Project description:The p53 protein is a cell-autonomous tumor suppressor that restricts malignant transformation by triggering cell cycle exit or apoptosis. p53 also promotes cellular senescence, a program that triggers a stable cell cycle arrest and can modify the tissue microenvironment through its effect on cell membrane and secretory proteins. Here we show that specific ablation of p53 in hepatic stellate cells, which undergo a process of proliferation and senescence in the fibrogenic response to liver damage, enhances liver cirrhosis, reduces survival and increases the malignant transformation of adjacent epithelial cells into hepatocellular carcinoma. This p53-dependent senescence program involves the release of secreted proteins which skew macrophages into a tumor-inhibiting M1-state that can eliminate senescent stellate cells. In contrast, p53-deficient stellate cells secrete factors that promote M2 polarization, which is pro-tumorigenic. Our study reveals that p53 can exert a non-cell-autonomous tumor suppressor response and suggests that this occurs, in part, by its ability to influence macrophage polarization. We used microarrays to detail the global programme of gene expression underlying p53-dependent senescent and identified distinct classes of up-regulated or down-regulated genes during this process. Proliferating and senescent stellate cell pellets were collected RNA extraction and hybridization on Affymetrix microarrays.
Project description:Sex differences in liver gene expression are dictated by sex-differences in circulating growth hormone (GH) profiles. Presently, the pituitary hormone dependence of mouse liver gene expression was investigated on a global scale to discover sex-specific early GH response genes that might contribute to sex-specific regulation of downstream GH targets and to ascertain whether intrinsic sex-differences characterize hepatic responses to plasma GH stimulation. RNA expression analysis using 41,000-feature microarrays revealed two distinct classes of sex-specific mouse liver genes: genes subject to positive regulation (class-I) and genes subject to negative regulation by pituitary hormones (class-II). Genes activated or repressed in hypophysectomized (Hypox) mouse liver within 30-90min of GH pulse treatment at a physiological dose were identified as direct targets of GH action (early response genes). Intrinsic sex-differences in the GH responsiveness of a subset of these early response genes were observed. Notably, 45 male-specific genes, including five encoding transcriptional regulators that may mediate downstream sex-specific transcriptional responses, were rapidly induced by GH (within 30min) in Hypox male but not Hypox female mouse liver. The early GH response genes were enriched in 29 male-specific targets of the transcription factor Mef2, whose activation in hepatic stellate cells is associated with liver fibrosis leading to hepatocellular carcinoma, a male-predominant disease. Thus, the rapid activation by GH pulses of certain sex-specific genes is modulated by intrinsic sex-specific factors, which may be associated with prior hormone exposure (epigenetic mechanisms) or genetic factors that are pituitary-independent, and could contribute to sex-differences in predisposition to liver cancer or other hepatic pathophysiologies.
Project description:Cellular senescence is an irreversible proliferative arrest and can be triggered in many cell types in response to diverse forms of cellular damage or stress. We used microarrays to compare gene expression profile between growing and senescent human activated hepatic stellate cells. Experiment Overall Design: Two separate preparation of activated hepatic stellate cells were treated with DNA damaging agent to induce senescence or vechicle to remain growing. Experiment Overall Design: RNA was extracted from both replications and used for hybridization on Affymetrix arrays to determine expression differences.
Project description:Acute Pten loss initiates prostate tumorigenesis characterized by cellular senescence response. Here we examine the cellular senescence response in epithelial individual cells, by single-cell RNA sequencing (scRNAseq) in Ptenpc-/- and Ptenpc-/-; Timp1-/- GEMMs. ScRNAseq analysis determines a cluster of senescent cells expressing the senescence-related genes. A significant positive correlation is observed between the senescence score and Bcl2 expression. This provides the rational for targeting senescent cells using Bcl2 inhibitor.
Project description:Hepatic stellate cells are involved in the development of hepatic fibrosis. We here perform transcriptional profiling of hepatic stellate cells (HSCs) isolated from Western diet/high fructose-fed C57BL6/J mice, carbon tretrachloride (CCl4)-treated C57BL6/J mice, and of murine HSCs differentiated in vitro. Specifically, gene expression profiles are obtained from hepatic stellate cells isolated from C57BL6 mice fed a Western Diet supplemented with high fructose for 12, 16 or 24 weeks or normal chow. From hepatic stellate cells isolated from C57BL6 mice treated CCl4 for 1, 4 or 8 weeks or treated with vehicle. From hepatic stellate cells isolated from healthy C57BL6 mice and seeded on normal plastic cell culture dishes for 1, 4, 8, or 12 days. And from hepatic stellate cells isolated from healthy C57BL6 mice and seeded on normal plastic cell culture dishes for 6 days in the presence of 10uM U0126 or DMSO.