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Lee HM, Yoon SH, Kim MG, Hahn SJ, Choi BH. Effects of rosiglitazone, an antidiabetic drug, on Kv3.1 channels. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2023; 27:95-103. [PMID: 36575937 PMCID: PMC9806636 DOI: 10.4196/kjpp.2023.27.1.95] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/20/2022] [Accepted: 10/22/2022] [Indexed: 12/29/2022]
Abstract
Rosiglitazone is a thiazolidinedione-class antidiabetic drug that reduces blood glucose and glycated hemoglobin levels. We here investigated the interaction of rosiglitazone with Kv3.1 expressed in Chinese hamster ovary cells using the whole-cell patch-clamp technique. Rosiglitazone rapidly and reversibly inhibited Kv3.1 currents in a concentration-dependent manner (IC50 = 29.8 μM) and accelerated the decay of Kv3.1 currents without modifying the activation kinetics. The rosiglitazone-mediated inhibition of Kv3.1 channels increased steeply in a sigmoidal pattern over the voltage range of -20 to +30 mV, whereas it was voltage-independent in the voltage range above +30 mV, where the channels were fully activated. The deactivation of Kv3.1 current, measured along with tail currents, was also slowed by the drug. In addition, the steady-state inactivation curve of Kv3.1 by rosiglitazone shifts to a negative potential without significant change in the slope value. All the results with the use dependence of the rosiglitazone-mediated blockade suggest that rosiglitazone acts on Kv3.1 channels as an open channel blocker.
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Affiliation(s)
- Hyang Mi Lee
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea
| | - Seong Han Yoon
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea
| | - Min-Gul Kim
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea
| | - Sang June Hahn
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Bok Hee Choi
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea,Correspondence Bok Hee Choi, E-mail:
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Lee HM, Hahn SJ, Choi BH. The antidiabetic drug rosiglitazone blocks Kv1.5 potassium channels in an open state. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY 2022; 26:135-144. [PMID: 35203063 PMCID: PMC8890944 DOI: 10.4196/kjpp.2022.26.2.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/15/2022] [Accepted: 01/17/2022] [Indexed: 11/15/2022]
Abstract
An antidiabetic drug, rosiglitazone is a member of the drug class of thiazolidinedione. Although restrictions on use due to the possibility of heart toxicity have been removed, it is still a drug that is concerned about side effects on the heart. We here examined, using Chinese hamster ovary cells, the action of rosiglitazone on Kv1.5 channels, which is a major determinant of the duration of cardiac action potential. Rosiglitazone rapidly and reversibly inhibited Kv1.5 currents in a concentration-dependent manner (IC50 = 18.9 µM) and accelerated the decay of Kv1.5 currents without modifying the activation kinetics. In addition, the deactivation of Kv1.5 current, assayed with tail current, was slowed by the drug. All of the results as well as the use-dependence of the rosiglitazone-mediated blockade indicate that rosiglitazone acts on Kv1.5 channels as an open channel blocker. This study suggests that the cardiac side effects of rosiglitazone might be mediated in part by suppression of Kv1.5 channels, and therefore, raises a concern of using the drug for diabetic therapeutics.
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Affiliation(s)
- Hyang Mi Lee
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea
| | - Sang June Hahn
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Bok Hee Choi
- Department of Pharmacology, Institute for Medical Sciences, Jeonbuk National University Medical School, Jeonju 54097, Korea
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15-Deoxy-Δ- 12,14-prostaglandin J2 effects in vascular smooth muscle cells: Implications in vascular smooth muscle cell proliferation and contractility. Prostaglandins Other Lipid Mediat 2021; 156:106583. [PMID: 34332056 DOI: 10.1016/j.prostaglandins.2021.106583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 06/04/2021] [Accepted: 07/23/2021] [Indexed: 10/20/2022]
Abstract
15-Deoxy-Δ-12,14-prostaglandin J2 (15d-PGJ2) is an endogenous agonist of the ligand dependent transcriptional factor, peroxisome proliferator-activated receptor -gamma (PPAR-γ). Although PPAR-γ mediates some actions of 15d-PGJ2, many actions of 15d-PGJ2 are independent of PPAR-γ. The PPAR-γ signaling pathway has beneficial effects on tumor progression, inflammation, oxidative stress, and angiogenesis in numerous studies. In this review, various studies were analyzed to understand the effects of 15d-PGJ2 in vascular smooth muscle cells (VSMC)s. 15d-PGJ2 inhibits proliferation of VSMCs during vascular remodeling and it alters the expression of contractile proteins and inflammatory components within these cells as well. However, the effects of 15d-PGJ2 as well as its ability to induce PPAR-γ activation remains controversial as contradictory effects of this prostaglandin in VSMCs exist. Understanding the mechanisms by which 15d-PGJ2 elicit beneficial actions whether by PPAR-γ activation or independently, will aid in developing new therapeutic strategies for diseases such as hypertension with an inflammatory component. Although great advances are being made, more research is needed to reach definitive conclusions.
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Ye BH, Kim EJ, Baek SE, Choi YW, Park SY, Kim CD. α-Isocubebene modulates vascular tone by inhibiting myosin light chain phosphorylation in murine thoracic aorta. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2018; 22:437-445. [PMID: 29962858 PMCID: PMC6019879 DOI: 10.4196/kjpp.2018.22.4.437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/23/2018] [Accepted: 04/24/2018] [Indexed: 02/07/2023]
Abstract
α-Iso-cubebene (ICB) is a dibenzocyclooctadiene lignin contained in Schisandra chinensis (SC), a well-known medicinal herb that ameliorates cardiovascular symptoms, but the mechanism responsible for this activity has not been determined. To determine the role played by ICB on the regulation of vascular tone, we investigated the inhibitory effects of ICB on vascular contractile responses by adrenergic α-receptor agonists. In addition, we investigated the role on myosin light chain (MLC) phosphorylation and cytosolic calcium concentration in vascular smooth muscle cells (VSMC). In aortic rings isolated from C57BL/6J mice, ICB significantly attenuated the contraction induced by phenylephrine (PE) and norepinephrine (NE), whereas ICB had no effects on KCl (60 mM)-induced contraction. In vasculatures precontracted with PE, ICB caused marked relaxation of aortic rings with or without endothelium, suggesting a direct effect on VSMC. In cultured rat VSMC, PE or NE increased MLC phosphorylation and increased cytosolic calcium levels. Both of these effects were significantly suppressed by ICB. In conclusion, our results showed that ICB regulated vascular tone by inhibiting MLC phosphorylation and calcium flux into VSMC, and suggest that ICB has anti-hypertensive properties and therapeutic potential for cardiovascular disorders related to vascular hypertension.
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Affiliation(s)
- Byeong Hyeok Ye
- Department of Pharmacology, School of Medicine, Pusan National University, Yangsan 50612, Korea
| | - Eun Jung Kim
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Yangsan 50612, Korea
| | - Seung Eun Baek
- Department of Pharmacology, School of Medicine, Pusan National University, Yangsan 50612, Korea.,Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Yangsan 50612, Korea
| | - Young Whan Choi
- College of Natural Resources & Life Sciences, Pusan National University, Miryang 50463, Korea
| | - So Youn Park
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Yangsan 50612, Korea
| | - Chi Dae Kim
- Department of Pharmacology, School of Medicine, Pusan National University, Yangsan 50612, Korea.,Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Yangsan 50612, Korea
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Zheng C, Zhong M, Qi Z, Shen F, Zhao Q, Wu L, Huang Y, Tsang SY, Yao X. Histone Deacetylase Inhibitors Relax Mouse Aorta Partly through Their Inhibitory Action on L-Type Ca 2+ Channels. J Pharmacol Exp Ther 2017; 363:211-220. [PMID: 28860353 DOI: 10.1124/jpet.117.242685] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 08/21/2017] [Indexed: 12/21/2022] Open
Abstract
Histone deacetylase (HDAC) inhibitors modulate acetylation/deacetylation of histone and nonhistone proteins. They have been widely used for cancer treatment. However, there have been only a few studies investigating the effect of HDAC inhibitors on vascular tone regulation, most of which employed chronic treatment with HDAC inhibitors. In the present study, we found that two hydroxamate-based pan-HDAC inhibitors, suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA), could partially but acutely relax high extracellular K+-contracted mouse aortas. SAHA and TSA also attenuated the high extracellular K+-induced cytosolic Ca2+ rise and inhibited L-type Ca2+ channel current in whole-cell patch-clamp. These data demonstrate that SAHA could inhibit L-type Ca2+ channels to cause vascular relaxation. In addition, SAHA and TSA dose dependently relaxed the arteries precontracted with phenylephrine. The relaxant effect of SAHA and TSA was greater in phenylephrine-precontracted arteries than in high K+-contracted arteries. Although part of the relaxant effect of SAHA and TSA on phenylephrine-precontracted arteries was related to L-type Ca2+ channels, both agents could also induce relaxation via a mechanism independent of L-type Ca2+ channels. Taken together, HDAC inhibitors SAHA and TSA can acutely relax blood vessels via their inhibitory action on L-type Ca2+ channels and via another L-type Ca2+ channel-independent mechanism.
