Peffer, Melanie
(2014)
Analysis of glucocorticoid action in neural stem cells.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Approximately one-eighth of women in the United States go into pre-term labor and are prescribed synthetic glucocorticoids (GCs) to minimize complications of prematurity and increase the likelihood of fetal survival. Despite these beneficial effects, GCs have permanent negative consequences on brain development, which may lead to neuropsychiatric disorders such as post-traumatic stress disorder, depression and anxiety later in life. The mechanistic bases for these GC induced neurodevelopmental changes are unknown. Therefore, we used neural progenitor/stem cells isolated from the cerebral cortex (CC-NPSCs) or hypothalamus (HT-NPSCs), to identify novel mechanisms for how GCs could impact the developing brain.
In CC-NPSCs, we identified a role for Caveolin-1 (Cav-1) in mediating crosstalk between the rapid and genomic actions of the glucocorticoid receptor (GR). Using Cav-1 KO mice, we identified approximately 100 genes, that are differentially responsive to GC treatment in the Cav-1 KO CC-NPSCs. Therefore, we established a role for Cav-1 in regulating the genomic action of GR. Phosphorylation of the GR impacts its genomic action, and GC-induced phosphorylation of GR at Serine 211, but not Serine 226 was altered in the Cav-1 KO. Using chromatin immunoprecipitation experiments, we determined that pSer211-GR recruitment to certain target genes was altered in Cav-1 KO CC-NPSCs. Therefore, we propose that Cav-1 dependent GC action impacts hormone regulated transcription through its influence on site-specific phosphorylation of GR.
RNA-Seq analysis of male/female HT-NPSCs treated with Dexamethasone (Dex, a synthetic GC) identified sexually dimorphic GR regulated genes. Using candidates from the RNA-Seq analysis, we identified GC mediated programming effects on Fkbp5 and H19. In response to a previous exposure to Dex, female, but not male, HT-NPSCs re-treated with Dex have attenuated induction of the Fkbp-5 gene. H19 was similarly GC-regulated in both male and female, but previous treatment with Dex resulted in GC-mediated repression instead of activation. Since H19 harbors a miRNA implicated in regulation of stem cell proliferation, changes in its regulation may be a contributing factor in the altered proliferative response to Dex seen in pre-treated HT-NPSCs. Therefore, HT-NPSCs exposed to Dex exhibit sexually dimorphic and long lasting changes in gene expression and NPSC function.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
28 April 2014 |
| Date Type: |
Publication |
| Defense Date: |
21 April 2014 |
| Approval Date: |
28 April 2014 |
| Submission Date: |
28 April 2014 |
| Access Restriction: |
3 year -- Restrict access to University of Pittsburgh for a period of 3 years. |
| Number of Pages: |
136 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
School of Medicine > Integrative Molecular Biology |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Glucocorticoid Receptor
Dexamethasone
Neurosphere
Neural stem/progenitor cell
caveolin-1
neuropsychiatric disorder |
| Date Deposited: |
28 Apr 2014 15:07 |
| Last Modified: |
28 Apr 2017 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/21507 |
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