# Oxidative stress and innate immunity impair the visual cycle

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2021 · $537,024

## Abstract

Project Summary
Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly. At present, no
therapy will restore vision with any form of AMD. To address this shortcoming, this proposal will focus on
mechanisms that could restore vision. The recycling of 11-cis-retinal (11-cRAL) by the visual cycle is an RPE
function that is essential for vision. While oxidative stress and complement are integral factors in AMD
pathophysiology, their impact on the visual cycle is undefined. The objective of this proposal is to define how
oxidative stress and innate immunity impair the visual cycle to decrease vision in AMD. The hypothesis to be
tested is that oxidative stress and impaired complement regulators Cfh and CD46 decrease the visual cycle
network. The proposed specific aims are: 1. Determine the extent that oxidative stress i) impairs Cfh to induce
inflammation which decreases visual cycle gene expression, and ii) induces Ptx3, and by regulating Cfh
abundance, prevents visual cycle decline. This aim will test the extent that decreased Cfh generates
inflammation from increased complement or MDA mediated cytokine expression to activate Stat3, which
decreases visual cycle gene expression, function, and vision, and the impact of Ptx3 on Cfh abundance to
regulate Cfh mediated inflammation. 2. Determine the extent that chronic oxidative stress impairs the visual
cycle through Notch signaling. Oxidative stress activates Notch signaling, which can induce the transcription
factor Sox9 to control the expression of a network of 6 visual cycle genes. While acute Notch signaling
increases Sox9, chronic Notch signaling decreases Sox9. This aim will explore the extent that chronic oxidative
stress activates Notch signaling, and how Notch influences visual cycle function through Sox9. 3. Determine
the extent that CD46 regulates Notch signaling and Sox9 mediated visual cycle gene function. Besides its
complement regulatory action, CD46 binds Jag1 to impede Notch signaling. Thus, decreased CD46 makes
Jag1 available to activate Notch signaling as an alternative, non-complement function. This aim will explore the
extent that decreased CD46 influences Notch signaling and visual cycle function through Jag1. Since CD46 is
not expressed in somatic rodent cells, we will use iPS RPE cells with mutations in key CD46 domains to
address this aim. These contributions are significant because if successful, novel pathways will be identified as
targets to treat vision loss in AMD. The research is innovative since we will investigate understudied areas
including mechanisms of vision loss from the synergistic impact of oxidative stress and innate immunity, the
role of Stat3, Notch, and Sox9, and unconventional, non-complement functions of complement regulators on
the visual cycle using unique, state-of-the-art genetic mice with fresh, but decisive factors that have not been
previously tested. Targeted therapy that neutralizes pathways that degrade visual cyc...

## Key facts

- **NIH application ID:** 10117256
- **Project number:** 5R01EY027691-05
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** James T Handa
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $537,024
- **Award type:** 5
- **Project period:** 2017-03-01 → 2022-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10117256

## Citation

> US National Institutes of Health, RePORTER application 10117256, Oxidative stress and innate immunity impair the visual cycle (5R01EY027691-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10117256. Licensed CC0.

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