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Li Y, Anand-Srivastava MB. Role of Gi proteins in the regulation of blood pressure and vascular remodeling. Biochem Pharmacol 2023; 208:115384. [PMID: 36549460 DOI: 10.1016/j.bcp.2022.115384] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/08/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
Heterotrimeric guanine nucleotide regulatory proteins (G-proteins) through the activation of several signaling mechanisms including adenylyl cyclase/cAMP and phospholipase C (PLC)/phosphatidyl inositol (PI) turnover. regulate a variety of cellular functions, including vascular reactivity, proliferation and hypertrophy of VSMC. Activity of adenylyl cyclase is regulated by two G proteins, stimulatory (Gsα) and inhibitory (Giα). Gsα stimulates adenylyl cyclase activity and increases the levels of cAMP, whereas Giα inhibits the activity of adenylyl cyclase and results in the reduction of cAMP levels. Abnormalities in Giα protein expression and associated adenylyl cyclase\cAMP levels result in the impaired cellular functions and contribute to various pathological states including hypertension. The expression of Giα proteins is enhanced in various tissues including heart, kidney, aorta and vascular smooth muscle cells (VSMC) from genetic (spontaneously hypertensive rats (SHR)) and experimentally - induced hypertensive rats and contribute to the pathogenesis of hypertension. In addition, the enhanced expression of Giα proteins exhibited by VSMC from SHR is also implicated in the hyperproliferation and hypertrophy, the two key players contributing to vascular remodelling in hypertension. The enhanced levels of endogenous vasoactive peptides including angiotensin II (Ang II), endothelin-1 (ET-1) and growth factors contribute to the overexpression of Giα proteins in VSMC from SHR. In addition, enhanced oxidative stress, activation of c-Src, growth factor receptor transactivation and MAP kinase/PI3kinase signaling also contribute to the augmented expression of Giα proteins in VSMC from SHR. This review summarizes the role of Giα proteins, and the underlying molecular mechanisms implicated in the regulation of high blood pressure and vascular remodelling.
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Affiliation(s)
- Yuan Li
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada
| | - Madhu B Anand-Srivastava
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada.
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Lamptey RNL, Sun C, Layek B, Singh J. Neurogenic Hypertension, the Blood-Brain Barrier, and the Potential Role of Targeted Nanotherapeutics. Int J Mol Sci 2023; 24:ijms24032213. [PMID: 36768536 PMCID: PMC9916775 DOI: 10.3390/ijms24032213] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/26/2023] Open
Abstract
Hypertension is a major health concern globally. Elevated blood pressure, initiated and maintained by the brain, is defined as neurogenic hypertension (NH), which accounts for nearly half of all hypertension cases. A significant increase in angiotensin II-mediated sympathetic nervous system activity within the brain is known to be the key driving force behind NH. Blood pressure control in NH has been demonstrated through intracerebrovascular injection of agents that reduce the sympathetic influence on cardiac functions. However, traditional antihypertensive agents lack effective brain permeation, making NH management extremely challenging. Therefore, developing strategies that allow brain-targeted delivery of antihypertensives at the therapeutic level is crucial. Targeting nanotherapeutics have become popular in delivering therapeutics to hard-to-reach regions of the body, including the brain. Despite the frequent use of nanotherapeutics in other pathological conditions such as cancer, their use in hypertension has received very little attention. This review discusses the underlying pathophysiology and current management strategies for NH, as well as the potential role of targeted therapeutics in improving current treatment strategies.
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Affiliation(s)
| | | | - Buddhadev Layek
- Correspondence: (B.L.); (J.S.); Tel.: +1-701-231-7906 (B.L.); +1-701-231-7943 (J.S.); Fax: +1-701-231-8333 (B.L. & J.S.)
| | - Jagdish Singh
- Correspondence: (B.L.); (J.S.); Tel.: +1-701-231-7906 (B.L.); +1-701-231-7943 (J.S.); Fax: +1-701-231-8333 (B.L. & J.S.)
