Abstract P346: Endothelial Function and NO Bioavailability are Improved in Angiotensin Ii-treated Transglutaminase-2 Knock-out Mice

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Carmine Savoia ◽  
Emanuele Arrabito ◽  
Sergio Chiandotto ◽  
Carmine Nicoletti ◽  
Raffaella Carletti ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Transglutaminase 2 ◽  
Mesenteric Arteries ◽  
Ros Production ◽  
Resistance Arteries ◽  
Response Curves ◽  
Knock Out ◽  
Positive Modulator ◽  
No Bioavailability ◽  
Knock Out Mice

We hypothesized that transglutaminase-2 (TG2) may contribute to the impaired functional properties of resistance arteries from angiotensin-II-treated mice. TG2-knockout mice (TG2-K/O, 12 weeks old, n=6) and wild type (WT) mice were treated or not with angiotensin-II (400ng/kg/min) for 14 days. Blood pressure (BP) and heart rate (HR) were measured by tail-cuff method. Endothelium-dependent and -independent relaxations were assessed by concentration-response curves to acetylcholine (1nM-to-100μM)±L-NAME (100μM) and sodium nitroprusside (10nM-to-1mM) respectively, in mesenteric arteries pre-contracted with norepinephrine (10μM). The expression of p-eNOS-(S1177)/eNOS, NOSIP (the negative modulator of eNOS), NOX-1, and its positive modulator ERp72 were evaluated in aorta by immunoblotting. Reactive oxygen species (ROS) production in aorta was evaluated by dihydroethidium staining. Plasma nitrate/nitrate were measured by ELISA. BP and HR were higher in TG2-K/O mice compared to WT (116.8±0.9 mmHg vs 89.6±1.5 mmHg, P<0.001; and 595.0±15.0 bpm vs 467.1±14.7 bpm, P<0.001, respectively). In both groups, angiotensin-II increased significantly BP (+28% in WT, and +21% in TG2-K/O) and HR (+33% in WT, and +9% in TG2-K/O). Acetylcholine-induced relaxation was preserved in WT and TG2-K/O and it was significantly impaired by angiotensin-II only in WT (-28%). L-NAME blunted this response in all the groups, although this effect was less evident in angiotensin-II-treated WT. Endothelium-independent relaxation was similar in all the groups. Plasma nitrates/nitrates and p-eNOS-(S1177)/eNOS were similar in WT and TG2-K/O, and they were reduced by angiotensin-II significantly only in WT (-37% and -44%, respectively). NOSIP expression was similar in both WT and TG2-K/O and was significantly increased by angiotensin-II only in WT (+40%). ROS production was similar in WT and TG2-K/O and significantly increased by angiotensin-II only in WT (+9%). NOX-1 and ERp72 were similar in WT and TG2-K/O and were significantly increased by angiotensin-II only in WT (+23% and +29%, respectively). In conclusion TG2 may contribute to endothelial dysfunction through the modulation of ROS production and the reduction of NO bioavailability in angiotensin-II infused mice.

Abstract 189: Toll-like Receptor 2 Blockade Decreases Contractility in Angiotensin II-induced Hypertensive Rat Resistance Arteries

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Trevor Hardigan ◽  
Maria-Alicia Sepulveda ◽  
Kenia Pedrosa Nunes ◽  
R. Clinton Webb
Keyword(s):  
Angiotensin Ii ◽  
Vascular Dysfunction ◽  
Renin Angiotensin System ◽  
Mesenteric Arteries ◽  
Sodium Balance ◽  
Sprague Dawley ◽  
Resistance Arteries ◽  
Response Curves ◽  
Tlr2 Expression ◽  
The Impact

