Tetanus toxin H(C) fragment reduces neuronal MPP+ toxicity.
The non-toxic carboxi-terminal domain of the heavy chain of tetanus toxin (H(C)) elicits neuroprotection of cerebellar granule neurons against apoptotic death induced by potassium deprivation. In this study we sought to determine whether H(C) also prevents the apoptosis induced by the mitochondrial poison 1-methyl-4-phenylpyridinium (MPP+), which induces a form of Parkinsonism. Pre-treatment of cultures with H(C) prevented MPP+-induced cell death, as well as impaired the MPP+-triggered apoptotic cascade. Cytochrome c release from the mitochondria, procaspase-3 activation and chromatin condensation, were significantly reduced in H(C)-pre-treated neurons. Moreover, H(C) induced Ser(112) and Ser(136) BAD phosphorylation, which correlated with the detachment of BAD from Bcl-X(L) and its association to 14-3-3. In turn, Bcl-X(L) remained bound to Bax, impairing its translocation to mitochondria of stressed neurons. The use of Wortmannin or PD98059 demonstrated the involvement of the PI3K/Akt as well as the ERK1/2 transduction pathways in the H(C) fragment effect. Interestingly, the H(C) fragment also induces an increase in the DNA binding activity of NF-kappaB, a well-established transcription factor involved in the prevention of neuronal death. Taken together, our results strongly suggest that the recombinant H(C) fragment of tetanus toxin can act as a neuroprotector in a model of MPP(+)-triggered apoptosis.
Departament de Bioquímica i de Biologia Molecular, Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain.
Imane
I
Chaïb-Oukadour
Carles
C
Gil
José
J
Rodríguez-Alvarez
Arturo
A
Ortega
José
J
Aguilera
D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D018929:Cell Culture Techniques; D045304:Cytochromes c / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009466:Neuromuscular Blocking Agents / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013744:Tetanus Toxin / Q000494:pharmacology*
D016328:NF-kappa B; D009466:Neuromuscular Blocking Agents; D010446:Peptide Fragments; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D013744:Tetanus Toxin; C040635:tetanus toxin fragment C; D045304:Cytochromes c; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D053148:Caspase 3; D015655:1-Methyl-4-phenylpyridinium