# Role of macrophages in control of ocular HSV

> **NIH NIH R01** · CEDARS-SINAI MEDICAL CENTER · 2020 · $425,000

## Abstract

HSV-1 infections are very frequent in the U.S. and are a major cause of viral-induced blindness. The corneal
damage induced by HSV-1 appears to be mediated primarily by immune responses. We found that macrophages
form early and predominant infiltrates in the corneas of mice ocularly infected with HSV-1. We have also shown
that preferential expansion of the M2 macrophage subpopulation by injection of colony stimulating factor-1 (CSF-
1) reduced ocular virus replication and latency-reactivation, whereas activation of the M1 subpopulation was pro-
inflammatory and exacerbated eye disease. Analyses of the natural history of very early infiltrates in ocularly
infected mice suggest a dichotomy in the patterns of corneal infiltration by M1 and M2 macrophages that is
temporally associated with subsequent involvement of other immune responses, clearance of the virus from the
cornea, and establishment of latency. These results provide a framework for differentiating immune response-
mediated exacerbation vs. immune-mediated control of acute and latent HSV-1 infections. Based on our
published and preliminary data, our main hypothesis is that the natural variation in the activation of macrophages
towards the M1 or M2 disease-relevant phenotype plays a key role in determining induction of inflammation, eye
disease, and virus replication. Therefore, manipulation of M1 and M2 macrophage compartments can be used
to safeguard the integrity of the anterior segment of the eye including the cornea in response to infection.
Specifically, we will test whether manipulation of autophagy in the macrophage subsets can be used to control
ocular HSV-1 infection. The feasibility of the proposed studies is rooted in our strategy that utilizes conditional
knockout mice that we have generated to directly evaluate the M1 and M2 functions in vivo with regards to virus
replication in the eye, eye disease and establishment of latency-reactivation in ocularly infected mice. We will:
(1) Test if altering the phenotype of macrophage activation towards M2 in the cornea of ocularly infected mice
will lead to a reduction in primary infection, inflammatory responses and eye disease, and a reduction in latency-
reactivation; and (2) Test if inhibition of autophagy in M2 macrophages enhances eye disease and latency-
reactivation, while its inhibition in M1 macrophages decreases inflammation, eye disease and latency-
reactivation. We will determine the impact of blocking autophagy in transgenic mice expressing the anti-
autophagy gene of HSV-1 (i.e., γ34.5) under the M1 (NOS2) or the M2 (Arg1) promoters following infection with
WT HSV-1 strain McKrae or a γ34.5 deletion mutant of HSV-1 strain McKrae. In both Aims, we will further test
the mechanisms associated with amelioration of the disease process in terms of quantification of antiviral
responses, phagocytosis and/or autophagy in the macrophages and the impact on other immune infiltrates and
cytokine release.

## Key facts

- **NIH application ID:** 9969437
- **Project number:** 5R01EY024649-06
- **Recipient organization:** CEDARS-SINAI MEDICAL CENTER
- **Principal Investigator:** HOMAYON GHIASI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $425,000
- **Award type:** 5
- **Project period:** 2015-09-30 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9969437

## Citation

> US National Institutes of Health, RePORTER application 9969437, Role of macrophages in control of ocular HSV (5R01EY024649-06). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9969437. Licensed CC0.

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