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Oh SB, Cho S, Kim HJ, Kim SJ. Differential expression of the enzymes regulating myosin light chain phosphorylation are responsible for the slower relaxation of pulmonary artery than mesenteric artery in rats. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2024; 28:49-57. [PMID: 38154964 PMCID: PMC10762492 DOI: 10.4196/kjpp.2024.28.1.49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/06/2023] [Accepted: 11/13/2023] [Indexed: 12/30/2023]
Abstract
While arterial tone is generally determined by the phosphorylation of Ser19 in myosin light chain (p-MLC2), Thr18/Ser19 diphosphorylation of MLC2 (pp-MLC2) has been suggested to hinder the relaxation of smooth muscle. In a dual-wire myography of rodent pulmonary artery (PA) and mesenteric artery (MA), we noticed significantly slower relaxation in PA than in MA after 80 mM KCl-induced condition (80K-contraction). Thus, we investigated the MLC2 phosphorylation and the expression levels of its regulatory enzymes; soluble guanylate cyclase (sGC), Rho-A dependent kinase (ROCK) and myosin light chain phosphatase target regulatory subunit (MYPT1). Immunoblotting showed higher sGC-α and ROCK2 in PA than MA, while sGC-β and MYPT1 levels were higher in MA than in PA. Interestingly, the level of pp-MLC2 was higher in PA than in MA without stimulation. In the 80K-contraction state, the levels of p-MLC2 and pp-MLC2 were commonly increased. Treatment with the ROCK inhibitor (Y27632, 10 μM) reversed the higher pp-MLC2 in PA. In the myography study, pharmacological inhibition of sGC (ODQ, 10 μM) slowed relaxation during washout, which was more pronounced in PA than in MA. The simultaneous treatment of Y27632 and ODQ reversed the impaired relaxation in PA and MA. Although treatment of PA with Y27632 alone could increase the rate of relaxation, it was still slower than that of MA without Y27632 treatment. Taken together, we suggest that the higher ROCK and lower MYPT in PA would have induced the higher level of MLC2 phosphorylation, which is responsible for the characteristic slow relaxation in PA.
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Affiliation(s)
- Seung Beom Oh
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Suhan Cho
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hyun Jong Kim
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Korea
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Korea
| | - Sung Joon Kim
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 03080, Korea
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Cho S, Oh SB, Kim HJ, Kim SJ. T18/S19 diphosphorylation of myosin regulatory light chain impairs pulmonary artery relaxation in monocrotaline-induced pulmonary hypertensive rats. Pflugers Arch 2023; 475:1097-1112. [PMID: 37422604 DOI: 10.1007/s00424-023-02836-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/29/2023] [Accepted: 06/26/2023] [Indexed: 07/10/2023]
Abstract
Phosphorylation of Ser19 (S19-p) on the myosin regulatory light chain (MLC2) is critical for arterial contraction. It has been shown that elevated RhoA-dependent kinase (ROCK) activity or decreased MLC phosphatase (MLCP) activity leads to further phosphorylation of Thr18 (T18/S19-pp), which has been linked to vasospastic diseases. However, this phenomenon has not yet been studied in the context of pulmonary arterial hypertension (PAH). In the monocrotaline-induced PAH (PAH-MCT) rat model, we observed a significant delay in pulmonary artery (PA) relaxation following high potassium-induced contraction, which persisted even with the use of an L-type calcium channel blocker or in a calcium-free solution. Immunoblot analysis showed increased levels of both S19-p and T18/S19-pp in unstimulated PAs from PAH-MCT rats. Proteomics analysis revealed a reduction in soluble guanylate cyclase (sGC) and protein kinase G (PKG) levels, and immunoblotting confirmed decreased levels of MYPT1 (a component of MLCP) and increased ROCK in PAH-MCT. In the control PAs, the pharmacological inhibition of sGC with ODQ resulted in a prominent delay of relaxation and increased T18/S19-pp as in PAH-MCT. The delayed relaxation and the T18/S19-pp in PAH-MCT were reversed by ROCK inhibitor, Y27632, while not by membrane permeable 8-Br-cGMP. The delayed relaxation and T18/S19-diP in the ODQ-treated control PA were also reversed by Y27632. Taken together, the decreased sGC and MLCP, and increased ROCK increased T18/S19-pp, which leads to the decreased ability of PA to relax in PAH-MCT rats. PA specific inhibition of ROCK or activation of MLCP are expected to serve as potential drugs in the treatment of PAH.
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Affiliation(s)
- Suhan Cho
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Seung Beom Oh
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, South Korea
| | - Hae Jin Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, South Korea
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, 03080, South Korea
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, MO, Columbia, USA
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, South Korea.
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, 03080, South Korea.
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Essential Role of Rho-Associated Kinase in ABO Immune Complex-Mediated Endothelial Barrier Disruption. Biomedicines 2021; 9:biomedicines9121851. [PMID: 34944667 PMCID: PMC8698390 DOI: 10.3390/biomedicines9121851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 11/17/2022] Open
Abstract
ABO immune complexes (ABO-IC) formed by ABO-incompatible antigen-antibody interaction are associated with hemolysis and platelet destruction in patients transfused with ABO-nonidentical blood products. However, the effects of ABO-IC on endothelial cells (EC) are unclear. ABO-IC were formed in vitro from normal donor-derived plasma and serum. Human pulmonary artery EC (HPAEC) were cultured and treated with media, ABO-identical and –non-identical plasma, and ABO-IC. EC barrier integrity was evaluated using transendothelial electrical resistance (TEER), scanning electron microscopy (SEM), vascular endothelial (VE)-cadherin and phalloidin staining, and Rho-associated Kinase (ROCK) inhibitor treatment. TEER revealed significant/irreversible barrier disruption within 1–2 h of exposure to ABO non-identical plasma and ABO-IC; this occurred independently of EC ABO type. Treatment with ABO-IC resulted in decreased VE-cadherin staining and increased phalloidin staining in a time-dependent manner, suggesting that the resultant increased EC barrier permeability is secondary to actin stress fiber formation and loss of cell surface VE-cadherin. Inhibition of ROCK was effective in protecting against IC-induced barrier disruption even two hours after ABO-IC exposure. ABO-IC causes increased EC barrier permeability by decreasing cell surface VE-cadherin and promoting stress fiber formation, which is preventable by inhibiting ROCK activation to protect against EC contraction and gap formation.
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Han YS, Delmotte P, Sieck GC. Effects of TNFα on Dynamic Cytosolic Ca 2 + and Force Responses to Muscarinic Stimulation in Airway Smooth Muscle. Front Physiol 2021; 12:730333. [PMID: 34393833 PMCID: PMC8363307 DOI: 10.3389/fphys.2021.730333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/09/2021] [Indexed: 11/30/2022] Open
Abstract
Previously, we reported that in airway smooth muscle (ASM), the cytosolic Ca2+ ([Ca2+]cyt) and force response induced by acetyl choline (ACh) are increased by exposure to the pro-inflammatory cytokine tumor necrosis factor α (TNFα). The increase in ASM force induced by TNFα was not associated with an increase in regulatory myosin light chain (rMLC20) phosphorylation but was associated with an increase in contractile protein (actin and myosin) concentration and an enhancement of Ca2+ dependent actin polymerization. The sensitivity of ASM force generation to elevated [Ca2+]cyt (Ca2+ sensitivity) is dynamic involving both the shorter-term canonical calmodulin-myosin light chain kinase (MLCK) signaling cascade that regulates rMLC20 phosphorylation and cross-bridge recruitment as well as the longer-term regulation of actin polymerization that regulates contractile unit recruitment and actin tethering to the cortical cytoskeleton. In this study, we simultaneously measured [Ca2+]cyt and force responses to ACh and explored the impact of 24-h TNFα on the dynamic relationship between [Ca2+]cyt and force responses. The temporal delay between the onset of [Ca2+]cyt and force responses was not affected by TNFα. Similarly, the rates of rise of [Ca2+]cyt and force responses were not affected by TNFα. The absence of an impact of TNFα on the short delay relationships between [Ca2+]cyt and force was consistent with the absence of an effect of [Ca2+]cyt and force on rMLC20 phosphorylation. However, the integral of the phase-loop plot of [Ca2+]cyt and force increased with TNFα, consistent with an impact on actin polymerization and, contractile unit recruitment and actin tethering to the cortical cytoskeleton.
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Affiliation(s)
- Young-Soo Han
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Philippe Delmotte
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
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Han YS, Delmotte PF, Arteaga GM, Sieck GC. Dynamic cytosolic Ca 2+ and force responses to muscarinic stimulation in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2021; 321:L91-L101. [PMID: 33908264 DOI: 10.1152/ajplung.00596.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
During agonist stimulation of airway smooth muscle (ASM), agonists such as ACh induce a transient increase in cytosolic Ca2+ concentration ([Ca2+]cyt), which leads to a contractile response [excitation-contraction (E-C) coupling]. Previously, the sensitivity of the contractile response of ASM to elevated [Ca2+]cyt (Ca2+ sensitivity) was assessed as the ratio of maximum force to maximum [Ca2+]cyt. However, this static assessment of Ca2+ sensitivity overlooks the dynamic nature of E-C coupling in ASM. In this study, we simultaneously measured [Ca2+]cyt and isometric force responses to three concentrations of ACh (1, 2.6, and 10 μM). Both maximum [Ca2+]cyt and maximum force responses were ACh concentration dependent, but force increased disproportionately, thereby increasing static Ca2+ sensitivity. The dynamic properties of E-C coupling were assessed in several ways. The temporal delay between the onset of ACh-induced [Ca2+]cyt and onset force responses was not affected by ACh concentration. The rates of rise of the ACh-induced [Ca2+]cyt and force responses increased with increasing ACh concentration. The integral of the phase-loop plot of [Ca2+]cyt and force from onset to steady state also increased with increasing ACh concentration, whereas the rate of relaxation remained unchanged. Although these results suggest an ACh concentration-dependent increase in the rate of cross-bridge recruitment and in the rate of rise of [Ca2+]cyt, the extent of regulatory myosin light-chain (rMLC20) phosphorylation was not dependent on ACh concentration. We conclude that the dynamic properties of [Ca2+]cyt and force responses in ASM are dependent on ACh concentration but reflect more than changes in the extent of rMLC20 phosphorylation.
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Affiliation(s)
- Young-Soo Han
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Philippe F Delmotte
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Grace M Arteaga
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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Yang Q, Fujii W, Kaji N, Kakuta S, Kada K, Kuwahara M, Tsubone H, Ozaki H, Hori M. The essential role of phospho‐T38 CPI‐17 in the maintenance of physiological blood pressure using genetically modified mice. FASEB J 2018; 32:2095-2109. [DOI: 10.1096/fj.201700794r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- Qunhui Yang
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Wataru Fujii
- Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Noriyuki Kaji
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Shigeru Kakuta
- Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Kodai Kada
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Masayoshi Kuwahara
- Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Hirokazu Tsubone
- Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Hiroshi Ozaki
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
| | - Masatoshi Hori
- Department of Veterinary Pharmacology, Laboratory of Applied Genetics, Department of Biomedical Science, Department of Veterinary Pathophysiology and Animal Health, and Research Center for Food SafetyGraduate School of Agriculture and Life Sciences, The University of TokyoTokyoJapan
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Satoh T, Kurita M, Suga H, Eto H, Ozaki M, Takushima A, Harii K. Efficient isolation and culture of endothelial cells from venous malformation using the Rho-associated protein kinase inhibitor Y27632. J Plast Surg Hand Surg 2017; 52:60-66. [PMID: 28554252 DOI: 10.1080/2000656x.2017.1330754] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND The investigation of primary cells from a pathological lesion can elucidate the pathogenesis of diseases, but, for vascular malformations in humans, such basic research is still stagnant, because the isolation and culture of vascular endothelial cells (ECs) is very difficult. To obtain a sufficient amount of ECs from venous malformation (VM) this study took advantage of a Rho-associated protein kinase inhibitor, Y27632, which had been used for the efficient procurement of primary keratinocytes. METHODS ECs were isolated and cultured from VM lesions, combining enzymatic digestion, cell sorting, and Y27632. The proliferative effect of Y27632 on ECs was examined by proliferation assay. The characteristics of the ECs cultured with Y27632 by EC marker expression and tube formation assay were also examined. RESULTS Y27632 enhanced the proliferation of ECs and elongated the senescence of the cells. The expression of specific markers of ECs such as von Willebrand factor, endothelin-1, and VE-cadherin, was confirmed in the cells cultured with Y27632. In a tube formation assay, the cells cultured with Y27632 showed higher tube formation ability compared to the cells cultured without Y27632, indicating that Y27632 promoted the angiogenic capability of ECs. CONCLUSIONS The protocol using Y27632 offers a new EC culture methodology and provides a new option for the biological investigation of vascular malformations. This new method will contribute to other types of vascular biology research as well.
