Liver Network

Liver Network - Overview

We perfomed single-cell RNA-sequnecing of around 10,000 cells from normal human liver tissue to construct a human liver cell atlas. We reveal previously unknown subtypes in different cell type compartments. Overall design: Single cells were isolated from human liver resection specimens and then sorted by FACS into 384 well plates in a unbiased way and on the basis of cell surface markers for distinct cell types. ScRNA-seq was done using the mCelSeq2 protocol.

A Human Liver Cell Atlas reveals Heterogeneity and Epithelial Progenitors

The gene expression program underlying the specification of human cell types is of fundamental interest. We generated human cell atlases of gene expression and chromatin accessibility in fetal tissues. For gene expression, we applied three-level combinatorial indexing to >110 samples representing 15 organs, ultimately profiling ~4 million single cells. We leveraged the literature and other atlases to identify and annotate hundreds of cell types and subtypes, both within and across tissues. Our analyses focused on organ-specific specializations of broadly distributed cell types (such as blood, endothelial, and epithelial), sites of fetal erythropoiesis (which notably included the adrenal gland), and integration with mouse developmental atlases (such as conserved specification of blood cells). These data represent a rich resource for the exploration of in vivo human gene expression in diverse tissues and cell types.

A human cell atlas of fetal gene expression.

We identify specific contribution of each cell type to the human liver tumor microenvironment using unbiased approach at the single cell level. Our work constitutes an important resource for identifying potential sources of vulnerabilities in liver tumors and metastases.

A single cell atlas of the human liver tumor microenvironment

Current catalogs of regulatory sequences in the human genome are still incomplete and lack cell type resolution. To profile the activity of gene regulatory elements in diverse cell types and tissues in the human body, we applied single-cell chromatin accessibility assays to 30 adult human tissue types from multiple donors. We integrated these datasets with single-cell chromatin accessibility data from 15 fetal tissue types to reveal the status of open chromatin for approximately 1.2 million candidate cis-regulatory elements (cCREs) in 222 distinct cell types comprised of >1.3 million nuclei. We used these chromatin accessibility maps to delineate cell type-specificity of fetal and adult human cCREs and to systematically interpret the noncoding variants associated with complex human traits and diseases. This rich resource provides a foundation for the analysis of gene regulatory programs in human cell types across tissues, life stages, and organ systems. Overall design: Applying single cell chromatin accessibility assays to diverse human tissue types from four donors.

A single-cell atlas of chromatin accessibility in the human genome

Human intestinal organoids (HIOs) generated from pluripotent stem cells provide extraordinary opportunities to explore development and disease. Here, we generate a single-cell transcriptome reference atlas from HIOs and from multiple developing human organs to quantify the specificity of HIO cell fate acquisition, and to explore alternative fates. We identify epithelium-mesenchyme interactions, transcriptional regulators involved in cell fate specification, and stem cell maturation features in the primary tissue that are recapitulated in HIOs. We use an HIO time course to reconstruct the molecular dynamics of intestinal stem cell emergence, as well as the specification of multiple mesenchyme subtypes. We find that the intestinal master regulator CDX2 correlates with distinct phases of epithelial and mesenchymal development, and CDX2 deletion perturbs the differentiation of both intestinal epithelium and mesenchyme. Collectively our data provides a comprehensive and quantitative assessment of HIO development, and illuminates the molecular machinery underlying endodermal and mesodermal cell fate specification.

