publications | Hanqing Liu

2023

Single-cell DNA methylome and 3D multi-omic atlas of the adult mouse brain

Hanqing Liu*, Qiurui Zeng*, Jingtian Zhou, Anna Bartlett, Bang-An Wang, Peter Berube, Wei Tian, Mia Kenworthy, Jordan Altshul, Joseph R Nery, Huaming Chen, Rosa G Castanon, Songpeng Zu, Yang Eric Li, Jacinta Lucero, Julia K Osteen, Antonio Pinto-Duarte, Jasper Lee, Jon Rink, Silvia Cho, Nora Emerson, Michael Nunn, Carolyn O’Connor, Zhanghao Wu, Ion Stoica, Zizhen Yao, Kimberly A Smith, Bosiljka Tasic, Chongyuan Luo, Jesse R Dixon, Hongkui Zeng, Bing Ren, M Margarita Behrens, and Joseph R Ecker

Nature, Dec 2023

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Cytosine DNA methylation is essential in brain development and is implicated in various neurological disorders. Understanding DNA methylation diversity across the entire brain in a spatial context is fundamental for a complete molecular atlas of brain cell types and their gene regulatory landscapes. Here we used single-nucleus methylome sequencing (snmC-seq3) and multi-omic sequencing (snm3C-seq)1 technologies to generate 301,626 methylomes and 176,003 chromatin conformation–methylome joint profiles from 117 dissected regions throughout the adult mouse brain. Using iterative clustering and integrating with companion whole-brain transcriptome and chromatin accessibility datasets, we constructed a methylation-based cell taxonomy with 4,673 cell groups and 274 cross-modality-annotated subclasses. We identified 2.6 million differentially methylated regions across the genome that represent potential gene regulation elements. Notably, we observed spatial cytosine methylation patterns on both genes and regulatory elements in cell types within and across brain regions. Brain-wide spatial transcriptomics data validated the association of spatial epigenetic diversity with transcription and improved the anatomical mapping of our epigenetic datasets. Furthermore, chromatin conformation diversities occurred in important neuronal genes and were highly associated with DNA methylation and transcription changes. Brain-wide cell-type comparisons enabled the construction of regulatory networks that incorporate transcription factors, regulatory elements and their potential downstream gene targets. Finally, intragenic DNA methylation and chromatin conformation patterns predicted alternative gene isoform expression observed in a whole-brain SMART-seq2 dataset. Our study establishes a brain-wide, single-cell DNA methylome and 3D multi-omic atlas and provides a valuable resource for comprehending the cellular–spatial and regulatory genome diversity of the mouse brain. Methylome-based clustering and cross-modality integration with companion datasets from the BRAIN Initiative Cell Census Network enabled the construction of a 3D multi-omic genome atlas of the adult mouse brain featuring thousands of cell-type-specific profiles.
Single-cell analysis of chromatin accessibility in the adult mouse brain

Songpeng Zu, Yang Eric Li, Kangli Wang, Ethan J Armand, Sainath Mamde, Maria Luisa Amaral, Yuelai Wang, Andre Chu, Yang Xie, Michael Miller, Jie Xu, Zhaoning Wang, Kai Zhang, Bojing Jia, Xiaomeng Hou, Lin Lin, Qian Yang, Seoyeon Lee, Bin Li, Samantha Kuan, Hanqing Liu, Jingtian Zhou, Antonio Pinto-Duarte, Jacinta Lucero, Julia Osteen, Michael Nunn, Kimberly A Smith, Bosiljka Tasic, Zizhen Yao, Hongkui Zeng, Zihan Wang, Jingbo Shang, M Margarita Behrens, Joseph R Ecker, Allen Wang, Sebastian Preissl, and Bing Ren

Nature, Dec 2023

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Recent advances in single-cell technologies have led to the discovery of thousands of brain cell types; however, our understanding of the gene regulatory programs in these cell types is far from complete1–4. Here we report a comprehensive atlas of candidate cis-regulatory DNA elements (cCREs) in the adult mouse brain, generated by analysing chromatin accessibility in 2.3 million individual brain cells from 117 anatomical dissections. The atlas includes approximately 1 million cCREs and their chromatin accessibility across 1,482 distinct brain cell populations, adding over 446,000 cCREs to the most recent such annotation in the mouse genome. The mouse brain cCREs are moderately conserved in the human brain. The mouse-specific cCREs—specifically, those identified from a subset of cortical excitatory neurons—are strongly enriched for transposable elements, suggesting a potential role for transposable elements in the emergence of new regulatory programs and neuronal diversity. Finally, we infer the gene regulatory networks in over 260 subclasses of mouse brain cells and develop deep-learning models to predict the activities of gene regulatory elements in different brain cell types from the DNA sequence alone. Our results provide a resource for the analysis of cell-type-specific gene regulation programs in both mouse and human brains. An atlas of candidate cis-regulatory DNA elements (cCREs) in the adult mouse brain unravels the transcriptional regulatory programs that drive the heterogeneity and complexity of brain structure and function.
Brain-wide correspondence of neuronal epigenomics and distant projections