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Sirtuin1 inhibitor attenuates hypertension in spontaneously hypertensive rats: role of Giα proteins and nitroxidative stress. J Hypertens 2022; 40:1314-1326. [PMID: 35762472 DOI: 10.1097/hjh.0000000000003143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND We recently showed that vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR) exhibit overexpression of Sirtuin1 (Sirt1) that contributes to the enhanced expression of Giα proteins implicated in the development of hypertension in SHR. METHOD The present study investigated if the inhibition of Sirt1 could also ameliorate hypertension in SHR and explore the underlying molecular mechanisms. For this study, a selective inhibitor of Sirt1, EX-527 (5 mg/kg of body weight), was injected intraperitoneally into 8-week-old SHR and age-matched Wistar Kyoto (WKY) rats twice per week for 3 weeks. The blood pressure (BP) and heart rate was measured twice a week by the CODA noninvasive tail cuff method. RESULTS The high BP and augmented heart rate in SHR was significantly attenuated by EX-527 treatment, which was associated with the suppression of the overexpression of Sirt1 and Giα proteins in heart, VSMC and aorta. In addition, the enhanced levels of superoxide anion, NADPH oxidase activity, overexpression of NADPH oxidase subunits and FOXO1 were attenuated and the decreased levels of endothelial nitric oxide synthase (eNOS), nitric oxide and increased levels of peroxynitrite (ONOO-) and tyrosine nitration in VSMC from SHR were restored to control levels by EX-527 treatment. Furthermore, knockdown of FOXO1 by siRNA also attenuated the overexpression of Giα-2 and NADPH oxidase subunit proteins and restored the decreased expression of eNOS in VSMC from SHR. CONCLUSION These results suggest that the inhibition of overexpressed Sirt1 and its target FOXO1 through decreasing the enhanced levels of Giα proteins and nitro-oxidative stress attenuates the high BP in SHR.
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Li Y, Hossain E, Arifen N, Srivastava AK, Anand-Srivastava MB. Sirtuin1 contributes to the overexpression of Giα proteins and hyperproliferation of vascular smooth muscle cells from spontaneously hypertensive rats. J Hypertens 2022; 40:117-127. [PMID: 34420010 DOI: 10.1097/hjh.0000000000002985] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND We earlier demonstrated that vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) exhibit the overexpression of Giα proteins and hyperproliferation that is attributed to the enhanced levels of endogenous angiotensin II (Ang II). In addition, the implication of Sirtuin1 (Sirt1) a histone deacetylase class III family in Ang II-induced hypertension has also been shown. We recently demonstrated that Ang II increased the expression of Sirt1 in aortic VSMC that contributed to the overexpression of Giα proteins. However, whether Sirt1 is overexpressed in VSMC from SHR and is linked to the enhanced expression of Giα proteins and hyperproliferation remains unexplored. METHOD AND RESULTS In the present study, we show that Sirt1 is upregulated in VSMC from SHR and this upregulation was attenuated by AT1 receptor antagonist losartan. In addition, the inhibition or knockdown of Sirt1 by specific inhibitors EX 527 and NAM and/or siRNA attenuated the enhanced expression of Giα proteins, cell cycle proteins and hyperproliferation of VSMC from SHR. Furthermore, the enhanced levels of reactive oxygen species (ROS), hydrogen peroxide and NADPH oxidase subunits NOX2 and p47phox, increased phosphorylation of EGFR, ERK1/2 and AKT displayed by VSMC from SHR were also attenuated by knocking down of Sirt1 by siRNA. CONCLUSION In summary, our results demonstrate that Sirt1 is overexpressed in VSMC from SHR which through augmenting oxidative stress contributes to the enhanced expression of Giα proteins, cell cycle proteins and resultant hyperproliferation of VSMC.