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Affiliation(s)
- Changbo Zheng
- Department of Physiology, Anhui Medical University, Hefei, China (M.Z., F.S.); School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan, China (C.Z.); and School of Biomedical Sciences and Li Ka Shing Institute of Health Science (C.Z., Q.Z., L.W., Y.H., X.Y.), School of Life Sciences (S.-Y.T, Z.Q.), Shenzhen Research Institute (C.Z., Q.Z., L.W., X.Y.), The Chinese University of Hong Kong, Shenzhen, China
| | - Mingkui Zhong
- Department of Physiology, Anhui Medical University, Hefei, China (M.Z., F.S.); School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan, China (C.Z.); and School of Biomedical Sciences and Li Ka Shing Institute of Health Science (C.Z., Q.Z., L.W., Y.H., X.Y.), School of Life Sciences (S.-Y.T, Z.Q.), Shenzhen Research Institute (C.Z., Q.Z., L.W., X.Y.), The Chinese University of Hong Kong, Shenzhen, China.
| | - Zenghua Qi
- Department of Physiology, Anhui Medical University, Hefei, China (M.Z., F.S.); School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan, China (C.Z.); and School of Biomedical Sciences and Li Ka Shing Institute of Health Science (C.Z., Q.Z., L.W., Y.H., X.Y.), School of Life Sciences (S.-Y.T, Z.Q.), Shenzhen Research Institute (C.Z., Q.Z., L.W., X.Y.), The Chinese University of Hong Kong, Shenzhen, China
| | - Fan Shen
- Department of Physiology, Anhui Medical University, Hefei, China (M.Z., F.S.); School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan, China (C.Z.); and School of Biomedical Sciences and Li Ka Shing Institute of Health Science (C.Z., Q.Z., L.W., Y.H., X.Y.), School of Life Sciences (S.-Y.T, Z.Q.), Shenzhen Research Institute (C.Z., Q.Z., L.W., X.Y.), The Chinese University of Hong Kong, Shenzhen, China
| | - Qiannan Zhao
- Department of Physiology, Anhui Medical University, Hefei, China (M.Z., F.S.); School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan, China (C.Z.); and School of Biomedical Sciences and Li Ka Shing Institute of Health Science (C.Z., Q.Z., L.W., Y.H., X.Y.), School of Life Sciences (S.-Y.T, Z.Q.), Shenzhen Research Institute (C.Z., Q.Z., L.W., X.Y.), The Chinese University of Hong Kong, Shenzhen, China
| | - Lulu Wu
- Department of Physiology, Anhui Medical University, Hefei, China (M.Z., F.S.); School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan, China (C.Z.); and School of Biomedical Sciences and Li Ka Shing Institute of Health Science (C.Z., Q.Z., L.W., Y.H., X.Y.), School of Life Sciences (S.-Y.T, Z.Q.), Shenzhen Research Institute (C.Z., Q.Z., L.W., X.Y.), The Chinese University of Hong Kong, Shenzhen, China
| | - Yu Huang
- Department of Physiology, Anhui Medical University, Hefei, China (M.Z., F.S.); School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan, China (C.Z.); and School of Biomedical Sciences and Li Ka Shing Institute of Health Science (C.Z., Q.Z., L.W., Y.H., X.Y.), School of Life Sciences (S.-Y.T, Z.Q.), Shenzhen Research Institute (C.Z., Q.Z., L.W., X.Y.), The Chinese University of Hong Kong, Shenzhen, China
| | - Suk-Ying Tsang
- Department of Physiology, Anhui Medical University, Hefei, China (M.Z., F.S.); School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan, China (C.Z.); and School of Biomedical Sciences and Li Ka Shing Institute of Health Science (C.Z., Q.Z., L.W., Y.H., X.Y.), School of Life Sciences (S.-Y.T, Z.Q.), Shenzhen Research Institute (C.Z., Q.Z., L.W., X.Y.), The Chinese University of Hong Kong, Shenzhen, China
| | - Xiaoqiang Yao
- Department of Physiology, Anhui Medical University, Hefei, China (M.Z., F.S.); School of Pharmaceutical Science and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan, China (C.Z.); and School of Biomedical Sciences and Li Ka Shing Institute of Health Science (C.Z., Q.Z., L.W., Y.H., X.Y.), School of Life Sciences (S.-Y.T, Z.Q.), Shenzhen Research Institute (C.Z., Q.Z., L.W., X.Y.), The Chinese University of Hong Kong, Shenzhen, China.
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Peuler JD, Phelps LE. Sildenafil does not enhance but rather attenuates vasorelaxant effects of antidiabetic agents. J Smooth Muscle Res 2015; 51:22-36. [PMID: 26004378 PMCID: PMC5137313 DOI: 10.1540/jsmr.51.22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Type 2 diabetic men commonly experience erectile dysfunction for which
phosphodiesterase-5 (PDE5) inhibitors like sildenafil (Viagra) are often recommended. By
preventing degradation of cyclic guanosine monophosphate (cGMP) in vascular smooth muscle,
these inhibitors also enhance arterial vasorelaxant effects of nitric oxide donors (which
stimulate cGMP synthesis). In the present work, we confirmed this enhancing effect after
co-administration of sildenafil with nitroprusside to freshly-isolated rat tail arterial
tissues. However, in the same tissues we also observed that sildenafil does not enhance
but rather attenuates vasorelaxant effects of three commonly-used antidiabetic drugs, i.e.
the biguanide metformin and the thiazolidinediones pioglitazone and rosiglitazone. Indeed,
sildenafil completely blocked vasorelaxant effects of low concentrations of these drugs.
In addition, we found that this same novel anti-vasorelaxant interaction of sildenafil
with these agents was abolished by either 1) omitting extracellular glucose or 2)
inhibiting specific smooth muscle glycolytic pathways; pathways known to preferentially
utilize extracellular glucose to fuel certain adenosine triphosphate (ATP)-dependent ion
transporters: e.g. ATP-sensitive K channels, sarcoplasmic reticulum Ca-ATPase, plasma
membrane Ca-ATPase and Na/K-ATPase. Accordingly, we suspect that altered activity of one
or more of these ion transporters mediates the observed attenuating (anti-vasorelaxant)
interaction of sildenafil with the antidiabetic drugs. The present results are relevant
because hypertension is so common and difficult to control in Type 2 diabetes. The present
data suggest that sildenafil might interfere with the known antihypertensive potential of
metformin and the thiazolidinediones. However, they do not suggest that it will interact
with them to cause life-threatening episodes of severe hypotension, as can occur when it
is co-administered with nitrates.
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Affiliation(s)
- Jacob D Peuler
- Department of Pharmacology, Midwestern University, Downers Grove, IL, USA
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Pradhan I, Ledent C, Mustafa SJ, Morisseau C, Nayeem MA. High salt diet modulates vascular response in A2AAR (+/+) and A 2AAR (-/-) mice: role of sEH, PPARγ, and K ATP channels. Mol Cell Biochem 2015; 404:87-96. [PMID: 25739357 DOI: 10.1007/s11010-015-2368-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/21/2015] [Indexed: 10/23/2022]
Abstract
This study aims to investigate the signaling mechanism involved in HS-induced modulation of adenosine-mediated vascular tone in the presence or absence of adenosine A2A receptor (A2AAR). We hypothesized that HS-induced enhanced vascular relaxation through A2AAR and epoxyeicosatrienoic acid (EETs) is dependent on peroxisome proliferator-activated receptor gamma (PPARγ) and ATP-sensitive potassium channels (KATP channels) in A2AAR(+/+) mice, while HS-induced vascular contraction to adenosine is dependent on soluble epoxide hydrolase (sEH) that degrades EETs in A2AAR(-/-) mice. Organ bath and Western blot techniques were conducted in HS (4 % NaCl) and normal salt (NS, 0.45 % NaCl)-fed A2AAR(+/+) and A2AAR(-/-) mouse aorta. We found that enhanced vasodilation to A2AAR agonist, CGS 21680, in HS-fed A2AAR(+/+) mice was blocked by PPARγ antagonist (T0070907) and KATP channel blocker (Glibenclamide). Also, sEH inhibitor (AUDA)-dependent vascular relaxation was mitigated by PPARγ antagonist. PPARγ agonist (Rosiglitazone)-induced relaxation in HS-A2AAR(+/+) mice was attenuated by KATP channel blocker. Conversely, HS-induced contraction in A2AAR(-/-) mice was attenuated by sEH inhibitor. Overall, findings from this study that implicates the contribution of EETs, PPARγ and KATP channels downstream of A2AAR to mediate enhanced vascular relaxation in response to HS diet while, role of sEH in mediating vascular contraction in HS-fed A2AAR(-/-) mice.
