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Dong Y, Wang J, Yang C, Bao J, Liu X, Chen H, Zhang X, Shi W, Zhang L, Qi Q, Li Y, Wang S, Ma R, Cong B, Zhang G. Phosphorylated CPI-17 and MLC2 as Biomarkers of Coronary Artery Spasm-Induced Sudden Cardiac Death. Int J Mol Sci 2024; 25:2941. [PMID: 38474189 PMCID: PMC10932290 DOI: 10.3390/ijms25052941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/19/2024] [Accepted: 02/28/2024] [Indexed: 03/14/2024] Open
Abstract
Coronary artery spasm (CAS) plays an important role in the pathogeneses of various ischemic heart diseases and has gradually become a common cause of life-threatening arrhythmia. The specific molecular mechanism of CAS has not been fully elucidated, nor are there any specific diagnostic markers for the condition. Therefore, this study aimed to examine the specific molecular mechanism underlying CAS, and screen for potential diagnostic markers. To this end, we successfully constructed a rat CAS model and achieved in vitro culture of a human coronary-artery smooth-muscle cell (hCASMC) contraction model. Possible molecular mechanisms by which protein kinase C (PKC) regulated CAS through the C kinase-potentiated protein phosphatase 1 inhibitor of 17 kDa (CPI-17)/myosin II regulatory light chain (MLC2) pathway were studied in vivo and in vitro to screen for potential molecular markers of CAS. We performed hematoxylin and eosin staining, myocardial zymogram, and transmission electron microscopy to determine myocardial and coronary artery injury in CAS rats. Then, using immunohistochemical staining, immunofluorescence staining, and Western blotting, we further demonstrated a potential molecular mechanism by which PKC regulated CAS via the CPI-17/MLC2 pathway. The results showed that membrane translocation of PKCα occurred in the coronary arteries of CAS rats. CPI-17/MLC2 signaling was observably activated in coronary arteries undergoing CAS. In addition, in vitro treatment of hCASMCs with angiotensin II (Ang II) increased PKCα membrane translocation while consistently activating CPI-17/MLC2 signaling. Conversely, GF-109203X and calphostin C, specific inhibitors of PKC, inactivated CPI-17/MLC2 signaling. We also collected the coronary artery tissues from deceased subjects suspected to have died of CAS and measured their levels of phosphorylated CPI-17 (p-CPI-17) and MLC2 (p-MLC2). Immunohistochemical staining was positive for p-CPI-17 and p-MLC2 in the tissues of these subjects. These findings suggest that PKCα induced CAS through the CPI-17/MLC2 pathway; therefore, p-CPI-17 and p-MLC2 could be used as potential markers for CAS. Our data provide novel evidence that therapeutic strategies against PKC or CPI-17/MLC2 signaling might be promising in the treatment of CAS.
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Affiliation(s)
- Yiming Dong
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Jianfeng Wang
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Chenteng Yang
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Junxia Bao
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Xia Liu
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Hao Chen
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Xiaojing Zhang
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Weibo Shi
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Lihua Zhang
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Qian Qi
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Yingmin Li
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Songjun Wang
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Rufei Ma
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Bin Cong
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
| | - Guozhong Zhang
- Hebei Key Laboratory of Forensic Medicine, Collaborative Innovation Center of Forensic Medical Molecular Identification, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China; (Y.D.); (J.W.); (C.Y.); (J.B.); (X.L.); (H.C.); (X.Z.); (W.S.); (L.Z.); (Q.Q.); (Y.L.); (S.W.); (R.M.); (B.C.)
- Hebei Province Laboratory of Experimental Animal, Shijiazhuang 050017, China
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Miao LN, Pan D, Shi J, Du JP, Chen PF, Gao J, Yu Y, Shi DZ, Guo M. Role and Mechanism of PKC-δ for Cardiovascular Disease: Current Status and Perspective. Front Cardiovasc Med 2022; 9:816369. [PMID: 35242825 PMCID: PMC8885814 DOI: 10.3389/fcvm.2022.816369] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/11/2022] [Indexed: 12/18/2022] Open
Abstract
Protein kinase C (PKC) is a protein kinase with important cellular functions. PKC-δ, a member of the novel PKC subfamily, has been well-documented over the years. Activation of PKC-δ plays an important regulatory role in myocardial ischemia/reperfusion (IRI) injury and myocardial fibrosis, and its activity and expression levels can regulate pathological cardiovascular diseases such as atherosclerosis, hypertension, cardiac hypertrophy, and heart failure. This article aims to review the structure and function of PKC-δ, summarize the current research regarding its activation mechanism and its role in cardiovascular disease, and provide novel insight into further research on the role of PKC-δ in cardiovascular diseases.
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Affiliation(s)
- Li-na Miao
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Department of Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Deng Pan
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Department of Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Junhe Shi
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jian-peng Du
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Heart Institute of Chinese Medicine, China Academy of Chinese Medical Sciences, Beijing, China
| | - Peng-fei Chen
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jie Gao
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Heart Institute of Chinese Medicine, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yanqiao Yu
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Department of Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Da-Zhuo Shi
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Heart Institute of Chinese Medicine, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Da-Zhuo Shi
| | - Ming Guo
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- China Heart Institute of Chinese Medicine, China Academy of Chinese Medical Sciences, Beijing, China
- Ming Guo
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The impact of sleep disorders on microvascular complications in patients with type 2 diabetes (SLEEP T2D): the protocol of a cohort study and feasibility randomised control trial. Pilot Feasibility Stud 2021; 7:80. [PMID: 33752759 PMCID: PMC7982768 DOI: 10.1186/s40814-021-00817-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 03/09/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Obstructive sleep apnoea (OSA) is very common in patients with type 2 diabetes (T2D). We and others have shown that OSA was associated with diabetes-related microvascular complications in patients with T2D in cross-sectional and longitudinal studies and that compliance with continuous positive airway pressure (CPAP) reduced the progression of microvascular complications. Hence, we hypothesised that adequate CPAP reduces the development of microvascular complication in patients with T2D. METHODS SLEEP T2D is a cohort study with embedded feasibility, open-label, parallel-arm, randomised control trial (RCT) over 2 years. The primary aim is the feasibility of conducting a definitive RCT assessing the impact of CPAP on chronic kidney disease and other microvascular complications in patients with T2D. The main parameters are to assess willingness of participants to be randomised, follow-up rates, CPAP adherence/compliance, to optimise the choice of outcome measures for a substantive trial, and to identify the parameters for sample size calculations. The secondary aims of the study are related to the impact of CPAP, sleep-related disorders, and sleep chronotype on a variety of diabetes-related end points. The study participants were recruited from the T2D services in multiple NHS trusts across England. The main exclusion criteria for the cohort study are as follows: T1D, eGFR < 15 mL/min/1.73 m2, known OSA, active malignancy or chronic kidney disease from reasons other than diabetes, pregnancy, professional drivers, and a history of falling asleep whilst driving within last 2 years. The main exclusion criteria from the RCT were as follows: Apnoea-Hypopnoea Index < 10 and Epworth Sleepiness Score ≥ 11. Study participants were extensively phenotyped clinically and biochemically. The OSA diagnosis was based on multichannel portable device (ApneaLink AirTM, Resmed). DISCUSSION The feasibility RCT will help us design the future RCT to assess the impact of CPAP on diabetes-related microvascular complications. The cohort study will generate preliminary data regarding the impact of sleep quality, duration, and chronotype on diabetes-related outcomes which could lead to further mechanistic and interventional studies. TRIAL REGISTRATION ISRCTN, ISRCTN12361838 . Registered 04 April 2018, Protocol version: v5.0 02.12.19.
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Endothelin-1-Mediated Mechanisms in the Carotid Body Modulates Cardiovascular Responses in Rats Exposed to Chronic Intermittent Hypoxia. Int J Pept Res Ther 2018. [DOI: 10.1007/s10989-018-9794-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Liu Z, Khalil RA. Evolving mechanisms of vascular smooth muscle contraction highlight key targets in vascular disease. Biochem Pharmacol 2018; 153:91-122. [PMID: 29452094 PMCID: PMC5959760 DOI: 10.1016/j.bcp.2018.02.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/12/2018] [Indexed: 12/11/2022]
Abstract
Vascular smooth muscle (VSM) plays an important role in the regulation of vascular function. Identifying the mechanisms of VSM contraction has been a major research goal in order to determine the causes of vascular dysfunction and exaggerated vasoconstriction in vascular disease. Major discoveries over several decades have helped to better understand the mechanisms of VSM contraction. Ca2+ has been established as a major regulator of VSM contraction, and its sources, cytosolic levels, homeostatic mechanisms and subcellular distribution have been defined. Biochemical studies have also suggested that stimulation of Gq protein-coupled membrane receptors activates phospholipase C and promotes the hydrolysis of membrane phospholipids into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). IP3 stimulates initial Ca2+ release from the sarcoplasmic reticulum, and is buttressed by Ca2+ influx through voltage-dependent, receptor-operated, transient receptor potential and store-operated channels. In order to prevent large increases in cytosolic Ca2+ concentration ([Ca2+]c), Ca2+ removal mechanisms promote Ca2+ extrusion via the plasmalemmal Ca2+ pump and Na+/Ca2+ exchanger, and Ca2+ uptake by the sarcoplasmic reticulum and mitochondria, and the coordinated activities of these Ca2+ handling mechanisms help to create subplasmalemmal Ca2+ domains. Threshold increases in [Ca2+]c form a Ca2+-calmodulin complex, which activates myosin light chain (MLC) kinase, and causes MLC phosphorylation, actin-myosin interaction, and VSM contraction. Dissociations in the relationships between [Ca2+]c, MLC phosphorylation, and force have suggested additional Ca2+ sensitization mechanisms. DAG activates protein kinase C (PKC) isoforms, which directly or indirectly via mitogen-activated protein kinase phosphorylate the actin-binding proteins calponin and caldesmon and thereby enhance the myofilaments force sensitivity to Ca2+. PKC-mediated phosphorylation of PKC-potentiated phosphatase inhibitor protein-17 (CPI-17), and RhoA-mediated activation of Rho-kinase (ROCK) inhibit MLC phosphatase and in turn increase MLC phosphorylation and VSM contraction. Abnormalities in the Ca2+ handling mechanisms and PKC and ROCK activity have been associated with vascular dysfunction in multiple vascular disorders. Modulators of [Ca2+]c, PKC and ROCK activity could be useful in mitigating the increased vasoconstriction associated with vascular disease.
