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Dee RA, Mangum KD, Bai X, Mack CP, Taylor JM. Druggable targets in the Rho pathway and their promise for therapeutic control of blood pressure. Pharmacol Ther 2019; 193:121-134. [PMID: 30189292 PMCID: PMC7235948 DOI: 10.1016/j.pharmthera.2018.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The prevalence of high blood pressure (also known as hypertension) has steadily increased over the last few decades. Known as a silent killer, hypertension increases the risk for cardiovascular disease and can lead to stroke, heart attack, kidney failure and associated sequela. While numerous hypertensive therapies are currently available, it is estimated that only half of medicated patients exhibit blood pressure control. This signifies the need for a better understanding of the underlying cause of disease and for more effective therapies. While blood pressure homeostasis is very complex and involves the integrated control of multiple body systems, smooth muscle contractility and arterial resistance are important contributors. Strong evidence from pre-clinical animal models and genome-wide association studies indicate that smooth muscle contraction and BP homeostasis are governed by the small GTPase RhoA and its downstream target, Rho kinase. In this review, we summarize the signaling pathways and regulators that impart tight spatial-temporal control of RhoA activity in smooth muscle cells and discuss current therapeutic strategies to target these RhoA pathway components. We also discuss known allelic variations in the RhoA pathway and consider how these polymorphisms may affect genetic risk for hypertension and its clinical manifestations.
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Affiliation(s)
- Rachel A Dee
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kevin D Mangum
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Xue Bai
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Christopher P Mack
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Joan M Taylor
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA.
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Bai X, Dee R, Mangum KD, Mack CP, Taylor JM. RhoA signaling and blood pressure: The consequence of failing to “Tone it Down”. World J Hypertens 2016; 6:18-35. [DOI: 10.5494/wjh.v6.i1.18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/24/2015] [Accepted: 01/22/2016] [Indexed: 02/06/2023] Open
Abstract
Uncontrolled high blood pressure is a major risk factor for heart attack, stroke, and kidney failure and contributes to an estimated 25% of deaths worldwide. Despite numerous treatment options, estimates project that reasonable blood pressure (BP) control is achieved in only about half of hypertensive patients. Improvements in the detection and management of hypertension will undoubtedly be accomplished through a better understanding of the complex etiology of this disease and a more comprehensive inventory of the genes and genetic variants that influence BP regulation. Recent studies (primarily in pre-clinical models) indicate that the small GTPase RhoA and its downstream target, Rho kinase, play an important role in regulating BP homeostasis. Herein, we summarize the underlying mechanisms and highlight signaling pathways and regulators that impart tight spatial-temporal control of RhoA activity. We also discuss known allelic variations in the RhoA pathway and consider how these polymorphisms may affect genetic risk for hypertension and its clinical manifestations. Finally, we summarize the current (albeit limited) clinical data on the efficacy of targeting the RhoA pathway in hypertensive patients.
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Vukićević T, Schulz M, Faust D, Klussmann E. The Trafficking of the Water Channel Aquaporin-2 in Renal Principal Cells-a Potential Target for Pharmacological Intervention in Cardiovascular Diseases. Front Pharmacol 2016; 7:23. [PMID: 26903868 PMCID: PMC4749865 DOI: 10.3389/fphar.2016.00023] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 01/25/2016] [Indexed: 01/13/2023] Open
Abstract
Arginine-vasopressin (AVP) stimulates the redistribution of water channels, aquaporin-2 (AQP2) from intracellular vesicles into the plasma membrane of renal collecting duct principal cells. By this AVP directs 10% of the water reabsorption from the 170 L of primary urine that the human kidneys produce each day. This review discusses molecular mechanisms underlying the AVP-induced redistribution of AQP2; in particular, it provides an overview over the proteins participating in the control of its localization. Defects preventing the insertion of AQP2 into the plasma membrane cause diabetes insipidus. The disease can be acquired or inherited, and is characterized by polyuria and polydipsia. Vice versa, up-regulation of the system causing a predominant localization of AQP2 in the plasma membrane leads to excessive water retention and hyponatremia as in the syndrome of inappropriate antidiuretic hormone secretion (SIADH), late stage heart failure or liver cirrhosis. This article briefly summarizes the currently available pharmacotherapies for the treatment of such water balance disorders, and discusses the value of newly identified mechanisms controlling AQP2 for developing novel pharmacological strategies. Innovative concepts for the therapy of water balance disorders are required as there is a medical need due to the lack of causal treatments.
