# Hydrogen Peroxide Induce Human Cytomegalovirus Replication through the Activation of p38-MAPK Signaling Pathway

## TL;DR

This study shows that hydrogen peroxide boosts human cytomegalovirus replication by activating a specific cellular pathway, and antioxidants like NAC can counteract this effect.

## Contribution

The study reveals a novel mechanism linking hydrogen peroxide and HCMV replication via the p38-MAPK pathway.

## Key findings

- Hydrogen peroxide enhances HCMV replication by activating the MIE promoter and IE gene transcription.
- N-acetylcysteine inhibits H2O2-induced viral gene expression and replication in both cell culture and mouse models.
- The p38-MAPK pathway is activated by H2O2 and contributes to increased HCMV replication.

## Abstract

Human cytomegalovirus (HCMV) is a major risk factor in transplantation and AIDS patients, which induces high morbidity and mortality. These patients infected with HCMV experience an imbalance of redox homeostasis that cause accumulation of reactive oxygen species (ROS) at the cellular level. H2O2, the most common reactive oxygen species, is the main byproduct of oxidative metabolism. However, the function of H2O2 on HCMV infection is not yet fully understood and the effect and mechanism of N-acetylcysteine (NAC) on H2O2-stimulated HCMV replication is unclear. We, therefore, examined the effect of NAC on H2O2-induced HCMV production in human foreskin fibroblast cells. In the present study, we found that H2O2 enhanced HCMV lytic replication through promoting major immediate early (MIE) promoter activity and immediate early (IE) gene transcription. Conversely, NAC inhibited H2O2-upregulated viral IE gene expression and viral replication. The suppressive effect of NAC on CMV in an acute CMV-infected mouse model also showed a relationship between antioxidants and viral lytic replication. Intriguingly, the enhancement of HCMV replication via supplementation with H2O2 was accompanied with the activation of the p38 mitogen-activated protein kinase pathway. Similar to NAC, the p38 inhibitor SB203580 inhibited H2O2-induced p38 phosphorylation and HCMV upregulation, while upregulation of inducible ROS was unaffected. These results directly relate HCMV replication to H2O2, suggesting that treatment with antioxidants may be an attractive preventive and therapeutic strategy for HCMV.