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Affiliation(s)
- Zhongwei Liu
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Raouf A Khalil
- Vascular Surgery Research Laboratories, Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA.
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Chen YC, Inagaki T, Fujii Y, Schwenke DO, Tsuchimochi H, Edgley AJ, Umetani K, Zhang Y, Kelly DJ, Yoshimoto M, Nagai H, Evans RG, Kuwahira I, Shirai M, Pearson JT. Chronic intermittent hypoxia accelerates coronary microcirculatory dysfunction in insulin-resistant Goto-Kakizaki rats. Am J Physiol Regul Integr Comp Physiol 2016; 311:R426-39. [DOI: 10.1152/ajpregu.00112.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/30/2016] [Indexed: 12/20/2022]
Abstract
Chronic intermittent hypoxia (IH) induces oxidative stress and inflammation, which impair vascular endothelial function. Long-term insulin resistance also leads to endothelial dysfunction. We determined, in vivo, whether the effects of chronic IH and insulin resistance on endothelial function augment each other. Male 12-wk-old Goto-Kakizaki (GK) and Wistar control rats were subjected to normoxia or chronic IH (90-s N2, 5% O2 at nadir, 90-s air, 20 cycles/h, 8 h/day) for 4 wk. Coronary endothelial function was assessed using microangiography with synchrotron radiation. Imaging was performed at baseline, during infusion of acetylcholine (ACh, 5 μg·kg−1·min−1) and then sodium nitroprusside (SNP, 5 μg·kg−1·min−1), after blockade of both nitric oxide (NO) synthase (NOS) with Nω-nitro-l-arginine methyl ester (l-NAME, 50 mg/kg) and cyclooxygenase (COX, meclofenamate, 3 mg/kg), and during subsequent ACh. In GK rats, coronary vasodilatation in response to ACh and SNP was blunted compared with Wistar rats, and responses to ACh were abolished after blockade. In Wistar rats, IH blunted the ability of ACh or SNP to increase the number of visible vessels. In GK rats exposed to IH, neither ACh nor SNP were able to increase visible vessel number or caliber, and blockade resulted in marked vasoconstriction. Our findings indicate that IH augments the deleterious effects of insulin resistance on coronary endothelial function. They appear to increase the dependence of the coronary microcirculation on NO and/or vasodilator prostanoids, and greatly blunt the residual vasodilation in response to ACh after blockade of NOS/COX, presumably mediated by endothelium-derived hyperpolarizing factors.
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Affiliation(s)
- Yi Ching Chen
- Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Tadakatsu Inagaki
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Yutaka Fujii
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Daryl O. Schwenke
- Department of Physiology-Heart Otago, University of Otago, Dunedin, New Zealand
| | - Hirotsugu Tsuchimochi
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Amanda J. Edgley
- Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
- St Vincent's Hospital, University of Melbourne, Melbourne, Australia
| | - Keiji Umetani
- Japan Synchrotron Radiation Research Institute, Harima, Japan
| | - Yuan Zhang
- St Vincent's Hospital, University of Melbourne, Melbourne, Australia
| | - Darren J. Kelly
- St Vincent's Hospital, University of Melbourne, Melbourne, Australia
| | - Misa Yoshimoto
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - Hisashi Nagai
- Departments of Clinical Laboratory Medicine and Forensic Medicine, University of Tokyo, Tokyo, Japan
| | - Roger G. Evans
- Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Ichiro Kuwahira
- Department of Pulmonary Medicine, Tokai University Tokyo Hospital, Tokai University, Tokyo, Japan
| | - Mikiyasu Shirai
- Department of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan
| | - James T. Pearson
- Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
- Monash Biomedical Imaging Facility, Melbourne, Australia; and
- Australian Synchrotron, Melbourne, Australia
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Ringvold HC, Khalil RA. Protein Kinase C as Regulator of Vascular Smooth Muscle Function and Potential Target in Vascular Disorders. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:203-301. [PMID: 28212798 PMCID: PMC5319769 DOI: 10.1016/bs.apha.2016.06.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Vascular smooth muscle (VSM) plays an important role in maintaining vascular tone. In addition to Ca2+-dependent myosin light chain (MLC) phosphorylation, protein kinase C (PKC) is a major regulator of VSM function. PKC is a family of conventional Ca2+-dependent α, β, and γ, novel Ca2+-independent δ, ɛ, θ, and η, and atypical ξ, and ι/λ isoforms. Inactive PKC is mainly cytosolic, and upon activation it undergoes phosphorylation, maturation, and translocation to the surface membrane, the nucleus, endoplasmic reticulum, and other cell organelles; a process facilitated by scaffold proteins such as RACKs. Activated PKC phosphorylates different substrates including ion channels, pumps, and nuclear proteins. PKC also phosphorylates CPI-17 leading to inhibition of MLC phosphatase, increased MLC phosphorylation, and enhanced VSM contraction. PKC could also initiate a cascade of protein kinases leading to phosphorylation of the actin-binding proteins calponin and caldesmon, increased actin-myosin interaction, and VSM contraction. Increased PKC activity has been associated with vascular disorders including ischemia-reperfusion injury, coronary artery disease, hypertension, and diabetic vasculopathy. PKC inhibitors could test the role of PKC in different systems and could reduce PKC hyperactivity in vascular disorders. First-generation PKC inhibitors such as staurosporine and chelerythrine are not very specific. Isoform-specific PKC inhibitors such as ruboxistaurin have been tested in clinical trials. Target delivery of PKC pseudosubstrate inhibitory peptides and PKC siRNA may be useful in localized vascular disease. Further studies of PKC and its role in VSM should help design isoform-specific PKC modulators that are experimentally potent and clinically safe to target PKC in vascular disease.
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Affiliation(s)
- H C Ringvold
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - R A Khalil
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
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Jackson-Weaver O, Osmond JM, Naik JS, Gonzalez Bosc LV, Walker BR, Kanagy NL. Intermittent hypoxia in rats reduces activation of Ca2+ sparks in mesenteric arteries. Am J Physiol Heart Circ Physiol 2015; 309:H1915-22. [PMID: 26408536 DOI: 10.1152/ajpheart.00179.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 09/17/2015] [Indexed: 01/25/2023]
Abstract
Ca(+) sparks are vascular smooth muscle cell (VSMC) Ca(2+)-release events that are mediated by ryanodine receptors (RyR) and promote vasodilation by activating large-conductance Ca(2+)-activated potassium channels and inhibiting myogenic tone. We have previously reported that exposing rats to intermittent hypoxia (IH) to simulate sleep apnea augments myogenic tone in mesenteric arteries through loss of hydrogen sulfide (H2S)-induced dilation. Because we also observed that H2S can increase Ca(2+) spark activity, we hypothesized that loss of H2S after IH exposure reduces Ca(2+) spark activity and that blocking Ca(2+) spark generation reduces H2S-induced dilation. Ca(2+) spark activity was lower in VSMC of arteries from IH compared with sham-exposed rats. Furthermore, depolarizing VSMC by increasing luminal pressure (from 20 to 100 mmHg) or by elevating extracellular [K(+)] increased spark activity in VSMC of arteries from sham rats but had no effect in arteries from IH rats. Inhibiting endogenous H2S production in sham arteries prevented these increases. NaHS or phosphodiesterase inhibition increased spark activity to the same extent in sham and IH arteries. Depolarization-induced increases in Ca(2+) spark activity were due to increased sparks per site, whereas H2S increases in spark activity were due to increased spark sites per cell. Finally, inhibiting Ca(2+) spark activity with ryanodine (10 μM) enhanced myogenic tone in arteries from sham but not IH rats and blocked dilation to exogenous H2S in arteries from both sham and IH rats. Our results suggest that H2S regulates RyR activation and that H2S-induced dilation requires Ca(2+) spark activation. IH exposure decreases endogenous H2S-dependent Ca(2+) spark activation to cause membrane depolarization and enhance myogenic tone in mesenteric arteries.
