共查询到20条相似文献,搜索用时 31 毫秒
1.
Young-Lai Cho Sung-Mo Hur Ji-Yoon Kim Ji-Hee Kim Dong-Keon Lee Jongeon Choe Moo-Ho Won Kwon-Soo Ha Dooil Jeoung Sanghwa Han Sungwoo Ryoo Hansoo Lee Jeong-Ki Min Young-Guen Kwon Dong-Hyun Kim Young-Myeong Kim 《The Journal of biological chemistry》2015,290(1):467-477
Ginsenoside Rg5 is a compound newly synthesized during the steaming process of ginseng; however, its biological activity has not been elucidated with regard to endothelial function. We found that Rg5 stimulated in vitro angiogenesis of human endothelial cells, consistent with increased neovascularization and blood perfusion in a mouse hind limb ischemia model. Rg5 also evoked vasorelaxation in aortic rings isolated from wild type and high cholesterol-fed ApoE−/− mice but not from endothelial nitric-oxide synthase (eNOS) knock-out mice. Angiogenic activity of Rg5 was highly associated with a specific increase in insulin-like growth factor-1 receptor (IGF-1R) phosphorylation and subsequent activation of multiple angiogenic signals, including ERK, FAK, Akt/eNOS/NO, and Gi-mediated phospholipase C/Ca2+/eNOS dimerization pathways. The vasodilative activity of Rg5 was mediated by the eNOS/NO/cGMP axis. IGF-1R knockdown suppressed Rg5-induced angiogenesis and vasorelaxation by inhibiting key angiogenic signaling and NO/cGMP pathways. In silico docking analysis showed that Rg5 bound with high affinity to IGF-1R at the same binding site of IGF. Rg5 blocked binding of IGF-1 to its receptor with an IC50 of ∼90 nmol/liter. However, Rg5 did not induce vascular inflammation and permeability. These data suggest that Rg5 plays a novel role as an IGF-1R agonist, promoting therapeutic angiogenesis and improving hypertension without adverse effects in the vasculature. 相似文献
2.
Christopher J. Traynham Steve R. Roof Honglan Wang Robert A. Prosak Lifei Tang Serge Viatchenko-Karpinski Hsiang-Ting Ho Ira O. Racoma Dominic J. Catalano Xin Huang Yongbin Han Shang-U Kim Sandor Gyorke George E. Billman Frederick A. Villamena Mark T. Ziolo 《PloS one》2012,7(12)
Nitric oxide (NO) and superoxide (O2
−) are important cardiac signaling molecules that regulate myocyte contraction. For appropriate regulation, NO and O2
.− must exist at defined levels. Unfortunately, the NO and O2
.− levels are altered in many cardiomyopathies (heart failure, ischemia, hypertrophy, etc.) leading to contractile dysfunction and adverse remodeling. Hence, rescuing the nitroso-redox levels is a potential therapeutic strategy. Nitrone spin traps have been shown to scavenge O2
.− while releasing NO as a reaction byproduct; and we synthesized a novel, cell permeable nitrone, 2–2–3,4-dihydro-2H-pyrrole 1-oxide (EMEPO). We hypothesized that EMEPO would improve contractile function in myocytes with altered nitroso-redox levels. Ventricular myocytes were isolated from wildtype (C57Bl/6) and NOS1 knockout (NOS1−/−) mice, a known model of NO/O2
.− imbalance, and incubated with EMEPO. EMEPO significantly reduced O2
.− (lucigenin-enhanced chemiluminescence) and elevated NO (DAF-FM diacetate) levels in NOS1−/− myocytes. Furthermore, EMEPO increased NOS1−/− myocyte basal contraction (Ca2+ transients, Fluo-4AM; shortening, video-edge detection), the force-frequency response and the contractile response to β-adrenergic stimulation. EMEPO had no effect in wildtype myocytes. EMEPO also increased ryanodine receptor activity (sarcoplasmic reticulum Ca2+ leak/load relationship) and phospholamban Serine16 phosphorylation (Western blot). We also repeated our functional experiments in a canine post-myocardial infarction model and observed similar results to those seen in NOS1−/− myocytes. In conclusion, EMEPO improved contractile function in myocytes experiencing an imbalance of their nitroso-redox levels. The concurrent restoration of NO and O2
.− levels may have therapeutic potential in the treatment of various cardiomyopathies. 相似文献
3.
