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Principal Investigator: Chia Soo
Organization: UNIVERSITY OF CALIFORNIA LOS ANGELES
Fiscal Year: 2024
Award: $460,652
Funding agency: National Institute of Dental and Craniofacial Research
PROJECT SUMMARY
Nell-1 has been studied extensively for its osteogenic role in craniofacial skeletal development. However, despite
its high expression in the brain, there has been a lack of understanding of Nell-1's function in the nervous system
until the recent identification of a ligand-receptor like interaction between Nell-1 and Cntnap4. Cntnap4 is a pre-
synaptic membrane protein whereby global Cntnap4 loss differentially inhibits GABAergic output and augments
dopaminergic transmission, and can induce autism spectrum disorder (ASD)-like behaviors in mice. Remarkably,
ENU-induced Nell-1 haploinsufficient mice exhibit ASD-like behaviors similar to those seen in Cntnap4 mutant
mice. Meanwhile, inactivation of either Cntnap4 or Nell-1 in cranial neural crest cells (CNCCs) gives rise to
remarkably similar calvarial bone defects. Moreover, novel co-localization studies of Nell-1 and Cntnap4 in
mouse and human brains revealed broad neural tissue distribution and high levels of co-localized expression.
Consequently, this proposal hypothesizes that Nell-1 has dual roles in the brain and craniofacial bones (CB) via
a novel interaction between Nell-1 and Cntnap4, and that disruption of the Nell-1/Cntnap4 functional axis will not
only induce deficits in CB, but also interfere with neural transmission in the brain. This proposal advances three
specific aims to investigate the Nell-1/Cntnap4 functional axis in the CB and brain using two new floxed mouse
lines, Nell-1fl/fl and Cntnap4fl/fl. AIM 1 will first define the tissue distribution and expression of Nell-1 and Cntnap4
in both the CB and brain during normal development and growth in wild type (WT) mice. AIM 1 will then specify
the functional contributions of Nell-1 and Cntnap4 to the CB and brain using tissue-specific knockout (KO) Nell-
1Wnt1KO and Cntnap4Wnt1KO mice targeting CNCCs-derived CB and trigeminal ganglions (TG) by Wnt1-Cre, and
Nell-1PV-2AKO and Cntnap4PV-2AKO mice targeting parvalbumin positive (PV+) GABAergic neurons in the brain
and TG by PV-2A-Cre. The CB growth and behavioral changes in these KO mice will be correlated with
morphological changes in the examined bones, brain, and the craniofacial neuroskeletal interface where TG
sensory fibers innervate the CB. AIM 2 will decipher Nell-1's osteogenic property in the context of Cntnap4 during
the repair and regeneration of CB defects in Cntnap4Wnt1KO mice using Nell-1 protein. With Nell-1 serving as an
agonist of Wnt/β-catenin signaling, AIM 2 will determine how integrin β1, a Nell-1 binding partner, and glycogen
synthase kinase-3β (GSK3β), a crucial regulator of β-catenin phosphorylation, modulate Nell-1/Cntnap4
interaction-mediated Wnt/β-catenin signaling activation during CNCC osteogenesis. AIM 3 will investigate Nell-
1/Cntnap4 interaction on brain GABAergic transmission and ASD-like behaviors in Nell-1PV-2AKO and Cntnap4PV-
2AKO mice. AIM 3 will further assess Wnt/β-catenin signaling in the context of Nell-1/Cntnap4 interaction-
mediated GABA release, along with the possible additive or synergistic effects of GSK3β inhibitors with Nell-1 in
mouse neuronal cells. IMPACT: The ultimate goal is to reveal how the newly identified Nell-1/Cntnap4 interaction
may translate into developing Nell-1 as a novel therapeutic to treat human skeletal and neurological pathologies.