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Affiliation(s)
- Tanja Vukićević
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Maike Schulz
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Dörte Faust
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association Berlin, Germany
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz AssociationBerlin, Germany; German Centre for Cardiovascular ResearchBerlin, Germany
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Rozic G, Lupowitz Z, Piontkewitz Y, Zisapel N. Dynamic changes in neurexins' alternative splicing: role of Rho-associated protein kinases and relevance to memory formation. PLoS One 2011; 6:e18579. [PMID: 21533271 PMCID: PMC3075264 DOI: 10.1371/journal.pone.0018579] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 03/13/2011] [Indexed: 12/28/2022] Open
Abstract
The three neurexins genes (NRXN1/2/3) encode polymorphic synaptic membrane proteins that are involved in cognitive functioning. Neurexins' selectivity of function is presumably conferred through differential use of 2 promoters and 5 alternative splicing sites (SS#1/2/3/4/5). In day-old rat brain neurons grown in culture, activation (depolarization) induces reversible, calcium dependent, repression of NRXN2α SS#3 insert. The effects of depolarization on NRXN1/2/3α splicing and biochemical pathways mediating them were further studied in these neurons. NRXN1/2/3α splicing in the course of memory formation in vivo was also explored, using fear conditioning paradigm in rats in which the animals were trained to associate an aversive stimulus (electrical shock) with a neutral context (a tone), resulting in the expression of fear responses to the neutral context. In the cultured neurons depolarization induced, beside NRXN2α SS#3, repression of SS#3 and SS#4 exons in NRXN3α but not NRXN1α. The repressions were mediated by the calcium/protein kinase C/Rho-associated protein kinase (ROCK) pathway. Fear conditioning induced significant and transient repressions of the NRXN1/2/3α SS#4 exons in the rat hippocampus. ROCK inhibition prior to training attenuated the behavioral fear response, the NRXN1/2/3α splicing repressions and subsequent recovery and the levels of excitatory (PSD95) and inhibitory (gephyrin) synaptic proteins in the hippocampus. No such effects were observed in the prefrontal cortex. Significant correlations existed between the fear response and hippocampal NRXN3α and NRXN2α SS#4 inserts as well as PSD95 protein levels. Hippocampal NRXN1α SS#4 insert and gephyrin levels did not correlate with the behavioral response but were negatively correlated with each other. These results show for the first time dynamic, experience related changes in NRXN1/2/3α alternative splicing in the rat brain and a role for ROCK in them. Specific neurexins' transcripts may be involved in synaptic remodeling occurring at an intermediate (hours) time scale in the course of memory formation.
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Affiliation(s)
- Gabriela Rozic
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Zipora Lupowitz
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Yael Piontkewitz
- Department of Psychology, Faculty of Social Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Nava Zisapel
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
- * E-mail:
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Xiao Y, Li CM, Wang S, Shi J, Ooi CP. Incorporation of collagen in poly(3,4-ethylenedioxythiophene) for a bifunctional film with high bio- and electrochemical activity. J Biomed Mater Res A 2010; 92:766-72. [DOI: 10.1002/jbm.a.32412] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Yodoi R, Tamba S, Morimoto K, Segi-Nishida E, Nishihara M, Ichikawa A, Narumiya S, Sugimoto Y. RhoA/Rho kinase signaling in the cumulus mediates extracellular matrix assembly. Endocrinology 2009; 150:3345-52. [PMID: 19342461 PMCID: PMC2703534 DOI: 10.1210/en.2008-1449] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cumulus cells surround the oocyte and regulate the production and assembly of the extracellular matrix (ECM) around the cumulus-oocyte complex for its timely interaction with sperm in the oviduct. We recently found that C-C chemokines such as CCL2, CCL7, and CCL9 are produced and stimulate integrin-mediated ECM assembly in the postovulatory cumulus to protect eggs and that prostaglandin E(2)-EP2 signaling in the cumulus cells facilitates fertilization by suppressing this chemokine signaling, which otherwise results in fertilization failure by preventing sperm penetration through the cumulus ECM. However, it remains unknown as to what mechanisms underlie chemokine-induced cumulus ECM assembly. Here we report that inhibition of EP2 signaling or addition of CCL7 augments RhoA activation and induces the surface accumulation of integrin and the contraction of cumulus cells. Enhanced surface accumulation of integrin then stimulates the formation and assembly of fibronectin fibrils as well as induces cumulus ECM resistance to hyaluronidase and sperm penetration. These changes in the cumulus ECM as well as cell contraction are relieved by the addition of Y27632 or blebbistatin. These results suggest that chemokines induce integrin engagement to the ECM and consequent ECM remodeling through the RhoA/Rho kinase/actomyosin pathway, making the cumulus ECM barrier resistant to sperm penetration. Based on these results, we propose that prostaglandin E(2)-EP2 signaling negatively regulates chemokine-induced Rho/ROCK signaling in cumulus cells for successful fertilization.
