Genetic ablation of TonEBP/NFAT5 in smooth muscle cells inhibits arterial remodeling
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ABSTRACT: Chronic biomechanical stress elicits remodeling of the arterial wall and causes detrimental arterial stenosis and stiffening. In this context, molecular determinants controlling proliferation and stress responses of vascular smooth muscle cells (VSMCs) have been insufficiently studied. We identified the transcription factor ‘nuclear factor of activated T-cells 5’ (NFAT5) as crucial regulatory element of mechanical stress responses of VSMCs. The relevance of this observation for biomechanically induced arterial remodeling was investigated in mice upon SMC-specific knockdown of NFAT5. While blood pressure levels, vascular architecture and flow-induced collateral growth were not affected in these mice, both hypertension-mediated arterial thickening and muscularization of pulmonary arteries during pulmonary artery hypertension (PAH) were impaired. In all models, a decrease in VSMC proliferation was observed indicating that NFAT5 controls activation of VSMCs in the remodeling arterial wall. Mechanistically, mechanoactivation of VSMCs promotes nuclear translocation NFTA5c upon its phosphorylation at Y143 and dephosphorylation at S1197. As evidenced by transcriptome studies, loss of NFAT5 in mechanoactivated VSMCs impairs expression of gene products controlling cell cycle and transcription/translation. These findings identify NFAT5 as molecular determinant of VSMC responses to biomechanical stress and arterial thickening.
Project description:Vascular smooth muscle cells (VSMCs) are a major cell type of the arterial wall and their functionality is associated with blood pressure regulation. Although royal jelly (RJ) has reported effects on anti-hypertension, the mechanism of blood pressure regulation by major royal jelly protein 1 (MRJP1), the most abundant RJ protein, is still unknown. Therefore, mrjp1 gene was delivered into mouse VSMCs to investigate how MRJP1 influences the VSMC functionality by functional and proteomic analysis.The data here are the proteomic analysis of triplicated control and MRJP1 expressing VSMCs.
Project description:Pro-inflammatory response of VSMCs is triggered by endothelial damage and a causative step for thrombosis and neointimal thickening in the arterial vessels. Therefore, we investigate a role of cytosolic Hsp60 as a novel pro-inflammatory mediator in VSMCs. Hsp60 was detected in the cytosol of VSMCs. The selective depletion of cytosolic Hsp60 in VSMCs reduced the IKK activation, repressed the induction of NF-κB-dependent pro-survival genes (MnSOD and Bfl-1/A1), and enhanced apoptotic death in response to TNF-α. Moreover, a quantitative RNA sequencing revealed that the expression of 75 genes among the 774 TNF-α-inducible genes was significantly reduced by the depletion of cytosolic Hsp60. In particular, the expression of pro-inflammatory cytokines/chemokines, such as CCL2, CCL20, and IL-6, was regulated by the cytosolic Hsp60 in VSMCs. Finally, the depletion of cytosolic Hsp60 markedly inhibited the neointimal thickening in the balloon-injured arterial vessels by inducing apoptotic cell death and inhibiting chemokine production. This study provides the first evidence that cytosolic Hsp60 could be a therapeutic target for preventing inflammation-driven VSMC hyperplasia in the injured vessels. Hsp60 normal vs knockout with TNF-alpha treatment
Project description:The activation of vascular smooth muscle cells (VSMCs) during hypertension-induced arterial remodeling processes relies on a change of the gene expression program, i.e., up-regulation of genes to induce migration, proliferation and matrix degradation/synthesis. At the same time, genes controlling the quiescent, contractile VSMC phenotype are down-regulated. We used microarrays to detail the global program of gene expression underlying hypertension-induced vascular remodeling in the presence and absence of regulator of G-protein signaling 5 (RGS5) and identified distinct classes of down-regulated genes during vascular remodeling when RGS5 was not present.
Project description:Cerebral aneurysms (CA) are a type of vascular disease that causes significant morbidity and mortality with rupture. Dysfunction of the vascular smooth muscle cells (VSMCs) from circle of Willis (CoW) vessels mediates CA formation as they are the major cell type of the arterial wall and play a role in maintaining vessel integrity. Dimethyl fumarate (DMF), a first-line oral treatment for relapsing-remitting multiple sclerosis, has been shown to inhibit VSMC proliferation and reduce CA formation in a mouse model. Potential unwanted side effects of DMF on VSMC function have not been investigated yet. The present study characterizes the impact of DMF on VSMC using scRNA-seq in CoW vessels following CA induction and further explores its role in mitochondrial function using in vitro VSMC cultures. Two weeks of DMF treatment following CA induction impaired the transcription of the glutathione redox system and downregulated mitochondrial respiration genes in VSMCs. In vitro, DMF treatment increased lactate formation and enhanced the mitochondrial production of reactive oxygen species (ROS). These effects rendered VSMCs vul-nerable to oxidative stress and led to mitochondrial dysfunction and enhancement of apoptosis. Taken together, our data support the concept that the DMF-mediated antiproliferative effect on VSMCs is linked to disturbed antioxidative functions resulting in altered mitochondrial metabo-lism. This negative impact of DMF treatment on VSMCs may be linked to preexisting alterations of cerebrovascular function due to renal hypertension. Therefore, before severe adverse effects emerge, it would be clinically relevant to develop indices or biomarkers linked to this disturbed antioxidative function to monitor patients undergoing DMF treatment.
Project description:Pro-inflammatory response of VSMCs is triggered by endothelial damage and a causative step for thrombosis and neointimal thickening in the arterial vessels. Therefore, we investigate a role of cytosolic Hsp60 as a novel pro-inflammatory mediator in VSMCs. Hsp60 was detected in the cytosol of VSMCs. The selective depletion of cytosolic Hsp60 in VSMCs reduced the IKK activation, repressed the induction of NF-κB-dependent pro-survival genes (MnSOD and Bfl-1/A1), and enhanced apoptotic death in response to TNF-α. Moreover, a quantitative RNA sequencing revealed that the expression of 75 genes among the 774 TNF-α-inducible genes was significantly reduced by the depletion of cytosolic Hsp60. In particular, the expression of pro-inflammatory cytokines/chemokines, such as CCL2, CCL20, and IL-6, was regulated by the cytosolic Hsp60 in VSMCs. Finally, the depletion of cytosolic Hsp60 markedly inhibited the neointimal thickening in the balloon-injured arterial vessels by inducing apoptotic cell death and inhibiting chemokine production. This study provides the first evidence that cytosolic Hsp60 could be a therapeutic target for preventing inflammation-driven VSMC hyperplasia in the injured vessels.
Project description:Cardiovascular (CV) disease is a leading cause of morbidity and mortality in Western societies. Even after accounting for traditional CV risk factors (e.g. obesity, smoking and hypertension), the inflammation-driven thickening and stiffening of central arteries is a strong predictor of adverse outcomes. Arterial wall changes are universally associated with advancing age and show unparalleled worsening in metabolic syndrome. In mice, resveratrol ameliorates a high-fat diet induced arterial wall inflammation and slows age-associated physiologic deteriorations within the arterial wall. Here we tested resveratrol in adult male rhesus monkeys, an experimental model relevant to humans. A diet rich in fat and sucrose (HFS) led to an increase in body weight as well as thickening and stiffening of the aortic wall, marked by diffuse inflammation, fibrosis and fat infiltration. Dietary resveratrol supplementation prevented diet-induced structural and functional alterations within the aortic wall, and abrogated the deleterious vascular endothelial and smooth muscle responses. Integrative genomic and proteomic analyses of aortic tissues revealed molecular signatures consistent with improved vascular functions. Thus, resveratrol conferred protection against the initiation of diet-induced inflammatory events that progress to pathological thickening and stiffening of large arteries. Dietary resveratrol may therefore hold promise as a novel therapy to ameliorate metabolic stress-induced CV disease.
Project description:Cardiovascular (CV) disease is a leading cause of morbidity and mortality in Western societies. Even after accounting for traditional CV risk factors (e.g. obesity, smoking and hypertension), the inflammation-driven thickening and stiffening of central arteries is a strong predictor of adverse outcomes. Arterial wall changes are universally associated with advancing age and show unparalleled worsening in metabolic syndrome. In mice, resveratrol ameliorates a high-fat diet induced arterial wall inflammation and slows age-associated physiologic deteriorations within the arterial wall. Here we tested resveratrol in adult male rhesus monkeys, an experimental model relevant to humans. A diet rich in fat and sucrose (HFS) led to an increase in body weight as well as thickening and stiffening of the aortic wall, marked by diffuse inflammation, fibrosis and fat infiltration. Dietary resveratrol supplementation prevented diet-induced structural and functional alterations within the aortic wall, and abrogated the deleterious vascular endothelial and smooth muscle responses. Integrative genomic and proteomic analyses of aortic tissues revealed molecular signatures consistent with improved vascular functions. Thus, resveratrol conferred protection against the initiation of diet-induced inflammatory events that progress to pathological thickening and stiffening of large arteries. Dietary resveratrol may therefore hold promise as a novel therapy to ameliorate metabolic stress-induced CV disease. After baseline assessment, four male rhesus monkeys remained on the healthy standard diet (SD), 10 male rhesus monkeys were begun on a high fat/high sucrose (HFS) diet and 10 male rhesus monkeys were begun on a high fat/high sucrose (HFS) diet plus Resveratrol, 80mg/day. After one year of dietary intervention, the amount of resveratrol was increased to 240mg/day for one additional year. Tissues were then harvested for the array experiments.
Project description:The proliferation and remodeling of vascular smooth muscle cells (VSMCs) is an important pathological event in atherosclerosis and restenosis. Here we report that microRNA-132 (miR-132) blocks vascular smooth muscle cells (VSMC) proliferation by inhibiting the expression of LRRFIP1 [leucine-rich repeat (in Flightless 1) interacting protein-1]. MicroRNA microarray revealed that miR-132 was upregulated in the rat carotid artery after catheter injury, which was further confirmed by quantitative real-time RT-PCR. Transfection of an miR-132 mimic significantly inhibited the proliferation of VSMCs, whereas transfection of an miR-132 antagomir increased it. Bioinformatics showed that LRRFIP1 is a target candidate of miR-132. miR-132 down-regulated luciferase activity driven by a vector containing the 3’-untranslated region of Lrrfip1 in a sequence-specific manner. LRRFIP1 induced VSMC proliferation. Immunohistochemical analysis revealed that Lrrfip1 was clearly expressed along with the basal laminar area of smooth muscle, and its expression pattern was disrupted 7 days after arterial injury LRRFIP1 mRNA was decreased 14 days after injury. Delivery of miR-132 to rat carotid artery attenuated neointimal proliferation in carotid artery injury models. Our results suggest that miR-132 is a novel regulator of VSMC proliferation that represses neointimal formation by inhibiting LRRFIP1 expression. Balloon injury was induced in the carotid arteries of male Sprague–Dawley rats weighing approximately 250 g. Total RNA were extracted from the arterial sections after 10 days. MicroRNA profile of the sample was compared with non-injured control.
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.
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.