title: AP-1 inhibitory peptides are neuroprotective following acute glutamate excitotoxicity in primary cortical neuronal cultures.
abstract: Neuronal cell death caused by glutamate excitotoxicity is prevalent in various neurological disorders and has been associated with the transcriptional activation of activator protein-1 (AP-1). In this study, we tested 19 recently isolated AP-1 inhibitory peptides, fused to the cell penetrating peptide TAT, for their efficacy in preventing cell death in cortical neuronal cultures following glutamate excitotoxicity. Five peptides (PYC19D-TAT, PYC35D-TAT, PYC36D-TAT, PYC38D-TAT, PYC41D-TAT) displayed neuroprotective activity in concentration responses in both l- and retro-inverso d-isoforms with increasing levels of neuroprotection peaking at 83%. Interestingly, the D-TAT peptide displayed a neuroprotective effect increasing neuronal survival to 25%. Using an AP-1 luciferase reporter assay, we confirmed that the AP-1 inhibitory peptides reduce AP-1 transcriptional activation, and that c-Jun and c-Fos mRNA following glutamate exposure is reduced. In addition, following glutamate exposure the AP-1 inhibitory peptides decreased calpain-mediated alpha-fodrin cleavage, but not neuronal calcium influx. Finally, as neuronal death following glutamate excitotoxicity was transcriptionally independent (actinomycin D insensitive), our data indicate that activation of AP-1 proteins can induce cell death via non-transcriptional pathways. Thus, these peptides have potential application as therapeutics directly or for the rational design of small molecule inhibitors in both apoptotic and necrotic neuronal death associated with AP-1 activation.
authors.affiliation: Centre for Neuromuscular and Neurological Disorders, The University of Western Australia and Australian Neuromuscular Research Institute, QEII Medical Centre, Nedlands, WA, Australia. meadea01@student.uwa.edu.au
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Meade
authors.forename: Bruno P
authors.initials: BP
authors.lastname: Meloni
authors.forename: Jane
authors.initials: J
authors.lastname: Cross
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Bakker
authors.forename: Mark W
authors.initials: MW
authors.lastname: Fear
authors.forename: Frank L
authors.initials: FL
authors.lastname: Mastaglia
authors.forename: Paul M
authors.initials: PM
authors.lastname: Watt
authors.forename: Neville W
authors.initials: NW
authors.lastname: Knuckey
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity*; D018698:Glutamic Acid / Q000633:toxicity*; D006801:Humans; D008969:Molecular Sequence Data; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010446:Peptide Fragments / Q000235:genetics / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors* / Q000502:physiology; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: D018690:Excitatory Amino Acid Agonists; D018696:Neuroprotective Agents; D010446:Peptide Fragments; D018808:Transcription Factor AP-1; D018698:Glutamic Acid