THE INTERPLAY BETWEEN ENDOCRINE DISRUPTION AND GENETICS IN THE PHYSIOPATHOLOGY OF HUMAN NEURODEVELOPMENT: BRIDGING EPIDEMIOLOGY TO MOLECULAR INSIGHTS THROUGH BRAIN ORGANOIDS AND HIGH RESOLUTION OMIC MODELLING

Several epidemiological studies uncovered a strong link between pre- and postnatal exposure to EDCs and impaired development of cognitive functions, attention and social behaviors in children. Nonetheless, the molecular mechanisms underlying such outcomes are yet to be detailed and EDC-induced DNT (developmental neurotoxicity) remains largely uncovered by the current testing tools in regulatory use. We thus investigated the hormonal pathways underlying EDCs-induced DNT by taking advantage of human pluripotent stem cells (hiPSC)-derived cortical brain organoids (CBOs), a model that recapitulates salient species-specific features of human brain development in a 3D microenvironment characterized by stereospecific interconnections among different cell populations. After chronically exposing CBOs to 7 different hormones, their respective antagonists and their combinations, we leveraged bulk and single cell transcriptomic, as well as imaging-based quantification of brain cortex-specific developmental populations to characterize the transcriptional and functional alterations promoted by the activation and inhibition of each hormonal pathway and thereby defining the impact of their modulation on cortical organoids physiology. Subsequently, we performed a toxicological evaluation of a battery of EDCs, chronically exposing CBOs to such compounds, employing for each one a 4 log range of concentrations linked to those inferred by epidemiological studies to extensively define their impact on human cortex development. In parallel, to allow the experimental tractability of large cohorts of genotypes, fundamental to decipher the contribution of genetic variability in neurodevelopment, we explored and benchmarked genetic multiplexing approaches that allow to grow mosaic CBOs from multiple donors.