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Affiliation(s)
- Olan Jackson-Weaver
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, New Mexico
| | - Jessica M Osmond
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, New Mexico
| | - Jay S Naik
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, New Mexico
| | - Laura V Gonzalez Bosc
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, New Mexico
| | - Benjimen R Walker
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, New Mexico
| | - Nancy L Kanagy
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, New Mexico
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Protein Kinase C Isoforms Distinctly Regulate Propofol-induced Endothelium-dependent and Endothelium-independent Vasodilation. J Cardiovasc Pharmacol 2015; 66:276-84. [DOI: 10.1097/fjc.0000000000000275] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Yu J, Ok SH, Kim WH, Cho H, Park J, Shin IW, Lee HK, Chung YK, Choi MJ, Kwon SC, Sohn JT. Dexmedetomidine-Induced Contraction in the Isolated Endothelium-Denuded Rat Aorta Involves PKC-δ-mediated JNK Phosphorylation. Int J Med Sci 2015; 12:727-36. [PMID: 26392810 PMCID: PMC4571550 DOI: 10.7150/ijms.11952] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 08/17/2015] [Indexed: 12/18/2022] Open
Abstract
Vasoconstriction mediated by the highly selective alpha-2 adrenoceptor agonist dexmedetomidine leads to transiently increased blood pressure and severe hypertension. The dexmedetomidine-induced contraction involves the protein kinase C (PKC)-mediated pathway. However, the main PKC isoform involved in the dexmedetomidine-induced contraction remains unknown. The goal of this in vitro study was to examine the specific PKC isoform that contributes to the dexmedetomidine-induced contraction in the isolated rat aorta. The endothelium-denuded rat aorta was suspended for isometric tension recording. Dexmedetomidine dose-response curves were generated in the presence or absence of the following inhibitors: the pan-PKC inhibitor, chelerythrine; the PKC-α and -β inhibitor, Go6976; the PKC-α inhibitor, safingol; the PKC-β inhibitor, ruboxistaurin; the PKC-δ inhibitor, rottlerin; the c-Jun NH2-terminal kinase (JNK) inhibitor, SP600125; and the myosin light chain kinase inhibitor, ML-7 hydrochloride. Western blot analysis was used to examine the effect of rottlerin on dexmedetomidine-induced PKC-δ expression and JNK phosphorylation in rat aortic vascular smooth muscle cells (VSMCs) and to investigate the effect of dexmedetomidine on PKC-δ expression in VSMCs transfected with PKC-δ small interfering RNA (siRNA) or control siRNA. Chelerythrine as well as SP600125 and ML-7 hydrochloride attenuated the dexmedetomidine-induced contraction. Go6976, safingol, and ruboxistaurin had no effect on the dexmedetomidine-induced contraction, whereas rottlerin inhibited the dexmedetomidine-induced contraction. Dexmedetomidine induced PKC-δ expression, whereas rottlerin and PKC-δ siRNA transfection inhibited dexmedetomidine-induced PKC-δ expression. Dexmedetomidine also induced JNK phosphorylation, which was inhibited by rottlerin. Taken together, these results suggest that the dexmedetomidine-induced contraction involves PKC-δ-dependent JNK phosphorylation in the isolated rat aorta.
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Affiliation(s)
- Jongsun Yu
- 1. Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju-si, 52727, Republic of Korea
| | - Seong-Ho Ok
- 1. Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju-si, 52727, Republic of Korea
| | - Won Ho Kim
- 2. Department of Anesthesiology and Pain Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
| | - Hyunhoo Cho
- 3. Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Republic of Korea
| | - Jungchul Park
- 3. Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju, Republic of Korea
| | - Il-Woo Shin
- 1. Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju-si, 52727, Republic of Korea
| | - Heon Keun Lee
- 1. Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju-si, 52727, Republic of Korea
| | - Young-Kyun Chung
- 1. Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju-si, 52727, Republic of Korea
| | - Mun-Jeoung Choi
- 4. Department of Oral and Maxillofacial Surgery, Gyeongsang National University Hospital, Jinju, Republic of Korea
| | - Seong-Chun Kwon
- 5. Department of Physiology, Institute for Clinical and Translational Research, Catholic Kwandong University College of Medicine, Gangneung, 25601, Korea
| | - Ju-Tae Sohn
- 1. Department of Anesthesiology and Pain Medicine, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju-si, 52727, Republic of Korea ; 6. Institute of Health Sciences, Gyeongsang National University, Jinju, Republic of Korea
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Altaf Q, Tahrani AA. Obstructive Sleep Apnea and Diabetic Microvascular Complications. MODULATION OF SLEEP BY OBESITY, DIABETES, AGE, AND DIET 2015:213-224. [DOI: 10.1016/b978-0-12-420168-2.00023-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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12
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Mateika JH, El-Chami M, Shaheen D, Ivers B. Intermittent hypoxia: a low-risk research tool with therapeutic value in humans. J Appl Physiol (1985) 2014; 118:520-32. [PMID: 25549763 DOI: 10.1152/japplphysiol.00564.2014] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Intermittent hypoxia has generally been perceived as a high-risk stimulus, particularly in the field of sleep medicine, because it is thought to initiate detrimental cardiovascular, respiratory, cognitive, and metabolic outcomes. In contrast, the link between intermittent hypoxia and beneficial outcomes has received less attention, perhaps because it is not universally understood that outcome measures following exposure to intermittent hypoxia may be linked to the administered dose. The present review is designed to emphasize the less recognized beneficial outcomes associated with intermittent hypoxia. The review will consider the role intermittent hypoxia has in cardiovascular and autonomic adaptations, respiratory motor plasticity, and cognitive function. Each section will highlight the literature that contributed to the belief that intermittent hypoxia leads primarily to detrimental outcomes. The second segment of each section will consider the possible risks associated with experimentally rather than naturally induced intermittent hypoxia. Finally, the body of literature indicating that intermittent hypoxia initiates primarily beneficial outcomes will be considered. The overarching theme of the review is that the use of intermittent hypoxia in research investigations, coupled with reasonable safeguards, should be encouraged because of the potential benefits linked to the administration of a variety of low-risk intermittent hypoxia protocols.
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Affiliation(s)
- Jason H Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - Mohamad El-Chami
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - David Shaheen
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Blake Ivers
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
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13
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Blesson CS, Chinnathambi V, Hankins GD, Yallampalli C, Sathishkumar K. Prenatal testosterone exposure induces hypertension in adult females via androgen receptor-dependent protein kinase Cδ-mediated mechanism. Hypertension 2014; 65:683-690. [PMID: 25489059 DOI: 10.1161/hypertensionaha.114.04521] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Prenatal exposure to excess testosterone induces hyperandrogenism in adult females and predisposes them to hypertension. We tested whether androgens induce hypertension through transcriptional regulation and signaling of protein kinase C (PKC) in the mesenteric arteries. Pregnant Sprague-Dawley rats were injected with vehicle or testosterone propionate (0.5 mg/kg per day from gestation days 15 to 19, SC) and their 6-month-old adult female offspring were examined. Plasma testosterone levels (0.84±0.04 versus 0.42±0.09 ng/mL) and blood pressures (111.6±1.3 versus 104.5±2.4 mm Hg) were significantly higher in prenatal testosterone-exposed rats compared with controls. This was accompanied with enhanced expression of PKCδ mRNA (1.5-fold) and protein (1.7-fold) in the mesenteric arteries of prenatal testosterone-exposed rats. In addition, mesenteric artery contractile responses to PKC activator, phorbol-12,13-dibutyrate, was significantly greater in prenatal testosterone-exposed rats. Treatment with androgen receptor antagonist flutamide (10 mg/kg, SC, BID for 10 days) significantly attenuated hypertension, PKCδ expression, and the exaggerated vasoconstriction in prenatal testosterone-exposed rats. In vitro exposure of testosterone to cultured mesenteric artery smooth muscle cells dose dependently upregulated PKCδ expression. Analysis of PKCδ gene revealed a putative androgen responsive element in the promoter upstream to the transcription start site and an enhancer element in intron-1. Chromatin immunoprecipitation assays showed that androgen receptors bind to these elements in response to testosterone stimulation. Furthermore, luciferase reporter assays showed that the enhancer element is highly responsive to androgens and treatment with flutamide reverses reporter activity. Our studies identified a novel androgen-mediated mechanism for the control of PKCδ expression via transcriptional regulation that controls vasoconstriction and blood pressure.