Terms: <1-Ethyl-1-nitrosourea><21+ years old><4-Aminobutanoic Acid><4-Aminobutyric Acid><4-amino-butanoic acid><ASD><Adult><Adult Human><Agonist><Aminalon><Aminalone><Autism><Autistic Disorder><Behavior><Behavior assessment><Behavioral><Beta Cadherin-Associated Protein><Beta-1 Catenin><Binding><Body Tissues><Bone Formation><Bone Growth><Bone Regeneration><Brain><Brain Nervous System><Breeding><CUL-2><Calvaria><Cell Body><Cell Communication and Signaling><Cell Signaling><Cell surface><Cells><Cephalic><Connector Neuron><Cranial><Craniosynostosis><Data><Defect><Development><Drug or chemical Tissue Distribution><ENU><Early Infantile Autism><Embryo><Embryonic><Encephalon><Ethylnitrosourea><Event><Exhibits><Fiber><Frontal Bone><Frontal bone structure><GABA><GABA Agonists><GABA Receptor Agonists><GSK-3beta><GSK-3β><Gasser's Ganglion><Gasserian Ganglion><Goals><Growth and Development><Growth and Development function><Histology><Human><Infantile Autism><Integrins><Integrins Extracellular Matrix><Intercalary Neuron><Intercalated Neurons><Interneurons><Internuncial Cell><Internuncial Neuron><Intervention><Intervention Strategies><Intracellular Communication and Signaling><KO mice><Kanner's Syndrome><Knock-out><Knock-out Mice><Knockout><Knockout Mice><Knowledge><Ligands><Link><LoxP-flanked allele><Measurement><Mediating><Membrane><Membrane Protein Gene><Membrane Proteins><Membrane-Associated Proteins><Mice><Mice Mammals><Modern Man><Molecular><Molecular Interaction><Morphology><Murine><Mus><Mutant Strains Mice><N-Ethyl-N-nitrosourea><N-ethyl-N-nitroso-urea><Natural regeneration><Neonatal><Nerve Cells><Nerve Unit><Nervous System><Neural Cell><Neural Crest Cell><Neural Transmission><Neurocyte><Neurologic Body System><Neurologic Organ System><Neurons><Nitrosoethylurea><Null Mouse><Osteoblasts><Osteogenesis><Outcome><Output><PRO2286><Parietal Bone><Parietal bone structure><Parvalbumins><Pathogenesis><Patients><Phosphorylation><Process><Property><Protein Phosphorylation><Proteins><Receptor Protein><Regeneration><Role><Semilunar Ganglion><Sensory Ganglia><Signal Transduction><Signal Transduction Systems><Signaling><Skeletal Development><Skeletal system><Specific qualifier value><Specified><Structure of trigeminal ganglion><Surface Proteins><Synaptic Transmission><Testing><Therapeutic><Tissue Distribution><Tissues><Transgenic Organisms><Translating><Transmission><Trigeminal Ganglias><Trigeminal Ganglion><WNT Signaling Pathway><WNT signaling><Wild Type Mouse><X-ray microtomography><Xray microtomography><adulthood><autism spectral disorder><autism spectrum disorder><autistic spectrum disorder><behavioral assessment><beta catenin><biological signal transduction><bone><bone healing><bone repair><bone tissue formation><bone wound healing><brain tissue><calvarial><comparative><craniofacial><craniofacial bone><craniofacies><developmental><floxed><floxed allele><gamma-Aminobutyric Acid><gamma-Aminobutyric Acid Agonists><glycogen synthase kinase 3 beta><glycogen synthase kinase 3β><healing><improved><inhibitor><interventional strategy><member><membrane structure><micro CT><micro computed tomography><microCT><microtomography><mouse mutant><neural><neurological pathology><neuronal><new drug treatments><new drugs><new pharmacological therapeutic><new therapeutics><new therapy><next generation therapeutics><novel><novel drug treatments><novel drugs><novel pharmaco-therapeutic><novel pharmacological therapeutic><novel therapeutics><novel therapy><osseous wound healing><osteogenic><osteogenic protein><overexpress><overexpression><postnatal><premature><prematurity><presynaptic><receptor><regenerate><regenerate bone><repair><repaired><skeletal><skeletal tissue><social role><spatiotemporal><suture fusion><transgenic><transmission process><wildtype mouse><β-catenin><γ-Aminobutyric Acid>