Access Type

Open Access Embargo

Date of Award

January 2018

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Anatomy and Cell Biology

First Advisor

Zhuo-Hua Pan

Abstract

Recombinant adeno-associated virus (AAV) vectors are the most promising vehicles for therapeutic gene delivery to the retina. We are developing AAV-mediated expression of optogenetic tools in surviving inner retinal neurons as a potential strategy to restoring vision after the death of photoreceptor cells in retinal degeneration. Targeting optogeneitc tools, such as channelrhodopsin-2 (ChR2), to retinal bipolar cells (RBCs) is particularly attractive. In particular, our lab has recently developed an optimized mGluR6 promoter-based virus vector that can mainly target ChR2 to rod bipolar cells. However, AAV-mediated transduction efficiency in RBCs is relatively low. The transduction efficiency could be affected by a number of factors, including the physical barrier of the retina and proteasome degradation during intracellular trafficking. In this dissertation, I evaluated the effect of proteasome inhibitors on improving AAV-mediated transduction efficiency in retinal bipolar cells. My result indicated that doxorubicin, among other proteasome inhibitors, is effective in improving AAV transduction efficiency in retinal bipolar cells in a dose-dependent manner. I then evaluated doxorubicin-induced long-term toxicity to the mouse retinas and lenses. Dexrazoxane was co-administered with doxorubicin to prevent its long-term toxicity. The optimal regimen for long-term use was found to be 200-300 μM doxorubicin used in combination with dexrazoxane. I also examined the effect of plasmin on improving the AAV-mediated transduction efficiency in retinal bipolar cells. My results showed that plasmin did not improve the AAV transgene expression level in retinal bipolar cells in mice. However, middle and/or low concentration of plasmin increased the number of retinal bipolar cells that express mCherry transgene in the center and middle area of the retina. The studies will help to develop useful tools in improving the AAV-mediated transgene expression, potentially optogenetic light sensor expression, in retinal bipolar cells, which may further contribute to new clinical applications.

Available for download on Wednesday, December 11, 2019

Included in

Ophthalmology Commons

Share

COinS