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Ran Q, Li A, Tan Y, Zhang Y, Zhang Y, Chen H. Action and therapeutic targets of myosin light chain kinase, an important cardiovascular signaling mechanism. Pharmacol Res 2024; 206:107276. [PMID: 38944220 DOI: 10.1016/j.phrs.2024.107276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Accepted: 06/19/2024] [Indexed: 07/01/2024]
Abstract
The global incidence of cardiac diseases is increasing, imposing a substantial socioeconomic burden on healthcare systems. The pathogenesis of cardiovascular disease is complex and not fully understood, and the physiological function of the heart is inextricably linked to well-regulated cardiac muscle movement. Myosin light chain kinase (MLCK) is essential for myocardial contraction and diastole, cardiac electrophysiological homeostasis, vasoconstriction of vascular nerves and blood pressure regulation. In this sense, MLCK appears to be an attractive therapeutic target for cardiac diseases. MLCK participates in myocardial cell movement and migration through diverse pathways, including regulation of calcium homeostasis, activation of myosin light chain phosphorylation, and stimulation of vascular smooth muscle cell contraction or relaxation. Recently, phosphorylation of myosin light chains has been shown to be closely associated with the activation of myocardial exercise signaling, and MLCK mediates systolic and diastolic functions of the heart through the interaction of myosin thick filaments and actin thin filaments. It works by upholding the integrity of the cytoskeleton, modifying the conformation of the myosin head, and modulating innervation. MLCK governs vasoconstriction and diastolic function and is associated with the activation of adrenergic and sympathetic nervous systems, extracellular transport, endothelial permeability, and the regulation of nitric oxide and angiotensin II. Additionally, MLCK plays a crucial role in the process of cardiac aging. Multiple natural products/phytochemicals and chemical compounds, such as quercetin, cyclosporin, and ML-7 hydrochloride, have been shown to regulate cardiomyocyte MLCK. The MLCK-modifying capacity of these compounds should be considered in designing novel therapeutic agents. This review summarizes the mechanism of action of MLCK in the cardiovascular system and the therapeutic potential of reported chemical compounds in cardiac diseases by modifying MLCK processes.
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Affiliation(s)
- Qingzhi Ran
- Guang'anmen Hospital, China Academy of Traditional Chinese Medicine, Beijing 100070, China
| | - Aoshuang Li
- Dongzhimen Hospital, Beijing University of Traditional Chinese Medicine, Beijing 100053, China
| | - Yuqing Tan
- Guang'anmen Hospital, China Academy of Traditional Chinese Medicine, Beijing 100070, China
| | - Yue Zhang
- Guang'anmen Hospital, China Academy of Traditional Chinese Medicine, Beijing 100070, China.
| | - Yongkang Zhang
- Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200082, China.
| | - Hengwen Chen
- Guang'anmen Hospital, China Academy of Traditional Chinese Medicine, Beijing 100070, China.
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Duan Y, Deng Y, Tang F, Li J. Lifibrate attenuates blood-brain barrier damage following ischemic stroke via the MLCK/p-MLC/ZO-1 axis. Aging (Albany NY) 2024; 16:6135-6146. [PMID: 38546384 PMCID: PMC11042934 DOI: 10.18632/aging.205692] [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: 10/16/2023] [Accepted: 01/23/2024] [Indexed: 04/23/2024]
Abstract
Dysfunction of tight junction proteins-associated damage to the blood-brain barrier (BBB) plays an important role in the pathogenesis of ischemic stroke. Lifibrate, an inhibitor of cholinephosphotransferase (CPT), has been used as an agent for serum lipid lowering. However, the protective effects of Lifibrate in ischemic stroke and the underlying mechanism have not been clearly elucidated. Here, we employed an in vivo mice model of MCAO and an OGD/R model in vitro. In the mice models, neurological deficit scores and infarct volume were assessed. Evans Blue solution was used to detect the BBB permeability. The TEER was examined to determine brain endothelial monolayer permeability. Here, we found that Lifibrate improved neurological dysfunction in stroke. Additionally, increased BBB permeability during stroke was significantly ameliorated by Lifibrate. Correspondingly, the reduced expression of the tight junction protein ZO-1 was restored by Lifibrate at both the mRNA and protein levels. Using an in vitro model, we found that Lifibrate ameliorated OGD/R-induced injury in human bEnd.3 brain microvascular endothelial cells by increasing cell viability but reducing the release of LDH. Importantly, Lifibrate suppressed the increase in endothelial monolayer permeability and the reduction in TEER induced by OGD/R via the rescue of ZO-1 expression. Mechanistically, Lifibrate blocked activation of the MLCK/ p-MLC signaling pathway in OGD/R-stimulated bEnd.3 cells. In contrast, overexpression of MLCK abolished the protective effects of Lifibrate in endothelial monolayer permeability, TEER, as well as the expression of ZO-1. Our results provide a basis for further investigation into the neuroprotective mechanism of Lifibrate during stroke.