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Affiliation(s)
- Chellakkan S Blesson
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX 77030
| | - Vijayakumar Chinnathambi
- Division of Reproductive Endocrinology Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX 77555
| | - Gary D Hankins
- Division of Reproductive Endocrinology Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX 77555
| | - Chandra Yallampalli
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX 77030
| | - Kunju Sathishkumar
- Division of Reproductive Endocrinology Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX 77555
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Abstract
PURPOSE OF REVIEW The relationship between obstructive sleep apnoea (OSA) and dysglycaemia is well established. However, uncertainty remains as to the extent that obesity mediates this relationship. The impact of OSA treatment on glucose metabolism and the consequences of having OSA in patients with diabetes is unclear. This review aims to summarize the latest evidence regarding the links between OSA and dysglycaemia. RECENT FINDINGS OSA is associated with insulin resistance in lean individuals and predicts insulin resistance worsening longitudinally. Continuous positive airway pressure (CPAP) lowers insulin resistance in CPAP-compliant patients. OSA is associated with impaired β-cell function. In patients with type 2 diabetes (T2D), the association between OSA and glycosylated haemoglobin (HbA1c) is related to nocturnal hypoxaemia. Apnoea hypopnoea index (AHI) during rapid eye movement (REM) (not non-REM) sleep is associated with HbA1c. In-laboratory, supervised CPAP improves glycaemia. OSA is associated with and predicts the progression of some diabetic vascular complications. Intensive lifestyle intervention in patients with T2D improves OSA independent of weight loss. SUMMARY OSA is associated with insulin resistance and β-cell dysfunction independent of obesity. OSA is associated with HbA1c and vascular complications in patients with T2D. CPAP might improve insulin resistance and glycaemic measures. Lifestyle intervention has a significant impact on AHI in patients with T2D.
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15
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Almendros I, Wang Y, Gozal D. The polymorphic and contradictory aspects of intermittent hypoxia. Am J Physiol Lung Cell Mol Physiol 2014; 307:L129-40. [PMID: 24838748 DOI: 10.1152/ajplung.00089.2014] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Intermittent hypoxia (IH) has been extensively studied during the last decade, primarily as a surrogate model of sleep apnea. However, IH is a much more pervasive phenomenon in human disease, is viewed as a potential therapeutic approach, and has also been used in other disciplines, such as in competitive sports. In this context, adverse outcomes involving cardiovascular, cognitive, metabolic, and cancer problems have emerged in obstructive sleep apnea-based studies, whereas beneficial effects of IH have also been identified. Those a priori contradictory findings may not be as contradictory as initially thought. Indeed, the opposite outcomes triggered by IH can be explained by the specific characteristics of the large diversity of IH patterns applied in each study. The balance between benefits and injury appears to primarily depend on the ability of the organism to respond and activate adaptive mechanisms to IH. In this context, the adaptive or maladaptive responses can be generally predicted by the frequency, severity, and duration of IH. However, the presence of underlying conditions such as hypertension or obesity, as well as age, sex, or genotypic variance, may be important factors tilting the balance between an appropriate homeostatic response and decompensation. Here, the two possible facets of IH as derived from human and experimental animal settings will be reviewed.
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Affiliation(s)
- Isaac Almendros
- Department of Pediatrics, Comer Children's Hospital, Pritzker School of Medicine, The University of Chicago, Chicago, Illinois
| | - Yang Wang
- Department of Pediatrics, Comer Children's Hospital, Pritzker School of Medicine, The University of Chicago, Chicago, Illinois
| | - David Gozal
- Department of Pediatrics, Comer Children's Hospital, Pritzker School of Medicine, The University of Chicago, Chicago, Illinois
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Tahrani AA, Ali A. Obstructive Sleep Apnoea and Type 2 Diabetes. EUROPEAN ENDOCRINOLOGY 2014; 10:43-50. [PMID: 29872463 DOI: 10.17925/ee.2014.10.01.43] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 03/07/2014] [Indexed: 12/20/2022]
Abstract
With the growing prevalence of obesity, the burden of type 2 diabetes is increasing. Obstructive sleep apnoea (OSA) is a very common medical condition that is associated with increased risk of cardiovascular disease and mortality. Obesity is a common risk factor for OSA and type 2 diabetes and hence it is not surprising that OSA and type 2 diabetes are interlinked. OSA has been shown to be an independent risk factor for the development of incident pre-diabetes/type 2 diabetes. OSA is also associated with worse glycaemic control and vascular disease in patients with type 2 diabetes. However, evidence for the benefits of OSA treatment in patients with type 2 diabetes is still lacking. The aim of this article is to provide an overview of OSA, the relationships between OSA and dysglycaemia and the impact of OSA in patients with type 2 diabetes, highlighting recent advances in the field.
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Affiliation(s)
- Abd A Tahrani
- NIHR Clinician Scientist, Centre of Endocrinology, Diabetes and Metabolism, University of Birmingham and Honorary Consultant Physician, Department of Diabetes and Endocrinology, Heart of England NHS Foundation Trust, Birmingham, UK
| | - Asad Ali
- Consultant Respiratory Physician, Department of Respiratory Medicine, University Hospital of Coventry and Warwickshire, Coventry, UK
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Tahrani AA, Ali A, Raymond NT, Begum S, Dubb K, Altaf QA, Piya MK, Barnett AH, Stevens MJ. Obstructive sleep apnea and diabetic nephropathy: a cohort study. Diabetes Care 2013; 36:3718-25. [PMID: 24062320 PMCID: PMC3816897 DOI: 10.2337/dc13-0450] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Diabetic nephropathy (DN) is a leading cause of end-stage renal disease (ESRD). Obstructive sleep apnea (OSA) is common in type 2 diabetes and increases oxidative stress. Hence, OSA could promote the development and progression of DN. RESEARCH DESIGN AND METHODS This was a cohort study in adults with type 2 diabetes. Patients with known OSA or ESRD were excluded. DN was defined as the presence of albuminuria or an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. DN progression was based on eGFR measurements. OSA was defined as apnea hypopnea index (AHI) ≥5 events/h. Serum nitrotyrosine abundance (a marker of nitrosative stress) was measured by ELISA. RESULTS A total of 224 patients were included. OSA and DN prevalence was 64.3 and 40.2, respectively. DN prevalence was higher in patients with OSA (OSA+) compared with those without OSA (OSA-) (49.3% vs. 23.8%, P < 0.001). After adjustment, OSA (odds ratio 2.64 [95% CI 1.13-6.16], P = 0.02) remained independently associated with DN. After an average follow-up of 2.5 (0.7) years, eGFR decline was greater in OSA+ compared with OSA- patients (median -6.8% [interquartile range -16.1 to 2.2] vs. -1.6% [-7.7 to 5.3%], P = 0.002). After adjusting, both baseline OSA (B = -3.8, P = 0.044) and AHI (B = -4.6, P = 0.02) remained independent predictors of study-end eGFR. Baseline serum nitrotyrosine abundance (B = -0.24, P = 0.015) was an independent predictor of study-end eGFR after adjustment. CONCLUSIONS OSA is independently associated with DN in type 2 diabetes. eGFR declined faster in patients with OSA. Nitrosative stress may provide a pathogenetic link between OSA and DN. Interventional studies assessing the impact of OSA treatment on DN are needed.
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18
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Wang Z, Si LY. Hypoxia-inducible factor-1α and vascular endothelial growth factor in the cardioprotective effects of intermittent hypoxia in rats. Ups J Med Sci 2013; 118:65-74. [PMID: 23441597 PMCID: PMC3633332 DOI: 10.3109/03009734.2013.766914] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 12/11/2012] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE This study investigated the effects of short-term intermittent hypoxia (IH) preconditioning on cardiac structure and function in rats and the influence of ischemia reperfusion (I/R) injury. Special attention was then paid to the involvement of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). METHODS Wistar rats were given IH treatment for 1, 7, 14, or 28 days. Some of them were thereafter subject to myocardial infarction surgery. Right ventricle systolic pressure (RVSP), myocardial capillary density (CD), and mRNA/protein expression of HIF-1α, VEGF, and Bcl-2 in rat myocardial tissue were determined. Apoptotic cell number was determined by TUNEL staining, and concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured. RESULTS IH treatment for 1, 7, 14, and 28 days reduced the myocardial infarction size, whereas IH for 28 days increased the RVSP, ratio of right to left ventricle weight (RV/LV+S), and CD. IH up-regulated the mRNA and protein levels of HIF-1α, VEGF, and Bcl-2 both under normal and I/R conditions. The induced expression of HIF-1α and VEGF by IH reached a peak after 7 days of treatment. Moreover, IH for 28 days induced cardiomyocyte apoptosis, whereas prior treatment with IH for 1, 7, 14, and 28 days all markedly attenuated the apoptosis effected by the subsequent I/R injury. IH also decreased the concentrations of MDA but increased those of SOD in myocardial tissue of both in normal rats and following I/R. CONCLUSIONS The present study demonstrates that short-term IH protects the heart from I/R injury through inhibiting apoptosis and oxidative stress. The up-regulation of HIF-1α and VEGF by short-term IH may participate in the cardioprotective effect of IH.