An organoid and multi-organ developmental cell atlas reveals multilineage fate specification in the human intestine

Throughout postnatal life, haematopoiesis in the bone marrow (BM) maintains blood and immune cell production. Haematopoiesis first emerges in human BM at 11-12 post conception weeks while fetal liver (FL) haematopoiesis is still expanding. Yet, almost nothing is known about how fetal BM evolves to meet the highly specialised needs of the fetus and newborn infant. Here, we detail the development of fetal BM including stroma using single cell RNA-sequencing. We find that the full blood and immune cell repertoire is established in fetal BM in a short time window of 6-7 weeks early in the second trimester. Fetal BM promotes rapid and extensive diversification of myeloid cells, with granulocytes, eosinophils and dendritic cell subsets emerging for the first time. B-lymphocytes expansion occurs, in contrast with erythroid predominance in FL at the same gestational age. We identify transcriptional and functional differences that underlie tissue-specific identity and cellular diversification in fetal BM and FL. Finally, we reveal selective disruption of B-lymphocyte, erythroid and myeloid development due to cell intrinsic differentiation bias as well as extrinsic regulation through an altered microenvironment in the fetal BM from constitutional chromosome anomaly Down syndrome during this crucial developmental time window. 

There are no restrictions on data availability for new data presented in this study. FASTQ and raw count matrices for droplet-based scRNA-seq data for FBM from fetuses with Down syndrome and fetuses without Down syndrome have been deposited at EMBL-EBI ArrayExpress and at the European Nucleotide Archive (ENA), with accession codes as follows: E-MTAB-9389 (FBM from fetuses with Down syndrome and FBM from fetuses without Down syndrome), E-MTAB-10042 (FBM from fetuses with Down syndrome) and ERP125305 (FBM from fetuses without Down syndrome). FASTQ and raw count matrices for all other new data in this study have been deposited at EMBL-EBI ArrayExpress and at the Gene Expression Omnibus (GEO) with accession codes E-MTAB-9801 (FBM Smart-seq2 scRNA-seq); E-MTAB-9389 (BCR- or TCR-enriched VDJ FBM scRNA-seq; FASTQs only); GSE166895 (CD34+ FBM, fetal liver and cord blood CITE-seq) and GSE166895 (FBM total CITE-seq). The following data are also available to download as Scanpy h5ad objects with transformed counts through our interactive webportal: https://fbm.cellatlas.io/: (i) FBM scRNA-seq (fetuses with Down syndrome); (ii) FBM scRNA-seq (fetuses without Down syndrome); (iii) CD34+ FBM, fetal liver and cord blood CITE-seq; and (iv) FBM total CITE-seq. All source data are available in the accompanying source data file, unless manuscript or figure legend refers to a Supplementary Table. External datasets incorporated into this study include: (i) human fetal liver and yolk sac scRNA-seq data4 (E-MTAB-7407); (ii) human blood monocyte–DC scRNA-seq data10 (GSE94820); (iii) mouse BM scRNA-seq data19 (GSE122467); (iv) fetal and paediatric thymus scRNA-seq data3 (E-MTAB-8581); and (v) adult BM and cord blood scRNA-seq data from the Human Cell Atlas Data Coordination Portal ‘Census of Immune Cells’ project (https://data.humancellatlas.org/explore/projects/cc95ff89-2e68-4a08-a234-480eca21ce79). At the time of submission, there are no known accessibility restrictions on these external datasets. Source data are provided with the paper.

Cell count:
Total post-QC is 164,709:
- 119,971 for 10x scRNA-seq (103,228 from fetal bone marrow; 16,743 from Down syndrome fetal bone marrow) 
- 486 for Smart-seq2 scRNA-seq (from fetal bone marrow)
- 44,252 for CITE-seq (35,273 from CD34+ fetal bone marrow, fetal liver, and cord blood; 8,978 from non-FACs sorted fetal bone marrow)

Blood and immune development in human fetal bone marrow and Down syndrome

The authors generated single-cell atlases of 23 lung, 16 kidney, 15 liver and 18 heart COVID-19 autopsy donor tissue samples, and spatial atlases of 14 lung donors.

COVID-19 tissue atlases reveal SARS-CoV-2 pathology and cellular targets.

Single-cell RNA sequencing was used to determine the cell type composition of all major human organs and construct a basic scheme for the human cell landscape (HCL).

