AUTHOR=Li Chengyao , Bai Xue , Liu Xiaolei , Zhang Yuanyuan , Liu Lei , Zhang Lixiao , Xu Fengyan , Yang Yong , Liu Mingyuan 

TITLE=Disruption of Epithelial Barrier of Caco-2 Cell Monolayers by Excretory Secretory Products of Trichinella spiralis Might Be Related to Serine Protease

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.634185

DOI=10.3389/fmicb.2021.634185

ISSN=1664-302X

ABSTRACT=<p>The physical barrier is composed of epithelial cells which are joined together through intercellular connections. It serves to prevent pathogenic microorganisms from departing the intestinal lumen to invade the host. The excretory secretory (ES) products of <italic>Trichinella spiralis</italic> are critical for invasion. However, whether ES products of <italic>T. spiralis</italic> can act on the intestinal barrier is still unknown. In this study, the role of ES products of <italic>T. spiralis</italic> muscle larvae (<italic>Ts</italic>-ML-ES) in host invasion was studied by establishing an <italic>in vitro</italic> cell monolayers model. Barrier integrity analysis by a transmembrane resistance test and a paracellular permeability assay revealed that the <italic>Ts</italic>-ML-ES was able to destroy barrier function. It occurred <italic>via</italic> a reduction in the expression of tight junction (TJ) proteins, which was induced by serine protease. Furthermore, Western bolt analysis indicated that <italic>Ts</italic>-ML-ES reduced the expression of TJ proteins <italic>via</italic> the MAPK signaling pathway. Based on these data, we conclude that serine protease are likely the main factors from <italic>Ts</italic>-ML-ES that affect host intestinal barrier integrity by reducing the expression of TJs <italic>via</italic> the P38-MAPK signaling pathway. Serine protease in <italic>Ts</italic>-ML-ES might be a key invasion factor in <italic>T. spiralis</italic>.</p>