Jingtian Zhou, Zhuzhu Zhang, May Wu, Hanqing Liu, Yan Pang, Anna Bartlett, Zihao Peng, Wubin Ding, Angeline Rivkin, Will N Lagos, Elora Williams, Cheng-Ta Lee, Paula Assakura Miyazaki, Andrew Aldridge, Qiurui Zeng, J L Angelo Salinda, Naomi Claffey, Michelle Liem, Conor Fitzpatrick, Lara Boggeman, Zizhen Yao, Kimberly A Smith, Bosiljka Tasic, Jordan Altshul, Mia A Kenworthy, Cynthia Valadon, Joseph R Nery, Rosa G Castanon, Neelakshi S Patne, Minh Vu, Mohammad Rashid, Matthew Jacobs, Tony Ito, Julia Osteen, Nora Emerson, Jasper Lee, Silvia Cho, Jon Rink, Hsiang-Hsuan Huang, António Pinto-Duartec, and 11 more authors

Nature, Dec 2023

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Single-cell analyses parse the brain’s billions of neurons into thousands of ‘cell-type’ clusters residing in different brain structures1. Many cell types mediate their functions through targeted long-distance projections allowing interactions between specific cell types. Here we used epi-retro-seq2 to link single-cell epigenomes and cell types to long-distance projections for 33,034 neurons dissected from 32 different regions projecting to 24 different targets (225 source-to-target combinations) across the whole mouse brain. We highlight uses of these data for interrogating principles relating projection types to transcriptomics and epigenomics, and for addressing hypotheses about cell types and connections related to genetics. We provide an overall synthesis with 926 statistical comparisons of discriminability of neurons projecting to each target for every source. We integrate this dataset into the larger BRAIN Initiative Cell Census Network atlas, composed of millions of neurons, to link projection cell types to consensus clusters. Integration with spatial transcriptomics further assigns projection-enriched clusters to smaller source regions than the original dissections. We exemplify this by presenting in-depth analyses of projection neurons from the hypothalamus, thalamus, hindbrain, amygdala and midbrain to provide insights into properties of those cell types, including differentially expressed genes, their associated cis-regulatory elements and transcription-factor-binding motifs, and neurotransmitter use. This study uses epi-retro-seq to link single-cell epigenomes and cell types to long-distance projections for neurons dissected from different regions projecting to different targets across the whole mouse brain.
Conserved and divergent gene regulatory programs of the mammalian neocortex

Nathan R Zemke, Ethan J Armand, Wenliang Wang, Seoyeon Lee, Jingtian Zhou, Yang Eric Li, Hanqing Liu, Wei Tian, Joseph R Nery, Rosa G Castanon, Anna Bartlett, Julia K Osteen, Daofeng Li, Xiaoyu Zhuo, Vincent Xu, Lei Chang, Keyi Dong, Hannah S Indralingam, Jonathan A Rink, Yang Xie, Michael Miller, Fenna M Krienen, Qiangge Zhang, Naz Taskin, Jonathan Ting, Guoping Feng, Steven A McCarroll, Edward M Callaway, Ting Wang, Ed S Lein, M Margarita Behrens, Joseph R Ecker, and Bing Ren

Nature, Dec 2023

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Divergence of cis-regulatory elements drives species-specific traits1, but how this manifests in the evolution of the neocortex at the molecular and cellular level remains unclear. Here we investigated the gene regulatory programs in the primary motor cortex of human, macaque, marmoset and mouse using single-cell multiomics assays, generating gene expression, chromatin accessibility, DNA methylome and chromosomal conformation profiles from a total of over 200,000 cells. From these data, we show evidence that divergence of transcription factor expression corresponds to species-specific epigenome landscapes. We find that conserved and divergent gene regulatory features are reflected in the evolution of the three-dimensional genome. Transposable elements contribute to nearly 80% of the human-specific candidate cis-regulatory elements in cortical cells. Through machine learning, we develop sequence-based predictors of candidate cis-regulatory elements in different species and demonstrate that the genomic regulatory syntax is highly preserved from rodents to primates. Finally, we show that epigenetic conservation combined with sequence similarity helps to uncover functional cis-regulatory elements and enhances our ability to interpret genetic variants contributing to neurological disease and traits. A single-cell multiomics analysis of over 200,000 cells of the primary motor cortex of human, macaque, marmoset and mouse shows that divergence of transcription factor expression corresponds to species-specific epigenome landscapes, and conserved and divergent gene regulatory features are reflected in the evolution of the three-dimensional genome.
Single-cell DNA methylation and 3D genome architecture in the human brain

