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. Overall design: Primary samples from 5 2nd trimester human fetal livers and 3 uninjured adult human livers for single cell RNA sequencing by Smartseq2.
Single cell analysis of human foetal liver captures the transcriptional profile of hepatobiliary hybrid progenitors.
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View SamplesMonoallelic expression of autosomal genes (MAE) is a widespread epigenetic phenomenon which is poorly understood, due in part to current limitations of genome-wide approaches for assessing it. Recently, we reported that a specific histone modification signature is strongly associated with MAE, and demonstrated that it can serve as a proxy of MAE in human lymphoblastoid cells (Nag et al. Elife. 2013 Dec 31;2:e01256). Here, we use murine cells to establish that this chromatin signature is conserved between mouse and human, and is associated with MAE in every tested cell type. Our analyses reveal extensive conservation in the identity of MAE genes between the two species. By applying MAE chromatin signature analysis to a large number of cell and tissue types, we show that the MAE state remains consistent during terminal cell differentiation and is predominant among cell-type specific genes, suggesting a link between MAE and specification of cell identity. Overall design: PolyA RNA purification and subsequent high-throughput sequencing were performed on two independent B-lymphoid clonal cell line, derived from 129S1/SvImJ x CAST/EiJ F1 mice and immortalized with Abelson murine leukemia virus, and on two independent fibroblast clonal cell lines, derived from 129S1/Sv x CAST/EiJ F1 and immortalized with SV40.
Chromatin Signature Identifies Monoallelic Gene Expression Across Mammalian Cell Types.
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View SamplesZinc is both an essential and potentially toxic metal. It is widely believed that oral zinc supplementation can reduce the effects of the common cold; however, there is strong clinical evidence that intranasal (IN) zinc gluconate (ZG) gel treatment for this purpose causes anosmia, or the loss of the sense of smell, in humans. Using the rat olfactory neuron cell line, Odora, we investigated the molecular mechanism by which zinc exposure exerts its toxic effects on olfactory neurons. Following treatment of Odora cells with 100 and 200 µM ZG for 0-24 h, RNA-seq and in silico analyses revealed up-regulation of pathways associated with zinc metal response, oxidative stress, and ATP production. We observed that Odora cells recovered from zinc-induced oxidative stress, but ATP depletion persisted with longer exposure to ZG. ZG exposure increased levels of NLRP3 and IL-1ß protein levels in a time-dependent manner, suggesting that zinc exposure may cause an inflammasome-mediated cell death, pyroptosis, in olfactory neurons. Overall design: 5 treatment groups, 3 replicates/group, 1 control group, 3 groups treated with 100 µM zinc gluconate for increasing time (6, 12, and 24 h), 1 group treated with 200 µM zinc gluconate for 6 h
Mechanistic studies of the toxicity of zinc gluconate in the olfactory neuronal cell line Odora.
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View SamplesCholecystokinin (CCK) is a satiety hormone produced by discrete enteroendocrine cells scattered among absorptive cells of the small intestine. CCK is released into blood following a meal; however, the mechanisms inducing hormone secretion are largely unknown. Ingested fat is the major stimulant of CCK secretion. We recently identified a novel member of the lipoprotein remnant receptor family known as immunoglobulin-like domain containing receptor 1 (ILDR1) in intestinal CCK cells and postulated that this receptor conveyed the signal for fat-stimulated CCK secretion. In the intestine, ILDR1 is expressed exclusively in CCK cells. Orogastric administration of fatty acids elevated blood levels of CCK in wild type but not ILDR1-deficient mice, although the CCK secretory response to trypsin inhibitor was retained. The uptake of fluorescently labeled lipoproteins in ILDR1-transfected CHO cells and release of CCK from isolated intestinal cells required a unique combination of fatty acid plus HDL. CCK secretion secondary to ILDR1 activation is associated with increased [Ca2+]i consistent with regulated hormone release. These findings demonstrate that ILDR1 regulates CCK release through a mechanism dependent on fatty acids and lipoproteins and that absorbed fatty acids regulate gastrointestinal hormone secretion.
Immunoglobulin-like domain containing receptor 1 mediates fat-stimulated cholecystokinin secretion.
Specimen part
View SamplesB16F1 cells are a good model to study cell motility and cytoskeletal organization. In our lab, a combination of microscopy and gene silencing was used to approach the problem. Having gene expression profiles for B16F1 would facilitate and support subsequent gene silencing by RNAi as well as potentially identify new molecular players.
Role of fascin in filopodial protrusion.
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View SamplesLateral Organ Boundary Domain (LBD) transcription factors are specific of plants and are involved in the control of development. One LBD clade is related to the control of root development (Coudert et al., 2013, Mol. Biol. Evol. 30, 569-572). Belonging to this clade, CROWN ROOT LESS 1 controls the initiation of crown roots in rice (Inukai Plant Cell, 17, 1387-1396, Liu et al., 2005, Plant J., 43, 47-56). The aim of this study was to identify the genes that are regulated by CRL1.