Construction of A Human Cell Landscape by Single-cell mRNA-seq

Liver transplantation (LT) is the standard therapy for the patients with end-stage liver disease. The authors constructed a single-cell transcriptomic atlas of 58,243 liver cells from 4 donors and 4 recipient liver transplant patients.

Construction of a single-cell transcriptomic atlas of 58,243 liver cells from 4 donors and 4 recipient liver transplasnt patients to investigate early allograft dysfunction (EAD).

Despite their crucial role in health and disease, our knowledge of immune cells within human tissues remains limited. Here, we surveyed the immune compartment of 15 tissues of six deceased adult donors by single-cell RNA sequencing and paired VDJ sequencing. To systematically resolve immune cell heterogeneity across tissues, we developed CellTypist, a machine learning tool for rapid and precise cell type annotation. Using this approach, combined with detailed curation, we determined the tissue distribution of 45 finely phenotyped immune cell types and states, revealing hitherto unappreciated tissue-specific features and clonal architecture of T and B cells. In summary, our multi-tissue approach lays the foundation for identifying highly resolved immune cell types by leveraging a common reference dataset, tissue-integrated expression analysis and antigen receptor sequencing.

Cross-tissue immune cell analysis reveals tissue-specific features in humans

Despite our growing understanding of embryonic immune development, rare early megakaryocytes (MKs) remain relatively understudied. Here we used single-cell RNA sequencing of human MKs from embryonic yolk sac (YS) and fetal liver (FL) to characterize the transcriptome, cellular heterogeneity, and developmental trajectories of early megakaryopoiesis. In the YS and FL, we found heterogeneous MK subpopulations with distinct developmental routes and patterns of gene expression that could reflect early functional specialization. Intriguingly, we identified a subpopulation of CD42b+CD14+ MKs in vivo that exhibit high expression of genes associated with immune responses and can also be derived from human embryonic stem cells (hESCs) in vitro. Furthermore, we identified THBS1 as an early marker for MK-biased embryonic endothelial cells. Overall, we provide important insights and invaluable resources for dissection of the molecular and cellular programs underlying early human megakaryopoiesis.

Decoding Human Megakaryocyte Development

Definitive haematopoiesis in the fetal liver supports self-renewal and differentiation of haematopoietic stem cells/multipotent progenitors (HSC/MPPs), yet remains poorly defined in humans. Using single cell transcriptome profiling of ~133,000 fetal liver and ~65,000 fetal skin and kidney cells, we identify the repertoire of blood and immune cells in first and early second trimesters of development. From this data, we infer differentiation trajectories from HSC/MPPs, and evaluate the impact of tissue microenvironment on blood and immune cell development. We predict coupling of mast cell differentiation with erythro-megakaryopoiesis and identify physiological erythropoiesis in fetal skin. We demonstrate a shift in fetal liver haematopoietic composition during gestation away from being erythroid-predominant, accompanied by a parallel change in HSC/MPP differentiation potential, which we functionally validate. Our integrated map of fetal liver haematopoiesis provides a blueprint for the study of paediatric blood and immune disorders, and a valuable reference for understanding and harnessing the therapeutic potential of HSC/MPPs.

Decoding human fetal liver haematopoiesis

Cellular heterogeneity can emerge from the expression of only one parental allele, however it has remained unknown to what degree patterns of random monoallelic expression of autosomal genes (aRME) are mitotically inherited (clonal) or stochastic (dynamic) in somatic cells. Here, we resolved this by applying allele-sensitive single-cell RNA-seq on primary mouse fibroblasts and in vivo human T-cells to simultaneously investigate clonal and dynamic aRME. Dynamic aRME affected a considerable portion of the transcriptome, with levels dependent on the cell’s transcriptional activity, but clonal aRME was surprisingly scarce (<1% of genes) and affected mainly lowly expressed genes. Consequently, the overwhelming portion of aRME occurs transiently and is scattered throughout somatic populations rather than, as previously hypothesized, confined to spatially restricted patches of clonally related cells.

