Type
Text
Type
Dissertation
Advisor
Advisors: Obeid, Lina M.; Ge, Shaoyu; Shelly, Maya; Frohman, Michael A.; Luberto, Chiara
Date
2017-12-01
Keywords
Neurosciences, ceramide synthase, Charcot-Marie-Tooth, CMT2F, Hsp27, neuropathy, sphingolipid
Department
Department of Neuroscience | Dissertation
Language
en
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/78314
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Charcot-Marie-Tooth (CMT) disease is the most commonly inherited neurological disorder, but its molecular mechanisms remain unclear. One variant of CMT, Charcot-Marie-Tooth 2F (CMT2F), is characterized by mutations in heat shock protein 27 (Hsp27). Bioactive sphingolipids have been implicated in many neurodegenerative diseases, but it was unknown if they were dysregulated in CMT. Liquid chromatography/mass spectrometry was used to profile sphingolipids in CMT models. Hsp27 KO mice demonstrated decreases in ceramide in peripheral nerve tissue at an increased age, suggesting that sphingolipid metabolism may be involved in CMT2F. Indeed, the disease associated Hsp27 S135F mutant demonstrated decreases in mitochondrial ceramides. Given that Hsp27 is a chaperone protein, its role was examined in regulating Ceramide Synthases (CerSs), an enzyme family responsible for catalyzing generation of ceramide. Using confocal microscopy, CerSs co-localized with Hsp27, and upon the presence of S135F mutants, CerS1 lost its co-localization with mitochondria, suggesting that decreased mitochondrial ceramides result from reduced mitochondrial CerS localization rather than decreased CerS activity. Mitochondria in mutant cells appeared larger and demonstrated increased interconnectivity. Furthermore, mutant cell lines displayed decreased mitochondrial respiratory function and increased autophagic flux. Mitochondrial structural and functional changes were recapitulated by blocking ceramide generation pharmacologically. These results suggest that mutant Hsp27 decreases mitochondrial ceramide levels, producing structural and functional changes in mitochondria leading to neuronal degeneration. | 236 pages
Recommended Citation
Schwartz, Nicholas Urban, "Role and Regulation of Sphingolipids in Neuropathy" (2017). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 3808.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/3808