Endothelial Function in a Mouse Model of Myeloperoxidase Deficiency

Myeloperoxidase (MPO) activity is suggested to reduce the function of vascular nitric oxide, thereby contributing to endothelial dysfunction, although data in rodents are inconclusive. We examined vascular contractile and relaxant responses in MPO-deficient (MPO-/-) and wild-type mice to investigate the role for myeloperoxidase in the development of endothelial dysfunction. Carotid and saphenous arteries were taken from 8-month-old mice and studied in a myograph. Responses of carotid arteries to phenylephrine, high potassium, or acetylcholine (Ach) were statistically not different from controls. Treatment with lipopolysaccharide (LPS; to enhance endothelial dysfunction) reduced responses to Ach inMPO-/-but did not affect responses in wild-type. In response to high concentrations of Ach, carotid arteries responded with transient contractions, which were not different between the groups and not affected by LPS treatment. Saphenous arteries fromMPO-/-had smaller normalized diameters and developed less contractile force. Vessels fromMPO-/-were less sensitive to Ach than controls. These data suggest that mature MPO-deficient mice do not show enhanced endothelial function compared to wild-type mice, even when provoked with LPS treatment. The EDHF response appears to be reduced in MPO deficiency.

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IL-10 deficiency increases superoxide and endothelial dysfunction during inflammation

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2000.279.4.h1555 ◽

2000 ◽

Vol 279 (4) ◽

pp. H1555-H1562 ◽

Cited By ~ 79

Author(s):

Carol A. Gunnett ◽

Donald D. Heistad ◽

Daniel J. Berg ◽

Frank M. Faraci

Keyword(s):

Endothelial Function ◽

Xanthine Oxidase ◽

Carotid Arteries ◽

Interleukin 10 ◽

Vehicle Injection ◽

Endothelium Dependent Relaxation ◽

Deficient Mice ◽

Lps Treatment

Little is known about the role of interleukin-10 (IL-10), an anti-inflammatory cytokine, in blood vessels. We used IL-10-deficient mice (IL-10 −/−) to examine the hypothesis that IL-10 protects endothelial function after lipopolysaccharide (LPS) treatment. The responses of carotid arteries were studied in vitro 6 h after injection of a relatively low dose of LPS (10 μg ip). In IL-10 −/− mice, the maximum relaxation to ACh (3 μM) was 56 ± 6% (means ± SE) after LPS injection and 84 ± 4% after vehicle injection ( P < 0.05). Thus endothelium-dependent relaxation was impaired in carotid arteries from IL-10 −/− mice after LPS injection. In contrast, this dose of LPS did not alter relaxation to ACh in vessels from wild-type (IL-10 +/+) mice. Relaxation to nitroprusside and papaverine was similar in arteries from both IL-10 −/− and IL-10 +/+ mice after vehicle or LPS injection. Because inflammation is associated with increased levels of reactive oxygen species, we also tested the hypothesis that superoxide contributes to the impairment of endothelial function by LPS in the absence of IL-10. Results using confocal microscopy and hydroethidine indicated that levels of superoxide are elevated in carotid arteries from IL-10 −/− mice compared with IL-10 +/+ mice after LPS injection. The impaired relaxation of arteries from IL-10 −/− mice after LPS injection was restored to normal by polyethylene glycol-suspended superoxide dismutase (50 U/ml) or allopurinol (1 mM), an inhibitor of xanthine oxidase. These data provide direct evidence that IL-10 protects endothelial function after an acute inflammatory stimulus by limiting local increases in superoxide. The source of superoxide in this model may be xanthine oxidase.

