Regulation of neuroprotective action of vasoactive intestinal peptide in the murine developing brain by protein kinase C and mitogen-activated protein kinase cascades: in vivo and in vitro studies.
Intracerebral administration of the excitotoxin ibotenate to newborn mice induces white matter lesions mimicking periventricular leukomalacia, the most frequent brain lesion occurring in premature human babies. In this model, coinjection of vasoactive intestinal peptide prevents white matter lesions. In the present study, coadministration of ibotenate, vasoactive intestinal peptide, and selective transduction inhibitors showed that protein kinase C and mitogen-associated protein kinase pathways were critical for neuroprotection. In vivo and in vitro immunocytochemistry revealed that vasoactive intestinal peptide activated protein kinase C in astrocytes and neurons, and mitogen-associated protein kinase in neurons. In vitro neuronal transduction activation was indirect and required medium conditioned by astrocytes in which protein kinase C had been activated by vasoactive intestinal peptide. Although vasoactive intestinal peptide did not prevent the initial in vivo appearance of white matter lesion, it promoted a secondary repair of this lesion with axonal regrowth. Through protein kinase C activation, vasoactive intestinal peptide also prevented ibotenate-induced white matter astrocyte death. These data support the following hypothetical model: Vasoactive intestinal peptide activates protein kinase C in astrocytes, which promotes astrocytic survival and release of soluble factors; these released factors activate neuronal mitogen-associated protein kinase and protein kinase C, which will permit axonal regrowth.
Gressens
P
P
Service de Neuropédiatrie and INSERM CRI 97-01, Hôpital Robert-Debré, Paris, France.
Marret
S
S
Martin
J L
JL
Laquerrière
A
A
Lombet
A
A
Evrard
P
P
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D001369:Axons / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D001921:Brain / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology / Q000648:ultrastructure; D001927:Brain Diseases / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology / Q000473:pathology / Q000648:ultrastructure; D003560:Cysts / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control / Q000648:ultrastructure; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity; D007051:Ibotenic Acid / Q000633:toxicity; D007150:Immunohistochemistry; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009498:Neurotoxins / Q000633:toxicity; D011493:Protein Kinase C / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D018690:Excitatory Amino Acid Agonists; D018696:Neuroprotective Agents; D009498:Neurotoxins; D007051:Ibotenic Acid; D014660:Vasoactive Intestinal Peptide; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases