Biology subjects

Barrows, C.

Publications and source records attributed to Barrows, C..

4 recordsLinked to original sources

bioRxiv2025

A phenotypic brain organoid atlas for neurodevelopmental disorders

Thousands of genes are associated with neurodevelopmental disorders (NDDs), yet mechanisms and targeted treatments remain elusive. To fill these gaps, we present a CIRM-initiated NDD biobank of 352 publicly-available genetically-diverse patient-derived iPSCs, along with clinical details, brain imaging and genomic data, representing four major categories of disease: microcephaly (MIC), polymicrogyria (PMG), epilepsy (EPI), and intellectual disability (ID). From 35 representative patients, we studied over 6000 brain organoids for histology and single cell transcriptomics. Compared with an organoid library from ten neurotypicals, patients showed distinct cellular defects linked to underlying clinical disease categories. MIC showed defects in cell survival and excessive TTR+ cells, PMG showed intermediate progenitor cell junction defects, EPI showed excessive astrogliosis, and ID showed excessive generation of TTR+ cells. Our organoid atlas demonstrates both conserved and divergent NDD category-specific phenotypes, bridging genotype and phenotype. This NDD iPSC biobank can support future disease modeling and therapeutic approaches. HIGHLIGHTSO_LIResource of 352 CIRM-funded genetically-diverse IPSC lines from patients with neurodevelopmental disorders (NDDs). C_LIO_LIGenome/exome and brain images available for these genetically-diverse IPSC lines. C_LIO_LIDerived human brain organoids (hBOs) show disease-specific histological and cellular phenotypes. C_LIO_LIhBO phenotypes show unanticipated differentiation towards non-neuronal cell fates in NDDs. C_LI

neuroscience↗

bioRxiv2024

Genomic mosaicism reveals developmental organization of trunk neural crest-derived ganglia

The neural crest generates numerous cell types, but conflicting results leave developmental origins unresolved. Here using somatic mosaic variants as cellular barcodes, we infer embryonic clonal dynamics of trunk neural crest, focusing on the sensory and sympathetic ganglia. From three independent adult neurotypical human donors, we identified 1,278 mosaic variants using deep whole-genome sequencing, then profiled allelic fractions in 187 anatomically dissected ganglia. We found a massive rostrocaudal spread of progenitor clones specific to sensory or sympathetic ganglia, which unlike in the brain, showed robust bilateral distributions. Computational modeling suggested neural crest progenitor fate specification preceded delamination from neural tube. Single-cell multiomic analysis suggested both neurons and glia contributed to the rostrocaudal clonal organization. CRISPR barcoding in mice and live imaging in quail embryos confirmed these clonal dynamics across multiple somite levels. Our findings reveal an evolutionarily conserved clonal spread of cells populating peripheral neural ganglia. Highlights- Genetic mosaicism and real-time imaging reveal trunk neural crest cellular dynamics. - DRG or SG cells from different axial levels are more lineage-related than from the same level. - Cell fate specification of trunk neural crest progenitors occurs before neural tube delamination. - These aspects of clonal organization are evolutionarily conserved across mammals and avians.

developmental biology↗

bioRxiv2023

Cell-type-resolved somatic mosaicism reveals clonal dynamics of the human forebrain

Debate remains around anatomic origins of specific brain cell subtypes and lineage relationships within the human forebrain. Thus, direct observation in the mature human brain is critical for a complete understanding of the structural organization and cellular origins. Here, we utilize brain mosaic variation within specific cell types as distinct indicators for clonal dynamics, denoted as cell-type-specific Mosaic Variant Barcode Analysis. From four hemispheres from two different human neurotypical donors, we identified 287 and 780 mosaic variants (MVs), respectively that were used to deconvolve clonal dynamics. Clonal spread and allelic fractions within the brain reveal that local hippocampal excitatory neurons are more lineage-restricted compared with resident neocortical excitatory neurons or resident basal ganglia GABAergic inhibitory neurons. Furthermore, simultaneous genome-transcriptome analysis at both a cell-type-specific and single-cell level suggests a dorsal neocortical origin for a subgroup of DLX1+ inhibitory neurons that disperse radially from an origin shared with excitatory neurons. Finally, the distribution of MVs across 17 locations within one parietal lobe reveals restrictions of clonal spread in the anterior-posterior axis precedes that of the dorsal-ventral axis for both excitatory and inhibitory neurons. Thus cell-type resolved somatic mosaicism can uncover lineage relationships governing the development of the human forebrain.

neuroscience↗

bioRxiv2022

Comprehensive multiomic profiling of somatic mutations in malformations of cortical development

Malformations of cortical development (MCD) are neurological conditions displaying focal disruption of cortical architecture and cellular organization arising during embryogenesis, largely from somatic mosaic mutations. Identifying the genetic causes of MCD has been a challenge, as mutations remain at low allelic fractions in brain tissue resected to treat epilepsy. Here, we report a genetic atlas from 317 brain resections, identifying 69 mutated genes through intensive profiling of somatic mutations, combining whole-exome and targeted-amplicon sequencing with functional validation and single-cell sequencing. Genotype-phenotype correlation analysis elucidated specific MCD gene sets associating distinct pathophysiological and clinical phenotypes. The unique spatiotemporal expression patterns identified by comparing single-nucleus transcriptional sequences of mutated genes in control and patient brains implicate critical roles in excitatory neurogenic pools during brain development, and in promoting neuronal hyperexcitability after birth.

genetics↗