Abstract P097: Molecular Mechanisms of VEGFR Inhibition-induced Endothelial Cell Damage

VEGF/VEGFR inhibitors, used as anti-angiogenic drugs to treat cancer, induce severe hypertension. Molecular mechanisms whereby VEGF inhibitors cause hypertension are unclear, but nitric oxide (NO) and oxidative stress may be involved. We questioned whether reactive oxygen species (ROS) and Ang II, important regulators of vascular function in hypertension, also play a role in VEGF inhibitor-induced vascular dysfunction. Human microvascular endothelial cells (HMECs) were stimulated with vatalanib (VAT-VEGFR inhibitor) and gefitinib (GEF-EGFR inhibitor) in the absence/presence of Ang II. Activation of eNOS and MAPKs were assessed by immunoblotting. Antioxidant enzyme mRNA was analysed by qPCR. Microparticle levels were measured by flow cytometry. Endothelial microparticles, biomarkers of endothelial damage, tend to increase in subjects treated with VEGFR inhibitors. Phosphorylation of eNOS activation site (Ser1177) (28.3% ± 7.1) was decreased by VAT, while no changes were observed after exposure of HMECs to GEF (p<0.05). VAT decreased mRNA expression of Nox4 (0.5 ± 0.2) and H2O2-regulating antioxidants enzymes such as catalase (0.4 ± 0.1) and glutathione peroxidase (0.4 ± 0.1), while increased mRNA levels of Nox5 (3.35±1.1) (p<0.05 vs. veh). Ang II stimulation increased eNOS (171.2% ± 17.4) and ERK1/2 (177.5% ± 38.5) activation (p<0.05); all effects were blocked only by GEF. Inhibition of VEGFR also blocked Ang II effects on SOD1 (1.33 ± 0.1), HO-1 (1.6 ± 0.3) and NQO1 (1.6 ± 0.3) mRNA levels (p<0.05). In addition, Ang II increased Nox4 mRNA expression through VEGFR-dependent mechanisms. VEGFR1/2 and AT2R, but not AT1R, were expressed in HMEC. Ang II effects on eNOS phosphorylation were inhibited by PD123319 (AT2R antagonist) but not by losartan (AT1R antagonist). In conclusion, our data identify novel mechanisms whereby AngII, possibly through AT2R-dependent VEGFR transactivation, regulates eNOS activation, MAPK signalling and H2O2-related antioxidant enzymes. In addition to changes in NO availability, VEGFR inhibition may interfere with the redox status of endothelial cells, leading to vascular dysfunction and hypertension.

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Abstract 261: Endothelial Cells Contribute to RAS Activation in Microvascular Smooth Muscle Cells

Circulation Research ◽

10.1161/res.111.suppl_1.a261 ◽

2012 ◽

Vol 111 (suppl_1) ◽

Author(s):

Kayoko Miyata ◽

Ryousuke Satou ◽

L Gabriel Navar

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Mrna Expression ◽

Culture Medium ◽

Primary Cultures ◽

Mrna Levels ◽

Ang Ii ◽

Relative Ratio ◽

Renin Mrna ◽

Afferent Arterioles

Introduction: We have demonstrated that Ang II augments angiotensinogen (AGT) expression in rat preglomerular vascular smooth muscle cells (VSMCs). However, it is unclear if endothelial cells (ECs) are involved in augmentation of AGT in renal afferent arterioles. Hypothesis: We assessed the hypothesis that the ECs respond to paracrine signals that Ang II contribute to AGT augmentation in VSMCs. Objective: We established primary cultures of preglomerular ECs and examined the effects of Ang II and/or culture medium from ECs on AGT expression in preglomerular VSMCs. Methods and Results: We established primary cultures of preglomerular ECs, isolated from afferent arterioles of Sprague-Dawley rats. The cells were identified as ECs by being positive for a marker, CD34 and endothelial NOS and negative for alpha-SMA (a marker for VSMCs) and P4H-b (a marker for Fibroblasts) by immnostaining. The expression levels of AGT mRNA and renin mRNA in preglomerular ECs were examined by real-time RT-PCR. Ang II (100 pmol/L) increased AGT mRNA levels (1.34 +/- 0.16, by 100 pmol/L, N=4) and Renin mRNA levels (6.16 +/- 0.96, by 100 nmol/L, N=4) in ECs. On the other hand, the same dose of Ang II suppressed Renin mRNA expression in isolated Juxtaglomerular cells (JGs). These results indicate that preglomerular ECs are respond to Ang II and exclude the possible contamination of JGs into ECs. 100 pmol/L of Ang II increased AGT mRNA expression levels (1.37 +/- 0.03, relative ratio, N=4) in preglomerular VSMCs and the culture medium of ECs without Ang II treatment also more increased AGT mRNA expression (1.62 +/- 0.13, relative ratio, N=4) in preglomerular VSMCs. The AGT mRNA expression augmentation was enhanced when preglomerular VSMCs were treated with culture medium of Ang II-treated preglomerular ECs (2.39 +/- 0.41, relative ratio, N=4). The synergistic effects of Ang II and preglomerular ECs were also observed in PAI-1 expression in preglomerular VSMCs. Conclusion: These data demonstrate that preglomerular ECs contribute to Ang II-upregulation of AGT in renal afferent arterioles leading to further Ang II augmentation, which leads to increases in inflammatory and sclerotic factors in preglomerular VSMCs.

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Abstract 067: Downregulation Of Vascular Factor-erythroid 2-related Factor-2 And Associated Antioxidant Enzymes In Hypertension

Hypertension ◽

10.1161/hyp.64.suppl_1.067 ◽

2014 ◽

Vol 64 (suppl_1) ◽

Author(s):

Rheure A Lopes ◽

Karla B Neves ◽

Augusto Montezano ◽

Rita Tostes ◽

Rhian Touyz

Keyword(s):

Oxidative Stress ◽

Antioxidant Enzymes ◽

Mrna Expression ◽

Vascular Dysfunction ◽

Ros Generation ◽

Related Factor ◽

Mrna Levels ◽

Ang Ii ◽

Peroxiredoxin 1 ◽

Anti Oxidant

Oxidative stress plays an important role in vascular dysfunction in hypertension. While mechanisms regulating vascular pro-oxidants are emerging, there is a paucity of information on anti-oxidant systems. Factor-erythroid 2-related factor-2 (Nrf2) is a master regulator of antioxidants and its role in hypertension remains elusive. We assessed vascular Nrf2 in hypertension by studying mesenteric vessels and VSMCs from WKY and SHRSP rats. Cells were stimulated with Ang II (10-7M) in the absence/presence of Nrf2 activators (bardoxolone or L-sulforaphane). ROS generation was assessed by chemiluminescence and amplex red. mRNA expression of anti-oxidant enzymes was assessed by qPCR. Nrf2 activity was analyzed by ELISA. Nrf2 activity was decreased in arteries (18%) and VSMCs (48%) in SHRSP (p<0.05 vs WKY). mRNA levels of antioxidant enzymes were reduced in SHRSP (SOD 1 (64%), catalase (60%), peroxiredoxin 1 (75%) and glutathione peroxidase (54%) Ang II increased Nrf2 activity in VSMCs from WKY (197%, 4h) and SHRSP (44%, 4h) (p<0.05, vs. vehicle). This was associated with increased antioxidant mRNA expression in WKY rats (SOD1-32%, catalase-42%, thioredoxin-71%, peroxiredoxin 1-90%, quinone oxidoreductase-84%; p<0.05 vs. vehicle) but not in SHRSP. ROS production and glucose-6-phosphate dehydrogenase (source of NADPH) mRNA levels were increased in SHRSP. Ang II-induced ROS generation in VSMCs from WKY and SHRSP was blocked by Nrf2 activators. Vascular function assessment, by wire myography, demonstrated that increased contractility (Emax Phe: WKY 113.4±5,67 vs. SHRSP 159.0±8.29) and decreased endothelial-dependent relaxation (Emax ACh: WKY 88.7±3.13 vs. SHRSP 74.7±3.25, p<0.05) in SHRSP were corrected by bardoxolone and L-sulforaphane. In conclusion, vascular dysfunction in SHRSP is associated with oxidative stress, decreased Nrf2 activity and reduced Nrf2-regulated antioxidant enzymes. A similar molecular phenotype was observed in Ang II-stimulated VSMCs. Nrf-2 agonists ameliorated vascular dysfunction in SHRSP. Our findings suggest that Nrf-2 downregulation may contribute to redox-sensitive vascular dysfunction and could be a therapeutic target in hypertension. Financial Support: ScWB.

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Ubiquinol Supplementation Improves Gender-Dependent Cerebral Vasoreactivity and Ameliorates Chronic Inflammation and Endothelial Dysfunction in Patients with Mild Cognitive Impairment

Antioxidants ◽

10.3390/antiox10020143 ◽

2021 ◽

Vol 10 (2) ◽

pp. 143

Author(s):

Sonia García-Carpintero ◽

Javier Domínguez-Bértalo ◽

Cristina Pedrero-Prieto ◽

Javier Frontiñán-Rubio ◽

Mariano Amo-Salas ◽

...

Keyword(s):

Endothelial Cells ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Vascular Dysfunction ◽

Transcranial Doppler Sonography ◽

Endothelial Damage ◽

Microvascular Endothelial Cell ◽

Neurological Improvement ◽

Male Patients ◽

Cerebral Vasoreactivity

Ubiquinol can protect endothelial cells from multiple mechanisms that cause endothelial damage and vascular dysfunction, thus contributing to dementia. A total of 69 participants diagnosed with mild cognitive impairment (MCI) received either 200 mg/day ubiquinol (Ub) or placebo for 1 year. Cognitive assessment of patients was performed at baseline and after 1 year of follow-up. Patients’ cerebral vasoreactivity was examined using transcranial Doppler sonography, and levels of Ub and lipopolysaccharide (LPS) in plasma samples were quantified. Cell viability and necrotic cell death were determined using the microvascular endothelial cell line bEnd3. Coenzyme Q10 (CoQ) levels increased in patients supplemented for 1 year with ubiquinol versus baseline and the placebo group, although higher levels were observed in male patients. The higher cCoQ concentration in male patients improved cerebral vasoreactivity CRV and reduced inflammation, although the effect of Ub supplementation on neurological improvement was negligible in this study. Furthermore, plasma from Ub-supplemented patients improved the viability of endothelial cells, although only in T2DM and hypertensive patients. This suggests that ubiquinol supplementation could be recommended to reach a concentration of 5 μg/mL in plasma in MCI patients as a complement to conventional treatment.

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Expression of human endothelin-converting enzyme isoforms: role of angiotensin IIThis article is one of a selection of papers published in the special issue (part 1 of 2) on Forefronts in Endothelin.

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y08-023 ◽

2008 ◽

Vol 86 (6) ◽

pp. 299-309 ◽

Cited By ~ 1

Author(s):

W. Goettsch ◽

A. Schubert ◽

H. Morawietz

Keyword(s):

