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Han YS, Bandi R, Fogarty MJ, Sieck GC, Brozovich FV. Aging related decreases in NM myosin expression and contractility in a resistance vessel. Front Physiol 2024; 15:1411420. [PMID: 38808359 PMCID: PMC11130448 DOI: 10.3389/fphys.2024.1411420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 05/01/2024] [Indexed: 05/30/2024] Open
Abstract
Introduction: Vasodilatation in response to NO is a fundamental response of the vasculature, and during aging, the vasculature is characterized by an increase in stiffness and decrease in sensitivity to NO mediated vasodilatation. Vascular tone is regulated by the activation of smooth muscle and nonmuscle (NM) myosin, which are regulated by the activities of myosin light chain kinase (MLCK) and MLC phosphatase. MLC phosphatase is a trimeric enzyme with a catalytic subunit, myosin targeting subunit (MYPT1) and 20 kDa subunit of unknown function. Alternative mRNA splicing produces LZ+/LZ- MYPT1 isoforms and the relative expression of LZ+/LZ- MYPT1 determines the sensitivity to NO mediated vasodilatation. This study tested the hypothesis that aging is associated with changes in LZ+ MYPT1 and NM myosin expression, which alter vascular reactivity. Methods: We determined MYPT1 and NM myosin expression, force and the sensitivity of both endothelial dependent and endothelial independent relaxation in tertiary mesenteric arteries of young (6mo) and elderly (24mo) Fischer344 rats. Results: The data demonstrate that aging is associated with a decrease in both the expression of NM myosin and force, but LZ+ MYPT expression and the sensitivity to both endothelial dependent and independent vasodilatation did not change. Further, smooth muscle cell hypertrophy increases the thickness of the medial layer of smooth muscle with aging. Discussion: The reduction of NM myosin may represent an aging associated compensatory mechanism to normalize the stiffness of resistance vessels in response to the increase in media thickness observed during aging.
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Affiliation(s)
| | | | | | | | - Frank V. Brozovich
- Departments of Physiology and Biomedical Engineering and Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
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Kola JB, Turarova B, Csige D, Sipos Á, Varga L, Gergely B, Refai FA, Uray IP, Docsa T, Uray K. Stretch-Induced Down-Regulation of HCN2 Suppresses Contractile Activity. Molecules 2023; 28:molecules28114359. [PMID: 37298834 DOI: 10.3390/molecules28114359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/12/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
Although hyperpolarization-activated and cyclic nucleotide-gated 2 channels (HCN2) are expressed in multiple cell types in the gut, the role of HCN2 in intestinal motility is poorly understood. HCN2 is down-regulated in intestinal smooth muscle in a rodent model of ileus. Thus, the purpose of this study was to determine the effects of HCN inhibition on intestinal motility. HCN inhibition with ZD7288 or zatebradine significantly suppressed both spontaneous and agonist-induced contractile activity in the small intestine in a dose-dependent and tetrodotoxin-independent manner. HCN inhibition significantly suppressed intestinal tone but not contractile amplitude. The calcium sensitivity of contractile activity was significantly suppressed by HCN inhibition. Inflammatory mediators did not affect the suppression of intestinal contractile activity by HCN inhibition but increased stretch of the intestinal tissue partially attenuated the effects of HCN inhibition on agonist-induced intestinal contractile activity. HCN2 protein and mRNA levels in intestinal smooth muscle tissue were significantly down-regulated by increased mechanical stretch compared to unstretched tissue. Increased cyclical stretch down-regulated HCN2 protein and mRNA levels in primary human intestinal smooth muscle cells and macrophages. Overall, our results suggest that decreased HCN2 expression induced by mechanical signals, such as intestinal wall distension or edema development, may contribute to the development of ileus.
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Affiliation(s)
- Job Baffin Kola
- Department of Medical Chemistry, School of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Botagoz Turarova
- Department of Medical Chemistry, School of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Dora Csige
- Department of Medical Chemistry, School of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Ádám Sipos
- Department of Medical Chemistry, School of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Luca Varga
- Department of Medical Chemistry, School of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Bence Gergely
- Department of Medical Chemistry, School of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Farah Al Refai
- Department of Medical Chemistry, School of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Iván P Uray
- Department of Clinical Oncology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Tibor Docsa
- Department of Medical Chemistry, School of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Karen Uray
- Department of Medical Chemistry, School of Medicine, University of Debrecen, 4032 Debrecen, Hungary
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Kroetsch JT, Lidington D, Bolz SS. The emerging significance of circadian rhythmicity in microvascular resistance. Chronobiol Int 2021; 39:465-475. [PMID: 34915783 DOI: 10.1080/07420528.2021.2009505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The Earth's rotation generates environmental oscillations (e.g., in light and temperature) that have imposed unique evolutionary pressures over millions of years. Consequently, the circadian clock, a ubiquitously expressed molecular system that aligns cellular function to these environmental cues, has become an integral component of our physiology. The resulting functional rhythms optimize and economize physiological performance: perturbing these rhythms, therefore, is frequently deleterious. This perspective article focuses on circadian rhythms in resistance artery myogenic reactivity, a key mechanism governing tissue perfusion, total peripheral resistance and systemic blood pressure. Emerging evidence suggests that myogenic reactivity rhythms are locally generated in a microvascular bed-specific manner at the level of smooth muscle cells. This implies that there is a distinct interface between the molecular clock and the signalling pathways underlying myogenic reactivity in the microvascular beds of different organs. By understanding the precise nature of these molecular links, it may become possible to therapeutically manipulate microvascular tone in an organ-specific manner. This raises the prospect that interventions for vascular pathologies that are challenging to treat, such as hypertension and brain malperfusion, can be significantly improved.
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Affiliation(s)
- Jeffrey T Kroetsch
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Ontario, Canada
| | - Darcy Lidington
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Ontario, Canada
| | - Steffen-Sebastian Bolz
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Ontario, Canada.,Heart & Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research, University of Toronto, Toronto, Ontario, Canada
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Quantitative real-time measurement of endothelin-1-induced contraction in single non-activated hepatic stellate cells. PLoS One 2021; 16:e0255656. [PMID: 34343209 PMCID: PMC8330899 DOI: 10.1371/journal.pone.0255656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 07/21/2021] [Indexed: 12/13/2022] Open
Abstract
Although quiescent hepatic stellate cells (HSCs) have been suggested to regulate hepatic blood flow, there is no direct evidence that quiescent HSCs display contractile abilities. Here, we developed a new method to quantitatively measure the contraction of single isolated HSCs and evaluated whether endothelin-1 (ET-1) induced contraction of HSCs in a non-activated state. HSCs isolated from mice were seeded on collagen gel containing fluorescent beads. The beads around a single HSC were observed gravitating toward the cell upon contraction. By recording the movement of each bead by fluorescent microscopy, the real-time contraction of HSCs was quantitatively evaluated. ET-1 induced a slow contraction of non-activated HSCs, which was inhibited by the non-muscle myosin II inhibitor blebbistatin, the calmodulin inhibitor W-7, and the ETA receptor antagonist ambrisentan. ET-1-induced contraction was also largely reduced in Ca2+-free conditions, but sustained contraction still remained. The tonic contraction was further diminished by the Rho-kinase inhibitor H-1152. The mRNA expression of P/Q-type voltage-dependent Ca2+ channels (VDCC), as well as STIM and Orai, constituents of store-operated channels (SOCs), was observed in mouse non-activated HSCs. ET-1-induced contraction was not affected by amlodipine, a VDCC blocker, whereas it was partly reduced by Gd3+ and amiloride, non-selective cation channel blockers. However, neither YM-58483 nor SKF-96365, which inhibit SOCs, had any effects on the contraction. These results suggest that ET-1 leads to Ca2+-influx through cation channels other than SOCs and produces myosin II-mediated contraction of non-activated HSCs via ETA receptors, as well as via mechanisms involving Ca2+-calmodulin and Rho kinase.
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Deng JT, Bhaidani S, Sutherland C, MacDonald JA, Walsh MP. Rho-associated kinase and zipper-interacting protein kinase, but not myosin light chain kinase, are involved in the regulation of myosin phosphorylation in serum-stimulated human arterial smooth muscle cells. PLoS One 2019; 14:e0226406. [PMID: 31834925 PMCID: PMC6910671 DOI: 10.1371/journal.pone.0226406] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 11/26/2019] [Indexed: 01/09/2023] Open
Abstract
Myosin regulatory light chain (LC20) phosphorylation plays an important role in vascular smooth muscle contraction and cell migration. Ca2+/calmodulin-dependent myosin light chain kinase (MLCK) phosphorylates LC20 (its only known substrate) exclusively at S19. Rho-associated kinase (ROCK) and zipper-interacting protein kinase (ZIPK) have been implicated in the regulation of LC20 phosphorylation via direct phosphorylation of LC20 at T18 and S19 and indirectly via phosphorylation of MYPT1 (the myosin targeting subunit of myosin light chain phosphatase, MLCP) and Par-4 (prostate-apoptosis response-4). Phosphorylation of MYPT1 at T696 and T853 inhibits MLCP activity whereas phosphorylation of Par-4 at T163 disrupts its interaction with MYPT1, exposing the sites of phosphorylation in MYPT1 and leading to MLCP inhibition. To evaluate the roles of MLCK, ROCK and ZIPK in these phosphorylation events, we investigated the time courses of phosphorylation of LC20, MYPT1 and Par-4 in serum-stimulated human vascular smooth muscle cells (from coronary and umbilical arteries), and examined the effects of siRNA-mediated MLCK, ROCK and ZIPK knockdown and pharmacological inhibition on these phosphorylation events. Serum stimulation induced rapid phosphorylation of LC20 at T18 and S19, MYPT1 at T696 and T853, and Par-4 at T163, peaking within 30–120 s. MLCK knockdown or inhibition, or Ca2+ chelation with EGTA, had no effect on serum-induced LC20 phosphorylation. ROCK knockdown decreased the levels of phosphorylation of LC20 at T18 and S19, of MYPT1 at T696 and T853, and of Par-4 at T163, whereas ZIPK knockdown decreased LC20 diphosphorylation, but increased phosphorylation of MYPT1 at T696 and T853 and of Par-4 at T163. ROCK inhibition with GSK429286A reduced serum-induced phosphorylation of LC20 at T18 and S19, MYPT1 at T853 and Par-4 at T163, while ZIPK inhibition by HS38 reduced only LC20 diphosphorylation. We also demonstrated that serum stimulation induced phosphorylation (activation) of ZIPK, which was inhibited by ROCK and ZIPK down-regulation and inhibition. Finally, basal phosphorylation of LC20 in the absence of serum stimulation was unaffected by MLCK, ROCK or ZIPK knockdown or inhibition. We conclude that: (i) serum stimulation of cultured human arterial smooth muscle cells results in rapid phosphorylation of LC20, MYPT1, Par-4 and ZIPK, in contrast to the slower phosphorylation of kinases and other proteins involved in other signaling pathways (Akt, ERK1/2, p38 MAPK and HSP27), (ii) ROCK and ZIPK, but not MLCK, are involved in serum-induced phosphorylation of LC20, (iii) ROCK, but not ZIPK, directly phosphorylates MYPT1 at T853 and Par-4 at T163 in response to serum stimulation, (iv) ZIPK phosphorylation is enhanced by serum stimulation and involves phosphorylation by ROCK and autophosphorylation, and (v) basal phosphorylation of LC20 under serum-free conditions is not attributable to MLCK, ROCK or ZIPK.