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Protective effect of extracellular superoxide dismutase on endothelial function during aging

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.01342.2008 ◽

2009 ◽

Vol 296 (6) ◽

pp. H1920-H1925 ◽

Cited By ~ 39

Author(s):

Donald D. Lund ◽

Yi Chu ◽

Jordan D. Miller ◽

Donald D. Heistad

Keyword(s):

Superoxide Dismutase ◽

Endothelial Dysfunction ◽

Endothelial Function ◽

Ex Vivo ◽

Vascular Dysfunction ◽

Extracellular Superoxide Dismutase ◽

Mrna Levels ◽

Wild Type ◽

Vasomotor Function ◽

Old Mice

Endothelial vasomotor function decreases with increasing age. Extracellular superoxide dismutase (ecSOD) protects against vascular dysfunction in several disease states. The purpose of this study was to determine whether endogenous ecSOD protects against endothelial dysfunction in old mice. Vasomotor function of the aorta was studied ex vivo in wild-type (ecSOD+/+) and ecSOD-deficient (ecSOD−/−) mice at 11 (adult) and 29 (old) mo of age. Maximal relaxation to acetylcholine (10−4 M) was impaired in vessels from adult ecSOD−/− mice [75 ± 3% (mean ± SE)] compared with wild-type mice (89 ± 2%, P < 0.05). Maximal relaxation to acetylcholine (10−4 M) was profoundly impaired in aorta from old ecSOD−/− mice (45 ± 5%) compared with wild-type mice (75 ± 4%, P < 0.05). There was a significant correlation between expression of ecSOD and maximal relaxation to acetylcholine in adult and old mice. Tempol (1 mM), a scavenger of superoxide, improved relaxation in response to acetylcholine (63 ± 8%) in old ecSOD−/− mice ( P < 0.05), but not wild-type mice (75 ± 4%). Maximal relaxation to sodium nitroprusside was similar in aorta from adult and old wild-type and ecSOD−/− mice. Quantitative RT-PCR showed a decrease in mRNA levels of ecSOD and catalase in aorta of old mice and an increase in levels of TNFα and Nox-4 in aorta of old mice compared with adult mice. The findings support the hypothesis that impaired antioxidant mechanisms may contribute to cumulative increases in oxidative stress and impaired endothelial function in old mice. In conclusion, endogenous ecSOD plays an important role in protection against endothelial dysfunction during aging.

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Abstract 276: Systemic Delivery of Microrna-146a Improves Endothelial Function and Ameliorates Atherosclerosis in Apolipoprotein E-deficient Mice

Circulation Research ◽

10.1161/res.117.suppl_1.276 ◽

2015 ◽

Vol 117 (suppl_1) ◽

Author(s):

Shuangtao Ma ◽

Xiao Yu Tian ◽

Chaofeng Mu ◽

Haifa Shen ◽

Yunrong Zhang ◽

...

Keyword(s):

Endothelial Function ◽

Apolipoprotein E ◽

Carotid Arteries ◽

Treated Group ◽

Vehicle Group ◽

Early Event ◽

Aortic Tissue ◽

Systemic Delivery ◽

Plaque Area ◽

Deficient Mice

Rationale: Endothelial inflammation is an early event in the development of atherosclerosis. The microRNA (miR)-146a showed anti-inflammatory effects in cultured endothelial cells. In this study, we investigated the therapeutic role of miR-146a in endothelial function and atherosclerosis in apolipoprotein E (ApoE)-deficient mice. Methods and Results: The miR-146a was packaged into a multistage vector (MSV) that was conjugated with an E-selectin-targeting thioaptamer (ESTA) to form an ESTA-MSV microparticle. The ApoE-deficient mice were fed with Western diet and injected through tail vein with 15μg of miR-146a loaded ESTA-MSV microparticles or vehicle vectors biweekly for 12 weeks. The expressions of miR-146a in aortic tissue was increased by five times at two weeks after injection. However, the expressions of miR-146a in heart, lung, liver, spleen, kidney, and skeletal muscle were not increased. The acetylcholine-induced endothelium-dependent relaxations in both carotid arteries and aortas were significantly improved in mice from miR-146a treated group compared with vehicle group. In addition, the endothelium-dependent contractions of carotid arteries were also improved by miR-146a treatment. The en face oil red O staining of whole aortas showed the plaque area was decreased in miR-146a-treated mice. Application of miR-146a also decreased the plaque size, macrophages, and T-lymphocytes, but increased the collagen deposition and vascular smooth muscle cells in the sections of aortic roots. The PCR results showed that expressions of chemokine (C-C motif) ligand (CCL)-2, CCL-5, and CCL-8 were decreased by miR-146a. Conclusions: E-selectin-targeting delivery of miR-146a improves endothelial function and inhibits atherosclerosis.

