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Sazdova I, Hadzi-Petrushev N, Keremidarska-Markova M, Stojchevski R, Sopi R, Shileiko S, Mitrokhin V, Gagov H, Avtanski D, Lubomirov LT, Mladenov M. SIRT-associated attenuation of cellular senescence in vascular wall. Mech Ageing Dev 2024; 220:111943. [PMID: 38762036 DOI: 10.1016/j.mad.2024.111943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/20/2024]
Abstract
This review focuses on the vital function that SIRT1 and other sirtuins play in promoting cellular senescence in vascular smooth muscle cells, which is a key element in the pathogenesis of vascular aging and associated cardiovascular diseases. Vascular aging is a gradual process caused by the accumulation of senescent cells, which results in increased vascular remodeling, stiffness, and diminished angiogenic ability. Such physiological alterations are characterized by a complex interplay of environmental and genetic variables, including oxidative stress and telomere attrition, which affect gene expression patterns and trigger cell growth arrest. SIRT1 has been highlighted for its potential to reduce cellular senescence through modulation of multiple signaling cascades, particularly the endothelial nitric oxide (eNOS)/NO signaling pathway. It also modulates cell cycle through p53 inactivation and suppresses NF-κB mediated expression of adhesive molecules at the vascular level. The study also examines the therapeutic potential of sirtuin modulation in vascular health, identifying SIRT1 and its sirtuin counterparts as potential targets for reducing vascular aging. This study sheds light on the molecular basis of vascular aging and the beneficial effects of sirtuins, paving the way for the development of tailored therapies aimed at enhancing vascular health and prolonging life.
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Affiliation(s)
- Iliyana Sazdova
- Department of Animal and Human Physiology, Faculty of Biology, Sofia University 'St. Kliment Ohridski', Sofia 1504, Bulgaria
| | - Nikola Hadzi-Petrushev
- Institute of Biology, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, Skopje 1000, North Macedonia
| | - Milena Keremidarska-Markova
- Department of Animal and Human Physiology, Faculty of Biology, Sofia University 'St. Kliment Ohridski', Sofia 1504, Bulgaria
| | - Radoslav Stojchevski
- Friedman Diabetes Institute, Lenox Hill Hospital, Northwell Health, 110 E 59th Street, New York, NY 10022, USA
| | - Ramadan Sopi
- Faculty of Medicine, University of Prishtina, Prishtina 10 000, Kosovo
| | - Stanislav Shileiko
- Department of Fundamental and Applied Physiology, Russian States Medical University, Moscow 117997, Russia
| | - Vadim Mitrokhin
- Department of Fundamental and Applied Physiology, Russian States Medical University, Moscow 117997, Russia
| | - Hristo Gagov
- Department of Animal and Human Physiology, Faculty of Biology, Sofia University 'St. Kliment Ohridski', Sofia 1504, Bulgaria
| | - Dimitar Avtanski
- Friedman Diabetes Institute, Lenox Hill Hospital, Northwell Health, 110 E 59th Street, New York, NY 10022, USA
| | - Lubomir T Lubomirov
- Vascular Biology Research Group (RenEVA), Research Institute, Medical University-Varna, Varna, Bulgaria; Institute of Physiology and Pathophysiology, Faculty of Health - School of Medicine, Biomedical Center for Education and Research (ZBAF), Witten/Herdecke University, Witten, Germany
| | - Mitko Mladenov
- Institute of Biology, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, Skopje 1000, North Macedonia; Department of Fundamental and Applied Physiology, Russian States Medical University, Moscow 117997, Russia.
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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)
- Young Soo Han
- Departments of Physiology and Biomedical Engineering and Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
| | - Rishiraj Bandi
- Departments of Physiology and Biomedical Engineering and Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
| | - Matthew J Fogarty
- Departments of Physiology and Biomedical Engineering and Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
| | - Gary C Sieck
- Departments of Physiology and Biomedical Engineering and Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
| | - Frank V Brozovich
- Departments of Physiology and Biomedical Engineering and Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States
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Choo YY, Sakai T, Ikebe R, Jeffers A, Idell S, Tucker TA, Ikebe M. Role of ZIP kinase in development of myofibroblast differentiation from HPMCs. Am J Physiol Lung Cell Mol Physiol 2024; 326:L353-L366. [PMID: 38252666 PMCID: PMC11281797 DOI: 10.1152/ajplung.00251.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 12/14/2023] [Accepted: 01/15/2024] [Indexed: 01/24/2024] Open
Abstract
During the development of pleural fibrosis, pleural mesothelial cells (PMCs) undergo phenotypic switching from differentiated mesothelial cells to mesenchymal cells (MesoMT). Here, we investigated how external stimuli such as TGF-β induce HPMC-derived myofibroblast differentiation to facilitate the development of pleural fibrosis. TGF-β significantly increased di-phosphorylation but not mono-phosphorylation of myosin II regulatory light chain (RLC) in HPMCs. An increase in RLC di-phosphorylation was also found at the pleural layer of our carbon black bleomycin (CBB) pleural fibrosis mouse model, where it showed filamentous localization that coincided with alpha smooth muscle actin (αSMA) in the cells in the pleura. Among the protein kinases that can phosphorylate myosin II RLC, ZIPK (zipper-interacting kinase) protein expression was significantly augmented after TGF-β stimulation. Furthermore, ZIPK gene silencing attenuated RLC di-phosphorylation, suggesting that ZIPK is responsible for di-phosphorylation of myosin II in HPMCs. Although TGF-β significantly increased the expression of ZIP kinase protein, the change in ZIP kinase mRNA was marginal, suggesting a posttranscriptional mechanism for the regulation of ZIP kinase expression by TGF-β. ZIPK gene knockdown (KD) also significantly reduced TGF-β-induced upregulation of αSMA expression. This finding suggests that siZIPK attenuates myofibroblast differentiation of HPMCs. siZIPK diminished TGF-β-induced contractility of HPMCs consistent with siZIPK-induced decrease in the di-phosphorylation of myosin II RLC. The present results implicate ZIPK in the regulation of the contractility of HPMC-derived myofibroblasts, phenotype switching, and myofibroblast differentiation of HPMCs.NEW & NOTEWORTHY Here, we highlight that ZIP kinase is responsible for di-phosphorylation of myosin light chain, which facilitates stress fiber formation and actomyosin-based cell contraction during mesothelial to mesenchymal transition in human pleural mesothelial cells. This transition has a significant impact on tissue remodeling and subsequent stiffness of the pleura. This study provides insight into a new therapeutic strategy for the treatment of pleural fibrosis.
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Affiliation(s)
- Young-Yeon Choo
- Department of Cellular and Molecular Biology, The University of Texas at Tyler Health Science Center, Tyler, Texas, United States
| | - Tsuyoshi Sakai
- Department of Cellular and Molecular Biology, The University of Texas at Tyler Health Science Center, Tyler, Texas, United States
| | - Reiko Ikebe
- Department of Cellular and Molecular Biology, The University of Texas at Tyler Health Science Center, Tyler, Texas, United States
| | - Ann Jeffers
- Department of Cellular and Molecular Biology, The University of Texas at Tyler Health Science Center, Tyler, Texas, United States
| | - Steven Idell
- Department of Cellular and Molecular Biology, The University of Texas at Tyler Health Science Center, Tyler, Texas, United States
| | - Torry A Tucker
- Department of Cellular and Molecular Biology, The University of Texas at Tyler Health Science Center, Tyler, Texas, United States
| | - Mitsuo Ikebe
- Department of Cellular and Molecular Biology, The University of Texas at Tyler Health Science Center, Tyler, Texas, United States
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Wang L, Dong S, Chitano P, Seow CY. Potentiation of active force by cyclic strain in sheep carotid arterial smooth muscle. J Appl Physiol (1985) 2023; 135:1243-1254. [PMID: 37823206 DOI: 10.1152/japplphysiol.00162.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 09/25/2023] [Accepted: 10/09/2023] [Indexed: 10/13/2023] Open
Abstract
The ability to generate force in large arteries is known to be augmented by cyclic strain that mimics the mechanically dynamic in vivo environment associated with blood pressure fluctuation experienced by these arteries. Cyclic strain does not induce a contractile response, like that observed in the myogenic response seen in small arteries, but prompts a substantial increase in the response to electrical stimulation. We coined this phenomenon "force potentiation." Because protein kinase C (PKC) and rho-kinase (ROCK) are known to play a role in increasing contractility of arterial smooth muscle by inhibition of myosin light chain phosphatase, and integrin-link kinase (ILK) is crucial in mechanotransduction, we examined how inhibition of these kinases affected force potentiation in sheep carotid artery. We found that phosphorylation of the regulatory myosin light chain was enhanced by cyclic strain, but the enhancement was observed only in activated, not in relaxed muscle. Inhibition of ROCK diminished force potentiation and active isometric force, likely due to the disinhibition of myosin light chain phosphatase. Inhibition of PKC abolished force potentiation without an effect on active force, suggesting a more exclusive role of PKC (compared with ROCK) in mediating force potentiation. Inhibition of ILK had a similar effect as PKC inhibition, suggesting that ILK may be an upstream kinase for PKC activation by mechanical stimuli. Taken together, the findings suggest that ILK, PKC, and ROCK are important kinases in the signal transduction pathway that mediate the effect of mechanical strain on force potentiation.NEW & NOTEWORTHY When subjected to mechanical strain, smooth muscle from large arteries has the ability to increase its force generation (force potentiation), which could be important in autoregulation of blood pressure. This phenomenon, however, does not involve a myogenic response, such as the one seen in small arteries and arterioles. Our work shows the involvement of ILK, PKC, and ROCK in the signal transduction pathway that mediates the force-potentiating effect of mechanical strain in large arteries.
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Affiliation(s)
- Lu Wang
- Centre for Heart Lung Innovation, St. Paul's Hospital/Providence Health Care, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shoujin Dong
- Department of Respiratory Medicine, Chengdu First People's Hospital, Chengdu, People's Republic of China
| | - Pasquale Chitano
- Centre for Heart Lung Innovation, St. Paul's Hospital/Providence Health Care, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chun Y Seow
- Centre for Heart Lung Innovation, St. Paul's Hospital/Providence Health Care, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Kalra J, Artamonov M, Wang H, Franke A, Markowska Z, Jin L, Derewenda ZS, Ayon RJ, Somlyo A. p90RSK2, a new MLCK mediates contractility in myosin light chain kinase null smooth muscle. Front Physiol 2023; 14:1228488. [PMID: 37781225 PMCID: PMC10533999 DOI: 10.3389/fphys.2023.1228488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 08/24/2023] [Indexed: 10/03/2023] Open
Abstract
Introduction: Phosphorylation of smooth muscle (SM) myosin regulatory light chain (RLC20) is a critical switch leading to SM contraction. The canonical view held that only the short isoform of myosin light chain kinase (MLCK1) catalyzed this reaction. It is now accepted that auxiliary kinases may contribute to vascular SM tone and contractility. We have previously reported that p90 ribosomal S6 kinase (RSK2) functions as such a kinase, in parallel with MLCK1, contributing ∼25% of the maximal myogenic force in resistance arteries. Thus, RSK2 may be instrumental in the regulation of basal vascular tone and blood pressure. Here, we take advantage of a MLCK1 null mouse (mylk1 -/-) to further test our hypothesis that RSK2 can function as an MLCK, playing a significant physiological role in SM contractility. Methods: Using fetal (E14.5-18.5) SM tissues, as embryos die at birth, we investigated the necessity of MLCK for contractility and fetal development and determined the ability of RSK2 kinase to compensate for the lack of MLCK and characterized its signaling pathway in SM. Results and Discussion: Agonists induced contraction and RLC20 phosphorylation in mylk1 -/- SM was attenuated by RSK2 inhibition. The pCa-tension relationships in permeabilized strips of bladder showed no difference in Ca2+ sensitivity in WT vs mylk1 -/- muscles, although the magnitude of force responses was considerably smaller in the absence of MLCK. The magnitude of contractile responses was similar upon addition of GTPγS to activate the RhoA/ROCK pathway or calyculinA to inhibit the myosin phosphatase. The Ca2+-dependent tyrosine kinase, Pyk2, contributed to RSK2-mediated contractility and RLC20 phosphorylation. Proximity-ligation and immunoprecipitation assays demonstrated an association of RSK2, PDK1 and ERK1/2 with MLCK and actin. RSK2, PDK1, ERK1/2 and MLCK formed a signaling complex on the actin filament, positioning them for interaction with adjacent myosin heads. The Ca2+-dependent component reflected the agonist mediated increases in Ca2+, which activated the Pyk2/PDK1/RSK2 signaling cascade. The Ca2+-independent component was through activation of Erk1/2/PDK1/RSK2 leading to direct phosphorylation of RLC20, to increase contraction. Overall, RSK2 signaling constitutes a new third signaling pathway, in addition to the established Ca2+/CaM/MLCK and RhoA/ROCK pathways to regulate SM contractility.
