Project description:Transcription factro-EB (TFEB) is a master gene for autophagy and lysosome biogenesis We used microarrays to detail the gene expression in TFEB-overexpressing endothelial cells and identified distinct classes of TFEB-regulated genes.
Project description:Transcription factro-EB (TFEB) is a master gene for autophagy and lysosome biogenesis We used microarrays to detail the gene expression in TFEB-overexpressing vascular smooth muscle cells identified distinct classes of TFEB-regulated genes.
Project description: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.
Project description: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.
Project description:Mammalian target of rapamycin (mTOR) complex 1 (mTORC1) is a critical regulator of cell growth by integrating multiple signals (nutrients, growth factors, energy and stress) and is frequently deregulated in many types of cancer. We used a robust experimental paradigm involving the combination of two interventions, one genetic and one pharmacologic to identify genes regulated transcriptionally by mTORC1. In Tsc2+/+, but not Tsc2-/- immortalized mouse embryo fibroblasts (MEFs), serum deprivation downregulates mTORC1 activity. In Tsc2-/- cells, abnormal mTORC1 activity can be downregulated by treatment with rapamycin (sirolimus). By contrast, rapamycin has little effect on mTORC1 in Tsc2+/+ cells in which mTORC1 is already inhibited by low serum. Thus, under serum deprived conditions, mTORC1 activity is low in Tsc2+/+ cells (untreated or rapamycin treated), high in Tsc2-/- cells, but lowered by rapamycin; a pattern referred to as a M-bM-^@M-^\low/low/high/lowM-bM-^@M-^] or M-bM-^@M-^\LLHLM-bM-^@M-^]. We found that mTORC1 regulated the expression of, among other lysosomal genes, V-ATPases through the transcription factor EB (TFEB, Tcfeb in the mouse). The knockdown of Tfeb resulted in the 'flattening' of the LLHL pattern and allowed the identification of genes regulated by mTORC1 through Tfeb Mouse embryo fibroblasts (MEFs) wild type or deficient in Tsc2 expressing a Tfeb shRNA or scrambled shRNA vector were treated with 25 nM rapamycin or vehicle (methanol) for 24 h under low serum conditions (0.1% FBS)
Project description:The largest germinal niche of the adult mammal brain locates at the ventricular zone (VZ), which is made up of adult neural stem cells (NSCs) and multiciliated ependymal cells (EPCs). Both NSCs and EPCs derive from radial glia (RG), whereas the transcriptomic dynamic changes of the cell fate continuum remain elusive. Here, we identified a key transcription factor TFEB that is important during EPC differentiation. We knockdown TFEB using siRNA and check gene expression changes upon TFEB depletion by RNA-seq.
Project description:To determine whether endothelial TFEB is critical for glucose metabolism in vivo, we utilized EC-selective TFEB knockout mice and EC selective TFEB transgenic mice fed a high fat diet (HFD). EC-TFEB knockout mice exhibited significantly impaired glucose tolerance compared with control mice. Consistently, EC-TFEB transgenic mice showed improved glucose intolerance. In primary human ECs, small interfering RNA-mediated TFEB knockdown blunts the Akt signaling. adenovirus-mediated overexpression of TFEB consistently activates Akt signaling and significantly increases glucose uptake in ECs. Mechanically, TFEB upregulates insulin receptor substrate 1 and 2 (IRS1 and IRS2). TFEB increases IRS2 transcription measured by reporter gene and chromatin immunoprecipitation assays. Furthermore, we found that TFEB increases IRS1 protein via downregulation of microRNAs (miR-335, miR-495 and miR548o). In vivo, Akt signaling in the skeletal muscle and adipose tissue was significantly impaired in EC-TFEB knockout mice and consistently improved in EC-TFEB transgenic mice on HFD
Project description: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.