Dissecting the clonal nature of allelic expression in somatic cells by single-cell RNA-seq

The liver is the largest solid organ in the body and is critical for metabolic and immune functions. However, little is known about the cells that make up the human liver and its immune microenvironment. Here we report a map of the cellular landscape of the human liver using single-cell RNA sequencing. We provide the transcriptional profiles of 8444 parenchymal and non-parenchymal cells obtained from the fractionation of fresh hepatic tissue from five human livers. Using gene expression patterns, flow cytometry, and immunohistochemical examinations, we identify 20 discrete cell populations of hepatocytes, endothelial cells, cholangiocytes, hepatic stellate cells, B cells, conventional and non-conventional T cells, NK-like cells, and distinct intrahepatic monocyte/macrophage populations. Together, our study presents a comprehensive view of the human liver at single-cell resolution that outlines the characteristics of resident cells in the liver, and in particular provides a map of the human hepatic immune microenvironment.

Dissecting the human liver cellular landscape by single cell RNA-seq reveals novel intrahepatic monocyte/ macrophage populations

Melanoma brain metastasis (MBM) frequently occurs in patients with advanced melanoma; yet, our understanding of the underlying salient biology is rudimentary. Here, we performed single-cell/nucleus RNA-seq in 22 treatment-naive MBMs and 10 extracranial melanoma metastases (ECMs) and matched spatial single-cell transcriptomics and T cell receptor (TCR)-seq. Cancer cells from MBM were more chromosomally unstable, adopted a neuronal-like cell state, and enriched for spatially variably expressed metabolic pathways. Key observations were validated in independent patient cohorts, patient-derived MBM/ECM xenograft models, RNA/ATAC-seq, proteomics, and multiplexed imaging. Integrated spatial analyses revealed distinct geography of putative cancer immune evasion and evidence for more abundant intra-tumoral B to plasma cell differentiation in lymphoid aggregates in MBM. MBM harbored larger fractions of monocyte-derived macrophages and dysfunctional TOX+CD8+ T cells with distinct expression of immune checkpoints. This work provides comprehensive insights into MBM biology and serves as a foundational resource for further discovery and therapeutic exploration.

Dissecting the treatment-naive ecosystem of human melanoma brain metastasis.

Recent advances in single cell genomics technologies have facilitated studies on the developing immune system at unprecedented scale and resolution. However, these studies have focused on one or a few organs and were thus limited in understanding the developing immune system as a distributed network across tissues. Here, we profiled prenatal haematopoietic organs, lymphoid organs and non-lymphoid tissues using a combination of single-cell RNA sequencing, paired antigen-receptor sequencing and spatial transcriptomics to reconstruct the developing human immune system. Our analysis revealed the acquisition of immune effector transcriptome profiles in macrophages, mast cells and NK cells from the second trimester, and the transcriptomic changes accompanying the late-stage maturation of developing monocytes and T cells that extended from their organ of origin to peripheral tissues. We uncovered system-wide blood and immune cell development beyond the conventional primary haematopoietic organs. We further identified, extensively characterised and functionally validated the human prenatal B1 cells. Finally, we provide evidence for thymocyte-thymocyte selection origin for αβTCR- expressing unconventional T cells based on TCR gene usage and an in vitro artificial thymic organoid culture model. Our comprehensive atlas of the developing human immune system provides both valuable data resources and biological insights that will facilitate cell engineering, regenerative medicine and disease understanding. 

One-Sentence Summary 
By performing a comprehensive single-cell RNA sequencing atlas of human developing immune system together with antigen-receptor sequencing and spatial transcriptomics, we explored the cross-gestation and cross-organ variability in immune cells, discovered system-wide blood and immune cell development, identified, characterised and functionally validated the properties of human prenatal B1 cells and the origin of unconventional T cells.