Endothelial Cells ◽

Mrna Expression ◽

Umbilical Vein ◽

Artery Bypass ◽

Control Group ◽

Ang Ii ◽

Converting Enzyme ◽

Mammary Arteries ◽

Endothelin Converting Enzyme ◽

Internal Mammary

A key step in endothelin-1 (ET-1) synthesis is the proteolytic cleavage of big ET-1 by the endothelin-converting enzyme-1 (ECE-1). Four alternatively spliced isoforms, ECE-1a to ECE-1d, have been discovered; however, regulation of the expression of specific ECE-1 isoforms is not well understood. Therefore, we stimulated primary human umbilical vein endothelial cells (HUVECs) with angiotensin II (Ang II). Furthermore, expression of ECE-1 isoforms was determined in internal mammary arteries of patients undergoing coronary artery bypass grafting surgery. Patients had received one of 4 therapies: angiotensin-converting enzyme inhibitors (ACE-I), Ang II type 1 receptor blockers (ARB), HMG-CoA reductase inhibitors (statins), and a control group that had received neither ACE-I, ARB (that is, treatment not interfering in the renin–angiotensin system), nor statins. Under control conditions, ECE-1a is the dominant isoform in HUVECs (4.5 ± 2.8 amol/μg RNA), followed by ECE-1c (2.7 ± 1.0 amol/μg), ECE-1d (0.49 ± 0.17 amol/μg), and ECE-1b (0.17 ± 0.04 amol/μg). Stimulation with Ang II did not change the ECE-1 expression pattern or the ET-1 release. We found that ECE-1 mRNA expression was higher in patients treated with statins than in patients treated with ARB therapy (5.8 ± 0.76 RU versus 3.0 ± 0.4 RU), mainly attributed to ECE-1a. In addition, ECE-1a mRNA expression was higher in patients receiving ACE-I therapy than in patients receiving ARB therapy (1.68 ± 0.27 RU versus 0.83 ± 0.07 RU). We conclude that ECE-1a is the major ECE-1 isoform in primary human endothelial cells. Its expression in internal mammary arteries can be regulated by statin therapy and differs between patients with ACE-I and ARB therapy.

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Abstract 315: Efficacy and Safety of Rivaroxaban in in vitro Experiments With the Endothelial Cells

Circulation Research ◽

10.1161/res.119.suppl_1.315 ◽

2016 ◽

Vol 119 (suppl_1) ◽

Author(s):

Kaname Seki ◽

Yosuke Mizuno ◽

Toku Sakashita ◽

Jun Tanno ◽

Shintaro Nakano ◽

...

Keyword(s):

Endothelial Cells ◽

Time Course ◽

Umbilical Vein ◽

Endothelial Damage ◽

Coagulation Cascade ◽

Elisa Assay ◽

Mrna Levels ◽

Factor X ◽

Clotting Factors ◽

Inflammatory Phase

Aim: Activated factor X (FXa) plays important roles in the thrombin generation and in inflammation, which is evoked during the endothelial damage. Although rivaroxaban is a selective FXa antagonist, it is one of the key therapies in ischemic heart disease, and yet its function in the state of inactivated coagulation cascade is uncertain. Rivaroxaban blocks FXa in the blood but not the tissue, while factor X is converted to FXa only when glutamic acid is changed to γ-carboxyglutamic acid by vitamin K following the intrinsic clotting factors and/or cellular injury activation. To uncover this aspect, we performed the following experiments. Methods and results: Human umbilical vein endothelial cells (HUVECs) were obtained from Lonza Co., Ltd. The cells were grown to 80% confluence and were treated with rivaroxaban (100nM, 500nM, 1000nM, 2000nM respectively) without FXa stimulation for 4 h, 10 h or 24 h. Cells and medium were collected and then their RNA was extracted from the cells. The qPCR of MCP-1, PAR1-4 and the DNA micro arrays (The GeneChip Human Gene 2.0 ST Array, Affymetrix) were performed. There was neither increased nor decreased gene expression significantly in either experimental time course of the qPCRs or the the DNA micro arrays. The ELISA assay of MCP-1 with medium showed non-activated MCP-1. As a next step, cells were treated with 100nM FXa and with/without rivaroxaban in same time course, and cells and medium were collected for further experiments. FXa evoked induction of mRNA levels for several pro-inflammatory cytokines including MCP-1 maximally at 4h, whereas MCP-1 was maximally evoked at 24 h in ELISA assay. Interestingly rivaroxaban inhibited both in all time course, at 4 hour inflammatory phase and at 24 hour inflammatory phase. Conclusion: Collectively, these results suggest that rivaroxaban may be safe in the inactivated coagulation state, and has the efficacy to attenuate the endothelial damage evoked by FXa and by pro-inflammatory cytokine genes.

