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Shraim BA, Moursi MO, Benter IF, Habib AM, Akhtar S. The Role of Epidermal Growth Factor Receptor Family of Receptor Tyrosine Kinases in Mediating Diabetes-Induced Cardiovascular Complications. Front Pharmacol 2021; 12:701390. [PMID: 34408653 PMCID: PMC8365470 DOI: 10.3389/fphar.2021.701390] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/14/2021] [Indexed: 12/15/2022] Open
Abstract
Diabetes mellitus is a major debilitating disease whose global incidence is progressively increasing with currently over 463 million adult sufferers and this figure will likely reach over 700 million by the year 2045. It is the complications of diabetes such as cardiovascular, renal, neuronal and ocular dysfunction that lead to increased patient morbidity and mortality. Of these, cardiovascular complications that can result in stroke and cardiomyopathies are 2- to 5-fold more likely in diabetes but the underlying mechanisms involved in their development are not fully understood. Emerging research suggests that members of the Epidermal Growth Factor Receptor (EGFR/ErbB/HER) family of tyrosine kinases can have a dual role in that they are beneficially required for normal development and physiological functioning of the cardiovascular system (CVS) as well as in salvage pathways following acute cardiac ischemia/reperfusion injury but their chronic dysregulation may also be intricately involved in mediating diabetes-induced cardiovascular pathologies. Here we review the evidence for EGFR/ErbB/HER receptors in mediating these dual roles in the CVS and also discuss their potential interplay with the Renin-Angiotensin-Aldosterone System heptapeptide, Angiotensin-(1-7), as well the arachidonic acid metabolite, 20-HETE (20-hydroxy-5, 8, 11, 14-eicosatetraenoic acid). A greater understanding of the multi-faceted roles of EGFR/ErbB/HER family of tyrosine kinases and their interplay with other key modulators of cardiovascular function could facilitate the development of novel therapeutic strategies for treating diabetes-induced cardiovascular complications.
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Affiliation(s)
- Bara A Shraim
- College of Medicine, QU Health, Qatar University, Doha, Qatar.,Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha, Qatar
| | - Moaz O Moursi
- College of Medicine, QU Health, Qatar University, Doha, Qatar.,Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha, Qatar
| | - Ibrahim F Benter
- Faculty of Medicine, Eastern Mediterranean University, Famagusta, North Cyprus
| | - Abdella M Habib
- College of Medicine, QU Health, Qatar University, Doha, Qatar.,Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha, Qatar
| | - Saghir Akhtar
- College of Medicine, QU Health, Qatar University, Doha, Qatar.,Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha, Qatar
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Oxidative Stress, Plant Natural Antioxidants, and Obesity. Int J Mol Sci 2021; 22:ijms22041786. [PMID: 33670130 PMCID: PMC7916866 DOI: 10.3390/ijms22041786] [Citation(s) in RCA: 149] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/07/2021] [Accepted: 02/08/2021] [Indexed: 02/07/2023] Open
Abstract
Oxidative stress is important in the pathophysiology of obesity, altering regulatory factors of mitochondrial activity, modifying the concentration of inflammation mediators associated with a large number and size of adipocytes, promoting lipogenesis, stimulating differentiation of preadipocytes to mature adipocytes, and regulating the energy balance in hypothalamic neurons that control appetite. This review discusses the participation of oxidative stress in obesity and the important groups of compounds found in plants with antioxidant properties, which include (a) polyphenols such as phenolic acids, stilbenes, flavonoids (flavonols, flavanols, anthocyanins, flavanones, flavones, flavanonols, and isoflavones), and curcuminoids (b) carotenoids, (c) capsaicinoids and casinoids, (d) isothiocyanates, (e) catechins, and (f) vitamins. Examples are analyzed, such as resveratrol, quercetin, curcumin, ferulic acid, phloretin, green tea, Hibiscus Sabdariffa, and garlic. The antioxidant activities of these compounds depend on their activities as reactive oxygen species (ROS) scavengers and on their capacity to prevent the activation of NF-κB (nuclear factor κ-light-chain-enhancer of activated B cells), and reduce the expression of target genes, including those participating in inflammation. We conclude that natural compounds have therapeutic potential for diseases mediated by oxidative stress, particularly obesity. Controlled and well-designed clinical trials are still necessary to better know the effects of these compounds.
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Liu Y, Wei J, Ma KT, Li CL, Mai YP, Qiu XX, Wei H, Hou N, Luo JD. Carvacrol protects against diabetes-induced hypercontractility in the aorta through activation of the PI3K/Akt pathway. Biomed Pharmacother 2020; 125:109825. [PMID: 32036208 DOI: 10.1016/j.biopha.2020.109825] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 12/10/2019] [Accepted: 12/18/2019] [Indexed: 11/16/2022] Open
Abstract
Vascular complications induced by diabetes constitute the principal cause of morbidity and mortality in diabetic patients. It has been reported that carvacrol (CAR) possesses a wide range of biological activities. The effects of CAR on diabetes-induced vasculopathy remain unknown. In this study, diabetic mice were created by the intraperitoneal injection of streptozotocin (STZ) in male C57BL/6 J mice to investigate whether CAR provided a protective effect against diabetes-induced vasculopathy and to investigate the underlying mechanisms. We found that CAR decreased blood glucose levels in diabetic mice. Moreover, CAR ameliorated diabetes-induced aortic morphological alterations, as evidenced by an increased thickness in the intima-media width and an increased number of vascular smooth muscle cells (VSMCs) layers. Further studies revealed that CAR inhibited hypercontractility in the aortas of diabetic mice and VSMCs in response to hyperglycemia, as evidenced by the relaxation of phenylephrine(PE)-induced vasoconstriction, the decreased expression of smooth muscle (SM)-α-actin, and the increased expression of Ki67 and proliferating cell nuclear antigen (PCNA). Furthermore, the PI3K/Akt signaling pathway was inhibited in the aortas of diabetic mice and VSMCs in response to hyperglycemia, while CAR treatment activated the PI3K/Akt signaling pathway. In conclusion, our results strongly suggest that CAR plays a protective role in diabetes-induced aortic hypercontractility, possibly by activating the PI3K/Akt signaling pathway. CAR is a potential drug for the treatment of diabetic vasculopathy.
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Affiliation(s)
- Yun Liu
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, PR China
| | - Jie Wei
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, PR China
| | - Kai-Ting Ma
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, PR China
| | - Cong-Lin Li
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, PR China
| | - Yun-Pei Mai
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, PR China
| | - Xiao-Xia Qiu
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, PR China
| | - Han Wei
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, PR China
| | - Ning Hou
- Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, PR China.
| | - Jian-Dong Luo
- Guangzhou Institute of Cardiovascular Disease, Guangzhou Key Laboratory of Cardiovascular Disease, and the Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, PR China.
