Can these mycotoxins increase oxidative stress, disrupt immune signaling, and injure the gut and mitochondria?

Exposure to foodborne and environmental mycotoxins—including ochratoxin A (OTA), gliotoxin, fumonisins, and trichothecenes—triggers a cascade of cellular, immunological, and barrier damage.

Cellular and mitochondrial mechanisms

• Mitochondrial collapse and oxidative stress: These toxins compromise mitochondrial membrane potential, leading to severe ATP depletion and elevated reactive oxygen species (ROS). This structural mitochondrial damage further perpetuates ROS generation, creating a cycle of oxidative stress.
• Glutathione depletion: The toxins consume intracellular glutathione (GSH) through direct conjugation and oxidation. OTA compounded this by suppressing glutamate-cysteine ligase (GCL, the rate-limiting enzyme in GSH synthesis) and other Nrf2-regulated enzymes, while gliotoxin alters the GSH/GSSG ratio. Supplementation with N-acetylcysteine (NAC) helps rescue cellular viability by restoring GSH pools.
• Immune signaling disruption: Gliotoxin acts as an immunosuppressor by inhibiting the 20S proteasome, stabilizing I$\kappa$B$\alpha$, and blocking NF-$\kappa$B nuclear translocation. Trichothecenes cause ribotoxic stress, activating mitogen-activated protein kinases (MAPKs like p38, JNK, ERK) and inducing Suppressor of Cytokine Signaling (SOCS) proteins to suppress JAK-STAT pathway activation. OTA similarly impairs IL-2/IL-2 receptor signaling.

Physiological and barrier consequences

• Gut barrier injury: OTA, fumonisins, and trichothecenes impair the intestinal epithelium (demonstrated by decreased transepithelial electrical resistance) by downregulating, mislocalizing, or degrading essential tight junction proteins, specifically claudins, occludin, and ZO-1. This structural barrier failure is fundamentally driven by mitochondrial ATP depletion, as tight junction maintenance is highly energy-dependent.

Bottom line

• Ochratoxin A, gliotoxin, fumonisins, and trichothecenes collectively disrupt cellular homeostasis through interconnected pathways: they deplete mitochondrial ATP and glutathione reserves, drive oxidative stress, compromise intestinal tight junctions, and impair critical immune signaling pathways.