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Affiliation(s)
- Yuan Li
- Department of Pharmacology and Physiology, Faculty of Medicine
| | - Ekhtear Hossain
- Department of Pharmacology and Physiology, Faculty of Medicine
| | - Nahida Arifen
- Department of Pharmacology and Physiology, Faculty of Medicine
| | - Ashok K Srivastava
- CRCHUM, Department of Medicine, University of Montreal, Montreal, Canada
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Hossain E, Li Y, Anand-Srivastava MB. Angiotensin II-induced overexpression of sirtuin 1 contributes to enhanced expression of Giα proteins and hyperproliferation of vascular smooth muscle cells. Am J Physiol Heart Circ Physiol 2021; 321:H496-H508. [PMID: 34270373 DOI: 10.1152/ajpheart.00898.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Angiotensin II (ANG II) plays an important role in the regulation of various physiological functions including proliferation, hypertrophy of vascular smooth muscle cells (VSMCs) through the overexpression of Giα proteins. Sirtuin 1 (Sirt1), a class III histone deacetylase and epigenetic regulator is implicated in a wide range of cellular functions, including migration and growth of VSMCs and in ANG II-induced hypertension. The present study was undertaken to examine the role of Sirt1 in ANG II-induced overexpression of Giα proteins and hyperproliferation of aortic VSMCs. We show that ANG II treatment of VSMCs increased the expression of Sirt1, which was attenuated by AT1 and AT2 receptor antagonists, losartan, and PD123319, respectively. In addition, the knockdown of Sirt1 by siRNA attenuated ANG II-induced overexpression of Giα-2 and Giα-3 proteins, hyperproliferation of VSMCs and the overexpression of cell cycle proteins, cyclin D1, Cdk4, and phosphorylated retinoblastoma proteins. Furthermore, ANG II-induced increased levels of superoxide anion (O2-) and NADPH oxidase activity and increased phosphorylation of ERK1/2 and Akt that are implicated in enhanced expression of Giα proteins and hyperproliferation of VSMCs were also attenuated to control levels by silencing of Sirt1. In addition, depletion of Sirt1 by siRNA also attenuated ANG II-induced enhanced phosphorylation of platelet-derived growth factor receptor (PDGFR), epidermal growth factor receptor (EGFR), and insulin-like growth factor receptor (IGFR) in VSMCs. In summary, our results demonstrate that ANG II increased the expression of Sirt1, which through oxidative stress, growth factor receptor-mediated mitogen-activated protein (MAP) kinase/Akt signaling pathway enhances the expression of Giα proteins and cell cycle proteins and results in the hyperproliferation of VSMCs.NEW & NOTEWORTHY ANG II regulates various physiological functions including proliferation of VSMCs through the overexpression of Giα proteins. Sirt1, a class III histone deacetylase, is implicated in several cellular functions, including VSMC growth and ANG II-induced hypertension. We showed for the first time that ANG II increased the expression of Sirt1, which through oxidative stress, growth factor receptor-mediated MAP kinase/Akt signaling pathway enhances the levels of Giα and cell cycle proteins resulting in the hyperproliferation of VSMCs.
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Affiliation(s)
- Ekhtear Hossain
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montréal, Montréal, Quebec, Canada
| | - Yuan Li
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montréal, Montréal, Quebec, Canada
| | - Madhu B Anand-Srivastava
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montréal, Montréal, Quebec, Canada
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Sarkar O, Li Y, Anand-Srivastava MB. Resveratrol prevents the development of high blood pressure in spontaneously hypertensive rats through the inhibition of enhanced expression of Giα proteins. Can J Physiol Pharmacol 2019; 97:872-879. [DOI: 10.1139/cjpp-2019-0040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Resveratrol (RV), a polyphenolic component of red wine, has been shown to attenuate high blood pressure (BP) in spontaneously hypertensive rats (SHRs). We previously found that the enhanced expression of Giα proteins plays a role in the pathogenesis of hypertension in SHRs. In the present study, we investigated whether this RV-induced decrease in BP in SHRs can be attributed to the ability of RV to inhibit the enhanced expression of Giα proteins and the upstream signaling molecules implicated in the overexpression of Giα proteins. Administration of RV (50 mg/kg per day) to prehypertensive 2-week-old SHRs for 6 weeks prevented the development of high BP and inhibited the enhanced expression of Giα proteins, the enhanced levels of superoxide anion (O2−) and NADPH oxidase activity, the enhanced activation (phosphorylation) of c-Src and growth factor receptors, as well as the enhanced levels of extracellular signal-regulated kinase 1/2 (ERK1/2) and protein kinase B (Akt) exhibited by vascular smooth muscle cells isolated from SHRs. In conclusion, these results indicate that RV attenuates the development of high BP in SHRs through the inhibition of enhanced levels of Giα proteins, oxidative stress, and the upstream signaling molecules that contribute to the overexpression of Giα proteins. These findings suggest that RV could potentially be used as a therapeutic agent in the treatment of cardiovascular complications including hypertension.