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Affiliation(s)
- Isha Pradhan
- Department of Physiology & Pharmacology/Department of Basic Pharmaceutical Sciences, Center for Cardiovascular and Respiratory Sciences, School of Medicine/School of Pharmacy, West Virginia University, Biomedical Research Building, 2nd Floor, Room # 220, 3051 Health Science Center - North 1 Medical Center Drive, P. O. Box 9229, Morgantown, WV, 26506-9229, USA
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PPARgamma-Dependent Control of Renin Expression: Molecular Mechanisms and Pathophysiological Relevance. PPAR Res 2013; 2013:451016. [PMID: 24288524 PMCID: PMC3832966 DOI: 10.1155/2013/451016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/19/2013] [Indexed: 11/24/2022] Open
Abstract
During the last years accumulating evidence demonstrated that the nuclear receptor peroxisome proliferator-activated receptor-gamma (PPARgamma) regulates the expression of renin gene and thus the overall renin production. This review summarizes the current knowledge of the transcriptional control of the renin gene by PPARgamma received from variety of models ranging from cell culture to transgenic animals. The molecular mechanisms of the PPARgamma action on renin are particularly interesting because they are featured by two newly described characteristics: one of them is the recently identified PPARgamma target sequence Pal3 which is specific for the human renin gene and mediates exceptionally high sensitivity to transactivation; the other is the potentiating effect of PPARgamma on the cAMP signaling in the renin-producing cells. Furthermore, I discuss the need for generating of additional transgenic animal models which are more appropriate with regard to the role of the PPARgamma-dependent regulation of the renin gene expression in human diseases such as arterial hypertension and metabolic syndrome.
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Reversible inhibition of vasoconstriction by thiazolidinediones related to PI3K/Akt inhibition in vascular smooth muscle cells. Biochem Pharmacol 2013. [DOI: 10.1016/j.bcp.2012.11.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Yu L, Jin X, Cui N, Wu Y, Shi Z, Zhu D, Jiang C. Rosiglitazone selectively inhibits K(ATP) channels by acting on the K(IR) 6 subunit. Br J Pharmacol 2013; 167:26-36. [PMID: 22394376 DOI: 10.1111/j.1476-5381.2012.01934.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE Rosiglitazone is an anti-diabetic drug acting as an insulin sensitizer. We recently found that rosiglitazone also inhibits the vascular isoform of ATP-sensitive K(+) channels and compromises vasodilatory effects of β-adrenoceptor activation and pinacidil. As its potency for the channel inhibition is in the micromolar range, rosiglitazone may be used as an effective K(ATP) channel inhibitor for research and therapeutic purposes. Therefore, we performed experiments to determine whether other isoforms of K(ATP) channels are also sensitive to rosiglitazone and what their sensitivities are. EXPERIMENTAL APPROACH K(IR) 6.1/SUR2B, K(IR) 6.2/SUR1, K(IR) 6.2/SUR2A, K(IR) 6.2/SUR2B and K(IR) 6.2ΔC36 channels were expressed in HEK293 cells and were studied using patch-clamp techniques. KEY RESULTS Rosiglitazone inhibited all isoforms of K(ATP) channels in excised patches and in the whole-cell configuration. Its IC(50) was 10 µmol·L(-1) for the K(IR) 6.1/SUR2B channel and ∼45 µmol·L(-1) for K(IR) 6.2/SURx channels. Rosiglitazone also inhibited K(IR) 6.2ΔC36 channels in the absence of the sulphonylurea receptor (SUR) subunit, with potency (IC(50) = 45 µmol·L(-1) ) almost identical to that for K(IR) 6.2/SURx channels. Single-channel kinetic analysis showed that the channel inhibition was mediated by augmentation of the long-lasting closures without affecting the channel open state and unitary conductance. In contrast, rosiglitazone had no effect on K(IR) 1.1, K(IR) 2.1 and K(IR) 4.1 channels, suggesting that the channel inhibitory effect is selective for K(IR) 6.x channels. CONCLUSIONS AND IMPLICATIONS These results suggest a novel K(ATP) channel inhibitor that acts on the pore-forming K(IR) 6.x subunit, affecting the channel gating.
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Affiliation(s)
- Lei Yu
- Department of Biology, Georgia State University, Atlanta, Georgia 30302-4010, USA.
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Hoffmann BR, El-Mansy MF, Sem DS, Greene AS. Chemical proteomics-based analysis of off-target binding profiles for rosiglitazone and pioglitazone: clues for assessing potential for cardiotoxicity. J Med Chem 2012; 55:8260-71. [PMID: 22970990 PMCID: PMC4113394 DOI: 10.1021/jm301204r] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Drugs exert desired and undesired effects based on their binding interactions with protein target(s) and off-target(s), providing evidence for drug efficacy and toxicity. Pioglitazone and rosiglitazone possess a common functional core, glitazone, which is considered a privileged scaffold upon which to build a drug selective for a given target--in this case, PPARγ. Herein, we report a retrospective analysis of two variants of the glitazone scaffold, pioglitazone and rosiglitazone, in an effort to identify off-target binding events in the rat heart to explain recently reported cardiovascular risk associated with these drugs. Our results suggest that glitazone has affinity for dehydrogenases, consistent with known binding preferences for related rhodanine cores. Both drugs bound ion channels and modulators, with implications in congestive heart failure, arrhythmia, and peripheral edema. Additional proteins involved in glucose homeostasis, synaptic transduction, and mitochondrial energy production were detected and potentially contribute to drug efficacy and cardiotoxicity.
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Affiliation(s)
- Brian R. Hoffmann
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Mohamed F. El-Mansy
- Chemical Proteomics Facility at Marquette, Department of Chemistry, Marquette University, Milwaukee, WI 53201
| | - Daniel S. Sem
- Chemical Proteomics Facility at Marquette, Department of Chemistry, Marquette University, Milwaukee, WI 53201
| | - Andrew S. Greene
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226
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Sutherland JP, McKinley B, Eckel RH. The metabolic syndrome and inflammation. Metab Syndr Relat Disord 2012; 2:82-104. [PMID: 18370640 DOI: 10.1089/met.2004.2.82] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The metabolic syndrome (MS) is a clustering of cardiovascular risk factors, with insulin resistance as a major feature. This syndrome has been variously defined, but generally consists of 3 or more of the following components: hyperglycemia, hypertension, hypertriglyceridemia, low HDL, and increased abdominal circumference and/or BMI at >30 kg/m(2). The WHO criteria require the presence of insulin resistance to make the diagnosis. The current review focuses particularly on the association of the MS and the proinflammatory state as well as treatment options to prevent the development of coronary heart disease (CHD). Chronic inflammation is frequently associated with the MS. Inflammatory markers that have been associated with MS include hs-CRP, TNF-alpha, fibrinogen, and IL-6, among others. The link between inflammation and the MS is not fully understood. One postulated mechanism is that these cytokines are released into the circulation by adipose tissue, stimulating hepatic CRP production. The prothrombotic molecule PAI-1 is also increased in the MS. Adiponectin, produced exclusively by adipocytes, is decreased in obesity. The association of these proinflammatory and prothrombotic markers with the MS is discussed in detail. The general goals of treatment of the MS are prevention of CHD events and diabetes if not already present. The approach to treatment of those with the MS should include lifestyle changes, including weight loss and exercise as well as appropriate pharmacological therapies. Certain medications, which may be used in persons with MS, have been shown to have beneficial effects on clinical outcome and/or anti-inflammatory effects.
