities of precursor brain-derived neurotrophic factor (proBDNF) and mature BDNF (matBDNF). In this study, using a proteolytic cleavage-resistant proBDNF mutant (CR-proBDNF), signaling mechanisms underlying the proapoptotic effect of proBDNF and antiapoptotic effect of matBDNF on the low potassium (LK)-inducing cell death of cultured cerebellar granule neurons (CGNs) were analyzed. A time course study demonstrated that unlike matBDNF, CR-proBDNF failed to induce TrkB phosphorylation for up to 360 min. CR-proBDNF did not activate ERK-1, ERK-2 and Akt, which are involved in TrkB-induced cell survival signaling, while matBDNF activated these kinases. On the other hand treatment of CGNs with CR-proBDNF led to a rapid activation of Rac-GTPase and phosphorylation of JNK which are involved in p75(NTR)-induced apoptosis. In addition, a JNK-specific inhibitor, SP600125, inhibited the CR-proBDNF-induced apoptosis but did not affect the antiapoptotic effect of matBDNF. CR-proBDNF treatment led to an earlier appearance of active caspase-3. In contrast, matBDNF dramatically postponed the appearance of active caspase-3. Not like other signaling molecules, activation of caspase-3 was conversely regulated by both CR-proBDNF and matBDNF. These results thus suggest that in CGNs proBDNF elicits apoptosis via activation of p75(NTR), Rac-GTPase, JNK, and caspase-3, while matBDNF signals cell survival via activation of TrkB, ERKs and Akt, and deactivation of caspase-3. (C) 2010 Elsevier Ireland Ltd. All rights reserved.