The neuroprotective effect of pituitary adenylate cyclase-activating polypeptide on cerebellar granule cells is mediated through inhibition of the CED3-related cysteine protease caspase-3/CPP32.
Caspase-3 knockout mice exhibit thickening of the internal granule cell layer of the cerebellum. Concurrently, it has been shown that intracerebral injection of pituitary adenylate cyclase-activating polypeptide (PACAP) induces a transient increase of the thickness of the cerebellar cortex. In the present study, we have investigated the possible effect of PACAP on caspase activity in cultured cerebellar granule cells from 8-day-old rat. Incubation of granule neurons with PACAP for 24 h promoted cell survival and prevented DNA fragmentation. Exposure of cerebellar granule cells to the specific caspase-3 inhibitor N-benzyloxycarbonyl-Asp-Glu-Val-Asp fluoromethylketone (Z-DEVD-FMK) for 24 h markedly enhanced cell survival and inhibited apoptotic cell death. Time-course studies revealed that PACAP causes a prolonged inhibition of caspase-3 activity without affecting caspase-1. Administration of graded concentrations of PACAP for 3 h induced a dose-dependent inhibition of caspase-3 activity. Incubation of granule cells with both dibutyryl-cAMP (dbcAMP) and phorbol 12-myristate 13-acetate (PMA) mimicked the inhibitory effect of PACAP on caspase-3. Cotreatment of cultured neurons with the protein kinase A inhibitor H89 and the protein kinase C inhibitor chelerythrine abrogated the effect of PACAP on caspase-3 activity. In contrast, the ERK kinase inhibitor U0126 did not affect the action of PACAP on caspase-3 activity. These data demonstrate that PACAP prevents cerebellar granule neurons from apoptotic cell death through a protein kinase A- and protein kinase C-dependent inhibition of caspase-3 activity.
Vaudry
D
D
European Institute for Peptide Research (Institut Fédératif de Recherches Multidisciplinaires sur les Peptides No. 23), Institut National de la Santé et de la Recherche Médicale U413, University of Rouen, France.
Gonzalez
B J
BJ
Basille
M
M
Pamantung
T F
TF
Fontaine
M
M
Fournier
A
A
Vaudry
H
H
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000502:physiology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009479:Neuropeptides / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051381:Rats; D017208:Rats, Wistar; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
C495403:Adcyap1 protein, rat; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D009479:Neuropeptides; D018696:Neuroprotective Agents; D009842:Oligopeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; D014660:Vasoactive Intestinal Peptide; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases