Unexpected antagonism of deoxynivalenol and enniatins in intestinal toxicity through the Ras/PI3K/AKT signaling pathway

Deoxynivalenol (DON) is a kind of widespread traditional Fusarium mycotoxins in the environment, and its intestinal toxicity has received considerable attention. Recently, the emerging Fusarium mycotoxin enniatins (ENNs) have also been shown to frequently coexist with DON in animal feed and food with large consumption. However, the mechanism of intestinal damage caused by the two mycotoxins co-exposure remains unclear. In this study, Caco-2 cell line was used to investigate the combined toxicity and potential mechanisms of four representative ENNs (ENA, ENA(1), ENB, and ENB1) and DON. The results showed that almost all mixed groups showed antagonistic effects, particularly ENB at 1/4 IC50 (CI = 6.488). Co-incubation of ENNs mitigated the levels of signaling molecule levels disrupted by DON, including reactive oxygen species (ROS), calcium mobilization (Ca2+), adenosine triphosphate (ATP). The differentially expressed genes (DEGs) between the mixed and ENB groups were significantly enriched in the Ras/PI3K/Akt signaling pathway, including 28 up-regulated genes and 40 down-regulated genes. Quantitative real-time PCR further confirmed the lower expression of apoptotic gene in the mixed group, thereby reducing the cytotoxic effects caused by DON exposure. This study emphasizes that co-exposure of ENNs and DON reduces cytotoxicity by regulating the Ras/PI3K/Akt signaling pathway. Our results provide the first comprehensive evidence about the antagonistic toxicity of ENNs and DON on Caco-2 cells, and new insights into mechanisms investigated by transcriptomics.