Cytotoxic effect of beta-amyloid on a human differentiated neuron is not mediated by cytoplasmic Ca2+ accumulation.
The effects of synthetic beta-amyloid (A beta1-42) on cell viability and cellular Ca2+ homeostasis have been studied in the human neuron-like NT2N cell, which differentiates from a teratocarcinoma cell line, NTera2/C1.D1, by retinoic acid treatment. NT2N viability was measured using morphological criteria and fluorescent live/dead staining and quantified using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide metabolism. A beta1-42 dose-dependently caused NT2N cell death when it was present in the cell culture for 14 days but had no effect on viability when it was present for 4 days. The lowest effective concentration was 4 microM, and the strongest effect was produced by 40 microM. Control NT2N cells produced spontaneous cytosolic Ca2+ oscillations under basal conditions. These oscillations were inhibited dose-dependently (0.4-40 microM) by A beta1-42 that was present in the cell culture for 1 or 4 days. Ca2+ wave frequency was decreased from 0.21 +/- 0.02 to 0.05 +/- 0.02/min, amplitude from 88 +/- 8 to 13 +/- 4 nM, and average Ca2+ level from 130 +/- 8 to 58 +/- 3 nM. The Ca2+ responses to 30 mM K+ and 100 microM glutamate were not different between control and A beta-treated cells. Thus, the results do not support the hypothesis that cytosolic early Ca2+ accumulation mediates A beta-induced NT2N cell death.
Gao
Z Y
ZY
Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-6082, USA.
Collins
H W
HW
Matschinsky
F M
FM
Lee
V M
VM
Wolf
B A
BA
D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects; D003593:Cytoplasm / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000494:pharmacology; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D010446:Peptide Fragments / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D013997:Time Factors; D014407:Tumor Cells, Cultured
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D018698:Glutamic Acid; D011188:Potassium; D002118:Calcium