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Shimazu T, Otani H, Yoshioka K, Fujita M, Okazaki T, Iwasaka T. Sepiapterin enhances angiogenesis and functional recovery in mice after myocardial infarction. Am J Physiol Heart Circ Physiol 2011; 301:H2061-72. [PMID: 21890687 DOI: 10.1152/ajpheart.00525.2011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Uncoupling of nitric oxide synthase (NOS) has been implicated in left ventricular (LV) remodeling and dysfunction after myocardial infarction (MI). We hypothesized that inducible NOS (iNOS) plays a crucial role in LV remodeling after MI, depending on its coupling status. MI was created in wild-type, iNOS-knockout (iNOS(-/-)), endothelial NOS-knockout (eNOS(-/-)), and neuronal NOS-knockout (nNOS(-/-)) mice. iNOS and nNOS expressions were increased after MI associated with an increase in nitrotyrosine formation. The area of myocardial fibrosis and LV end-diastolic volume and ejection fraction were more deteriorated in eNOS(-/-) mice compared with other genotypes of mice 4 wk after MI. The expression of GTP cyclohydrolase was reduced, and tetrahydrobiopterin (BH(4)) was depleted in the heart after MI. Oral administration of sepiapterin after MI increased dihydrobiopterin (BH(2)), BH(4), and BH(4)-to-BH(2) ratio in the infarcted but not sham-operated heart. The increase in BH(4)-to-BH(2) ratio was associated with inhibition of nitrotyrosine formation and an increase in nitrite plus nitrate. However, this inhibition of NOS uncoupling was blunted in iNOS(-/-) mice. Sepiapterin increased capillary density and prevented LV remodeling and dysfunction after MI in wild-type, eNOS(-/-), and nNOS(-/-) but not iNOS(-/-) mice. N(ω)-nitro-L-arginine methyl ester abrogated sepiapterin-induced increase in nitrite plus nitrate and angiogenesis and blocked the beneficial effects of sepiapterin on LV remodeling and function. These results suggest that sepiapterin enhances angiogenesis and functional recovery after MI by activating the salvage pathway for BH(4) synthesis and increasing bioavailable nitric oxide predominantly derived from iNOS.
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Affiliation(s)
- Takayuki Shimazu
- Second Department of Internal Medicine, Kansai Medical University, Moriguchi City, Japan
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102
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Okazaki T, Otani H, Shimazu T, Yoshioka K, Fujita M, Iwasaka T. Ascorbic acid and N-acetyl cysteine prevent uncoupling of nitric oxide synthase and increase tolerance to ischemia/reperfusion injury in diabetic rat heart. Free Radic Res 2011; 45:1173-83. [PMID: 21756052 DOI: 10.3109/10715762.2011.605361] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Oxidative stress may cause a loss of tetrahydrobiopterin (BH4), a co-factor of nitric oxide synthase (NOS), decrease the bioavailability of NO and aggravate ischemia/reperfusion (I/R) injury in diabetic heart. We hypothesized that ascorbic acid (AA) and N-acetyl cysteine (NAC) protect the diabetic heart from I/R injury by increasing BH4/dihydrobiopterin (BH2) ratio and inhibiting uncoupling of NOS. Diabetes mellitus was induced in rats by streptozotocin treatment, and the hearts were isolated and perfused. BH4 and BH4/BH2 ratio decreased in the diabetic heart associated with increased production of superoxide and nitrotyrosine (NT). Treatment with AA or NAC significantly increased BH4/BH2 ratio in the diabetic heart associated with decreased production of superoxide and NT and increased generation of nitrate plus nitrite (NOx). Pre-treatment with AA or NAC before 30 min ischemia followed by 120 min reperfusion improved left ventricular (LV) function and reduced infarct size in the diabetic but not non-diabetic hearts. The NOS inhibitor, L-NAME, inhibited the increase in the generation of superoxide, NT and NOx, but aggravated LV function and increased infarct size in the diabetic heart. L-NAME also abrogated the increase in NOx and improvement of LV function and the infarct size-limiting effect induced by AA or NAC in the diabetic heart. These results suggest that AA and NAC increase BH4/BH2 ratio and prevent NOS uncoupling in the diabetic heart. Resultant increase in the bioavailability of NO renders the diabetic heart toleratant to I/R injury.
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Affiliation(s)
- Toru Okazaki
- Second Department of Internal Medicine, Kansai Medical University, Moriguchi City, Japan
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103
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Schuhmacher S, Oelze M, Bollmann F, Kleinert H, Otto C, Heeren T, Steven S, Hausding M, Knorr M, Pautz A, Reifenberg K, Schulz E, Gori T, Wenzel P, Münzel T, Daiber A. Vascular dysfunction in experimental diabetes is improved by pentaerithrityl tetranitrate but not isosorbide-5-mononitrate therapy. Diabetes 2011; 60:2608-16. [PMID: 21844097 PMCID: PMC3178293 DOI: 10.2337/db10-1395] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
OBJECTIVE Diabetes is associated with vascular oxidative stress, activation of NADPH oxidase, and uncoupling of nitric oxide (NO) synthase (endothelial NO synthase [eNOS]). Pentaerithrityl tetranitrate (PETN) is an organic nitrate with potent antioxidant properties via induction of heme oxygenase-1 (HO-1). We tested whether treatment with PETN improves vascular dysfunction in the setting of experimental diabetes. RESEARCH DESIGN AND METHODS After induction of hyperglycemia by streptozotocin (STZ) injection (60 mg/kg i.v.), PETN (15 mg/kg/day p.o.) or isosorbide-5-mononitrate (ISMN; 75 mg/kg/day p.o.) was fed to Wistar rats for 7 weeks. Oxidative stress was assessed by optical methods and oxidative protein modifications, vascular function was determined by isometric tension recordings, protein expression was measured by Western blotting, RNA expression was assessed by quantitative RT-PCR, and HO-1 promoter activity in stable transfected cells was determined by luciferase assays. RESULTS PETN, but not ISMN, improved endothelial dysfunction. NADPH oxidase and serum xanthine oxidase activities were significantly reduced by PETN but not by ISMN. Both organic nitrates had minor effects on the expression of NADPH oxidase subunits, eNOS and dihydrofolate reductase (Western blotting). PETN, but not ISMN, normalized the expression of GTP cyclohydrolase-1, extracellular superoxide dismutase, and S-glutathionylation of eNOS, thereby preventing eNOS uncoupling. The expression of the antioxidant enzyme, HO-1, was increased by STZ treatment and further upregulated by PETN, but not ISMN, via activation of the transcription factor NRF2. CONCLUSIONS In contrast to ISMN, the organic nitrate, PETN, improves endothelial dysfunction in diabetes by preventing eNOS uncoupling and NADPH oxidase activation, thereby reducing oxidative stress. Thus, PETN therapy may be suited to treat patients with cardiovascular complications of diabetes.
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Affiliation(s)
- Swenja Schuhmacher
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
- Center of Thrombosis and Hemostasis, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Matthias Oelze
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Franziska Bollmann
- Pharmacology Department, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Hartmut Kleinert
- Pharmacology Department, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Christian Otto
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Tjebo Heeren
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Sebastian Steven
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Michael Hausding
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
- Center of Thrombosis and Hemostasis, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Maike Knorr
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Andrea Pautz
- Pharmacology Department, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Kurt Reifenberg
- Central Laboratory Animal Facility, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Eberhard Schulz
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Tommaso Gori
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Philip Wenzel
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
- Center of Thrombosis and Hemostasis, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Thomas Münzel
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Andreas Daiber
- 2nd Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
- Corresponding author: Andreas Daiber,
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104
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Teng RJ, Du J, Xu H, Bakhutashvili I, Eis A, Shi Y, Pritchard KA, Konduri GG. Sepiapterin improves angiogenesis of pulmonary artery endothelial cells with in utero pulmonary hypertension by recoupling endothelial nitric oxide synthase. Am J Physiol Lung Cell Mol Physiol 2011; 301:L334-45. [PMID: 21622842 PMCID: PMC3174740 DOI: 10.1152/ajplung.00316.2010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 05/23/2011] [Indexed: 02/07/2023] Open
Abstract
Persistent pulmonary hypertension of the newborn (PPHN) is associated with decreased blood vessel density that contributes to increased pulmonary vascular resistance. Previous studies showed that uncoupled endothelial nitric oxide (NO) synthase (eNOS) activity and increased NADPH oxidase activity resulted in marked decreases in NO bioavailability and impaired angiogenesis in PPHN. In the present study, we hypothesize that loss of tetrahydrobiopterin (BH4), a critical cofactor for eNOS, induces uncoupled eNOS activity and impairs angiogenesis in PPHN. Pulmonary artery endothelial cells (PAEC) isolated from fetal lambs with PPHN (HTFL-PAEC) or control lambs (NFL-PAEC) were used to investigate the cellular mechanisms impairing angiogenesis in PPHN. Cellular mechanisms were examined with respect to BH4 levels, GTP-cyclohydrolase-1 (GCH-1) expression, eNOS dimer formation, and eNOS-heat shock protein 90 (hsp90) interactions under basal conditions and after sepiapterin (Sep) supplementation. Cellular levels of BH4, GCH-1 expression, and eNOS dimer formation were decreased in HTFL-PAEC compared with NFL-PAEC. Sep supplementation decreased apoptosis and increased in vitro angiogenesis in HTFL-PAEC and ex vivo pulmonary artery sprouting angiogenesis. Sep also increased cellular BH4 content, NO production, eNOS dimer formation, and eNOS-hsp90 association and decreased the superoxide formation in HTFL-PAEC. These data demonstrate that Sep improves NO production and angiogenic potential of HTFL-PAEC by recoupling eNOS activity. Increasing BH4 levels via Sep supplementation may be an important therapy for improving eNOS function and restoring angiogenesis in PPHN.
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Affiliation(s)
- Ru-Jeng Teng
- Division of Neonatology, Dept. of Pediatrics, Medical College of Wisconsin, Suite C410, Children Corporate Center, 999N 92nd St., Wauwatosa, WI 53226, USA.
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105
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Abstract
Cardioprotective strategies such as pre- and postconditioning result in a robust reduction in infarct size in young, healthy male animals. However, there are data suggesting that the protection is diminished in animals with comorbidities such as hypertension, hypercholesterolemia, and diabetes. It is important to understand at a mechanistic level the reasons for these differences. The effects of sex and diseases need to be considered in design of cardioprotective interventions in animal studies and clinical trials.
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Affiliation(s)
- Michael N Sack
- Center for Molecular Medicine, NHLBI, NIH, Bethesda, MD, USA
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106
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Jo H, Otani H, Jo F, Shimazu T, Okazaki T, Yoshioka K, Fujita M, Kosaki A, Iwasaka T. Inhibition of nitric oxide synthase uncoupling by sepiapterin improves left ventricular function in streptozotocin-induced diabetic mice. Clin Exp Pharmacol Physiol 2011; 38:485-93. [PMID: 21554376 DOI: 10.1111/j.1440-1681.2011.05535.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Uncoupling of nitric oxide synthase (NOS) has been implicated in the pathogenesis of left ventricular (LV) dysfunction in diabetes mellitus. In the present study, we investigated the role of NOS uncoupling in oxidative/nitrosative stress and LV dysfunction in the diabetic mouse heart. 2. Diabetes was induced in wild-type (WT), endothelial (e) NOS knockout (eNOS(-/-)), inducible (i) NOS knockout (iNOS(-/-)) and neuronal (n) NOS knockout (nNOS(-/-)) mice by streptozotocin (STZ) treatment. 3. In the diabetic heart, iNOS, but not eNOS or nNOS, expression was increased. Levels of malondialdehyde (MDA), 4-hydroxy-noneal (HNE) and nitrotyrosine (NT), as markers of oxidative/nitrosative stress, were increased in the diabetic mouse heart, but the increase in oxidative/nitrosative stress was significantly repressed in the iNOS(-/-) diabetic mouse heart. Levels of nitrite and nitrate (NO(x)), as an index of nitric oxide, bioavailability were significantly decreased in the iNOS(-/-) diabetic mouse heart. 4. Oral administration of sepiapterin (10 mg/kg per day), a precursor of tetrahydrobiopterin (BH(4)), significantly increased BH(4) and the BH(4)/BH(2) ratio in diabetic mouse heart. Similarly, sepiapterin inhibited the formation of HNE, MDA and NT in diabetic hearts from all three genotypes, but the increase in NO(x) following sepiapterin treatment was significantly attenuated in the iNOS(-/-) diabetic mouse heart. Percentage fractional shortening (FS), evaluated by echocardiography, decreased significantly in all genotypes of diabetic mice. Sepiapterin significantly increased percentage FS in diabetic mice, except in iNOS(-/-) mice. 5. These results suggest that sepiapterin inhibits uncoupling of NOS and improves LV function presumably by increasing iNOS-derived nitric oxide in the diabetic heart.
