title: Caspase-2 and caspase-8 trigger caspase-3 activation following 6-OHDA-induced stress in human dopaminergic neurons differentiated from ReNVM stem cells.
abstract: OBJECTIVE
  The purpose of the study was to establish a suitable model to study Parkinson's disease (PD) pathogenesis in differentiated dopaminergic neurons (dDCN). The specific aim was to demonstrate the involvement of the caspase family and to identify specific caspases which are activated by 6-hydroxydopamine (6OHD) treatment leading to death of dDCN.
  
  
  METHODS
  ReNcell VM cells were differentiated into dDCN and were exposed to 6OHD to induce stress. Western blot (WB) and double immunofluorescent analyses of caspases-2, -3, and -8 were carried out in untreated and 6OHD-treated dDCN. zVADfmk was used to determine if it could inhibit activation of caspases-2, -3, and -8 in dDCN following 6OHD-mediated stress.
  
  
  RESULTS
  Our immunofluorescent and WB data showed that 6OHD triggered caspases-2 and -8 activation which in turn activated caspase-3 leading to death of dDCN. Additionally, WB analysis revealed that caspases-2, -3, and -8 activation was reduced by zVADfmk in 6OHD-treated cells.
  
  
  CONCLUSIONS
  The study showed that 6OHD-induced toxicity triggered caspase mediated death of dDCN. This finding is in support of previous studies using different PD model showing that 6OHD can induce caspases-2 and -3 activation through apoptotic pathway and that both caspases can activate caspase-3 in PD. In addition, our results suggest that caspase-2 cause's cell death might be via an indirect NF kappaB route. This study has established a PD model which can provide better insight to PD pathogenesis on a biochemical and molecular level, leading to a better understanding of PD and potential for new treatments.
authors.affiliation: Institute of Biomedical and Environmental Science and Technology, Department of Life Sciences, Faculty of Creative Arts, Technologies and Science, Park Square, University of Bedfordshire, UK.
authors.forename: Zohara L
authors.initials: ZL
authors.lastname: Chaudhry
authors.forename: Bushra Y
authors.initials: BY
authors.lastname: Ahmed
mesh_terms: D018663:Adrenergic Agents / Q000633:toxicity; D017209:Apoptosis / Q000502:physiology; D015153:Blotting, Western; D053143:Caspase 2 / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism*; D002454:Cell Differentiation; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D059290:Dopaminergic Neurons / Q000201:enzymology*; D004789:Enzyme Activation / Q000502:physiology; D005455:Fluorescent Antibody Technique; D006801:Humans; D016627:Oxidopamine / Q000633:toxicity; D020734:Parkinsonian Disorders; D013234:Stem Cells / Q000166:cytology*
chemical_list: D018663:Adrenergic Agents; D016627:Oxidopamine; C490360:CASP2 protein, human; C505530:CASP8 protein, human; D053143:Caspase 2; D053181:Caspase 8; D003546:Cysteine Endopeptidases