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Affiliation(s)
- Takashi Satoh
- a Department of Plastic Surgery , Kyorin University School of Medicine , Tokyo , Japan
| | - Masakazu Kurita
- a Department of Plastic Surgery , Kyorin University School of Medicine , Tokyo , Japan
| | - Hirotaka Suga
- a Department of Plastic Surgery , Kyorin University School of Medicine , Tokyo , Japan
| | - Hitomi Eto
- a Department of Plastic Surgery , Kyorin University School of Medicine , Tokyo , Japan
| | - Mine Ozaki
- a Department of Plastic Surgery , Kyorin University School of Medicine , Tokyo , Japan
| | - Akihiko Takushima
- a Department of Plastic Surgery , Kyorin University School of Medicine , Tokyo , Japan
| | - Kiyonori Harii
- a Department of Plastic Surgery , Kyorin University School of Medicine , Tokyo , Japan
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Ferland DJ, Darios ES, Neubig RR, Sjögren B, Truong N, Torres R, Dexheimer TS, Thompson JM, Watts SW. Chemerin-induced arterial contraction is G i- and calcium-dependent. Vascul Pharmacol 2016; 88:30-41. [PMID: 27890480 DOI: 10.1016/j.vph.2016.11.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/27/2016] [Accepted: 11/21/2016] [Indexed: 12/12/2022]
Abstract
Chemerin is an adipokine associated with increased blood pressure, and may link obesity with hypertension. We tested the hypothesis that chemerin-induced contraction of the vasculature occurs via calcium flux in smooth muscle cells. Isometric contraction of rat aortic rings was performed in parallel with calcium kinetics of rat aortic smooth muscle cells to assess the possible signaling pathway. Chemerin-9 (nonapeptide of the chemerin S157 isoform) caused a concentration-dependent contraction of isolated aorta (EC50 100nM) and elicited a concentration-dependent intracellular calcium response (EC50 10nM). Pertussis toxin (Gi inhibitor), verapamil (L-type Ca2+ channel inhibitor), PP1 (Src inhibitor), and Y27632 (Rho kinase inhibitor) reduced both calcium influx and isometric contraction to chemerin-9 but PD098059 (Erk MAPK inhibitor) and U73122 (PLC inhibitor) had little to no effect on either measure of chemerin signaling. Although our primary aim was to examine chemerin signaling, we also highlight differences in the mechanisms of chemerin-9 and recombinant chemerin S157. These data support a chemerin-induced contractile mechanism in vascular smooth muscle that functions through Gi proteins to activate L-type Ca2+ channels, Src, and Rho kinase. There is mounting evidence linking chemerin to hypertension and this mechanism brings us closer to targeting chemerin as a form of therapy.
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MESH Headings
- Animals
- Aorta/drug effects
- Aorta/metabolism
- Calcium/metabolism
- Calcium Channels, L-Type/metabolism
- Chemokines/administration & dosage
- Chemokines/metabolism
- Dose-Response Relationship, Drug
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Hypertension/physiopathology
- Intercellular Signaling Peptides and Proteins/administration & dosage
- Intercellular Signaling Peptides and Proteins/metabolism
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Rats
- Rats, Sprague-Dawley
- Signal Transduction/drug effects
- rho-Associated Kinases/metabolism
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Affiliation(s)
- David J Ferland
- Department of Pharmacology and Toxicology, 1355 Bogue Street Rm B445, Michigan State University, East Lansing, MI 48824-1317, United States.
| | - Emma S Darios
- Department of Pharmacology and Toxicology, 1355 Bogue Street Rm B445, Michigan State University, East Lansing, MI 48824-1317, United States
| | - Richard R Neubig
- Department of Pharmacology and Toxicology, 1355 Bogue Street Rm B445, Michigan State University, East Lansing, MI 48824-1317, United States
| | - Benita Sjögren
- Department of Pharmacology and Toxicology, 1355 Bogue Street Rm B445, Michigan State University, East Lansing, MI 48824-1317, United States
| | - Nguyen Truong
- Department of Pharmacology and Toxicology, 1355 Bogue Street Rm B445, Michigan State University, East Lansing, MI 48824-1317, United States
| | - Rosa Torres
- Department of Pharmacology and Toxicology, 1355 Bogue Street Rm B445, Michigan State University, East Lansing, MI 48824-1317, United States
| | - Thomas S Dexheimer
- Department of Pharmacology and Toxicology, 1355 Bogue Street Rm B445, Michigan State University, East Lansing, MI 48824-1317, United States
| | - Janice M Thompson
- Department of Pharmacology and Toxicology, 1355 Bogue Street Rm B445, Michigan State University, East Lansing, MI 48824-1317, United States
| | - Stephanie W Watts
- Department of Pharmacology and Toxicology, 1355 Bogue Street Rm B445, Michigan State University, East Lansing, MI 48824-1317, United States
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Nour-Eldine W, Ghantous CM, Zibara K, Dib L, Issaa H, Itani HA, El-Zein N, Zeidan A. Adiponectin Attenuates Angiotensin II-Induced Vascular Smooth Muscle Cell Remodeling through Nitric Oxide and the RhoA/ROCK Pathway. Front Pharmacol 2016; 7:86. [PMID: 27092079 PMCID: PMC4823273 DOI: 10.3389/fphar.2016.00086] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/16/2016] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Adiponectin (APN), an adipocytokine, exerts protective effects on cardiac remodeling, while angiotensin II (Ang II) induces hypertension and vascular remodeling. The potential protective role of APN on the vasculature during hypertension has not been fully elucidated yet. Here, we evaluate the molecular mechanisms of the protective role of APN in the physiological response of the vascular wall to Ang II. METHODS AND RESULTS Rat aortic tissues were used to investigate the effect of APN on Ang II-induced vascular remodeling and hypertrophy. We investigated whether nitric oxide (NO), the RhoA/ROCK pathway, actin cytoskeleton remodeling, and reactive oxygen species (ROS) mediate the anti-hypertrophic effect of APN. Ang II-induced protein synthesis was attenuated by pre-treatment with APN, NO donor S-nitroso-N-acetylpenicillamine (SNAP), or cGMP. The hypertrophic response to Ang II was associated with a significant increase in RhoA activation and vascular force production, which were prevented by APN and SNAP. NO was also associated with inhibition of Ang II-induced phosphorylation of cofilin. In addition, immunohistochemistry revealed that 24 h Ang II treatment increased the F- to G-actin ratio, an effect that was inhibited by SNAP. Ang II-induced ROS formation and upregulation of p22(phox) mRNA expression were inhibited by APN and NO. Both compounds failed to inhibit Nox1 and p47(phox) expression. CONCLUSION Our results suggest that the anti-hypertrophic effects of APN are due, in part, to NO-dependent inhibition of the RhoA/ROCK pathway and ROS formation.
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Affiliation(s)
- Wared Nour-Eldine
- Cardiovascular Physiology Lab, Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of BeirutBeirut, Lebanon; ER045, Laboratory of Stem Cells, Department of Biology, Faculty of Sciences, The Lebanese UniversityBeirut, Lebanon
| | - Crystal M Ghantous
- Cardiovascular Physiology Lab, Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut Beirut, Lebanon
| | - Kazem Zibara
- ER045, Laboratory of Stem Cells, Department of Biology, Faculty of Sciences, The Lebanese University Beirut, Lebanon
| | - Leila Dib
- Cardiovascular Physiology Lab, Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut Beirut, Lebanon
| | - Hawraa Issaa
- Cardiovascular Physiology Lab, Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of BeirutBeirut, Lebanon; ER045, Laboratory of Stem Cells, Department of Biology, Faculty of Sciences, The Lebanese UniversityBeirut, Lebanon
| | - Hana A Itani
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville TN, USA
| | - Nabil El-Zein
- ER045, Laboratory of Stem Cells, Department of Biology, Faculty of Sciences, The Lebanese University Beirut, Lebanon
| | - Asad Zeidan
- Cardiovascular Physiology Lab, Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut Beirut, Lebanon
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Kumcu EK, Aydinoglu F, Astarci E, Ogulener N. The effect of sub-chronic systemic ethanol treatment on corpus cavernosal smooth muscle contraction: the contribution of RhoA/Rho-kinase. Naunyn Schmiedebergs Arch Pharmacol 2016; 389:249-58. [DOI: 10.1007/s00210-015-1204-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 12/21/2015] [Indexed: 12/21/2022]
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Alotaibi M. The effect of cinnamon extract on isolated rat uterine strips. Reprod Biol 2015; 16:27-33. [PMID: 26952750 DOI: 10.1016/j.repbio.2015.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/24/2015] [Accepted: 12/05/2015] [Indexed: 11/13/2022]
Abstract
Cinnamon is a spice used by some populations as a traditional remedy to control blood pressure and thus hypertension. Cinnamon extract decreases contractility in some smooth muscles, but its effect on uterine smooth muscle is unknown. The aim of this study was to determine the physiological and pharmacological effects of cinnamon extract (CE) on the contractions of isolated rat uterine strips and to investigate its possible mechanism of action. Isolated longitudinal uterine strips were dissected from non-pregnant rats, mounted vertically in an organ bath chamber, and exposed to different concentrations of CE (10-20mg/mL). The effect of CE was investigated in the presence of each of the following solutions: 60mM KCl, 5nM oxytocin, and 1μM Bay K8644. CE significantly decreased the force of uterine contraction in a concentration-dependent manner and significantly attenuated the uterine contractions elicited by KCl and oxytocin. In addition, CE significantly decreased the contractile force elicited when L-type Ca(2+) channels were activated by Bay K8644. CE's major mechanism may be inhibition of L-type Ca(2+) channels, which limits calcium influx. These data demonstrate that CE can be a potent tocolytic that can decrease uterine activity regardless of how the force was produced, even when the uterus was stimulated by agonists. As a result, cinnamon may be used to alleviate menstrual pain associated with dysmenorrhoea or prevent unwanted uterine activity in early pregnancy.
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Affiliation(s)
- Mohammed Alotaibi
- Department of Physiology, College of Medicine, King Saud University and King Khalid University Hospital, P.O Box 2925, Riyadh 11461, Saudi Arabia.
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12
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MacDonald JA, Sutherland C, Carlson DA, Bhaidani S, Al-Ghabkari A, Swärd K, Haystead TAJ, Walsh MP. A Small Molecule Pyrazolo[3,4-d]Pyrimidinone Inhibitor of Zipper-Interacting Protein Kinase Suppresses Calcium Sensitization of Vascular Smooth Muscle. Mol Pharmacol 2015; 89:105-17. [DOI: 10.1124/mol.115.100529] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/09/2015] [Indexed: 11/22/2022] Open
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Anderson CD, Kendig DM, Al-Qudah M, Mahavadi S, Murthy KS, Grider JR. Role of various kinases in muscarinic M3 receptor-mediated contraction of longitudinal muscle of rat colon. J Smooth Muscle Res 2015; 50:103-19. [PMID: 25891767 PMCID: PMC4862207 DOI: 10.1540/jsmr.50.103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The longitudinal muscle layer in gut is the functional opponent to the circular muscle
layer during peristalsis. Differences in innervation of the layers allow for the
contraction of one layer concurrently with the relaxation of the other, enabling the
passage of gut contents in a controlled fashion. Differences in development have given the
cells of the two layers differences in receptor populations, membrane lipid handling, and
calcium handling profiles/behaviors. The contractile activity of the longitudinal muscle
is largely mediated by cholinergic neural input from myenteric plexus. Activation of
muscarinic receptors leads to rapid activation of several kinases including MLC kinase,
ERK1/2, CaMKII and Rho kinase. Phosphorylation of myosin light chain (MLC20) by
MLC kinase (MLCK) is a prerequisite for contraction in both circular and longitudinal
muscle cells. In rat colonic longitudinal muscle strips, we measured muscarinic
receptor-mediated contraction following incubation with kinase inhibitors. Basal tension
was differentially regulated by Rho kinase, ERK1/2, CaMKII and CaMKK. Selective inhibitors
of Rho kinase, ERK1/2, CaMKK/AMPK, and CaMKII each reduced carbachol-induced contraction
in the innervated muscle strips. These inhibitors had no direct effect on MLCK activity.