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Vascular effects of LPS in mice deficient in expression of the gene for inducible nitric oxide synthase

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1998.275.2.h416 ◽

1998 ◽

Vol 275 (2) ◽

pp. H416-H421 ◽

Cited By ~ 23

Author(s):

Carol A. Gunnett ◽

Yi Chu ◽

Donald D. Heistad ◽

Angela Loihl ◽

Frank M. Faraci

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Carotid Arteries ◽

Inos Mrna ◽

Wild Type ◽

Vascular Effects ◽

Contractile Responses ◽

Vasomotor Function ◽

Oxide Synthase ◽

Deficient Mice

The inducible isoform of nitric oxide synthase (iNOS) is expressed after systemic administration of lipopolysaccharide (LPS). The importance of expression of iNOS in blood vessels is poorly defined. Because nitric oxide from iNOS may alter vasomotor function, we examined effects of LPS on vasomotor function in carotid arteries from iNOS-deficient mice. We studied contraction of the carotid artery from wild-type and iNOS-deficient mice in vitro 12 h after injection of LPS (20 mg/kg ip). Contractile responses to PGF2α (3–30 μM) and thromboxane A2 analog (U-46619; 3–100 nM) were evaluated using vascular rings from mice treated with vehicle or LPS. Maximum force of contraction generated by rings in response to PGF2α was 0.39 ± 0.02 and 0.25 ± 0.01 (SE) g ( n = 14) in vehicle and LPS-treated wild-type mice, respectively ( P < 0.001 vs. vehicle). Thus LPS reduced constrictor responses in wild-type mice. Thiocitrulline and aminoguanidine (inhibitors of iNOS) improved contractile responses from LPS-treated wild-type vessels. Indomethacin also improved constrictor responses in arteries from wild-type mice injected with LPS. In contrast, contraction of the carotid arteries in response to PGF2α and U-46619 was not impaired in LPS-treated iNOS-deficient mice, and contraction was not altered by inhibitors of iNOS. Expression of iNOS mRNA was confirmed using RT-PCR in carotid arteries from wild-type mice after injection of LPS but not vehicle. PCR products for iNOS were not observed in iNOS-deficient mice. These findings provide the first direct evidence that iNOS mediates impairment of vascular contraction after treatment with LPS.

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Red Blood Cell Peroxynitrite Causes Endothelial Dysfunction in Type 2 Diabetes Mellitus via Arginase

Cells ◽

10.3390/cells9071712 ◽

2020 ◽

Vol 9 (7) ◽

pp. 1712 ◽

Cited By ~ 4

Author(s):

Ali Mahdi ◽

John Tengbom ◽

Michael Alvarsson ◽

Bernhard Wernly ◽

Zhichao Zhou ◽

...

Keyword(s):

Diabetes Mellitus ◽

Type 2 Diabetes ◽

Type 2 Diabetes Mellitus ◽

Endothelial Dysfunction ◽

Endothelial Function ◽

Arginase Activity ◽

Oxygen Species ◽

Wild Type ◽

Arginase I

We recently showed that red blood cells (RBCs) from patients with type 2 diabetes mellitus (T2DM-RBCs) induce endothelial dysfunction through a mechanism involving arginase I and reactive oxygen species. Peroxynitrite is known to activate arginase in endothelial cells. Whether peroxynitrite regulates arginase activity in RBCs, and whether it is involved in the cross-talk between RBCs and the vasculature in T2DM, is unclear and elusive. The present study was designed to test the hypothesis that endothelial dysfunction induced by T2DM-RBCs is driven by peroxynitrite and upregulation of arginase. RBCs were isolated from patients with T2DM and healthy age matched controls. RBCs were co-incubated with aortae isolated from wild type rats for 18 h in the absence and presence of peroxynitrite scavenger FeTTPS. Evaluation of endothelial function in organ chambers by cumulative addition of acetylcholine as well as measurement of RBC and vessel arginase activity was performed. In another set of experiments, RBCs isolated from healthy subjects (Healthy RBCs) were incubated with the peroxynitrite donor SIN-1 with subsequent evaluation of endothelial function and arginase activity. T2DM-RBCs, but not Healthy RBCs, induced impairment in endothelial function, which was fully reversed by scavenging of RBC but not vascular peroxynitrite with FeTPPS. Arginase activity was up-regulated by the peroxynitrite donor SIN-1 in Healthy RBCs, an effect that was inhibited by FeTTPS. Healthy RBCs co-incubated with aortae in the presence of SIN-1 caused impairment of endothelial function, which was inhibited by FeTTPS or the arginase inhibitor ABH. T2DM-RBCs induced up-regulation of vascular arginase, an effect that was fully inhibited by FeTTPS. Collectively, our data indicate that RBCs impair endothelial function in T2DM via an effect that is driven by a peroxynitrite-mediated increase in arginase activity. This mechanism may be targeted in patients with T2DM for improvement in endothelial function.

