Abstract
Purpose :
To understand the mechanism of macrophage subtypes on ocular HSV-1 infection, we previously demonstrated that altering macrophage polarization from resting stage (M0) towards M2 leads to reduction in both primary and latent infection in comparison to induction of M1 in ocularly infected mice. Based on these observations, we implemented studies using M1-/-, M2-/-, transgenic mice lacking autophagy in their M1 or M2 and compared them to wild type (WT) mice.
Methods :
We constructed two different transgenic mice by blocking autophagy in M1 macrophages with γ34.5 gene expressed under the control of NOS2 promoter (M1) or ARG1 promoter (M2). Both male and female M1-/-, M2-/-, transgenic mice lacking autophagy in the M1, transgenic mice lacking autophagy in the M2 and WT control mice were ocularly infected with 2X105 PFU/eye of virulent HSV-1 strain McKrae or avirulent strain KOS with or without corneal scarification. Mice were evaluated for severity of eye disease, viral titers in the eye and latency-reactivation. Bone marrow experiments were conducted to validate the phenotype of mice and in-vitro viral titers. Detailed screening of various genes, cytokines and chemokines were analyzed by nanostring and Luminex.
Results :
Increased viral titers (P<0.05) and mortality was recorded for M1-/- mice as compared to WT group and M2-/- mice. Viral titers, corneal scarring and mortality were restored on adoptive transfer of M1 macrophages to M1-/- mice with no impact on latency-reactivation. M2-/- mice showed delayed reactivation (P<0.001) compared with WT mice. Loss of M1 macrophages in M1-/- mice resulted in enhanced inflammatory response as validated by nanostring and Luminex analysis as compared to other mice groups. We have also shown that blocking autophagy in M1 macrophages increased viral titers and eye disease (P<0.05) in ocularly infected mice compared with mice lacking autophagy in their M2 macrophages or WT mice.
Conclusions :
Our studies elucidate the importance of M1 macrophages in controlling the virus replication in the eyes of infected mice, preventing mortality and eye disease. We also found the importance of autophagy in protection from virus replication and eye disease in transgenic mice lacking autophagy in their M1 but not their M2 macrophages. Therefore, our data conclude the importance of M1 but not M2 macrophages in protection against ocular HSV-1 infection.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.