Gender-specific reduction of estrogen-sensitive small RNA, miR-30b, in subjects with schizophrenia

Estrogen signaling pathways affect cortical function and metabolism, are thought to play a role in the pathophysiology of schizophrenia, and exert neuroprotective effects in female subjects at risk. However, the molecular signatures of estrogen signaling in normal and diseased cerebral cortex remain largely unexplored. Expression of the estrogen-sensitive small RNA, microRNA-30b (miR-30b), was studied in 30 controls and 30 matched samples from subjects diagnosed with schizophrenia from prefrontal cortex (PFC), as well as in 23 samples from parietal cortex (12 controls and 11 schizophrenia cases). The majority of case and control samples were genotyped for an estrogen receptor α (Esr1) sequence variant (rs2234693) previously associated with genetic risk, and a subset of them were subjected to further analysis to determine expression of mature and precursor forms of miR-30b (pre/pri-miR-30b). Gender-dimorphic expression was also explored in mouse frontal cortex and hippocampus. A significant interaction between gender and diagnosis was discovered for changes in mature miR-30b levels, so that miR-30b expression was significantly reduced in the cerebral cortex of female but not male subjects with schizophrenia. In addition, disease-related changes in miR-30b expression in a subset of female subjects were further modulated by Esr1 genotype. Changes after antipsychotic drug exposure remained insignificant. These preliminary findings point to the possibility that disease-related changes in the expression of small noncoding RNAs such as miR-30b in schizophrenia could be influenced by gender and potentially regulated by estrogen signaling.