Thus unlike previously reported for isolated muscle cells where CaMKII and ERK1/2 are not
involved in contraction, we conclude that the regulation of carbachol-induced contraction
in innervated longitudinal muscle strips involves the interplay of Rho kinase, ERK1/2,
CaMKK/AMPK, and CAMKII.
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Affiliation(s)
- Charles D Anderson
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, USA
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Aalbaek F, Bonde L, Kim S, Boedtkjer E. Perivascular tissue inhibits rho-kinase-dependent smooth muscle Ca(2+) sensitivity and endothelium-dependent H2 S signalling in rat coronary arteries. J Physiol 2015; 593:4747-64. [PMID: 26350036 DOI: 10.1113/jp271006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/24/2015] [Indexed: 11/08/2022] Open
Abstract
Interactions between perivascular tissue (PVT) and the vascular wall modify artery tone and contribute to local blood flow regulation. Using isometric myography, fluorescence microscopy, membrane potential recordings and phosphospecific immunoblotting, we investigated the cellular mechanisms by which PVT affects constriction and relaxation of rat coronary septal arteries. PVT inhibited vasoconstriction to thromboxane, serotonin and α1 -adrenergic stimulation but not to depolarization with elevated extracellular [K(+) ]. When PVT was wrapped around isolated arteries or placed at the bottom of the myograph chamber, a smaller yet significant inhibition of vasoconstriction was observed. Resting membrane potential, depolarization to serotonin or thromboxane stimulation, and resting and serotonin-stimulated vascular smooth muscle [Ca(2+) ]-levels were unaffected by PVT. Serotonin-induced vasoconstriction was almost abolished by rho-kinase inhibitor Y-27632 and modestly reduced by protein kinase C inhibitor bisindolylmaleimide X. PVT reduced phosphorylation of myosin phosphatase targeting subunit (MYPT) at Thr850 by ∼40% in serotonin-stimulated arteries but had no effect on MYPT-phosphorylation in arteries depolarized with elevated extracellular [K(+) ]. The net anti-contractile effect of PVT was accentuated after endothelial denudation. PVT also impaired vasorelaxation and endothelial Ca(2+) responses to cholinergic stimulation. Methacholine-induced vasorelaxation was mediated by NO and H2 S, and particularly the H2 S-dependent (dl-propargylglycine- and XE991-sensitive) component was attenuated by PVT. Vasorelaxation to NO- and H2 S-donors was maintained in arteries with PVT. In conclusion, cardiomyocyte-rich PVT surrounding coronary arteries releases diffusible factors that reduce rho-kinase-dependent smooth muscle Ca(2+) sensitivity and endothelial Ca(2+) responses. These mechanisms inhibit agonist-induced vasoconstriction and endothelium-dependent vasorelaxation and suggest new signalling pathways for metabolic regulation of blood flow.
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Affiliation(s)
- Filip Aalbaek
- Department of Biomedicine, Aarhus University, Denmark
| | - Lisbeth Bonde
- Department of Biomedicine, Aarhus University, Denmark
| | - Sukhan Kim
- Department of Biomedicine, Aarhus University, Denmark
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Aydinoglu F, Ergurhan Kiroglu O, Astarci E, Balli E, Ogulener N. Effects of ethanol on RhoA/Rho-kinase-mediated calcium sensitization in mouse lung parenchymal tissue. Eur J Pharmacol 2015; 764:318-327. [PMID: 26169563 DOI: 10.1016/j.ejphar.2015.07.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/29/2015] [Accepted: 07/08/2015] [Indexed: 11/16/2022]
Abstract
Calcium sensitization by the RhoA/Rho-kinase (ROCK) pathway contributes to the contraction in smooth muscle. Contractile stimuli can sensitize myosin to Ca(2+) by activating RhoA/Rho-kinase that inhibits myosin light chain phosphatase activity. The present study was aimed at investigating the possible involvement of RhoA/Rho-kinase pathway in contractile responses to agonist (phenylephrine) and depolarizing (KCl) of mouse lung parenchymal tissues. Also, we investigated the effect of ethanol on RhoA/Rho-kinase pathway. Phenylephrine (10(-8)-10(-4) M) and KCl (10-80 mM) induced sustained contractions in parenchymal strips. Ethanol significantly attenuated the contractions to phenylephrine and KCl. The Rho-kinase inhibitors fasudil (5×10(-5) M) and Y-27632 (5×10(-5) M) inhibited contractions to in both control and ethanol-treated parenchymal strips. In addition, the relaxations induced by fasudil (10(-4) M) and Y-27632 (5×10(-4) M) on parenchymal strips contracted by phenylephrine but not KCl was decreased in ethanol-treatment group. Also, RhoA, ROCK1 and ROCK2 expressions were detected in mouse lung parenchymal tissue. In ethanol-treated group, expression of RhoA and ROCK1 but not ROCK2 decreased compared to control. Furthermore, ethanol causes apoptotic changes in alveolar type I epithelial cells of parenchymal tissue. These results suggest that RhoA/Rho-kinase signaling pathway plays an important role in phenylephrine- and KCl-induced Ca(2)(+) sensitization in mouse lung parenchymal tissue. Also, ethanol may be decrease phenylephrine- and KCl-induced contraction due to lowering the RhoA/Rho-kinase-mediated Ca(2+)-sensitizing by inhibiting RhoA/Rho-kinase pathway in parenchymal tissue. These results may be lead to important insights into the mechanisms of lung diseases due to alcohol consumption.
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Affiliation(s)
- Fatma Aydinoglu
- Department of Pharmacology, Pharmacy Faculty, Cukurova University, Adana, Turkey
| | | | - Erhan Astarci
- Department of Plant and Animal Production, Mudurnu Süreyya Astarci Vocational School, Abant Izzet Baysal University, Bolu, Turkey
| | - Ebru Balli
- Department of Histology and Embryology, Medical Faculty, Mersin University, Mersin, Turkey
| | - Nuran Ogulener
- Department of Pharmacology, Medical Faculty, Cukurova University, Adana, Turkey.
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Mills RD, Mita M, Walsh MP. A role for the Ca2+-dependent tyrosine kinase Pyk2 in tonic depolarization-induced vascular smooth muscle contraction. J Muscle Res Cell Motil 2015; 36:479-89. [DOI: 10.1007/s10974-015-9416-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 06/27/2015] [Indexed: 10/24/2022]
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17
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Xie YL, Zhou M, Ma HH, Wang X, Liu JJ. Vasorelaxation effect of gastrodin on isolated thoracic aorta rings of rats. Chin J Integr Med 2015; 21:944-8. [DOI: 10.1007/s11655-015-2082-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Indexed: 11/28/2022]
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18
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Kupittayanant S, Munglue P, Lijuan W, Promprom W, Budhaklala N, Wray S. Finding new agents in medicinal plants to act on the myometrium. Exp Physiol 2014; 99:530-7. [DOI: 10.1113/expphysiol.2013.072884] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Sajeera Kupittayanant
- Institute of Science; Suranaree University of Technology; Muang District Nakhon Ratchasima Thailand
| | - Phukphon Munglue
- Faculty of Science; Ubon Ratchathani Rajabhat University; Muang District Ubon Ratchathani Thailand
| | - Wanwisa Lijuan
- Faculty of Science and Technology; Thepsatri Rajabhat University; Muang Lop Buri Lobburi Thailand
| | - Wilawan Promprom
- Faculty of Science; Mahasarakham University; Kantrawichai Mahasarakham Thailand
| | - Nopparat Budhaklala
- Faculty of Science; Rajamangala University of Technology Thanyaburi; Thanyaburi Pathum Thani Thailand
| | - Susan Wray
- Department of Cellular and Molecular Physiology; Institute of Translational Medicine; University of Liverpool; Liverpool UK
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Mita M, Tanaka H, Yanagihara H, Nakagawa JI, Hishinuma S, Sutherland C, Walsh MP, Shoji M. Membrane depolarization-induced RhoA/Rho-associated kinase activation and sustained contraction of rat caudal arterial smooth muscle involves genistein-sensitive tyrosine phosphorylation. J Smooth Muscle Res 2013; 49:26-45. [PMID: 24133693 PMCID: PMC5137315 DOI: 10.1540/jsmr.49.26] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Rho-associated kinase (ROK) activation plays an important role in K+-induced
contraction of rat caudal arterial smooth muscle (Mita et al., Biochem J. 2002; 364:
431–40). The present study investigated a potential role for tyrosine kinase activity in
K+-induced RhoA activation and contraction. The non-selective tyrosine kinase
inhibitor genistein, but not the src family tyrosine kinase inhibitor PP2, inhibited
K+-induced sustained contraction (IC50 = 11.3 ± 2.4 µM). Genistein
(10 µM) inhibited the K+-induced increase in myosin light chain
(LC20) phosphorylation without affecting the Ca2+ transient. The
tyrosine phosphatase inhibitor vanadate induced contraction that was reversed by genistein
(IC50 = 6.5 ± 2.3 µM) and the ROK inhibitor Y-27632 (IC50 = 0.27 ±
0.04 µM). Vanadate also increased LC20 phosphorylation in a genistein- and
Y-27632-dependent manner. K+ stimulation induced translocation of RhoA to the
membrane, which was inhibited by genistein. Phosphorylation of MYPT1 (myosin-targeting
subunit of myosin light chain phosphatase) was significantly increased at Thr855 and
Thr697 by K+ stimulation in a genistein- and Y-27632-sensitive manner. Finally,
K+ stimulation induced genistein-sensitive tyrosine phosphorylation of
proteins of ∼55, 70 and 113 kDa. We conclude that a genistein-sensitive tyrosine kinase,
activated by the membrane depolarization-induced increase in
[Ca2+]i, is involved in the RhoA/ROK activation and sustained
contraction induced by K+. Ca2+ sensitization, myosin light chain
phosphatase, RhoA, Rho-associated kinase, tyrosine kinase
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Affiliation(s)
- Mitsuo Mita
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Hitoshi Tanaka
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Hayato Yanagihara
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Jun-ichi Nakagawa
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Shigeru Hishinuma
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Cindy Sutherland
- Smooth Muscle Research Group, Department of Biochemistry and
Molecular Biology, University of Calgary, Canada
| | - Michael P. Walsh
- Smooth Muscle Research Group, Department of Biochemistry and
Molecular Biology, University of Calgary, Canada
| | - Masaru Shoji
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
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20
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Wan E, Kushner JS, Zakharov S, Nui XW, Chudasama N, Kelly C, Waase M, Doshi D, Liu G, Iwata S, Shiomi T, Katchman A, D'Armiento J, Homma S, Marx SO. Reduced vascular smooth muscle BK channel current underlies heart failure-induced vasoconstriction in mice. FASEB J 2013; 27:1859-67. [PMID: 23325318 DOI: 10.1096/fj.12-223511] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Excessively increased peripheral vasoconstriction is a hallmark of heart failure (HF). Here, we show that in mice with systolic HF post-myocardial infarction, the myogenic tone of third-order mesenteric resistance vessels is increased, the vascular smooth muscle (VSM) membrane potential is depolarized by ~20 mV, and vessel wall intracellular [Ca(2+)] is elevated relative to that in sham-operated control mice. Despite the increased [Ca(2+)], the frequency and amplitude of spontaneous transient outward currents (STOCs), mediated by large conductance, Ca(2+)-activated BK channels, were reduced by nearly 80% (P<0.01) and 25% (P<0.05), respectively, in HF. The expression of the BK α and β1 subunits was reduced in HF mice compared to controls (65 and 82% lower, respectively, P<0.01). Consistent with the importance of a reduction in BK channel expression and function in mediating the HF-induced increase in myogenic tone are two further findings: a blunting of paxilline-induced increase in myogenic tone in HF mice compared to controls (0.9 vs. 10.9%, respectively), and that HF does not alter the increased myogenic tone of BK β1-null mice. These findings identify electrical dysregulation within VSM, specifically the reduction of BK currents, as a key molecular mechanism sensitizing resistance vessels to pressure-induced vasoconstriction in systolic HF.
