Lymphatic endothelial cells were grown under normoxia, hypoxia (1% 0xygen) and conditioned medio from NSLCN growth under normoxia or hypoxia. Gene expression was measured and comparition between samples performed
Hypoxia alters the adhesive properties of lymphatic endothelial cells. A transcriptional and functional study.
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View SamplesBladder cancer (BC) is a highly prevalent human disease in which Rb pathway inactivation and epigenetic alterations are common events. However, the connection between these two processes is still poorly understood. Here we show that the in vivo inactivation of all Rb family genes in the mouse urothelium is sufficient to initiate BC development. The characterization of the mouse tumors revealed multiple molecular features of human BC, including the activation of E2F transcription factor and subsequent Ezh2 expression, and the activation of several signaling pathways previously identified as highly relevant in urothelial tumors. Whole transcriptional characterizations of the mouse bladder tumors revealed a significant overlap with human BC samples, and a predominant role for Ezh2 in the downregulation of gene expression programs. Importantly, we determined that in human superficial BC patients, the increased tumor recurrence and progression in these recurrences is associated with increased E2F and Ezh2 expression and Ezh2-mediated gene expression repression. Collectively, our studies provide a genetically defined model for human high-grade superficial BC and demonstrate the existence of an Rb-E2F-Ezh2 axis in bladder whose disruption can promote tumor development.
In vivo disruption of an Rb-E2F-Ezh2 signaling loop causes bladder cancer.
Specimen part, Disease, Treatment
View SamplesThe specific deletion of Rb gene in epidermis leads to altered proliferation and differentiation, but not to the development of spontaneous tumors. Our previous data have demonstrated the existence of a functional compensation of Rb loss by Rbl1 (p107) in as the phenotypic differences with respect to controls are intensified. However, the possible evolution of this aggravated phenotype, in particular in relationship with tumorigenesis, has not been evaluated due to the premature death of the double deficient mice. We have now investigated whether p107 can also act as a tumor suppressor in pRb-deficient epidermis using different experimental approaches. We found spontaneous tumor development in doubly-deficient skin grafts. Moreover, Rb-deficient keratinocytes are susceptible to Ha-ras-induced transformation, and this susceptibility is enhanced by p107 loss. Further functional analyses, including microarray gene expression profiling, indicated that the loss of p107, in the absence of pRb, produces the reduction of p53-dependent pro-apoptotic signals. Overall, our data demonstrate that p107 behaves as a tumor suppressor in epidermis in the absence of pRb and suggest novel tumor-suppressive roles for p107 in the context of functional p53 and activated Ras
p107 acts as a tumor suppressor in pRb-deficient epidermis.
Specimen part
View SamplesAim: To determine the role of NOTCH during the response-to-injury and subsequent chronic inflammatory process of the arterial wall underlying atherosclerosis. Methods and results: We have generated an endothelial-specific RBPJK depleted mice using the Cdh5 cadherin promoter (ApoE-/-;RBPJflox/flox;Cdh5- CreERT). Endothelial-specific deletion of the Notch effector RBPJK or systemic deletion of the Notch1 receptor in athero-susceptible ApoE-/- mice fed a HC diet for 6 weeks resulted in reduced atherosclerosis in the aortic arch and sinus. Intravital microscopy revealed decreased leukocyte rolling on the endothelium of ApoE-/-;RBPJflox/flox;Cdh5- CreERT, that correlated with the lesser presence of leukocyts and macrophages in the vascular wall. Consistent with this, transcriptome analysis revealed that proinflammatory and endothelial activation pathways were downregulated in atherosclerotic tissue of RBPJk-mutant mice.. Jagged1 signaling upregulation in endothelial cells promotes the physical interaction and nuclear translocation of the intracellular domain of the Notch1 receptor (N1ICD) with NF-kB,. This N1ICD and NF-kB interaction is required for reciprocal transactivation of target genes including vascular cell adhesion molecule-1 (Vcam1). Conclusions: Notch signaling pathway inactivation decreases leukocyte rolling, thereby preventing endothelial dysfunction and vascular inflammation. Thus attenuating Notch signaling may constitute a useful therapeutic strategy for atherosclerosis. Key words: atherosclerosis, endothelium, signaling pathways, Notch, NF-kB, transcriptional regulation Overall design: RNA was isolated from the aortic arches of three ApoE-/-;RBPJflox/flox and three ApoE-/-; RBPJflox/flox;Cdh5-CreERTmice
Endothelial Jag1-RBPJ signalling promotes inflammatory leucocyte recruitment and atherosclerosis.
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View SamplesCxcr7-/- mice die a few hours after birth. All of them display semilunar valves abnormalities, including bicuspid aortic or pulmonary valves. Those defects only become obvious before birth.
Disrupted cardiac development but normal hematopoiesis in mice deficient in the second CXCL12/SDF-1 receptor, CXCR7.
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View SamplesWe have characterized a mutation affecting the Arabidopsis EARLY IN SHORT DAYS 7 (ESD7) gene encoding the catalytic subunit of the DNA polymerase epsilon (e), AtPOL2A. esd7-1 mutations causes early flowering independently of photoperiod, shortened inflorescence internodes and altered leaf and root development. esd7-1 was a hypomorphic allele whereas KO alleles displayed an embryo-lethal phenotype. The SAM and the RAM in the esd7-1 seedlings were found to exhibit an altered disposition that might correlate with the abnormal expression pattern of SAM and RAM marker genes. esd7-1 showed higher sensitivity to DNA damaging reagents than wild type plants and altered expression of genes involved in DNA repair mechanisms by homologous recombination. Moreover, esd7 early flowering phenotype requires functional FT and SOC1 proteins and might be also related to the mis-regulation of AG and AG-like gene expression found in esd7. Loci involved in the modulation of the chromatin structural dynamics, such as TFL2 and EBS, which negatively regulate FT expression, were found to interact genetically with ESD7, and the carboxy terminus of ESD7 interacted with TFL2 in vitro. Besides, fasciata2 (fas2) mutations suppressed esd7 early flowering phenotype and INCURVATA 2 (ICU2) was found to be epistatic to ESD7. Discrete regions of the chromatin of FT and AG loci were enriched in activating epigenetic marks in the esd7-1 mutant. We concluded that ESD7 might be participating in processes involved in chromatin-mediated cellular memory.