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Affiliation(s)
- Jing-Ti Deng
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sabreena Bhaidani
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Cindy Sutherland
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Justin A. MacDonald
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Michael P. Walsh
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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Chen CJ, Xiao P, Chen Y, Fang R. Selenium Deficiency Affects Uterine Smooth Muscle Contraction Through Regulation of the RhoA/ROCK Signalling Pathway in Mice. Biol Trace Elem Res 2019; 192:277-286. [PMID: 30805877 DOI: 10.1007/s12011-019-01677-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 02/13/2019] [Indexed: 10/27/2022]
Abstract
Selenium (Se) is considered one of the essential micronutrients for humans and animals, and its effects on physiological functions are multifaceted. In the present study, we investigated the effects of Se deficiency on uterine smooth muscle contraction in mice by studying G protein Rho (RhoA)/Rho kinase (ROCK) signalling pathway-related molecules. The α-sma in smooth muscle tissue of mice was determined. The extracorporeal contraction curve for uterine smooth muscle in mice was determined. Both of these results indicate that Se deficiency impairs the contractile ability of uterine smooth muscle in mice. The expression of mRNA was measured by real-time quantitative PCR. The results showed that there was no significant change in mRNA expression of RhoA, ROCK, myosin light chain phosphatase (MLCP), or myosin light chain (MLC) in tissues. The protein levels were detected by Western blot. The results showed that there were no significant differences in RhoA, ROCK, MLCP, or MLC expression. However, compared with the CG, the concentration of phosphorylated MLC (P-MLC) increased in the SG and the concentration of P-MLC decreased in the DG. The activity of ROCK and MLCP was tested by liquid scintillation. The results suggest that the lack of Se may affect the regulation of MLCP by ROCK. Cellular experiments were performed to compare with results from tissues. There was no significant difference between the two models. The results indicated that Se deficiency affects uterine smooth muscle contraction by regulating the RhoA/ROCK signalling pathway. As the concentration of Se decreases, the activity of MLCP increases, which promotes the dephosphorylation of P-MLC, causing a decrease in contraction.
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Affiliation(s)
- Cheng-Jie Chen
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Peng Xiao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Yu Chen
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Rui Fang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
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7
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ROCK inhibition in models of neurodegeneration and its potential for clinical translation. Pharmacol Ther 2018; 189:1-21. [DOI: 10.1016/j.pharmthera.2018.03.008] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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8
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Lavenus S, Simard É, Besserer-Offroy É, Froehlich U, Leduc R, Grandbois M. Label-free cell signaling pathway deconvolution of angiotensin type 1 receptor reveals time-resolved G-protein activity and distinct AngII and AngIIIIV responses. Pharmacol Res 2018; 136:108-120. [PMID: 29959993 DOI: 10.1016/j.phrs.2018.06.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/18/2018] [Accepted: 06/26/2018] [Indexed: 01/14/2023]
Abstract
Angiotensin II (AngII) type 1 receptor (AT1R) is a G protein-coupled receptor known for its role in numerous physiological processes and its implication in many vascular diseases. Its functions are mediated through G protein dependent and independent signaling pathways. AT1R has several endogenous peptidic agonists, all derived from angiotensinogen, as well as several synthetic ligands known to elicit biased signaling responses. Here, surface plasmon resonance (SPR) was used as a cell-based and label-free technique to quantify, in real time, the response of HEK293 cells stably expressing the human AT1R. The goal was to take advantage of the integrative nature of this assay to identify specific signaling pathways in the features of the response profiles generated by numerous endogenous and synthetic ligands of AT1R. First, we assessed the contributions of Gq, G12/13, Gi, Gβγ, ERK1/2 and β-arrestins pathways in the cellular responses measured by SPR where Gq, G12/Rho/ROCK together with β-arrestins and ERK1/2 were found to play significant roles. More specifically, we established a major role for G12 in the early events of the AT1R-dependent response, which was followed by a robust ERK1/2 component associated to the later phase of the signal. Interestingly, endogenous AT1R ligands (AngII, AngIII and AngIV) exhibited distinct responses signatures with a significant increase of the ERK1/2-like components for both AngIII and AngIV, which points toward possibly distinct physiological roles for the later. We also tested AT1R biased ligands, all of which affected both the early and later events. Our results support SPR-based integrative cellular assays as a powerful approach to delineate the contribution of specific signaling pathways for a given cell response and reveal response differences associated with ligands with distinct pharmacological properties.
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Affiliation(s)
- Sandrine Lavenus
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Élie Simard
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Élie Besserer-Offroy
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Ulrike Froehlich
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Richard Leduc
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
| | - Michel Grandbois
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada; Institut de pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1H5N4, Canada.
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Hanson SFL, Terry MH, Moretta DT, Power GG, Wilson SM, Alam F, Ahsan F, Blood AB, Giri PC. Inhaled Fasudil Lacks Pulmonary Selectivity in Thromboxane-Induced Acute Pulmonary Hypertension in Newborn Lambs. J Cardiovasc Pharmacol Ther 2018; 23:472-480. [PMID: 29756460 DOI: 10.1177/1074248418772814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Pulmonary hypertension (PH) is a potentially deadly disease for infants and adults with few existing medical interventions and no cure. In PH, increased blood pressure in the pulmonary artery eventually leads to heart failure. Fasudil, an antagonist of Rho-kinase, causes vasodilation leading to decreased systemic artery pressure and pulmonary artery pressure (PAP). This study compared the effects of fasudil administered as either an intravenous infusion or inhaled aerosol in newborn lambs. HYPOTHESIS Inhaled aerosol delivery of fasudil will provide selective pulmonary vasodilation when compared with intravenous administration. METHODS Newborn lambs (∼11 days) were surgically instrumented and mechanically ventilated under anesthesia. A pulmonary artery catheter and ultrasonic flow probe were inserted to measure hemodynamics. Acute PH was pharmaceutically induced via continuous intravenous infusion of thromboxane. After achieving a 2- to 3-fold elevation of PAP, fasudil was administered either as intravenous infusion (2.5 mg/kg) or inhaled aerosol (100 mg of fasudil in 2 mL of saline). Changes in PAP, mean systemic arterial pressure (MABP), pulmonary vascular resistance (PVR), systemic vascular resistance (SVR), cardiac output, and heart rate were assessed. In addition, plasma concentrations of fasudil were measured. RESULTS Both routes of fasudil delivery produced significant decreases in PAP and PVR but also produced similar decreases in MABP and SVR. The Cmax for intravenous fasudil was greater than that for inhaled fasudil. CONCLUSIONS These results suggest inhaled fasudil lacks pulmonary selectivity when compared with intravenous fasudil.
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Affiliation(s)
- Shawn F L Hanson
- 1 Department of Pediatrics, Division of Neonatology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Michael H Terry
- 2 Department of Respiratory Care, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Dafne T Moretta
- 3 Division of Pulmonary and Critical Care Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Gordon G Power
- 1 Department of Pediatrics, Division of Neonatology, Loma Linda University School of Medicine, Loma Linda, CA, USA
- 4 Lawrence D. Longo Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Sean M Wilson
- 4 Lawrence D. Longo Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Farzana Alam
- 5 Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA
| | - Fakhrul Ahsan
- 5 Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA
| | - Arlin B Blood
- 1 Department of Pediatrics, Division of Neonatology, Loma Linda University School of Medicine, Loma Linda, CA, USA
- 4 Lawrence D. Longo Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Paresh C Giri
- 3 Division of Pulmonary and Critical Care Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA
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Robichaux WG, Cheng X. Intracellular cAMP Sensor EPAC: Physiology, Pathophysiology, and Therapeutics Development. Physiol Rev 2018; 98:919-1053. [PMID: 29537337 PMCID: PMC6050347 DOI: 10.1152/physrev.00025.2017] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 12/13/2022] Open
Abstract
This review focuses on one family of the known cAMP receptors, the exchange proteins directly activated by cAMP (EPACs), also known as the cAMP-regulated guanine nucleotide exchange factors (cAMP-GEFs). Although EPAC proteins are fairly new additions to the growing list of cAMP effectors, and relatively "young" in the cAMP discovery timeline, the significance of an EPAC presence in different cell systems is extraordinary. The study of EPACs has considerably expanded the diversity and adaptive nature of cAMP signaling associated with numerous physiological and pathophysiological responses. This review comprehensively covers EPAC protein functions at the molecular, cellular, physiological, and pathophysiological levels; and in turn, the applications of employing EPAC-based biosensors as detection tools for dissecting cAMP signaling and the implications for targeting EPAC proteins for therapeutic development are also discussed.
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Affiliation(s)
- William G Robichaux
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
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11
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Role of rho-kinase (ROCK) in tonic but not phasic contraction in the frog stomach smooth muscle. Life Sci 2018; 198:46-55. [PMID: 29455004 DOI: 10.1016/j.lfs.2018.02.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 02/14/2018] [Accepted: 02/15/2018] [Indexed: 01/17/2023]
Abstract
AIMS Rho/Rho-kinase (ROCK) signaling has extensively been shown to take part in mammalian smooth muscle contractions in response to diverse agents yet its role in the contraction of amphibian smooth muscle has not been investigated. Therefore, we aimed to explore any role of this pathway in the contractions of frog stomach smooth. MAIN METHODS The strips were prepared and suspended in organ baths filled with Ringer solution. Changes in the circular strips of the frog stomach muscle length were recorded isotonically with a force transducer in organ baths. KEY FINDINGS Carbachol (CCh) exerted both phasic and tonic contractions. In contrast, atropin abolished all types of contractions by CCh. The phasic contractions were suppressed by a Ca2+ channel blocker, nifedipine but not by the ROCK inhibitor, Y-27632. However, the tonic contractions were markedly attenuated by Y-27632. Selective M1 receptor blocker, pirenzepin, selective M3 receptor blocker and DAMP had no effects on CCh-elicited contractions. On the other hand, selective M2 receptor blocker, AF-DX suppressed all types of contractile activity by CCh. SIGNIFICANCE These data suggest that M2 receptor activation could mainly mediate CCh-induced phasic and tonic contractions, and ROCK seems to be involved in the CCh-induced tonic but not phasic contractions of the frog stomach smooth muscle.
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12
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Control of astrocyte morphology by Rho GTPases. Brain Res Bull 2017; 136:44-53. [PMID: 28502648 DOI: 10.1016/j.brainresbull.2017.05.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 05/05/2017] [Accepted: 05/10/2017] [Indexed: 12/15/2022]
Abstract
Astrocytes modulate and support neuronal and synapse function via numerous mechanisms that often rely on diffusion of signalling molecules, ions or metabolites through extracellular space. As a consequence, the spatial arrangement and the distance between astrocyte processes and neuronal structures are of functional importance. Likewise, changes of astrocyte structure will affect the ability of astrocytes to interact with neurons. In contrast to neurons, where rapid morphology changes are critically involved in many aspects of physiological brain function, a role of astrocyte restructuring in brain physiology is only beginning to emerge. In neurons, small GTPases of the Rho family are powerful initiators and modulators of structural changes. Less is known about the functional significance of these signalling molecules in astrocytes. Here, we review recent experimental evidence for the role of RhoA, Cdc42 and Rac1 in controlling dynamic astrocyte morphology as well as experimental tools and analytical approaches for studying astrocyte morphology changes.
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13
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A screening assay for the identification of host cell requirements and antiviral targets for hepatitis D virus infection. Antiviral Res 2017; 141:116-123. [PMID: 28223128 DOI: 10.1016/j.antiviral.2017.02.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 01/10/2023]
Abstract
Hepatitis delta virus (HDV) is a minimalistic satellite virus of hepatitis B virus (HBV). HBV/HDV co-infection, i.e. "hepatitis D", is the most severe form of viral hepatitis. No effective therapy for HDV infection is available partly due to the fact that HDV is a highly host-dependent virus devoid of any potentially drugable enzyme encoded in its small genome. In this study we present a semi-automated method to evaluate HDV infection and replication under the influence of different drugs. We utilized a Huh-7/hNTCP cell culture based system in a 96-well plate format, an automated microscope and image acquisition as well as analysis with the CellProfiler software to quantify the impact of these drugs on HDV infection. For validation, three groups of potential anti-HDV agents were evaluated: To target ribozyme activity of HDV RNA, we screened ribozyme inhibitors but only observed marked toxicity. Testing innate antiviral mediators showed that interferons alpha-2a and beta-1a had a specific inhibitory effect on HDV infection. Finally, we screened a library of 160 human kinase inhibitors covering all parts of the human kinome. Overall, only inhibitors targeting the tyrosine kinase-like group had significant average anti-HDV activity. Looking at individual substances, kenpaullone, a GSK-3β and Cdk inhibitor, had the highest selective index of 3.44. Thus, we provide a potentially useful tool to screen for substances with anti-HDV activity and novel insights into interactions between HDV replication and the human kinome.
