The Microscopic Imaging of Epigenetic Landscape- NeuroDevelopment (MIEL-ND) assay: a high throughput platform to screen compounds for neurodevelopmental effects

Neurodevelopmental diseasesNDDsAutism Spectrum DisorderASDIntellectual DisabilitiesBipolar disordersand Schizophreniaetcare prevalent and due to errors in neurodifferentiation and neurocircuitryWhile NDDsin many casesare due to inherited mutationsevidence is mounting that prenatal exposure to environmental toxicants also cause NDDs via disruption of epigeneticse gmodifications of histoneshistone tagsor methylation of DNAOur project will develop the Microscopic Imaging of Epigenetic LandscapeNeuroDevelopmentMIEL NDassaywhich will enable testing of chemicals for epigenetic effects related to NDDsIn preliminary research by Alexey TerskikhSanford Burnham Prebys Medical Discovery InstituteMIEL methods were developed in which human Neural Precursor CellsNPCsfrom fetal brainwere treated with test compounds and analyzed for changes in the pattern of histone tags within the nucleialteredepigenetic signaturewhich utilizes multiplexed immunolabelingautomated high throughput imagingand cell by cell analysis using machine learningA subset of chemicals from the US EPA ToxCast program was analyzedandepigenetic hitswere identifiedIn a separate approachVala Sciences Incwhich commercializes cell based assays relevant to toxicology drug discoverytested EPA compounds on synapses neurite formation in neurons developed from induced pluripotent stem cellsiPSC neuronswhich represent human neurons in early stages of maturationWhen results from the assays were comparedseveral epigenetic hits also altered synapse and neurite formation in the iPSC neurons consistent with the hypothesis that epigenetic alterations may alter fate decisions of NPCs and neurodevelopmentTo further develop the MIEL NDwe propose to screen additional ToxCast compounds for effects on epigenetic and cell fate NPCs and test the compounds for effects on synapse neurites in iPSC neurons to develop a library of epigenetic hits with known effects on the two cell typesWe will use these data and emerging data from the ToxCast programto develop and optimize the MIEL ND to predict NDD inducing effects of possible environmental toxicantsThe MIELND will identify compounds that affect neurodevelopment that are not cytotoxicwhich are missed by current assaysand represents a less expensivehigher throughputmore predictive alternative to current tests which use animalsthus reducing the use of animals in toxicity testingPhase II goals include developing a version of the MIEL ND featuring iPSC NPCsenabling use of cells derived from patients with NDDsand adaptation of the assay to identify potential therapeutics for NDDs Our proposed project will develop an assay to enable us to test environmental pollutants for their potential to cause neurodevelopmental disordersNDDssuch as AutismIntellectual DisabilityretardationBipolar DiseaseManic Depressionand SchizophreniaWhile many cases of NDDs are due to inherited mutationsthe diseaseruns in the familyrecent research indicates that exposure of the mother to pollution during pregnancy can cause NDDs in children that would otherwise be healthyThis is because development of the fetal brain is very sensitive to toxinsIn our assaycells representing early stages of brain development will be cultured in the laboratory and treated with compounds from the US EPA that are linked to NDDsThe cells will be photographed with robotic microscopes and the images analyzed with computers to determine which compounds may alter neurodevelopmentCurrentlytesting for effects on brain development of the fetus is done with animal testingOur assay will be cheapermore rapidand more predictive than animal modelssince it will use human cellsour assay will reduce the use of animals in toxicity researchwhich is a big problemas hundreds of new compounds are developedeach yearfor use in agriculture and manufacturingand help reduce the number of people afflicted with NDDs