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Affiliation(s)
- Jaspreet Kalra
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
| | - Mykhaylo Artamonov
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Hua Wang
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
- Sentara Martha Jefferson Hospital, Charlottesville, VA, United States
| | - Aaron Franke
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
- Brain Surgery Worldwide, Atlanta, GA, United States
| | - Zaneta Markowska
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
| | - Li Jin
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
- Department of Orthopedics, University of Virginia, Charlottesville, VA, United States
| | - Zygmunt S. Derewenda
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
| | - Ramon J. Ayon
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
| | - Avril Somlyo
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, United States
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Kalra J, Artamonov M, Wang H, Franke A, Markowska Z, Jin L, Derewenda ZS, Ayon R, Somlyo A. p90RSK2, a new MLCK, rescues contractility in myosin light chain kinase null smooth muscle. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541840. [PMID: 37292593 PMCID: PMC10245941 DOI: 10.1101/2023.05.22.541840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background Phosphorylation of smooth muscle (SM) myosin regulatory light chain (RLC 20 ) is a critical switch leading to contraction or cell migration. The canonical view held that the only kinase catalyzing this reaction is the short isoform of myosin light chain kinase (MLCK1). Auxiliary kinases may be involved and play a vital role in blood pressure homeostasis. We have previously reported that p90 ribosomal S6 kinase (RSK2) functions as such a kinase, in parallel with the classical MLCK1, contributing ∼25% of the maximal myogenic force in resistance arteries and regulating blood pressure. Here, we take advantage of a MLCK1 null mouse to further test our hypothesis that RSK2 can function as an MLCK, playing a significant physiological role in SM contractility. Methods Fetal (E14.5-18.5) SM tissues were used as embryos die at birth. We investigated the necessity of MLCK for contractility, cell migration and fetal development and determined the ability of RSK2 kinase to compensate for the lack of MLCK and characterized it's signaling pathway in SM. Results Agonists induced contraction and RLC 20 phosphorylation in mylk1 -/- SM, that was inhibited by RSK2 inhibitors. Embryos developed and cells migrated in the absence of MLCK. The pCa-tension relationships in WT vs mylk1 -/- muscles demonstrated a Ca 2+ -dependency due to the Ca 2+ -dependent tyrosine kinase Pyk2, known to activate PDK1 that phosphorylates and fully activates RSK2. The magnitude of contractile responses was similar upon addition of GTPγS to activate the RhoA/ROCK pathway. The Ca 2+ -independent component was through activation of Erk1/2/PDK1/RSK2 leading to direct phosphorylation of RLC 20 , to increase contraction. RSK2, PDK1, Erk1/2 and MLCK formed a signaling complex on the actin filament, optimally positioning them for interaction with adjacent myosin heads. Conclusions RSK2 signaling constitutes a new third signaling pathway, in addition to the established Ca 2+ /CAM/MLCK and RhoA/ROCK pathways to regulate SM contractility and cell migration.
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Myosin light chain phosphorylation exhibits a gradient across the wall of cerebellar arteries under sustained ex vivo vascular tone. Sci Rep 2023; 13:909. [PMID: 36650375 PMCID: PMC9845333 DOI: 10.1038/s41598-023-28092-3] [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: 06/14/2022] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
Small blood vessel diseases are often associated with impaired regulation of vascular tone. The current understanding of resistance arteries often focuses on how a level of vascular tone is achieved in the acute phase, while less emphasis is placed on mechanisms that maintain vascular tone. In this study, cannulated rat superior cerebellar arteries (SCA) developed spontaneous myogenic tone and showed a marked and sustained constriction in the presence of diluted serum (10%), a stimulus relevant to cerebrovascular disease. Both phosphorylated myosin light chain (MLC-p) and smooth muscle alpha actin (SM-α-actin) aligned with phalloidin-stained actin filaments in the vessel wall, while exhibiting a 'high to low' gradient across the layers of vascular smooth muscle cells (VSMC), peaking in the outer layer. The MLC-p distribution profile shifted towards the adventitia in serum treated vessels, while removal of the serum reversed it. Furthermore, a positive correlation between the MLC-p signal and vessel wall tension was also evident. The gradients of phosphorylated MLC and SM-α-actin are consistent with a spatial regulation of the myosin-actin apparatus in the vessel wall during the maintenance of vascular tone. Further, the changing profiles of MLC-p and SM-α-actin are consistent with SCA vasoconstriction being accompanied by VSMC cytoskeletal reorganization.
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Deletion of Notch3 Impairs Contractility of Renal Resistance Vessels Due to Deficient Ca 2+ Entry. Int J Mol Sci 2022; 23:ijms232416068. [PMID: 36555708 PMCID: PMC9788231 DOI: 10.3390/ijms232416068] [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: 10/19/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Notch3 plays an important role in the differentiation and development of vascular smooth muscle cells. Mice lacking Notch3 show deficient renal autoregulation. The aim of the study was to investigate the mechanisms involved in the Notch3-mediated control of renal vascular response. To this end, renal resistance vessels (afferent arterioles) were isolated from Notch3-/- and wild-type littermates (WT) and stimulated with angiotensin II (ANG II). Contractions and intracellular Ca2+ concentrations were blunted in Notch3-/- vessels. ANG II responses in precapillary muscle arterioles were similar between the WT and Notch3-/- mice, suggesting a focal action of Notch3 in renal vasculature. Abolishing stored Ca2+ with thapsigargin reduced Ca2+ responses in the renal vessels of the two strains, signifying intact intracellular Ca2+ mobilization in Notch3-/-. EGTA (Ca2+ chelating agent), nifedipine (L-type channel-blocker), or mibefradil (T-type channel-blocker) strongly reduced contraction and Ca2+ responses in WT mice but had no effect in Notch3-/- mice, indicating defective Ca2+ entry. Notch3-/- vessels responded normally to KCl-induced depolarization, which activates L-type channels directly. Differential transcriptomic analysis showed a major down-regulation of Cacna1h gene expression, coding for the α1H subunit of the T-type Ca2+ channel, in Notch3-/- vessels. In conclusion, renal resistance vessels from Notch3-/- mice display altered vascular reactivity to ANG II due to deficient Ca2+-entry. Consequently, Notch3 is essential for proper excitation-contraction coupling and vascular-tone regulation in the kidney.
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McDonald PC, Dedhar S. New Perspectives on the Role of Integrin-Linked Kinase (ILK) Signaling in Cancer Metastasis. Cancers (Basel) 2022; 14:cancers14133209. [PMID: 35804980 PMCID: PMC9264971 DOI: 10.3390/cancers14133209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 12/14/2022] Open
Abstract
Simple Summary Today, the vast majority of deaths from cancer are due to cancer metastasis. Metastasis requires that cancer cells escape from the initial tumor, travel through blood vessels, and form new tumors in distant host tissues. Integrin-linked kinase (ILK) is overexpressed by many types of cancer cells and provides both structural and signaling functions that are important for successful metastasis. Here, we discuss recent findings that show how ILK is involved in promoting physical changes important for cell motility and invasion, and how ILK relays signals to other machinery components during metastasis, including interactions with components of the immune system and communication between cancer cells and normal cells, to affect the process of metastasis. We also discuss the contribution of ILK to therapeutic resistance and examine efforts to target ILK for the treatment of metastatic disease. Abstract Cancer metastasis is a major barrier to the long-term survival of cancer patients. In cancer cells, integrin engagement downstream of cell-extracellular matrix (ECM) interactions results in the recruitment of cytoskeletal and signaling molecules to form multi-protein complexes to promote processes critical for metastasis. One of the major functional components of these complexes is Integrin Linked Kinase (ILK). Here, we discuss recent advances in our understanding of the importance of ILK as a signaling effector in processes linked to tumor progression and metastasis. New mechanistic insights as to the role of ILK in cellular plasticity, epithelial mesenchymal transition (EMT), migration, and invasion, including the impact of ILK on the formation of invadopodia, filopodia-like protrusions (FLPs), and Neutrophil Extracellular Trap (NET)-induced motility are highlighted. Recent findings detailing the contribution of ILK to therapeutic resistance and the importance of ILK as a potentially therapeutically tractable vulnerability in both solid tumors and hematologic malignancies are discussed. Indeed, pharmacologic inhibition of ILK activity using specific small molecule inhibitors is effective in curtailing the contribution of ILK to these processes, potentially offering a novel therapeutic avenue for inhibiting critical steps in the metastatic cascade leading to reduced drug resistance and increased therapeutic efficacy.
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Affiliation(s)
- Paul C. McDonald
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada;
| | - Shoukat Dedhar
- Department of Integrative Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 1L3, Canada;
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Correspondence:
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Górska A, Mazur AJ. Integrin-linked kinase (ILK): the known vs. the unknown and perspectives. Cell Mol Life Sci 2022; 79:100. [PMID: 35089438 PMCID: PMC8799556 DOI: 10.1007/s00018-021-04104-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/29/2021] [Accepted: 12/17/2021] [Indexed: 02/08/2023]
Abstract
Integrin-linked kinase (ILK) is a multifunctional molecular actor in cell-matrix interactions, cell adhesion, and anchorage-dependent cell growth. It combines functions of a signal transductor and a scaffold protein through its interaction with integrins, then facilitating further protein recruitment within the ILK-PINCH-Parvin complex. ILK is involved in crucial cellular processes including proliferation, survival, differentiation, migration, invasion, and angiogenesis, which reflects on systemic changes in the kidney, heart, muscle, skin, and vascular system, also during the embryonal development. Dysfunction of ILK underlies the pathogenesis of various diseases, including the pro-oncogenic activity in tumorigenesis. ILK localizes mostly to the cell membrane and remains an important component of focal adhesion. We do know much about ILK but a lot still remains either uncovered or unclear. Although it was initially classified as a serine/threonine-protein kinase, its catalytical activity is now questioned due to structural and functional issues, leaving the exact molecular mechanism of signal transduction by ILK unsolved. While it is known that the three isoforms of ILK vary in length, the presence of crucial domains, and modification sites, most of the research tends to focus on the main isoform of this protein while the issue of functional differences of ILK2 and ILK3 still awaits clarification. The activity of ILK is regulated on the transcriptional, protein, and post-transcriptional levels. The crucial role of phosphorylation and ubiquitylation has been investigated, but the functions of the vast majority of modifications are still unknown. In the light of all those open issues, here we present an extensive literature survey covering a wide spectrum of latest findings as well as a past-to-present view on controversies regarding ILK, finishing with pointing out some open questions to be resolved by further research.
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Affiliation(s)
- Agata Górska
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, ul. Joliot-Curie 14a, 50-383, Wrocław, Poland.
| | - Antonina Joanna Mazur
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, ul. Joliot-Curie 14a, 50-383, Wrocław, Poland.
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Selivanova EK, Gaynullina DK, Tarasova OS. Thyroxine Induces Acute Relaxation of Rat Skeletal Muscle Arteries via Integrin αvβ3, ERK1/2 and Integrin-Linked Kinase. Front Physiol 2021; 12:726354. [PMID: 34594239 PMCID: PMC8477044 DOI: 10.3389/fphys.2021.726354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/23/2021] [Indexed: 11/17/2022] Open
Abstract
Aim: Hyperthyroidism is associated with a decreased peripheral vascular resistance, which could be caused by the vasodilator genomic or non-genomic effects of thyroid hormones (TH). Non-genomic, or acute, effects develop within several minutes and involve a wide tissue-specific spectrum of molecular pathways poorly studied in vasculature. We aimed to investigate the mechanisms of acute effects of TH on rat skeletal muscle arteries. Methods: Sural arteries from male Wistar rats were used for isometric force recording (wire myography) and phosphorylated protein content measurement (Western blotting). Results: Both triiodothyronine (T3) and thyroxine (T4) reduced contractile response of sural arteries to α1-adrenoceptor agonist methoxamine. The effect of T4 was more prominent than T3 and not affected by iopanoic acid, an inhibitor of deiodinase 2. Endothelium denudation abolished the effect of T3, but not T4. Integrin αvβ3 inhibitor tetrac abolished the effect of T4 in endothelium-denuded arteries. T4 weakened methoxamine-induced elevation of phospho-MLC2 (Ser19) content in arterial samples. The effect of T4 in endothelium-denuded arteries was abolished by inhibiting ERK1/2 activation with U0126 as well as by ILK inhibitor Cpd22 but persisted in the presence of Src- or Rho-kinase inhibitors (PP2 and Y27632, respectively). Conclusion: Acute non-genomic relaxation of sural arteries induced by T3 is endothelium-dependent and that induced by T4 is endothelium-independent. The effect of T4 on α1-adrenergic contraction is stronger compared to T3 and involves the suppression of extracellular matrix signaling via integrin αvβ3, ERK1/2 and ILK with subsequent decrease of MLC2 (Ser19) phosphorylation.
