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Project description:Hypoxia provokes adaptive responses of cells, which ensure their energy supply including the adjustment of the transcriptome to match their metabolism. In this context, we explored the transcriptional impact of nuclear factor of activated T-cells 5 (NFAT5) on the function of vascular smooth muscle cells (VSMC) in the hypoxic lung. Exposure to hypoxia induced a rapid nuclear translocation of NFAT5 in cultured murine VSMCs. SMC-specific ablation of Nfat5 (Nfat5(SMC-/-)) increases the systolic pressure in the right ventricle (RVSP) of the mouse heart and impairs its function upon exposure to hypoxia for 7 and 21 days. Analyses of the transcriptome of the lung revealed a robust increase in the expression genes attributed to mitochondrial respiration. Further analyses of hypoxia-exposed pulmonary artery VSMCs revealed that loss of Nfat5 stimulates the expression of multiple mitochondria-related genes encoding cytochrome oxidases while decreasing the expression of lactate dehydrogenase A (Ldha) and phosphofructokinase 3 (Pfkfb3). Both, inhibition of LDHA or PFKFB3 activity and loss of Nfat5 stimulated the mitochondrial production of reactive oxygen species (ROS) in hypoxic pulmonary artery VSMCs while scavenging of ROS normalized the RVSP values in hypoxia-exposed Nfat5(SMC-/-) mice. In summary, our findings suggest a crucial role for NFAT5 in adjusting the transcriptome of hypoxia-exposed pulmonary artery VSMCs to support an adequate glycolysis-centered metabolism. Loss of Nfat5 impairs this response thereby fueling the mitochondrial respiration and ROS production that amplifies the hypoxia-mediated constriction of pulmonary arteries.
2021-11-26 | GSE178463 | GEO
Project description:Hypoxia provokes adaptive responses of cells, which ensure their energy supply including the adjustment of the transcriptome to match their metabolism. In this context, we explored the transcriptional impact of nuclear factor of activated T-cells 5 (NFAT5) on the function of vascular smooth muscle cells (VSMC) in the hypoxic lung. Exposure to hypoxia induced a rapid nuclear translocation of NFAT5 in cultured murine VSMCs. SMC-specific ablation of Nfat5 (Nfat5(SMC-/-)) increases the systolic pressure in the right ventricle (RVSP) of the mouse heart and impairs its function upon exposure to hypoxia for 7 and 21 days. Analyses of the transcriptome of the lung revealed a robust increase in the expression genes attributed to mitochondrial respiration. Further analyses of hypoxia-exposed pulmonary artery VSMCs revealed that loss of Nfat5 stimulates the expression of multiple mitochondria-related genes encoding cytochrome oxidases while decreasing the expression of lactate dehydrogenase A (Ldha) and phosphofructokinase 3 (Pfkfb3). Both, inhibition of LDHA or PFKFB3 activity and loss of Nfat5 stimulated the mitochondrial production of reactive oxygen species (ROS) in hypoxic pulmonary artery VSMCs while scavenging of ROS normalized the RVSP values in hypoxia-exposed Nfat5(SMC-/-) mice. In summary, our findings suggest a crucial role for NFAT5 in adjusting the transcriptome of hypoxia-exposed pulmonary artery VSMCs to support an adequate glycolysis-centered metabolism. Loss of Nfat5 impairs this response thereby fueling the mitochondrial respiration and ROS production that amplifies the hypoxia-mediated constriction of pulmonary arteries.
