Both cellular senescence and organismic aging are known to be dynamic processes that start early in life and progress constantly during the whole life of the individual. In this work, with the objective of identifying signatures of age-related progressive change at the transcriptomic level, we have performed a whole-genome gene expression analysis of peripheral blood leukocytes in a group of healthy individuals with ages ranging from 14 to 93 years. A set of genes with progressively changing gene expression (either increase or decrease with age) has been identified and contextualized in a coexpression network. A modularity analysis has been performed on this network and biological-term and pathway enrichment analyses have been used for biological interpretation of each module. In summary, the results of the present work reveal the existence of a transcriptomic component that shows progressive expression changes associated to age in peripheral blood leukocytes, highlighting both the dynamic nature of the process and the need to complement young vs. elder studies with longitudinal studies that includes middle aged individuals. From the transcriptional point of view, immunosenescence seems to be occurring from a relatively early age, at least from the late 20s/early 30s, and the 49 56 y/o age-range appears to be critical. In general, the genes that, according to our results, show progressive expression changes with aging are involved in pathogenic/cellular processes that have classically been linked to aging in humans: cancer, immune processes and cellular growth vs. maintenance.
Age gene expression and coexpression progressive signatures in peripheral blood leukocytes.
Age, Specimen part
View SamplesThe Wilms tumor 1 gene (WT1) encodes a transcription factor involved in cell growth and development. As we previously reported WT1 expression is hardly detectable in normal hepatic tissue but is induced in liver cirrhosis. Although WT1 has been found to be overexpressed in a number of malignancies, the role of WT1 in hepatocarcinogenesis has not been clarified. We found that WT1 is expressed in several human hepatocellular carcinoma (HCC) cell lines including PLC/PRF/5 and HepG2, and in HCC tumor tissue in 42% of patients. WT1 small interfering RNAs did not affect proliferation rate of HCC cells but abrogated their resistance to anoikis. Transcriptome analysis of PLC/PRF/5 cells after WT1 knockdown demonstrated upregulation of 251 genes and downregulation of 321. Ninety per cent of the former corresponded to metabolic genes mostly those characterizing the mature hepatocyte phenotype. On the contrary, genes that decreased upon WT1 inhibition were mainly related to defense against apoptosis, cell cycle and tumor progression. In agreement with these findings WT1 expression increased the resistance of liver tumor cells to doxorubicin, a compound used to treat HCC. Interestingly, doxorubicin strongly enhanced WT1 expression in both HCC cells and normal human hepatocytes. Among different chemotherapeutics, induction of WT1 transcription was restricted to topoisomerase 2 inhibitors. When WT1 expression was prohibited doxorubicin caused a marked increase in caspase-3 activation. In conclusion, WT1 is expressed in a substantial proportion of HCC contributing to tumor progression and resistance to chemotherapy, suggesting that WT1 may be an important target for HCC treatment.
Wilms' tumor 1 gene expression in hepatocellular carcinoma promotes cell dedifferentiation and resistance to chemotherapy.
No sample metadata fields
View SamplesThe equilibrium between cellular differentiation and proliferation is fundamental for tissue homeostasis. This is particularly important for the liver, a highly differentiated organ with systemic metabolic functions still endowed with unparalleled regenerative potential. Hepatocellular de-differentiation and uncontrolled proliferation are at the basis of liver carcinogenesis. We have identified SLU7, a pre-mRNA splicing regulator inhibited in hepatocarcinoma as a pivotal gene for hepatocellular homeostasis. SLU7 knockdown in human liver cells and mouse liver resulted in profound changes in pre-mRNA splicing and gene expression, leading to impaired glucose and lipid metabolism, refractoriness to key metabolic hormones, and reversion to a fetal-like gene expression pattern. Hepatocellular proliferation and a switch to a tumor-like glycolytic phenotype were also observed. Mechanistically, SLU7 governed the splicing and/or expression of essential genes for hepatocellular differentiation like SRSF3 and HNF4a, and was identified as a critical factor in cAMP-regulated gene transcription. SLU7 is therefore central for hepatocyte identity and quiescence.
Splicing regulator SLU7 is essential for maintaining liver homeostasis.
Cell line
View SamplesObesity is a major risk factor for metabolic disorders like insulin resistance and diabetes. We previously identified GPS2 as a clinical relavant repressor of metaflammation. No animal KO models were used to study its physiological function in vivo. The role of GPS2 in macrophage activation and inflammation is also largely unknown.
Loss of the co-repressor GPS2 sensitizes macrophage activation upon metabolic stress induced by obesity and type 2 diabetes.
Sex
View SamplesLiver X Receptors (LXRa and ß) are ligand-activated transcription factors that play a key role in the control of lipid homeostasis, as well as modulation of immunity and inflammation. LXR activity can be regulated by posttranslational modifications, such as phosphorylation. This study aims to assess changes in the hepatic transcriptional profiles of mice that carry a whole-body phosphorylation deficient knock in mutant of LXRa (S196A) compared to wild-type (WT) upon being fed a HFHC diet. Overall design: Liver mRNA profiles of either wild-type (WT) or LXRa-S196A female mice after being fed a High Fat-High Cholesterol diet for 6 weeks. Three biological replicate samples for each group are included. WT samples are used as controls.
Impaired LXRα Phosphorylation Attenuates Progression of Fatty Liver Disease.
Sex, Specimen part, Cell line, Subject
View SamplesLiver X Receptors (LXRa and ß) are ligand-activated transcription factors that play a key role in the control of lipid homeostasis, as well as modulation of immunity and inflammation. LXR activity can be regulated by posttranslational modifications, such as phosphorylation. This study aims to assess changes in the hepatic transcriptional profiles of mice that carry a whole-body phosphorylation deficient knock in mutant of LXRa (S196A) compared to wild-type (WT) fed a chow diet. Overall design: Liver mRNA profiles of either wild-type (WT) or LXRa-S196A 16-week old female mice on a chow diet. Three biological replicate samples for each group are included. WT samples are used as controls.
Impaired LXRα Phosphorylation Attenuates Progression of Fatty Liver Disease.
Specimen part, Cell line, Subject
View Samples