Fumonisin B1 induces chicken heterophil extracellular traps mediated by PAD4 enzyme and P2 × 1 receptor

Abstract

Fumonisin B1 (FB1) is a common mycotoxin contamination in agricultural commodities being considered as a significant risk to human and livestock health, while the mechanism of FB1 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 FB1 on chicken heterophil extracellular traps (HETs) formation. Our result showed that FB1 induced HETs release in chicken heterophils observed via immunostaining, and it was concentration-dependent during 10 to 40 μM. Moreover, in 40 μM FB1-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, FB1 (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 FB1-triggered ROS production and HETs formation, suggesting FB1-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 FB1-triggered HETs. This study reported for the first time that 40 μM FB1 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 FB1 in immunotoxicity.

Keywords

• fumonisin B1
• chicken
• heterophil extracellular traps
• immunotoxicity