Altered oligodendrocyte structure and function is implicated in major mental illnesses, including low density and reduced expression of oligodendrocyte-specific gene transcripts in major depressive disorder (MDD). These features are also observed in the unpredictable chronic mild stress (UCMS) and chronic corticosterone (CORT) rodent models of the illness; however, whether oligodendrocyte changes are a causal component of MDD is not known. The oligodendrocyte-specific gene 2-3-cyclic nucleotide-3-phosphodiesterase (CNP1) is a key component of axoglial communication and has previously been implicated in psychiatric disorders. A recent study in our lab found decreased levels of CNP1 in the amygdala (a central region of mood regulation) of human post-mortem MDD subjects and mice exposed to UCMS.
In an attempt to determine whether altered CNP1 (or disrupted oligodendrocyte integrity) represents a causal factor in MDD, we investigated MDD-related features in mice lacking CNP1 (CNP1KO mice). In terms of technical development, we: 1) initiated use of a novel Z-score normalization procedure to counteract variability and extract a more comprehensive and translational view of our behavioral analyses, and 2) propose that the fear conditioning paradigm can be used to assess corticolimbic dysfunctions relating to mechanisms of MDD. Together, our studies in CNP1KO mice reveal a surprising profile of behavioral resilience that is accompanied by patterns of amygdala-related dysfunction. In addition, we show robust upregulation of oligodendrocyte and immune related transcripts in the basolateral amygdala of CNP1KO mice. This pattern is suggestive of compensatory changes for oligodendrocyte structure/function and indicative of an association between oligodendrocytes and immune function. Together, these studies demonstrate that disruption of oligodendrocyte function (via CNP1 ablation) can impact circuits mediating emotionality in mice resulting in abnormal affective behaviors. However, downstream molecular changes combined with the observation of longterm detrimental consequences in these mice (e.g. neurodegeneration), is suggestive of a maladaptive role for CNP1 in MDD.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-08042011-110435 |
| Date | 11 August 2011 |
| Creators | Edgar, Nicole M. |
| Contributors | Dr. Irwin Lucki, Dr. Etienne Sibille, Dr. David Lewis, Dr. J. Patrick Card, Dr. Gregg Homanics, Dr. Floh Thiels |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-08042011-110435/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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