Mapping the developing human immune system across organs

Hepatoblastoma (HB) is the most common primary liver malignancy of childhood. However, molecular investigations of the disease are limited and effective treatment options are lacking. The use of patient derived xenografts (PDX) to study biology and treatment strategies of HB has proven to be a useful tool. There is currently a knowledge gap in the investigation of key driver cells of HB in PDX models. Key driving pathways of HB tumor including WNT, AP-1, Hedgehog, Notch and MAPK pathways and genes such as GPC3, DLK1 and HMGA2 have been identified in primary HB tumor and PDX as integral players in HB tumor growth. Cell clusters have been defined with distinct roles in tumor development. Cell populations with initiating, angiogenic (endothelial), maintenance, and progression signatures have been identified in one HB patient tumor and corresponding PDX tumor. Critical pathways combined with identification of distinct cell populations within HB tumor will allow for investigation of novel treatment strategies in vitro and in vivo. Overall design: To examine HB pathways and define cell populations in a heterotopic PDX model, we implant patient source tumor into the intrascapular fat pad of female NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice. PDX tumor was compared to background liver and primary HB tumor and evaluated using single cell RNA sequencing (scRNAseq). 26,886 cells across 3 samples were collected after preprocessing and quality control.

Modeling Hepatoblastoma: Identification of Distinct Tumor Cell Populations and Key Genetic Mechanisms through Single Cell Sequencing (scRNA-seq)

We profile the transcriptomes of over 100,000 human single cells, yielding molecular definitions for non-parenchymal cell types present in healthy and cirrhotic human liver. We uncover a novel scar-associated TREM2+CD9+ macrophage subpopulation, which expands in liver fibrosis, differentiates from circulating monocytes, has a corollary population in mouse liver fibrosis and is pro-fibrogenic. We also define novel ACKR1+ and PLVAP+ endothelial cells which expand in cirrhosis, are topographically scar-restricted and enhance leucocyte transmigration. Multi-lineage ligand-receptor modelling of interactions between the novel scar-associated macrophages, endothelial cells and PDGFRα+ collagen-producing mesenchymal cells reveals intra-scar activity of several pro-fibrogenic pathways including TNFRSF12A, PDGFR and NOTCH signalling. Our work dissects unanticipated aspects of the cellular and molecular basis of human organ fibrosis at a single-cell level, and provides the conceptual framework required to discover rational therapeutic targets in liver cirrhosis.

Resolving the fibrotic niche of human liver cirrhosis using single-cell transcriptomics

The critical functions of the human liver are coordinated through the interactions of hepatic parenchymal and non-parenchymal cells. Recent advances in single cell transcriptional approaches have enabled an examination of the human liver with unprecedented resolution. However, dissociation related cell perturbation can limit the ability to fully capture the human liver's parenchymal cell fraction, which limits the ability to comprehensively profile this organ. Here, we report the transcriptional landscape of 73,295 cells from the human liver using matched single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA sequencing (snRNA-seq). The addition of snRNA-seq enabled the characterization of interzonal hepatocytes at single-cell resolution, revealed the presence of rare subtypes of hepatic stellate cells previously only seen in disease, and detection of cholangiocyte progenitors that had only been observed during in vitro differentiation experiments. However, T and B lymphocytes and NK cells were only distinguishable using scRNA-seq, highlighting the importance of applying both technologies to obtain a complete map of tissue-resident cell-types. We validated the distinct spatial distribution of the hepatocyte, cholangiocyte and stellate cell populations by an independent spatial transcriptomics dataset and immunohistochemistry. Our study provides a systematic comparison of the transcriptomes captured by scRNA-seq and snRNA-seq and delivers a high-resolution map of the parenchymal cell populations in the healthy human liver.