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14
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Koziol-White CJ, Yoo EJ, Cao G, Zhang J, Papanikolaou E, Pushkarsky I, Andrews A, Himes BE, Damoiseaux RD, Liggett SB, Di Carlo D, Kurten RC, Panettieri RA. Inhibition of PI3K promotes dilation of human small airways in a rho kinase-dependent manner. Br J Pharmacol 2016; 173:2726-38. [PMID: 27352269 PMCID: PMC4995285 DOI: 10.1111/bph.13542] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 05/27/2016] [Accepted: 06/05/2016] [Indexed: 12/03/2022] Open
Abstract
Background and Purpose Asthma manifests as a heterogeneous syndrome characterized by airway obstruction, inflammation and hyperresponsiveness (AHR). Although the molecular mechanisms remain unclear, activation of specific PI3K isoforms mediate inflammation and AHR. We aimed to determine whether inhibition of PI3Kδ evokes dilation of airways and to elucidate potential mechanisms. Experimental Approach Human precision cut lung slices from non‐asthma donors and primary human airway smooth muscle (HASM) cells from both non‐asthma and asthma donors were utilized. Phosphorylation of Akt, myosin phosphatase target subunit 1 (MYPT1) and myosin light chain (MLC) were assessed in HASM cells following either PI3K inhibitor or siRNA treatment. HASM relaxation was assessed by micro‐pattern deformation. Reversal of constriction of airways was assessed following stimulation with PI3K or ROCK inhibitors. Key Results Soluble inhibitors or PI3Kδ knockdown reversed carbachol‐induced constriction of human airways, relaxed agonist‐contracted HASM and inhibited pAkt, pMYPT1 and pMLC in HASM. Similarly, inhibition of Rho kinase also dilated human PCLS airways and suppressed pMYPT1 and pMLC. Baseline pMYPT1 was significantly elevated in HASM cells derived from asthma donors in comparison with non‐asthma donors. After desensitization of the β2‐adrenoceptors, a PI3Kδ inhibitor remained an effective dilator. In the presence of IL‐13, dilation by a β agonist, but not PI3K inhibitor, was attenuated. Conclusion and Implications PI3Kδ inhibitors act as dilators of human small airways. Taken together, these findings provide alternative approaches to the clinical management of airway obstruction in asthma.
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Affiliation(s)
- Cynthia J Koziol-White
- Rutgers Institute for Translational Medicine and Science, Child Health Institute, Rutgers University, New Brunswick, NJ, USA
| | - Edwin J Yoo
- Rutgers Institute for Translational Medicine and Science, Child Health Institute, Rutgers University, New Brunswick, NJ, USA
| | - Gaoyuan Cao
- Rutgers Institute for Translational Medicine and Science, Child Health Institute, Rutgers University, New Brunswick, NJ, USA
| | - Jie Zhang
- Rutgers Institute for Translational Medicine and Science, Child Health Institute, Rutgers University, New Brunswick, NJ, USA
| | - Eleni Papanikolaou
- Rutgers Institute for Translational Medicine and Science, Child Health Institute, Rutgers University, New Brunswick, NJ, USA
| | - Ivan Pushkarsky
- Department of Bioengineering, University of California, Los Angeles, CA, USA
| | - Adam Andrews
- Department of Bioengineering, University of California, Los Angeles, CA, USA
| | - Blanca E Himes
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert D Damoiseaux
- California NanoSystems Institute, University of California, Los Angeles, CA, USA.,Department of Molecular and Medicinal Pharmacology, University of California, Los Angeles, CA, USA
| | | | - Dino Di Carlo
- Department of Bioengineering, University of California, Los Angeles, CA, USA.,California NanoSystems Institute, University of California, Los Angeles, CA, USA.,Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA, USA
| | - Richard C Kurten
- Arkansas Children's Hospital Research Institute and Department of Physiology & Biophysics, University of Arkansas Medical Sciences, Little Rock, AR, USA
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Child Health Institute, Rutgers University, New Brunswick, NJ, USA
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15
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Brozovich FV, Nicholson CJ, Degen CV, Gao YZ, Aggarwal M, Morgan KG. Mechanisms of Vascular Smooth Muscle Contraction and the Basis for Pharmacologic Treatment of Smooth Muscle Disorders. Pharmacol Rev 2016; 68:476-532. [PMID: 27037223 PMCID: PMC4819215 DOI: 10.1124/pr.115.010652] [Citation(s) in RCA: 291] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The smooth muscle cell directly drives the contraction of the vascular wall and hence regulates the size of the blood vessel lumen. We review here the current understanding of the molecular mechanisms by which agonists, therapeutics, and diseases regulate contractility of the vascular smooth muscle cell and we place this within the context of whole body function. We also discuss the implications for personalized medicine and highlight specific potential target molecules that may provide opportunities for the future development of new therapeutics to regulate vascular function.
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Affiliation(s)
- F V Brozovich
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - C J Nicholson
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - C V Degen
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - Yuan Z Gao
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - M Aggarwal
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - K G Morgan
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
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16
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Perrino BA. Calcium Sensitization Mechanisms in Gastrointestinal Smooth Muscles. J Neurogastroenterol Motil 2016; 22:213-25. [PMID: 26701920 PMCID: PMC4819859 DOI: 10.5056/jnm15186] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 12/22/2014] [Indexed: 01/05/2023] Open
Abstract
An increase in intracellular Ca2+ is the primary trigger of contraction of gastrointestinal (GI) smooth muscles. However, increasing the Ca2+ sensitivity of the myofilaments by elevating myosin light chain phosphorylation also plays an essential role. Inhibiting myosin light chain phosphatase activity with protein kinase C-potentiated phosphatase inhibitor protein-17 kDa (CPI-17) and myosin phosphatase targeting subunit 1 (MYPT1) phosphorylation is considered to be the primary mechanism underlying myofilament Ca2+ sensitization. The relative importance of Ca2+ sensitization mechanisms to the diverse patterns of GI motility is likely related to the varied functional roles of GI smooth muscles. Increases in CPI-17 and MYPT1 phosphorylation in response to agonist stimulation regulate myosin light chain phosphatase activity in phasic, tonic, and sphincteric GI smooth muscles. Recent evidence suggests that MYPT1 phosphorylation may also contribute to force generation by reorganization of the actin cytoskeleton. The mechanisms responsible for maintaining constitutive CPI-17 and MYPT1 phosphorylation in GI smooth muscles are still largely unknown. The characteristics of the cell-types comprising the neuroeffector junction lead to fundamental differences between the effects of exogenous agonists and endogenous neurotransmitters on Ca2+ sensitization mechanisms. The contribution of various cell-types within the tunica muscularis to the motor responses of GI organs to neurotransmission must be considered when determining the mechanisms by which Ca2+ sensitization pathways are activated. The signaling pathways regulating Ca2+ sensitization may provide novel therapeutic strategies for controlling GI motility. This article will provide an overview of the current understanding of the biochemical basis for the regulation of Ca2+ sensitization, while also discussing the functional importance to different smooth muscles of the GI tract.
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Affiliation(s)
- Brian A Perrino
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, USA
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17
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Erectile dysfunction in heart failure rats is associated with increased neurogenic contractions in cavernous tissue and internal pudendal artery. Life Sci 2016; 145:9-18. [DOI: 10.1016/j.lfs.2015.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/24/2015] [Accepted: 12/02/2015] [Indexed: 10/22/2022]
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18
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Defert O, Boland S. Kinase profiling in early stage drug discovery: sorting things out. DRUG DISCOVERY TODAY. TECHNOLOGIES 2015; 18:52-61. [PMID: 26723893 DOI: 10.1016/j.ddtec.2015.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 10/07/2015] [Indexed: 01/07/2023]
Abstract
Protein kinases represent one of the largest superfamilies of drugable targets and a major research area for both the pharmaceutical industry and academic groups. This has resulted in the emergence of numerous screening technologies and services dedicated to kinase profiling. In spite of this plentiful offering, the field is not without its own pitfalls, as the profusion of reported conditions and data can ultimately complicate interpretation of project results. Here, we discuss how kinase profiling was used in our early stage drug discovery efforts, from the perspective of a smaller biotech relying largely on assay outsourcing.
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Affiliation(s)
- Olivier Defert
- Amakem Therapeutics N.V. Agoralaan Abis, 3590 Diepenbeek, Belgium.
| | - Sandro Boland
- Amakem Therapeutics N.V. Agoralaan Abis, 3590 Diepenbeek, Belgium
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19
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Deng JT, Wang XL, Chen YX, O’Brien ER, Gui Y, Walsh MP. The effects of knockdown of rho-associated kinase 1 and zipper-interacting protein kinase on gene expression and function in cultured human arterial smooth muscle cells. PLoS One 2015; 10:e0116969. [PMID: 25723491 PMCID: PMC4344299 DOI: 10.1371/journal.pone.0116969] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 12/17/2014] [Indexed: 12/16/2022] Open
Abstract
Rho-associated kinase (ROCK) and zipper-interacting protein kinase (ZIPK) have been implicated in diverse physiological functions. ROCK1 phosphorylates and activates ZIPK suggesting that at least some of these physiological functions may require both enzymes. To test the hypothesis that sequential activation of ROCK1 and ZIPK is commonly involved in regulatory pathways, we utilized siRNA to knock down ROCK1 and ZIPK in cultured human arterial smooth muscle cells (SMC). Microarray analysis using a whole-transcript expression chip identified changes in gene expression induced by ROCK1 and ZIPK knockdown. ROCK1 knockdown affected the expression of 553 genes, while ZIPK knockdown affected the expression of 390 genes. A high incidence of regulation of transcription regulator genes was observed in both knockdowns. Other affected groups included transporters, kinases, peptidases, transmembrane and G protein-coupled receptors, growth factors, phosphatases and ion channels. Only 76 differentially expressed genes were common to ROCK1 and ZIPK knockdown. Ingenuity Pathway Analysis identified five pathways shared between the two knockdowns. We focused on cytokine signaling pathways since ROCK1 knockdown up-regulated 5 and down-regulated 4 cytokine genes, in contrast to ZIPK knockdown, which affected the expression of only two cytokine genes (both down-regulated). IL-6 gene expression and secretion of IL-6 protein were up-regulated by ROCK1 knockdown, whereas ZIPK knockdown reduced IL-6 mRNA expression and IL-6 protein secretion and increased ROCK1 protein expression, suggesting that ROCK1 may inhibit IL-6 secretion. IL-1β mRNA and protein levels were increased in response to ROCK1 knockdown. Differences in the effects of ROCK1 and ZIPK knockdown on cell cycle regulatory genes suggested that ROCK1 and ZIPK regulate the cell cycle by different mechanisms. ROCK1, but not ZIPK knockdown reduced the viability and inhibited proliferation of vascular SMC. We conclude that ROCK1 and ZIPK have diverse, but predominantly distinct regulatory functions in vascular SMC and that ROCK1-mediated activation of ZIPK is not involved in most of these functions.
