JNK/Bim/Bax途径在TNF-α诱导分化PC12细胞凋亡过程中的作用机制  

Molecular Mechanism of JNK/Bim/Bax Apoptotic Pathway Induced by TNF-α in Differentiated PC12 Cells

作　　者：张岚[1] 邢达[2] 

机构地区：[1]广州医学院医学遗传与细胞生物学教研室,广州510182 [2]华南师范大学生物光子学研究院,激光生命科学教育部重点实验室,广州510631

出　　处：《生物化学与生物物理进展》2010年第4期370-380,共11页Progress In Biochemistry and Biophysics

基　　金：教育部"长江学者与创新团队计划"创新团队项目(IRT0829);国家自然科学基金(30870676;30870658);广东省自然科学基金(7117865);广州医学院博士启动基金(295031)资助项目~~

摘　　要：阿尔茨海默病(Alzheimer′s disease,AD)是一种神经系统退行性疾病,近年来许多研究发现AD与细胞凋亡关系密切,有研究证明肿瘤坏死因子(tumor necrosis factor-α,TNF-α)的合成过量会造成神经细胞的凋亡从而导致AD等神经退行性疾病的发生,然而人们对TNF-α造成神经细胞凋亡的分子机制并不了解.采用激光共聚焦扫描成像技术和荧光共振能量转移(fluorescence resonance energy transfer,FRET)技术在活细胞中实时对TNF-α诱导分化PC12细胞凋亡的信号通路进行了细致的研究.实验结果证明,TNF-α诱导的分化PC12细胞凋亡会经过线粒体和非线粒体途径,并通过激活核转录因子(NF-κB)上调Bcl-xL的表达来抑制经过线粒体的凋亡途径.进一步的研究证明,BimL会在线粒体上替换原来被Bcl-xL抑制的Bax,从而让Bax寡聚化,进而引发细胞凋亡,而c-Jun氨基末端激酶(JNK)抑制剂SP600125可以抑制Bax寡聚化.此外,在未分化PC12细胞中共表达GFP-BimL和YFP-Bax质粒,发现BimL可以促进Bax发生聚集,并且它们二者之间不是直接发生相互作用.上述结果证明,BimL在TNF-α诱导神经细胞凋亡过程中起到了重要作用,BimL在TNF-α诱导分化PC12细胞凋亡的过程中间接激活了Bax.Alzheimer＇s disease （AD） is a neurodegenerative disease. Recent years, AD has been found closely related to cell apoptosis. It is reported that the synthesis of excessive tumor necrosis factor-α （TNF-α） has been widely considered as a potential inducer of apoptosis contributing to neurodegenerative disease such as AD. However, the molecular mechanism of TNF-α-mediated apoptosis in neuron remains unclear. The signaling pathways involved in TNF-α-induced apoptosis in living differentiated PC12 cells were investigated by using confocal microscope and FRET （fluorescence resonance energy transfer） technique for the first time. Experimental results show that the TNF-α induced apoptosis in differentiated PC12 cells through ＂extrinsic＂ or death receptor-initiated pathway, and the ＂intrinsic＂ or mitochondrial pathway. NF-κB can inhibit mitochondrial pathway apoptosis through up-regulation of Bcl-xL by TNF-α induced. Further results show that BimL displaces Bcl-xLin the mitochondria and promotes Bax translocation during TNF-α-induced apoptosis. Furthermore, SP600125 （specific inhibitor of JNK） can inhibit the Bax translocation to mitochondria. Finally, Bax is found to translocate to mitochondria in Nave PC12 cells with co-expressing of GFP-BimL and YFP-Bax. The research demonstrates the important role of BimL, and reveals that BimL activate Bax indirectly during TNF-α-induced apoptosis.

关 键 词：阿尔茨海默病(AD) 肿瘤坏死因子(TNF-α) 荧光共振能量转移(FRET) BAX BimL 分化PC12细胞 

分 类 号：Q632[生物学—生物物理学]