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Affiliation(s)
- Hiromi Jo
- Second Department of Internal Medicine, Kansai Medical University, Moriguchi, Japan
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107
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Knorr M, Hausding M, Kröller-Schuhmacher S, Steven S, Oelze M, Heeren T, Scholz A, Gori T, Wenzel P, Schulz E, Daiber A, Münzel T. Nitroglycerin-induced endothelial dysfunction and tolerance involve adverse phosphorylation and S-Glutathionylation of endothelial nitric oxide synthase: beneficial effects of therapy with the AT1 receptor blocker telmisartan. Arterioscler Thromb Vasc Biol 2011; 31:2223-31. [PMID: 21757654 DOI: 10.1161/atvbaha.111.232058] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Continuous administration of nitroglycerin (GTN) causes tolerance and endothelial dysfunction by inducing reactive oxygen species (ROS) production from various enzymatic sources, such as mitochondria, NADPH oxidase, and an uncoupled endothelial nitric oxide synthase (eNOS). In the present study, we tested the effects of type 1 angiotensin (AT(1))-receptor blockade with telmisartan on GTN-induced endothelial dysfunction in particular on eNOS phosphorylation and S-glutathionylation sites and the eNOS cofactor synthesizing enzyme GTP-cyclohydrolase I. METHODS AND RESULTS Wistar rats were treated with telmisartan (2.7 or 8 mg/kg per day PO for 10 days) and with GTN (50 mg/kg per day SC for 3 days). Aortic eNOS phosphorylation and S-glutathionylation were assessed using antibodies against phospho-Thr495 and Ser1177 or protein-bound glutathione, which regulate eNOS activity and eNOS-dependent superoxide production (uncoupling). Expression of mitochondrial aldehyde dehydrogenase was determined by Western blotting. Formation of aortic and cardiac ROS was assessed by fluorescence, chemiluminescence, and 3-nitrotyrosine/malondialdehyde-positive protein content. Telmisartan prevented endothelial dysfunction and partially improved nitrate tolerance. Vascular, cardiac, mitochondrial, and white blood cell ROS formation were significantly increased by GTN treatment and inhibited by telmisartan. GTN-induced decrease in Ser1177, increase in Thr495 phosphorylation or S-glutathionylation of eNOS, and decrease in mitochondrial aldehyde dehydrogenase expression were normalized by telmisartan. CONCLUSIONS These data identify modification of eNOS phosphorylation as an important component of GTN-induced endothelial dysfunction. Via its pleiotropic "antioxidant" properties, telmisartan prevents, at least in part, GTN-induced oxidative stress, nitrate tolerance, and endothelial dysfunction.
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Affiliation(s)
- Maike Knorr
- Second Medical Clinic, Department of Cardiology, Medical Center of Johannes Gutenberg University, Mainz, Germany
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108
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Feng B, Zhang YQ, Mu J, Yuan FH, Ye ZL, Qi W, Guo YH, Zeng W, Luo ZF. Uraemic serum induces dysfunction of vascular endothelial cells: role of ubiquitin-proteasome pathway. Exp Physiol 2011; 96:801-15. [PMID: 21602294 DOI: 10.1113/expphysiol.2011.058149] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ubiquitin-proteasome pathway (UPP) has been indicated to contribute to dysfunction of endothelial cells (ECs). Nevertheless, the relationship between UPP and vascular complications of uraemia remains unknown. We aimed to determine whether the UPP is activated in vascular ECs when cultured with uraemic serum, and to examine the role of the UPP on dysfunction of ECs in uraemia. Rabbit aortic endothelial cells (RAECs) were cultured with normal serum or different concentrations of uraemic serum. The expression of the ubiquitin-activating enzyme (E1), an indicator of the UPP, was detected by real-time RT-PCR and Western blot; proteasome activity was determined by fluorescence spectrophotometry; and nuclear factor-κB (NF-κB) activity and expression, as well as tumour necrosis factor-α (TNF-α) expression, were also detected. We found that the expression of E1 and the activities of three kinds of proteasomes were increased significantly in RAECs after incubation with uraemic serum. Proliferation of RAECs was increased significantly by incubation with 3-15% uraemic serum but decreased markedly when incubated with uraemic serum above 15% (increased apoptosis). Incubation of RAECs with uraemic serum induced increased NF-B DNA-binding activity and nuclear translocation of NF-κB, decreased nitric oxide production and increased expression of TNF-α, which is the final effector of inflammatory activation of cells. All of these responses in RAECs were suppressed by the specific proteasome inhibitor, MG132. The inhibition of inflammatory responses by MG132 was further supported by a parallel experiment with pyrrolidine dithiocarbamate, a specific inhibitor of κNF-B. These findings suggest that the UPP was activated in RAECs by administration of uraemic serum, and played a pivotal role in the dysfunction of vascular ECs, such as inflammatory activation.
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Affiliation(s)
- Bing Feng
- Department of Nephrology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
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109
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Kashihara N, Haruna Y, Kondeti VK, Kanwar YS. Oxidative stress in diabetic nephropathy. Curr Med Chem 2011; 17:4256-69. [PMID: 20939814 DOI: 10.2174/092986710793348581] [Citation(s) in RCA: 331] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2010] [Accepted: 10/04/2010] [Indexed: 12/14/2022]
Abstract
Diabetic nephropathy is a leading cause of end-stage renal failure worldwide. Its morphologic characteristics include glomerular hypertrophy, basement membrane thickening, mesangial expansion, tubular atrophy, interstitial fibrosis and arteriolar thickening. All of these are part and parcel of microvascular complications of diabetes. A large body of evidence indicates that oxidative stress is the common denominator link for the major pathways involved in the development and progression of diabetic micro- as well as macro-vascular complications of diabetes. There are a number of macromolecules that have been implicated for increased generation of reactive oxygen species (ROS), such as, NAD(P)H oxidase, advanced glycation end products (AGE), defects in polyol pathway, uncoupled nitric oxide synthase (NOS) and mitochondrial respiratory chain via oxidative phosphorylation. Excess amounts of ROS modulate activation of protein kinase C, mitogen-activated protein kinases, and various cytokines and transcription factors which eventually cause increased expression of extracellular matrix (ECM) genes with progression to fibrosis and end stage renal disease. Activation of renin-angiotensin system (RAS) further worsens the renal injury induced by ROS in diabetic nephropathy. Buffering the generation of ROS may sound a promising therapeutic to ameliorate renal damage from diabetic nephropathy, however, various studies have demonstrated minimal reno-protection by these agents. Interruption in the RAS has yielded much better results in terms of reno-protection and progression of diabetic nephropathy. In this review various aspects of oxidative stress coupled with the damage induced by RAS are discussed with the anticipation to yield an impetus for designing new generation of specific antioxidants that are potentially more effective to reduce reno-vascular complications of diabetes.
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Affiliation(s)
- N Kashihara
- Department of Internal Medicine, Kawasaki Medical School, Kurashiki, Okayama, Japan
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110
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Liu J, Zhang H, Xiao Z, Wang F, Wang X, Wang Y. Combined 3D-QSAR, molecular docking and molecular dynamics study on derivatives of peptide epoxyketone and tyropeptin-boronic acid as inhibitors against the β5 subunit of human 20S proteasome. Int J Mol Sci 2011; 12:1807-35. [PMID: 21673924 PMCID: PMC3111635 DOI: 10.3390/ijms12031807] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 02/14/2011] [Accepted: 02/28/2011] [Indexed: 12/13/2022] Open
Abstract
An abnormal ubiquitin-proteasome is found in many human diseases, especially in cancer, and has received extensive attention as a promising therapeutic target in recent years. In this work, several in silico models have been built with two classes of proteasome inhibitors (PIs) by using 3D-QSAR, homology modeling, molecular docking and molecular dynamics (MD) simulations. The study resulted in two types of satisfactory 3D-QSAR models, i.e., the CoMFA model (Q(2) = 0.462, R(2) (pred) = 0.820) for epoxyketone inhibitors (EPK) and the CoMSIA model (Q(2) = 0.622, R(2) (pred) = 0.821) for tyropeptin-boronic acid derivatives (TBA). From the contour maps, some key structural factors responsible for the activity of these two series of PIs are revealed. For EPK inhibitors, the N-cap part should have higher electropositivity; a large substituent such as a benzene ring is favored at the C6-position. In terms of TBA inhibitors, hydrophobic substituents with a larger size anisole group are preferential at the C8-position; higher electropositive substituents like a naphthalene group at the C3-position can enhance the activity of the drug by providing hydrogen bond interaction with the protein target. Molecular docking disclosed that residues Thr60, Thr80, Gly106 and Ser189 play a pivotal role in maintaining the drug-target interactions, which are consistent with the contour maps. MD simulations further indicated that the binding modes of each conformation derived from docking is stable and in accord with the corresponding structure extracted from MD simulation overall. These results can offer useful theoretical references for designing more potent PIs.
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Affiliation(s)
- Jianling Liu
- College of Life Sciences, Northwest University, Xi’an, Shaanxi 710069, China
| | - Hong Zhang
- College of Life Sciences, Northwest University, Xi’an, Shaanxi 710069, China
| | - Zhengtao Xiao
- Center of Bioinformatics, Northwest A&F University, Yangling, Shaanxi 712100, China; E-Mail:
| | - Fangfang Wang
- College of Life Sciences, Northwest University, Xi’an, Shaanxi 710069, China
| | - Xia Wang
- School of Chemical Engineering, Dalian University of Technology, Dalian 116012, China
| | - Yonghua Wang
- Center of Bioinformatics, Northwest A&F University, Yangling, Shaanxi 712100, China; E-Mail:
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111
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Oelze M, Knorr M, Schuhmacher S, Heeren T, Otto C, Schulz E, Reifenberg K, Wenzel P, Münzel T, Daiber A. Vascular dysfunction in streptozotocin-induced experimental diabetes strictly depends on insulin deficiency. J Vasc Res 2011; 48:275-84. [PMID: 21273782 DOI: 10.1159/000320627] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 08/20/2010] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVE In previous studies we and others have shown that streptozotocin (STZ)-induced diabetes in rats is associated with vascular oxidative stress and dysfunction. In the present study, we sought to determine whether vascular dysfunction and oxidative stress strictly depend on insulin deficiency. METHODS The effects of insulin (2.5 U/day s.c., 2 weeks) therapy on vascular disorders in STZ-induced (60 mg/kg i.v., 8 weeks) diabetes mellitus (type I) were studied in Wistar rats. The contribution of NADPH oxidase to overall oxidative stress was investigated by in vivo (30 mg/kg/day s.c., 4 days) and in vitro treatment with apocynin. RESULTS Insulin therapy completely normalized blood glucose, body weight, vascular dysfunction and oxidative stress as well as increased cardiac reactive oxygen and nitrogen species formation in diabetic rats, although diabetes was already established for 6 weeks before insulin therapy was started for the last 2 weeks of the total treatment interval. Apocynin normalized cardiac NADPH oxidase activity, and L-NAME effects suggest a role for uncoupled endothelial nitric oxide synthase in diabetic vascular complications. CONCLUSIONS Our findings indicate that STZ-induced diabetes is a model of insulin-dependent diabetes (type 1) and that cardiovascular complications are probably not associated with systemic toxic side effects of STZ.
