Glucocorticoid receptor stimulation and the regulation of neonatal cerebellar neural progenitor cell apoptosis

Kevin K. Noguchi, Karen Lau, Derek J. Smith, Brant S. Swiney, Nuri B. Farber

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Glucocorticoids are used to treat respiratory dysfunction associated with premature birth but have been shown to cause neurodevelopmental deficits when used therapeutically. Recently, we established that acute glucocorticoid exposure at clinically relevant doses produces neural progenitor cell apoptosis in the external granule layer of the developing mouse cerebellum and permanent decreases in the number of cerebellar neurons. As the cerebellum naturally matures and neurogenesis is no longer needed, the external granule layer decreases proliferation and permanently disappears during the second week of life. At this same time, corticosterone (the endogenous rodent glucocorticoid) release increases and a glucocorticoid-metabolizing enzyme that protects the external granule layer against glucocorticoid receptor stimulation (11β-Hydroxysteroid-Dehydrogenase-Type 2; HSD2) naturally disappears. Here we show that HSD2 inhibition and raising corticosterone to adult physiological levels both can independently increase neural progenitor cell apoptosis in the neonatal mouse. Conversely, glucocorticoid receptor antagonism decreases natural physiological apoptosis in this same progenitor cell population suggesting that endogenous glucocorticoid stimulation may regulate apoptosis in the external granule layer. We also found that glucocorticoids which HSD2 can effectively metabolize generate less external granule layer apoptosis than glucocorticoids this enzyme is ineffective at breaking down. This finding may explain why glucocorticoids that this enzyme can metabolize are clinically effective at treating respiratory dysfunction yet seem to produce no neurodevelopmental deficits. Finally, we demonstrate that both acute and chronic glucocorticoid exposures produce external granule layer apoptosis but without appropriate control groups this effect becomes masked. These results are discussed in terms of their implications for glucocorticoid therapy and neurodevelopment during the perinatal period.

Original languageEnglish
Pages (from-to)356-363
Number of pages8
JournalNeurobiology of Disease
Volume43
Issue number2
DOIs
StatePublished - Aug 2011

Keywords

  • Apoptosis
  • Betamethasone
  • Bronchopulmonary dysplasia
  • Cerebellum
  • Chronic lung disease
  • Dexamethasone
  • Glucocorticoid
  • Neural progenitor cell
  • Neurodevelopment
  • Premature birth

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