Cellular senescence is a program of irreversible cell cycle arrest that normal cells undergo in response to progressive shortening of telomeres, changes in telomeric structure, oncogene activation or oxidative stress. The underlying signalling pathways, potentially of major clinicopathological relevance, are unknown. A major stumbling block to studying senescence has been the absence of suitable model systems because of the asynchrony of this process in heterogeneous cell populations. To simplify this process many investigators study oncogene-induced senescence due to expression of activated oncogenes where senescence occurs prematurely without telomere attrition and can be induced acutely in a variety of cell types. We have taken a different approach by making use of the finding that reconstitution of telomerase activity by introduction of the catalytic subunit of human telomerase alone is incapable of immortalising all human somatic cells, but inactivation of the p16-pRB and p53-p21 pathways are required in addition. The ability of SV40 large T antigen to inactivate the p16-pRB and p53-p21 pathways has enabled us to use a thermolabile mutant of LT antigen, in conjunction with hTERT, to develop conditionally immortalised human (HMF3A) fibroblasts that are immortal but undergo an irreversible growth arrest when the thermolabile LT antigen is inactivated leading to activation of pRB and p53. When these cells cease dividing, senescence-associated- b-galactosidase activity is induced and the growth-arrested cells have morphological features and express genes in common with senescent cells. Since these cells growth arrest in a synchronous manner they are an excellent starting point for dissecting the pathways that underlie cellular senescence and act downstream of p16-pRB and p53-p21 pathways. We have combined genome-wide expression profiling with genetic complementation to undertake identification of genes that are differentially expressed when these conditionally immortalised human fibroblasts undergo senescence upon activation of the p16-pRB and p53-p21 tumour suppressor pathways.
Activation of nuclear factor-kappa B signalling promotes cellular senescence.
Cell line, Treatment
View SamplesAlcoholic hepatitis (AH) is the most severe form of alcoholic liver disease and occurs in patients with excessive alcohol intake It is characterized by marked hepatocellular damage, steatosis and pericellular fibrosis. Patients with severe AH have a poor short-term prognosis. Unfortunately, current therapies (i.e. corticosteroids and pentoxyphylline) are not effective in many patients and novel targeted therapies are urgently needed. The development of such therapies is hampered by a poor knowledge of the underlying molecular mechanisms. Based on studies from animal models, TNF alfa was proposed to play a pivotal role in the mechanisms of AH. Consequently, drugs interfering TNF alfa were tested in these patients. The results were disappointing due to an increased incidence of severe infections. Unluckily, there are not experimental models that mimic the main findings of AH in humans. To overcome this limitation, translational studies with human samples are required. We previously analyzed samples from patients with biopsy-proven AH. In these previous studies, we identified CXC chemokines as a potential therapeutic target for these patients. We expanded these previous observations by performing a high-throughout transcriptome analysis.
Transcriptome analysis identifies TNF superfamily receptors as potential therapeutic targets in alcoholic hepatitis.
No sample metadata fields
View SamplesThe in vitro directed differentiation of pluripotent stem cells (PSCs) through stimulation of developmental signaling pathways can generate mature somatic cell types for basic laboratory studies or regenerative therapies.
Pluripotent stem cell differentiation reveals distinct developmental pathways regulating lung- versus thyroid-lineage specification.
Treatment
View SamplesDiffuse large B-cell lymphoma (DLBCL) has striking clinical and molecular variability. Although a more precise identification of the multiple determinants of this variability is still under investigation, there is a consensus that high-clinical-risk DLBCL cases require a risk-adapted therapy, since intensification of chemotherapy with autologous stem-cell transplantation (ASCT) has been shown to improve the prognosis for high-risk patients in randomised clinical trials.
Identification of biological markers of sensitivity to high-clinical-risk-adapted therapy for patients with diffuse large B-cell lymphoma.
No sample metadata fields
View SamplesThe objective of the present study is to investigate if females have the ability to recognise X or Y chromosome bearing spermatozoa and present a different response to different spermatozoa.
The battle of the sexes starts in the oviduct: modulation of oviductal transcriptome by X and Y-bearing spermatozoa.