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Melzer D, Osborne NJ, Henley WE, Cipelli R, Young A, Money C, McCormack P, Luben R, Khaw KT, Wareham NJ, Galloway TS. Urinary Bisphenol A Concentration and Risk of Future Coronary Artery Disease in Apparently Healthy Men and Women. Circulation 2012; 125:1482-90. [DOI: 10.1161/circulationaha.111.069153] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- David Melzer
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - Nicholas J. Osborne
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - William E. Henley
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - Riccardo Cipelli
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - Anita Young
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - Cathryn Money
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - Paul McCormack
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - Robert Luben
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - Kay-Tee Khaw
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - Nicholas J. Wareham
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
| | - Tamara S. Galloway
- From the Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter (D.M.); School of Biosciences, University of Exeter, Exeter (T.S.G., R.C.); School of Computing and Mathematics, University of Plymouth, Plymouth (W.E.H.); European Center for Environment and Human Health, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter (D.M., N.J.O., T.S.G.); Brixham Environmental Laboratory, Brixham (A.Y., C.M., P.M.); Medical Research Council
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Yu L, Jin X, Yang Y, Cui N, Jiang C. Rosiglitazone inhibits vascular KATP channels and coronary vasodilation produced by isoprenaline. Br J Pharmacol 2012; 164:2064-72. [PMID: 21671900 DOI: 10.1111/j.1476-5381.2011.01539.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Rosiglitazone is an anti-diabetic drug improving insulin sensitivity and glucose uptake in skeletal muscle and adipose tissues. However, several recent clinical trials suggest that rosiglitazone can increase the risk of cardiovascular ischaemia, although other studies failed to show such risks. Therefore, the effects of rosiglitazone on the coronary circulation and any potential vascular targets need to be elucidated. Here, we show that the vascular isoform of the ATP-sensitive K(+) (K(ATP) ) channel is inhibited by rosiglitazone, impairing physiological regulation of the coronary circulation. EXPERIMENTAL APPROACH The K(IR) 6.1/SUR2B channel was expressed in HEK293 cells and studied in whole-cell and inside-out patch configurations. The Langendorff heart preparation was used to evaluate rosiglitazone in the coronary circulation of wild-type (WT) and K(IR) 6.1-null (Kcnj8(-/-) ) mice. KEY RESULTS K(IR) 6.1/SUR2B channels in HEK cells were inhibited by rosiglitazone in a membrane-delimited manner. This effect was markedly enhanced by sub-micromolar concentrations of glibenclamide and the IC(50) for rosiglitazone fell to 2µM, a therapeutically achievable concentration. In the Langendorff heart preparation rosiglitazone inhibited, concentration-dependently, the coronary vasodilation induced by isoprenaline, without affecting basal coronary tone. Effects of rosiglitazone on coronary perfusion were attenuated by more than 50% in the Kcnj8(-/-) mice, supporting the involvement of K(ATP) channels in this effect of rosiglitazone on the coronary circulation. CONCLUSIONS AND IMPLICATIONS These results indicate that the vascular K(ATP) channel is one of the targets of rosiglitazone action, through which this drug may compromise coronary responses to circulating vasodilators and perhaps also to metabolic stress.
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Affiliation(s)
- Lei Yu
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA
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15
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Hussein AEAM, Omar NM, Sakr H, Elsamanoudy AZ, Shaheen D. Modulation of metabolic and cardiac dysfunctions by insulin sensitizers and angiotensin receptor blocker in rat model of type 2 diabetes mellitus. Can J Physiol Pharmacol 2012; 89:216-26. [PMID: 21423295 DOI: 10.1139/y11-012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The objective of this study was to investigate the modulation of metabolic dysfunctions, adiponectin levels, and cardiac dysfunctions of type 2 diabetes mellitus (T2DM) by a combination of the insulin sensitizer rosiglitazone and angiotensin receptor blocker telmisartan in an experimental rat model. Fifty male adult Sprague-Dawley rats were divided equally into 5 groups. Group I: fed normal chow; served as normal control group. Groups II-V: fed a high-fat diet (HFD) for 2 weeks, followed by injection of streptozotocin (STZ; 35 mg/kg) to create a model of T2DM. Group II: treated with vehicle. Group III: treated with rosiglitazone (4 mg/kg). Group IV: treated with telmisartan (5 mg/kg). Group V: treated with both agents. Untreated HFD-STZ rats showed elevated fasting blood glucose, insulin, homeostasis model assessment (HOMA) index, triglycerides (TGs), low-density lipoprotein cholesterol (LDL), and total serum cholesterol (TC), with a decrease in high-density lipoprotein cholesterol (HDL) and adiponectin levels (p < 0.001). Rosiglitazone exerted more improvement in all parameters than telmisartan did, and a combination of both did not augment the improvement further, except for TGs and adiponectin. For the isolated atrial study, a combination of rosiglitazone and telmisartan corrected the responses of the atria of HFD-STZ rats to the negative inotropic effect induced by adenosine better than either one did alone, whereas this combination, surprisingly, significantly attenuated the positive inotropic response to β-adrenoreceptor and α-adrenoreceptor agonists. In conclusion, rosiglitazone significantly improved the metabolic and cardiac dysfunctions in T2DM. Moreover, a combination of rosiglitazone and telmisartan offered more improvement in serum TGs and adiponectin, and restored the atrial inotropic response to adenosine. Surprisingly, this combination significantly attenuates the positive inotropic response to α1-adrenoreceptor and β-adrenoreceptor agonists.
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16
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Hussein AAM, Abdel-Aziz A, Gabr M, Hemmaid KZ. Myocardial and metabolic dysfunction in type 2 diabetic rats: impact of ghrelin. Can J Physiol Pharmacol 2012; 90:99-111. [DOI: 10.1139/y11-103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Diabetes mellitus (DM) is commonly associated with metabolic and cardiac dysfunctions. The aim of this study was to examine the effect of ghrelin on metabolic and cardiac dysfunctions in a type-2 diabetes mellitus (T2DM) rat model. For this, 48 male adult Sprague–Dawley rats were divided equally into 4 groups: Group I, fed normal chow, served as normal control group; Groups II–IV, were fed a high-fat diet for 2 weeks followed by injection of streptozotocin (STZ) (35 mg/kg body mass) to create a model of T2DM; Group II, were not treated; Group III, were treated with the vehicle (saline); Group IV, were treated with ghrelin (40 µg/kg body mass) twice daily for 10 days. The untreated diabetic rats showed a significant increase in serum fasting blood glucose, insulin homeostasis model assessment (HOMA) index, triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), total serum cholesterol (TC), and body mass, with a decrease in high-density lipoprotein cholesterol (HDL-C) (p < 0.05). Hearts isolated from diabetic rats showed a significant increase in myocardial fat content, a significant decrease in GLUT4, and an increase in acyl-CoA oxidase enzyme mRNA (p < 0.05). Ghrelin administration for 10 days caused a significant improvement in lipid profile, HOMA index, and body mass, and significantly corrected the myocardial mass, significantly reduced the fat content of the myocardium, significantly increased GLUT4, and decreased acyl CoA oxidase mRNA (p < 0.05). Thus, ghrelin improves both the metabolic functions and the disturbed energy metabolism in the cardiac muscle of obese diabetic rats.
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Affiliation(s)
| | - Azza Abdel-Aziz
- Department of Pathology, Mansoura Faculty of Medicine, Mansoura, Egypt
| | - Mahmoud Gabr
- Urology and Nephrology Center, Mansoura University, Mansoura, Egypt
| | - Kamel Z. Hemmaid
- Department of Zoology, Faculty of Science, Zagazig University, Egypt
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17
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Majeed Y, Bahnasi Y, Seymour VAL, Wilson LA, Milligan CJ, Agarwal AK, Sukumar P, Naylor J, Beech DJ. Rapid and contrasting effects of rosiglitazone on transient receptor potential TRPM3 and TRPC5 channels. Mol Pharmacol 2011; 79:1023-30. [PMID: 21406603 DOI: 10.1124/mol.110.069922] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The aim of this study was to generate new insight into chemical regulation of transient receptor potential (TRP) channels with relevance to glucose homeostasis and the metabolic syndrome. Human TRP melastatin 2 (TRPM2), TRPM3, and TRP canonical 5 (TRPC5) were conditionally overexpressed in human embryonic kidney 293 cells and studied by using calcium-measurement and patch-clamp techniques. Rosiglitazone and other peroxisome proliferator-activated receptor-γ (PPAR-γ) agonists were investigated. TRPM2 was unaffected by rosiglitazone at concentrations up to 10 μM but was inhibited completely at higher concentrations (IC(50), ∼22.5 μM). TRPM3 was more potently inhibited, with effects occurring in a biphasic concentration-dependent manner such that there was approximately 20% inhibition at low concentrations (0.1-1 μM) and full inhibition at higher concentrations (IC(50), 5-10 μM). PPAR-γ antagonism by 2-chloro-5-nitrobenzanilide (GW9662) did not prevent inhibition of TRPM3 by rosiglitazone. TRPC5 was strongly stimulated by rosiglitazone at concentrations of ≥10 μM (EC(50), ∼30 μM). Effects on TRPM3 and TRPC5 occurred rapidly and reversibly. Troglitazone and pioglitazone inhibited TRPM3 (IC(50), 12 μM) but lacked effect on TRPC5, suggesting no relevance of PPAR-γ or the thiazolidinedione moiety to rosiglitazone stimulation of TRPC5. A rosiglitazone-related but nonthiazolidinedione PPAR-γ agonist, N-(2-benzoylphenyl)-O-[2-(methyl-2-pyridinylamino)ethyl]-l-tyrosine (GW1929), was a weak stimulator of TRPM3 and TRPC5. The natural PPAR-γ agonist 15-deoxy prostaglandin J(2), had no effect on TRPM3 or TRPC5. The data suggest that rosiglitazone contains chemical moieties that rapidly, strongly, and differentially modulate TRP channels independently of PPAR-γ, potentially contributing to biological consequences of the agent and providing the basis for novel TRP channel pharmacology.
