From: Autism-associated CHD8 deficiency impairs axon development and migration of cortical neurons
Reference(s) | Endogenous CHD8 expression data relating to the current study | Model system(s) and method(s) used for disrupting CHD8 expression | Findings caused by disrupting CHD8 expression relating to the current study |
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Current study | ● Human (Brodmann region 19): CHD8 expressed in astrocytes (GFAP+) and in neurons (MAP2+, PV+, DCX+) by immunohistochemical stains ● Mice (whole brain lysates): CHD8 expression peaks at E16-E18, decreases substantially postnatally by qPCR and western blotting ● Mice (P3 brain sections and cultured neurons): CHD8 expression shows nuclear localization in MAP2+ neurons by immunostaining ● Mice (cultured neurons and glia): CHD8 is expressed in cultured neurons and to a lesser extent in cultured glia by western blotting | ● Mice (in vitro)—cultured neurons transfected with Chd8 shRNA constructs ● Mice (in vivo)—in utero electroporation at E14.5 with Chd8 shRNA constructs | ● Decreased axon length (both in vitro and in vivo) ● Reduced dendritic complexity (both in vitro and in vivo) ● Delayed neuronal migration (higher percentage of GFP+ cells in VZ/SVZ instead of CP) at E18.5 (in vivo), which normalized by P3 |
Durak et al. [18] | Mice (brain lysates): expression peaks at E12, then decreases during embryonic development to P2 by qPCR Human (DFC and MFC): expression peaks during early-mid fetal development and decreases from late fetal development to childhood by qPCR | Mice—in utero electroporation at E13 (for neuronal proliferation/migration studies) or E15 (for dendritic arborization studies) with Chd8 shRNA constructs | ● Increased neuronal migration (more GFP+ cells in CP instead of VZ/SVZ) at E16, accompanied by reduced proliferation, increased cell cycle exit, reduced mitotic activity, and premature Tuj1 expression ● Decreased dendritic arborization in upper cortical neurons from 5-month-old mice ● CHD8 mediates cortical neurogenesis via transcriptional regulation of cell cycle and Wnt signaling |
Mice (whole embryos): CHD8 was expressed in ES cells (~E3.5), E8.5 embryos, E12.5 embryos, E16.5 embryos, and to a lesser extent in newborn pups by western blotting | Mice—two lines of germline haploinsufficient mice were generated (replacing 9 exons with loxP-neo cassette, or ∆exons 11–13, disrupting only the long protein isoform) | ● Homozygous mutants show massive apoptosis at E7.5 and lethality ● At E14.5, haploinsufficient mice showed increased expression of early-fetal genes and decreased expression of mid-fetal genes | |
Platt et al. [22] | Mice (whole brains): expression profile from E10-P0, adult. Expression is highest at E10 and decreases over development by western blotting Mice (adult brain sections, somatosensory cortex): CHD8 shows nuclear localization and co-expresses with NeuN, PV, CNP1, and GFAP by immunostaining | Mice—germline haploinsufficient mice were generated by CRISPR/Cas9 introducing a 7 nucleotide deletion in exon 1, which disrupted the expression of both CHD8 isoforms | ● Normal lamination and specification of neuronal cell types at P21 ● No difference in number of cortical progenitor cells or cell cycle length at E15.5 |
Zhao et al. [25] | Mice (P14 white matter tracts): CHD8 is expressed in oligodendrocytes and to a lesser extent in GFAP+ astrocytes by immunostaining Human (cerebellum): CHD8 expression in Sox10+ oligodendrocytes by immunostaining Mice (P14 cortical sections): CHD8 is expressed in NeuN+ neurons but not clearly in GFAP+ astroctyes or Iba1+ microglia by immunostaining | Conditional Chd8 knockout mice (loxP sites surrounding exon 4) crossed with oligodendrocyte-specific Cre line | ● Homozygous conditional knockout mice show lethality by P21 and myelination defects ● Homozygous conditional knockout mice show reduced proliferation of oligodendrocyte precursor cells in P1 spinal cord ● Dual requirement of CHD8 for chromatin landscape establishment and histone methyltransferase recruitment to promote CNS myelination and repair |
Gompers et al. [35] | Expression analysis was not reported for different cell types or developmental time points | Mice—germline Chd8 haploinsufficient mice were generated (deletion of exon 5) | ● Increased proliferation of neuronal progenitors at E14.5 ● No gross lamination errors by P0 and P7 |
Wang et al. [36] CRISPR/Cas9-mediated heterozygous knockout of the autism gene CHD8 and characterization of its transcriptional networks in neurodevelopment | N/A | CRISPR/Cas9-mediated heterozygous knockout of CHD8 in iPSCs | ● Genes involved in cell cycle, neuronal differentiation, and in neuronal projection development are dysregulated |
Suetterlin et al. [23] | N/A | Chd8+/− mice (loxP sites on exon 3) crossed β-actinCre line | ● Chd8 heterozygous mice display increased total brain volume and showed volumetric increased of several brain regions, including cortical areas, hippocampus and parts of the cerebellum by high-solution MRI ● CHD8 controls the expression of ASD-associated axon guidance genes in the early postnatal neocortex |
Jung et al. [24] | In both males and females, CHD8 protein was more abundant in the brain relative to other tissues, at embryonic stages relative to postnatal stages, and in non-crude synaptosomal fractions | Chd8+/N2373 K mice carrying a heterozygous Chd8 frame-shift mutation | ● Distinct c-fos signals in male and female Chd8+/N2373K brains under baseline and maternal-separation conditions ● Opposite changes in inhibitory synaptic transmission in the male and female Chd8+/N2373K hippocampus |