Effects of the prop-1 and Ghrhr mutations in gene expression during normal aging in mice.
Gene expression profile of long-lived Ames dwarf mice and Little mice.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesGender-specific alterations in gene expression and loss of liver sexual dimorphism in the long-lived Ames dwarf mice.
Gender-specific alterations in gene expression and loss of liver sexual dimorphism in the long-lived Ames dwarf mice.
Sex, Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Elevated interferon gamma signaling contributes to impaired regeneration in the aged liver.
Sex, Treatment
View SamplesThe process of liver regeneration can be divided into a series of stages that include initial inductive or priming events through cellular mitosis. Following two-thirds liver resection, the liver undergoes the priming phase, in which cytokines TNF-a and IL-6 activate their respective receptors in hepatocytes. This leads to the activation of several key transcription factors: NF-kB, AP-1, Stat 3, Stat 1, and C/EBP-b and -d . These transcription factors induce the expression of immediate early genes. HGF is also expressed at this time and involved in the transition of quiescent hepatocytes into the G1 phase of the cell cycle. During the G1 phase, delayed early genes are expressed followed by induction of cell cyclerelated genes, both of which require new protein synthesis for their production. Increased expression of FoxM1B and TGF-a occurs at the G1/S transition and is correlated with increased expression of cyclinD1 and decreased expression of cdk inhibitors. During the G2/M phase of the cell cycle, FoxM1B directly elevates cyclinB1, cyclinB2, and cdc25B expression. Additionally, FoxM1B is associated with increased cyclinF and p55cdc, which are involved in completion of the cell cycle following partial hepatectomy. In mice, two-thirds partial hepatectomy promotes proliferation of liver cells and rapid growth of the remaining liver tissue, resulting in complete restoration of organ mass in approximately 7 days (Mackey S. et al. Hepatology 2003 Dec;38(6):1349-52).
Elevated interferon gamma signaling contributes to impaired regeneration in the aged liver.
Sex, Treatment
View SamplesThe process of liver regeneration can be divided into a series of stages that include initial inductive or priming events through cellular mitosis. Following two-thirds liver resection, the liver undergoes the priming phase, in which cytokines TNF-a and IL-6 activate their respective receptors in hepatocytes. This leads to the activation of several key transcription factors: NF-kB, AP-1, Stat 3, Stat 1, and C/EBP-b and -d . These transcription factors induce the expression of immediate early genes. HGF is also expressed at this time and involved in the transition of quiescent hepatocytes into the G1 phase of the cell cycle. During the G1 phase, delayed early genes are expressed followed by induction of cell cyclerelated genes, both of which require new protein synthesis for their production. Increased expression of FoxM1B and TGF-a occurs at the G1/S transition and is correlated with increased expression of cyclinD1 and decreased expression of cdk inhibitors. During the G2/M phase of the cell cycle, FoxM1B directly elevates cyclinB1, cyclinB2, and cdc25B expression. Additionally, FoxM1B is associated with increased cyclinF and p55cdc, which are involved in completion of the cell cycle following partial hepatectomy. In mice, two-thirds partial hepatectomy promotes proliferation of liver cells and rapid growth of the remaining liver tissue, resulting in complete restoration of organ mass in approximately 7 days (Mackey S. et al. Hepatology 2003 Dec;38(6):1349-52).
Elevated interferon gamma signaling contributes to impaired regeneration in the aged liver.
Sex, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcriptional profiling of bipotential embryonic liver cells to identify liver progenitor cell surface markers.
Specimen part, Cell line
View SamplesPromoter hypermethylation and transcriptional silencing is a common epigenetic mechanism of tumour suppressor inactivation in cancer, including malignant brain tumours.
Epigenetic genome-wide analysis identifies BEX1 as a candidate tumour suppressor gene in paediatric intracranial ependymoma.
