The work titled “Toxoplasma gondii infection induces extracellular vesicle miRNAs in synaptic plasticity and neural mechanisms”, published on Extracellular Vesicles and Circulating Nucleic Acids (published on January 9, 2026), describes how a common infection manipulates the behaviour and brain function of its hosts. This study explored a new angle by looking at nanoparticles called extracellular vesicles, which cells use to send messages to one another, and carry small regulatory molecules known as microRNAs. To understand how the parasite alters the host, the investigators examined how these molecules change during infection and how they might affect the brain. When compared to uninfected neuron-derived cells, vesicles released from infected cells contained changes in several microRNAs altered by the parasite, including one called hsa-miR-4645-3p, which increased noticeably during infection.
By examining the genes and pathways influenced by these microRNAs, the study found that many of the microRNAs are involved in essential brain processes such as how neurons communicate, how the brain adapts and forms new connections, and how it responds to inflammation. Some of the most affected pathways included those linked to neurotrophins, which support neuron growth and survival, and hormone-related signalling that helps regulate brain activity. The analysis also highlighted pathways connected to learning and memory, suggesting that these molecular changes could help explain why T. gondii infection has been associated with shifts in behaviour, cognition, and even certain neuropsychiatric conditions.
Overall, the findings point to a new mechanism by which the parasite may influence the brain: by altering the microRNAs carried in extracellular vesicles, it may subtly reshape neuronal communication and function. This work broadens our understanding of how infectious diseases can affect the nervous system and opens new possibilities for studying—and potentially intervening in—parasite-related neurological changes.
DOI: ​​​​​​​10.20517/evcna.2025.34