NF-kappaB mediates MPP+-induced apoptotic cell death in neuroblastoma cells SH-EP1 through JNK and c-Jun/AP-1.
Parkinson's disease (PD) is characterized by a progressive loss of dopaminergic neurons in substantia nigra with unknown etiology. Neuropathology seen in the brains of PD patients can be closely mimicked by MPP(+)-induced neurotoxicity in vitro. In this study, we used an S-type human neuroblastoma cell line (SH-EP1) as a model to investigate the involvement of NF-kappaB and JNK pathways in MPP(+)-induced neurotoxicity. We show that NF-kappaB was activated by MPP(+) as evidenced by NF-kappaB p65 nuclear translocation, the increased DNA binding activity and a rapid phosphorylation of NF-kappaB inhibitor (IkappaBalpha). NF-kappaB partially mediated the neurotoxicity of MPP(+), as suggested by the reduction of MPP(+)-induced cell death by both a specific IkappaB kinase (IKK) inhibitor and a dominant negative form of IkappaBalpha (IkappaBalpha-M). Besides NF-kappaB, JNK and c-Jun/AP-1 were also activated upon MPP(+) stimulation. Inhibition of JNK activation with a specific JNK inhibitor partially reduced the MPP(+)-mediated cell death. Similarly, inhibition of c-Jun/AP-1 activation, either by a dominant negative c-Jun or c-Jun/AP-1 inhibitor, significantly attenuated MPP(+)-mediated cell death. These results suggest that both JNK and c-Jun/AP-1 activation are pro-apoptotic. Furthermore, we provide clear evidence for the existence of a crosstalk between the NF-kappaB and JNK signaling as MPP(+)-induced activation of JNK and c-Jun/AP-1 was strongly down-regulated in IkappaBalpha-M cells. In conclusion, we demonstrate that in SH-EP1 cells MPP(+)-induced neurotoxicity is partially mediated by NF-kappaB which in turn acts on the activation of JNK and c-Jun/AP-1. These results may point to a combined inhibition of NF-kappaB and JNK as a new approach to PD therapy.
Yang
Hai-Jie
HJ
Genomics & Genetics Division, School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
Wang
Lei
L
Xia
Yin-Yan
YY
Chang
Piek-Ngoh
PN
Feng
Zhi-Wei
ZW
D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity; D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006540:Herbicides / Q000633:toxicity; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009410:Nerve Degeneration / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D009447:Neuroblastoma; D020734:Parkinsonian Disorders / Q000378:metabolism* / Q000503:physiopathology; D016755:Proto-Oncogene Proteins c-jun / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D051996:Transcription Factor RelA / Q000378:metabolism
D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D006540:Herbicides; D020672:I-kappa B Proteins; D016328:NF-kappa B; D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1; D051996:Transcription Factor RelA; D048031:JNK Mitogen-Activated Protein Kinases; D015655:1-Methyl-4-phenylpyridinium