Project description:The evolutionary conserved Taurine Upregulated Gene 1 (TUG1) is a ubiquitously expressed gene that is one of the highest expressed genes in human and rodent endothelial cells (ECs). We here show that TUG1 expression decreases significantly in aging mouse carotid artery ECs and human ECs in vitro, indicating a potential role in the aging endothelial vasculature system. We therefore investigated if, and how, TUG1 might function in aging ECs, but despite extensive phenotyping found no alterations in basal EC proliferation, apoptosis, barrier function, migration, mitochondrial function, or monocyte adhesion upon TUG1 silencing in vitro. TUG1 knockdown did slightly and significantly decrease cumulative sprout length upon vascular endothelial growth factor A stimulation in human umbilical vein endothelial cells (HUVECs), though TUG1-silenced HUVECs displayed no transcriptome-wide mRNA expression changes explaining this effect. Further, ectopic expression of the highly conserved and recently discovered 153 amino acid protein translated from certain TUG1 transcript isoforms did not alter angiogenic sprouting in vitro. Our data show that, despite a high expression and strong evolutionary conservation of both the TUG1 locus and the protein sequence it encodes, TUG1 does not seem to play a major role in basic endothelial cell function.
Project description:Age-related diseases pose great challenges to health care systems worldwide. During aging, endothelial senescence increases the risk for cardiovascular disease. Recently, it was described that Phosphatase 1 Nuclear Targeting Subunit (PNUTS) has a central role in cardiomyocyte aging and homeostasis. Here, we determined the role of PNUTS in endothelial cell aging. We confirmed that PNUTS is repressed in senescent endothelial cells (ECs). Moreover, PNUTS silencing elicits several of the hallmarks of endothelial aging: senescence, reduced angiogenesis and loss of barrier function. To validate our findings in vivo, we generated an endothelial-specific inducible PNUTS-deficient mouse line (Cdh5-CreERT2;PNUTSfl/fl), termed PNUTSEC-KO. Two weeks after PNUTS deletion, PNUTSEC-KO mice presented severe multiorgan failure and vascular leakage. Transcriptomic analysis of PNUTS-silenced HUVECs and lungs of PNUTSEC-KO mice revealed that the PNUTS-PP1 axis tightly regulates the expression of semaphorin 3B (SEMA3B). Indeed, silencing of SEMA3B completely restored barrier function after PNUTS loss-of-function. These results reveal a pivotal role for PNUTS in endothelial homeostasis through a SEMA3B downstream pathway that provides a potential target against the effects of aging in ECs.
Project description:Age-related diseases pose great challenges to health care systems worldwide. During aging, endothelial senescence increases the risk for cardiovascular disease. Recently, it was described that Phosphatase 1 Nuclear Targeting Subunit (PNUTS) has a central role in cardiomyocyte aging and homeostasis. Here, we determined the role of PNUTS in endothelial cell aging. We confirmed that PNUTS is repressed in senescent endothelial cells (ECs). Moreover, PNUTS silencing elicits several of the hallmarks of endothelial aging: senescence, reduced angiogenesis and loss of barrier function. To validate our findings in vivo, we generated an endothelial-specific inducible PNUTS-deficient mouse line (Cdh5-CreERT2;PNUTSfl/fl), termed PNUTSEC-KO. Two weeks after PNUTS deletion, PNUTSEC-KO mice presented severe multiorgan failure and vascular leakage. Transcriptomic analysis of PNUTS-silenced HUVECs and lungs of PNUTSEC-KO mice revealed that the PNUTS-PP1 axis tightly regulates the expression of semaphorin 3B (SEMA3B). Indeed, silencing of SEMA3B completely restored barrier function after PNUTS loss-of-function. These results reveal a pivotal role for PNUTS in endothelial homeostasis through a SEMA3B downstream pathway that provides a potential target against the effects of aging in ECs.
Project description:Glioblastomas show heterogeneous histological features. These distinct phenotypic states are thought to be originated by the glioma stem cells (GSCs), which are highly tumorigenic and self-renewing sub-population of tumor cells that have different functional characteristics. We found TUG1, a large non-coding RNA (lncRNA) is highly expressed in GSCs. TUG1 was reported to interact with PRC2 via its exon 2 and represses its target gene expression in trans. In order to identify the genetic loci enriched with TUG1 in GSC, we performed modified RNA pull-down assay coupled with promoter-microarray analysis using BrU-labeled TUG1.
