scholarly journals Heterogeneity of Hepatic Stellate Cells in Fibrogenesis of the Liver: Insights from Single-Cell Transcriptomic Analysis in Liver Injury

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 2129
Author(s):  
Wenjun Zhang ◽  
Simon J. Conway ◽  
Ying Liu ◽  
Paige Snider ◽  
Hanying Chen ◽  
...  
Keyword(s):  
Liver Injury ◽  
Single Cell ◽  
Stellate Cell ◽  
Healing Process ◽  
Transcriptomic Analysis ◽  
Marker Genes ◽  
Liver Fibrogenesis ◽  
Human Livers ◽  
Underlying Mechanisms ◽  
Insight Into

Background & Aims: Liver fibrosis is a pathological healing process resulting from hepatic stellate cell (HSC) activation and the generation of myofibroblasts from activated HSCs. The precise underlying mechanisms of liver fibrogenesis are still largely vague due to lack of understanding the functional heterogeneity of activated HSCs during liver injury. Approach and Results: In this study, to define the mechanism of HSC activation, we performed the transcriptomic analysis at single-cell resolution (scRNA-seq) on HSCs in mice treated with carbon tetrachloride (CCl4). By employing LRAT-Cre:Rosa26mT/mG mice, we were able to isolate an activated GFP-positive HSC lineage derived cell population by fluorescence-activated cell sorter (FACS). A total of 8 HSC subpopulations were identified based on an unsupervised analysis. Each HSC cluster displayed a unique transcriptomic profile, despite all clusters expressing common mouse HSC marker genes. We demonstrated that one of the HSC subpopulations expressed high levels of mitosis regulatory genes, velocity, and monocle analysis indicated that these HSCs are at transitioning and proliferating phases at the beginning of HSCs activation and will eventually give rise to several other HSC subtypes. We also demonstrated cell clusters representing HSC-derived mature myofibroblast populations that express myofibroblasts hallmark genes with unique contractile properties. Most importantly, we found a novel HSC cluster that is likely to be critical in liver regeneration, immune reaction, and vascular remodeling, in which the unique profiles of genes such as Rgs5, Angptl6, and Meg3 are highly expressed. Lastly, we demonstrated that the heterogeneity of HSCs in the injured mouse livers is closely similar to that of cirrhotic human livers. Conclusions: Collectively, our scRNA-seq data provided insight into the landscape of activated HSC populations and the dynamic transitional pathway from HSC to myofibroblasts in response to liver injury.

Prolonged infusion of angiotensin II into normal rats induces stellate cell activation and proinflammatory events in liver

2003 ◽  
Vol 285 (3) ◽  
pp. G642-G651 ◽  
Author(s):  
Ramón Bataller ◽  
Erwin Gäbele ◽  
Robert Schoonhoven ◽  
Terry Morris ◽  
Mark Lehnert ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Liver Injury ◽  
Cell Activation ◽  
Stellate Cell ◽  
Elevated Serum ◽  
Inflammatory Cells ◽  
Binding Activity ◽  
Ang Ii ◽  
Dna Binding Activity ◽  
Liver Fibrogenesis

Recent evidence indicates that angiotensin II (ANG II) plays an important role in liver fibrogenesis. However, the underlying mechanisms are largely unknown. In advanced chronic liver diseases, circulating levels of ANG II are frequently elevated. We investigated the hepatic effects of prolonged systemic infusion of ANG II in normal rats. Saline or ANG II at subpressor and pressor doses (15 and 50 ng·kg-1·min-1, respectively) were infused to normal rats for 4 wk through a subcutaneous osmotic pump. Infusion of ANG II resulted in liver injury, as assessed by elevated serum liver enzymes. Livers from ANG II-perfused rats showed activation of JNK and ERK as well as increased NF-κB and activating protein-1 DNA-binding activity. Moreover, ANG II perfusion induced oxidative stress, increased concentration of proinflammatory cytokines, and upregulated the inflammatory proteins inducible nitric oxide synthase and cyclooxygenase-2. Histological examination of the livers from ANG II-infused rats showed mild portal inflammation as well as thickening and thrombosis of small hepatic vessels. ANG II-treated livers showed accumulation of CD43-positive inflammatory cells and activated hepatic stellate cells (HSCs) at the pericentral areas. A slight increase in collagen synthesis was observed, as assessed by Sirius red staining and hepatic hydroxyproline. All of these effects were observed when ANG II was perfused at subpressor and pressor doses. ANG II also accelerated the activation of primary cultured rat HSCs. In conclusion, increased systemic ANG II can induce liver injury by promoting proinflammatory events and vascular damage. ANG II-induced hepatic effects are not dependent on increase in arterial pressure.