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Watanabe S, Matsumoto T, Ando M, Adachi T, Kobayashi S, Iguchi M, Takeuchi M, Taguchi K, Kobayashi T. Multiple activation mechanisms of serotonin-mediated contraction in the carotid arteries obtained from spontaneously hypertensive rats. Pflugers Arch 2016; 468:1271-1282. [PMID: 27170312 DOI: 10.1007/s00424-016-1834-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 12/21/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) is an important endogenous substance that regulates the vascular tone, and the abnormal signaling of 5-HT has been observed in the arteries under several pathophysiological conditions such as diabetes and hypertension. However, signaling pathways of 5-HT-mediated vasocontraction in hypertension remain unclear. Therefore, we tested the hypothesis that 5-HT-mediated contraction and contributions of various kinases such as mitogen-activated protein kinases (MAPKs), phosphoinositide 3-kinase (PI3K), Rho kinase (ROCK), and 3-phosphoinositide-dependent kinase 1 (PDK1) to the contraction would be altered in the carotid arteries obtained from spontaneously hypertensive rats (SHR) compared to control Wistar Kyoto (WKY) rats. In the carotid arteries from SHR (vs. those from WKY), (1) the 5-HT-mediated contraction was increased, whereas the norepinephrine-mediated contraction was not; (2) 5-HT-mediated contractions were partly inhibited by each kinase (extracellular signal-regulated kinase 1/2 (ERK1/2), p38 MAPK, c-Jun N-terminal kinase (JNK), PI3K, ROCK, and PDK1) inhibitor; and (3) 5-HT-stimulated phosphorylation of ERK1/2, p38 MAPK, JNK, myosin phosphatase target subunit 1 (MYPT1), and PDK1 was increased. The expression of ROCK2 but not ROCK1 was increased in the carotid arteries from SHR compared to WKY. The expression of 5-HT2A receptor, a major receptor of 5-HT-mediated contraction in rat carotid artery, was similar in carotid arteries between the two groups. These results suggest that 5-HT-mediated contraction was utilized multiple signaling pathways such as ERK1/2, p38 MAPK, JNK, PI3K, ROCK, and PDK1. Although 5-HT-mediated contraction was increased in the carotid arteries obtained from SHR, further studies are necessary to clarify how each kinase may integrate in the vascular smooth muscles under hypertension.
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Affiliation(s)
- Shun Watanabe
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Makoto Ando
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Tsuyuki Adachi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Shota Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Maika Iguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Miki Takeuchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Kumiko Taguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan
| | - Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan.
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Han Y, Li X, Zhou S, Meng G, Xiao Y, Zhang W, Wang Z, Xie L, Liu Z, Lu H, Ji Y. 17ß-estradiol antagonizes the down-regulation of ERα/NOS-3 signaling in vascular endothelial dysfunction of female diabetic rats. PLoS One 2012; 7:e50402. [PMID: 23209733 PMCID: PMC3510182 DOI: 10.1371/journal.pone.0050402] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 10/19/2012] [Indexed: 11/19/2022] Open
Abstract
Previous studies indicated that estrogen could improve endothelial function. However, whether estrogen protects vascular complications of diabetes has yet to be clarified. The study was designed to investigate the action of 17ß-estradiol on vascular endothelium in streptozotocin (STZ)-induced diabetic rats. Ovariectomized female Sprague-Dawley rats were administered with streptozotocin to produce an ovariectomized-diabetic (OVS) model which manifested as dysfunction of aortic dilation and contraction ability. Meanwhile, OVS animals with 17ß-estradiol supplementation significantly improved aortic function. Accordingly, nitric oxide synthase-3 (NOS-3), Akt, PI3K and estrogen receptor α (ERα) protein expression in aorta declined in the OVS group. Such effects were partially restored by estrogen replacement. The presence of 17ß-estradiol similarly counteracted the reduction of cyclic guanosine monophosphate (cGMP), the enhanced expression of inducible NOS (NOS-2) and NO metabolites (nitrite and nitrate), as well as the increase of matrix metalloproteinase-9/tissue inhibitor of metalloproteinase-1 (MMP-9/TIMP-1), which is an index of arterial compliance. 17ß-estradiol could also decrease ROS production in vascular endothelium. In EA hy 926 cells we found that ER antagonist, wortmannin and Akt inhibitor could block improvement effects of 17ß-estradiol. These results strongly suggest that functional impairment of the ERα/NOS-3 signaling network in OVS animals was partially restored by 17ß-estradiol administration, which provides experimental support for estrogen recruitment to improve vascular outcomes in female diabetes after endogenous hormone depletion.
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Affiliation(s)
- Yi Han
- Department of Geriatrics, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China
| | - Xiaozhen Li
- State Key Laboratory of Reproductive Medicine, Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Suming Zhou
- Department of Geriatrics, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China
| | - Guoliang Meng
- State Key Laboratory of Reproductive Medicine, Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Yujiao Xiao
- State Key Laboratory of Reproductive Medicine, Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Wen Zhang
- State Key Laboratory of Reproductive Medicine, Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Zhuoying Wang
- State Key Laboratory of Reproductive Medicine, Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Liping Xie
- State Key Laboratory of Reproductive Medicine, Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Zhen Liu
- State Key Laboratory of Reproductive Medicine, Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Hui Lu
- State Key Laboratory of Reproductive Medicine, Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Yong Ji
- State Key Laboratory of Reproductive Medicine, Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing, People’s Republic of China
- * E-mail:
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Nemoto S, Taguchi K, Matsumoto T, Kamata K, Kobayashi T. Pravastatin normalizes ET-1-induced contraction in the aorta of type 2 diabetic OLETF rats by suppressing the KSR1/ERK complex. Am J Physiol Heart Circ Physiol 2012; 303:H893-902. [DOI: 10.1152/ajpheart.01128.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelin (ET)-1 is a likely candidate for a key role in diabetic vascular complications. In the present study, we hypothesized that treatment with pravastatin (an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase) would normalize the ET-1-induced contraction in aortas isolated from type 2 diabetic Otsuka Long-Evans Tokushima fatty (OLETF) rats. Contractile responses were examined by measuring isometric force in endothelium-denuded aortic helical strips from four groups: Long-Evans Tokushima Otsuka (LETO; genetic control), OLETF (type 2 diabetic), pravastatin-treated LETO, and pravastatin-treated OLETF rats. Both immunoblot analysis and immunoprecipitation assays were used to examine Src, protein phosphatase (PP)2A, kinase suppressor of Ras (KSR)1, and ERK signaling pathway protein levels and activities. In endothelium-denuded aortas isolated from OLETF rats at the chronic stage of diabetes (56–60 wk) (vs. those from age-matched LETO rats), we found the following: 1) ET-1-induced contraction was enhanced, 2) ERK1/2 phosphorylation was increased, 3) phosphorylations of KSR1 and PP2A were reduced (i.e., enhancement of the kinase active state), 4) ERK1/2-KSR1 complexes were increased, and 5) Src tyrosine kinase activity was diminished. Endothelium-denuded aortas isolated from OLETF rats treated with pravastatin (10 mg/kg po, daily for 4 wk) exhibited normalized ET-1-induced contractions and suppressed ET-1-stimulated ERK phosphorylation, with the associated phosphorylated KSR1 and phosphorylated PP2A levels being increased toward normal levels. These results suggest that in type 2 diabetic rats, pravastatin normalizes ET-1-induced contraction in aortic smooth muscle via a suppression of PP2A/KSR1/ERK activities after an enhancement of Src kinase activity.