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Affiliation(s)
- Ekaterina K Selivanova
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Dina K Gaynullina
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia.,Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Olga S Tarasova
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia.,Laboratory of Exercise Physiology, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
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12
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Li B, Wang X, Wang R, Rutz B, Ciotkowska A, Gratzke C, Herlemann A, Spek A, Tamalunas A, Waidelich R, Stief CG, Hennenberg M. Inhibition of neurogenic and thromboxane A 2 -induced human prostate smooth muscle contraction by the integrin α2β1 inhibitor BTT-3033 and the integrin-linked kinase inhibitor Cpd22. Prostate 2020; 80:831-849. [PMID: 32449814 DOI: 10.1002/pros.23998] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/16/2020] [Accepted: 04/19/2020] [Indexed: 01/23/2023]
Abstract
INTRODUCTION Prostate smooth muscle contraction is critical for etiology and treatment of lower urinary tract symptoms in benign prostatic hyperplasia (BPH). Integrins connect the cytoskeleton to membranes and cells to extracellular matrix, what is essential for force generation in smooth muscle contraction. Integrins are composed of different subunits and may cooperate with integrin-linked kinase (ILK). Here, we examined effects of inhibitors for different integrin heterodimers and ILK on contraction of human prostate tissues. METHODS Prostate tissues were obtained from radical prostatectomy. Integrins and ILK were detected by Western blot, real-time polymerase chain reaction (RT-PCR), and double fluorescence staining. Smooth muscle contractions of prostate strips were studied in an organ bath. Contractions were compared after application of solvent (controls), the ILK inhibitor Cpd22 (N-methyl-3-(1-(4-(piperazin-1-yl)phenyl)-5-(4'-(trifluoromethyl)-[1,1'-biphenyl]-4-yl)-1H-pyrazol-3-yl)propanamide), the integrin α2β1 inhibitor BTT-3033 (1-(4-fluorophenyl)-N-methyl-N-[4[[(phenylamino)carbonyl]amino]phenyl]-1H-pyrazole-4-sulfonamide), or the integrin α4β1/α9β1 inhibitor BOP (N-(benzenesulfonyl)- l-prolyl- l-O-(1-pyrrolidinylcarbonyl)tyrosine sodium salt). RESULTS Western blot analyses of prostate tissues using antibodies raised against integrins α2b, α4, α9, β1, and ILK revealed bands matching the expected sizes of corresponding antigens. Expression of integrins and ILK was confirmed by RT-PCR. Individual variations of expression levels occurred independently from divergent degree of BPH, reflected by different contents of prostate-specific antigen. Double fluorescence staining of prostate sections using antibodies raised against integrins α2 and β1, or against ILK resulted in immunoreactivity colocalizing with calponin, suggesting localization in prostate smooth muscle cells. Electric field stimulation (EFS) induced frequency-dependent contractions, which were inhibited by Cpd22 (3 µM) and BTT-3033 (1 µM) (inhibition around 37% by Cpd22 and 46% by BTT-3033 at 32 Hz). The thromboxane A2 analog U46619-induced concentration-dependent contractions, which were inhibited by Cpd22 and BTT-3033 (around 67% by Cpd22 and 39% by BTT-3033 at 30 µM U46619). Endothelin-1 induced concentration-dependent contractions, which were not affected by Cpd22 or BTT-3033. Noradrenaline and the α1 -adrenergic agonists methoxamine and phenylephrine-induced concentration-dependent contractions, which were not or very slightly inhibited by Cpd22 and BTT-3033. BOP did not change EFS- or agonist-induced contraction. CONCLUSIONS Integrin α2β1 and ILK inhibitors inhibit neurogenic and thromboxane A2 -induced prostate smooth muscle contraction in human BPH. A role for these targets for prostate smooth muscle contraction may appear possible.
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Affiliation(s)
- Bingsheng Li
- Department of Urology, LMU Munich, University Hospital, Munich, Germany
| | - Xiaolong Wang
- Department of Urology, LMU Munich, University Hospital, Munich, Germany
| | - Ruixiao Wang
- Department of Urology, LMU Munich, University Hospital, Munich, Germany
| | - Beata Rutz
- Department of Urology, LMU Munich, University Hospital, Munich, Germany
| | - Anna Ciotkowska
- Department of Urology, LMU Munich, University Hospital, Munich, Germany
| | | | - Annika Herlemann
- Department of Urology, LMU Munich, University Hospital, Munich, Germany
| | - Annabel Spek
- Department of Urology, LMU Munich, University Hospital, Munich, Germany
| | | | | | - Christian G Stief
- Department of Urology, LMU Munich, University Hospital, Munich, Germany
| | - Martin Hennenberg
- Department of Urology, LMU Munich, University Hospital, Munich, Germany
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13
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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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14
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Artamonov MV, Sonkusare SK, Good ME, Momotani K, Eto M, Isakson BE, Le TH, Cope EL, Derewenda ZS, Derewenda U, Somlyo AV. RSK2 contributes to myogenic vasoconstriction of resistance arteries by activating smooth muscle myosin and the Na +/H + exchanger. Sci Signal 2018; 11:11/554/eaar3924. [PMID: 30377223 DOI: 10.1126/scisignal.aar3924] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Smooth muscle contraction is triggered when Ca2+/calmodulin-dependent myosin light chain kinase (MLCK) phosphorylates the regulatory light chain of myosin (RLC20). However, blood vessels from Mlck-deficient mouse embryos retain the ability to contract, suggesting the existence of additional regulatory mechanisms. We showed that the p90 ribosomal S6 kinase 2 (RSK2) also phosphorylated RLC20 to promote smooth muscle contractility. Active, phosphorylated RSK2 was present in mouse resistance arteries under normal basal tone, and phosphorylation of RSK2 increased with myogenic vasoconstriction or agonist stimulation. Resistance arteries from Rsk2-deficient mice were dilated and showed reduced myogenic tone and RLC20 phosphorylation. RSK2 phosphorylated Ser19 in RLC in vitro. In addition, RSK2 phosphorylated an activating site in the Na+/H+ exchanger (NHE-1), resulting in cytosolic alkalinization and an increase in intracellular Ca2+ that promotes vasoconstriction. NHE-1 activity increased upon myogenic constriction, and the increase in intracellular pH was suppressed in Rsk2-deficient mice. In pressured arteries, RSK2-dependent activation of NHE-1 was associated with increased intracellular Ca2+ transients, which would be expected to increase MLCK activity, thereby contributing to basal tone and myogenic responses. Accordingly, Rsk2-deficient mice had lower blood pressure than normal littermates. Thus, RSK2 mediates a procontractile signaling pathway that contributes to the regulation of basal vascular tone, myogenic vasoconstriction, and blood pressure and may be a potential therapeutic target in smooth muscle contractility disorders.
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Affiliation(s)
- Mykhaylo V Artamonov
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Swapnil K Sonkusare
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Miranda E Good
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Ko Momotani
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.,Faculty of Pharmaceutical Sciences, Sanyo-Onoda City University, 1-1-1 Daigaku-dori, Sanyo-Onoda-shi, Yamaguchi 756-0884, Japan
| | - Masumi Eto
- Department of Molecular Physiology and Biophysics, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, USA.,Faculty of Veterinary Medicine, Okayama University of Science, 1-13 Ikoinooka-oka, Imabari, Ehime 794-0085, Japan
| | - Brant E Isakson
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Thu H Le
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.,Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Eric L Cope
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Zygmunt S Derewenda
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Urszula Derewenda
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Avril V Somlyo
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.
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15
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Chang AN, Gao N, Liu Z, Huang J, Nairn AC, Kamm KE, Stull JT. The dominant protein phosphatase PP1c isoform in smooth muscle cells, PP1cβ, is essential for smooth muscle contraction. J Biol Chem 2018; 293:16677-16686. [PMID: 30185619 DOI: 10.1074/jbc.ra118.003083] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 08/30/2018] [Indexed: 12/29/2022] Open
Abstract
Contractile force development of smooth muscle is controlled by balanced kinase and phosphatase activities toward the myosin regulatory light chain (RLC). Numerous biochemical and pharmacological studies have investigated the specificity and regulatory activity of smooth muscle myosin light-chain phosphatase (MLCP) bound to myosin filaments and comprised of the regulatory myosin phosphatase target subunit 1 (MYPT1) and catalytic protein phosphatase 1cβ (PP1cβ) subunits. Recent physiological and biochemical evidence obtained with smooth muscle tissues from a conditional MYPT1 knockout suggests that a soluble, MYPT1-unbound form of PP1cβ may additionally contribute to myosin RLC dephosphorylation and relaxation of smooth muscle. Using a combination of isoelectric focusing and isoform-specific immunoblotting, we found here that more than 90% of the total PP1c in mouse smooth muscles is the β isoform. Moreover, conditional knockout of PP1cα or PP1cγ in adult smooth muscles did not result in an apparent phenotype in mice up to 6 months of age and did not affect smooth muscle contractions ex vivo In contrast, smooth muscle-specific conditional PP1cβ knockout decreased contractile force development in bladder, ileal, and aortic tissues and reduced mouse survival. Bladder smooth muscle tissue from WT mice was selectively permeabilized to remove soluble PP1cβ to measure contributions of total (α-toxin treatment) and myosin-bound (Triton X-100 treatment) phosphatase activities toward phosphorylated RLC in myofilaments. Triton X-100 reduced PP1cβ content by 60% and the rate of RLC dephosphorylation by 2-fold. These results are consistent with the selective dephosphorylation of RLC by both MYPT1-bound and -unbound PP1cβ forms in smooth muscle.
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Affiliation(s)
- Audrey N Chang
- From the Departments of Physiology and .,Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9040 and
| | - Ning Gao
- From the Departments of Physiology and
| | | | | | - Angus C Nairn
- the Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut 06508
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16
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Chappellaz M, Segboer H, Ulke-Lemée A, Sutherland C, Chen HM, MacDonald JA. Quantitation of myosin regulatory light chain phosphorylation in biological samples with multiple reaction monitoring mass spectrometry. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:608-616. [PMID: 29567090 DOI: 10.1016/j.bbapap.2018.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 02/22/2018] [Accepted: 03/16/2018] [Indexed: 10/17/2022]
Abstract
The 20-kDa regulatory light chain of myosin II plays an important role in regulating smooth muscle contractile force. LC20 is phosphorylated canonically by myosin light chain kinase in a Ca2+/calmodulin-dependent manner at S19. The diphosphorylation of LC20 at T18 and S19 has been observed in smooth muscle tissues. Given that the phosphorylation of LC20 is positively correlated with tension development, the molar stoichiometry of LC20 phosphorylation is commonly profiled as a measure of smooth muscle contractility. Herein, we describe a novel multiple reaction monitoring (MRM)-mass spectrometry (MS) approach for the quantification of LC20 phosphorylation at T18 and S19. Unique precursor as well as y- and b-ion transitions were identified for unphosphorylated LC20-(TS), monophosphorylated LC20-(TpS) and diphosphorylated LC20-(pTpS) peptides. The MRM-MS assay could accurately define molar phosphorylation stoichiometries of S19 and T18 over a broad range (i.e., 0-2 mol P/mol LC20). Correlations of the results for two quantification techniques indicate that the MRM-MS assay performs equally to Phos-tag SDS-PAGE for the determination of LC20 phosphorylation stoichiometry in arterial tissue samples. The MRM-MS technique provides a robust alternative to antibody-based detection systems for the quantification of LC20 phosphorylation.
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Affiliation(s)
- Mona Chappellaz
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4Z6, Canada
| | - Hayden Segboer
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4Z6, Canada
| | - Annegret Ulke-Lemée
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4Z6, Canada
| | - Cindy Sutherland
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4Z6, Canada
| | - Huey-Miin Chen
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4Z6, Canada
| | - Justin A MacDonald
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4Z6, Canada.