Winifred O. Idigo Svetlana Reilly Mei Hua Zhang Yin Hua Zhang Raja Jayaram Ricardo Carnicer Mark J. Crabtree Jean-Luc Balligand Barbara Casadei 《The Journal of biological chemistry》2012,287(52):43665-43673
Myocardial constitutive No production depends on the activity of both endothelial and neuronal NOS (eNOS and nNOS, respectively). Stimulation of myocardial β3-adrenergic receptor (β3-AR) produces a negative inotropic effect that is dependent on eNOS. We evaluated whether nNOS also plays a role in β3-AR signaling and found that the β3-AR-mediated reduction in cell shortening and [Ca2+]i transient amplitude was abolished both in eNOS−/− and nNOS−/− left ventricular (LV) myocytes and in wild type LV myocytes after nNOS inhibition with S-methyl-l-thiocitrulline. LV superoxide (O2˙̄) production was increased in nNOS−/− mice and reduced by l-Nω-nitroarginine methyl ester (l-NAME), indicating uncoupling of eNOS activity. eNOS S-glutathionylation and Ser-1177 phosphorylation were significantly increased in nNOS−/− myocytes, whereas myocardial tetrahydrobiopterin, eNOS Thr-495 phosphorylation, and arginase activity did not differ between genotypes. Although inhibitors of xanthine oxidoreductase (XOR) or NOX2 NADPH oxidase caused a similar reduction in myocardial O2˙̄, only XOR inhibition reduced eNOS S-glutathionylation and Ser-1177 phosphorylation and restored both eNOS coupled activity and the negative inotropic and [Ca2+]i transient response to β3-AR stimulation in nNOS−/− mice. In summary, our data show that increased O2˙̄ production by XOR selectively uncouples eNOS activity and abolishes the negative inotropic effect of β3-AR stimulation in nNOS−/− myocytes. These findings provide unequivocal evidence of a functional interaction between the myocardial constitutive NOS isoforms and indicate that aspects of the myocardial phenotype of nNOS−/− mice result from disruption of eNOS signaling. 相似文献
4.
Bhavani Gopalakrishnan Kevin M. Nash Murugesan Velayutham Frederick A. Villamena 《Journal of visualized experiments : JoVE》2012,(66)
Reactive nitrogen/oxygen species (ROS/RNS) at low concentrations play an important role in regulating cell function, signaling, and immune response but in unregulated concentrations are detrimental to cell viability1, 2. While living systems have evolved with endogenous and dietary antioxidant defense mechanisms to regulate ROS generation, ROS are produced continuously as natural by-products of normal metabolism of oxygen and can cause oxidative damage to biomolecules resulting in loss of protein function, DNA cleavage, or lipid peroxidation3, and ultimately to oxidative stress leading to cell injury or death4. Superoxide radical anion (O2•-) is the major precursor of some of the most highly oxidizing species known to exist in biological systems such as peroxynitrite and hydroxyl radical. The generation of O2•- signals the first sign of oxidative burst, and therefore, its detection and/or sequestration in biological systems is important. In this demonstration, O2•- was generated from polymorphonuclear neutrophils (PMNs). Through chemotactic stimulation with phorbol-12-myristate-13-acetate (PMA), PMN generates O2•- via activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase5. Nitric oxide (NO) synthase which comes in three isoforms, as inducible-, neuronal- and endothelial-NOS, or iNOS, nNOS or eNOS, respectively, catalyzes the conversion of L- arginine to L-citrulline, using NADPH to produce NO6. Here, we generated NO from endothelial cells. Under oxidative stress conditions, eNOS for example can switch from producing NO to O2•- in a process called uncoupling, which is believed to be caused by oxidation of heme7 or the co-factor, tetrahydrobiopterin (BH4)8.There are only few reliable methods for the detection of free radicals in biological systems but are limited by specificity and sensitivity. Spin trapping is commonly used for the identification of free radicals and involves the addition reaction of a radical to a spin trap forming a persistent spin adduct which can be detected by electron paramagnetic resonance (EPR) spectroscopy. The various radical adducts exhibit distinctive spectrum which can be used to identify the radicals being generated and can provide a wealth of information about the nature and kinetics of radical production9.The cyclic nitrones, 5,5-dimethyl-pyrroline-N-oxide, DMPO10, the phosphoryl-substituted DEPMPO11, and the ester-substituted, EMPO12 and BMPO13, have been widely employed as spin traps--the latter spin traps exhibiting longer half-lives for O2•- adduct. Iron (II)-N-methyl-D-glucamine dithiocarbamate, Fe(MGD)2 is commonly used to trap NO due to high rate of adduct formation and the high stability of the spin adduct14. 相似文献
5.