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Vascular Dysfunction in Preeclampsia

Cells ◽

10.3390/cells10113055 ◽

2021 ◽

Vol 10 (11) ◽

pp. 3055

Author(s):

Megan A. Opichka ◽

Matthew W. Rappelt ◽

David D. Gutterman ◽

Justin L. Grobe ◽

Jennifer J. McIntosh

Keyword(s):

Oxidative Stress ◽

Molecular Mechanisms ◽

Vascular Dysfunction ◽

Treatment Options ◽

Cardiovascular Disorder ◽

Endothelial Damage ◽

Spiral Artery ◽

Mitochondrial Stress ◽

Inflammatory State ◽

Life Threatening

Preeclampsia is a life-threatening pregnancy-associated cardiovascular disorder characterized by hypertension and proteinuria at 20 weeks of gestation. Though its exact underlying cause is not precisely defined and likely heterogenous, a plethora of research indicates that in some women with preeclampsia, both maternal and placental vascular dysfunction plays a role in the pathogenesis and can persist into the postpartum period. Potential abnormalities include impaired placentation, incomplete spiral artery remodeling, and endothelial damage, which are further propagated by immune factors, mitochondrial stress, and an imbalance of pro- and antiangiogenic substances. While the field has progressed, current gaps in knowledge include detailed initial molecular mechanisms and effective treatment options. Newfound evidence indicates that vasopressin is an early mediator and biomarker of the disorder, and promising future therapeutic avenues include mitigating mitochondrial dysfunction, excess oxidative stress, and the resulting inflammatory state. In this review, we provide a detailed overview of vascular defects present during preeclampsia and connect well-established notions to newer discoveries at the molecular, cellular, and whole-organism levels.

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Activation of Bone Marrow-Derived Cells Angiotensin (Ang) II Type 1 Receptor by Ang II Promotes Atherosclerotic Plaque Vulnerability

International Journal of Molecular Sciences ◽

10.3390/ijms19092621 ◽

2018 ◽

Vol 19 (9) ◽

pp. 2621

Author(s):

Maxime Pellegrin ◽

Karima Bouzourène ◽

Jean-François Aubert ◽

Aimable Nahimana ◽

Michel Duchosal ◽

...

Keyword(s):

Bone Marrow ◽

Mrna Expression ◽

Atherosclerotic Plaque ◽

Cholesterol Metabolism ◽

Mrna Levels ◽

Ang Ii ◽

Plaque Vulnerability ◽

Plaque Development ◽

Pro Inflammatory Cytokines

Angiotensin (Ang) II triggers vulnerable atherosclerotic plaque development. Bone marrow (BM)-derived cells are key players in atherogenesis but whether Ang II induces plaque vulnerability directly through Ang II type 1 receptor (AT1R) activation on these cells remains to be clarified. In the present study, we investigated whether a lack of AT1R on BM-derived cells might affect Ang II-mediated vulnerable plaque development. The 2-kidney, 1-clip (2K1C) model (Ang II-dependent mouse model of advanced atherosclerosis and vulnerable plaques) was generated in ApoE−/− mice transplanted with AT1aR−/− or AT1aR+/+ BM. Plasma cholesterol as well as hepatic mRNA expression levels of genes involved in cholesterol metabolism were significantly lower in 2K1C mice transplanted with AT1aR−/− BM than in controls. Atherosclerotic lesions were significantly smaller in AT1aR−/− BM 2K1C mice (−79% in the aortic sinus and −71% in whole aorta compared to controls). Plaques from AT1aR−/− BM 2K1C mice exhibited reduced lipid core/fibrous cap and macrophage/smooth muscle cells ratios (−82% and −88%, respectively), and increased collagen content (+70%), indicating a more stable phenotype. Moreover, aortic mRNA levels of pro-inflammatory cytokines IL-12p35, IL-1β, and TNF-α were significantly reduced in AT1aR−/− BM 2K1C mice. No significant differences in either the number of circulating Ly6Chigh inflammatory monocytes and Ly6Clow resident anti-inflammatory monocyte subsets, or in mRNA levels of aortic M1 or M2 macrophage markers were observed between the two groups. No significant differences were observed in splenic mRNA levels of T cell subsets (Th1, Th2, Th17 and Treg) markers between the two groups. In conclusion, direct AT1R activation by Ang II on BM-derived cells promotes hepatic mRNA expression of cholesterol-metabolism-related genes and vascular mRNA expression of pro-inflammatory cytokines that may lead to plaque instability.

