Pro-apoptotic signaling in neuronal cells following iron and amyloid beta peptide neurotoxicity.
In a previous report, we characterized several oxidative stress parameters during the course of amyloid beta (Abeta) peptide/Fe2+-induced apoptotic death in neuronal cells. In extending these findings, we now report a marked decrease in protein kinase C (PKC) isoforms, reduced Akt serine/threonine kinase activity, Bcl 2-associated death promoter (BAD) phosphorylation and enhanced p38 mitogen-activated protein kinase (MAPK) and caspase-9 and -3 activation, 12 h after addition of both 5 micro m Abeta and 5 micro m Fe2+. These activities reminiscent for a pro-apoptotic cellular course were blocked in the presence of the iron chelator deferroxamine. Abeta alone, increased PKC isoform levels between three- and four-fold after 12 h, enhanced Akt activity approximately eight-fold and Ser136 BAD phosphorylation two-fold, suggesting that by itself is not toxic. Fe2+ alone transiently enhanced p38 MAPK and caspase-9 and -3 enzymes indicative for cell damage, but was not sufficient to cause cell death as previously indicated. GF, a PKC inhibitor or wortmannin, a blocker of the Akt pathway enhanced Abeta/Fe2+-induced toxicity, while SB, a p38 MAPK inhibitor, prevented cell damage and apoptosis. These findings further support the hypothesis that metal ion chelation and inhibitors of pro-apoptotic kinase cascades may be beneficial for Alzheimer's disease therapy.
Kuperstein
Faina
F
Department of Neurobiology, The Weizmann Institute of Science, Rehovot, Israel.
Yavin
Ephraim
E
D016229:Amyloid beta-Peptides / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D003676:Deferoxamine / Q000494:pharmacology; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007501:Iron / Q000633:toxicity*; D007502:Iron Chelating Agents / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects*; D051025:bcl-Associated Death Protein; D048051:p38 Mitogen-Activated Protein Kinases
D016229:Amyloid beta-Peptides; C494821:Bad protein, rat; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D007502:Iron Chelating Agents; D007527:Isoenzymes; D011518:Proto-Oncogene Proteins; D051025:bcl-Associated Death Protein; D007501:Iron; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases; D003676:Deferoxamine