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Affiliation(s)
- Matthias Oelze
- Second Medical Clinic, Department of Cardiology, Medical Center of the Johannes Gutenberg University, Mainz, Germany
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112
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Nawa A, Fujita-Hamabe W, Kishioka S, Tokuyama S. Decreased Expression of Intestinal P-glycoprotein Increases the Analgesic Effects of Oral Morphine in a Streptozotocin-induced Diabetic Mouse Model. Drug Metab Pharmacokinet 2011; 26:584-91. [DOI: 10.2133/dmpk.dmpk-11-rg-051] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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113
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Zhang M, Song P, Xu J, Zou MH. Activation of NAD(P)H oxidases by thromboxane A2 receptor uncouples endothelial nitric oxide synthase. Arterioscler Thromb Vasc Biol 2011; 31:125-32. [PMID: 20947827 PMCID: PMC3005129 DOI: 10.1161/atvbaha.110.207712] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The thromboxane receptor (TPr) and multiple TPr ligands, including thromboxane A(2) (TxA(2)) and prostaglandin H(2), are elevated during vascular and atherothrombotic diseases. How TPr stimulation causes vascular injury remains poorly defined. This study was conducted to investigate the mechanism by which TPr stimulation leads to vascular injury. METHODS AND RESULTS Exposure of bovine aortic endothelial cells to either [1S-(1α,2β(5Z),3α(1E,3R),4α]-7-[3-(3-hydroxy-4-(d'-iodophenoxy)-1-butenyl)-7-oxabicyclo-[2.2.1] heptan-2-yl]-5'-heptenoic acid (IBOP) or U46619, 2 structurally related TxA(2) mimetics, for 24 hours markedly increased the release of superoxide anions (O(2)(·-)) and peroxynitrite (ONOO(-)) but reduced cyclic GMP, an index of nitric oxide bioactivity. IBOP also significantly suppressed activity of endothelial nitric oxide synthase (eNOS), increased enzyme-inactive eNOS monomers, and reduced levels of tetrahydrobiopterin, an essential eNOS cofactor. IBOP- and U46619-induced increases in O(2)(·-) were accompanied by the membrane translocation of the p67(phox) subunit of NAD(P)H oxidase. Pharmacological or genetic inhibition of either NAD(P)H oxidase or TPr abolished IBOP-induced O(2)(·-) formation. Furthermore, TPr activation significantly increased protein kinase C-ζ (PKC-ζ) in membrane fractions and PKC-ζ phosphorylation at Thr410. Consistently, PKC-ζ inhibition abolished TPr activation-induced membrane translocation of p67(phox) and O(2)(·-) production. Finally, exposure of isolated mouse aortae to IBOP markedly increased O(2)(·-) in wild-type but not in those from gp91(phox) knockout mice. CONCLUSIONS We conclude that TPr activation via PKC-ζ-mediated NAD(P)H oxidase activation increases both O(2)(·-) and ONOO(-), resulting in eNOS uncoupling in endothelial cells.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Animals
- Apoptosis/drug effects
- Biopterins/analogs & derivatives
- Biopterins/metabolism
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- Cattle
- Cell Survival/drug effects
- Cells, Cultured
- Cyclic GMP/metabolism
- Cytochrome P-450 Enzyme System/metabolism
- Endothelial Cells/drug effects
- Endothelial Cells/enzymology
- Endothelial Cells/pathology
- Enzyme Activation
- Enzyme Inhibitors/pharmacology
- Fatty Acids, Unsaturated/pharmacology
- Intramolecular Oxidoreductases/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- NADPH Oxidases/antagonists & inhibitors
- NADPH Oxidases/genetics
- NADPH Oxidases/metabolism
- Nitric Oxide/metabolism
- Nitric Oxide Synthase Type III/metabolism
- Oxidative Stress/drug effects
- Peroxynitrous Acid/metabolism
- Phosphoproteins/metabolism
- Phosphorylation
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/metabolism
- Protein Processing, Post-Translational
- Protein Transport
- RNA Interference
- Receptors, Immunologic/deficiency
- Receptors, Immunologic/genetics
- Receptors, Thromboxane A2, Prostaglandin H2/agonists
- Receptors, Thromboxane A2, Prostaglandin H2/metabolism
- Signal Transduction/drug effects
- Superoxides/metabolism
- Time Factors
- Tyrosine/analogs & derivatives
- Tyrosine/metabolism
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Affiliation(s)
- Miao Zhang
- Department of Biochemistry and Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK 73104, USA
| | - Ping Song
- Department of Biochemistry and Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK 73104, USA
| | - Jian Xu
- Department of Biochemistry and Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK 73104, USA
| | - Ming-Hui Zou
- Department of Biochemistry and Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK 73104, USA
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114
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Preventive effect of a proteasome inhibitor on the formation of accelerated atherosclerosis in rabbits with uremia. J Cardiovasc Pharmacol 2010; 55:129-38. [PMID: 19935080 DOI: 10.1097/fjc.0b013e3181c87f8e] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Inflammation plays a central role in the pathogenesis of atherosclerosis. This study investigated whether the proteasome inhibitor has the same preventive effect on the formation of accelerated atherosclerosis in rabbits with uremia compared with a NF-kappaB inhibitor. New Zealand white rabbits were subjected to five-sixths nephrectomy (chronic renal failure [CRF]) or to a sham operation. Rats in each group were randomly assigned into three subgroups (n = 24 in each group) and treated with repeated intramuscular injections of proteasome inhibitor MG132 or NF-kappaB inhibitor PDTC for a specified period. Compared with sham rabbits, CRF rabbits displayed typical atherosclerotic changes (endothelial cell damage, intimal thickens, and appearance of foam cells). CRF rabbits had significantly higher levels of proteasome activity, NF-kappaB mRNA, protein, and DNA binding activity as well as tumor necrosis factor-a and proliferative cell nuclear antigen protein expression in aortic wall cells. CRF rabbits also showed lower levels of IkappaBalpha. Compared with CRF rabbits, CRF rabbits treatment with proteasome inhibitor MG132 showed restoration of IkappaBalpha mRNA and protein expression and decreased NF-kappaB DNA binding activity and tumor necrosis factor-a expression. Treatment with either proteasome inhibitor MG132 or NF-kappaB inhibitor PDTC could reverse these pathologic changes in the aortic wall cells of CRF rabbits. A comparison between the inhibitory effects of the two treatments revealed no statistical difference. These results suggest that ubiquitin-proteasome activation play a pivotal role in the pathogenesis of uremia-accelerated atherosclerosis. The ubiquitin-proteasome signaling pathway in aortic cells may therefore be an important target for preventing uremia-accelerated atherosclerosis.
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115
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Sun X, Fratz S, Sharma S, Hou Y, Rafikov R, Kumar S, Rehmani I, Tian J, Smith A, Schreiber C, Reiser J, Naumann S, Haag S, Hess J, Catravas JD, Patterson C, Fineman JR, Black SM. C-terminus of heat shock protein 70-interacting protein-dependent GTP cyclohydrolase I degradation in lambs with increased pulmonary blood flow. Am J Respir Cell Mol Biol 2010; 45:163-71. [PMID: 20870896 DOI: 10.1165/rcmb.2009-0467oc] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We showed that nitric oxide (NO) signaling is decreased in the pulmonary vasculature before the development of endothelial dysfunction in a lamb model of congenital heart disease and increased pulmonary blood flow (Shunt). The elucidation of the molecular mechanism by which this occurs was the purpose of this study. Here, we demonstrate that concentrations of the endogenous NO synthase (NOS) inhibitor, asymmetric dimethylarginine (ADMA), are elevated, whereas the NOS cofactor tetrahydrobiopterin (BH(4)) is decreased in Shunt lambs. Our previous studies demonstrated that ADMA decreases heat shock protein-90 (Hsp90) chaperone activity, whereas other studies suggest that guanosine-5'-triphosphate cyclohydrolase 1 (GCH1), the rate-limiting enzyme in the generation of BH(4), may be a client protein for Hsp90. Thus, we determined whether increases in ADMA could alter GCH1 protein and activity. Our data demonstrate that ADMA decreased GCH1 protein, but not mRNA concentrations, in pulmonary arterial endothelial cells (PAECs) because of the ubiquitination and proteasome-dependent degradation of GCH1. We also found that Hsp90-GCH1 interactions were reduced, whereas the association of GCH1 with Hsp70 and the C-terminus of Hsp70-interacting protein (CHIP) increased in ADMA-exposed PAECs. The overexpression of CHIP potentiated, whereas a CHIP U-box domain mutant attenuated, ADMA-induced GCH1 degradation and reductions in cellular BH(4) concentrations. We also found in vivo that Hsp90/GCH1 interactions are decreased, whereas GCH1-Hsp70 and GCH1-CHIP interactions and GCH1 ubiquitination are increased. Finally, we found that supplementation with l-arginine restored Hsp90-GCH1 interactions and increased both BH(4) and NO(x) concentrations in Shunt lambs. In conclusion, increased concentrations of ADMA can indirectly alter NO signaling through decreased cellular BH(4) concentrations, secondary to the disruption of Hsp90-GCH1 interactions and the CHIP-dependent proteasomal degradation of GCH1.
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Affiliation(s)
- Xutong Sun
- Program in Pulmonary Vascular Disease, Vascular Biology Center, Medical College of Georgia, 1459 Laney Walker Blvd., CB3211B, Augusta, GA 30912, USA
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116
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Liao YF, Zeng TS, Chen LL, Li YM, Yu F, Hu LJ, Yue L. Association of a functional polymorphism (C59038T) in GTP cyclohydrolase 1 gene and Type 2 diabetic macrovascular disease in the Chinese population. J Diabetes Complications 2010; 24:313-9. [PMID: 19515581 DOI: 10.1016/j.jdiacomp.2009.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 03/16/2009] [Accepted: 04/22/2009] [Indexed: 11/24/2022]
Abstract
Nitric oxide (NO) unavailability plays an important role in the progression of macrovascular diseases in Type 2 diabetes (T2DM). C59038T polymorphism in GTP cyclohydrolase 1 (GCH1) gene is a functional mutation involved in NO metabolism and cardiovascular risk in a multiethnic population. To clarify the relationship between C59038T polymorphism and macrovascular disease in T2DM, an association study was performed among 611 unrelated T2DM patients. C59038T polymorphism was detected by polymerase chain reaction (PCR) restriction fragment length polymorphism. The PCR products after digestion displayed three genotypes, including CC, CT, and TT. The prevalence of cardiovascular disease, cerebrovascular disease, and peripheral vascular disease was significantly higher in T2DM patients with TT genotype than those with CC or CT genotype (P<.001). Compared with CC or CC+CT genotype, T2DM patients with TT genotype had a significantly increased risk of macrovascular disease (P<.001, P=.001), with odds ratio for 4.717 [95% confidence interval: 3.056-7.370] and 4.082 (2.716-5.868), respectively. Subjects with TT genotype showed lower levels of plasma NOx (nitrite and nitrate), flow-mediated artery dilatation and activities of superoxide dismutase but higher levels of plasma malonaldehyde and intima-media thickness of carotid artery than those with CC or CT genotype (P<.05). This study demonstrated that in Chinese T2DM population, C59038T polymorphism was associated with an increased risk of macrovascular disease, which was likely due to its effects on NO metabolism, oxidative stress, and subsequently vascular dysfunction.
