Project description:Aim of the study was to characterize at a molecular level (changes in transcriptomes) the crosstalk between tumor hepatocytes and activated hepatic stellate cells (HSC) in liver cancer. This was adressed by using a coculture model system of HepaRG cell line (tumor hepatocytes, human), and LX2 cell line (HSC, human). By using genome-wide expression profiling, we demonstrated that hepatocyte-HSC crosstalk is bidirectional and results in the deregulation of functionally relevant gene networks.
Project description:Aim of the study was to characterize at a molecular level (changes in transcriptomes) the crosstalk between tumor hepatocytes and activated hepatic stellate cells (HSC) in liver cancer. This was adressed by using a coculture model system of HepaRG cell line (tumor hepatocytes, human), and LX2 cell line (HSC, human). By using genome-wide expression profiling, we demonstrated that hepatocyte-HSC crosstalk is bidirectional and results in the deregulation of functionally relevant gene networks. HepaRG and LX2 cells were cultured alone in serum- and DMSO-free William's E medium or together using 1 M-BM-5m pore size transwell inserts which allow diffusion of media components but prevent cell migration (BD Biosciences, San Jose, CA). Triplicate experiments were performed: HepaRG (culture versus coculture), LX2 (culture versus coculture).
Project description:The molecular determinants of a healthy human liver cell phenotype remain largely uncharacterized. In addition, the gene expression changes associated with activation of primary human hepatic stellate cells, a key event during fibrogenesis, remain poorly characterized. Here, we provide the transriptomic profile underpinning the healthy phenotype of human hepatocytes, liver sinusoidal endothelial cells (LSECs) and quiescent hepatic stellate cells (qHSCs) as well as activated HSCs (aHSCs) We assess the transcriptome for purified, non-cultured human hepatocytes, liver sinusoidal cells (LSECs) and quiescent hepatic stellate cells (qHSCs) as well as culture-activated HSCs (aHSCs). Hepatocytes (n=2 donors), LSECs (n=3), qHSCs (n=3) and in vitro activated HSCs (n=3; from the same donors as the qHSCs and LSECs) were used for this study.
Project description:The molecular determinants of a healthy human liver cell phenotype remain largely uncharacterized. In addition, the gene expression changes associated with activation of primary human hepatic stellate cells, a key event during fibrogenesis, remain poorly characterized. Here, we provide the transriptomic profile underpinning the healthy phenotype of human hepatocytes, liver sinusoidal endothelial cells (LSECs) and quiescent hepatic stellate cells (qHSCs) as well as activated HSCs (aHSCs) We assess the transcriptome for purified, non-cultured human hepatocytes, liver sinusoidal cells (LSECs) and quiescent hepatic stellate cells (qHSCs) as well as culture-activated HSCs (aHSCs).
Project description:We model liver phenotypes associated with telomere dysfunction using DC patient-derived iPS cells and isogenic controls with CRISPR/Cas9-mediated homology-directed repair correction of the disease-causing DKC1 mutation. Differentiation of these cells into hepatocyte-like cells or hepatic stellate cells indicates that the parenchymal hepatocytes are primarily affected by telomere dysfunction. We develop an admixed hepatostellate organoid culture model which further reveals that mutant hepatocytes exert dominant effects on hepatic stellate cells regardless of stellate cell genotype. Hepatostellate organoids containing DKC1-mutant hepatocytes exhibit hyperplasia in both the hepatocyte compartment and, remarkably, in stellate cells. Moreover, mutant hepatocytes can induce hallmarks of stellate cell activation independently of stellate cell genotype. Interestingly, mutant hepatostellate organoids also contain off-target PLVAP+ endothelial cells reminiscent of scar-associated endothelium observed in non-DC cirrhosis patients.
