Accession Number : ADA476089


Title :   Endoplasmic Reticulum Stress as a Mediator of Neurotoxin-Induced Dopamine Neuron Death


Descriptive Note : Final rept. 30 Jun-1 Jul 2007


Corporate Author : COLUMBIA UNIV NEW YORK


Personal Author(s) : Burke, Robert E


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a476089.pdf


Report Date : Jul 2007


Pagination or Media Count : 54


Abstract : Programmed cell death (PCD) is an important mediator of neural degeneration in Parkinson's disease (PD). The goal of this proposal was to examine in vivo the possible role of ER stress, a mediator of PCD, in dopamine neuron death. This was done by studying mice with targeted deletions of CHOP, an upstream transcriptional mediator, and caspase-12, a downstream mediator, of ER stress-induced apoptosis. We have found that CHOP is universally expressed in neurotoxin models of PD, and that it is an essential mediator of apoptosis in the 6OHDA neurotoxin model. The CHOP null mutation does not, however, protect dopamine neurons in the chronic MPTP model, indicating that these two models are mediated by distinct mechanisms. Although CHOP is best known as a death mediator due to ER stress, we were unable to confirm the presence of ER stress in the 6OHDA model by analysis of BiP and the XBP-1 splice variant. Furthermore, we have shown that caspase-12 null mice are not protected from 6OHDA. Since caspase-12 is a critical mediator of PCD due to ER stress, these results suggest that the upregulation of CHOP in the 6OHDA model is not mediated by ER stress, but rather oxidative insult. In the final year of this award, we have found that homozygous JNK2/3 double null mutations diminish the induction of CHOP, indicating that the MAPK pathway regulates its expression. We have found also that JNK2 and JNK3 are essential mediators of neuron death in this neurotoxin model.


Descriptors :   *APOPTOSIS , *PARKINSONS DISEASE , MUTATIONS , NERVE CELLS , DOPAMINE , CNS DEPRESSANTS , RETICULAR FORMATION , NEUROTOXINS


Subject Categories : Anatomy and Physiology
      Medicine and Medical Research


Distribution Statement : APPROVED FOR PUBLIC RELEASE