Toll-like receptors (TLRs) are pattern recognition receptors of the innate immune system that recognize endogenous damage-associated molecular patterns (DAMPS). TLR2 plays a role in cardiovascular diseases such as atherosclerosis and heart failure, but its role in hypertension is unknown. Angiotensin II (ANG), the effector molecule of the renin-angiotensin system, has been shown to cause an immune response leading to an inflammatory profile, in addition to its effects on vascular tone and sodium balance. We hypothesized that signaling through TLR2 in ANG-induced hypertension contributes to an increase in resistance artery contractility and vascular dysfunction. Sprague-Dawley rats were implanted with osmotic mini-pumps dispensing ANG (60 mg/day) for a 28 day period. Systolic blood pressure (measured directly via femoral canulation to confirm the ANG rats as a model of hypertension) was significantly increased in the ANG-treated rats (170 ±4.79 mmHg) vs. control (97 ±6.9 mmHg (p<0.05)). Concentration response curves to norepinephrine (NE; 10-9-10-4 M) were performed in second and third order mesenteric arteries from control and angiotensin-treated rats. Vessels were pre-incubated with and without antibody to TLR2 (1μg) for 35 minutes prior to the concentration-response curves to determine the impact of TLR2 blockade. The EMax (force of contraction as % of maximum KCl response) of the ANG vessels treated with anti-TLR2 was significantly lower than that of the ANG vessels alone (EMax: 129.2±10.69% vs 183.8±16.73%, respectively), and comparable to control-vessel levels (EMax in control vessels: 135.1±4.360%, p<0.05). Additionally, we sought to determine protein levels of TLR2 and downstream signaling protein MyD88 in the mesenteric arteries. In the arteries from the ANG treated animals, TLR2 expression was significantly increased 2.95±0.20 fold above control, and MyD88 expression was increased 1.35±0.06 fold above control (p<0.05). This suggests that TLR2 signaling leads to augmented contractility and is associated with the vascular dysfunction observed in hypertension.

scholarly journals Pregnancy Enhances the Angiotensin (Ang)-(1–7) Vasodilator Response in Mesenteric Arteries and Increases the Renal Concentration and Urinary Excretion of Ang-(1–7)

Endocrinology ◽  
2003 ◽  
Vol 144 (8) ◽  
pp. 3338-3343 ◽  
Author(s):  
Liomar A. A. Neves ◽  
Aleck F. Williams ◽  
David B. Averill ◽  
Carlos M. Ferrario ◽  
Michael P. Walkup ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Excretion Rate ◽  
Virgin Female ◽  
Cardiovascular Regulation ◽  
Mesenteric Arteries ◽  
Female Rats ◽  
Resistance Arteries ◽  
Urinary Excretion Rate ◽  
Response Curves ◽  
Mesenteric Vessels

Abstract The vasoactive effect of angiotensin (Ang)-(1–7) in mesenteric resistance arteries together with its plasma and kidney concentration and urinary excretion was assessed in pregnant and virgin rats. Mesenteric arteries (230–290 μm) were mounted in a pressurized myograph system and Ang-(1–7) concentration-dependent response curves (10−10–10−5m) were determined in arteries preconstricted with endothelin-1 (10−7m). The Ang-(1–7) response was investigated in vessels with and without pretreatment with the Ang-(1–7) antagonist [d-[Ala7]-Ang-(1–7)] (10−7m). Ang-(1–7) caused a significantly enhanced, concentration-dependent dilation of mesenteric vessels (EC50 = 2.7 nm) from pregnant compared with virgin female rats. d-[Ala7]-Ang-(1–7) eliminated the vasodilator effect of Ang-(1–7). There was no significant change in plasma concentration of Ang-(1–7) in pregnant animals. On the other hand, 24 h urinary excretion and kidney concentration of Ang-(1–7) were significantly higher in pregnant animals. The increased mesenteric dilation to Ang-(1–7) with enhanced kidney concentration and 24 h urinary excretion rate of Ang-(1–7) suggests an important role for this peptide in cardiovascular regulation during pregnancy.