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Affiliation(s)
- Yu Duan
- Department of Neurosurgery, Huadong Hospital Affiliated to Fudan University, Jing’an, Shanghai 200040, China
| | - Yao Deng
- Department of Neurosurgery, Huadong Hospital Affiliated to Fudan University, Jing’an, Shanghai 200040, China
| | - Feng Tang
- Department of Neurosurgery, Huadong Hospital Affiliated to Fudan University, Jing’an, Shanghai 200040, China
| | - Jian Li
- Department of Neurosurgery, Huadong Hospital Affiliated to Fudan University, Jing’an, Shanghai 200040, China
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Sorensen DW, Injeti ER, Mejia-Aguilar L, Williams JM, Pearce WJ. Postnatal development alters functional compartmentalization of myosin light chain kinase in ovine carotid arteries. Am J Physiol Regul Integr Comp Physiol 2021; 321:R441-R453. [PMID: 34318702 PMCID: PMC8530762 DOI: 10.1152/ajpregu.00293.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The rate-limiting enzyme for vascular contraction, myosin light chain kinase (MLCK), phosphorylates regulatory myosin light chain (MLC20) at rates that appear faster despite lower MLCK abundance in fetal compared with adult arteries. This study explores the hypothesis that greater apparent tissue activity of MLCK in fetal arteries is due to age-dependent differences in intracellular distribution of MLCK in relation to MLC20. Under optimal conditions, common carotid artery homogenates from nonpregnant adult female sheep and near-term fetuses exhibited similar values of Vmax and Km for MLCK. A custom-designed, computer-controlled apparatus enabled electrical stimulation and high-speed freezing of arterial segments at exactly 0, 1, 2, and 3 s, calculation of in situ rates of MLC20 phosphorylation, and measurement of time-dependent colocalization between MLCK and MLC20. The in situ rate of MLC20 phosphorylation divided by total MLCK abundance averaged to values 147% greater in fetal (1.06 ± 0.28) than adult (0.43 ± 0.08) arteries, which corresponded, respectively, to 43 ± 10% and 31 ± 3% of the Vmax values measured in homogenates. Confocal colocalization analysis revealed in fetal and adult arteries that 33 ± 6% and 20 ± 5% of total MLCK colocalized with pMLC20, and that MLCK activation was greater in periluminal than periadventitial regions over the time course of electrical stimulation in both age groups. Together, these results demonstrate that the catalytic activity of MLCK is similar in fetal and adult arteries, but that the fraction of total MLCK in the functional compartment involved in contraction is significantly greater in fetal than adult arteries.
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Affiliation(s)
- Dane W Sorensen
- Division of Physiology, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California
| | - Elisha R Injeti
- Department of Pharmaceutical Sciences, Cedarville University School of Pharmacy, Cedarville, Ohio
| | - Luisa Mejia-Aguilar
- Division of Physiology, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California
| | - James M Williams
- Division of Physiology, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California
| | - William J Pearce
- Division of Physiology, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California
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Tanaka H, Ishimaru S, Nagatsuka Y, Ohashi K. Smooth muscle-like Ca 2+-regulation of actin-myosin interaction in adult jellyfish striated muscle. Sci Rep 2018; 8:7776. [PMID: 29773804 PMCID: PMC5958069 DOI: 10.1038/s41598-018-24817-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 04/10/2018] [Indexed: 12/21/2022] Open
Abstract
Cnidaria is an animal phylum, whose members probably have the most ancestral musculature. We prepared and characterized, for the first time to our knowledge, native actomyosin from the striated myoepithelium of the adult moon jelly Aurelia sp. The actomyosin contained myosin, paramyosin-like protein, Ser/Thr-kinase, actin, and two isoforms of tropomyosin, but not troponin, which is known to activate contraction dependent on intracellular Ca2+ signaling in almost all striated muscles of bilaterians. Notably, the myosin comprised striated muscle-type heavy chain and smooth muscle-type regulatory light chains. In the presence of Ca2+, the Mg-ATPase activity of actomyosin was stimulated and Ser21 of the regulatory light chain was concomitantly phosphorylated by the addition of calmodulin and myosin light chain kinase prepared from chicken smooth muscle. Collectively, these results suggest that, similar to smooth muscle, the contraction of jellyfish striated muscle is regulated by Ca2+-dependent phosphorylation of the myosin light chain.