Endothelial dysfunction is associated with increase in oxidative stress and low NO bioavailability. The endothelial NO synthase (eNOS) uncoupling is considered an important factor in endothelial cell oxidative stress. Under increased oxidative stress, the eNOS cofactor tetrahydrobiopterin (BH4) is oxidized to dihydrobiopterin, which competes with BH4 for binding to eNOS, resulting in eNOS uncoupling and reduction in NO production. The importance of the ratio of BH4 to oxidized biopterins versus absolute levels of total biopterin in determining the extent of eNOS uncoupling remains to be determined. We have developed a computational model to simulate the kinetics of the biochemical pathways of eNOS for both NO and O2•− production to understand the roles of BH4 availability and total biopterin (TBP) concentration in eNOS uncoupling. The downstream reactions of NO, O2•−, ONOO−, O2, CO2, and BH4 were also modeled. The model predicted that a lower [BH4]/[TBP] ratio decreased NO production but increased O2•− production from eNOS. The NO and O2•− production rates were independent above 1.5 μM [TBP]. The results indicate that eNOS uncoupling is a result of a decrease in [BH4]/[TBP] ratio, and a supplementation of BH4 might be effective only when the [BH4]/[TBP] ratio increases. The results from this study will help us understand the mechanism of endothelial dysfunction. 相似文献
6.
GeumHwa Lee TheHiep Hoang EunSoo Jung SuJin Jung SeongKyu Han MyoungJa Chung SooWan Chae HanJung Chae 《Aging cell》2020,19(12)
Endothelial dysfunction is one of the main age‐related arterial phenotypes responsible for cardiovascular disease (CVD) in older adults. This endothelial dysfunction results from decreased bioavailability of nitric oxide (NO) arising downstream of endothelial oxidative stress. In this study, we investigated the protective effect of anthocyanins and the underlying mechanism in rat thoracic aorta and human vascular endothelial cells in aging models. In vitro, cyanidin‐3‐rutinoside (C‐3‐R) and cyanidin‐3‐glucoside (C‐3‐G) inhibited the d‐galactose (d‐gal)‐induced senescence in human endothelial cells, as indicated by reduced senescence‐associated‐β‐galactosidase activity, p21, and p16INK4a. Anthocyanins blocked d‐gal‐induced reactive oxygen species (ROS) formation and NADPH oxidase activity. Anthocyanins reversed d‐gal‐mediated inhibition of endothelial nitric oxide synthase (eNOS) serine phosphorylation and SIRT1 expression, recovering NO level in endothelial cells. Also, SIRT1‐mediated eNOS deacetylation was shown to be involved in anthocyanin‐enhanced eNOS activity. In vivo, anthocyanin‐rich mulberry extract was administered to aging rats for 8 weeks. In vivo, mulberry extract alleviated endothelial senescence and oxidative stress in the aorta of aging rats. Consistently, mulberry extract also raised serum NO levels, increased phosphorylation of eNOS, increased SIRT1 expression, and reduced nitrotyrosine in aortas. The eNOS acetylation was higher in the aging group and was restored by mulberry extract treatment. Similarly, SIRT1 level associated with eNOS decreased in the aging group and was restored in aging plus mulberry group. These findings indicate that anthocyanins protect against endothelial senescence through enhanced NO bioavailability by regulating ROS formation and reducing eNOS uncoupling. 相似文献
7.
Yasumasa Ikeda Ken-ichi Aihara Sumiko Yoshida Takashi Iwase Soichiro Tajima Yuki Izawa-Ishizawa Yoshitaka Kihira Keisuke Ishizawa Shuhei Tomita Koichiro Tsuchiya Masataka Sata Masashi Akaike Shigeaki Kato Toshio Matsumoto Toshiaki Tamaki 《The Journal of biological chemistry》2012,287(41):34256-34263
We previously clarified that heparin cofactor II (HCII), a serine proteinase inhibitor, exerts various protective actions on cardiovascular diseases in both experimental and clinical studies. In the present study, we aimed to clarify whether HCII participates in the regulation of angiogenesis. Male heterozygous HCII-deficient (HCII+/−) mice and male littermate wild-type (HCII+/+) mice at the age of 12–16 weeks were subjected to unilateral hindlimb ligation surgery. Laser speckle blood flow analysis showed that blood flow recovery in response to hindlimb ischemia was delayed in HCII+/− mice compared with that in HCII+/+ mice. Capillary number, arteriole number, and endothelial nitric-oxide synthase (eNOS), AMP-activated protein kinase (AMPK), and liver kinase B1 (LKB1) phosphorylation in ischemic muscles were decreased in HCII+/− mice. Human purified HCII (h-HCII) administration almost restored blood flow recovery, capillary density, and arteriole number as well as phosphorylation levels of eNOS, AMPK, and LKB1 in ischemic muscles of HCII+/− mice. Although treatment with h-HCII increased phosphorylation levels of eNOS, AMPK, and LKB1 in human aortic endothelial cells (HAECs), the h-HCII-induced eNOS phosphorylation was abolished by compound C, an AMPK inhibitor, and by AMPK siRNA. In a similar fashion, tube formation, proliferation, and migration of HAECs were also promoted by h-HCII treatment and were abrogated by pretreatment with compound C. HCII potentiates the activation of vascular endothelial cells and the promotion of angiogenesis in response to hindlimb ischemia via an AMPK-eNOS signaling pathway. These findings suggest that HCII is a novel therapeutic target for treatment of patients with peripheral circulation insufficiency. 相似文献
8.
