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Principal Investigator: Edmund Au
Organization: COLUMBIA UNIVERSITY HEALTH SCIENCES
Fiscal Year: 2024
Award: $200,442
Funding agency: National Institute of Mental Health
PROJECT SUMMARY:
Fragile X Syndrome (FXS) is a common genetic form of intellectual disability that is frequently co-morbid
with autism-like clinical features. It is caused by epigenetic silencing of the FMR1 gene, which encodes for
the protein FMRP, an RNA binding protein with a strong preference for mRNAs important in synaptic
structure and function. Indeed, there are well-documented synaptic defects observed in both human patients
and in the mouse model for FXS (Fmr1 knockout). In excitatory pyramidal neurons, these synaptic defects
are well-described but much less is known about the remaining 20% of cortical neurons, inhibitory cortical
interneurons, in FXS. Since interneuron dysfunction has been implicated in both schizophrenia as well as
ASD, they are an appealing cell population to study in the context of FXS. Our Central Hypothesis is that
cortical interneurons dysfunction plays an important role in FXS etiology and that interneuron phenotypes
can be revealed at the cell type numbers, distribution and synaptic levels. In this proposal, we will conduct
a multi-level analysis of interneurons in Fmr1-/- mice using a number of novel approaches that we recently
developed. The proposed work is Highly Significant in that interneurons are poorly understood in the
context of FXS despite their importance in the etiology of other neurodevelopmental disorders. The work
is also Highly Innovative because it brings to bear a number of novel approaches to unearth interneuron
phenotypes in FXS: detailed spatial analysis of interneuron distribution and machine learning strategies to
examine interneurons synapses at the individual and population level. First, we will use automated seg-
mentation and positional registration to study interneuron subtype numbers, layering and cortical distribu-
tion in Fmr1-/- and controls. Second, we will employ a novel machine learning pipeline to measure inter-
neuron synaptic target specificity in Fmr1 mutant and controls. Third, we will - in a manner similar to
single cell RNA-seq principle component analysis - analyze individual synaptic boutons by multidimen-
sional spatial feature analysis. This allows us to perform unsupervised cluster analysis of interneuron syn-
aptic boutons and reveal population level differences between Fmr1-/- and control synapses. Taken together,
our data will shed new light on an understudied cell population – cortical interneurons - in FXS etiology
and open new avenues of investigation into synaptic defects underlying FXS and ASD.
Terms: <3-D><3-Dimensional><3D><ASD><Address><Animals><Atlases><Autism><Autistic Disorder><Axon><Axon Terminals><Basket Cell><Brain><Brain Nervous System><CGG repeat><Causality><Cell Body><Cell Count><Cell Number><Cells><Cerebral cortex><Clinical><Cluster Analyses><Cluster Analysis><Connector Neuron><Consensus><Cyclicity><Data><Defect><Dendrites><Dendritic Spines><Disease><Disorder><Distal><Dysfunction><Early Infantile Autism><Encephalon><Escalante syndrome><Etiology><Excitatory Synapse><FMR-1 Protein><FMR1 Protein><FMR1 gene><FMRP><FMRP protein><FRAXA><Fragile X><Fragile X Mental Retardation 1 Gene><Fragile X Mental Retardation Protein><Fragile X Syndrome><Functional disorder><Future><Genetic><Grain><Human><Image><Individual><Infantile Autism><Inhibitory Synapse><Intellectual disability><Intellectual functioning disability><Intellectual limitation><Intercalary Neuron><Intercalated Neurons><Interneurons><Internuncial Cell><Internuncial Neuron><Investigation><KO mice><Kanner's Syndrome><Knock-out><Knock-out Mice><Knockout><Knockout Mice><Link><Long-Term Potentiation><Longterm Potentiation><Machine Learning><Martin-Bell Syndrome><Martin-Bell-Renpenning syndrome><Measures><Mental Depression><Messenger RNA><Methods><Mice><Mice Mammals><Modeling><Modern Man><Murine><Mus><Mutant Strains Mice><Myoepithelial cell><Nerve Cells><Nerve Unit><Neural Cell><Neurocyte><Neurodevelopmental Disorder><Neurological Development Disorder><Neurons><Null Mouse><Patients><Periodicity><Phenotype><Physiopathology><Play><Population><Presynaptic Nerve Endings><Presynaptic Terminals><Probability><Pyramidal neuron><RNA-Binding Proteins><Regulation><Renpenning syndrome 2><Resolution><Rhythmicity><Role><Schizophrenia><Schizophrenic Disorders><Sensory><Spatial Distribution><Specificity><Standardization><Stereotyping><Structure><Synapses><Synaptic><Synaptic Boutons><Synaptic Terminals><Techniques><Testing><Work><X-linked mental deficiency-megalotestes syndrome><X-linked mental retardation with fragile X syndrome><X-linked mental retardation-fragile site 1 syndrome><autism spectral disorder><autism spectrum disorder><autism-fragile X (AFRAX) syndrome><autistic spectrum disorder><auto-segmentation><automated segmentation><automatic segmentation><autosegmentation><causation><cell type><co-morbid><co-morbidity><comorbidity><confocal imaging><dementia praecox><dendrite spine><density><depression><developmental disease><developmental disorder><disease causation><epigenetic gene silencing><epigenetic silencing><excitatory neuron><fra(X) syndrome><fra(X)(28) syndrome><fra(X)(q27) syndrome><fra(X)(q27-28) syndrome><fragile X FMR1 protein><fragile X mental retardation 1><fragile X mental retardation-1 protein><fragile X-mental retardation syndrome><fragile Xq syndrome><fragile site mental retardation 1><hippocampal pyramidal neuron><imaging><in vivo><inhibitory neuron><innovate><innovation><innovative><intellectual and developmental disability><learning activity><learning method><learning strategies><learning strategy><limited intellectual functioning><mRNA><machine based learning><machine learning based pipeline><machine learning pipeline><macro-orchidism-marker X (MOMX) syndrome><macro-orchidism-marker X syndrome><mar(X) syndrome><marker X syndrome><mental retardation-macroorchidism syndrome><methods to study multiple-level influences><mouse model><mouse mutant><multi-level analysis><multi-level model><multilevel analysis><multilevel model><multilevel modeling><murine model><mutant><neural cell body><neurodevelopmental disease><neuronal><neuronal cell body><new approaches><novel><novel approaches><novel strategies><novel strategy><pathophysiology><postsynaptic><preference><resolutions><scRNA-seq><schizophrenic><single cell RNA-seq><single cell RNAseq><single cell analysis><single cell expression profiling><single cell transcriptomic profiling><single-cell RNA sequencing><social role><soma><synapse><synapse function><synaptic function><three dimensional><unsupervised clustering>