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- All Subjects: Neurons
- Creators: Caplan, Michael
Description
Gene manipulation techniques, such as RNA interference (RNAi), offer a powerful method for elucidating gene function and discovery of novel therapeutic targets in a high-throughput fashion. In addition, RNAi is rapidly being adopted for treatment of neurological disorders, such as Alzheimer's disease (AD), Parkinson's disease, etc. However, a major challenge in both of the aforementioned applications is the efficient delivery of siRNA molecules, plasmids or transcription factors to primary cells such as neurons. A majority of the current non-viral techniques, including chemical transfection, bulk electroporation and sonoporation fail to deliver with adequate efficiencies and the required spatial and temporal control. In this study, a novel optically transparent biochip is presented that can (a) transfect populations of primary and secondary cells in 2D culture (b) readily scale to realize high-throughput transfections using microscale electroporation and (c) transfect targeted cells in culture with spatial and temporal control. In this study, delivery of genetic payloads of different sizes and molecular characteristics, such as GFP plasmids and siRNA molecules, to precisely targeted locations in primary hippocampal and HeLa cell cultures is demonstrated. In addition to spatio-temporally controlled transfection, the biochip also allowed simultaneous assessment of a) electrical activity of neurons, b) specific proteins using fluorescent immunohistochemistry, and c) sub-cellular structures. Functional silencing of GAPDH in HeLa cells using siRNA demonstrated a 52% reduction in the GAPDH levels. In situ assessment of actin filaments post electroporation indicated a sustained disruption in actin filaments in electroporated cells for up to two hours. Assessment of neural spike activity pre- and post-electroporation indicated a varying response to electroporation. The microarray based nature of the biochip enables multiple independent experiments on the same culture, thereby decreasing culture-to-culture variability, increasing experimental throughput and allowing cell-cell interaction studies. Further development of this technology will provide a cost-effective platform for performing high-throughput genetic screens.
ContributorsPatel, Chetan (Author) / Muthuswamy, Jitendran (Thesis advisor) / Helms Tillery, Stephen (Committee member) / Jain, Tilak (Committee member) / Caplan, Michael (Committee member) / Vernon, Brent (Committee member) / Arizona State University (Publisher)
Created2012
Description
Rett syndrome is a genetically based, X-linked neurodevelopmental disorder that affects 1 in 10,000 live female births. Approximately 95-97% of Rett syndrome cases are attributed to a mutation in the MECP2 gene. In the laboratory setting, key neuropathological phenotypes of Rett syndrome include small neuronal soma and nuclear size, increased cell packing density, and abnormal dendritic branching. Our lab previously created and characterized the A140V mouse model of atypical Rett syndrome in which the males are viable. Hippocampal and cerebellar granule neurons in A140V male mice have reduced soma and nuclear size compared to wild type. We also found that components of the mTOR pathway including rictor, 4E-BP-1, and mTOR, were reduced in A140V mutant mice. Quantitative PCR analysis also showed reduced IGFPB2 expression in A140V mice along with an upward trend in AKT levels that did not meet statistical significance. The objective of this study is i) to characterize the down regulation of AKT-mTOR pathway, and ii) to examine the effect of a genetic strategy to rescue mTOR pathway deficiencies in Mecp2 mutant mouse model. Genetic rescue of the mTOR pathway downregulation was done by crossing heterozygous female A140V mice with heterozygous male Tsc2 mice. Quantitative PCR analysis of A140V_Tsc2 RNA expression supported genetic rescue of mTOR pathway components, however, more testing is needed to fully characterize the rescue effect. Western blot analysis also showed reduction in phosphorylated AKT in Mecp2 A140V and T158A mutant mice, however, more testing is still needed to characterize the mTOR pathway in A140V_Tsc2 mice. Finally, other methods, such as a pharmacological approach, or transfection to increase mTOR pathway activity in cell lines, will be tested to determine if rescue of mTOR pathway activity ameliorate the Rett syndrome phenotype.
ContributorsGerald, Brittany Madison (Author) / Newbern, Jason (Thesis director) / Narayanan, Vinodh (Committee member) / Rangasamy, Sampath (Committee member) / School of Life Sciences (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12