Abstract
Purpose :
Piezo1, an ion channel activated by mechanical stimuli, is important due to its proprioceptive role and response to fluid pressure and touch. Before the discovery of Piezo1, little was known about the mechanisms behind mechanotransduction in the vertebrate specimen. The goal of this study is to characterize the expression patterns and properties of Piezo1 channels in the zebrafish retina.
Methods :
In order to investigate Piezo1 expression in the zebrafish, protein expression levels of Piezo1 were characterized in zebrafish retina using immunoblotting and immunohistochemistry. An antibody specific for Piezo1 mechanosensitive ion channels (Rb anti-Piezo1, Alomone Labs) was used for immunoblotting and immunohistochemical localization in the retina. In addition, various synaptic and cell type specific markers were used to determine which structures and cells were labeled with Peizo1. Specificity was determined using a preadsorptive control peptide and Piezo1 mutant zebrafish. All images were acquired using a confocal microscope and analyzed for fluorescence intensity.
Results :
Preadsorption of the Peizo1 antibody with the immunogen abolished Peizo1 immunoreactivity in the retina. Piezo1 expression was localized to cell bodies in the inner segments of cone photoreceptors and the outer plexiform layer. Strong immunoreactivity for Piezo1 was also observed in amacrine and ganglion cells in the inner retina, with the somata displaying the strongest labeling, and little or no labeling observed at either amacrine or ganglion cell processes.
Conclusions :
The expression profile suggests that a yet undiscovered role of mechanosensitive channels may exist in both inner and outer retinal neurons. Our findings support the hypothesis that mechanosensitive channels, like Piezo1 could serve a critical role in regulating pressure induced mechanosensitivity in the retina. In particular, Piezo1 may be involved in regulating apoptotic influx of Ca2+ in a disease like glaucoma. Taken together, these findings support a potential role for Piezo1 channels in mediating Ca2+ mediated apoptosis at the onset of elevated intraocular pressure in glaucoma.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.