Deoxynivalenol upregulates hypoxia-inducible factor-1 & alpha; to promote an "immune evasion" process by activating STAT3 signaling
Abstract
Trichothecene mycotoxin deoxynivalenol (DON) negatively regulates immune response by damaging host immune system and harming the organism's health. We hypothesized that DON can initiate an active immunosuppressive mechanism similar to "immune evasion" to alter the cellular microenvironment and evade immune surveillance.
We tested this hypothesis using the RAW264.7 macrophage model. DON rapidly increased the expression of immune checkpoints PD-1 and PD-L1, inflammatory cytokine TGF-8, and key immune evasion factors STAT3, VEGF, and TLR-4, and caused cellular hypoxia.
Importantly, hypoxia-inducible factor-1 & alpha; (HIF-1 & alpha;) acts as a key regulator of DON-induced immunosuppression. HIF-1 & alpha; accumulated in the cytoplasm and was gradually transferred to the nucleus following DON treatment.
Moreover, DON activated HIF-1 & alpha; through STAT3 signaling to upregulate downstream signaling, including PD-1/PD-L1. Under DON treatment, immunosuppressive miR-210-3p, lncRNA PVT1, lncRNA H19, and lncRNA HOTAIR were upregulated by the STAT3/HIF-1 & alpha; axis.
Moreover, DON damaged mitochondrial function, causing mitophagy, and suppressed immune defenses. Collectively, DON triggered RAW264.7 intracellular hypoxia and rapidly activated HIF-1 & alpha; via STAT3 signaling, activating immune evasion signals, miRNAs, and lncRNAs, thereby initiating the key link of immune evasion.
This study offers further clues for accurate prevention and treatment of immune diseases caused by mycotoxins.