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17
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Huhtinen A, Hongisto V, Laiho A, Löyttyniemi E, Pijnenburg D, Scheinin M. Gene expression profiles and signaling mechanisms in α 2B-adrenoceptor-evoked proliferation of vascular smooth muscle cells. BMC SYSTEMS BIOLOGY 2017; 11:65. [PMID: 28659168 PMCID: PMC5490158 DOI: 10.1186/s12918-017-0439-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 06/09/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND α2-adrenoceptors are important regulators of vascular tone and blood pressure. Regulation of cell proliferation is a less well investigated consequence of α2-adrenoceptor activation. We have previously shown that α2B-adrenoceptor activation stimulates proliferation of vascular smooth muscle cells (VSMCs). This may be important for blood vessel development and plasticity and for the pathology and therapeutics of cardiovascular disorders. The underlying cellular mechanisms have remained mostly unknown. This study explored pathways of regulation of gene expression and intracellular signaling related to α2B-adrenoceptor-evoked VSMC proliferation. RESULTS The cellular mechanisms and signaling pathways of α2B-adrenoceptor-evoked proliferation of VSMCs are complex and include redundancy. Functional enrichment analysis and pathway analysis identified differentially expressed genes associated with α2B-adrenoceptor-regulated VSMC proliferation. They included the upregulated genes Egr1, F3, Ptgs2 and Serpine1 and the downregulated genes Cx3cl1, Cav1, Rhoa, Nppb and Prrx1. The most highly upregulated gene, Lypd8, represents a novel finding in the VSMC context. Inhibitor library screening and kinase activity profiling were applied to identify kinases in the involved signaling pathways. Putative upstream kinases identified by two different screens included PKC, Raf-1, Src, the MAP kinases p38 and JNK and the receptor tyrosine kinases EGFR and HGF/HGFR. As a novel finding, the Src family kinase Lyn was also identified as a putative upstream kinase. CONCLUSIONS α2B-adrenoceptors may mediate their pro-proliferative effects in VSMCs by promoting the activity of bFGF and PDGF and the growth factor receptors EGFR, HGFR and VEGFR-1/2. The Src family kinase Lyn was also identified as a putative upstream kinase. Lyn is known to be expressed in VSMCs and has been identified as an important regulator of GPCR trafficking and GPCR effects on cell proliferation. Identified Ser/Thr kinases included several PKC isoforms and the β-adrenoceptor kinases 1 and 2. Cross-talk between the signaling mechanisms involved in α2B-adrenoceptor-evoked VSMC proliferation thus appears to involve PKC activation, subsequent changes in gene expression, transactivation of EGFR, and modulation of kinase activities and growth factor-mediated signaling. While many of the identified individual signals were relatively small in terms of effect size, many of them were validated by combining pathway analysis and our integrated screening approach.
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Affiliation(s)
- Anna Huhtinen
- Department of Pharmacology, Drug Development and Therapeutics, Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
- Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
| | - Vesa Hongisto
- Toxicology Division, Misvik Biology Oy, Turku, Finland
| | - Asta Laiho
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Eliisa Löyttyniemi
- Department of Biostatistics, Department of Clinical Medicine, University of Turku, Turku, Finland
| | - Dirk Pijnenburg
- PamGene International BV, Wolvenhoek 10, 5211HH s’Hertogenbosch, The Netherlands
| | - Mika Scheinin
- Department of Pharmacology, Drug Development and Therapeutics, Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
- Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
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18
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Al-Ghabkari A, Deng JT, McDonald PC, Dedhar S, Alshehri M, Walsh MP, MacDonald JA. A novel inhibitory effect of oxazol-5-one compounds on ROCKII signaling in human coronary artery vascular smooth muscle cells. Sci Rep 2016; 6:32118. [PMID: 27573465 PMCID: PMC5004178 DOI: 10.1038/srep32118] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/02/2016] [Indexed: 12/27/2022] Open
Abstract
The selectivity of (4Z)-2-(4-chloro-3-nitrophenyl)-4-(pyridin-3-ylmethylidene)-1,3-oxazol-5-one (DI) for zipper-interacting protein kinase (ZIPK) was previously described by in silico computational modeling, screening a large panel of kinases, and determining the inhibition efficacy. Our assessment of DI revealed another target, the Rho-associated coiled-coil-containing protein kinase 2 (ROCKII). In vitro studies showed DI to be a competitive inhibitor of ROCKII (Ki, 132 nM with respect to ATP). This finding was supported by in silico molecular surface docking of DI with the ROCKII ATP-binding pocket. Time course analysis of myosin regulatory light chain (LC20) phosphorylation catalyzed by ROCKII in vitro revealed a significant decrease upon treatment with DI. ROCKII signaling was investigated in situ in human coronary artery vascular smooth muscle cells (CASMCs). ROCKII down-regulation using siRNA revealed several potential substrates involved in smooth muscle contraction (e.g., LC20, Par-4, MYPT1) and actin cytoskeletal dynamics (cofilin). The application of DI to CASMCs attenuated LC20, Par-4, LIMK, and cofilin phosphorylations. Notably, cofilin phosphorylation was not significantly decreased with a novel ZIPK selective inhibitor (HS-38). In addition, CASMCs treated with DI underwent cytoskeletal changes that were associated with diminution of cofilin phosphorylation. We conclude that DI is not selective for ZIPK and is a potent inhibitor of ROCKII.
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Affiliation(s)
- Abdulhameed Al-Ghabkari
- Department of Biochemistry &Molecular Biology, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Jing-Ti Deng
- Department of Biochemistry &Molecular Biology, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Paul C McDonald
- Department of Integrative Oncology, BC Cancer Research Centre, 675 West 10th Ave, Vancouver, BC, V5Z 1L3, Canada
| | - Shoukat Dedhar
- Department of Integrative Oncology, BC Cancer Research Centre, 675 West 10th Ave, Vancouver, BC, V5Z 1L3, Canada
| | - Mana Alshehri
- Department of Biochemistry &Molecular Biology, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Michael P Walsh
- Department of Biochemistry &Molecular Biology, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Justin A MacDonald
- Department of Biochemistry &Molecular Biology, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
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19
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Stark CKJ, Tarkia M, Kentala R, Malmberg M, Vähäsilta T, Savo M, Hynninen VV, Helenius M, Ruohonen S, Jalkanen J, Taimen P, Alastalo TP, Saraste A, Knuuti J, Savunen T, Koskenvuo J. Systemic Dosing of Thymosin Beta 4 before and after Ischemia Does Not Attenuate Global Myocardial Ischemia-Reperfusion Injury in Pigs. Front Pharmacol 2016; 7:115. [PMID: 27199757 PMCID: PMC4853610 DOI: 10.3389/fphar.2016.00115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 04/18/2016] [Indexed: 12/30/2022] Open
Abstract
The use of cardiopulmonary bypass (CPB) and aortic cross-clamping causes myocardial ischemia-reperfusion injury (I-RI) and can lead to reduced postoperative cardiac function. We investigated whether this injury could be attenuated by thymosin beta 4 (TB4), a peptide which has showed cardioprotective effects. Pigs received either TB4 or vehicle and underwent CPB and aortic cross-clamping for 60 min with cold intermittent blood-cardioplegia and were then followed for 30 h. Myocardial function and blood flow was studied by cardiac magnetic resonance and PET imaging. Tissue and plasma samples were analyzed to determine the amount of cardiomyocyte necrosis and apoptosis as well as pharmacokinetics of the peptide. In vitro studies were performed to assess its influence on blood coagulation and vasomotor tone. Serum levels of the peptide were increased after administration compared to control samples. TB4 did not decrease the amount of cell death. Cardiac function and global myocardial blood flow was similar between the study groups. At high doses a vasoconstrictor effect on mesentery arteries and a vasodilator effect on coronary arteries was observed and blood clot firmness was reduced when tested in the presence of an antiplatelet agent. Despite promising results in previous trials the cardioprotective effect of TB4 was not demonstrated in this model for global myocardial I-RI.
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Affiliation(s)
- Christoffer K-J Stark
- Research Center of Applied and Preventive Cardiovascular Medicine, University of TurkuTurku, Finland; Heart Center, Turku University Hospital and University of TurkuTurku, Finland
| | - Miikka Tarkia
- Turku PET Centre, Turku University Hospital and University of Turku Turku, Finland
| | - Rasmus Kentala
- Research Center of Applied and Preventive Cardiovascular Medicine, University of Turku Turku, Finland
| | - Markus Malmberg
- Heart Center, Turku University Hospital and University of Turku Turku, Finland
| | - Tommi Vähäsilta
- Research Center of Applied and Preventive Cardiovascular Medicine, University of TurkuTurku, Finland; Heart Center, Turku University Hospital and University of TurkuTurku, Finland
| | - Matti Savo
- Research Center of Applied and Preventive Cardiovascular Medicine, University of Turku Turku, Finland
| | - Ville-Veikko Hynninen
- Department of Anesthesiology, Intensive Care, Emergency Care and Pain Medicine, Turku University Hospital Turku, Finland
| | - Mikko Helenius
- Children's Hospital, Pediatric Cardiology, Helsinki University Hospital Helsinki, Finland
| | - Saku Ruohonen
- Research Center of Applied and Preventive Cardiovascular Medicine, University of Turku Turku, Finland
| | - Juho Jalkanen
- Department of Vascular Surgery, Turku University Hospital and University of Turku Turku, Finland
| | - Pekka Taimen
- Department of Pathology, Turku University Hospital and University of Turku Turku, Finland
| | - Tero-Pekka Alastalo
- Children's Hospital, Pediatric Cardiology, Helsinki University Hospital Helsinki, Finland
| | - Antti Saraste
- Turku PET Centre, Turku University Hospital and University of Turku Turku, Finland
| | - Juhani Knuuti
- Turku PET Centre, Turku University Hospital and University of Turku Turku, Finland
| | - Timo Savunen
- Research Center of Applied and Preventive Cardiovascular Medicine, University of Turku Turku, Finland
| | - Juha Koskenvuo
- Research Center of Applied and Preventive Cardiovascular Medicine, University of Turku Turku, Finland
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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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21
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Hirano M, Hirano K. Myosin di-phosphorylation and peripheral actin bundle formation as initial events during endothelial barrier disruption. Sci Rep 2016; 6:20989. [PMID: 26863988 PMCID: PMC4750094 DOI: 10.1038/srep20989] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 01/14/2016] [Indexed: 11/09/2022] Open
Abstract
The phosphorylation of the 20-kD myosin light chain (MLC) and actin filament formation play a key role in endothelial barrier disruption. MLC is either mono- or di-phosphorylated (pMLC and ppMLC) at T18 or S19. The present study investigated whether there are any distinct roles of pMLC and ppMLC in barrier disruption induced by thrombin. Thrombin induced a modest bi-phasic increase in pMLC and a robust mono-phasic increase in ppMLC. pMLC localized in the perinuclear cytoplasm during the initial phase, while ppMLC localized in the cell periphery, where actin bundles were formed. Later, the actin bundles were rearranged into stress fibers, where pMLC co-localized. Rho-kinase inhibitors inhibited thrombin-induced barrier disruption and peripheral localization of ppMLC and actin bundles. The double, but not single, mutation of phosphorylation sites abolished the formation of peripheral actin bundles and the barrier disruption, indicating that mono-phosphorylation of MLC at either T18 or S19 is functionally sufficient for barrier disruption. Namely, the peripheral localization, but not the degree of phosphorylation, is suggested to be essential for the functional effect of ppMLC. These results suggest that MLC phosphorylation and actin bundle formation in cell periphery are initial events during barrier disruption.
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Affiliation(s)
- Mayumi Hirano
- Department of Molecular Cardiology, Research Institute of Angiocardiology, Graduate School of Medical Sciences, Kyushu University
| | - Katsuya Hirano
- Department of Cardiovascular Physiology, Faculty of Medicine, Kagawa University
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22
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Shirley LA, McCarty S, Yang MC, Saji M, Zhang X, Phay J, Ringel MD, Chen CS. Integrin-linked kinase affects signaling pathways and migration in thyroid cancer cells and is a potential therapeutic target. Surgery 2015; 159:163-70. [PMID: 26549818 DOI: 10.1016/j.surg.2015.10.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 09/22/2015] [Accepted: 10/14/2015] [Indexed: 02/08/2023]
Abstract
BACKGROUND Integrin-linked kinase (ILK) is a serine-threonine kinase that regulates interactions between the cell and the extracellular matrix. In many cancers, overexpression of ILK leads to increased cell proliferation, motility, and invasion. We hypothesized that ILK functions as a regulator of viability and migration in thyroid cancer cells. METHODS Eleven human thyroid cancer cell lines were screened for ILK protein expression. The cell lines with the greatest expression were treated with either ILK small interfering RNA (siRNA) or a novel ILK inhibitor, T315, and the effects were evaluated via Western blot and migration assay. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assays were performed to assess cell viability. RESULTS siRNA against ILK decreased phosphorylation of downstream effectors Akt and MLC, as well as decreased migration. Treatment with T315 showed a dose-related decrease in both Akt and MLC phosphorylation, as well as decreased migration. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assays showed T315 to have an half maximal inhibitory concentration of less than 1 μM in cell lines with high ILK expression. CONCLUSION ILK is expressed differentially in thyroid cancer cell lines. Both ILK siRNA and T315 inhibit motility of thyroid cancer cell lines, and T315 is shown to be cytotoxic at low concentrations. Altogether, our study suggests that ILK may represent an important kinase in aggressive thyroid cancers.
