Trichinella spiralis galectin disrupts gut epithelial integrity and mediates larval invasion via acting MUC13- ROCK2/MAPK pathway.

BACKGROUND

Gut epithelium serves as a critical barrier against Trichinella spiralis larval invasion, parasite-derived galectins are involved in host-parasite interactions, including invasion and immune modulation. This study investigated the role of T. spiralis galectin (Tsgal) in gut epithelial barrier disruption and larval invasion.

METHODOLOGY/PRINCIPAL FINDINGS: Recombinant Tsgal (rTsgal) was expressed in vitro and its interaction with intestinal epithelial cells (IEC) was ascertained using immunofluorescence test (IFT) and confocal microscopy. The rTsgal-specific binding IEC proteins were identified by GST pull-down, mass spectrometry (MS) and Co-immunoprecipitation (Co-IP) assay. Intestinal epithelial integrity damage induced by rTsgal was evaluated by IFT, qPCR and Western blotting analysis. The in vitro larva invasive assay was also conducted. The results showed that rTsgal bound and interacted specifically with MUC13 receptor in Caco-2 cells. rTsgal activated MUC13-ROCK2/MAPK pathway, reduced the expression of gut epithelial tight junctions (TJs; ZO-1, E-cad, Occludin and Claudin-1), increased gut epithelial permeability, disrupted gut epithelial integrity and barrier functions, thereby facilitated larva invasion of Caco-2 monolayers. Moreover, MUC13 receptor inhibitor (Cuc D), MUC13 knockdown of Caco-2 cells, ROCK2 inhibitor (KD025) and p38-MAPK inhibitor (SB203580) suppressed this pathway activation, restored gut epithelial integrity, and impeded larval invasion.

CONCLUSIONS

Tsgal disrupted gut epithelial integrity and mediated larval invasion through binding to MUC13 receptor and activating ROCK2/MAPK pathway. Tsgal might be a potential target molecule for development of novel drugs and vaccines to block T. spiralis infection.