Specimen part
View SamplesWe previously showed that severe liver diseases are characterized by expansion of liver progenitor cells (LPC), which correlates with disease severity. However, the origin and role of LPC in liver physiology and in the hepatic response to injury remains a contentious topic. We have now used genetic lineage tracing of Hnf1-expressing biliary duct cells to assess their contribution to LPC expansion and hepatocyte generation during normal liver homeostasis, and following different types of liver injury. We found that ductular reaction cells in human cirrhotic livers express HNF1. However, HNF1 expression was not present in newly generated EpCAM-positive hepatocytes. Using a tamoxifen-inducible Hnf1CreER/R26RYFP/LacZ mouse, we show that there is no contribution of the biliary epithelium to hepatocyte turnover during liver homeostasis in healthy mice. Moreover, after loss of liver mass, Hnf1+ LPC did not contribute to hepatocyte regeneration. We also assessed the contribution of Hnf1+ cells following acute and repeated liver injury. All animal models showed expansion of LPC, as assessed by immunostaining and gene expression profile of sorted YFP-positive cells. A contribution of Hnf1+ LPC to hepatocyte generation was not detected in animal models of liver injury with preserved hepatocyte regenerative potential such as acute acetaminophen, carbon tetrachloride injury, or chronic diethoxycarbonyl-1,4-dihydro-collidin (DDC)-diet. However, in mice fed with choline-deficient ethionine-supplemented (CDE)-diet, which causes profound hepatocyte damage and arrest, a small number of hepatocytes were derived from Hnf1+ cells. Conclusion: Hnf1+ cells do not participate in hepatocyte turnover in the healthy liver or during liver regeneration after partial hepatectomy. After liver injury, LPC arise from the biliary duct epithelium, which gives rise to a limited number of hepatocytes only when hepatocyte regeneration is compromised.
The biliary epithelium gives rise to liver progenitor cells.
No sample metadata fields
View SamplesHepatic fibrosis, the wound-healing response to repeated liver injury, ultimately leads to cirrhosis. There is an urgent need to develop effective antifibrotic therapies. Ghrelin (encoded by Ghrl) is an orexigenic hormone that has pleiotrophic functions including protection against cell death1. Here we investigate whether ghrelin modulates liver fibrosis and protects from acute liver injury. Recombinant ghrelin reduced the fibrogenic response to prolonged bile duct ligation in rats. This effect was associated with decreased liver injury and myofibroblast accumulation as well as attenuation of the altered gene expression profile. Ghrelin also reduced fibrogenic properties in cultured hepatic stellate cells. Moreover, Ghrl-/- mice developed exacerbated hepatic fibrosis and liver damage after chronic injury. Ghrelin also protected rat livers from acute liver injury and reduced the extent of oxidative stress and the inflammatory response. In patients with chronic liver diseases, ghrelin serum levels decreased in those with advanced fibrosis and hepatic expression of the ghrelin gene correlated with expression of fibrogenic genes. Finally, in patients with chronic hepatitis C, single nucleotide polymorphisms of the ghrelin gene (-994CT and 604GA) influenced the progression of liver fibrosis. We conclude that ghrelin exerts antifibrotic effects on the liver and may represent a novel antifibrotic therapy.
Ghrelin attenuates hepatocellular injury and liver fibrogenesis in rodents and influences fibrosis progression in humans.
No sample metadata fields
View SamplesWhile genetic mutation is a hallmark of cancer, many cancers also acquire epigenetic alterations during tumorigenesis including aberrant DNA hypermethylation of tumor suppressors as well as changes in chromatin modifications as caused by genetic mutations of the chromatin-modifying machinery. However, the extent of epigenetic alterations in cancer cells has not been fully characterized. Here, we describe the first complete methylome maps at single nucleotide resolution of a low-passage breast cancer cell line and primary human mammary epithelial cells. We find widespread DNA hypomethylation in the cancer cell, primarily at partially methylated domains (PMDs) in normal breast cells. Unexpectedly, genes within these regions are largely silenced in cancer cells. The loss of DNA methylation in these regions is accompanied by formation of repressive chromatin, with a significant fraction displaying allelic DNA methylation where one allele is DNA methylated while the other allele is occupied by histone modifications H3K9me3 or H3K27me3. Our results show a mutually exclusive and complementary relationship between DNA methylation and H3K9me3 or H3K27me3. These results suggest that global DNA hypomethylation in breast cancer is tightly linked to the formation of repressive chromatin domains and gene silencing, thus identifying a potential epigenetic pathway for gene regulation in cancer cells and suggesting a possible new approach toward the development of cancer therapeutics. Overall design: mRNA-Seq of polyA-selected RNA from breast cancer HCC1954 and normal breast HMEC. 36 cycles of sequencing on Illumina platform.