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Affiliation(s)
- Elaine Wan
- Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
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21
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Tazzeo T, Bates G, Roman HN, Lauzon AM, Khasnis MD, Eto M, Janssen LJ. Caffeine relaxes smooth muscle through actin depolymerization. Am J Physiol Lung Cell Mol Physiol 2012; 303:L334-42. [PMID: 22683573 DOI: 10.1152/ajplung.00103.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Caffeine is sometimes used in cell physiological studies to release internally stored Ca(2+). We obtained evidence that caffeine may also act through a different mechanism that has not been previously described and sought to examine this in greater detail. We ruled out a role for phosphodiesterase (PDE) inhibition, since the effect was 1) not reversed by inhibiting PKA or adenylate cyclase; 2) not exacerbated by inhibiting PDE4; and 3) not mimicked by submillimolar caffeine nor theophylline, both of which are sufficient to inhibit PDE. Although caffeine is an agonist of bitter taste receptors, which in turn mediate bronchodilation, its relaxant effect was not mimicked by quinine. After permeabilizing the membrane using β-escin and depleting the internal Ca(2+) store using A23187, we found that 10 mM caffeine reversed tone evoked by direct application of Ca(2+), suggesting it functionally antagonizes the contractile apparatus. Using a variety of molecular techniques, we found that caffeine did not affect phosphorylation of myosin light chain (MLC) by MLC kinase, actin-filament motility catalyzed by MLC kinase, phosphorylation of CPI-17 by either protein kinase C or RhoA kinase, nor the activity of MLC-phosphatase. However, we did obtain evidence that caffeine decreased actin filament binding to phosphorylated myosin heads and increased the ratio of globular to filamentous actin in precontracted tissues. We conclude that, in addition to its other non-RyR targets, caffeine also interferes with actin function (decreased binding by myosin, possibly with depolymerization), an effect that should be borne in mind in studies using caffeine to probe excitation-contraction coupling in smooth muscle.
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Affiliation(s)
- Tracy Tazzeo
- Firestone Institute for Respiratory Health, St. Joseph’s Hospital and the Department of Medicine, McMaster University, Hamilton, Ontario, Canada
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22
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Mori D, Hori M, Murata T, Ohama T, Kishi H, Kobayashi S, Ozaki H. Synchronous phosphorylation of CPI-17 and MYPT1 is essential for inducing Ca(2+) sensitization in intestinal smooth muscle. Neurogastroenterol Motil 2011; 23:1111-22. [PMID: 22004286 DOI: 10.1111/j.1365-2982.2011.01799.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Myosin phosphatase activity is regulated by mechanisms involving the phosphorylation of CPI-17 and MYPT1, primarily based on studies with tonic-type vascular smooth muscles. This study examined how these mechanisms contribute to the regulation of contraction of a phasic-type intestinal smooth muscle. METHODS Phosphorylation levels, tension, and Ca(2+) sensitization was detected in rat ileal smooth muscle. Key Results In rat ileal smooth muscle, phosphorylation level of CPI-17 at Thr(38) and MYPT1 at Thr(853) , but not MYPT1 at Thr(696) , were increased with carbachol (1μmolL(-1) ) accompanied with muscle contraction. The PKC inhibitor Go6976 (1μmol L(-1) ) inhibited the carbachol-induced phosphorylation of CPI-17, whereas the Rho-associated kinase (ROCK) inhibitor, Y-27632 (10μmol L(-1) ) inhibited the carbachol-induced phosphorylation of both CPI-17 and MYPT1. Application of Go6976 or Y-27632 alone inhibited the carbachol-induced contraction; however, the combined application of these inhibitors did not inhibit the contraction in an additive manner. In β-escin-permeabilized ileal strip, treatment with antiphosphorylated antibodies for CPI-17 at Thr(38) and MYPT1 at Thr(853) and Thr(696) alone almost completely abolished the Ca(2+) sensitization due to carbachol with GTP. CONCLUSIONS & INFERENCES In conclusion, receptor stimulation increases the Ca(2+) sensitivity of contractile elements through CPI-17 phosphorylation via the PKC/ROCK pathways and MYPT1 phosphorylation via the ROCK pathway, when these mechanisms operate cooperatively and/or synchronously in intestinal smooth muscle.
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Affiliation(s)
- D Mori
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, the University of Tokyo, Tokyo, Japan
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Borysova L, Shabir S, Walsh MP, Burdyga T. The importance of Rho-associated kinase-induced Ca2+ sensitization as a component of electromechanical and pharmacomechanical coupling in rat ureteric smooth muscle. Cell Calcium 2011; 50:393-405. [PMID: 21839512 DOI: 10.1016/j.ceca.2011.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 07/05/2011] [Accepted: 07/07/2011] [Indexed: 01/30/2023]
Abstract
Ureteric peristalsis, which occurs via alternating contraction and relaxation of ureteric smooth muscle, ensures the unidirectional flow of urine from the kidney to the bladder. Understanding of the molecular mechanisms underlying ureteric excitation-contraction coupling, however, is limited. To address these knowledge deficits, and in particular to test the hypothesis that Ca2+ sensitization via activation of the RhoA/Rho-associated kinase (ROK) pathway plays an important role in ureteric smooth muscle contraction, we carried out a thorough characterization of the electrical activity, Ca2+ signaling, MYPT1 (myosin targeting subunit of myosin light chain phosphatase, MLCP) and myosin regulatory light chain (LC20) phosphorylation, and force responses to membrane depolarization induced by KCl (electromechanical coupling) and carbachol (CCh) (pharmacomechanical coupling). The effects of ROK inhibition on these parameters were investigated. We conclude that the tonic, but not the phasic component of KCl- or CCh-induced ureteric smooth muscle contraction is highly dependent on ROK-catalyzed phosphorylation of MYPT1 at T855, leading to inhibition of MLCP and increased LC20 phosphorylation.
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Affiliation(s)
- Lyudmyla Borysova
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool L69 3BX, UK
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Rho-kinase inhibition attenuates calcium-induced contraction in β-escin but not Triton X-100 permeabilized rabbit femoral artery. J Muscle Res Cell Motil 2011; 32:77-88. [PMID: 21706258 DOI: 10.1007/s10974-011-9253-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 05/31/2011] [Indexed: 01/09/2023]
Abstract
K+-depolarization (KCl) of smooth muscle has long been known to cause Ca2+-dependent contraction, but only recently has this G protein-coupled receptor (GPCR)-independent stimulus been associated with rhoA kinase (ROCK)-dependent myosin light chain (MLC) phosphatase inhibition and Ca2+ sensitization. This study examined effects of ROCK inhibition on the concentration-response curves (CRCs) generated in femoral artery by incrementally adding increasing concentrations of KCl to intact tissues, and Ca2+ to tissues permeabilized with Triton X-100, β-escin and α-toxin. For a comparison, tissue responses were assessed also in the presence of protein kinase C (PKC) and MLC kinase inhibition. The ROCK inhibitor H-1152 induced a strong concentration-dependent inhibition of a KCl CRC. A relatively low GF-109203X concentration (1 μM) sufficient to inhibit conventional PKC isotypes also inhibited the KCl CRC but did not affect the maximum tension. ROCK inhibitors had no effect on the Ca2+ CRC induced in Triton X-100 or α-toxin permeabilized tissues, but depressed the maximum contraction induced in β-escin permeabilized tissue. GF-109203X at 1 μM depressed the maximum Ca2+-dependent contraction induced in α-toxin permeabilized tissue and had no effect on the Ca2+ CRC induced in Triton X-100 permeabilized tissue. The MLC kinase inhibitor wortmannin (1 μM) strongly depression the Ca2+ CRCs in tissues permeabilized with Triton X-100, α-toxin and β-escin. H-1152 inhibited contractions induced by a single exposure to a submaximum [Ca2+] (pCa 6) in both rabbit and mouse femoral arteries. These data indicate that β-escin permeabilized muscle preserves GPCR-independent, Ca2+- and ROCK-dependent, Ca2+ sensitization.
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Role of myosin light chain kinase and myosin light chain phosphatase in the resistance arterial myogenic response to intravascular pressure. Arch Biochem Biophys 2011; 510:160-73. [DOI: 10.1016/j.abb.2011.02.024] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/24/2011] [Accepted: 02/28/2011] [Indexed: 12/19/2022]
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Kajita M, Murata T, Horiguchi K, Iizuka M, Hori M, Ozaki H. iNOS expression in vascular resident macrophages contributes to circulatory dysfunction of splanchnic vascular smooth muscle contractions in portal hypertensive rats. Am J Physiol Heart Circ Physiol 2010; 300:H1021-31. [PMID: 21193589 DOI: 10.1152/ajpheart.00563.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Portal hypertension, a major complication of cirrhosis, is caused by both increased portal blood flow due to arterial vasodilation and augmented intrahepatic vascular resistance due to sinusoidal constriction. In this study, we examined the possible involvement of resident macrophages in the tone regulation of splanchnic blood vessels using bile duct ligated (BDL) portal hypertensive rats and an in vitro organ culture method. In BDL cirrhosis, the number of ED2-positive resident macrophages increased by two- to fourfold in the vascular walls of the mesenteric artery and extrahepatic portal vein compared with those in sham-operated rats. Many ED1-positive monocytes were also recruited into this area. The expression of inducible nitric oxide (NO) synthase (iNOS) mRNA was increased in the vascular tissues isolated from BDL rats, and accordingly, nitrate/nitrite production was increased. Immunohistochemistry revealed that iNOS was largely expressed in ED1-positive and ED2-positive cells. We further analyzed the effect of iNOS expression on vascular smooth muscle contraction using an in vitro organ culture system. iNOS mRNA expression and nitrate production significantly increased in vascular tissues (without endothelium) incubated with 1 μg/ml lipopolysaccharide (LPS) for 6 h. Immunohistochemistry indicated that iNOS was largely expressed in ED2-positive resident macrophages. α-Adrenergic-stimulated contractility of the mesenteric artery was greatly suppressed by LPS treatment and was restored by N(G)-nitro-L-arginine methyl ester (NO synthase inhibitor); in contrast, portal vein contractility was largely unaffected by LPS. Sodium nitroprusside (NO donor) and 8-bromo-cGMP showed greater contractile inhibition in the mesenteric artery than in the portal vein with decreasing myosin light chain phosphorylation. In the presence of an α-adrenergic agonist, the mesenteric artery cytosolic Ca(2+) level was greatly reduced by sodium nitroprusside; however, the portal vein Ca(2+) level was largely unaffected. These results suggest that the induction of iNOS in monocytes/macrophages contributes to a hypercirculatory state in the cirrhosis model rat in which the imbalance of the responsiveness of visceral vascular walls to NO (mesenteric artery >> portal vein) may account for the increased portal venous flow in portal hypertension.