Wei Tian, Jingtian Zhou, Anna Bartlett, Qiurui Zeng, Hanqing Liu, Rosa G Castanon, Mia Kenworthy, Jordan Altshul, Cynthia Valadon, Andrew Aldridge, Joseph R Nery, Huaming Chen, Jiaying Xu, Nicholas D Johnson, Jacinta Lucero, Julia K Osteen, Nora Emerson, Jon Rink, Jasper Lee, Yang E Li, Kimberly Siletti, Michelle Liem, Naomi Claffey, Carolyn O’Connor, Anna Marie Yanny, Julie Nyhus, Nick Dee, Tamara Casper, Nadiya Shapovalova, Daniel Hirschstein, Song-Lin Ding, Rebecca Hodge, Boaz P Levi, C Dirk Keene, Sten Linnarsson, Ed Lein, Bing Ren, M Margarita Behrens, and Joseph R Ecker

Science, Oct 2023

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Delineating the gene-regulatory programs underlying complex cell types is fundamental for understanding brain function in health and disease. Here, we comprehensively examined human brain cell epigenomes by probing DNA methylation and chromatin conformation at single-cell resolution in 517 thousand cells (399 thousand neurons and 118 thousand non-neurons) from 46 regions of three adult male brains. We identified 188 cell types and characterized their molecular signatures. Integrative analyses revealed concordant changes in DNA methylation, chromatin accessibility, chromatin organization, and gene expression across cell types, cortical areas, and basal ganglia structures. We further developed single-cell methylation barcodes that reliably predict brain cell types using the methylation status of select genomic sites. This multimodal epigenomic brain cell atlas provides new insights into the complexity of cell-type-specific gene regulation in adult human brains.
A guide to the BRAIN Initiative Cell Census Network data ecosystem

Michael Hawrylycz, Maryann E Martone, Giorgio A Ascoli, Jan G Bjaalie, Hong-Wei Dong, Satrajit S Ghosh, Jesse Gillis, Ronna Hertzano, David R Haynor, Patrick R Hof, Yongsoo Kim, Ed Lein, Yufeng Liu, Jeremy A Miller, Partha P Mitra, Eran Mukamel, Lydia Ng, David Osumi-Sutherland, Hanchuan Peng, Patrick L Ray, Raymond Sanchez, Aviv Regev, Alex Ropelewski, Richard H Scheuermann, Shawn Zheng Kai Tan, Carol L Thompson, Timothy Tickle, Hagen Tilgner, Merina Varghese, Brock Wester, Owen White, Hongkui Zeng, Brian Aevermann, David Allemang, Seth Ament, Thomas L Athey, Cody Baker, Katherine S Baker, Pamela M Baker, Anita Bandrowski, and 63 more authors

PLoS Biol., Jun 2023

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Characterizing cellular diversity at different levels of biological organization and across data modalities is a prerequisite to understanding the function of cell types in the brain. Classification of neurons is also essential to manipulate cell types in controlled ways and to understand their variation and vulnerability in brain disorders. The BRAIN Initiative Cell Census Network (BICCN) is an integrated network of data-generating centers, data archives, and data standards developers, with the goal of systematic multimodal brain cell type profiling and characterization. Emphasis of the BICCN is on the whole mouse brain with demonstration of prototype feasibility for human and nonhuman primate (NHP) brains. Here, we provide a guide to the cellular and spatial approaches employed by the BICCN, and to accessing and using these data and extensive resources, including the BRAIN Cell Data Center (BCDC), which serves to manage and integrate data across the ecosystem. We illustrate the power of the BICCN data ecosystem through vignettes highlighting several BICCN analysis and visualization tools. Finally, we present emerging standards that have been developed or adopted toward Findable, Accessible, Interoperable, and Reusable (FAIR) neuroscience. The combined BICCN ecosystem provides a comprehensive resource for the exploration and analysis of cell types in the brain.
Robust enhancer-gene regulation identified by single-cell transcriptomes and epigenomes

Fangming Xie, Ethan J Armand, Zizhen Yao, Hanqing Liu, Anna Bartlett, M Margarita Behrens, Yang Eric Li, Jacinta D Lucero, Chongyuan Luo, Joseph R Nery, Antonio Pinto-Duarte, Olivier B Poirion, Sebastian Preissl, Angeline C Rivkin, Bosiljka Tasic, Hongkui Zeng, Bing Ren, Joseph R Ecker, and Eran A Mukamel

Cell Genomics, Jun 2023

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Summary Single-cell sequencing could help to solve the fundamental challenge of linking millions of cell-type-specific enhancers with their target genes. However, this task is confounded by patterns of gene co-expression in much the same way that genetic correlation due to linkage disequilibrium confounds fine-mapping in genome-wide association studies (GWAS). We developed a non-parametric permutation-based procedure to establish stringent statistical criteria to control the risk of false-positive associations in enhancer-gene association studies (EGAS). We applied our procedure to large-scale transcriptome and epigenome data from multiple tissues and species, including the mouse and human brain, to predict enhancer-gene associations genome wide. We tested the functional validity of our predictions by comparing them with chromatin conformation data and causal enhancer perturbation experiments. Our study shows how controlling for gene co-expression enables robust enhancer-gene linkage using single-cell sequencing data.

