Search

Besnoitia besnoiti tachyzoites infect and develop in bovine endothelial cells in vivo and trigger the release of neutrophil extracellular traps (NETs) from bovine polymorphonuclear neutrophils (PMN). The purpose of this study was to analyze if pure B. besnoiti tachyzoite-triggered NETs would damage endothelial host cells and subsequently influence intracellular development and proliferation of B. besnoiti tachyzoites in primary bovine endothelial cells. For comparison purposes, isolated A23187-induced NETs were also used. Thus, we here evaluated endothelial host cell damage triggered by histone 2A (H2A) and B. besnoiti tachyzoite-induced NET preparations and furthermore estimated the effects of PMN floating over B. besnoiti-infected endothelium under physiological flow conditions on endothelial host cell viability. Overall, all treatments (H2A, B. besnoiti-triggered NETs and floating PMN) induced endothelial cell death of B. besnoiti-infected host cells. However, though host cell damage led to significantly altered intracellular parasite development with respect to parasitophorous vacuole diameter and numbers, the total proliferation of the parasite over time was not significantly affected by these treatments thereby denying any direct effect of NETs on intracellular B. besnoiti replication. [ABSTRACT FROM AUTHOR]

Fumonisin B 1 (FB 1 ), a worldwide contaminating mycotoxin produced by Fusarium, poses a great threat to the poultry industry. It was reported that extracellular traps could be induced by FB 1 efficiently in chickens. However, the relevance of autophagy and glycolysis in FB 1 -triggered heterophil extracellular trap (HET) formation is unclear. In this study, immunostaining revealed that FB 1 -induced HETs structures were composed of DNA coated with histones H3, and elastase, and that heterophils underwent LC3B-related autophagosome formation assembly driven by FB 1 . Western blotting showed that FB 1 downregulated the phosphorylated phosphoinositide 3-kinase3-kinase (PI3K)/protein kinase B (AKT)/mechanistic target of rapamycin complex 1 (mTORC1) axis and raised the AMP-activated kinase α (AMPKα) activation protein. Furthermore, rapamycin- and 3-Methyladenine (3-MA)-treatments modulated FB 1 -triggered HET formation according to the pharmacological analysis. Further studies on energy metabolism showed that glucose/lactate transport and glycolysis inhibitors abated FB 1 -induced HETs. These results showed that FB 1 -induced HET formation might interact with the autophagy process and relied on glucose/monocarboxylic acid transporter 1 (MCT1) and glycolysis, reflecting chicken's early innate immune responses against FB 1 intake., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Fumonisin B 1 (FB 1 ) is a common mycotoxin contamination in agricultural commodities being considered as a significant risk to human and livestock health, while the mechanism of FB 1 immunotoxicity are less understood, especially in chicken. Given that extracellular traps as a novel defense mechanism of leukocytes play an important role against foreign matters, in this study we aimed to investigate the effects of FB 1 on chicken heterophil extracellular traps (HETs) formation. Our result showed that FB 1 induced HETs release in chicken heterophils observed via immunostaining, and it was concentration-dependent during 10 to 40 μM. Moreover, in 40 μM FB 1 -exposed chicken heterophils, reactive oxygen species (ROS) level was increased, while catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity and glutathione (GSH) content were decreased. Simultaneously, FB 1 (40 μM) activated ERK and p38 MAPK signaling pathways via increasing the phosphorylation level of ERK and p38 proteins. However, pretreatment of SB202190, U0126, and diphenyleneiodonium chloride (DPI) did not change FB 1 -triggered ROS production and HETs formation, suggesting FB 1 -induced HETs was a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, p38, and extracellular regulated protein kinases (ERK) signaling pathways-independent process. Inhibition of peptidyl arginine deiminase 4 (PAD4) enzyme and P2 × 1 receptor showed their vital role in 40 μM FB 1 -triggered HETs. This study reported for the first time that 40 μM FB 1 induced the release of HETs in heterophils, and it was related to ROS production, PAD4, and P2 × 1, but was independent of NADPH oxidase, p38 and ERK signaling pathways, which might provide a whole novel perspective of perceiving and understanding the role of FB 1 in immunotoxicity., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)