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Affiliation(s)
- Yasser Majeed
- Multidisciplinary Cardiovascular Research Centre and Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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18
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Phelps LE, Peuler JD. Evidence of direct smooth muscle relaxant effects of the fibrate gemfibrozil. J Smooth Muscle Res 2010; 46:125-42. [PMID: 20647690 DOI: 10.1540/jsmr.46.125] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Fibrates are commonly employed to treat abnormal lipid metabolism via their unique ability to stimulate peroxisome proliferator-activated receptor alpha (PPARalpha). Interestingly, they also decrease systemic arterial pressure, despite recent evidence that PPAR alpha may contribute to expression of renin and related hypertension. Yet, mechanisms responsible for their potential antihypertensive activity remain unresolved. Rapid decreases in arterial pressure following bolus intravenous injections of bezafibrate strongly suggest they may relax arterial smooth muscle directly. But since bezafibrate is highly susceptible to photodegradation in aqueous media, it has never been critically tested for this possibility in vitro with isolated arterial smooth muscle preparations. Accordingly, we tested gemfibrozil which is resistant to photodegradation. We examined it over a therapeutically-relevant range (50-400 microM) for both acute and delayed relaxant effects on contractions of the isolated rat tail artery; contractions induced by either depolarizing its smooth muscle cell membranes with high potassium or stimulating its membrane-bound receptors with norepinephrine and arginine-vasopressin. We also examined these same gemfibrozil levels for effects on spontaneously-occurring phasic rhythmic contractile activity, typically not seen in arteries under in vitro conditions but commonly exhibited by smooth muscle of uterus, duodenum and bladder. We found that gemfibrozil significantly relaxed all induced forms of contraction in the rat tail artery, acutely at the higher test levels and after a delay of a few hours at the lower test levels. The highest test level of gemfibrozil (400 microM) also completely abolished spontaneously-occurring contractile activity of the isolated uterus and duodenum and markedly suppressed it in the bladder. This is the first evidence that a fibrate drug can directly relax smooth muscle contractions, either induced by various contractile agents or spontaneously-occurring. These findings are particularly relevant to both the recently renewed concern over the impact of fibrates on hypertension and a new understanding of their gastrointestinal side effects.
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Affiliation(s)
- Laura E Phelps
- Department of Pharmacology, Midwestern University, IL 60515, USA
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19
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Venegas-Pont M, Manigrasso MB, Grifoni SC, LaMarca BB, Maric C, Racusen LC, Glover PH, Jones AV, Drummond HA, Ryan MJ. Tumor necrosis factor-alpha antagonist etanercept decreases blood pressure and protects the kidney in a mouse model of systemic lupus erythematosus. Hypertension 2010; 56:643-9. [PMID: 20696988 DOI: 10.1161/hypertensionaha.110.157685] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chronic inflammation has been implicated in the pathology of hypertension; however, the role for specific cytokines remains unclear. We tested whether tumor necrosis factor-α blockade with etanercept (Etan) reduces mean arterial pressure in a female mouse model of systemic lupus erythematosus (SLE). SLE is a chronic inflammatory disorder with prevalent hypertension. Thirty-week-old SLE (NZBWF1) and control mice (NZW/LacJ) received Etan (0.8 mg/kg SC weekly) for 4 weeks or vehicle. Mean arterial pressure (in millimeters of mercury) was increased in SLE mice (150±5 versus 113±5 in controls; P<0.05) and was lower in Etan-treated SLE mice (132±3) but not controls (117±5). Albuminuria (in micrograms per milligram of creatinine) was elevated in SLE mice (28 742±9032 versus 1075±883; P<0.05) and was lower in Etan-treated SLE mice (8154±3899) but not control animals (783±226). Glomerulosclerosis (in percentage of glomeruli) was evident in SLE mice (2.5±1.6 versus 0.0±0.0 in controls; P<0.05) and was ameliorated in Etan-treated SLE mice (0.1±0.1). Renal cortex CD68(+) cell staining (in percentage of area) was elevated in SLE mice (4.75±0.80 versus 0.79±0.12 in controls; P<0.05) and was lower in Etan-treated SLE mice (2.28±0.32) but not controls (1.43±0.25). Renal cortex NADPH oxidase activity (relative light units per milligram of protein) was higher in SLE mice compared with controls (10 718±1276 versus 7584±229; P<0.05) and lowered in Etan-treated SLE mice (6645±490). Renal cortex nuclear factor κB (phosphorylated and nonphosphorylated) was increased in SLE mice compared with controls and lower in Etan-treated SLE mice. These data suggest that TNF-α mechanistically contributes to the development of hypertension in a chronic inflammatory disease through increased renal nuclear factor κB, oxidative stress, and inflammation.
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Affiliation(s)
- Marcia Venegas-Pont
- Department of Physiology and Biophysics, Center for Excellence in Cardiovascular Renal Research, University of Mississippi Medical Center, 2500 North State St, Jackson, MS 39216-4505, USA
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20
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Irat AM, Aslamaci S, Karasu C, Ari N. Alteration of vascular reactivity in diabetic human mammary artery and the effects of thiazolidinediones. J Pharm Pharmacol 2010; 58:1647-53. [PMID: 17331329 DOI: 10.1211/jpp.58.12.0012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Vascular reactivity was investigated in endothelium-denuded human internal mammary artery (IMA) rings from type 2 diabetic patients. It was also investigated whether insulin sensitizer thiazolidinedione drugs, pioglitazone and rosiglitazone, can directly affect the reactivity of IMA. Using organ bath techniques, cumulative concentration-response curves to phenylephrine (PE), KCl, cromakalim (CRO) and sodium nitroprusside (SNP) were constructed in diabetic and non-diabetic IMA rings. Means of maximal responses (% Emax) and pEC50 values (sensitivity) were compared. Emax values and the sensitivity to PE and KCl were increased while KATP-channel-mediated relaxations were reduced significantly in diabetic rings compared with non-diabetic rings (n = 5–12, P < 0.05). No changes were observed for SNP responses (n = 5, P > 0.05). Incubations with pioglitazone (1 and 10 μM) and rosiglitazone (1 and 20 μM), for 30 min, did not affect KATP-channel-mediated relaxations (n = 5 each, P > 0.05). Pioglitazone partly inhibited pre-contractions of PE and KCl at 10 μM, rosiglitazone did not. Vascular dysfunction observed in diabetic IMA may be of specific importance since they are widely used as coronary bypass material. Thiazolidinedione drugs may not worsen arterial dilatation through KATP channels in ischaemic or hypoxic insults in diabetic patients who are prone to such conditions. Pioglitazone has vasorelaxant property in the grafts.
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Affiliation(s)
- Ali Murat Irat
- Department of Pharmacology, University of Ankara, Tandoğan 06100, Ankara, Turkey
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21
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Ketsawatsomkron P, Pelham CJ, Groh S, Keen HL, Faraci FM, Sigmund CD. Does peroxisome proliferator-activated receptor-gamma (PPAR gamma) protect from hypertension directly through effects in the vasculature? J Biol Chem 2010; 285:9311-9316. [PMID: 20129921 DOI: 10.1074/jbc.r109.025031] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Peroxisome proliferator-activated receptor-gamma (PPAR gamma) is a ligand-activated transcription factor of the nuclear hormone receptor superfamily. Increasing evidence suggests that PPAR gamma is involved in the regulation of vascular function and blood pressure in addition to its well recognized role in metabolism. Thiazolidinediones, PPAR gamma agonists, lower blood pressure and have protective vascular effects through largely unknown mechanisms. In contrast, loss-of-function dominant-negative mutations in human PPAR gamma cause insulin resistance and severe early onset hypertension. Recent studies using genetically manipulated mouse models have begun to specifically address the importance of PPAR gamma in the vasculature. In this minireview, evidence for a protective role of PPAR gamma in the endothelium and vascular smooth muscle, derived largely from studies of genetically manipulated mice, will be discussed.
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Affiliation(s)
- Pimonrat Ketsawatsomkron
- Department of Internal Medicine, Center on Functional Genomics of Hypertension, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Christopher J Pelham
- Department of Internal Medicine, Center on Functional Genomics of Hypertension, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Séverine Groh
- Department of Internal Medicine, Center on Functional Genomics of Hypertension, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Henry L Keen
- Department of Internal Medicine, Center on Functional Genomics of Hypertension, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Frank M Faraci
- Department of Internal Medicine, Center on Functional Genomics of Hypertension, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Curt D Sigmund
- Department of Internal Medicine, Center on Functional Genomics of Hypertension, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242.