2022

Single nucleus multi-omics identifies human cortical cell regulatory genome diversity

Chongyuan Luo*, Hanqing Liu*, Fangming Xie*, Ethan J Armand, Kimberly Siletti, Trygve E Bakken, Rongxin Fang, Wayne I Doyle, Tim Stuart, Rebecca D Hodge, Lijuan Hu, Bang-An Wang, Zhuzhu Zhang, Sebastian Preissl, Dong-Sung Lee, Jingtian Zhou, Sheng-Yong Niu, Rosa Castanon, Anna Bartlett, Angeline Rivkin, Xinxin Wang, Jacinta Lucero, Joseph R Nery, David A Davis, Deborah C Mash, Rahul Satija, Jesse R Dixon, Sten Linnarsson, Ed Lein, M Margarita Behrens, Bing Ren, Eran A Mukamel, and Joseph R Ecker

Cell Genomics, Mar 2022

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SummarySingle-cell technologies measure unique cellular signatures but are typically limited to a single modality. Computational approaches allow the fusion of diverse single-cell data types, but their efficacy is difficult to validate in the absence of authentic multi-omic measurements. To comprehensively assess the molecular phenotypes of single cells, we devised single-nucleus methylcytosine, chromatin accessibility, and transcriptome sequencing (snmCAT-seq) and applied it to postmortem human frontal cortex tissue. We developed a cross-validation approach using multi-modal information to validate fine-grained cell types and assessed the effectiveness of computational data fusion methods. Correlation analysis in individual cells revealed distinct relations between methylation and gene expression. Our integrative approach enabled joint analyses of the methylome, transcriptome, chromatin accessibility, and conformation for 63 human cortical cell types. We reconstructed regulatory lineages for cortical cell populations and found specific enrichment of genetic risk for neuropsychiatric traits, enabling the prediction of cell types that are associated with diseases.

2021

Improved pathogenicity prediction for rare human missense variants

Yingzhou Wu, Hanqing Liu, Roujia Li, Song Sun, Jochen Weile, and Frederick P Roth

Am. J. Hum. Genet., Oct 2021

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The success of personalized genomic medicine depends on our ability to assess the pathogenicity of rare human variants, including the important class of missense variation. There are many challenges in training accurate computational systems, e.g., in finding the balance between quantity, quality, and bias in the variant sets used as training examples and avoiding predictive features that can accentuate the effects of bias. Here, we describe VARITY, which judiciously exploits a larger reservoir of training examples with uncertain accuracy and representativity. To limit circularity and bias, VARITY excludes features informed by variant annotation and protein identity. To provide a rationale for each prediction, we quantified the contribution of features and feature combinations to the pathogenicity inference of each variant. VARITY outperformed all previous computational methods evaluated, identifying at least 10% more pathogenic variants at thresholds achieving high (90% precision) stringency.
A multimodal cell census and atlas of the mammalian primary motor cortex

BRAIN Initiative Cell Census Network (BICCN)

Nature, Oct 2021

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Here we report the generation of a multimodal cell census and atlas of the mammalian primary motor cortex as the initial product of the BRAIN Initiative Cell Census Network (BICCN). This was achieved by coordinated large-scale analyses of single-cell transcriptomes, chromatin accessibility, DNA methylomes, spatially resolved single-cell transcriptomes, morphological and electrophysiological properties and cellular resolution input-output mapping, integrated through cross-modal computational analysis. Our results advance the collective knowledge and understanding of brain cell-type organization1-5. First, our study reveals a unified molecular genetic landscape of cortical cell types that integrates their transcriptome, open chromatin and DNA methylation maps. Second, cross-species analysis achieves a consensus taxonomy of transcriptomic types and their hierarchical organization that is conserved from mouse to marmoset and human. Third, in situ single-cell transcriptomics provides a spatially resolved cell-type atlas of the motor cortex. Fourth, cross-modal analysis provides compelling evidence for the transcriptomic, epigenomic and gene regulatory basis of neuronal phenotypes such as their physiological and anatomical properties, demonstrating the biological validity and genomic underpinning of neuron types. We further present an extensive genetic toolset for targeting glutamatergic neuron types towards linking their molecular and developmental identity to their circuit function. Together, our results establish a unifying and mechanistic framework of neuronal cell-type organization that integrates multi-layered molecular genetic and spatial information with multi-faceted phenotypic properties.
Epigenomic diversity of cortical projection neurons in the mouse brain