Nicholas K.H. Khoo Volker Rudolph Marsha P. Cole Franca Golin-Bisello Francisco J. Schopfer Steven R. Woodcock Carlos Batthyany Bruce A. Freeman 《Free radical biology & medicine》2010,48(2):230-239
Reactive oxygen species mediate a decrease in nitric oxide (NO) bioavailability and endothelial dysfunction, with secondary oxidized and nitrated by-products of these reactions contributing to the pathogenesis of numerous vascular diseases. While oxidized lipids and lipoproteins exacerbate inflammatory reactions in the vasculature, in stark contrast the nitration of polyunsaturated fatty acids and complex lipids yields electrophilic products that exhibit pluripotent anti-inflammatory signaling capabilities acting via both cGMP-dependent and -independent mechanisms. Herein we report that nitro-oleic acid (OA-NO2) treatment increases expression of endothelial nitric oxide synthase (eNOS) and heme oxygenase 1 (HO-1) in the vasculature, thus transducing vascular protective effects associated with enhanced NO production. Administration of OA-NO2 via osmotic pump results in a significant increase in eNOS and HO-1 mRNA in mouse aortas. Moreover, HPLC-MS/MS analysis showed that NO2-FAs are rapidly metabolized in cultured endothelial cells (ECs) and treatment with NO2-FAs stimulated the phosphorylation of eNOS at Ser1179. These posttranslational modifications of eNOS, in concert with elevated eNOS gene expression, contributed to an increase in endothelial NO production. In aggregate, OA-NO2-induced eNOS and HO-1 expression by vascular cells can induce beneficial effects on endothelial function and provide a new strategy for treating various vascular inflammatory and hypertensive disorders. 相似文献
9.
Nicolle Kr?nkel Stephen Paul Armstrong Craig Alexander McArdle Colin Dayan Paolo Madeddu 《PloS one》2010,5(6)
Aims/Hypothesis
We aimed to understand early alterations in kinin-mediated migration of circulating angio-supportive cells and dysfunction of kinin-sensitive cells in type-1 diabetic (T1D) patients before the onset of cardiovascular disease.Methods
Total mononuclear cells (MNC) were isolated from peripheral blood of 28 T1D patients free from cardiovascular complications except mild background retinopathy (age: 34.8±1.6 years, HbA1C: 7.9±0.2%) and 28 age- and sex-matched non-diabetic controls (H). We tested expression of kinin receptors by flow cytometry and migratory capacity of circulating monocytes and progenitor cells towards bradykinin (BK) in transwell migration assays. MNC migrating towards BK (BKmig) were assessed for capacity to support endothelial cell function in a matrigel assay, as well as generation of nitric oxide (NO) and superoxide (O2 −*) by using the fluorescent probes diaminofluorescein and dihydroethidium.Results
CD14hiCD16neg, CD14hiCD16pos and CD14loCD16pos monocytes and circulating CD34pos progenitor cells did not differ between T1D and H subjects in their kinin receptor expression and migration towards BK. T1D BKmig failed to generate NO upon BK stimulation and supported endothelial cell network formation less efficiently than H BKmig. In contrast, O2 −* production was similar between groups. High glucose disturbed BK-induced NO generation by MNC-derived cultured angiogenic cells.Conclusions/Interpretation
Our data point out alterations in kinin-mediated functions of circulating MNC from T1D patients, occurring before manifest macrovascular damage or progressed microvascular disease. Functional defects of MNC recruited to the vessel wall might compromise endothelial maintenance, initially without actively promoting endothelial damage, but rather by lacking supportive contribution to endothelial regeneration and healing. 相似文献10.