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Affiliation(s)
- Lawrence A Shirley
- Division of Surgical Oncology, The Ohio State University Wexner Medical Center, Columbus, OH.
| | - Samantha McCarty
- Division of Surgical Oncology, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Ming-Chen Yang
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH
| | - Motoyasu Saji
- Division of Endocrinology, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Xiaoli Zhang
- Center for Biostatistics, The Ohio State University Wexner Medical Center, Columbus, OH
| | - John Phay
- Division of Surgical Oncology, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Matthew D Ringel
- Division of Endocrinology, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Ching-Shih Chen
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH
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MacDonald JA, Sutherland C, Carlson DA, Bhaidani S, Al-Ghabkari A, Swärd K, Haystead TAJ, Walsh MP. A Small Molecule Pyrazolo[3,4-d]Pyrimidinone Inhibitor of Zipper-Interacting Protein Kinase Suppresses Calcium Sensitization of Vascular Smooth Muscle. Mol Pharmacol 2015; 89:105-17. [DOI: 10.1124/mol.115.100529] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/09/2015] [Indexed: 11/22/2022] Open
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24
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Yoon SH, Ramalingam M, Kim SJ. Insulin stimulates integrin-linked kinase in UMR-106 cells: potential role of heparan sulfate on syndecan-1. J Recept Signal Transduct Res 2015; 35:613-7. [DOI: 10.3109/10799893.2015.1034369] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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25
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Abd-Elrahman KS, Walsh MP, Cole WC. Abnormal Rho-associated kinase activity contributes to the dysfunctional myogenic response of cerebral arteries in type 2 diabetes. Can J Physiol Pharmacol 2015; 93:177-84. [PMID: 25660561 DOI: 10.1139/cjpp-2014-0437] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The structural and functional integrity of the brain, and therefore, cognition, are critically dependent on the appropriate control of blood flow within the cerebral circulation. Inadequate flow leads to ischemia, whereas excessive flow causes small vessel rupture and (or) blood-brain-barrier disruption. Cerebral blood flow is controlled through the interplay of several physiological mechanisms that regulate the contractile state of vascular smooth muscle cells (VSMCs) within the walls of cerebral resistance arteries and arterioles. The myogenic response of cerebral VSMCs is a key mechanism that is responsible for maintaining constant blood flow during variations in systemic pressure, i.e., flow autoregulation. Inappropriate myogenic control of cerebral blood flow is associated with, and prognostic of, neurological deterioration and poor outcome in patients with several conditions, including type 2 diabetes. Here, we review recent advances in our understanding of the role of inappropriate Rho-associated kinase activity as a cause of impaired myogenic regulation of cerebral arterial diameter in type 2 diabetes.
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Affiliation(s)
- Khaled S Abd-Elrahman
- The Smooth Muscle Research Group, Libin Cardiovascular Institute, Hotchkiss Brain Institute, and the Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
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26
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Takeya K, Wang X, Kathol I, Loutzenhiser K, Loutzenhiser R, Walsh MP. Endothelin-1, but not angiotensin II, induces afferent arteriolar myosin diphosphorylation as a potential contributor to prolonged vasoconstriction. Kidney Int 2014; 87:370-81. [PMID: 25140913 DOI: 10.1038/ki.2014.284] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 06/12/2014] [Accepted: 07/10/2014] [Indexed: 11/09/2022]
Abstract
Bolus administration of endothelin-1 elicits long-lasting renal afferent arteriolar vasoconstriction, in contrast to transient constriction induced by angiotensin II. Vasoconstriction is generally evoked by myosin regulatory light chain (LC20) phosphorylation at Ser19 by myosin light chain kinase (MLCK), which is enhanced by Rho-associated kinase (ROCK)-mediated inhibition of myosin light chain phosphatase (MLCP). LC20 can be diphosphorylated at Ser19 and Thr18, resulting in reduced rates of dephosphorylation and relaxation. Here we tested whether LC20 diphosphorylation contributes to sustained endothelin-1 but not transient angiotensin II-induced vasoconstriction. Endothelin-1 treatment of isolated arterioles elicited a concentration- and time-dependent increase in LC20 diphosphorylation at Thr18 and Ser19. Inhibition of MLCK or ROCK reduced endothelin-1-evoked LC20 mono- and diphosphorylation. Pretreatment with an ETB but not an ETA receptor antagonist abolished LC20 diphosphorylation, and an ETB receptor agonist induced LC20 diphosphorylation. In contrast, angiotensin II caused phosphorylation exclusively at Ser19. Thus, endothelin-1 and angiotensin II induce afferent arteriolar constriction via LC20 phosphorylation at Ser19 due to calcium activation of MLCK and ROCK-mediated inhibition of MLCP. Endothelin-1, but not angiotensin II, induces phosphorylation of LC20 at Thr18. This could contribute to the prolonged vasoconstrictor response to endothelin-1.
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Affiliation(s)
- Kosuke Takeya
- 1] Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada [2] Smooth Muscle Research Group and Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Xuemei Wang
- Smooth Muscle Research Group and Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Iris Kathol
- 1] Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada [2] Smooth Muscle Research Group and Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Kathy Loutzenhiser
- Smooth Muscle Research Group and Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Rodger Loutzenhiser
- Smooth Muscle Research Group and Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Michael P Walsh
- Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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27
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Rho kinase acts as a downstream molecule to participate in protein kinase Cε regulation of vascular reactivity after hemorrhagic shock in rats. Shock 2014; 42:239-45. [PMID: 24827390 DOI: 10.1097/shk.0000000000000199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Our previous study demonstrated that Rho kinase and protein kinase C (PKC) played important parts in the regulation of vascular reactivity after shock. Using superior mesenteric arteries (SMAs) from hemorrhagic shock rats and hypoxia-treated vascular smooth muscle cells (VSMCs), relationship of PKCε regulation of vascular reactivity to Rho kinase, as well as the signal transduction after shock, was investigated. The results showed that inhibition of Rho kinase with the Rho kinase-specific inhibitor Y-27632 antagonized the PKCε-specific agonist carbachol and highly expressed PKCε-induced increase of vascular reactivity in SMAs and VSMCs, whereas inhibition of PKCε with its specific inhibitory peptide did not antagonize the Rho kinase agonist (U-46619)-induced increase of vascular reactivity in SMAs and VSMCs. Activation of PKCε or highly expressed PKCε upregulated the activity of Rho kinase and the phosphorylation of PKC-dependent phosphatase inhibitor 17 (CPI-17), zipper interacting protein kinase (ZIPK), and integrin-linked kinase (ILK), whereas activation of Rho kinase increased only CPI-17 phosphorylation. The specific neutralization antibodies of ZIPK and ILK antagonized PKCε-induced increases in the activity of Rho kinase, but CPI-17 neutralization antibody did not antagonize this effect. These results suggested that Rho kinase takes part in the regulation of PKCε on vascular reactivity after shock. Rho kinase is downstream of PKCε. Protein kinase Cε activates Rho kinase via ZIPK and ILK; CPI-17 is downstream of Rho kinase.
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28
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Aguilar HN, Tracey CN, Zielnik B, Mitchell BF. Rho-kinase mediates diphosphorylation of myosin regulatory light chain in cultured uterine, but not vascular smooth muscle cells. J Cell Mol Med 2014; 16:2978-89. [PMID: 22947248 PMCID: PMC4393726 DOI: 10.1111/j.1582-4934.2012.01625.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 08/09/2012] [Indexed: 11/27/2022] Open
Abstract
Phosphorylation of myosin regulatory light chain (RLC) triggers contraction in smooth muscle myocytes. Dephosphorylation of phosphorylated RLC (pRLC) is mediated by myosin RLC phosphatase (MLCP), which is negatively regulated by rho-associated kinase (ROK). We have compared basal and stimulated concentrations of pRLC in myocytes from human coronary artery (hVM), which has a tonic contractile pattern to myocytes from human uterus (hUM), which has a phasic contractile pattern. Our studies reveal fundamental differences between hVM and hUM regarding the mechanisms regulating phosphorylation RLC. Whereas hVM responded to stimulation by phosphorylation of RLC at S19, hUM responded by forming diphosphorylated RLC (at T18 and S19; ppRLC), which, compared to pRLC, causes two to threefold greater activation of myosin ATPase that provides energy to power the contraction. Importantly, the conversion of pRLC to ppRLC is mediated by ROK. In hUM, MLCP has high activity for ppRLC and this is inhibited by ROK through phosphorylation of the substrate targeting subunit (MYPT1) at T853. Inhibitors of ROK significantly reduce contractility in both hVM and hUM. We demonstrated that inhibition of ppRLC in phasic myocytes (hUM) is 100-fold more sensitive to ROK inhibitors than is pRLC in tonic myocytes (hVM). We speculate that these differences in phosphorylation of RLC might reflect evolution of different contractile patterns to perform distinct physiological functions. Furthermore, our data suggest that low concentrations of ROK inhibitors might inhibit uterine contractions with minimal effects on vascular tone, thus posing a novel strategy for prevention or treatment of conditions such as preterm birth.
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Affiliation(s)
- Hector N Aguilar
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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29
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Cheng Q, Sun Z, Meininger G, Almasri M. PDMS Elastic Micropost Arrays for Studying Vascular Smooth Muscle Cells. SENSORS AND ACTUATORS. B, CHEMICAL 2013; 188:1055-1063. [PMID: 26451074 PMCID: PMC4594632 DOI: 10.1016/j.snb.2013.08.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This paper describes the design, modeling, fabrication and characterization of a micromachined array of high-density 3-dimensional microposts (100×100) made of flexible material (silicone elastomers) for use to measure quantitatively the cellular traction force and contractile events in isolated vascular smooth muscle cells (VSMCs). The micropost array was fabricated with diameters ranged from 3 to 10 μm, with edge to edge spacing of 5, 7 and 10 μm, and with a height to diameter aspect ratio up to 10. VSMCs exerted larger basal traction forces when they were grown on stiffer micropost arrays. These basal traction forces were 80% larger in control VSMCs than in VSMCs in which integrin linked kinase (ILK) was knocked down using shRNA. The addition of Angiotensin II (ANGII) led to VSMC contraction as evidenced by an increased traction force exerted on the microposts under the cell. This ANGII induced contractile response and change in traction force on the microposts was not observed in VSMCs lacking ILK. Following treatment of VSMCs with Cytochalasin D to depolymerize the actin cytoskeleton, the VSMCs exhibited relaxation that was apparent as a significant reduction in the measured traction force exerted on microposts under the cell. Overall, this study demonstrates the usefulness of micropost arrays for study of the contractile responsiveness of VSMC and the results indicate that ILK plays a critical role in the signaling pathways leading to the generation of substrate traction force in VSMC.
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Affiliation(s)
- Qi Cheng
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO 65211 USA
| | - Zhe Sun
- Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65211 USA
| | - Gerald Meininger
- Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65211 USA
| | - Mahmoud Almasri
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO 65211 USA
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30
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Mita M, Tanaka H, Yanagihara H, Nakagawa JI, Hishinuma S, Sutherland C, Walsh MP, Shoji M. Membrane depolarization-induced RhoA/Rho-associated kinase activation and sustained contraction of rat caudal arterial smooth muscle involves genistein-sensitive tyrosine phosphorylation. J Smooth Muscle Res 2013; 49:26-45. [PMID: 24133693 PMCID: PMC5137315 DOI: 10.1540/jsmr.49.26] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Rho-associated kinase (ROK) activation plays an important role in K+-induced
contraction of rat caudal arterial smooth muscle (Mita et al., Biochem J. 2002; 364:
431–40). The present study investigated a potential role for tyrosine kinase activity in
K+-induced RhoA activation and contraction. The non-selective tyrosine kinase
inhibitor genistein, but not the src family tyrosine kinase inhibitor PP2, inhibited
K+-induced sustained contraction (IC50 = 11.3 ± 2.4 µM). Genistein
(10 µM) inhibited the K+-induced increase in myosin light chain
(LC20) phosphorylation without affecting the Ca2+ transient. The
tyrosine phosphatase inhibitor vanadate induced contraction that was reversed by genistein
(IC50 = 6.5 ± 2.3 µM) and the ROK inhibitor Y-27632 (IC50 = 0.27 ±
0.04 µM). Vanadate also increased LC20 phosphorylation in a genistein- and
Y-27632-dependent manner. K+ stimulation induced translocation of RhoA to the
membrane, which was inhibited by genistein. Phosphorylation of MYPT1 (myosin-targeting
subunit of myosin light chain phosphatase) was significantly increased at Thr855 and
Thr697 by K+ stimulation in a genistein- and Y-27632-sensitive manner. Finally,
K+ stimulation induced genistein-sensitive tyrosine phosphorylation of
proteins of ∼55, 70 and 113 kDa. We conclude that a genistein-sensitive tyrosine kinase,
activated by the membrane depolarization-induced increase in
[Ca2+]i, is involved in the RhoA/ROK activation and sustained
contraction induced by K+. Ca2+ sensitization, myosin light chain
phosphatase, RhoA, Rho-associated kinase, tyrosine kinase
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Affiliation(s)
- Mitsuo Mita
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Hitoshi Tanaka
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Hayato Yanagihara
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Jun-ichi Nakagawa
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Shigeru Hishinuma
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
| | - Cindy Sutherland
- Smooth Muscle Research Group, Department of Biochemistry and
Molecular Biology, University of Calgary, Canada
| | - Michael P. Walsh
- Smooth Muscle Research Group, Department of Biochemistry and
Molecular Biology, University of Calgary, Canada
| | - Masaru Shoji
- Department of Pharmacodynamics, Meiji Pharmaceutical
University, Japan
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Ying Z, do Carmo JM, Xiang L, da Silva AA, Chen M, Ryan MJ, Ostrowski M, Rajagopalan S, Hall JE. Inhibitor κB kinase 2 is a myosin light chain kinase in vascular smooth muscle. Circ Res 2013; 113:562-70. [PMID: 23817200 DOI: 10.1161/circresaha.113.301510] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
RATIONALE Myosin light chain (MLC) phosphorylation determines vascular contractile status. In addition to the classic Ca²⁺-dependent MLC kinase (MLCK), another unidentified kinase(s) also contributes to MLC phosphorylation in living cells. Inhibitor κB kinase 2 (IKK2)-deficient mouse embryonic fibroblasts demonstrate abnormal morphology and migration, suggesting that IKK2 may be involved in MLC phosphorylation. OBJECTIVE Therefore, we tested whether IKK2 is an MLCK in living cells and the role of IKK2 in mediating vasoconstriction and blood pressure regulation. METHODS AND RESULTS In the present study, we showed that recombinant IKK2-phosphorylated MLC and intact myosin in vitro, and the kinetic parameters were comparable with those of the classic MLCK. Overexpression of IKK2 increased cellular MLC phosphorylation level, and pharmacological inhibition of IKK2 markedly decreased vascular smooth muscle cell MLC phosphorylation, suggesting that IKK2 is an MLCK in living cells. IKK2 inhibitors dose- and time-dependently attenuated vasoconstriction elicited by diverse agonists, suggesting the physiological importance of IKK2 as an MLCK. Vascular smooth muscle cell-specific IKK2-deficient mice had decreased aortic contractile responses, and reduced hypertensive responses to several vasoconstrictors, compared with wild-type mice, confirming the physiological importance of IKK2 as an MLCK. CONCLUSIONS Our data provide a novel mechanism whereby IKK2 regulates MLC phosphorylation as an MLCK and, thus, vascular function and blood pressure.