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Affiliation(s)
- Shingo Nemoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan
| | - Kumiko Taguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan
| | - Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan
| | - Katsuo Kamata
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan
| | - Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan
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Taguchi K, Matsumoto T, Kamata K, Kobayashi T. Angiotensin II type 2 receptor-dependent increase in nitric oxide synthase activity in the endothelium of db/db mice is mediated via a MEK pathway. Pharmacol Res 2012; 66:41-50. [DOI: 10.1016/j.phrs.2012.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/15/2012] [Accepted: 02/27/2012] [Indexed: 01/01/2023]
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Nemoto S, Kobayashi T, Taguchi K, Matsumoto T, Kamata K. Losartan improves aortic endothelium-dependent relaxation via proline-rich tyrosine kinase 2/Src/Akt pathway in type 2 diabetic Goto-Kakizaki rats. Am J Physiol Heart Circ Physiol 2011; 301:H2383-94. [DOI: 10.1152/ajpheart.00178.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In diabetic states, endothelial dysfunction is related to vascular complications. We hypothesized that insulin-induced relaxation and the associated proline-rich tyrosine kinase 2 (Pyk2)/Src/Akt pathway would be abnormal in aortas from the Goto-Kakizaki (GK) type 2 diabetic rat, which exhibits hyperglycemia/insulin resistance, and that losartan treatment of such rats (25 mg·kg−1·day−1 for 2 wk) would correct these abnormalities. Endothelium-dependent relaxation was by measuring isometric force in helical strips of aortas from four groups, each of 30 rats: normal Wistar (control), GK (diabetic), losartan-treated normal, and losartan-treated GK. Pyk2, Src, and Akt/endothelial nitric oxide synthase (eNOS) signaling-pathway protein levels and activities were assayed mainly by Western blotting and partly by immunohistochemistry. In GK (vs. age-matched control) aortas, various insulin-stimulated levels [nitric oxide production and the phosphorylations of eNOS at Ser1177, of Akt at Thr308, of phosphoinositide-dependent kinase-1 (PDK1) at Ser241, of Src at Tyr416, and of Pyk2 at Tyr579] were all significantly decreased and unaffected by either Src inhibitor (PP2) or Pyk2 inhibitor (AG17), while the insulin-stimulated levels of insulin receptor substrate (IRS)-1 phosphorylation at Ser307, total-eNOS, and total-Akt were significantly increased. Losartan treatment normalized these altered levels. The insulin-stimulated phosphorylation levels of Src/PDK1/Akt/eNOS, but not of Pyk2, were decreased by PP2 in control and losartan-treated GK, but not in GK, aortas. These results suggest that in the GK diabetic aorta increased phospho-IRS-1 (at Ser307) and decreased Pyk2/Src activity inhibit insulin-induced stimulation of the PDK/Akt/eNOS pathway. The observed increase in phospho-IRS-1 (at Ser307) may result from increased angiotensin II activity.
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Affiliation(s)
- Shingo Nemoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
| | - Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
| | - Kumiko Taguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
| | - Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
| | - Katsuo Kamata
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
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Kim JG, Sung HJ, Ok SH, Kwon SC, Cheon KS, Kim HJ, Chang KC, Shin IW, Lee HK, Chung YK, Sohn JT. Calcium sensitization involved in dexmedetomidine-induced contraction of isolated rat aorta. Can J Physiol Pharmacol 2011; 89:681-9. [DOI: 10.1139/y11-065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Dexmedetomidine, a full agonist of the α2B-adrenoceptor that is mainly involved in vascular smooth muscle contraction, is primarily used for analgesia and sedation in intensive care units. High-dose dexmedetomidine produces hypertension in children and adults. The goal of this in vitro study was to investigate the role of the calcium (Ca2+) sensitization mechanism involving Rho-kinase, protein kinase C (PKC), and phosphoinositide 3-kinase (PI3-K) in mediating contraction of isolated rat aortic smooth muscle in response to dexmedetomidine. The effect of dexmedetomidine on the intracellular Ca2+ level ([Ca2+]i) and tension was measured simultaneously. Dexmedetomidine concentration–response curves were generated in the presence or absence of the following antagonists: rauwolscine, Y 27632, LY 294002, GF 109203X, and verapamil. Dexmedetomidine-induced phosphorylation of PKC and membrane translocation of Rho-kinase were detected with Western blotting. Rauwolscine, Y 27632, GF 109203X, LY 294002, and verapamil attenuated dexmedetomidine-induced contraction. The slope of the [Ca2+]i–tension curve for dexmedetomidine was higher than that for KCl. Dexmedetomidine induced phosphorylation of PKC and membrane translocation of Rho-kinase. These results suggest that dexmedetomidine-induced contraction involves a Ca2+ sensitization mechanism mediated by Rho-kinase, PKC, and PI3-K that is secondary to α2-adrenoceptor stimulation in rat aortic smooth muscle.
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Affiliation(s)
- Jae-Gak Kim
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju 660-702, Korea
| | - Hui-Jin Sung
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju 660-702, Korea
| | - Seong-Ho Ok
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju 660-702, Korea
| | - Seong-Chun Kwon
- Department of Physiology, Kwandong University College of Medicine, Kangneung 201-701, Korea
| | - Kwang Seong Cheon
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju 660-702, Korea
| | - Hye Jung Kim
- Department of Pharmacology, Gyeongsang National University School of Medicine, Jinju 660-772, Korea
| | - Ki Churl Chang
- Department of Pharmacology, Gyeongsang National University School of Medicine, Jinju 660-772, Korea
| | - Il-Woo Shin
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju 660-702, Korea
| | - Heon-Keun Lee
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju 660-702, Korea
| | - Young-Kyun Chung
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju 660-702, Korea
| | - Ju-Tae Sohn
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju 660-702, Korea
- Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 660-702, Korea
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Taguchi K, Kobayashi T, Matsumoto T, Kamata K. Dysfunction of endothelium-dependent relaxation to insulin via PKC-mediated GRK2/Akt activation in aortas of ob/ob mice. Am J Physiol Heart Circ Physiol 2011; 301:H571-83. [DOI: 10.1152/ajpheart.01189.2010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In diabetic states, hyperinsulinemia may negatively regulate Akt/endothelial nitric oxide synthase (eNOS) activation. Our main aim was to investigate whether and how insulin might negatively regulate Akt/eNOS activities via G protein-coupled receptor kinase 2 (GRK2) in aortas from ob/ob mice. Endothelium-dependent relaxation was measured in aortic rings from ob/ob mice (a type 2 diabetes model). GRK2, β-arrestin2, and Akt/eNOS signaling-pathway protein levels and activities were mainly assayed by Western blotting. Plasma insulin was significantly elevated in ob/ob mice. Insulin-induced relaxation was significantly decreased in the ob/ob aortas [vs. age-matched control (lean) ones]. The response in ob/ob aortas was enhanced by PKC inhibitor or GRK2 inhibitor. Akt (at Thr308) phosphorylation and eNOS (at Ser1177) phosphorylation, and also the β-arrestin2 protein level, were markedly decreased in the membrane fraction of insulin-stimulated ob/ob aortas (vs. insulin-stimulated lean ones). These membrane-fraction expressions were enhanced by GRK2 inhibitor and by PKC inhibitor in the ob/ob group but not in the lean group. PKC activity was much greater in ob/ob than in lean aortas. GRK2 protein and activity levels were increased in ob/ob and were greatly reduced by GRK2 inhibitor or PKC inhibitor pretreatment. These results suggest that in the aorta in diabetic mice with hyperinsulinemia an upregulation of GRK2 and a decrease in β-arrestin2 inhibit insulin-induced stimulation of the Akt/eNOS pathway and that GRK2 overactivation may result from an increase in PKC activity.