Project description:A unique feature of the liver is its high regenerative capacity, which is essential to maintain liver homeostasis. However, key regulators of liver regeneration (LR) remain ill-defined. Here, we identify hepatic miR-182-5p as a key regulator of LR. Suppressing miR-182-5p, whose expression is significantly induced in the liver of mice post two-thirds partial hepatectomy (PH), abrogates PH-induced LR in mice. In contrast, liver-specific overexpression of miR-182-5p promotes LR in mice with PH. Overexpression of miR-182-5p failed to promote proliferation in hepatocytes, but stimulates proliferation when hepatocytes are cocultured with stellate cells. Mechanistically, miR-182-5p stimulates Cyp7a1-mediated cholic acid production in hepatocytes, which promotes hedgehog (Hh) ligand production in stellate cells, leading to the activation of Hh signaling in hepatocytes and consequent cell proliferation. Collectively, our study identified miR-182-5p as a critical regulator of LR and uncovers a Cyp7a1/cholic acid-dependent mechanism by which hepatocytes crosstalk to stellate cells to facilitate LR.
Project description:Liver fibrosis is a reversible wound-healing response to liver injury and hepatic stellate cells (HSCs) are central cellular players that mediate hepatic fibrogenesis. However, the molecular mechanisms that govern this process remain unclear. Here, we reveal a novel cistromic circuit in HSCs comprising the vitamin D receptor (VDR) and SMAD transcription factors that restrains the intensity of hepatic fibrogenesis. Ligand-activated VDR suppresses TGFβ1-induced pro-fibrotic gene expression in HSCs. Administration of a vitamin D analogue, calcipotriol, diminishes the fibrotic response in a mouse model of liver fibrosis, while VDR knockout mice spontaneous develop extensive hepatic fibrosis by age 6 months. Using ChIP-Seq, we find that the anti-fibrotic properties of VDR are due to crosstalk with SMAD, mediated by their co-occupancy of DNA-binding sites on pro-fibrotic genes. Specifically, SMAD binding potentiates local chromatin accessibility to enhance VDR recruitment at the same cis-regulatory elements, which reciprocally antagonizes the interaction between SMAD3 and chromatin and limits the assembly of transcriptional activation complexes at fibrotic genes, a process that is enhanced by the presence of VDR agonists. These results not only establish this coordinated VDR/SMAD cistromic circuit as a master regulator of hepatic fibrogenesis, but also support VDR as a potential drug target to ameliorate liver fibrosis. Identification of VDR, SMAD3 and H3 binding sites in human stellate LX2 cells that were pre-treated with calcipotriol (100nM) for 16 hrs (where calcipotriol treatment is indicated) followed by incubation of calcipotriol (100nM) or TGFβ1 (1ng/ml) for another 4 hours (where indicated).
Project description:We generated a high-resolution cellular atlas of the healthy human liver by profiling the transcriptome of more than 25,000 individual liver cells using droplet-based RNA-sequencing. Recently published datasets and in situ hybridization were integrated to confirm, validate and locate newly identified cell populations. We identified, annotated and characterized a total of 23 cell subpopulations that represent the degree of heterogeneity of parenchymal (i.e. hepatocytes and cholangiocytes) and non-parenchymal liver cells (i.e. endothelial cells, stellate cells, macrophages and lymphoid cells). We successfully classified human hepatocytes and liver sinusoidal endothelial cells along the porto-central axis and for the first time reveal the existence of functionally specialized pericentral GPC3+ and periportal HHIP+ DBH+ hepatic stellate cells in the healthy human liver. Our study provides a description of the different cell compartments that enter into the composition of a healthy human liver and currently constitutes the biggest single-cell RNA sequencing dataset available on human healthy hepatocytes and hepatic stellate cells. We identified subsets of hepatic stellate cells characterized by distinct localization and physiological functions.
Project description:The communacation between the Hepatocellular carcinoma (HCC) and hepatic stellate cells(HSC) is not completely understood. Then a tumor-on-a-chip model was used to evaluate the crosstalk between the HCC cells (HCCLM3) and HSCs (LX2). After 5 days co-culture, we degraded the collagen hydrogel to isolate HCCLM3 cells and LX2 cells for RNA-seq.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes