The role of the transcription factor EB (TFEB) in the control of cellular functions, including in vascular bed, is mostly thought to be the regulation of lysosomal biogenesis and autophagic flux. While this is its best-known function, we report here the ability of TFEB to orchestrate a non-canonical program involved in the control of cell-cycle and VEGFR2 pathway in the developing vasculature. In endothelial cells, TFEB deletion halts proliferation by inhibiting the CDK4/Rb pathway, which regulates the cell cycle G1-S transition. In an attempt to overcome this limit, cells compensate by increasing the amount of VEGFR2 on the plasma membrane through a microRNA-mediated mechanism and the control of its membrane trafficking. TFEB transactivates the miR-15a/16-1 cluster, which limits the stability of the VEGFR2 transcript, and negatively modulates the expression of MYO1C, which regulates VEGFR2 delivery to the cell surface. In TFEB knocked-down cells, the reduced and increased amount respectively of miR-15a/16-1 and MYO1C result in the overexpression on plasmamembrane of VEGFR2, which however shows low signaling strength. Using endothelial loss-of-function Tfeb mouse mutants, we present evidence of defects in fetal and newborn mouse vasculature caused by the reduced endothelial proliferation and by the anomalous function of VEGFR2 pathway. Thus, this study revealed a new and unreported function of TFEB that expands its role beyond the regulation of autophagic pathway in the vascular system.
TFEB controls vascular development by regulating the proliferation of endothelial cells.
Cell line
View SamplesGastrocnemius muscle biopsies were obtained from 15 health older adults without peripheral artery disease (PAD), 20 PAD patients with intermittent claudication, and 16 patients with critical limb ischemia undergoing limb amputation. Gene expression analysis was performed using RNA sequencing analysis. Overall design: Examination of gene expression differences across the clinical spectrum of PAD (healthy vs. claudicant vs. critical limb ischemia)
Extensive skeletal muscle cell mitochondriopathy distinguishes critical limb ischemia patients from claudicants.
Specimen part, Disease, Subject
View SamplesThe goal of this set of experiments was to identify transcripts that are differentially expressed upon reactivation of NMD in an nmd2::HIS3 strain by galactose-induced expression of the NMD2 gene.
Association of yeast Upf1p with direct substrates of the NMD pathway.
No sample metadata fields
View SamplesThe activation of endothelium by tumor cells is one of the main steps by tumor metastasis. The role of the blood components (platelets and leukocytes) in this process remain unclear.
Selectin-mediated activation of endothelial cells induces expression of CCL5 and promotes metastasis through recruitment of monocytes.
Specimen part
View SamplesIn response to UVB irradiation, human keratinocytes transiently block cell cycle progression to allow ample time for DNA repair and cell fate determination. These cellular processes are important for evading the initiation of carcinogenesis in skin. We previously showed that repression of mRNA translation initiation through phosphorylation of eIF2a (eIF2a-P) protects keratinocytes from UVB-induced apoptosis. In this study, we elucidate the mechanism of eIF2a-P cytoprotection in response to UVB. Loss of eIF2a-P induced by UVB diminished G1 arrest, DNA repair rate, and cellular senescence coincident with enhanced cell death in human keratinocytes. Genome-wide translation analyses revealed that the mechanism for these critical changes directed by eIF2a-P involved induced expression of CDKN1A encoding p21 protein. p21 is a major regulator of the cell cycle, and we show that human CDKN1A mRNA splice variant 4 is preferentially translated by eIF2a-P during stress in a mechanism mediated in part by upstream ORFs situated in the 5'-leader of CDKN1A mRNA. We conclude that eIF2a-P is cytoprotective in response to UVB by a mechanism featuring translation of a specific splice variant of CDKN1A that facilitates G1 arrest and subsequent DNA repair. Overall design: Untreated and irradiated N-TERT keratinocytes are split into 3 groups: monosome fraction, polysome fraction, and whole cell lysate. N=3.
