Biology subjects

Liu, C. S.

Publications and source records attributed to Liu, C. S..

3 recordsLinked to original sources

bioRxiv2025

Single-cell multiomic human brain atlas reveals regulatory drivers of cortical regionality

Distinct regional functionality of the human cortex is orchestrated by diverse cellular and molecular processes, yet the underlying regulatory mechanisms remain poorly understood. We performed multiomic single-cell and spatial characterization of nine regions of the human cortex to define the gene regulatory networks and transcription factors that govern cell-type and region specificity. With the combined data of over three million cells, two striking patterns of cortical neuron specialization were uncovered: a rostral-caudal gradient of calcium regulatory machinery, and subunit switching of multiple signaling receptor families across the transmodal-sensory axis. Gene regulatory network analysis revealed putative transcriptional regulators of cortical neuron specialization with cell-type- and region-specific gene regulation patterns. While regionalization was observed in gene expression, chromatin accessibility, and spatial distributions, these modalities exhibited distinct cortical patterns. Our findings illuminate critical neuronal pathways that vary throughout the cortex and the gene regulatory networks that establish cortical regionalization in the human brain.

neuroscience↗

bioRxiv2020

Evolution of cellular diversity in primary motor cortex of human, marmoset monkey, and mouse

The primary motor cortex (M1) is essential for voluntary fine motor control and is functionally conserved across mammals. Using high-throughput transcriptomic and epigenomic profiling of over 450,000 single nuclei in human, marmoset monkey, and mouse, we demonstrate a broadly conserved cellular makeup of this region, whose similarity mirrors evolutionary distance and is consistent between the transcriptome and epigenome. The core conserved molecular identity of neuronal and non-neuronal types allowed the generation of a cross-species consensus cell type classification and inference of conserved cell type properties across species. Despite overall conservation, many species specializations were apparent, including differences in cell type proportions, gene expression, DNA methylation, and chromatin state. Few cell type marker genes were conserved across species, providing a short list of candidate genes and regulatory mechanisms responsible for conserved features of homologous cell types, such as the GABAergic chandelier cells. This consensus transcriptomic classification allowed the Patch-seq identification of layer 5 (L5) corticospinal Betz cells in non-human primate and human and characterization of their highly specialized physiology and anatomy. These findings highlight the robust molecular underpinnings of cell type diversity in M1 across mammals and point to the genes and regulatory pathways responsible for the functional identity of cell types and their species-specific adaptations.

neuroscience↗

bioRxiv2019

Reply: Evidence that APP gene copy number changes reflect recombinant vector contamination

In the accompanying comment1, Kim et al. concluded that somatic gene recombination (SGR) and amyloid precursor protein (APP) genomic complementary DNAs (gencDNAs) in brain are contamination artifacts and do not naturally exist. We disagree. Here we address the three types of analyses used by Kim et al. to reach their conclusions: informatic contaminant identification, plasmid PCR, and single-cell sequencing. Additionally, Kim et al. requested "reads supporting novel APP insertion breakpoints," and we now provide 10 different examples that support APP gencDNA insertion within eight chromosomes beyond wildtype APP on chromosome 21 from Alzheimers disease (AD) samples. If SGR exists as experimentally supported here and previously2,3, contamination scenarios become moot. Our informatic analyses of data generated by an independent laboratory (Park et al.)4, complement and are entirely consistent with what Lee et al.2 presented via nine distinct lines of evidence, in addition to three from a prior publication3. Plasmid contamination was identified in a single pull-down dataset after publication of Lee et al.2; however subsequent analyses did not alter any of our conclusions including those of our prior publications3,5 and plasmid contamination-free replication of this approach by ourselves and others supported the original conclusions. Novel retro-insertion sites, alterations of APP gencDNA number and form with cell type from the same brain and pathogenic SNVs occurring only in AD, all support the existence of APP gencDNAs produced by SGR.

genomics↗