Maternal immune activation (MIA) is a key environmental risk factor for neurodevelopmental disorders such as schizophrenia. MicroRNAs are critical regulators of brain development, yet their role in MI Show more
Maternal immune activation (MIA) is a key environmental risk factor for neurodevelopmental disorders such as schizophrenia. MicroRNAs are critical regulators of brain development, yet their role in MIA-induced pathology remains unclear. We found that miR-322-5p was significantly upregulated in the prefrontal cortex of MIA-exposed offspring and directly targeted the 3' untranslated region of brain-derived neurotrophic factor (BDNF), inhibiting its expression. This upregulation impaired BDNF/TrkB/AKT signaling and reduced the synaptic protein PSD95, leading to hypoactivity, cognitive deficits, social impairments, and disrupted sensorimotor gating. Inhibition of miR-322-5p or overexpression of BDNF in the prefrontal cortex restored signaling and reversed both behavioral and molecular abnormalities. These results identify miR-322-5p as a key mediator of MIA-induced neuropathology via repression of BDNF signaling and suggest its potential as a therapeutic target in neurodevelopmental disorders. Show less