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Affiliation(s)
- Rieko Yodoi
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
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Hammar E, Tomas A, Bosco D, Halban PA. Role of the Rho-ROCK (Rho-associated kinase) signaling pathway in the regulation of pancreatic beta-cell function. Endocrinology 2009; 150:2072-9. [PMID: 19106222 DOI: 10.1210/en.2008-1135] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Extracellular matrix has a beneficial impact on beta-cell spreading and function, but the underlying signaling pathways have yet to be fully elucidated. In other cell types, Rho, a well-characterized member of the family of Rho GTPases, and its effector Rho-associated kinase (ROCK), play an important role as downstream mediators of outside in signaling from extracellular matrix. Therefore, a possible role of the Rho-ROCK pathway in beta-cell spreading, actin cytoskeleton dynamics, and function was investigated. Rho was inhibited using a new cell-permeable version of C3 transferase, whereas the activity of ROCK was repressed using the specific ROCK inhibitors H-1152 and Y-27632. Inhibition of Rho and of ROCK increased spreading and improved both short-term and prolonged glucose-stimulated insulin secretion but had no impact on basal secretion. Inhibition of this pathway led to a depolymerization of the actin cytoskeleton. Furthermore, the impact of the inhibition of ROCK on stimulated insulin secretion was acute and reversible, suggesting that rapid signaling such as phosphorylation is involved. Finally, quantification of the activity of RhoA indicated that the extracellular matrix represses RhoA activity. Overall these results show for the first time that the Rho-ROCK signaling pathway contributes to the stabilization of the actin cytoskeleton and inhibits glucose-stimulated insulin secretion in primary pancreatic beta-cells. Furthermore, they indicate that inhibition of this pathway might be one of the mechanisms by which the extracellular matrix exerts its beneficial effects on pancreatic beta-cell function.
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Affiliation(s)
- Eva Hammar
- Department of Genetic Medicine and Development, University of Geneva, University Medical Center, Rue Michel Servet 1, 1211 Geneva 4, Switzerland
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Saitoh A, Yamada M, Yamada M, Kobayashi S, Hirose N, Honda K, Kamei J. ROCK inhibition produces anxiety-related behaviors in mice. Psychopharmacology (Berl) 2006; 188:1-11. [PMID: 16838139 DOI: 10.1007/s00213-006-0466-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Accepted: 06/01/2006] [Indexed: 11/28/2022]
Abstract
RATIONALE The role of Rho/Rho-associated kinase (ROCK) in regulating dendritic and axonal morphology during development has gained much attention. Very little is known, however, about the role of the Rho/ROCK pathway in emotional behavior. OBJECTIVE To investigate the role of ROCK in emotional behaviors. We examined how the ROCK inhibitor Y27632 affects the performance of mice on three behavioral tests that measure anxiety-related behaviors. RESULTS In the elevated plus-maze test, Y27632 (10 nmol, intracerebroventricular) induced a significant decrease in the percentage of time spent in the open arms and in the percentage of entries into open arms. In the fear conditioning test, Y27632-treated mice froze significantly more often and longer than did saline-treated mice. In the hole-board test, Y27632 significantly suppressed head-dipping behavior in Y27632-treated mice than in saline-treated mice. On the other hand, Y27632 did not produce on spontaneous alteration performance in the Y-maze test. These results indicate that ROCK inhibition increased anxiety-related behaviors. CONCLUSION Our findings suggest that the ROCK pathway is involved in the expression of anxiety- and fear-related behaviors. Furthermore, we propose that if the Rho/ROCK pathway plays an important role in mediating anxiety-related behaviors in humans, it may prove to be a novel system for anxiolytics to target.