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Melzer D, Rice NE, Lewis C, Henley WE, Galloway TS. Association of urinary bisphenol a concentration with heart disease: evidence from NHANES 2003/06. PLoS One 2010; 5:e8673. [PMID: 20084273 PMCID: PMC2800195 DOI: 10.1371/journal.pone.0008673] [Citation(s) in RCA: 375] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/03/2009] [Indexed: 11/30/2022] Open
Abstract
Background Bisphenol A (BPA) is a high production volume chemical widely used in food and drinks packaging. Associations have previously been reported between urinary BPA concentrations and heart disease, diabetes and liver enzymes in adult participants of the National Health and Nutrition Examination Survey (NHANES) 2003/04. We aimed to estimate associations between urinary BPA concentrations and health measures in NHANES 2005/06 and in data pooled across collection years. Methodology and Findings A cross-sectional analysis of NHANES: subjects were n = 1455 (2003/04) and n = 1493 (2005/06) adults aged 18–74 years, representative of the general adult population of the United States. Regression models were adjusted for age, sex, race/ethnicity, education, income, smoking, BMI, waist circumference, and urinary creatinine concentration. Main outcomes were reported diagnoses of heart attack, coronary heart disease, angina and diabetes and serum liver enzyme levels. Urinary BPA concentrations in 2005/06 (geometric mean 1.79 ng/ml, 95% CI: 1.64 to 1.96) were lower than in 2003/04 (2.49 ng/ml, CI: 2.20 to 2.83, difference p-value = 0.00002). Higher BPA concentrations were associated with coronary heart disease in 2005/06 (OR per z-score increase in BPA = 1.33, 95%CI: 1.01 to 1.75, p = 0.043) and in pooled data (OR = 1.42, CI: 1.17 to 1.72, p = 0.001). Associations with diabetes did not reach significance in 2005/06, but pooled estimates remained significant (OR = 1.24, CI: 1.10 to 1.40, p = 0.001). There was no overall association with gamma glutamyl transferase concentrations, but pooled associations with alkaline phosphatase and lactate dehydrogenase remained significant. Conclusions Higher BPA exposure, reflected in higher urinary concentrations of BPA, is consistently associated with reported heart disease in the general adult population of the USA. Studies to clarify the mechanisms of these associations are urgently needed.
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Affiliation(s)
- David Melzer
- Epidemiology and Public Health Group, Peninsula Medical School, University of Exeter, Exeter, United Kingdom.
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Effects of chronic PPAR-agonist treatment on cardiac structure and function, blood pressure, and kidney in healthy sprague-dawley rats. PPAR Res 2009; 2009:237865. [PMID: 19536351 PMCID: PMC2696219 DOI: 10.1155/2009/237865] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 02/25/2009] [Accepted: 03/23/2009] [Indexed: 01/02/2023] Open
Abstract
PPAR-γ agonists have been associated with heart failure (HF) in diabetic patients. These incidences have been reported mostly in patient populations who were at high risk for HF or had pre-existing impaired cardiovascular function. However, whether there are similar effects of these agents in subjects with no or reduced cardiovascular pathophysiology is not clear. In this study, the effects of chronic treatment with PD168, a potent peroxisome proliferator activated receptor (PPAR) subtype-γ agonist with weak activity at PPAR-α, and rosiglitazone (RGZ), a less potent PPAR-γ agonist with no PPAR-α activity, were evaluated on the cardiovascular-renal system in healthy male Sprague-Dawley (SD) rats by serial echocardiography and radiotelemetry. Rats were treated with vehicle (VEH), PD168, @ 10 or 50 mg/kg.bw/day (PD-10 or PD-50, resp.) or RGZ @ 180 mg/kg.bw/day for 28 days (n = 10/group). Relative to VEH, RGZ, and both doses of PD168 resulted in a significant fall in blood pressure. Furthermore, RGZ and PD168 increased plasma volume (% increase from baseline) 18%, 22%, and 48% for RGZ, PD-10, and PD-50, respectively. PD168 and RGZ significantly increased urinary aldosterone excretion and heart-to-body weight ratio relative to VEH. In addition, PD168 significantly decreased (10-16%) cardiac ejection fraction (EF) and increased left ventricular area (LVA) in systole (s) and diastole (d) in PD-10 and -50 rats. RGZ significantly increased LVAd; however, it did not affect EF relative to VEH. In conclusion, chronic PPAR-γ therapy may predispose the cardiorenal system to a potential sequela of structural and/or functional changes that may be deleterious with regard to morbidity and mortality.
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Nofziger C, Brown KK, Smith CD, Harrington W, Murray D, Bisi J, Ashton TT, Maurio FP, Kalsi K, West TA, Baines D, Blazer-Yost BL. PPARgamma agonists inhibit vasopressin-mediated anion transport in the MDCK-C7 cell line. Am J Physiol Renal Physiol 2009; 297:F55-62. [PMID: 19403648 DOI: 10.1152/ajprenal.00090.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
PPARgamma agonists are synthetic ligands for the peroxisome proliferator-activated receptor-gamma (PPARgamma). These agents have insulin-sensitizing properties but can cause fluid retention, thereby limiting their usefulness in patients at risk for cardiovascular disease. The side effect etiology is unknown, but the nature of presentation suggests modulation of renal salt and water homeostasis. In a well-characterized cell culture model of the principal cell type [Madin-Darby canine kidney (MDCK)-C7], PPARgamma agonists inhibit vasopressin-stimulated Cl(-) secretion with agonist dose-response relationships that mirror receptor transactivation profiles. Analyses of the components of the vasopressin-stimulated intracellular signaling pathway indicated no PPARgamma agonist-induced changes in basolateral membrane conductances, intracellular cAMP, protein kinase A, or total cellular adenine nucleotides. The PPARgamma agonist-induced decrease in anion secretion is the result of decreased mRNA of the final effector in the pathway, the apically located cystic fibrosis transmembrane regulator (CFTR). These data showing that CFTR is a target for PPARgamma agonists may provide new insights into the physiology of PPARgamma agonist-induced fluid retention.
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Affiliation(s)
- Charity Nofziger
- Department of Biology, Indiana University-Purdue University at Indianapolis, Indianapolis, Indiana 46202, USA
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Lu L, Reiter MJ, Xu Y, Chicco A, Greyson CR, Schwartz GG. Thiazolidinedione drugs block cardiac KATP channels and may increase propensity for ischaemic ventricular fibrillation in pigs. Diabetologia 2008; 51:675-85. [PMID: 18251006 PMCID: PMC3633423 DOI: 10.1007/s00125-008-0924-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Accepted: 12/04/2007] [Indexed: 01/25/2023]
Abstract
AIMS/HYPOTHESIS Opening of ATP-sensitive potassium (K(ATP)) channels during myocardial ischaemia shortens action potential duration and is believed to be an adaptive, energy-sparing response. Thiazolidinedione drugs block K(ATP) channels in non-cardiac cells in vitro. This study determined whether thiazolidinedione drugs block cardiac K(ATP) channels in vivo. METHODS Experiments in 68 anaesthetised pigs determined: (1) effects of inert vehicle, troglitazone (10 mg/kg i.v.) or rosiglitazone (0.1 or 1.0 mg/kg i.v.) on epicardial monophasic action potential (MAP) during 90 min low-flow ischaemia; (2) effects of troglitazone, rosiglitazone or pioglitazone (1 mg/kg i.v.) on response of MAP to intracoronary infusion of a K(ATP) channel opener, levcromakalim; and (3) effects of inert vehicle, rosiglitazone (1 mg/kg i.v.) or the sarcolemmal K(ATP) blocker HMR-1098 on time to onset of ventricular fibrillation following complete coronary occlusion. RESULTS With vehicle, epicardial MAP shortened by 44+/-9 ms during ischaemia. This effect was attenuated to 12+/-8 ms with troglitazone and 6+/-6 ms with rosiglitazone (p<0.01 for both vs vehicle), suggesting K(ATP) blockade. Intracoronary levcromakalim shortened MAP by 38+/-10 ms, an effect attenuated to 12+/-8, 13+/-4 and 9+/-5 ms during co-treatment with troglitazone, rosiglitazone or pioglitazone (p<0.05 for each), confirming K(ATP) blockade. During coronary occlusion, median time to ventricular fibrillation was 29 min in pigs treated with vehicle and 6 min in pigs treated with rosiglitazone or HMR-1098 (p<0.05 for both vs vehicle), indicating that K(ATP) blockade promotes ischaemic ventricular fibrillation in this model. CONCLUSIONS/INTERPRETATION Thiazolidinedione drugs block cardiac K(ATP) channels at clinically relevant doses and promote onset of ventricular fibrillation during severe ischaemia.
