10X Genomics single-cell RNA-Seq data set of CreER mice
Ontology highlight
ABSTRACT: The liver is organized into zones in which hepatocytes express different metabolic enzymes. The cells most responsible for liver repopulation and regeneration remain undefined because fate-mapping has only been performed on a few hepatocyte subsets. Fourteen mouse fate mapping strains were used to systematically compare distinct subsets of hepatocytes. During homeostasis, cells from both periportal zone 1 and pericentral zone 3 contracted in number, whereas cells from midlobular zone 2 expanded in number. These cells, which are sheltered from common injuries, also contributed to regeneration after pericentral and periportal injuries. Zone 2 repopulation was driven by the IGFBP2-mTOR-CCND1 axis. Hence, different regions of the lobule exhibit differences in their contributions to hepatocyte turnover, and zone 2 is the primary source of new hepatocytes during homeostasis and regeneration.
Project description:Single cell analyses of hepatocytes across the liver lobule demonstrated that gluconeogenic gene expression (Pck1 and G6pc) is relatively low in the fed state and gradually increase first in the periportal hepatocytes during the initial fasting period. As the time of fasting progresses, pericentral hepatocyte gluconeogenic gene expression increases and following entry into the starvation state the pericentral hepatocytes are not significantly different than the periportal hepatocytes. Similarly, pyruvate-dependent gluconeogenic activity is approximately 10-fold higher in the periportal hepatocytes during the initial fasting states but with only 1.5-fold different between the pericentral and periportal hepatocytes in the starvation state. In parallel, starvation induced a reduction of canonical beta-catenin signaling and redistribution of pericentral and periportal glutamine synthetase and glutaminase resulting in an enhanced pericentral glutamine-dependent gluconeogenesis. These data demonstrate that hepatocyte gluconeogenic gene expression and gluconeogenic activity are highly spatially and temporally plastic across the liver lobule and underscore the critical importance of using well-defined feeding and fasting times to define the basis of hepatic insulin resistance and glucose production.
Project description:Single cell analyses of hepatocytes across the liver lobule demonstrated that gluconeogenic gene expression (Pck1 and G6pc) is relatively low in the fed state and gradually increase first in the periportal hepatocytes during the initial fasting period. As the time of fasting progresses, pericentral hepatocyte gluconeogenic gene expression increases and following entry into the starvation state the pericentral hepatocytes are not significantly different than the periportal hepatocytes. Similarly, pyruvate-dependent gluconeogenic activity is approximately 10-fold higher in the periportal hepatocytes during the initial fasting states but with only 1.5-fold different between the pericentral and periportal hepatocytes in the starvation state. In parallel, starvation induced a reduction of canonical beta-catenin signaling and redistribution of pericentral and periportal glutamine synthetase and glutaminase resulting in an enhanced pericentral glutamine-dependent gluconeogenesis. These data demonstrate that hepatocyte gluconeogenic gene expression and gluconeogenic activity are highly spatially and temporally plastic across the liver lobule and underscore the critical importance of using well-defined feeding and fasting times to define the basis of hepatic insulin resistance and glucose production.
Project description:Single cell analyses of hepatocytes across the liver lobule demonstrated that gluconeogenic gene expression (Pck1 and G6pc) is relatively low in the fed state and gradually increase first in the periportal hepatocytes during the initial fasting period. As the time of fasting progresses, pericentral hepatocyte gluconeogenic gene expression increases and following entry into the starvation state the pericentral hepatocytes are not significantly different than the periportal hepatocytes. Similarly, pyruvate-dependent gluconeogenic activity is approximately 10-fold higher in the periportal hepatocytes during the initial fasting states but with only 1.5-fold different between the pericentral and periportal hepatocytes in the starvation state. In parallel, starvation induced a reduction of canonical beta-catenin signaling and redistribution of pericentral and periportal glutamine synthetase and glutaminase resulting in an enhanced pericentral glutamine-dependent gluconeogenesis. These data demonstrate that hepatocyte gluconeogenic gene expression and gluconeogenic activity are highly spatially and temporally plastic across the liver lobule and underscore the critical importance of using well-defined feeding and fasting times to define the basis of hepatic insulin resistance and glucose production.
