Preeclamptic placentae release factors that damage neurons in vitro

Prenatal development is a critical period for programming of neurological disease. Preeclampsia, a pregnancy complication involving oxidative stress in the placenta, has been associated with long-term health implications for the child, including an increased risk of developing schizophrenia and autism spectrum disorders in later life. We have shown previously, in a rodent model of placental oxidative stress, that culture medium conditioned by the placenta alters neuronal characteristics when applied to primary cortical cultures in vitro and mimics many of the neurodevelopmental changes observed in the offspring brain. To further investigate if molecules released by the placenta may be important mediators in foetal programming of the brain, we analysed if placental tissue delivered from patients with preeclampsia secreted molecules that could affect cortical cells in culture. Application of culture medium conditioned by preeclamptic placentae to mixed cortical cultures caused changes in neurons and astrocytes that were related to key changes observed in brains of patients with schizophrenia and autism, including effects on dendrite lengths, astrocyte number as well as glutamate and GABA receptors. Treatment of the placental explants with an antioxidant prevented neuronal abnormalities. Furthermore, we identified that bidirectional communication between neurons and astrocytes, potentially via glutamate, is required to produce the effects of preeclamptic placenta medium on cortical cells. Analysis of possible signalling molecules in the placenta conditioned medium showed that the secretion profile of extracellular microRNA, small posttranscriptional regulators, was altered in preeclampsia and partially rescued by antioxidant treatment of the placental explants. Predicted targets of these differentially abundant microRNAs were linked to neurodevelopment and the placenta. The presented study provides further evidence that the diseased placenta may release factors that damage cortical cells in the brain and suggests the possibility of targeted antioxidant treatment of the placenta to prevent neurodevelopmental disorders. Total RNA was extracted from culture medium that had been conditioned by placental explants and analysed for microRNA content. Explants were derived from preeclamptic (PE) or non-diseased (ND) women and exposed to blank-NPs or MitoQ-NPs or no NPs. Samples were derived from 6 different conditions: ND+noNP, ND+blankNP, ND+MitoQNP, PE+noNP, PE+blankNP, PE+MitoQNP. Four biological replicates were measured per condition, except for PE+MitoQNP, for which 3 replicates were measured.