Global DNA hypomethylation coupled to repressive chromatin domain formation and gene silencing in breast cancer.
No sample metadata fields
View SamplesAn autochthonous model of pancreatic ductal adenocarcinoma (PDA) permitted the analysis of why immunotherapy is ineffective in this human disease. Despite finding that PDA-bearing mice had cancer cell-specific CD8+ T cells, the mice, like human PDA patients, did not respond to two immunological checkpoint antagonists that promote the function of T cells, a-CTLA-4 and a-PD-L1. Immune control of PDA growth was achieved, however, by depleting carcinoma-associated fibroblasts (CAFs) that express Fibroblast Activation Protein (FAP). The depletion of the FAP+ stromal cell also uncovered the anti-tumor effects of a-CTLA-4 and a-PD-L1, indicating that its immune suppressive activity accounts for the failure of these T cell checkpoint antagonists. Three findings suggested that CXCL12 explained the overriding immunosuppression by the FAP+ cell: T cells were absent from regions of the tumor containing cancer cells; cancer cells were coated with the chemokine, CXCL12; and the FAP+ CAF was the principle source of CXCL12 in the tumor. Administering AMD3100, a CXCL12 receptor (CXCR4) inhibitor, induced rapid T cell accumulation among cancer cells, and acted synergistically with a-PD-L1 to selectively and greatly diminish cancer cells, identified by their loss-of-heterozygosity (LOH) of Trp53. The residual tumor was comprised only of pre-malignant epithelial cells and inflammatory cells. Thus, a single protein, CXCL12, from a single stromal cell type, the FAP+ CAF, may direct tumor immune evasion in a model of human PDA. Overall design: FAP+ cells were sorted from pancreatic ductal adenocarcinoma. Cells were isolated in duplicate experiments and these were analysed separately. These were compared separately to previously published publicly available CD4+ T-cell subset data (C57BL/6 mice and Foxp3-RFP mice (Line 8374) GEO accession GSE20898), and previously published FAP+ cell datasets (transgenic albino (Tyr-/-) C57BL/6 mouse, GEO accession GSE39438).
Targeting CXCL12 from FAP-expressing carcinoma-associated fibroblasts synergizes with anti-PD-L1 immunotherapy in pancreatic cancer.
Specimen part, Disease, Disease stage, Subject
View SamplesObjective: Alcoholic hepatitis (AH) is characterized by the expansion of ductular reaction (DR) cells and expression of liver progenitor cell (LPC) markers. The aim of this study was to identify the gene expression profile and associated genes of DR cells and to evaluate its weight in alcoholic disease progression. Design: KRT7+, KRT7- and total liver fractions were laser microdissected from liver biopsies (n=6) of patients with AH and whole transcriptome was sequenced. Gene signature was assessed in transcriptomic data from 41 patients with alcoholic liver disease. Pro-inflammatory profile was evaluated in tissue and serum samples and in human LPC organoids. Results: Transcriptome analysis of KRT7+ DR cells uncovered intrinsic gene pathways of DR and allowed identifying genes associated with DR expressed in AH. In addition, DR gene signature and associated genes correlated with disease progression and poor outcome in AH patients. Importantly, DR presented a pro-inflammatory profile with expression of CXC and CCL chemokines and was associated with infiltrating neutrophils. Moreover, LPC markers correlated with liver expression and circulating levels of inflammatory mediators. In vitro, human LPC organoids mimicked ductular reaction gene expression profile and produced chemokines. Moreover, LPC promoted neutrophil migration and enhanced their inflammatory profile. Conclusions: Here we report for the first time the gene expression signature of DR in AH and its association with disease progression. Functional and experimental analysis demonstrates that DR cells have a pro-inflammatory profile, and suggest their involvement in neutrophil recruitment and liver inflammatory response.
Ductular Reaction Cells Display an Inflammatory Profile and Recruit Neutrophils in Alcoholic Hepatitis.
Sex, Age, Specimen part, Disease, Disease stage, Cell line, Treatment, Race
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