Publications by authors named "Ryan A Szeto"

The mammalian cerebral cortex shows functional specialization into regions with distinct neuronal compositions, most strikingly in the human brain, but little is known in about how cellular lineages shape cortical regional variation and neuronal cell types during development. Here, we use somatic single nucleotide variants (sSNVs) to map lineages of neuronal sub-types and cortical regions. Early-occurring sSNVs rarely respect Brodmann area (BA) borders, while late-occurring sSNVs mark neuron-generating clones with modest regional restriction, though descendants often dispersed into neighboring BAs.

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Article Synopsis
  • Prenatal alcohol exposure is the leading preventable cause of intellectual disabilities, resulting in Fetal Alcohol Spectrum Disorders (FASD).
  • Researchers studied how alcohol affects the human fetal cerebral cortex using cortical organoids and primary fetal neurons, revealing cellular effects on growth, cell cycles, and cell death.
  • The study identified molecular changes due to alcohol that disrupts neural signaling and development, impacting key processes like synapse formation, and confirmed these findings through advanced physiological recordings.
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The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19), which was rapidly declared a pandemic by the World Health Organization (WHO). Early clinical symptomatology focused mainly on respiratory illnesses. However, a variety of neurological manifestations in both adults and newborns are now well-documented.

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Transcription Factor 4 (TCF4) has been associated with autism, schizophrenia, and other neuropsychiatric disorders. However, how pathological TCF4 mutations affect the human neural tissue is poorly understood. Here, we derive neural progenitor cells, neurons, and brain organoids from skin fibroblasts obtained from children with Pitt-Hopkins Syndrome carrying clinically relevant mutations in TCF4.

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Maricic . performed an undisclosed in silico–only whole-exome sequencing analysis of our data and found genomic alterations previously undetected in some clones. Some of the predicted alterations, if true, could change the original genotype of the clones.

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Article Synopsis
  • The protein-coding gene neuro-oncological ventral antigen 1 (NOVA1) is crucial for brain development and differs between modern humans and our extinct relatives, the Neanderthals and Denisovans.
  • Researchers used genome editing to introduce an ancient version of this gene into modern human cells and studied its effects on brain organoids.
  • The archaic version of NOVA1 slowed neural development and changed the complexity and electrical properties of the organoids, suggesting that human-specific changes to this gene may have influenced our evolution.
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The human transcription factor 4 gene (TCF4) encodes a helix-loop-helix transcription factor widely expressed throughout the body and during neural development. Mutations in TCF4 cause a devastating autism spectrum disorder known as Pitt-Hopkins syndrome, characterized by a range of aberrant phenotypes including severe intellectual disability, absence of speech, delayed cognitive and motor development, and dysmorphic features. Moreover, polymorphisms in TCF4 have been associated with schizophrenia and other psychiatric and neurological conditions.

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Gene expression comprises a diverse array of enzymes, proteins, non-coding transcripts, and cellular structures to guide the transfer of genetic information to its various final products. In the brain, the coordination among genes, or lack thereof, characterizes individual brain regions, mediates a variety of brain-related disorders, and brings light to fundamental differences between species. RNA processing, occurring between transcription and translation, controls an essential portion of gene expression through splicing, editing, localization, stability, and interference.

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