Novensà L Novella S Medina P Segarra G Castillo N Heras M Hermenegildo C Dantas AP 《PloS one》2011,6(9):e25335
Aims
Aging is among the major causes for the lack of cardiovascular protection by estrogen (E2) during postmenopause. Our study aims to determine the mechanisms whereby aging changes E2 effects on nitric oxide (NO) production in a mouse model of accelerated senescence (SAM).Methods and Results
Although we found no differences on NO production in females SAM prone (SAMP, aged) compared to SAM resistant (SAMR, young), by either DAF-2 fluorescence or plasmatic nitrite/nitrate (NO2/NO3), in both cases, E2 treatment increased NO production in SAMR but had no effect in SAMP. Those results are in agreement with changes of eNOS protein and gene expression. E2 up-regulated eNOS expression in SAMR but not in SAMP. E2 is also known to increase NO by decreasing its catabolism by superoxide anion (O2 -). Interestingly, E2 treatment decreased O2 − production in young females, while increased O2 − in aged ones. Furthermore, we observed that aging changed expression ratio of estrogen receptors (ERβ/ERα) and levels of DNA methylation. Increased ratio ERβ/ERα in aged females is associated to a lack of estrogen modulation of NO production and with a reversal in its antioxidant effect to a pro-oxidant profile.Conclusions
Together, our data suggest that aging has detrimental effects on E2-mediated benefits on NO bioavailability, partially by affecting the ability of E2 to induce up regulation of eNOS and decrease of O2 −. These modifications may be associated to aging-mediated modifications on global DNA methylation status, but not to a specific methylation at 5′flanking region of ERα gene. 相似文献11.
Karthik Mallilankaraman Rajesh Kumar Gandhirajan Brian J. Hawkins Muniswamy Madesh 《Journal of visualized experiments : JoVE》2011,(58)
Oxidative stress has been implicated in a number of pathologic conditions including ischemia/reperfusion damage and sepsis. The concept of oxidative stress refers to the aberrant formation of ROS (reactive oxygen species), which include O2•-, H2O2, and hydroxyl radicals. Reactive oxygen species influences a multitude of cellular processes including signal transduction, cell proliferation and cell death1-6. ROS have the potential to damage vascular and organ cells directly, and can initiate secondary chemical reactions and genetic alterations that ultimately result in an amplification of the initial ROS-mediated tissue damage. A key component of the amplification cascade that exacerbates irreversible tissue damage is the recruitment and activation of circulating inflammatory cells. During inflammation, inflammatory cells produce cytokines such as tumor necrosis factor-α (TNFα) and IL-1 that activate endothelial cells (EC) and epithelial cells and further augment the inflammatory response7. Vascular endothelial dysfunction is an established feature of acute inflammation. Macrophages contribute to endothelial dysfunction during inflammation by mechanisms that remain unclear. Activation of macrophages results in the extracellular release of O2•- and various pro-inflammatory cytokines, which triggers pathologic signaling in adjacent cells8. NADPH oxidases are the major and primary source of ROS in most of the cell types. Recently, it is shown by us and others9,10 that ROS produced by NADPH oxidases induce the mitochondrial ROS production during many pathophysiological conditions. Hence measuring the mitochondrial ROS production is equally important in addition to measuring cytosolic ROS. Macrophages produce ROS by the flavoprotein enzyme NADPH oxidase which plays a primary role in inflammation. Once activated, phagocytic NADPH oxidase produces copious amounts of O2•- that are important in the host defense mechanism11,12. Although paracrine-derived O2•- plays an important role in the pathogenesis of vascular diseases, visualization of paracrine ROS-induced intracellular signaling including Ca2+ mobilization is still hypothesis. We have developed a model in which activated macrophages are used as a source of O2•- to transduce a signal to adjacent endothelial cells. Using this model we demonstrate that macrophage-derived O2•- lead to calcium signaling in adjacent endothelial cells. 相似文献
12.
Background
The aging gene p66Shc, is an important mediator of oxidative stress-induced vascular dysfunction and disease. In cultured human aortic endothelial cells (HAEC), p66Shc deletion increases endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) bioavailability via protein kinase B. However, the putative role of the NO pathway on p66Shc activation remains unclear. This study was designed to elucidate the regulatory role of the eNOS/NO pathway on p66Shc activation.Methods and Results
Incubation of HAEC with oxidized low density lipoprotein (oxLDL) led to phosphorylation of p66Shc at Ser-36, resulting in an enhanced production of superoxide anion (O2 -). In the absence of oxLDL, inhibition of eNOS by small interfering RNA or L-NAME, induced p66Shc phosphorylation, suggesting that basal NO production inhibits O2 - production. oxLDL-induced, p66Shc-mediated O2- was prevented by eNOS inhibition, suggesting that when cells are stimulated with oxLDL eNOS is a source of reactive oxygen species. Endogenous or exogenous NO donors, prevented p66Shc activation and reduced O2- production. Treatment with tetrahydrobiopterin, an eNOS cofactor, restored eNOS uncoupling, prevented p66Shc activation, and reduced O2- generation. However, late treatment with tetrahydropterin did not yield the same result suggesting that eNOS uncoupling is the primary source of reactive oxygen species.Conclusions
The present study reports that in primary cultured HAEC treated with oxLDL, p66Shc-mediated oxidative stress is derived from eNOS uncoupling. This finding contributes novel information on the mechanisms of p66Shc activation and its dual interaction with eNOS underscoring the importance eNOS uncoupling as a putative antioxidant therapeutical target in endothelial dysfunction as observed in cardiovascular disease. 相似文献13.
