Giardia Duodenalis Triggered Neutrophil Extracellular Traps in Goats

Abstract

Giardia duodenalis is a globally distributed zoonotic parasite primarily transmitted through the fecal-oral route, infecting various vertebrates, and the infection of which is prevalent in goats. Immune cells play a crucial role in pathogens invasion, and neutrophil extracellular traps (NETs) released by neutrophils serve as a non-specific defense mechanism against pathogens including parasites. In this study, we investigated the characteristics, components, and molecular mechanisms of goat NETs upon stimulation with G. duodenalis trophozoites. Scanning electron microscopy, immunofluorescence staining, and quantification of NETs revealed that typical goat NETs composed of DNA, citrullinated histone H3 (CitH3), and neutrophil elastase (NE) were induced by G. duodenalis trophozoites in a dose-dependent manner. Additionally, detection of reactive oxygen species (ROS) levels suggested simultaneous accumulation of ROS during Giardia infection. Furthermore, inhibitory experiments demonstrated that Giardia-induced NETs and ROS production were associated with TLR2/TLR4 signaling pathways along with NADPH oxidase (NOX), ERK1/2 and p38 MAPK signaling pathways activation. In summary, the release of goat NETs triggered by Giardia was accompanied by ROS generation, and both processes were regulated via TLR2/TLR4, NOX, ERK1/2, and p38 MAPK signaling pathways. This study highlights the role of NETs in immune responses to G. duodenalis infection while providing valuable insights for further investigations into the potential use of NETs-based strategies against this parasite.

Keywords: Giardia duodenalis, neutrophil extracellular traps, goat, reactive oxygen species