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Affiliation(s)
- Jing-Ti Deng
- Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, University of Calgary, Alberta, Canada
| | - Xiu-Ling Wang
- Southern Alberta Cancer Research Institute Microarray and Genomics Facility, University of Calgary, Alberta, Canada
| | - Yong-Xiang Chen
- Division of Cardiology, Libin Cardiovascular Institute of Alberta, University of Calgary, Alberta, Canada
| | - Edward R. O’Brien
- Division of Cardiology, Libin Cardiovascular Institute of Alberta, University of Calgary, Alberta, Canada
| | - Yu Gui
- Department of Physiology and Pharmacology, University of Calgary, Alberta, Canada
| | - Michael P. Walsh
- Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, University of Calgary, Alberta, Canada
- Hotchkiss Brain Institute and Libin Cardiovascular Institute of Alberta, University of Calgary, Alberta, Canada
- * E-mail:
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20
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Lan B, Deng L, Donovan GM, Chin LYM, Syyong HT, Wang L, Zhang J, Pascoe CD, Norris BA, Liu JCY, Swyngedouw NE, Banaem SM, Paré PD, Seow CY. Force maintenance and myosin filament assembly regulated by Rho-kinase in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2014; 308:L1-10. [PMID: 25305246 DOI: 10.1152/ajplung.00222.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Smooth muscle contraction can be divided into two phases: the initial contraction determines the amount of developed force and the second phase determines how well the force is maintained. The initial phase is primarily due to activation of actomyosin interaction and is relatively well understood, whereas the second phase remains poorly understood. Force maintenance in the sustained phase can be disrupted by strains applied to the muscle; the strain causes actomyosin cross-bridges to detach and also the cytoskeletal structure to disassemble in a process known as fluidization, for which the underlying mechanism is largely unknown. In the present study we investigated the ability of airway smooth muscle to maintain force after the initial phase of contraction. Specifically, we examined the roles of Rho-kinase and protein kinase C (PKC) in force maintenance. We found that for the same degree of initial force inhibition, Rho-kinase substantially reduced the muscle's ability to sustain force under static conditions, whereas inhibition of PKC had a minimal effect on sustaining force. Under oscillatory strain, Rho-kinase inhibition caused further decline in force, but again, PKC inhibition had a minimal effect. We also found that Rho-kinase inhibition led to a decrease in the myosin filament mass in the muscle cells, suggesting that one of the functions of Rho-kinase is to stabilize myosin filaments. The results also suggest that dissolution of myosin filaments may be one of the mechanisms underlying the phenomenon of fluidization. These findings can shed light on the mechanism underlying deep inspiration induced bronchodilation.
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Affiliation(s)
- Bo Lan
- Bioengineering College, Chongqing University, Chongqing, China; Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, China; and Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Linhong Deng
- Bioengineering College, Chongqing University, Chongqing, China; Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, China; and
| | - Graham M Donovan
- Department of Mathematics, University of Auckland, Auckland, New Zealand
| | - Leslie Y M Chin
- Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Harley T Syyong
- Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Lu Wang
- Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Jenny Zhang
- Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Christopher D Pascoe
- Department of Medicine, University of British Columbia, Vancouver, Canada; Vancouver, Canada; Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Brandon A Norris
- Department of Medicine, University of British Columbia, Vancouver, Canada; Vancouver, Canada; Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Jeffrey C-Y Liu
- Department of Medicine, University of British Columbia, Vancouver, Canada; Vancouver, Canada; Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Nicholas E Swyngedouw
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada; Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Saleha M Banaem
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada; Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Peter D Paré
- Department of Medicine, University of British Columbia, Vancouver, Canada; Vancouver, Canada; Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
| | - Chun Y Seow
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada; Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, Canada
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21
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Lima VV, Lobato NS, Filgueira FP, Webb RC, Tostes RC, Giachini FR. Vascular O-GlcNAcylation augments reactivity to constrictor stimuli by prolonging phosphorylated levels of the myosin light chain. ACTA ACUST UNITED AC 2014; 47:826-33. [PMID: 25140811 PMCID: PMC4181217 DOI: 10.1590/1414-431x20144001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/09/2014] [Indexed: 01/31/2024]
Abstract
O-GlcNAcylation is a modification that alters the function of numerous proteins. We hypothesized that augmented O-GlcNAcylation levels enhance myosin light chain kinase (MLCK) and reduce myosin light chain phosphatase (MLCP) activity, leading to increased vascular contractile responsiveness. The vascular responses were measured by isometric force displacement. Thoracic aorta and vascular smooth muscle cells (VSMCs) from rats were incubated with vehicle or with PugNAc, which increases O-GlcNAcylation. In addition, we determined whether proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation. PugNAc enhanced phenylephrine (PE) responses in rat aortas (maximal effect, 14.2 ± 2 vs 7.9 ± 1 mN for vehicle, n=7). Treatment with an MLCP inhibitor (calyculin A) augmented vascular responses to PE (13.4 ± 2 mN) and abolished the differences in PE-response between the groups. The effect of PugNAc was not observed when vessels were preincubated with ML-9, an MLCK inhibitor (7.3 ± 2 vs 7.5 ± 2 mN for vehicle, n=5). Furthermore, our data showed that differences in the PE-induced contractile response between the groups were abolished by the activator of AMP-activated protein kinase (AICAR; 6.1 ± 2 vs 7.4 ± 2 mN for vehicle, n=5). PugNAc increased phosphorylation of myosin phosphatase target subunit 1 (MYPT-1) and protein kinase C-potentiated inhibitor protein of 17 kDa (CPI-17), which are involved in RhoA/Rho-kinase-mediated inhibition of myosin phosphatase activity. PugNAc incubation produced a time-dependent increase in vascular phosphorylation of myosin light chain and decreased phosphorylation levels of AMP-activated protein kinase, which decreased the affinity of MLCK for Ca(2+)/calmodulin. Our data suggest that proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation, favoring vascular contraction.
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Affiliation(s)
- V V Lima
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso, Barra do Garças, MT, Brasil
| | - N S Lobato
- Curso de Medicina, Setor de Fisiologia Humana, Universidade Federal de Goiás, Jataí, GO, Brasil
| | - F P Filgueira
- Curso de Medicina, Setor de Fisiologia Humana, Universidade Federal de Goiás, Jataí, GO, Brasil
| | - R C Webb
- Department of Physiology, Georgia Regents University, Augusta, GA, USA
| | - R C Tostes
- Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - F R Giachini
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso, Barra do Garças, MT, Brasil
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22
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Julian L, Olson MF. Rho-associated coiled-coil containing kinases (ROCK): structure, regulation, and functions. Small GTPases 2014; 5:e29846. [PMID: 25010901 PMCID: PMC4114931 DOI: 10.4161/sgtp.29846] [Citation(s) in RCA: 356] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 07/02/2014] [Accepted: 07/07/2014] [Indexed: 12/29/2022] Open
Abstract
Rho-associated coiled-coil containing kinases (ROCK) were originally identified as effectors of the RhoA small GTPase. (1)(-) (5) They belong to the AGC family of serine/threonine kinases (6) and play vital roles in facilitating actomyosin cytoskeleton contractility downstream of RhoA and RhoC activation. Since their discovery, ROCK kinases have been extensively studied, unveiling their manifold functions in processes including cell contraction, migration, apoptosis, survival, and proliferation. Two mammalian ROCK homologs have been identified, ROCK1 (also called ROCK I, ROKβ, Rho-kinase β, or p160ROCK) and ROCK2 (also known as ROCK II, ROKα, or Rho kinase), hereafter collectively referred to as ROCK. In this review, we will focus on the structure, regulation, and functions of ROCK.
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Affiliation(s)
- Linda Julian
- Beatson Institute for Cancer Research; Glasgow, UK
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23
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Resveratrol prevents AngII-induced hypertension via AMPK activation and RhoA/ROCK suppression in mice. Hypertens Res 2014; 37:803-10. [PMID: 24965170 DOI: 10.1038/hr.2014.90] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 02/09/2014] [Accepted: 02/13/2014] [Indexed: 12/20/2022]
Abstract
The purpose of this study was to determine the effects of resveratrol (RSV) and the molecular mechanisms by which it regulates vascular smooth muscle contraction and blood pressure in mice. In cultured human vascular smooth muscle cells (VSMCs), we found that the activation of AMP-activated protein kinase (AMPK) by RSV inhibited angiotensin II (AngII)-induced phosphorylation of myosin phosphatase-targeting subunit 1 (MYPT1) and myosin light chain (MLC). Inversely, AMPK inhibition with RNA interference and compound C, an AMPK inhibitor, abolished the inhibitory effect of RSV on AngII-induced MYPT1 and MLC phosphorylation. Thiazovivin, a Rho-associated kinase (ROCK) inhibitor, reversed AngII-induced MYPT1 and MLC phosphorylation, suggesting that ROCK functions as an upstream kinase for MYPT1/MLC. RSV reversed AngII-induced Ras homolog gene family member A (RhoA) and ROCK activity, whereas AMPK inhibition via pharmacological or genetic means abolished this effect. In addition, gene silencing of p190-guanosine triphosphatase-activating protein blocked the effects of RSV-induced AMPK activation on MLC, MYPT1 and RhoA in VSMCs. Ex vivo analyses demonstrated that AngII-induced aorta contractions were dramatically inhibited by RSV, and this effect was abolished by AMPK inhibition. Finally, daily chronic administration of RSVl alleviated hypertension in the experimental model of AngII-induced hypertensive mice, and these effects were accompanied by the activation of AMPK, significantly decreased RhoA activity and phosphorylation levels of MYPT1 and MLC in AngII-treated murine aortic VSMCs. More importantly, administration of compound C significantly abolished the effects of RSV. In conclusion, AMPK suppression of the p190-GAP-dependent RhoA/ROCK/MYPT1/MLC pathway contributes to the hypotensive effect of RSV in AngII-treated mice.
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24
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Pedraza CE, Taylor C, Pereira A, Seng M, Tham CS, Izrael M, Webb M. Induction of oligodendrocyte differentiation and in vitro myelination by inhibition of rho-associated kinase. ASN Neuro 2014; 6:6/4/1759091414538134. [PMID: 25289646 PMCID: PMC4189421 DOI: 10.1177/1759091414538134] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In inflammatory demyelinating diseases such as multiple sclerosis (MS), myelin
degradation results in loss of axonal function and eventual axonal degeneration.
Differentiation of resident oligodendrocyte precursor cells (OPCs) leading to
remyelination of denuded axons occurs regularly in early stages of MS but halts as
the pathology transitions into progressive MS. Pharmacological potentiation of
endogenous OPC maturation and remyelination is now recognized as a promising
therapeutic approach for MS. In this study, we analyzed the effects of modulating the
Rho-A/Rho-associated kinase (ROCK) signaling pathway, by the use of selective
inhibitors of ROCK, on the transformation of OPCs into mature, myelinating
oligodendrocytes. Here we demonstrate, with the use of cellular cultures from rodent
and human origin, that ROCK inhibition in OPCs results in a significant generation of
branches and cell processes in early differentiation stages, followed by accelerated
production of myelin protein as an indication of advanced maturation. Furthermore,
inhibition of ROCK enhanced myelin formation in cocultures of human OPCs and neurons
and remyelination in rat cerebellar tissue explants previously demyelinated with
lysolecithin. Our findings indicate that by direct inhibition of this signaling
molecule, the OPC differentiation program is activated resulting in morphological and
functional cell maturation, myelin formation, and regeneration. Altogether, we show
evidence of modulation of the Rho-A/ROCK signaling pathway as a viable target for the
induction of remyelination in demyelinating pathologies.