Zhuzhu Zhang, Jingtian Zhou, Pengcheng Tan, Yan Pang, Angeline C Rivkin, Megan A Kirchgessner, Elora Williams, Cheng-Ta Lee, Hanqing Liu, Alexis D Franklin, Paula Assakura Miyazaki, Anna Bartlett, Andrew I Aldridge, Minh Vu, Lara Boggeman, Conor Fitzpatrick, Joseph R Nery, Rosa G Castanon, Mohammad Rashid, Matthew W Jacobs, Tony Ito-Cole, Carolyn O’Connor, António Pinto-Duartec, Bertha Dominguez, Jared B Smith, Sheng-Yong Niu, Kuo-Fen Lee, Xin Jin, Eran A Mukamel, M Margarita Behrens, Joseph R Ecker, and Edward M Callaway

Nature, Oct 2021

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Neuronal cell types are classically defined by their molecular properties, anatomy and functions. Although recent advances in single-cell genomics have led to high-resolution molecular characterization of cell type diversity in the brain1, neuronal cell types are often studied out of the context of their anatomical properties. To improve our understanding of the relationship between molecular and anatomical features that define cortical neurons, here we combined retrograde labelling with single-nucleus DNA methylation sequencing to link neural epigenomic properties to projections. We examined 11,827 single neocortical neurons from 63 cortico-cortical and cortico-subcortical long-distance projections. Our results showed unique epigenetic signatures of projection neurons that correspond to their laminar and regional location and projection patterns. On the basis of their epigenomes, intra-telencephalic cells that project to different cortical targets could be further distinguished, and some layer 5 neurons that project to extra-telencephalic targets (L5 ET) formed separate clusters that aligned with their axonal projections. Such separation varied between cortical areas, which suggests that there are area-specific differences in L5 ET subtypes, which were further validated by anatomical studies. Notably, a population of cortico-cortical projection neurons clustered with L5 ET rather than intra-telencephalic neurons, which suggests that a population of L5 ET cortical neurons projects to both targets. We verified the existence of these neurons by dual retrograde labelling and anterograde tracing of cortico-cortical projection neurons, which revealed axon terminals in extra-telencephalic targets including the thalamus, superior colliculus and pons. These findings highlight the power of single-cell epigenomic approaches to connect the molecular properties of neurons with their anatomical and projection properties.
DNA methylation atlas of the mouse brain at single-cell resolution

Hanqing Liu*, Jingtian Zhou*, Wei Tian, Chongyuan Luo, Anna Bartlett, Andrew Aldridge, Jacinta Lucero, Julia K Osteen, Joseph R Nery, Huaming Chen, Angeline Rivkin, Rosa G Castanon, Ben Clock, Yang Eric Li, Xiaomeng Hou, Olivier B Poirion, Sebastian Preissl, Antonio Pinto-Duarte, Carolyn O’Connor, Lara Boggeman, Conor Fitzpatrick, Michael Nunn, Eran A Mukamel, Zhuzhu Zhang, Edward M Callaway, Bing Ren, Jesse R Dixon, M Margarita Behrens, and Joseph R Ecker

Nature, Oct 2021

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Mammalian brain cells show remarkable diversity in gene expression, anatomy and function, yet the regulatory DNA landscape underlying this extensive heterogeneity is poorly understood. Here we carry out a comprehensive assessment of the epigenomes of mouse brain cell types by applying single-nucleus DNA methylation sequencing1,2 to profile 103,982 nuclei (including 95,815 neurons and 8,167 non-neuronal cells) from 45 regions of the mouse cortex, hippocampus, striatum, pallidum and olfactory areas. We identified 161 cell clusters with distinct spatial locations and projection targets. We constructed taxonomies of these epigenetic types, annotated with signature genes, regulatory elements and transcription factors. These features indicate the potential regulatory landscape supporting the assignment of putative cell types and reveal repetitive usage of regulators in excitatory and inhibitory cells for determining subtypes. The DNA methylation landscape of excitatory neurons in the cortex and hippocampus varied continuously along spatial gradients. Using this deep dataset, we constructed an artificial neural network model that precisely predicts single neuron cell-type identity and brain area spatial location. Integration of high-resolution DNA methylomes with single-nucleus chromatin accessibility data3 enabled prediction of high-confidence enhancer-gene interactions for all identified cell types, which were subsequently validated by cell-type-specific chromatin conformation capture experiments4. By combining multi-omic datasets (DNA methylation, chromatin contacts, and open chromatin) from single nuclei and annotating the regulatory genome of hundreds of cell types in the mouse brain, our DNA methylation atlas establishes the epigenetic basis for neuronal diversity and spatial organization throughout the mouse cerebrum.
Comparative cellular analysis of motor cortex in human, marmoset and mouse