Single Cell, Single Nucleus and Spatial RNA Sequencing of the Human Liver Identifies Hepatic Stellate Cell and Cholangiocyte Heterogeneity

The liver parenchyma is composed of hepatocytes and bile duct epithelial cells (BECs). Controversy exists regarding the cellular origin of human liver parenchymal tissue generation during embryonic development, homeostasis or repair. Here we report the existence of a hepatobiliary hybrid progenitor (HHyP) population in human fetal liver using single-cell RNA sequencing. HHyPs are anatomically restricted to the ductal plate of fetal liver and maintain a unique transcriptional profile distinct from fetal hepatocytes, mature hepatocytes and mature BECs.  In addition, molecular heterogenicity within the EpCAM+ population of freshly isolated fetal and adult human liver reveals diverse gene expression signatures of hepatic and biliary lineage potential. Finally, we FACS isolated fetal HHyPs and confirmed their hybrid progenitor phenotype in vivo. Our study suggests that hepatobiliary progenitor cells previously identified in mice also exist in humans, and can be distinguished from other parenchymal populations, including mature BECs, by distinct gene expression profiles.

Single cell analysis of human fetal liver captures the transcriptional profile of hepatobiliary hybrid progenitors

Mesenchymal and endothelial cells were cell-sorted from healthy human (adult) livers (n=20), then single cell RNA sequencing was performed using the 10X Genomics Chromium platform

Single cell landscape of mesenchymal and endothelial cells in healthy human liver

Iterative liver injury results in progressive fibrosis disrupting hepatic architecture, regeneration potential, and liver function. Hepatic stellate cells (HSCs) are a major source of pathological matrix during fibrosis and are thought to be a functionally homogeneous population. Here, we use single-cell RNA sequencing to deconvolve the hepatic mesenchyme in healthy and fibrotic mouse liver, revealing spatial zonation of HSCs across the hepatic lobule. Furthermore, we show that HSCs partition into topographically diametric lobule regions, designated portal vein-associated HSCs (PaHSCs) and central vein-associated HSCs (CaHSCs). Importantly we uncover functional zonation, identifying CaHSCs as the dominant pathogenic collagen-producing cells in a mouse model of centrilobular fibrosis. Finally, we identify LPAR1 as a therapeutic target on collagen-producing CaHSCs, demonstrating that blockade of LPAR1 inhibits liver fibrosis in a rodent NASH model. Taken together, our work illustrates the power of single-cell transcriptomics to resolve the key collagen-producing cells driving liver fibrosis with high precision.

Single-Cell Transcriptomics Uncovers Zonation of Function in the Mesenchyme during Liver Fibrosis

The liver plays a critical role in both immune defense and tolerance in the body. The liver-resident immune cells (LrICs) determine the immune properties, but the unique composition and heterogeneity of these cells are incompletely understood. Here, we dissect the diversity of LrICs by a comprehensive transcriptomic profiling using unbiased single-cell RNA-sequencing (scRNA-seq). Overall design: 10x genomics was used to measure CD45+ immune cells in healthy human liver and paired spleen and PBMCs from the same donors.

Single-cell RNA sequencing reveals the heterogeneity of liver-resident immune cells in human.

The authors describe a protocol for efficient conversion of human primary hepatocytes into liver progenitor-like cells (HepLPCs) through delivery of developmentally relevant cues. 10X Genomics Single Cell Gene Expression was performed to comprehensively characterize cell subpopulations within the human hepatocyte-derived liver progenitor-like cells (HepLPCs). Human hepatocyte-derived liver progenitor-like cells (HepLPCs) were derived from one donor and cultured in transition and expansion medium until passage 5.