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Affiliation(s)
- Carlos E Pedraza
- EMD Serono Research & Development Institute, Inc., Billerica, MA, USA
| | | | - Albertina Pereira
- EMD Serono Research & Development Institute, Inc., Billerica, MA, USA
| | - Michelle Seng
- EMD Serono Research & Development Institute, Inc., Billerica, MA, USA
| | - Chui-Se Tham
- EMD Serono Research & Development Institute, Inc., Billerica, MA, USA
| | | | - Michael Webb
- EMD Serono Research & Development Institute, Inc., Billerica, MA, USA
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Tiftik RN, Başkurt OK, Kul S, Büyükafşar K. The functional significance of the rho/rho-kinase pathway in human erythrocytes. Turk J Haematol 2014; 31:168-74. [PMID: 25035675 PMCID: PMC4102045 DOI: 10.4274/tjh.2013.0115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 07/19/2013] [Indexed: 01/16/2023] Open
Abstract
Objective: Erythrocyte deformability, which can be influenced by various intracellular signaling mechanisms, such as nitric oxide, cAMP, cGMP, and protein kinases, is the most important physiological factor providing the blood flow in microcirculation. However, the functional significance of the Rho/Rho-kinase pathway, which contributes cell shape changes and the reorganization of the actin cytoskeleton, has yet to be explored in erythrocytes. Therefore, we examined the influence of several activators and inhibitors of Rho/Rho-kinase signaling on human erythrocyte deformability. Materials and Methods: RhoA and ROCK-2 proteins were studied by western blotting. Influences of 2 Rho-kinase inhibitors, fasudil and Y-27632 (both 10-7 to 10-4 M), on erythrocyte deformability was determined by ektacytometer at various shear stresses (0-30 Pa) in the presence or absence of a known Rho activator, lysophosphatidic acid (LPA, 10-5 to 5x10-5 M, 1-15 min). Results: LPA incubation reduced deformability with concomitant RhoA-GTP inhibition. Y-27632 and fasudil also decreased deformability, but had no effect on LPA-induced reduction of deformability. Rho inhibitor C3 had no effect on RhoA activation. Reduction in RhoA activation was induced by sub-hemolytic mechanical stress. Conclusion: Our findings may indicate that the Rho/Rho-kinase pathway could contribute to the regulation of deformability of human erythrocytes.
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Affiliation(s)
- R Nalan Tiftik
- Mersin University Faculty of Medicine, Department of Pharmacology, Mersin, Turkey
| | | | - Seval Kul
- Gaziantep University Faculty of Medicine, Department of Biostatistics, Gaziantep, Turkey
| | - Kansu Büyükafşar
- Mersin University Faculty of Medicine, Department of Pharmacology, Mersin, Turkey
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Koslov DS, Andersson KE. Physiological and pharmacological aspects of the vas deferens-an update. Front Pharmacol 2013; 4:101. [PMID: 23986701 PMCID: PMC3749770 DOI: 10.3389/fphar.2013.00101] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 07/29/2013] [Indexed: 12/22/2022] Open
Abstract
The vas deferens, a muscular conduit conveying spermatozoa from the epididymis to the urethra, has been used as a model tissue for smooth muscle pharmacological and physiological advancements. Many drugs, notably α-adrenergic antagonists, have effects on contractility and thus normal ejaculation, incurring significant side effects for patients that may interfere with compliance. A more thorough understanding of the innervation and neurotransmitter pharmacology of the vas has indicated that this is a highly complex structure and a model for co-transmission at the synapse. Recent models have shown clinical scenarios that alter the vas contraction. This review covers structure, receptors, neurotransmitters, smooth muscle physiology, and clinical implications of the vas deferens.
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Affiliation(s)
- David S Koslov
- Wake Forest Baptist Medical Center, Medical Center Boulevard Winston-Salem, NC, USA
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Schofield AV, Bernard O. Rho-associated coiled-coil kinase (ROCK) signaling and disease. Crit Rev Biochem Mol Biol 2013; 48:301-16. [PMID: 23601011 DOI: 10.3109/10409238.2013.786671] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The small Rho GTPase family of proteins, encompassing the three major G-protein classes Rho, Rac and cell division control protein 42, are key mitogenic signaling molecules that regulate multiple cancer-associated cellular phenotypes including cell proliferation and motility. These proteins are known for their role in the regulation of actin cytoskeletal dynamics, which is achieved through modulating the activity of their downstream effector molecules. The Rho-associated coiled-coil kinase 1 and 2 (ROCK1 and ROCK2) proteins were the first discovered Rho effectors that were primarily established as players in RhoA-mediated stress fiber formation and focal adhesion assembly. It has since been discovered that the ROCK kinases actively phosphorylate a large cohort of actin-binding proteins and intermediate filament proteins to modulate their functions. It is well established that global cellular morphology, as modulated by the three cytoskeletal networks: actin filaments, intermediate filaments and microtubules, is regulated by a variety of accessory proteins whose activities are dependent on their phosphorylation by the Rho-kinases. As a consequence, they regulate many key cellular functions associated with malignancy, including cell proliferation, motility and viability. In this current review, we focus on the role of the ROCK-signaling pathways in disease including cancer.
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Affiliation(s)
- Alice V Schofield
- St Vincent's Institute of Medical Research, Cytoskeleton and Cancer Unit and Department of Medicine, St Vincent's Hospital, University of Melbourne, Victoria 3065, Australia
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Lack of transient receptor potential vanilloid 1 channel modulates the development of neurogenic bladder dysfunction induced by cross-sensitization in afferent pathways. J Neuroinflammation 2013; 10:3. [PMID: 23305398 PMCID: PMC3556132 DOI: 10.1186/1742-2094-10-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 12/21/2012] [Indexed: 12/30/2022] Open
Abstract
Background Bladder pain of unknown etiology has been associated with co-morbid conditions and functional abnormalities in neighboring pelvic organs. Mechanisms underlying pain co-morbidities include cross-sensitization, which occurs predominantly via convergent neural pathways connecting distinct pelvic organs. Our previous results showed that colonic inflammation caused detrusor instability via activation of transient receptor potential vanilloid 1 (TRPV1) signaling pathways, therefore, we aimed to determine whether neurogenic bladder dysfunction can develop in the absence of TRPV1 receptors. Methods Adult male C57BL/6 wild-type (WT) and TRPV1−/− (knockout) mice were used in this study. Colonic inflammation was induced by intracolonic trinitrobenzene sulfonic acid (TNBS). The effects of transient colitis on abdominal sensitivity and function of the urinary bladder were evaluated by cystometry, contractility and relaxation of detrusor smooth muscle (DSM) in vitro to various stimuli, gene and protein expression of voltage-gated sodium channels in bladder sensory neurons, and pelvic responses to mechanical stimulation. Results Knockout of TRPV1 gene did not eliminate the development of cross-sensitization between the colon and urinary bladder. However, TRPV1−/− mice had prolonged intermicturition interval and increased number of non-voiding contractions at baseline followed by reduced urodynamic responses during active colitis. Contractility of DSM was up-regulated in response to KCl in TRPV1−/− mice with inflamed colon. Application of Rho-kinase inhibitor caused relaxation of DSM in WT but not in TRPV1−/− mice during colonic inflammation. TRPV1−/− mice demonstrated blunted effects of TNBS-induced colitis on expression and function of voltage-gated sodium channels in bladder sensory neurons, and delayed development of abdominal hypersensitivity upon colon-bladder cross-talk in genetically modified animals. Conclusions The lack of TRPV1 receptors does not eliminate the development of cross-sensitization in the pelvis. However, the function of the urinary bladder significantly differs between WT and TRPV−/− mice especially upon development of colon-bladder cross-sensitization induced by transient colitis. Our results suggest that TRPV1 pathways may participate in the development of chronic pelvic pain co-morbidities in humans.
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Richerioux N, Blondeau C, Wiedemann A, Rémy S, Vautherot JF, Denesvre C. Rho-ROCK and Rac-PAK signaling pathways have opposing effects on the cell-to-cell spread of Marek's Disease Virus. PLoS One 2012; 7:e44072. [PMID: 22952878 PMCID: PMC3428312 DOI: 10.1371/journal.pone.0044072] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 07/31/2012] [Indexed: 01/11/2023] Open
Abstract
Marek's Disease Virus (MDV) is an avian alpha-herpesvirus that only spreads from cell-to-cell in cell culture. While its cell-to-cell spread has been shown to be dependent on actin filament dynamics, the mechanisms regulating this spread remain largely unknown. Using a recombinant BAC20 virus expressing an EGFPVP22 tegument protein, we found that the actin cytoskeleton arrangements and cell-cell contacts differ in the center and periphery of MDV infection plaques, with cells in the latter areas showing stress fibers and rare cellular projections. Using specific inhibitors and activators, we determined that Rho-ROCK pathway, known to regulate stress fiber formation, and Rac-PAK, known to promote lamellipodia formation and destabilize stress fibers, had strong contrasting effects on MDV cell-to-cell spread in primary chicken embryo skin cells (CESCs). Inhibition of Rho and its ROCKs effectors led to reduced plaque sizes whereas inhibition of Rac or its group I-PAKs effectors had the adverse effect. Importantly, we observed that the shape of MDV plaques is related to the semi-ordered arrangement of the elongated cells, at the monolayer level in the vicinity of the plaques. Inhibition of Rho-ROCK signaling also resulted in a perturbation of the cell arrangement and a rounding of plaques. These opposing effects of Rho and Rac pathways in MDV cell-to-cell spread were validated for two parental MDV recombinant viruses with different ex vivo spread efficiencies. Finally, we demonstrated that Rho/Rac pathways have opposing effects on the accumulation of N-cadherin at cell-cell contact regions between CESCs, and defined these contacts as adherens junctions. Considering the importance of adherens junctions in HSV-1 cell-to-cell spread in some cell types, this result makes of adherens junctions maintenance one potential and attractive hypothesis to explain the Rho/Rac effects on MDV cell-to-cell spread. Our study provides the first evidence that MDV cell-to-cell spread is regulated by Rho/Rac signaling.
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Affiliation(s)
- Nicolas Richerioux
- INRA, UMR1282, Infectious Diseases and Public Health, ISP, BIOVA team, Nouzilly, France
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Zieba BJ, Artamonov MV, Jin L, Momotani K, Ho R, Franke AS, Neppl RL, Stevenson AS, Khromov AS, Chrzanowska-Wodnicka M, Somlyo AV. The cAMP-responsive Rap1 guanine nucleotide exchange factor, Epac, induces smooth muscle relaxation by down-regulation of RhoA activity. J Biol Chem 2011; 286:16681-92. [PMID: 21454546 PMCID: PMC3089510 DOI: 10.1074/jbc.m110.205062] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 03/11/2011] [Indexed: 11/06/2022] Open
Abstract
Agonist activation of the small GTPase, RhoA, and its effector Rho kinase leads to down-regulation of smooth muscle (SM) myosin light chain phosphatase activity, an increase in myosin light chain (RLC(20)) phosphorylation and force. Cyclic nucleotides can reverse this process. We report a new mechanism of cAMP-mediated relaxation through Epac, a GTP exchange factor for the small GTPase Rap1 resulting in an increase in Rap1 activity and suppression of RhoA activity. An Epac-selective cAMP analog, 8-pCPT-2'-O-Me-cAMP ("007"), significantly reduced agonist-induced contractile force, RLC(20), and myosin light chain phosphatase phosphorylation in both intact and permeabilized vascular, gut, and airway SMs independently of PKA and PKG. The vasodilator PGI(2) analog, cicaprost, increased Rap1 activity and decreased RhoA activity in intact SMs. Forskolin, phosphodiesterase inhibitor isobutylmethylxanthine, and isoproterenol also significantly increased Rap1-GTP in rat aortic SM cells. The PKA inhibitor H89 was without effect on the 007-induced increase in Rap1-GTP. Lysophosphatidic acid-induced RhoA activity was reduced by treatment with 007 in WT but not Rap1B null fibroblasts, consistent with Epac signaling through Rap1B to down-regulate RhoA activity. Isoproterenol-induced increase in Rap1 activity was inhibited by silencing Epac1 in rat aortic SM cells. Evidence is presented that cooperative cAMP activation of PKA and Epac contribute to relaxation of SM. Our findings demonstrate a cAMP-mediated signaling mechanism whereby activation of Epac results in a PKA-independent, Rap1-dependent Ca(2+) desensitization of force in SM through down-regulation of RhoA activity. Cyclic AMP inhibition of RhoA is mediated through activation of both Epac and PKA.
