title: Acute neonatal glucocorticoid exposure produces selective and rapid cerebellar neural progenitor cell apoptotic death.
abstract: There has been a growing controversy regarding the continued use of glucocorticoid therapy to treat respiratory dysfunction associated with prematurity, as mounting clinical evidence has shown neonatal exposure produces permanent neuromotor and cognitive deficits. Here we report that, during a selective neonatal window of vulnerability, a single glucocorticoid injection in the mouse produces rapid and selective apoptotic cell death of the proliferating neural progenitor cells in the cerebellar external granule layer and permanent reductions in neuronal cell counts of their progeny, the cerebellar internal granule layer neurons. Our estimates suggest that this mouse window of vulnerability would correspond in the human to a period extending from approximately 20 weeks gestation to 6.5 weeks after birth. This death pathway is critically regulated by the proapoptotic Bcl-2 family member Puma and is independent of p53 expression. These rodent data indicate that there exists a previously unknown window of vulnerability during which a single glucocorticoid exposure at clinically relevant doses can produce neural progenitor cell apoptosis and permanent cerebellar pathology that may be responsible for some of the iatrogenically induced neurodevelopmental abnormalities seen in children exposed to this drug. This vulnerability may be related to the physiological role of glucocorticoids in regulating programmed cell death in the mammalian cerebellum.
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO 63110-1093, USA. noguchik@wustl.edu
authors.forename: K K
authors.initials: KK
authors.lastname: Noguchi
authors.forename: K C
authors.initials: KC
authors.lastname: Walls
authors.forename: D F
authors.initials: DF
authors.lastname: Wozniak
authors.forename: J W
authors.initials: JW
authors.lastname: Olney
authors.forename: K A
authors.initials: KA
authors.lastname: Roth
authors.forename: N B
authors.initials: NB
authors.lastname: Farber
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D001522:Behavior, Animal / Q000502:physiology; D002531:Cerebellum / Q000166:cytology / Q000254:growth & development*; D002648:Child; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; C494773:Bak1 protein, mouse; C494827:Bax protein, mouse; D005938:Glucocorticoids; C488588:PUMA protein, mouse; D025521:Tumor Suppressor Proteins; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D003907:Dexamethasone