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Affiliation(s)
- Hiroyuki Tanaka
- Laboratory of Marine Biotechnology and Microbiology, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Japan.
| | - Shiori Ishimaru
- Laboratory of Marine Biotechnology and Microbiology, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Japan
| | - Yasuhiro Nagatsuka
- Laboratory of Marine Biotechnology and Microbiology, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Japan
| | - Keisuke Ohashi
- Laboratory of Marine Biotechnology and Microbiology, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Japan
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Xin X, Liu X, Li X, Ding X, Yang S, Jin C, Li G, Guo H. Comparative muscle proteomics/phosphoproteomics analysis provides new insight for the biosafety evaluation of fat-1 transgenic cattle. Transgenic Res 2017; 26:625-638. [DOI: 10.1007/s11248-017-0032-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 07/04/2017] [Indexed: 02/03/2023]
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Sundararajan V, Gengenbacher N, Stemmler MP, Kleemann JA, Brabletz T, Brabletz S. The ZEB1/miR-200c feedback loop regulates invasion via actin interacting proteins MYLK and TKS5. Oncotarget 2016; 6:27083-96. [PMID: 26334100 PMCID: PMC4694975 DOI: 10.18632/oncotarget.4807] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/07/2015] [Indexed: 02/06/2023] Open
Abstract
Epithelial to mesenchymal transition (EMT) is a developmental process which is aberrantly activated during cancer invasion and metastasis. Elevated expression of EMT-inducers like ZEB1 enables tumor cells to detach from the primary tumor and invade into the surrounding tissue. The main antagonist of ZEB1 in controlling EMT is the microRNA-200 family that is reciprocally linked to ZEB1 in a double negative feedback loop. Here, we further elucidate how the ZEB1/miR-200 feedback loop controls invasion of tumor cells. The process of EMT is attended by major changes in the actin cytoskeleton. Via in silico screening of genes encoding for actin interacting proteins, we identified two novel targets of miR-200c - TKS5 and MYLK (MLCK). Co-expression of both genes with ZEB1 was observed in several cancer cell lines as well as in breast cancer patients and correlated with low miR-200c levels. Depletion of TKS5 or MYLK in breast cancer cells reduced their invasive potential and their ability to form invadopodia. Whereas TKS5 is known to be a major component, we could identify MYLK as a novel player in invadopodia formation. In summary, TKS5 and MYLK represent two mediators of invasive behavior of cancer cells that are regulated by the ZEB1/miR-200 feedback loop.
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Affiliation(s)
- Vignesh Sundararajan
- Department of Visceral Surgery, University Medical Center Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Nicolas Gengenbacher
- Division of Vascular Oncology and Metastasis, German Cancer Research Center (DKFZ-ZMBH Alliance), Heidelberg, Germany
| | - Marc P Stemmler
- Department of Experimental Medicine I, Nikolaus-Fiebiger-Center for Molecular Medicine, University Erlangen-Nürnberg, Erlangen, Germany
| | - Julia A Kleemann
- Department of Experimental Medicine I, Nikolaus-Fiebiger-Center for Molecular Medicine, University Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas Brabletz
- Department of Experimental Medicine I, Nikolaus-Fiebiger-Center for Molecular Medicine, University Erlangen-Nürnberg, Erlangen, Germany
| | - Simone Brabletz
- Department of Experimental Medicine I, Nikolaus-Fiebiger-Center for Molecular Medicine, University Erlangen-Nürnberg, Erlangen, Germany
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Tanaka H, Wang HH, Thatcher SE, Hagiwara H, Takano-Ohmuro H, Kohama K. Electron microscopic examination of podosomes induced by phorbol 12, 13 dibutyrate on the surface of A7r5 cells. J Pharmacol Sci 2015; 128:78-82. [PMID: 25986486 DOI: 10.1016/j.jphs.2015.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 11/17/2022] Open
Abstract
The role of myosin light chain kinase (MLCK) in inducing podosomes was examined by confocal and electron microscopy. Removal of myosin from the actin core of podosomes using blebbistatin, a myosin inhibitor, resulted in the formation of smaller podosomes. Downregulation of MLCK by the transfection of MLCK small interfering RNA (siRNA) led to the failure of podosome formation. However, ML-7, an inhibitor of the kinase activity of MLCK, failed to inhibit podosome formation. Based on our previous report (Thatcher et al. J.Pharm.Sci. 116 116-127, 2011), we outlined the important role of the actin-binding activity of MLCK in producing smaller podosomes.