Trygve E Bakken, Nikolas L Jorstad, Qiwen Hu, Blue B Lake, Wei Tian, Brian E Kalmbach, Megan Crow, Rebecca D Hodge, Fenna M Krienen, Staci A Sorensen, Jeroen Eggermont, Zizhen Yao, Brian D Aevermann, Andrew I Aldridge, Anna Bartlett, Darren Bertagnolli, Tamara Casper, Rosa G Castanon, Kirsten Crichton, Tanya L Daigle, Rachel Dalley, Nick Dee, Nikolai Dembrow, Dinh Diep, Song-Lin Ding, Weixiu Dong, Rongxin Fang, Stephan Fischer, Melissa Goldman, Jeff Goldy, Lucas T Graybuck, Brian R Herb, Xiaomeng Hou, Jayaram Kancherla, Matthew Kroll, Kanan Lathia, Baldur Lew, Yang Eric Li, Christine S Liu, Hanqing Liu, and 66 more authors

Nature, Oct 2021

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The primary motor cortex (M1) is essential for voluntary fine-motor control and is functionally conserved across mammals1. Here, using high-throughput transcriptomic and epigenomic profiling of more than 450,000 single nuclei in humans, marmoset monkeys and mice, we demonstrate a broadly conserved cellular makeup of this region, with similarities that mirror evolutionary distance and are consistent between the transcriptome and epigenome. The core conserved molecular identities of neuronal and non-neuronal cell types allow us to generate a cross-species consensus classification of cell types, and to infer conserved properties of cell types across species. Despite the overall conservation, however, many species-dependent specializations are apparent, including differences in cell-type proportions, gene expression, DNA methylation and chromatin state. Few cell-type marker genes are conserved across species, revealing a short list of candidate genes and regulatory mechanisms that are responsible for conserved features of homologous cell types, such as the GABAergic chandelier cells. This consensus transcriptomic classification allows us to use patch-seq (a combination of whole-cell patch-clamp recordings, RNA sequencing and morphological characterization) to identify corticospinal Betz cells from layer 5 in non-human primates and humans, and to characterize 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.
A transcriptomic and epigenomic cell atlas of the mouse primary motor cortex

Zizhen Yao*, Hanqing Liu*, Fangming Xie*, Stephan Fischer*, Ricky S Adkins, Andrew I Aldridge, Seth A Ament, Anna Bartlett, M Margarita Behrens, Koen Berge, Darren Bertagnolli, Hector Roux Bézieux, Tommaso Biancalani, A Sina Booeshaghi, Héctor Corrada Bravo, Tamara Casper, Carlo Colantuoni, Jonathan Crabtree, Heather Creasy, Kirsten Crichton, Megan Crow, Nick Dee, Elizabeth L Dougherty, Wayne I Doyle, Sandrine Dudoit, Rongxin Fang, Victor Felix, Olivia Fong, Michelle Giglio, Jeff Goldy, Mike Hawrylycz, Brian R Herb, Ronna Hertzano, Xiaomeng Hou, Qiwen Hu, Jayaram Kancherla, Matthew Kroll, Kanan Lathia, Yang Eric Li, Jacinta D Lucero, and 43 more authors

Nature, Oct 2021

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Single-cell transcriptomics can provide quantitative molecular signatures for large, unbiased samples of the diverse cell types in the brain1-3. With the proliferation of multi-omics datasets, a major challenge is to validate and integrate results into a biological understanding of cell-type organization. Here we generated transcriptomes and epigenomes from more than 500,000 individual cells in the mouse primary motor cortex, a structure that has an evolutionarily conserved role in locomotion. We developed computational and statistical methods to integrate multimodal data and quantitatively validate cell-type reproducibility. The resulting reference atlas-containing over 56 neuronal cell types that are highly replicable across analysis methods, sequencing technologies and modalities-is a comprehensive molecular and genomic account of the diverse neuronal and non-neuronal cell types in the mouse primary motor cortex. The atlas includes a population of excitatory neurons that resemble pyramidal cells in layer 4 in other cortical regions4. We further discovered thousands of concordant marker genes and gene regulatory elements for these cell types. Our results highlight the complex molecular regulation of cell types in the brain and will directly enable the design of reagents to target specific cell types in the mouse primary motor cortex for functional analysis.
An atlas of gene regulatory elements in adult mouse cerebrum

Yang Eric Li, Sebastian Preissl, Xiaomeng Hou, Ziyang Zhang, Kai Zhang, Yunjiang Qiu, Olivier B Poirion, Bin Li, Joshua Chiou, Hanqing Liu, Antonio Pinto-Duarte, Naoki Kubo, Xiaoyu Yang, Rongxin Fang, Xinxin Wang, Jee Yun Han, Jacinta Lucero, Yiming Yan, Michael Miller, Samantha Kuan, David Gorkin, Kyle J Gaulton, Yin Shen, Michael Nunn, Eran A Mukamel, M Margarita Behrens, Joseph R Ecker, and Bing Ren

