1. The APP intracellular domain (AICD) potentiates ER stress-induced apoptosis
- Author
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Donat Kögel, Rupert Egensperger, Simone Poeschel, Steffi Chang, Caroline Bonner, Hildegard König, Jochen H. M. Prehn, Caoimhín G. Concannon, and Thorsten Müller
- Subjects
Aging ,Programmed cell death ,Time Factors ,Green Fluorescent Proteins ,Apoptosis ,Transfection ,Neuroblastoma ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Cell Line, Tumor ,Cytidine Deaminase ,Amyloid precursor protein ,medicine ,Humans ,Staurosporine ,Drug Interactions ,RNA, Messenger ,Enzyme Inhibitors ,Endoplasmic Reticulum Chaperone BiP ,Heat-Shock Proteins ,Caspase ,030304 developmental biology ,0303 health sciences ,Dose-Response Relationship, Drug ,biology ,Clusterin ,Tunicamycin ,General Neuroscience ,Endoplasmic reticulum ,Endoplasmic Reticulum Stress ,Flow Cytometry ,3. Good health ,Cell biology ,Gene Expression Regulation ,chemistry ,Unfolded Protein Response ,Unfolded protein response ,biology.protein ,Cancer research ,Thapsigargin ,Neurology (clinical) ,Geriatrics and Gerontology ,030217 neurology & neurosurgery ,Signal Transduction ,Developmental Biology ,medicine.drug - Abstract
Here we employed human SHEP neuroblastoma cells either stably or inducibly expressing the amyloid precursor protein (APP) intracellular domain (AICD) to investigate its ability to modulate stress-induced cell death. Analysis of effector caspase activation revealed that AICD overexpression was specifically associated with an increased sensitivity to apoptosis induced by the 2 endoplasmic reticulum (ER) stressors thapsigargin and tunicamycin, but not by staurosporine (STS). Basal and ER stress-induced expression of Bip/Grp78 and C/EBP-homologous protein/GADD153 were not altered by AICD implying that AICD potentiated cell death downstream or independent of the conserved unfolded protein response (UPR). Interestingly, quantitative polymerase chain reaction analysis and reporter gene assays revealed that AICD significantly downregulated messenger RNA levels of the Alzheimer's disease susceptibility gene ApoJ/clusterin, indicating transcriptional repression. Knockdown of ApoJ/clusterin mimicked the effect of AICD on ER stress-induced apoptosis, but had no discernible effect on staurosporine-induced cell death. Our data suggest that altered levels of AICD may abolish the prosurvival function of ApoJ/clusterin and increase the susceptibility of neurons to ER stress-mediated cell death, a pathway that may contribute to the pathogenesis of Alzheimer's disease.
- Published
- 2012