# Exploring the relationship of water flow across the RPE and mutant-MYO7A/Usher 1B

> **NIH NIH R21** · UNIVERSITY OF CALIFORNIA LOS ANGELES · 2020 · $234,000

## Abstract

Project Summary
The retinal pigment epithelium (RPE) has active transport mechanisms and epithelial junctions
that regulate water flow from the apical to the basal surface of the cell. Defects in either of
these aspects of RPE function may promote disorders, such as cystoid macular edema (CME),
and subsequent visual impairment. Usher Syndrome type 1B (USH1B), which is caused by
mutations in MYO7A, includes a relatively high incidence of CME. However, the mechanism of
CME in USH1B is unclear. Here, we propose to explore the suggestion that MYO7A is required
for normal fluid flow across the RPE. Using RPE cultures, differentiated from induced
pluripotent stem cells (iPSCs), derived from USH1B patients, we will test this suggestion and
investigate whether loss of MYO7A function results in defective localization of proteins involved
in the RPE junctional complex or in transmembrane ion and water flow. Further, we will use
these iPSC-RPE cultures to test the efficacy of currently-used medications for CME in
increasing water flow across the RPE. These studies will potentially provide novel insight into
the retinal function of MYO7A, and a better understanding of impaired vision in USH1B,
particularly that resulting from CME.

## Key facts

- **NIH application ID:** 9886098
- **Project number:** 1R21EY031109-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA LOS ANGELES
- **Principal Investigator:** DAVID S WILLIAMS
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $234,000
- **Award type:** 1
- **Project period:** 2020-01-01 → 2021-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9886098

## Citation

> US National Institutes of Health, RePORTER application 9886098, Exploring the relationship of water flow across the RPE and mutant-MYO7A/Usher 1B (1R21EY031109-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9886098. Licensed CC0.

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