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Affiliation(s)
- Yun-fei Liao
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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117
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Abstract
Tetrahydrobiopterin (BH4) is a multifunctional cofactor of aromatic amino acid hydroxylases and nitric oxide synthase (NOS) as well as an intracellular antioxidant in animals. Through regulation of NOS activity BH4 plays a pivotal role not only in a variety of normal cellular functions but also in the pathogenesis of cardiovascular and neurodegenerative diseases, which develop under oxidative stress conditions. It appears that a balanced interplay between BH4 and NOS is crucial for cellular fate. If cellular BH4 homeostasis maintained by BH4 synthesis and regeneration fails to cope with increased oxidative stress, NOS is uncoupled to generate superoxide rather than NO and, in turn, exacerbates impaired BH4 homeostasis, thereby leading to cell death. The fundamental biochemical events involved in the BH4-NOS interplay are essentially the same, as revealed in mammalian endothelial, cardiac, and neuronal cells. This review summarizes information on the cellular BH4 homeostasis in mammals, focusing on its regulation under normal and oxidative stress conditions.
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118
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Castrén M, Nordberg P, Svensson L, Taccone F, Vincent JL, Desruelles D, Eichwede F, Mols P, Schwab T, Vergnion M, Storm C, Pesenti A, Pachl J, Guérisse F, Elste T, Roessler M, Fritz H, Durnez P, Busch HJ, Inderbitzen B, Barbut D. Intra-arrest transnasal evaporative cooling: a randomized, prehospital, multicenter study (PRINCE: Pre-ROSC IntraNasal Cooling Effectiveness). Circulation 2010; 122:729-36. [PMID: 20679548 DOI: 10.1161/circulationaha.109.931691] [Citation(s) in RCA: 271] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Transnasal evaporative cooling has sufficient heat transfer capacity for effective intra-arrest cooling and improves survival in swine. The aim of this study was to determine the safety, feasibility, and cooling efficacy of prehospital transnasal cooling in humans and to explore its effects on neurologically intact survival to hospital discharge. METHODS AND RESULTS Witnessed cardiac arrest patients with a treatment interval <or=20 minutes were randomized to intra-arrest cooling with a RhinoChill device (treatment group, n=96) versus standard care (control group, n=104). The final analysis included 93 versus 101 patients, respectively. Both groups were cooled after hospital arrival. The patients had similar demographics, initial rhythms, rates of bystander cardiopulmonary resuscitation, and intervals to cardiopulmonary resuscitation and arrival of advanced life support personnel. Eighteen device-related adverse events (1 periorbital emphysema, 3 epistaxis, 1 perioral bleed, and 13 nasal discolorations) were reported. Time to target temperature of 34 degrees C was shorter in the treatment group for both tympanic (102 versus 282 minutes, P=0.03) and core (155 versus 284 minutes, P=0.13) temperature. There were no significant differences in rates of return of spontaneous circulation between the groups (38% in treated subjects versus 43% in control subjects, P=0.48), in overall survival of those admitted alive (44% versus 31%, respectively, P=0.26), or in neurologically intact survival to discharge (Pittsburgh cerebral performance category scale 1 to 2, 34% versus 21%, P=0.21), although the study was not adequately powered to detect changes in these outcomes. CONCLUSIONS Prehospital intra-arrest transnasal cooling is safe and feasible and is associated with a significant improvement in the time intervals required to cool patients.
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Affiliation(s)
- Maaret Castrén
- Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden
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119
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Triggle CR, Ding H. A review of endothelial dysfunction in diabetes: a focus on the contribution of a dysfunctional eNOS. ACTA ACUST UNITED AC 2010; 4:102-15. [PMID: 20470995 DOI: 10.1016/j.jash.2010.02.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/25/2010] [Accepted: 02/04/2010] [Indexed: 12/31/2022]
Abstract
Although the etiology of vascular dysfunction in diabetes has been extensively investigated in both humans as well as animal models of human diabetes, the relative importance of the cellular pathways involved is still not fully understood. In this review, we focus on reviewing the literature that provides insights into how an acute exposure to hyperglycemia results in a dysregulation of endothelial nitric oxide synthase function, the subsequent downstream effects of endothelial nitric oxide synthase dysregulation, and the development of endothelial dysfunction.
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Affiliation(s)
- Chris R Triggle
- Department of Medical Education, Weill Cornell Medical College in Qatar, Education City, Doha, Qatar.
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120
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Kim HK, Ha SH, Han J. Potential therapeutic applications of tetrahydrobiopterin: from inherited hyperphenylalaninemia to mitochondrial diseases. Ann N Y Acad Sci 2010; 1201:177-82. [PMID: 20649554 DOI: 10.1111/j.1749-6632.2010.05623.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Tetrahydrobiopterin (BH(4)) is an essential enzymatic cofactor in the formation of key neurotransmitters and nitric oxide (NO). It also has a cellular protective role as an antioxidant and scavenger of reactive nitrogen or oxygen species. Inherited hyperphenylalaninemia, which is caused by mutations in converting enzymes responsible for BH(4) synthesis, was the first reported disease implicating BH(4). Oxidative stress can also cause decreased BH(4) levels, leading to uncoupling of BH(4)-nitric oxide synthase (NOS) and diminished NO, further aggravating numerous pathologies. BH(4) deficiency is found in cardiovascular, neurodegenerative, and metabolic diseases and is also involved in aging and mitochondrial dysfunction. BH(4) supplementation successfully prevents the development or progression of these diseases and thus has valuable clinical potential.
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Affiliation(s)
- Hyoung K Kim
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, Cardiovascular and Metabolic Disease Center, FIRST Mitochondrial Research Group, Inje University, Busan, Korea
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121
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Ding H, Triggle CR. Endothelial dysfunction in diabetes: multiple targets for treatment. Pflugers Arch 2010; 459:977-94. [PMID: 20238124 DOI: 10.1007/s00424-010-0807-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 02/13/2010] [Accepted: 02/16/2010] [Indexed: 12/20/2022]
Abstract
Robert Furchgott's discovery of the obligatory role that the endothelium plays in the regulation of vascular tone has proved to be a major advance in terms of our understanding of the cellular basis of diabetic vascular disease. Endothelial dysfunction, as defined by a reduction in the vasodilatation response to an endothelium-dependent vasodilator (such as acetylcholine) or to flow-mediated vasodilatation, is an early indicator for the development of the micro- and macroangipathy that is associated with diabetes. In diabetes, hyperglycaemia plays a key role in the initiation and development of endothelial dysfunction; however, the cellular mechanisms involved as well as the importance of dyslipidaemia and co-morbidities such as hypertension and obesity remain incompletely understood. In this review, we discuss the mechanisms whereby hyperglycaemia, oxidative stress and dyslipidaemia can alter endothelial function and highlight their effects on endothelial nitric oxide synthase (eNOS), the endothelium-dependent hyperpolarising factor (EDHF) pathway(s), as well as on the role of endothelium-derived contracting factors (EDCFs) and adipocyte-derived vasoactive factors such as adipose-derived relaxing factor (ADRF).
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Affiliation(s)
- Hong Ding
- Department of Pharmacology & Medical Education, Weill Cornell Medical College in Qatar, P.O. Box 24144, Education City, Doha, Qatar
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122
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Gangula PRR, Mukhopadhyay S, Ravella K, Cai S, Channon KM, Garfield RE, Pasricha PJ. Tetrahydrobiopterin (BH4), a cofactor for nNOS, restores gastric emptying and nNOS expression in female diabetic rats. Am J Physiol Gastrointest Liver Physiol 2010; 298:G692-9. [PMID: 20185690 PMCID: PMC2867432 DOI: 10.1152/ajpgi.00450.2009] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 02/18/2010] [Indexed: 01/31/2023]
Abstract
Gastroparesis is a debilitating disease predominantly affecting young women. Recently, dysregulation of neuronal nitric oxide synthase (nNOS) in myenteric plexus neurons has been implicated for delayed solid gastric emptying/gastroparesis in diabetic patients. In this study, we have explored the role of tetrahydrobiopterin (BH4), a major cofactor for nNOS activity and NO synthesis in diabetic gastroparesis. Diabetes was induced with single injection of streptozotocin (55 mg/kg body wt, ip) in female rats, with experiments performed on week 3 or 9 following induction, with or without 3-wk BH4 supplementation. Gastric pyloric BH4 levels were significantly decreased in diabetic female rats compared with control (18.6 +/- 1.45 vs. 31.0 +/- 2.31 pmol/mg protein). In vitro studies showed that 2,4-diamino-6-hydroxypyrimidine (DAHP), an inhibitor of BH4 synthesis, significantly decreased gastric NO release and nitrergic relaxation. Three-week dietary supplementation of BH4 either from day 1 or week 6 significantly attenuated diabetes-induced delayed gastric emptying for solids (3 wk: BH4, 67 +/- 6.7 vs. diabetic, 36.05 +/- 7.09; 9 wk: BH4, 57 +/- 8.45 vs. diabetic, 33 +/- 9.91) and diabetes-induced reduction in pyloric nNOS-alpha protein expression in female rats. Supplementation of BH4 significantly restored gastric nNOS-alpha dimerization in 9-wk-old diabetic female rats. In addition, BH4 treatment reversed (17.23 +/- 5.81 vs. 42.0 +/- 2.70 mmHg x s) the diabetes-induced changes in intragastric pressures (IGP) and gastric pyloric nitrergic relaxation (-0.62 +/- 0.01 vs. -0.22 +/- 0.07). BH4 deficiency plays a critical role in diabetes-induced alterations including delayed solid gastric emptying, increased IGP, reduced pyloric nitrergic relaxation, and nNOS-alpha expression in female rats. Supplementation of BH4 accelerates gastric emptying by restoring nitrergic system in diabetic female rats. Therefore, BH4 supplementation is a potential therapeutic option for female patients of diabetic gastroparesis.
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Affiliation(s)
- Pandu R R Gangula
- Department of Obstetrics and Gynecology, Center for Women's Health Research, Meharry Medical College, Nashville, Tennessee 37208, USA.
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123
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Queisser MA, Yao D, Geisler S, Hammes HP, Lochnit G, Schleicher ED, Brownlee M, Preissner KT. Hyperglycemia impairs proteasome function by methylglyoxal. Diabetes 2010; 59:670-8. [PMID: 20009088 PMCID: PMC2828656 DOI: 10.2337/db08-1565] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE The ubiquitin-proteasome system is the main degradation machinery for intracellularly altered proteins. Hyperglycemia has been shown to increase intracellular levels of the reactive dicarbonyl methylglyoxal (MGO) in cells damaged by diabetes, resulting in modification of proteins and alterations of their function. In this study, the influence of MGO-derived advanced glycation end product (AGE) formation on the activity of the proteasome was investigated in vitro and in vivo. RESEARCH DESIGN AND METHODS MGO-derived AGE modification of proteasome subunits was analyzed by mass spectrometry, immunoprecipitation, and Western blots. Proteasome activity was analyzed using proteasome-specific fluorogenic substrates. Experimental models included bovine retinal endothelial cells, diabetic Ins2(Akita) mice, glyoxalase 1 (GLO1) knockdown mice, and streptozotocin (STZ)-injected diabetic mice. RESULTS In vitro incubation with MGO caused adduct formation on several 20S proteasomal subunit proteins. In cultured endothelial cells, the expression level of the catalytic 20S proteasome subunit was not altered but proteasomal chymotrypsin-like activity was significantly reduced. In contrast, levels of regulatory 19S proteasomal proteins were decreased. In diabetic Ins2(Akita), STZ diabetic, and nondiabetic and diabetic G101 knockdown mice, chymotrypsin-like activity was also reduced and MGO modification of the 20S-beta2 subunit was increased. CONCLUSIONS Hyperglycemia-induced formation of MGO covalently modifies the 20S proteasome, decreasing its activity in the diabetic kidney and reducing the polyubiquitin receptor 19S-S5a. The results indicate a new link between hyperglycemia and impairment of cell functions.
