Mycotoxin Alternariol Induces Ca 2+ Dysregulation and Cell Death in Astrocytes: Mechanistic Toxicological Insights

ABSTRACT Alternariol (AOH) is a low‐molecular‐weight mycotoxin produced by Alternaria species, frequently found in cereal grains, tomatoes, and processed foods. While its genotoxic and endocrine‐disrupting effects are well established, emerging studies suggest a neurotoxic potential that remains poorly understood. Astrocytes—key regulators of neuronal support and calcium (Ca 2+ ) balance in the central nervous system (CNS)—are an underexplored target of AOH toxicity. Here, we investigated the effects of AOH on Ca 2+ signaling and viability in human astrocytes (Gibco Human Astrocyte, GHA cells). AOH exposure (25–125 μM) caused a concentration‐dependent rise in cytosolic Ca 2+ concentrations ([Ca 2+ ]ᵢ) and induced significant cytotoxicity. These effects were reversed by the intracellular Ca 2+ chelator BAPTA‐AM, suggesting a Ca 2+ ‐dependent mechanism. Mechanistically, AOH mobilized Ca 2+ from the endoplasmic reticulum (ER), as shown by thapsigargin blockade, and facilitated extracellular influx via store‐operated calcium entry (SOCE), inhibited by 2‐APB (a SOCE inhibitor) and GF109203X (a protein kinase C, PKC inhibitor). Notably, inhibition of phospholipase C (PLC) by U73122 completely abolished the Ca 2+ rise, implicating the PLC–ER axis as a key upstream trigger. Together, our findings reveal a novel Ca 2+ ‐dependent mechanism by which AOH disrupts astrocyte homeostasis, providing new insights into its neurotoxic potential and highlighting Ca 2+ signaling as a potential therapeutic target in glial toxicology.