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Affiliation(s)
- Kumiko Taguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
| | - Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
| | - Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
| | - Katsuo Kamata
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
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Takenouchi Y, Kobayashi T, Taguchi K, Matsumoto T, Kamata K. Relationship among superoxide-related enzyme, PPARs, and endothelium-dependent relaxation in murine aortas previously organ-cultured in high-glucose conditions. Can J Physiol Pharmacol 2010; 88:760-9. [PMID: 20651824 DOI: 10.1139/y10-045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The aim of the present study was to investigate the relationship among superoxide anion, peroxisome proliferator-activated receptors (PPARs), and endothelium-dependent relaxation in murine aortas organ-cultured in a high-glucose condition. Aortas organ-cultured with a high concentration of glucose (40 mmol/L, 20 h; HG group) exhibited the following characteristics (versus aortas cultured in serum-free medium): (i) significantly weaker relaxation to acetylcholine, but unchanged relaxation to SNP and unchanged contractions to norepinephrine and isotonic K+, (ii) significantly greater superoxide generation (indicated by the amount of nitroblue tetrazolium reduced, (iii) significantly higher protein expression levels of gp91phox, NAD(P)H oxidase subunits, and endothelial NO synthase, (iv) significantly lower protein expression level of Mn-superoxide dismutase (SOD), and (v) markedly greater reduction in the protein expression of PPARgamma than in that of PPARalpha. The HG-induced impairment of endothelium-dependent relaxation was prevented by cotreatment with tempol (a SOD mimetic). These results suggest that in the mouse aorta, exposure to high glucose levels may lead to an excessive generation of superoxide via increased gp91phox and decreased Mn-SOD protein expression and that this may in turn trigger an impairment of endothelium-dependent relaxation. Moreover, such protein changes in gp91phox and Mn-SOD may be secondary to a decreased expression of PPARgamma protein.
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Affiliation(s)
- Yasuhiro Takenouchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
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12
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Pu Q, Zhuang D, Thakran S, Hassid A. Mechanisms related to NO-induced motility in differentiated rat aortic smooth muscle cells. Am J Physiol Heart Circ Physiol 2010; 300:H101-8. [PMID: 21037226 DOI: 10.1152/ajpheart.00342.2010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nitric oxide (NO) is thought to play an important role as an inhibitor of vascular cell proliferation, motility, and neointima formation. This effect is mediated, in part, via the upregulation of protein tyrosine phosphatase (PTP)1B. Conversely, studies have reported that in presumably hyperinsulinemic mice fed a high-fat diet, NO enhances vascular remodeling, whereas a deficit of NO attenuates vascular remodeling. We have reported that in differentiated cultured smooth muscle cells treated with insulin, NO induces a motogenic effect that is dependent on Src homology-2 domain PTP 2 (SHP2) upregulation. In the present study, we describe novel mechanisms relevant to the motogenic effect of NO. Treatment of cultured cells with the selective angiontensin type 1 receptor antagonist losartan, but not with the selective angiotensin type 2 receptor antagonist PD-123319, blocked the comotogenic capacity of NO and insulin. Insulin and NO increased the secretion of ANG II into the culture media by 2- and 2.5-fold (P < 0.05), respectively, whereas treatment of cells with ANG II uncovered the motogenic effect of NO (1.4-fold above control, P < 0.05) and decreased the levels of PTP1B to 45% of control (P < 0.05). Suppression of PTP1B function was sufficient to uncover the motogenic effect of NO. The capacity of insulin to suppress PTP1B activity was blocked by losartan, implicating ANG II function in mediating this effect. Both insulin and ANG II induced the upregulation of phosphatidyl inositol 3-kinase (PI3K)-δ by two- to threefold (P < 0.05), and this effect was both necessary and sufficient to uncover NO-induced motogenesis. Finally, suppression of PTP1B function potentiated, whereas overexpression of PTP1B inhibited, SHP2-induced motogenesis. These results support the hypothesis that the comotogenic effect of insulin and NO occurs via an ANG II-mediated effect involving the suppression of PTP1B and upregulation of PI3K-δ and SHP2.
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Affiliation(s)
- Qinghua Pu
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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13
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Matsumoto T, Ishida K, Taguchi K, Kobayashi T, Kamata K. Short-term angiotensin-1 receptor antagonism in type 2 diabetic Goto-Kakizaki rats normalizes endothelin-1-induced mesenteric artery contraction. Peptides 2010; 31:609-17. [PMID: 20026366 DOI: 10.1016/j.peptides.2009.12.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 12/12/2009] [Accepted: 12/14/2009] [Indexed: 12/12/2022]
Abstract
Endothelin (ET)-1 and angiotensin II (Ang II) are likely candidates for a key role in diabetic vascular complications. We demonstrated previously that an enhanced ET-1-induced contraction is present in mesenteric arteries from Goto-Kakizaki (GK) rats at the chronic stage of type 2 diabetes. Here, we investigated whether short-term treatment of such rats with losartan, an angiotensin type 1 receptor antagonist, might normalize the ET-1-induced contraction. In mesenteric arteries from GK rats at the chronic stage (34-38 weeks) (vs. those from age-matched control Wistar rats): (1) the ET-1-induced contraction was enhanced, (2) the levels of ET-1 and Ang II were increased, (3) ET-1-stimulated ERK2 phosphorylation was increased, and (4) the ACh-induced endothelium-dependent relaxation was reduced. Mesenteric arteries isolated from such GK rats following treatment with losartan (25mg/kg/day for 2 weeks) exhibited reduced ET-1- and Ang II-induced contractions, suppressed ET-1-stimulated ERK phosphorylation, and increased ACh-induced relaxation, while the rats exhibited normalized plasma NO metabolism and their mesenteric arteries exhibited increased basal NO formation. However, such losartan treatment did not alter the increased levels of ET-1 and Ang II seen in GK mesenteric arteries. Our data suggest that within the timescale studied here, losartan normalizes ET-1-induced mesenteric artery contraction through a suppression of ERK activities and/or by normalizing endothelial function.