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Affiliation(s)
- Oli Sarkar
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC H3C 3J7, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC H3C 3J7, Canada
| | - Yuan Li
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC H3C 3J7, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC H3C 3J7, Canada
| | - Madhu B. Anand-Srivastava
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC H3C 3J7, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, QC H3C 3J7, Canada
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Giguère N, Delignat-Lavaud B, Herborg F, Voisin A, Li Y, Jacquemet V, Anand-Srivastava M, Gether U, Giros B, Trudeau LÉ. Increased vulnerability of nigral dopamine neurons after expansion of their axonal arborization size through D2 dopamine receptor conditional knockout. PLoS Genet 2019; 15:e1008352. [PMID: 31449520 PMCID: PMC6730950 DOI: 10.1371/journal.pgen.1008352] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 09/06/2019] [Accepted: 08/07/2019] [Indexed: 01/20/2023] Open
Abstract
Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). Rare genetic mutations in genes such as Parkin, Pink1, DJ-1, α-synuclein, LRRK2 and GBA are found to be responsible for the disease in about 15% of the cases. A key unanswered question in PD pathophysiology is why would these mutations, impacting basic cellular processes such as mitochondrial function and neurotransmission, lead to selective degeneration of SNc DA neurons? We previously showed in vitro that SNc DA neurons have an extremely high rate of mitochondrial oxidative phosphorylation and ATP production, characteristics that appear to be the result of their highly complex axonal arborization. To test the hypothesis in vivo that axon arborization size is a key determinant of vulnerability, we selectively labeled SNc or VTA DA neurons using floxed YFP viral injections in DAT-cre mice and showed that SNc DA neurons have a much more arborized axon than those of the VTA. To further enhance this difference, which may represent a limiting factor in the basal vulnerability of these neurons, we selectively deleted in mice the DA D2 receptor (D2-cKO), a key negative regulator of the axonal arbour of DA neurons. In these mice, SNc DA neurons have a 2-fold larger axonal arborization, release less DA and are more vulnerable to a 6-OHDA lesion, but not to α-synuclein overexpression when compared to control SNc DA neurons. This work adds to the accumulating evidence that the axonal arborization size of SNc DA neurons plays a key role in their vulnerability in the context of PD. Parkinson’s disease motor symptoms have been linked to age-dependent degeneration of a class of neurons in the brain that release the chemical messenger dopamine. The reason for the selective loss of these neurons represents a key unsolved mystery. One hypothesis is that the neurons most at risk in this disease are those with the most extensive and complex connectivity in the brain, which would make these cells most dependent on high rates of mitochondrial energy production and expose them to higher rates of oxidative stress. Here we selectively deleted in dopamine neurons a key gene providing negative feedback control of the axonal arbor size of these neurons, in the objective of producing mice in which dopamine neurons have more extensive connectivity. We found that deletion of the dopamine D2 receptor gene in dopamine neurons leads to dopamine neurons with a longer and more complex axonal domain. We also found that in these mice, dopamine neurons in a region of the brain called the substantia nigra show increased vulnerability to a neurotoxin often used to model Parkinson’s disease in rodents. Our findings provide support for the hypothesis that the scale of a neuron’s connectivity directly influences its vulnerability to cellular stressors that trigger Parkinson’s disease.