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Affiliation(s)
- Bartosz J. Zieba
- From the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908
- the Department of Cell Biochemistry, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Mykhaylo V. Artamonov
- From the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908
| | - Li Jin
- From the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908
| | - Ko Momotani
- From the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908
| | - Ruoya Ho
- From the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908
| | - Aaron S. Franke
- From the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908
| | - Ronald L. Neppl
- the Department of Cardiology, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts 02115, and
| | - Andra S. Stevenson
- From the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908
| | - Alexander S. Khromov
- From the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908
| | | | - Avril V. Somlyo
- From the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908
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Wang S, Liang B, Viollet B, Zou MH. Inhibition of the AMP-activated protein kinase-α2 accentuates agonist-induced vascular smooth muscle contraction and high blood pressure in mice. Hypertension 2011; 57:1010-7. [PMID: 21464390 DOI: 10.1161/hypertensionaha.110.168906] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The aim of the present study was to determine the effects and molecular mechanisms by which AMP-activated protein kinase (AMPK) regulates smooth muscle contraction and blood pressure in mice. In cultured human vascular smooth muscle cells, we observed that activation of AMPK by 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside inhibited agonist-induced phosphorylation of myosin light chain (MLC) and myosin phosphatase targeting subunit 1 (MYPT1). Conversely, AMPK inhibition with pharmacological or genetic means potentiated agonist-induced the phosphorylation of MLC and MYPT1, whereas it inhibited both Ras homolog gene family member A and Rho-associated kinase activity. In addition, AMPK activation or Rho-associated kinase inhibition with Y27632 abolished agonist-induced phosphorylation of MLC and MYPT1. Gene silencing of p190-guanosine triphosphatase-activating protein abolished the effects of AMPK activation on MLC, MYPT1, and Ras homolog gene family member A in human smooth muscle cells. Ex vivo analyses revealed that agonist-induced contractions of the mesenteric artery and aortas were stronger in both AMPKα1(-/-) and AMPKα2(-/-) knockout mice than in wild-type mice. Inhibition of Rho-associated kinase with Y27632 normalized agonist-induced contractions of AMPKα1(-/-) and AMPKα2(-/-) vessels. AMPKα2(-/-) mice had higher blood pressure along with decreased serine phosphorylation of p190-guanosine triphosphatase-activating protein. Finally, inhibition of the Ras homolog gene family member A/Rho-associated kinase pathway with Y27632, which suppressed MYPT1 and MLC phosphorylation, lowered blood pressure in AMPKα2(-/-) mice. In conclusion, AMPK decreases vascular smooth muscle cell contractility by inhibiting p190-GTP-activating protein-dependent Ras homolog gene family member A activation, indicating that AMPK may be a new therapeutic target in lowering high blood pressure.
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Affiliation(s)
- Shuangxi Wang
- Division of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, BSEB 325, 941 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
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Walsh MP, Thornbury K, Cole WC, Sergeant G, Hollywood M, McHale N. Rho-associated kinase plays a role in rabbit urethral smooth muscle contraction, but not via enhanced myosin light chain phosphorylation. Am J Physiol Renal Physiol 2010; 300:F73-85. [PMID: 20861082 DOI: 10.1152/ajprenal.00011.2010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The involvement of Rho-associated kinase (ROK) in activation of rabbit urethral smooth muscle contraction was investigated by examining the effects of two structurally distinct inhibitors of ROK, Y27632 and H1152, on the contractile response to electric field stimulation, membrane depolarization with KCl, and α1-adrenoceptor stimulation with phenylephrine. Both compounds inhibited contractions elicited by all three stimuli. The protein kinase C inhibitor GF109203X, on the other hand, had no effect. Urethral smooth muscle strips were analyzed for phosphorylation of three potential direct or indirect substrates of ROK: 1) myosin regulatory light chains (LC20) at S19, 2) the myosin-targeting subunit of myosin light chain phosphatase (MYPT1) at T697 and T855, and 3) cofilin at S3. The following results were obtained: 1) under resting tension, LC20 was phosphorylated to 0.65±0.02 mol Pi/mol LC20 (n=21) at S19; 2) LC20 phosphorylation did not change in response to KCl or phenylephrine; 3) ROK inhibition had no effect on LC20 phosphorylation in the absence or presence of contractile stimuli; 4) under resting conditions, MYPT1 was partially phosphorylated at T697 and T855 and cofilin at S3; 5) phosphorylation of MYPT1 and cofilin was unaffected by KCl or phenylephrine; and 6) KCl- and phenylephrine-induced contraction-relaxation cycles did not correlate with actin polymerization-depolymerization. We conclude that ROK plays an important role in urethral smooth muscle contraction, but not via inhibition of MLCP or polymerization of actin.
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Affiliation(s)
- Michael P Walsh
- Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
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Xie LN, Zeng DY, Zhang HS, Sun DM, Pang XF, Guan QG. Effect of tongxinluo on vasoconstriction induced by the chronic injury of the adventitia in the rat carotid artery. JOURNAL OF ETHNOPHARMACOLOGY 2010; 131:300-305. [PMID: 20600751 DOI: 10.1016/j.jep.2010.06.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Revised: 06/19/2010] [Accepted: 06/22/2010] [Indexed: 05/29/2023]
Abstract
OBJECTIVE Tongxinluo (TXL) is a traditional Chinese medicine that is developed on the meridian theory of traditional Chinese medicine, with the function of alleviating the angina. The present study was undertaken to explore the molecular mechanism of TXL in treating the pectoris angina through observing the effectiveness of TXL superfine powder on the vasoconstriction and the activation of RhoA/Rho-kinase pathway induced by the injury of the adventitia. METHODS 36 male Wistar Kyoto rats were assigned to 3 treatments (n=12): vehicle, TXL (400 mg kg(-1) day(-1)) and fasudil (15 mg kg(-1) day(-1)). After 1 week of treatment, adventitia injury was induced by positioning a silicone collar around the right carotid artery for 1 week. Blood flow and vascular reactivity to serotonin were determined 1 week after injurying, the both sides of carotids were harvested for morphometry, Western blotting analysis and RT-PCR analysis. RESULTS Adventitia injury leaded to histological changes of vasoconstriction with the lumen cross-sectional area of 44.7% (p<0.001) decreasing and the media diameter of 62.31% (p<0.001) increasing, accompanying by the reduction of the blood flow and the increase of vascular reactivity sensitivity to serotonin. Treatment with both TXL superfine powder and fasudil can prevent the development of vasoconstriction, improve the carotid blood flow and normalize the vascular hypersensitivity to serotonin. Adventitia injuring of the rat carotid increased the expression of Rho-kinase mRNA and p-MYPT1(Thr696) protein by 1.78-fold (p<0.05) and >2-fold respectively (p<0.05). TXL reduced the expression of Rho-kinase mRNA and p-MYPT1(Thr696) protein by 54.2% (p<0.05) and 57.1% (p<0.05) respectively in collared arteries. Fasudil restrained the p-MYPT1(Thr696) protein expression by 63.8% (p<0.05) in collared arteries, did not affect the collar-induced the increase of Rho-kinase mRNA expression (p>0.05). CONCLUSIONS Treatment with TXL, similar to that with fasudil, can effectively prevent collar-induced vasoconstriction and vascular hyperreactivity to serotonin through inhibiting the RhoA/Rho-kinase pathway.
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Affiliation(s)
- Lian Na Xie
- Cardiology Department, The First Affiliated Hospital of China Medical University, Heping District, Shenyang, China
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Mufti RE, Brett SE, Tran CHT, Abd El-Rahman R, Anfinogenova Y, El-Yazbi A, Cole WC, Jones PP, Chen SRW, Welsh DG. Intravascular pressure augments cerebral arterial constriction by inducing voltage-insensitive Ca2+ waves. J Physiol 2010; 588:3983-4005. [PMID: 20736418 DOI: 10.1113/jphysiol.2010.193300] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This study examined whether elevated intravascular pressure stimulates asynchronous Ca(2+) waves in cerebral arterial smooth muscle cells and if their generation contributes to myogenic tone development. The endothelium was removed from rat cerebral arteries, which were then mounted in an arteriograph, pressurized (20-100 mmHg) and examined under a variety of experimental conditions. Diameter and membrane potential (V(M)) were monitored using conventional techniques; Ca(2+) wave generation and myosin light chain (MLC(20))/MYPT1 (myosin phosphatase targeting subunit) phosphorylation were assessed by confocal microscopy and Western blot analysis, respectively. Elevating intravascular pressure increased the proportion of smooth muscle cells firing asynchronous Ca(2+) waves as well as event frequency. Ca(2+) wave augmentation occurred primarily at lower intravascular pressures (<60 mmHg) and ryanodine, a plant alkaloid that depletes the sarcoplasmic reticulum (SR) of Ca(2+), eliminated these events. Ca(2+) wave generation was voltage insensitive as Ca(2+) channel blockade and perturbations in extracellular [K(+)] had little effect on measured parameters. Ryanodine-induced inhibition of Ca(2+) waves attenuated myogenic tone and MLC(20) phosphorylation without altering arterial V(M). Thapsigargin, an SR Ca(2+)-ATPase inhibitor also attenuated Ca(2+) waves, pressure-induced constriction and MLC(20) phosphorylation. The SR-driven component of the myogenic response was proportionally greater at lower intravascular pressures and subsequent MYPT1 phosphorylation measures revealed that SR Ca(2+) waves facilitated pressure-induced MLC(20) phosphorylation through mechanisms that include myosin light chain phosphatase inhibition. Cumulatively, our findings show that mechanical stimuli augment Ca(2+) wave generation in arterial smooth muscle and that these transient events facilitate tone development particularly at lower intravascular pressures by providing a proportion of the Ca(2+) required to directly control MLC(20) phosphorylation.
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Affiliation(s)
- Rania E Mufti
- Hotchkiss Brain Institute, Libin Cardiovascular Institute, Department of Physiology & Pharmacology, University of Calgary, Alberta, Canada
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Boé DM, Richens TR, Horstmann SA, Burnham EL, Janssen WJ, Henson PM, Moss M, Vandivier RW. Acute and chronic alcohol exposure impair the phagocytosis of apoptotic cells and enhance the pulmonary inflammatory response. Alcohol Clin Exp Res 2010; 34:1723-32. [PMID: 20608904 DOI: 10.1111/j.1530-0277.2010.01259.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Alcohol abuse increases the risk for acute respiratory distress syndrome (ARDS). Efferocytosis, the clearance of apoptotic cells, is important in the resolution of inflammation and is regulated by RhoA and rho kinase (ROCK) activation. The effects of alcohol on pulmonary Rho pathway activation and efferocytosis have not been determined. We hypothesize that acute and chronic alcohol exposure impair pulmonary efferocytosis, leading to heightened inflammation during ARDS. METHODS For in vivo experiments, C57BL/6 mice received either a single intraperitoneal injection of alcohol or chronic ethanol-in-water for 8 weeks prior to intratracheal instillation of apoptotic cells or lipopolysaccharide (LPS). Bronchoalveolar lavage (BAL) was performed for cells counts, calculation of the phagocytic index (PI), and Rho activity measurements. For in vitro studies, primary alveolar macrophages were cultured in alcohol (25-100 mM) and then co-cultured with apoptotic cells. RhoA activity was determined following alcohol exposure, and the PI was determined before and after treatment with the ROCK inhibitor, Y27632. RESULTS Acute alcohol exposure was associated with impaired efferocytosis. Following LPS exposure, acute alcohol exposure was also associated with increased BAL neutrophils. Chronic alcohol exposure alone did not alter efferocytosis. However, following exposure to LPS, chronic alcohol exposure was associated with both impaired efferocytosis and increased BAL neutrophils. In vitro alcohol exposure caused a dose-dependent decrease in efferocytosis. Despite the fact that RhoA activity was decreased by alcohol exposure and RhoA inhibition did not alter the effects of alcohol on efferocytosis, treatment with the Rho kinase inhibitor, Y27632, reversed the effects of alcohol on efferocytosis. CONCLUSIONS Acute alcohol exposure impairs pulmonary efferocytosis, whereas exposure to chronic alcohol is only associated with impaired efferocytosis following LPS-induced lung injury. Both forms of alcohol exposure are associated with increased alveolar neutrophil numbers in response to LPS. The acute effects of alcohol on efferocytosis appear to be mediated, at least in part, by RhoA-independent activation of ROCK. Further studies are needed to dissect the differences between the effects of acute and chronic alcohol exposure on efferocytosis and to determine the effects of alcohol on alternative activators of ROCK.
