title: A cyclic peptide that binds p75(NTR) protects neurones from beta amyloid (1-40)-induced cell death.
abstract: The current study determined the ability of a p75(NTR) antagonistic cyclic peptide to rescue cells from beta amyloid (Abeta) (1-40)-induced death. p75(NTR)-, p140(trkA)-NIH-3T3 cells or E17 foetal rat cortical neurones were incubated with 125I-NGF or 125I-Abeta (1-40) and increasing concentrations of the cyclic peptide (CATDIKGAEC). Peptide ability to displace 125I-NGF or 125I-Abeta (1-40) binding was determined. Duplicate cultures were preincubated with CATDIKGAEC (250 nM) or diluent and then stimulated with Abeta (1-40). Peptide ability to displace Abeta (1-40) binding, interfere with Abeta (1-40)-induced signalling and rescue cells from Abeta-mediated toxicity was determined by immunoprecipitation and autoradiography, Northern blotting, JNK activation, MTT and trypan blue assays. The peptide inhibited NGF and Abeta (1-40) binding to p75(NTR), but not to p140(trkA). Abeta (1-40) induced c-jun transcription (57.3% +/- 0.07%) in diluent-treated p75(NTR)-cells, but not in cells preincubated with the cyclic peptide. Also, at 250 nM, the peptide reduced Abeta (1-40)-induced phosphorylation of JNK by 71.8% +/- 0.03% and protected neurones against Abeta-induced toxicity as determined by: trypan blue exclusion assay (53% +/- 11% trypan blue-positive cells in diluent pretreated cultures vs. 28% +/- 5% in cyclic peptide-pretreated cultures); MTT assay (0.09 +/-0.03 units in diluent-pretreated cells vs. 0.12 +/- 0.004 units in cyclic peptide-pretreated cells); and visualization of representative microscopic fields. Our data suggest that a cyclic peptide homologous to amino acids 28-36 of NGF known to mediate binding to p75(NTR) can interfere with Abeta (1-40) signalling and rescue neurones from Abeta (1-40)-induced toxicity.
authors.affiliation: Department of Dermatology, Boston University School of Medicine, Boston, MA 02118-2394, USA. myaar@bu.edu
authors.forename: M
authors.initials: M
authors.lastname: Yaar
authors.forename: S
authors.initials: S
authors.lastname: Zhai
authors.forename: I
authors.initials: I
authors.lastname: Panova
authors.forename: R E
authors.initials: RE
authors.lastname: Fine
authors.forename: P B
authors.initials: PB
authors.lastname: Eisenhauer
authors.forename: J K
authors.initials: JK
authors.lastname: Blusztajn
authors.forename: I
authors.initials: I
authors.lastname: Lopez-Coviella
authors.forename: B A
authors.initials: BA
authors.lastname: Gilchrest
mesh_terms: D016229:Amyloid beta-Peptides / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D015152:Blotting, Northern; D016923:Cell Death / Q000187:drug effects*; D002460:Cell Line; D006801:Humans; D047468:Immunoprecipitation; D048670:MAP Kinase Kinase 4 / Q000187:drug effects / Q000378:metabolism; D020932:Nerve Growth Factor / Q000037:antagonists & inhibitors / Q000737:chemistry; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000737:chemistry / Q000494:pharmacology*; D010446:Peptide Fragments / Q000187:drug effects / Q000378:metabolism; D010456:Peptides, Cyclic / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D020917:Receptor, trkA / Q000187:drug effects / Q000378:metabolism; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor / Q000037:antagonists & inhibitors*
chemical_list: D016229:Amyloid beta-Peptides; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor; C078592:amyloid beta-protein (1-40); C068313:Ngfr protein, rat; D020932:Nerve Growth Factor; D020917:Receptor, trkA; D048670:MAP Kinase Kinase 4