bioRxiv ScienceSearch

Biology subjects

Lowry, W. E.

Publications and source records attributed to Lowry, W. E..

3 recordsLinked to original sources

A single cell transcriptomic analysis of human neocortical development

Defining the number, proportion, or lineage of distinct cell types in the developing human brain is an important goal of modern brain research. We defined single cell transcriptomic profiles for 40,000 cells at mid-gestation to identify cell types in the developing human neocortex. We define expression profiles corresponding to all known major cell types at this developmental period and identify multiple transcription factors and co-factors expressed in specific cell types, providing an unprecedented resource for understanding human neocortical development including the first single-cell characterization of human subplate neurons. We characterize major developmental trajectories during early neurogenesis, showing that cell type differentiation occurs on a continuum that involves transitions that tie cell cycle progression with early cell fate decisions. We use these data to deconvolute regulatory networks and map neuropsychiatric disease genes to specific cell types, implicating dysregulation of specific cell types, as the mechanistic underpinnings of several neurodevelopmental disorders. Together these results provide an extensive catalog of cell types in human neocortex and extend our understanding of early cortical development, human brain evolution and the cellular basis of neuropsychiatric disease.\n\nOne Sentence SummaryComprehensive single cell transcriptomes in developing human cortex inform models of cell diversity, differentiation and disease risk.

neuroscience

TDG Regulates Cell Cycle Progression In Human Neural Progenitors

As cells divide, they must replicate both their DNA and generate a new set of histone proteins. The newly synthesized daughter strands and histones are unmodified and must therefore be covalently modified to allow for transmission of important epigenetic marks to daughter cells. Human pluripotent stem cells (hPSCs) display a unique cell cycle profile, and control of the cell cycle is known to be critical for their proper differentiation and survival. A major unresolved question is how hPSCs regulate their DNA methylation status through the cell cycle, namely how passive and active demethylation work to maintain a stable genome. TDG, an embryonic essential gene, has been recently implicated as a major enzyme involved in demethylation1. Here we present new data showing that TDG regulates cell cycle related gene expression in human neural progenitors (NPCs) derived from hPSCs and controls their capacity for neural differentiation. These observations suggest that TDG and active demethylation play an important role in hPSC cell cycle regulation and differentiation.

molecular biology

Loss of MECP2 leads to telomere dysfunction and neuronal stress

To determine the role for mutations of MECP2 in Rett Syndrome, we generated isogenic lines of human iPSCs (hiPSCs), neural progenitor cells (NPCs), and neurons from patient fibroblasts with and without MECP2 expression in an attempt to recapitulate disease phenotypes in vitro. Molecular profiling uncovered neuronal specific gene expression changes including induction of a Senescence Associated Secretory Phenotype (SASP) program. Patient derived Neurons made without MECP2 show signs of stress, including induction of p53, and senescence. The induction of p53 appeared to affect dendritic branching in Rett neurons, as p53 inhibition restored dendritic complexity. These disease-in-a-dish data suggest that loss of MECP2 can lead to dendritic defects due to an increase in aspects of neuronal aging.

developmental biology