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Affiliation(s)
- Masahiro Kajita
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
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27
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Alvarez SM, Miner AS, Browne BM, Ratz PH. Failure of Bay K 8644 to induce RhoA kinase-dependent calcium sensitization in rabbit blood vessels. Br J Pharmacol 2010; 160:1326-37. [PMID: 20590624 PMCID: PMC2938805 DOI: 10.1111/j.1476-5381.2010.00751.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 01/18/2010] [Accepted: 01/20/2010] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE RhoA kinase (ROCK) participates in K(+) depolarization (KCl)-induced Ca(2+) sensitization of contraction. Whether constitutive, depolarization- or Ca(2+)-activated ROCK plays the major role in this signalling system remains to be determined. Here, we determined whether Bay K 8644, a dihydropyridine that promotes Ca(2+) channel clusters to operate in a persistent Ca(2+) influx mode, could cause ROCK-dependent Ca(2+) sensitization. EXPERIMENTAL APPROACH Renal and femoral artery rings from New Zealand white rabbits were contracted with Bay K 8644. Tissues were frozen and processed to measure active RhoA and ROCK substrate (myosin phosphatase targeting subunit, MYPT1) and myosin light chain (MLC) phosphorylation, or loaded with fura-2 to measure intracellular free Ca(2+) ([Ca(2+)](i)). Effects of selective inhibitors of contraction were assessed in resting (basal) tissues and those contracted with Bay K 8644. KEY RESULTS Bay K 8644 produced strong increases in [Ca(2+)](i), MLC phosphorylation and tension, but not in MYPT1 phosphorylation. ROCK inhibition by H-1152 abolished basal MYPT1-pT853, diminished basal MLC phosphorylation and inhibited Bay K 8644-induced increases in MLC phosphorylation and tension. MLC kinase inhibition by wortmannin abolished Bay K 8644-induced contraction and increase in MLC phosphorylation but did not inhibit basal MYPT1-pT853. H-1152 and wortmannin had no effect on MYPT1-pT696, but 1 microM staurosporine inhibited basal MYPT1-pT853, MYPT1-pT696 and MLC phosphorylation. CONCLUSIONS AND IMPLICATIONS These data suggest that the constitutive activities of ROCK and a staurosporine-sensitive kinase regulate basal phosphorylation of MYPT1, which participates along with activation of MLC kinase in determining the strength of contraction induced by the Ca(2+) agonist, Bay K 8644.
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Affiliation(s)
- S M Alvarez
- Departments of Biochemistry and Molecular Biology and Pediatrics, Virginia Commonwealth University, School of Medicine, Richmond, VA, USA
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Role of Rho-kinase in mediating contraction of chicken embryo femoral arteries. J Comp Physiol B 2010; 180:427-35. [PMID: 19936759 PMCID: PMC2820664 DOI: 10.1007/s00360-009-0420-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 09/09/2009] [Accepted: 11/03/2009] [Indexed: 01/05/2023]
Abstract
Rho-kinase-dependent Ca2+ sensitization is an essential process for contraction of mammalian vascular smooth muscle but the information about its effects in non-mammalian vessels is scarce. We aimed to investigate, using the Rho-kinase inhibitor hydroxyfasudil, the potential role of the Rho-kinase pathway of Ca2+ sensitization in depolarization- and agonist-mediated contraction of chicken embryo (at day 19 of the 21 days of incubation) femoral arteries. Contraction elicited by KCl (125 mM) comprised two phases (phasic and tonic contraction), both of which were abolished in the absence of extracellular Ca2+. Hydroxyfasudil (10 microM) left the initial phasic component nearly intact but abolished the tonic component. Hydroxyfasudil also induced a marked impairment of the contractions elicited by phenylephrine (PE), the thromboxane A2 mimetic U46619, and endothelin-1. In contrast, inhibition of protein kinase C (PKC) by chelerythrine did not affect KCl- or PE-induced contractions, indicating lack of participation of PKC-mediated Ca2+ sensitization. Incubation under chronic hypoxia (15% O2 from day 0) impaired embryonic growth but did not significantly affect hydroxyfasudil-mediated relaxation. In summary, our findings are indicative of a role for Rho-kinase activity in depolarization- and agonist-induced force generation in chicken embryo femoral arteries.
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Abstract
The pyeloureteral function is to transport urine from the kidneys into the ureter toward the urinary bladder for storage until micturition. A set of mechanisms collaborates to achieve this purpose: the basic process regulating ureteral peristalsis is myogenic, initiated by active pacemaker cells located in the renal pelvis. Great emphasis has been given to hydrodynamic factors, such as urine flow rate in determining the size and pattern of urine boluses which, in turn, affect the mechanical aspects of peristaltic rhythm, rate, amplitude, and baseline pressure. Neurogenic contribution is thought to be limited to play a modulatory role in ureteral peristalsis. The myogenic theory of ureteral peristalsis can be traced back to Engelmann (1) who was able to localize the peristaltic pressure wave's origin in the renal pelvis and suggested that the ureteral contraction impulse passes from one ureteral cell to another, the whole ureter working as a functional syncitium. Recent studies of ureteral biomechanics, smooth muscle cell electrophysiology, membrane ionic currents, cytoskeletal components and pharmacophysiology much improved our understanding of the mechanism of how the urine bolus is propelled, how this process is disturbed in pathological states, and what could be done to improve it.
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Affiliation(s)
- F Osman
- Department of Urology and Clinical Experimental Research Department, Semmelweis University, Budapest, Hungary.
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Noguchi-Yachide T, Dodo K, Aoyama H, Fujimoto H, Hori M, Hashimoto Y, Kobayashi H. Identification of Binding Proteins of Fusarielin A as Actin and Tubulin. Chem Pharm Bull (Tokyo) 2010; 58:129-34. [DOI: 10.1248/cpb.58.129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | | | - Hiroshi Aoyama
- Institute of Molecular and Cellular Biosciences, The University of Tokyo
| | - Haruka Fujimoto
- Institute of Molecular and Cellular Biosciences, The University of Tokyo
| | - Masatoshi Hori
- Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Yuichi Hashimoto
- Institute of Molecular and Cellular Biosciences, The University of Tokyo
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Bai Y, Sanderson MJ. The contribution of Ca2+ signaling and Ca2+ sensitivity to the regulation of airway smooth muscle contraction is different in rats and mice. Am J Physiol Lung Cell Mol Physiol 2009; 296:L947-58. [PMID: 19346434 DOI: 10.1152/ajplung.90288.2008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To determine the relative contributions of Ca(2+) signaling and Ca(2+) sensitivity to the contractility of airway smooth muscle cells (SMCs), we compared the contractile responses of mouse and rat airways with the lung slice technique. Airway contraction was measured by monitoring changes in airway lumen area with phase-contrast microscopy, whereas changes in intracellular calcium concentration ([Ca(2+)](i)) of the SMCs were recorded with laser scanning microscopy. In mice and rats, methacholine (MCh) or serotonin induced concentration-dependent airway contraction and Ca(2+) oscillations in the SMCs. However, rat airways demonstrated greater contraction compared with mice, in response to agonist-induced Ca(2+) oscillations of a similar frequency. Because this indicates that rat airway SMCs have a higher Ca(2+) sensitivity compared with mice, we examined Ca(2+) sensitivity with Ca(2+)-permeabilized airway SMCs in which the [Ca(2+)](i) was experimentally controlled. In the absence of agonists, high [Ca(2+)](i) induced a sustained contraction in rat airways but only a transient contraction in mouse airways. This sustained contraction of rat airways was relaxed by Y-23672, a Rho kinase inhibitor, but not affected by GF-109203X, a PKC inhibitor. The subsequent exposure of Ca(2+)-permeabilized airway SMCs, with high [Ca(2+)](i), to MCh elicited a further contraction of rat airways and initiated a sustained contraction of mouse airways, without changing the [Ca(2+)](i) of the SMCs. Collectively, these results indicate that airway SMCs of rats have a substantially higher innate Ca(2+) sensitivity than mice and that this strongly influences the transduction of the frequency of Ca(2+) oscillations into the contractility of airway SMCs.
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Affiliation(s)
- Yan Bai
- Dept. of Physiology, Univ. of Massachusetts Medical School, 55 Lake Ave. North, Worcester, MA 01655, USA
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32
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Ohama T, Hori M, Fujisawa M, Kiyosue M, Hashimoto M, Ikenoue Y, Jinno Y, Miwa H, Matsumoto T, Murata T, Ozaki H. Downregulation of CPI-17 contributes to dysfunctional motility in chronic intestinal inflammation model mice and ulcerative colitis patients. J Gastroenterol 2009; 43:858-65. [PMID: 19012039 DOI: 10.1007/s00535-008-2241-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Accepted: 06/26/2008] [Indexed: 02/04/2023]
Abstract
BACKGROUND Chronic intestinal inflammation is frequently accompanied by motility disorders. We previously reported that proinflammatory cytokines, such as tumor necrosis factor alpha and interleukin (IL)-1beta downregulate CPI-17, an endogenous inhibitor of serine/threonine protein phosphatase in smooth-muscle cells, which results in the inhibition of myosin light chain phosphorylation and contractility. However, its clinical relevance has not been clarified. METHODS The present study examined the changes in CPI-17 expression in chronic intestinal inflammation using smooth-muscle tissues from IL-10 knockout mice and from patients with ulcerative colitis (UC). RESULTS The IL-10 knockout mice developed spontaneous and chronic colitis accompanied by immune cell infiltration, submucosal fibrosis, and thickening of the muscularis externa. The expression of alpha-smooth muscle actin protein in the smooth-muscle layer did not change, whereas that of CPI-17 protein was decreased by about 40% compared with healthy wild-type controls. Consistent with this observation, smooth-muscle contractile force and myosin light chain phosphorylation induced by a muscarinic agonist were reduced in the knockout mice. Moreover, we observed that CPI-17 protein expression was decreased in smooth-muscle tissues from patients with UC compared with controls. CONCLUSIONS CPI-17 downregulation might contribute to the decreased motor function in chronic inflammatory bowel diseases.
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Affiliation(s)
- Takashi Ohama
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Prakash J, de Borst MH, Lacombe M, Opdam F, Klok PA, van Goor H, Meijer DKF, Moolenaar F, Poelstra K, Kok RJ. Inhibition of renal rho kinase attenuates ischemia/reperfusion-induced injury. J Am Soc Nephrol 2008; 19:2086-97. [PMID: 18650485 DOI: 10.1681/asn.2007070794] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Rho kinase pathway plays an important role in dedifferentiation of epithelial cells and infiltration of inflammatory cells. For testing of the hypothesis that blockade of this cascade within the kidneys might be beneficial in the treatment of renal injury the Rho kinase inhibitor, Y27632 was coupled to lysozyme, a low molecular weight protein that is filtered through the glomerulus and is reabsorbed in proximal tubular cells. Pharmacokinetic studies with Y27632-lysozyme confirmed that the conjugate rapidly and extensively accumulated in the kidney. Treatment with Y27632-lysozyme substantially inhibited ischemia/reperfusion-induced tubular damage, indicated by reduced staining of the dedifferentiation markers kidney injury molecule 1 and vimentin, and increased E-cadherin relative to controls. Rho kinase activation was inhibited by Y27632-lysozyme within tubular cells and the interstitium. Y27632-lysozyme also inhibited inflammation and fibrogenesis, indicated by a reduction in gene expression of monocyte chemoattractant protein 1, procollagen Ialpha1, TGF-beta1, tissue inhibitor of metalloproteinase 1, and alpha-smooth muscle actin. Immunohistochemistry revealed reduced macrophage infiltration and decreased expression of alpha-smooth muscle actin, collagen I, collagen III, and fibronectin. In contrast, unconjugated Y27632 did not have these beneficial effects but instead caused systemic adverse effects, such as leukopenia. Neither treatment improved renal function in the bilateral ischemia/reperfusion model. In conclusion, the renally targeted Y27632-lysozyme conjugate strongly inhibits tubular damage, inflammation, and fibrogenesis induced by ischemia/reperfusion injury.
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Affiliation(s)
- Jai Prakash
- Department of Pharmacokinetics and Drug Delivery, Groningen Research Institute for Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, Netherlands.
