# Predicted Role of Ebola VP40-Host Interactions in Ocular Pathology and Persistence

> **NIH NIH R21** · UNIVERSITY OF PENNSYLVANIA · 2021 · $196,879

## Abstract

Ebola virus (EBOV) can cross cellular barriers, establish persistence, and re-emerge in survivors months later
in the eye, central nervous system, and semen, leading to long term pathology and sequelae. Indeed, a wide
spectrum of ocular complications, including hemorrhages, blindness, and uveitis, have been reported following
both acute EBOV infection and during long-term convalescent stages. The mechanisms by which filoviruses
enter, persist, and re-emerge in the eye remain unknown. Retinal pigment epithelial (RPE) cells are permissive
for EBOV infection and are thought to serve as the intraocular reservoir for persistence and spread of EBOV.
Based on our preliminary data, we hypothesize that EBOV VP40 (eVP40) contributes to the spread of EBOV to
the human eye by interacting with tight junctional (TJ) complex proteins in the RPE and/or corneal endothelium,
thereby weakening these barriers to facilitate virus infection and spread during acute infection, as well as during
re-emergence from a persistent state. Specifically, we have shown that the PPxY motif conserved in filovirus
VP40 proteins can interact with select host WW-domain bearing proteins that are involved in maintaining and
regulating the physical and functional integrity of cellular TJs. These VP40 interactors include MAGI3, a member
of the MAGUK superfamily of proteins, that functions as an adaptor/scaffolding protein to maintain junction
integrity and barrier function as well as YAP and TAZ; paralogues and downstream effectors of the Hippo
signaling pathway that regulate genes involved in cell proliferation and migration and junctional integrity. The
interaction of YAP/TAZ and MAGI3 with the PPxY motifs of filovirus VP40 is particularly intriguing, as these host
proteins are also regulated by the binding of their WW-domains to the N-terminal PPxY motifs of the host protein
AMOT (Angiomotin). Indeed, Amot negatively regulates YAP activity by binding and sequestering YAP at TJs,
and promotes TJ assembly and integrity by interacting with the MAGI family of scaffolding proteins. Since Amot,
via its PPxY motifs, appears to be a “master regulator” of TJ formation and function, we hypothesize that the
PPxY motifs of filovirus VP40 may compete with those of Amot to disrupt TJ formation and function in virus
infected cells, thereby enhancing cellular permeability and virus spread. In this high risk, high impact proposal,
we will use a powerful and innovative eye-on-a-chip technology to provide a human cell-based model system
with an unprecedented level of physiological realism to investigate: 1) the role of VP40 in altering the most
essential barriers of the human eye, and 2) to determine whether our previously validated PPxY inhibitors not
only can block VP40-mediated egress and spread, but also prevent VP40-mediated disruption of TJ barriers and
disease progression in these eye models. This exploratory and innovative approach will provide new
fundamental insights into the molecular mechanis...

## Key facts

- **NIH application ID:** 10135976
- **Project number:** 5R21EY031465-02
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** RONALD N HARTY
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $196,879
- **Award type:** 5
- **Project period:** 2020-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10135976

## Citation

> US National Institutes of Health, RePORTER application 10135976, Predicted Role of Ebola VP40-Host Interactions in Ocular Pathology and Persistence (5R21EY031465-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10135976. Licensed CC0.

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