Project description:The liver acts as a master regulator of metabolic homeostasis in part by performing gluconeogenesis. This process is dysregulated in type 2 diabetes, leading to elevated hepatic glucose output. The parenchymal cells of the liver (hepatocytes) are heterogeneous, existing on an axis between the portal triad and the central vein, and perform distinct functions depending on location in the lobule. Here, using single cell analysis of hepatocytes across the liver lobule, we demonstrate that gluconeogenic gene expression (Pck1 and G6pc) is relatively low in the fed state and gradually increases first in the periportal hepatocytes during the initial fasting period. As the time of fasting progresses, pericentral hepatocyte gluconeogenic gene expression increases, and following entry into the starvation state, the pericentral hepatocytes show similar gluconeogenic gene expression to the periportal hepatocytes. Similarly, pyruvate-dependent gluconeogenic activity is approximately 10-fold higher in the periportal hepatocytes during the initial fasting state but only 1.5-fold higher in the starvation state. In parallel, starvation suppresses canonical beta-catenin signaling and modulates expression of pericentral and periportal glutamine synthetase and glutaminase, resulting in an enhanced pericentral glutamine-dependent gluconeogenesis. These findings demonstrate that hepatocyte gluconeogenic gene expression and gluconeogenic activity are highly spatially and temporally plastic across the liver lobule, underscoring the critical importance of using well-defined feeding and fasting conditions to define the basis of hepatic insulin resistance and glucose production.
Project description:To investigate the underlying molecular principles of metabolic and morphogenic zonation of the human liver lobule, we generated an integrated epigenetic map across three zones (pericentral, intermediate and periportal) by methylation and transcriptomic analysis of hepatocytes captured by laser micro-dissection. We observe a deep link between epigenetic zonation of human liver and a zonated expression of metabolic and morphogenic pathways: Key transcriptionally zonated enzymes in xenobiotic and glutamine metabolism show a strong anticorrelated methylation gradient indicating that zonal expression of these genes is partly controlled by epigenetic programs. Zonated DNA-methylation at binding sites of uniformly expressed transcription factors such as HNF4A and RXRα points to an epigenetic layer in regulatory networks and a zonated activity of their nuclear ligands and drugs such as fibrates and bile acids. The same holds for genes of the wnt morphogen pathway whose expression show a zonated methylation at binding sites of TCF4L2. A strong pericentral expression of LGR5 and AXIN2 and a corresponding expression gradient of the liver progenitor marker TBX3, indicates a predominant pericentral source of hepatocyte regeneration under steady-state conditions in humans. Conversely, the periportal expression of NOTCH and EPCAM at the border to the biliary tree as source of regeneration under injury conditions. Overall our data provide a deep understanding of molecular control of the zonal organisation in the human liver.
Project description:The liver has a remarkable capacity for regeneration after injury. Midlobular hepatocytes have been proposed as the most plastic hepatic cell type, providing definitive evidence that zone 2 of the liver lobule acts as a reservoir for hepatocyte proliferation during homeostasis and regeneration. However, the implication of other mechanisms beyond hyperplasia that contribute to liver repair have been little explored and the collaboration of another hepatocyte subpopulation has differed among previous studies depending on the model of liver injury used. Thus, re-examination of dynamics of hepatocytes during regeneration is critical to get a better understanding of underlaying mechanisms for potential cell therapy and treatment of liver diseases. Here, using a mouse model of hepatocyte- and non-hepatocyte-specific multicolor lineage tracing, we demonstrate that hepatocytes located in the midlobular region also undergo hypertrophy besides cell division in response to chemical, physical, and viral insults. Our study shows for first time that this subpopulation also combats liver impairment after infection with coronavirus. Furthermore, we demonstrate that pericentral hepatocyte subpopulation also expands in number and size during the repair process in collaboration with midlobular hepatocytes and Galectin-9-CD44 pathway may be critical for driving these processes. Interestingly, we identified transdifferentiation and cell fusion processes during liver regeneration after severe injury that may be key to recover hepatic function.
