Chloride secretion induced by rotavirus is oxidative stress-dependent and inhibited by Saccharomyces boulardii in human enterocytes.

Vittoria Buccigrossi,Franco Maria Ruggeri,Alfredo Guarino,Carla Russo,Marina Monini,Erasmo Miele,Morena Sofia,Gabriella Laudiero,Ravi Jhaveri

doi:10.1371/journal.pone.0099830

Vittoria Buccigrossi, Franco Maria Ruggeri + Show 7 more

Open Access

https://doi.org/10.1371/journal.pone.0099830

Copy DOI

Abstract

Rotavirus (RV) infection causes watery diarrhea via multiple mechanisms, primarily chloride secretion in intestinal epithelial cell. The chloride secretion largely depends on non-structural protein 4 (NSP4) enterotoxic activity in human enterocytes through mechanisms that have not been defined. Redox imbalance is a common event in cells infected by viruses, but the role of oxidative stress in RV infection is unknown. RV SA11 induced chloride secretion in association with an increase in reactive oxygen species (ROS) in Caco-2 cells. The ratio between reduced (GSH) and oxidized (GSSG) glutathione was decreased by RV. The same effects were observed when purified NSP4 was added to Caco-2 cells. N-acetylcysteine (NAC), a potent antioxidant, strongly inhibited the increase in ROS and GSH imbalance. These results suggest a link between oxidative stress and RV-induced diarrhea. Because Saccharomyces boulardii (Sb) has been effectively used to treat RV diarrhea, we tested its effects on RV-infected cells. Sb supernatant prevented RV-induced oxidative stress and strongly inhibited chloride secretion in Caco-2 cells. These results were confirmed in an organ culture model using human intestinal biopsies, demonstrating that chloride secretion induced by RV-NSP4 is oxidative stress-dependent and is inhibited by Sb, which produces soluble metabolites that prevent oxidative stress. The results of this study provide novel insights into RV-induced diarrhea and the efficacy of probiotics.

Highlights

Rotavirus (RV) infection is the most frequent and severe form of acute gastroenteritis in infants and children worldwide and frequently requires hospitalization [1,2]
N measured at 50 min time point. (B) Nonstructural protein 4 (NSP4) induced an increase in the in shortcircuit current (Isc) in a dose-dependent manner
The maximal Isc shown was measured at 50 min time point. (C) Caco-2 cells were infected with RV 10 pfu/cell (#) or exposed to NSP4 at 200 ng/ml ( ) and Isc was measured for 1 hours every 5 minutes

Summary

Introduction

Rotavirus (RV) infection is the most frequent and severe form of acute gastroenteritis in infants and children worldwide and frequently requires hospitalization [1,2]. Up to 40% of hospitalized children under 5 years of age with diarrhea are infected with RV [3,4]. RV infects mature enterocytes of the small intestinal villi, inducing broad functional and structural damage [7]. RV diarrhea is the result of a sequence of combined secretory and osmotic mechanisms, including overstimulation of intestinal ion transepithelial secretion and intestinal damage, leading to malabsorption and osmotic diarrhea [8,9]. NSP4 is produced by RV and induces diarrhea in mice through the release of intracellular stores of calcium from enterocytes [10]

Methods

Results

Conclusion