The viral vectors we develop for delivery of transgenes to brain are often applicable to other systems, such as lung, and liver-based gene therapy. We focus our studies on understanding the limitations of the vector systems for the particular tissue, and developing ways to overcome those limitations. We utilize molecular virology, cell biology, life models, and molecular genetics to manipulate the vector systems under
study. We have developed a technique to modify the targeting of the adeno-associated virus (AAV) to allow gene transfer tools to act upon specific tissues. We utilize phage-panning to
identify peptides that bind to regions of interest in life models of disease. These peptides are then incorporated into the capsid proteins of the AAVs, allowing for new viral targeting.
Our utilizaion of RNAi as a tool for gene knockdown began with our studies to reduce the mutant genes of Spinocerebellar Ataxia and Huntington's Disease. Since these early studies we have made great improvements to our RNAi design. Originally using short hairpin RNAs (shRNAs),we have shifted to designing RNAi tools that resemble endogenous microRNAs (miRNAs). Our studies have shown improved gene targeting and reduced toxicity from the use of these artificial miRNAs. In the process of our studies to knockdown target genes we have observed some shRNAs and miRNAs appeared to be toxic to cells. We believe these effects are due to off-target binding of the artificial miRNAs. In an attempt to reduce the chance for off-target binding, we developed a tool that shows the potential number of off-target mRNAs a miRNA might have in a cell. We have turned this idea into a web based application, siSPOTR, in order to assist others in the field develop miRNAs that have mimimal off-target binding. The tool can be found at https://sispotr.icts.uiowa.edu/.
Our research into gene transfer and RNAi for central nervous diseases have lead to studies investigating the roles miRNAs play in healthy and diseased individuals. We are working to manipulate these non-coding RNAs for therapies. Additionally, we are looking at the differential profiles of miRNA expression and targets in genetic disease and the roles miRNAs have in neurodegenerative disorders.
RNAi prevents and reverses phenotypes induced by mutant human ataxin-1.
Keiser MS, Monteys AM, Corbau R, Gonzalez-Alegre P, Davidson BL. Ann Neurol. 2016 Sep 30. doi: 10.1002/ana.24789 (Abstract)
CRISPR/Cas9 Editing of the Mutant Huntingtin Allele In Vitro and In vivo Monteys AM, Ebanks SA, Keiser MS, Davidson BL. Molecular Therapy 2017 Jan 05. doi: 10.1016/j.ymthe.2016.11.010 (Full text)