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Hashiba Y, Tosaka M, Saito N, Imai H, Shimizu T, Sasaki T. Vasorelaxing effect of the Rho-kinase inhibitor, Y-27632, in isolated canine basilar arteries. Neurol Res 2007; 29:485-9. [PMID: 17806208 DOI: 10.1179/016164107x164076] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Increased calcium sensitization mediated by Rho/Rho-kinase may be important in the pathogenesis of cerebral vasospasm. The effects of a highly selective Rho-kinase inhibitor, Y-27632, were investigated on spasmogen-induced contractions of canine basilar artery. METHODS Typical spasmogenic substances present after subarachnoid hemorrhage (SAH), including prostaglandin F2a (PGF2a), 12-deoxyphorbol 13-isobutyrate (DPB), sphingosylpho-sphorylcholine (SPC) and high K+, were used in the study. Isometric tension was recorded in canine basilar artery rings in vitro. Intracellular calcium concentration ([Ca2+]i) and contraction force were measured simultaneously in fura-2-loaded canine basilar artery strips. The myosin light chain (MLC) phosphorylation levels were measured by glycerol gel electrophoresis followed by Western blotting. RESULTS Isometric tension recording revealed that the Rho-kinase inhibitor, Y-27632, dose-dependently inhibited vasocontraction induced by PGF2a and SPC, but not that induced by DPB. Simultaneous recordings of [Ca2+]i and tension revealed that the vasorelaxing effect of Y-27632 was not associated with changes in [Ca2+]i, suggesting that Y-27632 may inhibit calcium sensitization. Vasocontraction induced by DPB was not inhibited by Y-27632, but was inhibited by staurosporine. Phosphorylation of MLC was increased by PGF2a and SPC, and significantly inhibited by Y-27632, whereas such phosphorylation was increased by DPB, but not significantly inhibited by Y-27632. DISCUSSION Several spasmogenic mediators released after SAH may cause vasospasm through Rho-kinase-mediated increase in calcium sensitization. Rho-kinase inhibitors, including Y-27632, may be effective for the prevention of cerebral vasospasm after SAH.
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Affiliation(s)
- Yasuhiro Hashiba
- Department of Neurosurgery, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.
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Allahdadi KJ, Walker BR, Kanagy NL. ROK contribution to endothelin-mediated contraction in aorta and mesenteric arteries following intermittent hypoxia/hypercapnia in rats. Am J Physiol Heart Circ Physiol 2007; 293:H2911-8. [PMID: 17720771 DOI: 10.1152/ajpheart.00217.2007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We reported previously that intermittent hypoxia with CO(2) to maintain eucapnia (IH-C) elevates plasma endothelin-1 (ET-1) and arterial pressure. In small mesenteric arteries (sMA; inner diameter = 150 microm), IH-C augments ET-1 constrictor sensitivity but diminishes ET-1-induced increases in intracellular Ca(2+) concentration, suggesting IH-C exposure increases both ET-1 levels and ET-1-stimulated Ca(2+) sensitization. Because Rho-associated kinase (ROK) can mediate Ca(2+) sensitization, we hypothesized that augmented vasoconstrictor sensitivity to ET-1 in arteries from IH-C-exposed rats is dependent on ROK activation. In thoracic aortic rings, ET-1 contraction was not different between groups, but ROK inhibition (Y-27632, 3 and 10 microM) attenuated ET-1 contraction more in IH-C than in sham arteries (50 +/- 11 and 78 +/- 7% vs. 41 +/- 12 and 48 +/- 9% inhibition, respectively). Therefore, ROK appears to contribute more to ET-1 contraction in IH-C than in sham aorta. In sMA, ROK inhibitors did not affect ET-1-mediated constriction in sham arteries and only modestly inhibited it in IH-C arteries. In ionomycin-permeabilized sMA with intracellular Ca(2+) concentration held at basal levels, Y-27632 did not affect ET-1-mediated constriction in either IH-C or sham sMA and ET-1 did not stimulate ROK translocation. In contrast, inhibition of myosin light-chain kinase (ML-9, 100 microM) prevented ET-1-mediated constriction in sMA from both groups. Therefore, IH-C exposure increases ET-1 vasoconstrictor sensitivity in sMA but not in aorta. Furthermore, ET-1 constriction is myosin light-chain kinase dependent and mediated by Ca(2+) sensitization that is independent of ROK activation in sMA but not aorta. Thus ET-1-mediated signaling in aorta and sMA is altered by IH-C but is dependent on different second messenger systems in small vs. large arteries.
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Affiliation(s)
- Kyan J Allahdadi
- Department of Cell Biology and Physiology, Vascular Physiology Group, University of New Mexico, Albuquerque, New Mexico 87131, USA
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36
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Abstract
A better understanding of the mechanisms that generate and modulate uterine contractility is needed if progress is to be made in the prevention or treatment of problems in labour. Dysfunctional labour describes the condition when uterine contractility is too poor to dilate the cervix, and it is the leading cause of emergency Caesarean sections. Recently, insight has been gained into a possible causal mechanism for dysfunctional labour. Study of the physiological mechanisms that produce excitation in the uterus, the subsequent Ca(2)(+) signals and biochemical pathway leading to contraction has underpinned this progress. In this review, I give an account of excitation-contraction signalling in the myometrium and explore the implications of recent findings concerning lipid rafts for these processes. I also discuss how changes of pH are fundamentally enmeshed in uterine activity and biochemistry and explore the effect that pH changes will have on human myometrium. Finally, I present the evidence that acidification of the myometrium is correlated with dysfunctional labour and suggest the processes by which it is occurring. It is only by gaining a better understanding of uterine physiology and pathophysiology that progress will be made and research findings translated into clinical benefit for women and their families.
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Affiliation(s)
- Susan Wray
- Department of Physiology, University of Liverpool, Crown Street, Liverpool L69 3BX, UK.
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Wardle RL, Gu M, Ishida Y, Paul RJ. Rho kinase is an effector underlying Ca2+-desensitizing hypoxic relaxation in porcine coronary artery. Am J Physiol Heart Circ Physiol 2007; 293:H23-9. [PMID: 17416603 DOI: 10.1152/ajpheart.01158.2006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acute hypoxia dilates most systemic arteries leading to increased tissue perfusion. We have previously shown that at high-stimulus conditions, porcine coronary artery was relaxed by hypoxia without a change in intracellular [Ca2+] ( 27 ). This Ca2+-desensitizing hypoxic relaxation (CDHR) was validated in permeabilized porcine coronary artery smooth muscle (PCASM) in which hypoxia decreased force and myosin regulatory light chain phosphorylation (p-MRLC) despite fixed [Ca2+] ( 10 ). Rho kinase-dependent phosphorylation of myosin phosphatase-targeting subunit 1 (p-MYPT1) is associated with decreased MRLC phosphatase activity and increased Ca2+ sensitivity of both p-MRLC and force. We recently reported that p-MYPT1 dephosphorylation was a key effector in CDHR ( 33 ). In the current study, we tested the hypothesis that Rho kinase and not p-MYPT1 phosphatase is the regulated enzyme involved in CDHR. We used α-toxin to permeabilize deendothelialized PCASM. CDHR was attenuated in contractions attributable to myosin light chain kinase (MLCK, in the presence of the Rho kinase inhibitor Y-27632). In contrast, hypoxia relaxed contractions attributable to Rho kinase phosphorylation of MYPT1 and MRLC or MRLC alone (in the presence of the MLCK inhibitor ML7). Using an in situ assay, we showed that Rho kinase activity, measured as thiophosphorylation of MYPT1 and MRLC, was nearly abolished by hypoxia. The in vitro activity of the catalytically active fragment of Rho kinase was not affected by hypoxia. Our evidence strongly implicates that hypoxia directly inhibits Rho kinase-dependent phosphorylation of MYPT1. This underlies the decreases in both p-MYPT1 and p-MRLC and thereby leads to the Ca2+-desensitizing hypoxic relaxation.
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Affiliation(s)
- Robert L Wardle
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267-0576, USA
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38
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Rajasekaran M, Mehta N, Baquir A, Kuntz S. Rho-kinase inhibition suppresses potassium chloride-induced bladder hyperactivity in a rat model. Urology 2007; 69:791-4. [PMID: 17445683 DOI: 10.1016/j.urology.2007.01.071] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 11/21/2006] [Accepted: 01/23/2007] [Indexed: 11/18/2022]
Abstract
OBJECTIVES The molecular mechanisms by which potassium induces urinary bladder hyperactivity are not clear. In the present study, we tested our hypothesis that potassium chloride (KCl)-induced bladder hyperactivity might be mediated through a calcium-sensitizing RhoA-Rho-kinase pathway in an in vivo animal model using urodynamic parameters. METHODS Two groups of adult male rats (n = 8) were anesthetized, their bladder exteriorized, and a saline-filled Intracath fixed into the bladder dome. This Intracath was connected to a pressure transducer and an infusion pump. Continuous filling cystometrograms were performed by infusing warm saline (0.04 mL/min) to obtain baseline data on each rat. The number of contractions per unit time (intercontractile intervals in seconds), pressure threshold, and peak pressure during micturition were recorded. To create bladder hyperactivity, protamine sulfate (30 mg/mL) followed by KCl (500 mM) was infused intravesically, and a continuous filling cystometrogram was again recorded. Y-27632, a specific RhoA-Rho-kinase inhibitor, was administered either intra-arterially (group 1) or intravesically (group 2) to each rat, and an additional continuous filling cystometrogram was recorded with KCl (500 mM) to observe the effects of Rho-kinase inhibition on bladder contractility. RESULTS Intravesical KCl infusion after protamine exposure resulted in significantly greater contractions and decreased the intercontractile interval (P <0.05). Y-27632 administration attenuated the effect of KCl on the contractions and intercontractile interval and decreased the mean pressure threshold. CONCLUSIONS Suppression of KCl-induced bladder contractility by the Rho-kinase inhibitor Y-27632 confirmed the involvement of this novel calcium-sensitizing RhoA-Rho-kinase pathway in mediating these smooth muscle contractions.
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Affiliation(s)
- Mahadevan Rajasekaran
- Division of Urology, University of California, San Diego, Medical Center, San Diego, California 92103-8897, USA.
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Lee CK, Kim J, Won KJ, Lee HM, Kim HJ, Roh HY, Park HJ, Shin HS, Park TK, Kim B, Lee SM. Phorbol ester-induced contraction through p38 mitogen-activated protein kinase is diminished in aortas from DOCA-salt hypertensive rats. Arch Pharm Res 2006; 29:1024-31. [PMID: 17146972 DOI: 10.1007/bf02969287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The role of mitogen-activated protein kinase (MAPK) in the decreased contractile response to phorbol ester in aortic smooth muscle strips from deoxycorticosterone acetate (DOCA)-salt hypertensive rats was examined. Norepinephrine (NE) evoked greater contractility in aortic strips from DOCA rats than in those of sham-operated rats. 12-Deoxyphorbol 13-isobutyrate (DPB) induced contraction in Ca2+-free medium, which was diminished in strips from DOCA rats compared to sham-operated rats. Vasoconstrictions induced by these stimulants were inhibited by SB203580 and PD098059, inhibitors of p38 MAPK and extracellular signal-regulated kinase (ERK) 1/2, respectively, in both strips. The phosphorylation of p38 MAPK and ERK1/2 induced by NE was greater in strips from DOCA rats compared to those from sham-operated rats, and this phosphorylation was inhibited by the kinase inhibitors. DPB increased the phosphorylation of p38 MAPK and ERK1/2 in strips from both animals, and the increment of p38 MAPK phosphorylation by the stimulant was diminished in strips from DOCA rats compared to sham-operated rats. These findings suggest that the Ca2+-independent contraction evoked by DPB results from the activation of MAPKs in rat aortic smooth muscle and that the attenuated contractility by DPB in DOCA rat appears to be associated with diminished p38 MAPK activity.