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Affiliation(s)
- Akiyoshi Saitoh
- Department of Pathophysiology and Therapeutics, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, Tokyo, 142-8501, Japan
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Fukuda T, Takekoshi K, Nanmoku T, Ishii K, Isobe K, Kawakami Y. Inhibition of the RhoA/Rho kinase system attenuates catecholamine biosynthesis in PC 12 rat pheochromocytoma cells. Biochim Biophys Acta Gen Subj 2005; 1726:28-33. [PMID: 16219424 DOI: 10.1016/j.bbagen.2005.08.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2004] [Revised: 07/14/2005] [Accepted: 08/12/2005] [Indexed: 11/30/2022]
Abstract
The small GTPase, RhoA, and its downstream effecter Rho-kinase (ROK) are reported to be involved in various cellular functions, such as myosin light chain phosphorylation during smooth muscle contraction and exocytosis. Indeed, growing evidence suggests that the RhoA/Rho-kinase pathway plays an important role in regulating exocytosis in these cells. However, it is not known whether the RhoA/Rho-kinase pathway has an effect on catecholamine synthesis. Using the rat pheochromocytoma cell line, PC12, we examined the effects of either Rho-kinase inhibitor (Y27632) or RhoA inhibitor (C3 toxin) on nicotine-induced catecholamine biosynthesis. We show that nicotine (10 microM) induces a significant, though transient, increase in RhoA activation in these cells. Treatment with either Y27632 (1 microM) or C3 toxin (10 microg/ml) significantly inhibited the nicotine-induced increase of tyrosine hydroxylase (TH) mRNA and the corresponding enzyme activity. TH catalyzes the rate-limiting step in the biosynthesis of catecholamine. Y27632 significantly inhibited nicotine-induced phosphorylation of TH at Ser40 as well as Ser19, which are known to be phosphorylated by Ca(2+)/calmodulin kinase II. Furthermore, Y27632 (10 microM) as well as C3 toxin (10 microg/ml) significantly inhibited the nicotine-induced increase of TH at the protein level. Thus, we propose that activation of RhoA, and its downstream effecter Rho-kinase, is a prerequisite for catecholamine biosynthesis in PC12 cells. At the concentrations used in our experiments, Y27632 does not affect cAMP/PKA activity or PKC activity, indicating that the inhibitory effect of Y27632 can be attributed to the inhibition of Rho-kinase activity as observed in chromaffin cells. In contrast, neither Y27632 (10 microM) nor C3 toxin (10 microg/ml) significantly altered catecholamine secretion in PC12 cells. In conclusion, we have demonstrated that inhibition of the Rho/Rho-kinase pathway in chromaffin cells lowers TH activity, probably through CaMKII inhibition. By contrast, neither Y27632 nor C3 toxin affect the secretion of catecholamine.
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Affiliation(s)
- Toshiyuki Fukuda
- Department of Clinical Pathology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8575, Japan
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Binda AV, Kabbani N, Levenson R. Regulation of dense core vesicle release from PC12 cells by interaction between the D2 dopamine receptor and calcium-dependent activator protein for secretion (CAPS). Biochem Pharmacol 2005; 69:1451-61. [DOI: 10.1016/j.bcp.2005.02.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2004] [Accepted: 02/02/2005] [Indexed: 10/25/2022]
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Abstract
Rho-kinase is a signaling molecule that occurs downstream of the small GTPase Rho, which mediates various cellular functions. The Rho/Rho-kinase pathway plays an important role in pathophysiology and progression of various cardiovascular diseases such as hypertension, coronary vasospasm, angina pectoris, and restenosis after percutaneous coronary intervention, all of which are related to arteriosclerosis/atherosclerosis changes of the vasculature. Activation of the Rho/Rho-kinase pathway contributes to inflammatory and proliferative changes of the blood vessels and affects cardiac myocytes. Evidence from in vitro and in vivo studies suggests that Rho-kinase inhibitors have beneficial effects on cardiovascular diseases, particularly arteriosclerosis and coronary vasospasm. Furthermore, activation of the Rho/Rho-kinase pathway contributes to blood pressure regulation via the central sympathetic nervous system. There is evidence to suggest that Rho-kinase is involved in angiotensin II-induced cardiac hypertrophy and endothelial dysfunction, and preliminary data indicate that inhibition of Rho-kinase may be beneficial in vascular disorders such as pulmonary arterial hypertension and erectile dysfunction. Fasudil is currently the only Rho-kinase inhibitor available for clinical use and it is approved in Japan for the prevention of vasospasm in patients with subarachnoid hemorrhage. Emerging clinical data have shown that oral fasudil 80 mg three times daily is effective in preventing myocardial ischemia in patients with stable angina pectoris. Rho-kinase represents a new target for the management of cardiovascular diseases and further studies are needed to define the therapeutic potential of Rho-kinase inhibitors.
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Affiliation(s)
- Yoshitaka Hirooka
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Kyushu University, Fukuoka, Kyushu, Japan.