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Abstract P006: Liraglutide Attenuates Cardiac Fibrosis and Vascular Dysfunction in a Non-diabetic Angiotensin II-infusion Model via Anti-inflammatory and Anti-oxidant Mechanisms

Hypertension ◽

10.1161/hyp.66.suppl_1.p006 ◽

2015 ◽

Vol 66 (suppl_1) ◽

Author(s):

Huey Wen Lee ◽

Melita Brdar ◽

Robert Widdop ◽

Anthony Dear ◽

Tracey Gaspari

Keyword(s):

Blood Pressure ◽

Vascular Function ◽

Cardiac Fibrosis ◽

Vascular Dysfunction ◽

Cardiomyocyte Hypertrophy ◽

High Dose ◽

Protective Effects ◽

Ang Ii ◽

Treatment Protocols ◽

Glucose Levels

Glucagon-like peptide-1 (GLP-1) based therapies are used to treat type II diabetes via increasing insulin secretion and inhibiting glucagon production. Recent evidence suggests that activating the GLP-1 receptor may also mediate direct vaso-protective effects. Therefore the objective of the study was to determine whether GLP-1R stimulation conferred cardio- and vaso-protection in a non-diabetic setting using the angiotensin (Ang) II infusion model of hypertension and cardiovascular dysfunction. Male C57Bl/6J mice (4-6 months) were assigned to one of the following 4 week treatment protocols: 1) vehicle (saline), 2) Ang II (800ng/kg/day), 3) Ang II + liraglutide (30μg/kg/day), 4) Ang II + liraglutide (300μg/kg/day). All treatments were administered via osmotic mini-pumps (s.c). After 4 weeks the effect of liraglutide treatment on blood pressure, vascular function and cardiac remodelling was examined. Liraglutide (both doses) attenuated Ang II-induced increase in systolic blood pressure (Ang II: 175.3 ± 8.6mmHg vs Ang II+Lirag (30) 150.2 ± 6.4 mmHg or Ang II+Lirag (300): 145.4 ± 6.9 mmHg) without affecting blood glucose levels. Liraglutide (both doses) completely prevented Ang II-induced endothelial dysfunction (% maximum relaxation: Ang II=50.7 ± 7.8%; Ang II+Lirag (30)=82.7 ± 5.8; Ang II+Lirag (300)=81.5 ± 6.1%). In the heart, liraglutide prevented Ang II-induced cardiomyocyte hypertrophy (n=7-10; p<0.05) and reduced collagen deposition (% collagen expression: Ang II=4.4 ± 0.5 vs Ang II+Lirag(300)=2.9 ± 0.3; n=7-9; p<0.01). This anti-fibrotic effect was attributed to reduced fibroblast/myofibroblast expression as well as decreased inflammation with reduced NFκB and MCP-1 expression and decreased oxidative stress with a significant reduction in superoxide production using high dose of liraglutide. Overall, stimulation of GLP-1R in a non-diabetic setting protected against Ang II-mediated cardiac hypertrophy, cardiac fibrosis and vascular dysfunction, indicating potential for use of GLP-1 based therapies in treatment of cardiovascular disease independent of diabetes.

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Abstract 14820: Sirt7 Deficiency in Blood Vessel Components Impairs Vascular Function by Inhibiting Cell Cycle- and Inflammatory-Related Protein Expression

Circulation ◽

10.1161/circ.132.suppl_3.14820 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Yuichi Kimura ◽

Yasuhiro Izumiya ◽

Satoshi Araki ◽

Satoru Yamamura ◽

Yoshiro Onoue ◽

...