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A KATP channel deficiency affects resting tension, not contractile force, during fatigue in skeletal muscle

AJP Cell Physiology ◽

10.1152/ajpcell.2000.279.5.c1351 ◽

2000 ◽

Vol 279 (5) ◽

pp. C1351-C1358 ◽

Cited By ~ 53

Author(s):

B. Gong ◽

T. Miki ◽

S. Seino ◽

J. M. Renaud

Keyword(s):

Soleus Muscle ◽

Force Frequency ◽

Wild Type ◽

Tetanic Force ◽

Major Function ◽

Resting Tension ◽

Force Recovery ◽

Fatigue Characteristics ◽

Old Mice ◽

Deficient Mice

The objective of this study was to determine how an ATP-sensitive K+ (KATP) channel deficiency affects the contractile and fatigue characteristics of extensor digitorum longus (EDL) and soleus muscle of 2- to 3-mo-old and 1-yr-old mice. KATP channel-deficient mice were obtained by disrupting the Kir6.2 gene that encodes for the protein forming the pore of the channel. At 2–3 mo of age, the force-frequency curve, the twitch, and the tetanic force of EDL and soleus muscle of KATPchannel-deficient mice were not significantly different from those in wild-type mice. However, the tetanic force and maximum rate of force development decreased with aging to a greater extent in EDL and soleus muscle of KATP channel-deficient mice (24–40%) than in muscle of wild-type mice (7–17%). During fatigue, the KATP channel deficiency had no effect on the decrease in tetanic force in EDL and soleus muscle, whereas it caused a significantly greater increase in resting tension when compared with muscle of wild-type mice. The recovery of tetanic force after fatigue was not affected by the deficiency in 2- to 3-mo-old mice, whereas in 1-yr-old mice, force recovery was significantly less in muscle of KATP channel-deficient than wild-type mice. It is suggested that the major function of the KATP channel during fatigue is to reduce the development of a resting tension and not to contribute to the decrease in force. It is also suggested that the KATP channel plays an important role in protecting muscle function in older mice.

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T1r3 taste receptor involvement in gustatory neural responses to ethanol and oral ethanol preference

Physiological Genomics ◽

10.1152/physiolgenomics.00113.2009 ◽

2010 ◽

Vol 41 (3) ◽

pp. 232-243 ◽

Cited By ~ 24

Author(s):

Susan M. Brasser ◽

Meghan B. Norman ◽

Christian H. Lemon

Keyword(s):