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Affiliation(s)
- L Lu
- VA Medical Center and University of Colorado Health Sciences Center, Denver, CO 80220, USA
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Nomura H, Yamawaki H, Mukohda M, Okada M, Hara Y. Mechanisms Underlying Pioglitazone-Mediated Relaxation in Isolated Blood Vessel. J Pharmacol Sci 2008; 108:258-65. [PMID: 18987433 DOI: 10.1254/jphs.08117fp] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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27
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Effects of rosiglitazone on altered electrical left ventricular papillary muscle activities of diabetic rat. Naunyn Schmiedebergs Arch Pharmacol 2007; 376:415-21. [DOI: 10.1007/s00210-007-0234-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 11/23/2007] [Indexed: 10/22/2022]
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28
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Ahn HS, Kim SE, Jang HJ, Kim MJ, Rhie DJ, Yoon SH, Jo YH, Kim MS, Sung KW, Kim SY, Hahn SJ. Open channel block of Kv1.3 by rosiglitazone and troglitazone: Kv1.3 as the pharmacological target for rosiglitazone. Naunyn Schmiedebergs Arch Pharmacol 2006; 374:305-9. [PMID: 17119927 DOI: 10.1007/s00210-006-0118-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Accepted: 10/27/2006] [Indexed: 10/23/2022]
Abstract
The effects of rosiglitazone and troglitazone were examined on cloned Kv1.3 channels stably expressed in Chinese hamster ovary cells using the whole-cell configuration of the patch-clamp technique. Rosiglitazone decreased the Kv1.3 currents and accelerated the decay rate of current inactivation in a concentration-dependent manner with an IC(50) of 18.6 microM. These effects were reversible after washout of the drug. Troglitazone caused the block of Kv1.3 with a similar pattern but was five times more potent than rosiglitazone with an IC(50) of 3.5 microM. The block of Kv1.3 by rosiglitazone and troglitazone was voltage-dependent at a membrane potential coinciding with the activation of the channels. Both drugs decreased the tail current amplitude and slowed the deactivation process of Kv1.3, resulting in a tail crossover phenomenon. These results indicate that rosiglitazone and troglitazone block the open state of Kv1.3 channels, suggesting that it is an important pharmacological target for rosiglitazone as a potent blocker of Kv1.3 channels.
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Affiliation(s)
- Hye Sook Ahn
- Department of Physiology, Medical Research Center, College of Medicine, The Catholic University of Korea, 505 Banpo-Dong, Socho-Gu, Seoul, South Korea
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Cai Q, Zhu ZL, Fan XL. Whole-cell recordings of calcium and potassium currents in acutely isolated smooth muscle cells. World J Gastroenterol 2006; 12:4086-8. [PMID: 16810766 PMCID: PMC4087728 DOI: 10.3748/wjg.v12.i25.4086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To record calcium and potassium currents in acutely isolated smooth muscle cells of mesenteric arterial branches in rats.
METHODS: Smooth muscle cells were freshly isolated by collagenase digest and mechanical trituration with polished pipettes. Patch clamp technique in whole-cell mode was employed to record calcium and potassium currents.
RESULTS: The procedure dissociated smooth muscle cells without impairing the electrophysiological characteristics of the cells. The voltage-gated Ca2+ and potassium currents were successfully recorded using whole-cell patch clamp configuration.
CONCLUSION: The method dissociates smooth muscle cells from rat mesenteric arterial branches. Voltage-gated channel currents can be recorded in this preparation.
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Affiliation(s)
- Qing Cai
- Department of Physiology and Pathophysiology, Medical School of Xi'an Jiaotong University, Xi'an 710061, Shaanxi Province, China
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30
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Halabi CM, Sigmund CD. Peroxisome proliferator-activated receptor-gamma and its agonists in hypertension and atherosclerosis : mechanisms and clinical implications. Am J Cardiovasc Drugs 2006; 5:389-98. [PMID: 16259527 DOI: 10.2165/00129784-200505060-00006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Cardiovascular diseases are the leading cause of morbidity and mortality in the US. Proper management and/or prevention of atherosclerosis and hypertension, two complex and chronic disorders, would significantly reduce the risk for cardiovascular events such as myocardial infarction and stroke, but this requires an understanding of the mechanisms underlying their development and progression. Whereas a great deal has been learned and applied toward the management of these disorders, especially hypertension, morbidity and mortality remains unacceptably high, most likely because there are disease-causing mechanisms that have yet to be fully recognized. Understanding these disease mechanisms is necessary so that novel management strategies can be developed. One of these novel mechanisms centers on peroxisome proliferator-activated receptor (PPAR)-gamma. PPAR-gamma is a member of the nuclear receptor superfamily of ligand-activated transcription factors known to play a role in glucose homeostasis and adipocyte differentiation and, more recently, has been shown to have anti-inflammatory, antiatherogenic, and antihypertensive effects. Thiazolidinediones, a class of drugs used in the treatment of type 2 diabetes mellitus, are high-affinity ligands for PPAR-gamma. In this review, the anti-inflammatory, anti-atherosclerotic, and anti-hypertensive mechanisms by which PPAR-gamma and its agonists are thought to exert protective effects on the cardiovascular system are discussed. Ongoing clinical trials using PPAR-gamma activators for the management of cardiovascular diseases, especially in patients with type 2 diabetes mellitus, are summarized.
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Affiliation(s)
- Carmen M Halabi
- Medical Scientist Training Program, University of Iowa, Iowa City, Iowa 52242, USA
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31
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Leung GPH, Man RYK, Tse CM. Effect of thiazolidinediones on equilibrative nucleoside transporter-1 in human aortic smooth muscle cells. Biochem Pharmacol 2005; 70:355-62. [PMID: 15963471 DOI: 10.1016/j.bcp.2005.05.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Revised: 05/10/2005] [Accepted: 05/10/2005] [Indexed: 10/25/2022]
Abstract
Thiazolidinediones are a new class of anti-diabetic agents which increase insulin sensitivity by binding to the peroxisome proliferator-activated receptor gamma (PPAR(gamma)) and stimulating the expression of insulin-responsive genes involved in glucose and lipid metabolism. These drugs also have vasodilatory and anti-proliferative effects on vascular smooth muscle cells. However the mechanisms for these actions are not fully understood. Adenosine is a vasodilator and a substrate of equilibrative nucleoside transporters (ENT). The present study studied the effects of three thiazolidinediones, troglitazone, pioglitazone and ciglitazone, on ENT1 in the human aortic smooth muscle cells (HASMCs). Although incubating HASMCs for 48h with thiazolidinediones had no effect on ENT1 mRNA and protein levels, troglitazone acutely inhibited [3H]adenosine uptake and [3H]NBMPR binding of HASMCs with IC50 values of 2.35+/-0.35 and 3.99+/-0.57microM, respectively. The effect of troglitazone on ENT1 was PPAR(gamma)-independent and kinetic studies revealed that troglitazone was a competitive inhibitor of ENT1. In contrast, pioglitazone and ciglitazone had minimal effects on [3H]adenosine uptake by HASMCs. Troglitazone differs from pioglitazone and ciglitazone in that its side-chain contains a Vitamin E moiety. The difference in structure of troglitazone did not account for its inhibitory effect on ENT1 because Vitamin E did not inhibit [3H]adenosine uptake by HASMCs. Using the nucleoside transporter deficient PK15NTD cells stably expressing ENT1 and ENT2, it was found that troglitazone inhibited ENT1 but had no effect on ENT2. From these results, it is suggested that troglitazone may enhance the vasodilatory effect of adenosine by inhibiting ENT1. Pharmacologically, troglitazone is a novel inhibitor of ENT1.
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Affiliation(s)
- George P H Leung
- Department of Pharmacology, The University of Hong Kong, Hong Kong.
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32
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Heppner TJ, Bonev AD, Eckman DM, Gomez MF, Petkov GV, Nelson MT. Novel PPARγ Agonists GI 262570, GW 7845, GW 1929, and Pioglitazone Decrease Calcium Channel Function and Myogenic Tone in Rat Mesenteric Arteries. Pharmacology 2004; 73:15-22. [PMID: 15452359 DOI: 10.1159/000081070] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Accepted: 05/21/2004] [Indexed: 11/19/2022]
Abstract
Novel non-thiazolidinedione, tyrosine-derived peroxisome proliferator-activated receptor gamma agonists, GI 262570, GW 7845, GW 1929, developed by GlaxoSmithKline (GSK) along with pioglitazone and nisoldipine, were studied on currents through L-type voltage-dependent calcium channels (VDCC) in freshly isolated smooth muscle cells from mesenteric arteries, and on the diameter of pressurized mesenteric arteries in vitro. Using Ba2+ (10 mmol/l) as the charge carrier through VDCC, the half-inhibition constants (IC50) for GI 262570, GW 7845, GW 1929, and pioglitazone were 2.0 +/- 0.5, 3.0 +/- 0.5, 5.0 +/- 0.7, and 10.0 +/- 0.8 mumol/l, respectively. For arterial diameter measurements the IC50 values for GI 262570, GW 7845, GW 1929, and pioglitazone were 2.4, 4.1, 6.3, and 13.9 mumol/l, respectively. Each GSK compound and pioglitazone was effective at inhibiting VDCC and relaxing pressurized arteries, suggesting that the vasodilation of resistance arteries could be explained by the inhibition of calcium entry through VDCC.