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Affiliation(s)
- Nicolas Giguère
- Departments of pharmacology and physiology, Department of neurosciences, Central Nervous System Research Group (GRSNC), Faculty of Medicine, Université de Montréal, Québec, Canada
| | - Benoît Delignat-Lavaud
- Departments of pharmacology and physiology, Department of neurosciences, Central Nervous System Research Group (GRSNC), Faculty of Medicine, Université de Montréal, Québec, Canada
| | - Freja Herborg
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Aurore Voisin
- Departments of pharmacology and physiology, Department of neurosciences, Central Nervous System Research Group (GRSNC), Faculty of Medicine, Université de Montréal, Québec, Canada
| | - Yuan Li
- Department of pharmacology and physiology, Faculty of Medicine, Université de Montréal, Québec, Canada
| | - Vincent Jacquemet
- Department of pharmacology and physiology, Research Center of the Hôpital de Sacré-Coeur de Montréal, Montréal, Québec, Canada
| | - Madhu Anand-Srivastava
- Department of pharmacology and physiology, Faculty of Medicine, Université de Montréal, Québec, Canada
| | - Ulrik Gether
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bruno Giros
- Department of Psychiatry, McGill University Faculty of Medicine, Douglas Mental Health University Institute, Montreal, Québec, Canada
| | - Louis-Éric Trudeau
- Departments of pharmacology and physiology, Department of neurosciences, Central Nervous System Research Group (GRSNC), Faculty of Medicine, Université de Montréal, Québec, Canada
- * E-mail:
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Hossain E, Sarkar O, Li Y, Anand-Srivastava MB. Inhibition of overexpression of Giα proteins and nitroxidative stress contribute to sodium nitroprusside-induced attenuation of high blood pressure in SHR. Physiol Rep 2019; 6:e13658. [PMID: 29595917 PMCID: PMC5875540 DOI: 10.14814/phy2.13658] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/13/2017] [Accepted: 01/15/2018] [Indexed: 01/08/2023] Open
Abstract
We earlier showed that vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) exhibit enhanced expression of Giα proteins which was attributed to the decreased levels of nitric oxide (NO), because elevation of the intracellular levels of NO by NO donors; sodium nitroprusside (SNP) and S-Nitroso-N-acetyl-DL-penicillamine (SNAP), attenuated the enhanced expression of Giα proteins. Since the enhanced expression of Giα proteins is implicated in the pathogenesis of hypertension, the present study was undertaken to investigate if treatment of SHR with SNP could also attenuate the development of high blood pressure (BP) and explore the underlying molecular mechanisms. Intraperitoneal injection of SNP at a concentration of 0.5 mg/kg body weight twice a week for 2 weeks into SHR attenuated the high blood pressure by about 80 mmHg without affecting the BP in WKY rats. SNP treatment also attenuated the enhanced levels of superoxide anion (O2- ), hydrogen peroxide (H2 O2 ), peroxynitrite (ONOO- ), and NADPH oxidase activity in VSMC from SHR to control levels. In addition, the overexpression of different subunits of NADPH oxidase; Nox-1, Nox-2, Nox-4, P22phox , and P47phox , and Giα proteins in VSMC from SHR were also attenuated by SNP treatment. On the other hand, SNP treatment augmented the decreased levels of intracellular NO, eNOS, and cGMP in VSMC from SHR. These results suggest that SNP treatment attenuates the development of high BP in SHR through the elevation of intracellular levels of cGMP and inhibition of the enhanced levels of Giα proteins and nitroxidative stress.
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Affiliation(s)
- Ekhtear Hossain
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada
| | - Oli Sarkar
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada
| | - Yuan Li
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada
| | - Madhu B Anand-Srivastava
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Canada
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Almajdoob S, Hossain E, Anand-Srivastava MB. Resveratrol attenuates hyperproliferation of vascular smooth muscle cells from spontaneously hypertensive rats: Role of ROS and ROS-mediated cell signaling. Vascul Pharmacol 2018; 101:48-56. [DOI: 10.1016/j.vph.2017.12.064] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/13/2017] [Accepted: 12/18/2017] [Indexed: 02/07/2023]
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