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Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, 4-41 Ebara 2-Chome, Shinagawa-ku, Tokyo 142-8501, Japan.
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14
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Matsumoto T, Ishida K, Taguchi K, Kobayashi T, Kamata K. Losartan normalizes endothelium-derived hyperpolarizing factor-mediated relaxation by activating Ca2+-activated K+ channels in mesenteric artery from type 2 diabetic GK rat. J Pharmacol Sci 2010; 112:299-309. [PMID: 20168046 DOI: 10.1254/jphs.09308fp] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Ca(2+)-activated K(+) (K(Ca)) channels are important for endothelium-derived hyperpolarizing factor (EDHF) signaling. Since treatment with angiotensin II receptor blockers (ARBs) improves vasculopathies in type 2 diabetic patients, we asked whether the EDHF-type relaxation and its associated K(Ca) channels [small (SK(Ca))-, intermediate (IK(Ca))-, and large (BK(Ca))-conductance channels] are abnormal in mesenteric arteries isolated from Goto-Kakizaki (GK) rats at the chronic stage of type 2 diabetes (34 - 38 weeks) and whether an ARBs (losartan, 25 mg . kg(-1) . day(-1) for 2 weeks) might correct these abnormalities. Although the acetylcholine chloride-induced EDHF-type relaxation in mesenteric arteries from GK rats was reduced versus the Wistar controls, it was significantly restored by losartan treatment. The SK(Ca)-blocker apamin or the IK(Ca)-blocker 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34) inhibited such relaxations in the losartan-treated or -untreated Wistar groups and in the losartan-treated GK group, but not in the losartan-untreated GK group. The BK(Ca)-blocker iberiotoxin had a significant inhibitory effect in only one of these groups, the losartan-treated GK. The relaxations induced by the SK(Ca)/IK(Ca) activator NS309 and the BK(Ca) activator NS1619, which were impaired in GK rats, were normalized by losartan treatment. We conclude that losartan improves EDHF-type relaxation in GK rats at least partly by normalizing SK(Ca)/IK(Ca) activities and increasing BK(Ca) activity.
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Affiliation(s)
- Takayuki Matsumoto
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan
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15
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Kobayashi T, Taguchi K, Nemoto S, Nogami T, Matsumoto T, Kamata K. Activation of the PDK-1/Akt/eNOS pathway involved in aortic endothelial function differs between hyperinsulinemic and insulin-deficient diabetic rats. Am J Physiol Heart Circ Physiol 2009; 297:H1767-75. [PMID: 19717727 DOI: 10.1152/ajpheart.00536.2009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In diabetic states, altered plasma insulin is likely to play key roles in 3-phosphoinositide-dependent protein kinase (PDK)/Akt pathway activation, in insulin resistance and in endothelial dysfunction. Since the molecular mechanism(s) remains unclear, we examined the relationship between the PDK/Akt/endothelial nitric oxide synthase (NOS) pathway and endothelial function in aortas from diabetic rats that were either insulin deficient or hyperinsulinemic. Untreated diabetic (diabetic) rats exhibited hyperglycemia and hypoinsulinemia, whereas high-insulin-treated diabetic (HI-diabetic) rats exhibited hyperinsulinemia. Aortas from the diabetic group displayed impaired endothelium-dependent relaxation in response to ACh, whereas the insulin-induced relaxation was increased. In HI-diabetic aortas, the ACh-induced relaxation was normal, but that induced by insulin was impaired. The insulin-induced relaxation was inhibited by treatment with an Akt inhibitor in control and diabetic aortas, but not in the HI-diabetic aorta. This inhibitory effect on insulin-induced relaxation was greater in diabetic aortas than in control aortas. In all groups, ACh-induced relaxation was unaffected by the above inhibitor. In the diabetic group, various insulin-stimulated levels (nitric oxide production, phosphorylation of endothelial NOS at Ser(1177), of Akt at Thr(308), and of PDK-1 at Ser(241)) were significantly increased, whereas, in the HI-diabetic group, these levels were all decreased (vs. control aortas). These results suggest that the plasma insulin level has a close relation to the level of aortic PDK-1/Akt (at Thr(308))/NOS activities, and that reduced actions of the PDK-1/Akt (at Thr(308)) signal pathway may contribute to the impairments of insulin-induced endothelial functions seen in hyperinsulinemic diabetes.
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Affiliation(s)
- Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Tokyo, Japan
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16
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Fekete A, Rosta K, Wagner L, Prokai A, Degrell P, Ruzicska E, Vegh E, Toth M, Ronai K, Rusai K, Somogyi A, Tulassay T, Szabo AJ, Ver A. Na+,K+-ATPase is modulated by angiotensin II in diabetic rat kidney--another reason for diabetic nephropathy? J Physiol 2008; 586:5337-48. [PMID: 18818245 DOI: 10.1113/jphysiol.2008.156703] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Angiotensin II (ANGII) plays a central role in the enhanced sodium reabsorption in early type 1 diabetes in man and in streptozotocin-induced (STZ) diabetic rats. This study investigates the effect of untreated STZ-diabetes leading to diabetic nephropathy in combination with ANGII treatment, on the abundance and localization of the renal Na(+),K(+)-ATPase (NKA), a major contributor of renal sodium handling. After 7 weeks of STZ-diabetes (i.v. 65 mg kg(-1)) a subgroup of control (C) and diabetic (D7) Wistar rats were treated with ANGII (s.c. minipump 33 microg kg(-1) h(-1) for 24 h; CA and D7A). We measured renal function and mRNA expression, protein level, Serin23 phosphorylation, subcellular distribution, and enzyme activity of NKA alpha-1 subunit in the kidney cortex. Diabetes increased serum creatinine and urea nitrogen levels (C versus D7), as did ANGII (C versus CA, D7 versus D7A). Both diabetes (C versus D7) and ANGII increased NKA alpha-1 protein level and enzyme activity (C versus CA, D7 versus D7A). Furthermore, the combination led to an additive increase (D7 versus D7A, CA versus D7A). NKA alpha-1 Ser23 phosphorylation was higher both in D7 and ANGII-treated rats in the non-cytoskeletal fraction, while no signal was detected in the cytoskeletal fraction. Control kidneys showed NKA alpha-1 immunopositivity on the basolateral membrane of proximal tubular cells, while both D7 and ANGII broadened NKA immunopositivity towards the cytoplasm. Our study demonstrates that diabetes mellitus (DM) increases the mRNA expression, protein level, Ser23 phosphorylation and enzyme activity of renal NKA, which is further elevated by ANGII. Despite an increase in total NKA quantity in diabetic nephropathy, the redistribution to the cystosol suggests the Na(+) pump is no longer functional. ANGII also caused translocation from the basolateral membrane, thus in diabetic states where ANGII level is acutely elevated, the loss of NKA will be exacerbated. This provides another mechanism by which ANGII blockade is likely to be protective.