scholarly journals NADPH Oxidase 2 Mediates Myocardial Oxygen Wasting in Obesity

Antioxidants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 171 ◽  
Author(s):  
Anne D. Hafstad ◽  
Synne S. Hansen ◽  
Jim Lund ◽  
Celio X. C. Santos ◽  
Neoma T. Boardman ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Mitochondrial Function ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Mechanical Efficiency ◽  
Ros Production ◽  
Knock Out ◽  
Obesity And Diabetes ◽  
Mitochondrial Ros ◽  
Nadph Oxidase 2 ◽  
Knock Out Mice

Obesity and diabetes are independent risk factors for cardiovascular diseases, and they are associated with the development of a specific cardiomyopathy with elevated myocardial oxygen consumption (MVO2) and impaired cardiac efficiency. Although the pathophysiology of this cardiomyopathy is multifactorial and complex, reactive oxygen species (ROS) may play an important role. One of the major ROS-generating enzymes in the cardiomyocytes is nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2), and many potential systemic activators of NOX2 are elevated in obesity and diabetes. We hypothesized that NOX2 activity would influence cardiac energetics and/or the progression of ventricular dysfunction following obesity. Myocardial ROS content and mechanoenergetics were measured in the hearts from diet-induced-obese wild type (DIOWT) and global NOK2 knock-out mice (DIOKO) and in diet-induced obese C57BL/6J mice given normal water (DIO) or water supplemented with the NOX2-inhibitor apocynin (DIOAPO). Mitochondrial function and ROS production were also assessed in DIO and DIOAPO mice. This study demonstrated that ablation and pharmacological inhibition of NOX2 both improved mechanical efficiency and reduced MVO2 for non-mechanical cardiac work. Mitochondrial ROS production was also reduced following NOX2 inhibition, while cardiac mitochondrial function was not markedly altered by apocynin-treatment. Therefore, these results indicate a link between obesity-induced myocardial oxygen wasting, NOX2 activation, and mitochondrial ROS.

scholarly journals Retinol Saturase Knock-Out Mice are Characterized by Impaired Clearance of Apoptotic Cells and Develop Mild Autoimmunity

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 737 ◽  
Author(s):  
Zsolt Sarang ◽  
Tibor Sághy ◽  
Zsófia Budai ◽  
László Ujlaky-Nagy ◽  
Judit Bedekovics ◽  
...  
Keyword(s):  
Transglutaminase 2 ◽  
Tissue Homeostasis ◽  
Apoptotic Cells ◽  
Wild Type ◽  
Integrin Receptors ◽  
Macrophage Differentiation ◽  
Phagocytic Capacity ◽  
Knock Out ◽  
Knock Out Mice ◽  
Number Of Cells

Apoptosis and the proper clearance of apoptotic cells play a central role in maintaining tissue homeostasis. Previous work in our laboratory has shown that when a high number of cells enters apoptosis in a tissue, the macrophages that engulf them produce retinoids to enhance their own phagocytic capacity by upregulating several phagocytic genes. Our data indicated that these retinoids might be dihydroretinoids, which are products of the retinol saturase (RetSat) pathway. In the present study, the efferocytosis of RetSat-null mice was investigated. We show that among the retinoid-sensitive phagocytic genes, only transglutaminase 2 responded in macrophages and in differentiating monocytes to dihydroretinol. Administration of dihydroretinol did not affect the expression of the tested genes differently between differentiating wild type and RetSat-null monocytes, despite the fact that the expression of RetSat was induced. However, in the absence of RetSat, the expression of numerous differentiation-related genes was altered. Among these, impaired production of MFG-E8, a protein that bridges apoptotic cells to the αvβ3/β5 integrin receptors of macrophages, resulted in impaired efferocytosis, very likely causing the development of mild autoimmunity in aged female mice. Our data indicate that RetSat affects monocyte/macrophage differentiation independently of its capability to produce dihydroretinol at this stage.

