Activation of calpain precedes morphological alterations during hydrogen peroxide-induced apoptosis in neuronally differentiated mouse embryonal carcinoma P19 cell line

In order to reveal neurodegeneration elicited by reactive oxygen intermediates (ROI), neuronally differentiated cells from mouse embryonal carcinoma P19 cell line were exposed to hydrogen peroxide (H2O2) Enhanced protein-phosphorylation on tyrosine residues was detectable within 5 min of exposure to H2O2, and gradual rises in intracellular free Ca2+ level and in calpain activity were observed. Furthermore, H2O2 stimulation of differentiated P19 cells for 24 h resulted in morphological alterations in somas as well as neurites. Also, within 6 h of H2O2 treatment DNA fragmentation has been detected. Taken together, these results suggest that oxidative stress induces degradation of cytoskeletal proteins presumably resulting from increased intracellular Ca2+ concentration and subsequent activation of calpain. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.