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Affiliation(s)
- Chang-Kwon Lee
- Department of Physiology, College of Medicine, Konkuk University, Chungju 380-701, Korea
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Yoshioka K, Sugimoto N, Takuwa N, Takuwa Y. Essential Role for Class II Phosphoinositide 3-kinase α-Isoform in Ca2+-Induced, Rho- and Rho Kinase-Dependent Regulation of Myosin Phosphatase and Contraction in Isolated Vascular Smooth Muscle Cells. Mol Pharmacol 2006; 71:912-20. [PMID: 17179444 DOI: 10.1124/mol.106.032599] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The laser confocal fluorescent microscope-based observation of contractile responses in green fluorescent protein-expressing differentiated vascular smooth muscle cells, combined with the RNA interference-mediated gene-silencing technique, allowed us to determine the role of phosphoinositide 3-kinase (PI3K) class II alpha-isoform (PI3K-C2alpha) as a novel, Ca2+-dependent regulator of myosin light-chain phosphatase (MLCP) and contraction. The Ca2+-ionophore ionomycin induced a robust contractile response with an increase in the intracellular free Ca2+ concentration ([Ca2+]i). The PI3K-C2alpha-specific short interfering RNA (siRNA) induced a selective and marked reduction in PI3K-C2alpha protein expression. The siRNA-mediated knockdown of PI3K-C2alpha, but not class I PI3K p110alpha, suppressed ionomycin-induced contraction without altering Ca2+-mobilization. PI3K-C2alpha is uniquely less sensitive to the PI3K inhibitor 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002) than the other PI3K members, including p110alpha. Ionomycin-induced contraction was inhibited only by a relatively high concentration of LY294002. Consistent with our previous observations showing that ionomycin and membrane depolarization induced Rho activation in vascular smooth muscle tissues in a Ca2+-dependent manner, ionomycin-induced contraction was dependent on Rho and Rho-kinase. Ionomycin induced phosphorylation of the MLCP-regulatory subunit myosin targeting protein 1(MYPT1) at Thr850 and the 20-kDa myosin light chain (MLC) in a Rho kinase-dependent manner. Knockdown of PI3K-C2alpha suppressed phosphorylation of both MYPT1 and MLC. The receptor agonist noradrenaline, which induced a rapid increase in the [Ca2+]i and Ca2+-dependent contraction, stimulated phosphorylation of MYPT1 and MLC, which was also dependent on Ca2+, PI3K-C2alpha, and Rho-kinase. These observations indicate that PI3K-C2alpha is necessary for Ca2+-induced Rho- and Rho kinase-dependent negative regulation of MLCP and consequently MLC phosphorylation and contraction.
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Affiliation(s)
- Kazuaki Yoshioka
- Department of Physiology, Kanazawa University Graduate School of Medicine, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan
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41
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Hung GHY, Jones RL, Lam FFY, Chan KM, Hidaka H, Suzuki M, Sasaki Y. Investigation of the pronounced synergism between prostaglandin E2 and other constrictor agents on rat femoral artery. Prostaglandins Leukot Essent Fatty Acids 2006; 74:401-15. [PMID: 16737803 DOI: 10.1016/j.plefa.2006.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Revised: 03/22/2006] [Accepted: 04/11/2006] [Indexed: 11/29/2022]
Abstract
This study investigates the pronounced synergism between the weak contractile action of prostaglandin E(2) (PGE(2)) and strong actions of phenylephrine, U-46619 and K(+) on rat isolated femoral artery. The potency ranking for synergism was SC-46275 (prostanoid receptor agonist selectivity: EP(3)>>EP(1))=sulprostone (EP(3)>EP(1))>17-phenyl PGE(2) (EP(1)>EP(3)). The novel EP(3) antagonist L-798106 (0.2-1microM) blocked the enhanced action of sulprostone (pA(2)=7.35-8.10), while the EP(1) antagonist SC-51322 (1microM) did not (pA(2)<6.0). Matching responses to priming agent and priming agent/sulprostone were similarly suppressed by nifedipine (300nM) and the selective Rho-kinase inhibitors H-1152 (0.1-1microM) and Y-27632 (1-10microM). Our findings implicate an EP(3) receptor in the prostanoid component of contractile synergism. While the synergism predominantly operates through a Ca(2+) influx-Rho-kinase pathway, the EP(3) receptor does not necessarily transduce via Rho-kinase.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Alprostadil/analogs & derivatives
- Alprostadil/pharmacology
- Animals
- Dinoprostone/analogs & derivatives
- Dinoprostone/analysis
- Dinoprostone/pharmacology
- Drug Interactions
- Drug Synergism
- Femoral Artery/drug effects
- In Vitro Techniques
- Intracellular Signaling Peptides and Proteins
- Male
- Nifedipine/pharmacology
- Phenylephrine/pharmacology
- Potassium/pharmacology
- Prostaglandins F, Synthetic/pharmacology
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Rats
- Rats, Sprague-Dawley
- Receptors, Prostaglandin/agonists
- Receptors, Prostaglandin/metabolism
- Receptors, Prostaglandin E/agonists
- Receptors, Prostaglandin E/antagonists & inhibitors
- Receptors, Prostaglandin E/metabolism
- Receptors, Prostaglandin E, EP1 Subtype
- Receptors, Prostaglandin E, EP3 Subtype
- Sensitivity and Specificity
- Sulfonamides/metabolism
- Vasoconstrictor Agents/pharmacology
- rho-Associated Kinases
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Affiliation(s)
- Gloria H Y Hung
- Department of Pharmacology, Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
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42
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Amobi NIB, Chung IP, Smith ICH. Attenuation of contractility in rat epididymal vas deferens by Rho kinase inhibitors. ACTA ACUST UNITED AC 2006; 26:169-81. [PMID: 16553645 DOI: 10.1111/j.1474-8673.2006.00367.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The involvement of Ca(2+) sensitization mediated through Rho kinase in the contractility of rat epididymal vas deferens was investigated using Rho kinase inhibitors, trans-4-[(1R)-1-aminoethyl]-N-4-pyridinilcyclohexanecarboxamide dihydrochloride (Y-27632) and 1-(5-isoquinolinesulphonyl)homopiperazine (HA 1077), in comparison with myosin light chain kinase (MLCK) inhibitors, wortmannin and 1-(5-chloronaphthalenesulphonyl)homopiperazine (ML-9) and agents that affect protein kinase C (PKC) and non-receptor tyrosine kinase intracellular signalling. 2 In Ca(2+)-free/ethyleneglycol-bis-(beta-aminoethylether)N,N,N('),N(')-tetraacetic acid (EGTA) (1 mM) medium, noradrenaline evoked sustained contractions. Y-27632 and HA 1077 caused a concentration-dependent inhibition and complete relaxation (IC(50), 1.08 and 1.75 microM respectively). The Ca(2+)-free contraction was reduced by wortmannin (10 microM) or ML-9 (10 microM) but not by inhibitors of diacylglycerol metabolism, 3-[2-[4[bis(4-Fluoropheny)methylene]-1-piperidinyl]-2,3-dihydro-2-thioxi-4(H)-quinazolinone (R59949) (10 microm) or 1,6-bis(cyclohexyloximinocarbonylamino)hexane (RHC-80267) (10 microM) or by the phospholipase A(2) (PLA(2)) inhibitor, quinacrine (up to 100 microM) or tyrosine kinase inhibitor, genistein (30 microM). 3 In the presence of Ca(2+) (2.5 mM), noradrenaline (100 microM) evoked rhythmic activity and biphasic tonic contractions. Y-27632 (1-10 microM) or HA 1077 (1-10 microM) reduced the amplitude of rhythmic activity and tonic contractions. ML-9 (10 microM) attenuated the occurrence of rhythmic activity and modestly reduced the tonic contractions. ML-9 (10 microM) combined with Y-27632 (10 microM) significantly reduced the tonic contractions. ML-9 (30 microM) alone (or combined with Y-27632 10 microM) suppressed the rhythmic activity and substantially reduced (or abolished) the tonic contractions. 4 Contractions evoked by high [K(+)](o) (120 mM) or alpha,beta-methylene ATP (10 microM) were reduced significantly by Y-27632 (1-3 microM) indicating that the Rho kinase signalling pathway is activated by direct tissue depolarization or by stimulation of ligand-gated P(2X) purinoceptors. 5 Collectively, these results indicate that Ca(2+)-sensitization mediated by Rho kinase is involved in agonist- or depolarization-induced contraction of rat epididymal vas deferens. It is the major contractile mechanism underlying noradrenaline-induced Ca(2+)-free responses. It contributes to Ca(2+)-dependent rhythmic contractility and optimizes the development of full contractile tension triggered through calmodulin/MLCK activation by stimulated influx of Ca(2+).
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Affiliation(s)
- N I B Amobi
- King's College London, Division of Biomedical Science Research, Guys Campus, London SE1 1UL, UK
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Hennenberg M, Biecker E, Trebicka J, Jochem K, Zhou Q, Schmidt M, Jakobs KH, Sauerbruch T, Heller J. Defective RhoA/Rho-kinase signaling contributes to vascular hypocontractility and vasodilation in cirrhotic rats. Gastroenterology 2006; 130:838-54. [PMID: 16530523 DOI: 10.1053/j.gastro.2005.11.029] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Accepted: 11/16/2005] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Portal hypertension is associated with arterial hypotension and vascular hypocontractility, which persists despite elevated plasma levels of vasoconstrictors. We investigated the role of the RhoA/Rho-kinase pathway in vascular smooth muscle hypocontractility of rats with secondary biliary cirrhosis. METHODS Aortic expressions of RhoA and Rho-kinase were analyzed in sham-operated and BDL rats by reverse-transcription polymerase chain reaction (RT-PCR) and immunoblots. Activation of aortic RhoA was examined by pull down of guanosine triphosphate (GTP)-RhoA and membrane translocation of RhoA. Rho-kinase activity was assessed as phosphorylation of its substrate, moesin. Contractility of isolated aortic rings was determined myographically. The hemodynamic effect of the Rho-kinase inhibitor (R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide (Y-27632) was determined in vivo by measuring changes in mean arterial pressure and systemic vascular resistance (SVR) (microspheres). RESULTS Contraction of aortic rings from BDL rats was impaired in response to the alpha(1)-adrenergic receptor agonist methoxamine but not to high molar KCl. Aortic expression of RhoA was unchanged in cirrhotic rats, whereas Rho-kinase was down-regulated posttranscriptionally. Methoxamine-induced activation of RhoA as well as basal and methoxamine-induced phosphorylation of moesin were strongly reduced in aortas from cirrhotic rats. Aortic rings from cirrhotic rats precontracted with methoxamine showed an increased sensitivity to relaxation with Y-27632. The drop in SVR induced by Y-27632 was larger in cirrhotic rats than in sham-operated rats. CONCLUSIONS An impaired vascular activation of RhoA and a down-regulation of Rho-kinase might contribute to vasodilation and vascular hypocontractility in BDL-induced cirrhosis.
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Affiliation(s)
- Martin Hennenberg
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
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Quinn T, Feighery R, Baird AW. Role of Rho-kinase in guinea-pig gallbladder smooth muscle contraction. Eur J Pharmacol 2006; 534:210-7. [PMID: 16499905 DOI: 10.1016/j.ejphar.2006.01.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 12/19/2005] [Accepted: 01/11/2006] [Indexed: 10/25/2022]
Abstract
Guinea-pig gallbladder smooth muscle contractions can be elicited pharmacologically by a range of mechanisms. The involvement of Rho-kinase in contractions mediated by receptor-dependent and receptor-independent mechanisms was investigated using the Rho-kinase inhibitor (+)-(R)-trans-4-(1-aminoethyl)-N-(4-pyridyl) cyclohexane carboxamide (Y-27632). In a separate series of experiments, the role of Rho-kinase in the contractile response to Ca2+ entry through store-operated Ca2+ channels and to electrical field stimulation was also examined. Y-27632 (10 microM), which caused a significant decrease (P<0.0005) in basal resting tone, significantly inhibited gallbladder contractions evoked by cumulative additions of the G-protein-coupled agonists, carbachol (1 nM-100 microM; P<0.05) and cholecystokinin (10 nM-1 microM; P<0.005). Y-27632 also inhibited the contractions evoked by a single addition of the sarcoplasmic reticulum ATPase inhibitor, thapsigargin (1 microM; P<0.0005) and cumulative additions of KCl (10-85 mM; P<0.0005). The contractile response to Ca2+ entry through store-operated Ca2+ channels was significantly inhibited by Y-27632 (P<0.05) as were the contractile responses evoked by electrical field stimulation (2-25 Hz; P<0.0005). In contrast, Y-27632 had no significant effect on contractions evoked by phorbol 12,13-dibutyrate (0.1 nM-1 microM; a protein kinase C activator) or by the phosphatase inhibitor, cantharidin (100 microM). In conclusion, Rho-kinase contributes to the contractile response in guinea-pig gallbladder smooth muscle evoked by both G-protein-coupled and non-G-protein-coupled mechanisms in addition to contributing to the maintenance of basal tone. It also contributes to the contractile responses resulting from electrical field stimulation and store-operated Ca2+ channel entry.