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Affiliation(s)
- Zhekang Ying
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA.
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Mitogen-activated protein kinases regulate vascular reactivity after hemorrhagic shock through myosin light chain phosphorylation pathway. J Trauma Acute Care Surg 2013; 74:1033-43. [PMID: 23511142 DOI: 10.1097/ta.0b013e31828586a2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Vascular hyporeactivity played an important role in many critical illness including shock or sepsis, but the mechanisms are incompletely understood. The objective of the present study was to investigate the roles of major mitogen-activated protein kinases (MAPKs extracellular signal-regulated kinase [ERK], p38 MAPK, and jun NH2-terminal kinase [JNK]) on vascular reactivity and the mechanisms. METHODS With superior mesenteric arteries from hemorrhagic shock rats, the role of p38 MAPK, ERK, and JNK in the regulation of vascular reactivity following shock and their relationship to myosin light chain (MLC20) phosphorylation-dependent pathway was observed. RESULTS ERK, p38 MAPK, and JNK activities in superior mesenteric arteries were increased at early shock and decreased at late shock. Stimulation of MAPKs with angiotensin II (AngII) increased the vascular reactivity, calcium sensitivity, and MLC20 phosphorylation. The increasing effect of AngII on vascular reactivity was antagonized by ERK, p38 MAPK, and JNK inhibitors, while the effect of AngII on calcium sensitivity was only blocked by ERK and p38 MAPK inhibitor, but not by JNK inhibitor. AngII increased the activity of protein kinase C-dependent phosphatase inhibitor of 17-kD (CPI17), integrin-linked kinase (ILK), and zipper-interacting protein kinase (ZIPK), The effect of AngII on CPI17 was blocked by ERK and p38 MAPK inhibitor, while the effect of AngII on ILK and ZIPK was only blocked by ERK inhibitor. CONCLUSION MAPKs participated in the regulation of vascular reactivity during shock. ERK and p38 MAPK is mainly through ILK, ZIPK, and CPI17-mediated MLC20 phosphorylation-dependent pathway, while JNK may be involved in the regulation of vascular reactivity by other mechanisms.
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The p90 ribosomal S6 kinase (RSK) is a mediator of smooth muscle contractility. PLoS One 2013; 8:e58703. [PMID: 23516539 PMCID: PMC3596281 DOI: 10.1371/journal.pone.0058703] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 02/05/2013] [Indexed: 11/19/2022] Open
Abstract
In the canonical model of smooth muscle (SM) contraction, the contractile force is generated by phosphorylation of the myosin regulatory light chain (RLC20) by the myosin light chain kinase (MLCK). Moreover, phosphorylation of the myosin targeting subunit (MYPT1) of the RLC20 phosphatase (MLCP) by the RhoA-dependent ROCK kinase, inhibits the phosphatase activity and consequently inhibits dephosphorylation of RLC20 with concomitant increase in contractile force, at constant intracellular [Ca2+]. This pathway is referred to as Ca2+-sensitization. There is, however, emerging evidence suggesting that additional Ser/Thr kinases may contribute to the regulatory pathways in SM. Here, we report data implicating the p90 ribosomal S6 kinase (RSK) in SM contractility. During both Ca2+- and agonist (U46619) induced SM contraction, RSK inhibition by the highly selective compound BI-D1870 (which has no effect on MLCK or ROCK) resulted in significant suppression of contractile force. Furthermore, phosphorylation levels of RLC20 and MYPT1 were both significantly decreased. Experiments involving the irreversible MLCP inhibitor microcystin-LR, in the absence of Ca2+, revealed that the decrease in phosphorylation levels of RLC20 upon RSK inhibition are not due solely to the increase in the phosphatase activity, but reflect direct or indirect phosphorylation of RLC20 by RSK. Finally, we show that agonist (U46619) stimulation of SM leads to activation of extracellular signal-regulated kinases ERK1/2 and PDK1, consistent with a canonical activation cascade for RSK. Thus, we demonstrate a novel and important physiological function of the p90 ribosomal S6 kinase, which to date has been typically associated with the regulation of gene expression.
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Derewenda U, Artamonov M, Szukalska G, Utepbergenov D, Olekhnovich N, Parikh HI, Kellogg GE, Somlyo AV, Derewenda ZS. Identification of quercitrin as an inhibitor of the p90 S6 ribosomal kinase (RSK): structure of its complex with the N-terminal domain of RSK2 at 1.8 Å resolution. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:266-75. [PMID: 23385462 PMCID: PMC3565440 DOI: 10.1107/s0907444912045520] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 11/03/2012] [Indexed: 02/07/2023]
Abstract
Members of the RSK family of kinases constitute attractive targets for drug design, but a lack of structural information regarding the mechanism of selective inhibitors impedes progress in this field. The crystal structure of the N-terminal kinase domain (residues 45-346) of mouse RSK2, or RSK2(NTKD), has recently been described in complex with one of only two known selective inhibitors, a rare naturally occurring flavonol glycoside, kaempferol 3-O-(3'',4''-di-O-acetyl-α-L-rhamnopyranoside), known as SL0101. Based on this structure, it was hypothesized that quercitrin (quercetin 3-O-α-L-rhamnopyranoside), a related but ubiquitous and inexpensive compound, might also act as an RSK inhibitor. Here, it is demonstrated that quercitrin binds to RSK2(NTKD) with a dissociation constant (K(d)) of 5.8 µM as determined by isothermal titration calorimetry, and a crystal structure of the binary complex at 1.8 Å resolution is reported. The crystal structure reveals a very similar mode of binding to that recently reported for SL0101. Closer inspection shows a number of small but significant differences that explain the slightly higher K(d) for quercitrin compared with SL0101. It is also shown that quercitrin can effectively substitute for SL0101 in a biological assay, in which it significantly suppresses the contractile force in rabbit pulmonary artery smooth muscle in response to Ca(2+).
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Affiliation(s)
- Urszula Derewenda
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
| | - Mykhaylo Artamonov
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
| | - Gabriela Szukalska
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
| | - Darkhan Utepbergenov
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
| | - Natalya Olekhnovich
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
| | - Hardik I. Parikh
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298-0540, USA
| | - Glen E. Kellogg
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298-0540, USA
| | - Avril V. Somlyo
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
| | - Zygmunt S. Derewenda
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736, USA
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Gao N, Huang J, He W, Zhu M, Kamm KE, Stull JT. Signaling through myosin light chain kinase in smooth muscles. J Biol Chem 2013; 288:7596-7605. [PMID: 23362260 DOI: 10.1074/jbc.m112.427112] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Ca(2+)/calmodulin-dependent myosin light chain kinase (MLCK) phosphorylates smooth muscle myosin regulatory light chain (RLC) to initiate contraction. We used a tamoxifen-activated, smooth muscle-specific inactivation of MLCK expression in adult mice to determine whether MLCK was differentially limiting in distinct smooth muscles. A 50% decrease in MLCK in urinary bladder smooth muscle had no effect on RLC phosphorylation or on contractile responses, whereas an 80% decrease resulted in only a 20% decrease in RLC phosphorylation and contractile responses to the muscarinic agonist carbachol. Phosphorylation of the myosin light chain phosphatase regulatory subunit MYPT1 at Thr-696 and Thr-853 and the inhibitor protein CPI-17 were also stimulated with carbachol. These results are consistent with the previous findings that activation of a small fraction of MLCK by limiting amounts of free Ca(2+)/calmodulin combined with myosin light chain phosphatase inhibition is sufficient for robust RLC phosphorylation and contractile responses in bladder smooth muscle. In contrast, a 50% decrease in MLCK in aortic smooth muscle resulted in 40% inhibition of RLC phosphorylation and aorta contractile responses, whereas a 90% decrease profoundly inhibited both responses. Thus, MLCK content is limiting for contraction in aortic smooth muscle. Phosphorylation of CPI-17 and MYPT1 at Thr-696 and Thr-853 were also stimulated with phenylephrine but significantly less than in bladder tissue. These results indicate differential contributions of MLCK to signaling. Limiting MLCK activity combined with modest Ca(2+) sensitization responses provide insights into how haploinsufficiency of MLCK may result in contractile dysfunction in vivo, leading to dissections of human thoracic aorta.
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Affiliation(s)
- Ning Gao
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Jian Huang
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Weiqi He
- Model Animal Research Center and Ministry of Education Key Laboratory of Model Animal for Disease Study, Nanjing University, 210061 Nanjing, China
| | - Minsheng Zhu
- Model Animal Research Center and Ministry of Education Key Laboratory of Model Animal for Disease Study, Nanjing University, 210061 Nanjing, China
| | - Kristine E Kamm
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - James T Stull
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390.
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Narang D, Kerr PM, Baserman J, Tam R, Yang W, Searle G, Manning-Fox JE, Paulsen IM, Kozuska JL, MacDonald PE, Light PE, Holt A, Plane F. Triton X-100 inhibits L-type voltage-operated calcium channels. Can J Physiol Pharmacol 2013; 91:316-24. [PMID: 23627843 DOI: 10.1139/cjpp-2012-0257] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Triton X-100 (TX-100) is a nonionic detergent frequently used at millimolar concentrations to disrupt cell membranes and solubilize proteins. At low micromolar concentrations, TX-100 has been reported to inhibit the function of potassium channels. Here, we have used electrophysiological and functional techniques to examine the effects of TX-100 on another class of ion channels, L-type voltage-operated calcium channels (VOCCs). TX-100 (30 nmol·L(-1) to 3 μmol·L(-1)) caused reversible concentration-dependent inhibition of recombinant L-type VOCC (CaV 1.2) currents and of native L-type VOCC currents recorded from rat vascular smooth muscle cells and cardiac myocytes, and murine and human pancreatic β-cells. In functional studies, TX-100 (165 nmol·L(-1) to 3.4 μmol·L(-1)) caused concentration-dependent relaxation of rat isolated mesenteric resistance arteries prestimulated with phenylephrine or KCl. This effect was independent of the endothelium. TX-100 (1.6 μmol·L(-1)) inhibited depolarization-induced exocytosis in both murine and human isolated pancreatic β-cells. These data indicate that at concentrations within the nanomolar to low micromolar range, TX-100 significantly inhibits L-type VOCC activity in a number of cell types, an effect paralleled by inhibition of cell functions dependent upon activation of these channels. This inhibition occurs at concentrations below those used to solubilize proteins and may compromise the use of solutions containing TX-100 in bioassays.
