Retinitis Pigmentosa
(RP) is an incurable inherited retinal degeneration affecting approximately 1
in 4,000 individuals globally. The aim of this dissertation was to identify
drugs that can help patients suffering from the disease. To accomplish this
goal, the zebrafish was utilized as a model for RP to perform <i>in vivo</i>
drug screening. The zebrafish RP model expresses a human rhodopsin transgene
which contains a premature stop codon at position 344 (<i>Tg</i>(<i>rho:Hsa.RH1_Q344X</i>)).
This zebrafish model exhibits significant rod photoreceptor degeneration
beginning at 7 days post fertilization (dpf). To assess the visual consequence
of this rod degeneration the zebrafish behavior visual motor response (VMR) was
assayed under scotopic conditions. The Q344X RP model larvae displayed a
deficit in this VMR in response to a scotopic light offset. This deficit in
behavior was utilized to perform a drug screen to identify compounds that could
ameliorate the deficient Q344X VMR. The ENZO SCREEN-WELL® REDOX library was
chosen to be screened since oxidative stress may increase RP progression in a
non-specific manner. From this library, a β-blocker,
carvedilol, was identified as a compound that improved the Q344X VMR behavior.
This drug was also able to increase rod number in the Q344X retina. Carvedilol
was shown to be capable of working directly on rods by demonstrating that the
drug can signal through the adrenergic pathway in the rod-like human Y79 cell
line. Since carvedilol is an FDA-approved drug, this
screening paradigm was utilized to screen the Selleckchem FDA-approved library
to identify more drugs that can potentially be repurposed to treat RP like
carvedilol. Additionally, this scotopic VMR assay was used to demonstrate that
it can identify behavioral deficits in the P23H RP model zebrafish<i> (Tg</i>(<i>rho:Hsa.RH1_P23H</i>)).
This dissertation work provides a potential FDA-approved drug for RP treatment
and sets the foundation for future drug screening to identify more drugs to
treat different forms of RP.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12252380 |
| Date | 06 May 2020 |
| Creators | Logan C Ganzen (8803004) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Drug_Screening_Utilizing_the_Visual_Motor_Response_of_a_Zebrafish_Model_of_Retinitis_Pigmentosa/12252380 |
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