scholarly journals Attrition of Hepatic Damage Inflicted by Angiotensin II with α-Tocopherol and β-Carotene in Experimental Apolipoprotein E Knock-out Mice

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Kaliappan Gopal ◽  
Munusamy Gowtham ◽  
Singh Sachin ◽  
Mani Ravishankar Ram ◽  
Esaki M. Shankar ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Apolipoprotein E ◽  
Hepatic Damage ◽  
Knock Out ◽  
Knock Out Mice ◽  
Β Carotene

scholarly journals Transglutaminase 2 Inhibitor LDN 27219 Age-Dependently Lowers Blood Pressure and Improves Endothelium-Dependent Vasodilation in Resistance Arteries

Hypertension ◽  
2021 ◽  
Vol 77 (1) ◽  
pp. 216-227 ◽  
Author(s):  
Estéfano Pinilla ◽  
Simon Comerma-Steffensen ◽  
Judit Prat-Duran ◽  
Luis Rivera ◽  
Vladimir V. Matchkov ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Potassium Channels ◽  
Vascular Function ◽  
Transglutaminase 2 ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Closed Conformation ◽  
Open Conformation ◽  
Age Related

Transglutaminase 2 (TG2) is an enzyme which in the open conformation exerts transamidase activity, leading to protein cross-linking and fibrosis. In the closed conformation, TG2 participates in transmembrane signaling as a G protein. The unspecific transglutaminase inhibitor cystamine causes vasorelaxation in rat resistance arteries. However, the role of TG2 conformation in vascular function is unknown. We investigated the vascular effects of selective TG2 inhibitors by myography in isolated rat mesenteric and human subcutaneous resistance arteries, patch-clamp studies on vascular smooth muscle cells, and blood pressure measurements in rats and mice. LDN 27219 promoted the closed TG2 conformation and inhibited transamidase activity in mesenteric arteries. In contrast to TG2 inhibitors promoting the open conformation (Z-DON, VA5), LDN 27219 concentration-dependently relaxed rat and resistance human arteries by a mechanism dependent on nitric oxide, large-conductance calcium-activated and voltage-gated potassium channels 7, lowering blood pressure. LDN 27219 also potentiated acetylcholine-induced relaxation by opening potassium channels in the smooth muscle; these effects were abolished by membrane-permeable TG2 inhibitors promoting the open conformation. In isolated arteries from 35- to 40-week-old rats, transamidase activity was increased, and LDN 27219 improved acetylcholine-induced relaxation more than in younger rats. Infusion of LDN 27219 decreased blood pressure more effectively in 35- to 40-week than 12- to 14-week-old anesthetized rats. In summary, pharmacological modulation of TG2 to the closed conformation age-dependently lowers blood pressure and, by opening potassium channels, potentiates endothelium-dependent vasorelaxation. Our findings suggest that promoting the closed conformation of TG2 is a potential strategy to treat age-related vascular dysfunction and lowers blood pressure.

Cholesterol-Induced Suppression of Endothelial Kir Channels Is a Driver of Impairment of Arteriolar Flow-Induced Vasodilation in Humans

Hypertension ◽  
2021 ◽  
Author(s):  
Sang Joon Ahn ◽  
Ibra S. Fancher ◽  
Sara T. Granados ◽  
Natalia F. Do Couto ◽  
Chueh-Lung Hwang ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Ldl Cholesterol ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Significant Negative Correlation ◽  
Dominant Negative ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Knock Out ◽  
Major Mechanism