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Affiliation(s)
- Darren M Boé
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Anschutz Medical Campus, Research 2, Box C272, 9th Floor, 12700 East 19th Avenue, Aurora, CO 80045, USA.
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Wirth A. Rho kinase and hypertension. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1276-84. [PMID: 20460153 DOI: 10.1016/j.bbadis.2010.05.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 04/16/2010] [Accepted: 05/01/2010] [Indexed: 11/26/2022]
Abstract
Arterial hypertension is a multifactorial disease that is characterised by increased peripheral vascular resistance often accompanied by smooth muscle cell hypertrophy and proliferation. Rho kinases (ROCKs) are the most extensively studied effectors of the small G-protein RhoA and abnormalities in RhoA/ROCK signalling have been observed in various cardiovascular disease including hypertension. The RhoA/ROCK-pathway is a key player in different smooth muscle cell functions including contractility, proliferation and migration. Furthermore, there is extensive crosstalk between RhoA/ROCK- and NO-signalling. Therefore, not only ROCK inhibitors but also NO-donators or pleiotropic agents like statins exert their beneficial effects on the cardiovascular system at least in part via Rho/Rho-kinase.
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Affiliation(s)
- Angela Wirth
- Max-Planck-Institute for Heart and Lung Research, Dept. of Pharmacology, Ludwigstraße 43, 61231 Bad Nauheim, Germany.
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González-Montelongo MC, Marín R, Gómez T, Marrero-Alonso J, Díaz M. Androgens induce nongenomic stimulation of colonic contractile activity through induction of calcium sensitization and phosphorylation of LC20 and CPI-17. Mol Endocrinol 2010; 24:1007-23. [PMID: 20207835 DOI: 10.1210/me.2009-0472] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We show that androgens, testosterone and 5alpha-dihydrotestosterone (DHT), acutely (approximately 40 min) provoke the mechanical potentiation of spontaneous and agonist-induced contractile activity in mouse colonic longitudinal smooth muscle. The results using flutamide, finasteride, cycloheximide, and actinomycin D indicate that androgen-induced potentiation is dependent on androgen receptors, requires reduction of testosterone to DHT, and occurs independently of transcriptional and translational events. Using permeabilized colonic smooth muscle preparations, we could demonstrate that mechanical potentiation is entirely due to calcium sensitization of contractile machinery. In addition, DHT (10 nm) increased phosphorylation of both 20-kDa myosin light chain (LC(20)) [regulatory myosin light chain, (MLC)] and CPI-17 (an endogenous inhibitor of MLC phosphatase). Paralleling these findings, inhibition of Rho-associated Rho kinase (ROK) and/or protein kinase C (PKC) with, respectively, Y27632 and chelerythrine, prevented LC(20) phosphorylation and abolished calcium sensitization. In addition, inhibition of ROK prevents CPI-17 phosphorylation, indicating that ROK is located upstream PKC-mediated CPI-17 modulation in the signalling cascade. Additionally, androgens induce a rapid activation of RhoA and its translocation to the plasma membrane to activate ROK. The results demonstrate that androgens induce sensitization of colonic smooth muscle to calcium through activation of ROK, which in turn, activates PKC to induce CPI-17 phosphorylation. Activation of this pathway induces a potent steady stimulation of LC(20) by inhibiting MLC phosphatase and displacing the equilibrium of the regulatory subunit towards its phosphorylated state. This is the first demonstration that colonic smooth muscle is a physiological target for androgen hormones, and that androgens modulate force generation of smooth muscle contractile machinery through nongenomic calcium sensitization pathways.
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Affiliation(s)
- María C González-Montelongo
- Laboratory of Membrane Physiology and Biophysics, Department of Animal Biology, University of La Laguna, Tenerife 38206, Spain
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Puetz S, Lubomirov LT, Pfitzer G. Regulation of smooth muscle contraction by small GTPases. Physiology (Bethesda) 2010; 24:342-56. [PMID: 19996365 DOI: 10.1152/physiol.00023.2009] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Next to changes in cytosolic [Ca(2+)], members of the Rho subfamily of small GTPases, in particular Rho and its effector Rho kinase, also known as ROK or ROCK, emerged as key regulators of smooth muscle function in health and disease. In this review, we will focus on the regulation of the contractile machinery by Rho/ROK signaling and its interaction with PKC and cyclic nucleotide signaling. We will briefly discuss the emerging evidence that remodeling of cortical actin is necessary for contraction.
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Affiliation(s)
- Sandra Puetz
- Institut für Vegetative Physiologie, Universitaet Koeln, Koeln, Germany,
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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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Kawaguchi T, Satoh KI, Kuji A, Joh S. Features of distinct contractions induced with a high and a low concentration of KCl, noradrenaline, and histamine in swine lingual artery. Naunyn Schmiedebergs Arch Pharmacol 2010; 381:107-20. [PMID: 20054523 DOI: 10.1007/s00210-009-0486-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 12/11/2009] [Indexed: 12/23/2022]
Abstract
We investigated the features of swine lingual artery contraction induced with different strengths of stimulation. Endothelium-denuded artery rings were contracted with two concentrations of KCl, noradrenaline, and histamine with or without Y-27632, sodium nitroprusside (SNP), 2,2-diphenyl-1,3,2-oxaza-borolidine internal salt (2- APB), and extracellular Ca2+. While stored at 5 degrees C up to 3 days, artery rings remained active to strong stimulation but became inactive to weak stimulation if prior warming was lacking. Artery rings contracted slowly and progressively to weak stimulation but rapidly to strong stimulation and then kept a plateau or slightly relaxed. Y-27632, SNP, and 2-APB, irrespective of extracellular Ca2+, attenuated weak-stimulation-induced contractions to much greater extents except that 2-APB similarly diminished contractions to both noradrenaline concentrations. Without extracellular Ca2+, transitory contractions occurred with one peak to strong stimulation and two small peaks to weak stimulation, though one full peak to both noradrenaline concentrations. Artery rings lost stimulant responsiveness when extracellular Ca2+ was absent, but subsequent Ca2+ reintroduction without coexisting stimulant triggered transient contractions, which were as large as contractions to weak stimulation with extracellular Ca2+ and ceased with Y-27632, SNP, and 2-APB. These results collectively suggest that, in the lingual artery, its contraction properties shift coupling with strengths of both receptor- and voltage-mediated stimulation, with the tonic-like component being dominant in weak-stimulation-induced contraction.
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Affiliation(s)
- Takaki Kawaguchi
- Department of Biochemistry, School of Dentistry, Iwate Medical University, Morioka 020-8505, Japan.
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RATTAN SATISH, PHILLIPS BENJAMINR, MAXWELL PINCKNEYJ. RhoA/Rho-kinase: pathophysiologic and therapeutic implications in gastrointestinal smooth muscle tone and relaxation. Gastroenterology 2010; 138:13-8.e1-3. [PMID: 19931260 PMCID: PMC5599165 DOI: 10.1053/j.gastro.2009.11.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- SATISH RATTAN
- Department of Medicine, Division of Gastroenterology & Hepatology, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA
| | - BENJAMIN R. PHILLIPS
- Department of Surgery, Division of Colon and Rectal Surgery, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA
| | - PINCKNEY J. MAXWELL
- Department of Surgery, Division of Colon and Rectal Surgery, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA
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Substrate specificity and inhibitors of LRRK2, a protein kinase mutated in Parkinson's disease. Biochem J 2009; 424:47-60. [PMID: 19740074 DOI: 10.1042/bj20091035] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The LRRK2 (leucine-rich repeat protein kinase-2) is mutated in a significant number of Parkinson's disease patients, but little is known about its regulation and function. A common mutation changing Gly2019 to serine enhances catalytic activity, suggesting that small-molecule inhibitors might have utility in treating Parkinson's disease. We employed various approaches to explore the substrate-specificity requirements of LRRK2 and elaborated a peptide substrate termed Nictide, that had 20-fold lower Km and nearly 2-fold higher Vmax than the widely deployed LRRKtide substrate. We demonstrate that LRRK2 has marked preference for phosphorylating threonine over serine. We also observed that several ROCK (Rho kinase) inhibitors such as Y-27632 and H-1152, suppressed LRRK2 with similar potency to which they inhibited ROCK2. In contrast, GSK429286A, a selective ROCK inhibitor, did not significantly inhibit LRRK2. We also identified a mutant LRRK2[A2016T] that was normally active, but resistant to H-1152 and Y-27632, as well as sunitinib, a structurally unrelated multikinase inhibitor that, in contrast with other compounds, suppresses LRRK2, but not ROCK. We have also developed the first sensitive antibody that enables measurement of endogenous LRRK2 protein levels and kinase activity as well as shRNA (short hairpin RNA) methods to reduce LRRK2 expression. Finally, we describe a pharmacological approach to validate whether substrates are phosphorylated by LRRK2 and use this to provide evidence that LRRK2 may not be rate-limiting for the phosphorylation of the proposed substrate moesin. The findings of the present study will aid with the investigation of LRRK2.
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Frei E, Huster M, Smital P, Schlossmann J, Hofmann F, Wegener JW. Calcium-dependent and calcium-independent inhibition of contraction by cGMP/cGKI in intestinal smooth muscle. Am J Physiol Gastrointest Liver Physiol 2009; 297:G834-9. [PMID: 19628652 DOI: 10.1152/ajpgi.00095.2009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
cGMP-dependent protein kinase I (cGKI) induces relaxation of smooth muscle via several pathways that include inhibition of intracellular Ca(2+) signaling and/or involve activation of myosin phosphatase. In the present study, we investigated these mechanisms comparatively in colon and jejunum longitudinal smooth muscle from mice. In simultaneous recordings from colon muscle, 8-bromo-cGMP (8-Br-cGMP) reduced both carbachol-induced tension and carbachol-induced increase in intracellular Ca(2+) concentration ([Ca(2+)](i)). These effects of 8-Br-cGMP were absent in colon from mice carrying a mutated inositol-1,4,5 trisphosphate receptor I-associated G kinase substrate (IRAG) gene or lacking cGKI. However, in jejunum, 8-Br-cGMP reduced carbachol-induced tension but did not change corresponding [Ca(2+)](i) signals. This setting was also observed in jejunum from mice carrying a mutated IRAG gene, whereas no response to 8-Br-cGMP was observed in jejunum from mice lacking cGKI. After inhibition of phosphatase activity by calyculin A, 8-Br-cGMP did not relax jejunum but still relaxed colon muscle. In Western blot analysis, 8-Br-cGMP reduced the signal for phosphorylated MYPT-1 in carbachol-stimulated jejunum but not in colon. These results suggest that cGMP/cGKI signaling differentially inhibits contraction in the muscles investigated: in jejunum, inhibition is performed without changing [Ca(2+)](i) and is dependent on phosphatase activity, whereas in colon, inhibition is mediated by inhibition of [Ca(2+)](i) signals.