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Affiliation(s)
- Markus A. Queisser
- School of Medicine, Institute of Biochemistry, Justus-Liebig-University, Giessen, Germany
- Diabetes Center, Albert Einstein College of Medicine, New York, New York
| | - Dachun Yao
- Diabetes Center, Albert Einstein College of Medicine, New York, New York
| | - Sven Geisler
- School of Medicine, Institute of Biochemistry, Justus-Liebig-University, Giessen, Germany
| | - Hans-Peter Hammes
- Department of Endocrinology, University of Heidelberg, Mannheim, Germany
| | - Günter Lochnit
- School of Medicine, Institute of Biochemistry, Justus-Liebig-University, Giessen, Germany
| | - Erwin D. Schleicher
- Department of Medicine IV, Eberhard-Karls-University, Tübingen, Germany
- Department of Neurology, Eberhard-Karls-University, Tübingen, Germany
| | - Michael Brownlee
- Diabetes Center, Albert Einstein College of Medicine, New York, New York
| | - Klaus T. Preissner
- School of Medicine, Institute of Biochemistry, Justus-Liebig-University, Giessen, Germany
- Corresponding author: Klaus T. Preissner,
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124
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Daiber A. Redox signaling (cross-talk) from and to mitochondria involves mitochondrial pores and reactive oxygen species. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:897-906. [PMID: 20122895 DOI: 10.1016/j.bbabio.2010.01.032] [Citation(s) in RCA: 273] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 01/15/2010] [Accepted: 01/26/2010] [Indexed: 12/13/2022]
Abstract
This review highlights the important role of redox signaling between mitochondria and NADPH oxidases. Besides the definition and general importance of redox signaling, the cross-talk between mitochondrial and Nox-derived reactive oxygen species (ROS) is discussed on the basis of 4 different examples. In the first model, angiotensin-II is discussed as a trigger for NADPH oxidase activation with subsequent ROS-dependent opening of mitochondrial ATP-sensitive potassium channels leading to depolarization of mitochondrial membrane potential followed by mitochondrial ROS formation and respiratory dysfunction. This concept was supported by observations that ethidium bromide-induced mitochondrial damage suppressed angiotensin-II-dependent increase in Nox1 and oxidative stress. In another example hypoxia was used as a stimulator of mitochondrial ROS formation and by using pharmacological and genetic inhibitors, a role of mitochondrial ROS for the induction of NADPH oxidase via PKCvarepsilon was demonstrated. The third model was based on cell death by serum withdrawal that promotes the production of ROS in human 293T cells by stimulating both the mitochondria and Nox1. By superior molecular biological methods the authors showed that mitochondria were responsible for the fast onset of ROS formation followed by a slower but long-lasting oxidative stress condition based on the activation of an NADPH oxidase (Nox1) in response to the fast mitochondrial ROS formation. Finally, a cross-talk between mitochondria and NADPH oxidases (Nox2) was shown in nitroglycerin-induced tolerance involving the mitochondrial permeability transition pore and ATP-sensitive potassium channels. The use of these redox signaling pathways as pharmacological targets is briefly discussed.
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Affiliation(s)
- Andreas Daiber
- Universitätsmedizin der Johannes Gutenberg-Universität Mainz, II. Med. Klinik u. Poliklinik-Labor für Molekulare Kardiologie, Obere Zahlbacher Str. 63, 55101 Mainz, Germany.
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125
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Satoh M, Haruna Y, Fujimoto S, Sasaki T, Kashihara N. Telmisartan improves endothelial dysfunction and renal autoregulation in Dahl salt-sensitive rats. Hypertens Res 2010; 33:135-42. [PMID: 19927153 DOI: 10.1038/hr.2009.190] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hypertensive vascular disorders are characterized by endothelial dysfunction. Loss of renal autoregulation causes glomerular hypertension. However, the relationship between the autoregulatory response and glomerular damage has not been well examined. We examined the contributions of uncoupled endothelial nitric oxide synthase (eNOS) in hypertensive renal disease, and the relationship between the degree of autoregulation impairment and glomerular injury. We also investigated the effects of telmisartan on eNOS coupling and renal autoregulation. Male Dahl salt-sensitive hypertensive (DS) rats (14-week old) fed an 8% salt diet were used to examine endothelial dysfunction and impaired renal autoregulation caused by glomerular hypertension. Some DS rats were treated with telmisartan (3.0 mg kg(-1) day(-1)), an angiotensin receptor blocker, for 2 weeks. Increased superoxide production and decreased nitric oxide production, as detected by fluorescent indicator perfusion methods, were observed in the glomeruli and arterioles of hypertensive DS rats. Telmisartan improved the imbalance of superoxide and nitric oxide in the glomeruli and arterioles. Decreased serum tetrahydrobiopterin levels and coupled eNOS seen in the DS rat kidney were improved with telmisartan treatment. The endothelial relaxation reaction was impaired in DS rat aortic arteries. Autoregulatory capacity in response to step changes in perfusion pressure was also impaired in DS rat kidney. Treatment with telmisartan improved these abnormalities. Endothelial dysfunction in the glomeruli and impaired renal autoregulation, which may cause glomerular sclerosis, were observed in DS rat kidney. Telmisartan treatment improves these dysfunctions in hypertensive renal disease.
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Affiliation(s)
- Minoru Satoh
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, Kurashiki, Okayama, Japan.
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126
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McCarty MF, Barroso-Aranda J, Contreras F. High-dose folate and dietary purines promote scavenging of peroxynitrite-derived radicals – Clinical potential in inflammatory disorders. Med Hypotheses 2009; 73:824-34. [DOI: 10.1016/j.mehy.2008.09.058] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 09/12/2008] [Accepted: 09/18/2008] [Indexed: 01/02/2023]
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127
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Affiliation(s)
- Jian Xu
- Department of Medicine and Endocrinology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104, USA
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128
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Vásquez-Vivar J. Tetrahydrobiopterin, superoxide, and vascular dysfunction. Free Radic Biol Med 2009; 47:1108-19. [PMID: 19628033 PMCID: PMC2852262 DOI: 10.1016/j.freeradbiomed.2009.07.024] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 06/20/2009] [Accepted: 07/15/2009] [Indexed: 01/06/2023]
Abstract
(6R)-5,6,7,8-Tetrahydrobiopterin (BH(4)) is an endogenously produced pterin that is found widely distributed in mammalian tissues. BH(4) works as a cofactor of aromatic amino acid hydroxylases and nitric oxide synthases. In the vasculature a deficit of BH(4) is implicated in the mechanisms of several diseases including atherosclerosis, hypertension, diabetic vascular disease, and vascular complications from cigarette smoking and environmental pollution. These ill-effects are connected to the ability of BH(4) to regulate reactive oxygen species levels in the endothelium. The possibility of using BH(4) as a therapeutical agent in cardiovascular medicine is becoming more compelling and many biochemical and physiological aspects involved in this application are currently under investigation. This review summarizes our current understanding of BH(4) reactivity and some aspects of cellular production and regulation.
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Affiliation(s)
- Jeannette Vásquez-Vivar
- Department of Biophysics, Free Radical Research Center, Redox Biology Program, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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129
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Herrmann J, Lerman LO, Lerman A. On to the road to degradation: atherosclerosis and the proteasome. Cardiovasc Res 2009; 85:291-302. [PMID: 19815565 DOI: 10.1093/cvr/cvp333] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Protein metabolism is a central element of every living cell. The ubiquitin-proteasome system (UPS) is an integral part of the protein metabolism machinery mediating post-transcriptional processing and degradation of the majority of intracellular proteins. Over the past few years, remarkable progress has been made in our understanding of the role of the UPS in vascular biology and pathobiology, particularly atherosclerosis. This review reflects on the recent developments from the effects on endothelial cells and the initial stage of atherosclerosis to the effects on vascular smooth muscle and the progression stage of atherosclerosis and finally to the effects on cell viability and the complication stage of atherosclerosis. It will conclude with the integration of the available information in a synoptic view of the involvement of the UPS in atherosclerosis.
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Affiliation(s)
- Joerg Herrmann
- Department of Internal Medicine, Division of Cardiovascular Diseases, Mayo Clinic Rochester, 200 First Street SW, Rochester, MN 55905, USA
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130
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131
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Xu J, Wang S, Wu Y, Song P, Zou MH. Tyrosine nitration of PA700 activates the 26S proteasome to induce endothelial dysfunction in mice with angiotensin II-induced hypertension. Hypertension 2009; 54:625-32. [PMID: 19597039 PMCID: PMC2910588 DOI: 10.1161/hypertensionaha.109.133736] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The ubiquitin-proteasome system has been implicated in oxidative stress-induced endothelial dysfunction in cardiovascular diseases. However, the mechanism by which oxidative stress alters the ubiquitin-proteasome system is poorly defined. The present study was conducted to determine whether oxidative modifications of PA700, a 26S proteasome regulatory subunit, contributes to angiotensin II (Ang II)-induced endothelial dysfunction. Exposure of human umbilical vein endothelial cells to low concentrations of Ang II, but not vehicle, for 6 hours significantly decreased the levels of tetrahydro-l-biopterin (BH4), an essential cofactor of endothelial NO synthase, which was accompanied by a decrease in GTP cyclohydrolase I, the rate-limiting enzyme for de novo BH4 synthesis. In addition, Ang II increased both tyrosine nitration of PA700 and the 26S proteasome activity, which were paralleled by increased coimmunoprecipitation of PA700 and the 20S proteasome. Genetic inhibition of NAD(P)H oxidase or administration of uric acid (a peroxynitrite scavenger) or N(G)-nitro-l-arginine methyl ester (nonselective NO synthase inhibitor) significantly attenuated Ang II-induced PA700 nitration, 26S proteasome activation, and reduction of GTP cyclohydrolase I and BH4. Finally, Ang II infusion in mice decreased the levels of both BH4 and GTP cyclohydrolase I and impaired endothelial-dependent relaxation in isolated aortas, and all of these effects were prevented by the administration of MG132, a potent inhibitor for 26S proteasome. We conclude that Ang II increases tyrosine nitration of PA700 resulting in accelerated GTP cyclohydrolase I degradation, BH4 deficiency, and consequent endothelial dysfunction in hypertension.
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Affiliation(s)
- Jian Xu
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, 941 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA.
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132
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Yang XQ, Chen AF. High-cholesterol diet augments endothelial dysfunction via elevated oxidative stress and reduced tetrahydrobiopterin in Ins2(Akita) mice, an autosomal dominant mutant type 1 diabetic model. Clin Exp Pharmacol Physiol 2009; 36:764-9. [PMID: 19207718 DOI: 10.1111/j.1440-1681.2009.05145.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Oxidative stress contributes to endothelial dysfunction and atherogenesis in diabetes. The present study tested the hypothesis that a high-cholesterol diet accelerates endothelial dysfunction in Ins2(Akita) mice, a Type 1 diabetic model with a spontaneous autosomal preproinsulin gene (Ins2 gene) mutation, through further increase of superoxide production. 2. The Ins2(Akita) diabetic mice were fed a high-cholesterol diet (1.25% cholesterol) for 4 months. Some Ins2(Akita) mice were also treated for 4 months with the selective NADPH oxidase inhibitor apocynin (4 mg/kg per day in drinking water). Oxidative stress markers, tetrahydrobiopterin (BH4) levels, GTP cyclohydrolase I activity and endothelial function were determined in serum or arteries afterwards. 3. Serum lipid peroxidation and arterial superoxide levels were increased, whereas arterial BH(4) levels and GTP cyclohydrolase I activity were decreased, in Ins2(Akita) mice on a high-cholesterol diet, resulting in impaired endothelium-dependent nitric oxide-mediated relaxation in response to acetylcholine. 4. In vivo treatment with apocynin not only blunted serum lipid peroxidation and arterial superoxide levels, but also increased BH4 levels and GTP cyclohydrolase I activity, resulting in improved endothelium-dependent relaxation. 5. These results suggest that NADPH oxidase may play a potential role in oxidative stress-induced arterial BH4 and GTP cyclohydrolase I deficiency, resulting in endothelial dysfunction in Ins2(Akita) Type 1 diabetic mice fed a high-cholesterol diet.