Dyslipidemia-induced endothelial dysfunction is an important factor in the progression of cardiovascular disease; however, the underlying mechanisms are unclear. Our recent studies demonstrated that flow-induced vasodilation (FIV) is regulated by inwardly rectifying K + channels (Kir2.1) in resistance arteries. Furthermore, we showed that hypercholesterolemia inhibits Kir2.1-dependent vasodilation. In this study, we introduced 2 new mouse models: (1) endothelial-specific deletion of Kir2.1 to demonstrate the role of endothelial Kir2.1 in FIV and (2) cholesterol-insensitive Kir2.1 mutant to determine the Kir2.1 regulation in FIV under hypercholesterolemia. FIV was significantly reduced in endothelial-specific Kir2.1 knock-out mouse mesenteric arteries compared with control groups. In cholesterol-insensitive Kir2.1 mutant mice, Kir2.1 currents were not affected by cyclodextrin and FIV was restored in cells and arteries, respectively, with a hypercholesterolemic background. To extend our observations to humans, 16 healthy subjects were recruited with LDL (low-density lipoprotein)-cholesterol ranging from 51 to 153 mg/dL and FIV was assessed in resistance arteries isolated from gluteal adipose. Resistance arteries from participants with >100 mg/dL LDL (high-LDL) exhibited reduced FIV as compared with those participants with <100 mg/dL LDL (low-LDL). A significant negative correlation was observed between LDL cholesterol and FIV in high-LDL. Expressing dominant-negative Kir2.1 in endothelium blunted FIV in arteries from low-LDL but had no further effect on FIV in arteries from high-LDL. The Kir2.1-dependent vasodilation more negatively correlated to LDL cholesterol in high-LDL. Overexpressing wild-type Kir2.1 in endothelium fully recovered FIV in arteries from participants with high-LDL. Our data suggest that cholesterol-induced suppression of Kir2.1 is a major mechanism underlying endothelial dysfunction in hypercholesterolemia.

Abstract P277: β-arrestin-2-mediated Vasodilatation In Mouse Mesenteric Arteries

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Victor M Pulgar ◽  
Krisztian Toth
Keyword(s):  
Vascular Function ◽  
Isometric Force ◽  
Mesenteric Arteries ◽  
Maximal Response ◽  
Lower Sensitivity ◽  
Dependent Manner ◽  
Resistance Arteries ◽  
Response Curves ◽  
Vascular Dilatation

As part of GPCRs-dependent signaling, β -arrestin-2 has been shown to stimulate eNOS activity and thus has the potential to modulate vascular function. We hypothesized that the absence of β -arrestin-2 would alter vascular dilatation and contraction in resistance arteries. We tested acetylcholine (ACh)-dependent relaxation and phenylephrine (PE)-dependent contraction in mouse mesenteric arteries isolated from 3-mo old male C57Bl6 (WT, n=5) and β -arrestin-2 KO ( βarr2 -/- , n=5) mice. Segments were mounted in a Wire Myograph (DMT) for determination of isometric force; vessels studied included intact, without endothelium, or pre-incubated with L-NAME (10 -4 M). Dose-response curves were performed for ACh (10 -10 -10 -4.5 M) and PE (10 -10 -10 -4.5 M). Data were acquired using a PowerLab (ADInstruments) system. Maximal response to ACh (ACh MAX ) was expressed as maximal relaxation after pre-constriction, maximal response to PE (PE MAX ) as % of contraction to 75mM KCl (%K MAX ), and sensitivity as pD 2 (-Log[EC 50 ]). Data were analyzed using Prism (GraphPad). After pre-constriction (PE, 3x10 -6 M), arteries from βarr2 -/- mice presented similar ACh MAX (79±6 vs. 82±6, p>0.05) and lower sensitivity to ACh compared to WT (6.66±0.2 vs. 7.12±0.1, p<0.05). The sensitivity of the contraction to PE was increased in βarr2 -/- arteries (6.4±0.2 vs. 6.04±0.1, p<0.05), with no changes in PE MAX . Differences in vasodilation and contraction were abolished in arteries without endothelium and in arteries pre-incubated with L-NAME. We conclude that the absence of β -arrestin-2 induces a pro-contractile phenotype in an endothelium- and nitric oxide-dependent manner in mouse resistance arteries.

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