Translational control of a human <i>CDKN1A</i> mRNA splice variant regulates the fate of UVB-irradiated human keratinocytes.
Specimen part, Cell line, Treatment, Subject
View SamplesThe goal of this experiment was to identify transcripts associated with the S. cerevisiae Upf1 protein.
Association of yeast Upf1p with direct substrates of the NMD pathway.
No sample metadata fields
View SamplesUnderstanding the structure and interplay of cellular signalling pathways is one of the great challenges in molecular biology. Boolean Networks can infer signalling networks from observations of protein activation. In situations where it is difficult to assess protein activation directly, Nested Effect Models are an alternative. They derive the network structure indirectly from downstream effects of pathway perturbations. To date, Nested Effect Models cannot resolve signalling details like the formation of signalling complexes or the activation of proteins by multiple alternative input signals. Here we introduce Boolean Nested Effect Models (B-NEM). B-NEMs combine the use of downstream effects with the higher resolution of signalling pathway structures in Boolean Networks. We show that B-NEMs accurately reconstruct signal flows in simulated data. Using B-NEM we then resolve BCR signalling via PI3K and TAK1 kinases in BL2 lymphoma cell lines.
Analyzing synergistic and non-synergistic interactions in signalling pathways using Boolean Nested Effect Models.
Specimen part, Cell line, Treatment
View SamplesGenome-wide analysis of mRNAs regulated by the nonsense-mediated and 5' to 3' mRNA Decay Pathways in Yeast
Genome-wide analysis of mRNAs regulated by the nonsense-mediated and 5' to 3' mRNA decay pathways in yeast.
Sex
View SamplesTo determine the effects of inactivation of both the nosense-mediated mRNA decay pathway and the general 5' to 3' decay pathway on yeast mRNA decay, we compared the expression profiles of the wild-type, xrn1, xrn1 upf1, xrn1 nmd2, and xrn1 upf3 strains.
Genome-wide analysis of mRNAs regulated by the nonsense-mediated and 5' to 3' mRNA decay pathways in yeast.
Sex
View SamplesType 2 Diabetes, obesity and metabolic syndrome are pathologies impacting a large population worldwide where insulin resistance plays a central role. These pathologies are usually associated to a dysregulation of insulin secretion leading to a chronic exposure of the tissues to high insulin levels (i.e. hyperinsulinemia) what diminishes the concentration of key downstream elements causing insulin resistance. The complexity of the study of insulin resistance relies on the heterogeneity of the metabolic states where it’s observed. In consequence, animal models for the study of insulin resistance, can not completely recapitulate the metabolic status of insulin resistant humans, what is translated in contradictory observations. To contribute to the understanding of the mechanisms triggering insulin resistance we have developed a zebrafish model to study insulin metabolism and its associated disorders. Zebrafish embryos appeared to be sensitive to human recombinant insulin, becoming insulin resistant when exposed to a high dose of the hormone, as confirmed by glucose measurements. Moreover RNAseq-based transcriptomic profiling of these embryos revealed a strong down regulation of a number of immune relevant genes as a consequences of the exposure to hyperinsulinemia. Interestingly, as an exception, the negative immune modulator ptpn6 appeared to be up regulated in insulin resistant embryos. Knockdown of ptpn6 showed to counteract the observed down regulation of the immune system and insulin signalling pathways effects at the transcriptional level caused by hyperinsulinemia. These results show that ptpn6 is a mediator of the metabolic switch between insulin sensitive and insulin resistant states. Our zebrafish model for hyperinsulinemia has therefore demonstrated it suitability to discover novel regulators of insulin resistance. In addition, our data will be very useful to further study the function of immunological determinants in a non-obese model system. Overall design: 16 samples in total were analyzed. 4 replicates from control samples (injected with PBS) and 4 replicates of insulin injected samples at 0.5 hpi and 4 hpi. In each sample 10 embryos were pooled.
Hyperinsulinemia induces insulin resistance and immune suppression via Ptpn6/Shp1 in zebrafish.
No sample metadata fields
View Samples