Weiyu Chen Yuhong Cui Shuhui Zheng Jinghe Huang Ping Li Tommaso Simoncini Yongfu Zhang Xiaodong Fu 《PloS one》2015,10(3)
The endogenous estradiol metabolite 2-methoxyestradiol (2-ME) reduces atherosclerotic lesion formation, while the underlying mechanisms remain obscure. In this work, we investigated the vasodilatory effect of 2-ME and the role of nitric oxide (NO) involved. In vivo studies using noninvasive tail-cuff methods showed that 2-ME decreased blood pressure in Sprague Dawley rats. Furthermore, in vitro studies showed that cumulative addition of 2-ME to the aorta caused a dose- and endothelium-dependent vasodilation. This effect was unaffected by the pretreatment with the pure estrogen receptor antagonist ICI 182,780, but was largely impaired by endothelial nitric oxide synthase (eNOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME) or by phosphoinositide 3-kinase (PI3K) inhibitor wortmannin (WM). Moreover, 2-ME(10−7 ∼10−5 M)enhanced phosphorylation of Akt and eNOS and promoted NO release from cultured human umbilical endothelial cells (HUVECs). These effects were blocked by PI3K inhibitor WM, or by the transfection with Akt specific siRNA, indicating that endothelial Akt/eNOS/NO cascade plays a crucial role in 2-ME-induced vasodilation. The peroxisome proliferator-activated receptor γ (PPARγ) mRNA and protein expression were detected in HUVECs and the antagonist GW9662 or the transfection with specific PPARγ siRNA inhibited 2-ME-induced eNOS and Akt phosphorylation, leading to the impairment of NO production and vasodilation. In conclusion, 2-ME induces vasodilation by stimulating NO release. These actions may be mediated by PPARγ and the subsequent activation of Akt/eNOS cascade in vascular endothelial cells. 相似文献
14.
Increasing evidences have accumulated that endothelial dysfunction is involved in the pathogenesis of hypertension. Peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) has been identified as an essential factor that protects against endothelial dysfunction in vascular pathologies. However, the functional role of PGC-1α in hypertension is not well understood. Using an adenovirus infection model, we tested the hypothesis that PGC-1α overexpression retards the progression of hypertension in deoxycorticosterone acetate (DOCA)-salt mice model through preservation of the function of endothelium. We first demonstrated that PGC-1α expression not only in conductance and resistance arteries but also in endothelial cells was decreased after DOCA-salt treatment. In PGC-1α adenovirus-infected mice, the elevation of blood pressure in DOCA-salt mice was attenuated, as determined using tail-cuff measurement. Furthermore, PGC-1α overexpression inhibited the decrease in nitric oxide (NO) generation and the increase in superoxide anion (O2−) production in DOCA-salt-treated mice, in parallel with improved endothelium-dependent relaxation. Rather than affecting endothelial NO synthase (eNOS) total expression and phosphorylation, PGC-1α significantly inhibited eNOS uncoupling, as evidenced by increased eNOS homodimerization, BH4 levels, GTP-cyclohydrolase 1 (GTPCH1) and dihydrofolate reductase (DHFR) expression and heat-shock protein (Hsp)90–eNOS interaction. Our findings demonstrate that PGC-1α overexpression preserves eNOS coupling, enhances NO generation, improves endothelium-dependent relaxation and thus lowers blood pressure, suggesting that up-regulation of PGC-1α may be a novel strategy to prevent and treat hypertension. 相似文献
15.
《Free radical research》2013,47(12):1496-1513
In endothelial cell dysfunction, the uncoupling of eNOS results in higher superoxide (O2??) and lower NO production and a reduction in NO availability. Superoxide reacts with NO to form a potent oxidizing agent peroxynitrite (ONOO?) resulting in nitrosative and nitroxidative stresses and dismutates to form hydrogen peroxide. Studies have shown superoxide dismutase (SOD) plays an important role in reduction of O2?? and ONOO? during eNOS uncoupling. However, the administration or over-expression of SOD was ineffective or displayed deleterious effects in some cases. An understanding of interactions of the two enzyme systems eNOS and SOD is important in determining endothelial cell function. We analyzed complex biochemical interactions involving eNOS and SOD in eNOS uncoupling. A computational model of biochemical pathway of the eNOS-related NO and O2?? production and downstream reactions involving NO, O2??, ONOO?, H2O2 and SOD was developed. The effects of SOD concentration on the concentration profiles of NO, O2??, ONOO? and H2O2 in eNOS coupling/uncoupling were investigated. The results include (i) SOD moderately improves NO production and concentration during eNOS uncoupling, (ii) O2?? production rate is independent of SOD concentration, (iii) Increase in SOD concentration from 0.1 to 100 μM reduces O2?? concentration by 90% at all [BH4]/[TBP] ratios, (iv) SOD reduces ONOO? concentration and increases H2O2 concentration during eNOS uncoupling, (v) Catalase can reduce H2O2 concentration and (vi) Dismutation rate by SOD is the most sensitive parameter during eNOS uncoupling. Thus, SOD plays a dual role in eNOS uncoupling as an attenuator of nitrosative/nitroxidative stress and an augmenter of oxidative stress. 相似文献
16.