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Affiliation(s)
- Deepak Narang
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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MacDonald JA, Moffat LD, Al-Ghabkari A, Sutherland C, Walsh MP. Prostate-apoptosis response-4 phosphorylation in vascular smooth muscle. Arch Biochem Biophys 2012; 535:84-90. [PMID: 23219599 DOI: 10.1016/j.abb.2012.11.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 11/15/2012] [Accepted: 11/21/2012] [Indexed: 12/12/2022]
Abstract
The protein prostate-apoptosis response (Par)-4 has been implicated in the regulation of smooth muscle contraction, based largely on studies with the A7r5 cell line. A mechanism has been proposed whereby Par-4 binding to MYPT1 (the myosin-targeting subunit of myosin light chain phosphatase, MLCP) blocks access of zipper-interacting protein kinase (ZIPK) to Thr697 and Thr855 of MYPT1, whose phosphorylation is associated with MLCP inhibition. Phosphorylation of Par-4 at Thr155 disrupts its interaction with MYPT1, exposing the sites of phosphorylation in MYPT1 and leading to MLCP inhibition and contraction. We tested this "padlock" hypothesis in a well-characterized vascular smooth muscle system, the rat caudal artery. Par-4 was retained in Triton-skinned tissue, suggesting a tight association with the contractile machinery, and indeed Par-4 co-immunoprecipitated with MYPT1. Treatment of Triton-skinned tissue with the phosphatase inhibitor microcystin (MC) evoked phosphorylation of Par-4 at Thr155, but did not induce its dissociation from the contractile machinery. Furthermore, analysis of the time courses of MC-induced phosphorylation of MYPT1 and Par-4 revealed that MYPT1 phosphorylation at Thr697 or Thr855 preceded Par-4 phosphorylation. Par-4 phosphorylation was inhibited by the non-selective kinase inhibitor staurosporine, but not by inhibitors of ZIPK, Rho-associated kinase or protein kinase C. In addition, Par-4 phosphorylation did not occur upon addition of constitutively-active ZIPK to skinned tissue. We conclude that phosphorylation of Par-4 does not regulate contraction of this vascular smooth muscle tissue by inducing dissociation of Par-4 from MYPT1 to allow phosphorylation of MYPT1 and inhibition of MLCP.
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Affiliation(s)
- Justin A MacDonald
- Smooth Muscle Research Group and Department of Biochemistry & Molecular Biology, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, Canada T2N 4Z6.
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Grassie ME, Sutherland C, Ulke-Lemée A, Chappellaz M, Kiss E, Walsh MP, MacDonald JA. Cross-talk between Rho-associated kinase and cyclic nucleotide-dependent kinase signaling pathways in the regulation of smooth muscle myosin light chain phosphatase. J Biol Chem 2012; 287:36356-69. [PMID: 22948155 DOI: 10.1074/jbc.m112.398479] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ca(2+) sensitization of smooth muscle contraction depends upon the activities of protein kinases, including Rho-associated kinase, that phosphorylate the myosin phosphatase targeting subunit (MYPT1) at Thr(697) and/or Thr(855) (rat sequence numbering) to inhibit phosphatase activity and increase contractile force. Both Thr residues are preceded by the sequence RRS, and it has been suggested that phosphorylation at Ser(696) prevents phosphorylation at Thr(697). However, the effects of Ser(854) and dual Ser(696)-Thr(697) and Ser(854)-Thr(855) phosphorylations on myosin phosphatase activity and contraction are unknown. We characterized a suite of MYPT1 proteins and phosphospecific antibodies for specificity toward monophosphorylation events (Ser(696), Thr(697), Ser(854), and Thr(855)), Ser phosphorylation events (Ser(696)/Ser(854)) and dual Ser/Thr phosphorylation events (Ser(696)-Thr(697) and Ser(854)-Thr(855)). Dual phosphorylation at Ser(696)-Thr(697) and Ser(854)-Thr(855) by cyclic nucleotide-dependent protein kinases had no effect on myosin phosphatase activity, whereas phosphorylation at Thr(697) and Thr(855) by Rho-associated kinase inhibited phosphatase activity and prevented phosphorylation by cAMP-dependent protein kinase at the neighboring Ser residues. Forskolin induced phosphorylation at Ser(696), Thr(697), Ser(854), and Thr(855) in rat caudal artery, whereas U46619 induced Thr(697) and Thr(855) phosphorylation and prevented the Ser phosphorylation induced by forskolin. Furthermore, pretreatment with forskolin prevented U46619-induced Thr phosphorylations. We conclude that cross-talk between cyclic nucleotide and RhoA signaling pathways dictates the phosphorylation status of the Ser(696)-Thr(697) and Ser(854)-Thr(855) inhibitory regions of MYPT1 in situ, thereby regulating the activity of myosin phosphatase and contraction.
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Affiliation(s)
- Michael E Grassie
- Smooth Muscle Research Group and Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta T2N 4Z6, Canada
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New insights into myosin phosphorylation during cyclic nucleotide-mediated smooth muscle relaxation. J Muscle Res Cell Motil 2012; 33:471-83. [PMID: 22711245 PMCID: PMC3521644 DOI: 10.1007/s10974-012-9306-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 05/25/2012] [Indexed: 02/03/2023]
Abstract
Nitrovasodilators and agonists, via an increase in intracellular cyclic nucleotide levels, can induce smooth muscle relaxation without a concomitant decrease in phosphorylation of the regulatory light chains (RLC) of myosin. However, since cyclic nucleotide-induced relaxation is associated with a decrease in intracellular [Ca2+], and hence, a decreased activity of MLCK, we tested the hypothesis that the site responsible for the elevated RLC phosphorylation is not Ser19. Smooth muscle strips from gastric fundus were isometrically contracted with ET-1 which induced an increase in monophosphorylation from 9 ± 1 % under resting conditions (PSS) to 36 ± 1 % determined with 2D-PAGE. Electric field stimulation induced a rapid, largely NO-mediated relaxation with a half time of 8 s, which was associated with an initial decline in RLC phosphorylation to 18 % within 2 s and a rebound to 34 % after 30 s whereas relaxation was sustained. In contrast, phosphorylation of RLC at Ser19 probed with phosphospecific antibodies declined in parallel with force. LC/MS and western blot analysis with phosphospecific antibodies against monophosphorylated Thr18 indicate that Thr18 is significantly monophosphorylated during sustained relaxation. We therefore suggest that (i) monophosphorylation of Thr18 rather than Ser19 is responsible for the phosphorylation rebound during sustained EFS-induced relaxation of mouse gastric fundus, and (ii) that relaxation can be ascribed to dephosphorylation of Ser19, the site considered to be responsible for regulation of smooth muscle tone.
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Sutherland C, Walsh MP. Myosin regulatory light chain diphosphorylation slows relaxation of arterial smooth muscle. J Biol Chem 2012; 287:24064-76. [PMID: 22661704 DOI: 10.1074/jbc.m112.371609] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The principal signal to activate smooth muscle contraction is phosphorylation of the regulatory light chains of myosin (LC(20)) at Ser(19) by Ca(2+)/calmodulin-dependent myosin light chain kinase. Inhibition of myosin light chain phosphatase leads to Ca(2+)-independent phosphorylation at both Ser(19) and Thr(18) by integrin-linked kinase and/or zipper-interacting protein kinase. The functional effects of phosphorylation at Thr(18) on steady-state isometric force and relaxation rate were investigated in Triton-skinned rat caudal arterial smooth muscle strips. Sequential phosphorylation at Ser(19) and Thr(18) was achieved by treatment with adenosine 5'-O-(3-thiotriphosphate) in the presence of Ca(2+), which induced stoichiometric thiophosphorylation at Ser(19), followed by microcystin (phosphatase inhibitor) in the absence of Ca(2+), which induced phosphorylation at Thr(18). Phosphorylation at Thr(18) had no effect on steady-state force induced by Ser(19) thiophosphorylation. However, phosphorylation of Ser(19) or both Ser(19) and Thr(18) to comparable stoichiometries (0.5 mol of P(i)/mol of LC(20)) and similar levels of isometric force revealed differences in the rates of dephosphorylation and relaxation following removal of the stimulus: t(½) values for dephosphorylation were 83.3 and 560 s, and for relaxation were 560 and 1293 s, for monophosphorylated (Ser(19)) and diphosphorylated LC(20), respectively. We conclude that phosphorylation at Thr(18) decreases the rates of LC(20) dephosphorylation and smooth muscle relaxation compared with LC(20) phosphorylated exclusively at Ser(19). These effects of LC(20) diphosphorylation, combined with increased Ser(19) phosphorylation (Ca(2+)-independent), may underlie the hypercontractility that is observed in response to certain physiological contractile stimuli, and under pathological conditions such as cerebral and coronary arterial vasospasm, intimal hyperplasia, and hypertension.
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Affiliation(s)
- Cindy Sutherland
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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Hao YC, Yu LP, Li Q, Zhang XW, Zhao YP, He PY, Xu T, Wang XF. Effects of integrin-linked kinase on human corpus cavernosum smooth muscle cell cytoskeletal organisation. Andrologia 2012; 45:78-85. [PMID: 22616551 DOI: 10.1111/j.1439-0272.2012.01313.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2012] [Indexed: 11/26/2022] Open
Abstract
We investigated the effects of integrin-linked kinase (ILK) on the in vitro attachment, spreading, migration and microfilament dynamics of human corpus cavernosum smooth muscle cells. ILK small interfering RNA (siRNA) was used to transfect human corpus cavernosum smooth muscle cells; and cell attachment, spreading and migration were assessed. Additionally, microfilament dynamics were evaluated using Alexa Fluor 488 and phalloidin staining. We found that ILK gene knock-down significantly inhibited human corpus cavernosum smooth muscle cell attachment, spreading and migration. Moreover, blocking the expression of ILK disturbed actin cytoskeleton reorganisation and morphology in human corpus cavernosum smooth muscle cells. These results show that the targeting of ILK with siRNA significantly inhibited cell attachment, spreading, migration and microfilament dynamics in human corpus cavernosum smooth muscle cells. These findings indicate that ILK might be a potential therapeutic molecular target for the treatment of erectile dysfunction.
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Affiliation(s)
- Y-C Hao
- Urology Department, Peking University People's Hospital, Beijing, China
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Walsh MP. Vascular smooth muscle myosin light chain diphosphorylation: mechanism, function, and pathological implications. IUBMB Life 2011; 63:987-1000. [PMID: 21990256 DOI: 10.1002/iub.527] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 05/21/2011] [Accepted: 05/31/2011] [Indexed: 12/17/2022]
Abstract
Smooth muscle contraction is activated primarily by phosphorylation at S19 of the 20-kDa regulatory light chain subunits of myosin II (LC(20) ) catalyzed by Ca(2+) /calmodulin-dependent myosin light chain kinase. Other kinases, for example, integrin-linked kinase (ILK), Rho-associated kinase (ROCK), and zipper-interacting protein kinase (ZIPK), can phosphorylate T18 in addition to S19, which increases the actin-activated myosin MgATPase activity at subsaturating actin concentrations ∼3-fold. These phosphorylatable residues and the amino acid sequence surrounding them are highly conserved throughout the animal kingdom; they are also found in an LC(20) homolog within the genome of Monosiga brevicollis, the closest living relative of metazoans. LC(20) diphosphorylation has been detected in mammalian vascular smooth muscle tissues in response to specific contractile stimuli and in pathophysiological situations associated with hypercontractility. LC(20) diphosphorylation has also been observed frequently in cultured cells where it activates force generation. Kinases such as ILK, ROCK, and ZIPK, therefore, are potential therapeutic targets in the treatment of, for example, cerebral vasospasm following subarachnoid hemorrhage and atherosclerosis.
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Affiliation(s)
- Michael P Walsh
- Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada.
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Nepiyushchikh ZV, Chakraborty S, Wang W, Davis MJ, Zawieja DC, Muthuchamy M. Differential effects of myosin light chain kinase inhibition on contractility, force development and myosin light chain 20 phosphorylation of rat cervical and thoracic duct lymphatics. J Physiol 2011; 589:5415-29. [PMID: 21930597 DOI: 10.1113/jphysiol.2011.218446] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The intrinsic contractile activity of lymphatics varies in different regions of the body. We have previously shown that cervical lymphatics possess an inherently higher frequency but lower tone at a given pressure when compared to thoracic duct lymphatics. However, the molecular mechanisms modulating the contractile characteristics of these lymphatics are not well understood. Since myosin light chain 20 (MLC(20)) phosphorylation appears to underlie the tonic component of lymphatic contraction, we hypothesized that the thoracic duct would be more sensitive to the modulation of MLC(20) phosphorylation when compared to cervical lymphatics. To test our hypothesis, the contractile activities and MLC(20) phosphorylation of thoracic duct and cervical lymphatics were determined in the absence or presence of the specific myosin light chain kinase (MLCK) inhibitor ML-7 under both isobaric and isometric conditions. Addition of ML-7 at each concentration tested led to a decrease in tone in both vessel types. While ML-7 (10(-6) m) significantly reduced the phasic contraction frequency of cervical lymphatics, it completely stopped phasic contractions of thoracic duct at that concentration. Under isometric conditions the active peak and plateau components of tension were both significantly higher in thoracic duct compared to cervical lymphatics. ML-7 (10(-5) m) significantly decreased both the active peak and plateau tensions of thoracic duct, whereas only the active peak tension of cervical lymphatics was decreased. In thoracic duct MLC(20) di-phosphorylation, but not mono-phosphorylation, was significantly decreased with increasing transmural pressure, whereas in cervical vessels only at the higher pressures tested did MLC(20) di-phosphorylation decrease. ML-7 treatment of the thoracic duct caused a significant decrease in both the mono- and di-phosphorylated forms of MLC(20). However, in cervical vessels ML-7 treatment produced an increase in the mono-phosphorylated MLC(20) form while di-phosphorylated MLC(20) was significantly decreased. These data indicate that thoracic duct has an enhanced sensitivity to MLCK inhibition when compared to cervical lymphatics and while the status of the mono- and di-phosphorylation forms of MLC(20) affects both tonic and phasic components of lymphatic contractions, the pressure-dependent changes in tonic contractions are modulated by the status of the di-phosphorylation of MLC(20) in the lymphatics.