Keyword(s):

Cell Proliferation ◽

Endothelial Cells ◽

Blood Flow ◽

Vascular Function ◽

Vascular Dysfunction ◽

Vascular Diseases ◽

Tube Formation ◽

Hindlimb Ischemia ◽

Proliferation Assay

Introduction: Aging is a well-established cardiovascular risk factor and associated with vascular dysfunction. Sirt7, one of the members of mammalian sirtuin family, is thought to be involved in age-related diseases. However, little is known about the relative contribution of Sirt7 in vascular dysfunction. Hypothesis: Sirt7 maintains vascular cell functions and its deficiency plays a critical role in vascular diseases. Methods: Sirt7 loss- and gain-of-function experiments were performed with human aortic smooth muscle cells (HAoSMCs) and human umbilical vein endothelial cells (HUVECs). In vivo, blood flow recovery was evaluated by hindlimb ischemia model in homozygous Sirt7 deficient (Sirt7-/-) and wild-type (WT) mice. Irradiated WT mice were intravenously received bone marrow (BM) cells from WT or Sirt7 -/- mouse to achieve BM transfer. Results: An RNAi-medicated Sirt7 knockdown resulted in a significant inhibition of HAoSMCs proliferation following serum or Platelet-derived growth factor BB (PDGF-BB) stimulation as determined by cell count, BrdU cell proliferation assay and MTS proliferation assay. Knockdown of endogenous Sirt7 also reduced cell migration as revealed by Boyden chamber migration assay. The Cyclin D1 and Cyclin dependent kinase 2 (CDK2) protein levels were significantly decreased in Sirt7 siRNA-treated HAoSMCs in response to serum or PDGF-BB stimulation. In endothelial cells, knockdown of Sirt7 attenuated tube formation, proliferation and migration. These changes were accompanied by reduced ERK activation and VCAM-1 mRNA and protein expression in Sirt7 siRNA-treated HUVECs. Conversely, overexpression of Sirt7 by adenovirus enhanced tube formation and cell proliferation. In vivo, blood flow recovery in response to hindlimb ischemia was significantly attenuated in Sirt7-/- mice compared with WT mice. There was no difference in blood flow recovery between WT mice transplanted with WT or Sirt7-/- BM cells suggesting that Sirt7 deficiency in vascular cells have a predominant effect on attenuated blood flow recovery in response to hindlimb ischemia. Conclusions: Sirt7 in blood vessel components have an important role in maintenance of vascular function. Sirt7 could be a promising therapeutic target for vascular diseases.

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Gangliosides Contribute to Vascular Insulin Resistance

International Journal of Molecular Sciences ◽

10.3390/ijms20081819 ◽

2019 ◽

Vol 20 (8) ◽

pp. 1819 ◽

Cited By ~ 5

Author(s):

Norihiko Sasaki ◽

Yoko Itakura ◽

Masashi Toyoda

Keyword(s):

Insulin Resistance ◽

Endothelial Cells ◽

Vascular Function ◽

Molecular Mechanisms ◽

The Elderly ◽

Necrosis Factor Alpha ◽

Aortic Endothelial Cells ◽

Inflammatory Conditions ◽

Factor Alpha

Insulin in physiological concentrations is important to maintain vascular function. Moreover, vascular insulin resistance contributes to vascular impairment. In the elderly, other factors including hypertension, dyslipidemia, and chronic inflammation amplify senescence of vascular endothelial and smooth muscle cells. In turn, senescence increases the risk for vascular-related diseases such as arteriosclerosis, diabetes, and Alzheimer’s disease. Recently, it was found that GM1 ganglioside, one of the glycolipids localized on the cell membrane, mediates vascular insulin resistance by promoting senescence and/or inflammatory stimulation. First, it was shown that increased GM1 levels associated with aging/senescence contribute to insulin resistance in human aortic endothelial cells (HAECs). Second, the expression levels of gangliosides were monitored in HAECs treated with different concentrations of tumor necrosis factor-alpha (TNFα) for different time intervals to mimic in vivo acute or chronic inflammatory conditions. Third, the levels of insulin signaling-related molecules were monitored in HAECs after TNFα treatment with or without inhibitors of ganglioside synthesis. In this review, we summarize the molecular mechanisms of insulin resistance in aged/senescent and TNFα-stimulated endothelial cells mediated by gangliosides and highlight the possible roles of gangliosides in vascular insulin resistance-related diseases.

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