Taste Receptor ◽

Sweet Taste ◽

Receptor Protein ◽

Wild Type ◽

Ethanol Preference ◽

Background Strain ◽

Neurobiological Substrates ◽

High Concentrations ◽

Gustatory Neurons ◽

Deficient Mice

Elevated alcohol consumption is associated with enhanced preference for sweet substances across species and may be mediated by oral alcohol-induced activation of neurobiological substrates for sweet taste. Here, we directly examined the contribution of the T1r3 receptor protein, important for sweet taste detection in mammals, to ethanol intake and preference and the neural processing of ethanol taste by measuring behavioral and central neurophysiological responses to oral alcohol in T1r3 receptor-deficient mice and their C57BL/6J background strain. T1r3 knockout and wild-type mice were tested in behavioral preference assays for long-term voluntary intake of a broad concentration range of ethanol, sucrose, and quinine. For neurophysiological experiments, separate groups of mice of each genotype were anesthetized, and taste responses to ethanol and stimuli of different taste qualities were electrophysiologically recorded from gustatory neurons in the nucleus of the solitary tract. Mice lacking the T1r3 receptor were behaviorally indifferent to alcohol (i.e., ∼50% preference values) at concentrations typically preferred by wild-type mice (5–15%). Central neural taste responses to ethanol in T1r3-deficient mice were significantly lower compared with C57BL/6J controls, a strain for which oral ethanol stimulation produced a concentration-dependent activation of sweet-responsive NTS gustatory neurons. An attenuated difference in ethanol preference between knockouts and controls at concentrations >15% indicated that other sensory and/or postingestive effects of ethanol compete with sweet taste input at high concentrations. As expected, T1r3 knockouts exhibited strongly suppressed behavioral and neural taste responses to sweeteners but did not differ from wild-type mice in responses to prototypic salt, acid, or bitter stimuli. These data implicate the T1r3 receptor in the sensory detection and transduction of ethanol taste.

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Role of oxidative stress and AT1 receptors in cerebral vascular dysfunction with aging

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00300.2009 ◽

2009 ◽

Vol 296 (6) ◽

pp. H1914-H1919 ◽

Cited By ~ 67

Author(s):

Mary L. Modrick ◽

Sean P. Didion ◽

Curt D. Sigmund ◽

Frank M. Faraci

Keyword(s):

Oxidative Stress ◽

Endothelial Dysfunction ◽

Vascular Dysfunction ◽

Ang Ii ◽

Wild Type ◽

Very Old ◽

Vascular Responses ◽

Basilar Arteries ◽

Old Mice ◽

Cerebral Vascular

Vascular dysfunction occurs with aging. We hypothesized that oxidative stress and ANG II [acting via ANG II type 1 (AT1) receptors] promotes cerebral vascular dysfunction with aging. We studied young (5–6 mo), old (17–19 mo), and very old (23 ± 1 mo) mice. In basilar arteries in vitro, acetylcholine (an endothelium-dependent agonist) produced dilation in young wild-type mice that was reduced by ∼60 and 90% ( P < 0.05) in old and very old mice, respectively. Similar effects were seen using A23187, a second endothelium-dependent agonist. The vascular response to acetylcholine in very old mice was almost completely restored with tempol (a scavenger of superoxide) and partly restored by PJ34, an inhibitor of poly(ADP-ribose) polymerase (PARP). We used mice deficient in Mn-SOD (Mn-SOD+/−) to test whether this form of SOD protected during aging but found that age-induced endothelial dysfunction was not altered by Mn-SOD deficiency. Cerebral vascular responses were similar in young mice lacking AT1 receptors (AT1−/−) and wild-type mice. Vascular responses to acetylcholine and A23187 were reduced by ∼50% in old wild-type mice ( P < 0.05) but were normal in old AT1-deficient mice. Thus, aging produces marked endothelial dysfunction in the cerebral artery that is mediated by ROS, may involve the activation of PARP, but was not enhanced by Mn-SOD deficiency. Our findings suggest a novel and fundamental role for ANG II and AT1 receptors in age-induced vascular dysfunction.

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SARS-CoV-2 variants of concern infect the respiratory tract and induce inflammatory response in wild-type laboratory mice

10.1101/2021.09.29.462373 ◽

2021 ◽

Author(s):

Shannon Stone ◽

Hussin A. Rothan ◽

Janhavi P. Natekar ◽

Pratima Kumari ◽

Shaligram Sharma ◽

...