Sona Cacanyiova Frantisek Kristek Maria Gerova Peter Krenek Jan Klimas 《Nitric oxide》2009,20(4):304-310
While the unequivocal pattern of endothelial nitric oxide (NO) synthase (eNOS) inhibition in cardiovascular control has been recognised, the role of NO produced by neuronal NOS (nNOS) remains unclear. The purpose of the present study was to describe the cardiovascular effects of NO production interference by inhibition of nNOS with 7-nitroindazole (7-NI). Wistar rats (10 weeks old) were used: control and experimental rats were administered 7-NI 10 mg/kg b.w./day in drinking water for 6 weeks. Systolic blood pressure (BP) was measured by the tail-cuff plethysmographic method. Isolated thoracic aortas (TAs) were used to study vasomotor activity of the conduit artery in vitro. The BP response of anaesthetised animals was used to follow the cardiovascular-integrated response in vivo. Geometry of the TA was measured after perfusion fixation (120 mm Hg) by light microscopy. Expression of eNOS was measured in the TA by immunoblot analysis. Although 6 weeks of nNOS inhibition did not alter systolic BP, the heart/body weight ratio was decreased. Relaxation of the TA in response to acetylcholine (10−9–10−5 mol/L) was moderately inhibited. However, no difference in the BP hypotensive response after acetylcholine (0.1, 1, 10 μg) was observed. The contraction of TA in response to noradrenaline (10−10–10−5 mol/L), and the BP pressor response to noradrenaline (0.1, 1 μg) was attenuated. The inner diameter of the TA was increased, and the wall thickness, wall cross-sectional area, and wall thickness/inner diameter ratio were decreased. The expression of eNOS in the TA was increased. In summary, cardiac and TA wall hypotrophy, underlined by decreased contractile efficiency, were observed. The results suggested that two constitutive forms of NOS (nNOS, eNOS) likely participate in regulation of cardiovascular tone by different mechanisms. 相似文献
17.
Sai Wang Seto Smriti M. Krishna Hongyou Yu David Liu Surabhi Khosla Jonathan Golledge 《PloS one》2013,8(3)
Objective
The angiotensin II (AngII)-infused apolipoprotein E-deficient (ApoE−/−) mouse model is widely used to study atherosclerosis and abdominal aortic aneurysm. An increase in blood pressure has been reported in this model however the underlying mechanism has not been fully explored. In this study, we investigated whether vasomotor dysfunction develops in AngII-infused ApoE−/− mice and the underlying mechanism involved.Methods
ApoE−/− mice were infused with vehicle (distilled water) or AngII subcutaneously for 14 days. Blood pressure and heart rate were measured using the non-invasive tail cuff method. Aortic vascular reactivity and expression of key proteins (endothelial nitric oxide synthase (eNOS), phospho-eNOS and caveolin-1) were assessed using tension myography and Western blotting respectively. Plasma nitric oxide (NO) level was estimated using a colorimetric assay.Results
AngII infusion caused a time-dependent increase in blood pressure (P<0.001). Aortas from AngII-infused mice were significantly less responsive to acetylcholine-induced endothelium-dependent relaxation when compared to aortas from mice infused with vehicle control (P<0.05). Contractile responses to phenylephrine (P<0.01) and potassium chloride (P<0.001) were significantly enhanced in aortas from AngII-infused mice. eNOS phosphorylation was significantly decreased in the aorta of AngII-infused mice (P<0.05). Aortic caveolin-1 protein expression was significantly increased in AngII-infused mice (P<0.05). Plasma nitrate/nitrite level was significantly reduced in AngII-infused mice (P<0.05). Pharmacological disruption of caveolae using methyl-β-cyclodextrin (MβCD) in isolated aortas from AngII-infused mice caused a significant leftward shift of the acetylcholine-induced relaxation concentration-response curve when compared to vehicle control (P<0.05).Conclusion
Upregulation of caveolin-1 protein expression and reduced NO bioavailability contributes to aortic endothelial dysfunction in AngII-infused ApoE−/− mice. 相似文献18.