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Affiliation(s)
- Andrea Fekete
- 1st Department of Pediatrics, Semmelweis University Budapest, H-1082, Budapest, Hungary
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17
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Kinoshita H, Matsuda N, Kaba H, Hatakeyama N, Azma T, Nakahata K, Kuroda Y, Tange K, Iranami H, Hatano Y. Roles of Phosphatidylinositol 3-Kinase-Akt and NADPH Oxidase in Adenosine 5′-Triphosphate–Sensitive K
+
Channel Function Impaired by High Glucose in the Human Artery. Hypertension 2008; 52:507-13. [DOI: 10.1161/hypertensionaha.108.118216] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study was designed to examine roles of the phosphatidylinositol 3-kinase-Akt pathway and reduced nicotinamide-adenine dinucleotide phosphate oxidases in the reduced ATP-sensitive K
+
channel function via superoxide produced by high glucose in the human artery. We evaluated the activity of the phosphatidylinositol 3-kinase-Akt pathway, as well as reduced nicotinamide-adenine dinucleotide phosphate oxidases, the intracellular levels of superoxide and ATP-sensitive K
+
channel function in the human omental artery without endothelium. Levels of the p85-α subunit and reduced nicotinamide-adenine dinucleotide phosphate oxidase subunits, including p47phox, p22phox, and Rac-1, increased in the membrane fraction from arteries treated with
d
-glucose (20 mmol/L) accompanied by increased intracellular superoxide production. High glucose simultaneously augmented Akt phosphorylation at Ser 473, as well as Thr 308 in the human vascular smooth muscle cells. A phosphatidylinositol 3-kinase inhibitor LY294002, as well as tiron and apocynin, restored vasorelaxation and hyperpolarization in response to an ATP-sensitive K
+
channel opener levcromakalim. Therefore, it can be concluded that the activation of the phosphatidylinositol 3-kinase-Akt pathway, in combination with the translocation of p47phox, p22phox, and Rac-1, contributes to the superoxide production induced by high glucose, resulting in the impairment of ATP-sensitive K
+
channel function in the human visceral artery.
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Affiliation(s)
- Hiroyuki Kinoshita
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Naoyuki Matsuda
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Hikari Kaba
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Noboru Hatakeyama
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Toshiharu Azma
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Katsutoshi Nakahata
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Yasuhiro Kuroda
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Kazuaki Tange
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Hiroshi Iranami
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
| | - Yoshio Hatano
- From the Department of Anesthesiology (H. Kinoshita, K.N., K.T., Y.H.), Wakayama Medical University, Wakayama; Departments of Primary Care and Emergency Medicine (N.M.), Graduate School of Medicine, Kyoto University, Kyoto; Departments of Molecular Medical Pharmacology (H. Kaba) and Anesthesiology (N.H.), Toyama University School of Medicine, Toyama; Department of Anesthesiology (T.A.), Saitama Medical University, Moroyama; Department of Emergency Medical Center (Y.K.), Kagawa University Hospital,
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18
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Diabetic state, high plasma insulin and angiotensin II combine to augment endothelin-1-induced vasoconstriction via ETA receptors and ERK. Br J Pharmacol 2008; 155:974-83. [PMID: 19029977 DOI: 10.1038/bjp.2008.327] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE Mechanisms associated with the enhanced contractile response to endothelin-1 in hyperinsulinaemic diabetes have been examined using the rat aorta. Functions for angiotensin II, endothelin-1 receptor expression and extracellular signal-regulated kinase (ERK) have been investigated. EXPERIMENTAL APPROACH Streptozotocin-induced diabetic rats were infused with angiotensin II or, following insulin treatment, were treated with losartan, an angiotensin II receptor antagonist. Contractions of aortic strips with or without endothelium, in response to endothelin-1 and angiotensin II, were examined in vitro. Aortic ET(A) receptors and ERK/MEK expression were measured by western blotting. KEY RESULTS Insulin-treated diabetic rats exhibited increases in plasma insulin, angiotensin II and endothelin-1. The systolic blood pressure and endothelin-1-induced contractile responses in aortae in vitro were enhanced in insulin-treated diabetic rats and blunted by chronic losartan administration. LY294002 (phosphatidylinositol 3-kinase inhibitor) and/or PD98059 (MEK inhibitor) diminished the enhanced contractile response to endothelin-1 in aortae from insulin-treated diabetic rats. ET(A) and ET(B) receptors, ERK-1/2 and MEK-1/2 protein expression and endothelin-1-stimulated ERK phosphorylation were all increased in aortae from insulin-treated diabetic rats. Such increases were blunted by chronic losartan administration. Endothelin-1-induced contraction was significantly higher in aortae from angiotensin II-infused diabetic rats. angiotensin II-infusion increased ERK phosphorylation, but the expression of endothelin receptors and ERK/MEK proteins remained unchanged. CONCLUSIONS AND IMPLICATIONS These results suggest that the combination of high plasma angiotensin II and insulin with a diabetic state induced enhancement of endothelin-1-induced vasoconstriction, ET(A) receptor expression and ERK expression/activity in the aorta. Losartan improved both the diabetes-related abnormalities and the diabetic hypertension.
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KOBAYASHI T. Possible Involvement of Insulin and Oxidative Stress in Vascular Dysfunction of Diabetic Mellitus. YAKUGAKU ZASSHI 2008; 128:1013-21. [DOI: 10.1248/yakushi.128.1013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Tsuneo KOBAYASHI
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University
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20
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Zhuang D, Pu Q, Ceacareanu B, Chang Y, Dixit M, Hassid A. Chronic insulin treatment amplifies PDGF-induced motility in differentiated aortic smooth muscle cells by suppressing the expression and function of PTP1B. Am J Physiol Heart Circ Physiol 2008; 295:H163-73. [PMID: 18456732 DOI: 10.1152/ajpheart.01105.2007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hyperinsulinemia plays a major role in the pathogenesis of vascular disease. Restenosis occurs at an accelerated rate in hyperinsulinemia and is dependent on increased vascular smooth muscle cell movement from media to neointima. PDGF plays a critical role in mediating neointima formation in models of vascular injury. We have reported that PDGF increases the levels of protein tyrosine phosphatase PTP1B and that PTP1B suppresses PDGF-induced motility in cultured cells and that it attenuates neointima formation in injured carotid arteries. Others have reported that insulin enhances the mitogenic and motogenic effects of PDGF in cultured smooth muscle cells and that hyperinsulinemia promotes vascular remodeling. In the present study, we tested the hypothesis that insulin amplifies PDGF-induced cell motility by suppressing the expression and function of PTP1B. We found that chronic but not acute treatment of cells with insulin enhances PDGF-induced motility in differentiated cultured primary rat aortic smooth muscle cells and that it suppresses PDGF-induced upregulation of PTP1B protein. Moreover, insulin suppresses PDGF-induced upregulation of PTP1B mRNA levels, PTP1B enzyme activity, and binding of PTP1B to the PDGF receptor-beta, and it enhances PDGF-induced PDGF receptor phosphotyrosylation. Treatment with insulin induces time-dependent upregulation of phosphatidylinositol 3-kinase (PI3-kinase)-delta and activation of Akt, an enzyme downstream of PI3-kinase. Finally, inhibition of PI3-kinase activity, or its function, by pharmacological or genetic means rescues PTP1B activity in insulin-treated cells. These observations uncover novel mechanisms that explain how insulin amplifies the motogenic capacity of the pivotal growth factor PDGF.
