Abstract
Purpose :
The photoreceptor cells in the retina are crucial for vision. Elucidating genes which regulate development and/or function of the photoreceptor cells is essential for understanding pathologies of various retinal diseases. We identified the deubiquitylating enzyme Otud7b as a candidate that is highly expressed in photoreceptor cells and aim to investigate its function in the mouse retina
Methods :
A microarray analysis was performed to identify genes which were highly expressed in the photoreceptor cells. We performed immunostaining of retinal sections with an anti-Otud7b antibody and analyzed the Otud7b KO retina. We compared light-exposed wild-type control (WT) and Otud7b knockout (KO) mice. Histologic sections were prepared and immunostained for Rhodopsin, M-opsin, and S-opsin. We investigated the effects of Otud7b deficiency on the retina in the MAK KO mouse, a photoreceptor degeneration model mouse. The histologic sections from these mice were immunostained for Rhodopsin and Gnat2. Immunohistochemical analyses were performed using cleaved caspase3 in the Neuro2A cell line where Otud7b was knocked-down. A luciferase assay was performed to examine NF-κB activation in Otud7b knock-down cells. Cells were treated with an inhibitor of the NF-κB pathway before and during serum starvation. These cells were then immunostained for cleaved casapse3.
Results :
We identified that Otud7b is expressed in photoreceptor cells of the retina. Otud7b KO mice raised under normal conditions did not exhibit any significant differences compared to the WT mice. On the other hand, light-exposed Otud7b KO mice were susceptible for further cone degradation. Further cone degradation was also observed in Otud7b KO mice with MAK KO background. Otud7b knockdown in cultured cells increased apoptosis upon starvation of serum. In addition, NF-κB was activated in these cells compared to the controls. However, treatment of cells with an inhibitor of the NF-κB pathway, decreased apoptosis.
Conclusions :
Our results suggest that Otud7b is required for photoreceptor survival in response to stress and may advance our understanding of the role of deubiquitination in the retina and human diseases.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.