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Hirooka Y. Adenovirus-mediated gene transfer into the brain stem to examine cardiovascular function: role of nitric oxide and Rho-kinase. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2004; 84:233-49. [PMID: 14769438 DOI: 10.1016/j.pbiomolbio.2003.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The central nervous system plays an important role in the regulation of blood pressure via the sympathetic nervous system. Abnormal regulation of the sympathetic nerve activity is involved in the pathophysiology of hypertension. In particular, the brain stem, including the nucleus tractus solitarii (NTS) and the rostral ventrolateral medulla (RVLM), is a key site that controls and maintains blood pressure via the sympathetic nervous system. Nitric oxide (NO) is a unique molecule that influences sympathetic nerve activity. Rho-kinase is a downstream effector of the small GTPase, Rho, and is implicated in various cellular functions. We developed a technique to transfer adenovirus vectors encoding endothelial nitric oxide synthase and dominant-negative Rho-kinase into the NTS or the RVLM of rats in vivo. We applied this technique to hypertensive rats to explore the physiological significance of NO and Rho-kinase.
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Affiliation(s)
- Yoshitaka Hirooka
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
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Namekata K, Enokido Y, Iwasawa K, Kimura H. MOCA induces membrane spreading by activating Rac1. J Biol Chem 2004; 279:14331-7. [PMID: 14718541 DOI: 10.1074/jbc.m311275200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The modifier of cell adhesion protein (MOCA), or Dock3, initially identified as presenilin-binding protein (PBP), belongs to the Dock180 family of proteins and is localized specifically in neurons. Here we demonstrate that MOCA binds to Rac1 and enhances its activity, which leads to the activation of c-Jun NH(2)-terminal kinase (JNK) and causes changes in cell morphology. Farnesylated MOCA, which is localized in the plasma membrane, enhances the activation of Rac1 and JNK more markedly than wild-type MOCA, and cells expressing farnesylated MOCA show flattened morphology similar to those expressing a constitutive active mutant of Rac1, Rac1Q61L. On poly-d-lysine-coated dishes, endogenous MOCA is concentrated on the leading edge of broad membrane protrusions (lamellipodia) where actin filaments are co-localized. MOCA is also concentrated with actin on the growth cone in primary cultures of cortical neurons. These observations suggest that MOCA may induce cytoskeletal reorganization and changes in cell adhesion by regulating the activity of Rac1.
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Affiliation(s)
- Kazuhiko Namekata
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8551, Japan
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Tashiro K, Nagao T, Kurose H, Ichijo H, Urushidani T. Role of Rho in rabbit parietal cell. J Cell Physiol 2003; 197:409-17. [PMID: 14566970 DOI: 10.1002/jcp.10370] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rho is known as an important regulator of actin microfilament formation. We were led to study it because a dynamic rearrangement of actin filaments occurs during activation of gastric acid secretion. In order to use specific probes, the rabbit gastric gland culture system was employed and the various genes were expressed using adenovirus vector. When the constitutive active mutant of Rho (RhoAV14) was expressed, histamine- or carbachol-stimulated acid secretion monitored by (14)C-aminopyrine accumulation was inhibited. Conversely, expression of C3 toxin, the specific inhibitor of Rho, and expression of G(12/13)-specific regulator of G-protein signaling domain, the specific inhibitor of G(12/13) which is considered to be an upstream mediator of Rho, both potentiated acid secretion stimulated by the agonists. F-actin staining of parietal cell expressing RhoAV14 revealed that the microfilament supporting the intracellular canaliculi (not on the basolateral membrane) almost disappeared. No clear changes in the intracellular localization of Rho were observed during stimulation of parietal cell. In resting glands, the endogenous active form of Rho was relatively high, and it decreased during histamine stimulation. The finding that any treatment which inhibit Rho augment acid secretion whereas those that activate Rho inhibit secretion strongly suggests that the Rho-pathway conducts a negatively regulating signal in parietal cell activation, possibly via site-specific regulation of actin microfilaments.
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Affiliation(s)
- Keiichiro Tashiro
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo
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15
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Tamma G, Wiesner B, Furkert J, Hahm D, Oksche A, Schaefer M, Valenti G, Rosenthal W, Klussmann E. The prostaglandin E2 analogue sulprostone antagonizes vasopressin-induced antidiuresis through activation of Rho. J Cell Sci 2003; 116:3285-94. [PMID: 12829746 DOI: 10.1242/jcs.00640] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Arginine-vasopressin (AVP) facilitates water reabsorption in renal collecting duct principal cells by activation of vasopressin V2 receptors and the subsequent translocation of water channels (aquaporin-2, AQP2) from intracellular vesicles into the plasma membrane. Prostaglandin E2 (PGE2) antagonizes AVP-induced water reabsorption; the signaling pathway underlying the diuretic response is not known. Using primary rat inner medullary collecting duct (IMCD) cells, we show that stimulation of prostaglandin EP3 receptors induced Rho activation and actin polymerization in resting IMCD cells, but did not modify the intracellular localization of AQP2. However, AVP-, dibutyryl cAMP- and forskolin-induced AQP2 translocation was strongly inhibited. This inhibitory effect was independent of increases in cAMP and cytosolic Ca2+. In addition, stimulation of EP3 receptors inhibited the AVP-induced Rho inactivation and the AVP-induced F-actin depolymerization. The data suggest that the signaling pathway underlying the diuretic effects of PGE2 and probably those of other diuretic agents include cAMP- and Ca2+-independent Rho activation and F-actin formation.