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Affiliation(s)
- Zhang Wang
- Department of Geriatrics, The First Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Liang-Yi Si
- Department of Geriatrics, The First Affiliated Hospital, Third Military Medical University, Chongqing, China
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19
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Wang Z, Li AY, Guo QH, Zhang JP, An Q, Guo YJ, Chu L, Weiss JW, Ji ES. Effects of cyclic intermittent hypoxia on ET-1 responsiveness and endothelial dysfunction of pulmonary arteries in rats. PLoS One 2013; 8:e58078. [PMID: 23555567 PMCID: PMC3589442 DOI: 10.1371/journal.pone.0058078] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 01/31/2013] [Indexed: 11/26/2022] Open
Abstract
Obstructive sleep apnoea (OSA) is a risk factor for cardiovascular disorders and in some cases is complication of pulmonary hypertension. We simulated OSA by exposing rats to cyclic intermittent hypoxia (CIH) to investigate its effect on pulmonary vascular endothelial dysfunction. Sprague-Dawley Rats were exposed to CIH (FiO2 9% for 1 min, repeated every 2 min for 8 h/day, 7 days/wk for 3 wk), and the pulmonary arteries of normoxia and CIH treated rats were analyzed for expression of endothelin-1 (ET-1) and ET receptors by histological, immunohistochemical, RT-PCR and Western Blot analyses, as well as for contractility in response to ET-1. In the pulmonary arteries, ET-1 expression was increased, and ET-1 more potently elicited constriction of the pulmonary artery in CIH rats than in normoxic rats. Exposure to CIH induced marked endothelial cell damage associated with a functional decrease of endothelium-dependent vasodilatation in the pulmonary artery. Compared with normoxic rats, ETA receptor expression was increased in smooth muscle cells of the CIH rats, while the expression of ETB receptors was decreased in endothelial cells. These results demonstrated endothelium-dependent vasodilation was impaired and the vasoconstrictor responsiveness increased by CIH. The increased responsiveness to ET-1 induced by intermittent hypoxia in pulmonary arteries of rats was due to increased expression of ETA receptors predominantly, meanwhile, decreased expression of ETB receptors in the endothelium may also participate in it.
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MESH Headings
- Animals
- Endothelin-1/biosynthesis
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Gene Expression Regulation
- Hypertension, Pulmonary/etiology
- Hypertension, Pulmonary/metabolism
- Hypertension, Pulmonary/pathology
- Hypertension, Pulmonary/physiopathology
- Hypoxia/complications
- Hypoxia/metabolism
- Hypoxia/pathology
- Hypoxia/physiopathology
- Male
- Pulmonary Artery/metabolism
- Pulmonary Artery/pathology
- Pulmonary Artery/physiopathology
- Rats
- Rats, Sprague-Dawley
- Receptors, Endothelin/biosynthesis
- Sleep Apnea, Obstructive/complications
- Sleep Apnea, Obstructive/metabolism
- Sleep Apnea, Obstructive/pathology
- Sleep Apnea, Obstructive/physiopathology
- Vasoconstriction
- Vasodilation
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Affiliation(s)
- Zhuo Wang
- Department of Physiology, Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Ai-Ying Li
- Department of Biochemistry, Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Qiu-Hong Guo
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Jian-Ping Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Qi An
- Department of Physiology, Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Ya-jing Guo
- Department of Physiology, Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - Li Chu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
| | - J. Woodrow Weiss
- Division of Pulmonary, Critical Care, and Sleep Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- * E-mail: (ESJ); (JWW)
| | - En-Sheng Ji
- Department of Physiology, Hebei Medical University, Shijiazhuang, Hebei, People's Republic of China
- * E-mail: (ESJ); (JWW)
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Webster BR, Osmond JM, Paredes DA, DeLeon XA, Jackson-Weaver O, Walker BR, Kanagy NL. Phosphoinositide-dependent kinase-1 and protein kinase Cδ contribute to endothelin-1 constriction and elevated blood pressure in intermittent hypoxia. J Pharmacol Exp Ther 2012; 344:68-76. [PMID: 23093023 DOI: 10.1124/jpet.112.195412] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Obstructive sleep apnea (OSA) is associated with cardiovascular complications including hypertension. Previous findings from our laboratory indicate that exposure to intermittent hypoxia (IH), to mimic sleep apnea, increases blood pressure in rats. IH also increases endothelin-1 (ET-1) constrictor sensitivity in a protein kinase C (PKC) δ-dependent manner in mesenteric arteries. Because phosphoinositide-dependent kinase-1 (PDK-1) regulates PKCδ activity, we hypothesized that PDK-1 contributes to the augmented ET-1 constrictor sensitivity and elevated blood pressure following IH. Male Sprague-Dawley rats were exposed to either sham or IH (cycles between 21% O(2)/0% CO(2) and 5% O(2)/5% CO(2)) conditions for 7 h/day for 14 or 21 days. The contribution of PKCδ and PDK-1 to ET-1-mediated vasoconstriction was assessed in mesenteric arteries using pharmacological inhibitors. Constrictor sensitivity to ET-1 was enhanced in arteries from IH-exposed rats. Inhibition of PKCδ or PDK-1 blunted ET-1 constriction in arteries from IH but not sham group rats. Western analysis revealed similar levels of total and phosphorylated PDK-1 in arteries from sham and IH group rats but decreased protein-protein interaction between PKCδ and PDK-1 in arteries from IH- compared with sham-exposed rats. Blood pressure was increased in rats exposed to IH, and treatment with the PDK-1 inhibitor OSU-03012 [2-amino-N-{4-[5-(2-phenanthrenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]-phenyl}-acetamide] (33 mg/day) lowered blood pressure in IH but not sham group rats. Our results suggest that exposure to IH unmasks a role for PDK-1 in regulating ET-1 constrictor sensitivity and blood pressure that is not present under normal conditions. These novel findings suggest that PDK-1 may be a uniquely effective antihypertensive therapy for OSA patients.
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Affiliation(s)
- Bradley R Webster
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM 87131, USA
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Tahrani AA, Ali A, Raymond NT, Begum S, Dubb K, Mughal S, Jose B, Piya MK, Barnett AH, Stevens MJ. Obstructive sleep apnea and diabetic neuropathy: a novel association in patients with type 2 diabetes. Am J Respir Crit Care Med 2012; 186:434-41. [PMID: 22723291 DOI: 10.1164/rccm.201112-2135oc] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
RATIONALE Diabetic peripheral neuropathy is common and causes significant morbidity. Obstructive sleep apnea (OSA) is also common in patients with type 2 diabetes. Because OSA is associated with inflammation and oxidative stress, we hypothesized that OSA is associated with peripheral neuropathy in type 2 diabetes. OBJECTIVES To assess the relationship between OSA and peripheral neuropathy in patients with type 2 diabetes. METHODS A cross-sectional study of adults with type 2 diabetes recruited randomly from the diabetes clinic of two UK hospitals. MEASUREMENTS AND MAIN RESULTS Peripheral neuropathy was diagnosed using the Michigan Neuropathy Screening Instrument. OSA (apnea-hypopnea index ≥ 5 events/h) was assessed using home-based, multichannel respiratory monitoring. Serum nitrotyrosine was measured by ELISA, lipid peroxide by spectrophotometer, and microvascular function by laser speckle contrast imaging. Two hundred thirty-four patients (mean [SD] age, 57 [12] yr) were analyzed. OSA prevalence was 65% (median apnea-hypopnea index, 7.2; range, 0-93), 40% of which were moderate to severe. Neuropathy prevalence was higher in patients with OSA than those without (60% vs. 27%, P < 0.001). After adjustment for possible confounders, OSA remained independently associated with diabetic neuropathy (odds ratio, 2.82; 95% confidence interval, 1.44-5.52; P = 0.0034). Nitrotyrosine and lipid peroxide levels (n = 102, 74 with OSA) were higher in OSA and correlated with hypoxemia severity. Cutaneous microvascular function (n = 71, 47 with OSA) was impaired in OSA. CONCLUSIONS We describe a novel independent association between diabetic peripheral neuropathy and OSA. We identified increased nitrosative/oxidative stress and impaired microvascular regulation as potential mechanisms. Prospective and interventional studies are needed to assess the impact of OSA and its treatment on peripheral neuropathy development and progression in patients with type 2 diabetes.
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Affiliation(s)
- Abd A Tahrani
- Centre of Endocrinology, Diabetes, and Metabolism, University of Birmingham, Birmingham, United Kingdom.