Activation of peroxisome proliferator-activated receptor-γ contributes to the inhibitory effects of curcumin on rat hepatic stellate cell growth

2003 ◽  
Vol 285 (1) ◽  
pp. G20-G30 ◽  
Author(s):  
Jianye Xu ◽  
Yumei Fu ◽  
Anping Chen
Keyword(s):  
Gene Expression ◽  
Liver Injury ◽  
Hepatic Fibrosis ◽  
Stellate Cell ◽  
Healing Process ◽  
Wound Healing Process ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ

Hepatic fibrogenesis occurs as a wound-healing process after many forms of chronic liver injury. Hepatic fibrosis ultimately leads to cirrhosis if not treated effectively. During liver injury, quiescent hepatic stellate cells (HSC), the most relevant cell type, become active and proliferative. Oxidative stress is a major and critical factor for HSC activation. Activation of peroxisome proliferator-activated receptor-γ (PPAR-γ) inhibits the proliferation of nonadipocytes. The level of PPAR-γ is dramatically diminished along with activation of HSC. Curcumin, the yellow pigment in curry, is a potent antioxidant. The aims of this study were to evaluate the effect of curcumin on HSC proliferation and to begin elucidating underlying mechanisms. It was hypothesized that curcumin might inhibit the proliferation of activated HSC by inducing PPAR-γ gene expression and reviving PPAR-γ activation. Our results indicated that curcumin significantly inhibited the proliferation of activated HSC and induced apoptosis in vitro. We demonstrated, for the first time, that curcumin dramatically induced the gene expression of PPAR-γ and activated PPAR-γ in activated HSC. Blocking its trans-activating activity by a PPAR-γ antagonist markedly abrogated the effects of curcumin on inhibition of cell proliferation. Our results provide a novel insight into mechanisms underlying the inhibition of activated HSC growth by curcumin. The characteristics of curcumin, including antioxidant potential, reduction of activated HSC growth, and no adverse health effects, make it a potential antifibrotic candidate for prevention and treatment of hepatic fibrosis.

scholarly journals The antioxidant (−)-epigallocatechin-3-gallate inhibits activated hepatic stellate cell growth and suppresses acetaldehyde-induced gene expression

2002 ◽  
Vol 368 (3) ◽  
pp. 695-704 ◽  
Author(s):  
Anping CHEN ◽  
Li ZHANG ◽  
Jianye XU ◽  
Jun TANG
Keyword(s):  
Transforming Growth Factor ◽  
Stellate Cell ◽  
Present Report ◽  
Smooth Muscle Actin ◽  
Critical Role ◽  
Dependent Manner ◽  
Liver Fibrogenesis ◽  
Underlying Mechanisms

Activated hepatic stellate cells (HSC) are the primary source of excessive production of extracellular matrix during liver fibrogenesis. Although the underlying mechanisms remain incompletely understood, it is widely accepted that oxidative stress plays a critical role in liver fibrogenesis. Suppression of HSC growth and activation, as well as induction of apoptosis, have been proposed as therapeutic strategies for treatment and prevention of this disease. In the present report, we elucidated, for the first time, effects of the antioxidant (—)-epigallocatechin-3-gallate (EGCG), a major (and the most active) component of green tea extracts, on cultured HSC growth and activation. Our results revealed that EGCG significantly inhibited cultured HSC growth by inducing cell cycle arrest and apoptosis in a dose- and time-dependent manner. In addition, EGCG markedly suppressed the activation of cultured HSC as demonstrated by blocking transforming growth factor-β signal transduction and by inhibiting the expression of α1(I) collagen, fibronectin and α-smooth muscle actin genes induced by acetaldehyde, the most active metabolite of ethanol. Furthermore, EGCG reacted differently in the inhibition of nuclear factor-κB activity between cultured HSC with or without acetaldehyde stimulation. Taken together, our results indicated that EGCG was a novel and effective inhibitor for activated HSC growth and activation in vitro. Further studies are necessary to evaluate the effect of this polyphenol in prevention of quiescent HSC activation in vivo, and to further elucidate the underlying mechanisms.