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MESH Headings
- Actins/metabolism
- Animals
- Aquaporin 2
- Aquaporins/metabolism
- Biological Transport/drug effects
- Biological Transport/physiology
- Cell Membrane/metabolism
- Cells, Cultured
- Colforsin/pharmacology
- Cyclic AMP/metabolism
- Cytoplasmic Vesicles/metabolism
- Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide/pharmacology
- Dinoprostone/analogs & derivatives
- Dinoprostone/metabolism
- Dinoprostone/pharmacology
- Kidney Medulla/metabolism
- Microscopy, Fluorescence
- Models, Molecular
- Neurophysins/metabolism
- Prostaglandin Antagonists/pharmacology
- Protein Precursors/metabolism
- Rats
- Receptors, Prostaglandin E/antagonists & inhibitors
- Receptors, Prostaglandin E/metabolism
- Receptors, Vasopressin/metabolism
- Signal Transduction
- Vasopressins/metabolism
- rho GTP-Binding Proteins/metabolism
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Affiliation(s)
- Grazia Tamma
- Forschungsinstitut für Molekulare Pharmakologie, Campus Berlin-Buch, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
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Narita M, Takagi M, Aoki K, Kuzumaki N, Suzuki T. Implication of Rho-associated kinase in the elevation of extracellular dopamine levels and its related behaviors induced by methamphetamine in rats. J Neurochem 2003; 86:273-82. [PMID: 12871568 DOI: 10.1046/j.1471-4159.2003.01784.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A growing body of evidence suggests that several protein kinases are involved in the expression of pharmacological actions induced by a psychostimulant methamphetamine. The present study was designed to investigate the role of the Rho/Rho-associated kinase (ROCK)-dependent pathway in the expression of the increase in extracellular levels of dopamine in the nucleus accumbens and its related behaviors induced by methamphetamine in rats. Methamphetamine (1 mg/kg, subcutaneously) produced a substantial increase in extracellular levels of dopamine in the nucleus accumbens, with a progressive augmentation of dopamine-related behaviors including rearing and sniffing. Methamphetamine also induced the decrease in levels of its major metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanilic acid (HVA). Both the increase in extracellular levels of dopamine and the induction of dopamine-related behaviors by methamphetamine were significantly suppressed by pretreatment with an intranucleus accumbens injection of a selective ROCK inhibitor Y-27632. In contrast, Y-27632 had no effect on the decrease in levels of DOPAC and HVA induced by methamphetamine. Under these conditions, there were no changes in protein levels of membrane-bound RhoA in the nucleus accumbens following methamphetamine treatment. It is of interest to note that the microinjection of Y-27632 into the nucleus accumbens failed to suppress the increases in extracellular levels of dopamine, DOPAC, and HVA in the nucleus accumbens induced by subcutaneous injection of a prototype of micro -opioid receptor agonist morphine (10 mg/kg). Furthermore, perfusion of a selective blocker of voltage-dependent Na+ channels, tetrodotoxin (TTx) into the rat nucleus accumbens did not affect the increase in extracellular levels of dopamine in the rat nucleus accumbens by methamphetamine, whereas the morphine-induced dopamine elevation was eliminated by this application of TTx. The extracellular level of dopamine in the nucleus accumbens was also increased by perfusion of a selective dopamine re-uptake inhibitor 1-[2-[bis(4-fluorophenyl)methoxy]-4-(3-phenylpropyl)piperazine (GBR-12909) in the nucleus accumbens. This effect was not affected by pretreatment with intranucleus accumbens injection of Y-27632. These findings provide first evidence that Rho/ROCK pathway in the nucleus accumbens may contribute to the increase in extracellular levels of dopamine in the nucleus accumbens evoked by a single subcutaneous injection of methamphetamine. In contrast, this pathway is not essential for the increased level of dopamine in this region induced by morphine, providing further evidence for the different mechanisms of dopamine release by methamphetamine and morphine in rats.