2021-11-26 | GSE178462 | GEO
Project description:NFAT5/TonEBP controls metabolic adaption and tone of pulmonary vascular smooth muscle cells in the hypoxic lung
| PRJNA739156 | ENA
Project description:NFAT5/TonEBP controls metabolic adaption and tone of pulmonary vascular smooth muscle cells in the hypoxic lung [SMC]
| PRJNA739164 | ENA
Project description:NFAT5/TonEBP controls metabolic adaption and tone of pulmonary vascular smooth muscle cells in the hypoxic lung [normoxia vs hypoxia]
| PRJNA739162 | ENA
Project description:Chronic hypoxia increases the resistance of pulmonary arteries by stimulating their contraction and augmenting their coverage by smooth muscle cells (SMCs). While these responses require adjustment of the vascular SMC transcriptome, regulatory elements are not well defined in this context. Here, we explored the functional role of the transcription factor nuclear factor of activated T-cells 5 (NFAT5/TonEBP) in the hypoxic lung. Regulatory functions of NFAT5 were investigated in cultured artery SMCs and lungs from control (Nfat5fl/fl) and SMC-specific Nfat5-deficient (Nfat5(SMC)-/-) mice. Exposure to hypoxia promoted the expression of genes associated with metabolism and mitochondrial oxidative phosphorylation (OXPHOS) in Nfat5(SMC)-/- versus Nfat5fl/fl lungs. In vitro, hypoxia-exposed Nfat5-deficient pulmonary artery SMCs elevated the level of OXPHOS-related transcripts, mitochondrial respiration, and production of reactive oxygen species (ROS). Right ventricular functions were impaired while pulmonary right ventricular systolic pressure (RVSP) was amplified in hypoxia-exposed Nfat5(SMC)-/- versus Nfat5fl/fl mice. Scavenging of mitochondrial ROS normalized the raise in RVSP. Our findings suggest a critical role for NFAT5 as a suppressor of OXPHOS-associated gene expression, mitochondrial respiration, and ROS production in pulmonary artery SMCs that is vital to limit ROS-dependent arterial resistance in a hypoxic environment.
| S-EPMC8699676 | biostudies-literature
Project description:Cytoskeletal reorganization and migration are critical responses which enable vascular smooth muscle cells (VSMCs) cells to evade, compensate, or adapt to alterations in biomechanical stress. An increase in wall stress or biomechanical stretch as it is elicited by arterial hypertension promotes their reorganization in the vessel wall which may lead to arterial stiffening and contractile dysfunction. This adaptive remodeling process is dependent on and driven by subtle phenotype changes including those controlling the cytoskeletal architecture and motility of VSMCs. Recently, it has been reported that the transcription factor nuclear factor of activated T-cells 5 (TonEBP/NFAT5) controls critical aspects of the VSMC phenotype and is activated by biomechanical stretch. We therefore hypothesized that NFAT5 controls the expression of gene products orchestrating cytoskeletal reorganization in stretch-stimulated VSMCs. Automated immunofluorescence and Western blot analyses revealed that biomechanical stretch enhances the expression and nuclear translocation of NFAT5 in VSMCs. Subsequent in silico analyses suggested that this transcription factor binds to the promotor region of ACTBL2 encoding kappa-actin which was shown to be abundantly expressed in VSMCs upon exposure to biomechanical stretch. Furthermore, ACTBL2 expression was inhibited in these cells upon siRNA-mediated knockdown of NFAT5. Kappa-actin appeared to be aligned with stress fibers under static culture conditions, dispersed in lamellipodia and supported VSMC migration as its knockdown diminishes lateral migration of these cells. In summary, our findings delineated biomechanical stretch as a determinant of NFAT5 expression and nuclear translocation controlling the expression of the cytoskeletal protein ACTBL2. This response may orchestrate the migratory activity of VSMCs and thus promote maladaptive rearrangement of the arterial vessel wall during hypertension.