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MESH Headings
- Acetophenones/pharmacology
- Animals
- Biopterins/analogs & derivatives
- Biopterins/metabolism
- Cholesterol, Dietary/administration & dosage
- Cholesterol, Dietary/adverse effects
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/physiopathology
- Diabetes Mellitus, Type 1/etiology
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/physiopathology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiopathology
- Enzyme Inhibitors/pharmacology
- Genes, Dominant
- Insulin/genetics
- Lipid Peroxides/blood
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Mutation
- NADPH Oxidases/antagonists & inhibitors
- Oxidative Stress/drug effects
- Protein Precursors/genetics
- Superoxides/blood
- Vasodilation/drug effects
- Vasodilation/physiology
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Affiliation(s)
- Xiang-Qun Yang
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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133
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Wang S, Xu J, Song P, Viollet B, Zou MH. In vivo activation of AMP-activated protein kinase attenuates diabetes-enhanced degradation of GTP cyclohydrolase I. Diabetes 2009; 58:1893-901. [PMID: 19528375 PMCID: PMC2712774 DOI: 10.2337/db09-0267] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Accepted: 05/15/2009] [Indexed: 01/05/2023]
Abstract
OBJECTIVE The activation of AMP-activated protein kinase (AMPK) has been reported to improve endothelial function. However, the targets of AMPK in endothelial cells remain poorly defined. The aim of this study was to test whether AMPK suppresses the degradation of GTP-cyclohydrolase (GTPCH I), a key event in vascular endothelial dysfunction in diabetes. RESEARCH DESIGN AND METHODS Both human umbilical vein endothelial cells and aortas isolated from streptozotocin-injected diabetic mice were assayed for phospho-AMPK (Thr172), GTPCH I, tetrahydrobiopterin (BH4), and endothelial functions. RESULTS Oral administration of metformin (300 mg x kg(-1) . day(-1), 4 weeks) in streptozotocin-injected mice significantly blunted the diabetes-induced reduction of AMPK phosphorylation at Thr172. Metformin treatment also normalized acetylcholine-induced endothelial relaxation and increased the levels of GTPCH I and BH4. The administration of AICAR, an AMPK activator, or adenoviral overexpression of a constitutively active mutant of AMPK abolished the high-glucose-induced (30 mmol/l) reduction of GTPCH I, biopeterins, and BH4 but had no effect on GTPCH I mRNA. Furthermore, AICAR or overexpression of AMPK inhibited the high-glucose-enhanced 26S proteasome activity. Consistently, inhibition of the proteasome by MG132 abolished high-glucose-induced reduction of GTPCH I in human umbilical vein endothelial cells. Further, aortas isolated from AMPKalpha2(-/-) mice, which exhibited elevated 26S proteasome activity, had reduced levels of GTPCH I and BH4. Finally, either administration of MG132 or supplementation of l-sepiapterin normalized the impaired endothelium-dependent relaxation in aortas isolated from AMPKalpha2(-/-) mice. CONCLUSIONS We conclude that AMPK activation normalizes vascular endothelial function by suppressing 26S proteasome-mediated GTPCH I degradation in diabetes.
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Affiliation(s)
- Shuangxi Wang
- Division of Endocrinology and Diabetes, Department of Medicine, Herald Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Jian Xu
- Division of Endocrinology and Diabetes, Department of Medicine, Herald Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Ping Song
- Division of Endocrinology and Diabetes, Department of Medicine, Herald Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Benoit Viollet
- Institut Cochin, Paris, France
- University Paris Descartes, CNRS (UMR 8104), Paris, France
- Inserm, U567, Paris, France
| | - Ming-Hui Zou
- Division of Endocrinology and Diabetes, Department of Medicine, Herald Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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134
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Identification of proteins interacting with GTP cyclohydrolase I. Biochem Biophys Res Commun 2009; 385:143-7. [PMID: 19442649 DOI: 10.1016/j.bbrc.2009.05.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Accepted: 05/07/2009] [Indexed: 01/08/2023]
Abstract
GTP cyclohydrolase I (GCH-1) is the rate-limiting enzyme in the biosynthesis of tetrahydrobiopterin, an essential cofactor for nitric oxide synthase and aromatic amino acid hydroxylase. To explore the interactome of GCH-1, we established a HEK 293 cell line stably expressing tetracycline-inducible FLAG-GCH-1. FLAG-GCH-1 and associated proteins were immunoprecipitated and analyzed by liquid chromatography/tandem mass spectrometry. Twenty-nine proteins, derived from different subcellular components such as cytosol, membranes, nucleus and mitochondria were identified to interact with GCH-1. Cell fractionation studies also showed that GCH-1 was present in the cytosol, membranes and nucleus. Gene ontology analysis revealed that GCH-1 interactome was involved in a variety of biological processes such as signal transduction, apoptosis, metabolism, transport and cell organization. To our knowledge, this study is the first to provide a comprehensive analysis of the GCH-1 interactome. Findings expand the number and diversity of proteins that are known to associate with GCH-1.
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135
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Wilcox CS, Pearlman A. Chemistry and antihypertensive effects of tempol and other nitroxides. Pharmacol Rev 2009; 60:418-69. [PMID: 19112152 DOI: 10.1124/pr.108.000240] [Citation(s) in RCA: 288] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nitroxides can undergo one- or two-electron reduction reactions to hydroxylamines or oxammonium cations, respectively, which themselves are interconvertible, thereby providing redox metabolic actions. 4-Hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (tempol) is the most extensively studied nitroxide. It is a cell membrane-permeable amphilite that dismutates superoxide catalytically, facilitates hydrogen peroxide metabolism by catalase-like actions, and limits formation of toxic hydroxyl radicals produced by Fenton reactions. It is broadly effective in detoxifying these reactive oxygen species in cell and animal studies. When administered intravenously to hypertensive rodent models, tempol caused rapid and reversible dose-dependent reductions in blood pressure in 22 of 26 studies. This was accompanied by vasodilation, increased nitric oxide activity, reduced sympathetic nervous system activity at central and peripheral sites, and enhanced potassium channel conductance in blood vessels and neurons. When administered orally or by infusion over days or weeks to hypertensive rodent models, it reduced blood pressure in 59 of 68 studies. This was accompanied by correction of salt sensitivity and endothelial dysfunction and reduced agonist-evoked oxidative stress and contractility of blood vessels, reduced renal vascular resistance, and increased renal tissue oxygen tension. Thus, tempol is broadly effective in reducing blood pressure, whether given by acute intravenous injection or by prolonged administration, in a wide range of rodent models of hypertension.
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Affiliation(s)
- Christopher S Wilcox
- Division of Nephrology and Hypertension, Kidney and Vascular Disorder Center, Georgetown University, Washington, DC 20007, USA.
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136
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Marfella R, Di Filippo C, Portoghese M, Siniscalchi M, Martis S, Ferraraccio F, Guastafierro S, Nicoletti G, Barbieri M, Coppola A, Rossi F, Paolisso G, D'Amico M. The ubiquitin-proteasome system contributes to the inflammatory injury in ischemic diabetic myocardium: the role of glycemic control. Cardiovasc Pathol 2009; 18:332-45. [PMID: 19144543 DOI: 10.1016/j.carpath.2008.09.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2008] [Revised: 08/30/2008] [Accepted: 09/30/2008] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Because the ubiquitin-proteasome pathway (UPS) is required for activation of nuclear factor kappa beta (NFkB), a transcription factor that regulates inflammatory genes, we evaluated the UPS activity, NFkB activation, and tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, in ischemic specimens of diabetic myocardium and relate them to the glycemic control (HbA(1c)), oxidative stress (nitrotyrosine, a modified amino acid produced by reactive O(2)), and cardiac outcome (echocardiographic parameters). Moreover, the role of UPS, NFkB, and TNF-alpha in the cardiac tissue injury of acute ischemia/reperfusion (I/R) was evaluated in streptozotocin (STZ)-hyperglycemic rats. Finally, this study aimed to elucidate whether an intervention on UPS with bortezomib, an inhibitor of UPS, may counteract the extensive myocardial infarction and increased inflammatory reaction into the hyperglycemic myocardium. METHODS Ventricular biopsy specimens from 16 nondiabetic and 18 type 2 diabetic patients presenting with unstable angina who underwent coronary artery bypass were collected during coronary bypass surgery. Ejection fraction (EF); myocardial performance index (MPI), which measures both systolic and diastolic function, immunostaining, and cardiac levels of nitrotyrosine; UPS activity; NFkB; and TNF-alpha were investigated in both ischemic human myocardium and heart tissue from STZ-hyperglycemic rats subject to a myocardial ischemia/reperfusion procedure. RESULTS We found that diabetic patients had higher MPI (P<.041) and reduced EF (P<.008) compared with nondiabetic patients. Diabetic specimens had higher nitrotyrosine, UPS activity, NFkB, and TNF-alpha levels compared with nondiabetic patients (P<.001). This was mirrored by consistently high levels of UPS and inflammatory markers in STZ-infarcted hearts, associated with high myocardial damage. In contrast, lesions from normoglycemic animals as well as from hyperglycemic rats treated with bortezomib showed low levels of ubiquitin-proteasome activity, inflammation, and myocardial damage (P<.01). CONCLUSIONS By contributing to the increased inflammation, the UPS overactivity may enhance the risk of complication during myocardial ischemia in diabetic patients.
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Affiliation(s)
- Raffaele Marfella
- Department of Geriatrics and Metabolic Diseases, Second University of Naples, Naples, Italy.
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137
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Yu X, Patterson E, Kem DC. Targeting proteasomes for cardioprotection. Curr Opin Pharmacol 2008; 9:167-72. [PMID: 19097937 DOI: 10.1016/j.coph.2008.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Accepted: 11/05/2008] [Indexed: 10/21/2022]
Abstract
The ubiquitin-proteasome system (UPS) plays a central role in intracellular protein degradation and regulates many cellular processes, including cell proliferation, inflammation, adaptation to stress, cell death, and the removal of damaged or misfolded proteins. Numerous studies have demonstrated that altered UPS function is involved in the pathogenesis of a wide range of cardiac diseases including hypertrophy and failure, myocardial ischemia, atherosclerosis, and diabetic cardiovascular disease. Impairment of proteasome function is a common feature of cardiac disease; however several studies have also demonstrated increased proteasome activity in models similar but not identical with those having decreased function. Recent studies have shown that use of proteasome inhibitors before or following production of the model of cardiac disease may confer cardioprotection under certain conditions.
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Affiliation(s)
- Xichun Yu
- Endocrinology/Harold Hamm Oklahoma Diabetes Center & Heart Rhythm Institute, University of Oklahoma Health Sciences Center, 1200 Everett Dr, Oklahoma City, OK 73104, United States.