scholarly journals Single-cell transcriptomic profiling of healthy and fibrotic adult zebrafish liver reveals conserved cell identities and stellate cell activation phenotypes with human liver

2021 ◽  
Author(s):  
Joshua K Morrison ◽  
Charles DeRossi ◽  
Isaac L Alter ◽  
Shikha Nayar ◽  
Mamta Giri ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Single Cell ◽  
Human Liver ◽  
Cell Activation ◽  
Stellate Cell ◽  
Cell Types ◽  
Marker Genes ◽  
Adult Zebrafish ◽  
Transcriptional Profiles ◽  
Zebrafish Liver

Liver fibrosis is the excessive accumulation of extracellular matrix that can progress to cirrhosis and failure if untreated. The mechanisms of fibrogenesis are multi-faceted and remain elusive with no approved antifibrotic treatments available. Here we use single-cell RNA sequencing (scRNA-seq) of the adult zebrafish liver to study the molecular and cellular dynamics of the liver at a single-cell level and demonstrate the value of the adult zebrafish as a model for studying liver fibrosis. scRNA-seq reveals transcriptionally unique populations of hepatic cell types that comprise the zebrafish liver. Joint clustering with human liver scRNA-seq data demonstrates high conservation of transcriptional profiles and human marker genes in zebrafish cell types. Human and zebrafish hepatic stellate cells (HSCs), the driver cell in liver fibrosis, specifically show conservation of transcriptional profiles and we uncover Colec11 as a novel, conserved marker for zebrafish HSCs. To demonstrate the power of scRNA-seq to study liver fibrosis, we performed scRNA-seq on our zebrafish model of a pediatric liver disease with characteristic early, progressive liver fibrosis caused by mutation in mannose phosphate isomerase (MPI). Comparison of differentially expressed genes from human and zebrafish MPI mutant HSC datasets demonstrated similar activation of fibrosis signaling pathways and upstream regulators. CellPhoneDB analysis revealed important receptor-ligand interactions within normal and fibrotic states. This study establishes the first scRNA-seq atlas of the adult zebrafish liver, highlights the high degree of similarity to the human liver, and strengthens its value as a model to study liver fibrosis.

scholarly journals Cell type identification from single-cell transcriptomes in melanoma

2021 ◽  
Vol 14 (S5) ◽  
Author(s):  
Qiuyan Huo ◽  
Yu Yin ◽  
Fangfang Liu ◽  
Yuying Ma ◽  
Liming Wang ◽  
...  
Keyword(s):  
Single Cell ◽  
Enrichment Analysis ◽  
Cell Types ◽  
Marker Genes ◽  
Cell Type ◽  
Computational Framework ◽  
Histocompatibility Complex ◽  
Differential Modules ◽  
Cell Gene ◽  
Insight Into

Abstract Background Single-cell sequencing approaches allow gene expression to be measured at the single-cell level, providing opportunities and challenges to study the aetiology of complex diseases, including cancer. Methods Based on single-cell gene and lncRNA expression levels, we proposed a computational framework for cell type identification that fully considers cell dropout characteristics. First, we defined the dropout features of the cells and identified the dropout clusters. Second, we constructed a differential co-expression network and identified differential modules. Finally, we identified cell types based on the differential modules. Results The method was applied to single-cell melanoma data, and eight cell types were identified. Enrichment analysis of the candidate cell marker genes for the two key cell types showed that both key cell types were closely related to the physiological activities of the major histocompatibility complex (MHC); one key cell type was associated with mitosis-related activities, and the other with pathways related to ten diseases. Conclusions Through identification and analysis of key melanoma-related cell types, we explored the molecular mechanism of melanoma, providing insight into melanoma research. Moreover, the candidate cell markers for the two key cell types are potential therapeutic targets for melanoma.

scholarly journals ClusterMap: Comparing analyses across multiple Single Cell RNA-Seq profiles

2018 ◽  
Author(s):  
Xin Gao ◽  
Deqing Hu ◽  
Madelaine Gogol ◽  
Hua Li
Keyword(s):  
Single Cell ◽  
Molecular Mechanisms ◽  
Population Level ◽  
Marker Genes ◽  
Rna Seq ◽  
Matching Problem ◽  
Cut Method ◽  
Underlying Mechanisms

