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