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138
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Satoh M, Fujimoto S, Arakawa S, Yada T, Namikoshi T, Haruna Y, Horike H, Sasaki T, Kashihara N. Angiotensin II type 1 receptor blocker ameliorates uncoupled endothelial nitric oxide synthase in rats with experimental diabetic nephropathy. Nephrol Dial Transplant 2008; 23:3806-13. [PMID: 18596126 PMCID: PMC2639062 DOI: 10.1093/ndt/gfn357] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 06/02/2008] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Recent studies showed that angiotensin II type 1 receptor blocker (ARB) slows progression of chronic renal disease in patients with type 2 diabetes, regardless of changes in blood pressure. We showed that the imbalance of nitric oxide (NO) and reactive oxygen species (ROS) due to endothelial NO synthase (eNOS) uncoupling contributed to renal dysfunction in the diabetic nephropathy. The aim of this study was to determine the effects of ARB on uncoupled eNOS in rat diabetic nephropathy. METHODS Diabetes was induced in Sprague-Dawley rats with streptozotocin (65 mg/ kg body weight). After 6 weeks, rats were divided into saline (DM; n = 11) and ARB, losartan groups (DM+Los; n = 11). After 2-week treatment, glomerular ROS production was assessed by 2',7'-dichlorofluorescin diacetate (DCFH-DA)-derived chemiluminescence. Renal NO and ROS production were imaged by confocal laser microscopy after renal perfusion with DCFH-DA and diaminorhodamine-4M acetoxymethyl ester with L-arginine. The dimeric form of eNOS was measured by low-temperature sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Serum tetrahydrobiopterin (BH4) concentrations were determined by high-performance liquid chromatography. Protein and mRNA expression of GTP cyclohydrolase 1 (GTPCH1), key enzyme of BH4 synthesis, were examined. RESULTS Losartan attenuated glomerular ROS production in DM. Accelerated ROS production and diminished bioavailable NO caused by NOS uncoupling were noted in DM glomeruli. Losartan reversed the decreased GTPCH1 and decreased dimeric form of eNOS and glomerular NO production by increased BH4 bioavailability. CONCLUSIONS ARB improved the NOS uncoupling in diabetic nephropathy by increasing BH4 bioavailability.
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Affiliation(s)
- Minoru Satoh
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan.
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139
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Xie Z, Zhang J, Wu J, Viollet B, Zou MH. Upregulation of mitochondrial uncoupling protein-2 by the AMP-activated protein kinase in endothelial cells attenuates oxidative stress in diabetes. Diabetes 2008; 57:3222-30. [PMID: 18835932 PMCID: PMC2584127 DOI: 10.2337/db08-0610] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Recent evidence suggests that the AMP-activated protein kinase (AMPK) is an important therapeutic target for diabetes. The present study was conducted to determine how AMPK activation suppressed tyrosine nitration of prostacyclin synthase in diabetes. RESEARCH DESIGN AND METHODS Confluent human umbilical vein endothelial cells (HUVECs) or mice were treated with 5-amino-4-imidazole carboxamide riboside (AICAR) for the detection of AMPK phosphorylation and the expression of mitochondrial uncoupling protein (UCP)-2. RESULTS Exposure of HUVECs to high glucose (30 mmol/l) increased superoxide anions (O(2).(-)) and prostacyclin synthase nitration. In addition, overexpression of constitutively active AMPK (Ad-CA-AMPK) or the addition of AICAR reduced both O(2).(-) and prostacyclin synthase nitration caused by high glucose, whereas adenoviral overexpression of dominant-negative AMPK mutants (Ad-DN-AMPK) enhanced the latter effects of high glucose. Exposure of HUVECs to either AICAR or metformin caused AMPK-dependent upregulation of both UCP-2 mRNA and UCP-2 protein. Furthermore, overexpression of UCP-2 significantly ablated both O(2).(-) and prostacyclin synthase nitration triggered by high glucose. Furthermore, overexpression of Ad-CA-AMPK increased, whereas overexpression of Ad-DN-AMPK inhibited AICAR-induced phosphorylation of p38 kinase at Thr180/Tyr182. Inhibition of p38 kinase with SB239063, which had no effect on AICAR-induced AMPK-Thr172 phosphorylation, dose dependently suppressed AICAR-induced upregulation of UCP-2, suggesting that AMPK lies upstream of p38 kinase. Finally, AICAR markedly increased UCP-2 expression and reduced both O(2).(-) and prostacyclin synthase nitration in diabetic wild-type mice but not in their AMPKalpha2-deficient counterparts in vivo. CONCLUSIONS We conclude that AMPK activation increases UCP-2, resulting in the inhibition of both O(2).(-) and prostacyclin synthase nitration in diabetes.
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Affiliation(s)
- Zhonglin Xie
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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140
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Nathan C. Epidemic inflammation: pondering obesity. Mol Med 2008; 14:485-92. [PMID: 18431463 DOI: 10.2119/2008-00038.nathan] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2008] [Accepted: 04/08/2008] [Indexed: 12/18/2022] Open
Abstract
Over the past two decades, inflammation has been recognized as a major driver in the pathogenesis of several common diseases, including atherosclerosis, diabetes, cancer, and asthma. Over the same period, there has been a steep rise in the incidence of obesity, a major risk factor for these disorders. Inflammation of adipose tissue is now recognized to accompany obesity and contribute to its sequelae. Thus, whereas obesity is primarily a disorder of energy balance, it may be helpful to consider it also as a form of epidemic inflammation that predisposes to other forms of epidemic inflammation. It is a fundamental biologic challenge to understand how a positive energy balance and inflammation are linked. This work reviews evidence that reactive oxygen and nitrogen intermediates (ROI and RNI) help drive chronic inflammation in the obese. This is proposed to be a maladaptive instance of our evolved dependence on ROI and RNI for both homeostatic signaling and host defense. ROI and RNI are well suited for these seemingly contradictory dual functions by their metabolic origin, high diffusibility in water and lipid, atomic specificity, and large number of molecular targets. When we eat so much and work so little that we repeatedly generate reactive compounds at levels normally reserved for emergencies, we treat our own cells like invading microbes.
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Affiliation(s)
- Carl Nathan
- Department of Microbiology & Immunology, Weill Cornell Medical College, New York, NY, USA.
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141
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Wenzel P, Schulz E, Oelze M, Müller J, Schuhmacher S, Alhamdani MSS, Debrezion J, Hortmann M, Reifenberg K, Fleming I, Münzel T, Daiber A. AT1-receptor blockade by telmisartan upregulates GTP-cyclohydrolase I and protects eNOS in diabetic rats. Free Radic Biol Med 2008; 45:619-26. [PMID: 18539157 DOI: 10.1016/j.freeradbiomed.2008.05.009] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 04/30/2008] [Accepted: 05/09/2008] [Indexed: 12/22/2022]
Abstract
Several enzymatic sources of reactive oxygen species (ROS) were described as potential reasons of eNOS uncoupling in diabetes mellitus. In the present study, we investigated the effects of AT1-receptor blockade with chronic telmisartan (25 mg/kg/day, 6.5 weeks) therapy on expression of the BH4-synthesizing enzyme GTP-cyclohydrolase I (GCH-I), eNOS uncoupling, and endothelial dysfunction in streptozotocin (STZ, 60 mg/kg iv, 7 weeks)-induced diabetes mellitus (type I). Telmisartan therapy did not modify blood glucose and body weight. Aortas from diabetic animals had vascular dysfunction as revealed by isometric tension studies (acetylcholine and nitroglycerin potency). Vascular and cardiac ROS produced by NADPH oxidase, mitochondria, eNOS, and xanthine oxidase were increased in the diabetic group as was the expression of NADPH oxidase subunits at the protein level. The expression of GCH-I and the phosphorylation of eNOS at Ser1177 was decreased by STZ treatment. Therapy with telmisartan normalized these parameters. The present study demonstrates for the first time that AT1-receptor blockade by telmisartan prevents downregulation of the BH4 synthase GCH-I and thereby eNOS uncoupling in experimental diabetes. In addition, telmisartan inhibits activation of superoxide sources like NADPH oxidase, mitochondria, and xanthine oxidase. These effects may explain the beneficial effects of telmisartan on endothelial dysfunction in diabetes.
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Affiliation(s)
- Philip Wenzel
- 2nd Medical Clinic, Department of Cardiology, Johannes Gutenberg University, Mainz, Germany
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142
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Choi HC, Song P, Xie Z, Wu Y, Xu J, Zhang M, Dong Y, Wang S, Lau K, Zou MH. Reactive nitrogen species is required for the activation of the AMP-activated protein kinase by statin in vivo. J Biol Chem 2008; 283:20186-97. [PMID: 18474592 PMCID: PMC2459304 DOI: 10.1074/jbc.m803020200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 05/09/2008] [Indexed: 11/06/2022] Open
Abstract
The AMP-activated protein kinase (AMPK) is reported to mediate the beneficial effects of statin on the vascular functions, but the biochemical mechanisms are incompletely understood. The aim of the study was to determine how statin activates AMPK. Exposure of confluent bovine aortic endothelial cells to simvastatin (statin) dose-dependently increased phosphorylation of AMPK at Thr(172) and activities of AMPK, which was in parallel with increased detection of both LKB1 phosphorylation at Ser(428) and LKB1 nuclear export. Furthermore, statin treatment was shown to increase protein kinase C (PKC)-zeta activity and PKC-zeta phosphorylation at Thr(410)/Thr(403). Consistently, inhibition of PKC-zeta either by pharmacological or genetic manipulations abolished statin-enhanced LKB1 phosphorylation at Ser(428), blocked LKB1 nucleus export, and prevented the subsequent activation of AMPK. Similarly, in vivo transfection of PKC-zeta-specific small interfering RNA in C57BL/6J mice significantly attenuated statin-enhanced phosphorylation of AMPK-Thr(172), acetyl-CoA carboxylase (ACC)-Ser(79), and LKB1-Ser(428). In addition, statin significantly increased reactive oxygen species, whereas preincubation of mito-TEMPOL, a superoxide dismutase mimetic, abolished statin-enhanced phosphorylation of both AMPK-Thr(172) and ACC-Ser(79). Finally, in vivo administration of statin increased 3-nitrotyrosine and the phosphorylation of AMPK and ACC in C57BL/6J mice but not in mice deficient in endothelial nitric-oxide synthase. Taken together, our data suggest that AMPK activation by statin is peroxynitrite-mediated but PKC-zeta-dependent.
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Affiliation(s)
- Hyoung Chul Choi
- Sections of Endocrinology and Nephrology, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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143
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Dong Y, Wu Y, Wu M, Wang S, Zhang J, Xie Z, Xu J, Song P, Wilson K, Zhao Z, Lyons T, Zou MH. Activation of protease calpain by oxidized and glycated LDL increases the degradation of endothelial nitric oxide synthase. J Cell Mol Med 2008; 13:2899-910. [PMID: 18624772 PMCID: PMC2821526 DOI: 10.1111/j.1582-4934.2008.00416.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Oxidation and glycation of low-density lipoprotein (LDL) promote vascular injury in diabetes; however, the mechanisms underlying this effect remain poorly defined. The present study was conducted to determine the effects of ‘heavily oxidized’ glycated LDL (HOG-LDL) on endothelial nitric oxide synthase (eNOS) function. Exposure of bovine aortic endothelial cells with HOG-LDL reduced eNOS protein levels in a concentration- and time-dependent manner, without altering eNOS mRNA levels. Reduced eNOS protein levels were accompanied by an increase in intracellular Ca2+, augmented production of reactive oxygen species (ROS) and induction of Ca2+-dependent calpain activity. Neither eNOS reduction nor any of these other effects were observed in cells exposed to native LDL. Reduction of intracellular Ca2+ levels abolished eNOS reduction by HOG-LDL, as did pharmacological or genetic through calcium channel blockers or calcium chelator BAPTA or inhibition of NAD(P)H oxidase (with apocynin) or inhibition of calpain (calpain 1-specific siRNA). Consistent with these results, HOG-LDL impaired acetylcholine-induced endothelium-dependent vasorelaxation of isolated mouse aortas, and pharmacological inhibition of calpain prevented this effect. HOG-LDL may impair endothelial function by inducing calpain-mediated eNOS degradation in a ROS- and Ca2+-dependent manner.