Specimen part, Treatment
View SamplesThe ability to purify to homogeneity a population of hepatic progenitor cells from adult liver is critical for their characterization prior to any therapeutic application. As a step in this direction, we have utilized gene profiling of a bipotential liver cell line from dpc 14 mouse embryonic liver to catalog genes expressed by liver progenitor cells. These cells, known as Bipotential Mouse Embryonic Liver (BMEL) cells, proliferate in an undifferentiated state and are capable of differentiating into hepatocyte-like and cholangiocyte-like cells in vitro. Upon transplantation, BMEL cells are capable of differentiating into hepatocytes and cholangiocytes in vivo. Microarray analysis of gene expression in the 9A1 and 14B3 BMEL cell lines grown under proliferating and differentiating conditions was used to identify cell surface markers preferentially expressed in the bipotential undifferentiated state. This analysis revealed that proliferating BMEL cells express many genes involved in cell cycle regulation whereas differentiation of BMEL cells by cell aggregation causes a switch in gene expression to functions characteristic of mature hepatocytes. In addition, microarray data and protein analysis indicated that the Notch signaling pathway could be involved in maintaining BMEL cells in an undifferentiated stem cell state. Using GO annotation, a list of cell surface markers preferentially expressed on undifferentiated BMEL cells was generated. One marker, Cd24a, is specifically expressed on progenitor oval cells in livers of DDC treated animals. We therefore consider Cd24a expression a candidate molecule for purification of hepatic progenitor cells.
Transcriptional profiling of bipotential embryonic liver cells to identify liver progenitor cell surface markers.
Specimen part, Cell line
View SamplesThe ability to purify to homogeneity a population of hepatic progenitor cells from adult liver is critical for their characterization prior to any therapeutic application. As a step in this direction, we have utilized gene profiling of a bipotential liver cell line from dpc 14 mouse embryonic liver to catalog genes expressed by liver progenitor cells. These cells, known as Bipotential Mouse Embryonic Liver (BMEL) cells, proliferate in an undifferentiated state and are capable of differentiating into hepatocyte-like and cholangiocyte-like cells in vitro. Upon transplantation, BMEL cells are capable of differentiating into hepatocytes and cholangiocytes in vivo. Microarray analysis of gene expression in the 9A1 and 14B3 BMEL cell lines grown under proliferating and differentiating conditions was used to identify cell surface markers preferentially expressed in the bipotential undifferentiated state. This analysis revealed that proliferating BMEL cells express many genes involved in cell cycle regulation whereas differentiation of BMEL cells by cell aggregation causes a switch in gene expression to functions characteristic of mature hepatocytes. In addition, microarray data and protein analysis indicated that the Notch signaling pathway could be involved in maintaining BMEL cells in an undifferentiated stem cell state. Using GO annotation, a list of cell surface markers preferentially expressed on undifferentiated BMEL cells was generated. One marker, Cd24a, is specifically expressed on progenitor oval cells in livers of DDC treated animals. We therefore consider Cd24a expression a candidate molecule for purification of hepatic progenitor cells.
Transcriptional profiling of bipotential embryonic liver cells to identify liver progenitor cell surface markers.
Specimen part, Cell line
View SamplesPatients with tuberous sclerosis complex (TSC) develop hamartomas containing biallelic inactivating mutations in either TSC1 or TSC2, resulting in mammalian target of rapamycin (mTOR) activation. Hamartomas overgrow epithelial and mesenchymal cells in TSC skin. The pathogenetic mechanisms for these changes had not been investigated, and the existence or location of cells with biallelic mutations (two-hit cells) that resulted in mTOR activation was unclear. We compared TSC skin hamartomas (facial angiofibromas and periungual fibromas) to normal-appearing skin of the same patient, and observed more proliferation and mTOR activation in hamartoma epidermis. Two-hit cells were not detected in the epidermis. Fibroblast-like cells in the dermis, however, exhibited allelic deletion of TSC2, in both touch preparations of fresh tumor samples and cells grown from TSC skin tumors, suggesting that increased epidermal proliferation and mTOR activation were not caused by second-hit mutations in the keratinocytes but by mesenchymal-epithelial interactions. Gene expression arrays, used to identify potential paracrine factors released by mesenchymal cells, revealed more epiregulin mRNA in fibroblast-like angiofibroma and periungual fibroma cells than in fibroblasts from normal-appearing skin of the same patient. Elevation of epiregulin mRNA was confirmed using real-time PCR, and increased amounts of epiregulin protein were demonstrated using immunoprecipitation and ELISA. Epiregulin stimulated keratinocyte proliferation and phosphorylation of ribosomal protein S6 in vitro. These results suggest that hamartomatous TSC skin tumors are induced by paracrine factors released by two-hit cells in the dermis, and that proliferation with mTOR activation of the overlying epidermis is an effect of epiregulin.
Mesenchymal-epithelial interactions involving epiregulin in tuberous sclerosis complex hamartomas.
Sex, Specimen part
View Samples