| S-EPMC4253659 | biostudies-literature
Project description:BackgroundNuclear factor of activated T-cells 5 (NFAT5) has recently been described to control the phenotype of vascular smooth muscle cells (VSMCs). Although an increase in wall stress or stretch (eg, elicited by hypertension) is a prototypic determinant of VSMC activation, the impact of this biomechanical force on the activity of NFAT5 is unknown. This study intended to reveal the function of NFAT5 and to explore potential signal transduction pathways leading to its activation in stretch-stimulated VSMCs.Methods and resultsHuman arterial VSMCs were exposed to biomechanical stretch and subjected to immunofluorescence and protein-biochemical analyses. Stretch promoted the translocation of NFAT5 to the nucleus within 24 hours. While the protein abundance of NFAT5 was regulated through activation of c-Jun N-terminal kinase under these conditions, its translocation required prior activation of palmitoyltransferases. DNA microarray and ChiP analyses identified the matrix molecule tenascin-C as a prominent transcriptional target of NFAT5 under these conditions that stimulates migration of VSMCs. Analyses of isolated mouse femoral arteries exposed to hypertensive perfusion conditions verified that NFAT5 translocation to the nucleus is followed by an increase in tenascin-C abundance in the vessel wall.ConclusionsCollectively, our data suggest that biomechanical stretch is sufficient to activate NFAT5 both in native and cultured VSMCs where it regulates the expression of tenascin-C. This may contribute to an improved migratory activity of VSMCs and thus promote maladaptive vascular remodeling processes such as hypertension-induced arterial stiffening.
| S-EPMC4187483 | biostudies-literature
Project description:Vascular cells are continuously exposed to mechanical stress that may wreak havoc if exceeding physiological levels. Consequently, mechanisms facing such a challenge are indispensable and contribute to the adaptation of the cellular phenotype. To this end, vascular smooth muscle cells (VSMCs) activate mechanoresponsive transcription factors promoting their proliferation and migration to initiate remodeling the arterial wall. In mechanostimulated VSMCs, we identified nuclear factor of activated T-cells 5 (NFAT5) as transcriptional regulator protein and intended to unravel mechanisms controlling its expression and nuclear translocation. In cultured human VSMCs, blocking RNA synthesis diminished both baseline and stretch-induced NFAT5 mRNA expression while inhibition of the proteasome promoted accumulation of the NFAT5 protein. Detailed PCR analyses indicated a decrease in expression of NFAT5 isoform A and an increase in isoform C in mechanoactivated VSMCs. Upon overexpression, only NFAT5c was capable to enter the nucleus in control- and stretch-stimulated VSMCs. As evidenced by analyses of NFAT5c mutants, nuclear translocation required palmitoylation, phosphorylation at Y143 and was inhibited by phosphorylation at S1197. On the functional level, overexpression of NFAT5c forces its accumulation in the nucleus as well as transcriptional activity and stimulated VSMC proliferation and migration. These findings suggest that NFAT5 is continuously expressed and degraded in resting VSMCs while expression and accumulation of isoform C in the nucleus is facilitated during biomechanical stress to promote an activated VSMC phenotype.
| S-EPMC6115610 | biostudies-literature
Project description:The metal binding protein metallothionein (MT) is a target for nitric oxide (NO), causing release of bound zinc that affects myogenic reflex in systemic resistance vessels. Here, we investigate a role for NO-induced zinc release in pulmonary vasoregulation. We show that acute hypoxia causes reversible constriction of intraacinar arteries (<50 microm/L) in isolated perfused mouse lung (IPL). We further demonstrate that isolated pulmonary (but not aortic) endothelial cells constrict in hypoxia. Hypoxia also causes NO-dependent increases in labile zinc in mouse lung endothelial cells and endothelium of IPL. The latter observation is dependent on MT because it is not apparent in IPL of MT(-/-) mice. Data from NO-sensitive fluorescence resonance energy transfer-based reporters support hypoxia-induced NO production in pulmonary endothelium. Furthermore, hypoxic constriction is blunted in IPL of MT(-/-) mice and in wild-type mice, or rats, treated with the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)-ethylenediamine (TPEN), suggesting a role for chelatable zinc in modulating HPV. Finally, the NO donor DETAnonoate causes further vasoconstriction in hypoxic IPL in which NO vasodilatory pathways are inhibited. Collectively, these data suggest that zinc thiolate signaling is a component of the effects of acute hypoxia-mediated NO biosynthesis and that this pathway may contribute to constriction in the pulmonary vasculature.
| S-EPMC2735130 | biostudies-literature