Nature, Oct 2021

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The mammalian cerebrum performs high-level sensory perception, motor control and cognitive functions through highly specialized cortical and subcortical structures1. Recent surveys of mouse and human brains with single-cell transcriptomics2-6 and high-throughput imaging technologies7,8 have uncovered hundreds of neural cell types distributed in different brain regions, but the transcriptional regulatory programs that are responsible for the unique identity and function of each cell type remain unknown. Here we probe the accessible chromatin in more than 800,000 individual nuclei from 45 regions that span the adult mouse isocortex, olfactory bulb, hippocampus and cerebral nuclei, and use the resulting data to map the state of 491,818 candidate cis-regulatory DNA elements in 160 distinct cell types. We find high specificity of spatial distribution for not only excitatory neurons, but also most classes of inhibitory neurons and a subset of glial cell types. We characterize the gene regulatory sequences associated with the regional specificity within these cell types. We further link a considerable fraction of the cis-regulatory elements to putative target genes expressed in diverse cerebral cell types and predict transcriptional regulators that are involved in a broad spectrum of molecular and cellular pathways in different neuronal and glial cell populations. Our results provide a foundation for comprehensive analysis of gene regulatory programs of the mammalian brain and assist in the interpretation of noncoding risk variants associated with various neurological diseases and traits in humans.
Activity-dependent modulation of synapse-regulating genes in astrocytes

Isabella Farhy-Tselnicker, Matthew M Boisvert, Hanqing Liu, Cari Dowling, Galina A Erikson, Elena Blanco-Suarez, Chen Farhy, Maxim N Shokhirev, Joseph R Ecker, and Nicola J Allen

Elife, Sep 2021

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Astrocytes regulate the formation and function of neuronal synapses via multiple signals; however, what controls regional and temporal expression of these signals during development is unknown. We determined the expression profile of astrocyte synapse-regulating genes in the developing mouse visual cortex, identifying astrocyte signals that show differential temporal and layer-enriched expression. These patterns are not intrinsic to astrocytes, but regulated by visually evoked neuronal activity, as they are absent in mice lacking glutamate release from thalamocortical terminals. Consequently, synapses remain immature. Expression of synapse-regulating genes and synaptic development is also altered when astrocyte signaling is blunted by diminishing calcium release from astrocyte stores. Single-nucleus RNA sequencing identified groups of astrocytic genes regulated by neuronal and astrocyte activity, and a cassette of genes that show layer-specific enrichment. Thus, the development of cortical circuits requires coordinated signaling between astrocytes and neurons, highlighting astrocytes as a target to manipulate in neurodevelopmental disorders.
Single nucleus multi-omics regulatory landscape of the murine pituitary

Frederique Ruf-Zamojski, Zidong Zhang, Michel Zamojski, Gregory R Smith, Natalia Mendelev, Hanqing Liu, German Nudelman, Mika Moriwaki, Hanna Pincas, Rosa Gomez Castanon, Venugopalan D Nair, Nitish Seenarine, Mary Anne S Amper, Xiang Zhou, Luisina Ongaro, Chirine Toufaily, Gauthier Schang, Joseph R Nery, Anna Bartlett, Andrew Aldridge, Nimisha Jain, Gwen V Childs, Olga G Troyanskaya, Joseph R Ecker, Judith L Turgeon, Corrine K Welt, Daniel J Bernard, and Stuart C Sealfon

Nat. Commun., May 2021

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To provide a multi-omics resource and investigate transcriptional regulatory mechanisms, we profile the transcriptome, chromatin accessibility, and methylation status of over 70,000 single nuclei (sn) from adult mouse pituitaries. Paired snRNAseq and snATACseq datasets from individual animals highlight a continuum between developmental epigenetically-encoded cell types and transcriptionally-determined transient cell states. Co-accessibility analysis-based identification of a putative Fshb cis-regulatory domain that overlaps the fertility-linked rs11031006 human polymorphism, followed by experimental validation illustrate the use of this resource for hypothesis generation. We also identify transcriptional and chromatin accessibility programs distinguishing each major cell type. Regulons, which are co-regulated gene sets sharing binding sites for a common transcription factor driver, recapitulate cell type clustering. We identify both cell type-specific and sex-specific regulons that are highly correlated with promoter accessibility, but not with methylation state, supporting the centrality of chromatin accessibility in shaping cell-defining transcriptional programs. The sn multi-omics atlas is accessible at snpituitaryatlas.princeton.edu.

