earticle

영어

Entamoeba histolytica is anenteric tissue-invasion protozoan parasite that causes amoebic colitis and occasionally liver abscess in humans. E. histolytica can induce host cell apoptosis by the induction of various intracellular signal mechanisms. These modulations triggered by E. histolytica are closely associated with tissue pathogenesis and parasitic immune evasion mechanism. O-GlcNAcyation, similar to phosphorylation, has been thought to contribute the various cellular signal processes including apoptosis and proliferation. However, it is unknown whether E. histolytica can affect the O-GlcNAc level in host cells during Entamoeba-induced cell death. In this study, we investigated whether modulation of O-GlcNAcylated protein levels in host cells is involved in HepG2 cell death induced by E. histolytica using virulent strain HM-1 and non-virulent Rahman. Co-incubation of HepG2 cells with HM-1 strain remarkably increased DNA fragmentation and LDH release compared to cells incubated with Rahman strain or medium alone. In addition, Entamoeba HM-1induced tyrosine dephosphorylation, and activation of caspases-3 and calpain in HepG2 cells. Gal-lectin-mediated amoebic adherence of live HM-1 trophozoites to the HepG2 cells decreased of O-GlcNAcylated protein levels in HepG2 cells within 2 min, while non-virulent Rahman strain did not. Indeed, E. histolytica-induced deGlcNAcylation in HepG2 cells was prevented by O-GlcNAcase inhibitors, PUGNAc or Thi-Met G. In addition, DNA fragmentation and LDH release triggered by E. histolytica HM-1 were strongly inhibited by pretreatment of host cells with OGA inhibitor PUGNAc. Our results suggest that decreased O-glycosylation is required for cell death in hepatocytes induced by adherence of E. histolytica.