Single-cell RNA-Seq of human hepatocyte-derived liver progenitor-like cells

Immunotherapies have been explored in treating solid tumors, albeit with disparate clinical effects in distinct cancer types. Systematic interrogation of immune cells in the tumor microenvironment (TME) is vital to the prediction of immunotherapy response and the development of innovative immunotherapeutics. To comprehensively characterize the immune microenvironment in advanced biliary tract cancer (BTC), we utilized single-cell RNA sequencing in unselected viable cells from 16 matched samples. We identified nineteen cell subsets from a total of 45,851 cells, in which exhausted CD8+ T cells, macrophages, and dendritic cells (DCs) in BTC were shown to augment and communicate within the TME. Transcriptional profiles coupled with T cell receptor (TCR) sequences revealed that exhausted CD8+ T cells retained clonal expansion and high proliferation in the TME, and some of them highly expressed the endoplasmic reticulum stress (ER) sensor XBP1, indicating its key role in remodeling TME. Functional assays demonstrated that XBP1 and common immune checkpoints (PD1, TIGIT) were significantly upregulated in CD8+ T cells cocultured within the TME of BTC cell lines (GBC-SD, HCCC-9810). When treating the coculture groups with the specific inhibitor of IRE1α-XBP1 (4μ8C), the downregulation of TIGIT was observed in the treatment group. Collectively, comprehensive transcriptome profiling provides deeper insights into the immune atlas in advanced BTC, which might be instrumental in exploring novel immunotherapy strategies. Overall design: Five patients diagnosed with cholangiocarcinoma in the Eastern Hepatobiliary Surgery Hospital were incorporated into the current study, including two intrahepatic cholangiocarcinoma (iCCA), two gallbladder carcinoma (GBC) and one dCCA patients. Of note, none of the patients have undergone any preoperative treatments (chemotherapy, radiation or anti-tumor medicines) prior to tumor resection. Tumor primary locus and metastasis as well as lymph node were consistently harvested for each participant, if available. Meanwhile, peripheral blood samples were collected prior to surgical procedures using anticoagulant tubes.

Single-cell atlas of diverse immune populations in the advanced biliary tract cancer microenvironment

The functions of innate lymphoid cells (ILCs) in immune system are increasingly appreciated, whereas the early development of ILCs in human remains elusive. In this study, we sorted humanhematopoietic stem progenitor cells, lymphoid progenitors, presumed ILC progenitor/precursors and mature ILCs in the fetal hematopoietic, lymphoid and non-lymphoid tissues, from 8 to 12 PCW,for single-cell RNA-sequencing, followed by computational analysis and functional validation. We delineated the early phase of ILC development, from hematopoietic stem progenitor cells to multipotent lymphoid progenitors and to ILC progenitors, which mainly occurred in fetal liver and intestine. We further unveiled interleukin-3 receptor alpha (IL-3RA) as the surface marker for the lymphoid progenitors with T cell, B cell and ILC potentials. Notably, we determined the heterogeneity and tissue distribution of each ILC subpopulation, revealing the shared proliferating characteristics of the precursors of each ILC subtype. Additionally, a novel unconventional ILC2 subpopulation (CRTH2-CCR9+ ILC2) was identified in fetal thymus. Taken together, our study illuminates the precise cellular and molecular features underlying the stepwise formation of human fetal ILC hierarchy with remarkable spatiotemporal heterogeneity. Overall design: Here, we provided an unprecedented single-cell transcriptome atlas of stepwise ILC ontogeny in early human fetus using cells from fetal hematopoietic, lymphoid and non-lymphoid tissues spanning 8 to 12 post-conception weeks (PCWs).

Single-cell deciphering of human fetal innate lymphoid cell development

We isolated single cells (using either liberase or collagenase A dissociation) from subcutaneous adipose tissue collected from abdominoplasty surgery, and healthy liver tissue adjacent to tumor from liver resection and ran 10X v2 3' scRNA Seq.

Single-cell meta-analysis of SARS-CoV-2 entry genes across tissues and demographics.