2020

Mutations of MAP1B encoding a microtubule-associated phosphoprotein cause sensorineural hearing loss

Limei Cui, Jing Zheng, Qiong Zhao, Jia-Rong Chen, Hanqing Liu, Guanghua Peng, Yue Wu, Chao Chen, Qiufen He, Haosong Shi, Shankai Yin, Rick A Friedman, Ye Chen, and Min-Xin Guan

JCI Insight, Dec 2020

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The pathophysiology underlying spiral ganglion cell defect-induced deafness remains elusive. Using the whole exome sequencing approach, in combination with functional assays and a mouse disease model, we identified the potentially novel deafness-causative MAP1B gene encoding a highly conserved microtubule-associated protein. Three novel heterozygous MAP1B mutations (c.4198A>G, p.1400S>G; c.2768T>C, p.923I>T; c.5512T>C, p.1838F>L) were cosegregated with autosomal dominant inheritance of nonsyndromic sensorineural hearing loss in 3 unrelated Chinese families. Here, we show that MAP1B is highly expressed in the spiral ganglion neurons in the mouse cochlea. Using otic sensory neuron-like cells, generated by pluripotent stem cells from patients carrying the MAP1B mutation and control subject, we demonstrated that the p.1400S>G mutation caused the reduced levels and deficient phosphorylation of MAP1B, which are involved in the microtubule stability and dynamics. Strikingly, otic sensory neuron-like cells exhibited disturbed dynamics of microtubules, axonal elongation, and defects in electrophysiological properties. Dysfunctions of these derived otic sensory neuron-like cells were rescued by genetically correcting MAP1B mutation using CRISPR/Cas9 technology. Involvement of MAP1B in hearing was confirmed by audiometric evaluation of Map1b heterozygous KO mice. These mutant mice displayed late-onset progressive sensorineural hearing loss that was more pronounced in the high frequencies. The spiral ganglion neurons isolated from Map1b mutant mice exhibited the deficient phosphorylation and disturbed dynamics of microtubules. Map1b deficiency yielded defects in the morphology and electrophysiology of spiral ganglion neurons, but it did not affect the morphologies of cochlea in mice. Therefore, our data demonstrate that dysfunctions of spiral ganglion neurons induced by MAP1B deficiency caused hearing loss.

2019

New SNP variants of MARVELD2 (DFNB49) associated with non-syndromic hearing loss in Chinese population

Jing Zheng, Wen-Fang Meng, Chao-Fan Zhang, Hanqing Liu, Juan Yao, Hui Wang, Ye Chen, and Min-Xin Guan

J. Zhejiang Univ. Sci. B, Feb 2019

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Non-syndromic hearing loss (NSHL) is a common defect in humans. Variants of MARVELD2 at the DFNB49 locus have been shown to cause bilateral, moderate to profound NSHL. However, the role of MARVELD2 in NSHL susceptibility in the Chinese population has not been studied. Here we conducted a case-control study in an eastern Chinese population to profile the spectrum and frequency of MARVELD2 variants, as well as the association of MARVELD2 gene variants with NSHL. Our results showed that variants identified in the Chinese population are significantly different from those reported in Slovak, Hungarian, and Czech Roma, as well as Pakistani families. We identified 11 variants in a cohort of 283 NSHL cases. Through Sanger sequencing and bioinformatics analysis, we found that c.730G>A variant has detrimental effects in the eastern Chinese population, and may have relatively high correlation with NSHL pathogenicity.

2016

A Hypertension-Associated tRNAAla Mutation Alters tRNA Metabolism and Mitochondrial Function

Pingping Jiang, Meng Wang, Ling Xue, Yun Xiao, Jialing Yu, Hui Wang, Juan Yao, Hao Liu, Yanyan Peng, Hanqing Liu, Haiying Li, Ye Chen, and Min-Xin Guan

Mol. Cell. Biol., Jul 2016

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In this report, we investigated the pathophysiology of a novel hypertension-associated mitochondrial tRNA(Ala) 5655A →G (m.5655A →G) mutation. The destabilization of a highly conserved base pairing (A1-U72) at the aminoacyl acceptor stem by an m.5655A →G mutation altered the tRNA(Ala) function. An in vitro processing analysis showed that the m.5655A →G mutation reduced the efficiency of tRNA(Ala) precursor 5’ end cleavage catalyzed by RNase P. By using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mitochondrial DNA (mtDNA)-less (ρ(o)) cells, we showed a 41% reduction in the steady-state level of tRNA(Ala) in mutant cybrids. The mutation caused an improperly aminoacylated tRNA(Ala), as suggested by aberrantly aminoacylated tRNA(Ala) and slower electrophoretic mobility of mutated tRNA. A failure in tRNA(Ala) metabolism contributed to variable reductions in six mtDNA-encoded polypeptides in mutant cells, ranging from 21% to 37.5%, with an average of a 29.1% reduction, compared to levels of the controls. The impaired translation caused reduced activities of mitochondrial respiration chains. Furthermore, marked decreases in the levels of mitochondrial ATP and membrane potential were observed in mutant cells. These caused increases in the production of reactive oxygen species in the mutant cybrids. The data provide evidence for the association of the tRNA(Ala) 5655A →G mutation with hypertension.