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Affiliation(s)
- Teresa Quinn
- School of Agriculture, Food Science and Veterinary Medicine, Veterinary Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland
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Wardle RL, Gu M, Ishida Y, Paul RJ. Ca2+-desensitizing hypoxic vasorelaxation: pivotal role for the myosin binding subunit of myosin phosphatase (MYPT1) in porcine coronary artery. J Physiol 2006; 572:259-67. [PMID: 16439434 PMCID: PMC1779640 DOI: 10.1113/jphysiol.2005.104083] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Acute hypoxia dilates most systemic arteries leading to increased tissue perfusion. We showed that at high stimulus conditions, porcine coronary artery was relaxed by hypoxia without a change in [Ca(2+)](i). This 'Ca(2+)-desensitizing hypoxic relaxation' was validated in permeabilized porcine coronary artery smooth muscle (PCASM) in which hypoxia decreased force and myosin regulatory light chain phosphorylation (p-MRLC) despite fixed [Ca(2+)]. Rho kinase-dependent phosphorylation of MYPT1 (p-MYPT1) is associated with decreased MRLC phosphatase (MLCP) activity, and increased Ca(2+) sensitivity of both p-MRLC and force. We tested the hypothesis that hypoxia induces Ca(2+)-desensitizing hypoxic relaxation via dephosphorylation of p-MYPT1, consequently increasing MLCP activity and thus decreasing p-MRLC. alpha-Toxin-permeabilized PCASM pretreated with ATPgammaS did not relax in response to hypoxia. Moreover, when MRLC but not MYPT1 was protected from ATPgammaS thiophosphorylation by the MRLC kinase inhibitor ML7 (300 mum), hypoxia remained ineffective. In contrast, hypoxic relaxation was preserved with further addition of the Rho kinase inhibitor Y27632 (1 mum), to attenuate thiophosphorylation of MYPT1. Importantly, measurements of p-MRLC, and p-MYPT1 at T696 and T853 (human sequence) paralleled that of force. We conclude that Ca(2+)-desensitizing hypoxic relaxation requires dephosphorylation of p-MYPT1. Moreover, no kinases, other then those inhibited by ML7 and Y27632, nor their associated phosphoproteins can be involved in Ca(2+)-desensitizing hypoxic relaxation.
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Affiliation(s)
- Robert L Wardle
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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Choi WH, Kim J, Lee YR, Lee CK, Kim YS, Kim J, Choi YJ, Woo NS, Cho S, Kim B. Cdc42 contributes to phorbol ester-induced Ca2+-independent contraction of pulmonary artery smooth muscle. J Vet Med Sci 2006; 67:787-93. [PMID: 16141665 DOI: 10.1292/jvms.67.787] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We determined the contribution of the Rho family of low molecular GTP-binding proteins to phorbol ester-induced contraction in swine pulmonary artery smooth muscle. In Ca2+-free medium containing 1 mM EGTA, 12-deoxyphorbol 13-isobutyrate (DPB, 1 microM), a protein kinase C (PKC) activator, elicited sustained contractions, which were not inhibited by treatment with verapamil, a voltage-dependent Ca2+ channel antagonist, and Y27632, a Rho-associated kinase inhibitor. Immunoblot analysis showed three PKC isoforms (alpha, epsilon, and zeta) and two Rho GTPases (RhoA and Cdc42) in both cytosolic and the membrane fractions from quiescent strips. DPB (1 microM) significantly induced PKCalpha and epsilon to translocate from the cytosolic to the membrane fraction in Ca2+-free medium. DPB also elicited the translocation of Cdc42, but not RhoA to the membrane fraction. Similarly, in the experiment for measurement of Rho GTPase activity by pull-down assay, DPB (1 microM) significantly increased the activity of Cdc42 in Ca2+-free medium. Norepinephrine (NE, 10 microM) stimulated the redistribution of RhoA from the cytosolic to the membrane fraction in swine pulmonary artery smooth muscle. In contrast, NE did not alter the subcellular distributions of Cdc42 and the PKC isoforms. These results indicate that phorbol ester evokes PKC-mediated Ca2+-independent contraction via a Rho GTPase pathway, especially Cdc42, in smooth muscle from swine pulmonary arteries.
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Affiliation(s)
- Won-Ho Choi
- Department of Physiology and Anesthesiology, College of Medicine, Institute of Biomedical Science and Technology, Konkuk University, Choongju, Korea
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Porter M, Evans MC, Miner AS, Berg KM, Ward KR, Ratz PH. Convergence of Ca2+-desensitizing mechanisms activated by forskolin and phenylephrine pretreatment, but not 8-bromo-cGMP. Am J Physiol Cell Physiol 2006; 290:C1552-9. [PMID: 16421202 DOI: 10.1152/ajpcell.00534.2005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Contractile stimuli can sensitize myosin to Ca2+ by activating RhoA kinase (ROK) and PKC that inhibit myosin light chain phosphatase (MLCP) activity. Relaxant stimuli, acting through PKA and PKG (cyclic nucleotide-dependent protein kinases), and pretreatment with contractile agents such as phenylephrine (PE), can desensitize myosin to Ca2+. It is unknown precisely how these stimuli cause Ca2+ desensitization. To test the hypothesis that PKA, PKG, and PE pretreatment signaling systems converge to cause relaxation by inhibition of ROK in intact, isolated tissues, we examined the effects of forskolin (FSK; PKA activation), 8-bromo-cGMP (8br-cGMP; PKG activation), and PE pretreatment on KCl-induced force maintenance in rabbit arteries, a response nearly completely dependent on ROK activation. PE pretreatment and agents activating PKA and PKG caused Ca2+ desensitization by inhibiting KCl-induced tonic force and MLC phosphorylation without inhibiting intracellular [Ca2+]. At pCa 5 in beta-escin-permeabilized muscle, FSK and 8b-cGMP accelerated the relaxation rate when tissues were returned to pCa 9, suggesting that both agents can elevate MLCP activity. However, a component of the Ca2+ desensitization attributed to PKG activation in intact tissues appeared to involve a MLC phosphorylation-independent component. Inhibition of KCl-induced tonic force by the ROK inhibitor, Y-27632, and by PE pretreatment, were synergistically potentiated by 8b-cGMP, but not FSK. FSK and PE pretreatment, but not 8b-cGMP, inhibited the KCl-induced increase in site-specific myosin phosphatase target protein-1 phosphorylation at Thr853. These data support the hypothesis that PKA and PE pretreatment converge on a common Ca2+-desensitization pathway, but that PKG can act by a mechanism different from that activated by PKA and PE pretreatment.
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Affiliation(s)
- Melissa Porter
- Virginia Commonwealth Univ. School of Medicine, Dept of Biochemistry, 1101 E. Marshall St., PO Box 980614, Richmond, VA 23298-0614, USA
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Jin L, Burnett AL. RhoA/Rho-kinase in erectile tissue: mechanisms of disease and therapeutic insights. Clin Sci (Lond) 2006; 110:153-65. [PMID: 16411892 DOI: 10.1042/cs20050255] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Penile erection is a complicated event involving the regulation of corpus cavernosal smooth muscle tone. Recently, the small monomeric G-protein RhoA and its downstream effector Rho-kinase have been proposed to be important players for mediating vasoconstriction in the penis. RhoA/Rho-kinase increases MLC (myosin light chain) phosphorylation through inhibition of MLCP (MLC phosphatase) thereby increasing Ca2+ sensitivity. This review will outline the RhoA/Rho-kinase signalling pathway, including the upstream regulators, guanine nucleotide exchange factors, GDP dissociation inhibitors and GTPase-activating proteins. We also summarize the current knowledge about the physiological roles of RhoA/Rho-kinase in both male and female erectile tissues and its aberrations contributing to erectile dysfunction in several disease states. Understanding the RhoA/Rho-kinase signalling pathway in the regulation of erection is important for the development of therapeutic interventions for erectile dysfunction.
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Affiliation(s)
- Liming Jin
- Department of Urology, Johns Hopkins University, Baltimore, MD 21287, USA.
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Ward JPT, Knock GA, Snetkov VA, Aaronson PI. Protein kinases in vascular smooth muscle tone--role in the pulmonary vasculature and hypoxic pulmonary vasoconstriction. Pharmacol Ther 2005; 104:207-31. [PMID: 15556675 DOI: 10.1016/j.pharmthera.2004.08.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hypoxic pulmonary vasoconstriction (HPV) is an adaptive mechanism that in the normal animal diverts blood away from poorly ventilated areas of the lung, thereby maintaining optimal ventilation-perfusion matching. In global hypoxia however, such as in respiratory disease or at altitude, it causes detrimental increases in pulmonary vascular resistance and pulmonary artery (PA) pressure. The precise intracellular pathways and mechanisms underlying HPV remain unclear, although it is now recognised that both an elevation in smooth muscle intracellular [Ca2+] and a concomitant increase in Ca2+ sensitivity are involved. Several key intracellular protein kinases have been proposed as components of the signal transduction pathways leading to development of HPV, specifically Rho kinase, non-receptor tyrosine kinases (NRTK), p38 mitogen activated protein (MAP) kinase, and protein kinase C (PKC). All of these have been implicated to a greater or lesser extent in pathways leading to Ca2+ sensitisation, and in some cases regulation of intracellular [Ca2+] as well. In this article, we review the role of these key protein kinases in the regulation of vascular smooth muscle (VSM) constriction, applying what is known in the systemic circulation to the pulmonary circulation and HPV. We conclude that the strongest evidence for direct involvement of protein kinases in the mechanisms of HPV concerns a central role for Rho kinase in Ca2+ sensitisation, and a potential role for Src-family kinases in both modulation of Ca2+ entry via capacitative Ca2+ entry (CCE) and activation of Rho kinase, though others are likely to have indirect or modulatory influences. In addition, we speculate that Src family kinases may provide a central interface between the proposed hypoxia-induced generation of reactive oxygen species by mitochondria and both the elevation in intracellular [Ca2+] and Rho kinase mediated Ca2+ sensitisation.
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Affiliation(s)
- Jeremy P T Ward
- Division of Asthma, Allergy and Lung Biology, Guy's, King's and St Thomas' School of Medicine, King's College London, London, UK.
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Liu C, Zuo J, Pertens E, Helli PB, Janssen LJ. Regulation of Rho/ROCK signaling in airway smooth muscle by membrane potential and [Ca2+]i. Am J Physiol Lung Cell Mol Physiol 2005; 289:L574-82. [PMID: 15937065 DOI: 10.1152/ajplung.00134.2005] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recently, we have shown that Rho and Rho-activated kinase (ROCK) may become activated by high-millimolar KCl, which had previously been widely assumed to act solely through opening of voltage-dependent Ca(2+) channels. In this study, we explored in more detail the relationship between membrane depolarization, Ca(2+) currents, and activation of Rho/ROCK in bovine tracheal smooth muscle. Ca(2+) currents began to activate at membrane voltages more positive than -40 mV and were maximally activated above 0 mV; at the same time, these underwent time- and voltage-dependent inactivation. Depolarizing intact tissues by KCl challenge evoked contractions that were blocked equally, and in a nonadditive fashion, by nifedipine or by the ROCK inhibitor Y-27632. Other agents that elevate intracellular calcium concentration ([Ca(2+)](i)) by pathways independent of G protein-coupled receptors, namely the SERCA-pump inhibitor cyclopiazonic acid and the Ca(2+) ionophore A-23187, evoked contractions that were also largely reduced by Y-27632. KCl directly increased Rho and ROCK activities in a concentration-dependent fashion that paralleled closely the effect of KCl on tone and [Ca(2+)](i), as well as the voltage-dependent Ca(2+) currents that were measured over the voltage ranges that are evoked by 0-120 mM KCl. Through the use of various pharmacological inhibitors, we ruled out roles for Ca(2+)/calmodulin-dependent CaM kinase II, protein kinase C, and protein kinase A in mediating the KCl-stimulated changes in tone and Rho/ROCK activities. In conclusion, Rho is activated by elevation of [Ca(2+)](i) (although the signal transduction pathway underlying this Ca(2+) dependence is still unclear) and possibly also by membrane depolarization per se.
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Affiliation(s)
- Caiqiong Liu
- Asthma Research Group, Firestone Institute for Respiratory Health, St. Joseph's Hospital, Hamilton, Ontario, Canada L8N 4A6
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