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: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:Paladin (Pald1, mKIAA1274 or x99384) was identified in screens for vascular-specific genes and is a putative phosphatase. We have demonstrated that paladin has a predominant vascular expression pattern and shifts from endothelial to mural cells during mouse development. We have now characterized the Pald1 knock-out mouse in a broad array of behavioral, physiological and biochemical tests. Here, we show that female, but not male, Pald1 heterozygous and homozygous knock-out mice displayed an emphysema-like phenotype with increased alveolar air spaces and impaired lung function with obstructive changes. In contrast to many other tissues where Pald1 is restricted to the vascular compartment, Pald1 is expressed in both the epithelial and mesenchymal compartments of the postnatal lung. However, in Pald1 knock-out females, there is a specific increase in apoptosis and proliferation of endothelial cells, but not in non-endothelial cells. This results in a transient reduction of endothelial cells in the maturing lung. Our data suggests that paladin is required during lung vascular development and for normal function of the developing and adult lung in a sex-specific manner. To our knowledge, this is the first report of a sex-specific effect on endothelial cell apoptosis.
Proteomic analysis of Pald1 wild type and knock-out mice reveal that most of the protein expression differences are related to sex and not genotype, supporting the notion that sex can be a major factor for lung development and disease. In addition, Pald1 wild type and knock-out mice exhibit differential expression of HPGD, hydroxyprostaglandin dehydrogenase 15 (NAD), the major enzyme for degradation of prostaglandins.
Project description:Vascular development involves complex changes in gene expression necessary to dictate the behaviour of differentiating endothelial cells within the emerging vascular network. However, the transcriptional programs regulating vascular development are poorly understood. Here we use a DamID approach to profile for the first time the global DNA binding pattern of SOX7, FLI1 and ERG in endothelial precursor cells. We uncover that SOX7, FLI1 and ERG bind together at endothelial specific regulatory regions to drive a transcriptional program important for vascular development.
Project description:Strict regulation of proliferation is vital for development, whereas unregulated cell proliferation is a fundamental characteristic of cancer. The polarity protein atypical protein kinase C lambda/iota (aPKC lambda) is associated with cell proliferation through unknown mechanisms. In endothelial cells, suppression of aPKC lambda impairs proliferation despite hyperactivated mitogenic signaling. Here we show that aPKC lambda phosphorylates the DNA binding domain of forkhead box O1 (FoxO1) transcription factor, a gatekeeper of endothelial growth. Although mitogenic signaling excludes FoxO1 from the nucleus, consequently increasing c-Myc abundance and proliferation, aPKC lambda controls c-Myc expression via FoxO1/miR-34c signaling without affecting its localization. We find this pathway is strongly activated in the malignant vascular sarcoma, angiosarcoma, and aPKC inhibition reduces c-Myc expression and proliferation of angiosarcoma cells. Moreover, FoxO1 phosphorylation at Ser218 and aPKC expression correlates with poor patient prognosis. Our findings may provide a new therapeutic strategy for treatment of malignant cancers, like angiosarcoma.
Project description:Increased level of angiotensin II (Ang II) plays a central role in the development of hypertensive vascular remodeling. Here, we identify the deubiquitinating enzyme JOSD2 as a protective factor and investigate its molecular mechanism in Ang II-induced vascular remodeling. Firstly, we found that JOSD2 was up-regulated in aortic smooth muscle cells but not endothelial cells of Ang II-challenged mouse vascular tissues. Whole-body knockout of JOSD2 significantly deteriorated Ang II-induced vascular remodeling in mice. Conversely, Ang II-induced vascular remodeling was reversed by VSMC-specific JOSD2 overexpression. In vitro, JOSD2 deficiency aggravated the fibrosis, proliferation, and migration induced by Ang II in vascular smooth muscle cells (VSMCs), while these changes were reversed by JOSD2 overexpression. RNA-seq analysis showed that the protective effects of JOSD2 in VSMCs were related to TGFβ-SMAD pathway. Furthermore, the LC-MS/MS analysis identified SMAD7, a negative regulator in TGFβ-SMAD pathway, as the substrate of JOSD2. JOSD2 specifically bound to the MH1 domain of SMAD7 to removed K48-linked Ub chains of SMAD7 at lysine 220 to sustain SMAD7 stability. Taken together, our finding reveals that JOSD2-SMAD7 axis is critical for relieving Ang II-induced vascular remodeling and JOSD2 maybe a novel and potential therapeutic target for hypertensive vascular remodeling.
Project description:Vascular development involves complex changes in gene expression necessary to dictate the behaviour of differentiating endothelial cells within the emerging vascular network. However, the transcriptional programs regulating vascular development are poorly understood. Here we use a microarray approach to profile the genes regulated in response to SOX7 overexpression.