Activity-dependent neurotrophic factor: structure-activity relationships of femtomolar-acting peptides.
Activity-dependent neurotrophic factor (ADNF) is a glia-derived protein that is neuroprotective at femtomolar concentrations. A 14-amino acid peptide of ADNF (ADNF-14) has been reported that protects cultured neurons from multiple neurotoxins. Structure-activity relationships of peptides related to ADNF-14 now have been determined. A 9-amino acid core peptide (ADNF-9) has been identified that has greater potency and a broader effective concentration range (10(-16) to 10(-13) M) than ADNF or ADNF-14 in preventing cell death associated with tetrodotoxin treatment of cerebral cortical cultures. Deletions or conservative amino acid substitutions to ADNF-9 resulted in reduced potency, narrower effective concentration range and/or decreased efficacy. Removal of the N-terminal serine or the COOH-terminal isoleucine-proline-alanine from ADNF-9 produced a significant reduction in survival-promoting activity. Comparative studies of ADNF-9 action in mixed (glia plus neurons) vs. glia-depleted neuronal cultures indicated that ADNF-9 can act directly on neurons, although the potency of the peptide was 10,000-fold greater in mixed cultures. Kinetic studies showed that exposure to ADNF-9 for only 2 hr was sufficient to produce a 4-day protection against the cell-killing action of tetrodotoxin. Treatment with bafilomycin A1 (an inhibitor of receptor-mediated endocytosis) for 2 hr prevented the ADNF- and ADNF-9-mediated neuroprotection. ADNF-9, like ADNF-14, was neuroprotective against N-methyl-D-aspartate and the beta-amyloid peptide (amino acids 25-35), and had a much broader range of effective concentrations than ADNF-14. These studies identify ADNF-9 as an attractive lead compound for the development of therapeutic agents against neurodegenerative diseases.
Brenneman
D E
DE
Section on Developmental and Molecular Pharmacology, National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.
Hauser
J
J
Neale
E
E
Rubinraut
S
S
Fridkin
M
M
Davidson
A
A
Gozes
I
I
D000818:Animals; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051381:Rats; D013329:Structure-Activity Relationship
D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents