ASTROCYTE-DERIVED EXTRACELLULAR VESICLES MEDIATE GLYPHOSATE-INDUCED DISRUPTION OF NEURON–GLIA COMMUNICATION

Emerging epidemiological and rodent studies link glyphosate (Gly), the active ingredient of the most widely used herbicide (Roundup®), to neurological disorders, including parkinsonisms, Alzheimer’s disease and autism spectrum disorders. Following Gly (or Roundup®) exposure, rodents exhibit neuronal and synaptic dysfunction, glutamatergic excitotoxicity, gut microbiota dysbiosis, and oxidative stress. Although Gly crosses the blood–brain barrier, how its neurotoxic effects propagate onto brain cells remains unclear. Given their bidirectional interactions with neurons and vasculature, we hypothesized that astrocytes are a key route for Gly-mediated brain-damage. Thus, we investigated whether Gly alters astrocyte–neuron communication via extracellular vesicles (EVs), nanoscale lipid bilayer vesicles enriched in bioactive molecules (e.g., miRNAs, proteins, lipids), deemed essential for neural circuits function.
Primary cortical astrocytes from neonatal mice were exposed for 24 hours to 3 μM Gly, corresponding to the EFSA’s acceptable daily intake (ADI). This induced morphological changes and increased GFAP expression, accompanied by enhanced release of astrocytes-EVs (ADEVs). When applied to cortical neurons, ADEVs (1x10⁹/mL) isolated from Gly-exposed astrocytes (Gly-ADEVs) reduced dendritic complexity and excitatory synapse density compared to vehicle-treated neurons. Conversely, ADEVs from untreated astrocytes (Ctrl-ADEVs) promoted excitatory synapses growth. Multi-electrode array and whole-cell patch-clamp recordings showed that Gly-ADEVs failed to support network activity and excitatory synaptic transmission in contrast to Ctrl-ADEVs.
These findings indicate that ADI-Gly impairs astrocyte-neuron communication in-vitro by affecting astrocyte homeostasis and ADEVs release, resulting in neuronal impairments and synaptic dysfunction. Multi-omics approaches are ongoing to identify the molecular modifications within Gly-ADEVs underlying these neuronal effects.