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Affiliation(s)
- Thomas J Heppner
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, VT 05406-0068, USA
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Ryan MJ, Didion SP, Mathur S, Faraci FM, Sigmund CD. PPAR(gamma) agonist rosiglitazone improves vascular function and lowers blood pressure in hypertensive transgenic mice. Hypertension 2004; 43:661-6. [PMID: 14744930 DOI: 10.1161/01.hyp.0000116303.71408.c2] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The peroxisome proliferator activated receptor (PPARgamma) agonist rosiglitazone has been reported to yield cardiovascular benefits in patients by a mechanism that is not completely understood. We tested whether oral rosiglitazone (25 mg/kg per day, 21 days) treatment improves blood pressure and vascular function in a transgenic mouse expressing both human renin and human angiotensinogen transgenes (R(+)A(+)). Rosiglitazone decreased systolic (138+/-5 versus 128+/-5 mm Hg) and mean blood pressure (145+/-5 versus 126+/-7 mm Hg) of R(+)A(+) mice as measured by tail-cuff and indwelling carotid catheters, respectively. Relaxation of carotid arteries to acetylcholine and authentic nitric oxide, but not papaverine, was impaired in R(+)A(+) mice when compared with littermate controls (RA(-)). There were no effects of rosiglitazone on RA(-) mice; however, relaxation to acetylcholine (49+/-10 versus 82+/-9% at 100 micromol/L) and nitric oxide (51+/-11 versus 72+/-6% at 10 micromol/L) was significantly improved in treated R(+)A(+) mice. Rosiglitazone treatment of R(+)A(+) mice did not alter the expression of genes, including endothelial nitric oxide synthase (eNOS), angiotensin 1 receptors, and preproendothelin-1, nor did it alter the levels of eNOS or soluble guanylyl cyclase protein. In separate studies, carotid arteries from R(+)A(+) and RA(-) mice relaxed in a concentration-dependent manner to rosiglitazone, suggesting possible PPARgamma-independent effects in the vasculature. This response was not inhibited with the nitric oxide synthase inhibitor N(omega)-nitro-l-arginine methyl ester (200 micromol/L) or the PPARgamma antagonist bisphenol A diglycidyl ether; 4,4'-isopropylidenediphenol diglycidyl ether (100 micromol/L). These data suggest that in addition to potential genomic regulation caused by PPARgamma activation, the direct effect of rosiglitazone in blood vessels may contribute to the improved blood pressure and vessel function.
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Affiliation(s)
- Michael J Ryan
- Ph.D. Professor, Department of Internal Medicine, 3181 MERF, University of Iowa, Department of Internal Medicine Iowa City, IA 52242, USA.
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Abstract
In patients with type 2 diabetes mellitus, the traditional method of initiating therapy with a sulfonylurea and increasing the dosage until maximum levels are reached before adding an insulin-sensitizing agent has persisted and should be re-evaluated. Similarly, the current practice of starting therapy with one agent and increasing to maximum dosage before adding a second agent, rather than starting with combination therapy, also needs to be addressed. There is much evidence to suggest that initiating therapy with lower doses of two agents that have complementary effects can increase the overall efficacy and decrease the incidence of adverse effects. Clearly, there is a need for a paradigm shift away from the traditional approach of therapy using insulin secretagogues to a more pathophysiologic approach using an insulin-sensitizing agent, such as the thiazolidinediones. The thiazolidinediones have been shown to reduce insulin resistance, improve the ability of beta-cells to produce insulin, and decrease cardiac risk factors. By reducing insulin resistance, improving glycemic control, and preserving beta-cell function with a thiazolidinedione early in the course of therapy, it is likely that durable glycemic control will be achieved and both microvascular and macrovascular complications may be reduced. Furthermore, early use of an insulin-sensitizing agent either alone or incombination is expected to improve both acute and long-term outcomes in patients with type 2 diabetes.
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Affiliation(s)
- David S H Bell
- School of Medicine, Department of Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA.
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Abstract
Nearly 90% of patients with hypertension and diabetes mellitus do not reach the recommended systolic blood pressure goal of <130 mm Hg. Consequently, the risk of cardiovascular and renal complications remains significant in this patient population. Study results suggest that initiating therapy with inhibitors of the renin-angiotensin system and adding diuretics may be useful in reducing arterial pressure to levels <130 mm Hg and may attenuate the progression of nephropathy. Recently, numerous studies have also found that the thiazolidinediones (TZDs) may improve insulin resistance and exert beneficial vascular effects in patients with type 2 diabetes. The TZDs have a range of vascular benefits, including mediating vasorelaxation, inhibiting angiogenesis, and improving inflammation. These findings have been associated with reduction in blood pressure and prevention of microalbuminuria. In patients with type 2 diabetes, early use of TZDs may be beneficial in both achieving glucose control and reducing the development or worsening of microalbuminuria or hypertension.
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Affiliation(s)
- George L Bakris
- Hypertension Clinical Research Center, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA
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Abstract
There is a high frequency of heart failure (HF) accompanied by an increased mortality risk for patients with diabetes. The poor prognosis of these patients has been explained by an underlying diabetic cardiomyopathy exacerbated by hypertension and ischemic heart disease. In these patients, activation of the sympathetic nervous system results in increased myocardial utilization of fatty acids and induction of fetal gene programs, decreasing myocardial function. Activation of the renin-angiotensin system results in myocardial remodeling. It is imperative for physicians to intercede early to stop the progression of HF, yet at least half of patients with left ventricular dysfunction remain undiagnosed and untreated until advanced disease causes disability. This delay is largely because of the asymptomatic nature of early HF, which necessitates more aggressive assessment of HF risk factors and early clinical signs. Utilization of beta-blockade, ACE inhibitors, or possibly angiotensin receptor blockers is essential in preventing remodeling with its associated decline in ventricular function. beta-Blockers not only prevent, but may also reverse, cardiac remodeling. Glycemic control may also play an important role in the therapy of diabetic HF. The adverse metabolic side effects that have been associated with beta-adrenergic inhibitors in the diabetic patient may be circumvented by use of a third-generation beta-blocker. Prophylactic utilization of ACE inhibitors and beta-blockers to avoid, rather than await, the need to treat HF should be considered in high-risk diabetic patients.
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Affiliation(s)
- David S H Bell
- Department of Medicine, University of Alabama at Birmingham, USA.
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Xu Y, Lu L, Greyson C, Lee J, Gen M, Kinugawa K, Long CS, Schwartz GG. Deleterious effects of acute treatment with a peroxisome proliferator-activated receptor-gamma activator in myocardial ischemia and reperfusion in pigs. Diabetes 2003; 52:1187-94. [PMID: 12716751 PMCID: PMC3633427 DOI: 10.2337/diabetes.52.5.1187] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Thiazolidinediones exert electrophysiologic effects in noncardiac cells in vitro, but to date there have been no reports of effects on cardiac rhythm. We previously demonstrated that chronic pretreatment with a thiazolidinedione peroxisome proliferator-activated receptor (PPAR)-gamma activator, troglitazone, improves recovery of left ventricular (LV) function and substrate metabolism after ischemia and reperfusion, without causing arrhythmias. In this study, we determined whether similar salutary effects are achieved with acute treatment with troglitazone. Anesthetized pigs underwent 90 min of regional LV ischemia and 90 min of reperfusion. Fifteen pigs were treated with troglitazone (10 mg/kg load, 5 mg. kg(-1). h(-1) infusion i.v.) beginning 1 h before ischemia. Seven pigs received corresponding vehicle. Plasma troglitazone concentration (mean 5 microg/ml) was similar to that achieved in clinical use of this agent. Before ischemia, acute troglitazone treatment had no effect on LV function, electrocardiogram, or substrate utilization. During ischemia or reperfusion, eight pigs in the troglitazone group died of ventricular fibrillation, compared with no pigs in the vehicle group (P < 0.05). Pigs that developed ventricular fibrillation had shorter QT intervals than survivors of either group. Among survivors, neither LV function nor substrate utilization differed between groups. Acute treatment with troglitazone increases susceptibility to ventricular fibrillation during myocardial ischemia and reperfusion. Whether thiazolidinediones have proarrhythmic potential in clinical use requires further investigation.
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Affiliation(s)
- Ya Xu
- VA Medical Center and University of Colorado Health Sciences Center, Denver, CO, USA
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