EARLY IN SHORT DAYS 7 (ESD7) encodes the catalytic subunit of DNA polymerase epsilon and is required for flowering repression through a mechanism involving epigenetic gene silencing.
Specimen part
View SamplesWe used microarrays to investigate gene expression changes in human colon normal fibroblasts exposed to a bitter orange extract enriched in flavanones (and previously subjected to in vitro gastro-duodenal digestion) to determine possible modulatory beneficial effects induced by these plant-derived compounds on the colon cells.
A citrus extract containing flavanones represses plasminogen activator inhibitor-1 (PAI-1) expression and regulates multiple inflammatory, tissue repair, and fibrosis genes in human colon fibroblasts.
Specimen part, Cell line, Treatment
View SamplesUpon antigen recognition within peripheral lymphoid organs, B cells interact with T cells and other immune cells to transiently form morphological structures called germinal centers (GCs), which are required for B cells clonal expansion, immunoglobulin class switching, and affinity maturation. This process, known as the GC response, is an energetically demanding process that requires metabolic reprogramming of B cells. Here, we showed that the Ras-related guanosine triphosphate hydrolase (GTPase) R-Ras2 (also known as TC21) plays an essential, nonredundant, and B cellintrinsic role in the GC response. Both the conversion of B cells into GC B cells and their expansion were impaired in mice lacking R-Ras2, but not in those lacking a highly-related R-Ras subfamily member or both the classic H-Ras and N-Ras GTPases. In the absence of R-Ras2, activated B cells did not increase oxidative phosphorylation or aerobic glycolysis. We showed that R-Ras2 was an effector of both the B cell receptor (BCR) and CD40 and that, in its absence, B cells exhibited impaired activation of the PI3K-Akt-mTORC1 pathway, reduced mitochondrial DNA replication, and decreased expression of genes involved in glucose metabolism. Because most human B cell lymphomas originate from GC B cells or B cells that have undergone the GC response, our data suggests that R-Ras2 may also regulate metabolism in B cell malignancies.
R-Ras2 is required for germinal center formation to aid B cells during energetically demanding processes.
Specimen part
View SamplesE2F/RB activity is altered in most human tumors. The retinoblastoma family of proteins plays a key role in regulating the progression of the cell cycle from the G1 to S phases. This is achieved through negative regulation of E2F transcription factors, important positive regulators of cell cycle entry. E2F family members are divided in two groups: activators (E2F1-E2F3a) and repressors (E2F3b-E2F8). E2F4 accounts for a large part of the E2F activity and is a main E2F repressor member in vivo. Perturbations in the balance from quiescence towards proliferation contribute to increased mitotic gene expression levels frequently observed in cancer. We have previously reported that combined Rb1-Rbl1 and Rb1-E2F1 ablation in epidermis produces important alterations in epidermal proliferation and differentiation, leading to tumor development. However, the possible roles of E2F4 in this context are still to be determined. Here we show the absence of any discernible phenotype in the skin of mice lacking of E2F4. In contrast, the inducible loss of Rb1 in the epidermis of E2F4-null mice produced multiple skin abnormalities including altered differentiation and proliferation, spontaneous wounds, carcinoma in situ development and stem cell perturbations. All these phenotypic alterations are associated with extensive gene expression changes, the induction of c-myc and the Akt activation. Moreover, the whole transcriptome analyses in comparison with previous models generated also revealed extensive changes in multiple repressive complexes and in transcription factor activity. These results point to E2F4 as a master regulator in multiple steps of epidermal homeostasis in Rb1 absence.
Deregulation of the pRb-E2F4 axis alters epidermal homeostasis and favors tumor development.
Specimen part
View SamplesThe specific ablation of Rb1 gene in epidermis (RbF/F;K14cre) promotes proliferation and altered differentiation but does not produce spontaneous tumour development. These phenotypic changes are associated with increased expression of E2F members and E2F-dependent transcriptional activity. Here, we have focused on the possible dependence on E2F1 gene function. We have generated mice that lack Rb1 in epidermis in an inducible manner (RbF/F;K14creERTM). These mice are indistinguishable from those lacking pRb in this tissue in a constitutive manner (RbF/F;K14cre). In an E2F1-null background (RbF/F;K14creERTM; E2F1-/- mice), the phenotype due to acute Rb1 loss is not ameliorated by E2F1 loss, but rather exacerbated, indicating that pRb functions in epidermis do not rely solely on E2F1. On the other hand, RbF/F;K14creERTM;E2F1-/- mice develope spontaneous epidermal tumours of hair follicle origin with high incidence. These tumours, which retain a functional p19arf/p53 axis, also show aberrant activation of catenin/Wnt pathway. Gene expression studies revealed that these tumours display relevant similarities with specific human tumours. These data demonstrate that the Rb/E2F1 axis exerts essential functions not only in maintaining epidermal homeostasis, but also in suppressing tumour development in epidermis, and that the disruption of this pathway may induce tumour progression through specific alteration of developmental programs.
E2F1 loss induces spontaneous tumour development in Rb-deficient epidermis.
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