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Ishida K, Matsumoto T, Taguchi K, Kamata K, Kobayashi T. Protein kinase C delta contributes to increase in EP3 agonist-induced contraction in mesenteric arteries from type 2 diabetic Goto-Kakizaki rats. Pflugers Arch 2012; 463:593-602. [PMID: 22371141 DOI: 10.1007/s00424-012-1088-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 02/02/2012] [Accepted: 02/16/2012] [Indexed: 01/26/2023]
Abstract
Prostaglandin E(2) (PGE(2)), an important and ubiquitously present vasoactive eicosanoid, may either constrict or dilate systemic vascular beds. However, little is known about the vascular contractile responsiveness to and signaling pathways for PGE(2) at the chronic stage of type 2 diabetes. We hypothesized that PGE(2)-induced arterial contraction is augmented in type 2 diabetic Goto-Kakizaki (GK) rats via the protein kinase Cδ (PKCδ) pathway. Here, we investigated the vasoconstrictor effects of PGE(2) and of sulprostone (EP1-/EP3-receptor agonist) in rings cut from superior mesenteric arteries isolated from GK rats (37-44 weeks old). In arteries from GK rats (vs. those from age-matched Wistar rats), examined in the presence of a nitric oxide synthase inhibitor: 1) the PGE(2)- and sulprostone-induced vasocontractions (which were not blocked by the selective EP1 receptor antagonist sc19220) were enhanced, and these enhancements were suppressed by rottlerin (selective PKCδ inhibitor) but not by Gö6976 (selective PKCα/β inhibitor); 2) the sulprostone-stimulated phosphorylation of PKCδ (at Thr(505)), which yields an active form, was increased and 3) sulprostone-stimulated caldesmon phosphorylations, which are related to isometric force generation in smooth muscle, were increased. The protein expression of EP3 receptor in superior mesenteric arteries was similar between the two groups of rats. Our data suggest that the diabetes-related enhancement of EP3 receptor-mediated vasocontraction results from activation of the PKCδ pathway. Alterations in EP3 receptor-mediated vasocontraction may be important factors in the pathophysiological influences over arterial tone that are present in diabetic states.
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Affiliation(s)
- Keiko Ishida
- Department of Physiology and Morphology, Institute of Medicinal Chemistry, Hoshi University, Shinagawa-ku, Tokyo, Japan
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Meyer MR, Field AS, Kanagy NL, Barton M, Prossnitz ER. GPER regulates endothelin-dependent vascular tone and intracellular calcium. Life Sci 2012; 91:623-7. [PMID: 22326502 DOI: 10.1016/j.lfs.2012.01.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 01/17/2012] [Accepted: 01/19/2012] [Indexed: 12/29/2022]
Abstract
AIMS An increase in intracellular vascular smooth muscle cell calcium concentration (VSMC [Ca(2+)](i)) is essential for endothelin-1 (ET-1)-induced vasoconstriction. Based on previous findings that activation of the G protein-coupled estrogen receptor (GPER) inhibits vasoconstriction in response to ET-1 and regulates [Ca(2+)](i) in cultured VSMC, we investigated whether endogenous GPER regulates ET-1-induced changes in VSMC [Ca(2+)](i) and constriction of intact arteries. MAIN METHODS Pressurized carotid arteries of GPER-deficient (GPER(0)) and wildtype (WT) mice were loaded with the calcium indicator fura 2-AM. Arteries were stimulated with the GPER-selective agonist G-1 or solvent followed by exposure to ET-1. Changes in arterial diameter and VSMC [Ca(2+)](i) were recorded simultaneously. Vascular gene expression levels of ET(A) and ET(B) receptors were determined by qPCR. KEY FINDINGS ET-1-dependent vasoconstriction was increased in arteries from GPER(0) compared to arteries from WT mice. Despite the more potent vasoconstriction to ET-1, GPER deficiency was associated with a marked reduction in the ET-1-stimulated VSMC [Ca(2+)](i) increase, suggesting an increase in myofilament force sensitivity to [Ca(2+)](i). Activation of GPER by G-1 had no effect on vasoconstriction or VSMC [Ca(2+)](i) responses to ET-1, and expression levels of ET(A) or ET(B) receptor were unaffected by GPER deficiency. SIGNIFICANCE These results demonstrate that endogenous GPER inhibits ET-1-induced vasoconstriction, an effect that may be associated with reduced VSMC Ca(2+) sensitivity. This represents a potential mechanism through which GPER could contribute to protective effects of endogenous estrogen in the cardiovascular system.
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Affiliation(s)
- Matthias R Meyer
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
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Dysfunctional nucleus tractus solitarius: its crucial role in promoting neuropathogenetic cascade of Alzheimer's dementia--a novel hypothesis. Neurochem Res 2012; 37:846-68. [PMID: 22219130 DOI: 10.1007/s11064-011-0680-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/16/2011] [Accepted: 12/15/2011] [Indexed: 12/22/2022]
Abstract
The pathophysiological mechanism(s) underlying Alzheimer's disease (AD) still remain unclear, and no disease-modifying or prophylactic therapies are currently available. Unraveling the fundamental neuropathogenesis of AD is an important challenge. Several studies on AD have suggested lesions in a number of CNS areas including the basal forebrain, hippocampus, entorhinal cortex, amygdale/insula, and the locus coeruleus. However, plausible unifying studies on the upstream factors that involve these heterogeneous regions and herald the onset of AD pathogenesis are not available. The current article presents a novel nucleus tractus solitarius (NTS) vector hypothesis that underpins several disparate biological mechanisms and neural circuits, and identifies relevant hallmarks of major presumptive causative factor(s) linked to the NTS, in older/aging individuals. Aging, obesity, infection, sleep apnea, smoking, neuropsychological states, and hypothermia-all activate inflammatory cytokines and oxidative stress. The synergistic impact of systemic proinflammatory mediators activates microglia and promotes neuroinflammation. Acutely, the innate immune response is protective defending against pathogens/toxins; however, when chronic, it causes neuroinflammation and neuronal dysfunction, particularly in brainstem and neocortex. The NTS in the brainstem is an essential multiple signaling hub, and an extremely important central integration site of baroreceptor, chemoreceptor, and a multitude of sensory afferents from gustatory, gastrointestinal, cardiac, pulmonary, and upper airway systems. Owing to persistent neuroinflammation, the dysfunctional NTS exerts deleterious impact on nucleus ambiguus, dorsal motor nucleus of vagus, hypoglossal, parabrachial, locus coeruleus and many key nuclei in the brainstem, and the hippocampus, entorhinal cortex, prefrontal cortex, amygdala, insula, and basal forebrain in the neocortex. The neuronal and synaptic dysfunction emanating from the inflamed NTS may affect its interconnected pathways impacting almost the entire CNS--which is already primed by neuroinflammation, thus promoting cognitive and neuropsychiatric symptoms. The upstream factors discussed here may underpin the neuropathopgenesis of AD. AD pathology is multifactorial; the current perspective underscores the value of attenuating disparate upstream factors--in conjunction with anticholinesterase, anti-inflammatory, immunosuppressive, and anti-oxidant pharmacotherapy. Amelioration of the NTS pathology may be of central importance in countering the neuropathological cascade of AD. The NTS, therefore, may be a potential target of novel therapeutic strategies.
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Zamarrón C, Riveiro A, Gude F. Circulating levels of vascular endothelial markers in obstructive sleep apnoea syndrome. Effects of nasal continuous positive airway pressure. Arch Med Sci 2011; 7:1023-8. [PMID: 22328886 PMCID: PMC3264995 DOI: 10.5114/aoms.2011.26615] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 05/25/2011] [Accepted: 06/19/2011] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION Obstructive sleep apnoea syndrome (OSAS) is an important risk factor in cardiovascular disorders. Although the exact mechanism remains to be elucidated, the endothelial dysfunction process seems to be implicated. MATERIAL AND METHODS In order to test this hypothesis, blood circulating levels of endothelial markers were measured at baseline and 1 year after treatment with continuous positive airway pressure (CPAP). We studied 37 males using polysomnography: 20 subjects with OSAS and a 17-subject control group. An OSAS-validated sleep questionnaire covering the most important cardiovascular risk factors was applied to all subjects. Furthermore, patients received a complete general physical examination and biochemistry test with lipid profile. The specific markers measured were intercellular cell adhesion molecule-1 (ICAM-1), E-selectin, endothelin-1, von Willebrand factor (vWF) and plasminogen activator inhibitor-1 (PAI-1). RESULTS Obstructive sleep apnoea syndrome patients presented higher circulating levels of ICAM-1, endothelin-1 and PAI-1 than the control group. On the other hand, no differences were found in E-selectin and vWF. After 1 year of CPAP treatment, there was a significant decrease in circulating levels of ICAM-1 and PAI-1. On the other hand, no differences were found in endothelin-1, E-selectin and vWF. CONCLUSIONS Obstructive sleep apnoea syndrome is associated with elevated levels of ICAM-1 and PAI-1 and these levels normalize after treatment with CPAP.
