Toxoplasma gondii infection induces extracellular vesicle miRNAs in synaptic plasticity and neural mechanisms

Aim: This study investigates the change in profiles of miRNAs in extracellular vesicles released during Toxoplasma gondii (T. gondii) infection. T. gondii has been implicated in host behavioural modifications and neuroinflammatory responses, yet the molecular mechanisms involved in these changes remain poorly understood. Extracellular vesicles, involved in intercellular communication, play an important role in host-pathogen interactions, particularly through the transfer of microRNAs (miRNAs); however, the impact of extracellular vesicle miRNAs in T. gondii infection remains largely unexplored. Methods: Human BE(2)-M17 neuronal cells were infected with Toxoplasma gondii to investigate infection-induced changes in extracellular vesicle (EV) miRNA content. EVs from infected and control cultures were isolated, characterised, and subjected to miRNA extraction followed by next-generation sequencing and differential expression analysis using standard bioinformatic pipelines. Predicted miRNA targets were integrated across multiple databases and analysed for enriched pathways to identify neuronal regulatory networks. Results: Pathway network analysis identified key neurobiological pathways, including neuroplasticity, neurotransmission, and neuroinflammation in high-confidence miRNA targets with gene enrichment of neurotrophin and long-term depression and long-term potentiation, which may underlie parasite-induced alterations in neural function. Bioinformatic analysis of extracellular vesicle miRNA profiles from infected and uninfected neuronal cells revealed a set of miRNAs including hsa-miR-4645-3p with significant upregulation in response to infection. Conclusion: These findings suggest that T. gondii modulates host neuronal processes through extracellular vesicle-mediated miRNA transfer, providing a potential mechanistic link between infection and parasite-associated cognitive and neuropsychiatric disturbances.