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Affiliation(s)
- Eva Frei
- Institut für Pharmakologie und Toxikologie, Technische Universität München, Munich, Germany
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Tian B, Kaufman PL. Combined Effects of H7 and Pilocarpine on Anterior Segment Physiology in Monkey Eyes. Curr Eye Res 2009; 32:491-500. [PMID: 17612965 DOI: 10.1080/02713680701397104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To determine, in monkey eyes in vivo if low doses of the cholinergic agonist pilocarpine (PILO) can enhance the outflow facility responses to a maximal dose of the serine-threonine kinase inhibitor H7 without producing apparent miosis and/or excessive accommodation. METHODS Outflow facility was determined by two-level constant pressure perfusion in living monkeys after 24.5 microM phenylephrine (PE) bilaterally (stimulates the iris dilator without influencing the iris sphincter, ciliary muscle, or outflow facility, and facilitates the measurement of miosis and accommodation), 24.5 microM PE + 300 microM H7 (maximal outflow facility-effective dose) bilaterally, or 24.5 microM PE + 300 microM H7 +/- 2 or 10 microM PILO (2 microM PILO alone does not significantly increase outflow facility or accommodation but moderately constricts the pupil; 10 microM PILO is a threshold outflow facility-effective dose) in opposite eyes. Pupil diameter (Vernier calipers) and accommodation (coincidence refractometer) were measured essentially concurrently. RESULTS Outflow facility in the PE + H7 + 10 microM PILO eyes was 73% higher than that in the PE + H7 eyes (n = 6; p < 0.05). Accommodation was greater (n = 4; 2.6 vs. 0.6 D; p < 0.05) and pupil diameter was smaller (n = 6; 3.4 vs. 7.6 mm; p < 0.02) in the former than in the latter. No significant difference in outflow facility, accommodation or pupil diameter was observed between the PE + H7 + 2 microM PILO eyes and the PE + H7 eyes. CONCLUSIONS In living monkeys, 10 microM PILO, but not 2 microM PILO, enhances the 300 microM H7-induced increase in outflow facility with only approximately 3 diopters of accommodation, whereas 300 microM H7 partially inhibits the 2 microM PILO-induced, but not the 10 microM PILO-induced miosis. This suggests that, although the miosis following the threshold facility-effective dose of PILO cannot be reduced by combination with the maximal facility-effective dose of H7, the combination may at least benefit young glaucoma or ocular hypertension patients who are bothered by PILO-induced myopia more than by miosis.
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Affiliation(s)
- Baohe Tian
- Department of Ophthalmology & Visual Sciences, University of Wisconsin, Madison, Wisconsin 53705-3611, USA
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Li T, Liu D, Wang Z. Microarray-based Raman spectroscopic assay for kinase inhibition by gold nanoparticle probes. Biosens Bioelectron 2009; 24:3335-9. [DOI: 10.1016/j.bios.2009.04.033] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 04/20/2009] [Accepted: 04/22/2009] [Indexed: 10/20/2022]
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Freitas MR, Eto M, Kirkbride JA, Schott C, Sassard J, Stoclet JC. Y27632, a Rho-activated kinase inhibitor, normalizes dysregulation in alpha1-adrenergic receptor-induced contraction of Lyon hypertensive rat artery smooth muscle. Fundam Clin Pharmacol 2009; 23:169-78. [PMID: 19298234 DOI: 10.1111/j.1472-8206.2008.00658.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RhoA-activated kinase (ROK) is involved in the disorders of smooth muscle contraction found in hypertension model animals and patients. We examined whether the alpha1-adrenergic receptor agonist-induced ROK signal is perturbed in resistance small mesentery artery (SMA) of Lyon genetically hypertensive (LH) rats, using a ROK antagonist, Y27632. Smooth muscle strips of SMA and aorta were isolated from LH and Lyon normotensive (LN) rats. After Ca(2+)-depletion and pre-treatment with phenylephrine (PE), smooth muscle contraction was induced by serial additions of CaCl(2). In LH SMA Ca(2+) permeated cells to a lesser extent as compared with LN SMA, while CaCl(2)-induced contraction of LH SMA was greater than that of LN SMA, indicating a higher ratio of force to Ca(2+) in LH SMA contraction (Ca(2+) sensitization). No hyper-contraction was observed in LH aorta tissues. Treatment of LH SMA with Y27632 restored both Ca(2+) permeability and Ca(2+)-force relationship to levels seen for LN SMA. In response to PE stimulation, phosphorylation of CPI-17, a phosphorylation-dependent myosin phosphatase inhibitor protein, and MYPT1 at Thr853, the inhibitory phosphorylation site of the myosin phosphatase regulatory subunit, was increased in LN SMA, but remained unchanged in LH SMA. These results suggest that the disorder in ROK-dependent Ca(2+) permeability and Ca(2+)-force relationship is responsible for LH SMA hyper-contraction. Unlike other hypertensive models, the ROK-induced hyper-contractility of LH SMA is independent of MYPT1 and CPI-17 phosphorylation, which suggests that ROK-mediated inhibition of myosin phosphatase does not affect SMA hyper-contractility in LH SMA cells.
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Affiliation(s)
- Maria Regina Freitas
- Pharmacologie et Physico-chimie des Interactions Cellulaires et Moléculaires, UMR CNRS 7034, Université Louis Pasteur de Strasbourg, Faculté de Pharmacie, Illkirch-Cedex, France
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Baek I, Jeon SB, Kim J, Seok YM, Song MJ, Chae SC, Jun JE, Park WH, Kim IK. A ROLE FOR RHO-KINASE IN Ca2+-INDEPENDENT CONTRACTIONS INDUCED BY PHORBOL-12,13-DIBUTYRATE. Clin Exp Pharmacol Physiol 2009; 36:256-61. [DOI: 10.1111/j.1440-1681.2008.05045.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Poley RN, Dosier CR, Speich JE, Miner AS, Ratz PH. Stimulated calcium entry and constitutive RhoA kinase activity cause stretch-induced detrusor contraction. Eur J Pharmacol 2008; 599:137-45. [PMID: 18929558 DOI: 10.1016/j.ejphar.2008.09.045] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 09/25/2008] [Accepted: 09/29/2008] [Indexed: 11/26/2022]
Abstract
Urinary bladder wall muscle (i.e., detrusor smooth muscle; DSM) contracts in response to a quick-stretch, but this response is neither fully characterized, nor completely understood at the subcellular level. Strips of rabbit DSM were quick-stretched (5 ms) and held isometric for 10 s to measure the resulting peak quick-stretch contractile response (PQSR). The ability of selective Ca(2+) channel blockers and kinase inhibitors to alter the PQSR was measured, and the phosphorylation levels of myosin light chain (MLC) and myosin phosphatase targeting regulatory subunit (MYPT1) were recorded. DSM responded to a quick-stretch with a biphasic response consisting of an initial contraction peaking at 0.24+/-0.02-fold the maximum KCl-induced contraction (F(o)) by 1.48+/-0.17 s (PQSR) before falling to a weaker tonic (10 s) level (0.12+/-0.03-fold F(o)). The PQSR was dependent on the rate and degree of muscle stretch, displayed a refractory period, and was converted to a sustained response in the presence of muscarinic receptor stimulation. The PQSR was inhibited by nifedipine, 2-aminoethoxydiphenyl borate (2-APB), 100 microM gadolinium and Y-27632, but not by atropine, 10 microM gadolinium, LOE-908, cyclopiazonic acid, or GF-109203X. Y-27632 and nifedipine abolished the increase in MLC phosphorylation induced by a quick-stretch. Y-27632, but not nifedipine, inhibited basal MYPT1 phosphorylation, and a quick-stretch failed to increase phosphorylation of this rhoA kinase (ROCK) substrate above the basal level. These data support the hypothesis that constitutive ROCK activity is required for a quick-stretch to activate Ca(2+) entry and cause a myogenic contraction of DSM.
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Affiliation(s)
- Rainer N Poley
- Department of Biochemistry & Molecular Biology, Virginia Commonwealth University, School of Medicine, PO Box 980614, Richmond, VA 23298-0614, United States
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Mizuno Y, Isotani E, Huang J, Ding H, Stull JT, Kamm KE. Myosin light chain kinase activation and calcium sensitization in smooth muscle in vivo. Am J Physiol Cell Physiol 2008; 295:C358-64. [PMID: 18524939 DOI: 10.1152/ajpcell.90645.2007] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca(2+)/calmodulin (CaM)-dependent phosphorylation of myosin regulatory light chain (RLC) in smooth muscle by myosin light chain kinase (MLCK) and dephosphorylation by myosin light chain phosphatase (MLCP) are subject to modulatory cascades that influence the sensitivity of RLC phosphorylation and hence contraction to intracellular Ca(2+) concentration ([Ca(2+)](i)). We designed a CaM-sensor MLCK containing smooth muscle MLCK fused to two fluorescent proteins linked by the MLCK CaM-binding sequence to measure kinase activation in vivo and expressed it specifically in mouse smooth muscle. In phasic bladder muscle, there was greater RLC phosphorylation and force relative to MLCK activation and [Ca(2+)](i) with carbachol (CCh) compared with KCl treatment, consistent with agonist-dependent inhibition of MLCP. The dependence of force on MLCK activity was nonlinear such that at higher concentrations of CCh, force increased with no change in the net 20% activation of MLCK. A significant but smaller amount of MLCK activation was found during the sustained contractile phase. MLCP inhibition may occur through RhoA/Rho-kinase and/or PKC with phosphorylation of myosin phosphatase targeting subunit-1 (MYPT1) and PKC-potentiated phosphatase inhibitor (CPI-17), respectively. CCh treatment, but not KCl, resulted in MYPT1 and CPI-17 phosphorylation. Both Y27632 (Rho-kinase inhibitor) and calphostin C (PKC inhibitor) reduced CCh-dependent force, RLC phosphorylation, and phosphorylation of MYPT1 (Thr694) without changing MLCK activation. Calphostin C, but not Y27632, also reduced CCh-induced phosphorylation of CPI-17. CCh concentration responses showed that phosphorylation of CPI-17 was more sensitive than MYPT1. Thus the onset of agonist-induced contraction in phasic smooth muscle results from the rapid and coordinated activation of MLCK with hierarchical inhibition of MLCP by CPI-17 and MYPT1 phosphorylation.
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Affiliation(s)
- Yusuke Mizuno
- Dept. Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9040, USA
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G(q)-dependent signalling by the lysophosphatidic acid receptor LPA(3) in gastric smooth muscle: reciprocal regulation of MYPT1 phosphorylation by Rho kinase and cAMP-independent PKA. Biochem J 2008; 411:543-51. [PMID: 18237278 DOI: 10.1042/bj20071299] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The present study characterized the signalling pathways initiated by the bioactive lipid, LPA (lysophosphatidic acid) in smooth muscle. Expression of LPA(3) receptors, but not LPA(1) and LPA(2), receptors was demonstrated by Western blot analysis. LPA stimulated phosphoinositide hydrolysis, PKC (protein kinase C) and Rho kinase (Rho-associated kinase) activities: stimulation of all three enzymes was inhibited by expression of the G(alphaq), but not the G(alphai), minigene. Initial contraction and MLC(20) (20 kDa regulatory light chain of myosin II) phosphorylation induced by LPA were abolished by inhibitors of PLC (phospholipase C)-beta (U73122) or MLCK (myosin light-chain kinase; ML-9), but were not affected by inhibitors of PKC (bisindolylmaleimide) or Rho kinase (Y27632). In contrast, sustained contraction, and phosphorylation of MLC(20) and CPI-17 (PKC-potentiated inhibitor 17 kDa protein) induced by LPA were abolished selectively by bisindolylmaleimide. LPA-induced activation of IKK2 {IkappaB [inhibitor of NF-kappaB (nuclear factor kappaB)] kinase 2} and PKA (protein kinase A; cAMP-dependent protein kinase), and degradation of IkappaBalpha were blocked by the RhoA inhibitor (C3 exoenzyme) and in cells expressing dominant-negative mutants of IKK2(K44A) or RhoA(N19RhoA). Phosphorylation by Rho kinase of MYPT1 (myosin phosphatase targeting subunit 1) at Thr(696) was masked by phosphorylation of MYPT1 at Ser(695) by PKA derived from IkappaB degradation via RhoA, but unmasked in the presence of PKI (PKA inhibitor) or C3 exoenzyme and in cells expressing IKK2(K44A). We conclude that LPA induces initial contraction which involves activation of PLC-beta and MLCK and phosphorylation of MLC(20), and sustained contraction which involves activation of PKC and phosphorylation of CPI-17 and MLC(20). Although Rho kinase was activated, phosphorylation of MYPT1 at Thr(696) by Rho kinase was masked by phosphorylation of MYPT1 at Ser(695) via cAMP-independent PKA derived from the NF-kappaB pathway.
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