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Affiliation(s)
- Carlos Zamarrón
- Pulmonary Division, Hospital Clínico Universitario, Santiago de Compostela, Spain
| | - Alberto Riveiro
- Division of Respiratory Medicine, Department of Biochemistry, Hospital Clínico Universitario, Santiago de Compostela, Spain
| | - Francisco Gude
- Clinical Epidemiological Research Unit, Hospital Clínico Universitario, Santiago de Compostela, Spain
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Snow JB, Gonzalez Bosc LV, Kanagy NL, Walker BR, Resta TC. Role for PKCβ in enhanced endothelin-1-induced pulmonary vasoconstrictor reactivity following intermittent hypoxia. Am J Physiol Lung Cell Mol Physiol 2011; 301:L745-54. [PMID: 21803871 DOI: 10.1152/ajplung.00020.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Intermittent hypoxia (IH) resulting from sleep apnea causes both systemic and pulmonary hypertension. Enhanced endothelin-1 (ET-1)-induced vasoconstrictor reactivity is thought to play a central role in the systemic hypertensive response to IH. However, whether IH similarly increases pulmonary vasoreactivity and the signaling mechanisms involved are unknown. The objective of the present study was to test the hypothesis that IH augments ET-1-induced pulmonary vasoconstrictor reactivity through a PKCβ-dependent signaling pathway. Responses to ET-1 were assessed in endothelium-disrupted, pressurized pulmonary arteries (∼150 μm inner diameter) from eucapnic-IH [(E-IH) 3 min cycles, 5% O(2)-5% CO(2)/air flush, 7 h/day; 4 wk] and sham (air-cycled) rats. Arteries were loaded with fura-2 AM to monitor vascular smooth muscle (VSM) intracellular Ca(2+) concentration ([Ca(2+)](i)). E-IH increased vasoconstrictor reactivity without altering Ca(2+) responses, suggestive of myofilament Ca(2+) sensitization. Consistent with our hypothesis, inhibitors of both PKCα/β (myr-PKC) and PKCβ (LY-333-531) selectively decreased vasoconstriction to ET-1 in arteries from E-IH rats and normalized responses between groups, whereas Rho kinase (fasudil) and PKCδ (rottlerin) inhibition were without effect. Although E-IH did not alter arterial PKCα/β mRNA or protein expression, E-IH increased basal PKCβI/II membrane localization and caused ET-1-induced translocation of these isoforms away from the membrane fraction. We conclude that E-IH augments pulmonary vasoconstrictor reactivity to ET-1 through a novel PKCβ-dependent mechanism that is independent of altered PKC expression. These findings provide new insights into signaling mechanisms that contribute to vasoconstriction in the hypertensive pulmonary circulation.
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Affiliation(s)
- Jessica B Snow
- Dept. of Cell Biology and Physiology, Univ. of New Mexico Health Sciences Center, MSC 08-4750, 1 Univ. of New Mexico, Albuquerque, NM 87131-0001, USA.
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Jackson-Weaver O, Paredes DA, Gonzalez Bosc LV, Walker BR, Kanagy NL. Intermittent hypoxia in rats increases myogenic tone through loss of hydrogen sulfide activation of large-conductance Ca(2+)-activated potassium channels. Circ Res 2011; 108:1439-47. [PMID: 21512160 DOI: 10.1161/circresaha.110.228999] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
RATIONALE Myogenic tone, an important regulator of vascular resistance, is dependent on vascular smooth muscle (VSM) depolarization, can be modulated by endothelial factors, and is increased in several models of hypertension. Intermittent hypoxia (IH) elevates blood pressure and causes endothelial dysfunction. Hydrogen sulfide (H(2)S), a recently described endothelium-derived vasodilator, is produced by the enzyme cystathionine γ-lyase (CSE) and acts by hyperpolarizing VSM. OBJECTIVE Determine whether IH decreases endothelial H(2)S production to increase myogenic tone in small mesenteric arteries. METHODS AND RESULTS Myogenic tone was greater in mesenteric arteries from IH than sham control rat arteries, and VSM membrane potential was depolarized in IH in comparison with sham arteries. Endothelium inactivation or scavenging of H(2)S enhanced myogenic tone in sham arteries to the level of IH. Inhibiting CSE also enhanced myogenic tone and depolarized VSM in sham but not IH arteries. Similar results were seen in cerebral arteries. Exogenous H(2)S dilated and hyperpolarized sham and IH arteries, and this dilation was blocked by iberiotoxin, paxilline, and KCl preconstriction but not glibenclamide or 3-isobutyl-1-methylxanthine. Iberiotoxin enhanced myogenic tone in both groups but more in sham than IH. CSE immunofluorescence was less in the endothelium of IH than in sham mesenteric arteries. Endogenouse H(2)S dilation was reduced in IH arteries. CONCLUSIONS IH appears to decrease endothelial CSE expression to reduce H(2)S production, depolarize VSM, and enhance myogenic tone. H(2)S dilatation and hyperpolarization of VSM in small mesenteric arteries requires BK(Ca) channels.
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Affiliation(s)
- Olan Jackson-Weaver
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, NM 87131, USA
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Lima VV, Giachini FR, Hardy DM, Webb RC, Tostes RC. O-GlcNAcylation: a novel pathway contributing to the effects of endothelin in the vasculature. Am J Physiol Regul Integr Comp Physiol 2010; 300:R236-50. [PMID: 21068200 DOI: 10.1152/ajpregu.00230.2010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Glycosylation with O-linked β-N-acetylglucosamine (O-GlcNAc) or O-GlcNAcylation on serine and threonine residues of nuclear and cytoplasmic proteins is a posttranslational modification that alters the function of numerous proteins important in vascular function, including kinases, phosphatases, transcription factors, and cytoskeletal proteins. O-GlcNAcylation is an innovative way to think about vascular signaling events both in physiological conditions and in disease states. This posttranslational modification interferes with vascular processes, mainly vascular reactivity, in conditions where endothelin-1 (ET-1) levels are augmented (e.g. salt-sensitive hypertension, ischemia/reperfusion, and stroke). ET-1 plays a crucial role in the vascular function of most organ systems, both in physiological and pathophysiological conditions. Recognition of ET-1 by the ET(A) and ET(B) receptors activates intracellular signaling pathways and cascades that result in rapid and long-term alterations in vascular activity and function. Components of these ET-1-activated signaling pathways (e.g., mitogen-activated protein kinases, protein kinase C, RhoA/Rho kinase) are also targets for O-GlcNAcylation. Recent experimental evidence suggests that ET-1 directly activates O-GlcNAcylation, and this posttranslational modification mediates important vascular effects of the peptide. This review focuses on ET-1-activated signaling pathways that can be modified by O-GlcNAcylation. A brief description of the O-GlcNAcylation biology is presented, and its role on vascular function is addressed. ET-1-induced O-GlcNAcylation and its implications for vascular function are then discussed. Finally, the interplay between O-GlcNAcylation and O-phosphorylation is addressed.
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Affiliation(s)
- Victor V Lima
- Department of Physiology, Medical College of Georgia, Augusta, Georgia, USA
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Allahdadi KJ, Hannan JL, Tostes RC, Webb RC. Endothelin-1 induces contraction of female rat internal pudendal and clitoral arteries through ET(A) receptor and rho-kinase activation. J Sex Med 2010; 7:2096-2103. [PMID: 20412427 PMCID: PMC3061306 DOI: 10.1111/j.1743-6109.2010.01816.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
INTRODUCTION Endothelin-1 (ET-1), a potent vasoconstrictor peptide, acts mainly through the Gprotein-coupled ET(A) receptor (ET(A)R). Increased vascular ET-1 production and constrictor sensitivity have been observed in various cardiovascular diseases, including hypertension, as well as erectile dysfunction. The internal pudendal artery (IPA) supplies blood to the vagina and clitoris. Inadequate blood flow through the IPA may lead to insufficient vaginal engorgement and clitoral tumescence. AIM Characterize the effects of ET-1 on the IPA and clitoral artery (CA). METHODS IPA and CA from female Sprague Dawley rats (225-250 g) were mounted in myograph chambers. Arterial segments were submitted to increasing concentrations of ET-1 (10-10-10-6 M). Segments were incubated with the ET(A)R antagonist, atrasentan (10-8 M) or the Rho-kinase inhibitor, Y-27632 (10-6 M) 30 minutes prior to agonist exposure. All E(max) values are expressed as % KCl-induced maximal contraction. ET(A)R, RhoA, and Rho-kinase expression from IPA was evaluated by Western blot. mRNA of preproET-1, ET(A)R, ET(B)R, RhoA, and Rho-kinase were measured by real time PCR. MAIN OUTCOME MEASURES ET-1 constrictor sensitivity in IPA and CA, protein expression and messenger RNA levels of ET-1-mediated constriction components. RESULTS ET-1 concentration-dependently contracted IPA (% Contraction and pD2, respectively: 156 ± 18, 8.2 ± 0.1) and CA (163 ± 12, 8.8 ± 0.08), while ET(A)R antagonism reduced ET-1-mediated contraction (IPA: 104 ± 23, 6.4 ± 0.2; CA: 112 ± 17, 6.6 ± 0.08). Pretreatment with Y-27632 significantly shifted ET-1 pD2 in IPA (108 ± 24, 7.9 ± 0.1) and CA (147 ± 58 and 8.0 ± 0.25). Protein expression of ET(A)R, ET(B)R, RhoA, and Rho-kinase were detected in IPA. IPA and CA contained preproET-1, ET(A)R, ET(B)R, RhoA, and Rho-kinase message. CONCLUSION We observed that the IPA and CA are sensitive to ET-1, signaling through the ET(A)R and Rho-kinase pathway. These data indicate that ET-1 may play a role in vaginal and clitoral blood flow and may be important in pathologies where ET-1 levels are elevated.