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Affiliation(s)
- Minoru Narita
- Department of Toxicology, School of Pharmacy and Pharmaceutical Science, Hoshi University, Shinagawa-ku, Tokyo, Japan
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17
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Yamaguchi Y, Katoh H, Negishi M. N-terminal short sequences of alpha subunits of the G12 family determine selective coupling to receptors. J Biol Chem 2003; 278:14936-9. [PMID: 12594220 DOI: 10.1074/jbc.m301409200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Galpha subunits of the G(12) family of heterotrimeric G proteins, defined by Galpha(12) and Galpha(13), have many cellular functions in common, such as stress fiber formation and neurite retraction. However, a variety of G protein-coupled receptors appear to couple selectively to Galpha(12) and Galpha(13). For example, thrombin and lysophosphatidic acid (LPA) have been shown to induce stress fiber formation via Galpha(12) and Galpha(13), respectively. We recently showed that active forms of Galpha(12) and Galpha(13) interact with Ser/Thr phosphatase type 5 through its tetratricopeptide repeat domain. Here we developed a novel assay to measure the activities of Galpha(12) and Galpha(13) by using glutathione S-transferase-fused tetratricopeptide repeat domain of Ser/Thr phosphatase type 5, taking advantage of the property that tetratricopeptide repeat domain strongly interacts with active forms of Galpha(12) and Galpha(13). By using this assay, we identified that thrombin and LPA selectively activate Galpha(12) and Galpha(13), respectively. Galpha(12) and Galpha(13) show a high amino acid sequence homology except for their N-terminal short sequences. Then we generated chimeric G proteins Galpha(12N/13C) and Galpha(13N/12C), in which the N-terminal short sequences are replaced by each other, and showed that thrombin and LPA selectively activate Galpha(12N/13C) and Galpha(13N/12C), respectively. Moreover, thrombin and LPA stimulate RhoA activity through Galpha(12) and Galpha(13), respectively, in a Galpha(12) family N-terminal sequence-dependent manner. Thus, N-terminal short sequences of the G(12) family determine the selective couplings of thrombin and LPA receptors to the Galpha(12) family.
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Affiliation(s)
- Yoshiaki Yamaguchi
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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18
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Matsukawa J, Tashiro K, Nagao T, Urushidani T. Role of small GTP-binding proteins and cytoskeleton in gastric acid secretion. Inflammopharmacology 2002. [DOI: 10.1163/156856002321544800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Yamaguchi Y, Katoh H, Mori K, Negishi M. Galpha(12) and Galpha(13) interact with Ser/Thr protein phosphatase type 5 and stimulate its phosphatase activity. Curr Biol 2002; 12:1353-8. [PMID: 12176367 DOI: 10.1016/s0960-9822(02)01034-5] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The Galpha subunits of the G(12) family of heterotrimeric G proteins, defined by Galpha(12) and Galpha(13), are involved in many signaling pathways and diverse cellular functions. In an attempt to elucidate downstream effectors of Galpha(12) for cellular functions, we have performed a yeast two-hybrid screening of a rat brain cDNA library and revealed that Ser/Thr protein phosphatase type 5 (PP5) is a novel effector of Galpha(12) and Galpha(13). PP5 is a newly identified phosphatase and consists of a C-terminal catalytic domain and an N-terminal regulatory tetratricopeptide repeat (TPR) domain [2]. Arachidonic acid was recently shown to activate PP5 phosphatase activity by binding to its TPR domain, however the precise regulatory mechanism of PP5 phosphatase activity is not fully determined. In this study, we show that active forms of Galpha(12) and Galpha(13) specifically interact with PP5 through its TPR domain and activate its phosphatase activity about 2.5-fold. Active forms of Galpha(12) and Galpha(13) also enhance the arachidonic acid-stimulated PP5 phosphatase activity about 2.5-fold. Moreover, we demonstrate that the active form of Galpha(12) translocates PP5 to the cell periphery and colocalizes with PP5. These results propose a new signaling pathway of G(12) family G proteins.