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Affiliation(s)
- Daming Zhuang
- Dept. of Physiology, Univ. of Tennessee, Memphis, TN 38163, USA
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21
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Farghaly HSM, Blagbrough IS, Medina-Tato DA, Watson ML. Interleukin 13 increases contractility of murine tracheal smooth muscle by a phosphoinositide 3-kinase p110delta-dependent mechanism. Mol Pharmacol 2008; 73:1530-7. [PMID: 18276774 DOI: 10.1124/mol.108.045419] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The Th2 cytokine interleukin (IL) 13 can elicit a number of responses consistent with a key role in the pathogenesis of asthma. We have used pharmacological and genetic approaches to demonstrate the role of signaling via the class I phosphoinositide 3-kinase p110delta isoform in IL-13-induced hyper-responsiveness of murine tracheal smooth muscle contractility in vitro. IL-13 treatment of tracheal tissue is associated with an early activation of phosphoinositide 3-kinase (PI3K), as assessed by phosphorylation of Akt. Tracheal smooth muscle contractility is enhanced by overnight incubation with IL-13, resulting in increased maximal contractions (E(max)) to carbachol (CCh) and KCl. Inhibition of PI3K by the non-isoform-selective inhibitors wortmannin or 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), or the selective inhibitor of the PI3K p110delta isoform 2-(6-aminopurin-9-ylmethyl)-5-methyl-3-O-tolyl-3H-quinazolin-4-one (IC87114), prevented IL-13-induced hyper-responsiveness. Consistent with a role for PI3K p110delta in IL-13-induced hyper-responsiveness, IL-13 was unable to induce hyper-responsiveness in tissues from mice expressing the catalytically inactive form of p110delta (p110delta(D910A)). These data indicate that IL-13 contributes to tracheal smooth muscle hyper-responsiveness via the PI3K p110delta isoform. In addition to previously reported effects on airway inflammation, inhibition of PI3K p110delta may be a useful target for the treatment of asthma by preventing IL-13-induced airway smooth muscle hyper-responsiveness.
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Affiliation(s)
- Hanan S M Farghaly
- Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK
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22
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Jackson EK, Gillespie DG, Zhu C, Ren J, Zacharia LC, Mi Z. Alpha2-adrenoceptors enhance angiotensin II-induced renal vasoconstriction: role for NADPH oxidase and RhoA. Hypertension 2008; 51:719-26. [PMID: 18250367 DOI: 10.1161/hypertensionaha.107.096297] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Alpha(2)-adrenoceptors potentiate renal vascular responses to angiotensin II via coincident signaling at phospholipase C. This leads to increased activation of the phospholipase C/protein kinase C/c-src pathway. Studies suggest that c-src activates the reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase/superoxide system, and reactive oxygen species stimulate the RhoA/Rho kinase pathway. Therefore, we hypothesized that NADPH oxidase/superoxide and RhoA/Rho kinase are downstream components of the signal transduction pathway that mediate the interaction between alpha(2)-adrenoceptors and angiotensin II on renal vascular resistance. In rat kidneys, both in vivo and in vitro, intrarenal infusions of angiotensin II increased renal vascular resistance, and UK14,304 (alpha(2)-adrenoceptor agonist) enhanced this response. Intrarenal Tempol (superoxide dismutase mimetic) or Y27632 (Rho kinase inhibitor) abolished the interaction between UK14,304 and angiotensin II both in vivo and in vitro. The interaction was also blocked by inhibitors of NADPH oxidase (in vivo using chronic gp91ds-tat administration and in vitro with diphenyleneiodonium). In cultured preglomerular vascular smooth muscle cells, UK14,304 enhanced angiotensin II-induced intracellular superoxide (2-hydroxyethidium production) and potentiated activation of RhoA (Western blot of activated RhoA bound to the binding domain of rhotekin). The interaction between angiotensin II and UK14,304 on superoxide generation and RhoA activation was blocked by inhibitors of phospholipase C (U73312), protein kinase C (GF109203X), c-src (PP1), NADPH oxidase (diphenyleneiodonium), or superoxide (Tempol). We conclude that NADPH oxidase/superoxide and RhoA/Rho kinase are involved in the interaction between alpha(2)-adrenoceptors and angiotensin II on renal vascular resistance by mediating signaling events downstream of the phospholipase C/protein kinase C/c-src pathway.
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Affiliation(s)
- Edwin K Jackson
- Center for Clinical Pharmacology, Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA. edj+@pitt.edu
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Takenouchi Y, Kobayashi T, Matsumoto T, Kamata K. Possible Involvement of Akt Activity in Endothelial Dysfunction in Type 2 Diabetic Mice. J Pharmacol Sci 2008; 106:600-8. [DOI: 10.1254/jphs.fp0071684] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Ma L, Zhu B, Chen X, Liu J, Guan Y, Ren J. Abnormalities of sarcoplasmic reticulum Ca2+ mobilization in aortic smooth muscle cells from streptozotocin-induced diabetic rats. Clin Exp Pharmacol Physiol 2007; 35:568-73. [PMID: 18067595 DOI: 10.1111/j.1440-1681.2007.04832.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. Previously, we found that contractions in response to receptor-dependent (i.e. a(1)-adrenoceptor agonist phenylephrine) and -independent (i.e. cyclopiazonic acid) stimuli are decreased in rat aorta during late diabetes. The aim of the present study was to further investigate the changes of intracellular Ca(2+) homeostasis in diabetic aortic smooth muscle cells. Functional changes of inositol 1,4,5-trisphosphate (IP(3))- and ryanodine-sensitive Ca(2+) stores of the sarcoplasmic reticulum (SR) were evaluated using Fluo-3 acetoxymethyl ester fluorescence, western blot and organ bath techniques. 2. In aortic smooth muscle cells from diabetic rats, the Ca(2+) release and Ca(2+) influx caused by both 10 mmol/L phenylephrine (depletion of IP(3)-sensitive Ca(2+) stores) and 1 mmol/L ryanodine (depletion of ryanodine-sensitive Ca(2+) stores) were both significantly decreased compared with control. Moreover, protein expression levels of IP(3) (260 kDa) and ryanodine receptors (500 kDa) were reduced by 31.8 +/- 7.7 and 69.2 +/- 8.4%, respectively, in aortas from diabetic rats compared with those from control rats. 3. In diabetic rat aorta, phenylephrine-induced contractility was decreased to approximately two-thirds of that in controls, whereas ryanodine alone did not cause obvious contraction in aortas from either control or diabetic rats. 4. The present results suggest that the hyporeactivity of aortic smooth muscle to vasoconstrictors in diabetes results mainly from changes to the IP(3)-sensitive Ca(2+) release pathway. The SR Ca(2+) signalling pathway plays a crucial role in the development of diabetic vascular complications.