Keyword(s):

Immune Escape ◽

Mrna Levels ◽

Laboratory Mice ◽

Wild Type ◽

The Public ◽

Cytokines And Chemokines ◽

Tnf Α ◽

New Hosts ◽

High Concentrations ◽

Old Mice

AbstractThe emergence of new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants of concern poses a major threat to the public health due to possible enhanced virulence, transmissibility and immune escape. These variants may also adapt to new hosts in part through mutations in the spike protein. In this study, we evaluated the infectivity and pathogenicity of SARS-CoV-2 variants of concern in wild-type C57BL/6 mice. Six-week-old mice were inoculated intranasally with a representative virus from the original B.1 lineage or emerging B.1.1.7 and B.1.351 lineages. We also infected a group of mice with a mouse-adapted SARS-CoV-2 (MA10). Viral load and mRNA levels of multiple cytokines and chemokines were analyzed in the lung tissues on day 3 after infection. Our data show that unlike the B.1 virus, the B.1.1.7 and B.1.351 viruses are capable of infecting C57BL/6 mice and replicating at high concentrations in the lungs. The B.1.351 virus replicated to higher titers in the lungs compared to the B.1.1.7 and MA10 viruses. The levels of cytokines (IL-6, TNF-α, IL-1β) and chemokine (CCL2) were upregulated in response to the B.1.1.7 and B.1.351 infection in the lungs. Overall, these data indicate a greater potential for infectivity and adaptation to new hosts by emerging SARS-CoV-2 variants.

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Abstract P345: Overexpression of Mitochondrial Deacetylase Sirt3 Protects Endothelial Function and Attenuates Hypertension While Sirt3 Depletion Increases Oxidative Stress and Endothelial Dysfunction Due to SOD2 Hyperacetylation

Hypertension ◽

10.1161/hyp.70.suppl_1.p345 ◽

2017 ◽

Vol 70 (suppl_1) ◽

Author(s):

Anna E Dikalova ◽

Hana A Itani ◽

Arvind K Pandey ◽

David G Harrison ◽

Sergey I Dikalov

Keyword(s):

Nitric Oxide ◽

Blood Pressure ◽

Smooth Muscle ◽

Angiotensin Ii ◽

Endothelial Dysfunction ◽

Endothelial Function ◽

Knockout Mice ◽

Whole Body ◽

Wild Type ◽

Endothelial Nitric Oxide

We have recently reported SOD2 hyperacetylation and reduced Sirt3 level in human subjects with essential hypertension. We hypothesized that diminished Sirt3 expression promotes endothelial dysfunction and hypertension while Sirt3 overexpression protects endothelial function and attenuates hypertension. Indeed, hypertension was markedly increased in Sirt3 knockout (Sirt3 -/- ) in response to angiotensin II (0.7 mg/kg/day) compared with wild-type C57Bl/6J mice. Sirt3 depletion caused SOD2 inactivation due to SOD2 hyperacetylation, increased mitochondrial O 2 • and diminished endothelial nitric oxide. Angiotensin II infusion in wild-type mice was associated with Sirt3 inactivation and SOD2 hyperacetylation in aorta and kidney. To test the specific role of Sirt3 in vasculature we have generated tamoxifen-inducible endothelium specific Sirt3 knockout mice (Ec Sirt3 KO ) and tamoxifen-inducible smooth muscle specific Sirt3 knockout mice (Smc Sirt3 KO ). Deletion of Sirt3 in smooth muscle exacerbated hypertension (165 mm Hg vs 155 mm Hg in wild-type) and significantly increased mortality in angiotensin II infused Smc Sirt3 KO mice (30% vs 3% in wild-type) which was associated with higher rate of aortic aneurysm. Ec Sirt3 KO mice had elevated basal blood pressure by 12 mm Hg and hypertension was exacerbated in Ec Sirt3 KO mice accompanied by impaired vascular relaxation and reduced endothelial nitric oxide. Treatment of angiotensin II-infused Sirt3 -/- mice with SOD2 mimetic mitoTEMPO rescued endothelial-dependent relaxation and reduced blood pressure. We tested if Sirt3 overexpression protects endothelial function and attenuates angiotensin II-induced hypertension. These new mice were obtained by crossing the EIIa-cre with Sirt3flox mice resulting in constitutively increased Sirt3 in the whole body. Sirt3 overexpression abolished angiotensin II induced impairment of vasorelaxation and attenuated development of hypertension. Our data suggest that diminished Sirt3 activity leads to SOD2 hyperacetylation and contributes to the pathogenesis of hypertension. It is conceivable that Sirt3 agonists and SOD2 mimetics may have therapeutic potential in cardiovascular disease.

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