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A cyclic peptide that binds p75 NTR protects neurones from beta amyloid (1–40)‐induced cell death
Author(s) -
Yaar M.,
Zhai S.,
Panova I.,
Fine R. E.,
Eisenhauer P. B.,
Blusztajn J. K.,
LopezCoviella I.,
Gilchrest B. A.
Publication year - 2007
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/j.1365-2990.2007.00844.x
Subject(s) - trypan blue , peptide , microbiology and biotechnology , chemistry , mtt assay , neurotrophin , biochemistry , biology , in vitro , receptor
The current study determined the ability of a p75 NTR antagonistic cyclic peptide to rescue cells from beta amyloid (Aβ) (1–40)‐induced death. p75 NTR ‐, p140 trkA ‐NIH‐3T3 cells or E17 foetal rat cortical neurones were incubated with 125 I‐NGF or 125 I‐Aβ (1–40) and increasing concentrations of the cyclic peptide (CATDIKGAEC). Peptide ability to displace 125 I‐NGF or 125 I‐Aβ (1–40) binding was determined. Duplicate cultures were preincubated with CATDIKGAEC (250 n m ) or diluent and then stimulated with Aβ (1–40). Peptide ability to displace Aβ (1–40) binding, interfere with Aβ (1–40)‐induced signalling and rescue cells from Aβ‐mediated toxicity was determined by immunoprecipitation and autoradiography, Northern blotting, JNK activation, MTT and trypan blue assays. The peptide inhibited NGF and Aβ (1–40) binding to p75 NTR , but not to p140 trkA . Aβ (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 n m , the peptide reduced Aβ (1–40)‐induced phsophorylation of JNK by 71.8% ± 0.03% and protected neurones against Aβ‐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 Aβ (1–40) signalling and rescue neurones from Aβ (1–40)‐induced toxicity.