AbstractSingle cell RNA-Seq facilitates the characterization of cell type heterogeneity and developmental processes. Further study of single cell profiles across different conditions enables the understanding of biological processes and underlying mechanisms at the sub-population level. However, developing proper methodology to compare multiple scRNA-Seq datasets remains challenging. We have developed ClusterMap, a systematic method and workflow to facilitate the comparison of scRNA profiles across distinct biological contexts. Using hierarchical clustering of the marker genes of each sub-group, ClusterMap matches the sub-types of cells across different samples and provides “similarity” as a metric to quantify the quality of the match. We introduce a purity tree cut method designed specifically for this matching problem. We use Circos plot and regrouping method to visualize the results concisely. Furthermore, we propose a new metric “separability” to summarize sub-population changes among all sample pairs. In three case studies, we demonstrate that ClusterMap has the ability to offer us further insight into the different molecular mechanisms of cellular sub-populations across different conditions. ClusterMap is implemented in R and available at https://github.com/xgaoo/ClusterMap.

ClusterMap: compare multiple single cell RNA-Seq datasets across different experimental conditions

2019 ◽  
Vol 35 (17) ◽  
pp. 3038-3045 ◽  
Author(s):  
Xin Gao ◽  
Deqing Hu ◽  
Madelaine Gogol ◽  
Hua Li
Keyword(s):  
Single Cell ◽  
Molecular Mechanisms ◽  
Population Level ◽  
Supplementary Information ◽  
Marker Genes ◽  
Rna Seq ◽  
Matching Problem ◽  
Experimental Conditions ◽  
Cut Method ◽  
Underlying Mechanisms

Abstract Motivation Single cell RNA-Seq (scRNA-Seq) facilitates the characterization of cell type heterogeneity and developmental processes. Further study of single cell profiles across different conditions enables the understanding of biological processes and underlying mechanisms at the sub-population level. However, developing proper methodology to compare multiple scRNA-Seq datasets remains challenging. Results We have developed ClusterMap, a systematic method and workflow to facilitate the comparison of scRNA-seq profiles across distinct biological contexts. Using hierarchical clustering of the marker genes of each sub-group, ClusterMap matches the sub-types of cells across different samples and provides ‘similarity’ as a metric to quantify the quality of the match. We introduce a purity tree cut method designed specifically for this matching problem. We use Circos plot and regrouping method to visualize the results concisely. Furthermore, we propose a new metric ‘separability’ to summarize sub-population changes among all sample pairs. In the case studies, we demonstrate that ClusterMap has the ability to provide us further insight into the different molecular mechanisms of cellular sub-populations across different conditions. Availability and implementation ClusterMap is implemented in R and available at https://github.com/xgaoo/ClusterMap. Supplementary information Supplementary data are available at Bioinformatics online.

miRNAs Signatures In Patients With Acute Liver Injury: Clinical Concerns and Correlations

2020 ◽  
Vol 20 (5) ◽  
pp. 325-335
Author(s):  
Hitarthi S. Vyas ◽  
Kapil K. Upadhyay ◽  
Ranjitsinh V. Devkar
Keyword(s):  
Liver Injury ◽  
Biological Significance ◽  
Clinical Findings ◽  
Cellular Regulation ◽  
Liver Injuries ◽  
The Status ◽  
Non Coding Rnas ◽  
Underlying Mechanisms ◽  
Insight Into

: Non-coding RNAs can be highly exploited for their biological significance in living systems. miRNAs are in the upstream position of cellular regulation cascade and hold merit in its state. A plethora of information is available on a wide variety of miRNAs that undergo alterations in experimentally induced models of liver injuries. The underlying mechanisms governed by these miRNAs have been inferred through cellbased experiments but the scientific knowledge on miRNA signatures in patients with liver injury are primordial and lack scientific clarity. Hence, it is crucial to get insight into the status and synergy of miRNAs in patients, with varying degrees of acute toxic manifestations in the liver. Though some miRNAs are being investigated in clinical trials, a major research lacuna exists with regard to the functional role of other miRNAs in liver diseases. This review article is a meticulous compilation of disease based or drug/alcohol based acute liver injuries in patients and resultant alteration in their miRNA profile. Investigative reports on underlying miRNA-liver crosstalk in cell-based or murine models are also discussed herein to draw a correlation with clinical findings.

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