Identification of CROWN ROOTLESS1-regulated genes in rice reveals specific and conserved elements of postembryonic root formation.
Specimen part, Treatment
View SamplesMicroRNA 155 (miR-155) has been shown to regulate the gene expression of important players of physiological and pathological processes, like hematopoietic lineage differentiation, immunity and inflammation, viral infections, cancer and cardiovascular diseases, among others. Degranulation is an event in which mast cells, upon activation of the FceRI, release their granule content rich in vasoactive amines, proteases and TNFa. Additionally activation of the receptor promotes de novo synthesis of cytokines, chemokines and growth factors. Analysis of bone marrow derived mast cells (BMMC) deficient in miR-155 showed a significant increase in FceRI mediated degranulation and in the release of cytokines like TNFa, IL-6 and IL-13. In addition miR 155-/- mice presented higher anaphylaxis reactions compared to WT mice. Gene expression analysis of BMMC was performed in order to identify intermediaries of FceRI mediated degranulation under the control of miR-155. The results indicate that miR-155 regulates negatively the expression of the regulatory subunits of the kinase PI3Kgamma, Pik3r5 (p101) and Pik3r6 (p84, p87PIKAP), involved in Ca+ influx and degranulation.
miRNA-155 controls mast cell activation by regulating the PI3Kγ pathway and anaphylaxis in a mouse model.
Specimen part
View SamplesIn contrast to the migration of leukocytes from blood vessels into tissues, and the involvement of adhesion molecules and chemokines in this process, the migration of leukocytes from the tissue into lymphatic vessels is much less well understood. This can, in part be explained by the fact that murine lymphatic endothelial cells (LECs) have proven particularly hard to isolate and propagate in culture. Hence, it has been difficult to establish suitable models to study this process in vitro. Combining magnetic bead-based purification and fluorescence-activated cell sorting (FACS), we have isolated LECs (immorto-LECs) from the skin of mice which express a temperature-sensitive SV40 large T antigen (H-2Kb-tsA58 mice; ImmortoMice) in all cell types under the control of the MHC-class-I-promotor, H-2Kb. The isolated cells are viable for more than 30 passages when cultured at 33 C, the temperature at which the large T antigen is stably expressed. Furthermore, immorto-LECs tolerate several days of culture at 37 C, but become senescent if continuously cultured at this temperature. All cells stably express endothelial and lymphatic markers like CD31, podoplanin, Prox-1 and VEGFR-3 up to passage 30. When cultured in presence of tumor necrosis factor-alpha (TNF-a), immorto-LECs upregulate adhesion molecules, such as ICAM-1, VCAM-1 and E-selectin, similarly to what has been reported to occur under inflammatory conditions in vivo. Overall, our findings establish immorto-LECs as a useful and handy tool for the in vitro investigation of immune cell transmigration across lymphatic endothelium.
Tissue inflammation modulates gene expression of lymphatic endothelial cells and dendritic cell migration in a stimulus-dependent manner.
Specimen part
View SamplesUsing a stromal cell free system, we described the gene expression and two genome wide epigenetic profiles of a unique population of undifferentiated bone marrow cells selectively driven towards the T cell differentiation pathway
An epigenetic profile of early T-cell development from multipotent progenitors to committed T-cell descendants.
Specimen part, Treatment
View SamplesRegulatory T cells (Tregs) can suppress a wide variety of cell types, in diverse organ sites and inflammatory conditions. While Tregs possess multiple suppressive mechanisms, the number required for maximal function is unclear. Furthermore, whether any inter-relationship orcross-regulatory mechanisms exist that areused to orchestrate and control their utilization is unknown. Here we assessed the functional capacity of Tregs lacking the ability to secrete both interleukin-10 (IL-10) and IL-35, which individually are required for maximal Treg activity. Surprisingly, IL-10/IL-35-double deficient Tregswere fully functionalin vitro and in vivo. Loss of IL-10 and IL-35 was compensated for by a concurrent increase in cathepsin E (CTSE) expression, enhanced TRAIL (Tnfsf10)expression and soluble TRAIL release, rendering IL-10/IL-35-double deficient Tregsfunctionally dependent on TRAIL in vitro and in vivo. Lastly, while C57BL/6 Tregs are IL-10/IL-35-dependent, Balb/c Tregs, which express high levels of CTSE and enhanced TRAIL expression, are TRAIL-dependent.These data reveal that cross-regulatory pathways exist, which control the utilization of suppressive mechanisms,thereby providing Tregfunctional plasticity.
The plasticity of regulatory T cell function.
Specimen part
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