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Affiliation(s)
- Li Ma
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan Medical College, Sun Yat-Sen University, Guangzhou, China
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Kobayashi T, Taguchi K, Takenouchi Y, Matsumoto T, Kamata K. Insulin-induced impairment via peroxynitrite production of endothelium-dependent relaxation and sarco/endoplasmic reticulum Ca(2+)-ATPase function in aortas from diabetic rats. Free Radic Biol Med 2007; 43:431-43. [PMID: 17602959 DOI: 10.1016/j.freeradbiomed.2007.04.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 03/06/2007] [Accepted: 04/23/2007] [Indexed: 12/01/2022]
Abstract
We designed this study to determine whether a high insulin level and a diabetic state need to exist together to cause an impairment of endothelium-dependent relaxation. In diabetic rat aortas organ-cultured with insulin [vs both control rat aortas cultured with insulin and diabetic rat aortas cultured in serum-free medium]: (1) the relaxation responses to both acetylcholine (endothelium-dependent relaxation) and Angeli's salt (nitric oxide donor) were significantly weaker, (2) acetylcholine-stimulated nitric oxide production was significantly smaller, (3) superoxide and nitric oxide production into the culture medium was greater, and (4) the levels of both nitrotyrosine and tyrosine-nitrated sarco/endoplasmic reticulum calcium ATPase (SERCA) protein were greater. The insulin-induced effects were prevented by cotreatment with either a superoxide scavenger or a peroxynitrite scavenger. After preincubation with an irreversible SERCA inhibitor, the relaxation induced by the nitric oxide donor was significantly impaired in control aortas cultured with or without insulin and in diabetic aortas cultured without insulin, but not in diabetic aortas cultured with insulin. These results suggest that the coexistence of a high insulin level and an established diabetic state may lead to an excessive generation of peroxynitrite, and that this may in turn trigger an impairment of endothelium-dependent relaxation via a decrease in SERCA function.
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Affiliation(s)
- Tsuneo Kobayashi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
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Bisht B, Goel HL, Dey CS. Focal adhesion kinase regulates insulin resistance in skeletal muscle. Diabetologia 2007; 50:1058-69. [PMID: 17333113 DOI: 10.1007/s00125-007-0591-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Accepted: 10/15/2006] [Indexed: 10/23/2022]
Abstract
AIMS/HYPOTHESIS On the basis of our previous studies, we investigated the possible role of focal adhesion kinase (FAK) in the development of insulin resistance in skeletal muscle, a major organ responsible for insulin-stimulated glucose uptake. MATERIALS AND METHODS Insulin-resistant C2C12 skeletal muscle cells were transfected with FAK wild-type or FAK mutant plasmids, knocked down using small interfering RNA (siRNA), and their effects on the levels and activities of insulin-signalling molecules and on glucose uptake were determined. RESULTS A significant decrease in tyrosine phosphorylation of FAK in insulin-resistant C2C12 cells was observed. A similar decrease was observed in skeletal muscle obtained from insulin-resistant Sprague-Dawley rats fed a high-fat diet. Increased levels of FAK in insulin-resistant C2C12 skeletal muscle cells increased insulin sensitivity and glucose uptake. These effects were reversed by an increase in the level of kinase activity mutant FAK or suppression of endogenous FAK by siRNA. FAK was also found to interact downstream with insulin receptor substrate-1, phosphatidylinositol 3-kinase and protein kinase C and glycogen synthase kinase 3beta, leading to translocation of glucose transporter 4 and resulting in the regulation of glucose uptake. CONCLUSIONS/INTERPRETATION The present study provides strong evidence that the modulation of FAK level regulates the insulin sensitivity of skeletal muscle cells. The results demonstrate a direct role of FAK in insulin-resistant skeletal muscle cells for the first time.
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Affiliation(s)
- B Bisht
- Signal Transduction Research Laboratory, Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Chandigarh 160062, India
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Taguchi K, Kobayashi T, Hayashi Y, Matsumoto T, Kamata K. Enalapril improves impairment of SERCA-derived relaxation and enhancement of tyrosine nitration in diabetic rat aorta. Eur J Pharmacol 2006; 556:121-8. [PMID: 17196960 DOI: 10.1016/j.ejphar.2006.11.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Revised: 11/01/2006] [Accepted: 11/06/2006] [Indexed: 02/07/2023]
Abstract
We investigated the involvement of angiotensin II and vascular smooth muscle sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) function in the impaired NO-induced relaxation seen in established streptozotocin-induced diabetes. Plasma angiotensin II levels, which were elevated in untreated diabetic rats (vs age-matched controls), were improved by treatment with the angiotensin-converting enzyme inhibitor enalapril. Systolic blood pressure was significantly decreased in chronic enalapril-treated diabetics (vs the other two groups). Intact aortae from diabetic rats and chronic angiotensin II-infused control rats, but not those from diabetic rats treated with enalapril, showed impaired endothelium-dependent relaxations to acetylcholine (vs controls). The relaxation induced by Angeli's Salt (a NO donor) was significantly impaired in endothelium-denuded aortae from diabetic rats (vs controls) but it was normalised by enalapril treatment. After preincubation with the irreversible SERCA inhibitor, thapsigargin, the relaxation induced by Angeli's Salt was significantly impaired in endothelium-denuded aortae from the controls, but not from the diabetics, and there was no significant difference between the thapsigargin-treated groups. Nitrotyrosine, an indirect marker of peroxynitrite, was markedly increased in aortic smooth muscle from diabetic rats, while chronic enalapril administration reduced this increase. These results suggest that in streptozotocin-induced diabetic rats, excessive angiotensin II production may lead to the generation of peroxynitrite and that this may in turn trigger a dysfunction of vascular smooth muscle SERCA. Enalapril improved the diabetes-related impairments.
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Affiliation(s)
- Kumiko Taguchi
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142-8501, Japan
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