Background: As core units of organ tissues, cells of various types play their harmonious rhythms to maintain the homeostasis of the human body. It is essential to identify the characteristics of cells in human organs and their regulatory networks for understanding the biological mechanisms related to health and disease. However, a systematic and comprehensive single-cell transcriptional profile across multiple organs of a normal human adult is missing. Results: We perform single-cell transcriptomes of 84,363 cells derived from 15 tissue organs of one adult donor and generate an adult human cell atlas. The adult human cell atlas depicts 252 subtypes of cells, including major cell types such as T, B, myeloid, epithelial, and stromal cells, as well as novel COCH+ fibroblasts and FibSmo cells, each of which is distinguished by multiple marker genes and transcriptional profiles. These collectively contribute to the heterogeneity of major human organs. Moreover, T cell and B cell receptor repertoire comparisons and trajectory analyses reveal direct clonal sharing of T and B cells with various developmental states among different tissues. Furthermore, novel cell markers, transcription factors and ligand-receptor pairs are identified with potential functional regulations in maintaining the homeostasis of human cells among tissues. Conclusions: The adult human cell atlas reveals the inter- and intra-organ heterogeneity of cell characteristics and provides a useful resource in uncovering key events during the development of human diseases in the context of the heterogeneity of cells and organs. Overall design: We performed single-cell transcriptomes of 84,363 cells derived from 15 tissue organs of one adult donor and generated an adult human cell atlas (AHCA). Keywords: Human cell atlas, Single-cell RNA sequencing, TCR, BCR, Transcriptome

Single-cell transcriptome profiling of an adult human cell atlas of 15 major organs

The liver is the largest solid organ in the body, yet it remains incompletely characterized. Here the authors present a spatial proteogenomic atlas of the healthy and obese human and murine liver combining single-cell CITE-seq, single-nuclei sequencing, spatial transcriptomics, and spatial proteomics. By integrating these multi-omic datasets, the authors provide validated strategies to reliably discriminate and localize all hepatic cells, including a population of lipid-associated macrophages (LAMs) at the bile ducts. Analysis of CITE-seq data, Nuclei RNA-seq data, and single-cell RNA-seq data on CD45+ and CD45- cells isolated from the livers of mice fed a standard diet (SD) or western diet (WD; fat, cholesterol, and sugar), and from healthy and steatotic human livers. Spatial Transcriptomics analysis on healthy mouse livers, NAFLD mouse livers, healthy human livers, and steatotic human livers.

Spatial proteogenomics reveals distinct and evolutionarily-conserved hepatic macrophage niches

We have created a compendium of single cell transcriptome data from the model
organism Mus musculus comprising more than 100,000 cells from 20 organs and
tissues. These data represent a new resource for cell biology, revealing gene
expression in poorly characterized cell populations and allowing for direct and
controlled comparison of gene expression in cell types shared between tissues, such
as T-lymphocytes and endothelial cells from distinct anatomical locations. Two
distinct technical approaches were used for most tissues: one approach, microfluidic
droplet-based 3’-end counting, enabled the survey of thousands of cells at relatively
low coverage, while the other, FACS-based full length transcript analysis, enabled
characterization of cell types with high sensitivity and coverage. The cumulative
data provide the foundation for an atlas of transcriptomic cell biology.

Tabula Muris: Transcriptomic characterization of 20 organs and tissues from Mus musculus at single cell resolution

In recent years there has been tremendous progress towards deep molecular characterization of cell types using single cell transcriptome sequencing. Here we report a single cell transcriptomic atlas comprising nearly 500,000 cells from 24 different human tissues and organs. In several instances multiple organs were analyzed from the same donor. Analyzing organs from the same individual controls for genetic background, age, environment, and epigenetic effects, and enables a detailed comparison of cell types that are shared between tissues. This resource provides a rich molecular characterization of more than 400 cell types, their distribution across tissues, and detailed information about tissue specific variation in gene expression. We have used the fact that multiple tissues came from the same donor to study the clonal distribution of T cells between tissues, to understand the tissue specific mutation rate in B cells, and to analyze the cell cycle state and proliferative potential of shared cell types across tissues. Finally, we have also used this data to characterize cell type specific RNA splicing and how such splicing varies across tissues within an individual.

Liver Network

Network Description

Liver Network atlases are still under development.

Network Coordinators