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Affiliation(s)
- Yoshiaki Yamaguchi
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, 606-8502, Kyoto, Japan
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20
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Frantz C, Coppola T, Regazzi R. Involvement of Rho GTPases and their effectors in the secretory process of PC12 cells. Exp Cell Res 2002; 273:119-26. [PMID: 11822867 DOI: 10.1006/excr.2001.5432] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the involvement of Rho GTPases in the secretory process of PC12 cells. Overexpression of wild-type RhoA, Rac1, or Cdc42 did affect exocytosis. In contrast, secretion elicited by depolarizing K(+) concentrations was enhanced by the dominant negative mutants RhoA(N19), Rac1(N17), and Cdc42(N17) and was diminished by the constitutively active mutants RhoA(V14), Rac1(V12), and Cdc42(V12). The inhibition observed in the presence of RhoA(V14) was likely a result of the activation of ROK(alpha), since the catalytic domain of this kinase was able to mimic both the reorganization of the actin cytoskeleton and the decrease in exocytosis induced by the RhoA mutant. Part of the effect of Rac1(V12) may be due to POR1 activation. Thus, overexpression of full-length POR1 diminished K(+)-stimulated exocytosis, and a point mutation in the effector domain of Rac1(V12) that prevents the interaction with POR1 abolished the inhibitory effect of the GTPase. We also searched for the Cdc42(V12) target but overexpression of the Cdc42 effector WASP did not mimic the inhibition of exocytosis observed in cells transfected with the activated GTPase. Our findings indicate that different signaling cascades resulting in the activation of RhoA, Rac1, or Cdc42 can modulate the exocytotic process of neuroendocrine cells.
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Affiliation(s)
- Christian Frantz
- Institut de Biologie Cellulaire et de Morphologie, University of Lausanne, Lausanne, Switzerland
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Vazquez-Martinez R, Shorte SL, Faught WJ, Leaumont DC, Frawley LS, Boockfor FR. Pulsatile exocytosis is functionally associated with GnRH gene expression in immortalized GnRH-expressing cells. Endocrinology 2001; 142:5364-70. [PMID: 11713236 DOI: 10.1210/endo.142.12.8551] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pulsatile release of GnRH is essential for proper reproductive function, but little information is available on the molecular processes underlying this intermittent activity. Recently, GnRH gene expression (GnRH-GE) episodes and exocytotic pulses have been identified separately in individual GnRH-expressing cells, raising the exciting possibility that both activities are linked functionally and are fundamental to the pulsatile process. To explore this, we monitored GnRH-GE (using a GnRH promoter-driven luciferase reporter) and exocytosis (by FM1-43 fluorescence) in the same, living GT1-7 cells. Our results revealed a strong temporal association between exocytotic pulses and GnRH-GE episodes. To determine whether a functional link existed, we blocked one process and evaluated the other. Transcriptional inhibition with actinomycin D had only a modest influence on exocytosis, suggesting that exocytotic pulse activity was not dictated acutely by episodes of gene expression. In contrast, blockage of exocytosis with anti-SNAP-25 (which obstructs secretory granule fusion) abolished GnRH-GE pulse activity, indicating that part of the exocytotic process is responsible for triggering episodes of GnRH-GE. When taken together, our findings suggest that a careful balance is maintained between release and biosynthesis in GT1-7 cells. Such a property may be important in the hypothalamus to ensure that GnRH neurons are in a constant state of readiness to respond to changes in reproductive function.
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Affiliation(s)
- R Vazquez-Martinez
- Laboratory of Molecular Dynamics, Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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22
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Yamaguchi Y, Katoh H, Yasui H, Mori K, Negishi M. RhoA inhibits the nerve growth factor-induced Rac1 activation through Rho-associated kinase-dependent pathway. J Biol Chem 2001; 276:18977-83. [PMID: 11279039 DOI: 10.1074/jbc.m100254200] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Rho family of small GTPases has been shown to be involved in the regulation of neuronal morphology, and Rac and Rho exert antagonistic actions in neurite formation. In this study, we have examined the cross-talk between Rac and Rho in relation to the nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells. NGF induced a rapid activation of Rac1 and suppression of RhoA activity. Constitutively active RhoA, RhoA(V14), or constitutively active Galpha(12)-induced endogenous RhoA activation inhibited the NGF-induced Rac1 activation without any effect on the NGF-induced extracellular signal-regulated kinase activation. Moreover, Y-27632, an inhibitor of Rho-associated kinase, completely abolished the RhoA-induced down-regulation of the NGF-induced Rac1 activation. We also revealed that NGF induced a rapid recruitment of Rac1 to the cell surface protrusion sites and formed filamentous actin-rich protrusions. Activation of RhoA and Rho-associated kinase formed a thick ringlike structure of cortical actin filaments at the cell periphery and then inhibited the NGF-induced recruitment of Rac1 to protrusions. These results indicate that RhoA down-regulates the NGF- induced Rac1 activation through Rho-associated kinase, inhibiting the neurite formation.
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Affiliation(s)
- Y Yamaguchi
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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