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Affiliation(s)
| | | | - Rita C Tostes
- Medical College of Georgia-Physiology, Augusta, GA, USA; University of Sao Paulo-Pharmacology, Sao Paulo, Brazil
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Abstract
Exposing rodents to brief episodes of hypoxia mimics the hypoxemia and the cardiovascular and metabolic effects observed in patients with obstructive sleep apnoea (OSA), a condition that affects between 5% and 20% of the population. Apart from daytime sleepiness, OSA is associated with a high incidence of systemic and pulmonary hypertension, peripheral vascular disease, stroke and sudden cardiac death. The development of animal models to study sleep apnoea has provided convincing evidence that recurrent exposure to intermittent hypoxia (IH) has significant vascular and haemodynamic impact that explain much of the cardiovascular morbidity and mortality observed in patients with sleep apnoea. However, the molecular and cellular mechanisms of how IH causes these changes is unclear and under investigation. This review focuses on the most recent findings addressing these mechanisms. It includes a discussion of the contribution of the nervous system, circulating and vascular factors, inflammatory mediators and transcription factors to IH-induced cardiovascular disease. It also highlights the importance of reactive oxygen species as a primary mediator of the systemic and pulmonary hypertension that develops in response to exposure to IH.
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Affiliation(s)
- Laura V González Bosc
- Vascular Physiology Group, Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, NM, USA.
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Abstract
Obstructive sleep apnea is characterized by repeated upper airway obstruction during sleep and affects between 5% and 20% of the population. Epidemiological studies reveal that sleep apnea and associated intermittent hypoxemia increase the risk for hypertension and vascular disease but the mechanisms underlying these effects are incompletely understood. This review reports the results of rodent models of intermittent hypoxia (IH) and relates them to the observed hemodynamic and vascular consequences of sleep apnea. These animal studies have demonstrated that IH exposure in the absence of any other comorbidity causes hypertension, endothelial dysfunction, and augmented constrictor sensitivity, all due at least in part to increased vascular oxidative stress. Animal studies have used a variety of exposure paradigms to study intermittent hypoxia and these different exposure protocols can cause hypocapnia or hypercapnia-or maintain eucapnia-with accompanying alterations in plasma pH. It appears that these different profiles of arterial blood gases can lead to divergent results but the impact of these differences is still being investigated. Overall, the studies in rodents have clearly demonstrated that the vascular and hemodynamic impact of intermittent hypoxia provides a strong rationale for treating clinical sleep apnea to prevent the resulting cardiovascular morbidity and mortality.
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Affiliation(s)
- Nancy L Kanagy
- Vascular Physiology Group, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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Snow JB, Kanagy NL, Walker BR, Resta TC. Rat strain differences in pulmonary artery smooth muscle Ca(2+) entry following chronic hypoxia. Microcirculation 2009; 16:603-14. [PMID: 19626552 DOI: 10.1080/10739680903114268] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Effects of chronic hypoxia (CH) on store- and receptor-operated Ca(2+) entry (SOCE, ROCE) in pulmonary vascular smooth muscle (VSM) are controversial, although whether genetic variation explains such discrepancies in commonly studied rat strains is unclear. Since protein kinase C (PKC) can inhibit Ca(2+) permeable nonselective cation channels, we hypothesized that CH differentially alters PKC-dependent inhibition of SOCE and ROCE in pulmonary VSM from Sprague-Dawley and Wistar rats. To test this hypothesis, we examined SOCE and endothelin-1 (ET-1)-induced ROCE in endothelium-disrupted, pressurized pulmonary arteries from control and CH Sprague-Dawley and Wistar rats. Basal VSM Ca(2+) was elevated in CH Wistar, but not Sprague-Dawley, rats. Further, CH attenuated SOCE in VSM from Sprague-Dawley rats, while augmenting this response in Wistar rats. CH reduced ROCE in arteries from both strains. PKC inhibition restored SOCE in CH Sprague-Dawley arteries to control levels, while having no effect on SOCE in Wistar arteries or on ROCE in either strain. We conclude that effects of CH on pulmonary VSM SOCE are strain dependent, whereas inhibitory effects of CH on ROCE are strain independent. Further, PKC inhibits SOCE following CH in Sprague-Dawley, but not Wistar, rats but does not contribute to ET-1-induced ROCE in either strain.
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Affiliation(s)
- Jessica B Snow
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131-0001, USA.
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Post-translational modification of proteins during intermittent hypoxia. Respir Physiol Neurobiol 2009; 164:272-6. [PMID: 18602876 DOI: 10.1016/j.resp.2008.05.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 05/22/2008] [Accepted: 05/24/2008] [Indexed: 12/14/2022]
Abstract
Post-translational modification (PTM) is one of the mechanisms by which protein function is regulated by chronic hypoxia. This article presents an overview of recent findings on PTM of proteins induced by chronic intermittent hypoxia (CIH) which is experienced by humans with sleep disordered breathing resulting in autonomic abnormalities. The analysis of PTM of proteins involves electrophoretic separation of tissue or cellular proteins followed by immunolabeling using antibodies specific to native and post-translationally modified forms. Recent results demonstrate that CIH, depending on the pattern, duration and severity of hypoxia, alters the state of phosphorylation of a subset of proteins associated with transcriptional factor activation, signaling pathways and neurotransmitter synthesis via activation of appropriate enzymatic machinery that catalyzes specific phosphorylation reactions. Investigation pertaining to PTMs associated with CIH is at its infant stage and future application of high throughput proteomics techniques are necessary to unravel other important PTMs associated with various critical metabolic and signaling pathways that are activated by intermittent hypoxia.
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Abstract
PURPOSE OF REVIEW Obstructive sleep apnea (OSA) is a prevalent disorder with clinically well known mid-term and long-term consequences. It is difficult, however, to investigate the mechanisms causing morbidity in OSA from human studies, owing to confounding factors in patients. Animal research is useful to analyze the various injurious stimuli--intermittent hypoxia/hypercapnia, mechanical stress and sleep disruption--that potentially cause OSA morbidity. This review is focused on the most recent advances in our understanding of the consequences of OSA, achieved as a result of animal models. RECENT FINDINGS Animal research has improved our knowledge of various aspects of the cardiovascular consequences of OSA: myocardial damage, left ventricular dysfunction, vasoconstriction, hypertension and atherosclerosis. The systemic and metabolic consequences of OSA--inflammation, insulin resistance, alterations in lipid metabolism and hepatic morbidity--have also been investigated with animal models. Our understanding of the mechanisms involved in the neurocognitive consequences of OSA--neuronal and brain alterations and cognitive dysfunctions--has also been improved through animal research. Moreover, animal models have recently been used to investigate the mechanisms of upper airway inflammation and dysfunction. SUMMARY The simple experimental models used to investigate OSA morbidity are useful for investigating isolated mechanisms. However, more complex and realistic models incorporating the various injurious challenges characterizing OSA are required to more precisely translate the results of animal research to patients and to design potentially preventive and therapeutic strategies.
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Allahdadi KJ, Cherng TW, Pai H, Silva AQ, Walker BR, Nelin LD, Kanagy NL. Endothelin type A receptor antagonist normalizes blood pressure in rats exposed to eucapnic intermittent hypoxia. Am J Physiol Heart Circ Physiol 2008; 295:H434-40. [PMID: 18515645 DOI: 10.1152/ajpheart.91477.2007] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have reported that eucapnic intermittent hypoxia (E-IH) causes systemic hypertension, elevates plasma endothelin 1 (ET-1) levels, and augments vascular reactivity to ET-1 and that a nonspecific ET-1 receptor antagonist acutely lowers blood pressure in E-IH-exposed rats. However, the effect of chronic ET-1 receptor inhibition has not been evaluated, and the ET receptor subtype mediating the vascular effects has not been established. We hypothesized that E-IH causes systemic hypertension through the increased ET-1 activation of vascular ET type A (ET(A)) receptors. We found that mean arterial pressure (MAP) increased after 14 days of 7 h/day E-IH exposure (109 +/- 2 to 137 +/- 4 mmHg; P < 0.005) but did not change in sham-exposed rats. The ET(A) receptor antagonist BQ-123 (10 to 1,000 nmol/kg iv) acutely decreased MAP dose dependently in conscious E-IH but not sham rats, and continuous infusion of BQ-123 (100 nmol.kg(-1).day(-1) sc for 14 days) prevented E-IH-induced increases in MAP. ET-1-induced constriction was augmented in small mesenteric arteries from rats exposed 14 days to E-IH compared with those from sham rats. Constriction was blocked by the ET(A) receptor antagonist BQ-123 (10 microM) but not by the ET type B (ET(B)) receptor antagonist BQ-788 (100 microM). ET(A) receptor mRNA content was greater in renal medulla and coronary arteries from E-IH rats. ET(B) receptor mRNA was not different in any tissues examined, whereas ET-1 mRNA was increased in the heart and in the renal medulla. Thus augmented ET-1-dependent vasoconstriction via vascular ET(A) receptors appears to elevate blood pressure in E-IH-exposed rats.
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Affiliation(s)
- Kyan J Allahdadi
- Dept. of Cell Biology and Physiology, Univ. of New Mexico Health Sciences Ctr., Albuquerque, NM 87131, USA
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