Characterization of the molecular events following impairment of NF-kappaB-driven transcription in neurons.
Nuclear factor-kappaB (NF-kappaB) is a transcription factor with a pivotal role in neuronal homeostasis. Indeed, NF-kappaB trans-activates several antiapoptotic genes in neurons and inhibition of NF-kappaB transcriptional activity triggers neuronal apoptosis. However, the exact mechanisms by which neurons undergo apoptosis in conditions of NF-kappaB inhibition are poorly understood. To further clarify how NF-kappaB operates in neurons, and to gather information on the molecular events occurring during NF-kappaB inhibition-dependent neuronal apoptosis, this study evaluated the effects of recently identified NF-kappaB inhibitors such as parthenolide, SN50, BAY 11-7082 and helenalin on primary cultures of rat cortical neurons. Data show that NF-kappaB was constitutively activated in neurons, and demonstrate for the first time that drug-dependent NF-kappaB inhibition induced rapid mitochondrial release of cytochrome c, caspase-9 and -3 activation, poly(ADP-ribose) polymerase-1 cleavage, membrane blebbing and nuclear fragmentation, without evidence of procaspase-8 and Bid processing. Interestingly, a burst of Akt activation occurred in neurons exposed to NF-kappaB inhibitors. These events were preceded by selective reduction of mRNAs of NF-kappaB-dependent, antiapoptotic Bcl-2 family members such as Bcl-x(L), Bcl-2 and, in particular, A1/Bfl-1. The present study reports a novel, detailed temporal analysis of the molecular events following impairment of NF-kappaB-driven transcription in neurons and demonstrates that inhibition of constitutive neuronal NF-kappaB activity triggers selective activation of the intrinsic apoptotic program.
Chiarugi
Alberto
A
Department of Cellular and Molecular Physiology, University of Massachusetts Medical School, Worcester, MA 01605, USA. albert_chiarugi@hotmail.com
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D006706:Homeostasis / Q000502:physiology*; D008928:Mitochondria / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009570:Nitriles; D009930:Organic Chemicals; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D011485:Protein Binding; D011498:Protein Precursors / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D051381:Rats; D051818:Replication Protein C; D012717:Sesquiterpenes / Q000494:pharmacology; D045789:Sesquiterpenes, Guaiane; D013450:Sulfones; D014158:Transcription, Genetic
C434003:3-(4-methylphenylsulfonyl)-2-propenenitrile; D000894:Anti-Inflammatory Agents, Non-Steroidal; D000970:Antineoplastic Agents; D003574:Cytochrome c Group; D004268:DNA-Binding Proteins; D016328:NF-kappa B; D009570:Nitriles; D009930:Organic Chemicals; D010455:Peptides; D011498:Protein Precursors; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C118258:SN50 peptide; D012717:Sesquiterpenes; D045789:Sesquiterpenes, Guaiane; D013450:Sulfones; C002669:parthenolide; C001329:helenalin; D004247:DNA; C499322:Parp1 protein, rat; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases; D051818:Replication Protein C