MPP+-induced neuronal death in rats involves tyrosine 33 phosphorylation of WW domain-containing oxidoreductase WOX1.
WW domain-containing oxidoreductase (named WWOX, FOR or WOX1) is a pro-apoptotic protein and tumor suppressor. Animals treated with dopaminergic neurotoxin 1-methyl-4-phenyl-pyridinium (MPP+) develop Parkinson's disease (PD)-like symptoms. Here we investigated whether WOX1 is involved in MPP+-induced neurodegeneration. Upon insult with MPP+ in rat brains, WOX1 protein was upregulated and phosphorylated at Tyr33 (or activated) in the injured neurons in the striatum and cortex ipsilaterally to intoxication, as determined by immunohistochemistry and Western blotting. Also, WOX1 was present in the condensed nuclei and damaged mitochondria of degenerative neurons, as revealed by transmission immunoelectron microscopy. Time-lapse microscopy revealed that MPP+ induced membrane blebbing and shrinkage of neuroblastoma SK-N-SH cells. Dominant-negative WOX1, a potent inhibitor of Tyr33 phosphorylation, abolished this event, indicating a critical role of the phosphorylation in apoptosis. c-Jun N-terminal kinase (JNK1) is known to bind and counteract the apoptotic function of WOX1. Suppression of JNK1 function by a dominant-negative spontaneously induced WOX1 activation. WOX1 physically interacted with JNK1 in SK-N-SH cells and rat brain extracts. MPP+ rapidly increased the binding, followed by dissociation, which is probably needed for WOX1 to exert apoptosis. We synthesized a short Tyr33-phosphorylated WOX1 peptide (11 amino acid residues). Interestingly, this peptide blocked MPP+-induced neuronal death in the rat brains, whereas non-phospho-WOX1 peptide had no effect. Together, activated WOX1 plays an essential role in the MPP+-induced neuronal death. Our synthetic phospho-WOX1 peptide prevents neuronal death, suggestive of its therapeutic potential in mitigating the symptoms of PD.
Lo
Chen-Peng
CP
Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan 70101, ROC.
Hsu
Li-Jin
LJ
Li
Meng-Yen
MY
Hsu
Se-Yei
SY
Chuang
Jih-Ing
JI
Tsai
Ming-Shu
MS
Lin
Sing-Ru
SR
Chang
Nan-Shan
NS
Chen
Shur-Tzu
ST
D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D006801:Humans; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010300:Parkinson Disease / Q000201:enzymology / Q000473:pathology / Q000628:therapy; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000235:genetics / Q000378:metabolism*; D000074584:WW Domain-Containing Oxidoreductase
D025521:Tumor Suppressor Proteins; D014443:Tyrosine; D010088:Oxidoreductases; D000074584:WW Domain-Containing Oxidoreductase; C486071:WWOX protein, human; D015655:1-Methyl-4-phenylpyridinium