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Affiliation(s)
- Yunzhou Dong
- Harold Hamm Oklahoma Diabetes Center, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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144
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Herrmann J, Soares SM, Lerman LO, Lerman A. Potential role of the ubiquitin-proteasome system in atherosclerosis: aspects of a protein quality disease. J Am Coll Cardiol 2008; 51:2003-10. [PMID: 18498952 DOI: 10.1016/j.jacc.2008.02.047] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 01/28/2008] [Accepted: 02/12/2008] [Indexed: 11/28/2022]
Abstract
Misfolded or damaged proteins are recognized intracellularly by protein quality mechanisms. These include chaperones and the ubiquitin-proteasome system, which aim at restoration of protein function and protein removal, respectively. A number of studies have outlined the functional significance of the ubiquitin-proteasome system for the heart and, as of recently, for the vascular system. This review summarizes these recent findings with a focus on atherosclerosis. In particular, this paper reflects on the viewpoint of atherosclerosis as a protein quality disease.
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Affiliation(s)
- Joerg Herrmann
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
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145
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Wenzel P, Daiber A, Oelze M, Brandt M, Closs E, Xu J, Thum T, Bauersachs J, Ertl G, Zou MH, Förstermann U, Müunzel T. Mechanisms underlying recoupling of eNOS by HMG-CoA reductase inhibition in a rat model of streptozotocin-induced diabetes mellitus. Atherosclerosis 2008; 198:65-76. [PMID: 18061195 PMCID: PMC2889614 DOI: 10.1016/j.atherosclerosis.2007.10.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 09/29/2007] [Accepted: 10/01/2007] [Indexed: 02/07/2023]
Abstract
OBJECTIVE HMG-CoA reductase inhibitors have been shown to upregulate GTP cyclohydrolase I (GTPCH-I), the key enzyme for tetrahydrobiopterin de novo synthesis and to normalize tetrahydrobiopterin levels in hyperglycemic endothelial cells. We sought to determine whether in vivo treatment with the HMG-CoA reductase inhibitor atorvastatin is able to upregulate the GTPCH-I, to recouple eNOS and to normalize endothelial dysfunction in an experimental model of diabetes mellitus. METHODS AND RESULTS In male Wistar rats, diabetes was induced by streptozotocin (STZ, 60 mg/kg). In STZ rats, atorvastatin feeding (20 mg/kg/d, 7 weeks), normalized vascular dysfunction as analyzed by isometric tension studies, levels of circulating endothelial progenitor cells (FACS-analysis), superoxide formation (assessed by lucigenin-enhanced chemiluminescence and dihydroethidium staining), vascular levels of the phosphorylated vasodilator-stimulated phosphoprotein (P-VASP), tyrosine nitration of the prostacyclin synthase, expression of GTPCH-I, dihydrofolate reductase and eNOS, translocation of regulatory NADPH oxidase subunits rac1, p47phox and p67phox (assessed by Western blot) and vascular tetrahydrobiopterin levels as measured by HPLC. Dihydroethidine staining revealed that the reduction of vascular superoxide was at least in part due to eNOS recoupling. CONCLUSION HMG-CoA reductase inhibition normalizes endothelial function and reduces oxidative stress in diabetes by inhibiting activation of the vascular NADPH oxidase and by preventing eNOS uncoupling due to an upregulation of the key enzyme of tetrahydrobiopterin synthesis, GTPCH-I.
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Affiliation(s)
- Philip Wenzel
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Andreas Daiber
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Matthias Oelze
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Moritz Brandt
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Ellen Closs
- Department of Pharmacology, Johannes-Gutenberg-University, Obere Zahlbacher Strasse 67, 55131 Mainz, Germany
| | - Jian Xu
- Department of Medicine and Endocrinology, University of Oklahoma Health Science Center, 941 Stanton L. Young Blvd., Oklahoma City, OK 73013, USA
| | - Thomas Thum
- Medical Clinic I, Department of Cardiology, Bavarian Julius-Maximilians-University Wurzburg Klinikstrasse 6-8, 97070 Würzburg, Germany
| | - Johann Bauersachs
- Medical Clinic I, Department of Cardiology, Bavarian Julius-Maximilians-University Wurzburg Klinikstrasse 6-8, 97070 Würzburg, Germany
| | - Georg Ertl
- Medical Clinic I, Department of Cardiology, Bavarian Julius-Maximilians-University Wurzburg Klinikstrasse 6-8, 97070 Würzburg, Germany
| | - Ming-Hui Zou
- Department of Medicine and Endocrinology, University of Oklahoma Health Science Center, 941 Stanton L. Young Blvd., Oklahoma City, OK 73013, USA
| | - Ulrich Förstermann
- Department of Pharmacology, Johannes-Gutenberg-University, Obere Zahlbacher Strasse 67, 55131 Mainz, Germany
| | - Thomas Müunzel
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
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146
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Marfella R, Di Filippo C, Portoghese M, Ferraraccio F, Crescenzi B, Siniscalchi M, Barbieri M, Bologna C, Rizzo MR, Rossi F, D'Amico M, Paolisso G. Proteasome activity as a target of hormone replacement therapy-dependent plaque stabilization in postmenopausal women. Hypertension 2008; 51:1135-41. [PMID: 18259030 DOI: 10.1161/hypertensionaha.107.105239] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The molecular mechanisms of the atheroprotective effect evoked by hormone replacement therapy in postmenopausal women is not well known. Recently, we have demonstrated enhanced activity of the ubiquitin-proteasome system in human atherosclerotic plaques and evidenced that it is associated with inflammatory-induced plaque rupture. Therefore, we hypothesized that hormone replacement therapy may exert the cardioprotective effects modulating the ubiquitin-proteasome activity. To investigate this possibility, this study examined the differences in inflammatory infiltration, as well as ubiquitin-proteasome activity, between asymptomatic carotid plaques of postmenopausal women with and without concomitant hormone replacement therapy. Plaques were obtained from 20 postmenopausal women treated with hormone replacement therapy (current users) and 32 nontreated women (never-users) enlisted to undergo carotid endarterectomy for extracranial high-grade (>70%) internal carotid artery stenosis. Plaques were analyzed for macrophages, T lymphocytes, human leukocyte antigen-DR+ cells, ubiquitin-proteasome system, nuclear factor kappaB, inhibitor of nuclear factor kappaBbeta, tumor necrosis factor-alpha, nitrotyrosine, matrix metalloproteinase-9, and collagen content (immunohistochemistry and ELISA). Compared with plaques from current users, plaques from never-users had more macrophages, T lymphocytes, and human leukocyte antigen-DR+ cells (P<0.001); more ubiquitin-proteasome activity, tumor necrosis factor-alpha, and nuclear factor kappaB (P<0.001); and more nitrotyrosine and matrix metalloproteinase-9 (P<0.001), along with a lesser collagen content and inhibitor of nuclear factor kappaBbeta levels (P<0.001). This study supports the hypothesis that hormone replacement therapy inhibits plaque ubiquitin-proteasome activity by decreasing oxidative stress generation in postmenopausal women. This effect, in turn, might contribute to plaque stabilization by inhibiting the activation of nuclear factor kappaB-dependent inflammation, responsible for plaque rupture.
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Affiliation(s)
- Raffaele Marfella
- Department of Geriatric and Metabolic Diseases, Second University Naples, Naples, Italy.
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147
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Zou MH, Wu Y. AMP-activated protein kinase activation as a strategy for protecting vascular endothelial function. Clin Exp Pharmacol Physiol 2007; 35:535-45. [PMID: 18177481 DOI: 10.1111/j.1440-1681.2007.04851.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
1. AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase involved in the regulation of cellular and organismal metabolism. AMPK has a heterotrimeric structure, consisting of a catalytic alpha-subunit and regulatory beta- and gamma-subunits, each of which has two or more isoforms that are differentially expressed in various tissues and that arise from distinct genes. The AMPK system acts as a sensor of cellular energy status that is conserved in all eukaryotic cells. In addition, AMPK is activated by physiological stimuli and oxidants. 2. The importance of AMPK in cardiovascular functions is best demonstrated by recent studies showing that widely used drugs, including statins, metformin and rosiglitazone, execute cardiovascular protective effects at least partly through the activation of AMPK. As a consequence, AMPK has been proposed as a candidate target for therapeutic intervention in the treatment of both Type 2 diabetes and metabolic syndrome owing to its central role in the regulation of energy balance; it may also have a role in weight control. 3. In the present brief review, we summarize the recent progress of AMPK signalling and regulation focusing on vascular endothelial cells. We further hypothesize that AMPK is a dual sensor for energy and redox status within a cell and AMPK may be a therapeutic target for protecting vascular endothelial function.
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Affiliation(s)
- Ming-Hui Zou
- Section of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA.
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148
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Marfella R, D' Amico M, Di Filippo C, Siniscalchi M, Sasso FC, Ferraraccio F, Rossi F, Paolisso G. The possible role of the ubiquitin proteasome system in the development of atherosclerosis in diabetes. Cardiovasc Diabetol 2007; 6:35. [PMID: 17971205 PMCID: PMC2169213 DOI: 10.1186/1475-2840-6-35] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 10/30/2007] [Indexed: 12/17/2022] Open
Abstract
We have reviewed the impact of the ubiquitin proteasome system (UPS) on atherosclerosis progression of diabetic patients. A puzzle of many pieces of evidence suggests that UPS, in addition to its role in the removal of damaged proteins, is involved in a number of biological processes including inflammation, proliferation and apoptosis, all of which constitute important characteristics of atherosclerosis. From what can be gathered from the very few studies on the UPS in diabetic cardiovascular diseases published so far, the system seems to be functionally active to a different extent in the initiation, progression, and complication stage of atherosclerosis in the diabetic people. Further evidence for this theory, however, has to be given, for instance by specifically targeted antagonism of the UPS. Nonetheless, this hypothesis may help us understand why diverse therapeutic interventions, which have in common the ability to reduce ubiquitin-proteasome activity, can impede or delay the onset of diabetes and cardiovascular diseases (CVD). People with type 2 diabetes are disproportionately affected by CVD, compared with those without diabetes [1]. The prevalence, incidence, and mortality from all forms of CVD (myocardial infarction, cerebro-vascular disease and congestive heart failure) are strikingly increased in persons with diabetes compared with those withoutdiabetes [2]. Furthermore, diabetic patients have not benefited by the advances in the management of obesity, dyslipidemia, and hypertension that have resulted in a decrease in mortality for coronary heart disease (CHD) patients without diabetes [3]. Nevertheless, these risk factors do not fully explain the excess risk for CHD associated with diabetes [4,5]. Thus, the determinants of progression of atherosclerosis in persons with diabetes must be elucidated. Beyond the major risk factors, several studies have demonstrated that such factors, strictly related to diabetes, as insulin-resistance, post-prandial hyperglycemia and chronic hyperglycemia play a role in the atherosclerotic process and may require intervention [6,7]. Moreover, it is important to recognize that these risk factors frequently "cluster" inindividual patients and possibly interact with each other, favouring the atherosclerosis progression toward plaque instability. Thus, a fundamental question is, "which is the common soil hypothesis that may unifying the burden of all these factors on atherosclerosis of diabetic patients? Because evidences suggest that insulin-resistance, diabetes and CHD share in common a deregulation of ubiquitin-proteasome system (UPS), the major pathway for nonlysosomal intracellular protein degradation in eucaryotic cells [8,9], in this review ubiquitin-proteasome deregulation is proposed as the common persistent pathogenic factor mediating the initial stage of the atherosclerosis as well as the progression to complicated plaque in diabetic patients.
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Affiliation(s)
- Raffaele Marfella
- Department of Geriatrics and Metabolic Diseases, Second University of Naples, Italy.
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