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Affiliation(s)
- Zhanna V Nepiyushchikh
- Department of Systems Biology and Translational Medicine, Cardiovascular Research Institute, Division of Lymphatic Biology, Texas A&M Health Science Center College of Medicine, 336 Reynolds Medical Building, College Station, TX 77843, USA
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Moffat LD, Brown SBA, Grassie ME, Ulke-Lemée A, Williamson LM, Walsh MP, MacDonald JA. Chemical genetics of zipper-interacting protein kinase reveal myosin light chain as a bona fide substrate in permeabilized arterial smooth muscle. J Biol Chem 2011; 286:36978-91. [PMID: 21880706 DOI: 10.1074/jbc.m111.257949] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Zipper-interacting protein kinase (ZIPK) has been implicated in Ca(2+)-independent smooth muscle contraction, although its specific role is unknown. The addition of ZIPK to demembranated rat caudal arterial strips induced an increase in force, which correlated with increases in LC(20) and MYPT1 phosphorylation. However, because of the number of kinases capable of phosphorylating LC(20) and MYPT1, it has proven difficult to identify the mechanism underlying ZIPK action. Therefore, we set out to identify bona fide ZIPK substrates using a chemical genetics method that takes advantage of ATP analogs with bulky substituents at the N(6) position and an engineered ZIPK capable of utilizing such substrates. (32)P-Labeled 6-phenyl-ATP and ZIPK-L93G mutant protein were added to permeabilized rat caudal arterial strips, and substrate proteins were detected by autoradiography following SDS-PAGE. Mass spectrometry identified LC(20) as a direct target of ZIPK in situ for the first time. Tissues were also exposed to 6-phenyl-ATP and ZIPK-L93G in the absence of endogenous ATP, and putative ZIPK substrates were identified by Western blotting. LC(20) was thereby confirmed as a direct target of ZIPK; however, no phosphorylation of MYPT1 was detected. We conclude that ZIPK is involved in the regulation of smooth muscle contraction through direct phosphorylation of LC(20).
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Affiliation(s)
- Lori D Moffat
- Smooth Muscle Research Group and the Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4Z6, Canada
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Shen D, Li J, Lepore JJ, Anderson TJT, Sinha S, Lin AY, Cheng L, Cohen ED, Roberts JD, Dedhar S, Parmacek MS, Gerszten RE. Aortic aneurysm generation in mice with targeted deletion of integrin-linked kinase in vascular smooth muscle cells. Circ Res 2011; 109:616-28. [PMID: 21778429 DOI: 10.1161/circresaha.110.239343] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
RATIONALE Integrin-linked kinase (ILK) is located at focal adhesions and links the extracellular matrix (ECM) to the actin cytoskeleton via β1- and β3-integrins. ILK plays a role in the activation of kinases including protein kinase B/Akt and glycogen synthase kinase 3β and regulates cell proliferation, motility, and survival. OBJECTIVE To determine the function of ILK in vascular smooth muscle cells (SMCs) in vivo. METHODS AND RESULTS SM22Cre(+)Ilk(Fl/Fl) conditional mutant mice were generated in which the Ilk gene was selectively ablated in SMCs. SM22Cre(+)Ilk(Fl/Fl) conditional mutant mice survive to birth but die in the perinatal period exhibiting multiple vascular pathologies including aneurysmal dilatation of the aorta and patent ductus arteriosus (PDA). Defects in morphogenetic development of the aorta were observed as early as E12.5 in SM22Cre(+)Ilk(Fl/Fl) mutant embryos. By late gestation (E16.5 to 18.5), striking expansion of the thoracic aorta was observed in ILK mutant embryos. Histological analyses revealed that the structural organization of the arterial tunica media is severely disrupted with profound derangements in SMC morphology, cell-cell, and cell-matrix relationships, including disruption of the elastic lamellae. ILK deletion in primary aortic SMCs results in alterations of RhoA/cytoskeletal signaling transduced through aberrant localization of myocardin-related transcription factor (MRTF)-A repressing the transcription and expression of SMC genes, which are required for the maintenance of the contractile SMC phenotype. CONCLUSIONS These data identify a molecular pathway linking ILK signaling to the contractile SMC gene program. Activation of this pathway is required for morphogenetic development of the aorta and ductus arteriosus during embryonic and postnatal survival.
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Affiliation(s)
- Dongxiao Shen
- Cardiovascular Research Center, Massachusetts General Hospital East-8307, Charlestown, MA 02129, USA
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Rho-kinase inhibition attenuates calcium-induced contraction in β-escin but not Triton X-100 permeabilized rabbit femoral artery. J Muscle Res Cell Motil 2011; 32:77-88. [PMID: 21706258 DOI: 10.1007/s10974-011-9253-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 05/31/2011] [Indexed: 01/09/2023]
Abstract
K+-depolarization (KCl) of smooth muscle has long been known to cause Ca2+-dependent contraction, but only recently has this G protein-coupled receptor (GPCR)-independent stimulus been associated with rhoA kinase (ROCK)-dependent myosin light chain (MLC) phosphatase inhibition and Ca2+ sensitization. This study examined effects of ROCK inhibition on the concentration-response curves (CRCs) generated in femoral artery by incrementally adding increasing concentrations of KCl to intact tissues, and Ca2+ to tissues permeabilized with Triton X-100, β-escin and α-toxin. For a comparison, tissue responses were assessed also in the presence of protein kinase C (PKC) and MLC kinase inhibition. The ROCK inhibitor H-1152 induced a strong concentration-dependent inhibition of a KCl CRC. A relatively low GF-109203X concentration (1 μM) sufficient to inhibit conventional PKC isotypes also inhibited the KCl CRC but did not affect the maximum tension. ROCK inhibitors had no effect on the Ca2+ CRC induced in Triton X-100 or α-toxin permeabilized tissues, but depressed the maximum contraction induced in β-escin permeabilized tissue. GF-109203X at 1 μM depressed the maximum Ca2+-dependent contraction induced in α-toxin permeabilized tissue and had no effect on the Ca2+ CRC induced in Triton X-100 permeabilized tissue. The MLC kinase inhibitor wortmannin (1 μM) strongly depression the Ca2+ CRCs in tissues permeabilized with Triton X-100, α-toxin and β-escin. H-1152 inhibited contractions induced by a single exposure to a submaximum [Ca2+] (pCa 6) in both rabbit and mouse femoral arteries. These data indicate that β-escin permeabilized muscle preserves GPCR-independent, Ca2+- and ROCK-dependent, Ca2+ sensitization.
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Aguilar HN, Tracey CN, Tsang SCF, McGinnis JM, Mitchell BF. Phos-tag-based analysis of myosin regulatory light chain phosphorylation in human uterine myocytes. PLoS One 2011; 6:e20903. [PMID: 21695279 PMCID: PMC3111472 DOI: 10.1371/journal.pone.0020903] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 05/12/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The 'phosphate-binding tag' (phos-tag) reagent enables separation of phospho-proteins during SDS-PAGE by impeding migration proportional to their phosphorylation stoichiometry. Western blotting can then be used to detect and quantify the bands corresponding to the phospho-states of a target protein. We present a method for quantification of data regarding phospho-states derived from phos-tag SDS-PAGE. The method incorporates corrections for lane-to-lane loading variability and for the effects of drug vehicles thus enabling the comparison of multiple treatments by using the untreated cellular set-point as a reference. This method is exemplified by quantifying the phosphorylation of myosin regulatory light chain (RLC) in cultured human uterine myocytes. METHODOLOGY/PRINCIPAL FINDINGS We have evaluated and validated the concept that, when using an antibody (Ab) against the total-protein, the sum of all phosphorylation states in a single lane represents a 'closed system' since all possible phospho-states and phosphoisotypes are detected. Using this approach, we demonstrate that oxytocin (OT) and calpeptin (Calp) induce RLC kinase (MLCK)- and rho-kinase (ROK)-dependent enhancements in phosphorylation of RLC at T18 and S19. Treatment of myocytes with a phorbol ester (PMA) induced phosphorylation of S1-RLC, which caused a mobility shift in the phos-tag matrices distinct from phosphorylation at S19. CONCLUSION/SIGNIFICANCE We have presented a method for analysis of phospho-state data that facilitates quantitative comparison to a reference control without the use of a traditional 'loading' or 'reference' standard. This analysis is useful for assessing effects of putative agonists and antagonists where all phospho-states are represented in control and experimental samples. We also demonstrated that phosphorylation of RLC at S1 is inducible in intact uterine myocytes, though the signal in the resting samples was not sufficiently abundant to allow quantification by the approach used here.
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Affiliation(s)
- Hector N. Aguilar
- Department of Physiology Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Curtis N. Tracey
- Department of Physiology Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Siu Cheung F. Tsang
- Department of Physiology Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Justin M. McGinnis
- Department of Physiology Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Bryan F. Mitchell
- Department of Physiology Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Department of Obstetrics and Gynecology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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Role of myosin light chain kinase and myosin light chain phosphatase in the resistance arterial myogenic response to intravascular pressure. Arch Biochem Biophys 2011; 510:160-73. [DOI: 10.1016/j.abb.2011.02.024] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/24/2011] [Accepted: 02/28/2011] [Indexed: 12/19/2022]
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Abstract
Integrin-linked kinase (ILK) is a highly evolutionarily conserved intracellular protein that was originally identified as an integrin-interacting protein, and extensive genetic and biochemical studies have shown that ILK expression is vital during both embryonic development and tissue homeostasis. At the cellular and tissue levels, ILK regulates signaling pathways for cell adhesion-mediated cell survival (anoikis), apoptosis, proliferation and mitosis, migration, invasion, and vascularization and tumor angiogenesis. ILK also has central roles in cardiac and smooth-muscle contractility, and ILK dysregulation causes cardiomyopathies in humans. ILK protein levels are increased in several human cancers and often the expression level predicts poor patient outcome. Abundant evidence has accumulated suggesting that, of the diverse functions of ILK, some may require kinase activity whereas others depend on protein-protein interactions and are, therefore, independent of kinase activity. However, the past several years have seen an ongoing debate about whether ILK indeed functions as a protein serine/threonine kinase. This debate centers on the atypical protein kinase domain of ILK, which lacks some amino-acid residues thought to be essential for phosphotransferase activity. However, similar deficiencies are present in the catalytic domains of other kinases now known to possess protein kinase activity. Numerous studies have shown that ILK phosphorylates peptide substrates in vitro, corresponding to ILK-mediated phosphorylations in intact cells, and a recent report characterizing in vitro phosphotransferase activity of highly purified, full-length ILK, accompanied by detailed enzyme kinetic analyses, shows that, at least in vitro, ILK is a bona fide protein kinase. However, several genetic studies suggest that, not all biological functions of ILK require kinase activity, and that it can function as an adaptor/scaffold protein. Here, we review evidence for and against ILK being an active kinase, and provide a framework for strategies to further analyze the kinase and adaptor functions of ILK in different cellular contexts.
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Ihara E, Akiho H, Nakamura K, Turner SR, MacDonald JA. MAPKs represent novel therapeutic targets for gastrointestinal motility disorders. World J Gastrointest Pathophysiol 2011; 2:19-25. [PMID: 21607162 PMCID: PMC3097965 DOI: 10.4291/wjgp.v2.i2.19] [Citation(s) in RCA: 5] [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: 09/17/2010] [Revised: 01/28/2011] [Accepted: 02/04/2011] [Indexed: 02/06/2023] Open
Abstract
The number of patients suffering from symptoms associated with gastrointestinal (GI) motility disorders is on the rise. GI motility disorders are accompanied by alteration of gastrointestinal smooth muscle functions. Currently available drugs, which can directly affect gastrointestinal smooth muscle and restore altered smooth muscle contractility to normal, are not satisfactory for treating patients with GI motility disorders. We have recently shown that ERK1/2 and p38MAPK signaling pathways play an important role in the contractile response not only of normal intestinal smooth muscle but also of inflamed intestinal smooth muscle. Here we discuss the possibility that ERK1/2 and p38MAPK signaling pathways represent ideal targets for generation of novel therapeutics for patients with GI motility disorders.
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