Project description:The mammalian liver is composed of repeating hexagonal units termed lobules. Spatially-resolved single-cell transcriptomics revealed that about half of hepatocyte genes are differentially expressed across the lobule. Technical limitations impede reconstructing similar global spatial maps of other hepatocyte features. Here, we used zonated surface markers to sort hepatocytes from defined lobule zones with high spatial resolution. We applied transcriptomics, miRNA array measurements and Mass spectrometry proteomics to reconstruct spatial atlases of multiple zonated hepatocyte features. We found that protein zonation largely overlapped mRNA zonation, with the periportal HNF4α as an exception. We identified zonation of miRNAs such as miR-122, and inverse zonation of miRNAs and their hepatocyte target genes, implying potential regulation through zonated mRNA degradation. These targets included the pericentral Wnt receptors Fzd7 and Fzd8 and the periportal Wnt inhibitors Tcf7l1 and Ctnnbip1. Our approach facilitates reconstructing spatial atlases of multiple cellular features in the liver and other structured tissues.
Project description:Cholestatic injuries, featured with regional damage around the periportal, cause considerable mortality without curative therapies. It is technically challenging to dissect regional cell-cell interactions and molecular changes to fully understand cholangiopathies. Here, we generated a high-definition atlas of spatiotemporal transcriptome during cholestatic injury and repair. Remarkably, cholangiocytes functioned as a periportal hub by integrating signals from neighboring cells. We also dissected periportal damage, spatial heterogenous reprogramming and zonal regeneration, which appeared to be strongly associated with cholangiocyte. Moreover, spatiotemporal analyses revealed a key inhibitory rheostat for hepatocyte proliferation. Together, our study provides a comprehensive resource that is instrumental to demarcate regional cholestatic injury.
Project description:Hepatocytes of the mammalian liver are organized in liver lobules and operate in a spatially-dependent manner. Cells in different positions along the lobule’s porto-cenrtal axis, defined by the directionality of blood flow, express different genes and perform different liver tasks. Gradients of the transcriptome along liver lobule axis has been recently established, yet not for the hepatocyte proteome. We used two surface markers whose levels are inversely zonated – CD73 with a decreasing gradient from pericentral to periportal hepatocytes and E-cadherin with increasing gradient from portal to central hepatocytes. By staining for both surface markers, we efficiently isolated bulk populations of hepatocytes from distinct lobule layers by Fluorescence Activated Cell Sorting (FACS). Over all, we sorted 100,000 hepatocytes from each of eight spatially distinct populations, from five different mice. Cells were washed, digested by trypsin and subjected to LC-MS/MS. More cells from same populations from the same mice were also collected for mRNA sequencing and microRNA microarray profiling, to achieve a multi-omic view on spatially sorted hepatocytes, for better understanding of the transcriptomic and post-transcriptomic levels of regulation of liver zonation.
Project description:Single nucleus RNA-seq gene expression profiling was carried out for protein coding and lncRNA genes using nuclei extracted from livers from adult male and female mice; from male mice infused with GH continuously for one week, mimicking the female plasma GH pattern; and from male and female mice exposed to TCPOBOP, a xenobiotic agonist ligand of the nuclear receptor CAR, which perturbs sex-biased gene expression in the liver. Our analysis of these rich single nucleus, mouse liver transcriptomic datasets, comprised of 32,000 liver nuclei representing 9 major liver cell types, revealed: 1) the expression of sex-biased genes and their key GH-dependent transcriptional regulators is primarily restricted to hepatocytes and is largely not a feature of liver non-parenchymal cells; 2) many sex-biased transcripts show sex-dependent zonation within the liver lobule; 3) gene expression is substantially feminized in both periportal and pericentral hepatocytes when male mice are infused with GH continuously; 4) sequencing nuclei increases the sensitivity for detecting thousands of nuclear-enriched long-noncoding RNAs (lncRNAs) and enables determination of their liver cell type-specificity, sex-bias and hepatocyte zonation profiles; 5) the periportal to pericentral hepatocyte cell ratio is significantly higher in male than female liver; and 6) TCPOBOP exposure disrupts both sex-specific gene expression and hepatocyte zonation within the liver lobule. These findings highlight the complex interconnections between hepatic sexual dimorphism and zonation at the single-cell level and reveal how endogenous hormones and foreign chemical exposure can alter these interactions across the liver lobule with large effects on both protein-coding genes and lncRNAs.