Jian Zhao 《Plant signaling & behavior》2007,2(6):544-547
Programmed cell death (PCD) is an integrated cellular process occurring in plant growth, development, and defense responses to facilitate normal growth and development and better survival against various stresses as a whole. As universal toxic chemicals in plant and animal cells, reactive oxygen or nitrogen species (ROS or RNS), mainly superoxide anion (O2−•), hydrogen peroxide (H2O2) or nitric oxide (•NO), have been studied extensively for their roles in PCD induction. Physiological and genetic studies have convincingly shown their essential roles. However, the details and mechanisms by which ROS and •NO interplay and induce PCD are not well understood. Our recent study on Cupressus lusitanica culture cell death revealed the elicitor-induced co-accumulation of ROS and •NO and interactions between •NO and H2O2 or O2-• in different ways to regulate cell death. •NO and H2O2 reciprocally enhanced the production of each other whereas •NO and O2−• showed reciprocal suppression on each other''s production. It was the interaction between •NO and O2-• but not between •NO and H2O2 that induced PCD, probably through peroxynitrite (ONOO−). In this addendum, some unsolved issues in the study were discussed based on recent studies on the complex network of ROS and •NO leading to PCD in animals and plants.Key Words: cell death, nitric oxide, reactive oxygen species, interaction, posttranslational modification 相似文献
19.
Robinson JM 《Plant physiology》1990,92(3):862-865
It was hypothesized previously that an O2 inhibition of NO2− photoreduction would reflect a competition between O2 and NO2− for electrons from ferredoxin at the site of plastid nitrite reductase. In order to test this in vivo, intact spinach (Spinacia oleracea L.) leaf chloroplast and mesophyll cell isolates held in high light were aerated with streams of 20% O2/80% N2 (250 micromolar O2 in aqueous solution) or, alternatively, streams of 100% N2. Bicarbonate plus CO2 and NO2− were supplied to reaction mixtures at levels just sufficient to promote maximal assimilations of CO2 and NO2−. In chloroplast isolates, there was a 9 to 30% O2 inhibition of NO2− reduction while there were high rates of CO2 fixation. In spinach and soybean (Glycine max) leaf cell isolates, NO2− photoreduction rates were 10 to 55% inhibited by O2 at near ambient levels. It is possible that O2 may compete, albeit weakly, with NO2− (nitrite reductase) for equivalents derived from reduced ferredoxin. Also, O2 may oxidize sulfhydryl groups on nitrite reductase which are involved in substrate binding and/or activation. 相似文献
20.
Ifeanyi U. Anidi Laura E. Servinsky Otgonchimeg Rentsendorj R. Scott Stephens Alan L. Scott David B. Pearse 《PloS one》2013,8(8)
Severe malaria can trigger acute lung injury characterized by pulmonary edema resulting from increased endothelial permeability. However, the mechanism through which lung fluid conductance is altered during malaria remains unclear. To define the role that the scavenger receptor CD36 may play in mediating this response, C57BL/6J (WT) and CD36−/− mice were infected with P. berghei ANKA and monitored for changes in pulmonary endothelial barrier function employing an isolated perfused lung system. WT lungs demonstrated a >10-fold increase in two measures of paracellular fluid conductance and a decrease in the albumin reflection coefficient (σalb) compared to control lungs indicating a loss of barrier function. In contrast, malaria-infected CD36−/− mice had near normal fluid conductance but a similar reduction in σalb. In WT mice, lung sequestered iRBCs demonstrated production of reactive oxygen species (ROS). To determine whether knockout of CD36 could protect against ROS-induced endothelial barrier dysfunction, mouse lung microvascular endothelial monolayers (MLMVEC) from WT and CD36−/− mice were exposed to H2O2. Unlike WT monolayers, which showed dose-dependent decreases in transendothelial electrical resistance (TER) from H2O2 indicating loss of barrier function, CD36−/− MLMVEC demonstrated dose-dependent increases in TER. The differences between responses in WT and CD36−/− endothelial cells correlated with important differences in the intracellular compartmentalization of the CD36-associated Fyn kinase. Malaria infection increased total lung Fyn levels in CD36−/− lungs compared to WT, but this increase was due to elevated production of the inactive form of Fyn further suggesting a dysregulation of Fyn-mediated signaling. The importance of Fyn in CD36-dependent endothelial signaling was confirmed using in vitro Fyn knockdown as well as Fyn−/− mice, which were also protected from H2O2- and malaria-induced lung endothelial leak, respectively. Our results demonstrate that CD36 and Fyn kinase are critical mediators of the increased lung endothelial fluid conductance caused by malaria infection. 相似文献