# The Role of Aquaporin-0 in Lens Development and Aging

> **NIH NIH R01** · VANDERBILT UNIVERSITY · 2020 · $368,000

## Abstract

The human lens must maintain transparency over many decades and, to do so without a blood supply, the lens
maintains a fluid microcirculation system to deliver nutrients throughout the tissue. Recently, MRI imaging of
water movement has revealed a barrier to water movement in the lens inner cortex that we hypothesize is an
important feature of the microcirculation system. However, the molecular details of how this microcirculation
system is established and maintained with age are not completely understood. Lens membrane proteins, such
as transporters, channels and adhesion molecules, likely play essential roles in the development and
maintenance of lens transparency via the microcirculation system. We hypothesize that lens aquaporins
(AQPs) play important roles in generating the lens microcirculation system by generating regional differences
in water permeability and by establishing an extracellular diffusion barrier. Aquaporin-0 (AQP0) is the most
abundant lens membrane protein with reported roles in lens fiber cell adhesion, in water permeability, and in
fiber cell organization and, as such, is vital for the development and maintenance of lens transparency. A
second aquaporin, AQP5, is also present in lens fiber cells; however, its role in fiber cell function is unclear.
The long-term goal of our research is to understand how lens protein modifications that occur during
development, aging, and cataractogenesis lead to lens transparency or opacification. In the context of the
microcirculation system, we hypothesize that posttranslational modifications and AQP-lipid interactions are
important molecular mechanisms used to modulate AQP functionality in each lens region. In addition, we
hypothesize that AQP5 trafficking is carefully controlled by posttranslational modification in response to
mechanical or osmotic stress. To test our hypotheses we will employ water permeability and cell adhesion
assays, native mass spectrometry and proteomics analyses, as well as multi-modal imaging methods to obtain
a molecular level understanding of how the structures and functions of lens AQPs change in specific lens
regions. We propose three region-specific aims: 1) in the outer cortex of human lenses, use mass
spectrometry methods and functional assays to determine AQP structure, function, and regulation; 2) in the
extracellular barrier region, use magnetic resonance imaging of lens water movement, super resolution
microscopy to map extracellular space, imaging mass spectrometry to map changes to AQPs and lens lipids
and functional assays top assess AQP function; and 3) in the core of human lenses, identify AQP modifications
and determine the functional roles of modified AQP0 and AQP5. We expect to provide a new molecular level
understanding of the lens microcirculation system and the roles of AQPs and their modifications in maintaining
lens transparency.

## Key facts

- **NIH application ID:** 9906222
- **Project number:** 5R01EY013462-19
- **Recipient organization:** VANDERBILT UNIVERSITY
- **Principal Investigator:** Kevin L Schey
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $368,000
- **Award type:** 5
- **Project period:** 2001-05-01 → 2022-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9906222

## Citation

> US National Institutes of Health, RePORTER application 9906222, The Role of Aquaporin-0 in Lens Development and Aging (5R01EY013462-19). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/9906222. Licensed CC0.

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