Project description:We have sequenced mouse embryonic fibroblasts (MEFs) and 6 organs (testes, prostate, liver, heart, spleen, and eye) harvested from adult male wild type and Tug1 knockout (Tug1_tm1.1Vlcg) mice in a C57BL/6J/129S6 (N3-C57BL/6J, no Neo) background. Additional sequencing was done on the testes of a Tug1 rescue mouse, which contains a doxycycline inducible allele for Tug1 (tg(Tug1)) and CAGs-rtTA3 in the Tug1 knockout background (Tug1_tmn1.1Vlcg).
Project description:We generated a genome wide map of instances where the long noncoding RNA, Tug1, binds to DNA in cultured mouse podocytes under normal glucose conditions using Chromatin-RNA Precipitation coupled with high throughput sequencing (ChIRP-Seq) 48 alternating (even, odd) biotynilated probes were designed to span the full length of Tug1 RNA. Chromatin was prepared from gluteraldehyde crosslinked nuclei from early passage podocytes. Chromatin extracts were duplicated with either even or odd probes. Duplicate samples for Input DNA, Even pulldown (PD) and Odd PD DNA was purified following incubation and supplied for Illumina sequencing by ArrayStar (Rockville, MD).
Project description:Cardiomyocyte Ca2+ is buffered by mitochondria via the mitochondrial calcium uniporter (MCU) complex. The MCU complex consists of pore-forming proteins including the mitochondrial calcium uniporter (MCU), and regulatory proteins such as mitochondrial calcium uptake proteins 1 and 2 (MICU1/2). The stoichiometry of these proteins influences the sensitivity to Ca2+ and activity of the complex. However, the factors that regulate their gene expression remain incompletely understood. Long non-coding RNAs (lncRNAs) regulate gene expression through various mechanisms, and we recently found that the lncRNA Tug1 affected the expression of MCU-associated genes. To further explore this, we knocked down Tug1 (Tug1 KD) in H9c2 rat cardiomyocytes using antisense LNA oligo. This led to increased MCU protein expression yet this did not enhance a marker of mitochondrial Ca2+ uptake. RNA-seq revealed that Tug1 KD increased Mcu and led to differential expression of genes and pathways related to Ca2+ regulation in the heart. To understand the effect of this on Ca2+ signalling, we measured phosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and its downstream target cAMP Response Element-Binding protein (CREB), a transcription factor known to promote Mcu gene expression. Tug1 KD attenuated the increase in CAMKII and CREB phosphorylation in response to ionomycin, a Ca2+ ionophore. Inhibition of CaMKII, but not CREB, partially prevented the Tug1 KD mediated increase in Mcu. Together, these data suggest that Tug1 modulates MCU expression via a mechanism that may involve CAMKII and CREB. The Tug1 mediated regulation of MCU on mitochondrial Ca2+ uptake, may have functional consequences for cellular Ca2+ handling which could have implications for cardiac disease.
Project description:Mitochondrial adaptations play a central role in the beneficial effects of exercise, particularly in metabolically active tissues such as skeletal muscle. Despite this, the molecular regulators of mitochondrial adaptive responses have not yet been fully elucidated. The long non-coding RNA (lncRNA) taurine-upregulated gene 1 (TUG1) interacts with the master transcriptional regulator of mitochondrial biogenesis, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). In skeletal muscle of young healthy humans (n=14), we observed that TUG1 gene expression was elevated following an acute bout of continuous, moderate intensity cycling exercise and this positively correlated with PPARGC1A gene expression. Therefore, we hypothesised that TUG1 may modulate skeletal muscle mitochondrial responses to exercise. Knockdown (KD) of Tug1 in differentiating mouse myotubes resulted in altered mitochondrial morphology and impaired mitochondrial respiratory function, which was accompanied by greater myosin heavy chain slow isoform protein expression, despite lower Ppargc1a gene and MFN2 protein expression. Tug1 KD prevented the induction of Ppargc1a expression from a Ca2+ mediated stimulus (caffeine) yet the response to an AMPK agonist (AICAR ) was unaffected. RNA-sequencing revealed that Tug1 KD affected genes relating to mitochondrial Ca2+ transport and downstream targets of PGC-1α. Finally, in response to electrical pulse stimulation (EPS), an in vitro model of exercise in myotubes, there were ~300 genes whose upregulation in response to EPS was either blunted or augmented by Tug1 KD, including regulators of muscle differentiation and myogenesis. These data demonstrate that the lncRNA Tug1 is a novel regulator of skeletal muscle transcriptional responses to exercise and myogenesis.