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Affiliation(s)
- Hideyuki Tanaka
- Department of Anatomy, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Hong-Hui Wang
- Department of Cellular and Molecular Medicine, University of California San Diego, 9500 Gillman Drive 0651, La Jolla, CA 92093-0651, USA; College of Biology, Hunan University, No.1 Denggao Road, Yuelushan, Changsha, Hunan 410082, PR China
| | - Sean E Thatcher
- Department of Nutritional Sciences, University of Kentucky, Charles T.Wethington Bldg, 900 South Limestone, Lexington, KY 40536-0200, USA
| | - Haruo Hagiwara
- Department of Anatomy, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Hiromi Takano-Ohmuro
- Research Institute of Pharmaceutical Sciences, Musashino University, Nishitokyo, Tokyo 202-8585, Japan
| | - Kazuhiro Kohama
- Research Institute of Pharmaceutical Sciences, Musashino University, Nishitokyo, Tokyo 202-8585, Japan.
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Abstract
AIM: To investigate the expression of myosin light chain kinase (MLCK) in pancreatic tissue of severe acute pancreatitis (SAP) rats.
METHODS: Fifty-six male SD rats were randomly and equally assigned into a normal control group (C) and a SAP group (S). SAP was reproduced in rats of group S by retrograde injection of 4% sodium taurocholate into the biliopancreatic duct, while group C underwent a sham operation. The rats were killed at 6, 12, 24 and 48 h after SAP induction. Serum amylase (AMY) was measured dynamically. The gross and pathological changes in the pancreas were observed under a light microscope. The ultrastructure and tight junction (TJ) changes in the pancreas were observed with an electron microscope. The localization and expression of MLCK in pancreatic tissue were investigated by immunohistochemical method. The concentration of serum tumor necrosis factor α (TNF-α) was determined by ELISA.
RESULTS: Compared to group C, the AMY concentration and pancreatic pathology score were significantly higher (P < 0.05); pancreatic ultrastructure damage was more obvious and TJ widened significantly; MLCK was positively expressed in the cytoplasm of cells in the pancreas, and the mean density was elevated more significantly (P < 0.05); and serum TNF-α concentration significantly increased in group S (P < 0.05). The mean density of MLCK in the pancreas was positively correlated with pathological score and serum TNF-α concentration (r = 0.804, 0.796, P < 0.05 for both).
CONCLUSION: Up-regulated expression of MLCK protein in the pancreas and elevated serum TNF-α concentration may regulate the integrity of intercellular tight junctions, which may be associated with the severity of SAP and play a role in the pathogenesis of acute pancreatitis.
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Adeoye OO, Bouthors V, Hubbell MC, Williams JM, Pearce WJ. VEGF receptors mediate hypoxic remodeling of adult ovine carotid arteries. J Appl Physiol (1985) 2014; 117:777-87. [PMID: 25038104 DOI: 10.1152/japplphysiol.00012.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent studies suggest that VEGF contributes to hypoxic remodeling of arterial smooth muscle, although hypoxia produces only transient increases in VEGF that return to normoxic levels despite sustained changes in arterial structure and function. To explore how VEGF might contribute to long-term hypoxic vascular remodeling, this study explores the hypothesis that chronic hypoxia produces sustained increases in smooth muscle VEGF receptor density that mediate long-term vascular effects of hypoxia. Carotid arteries from adult sheep maintained at sea level or altitude (3,820 m) for 110 days were harvested and denuded of endothelium. VEGF levels were similar in chronically hypoxic and normoxic arteries, as determined by immunoblotting. In contrast, VEGF receptor levels were significantly increased by 107% (VEGF-R1) and 156% (VEGF-R2) in hypoxic compared with normoxic arteries. In arteries that were organ cultured 24 h with 3 nM VEGF, VEGF replicated effects of hypoxia on abundances of smooth muscle α actin (SMαA), myosin light chain kinase (MLCK), and MLC20 and the effects of hypoxia on colocalization of MLC20 with SMαA, as measured via confocal microscopy. VEGF did not replicate the effects of chronic hypoxia on colocalization of MLCK with SMαA or MLCK with MLC20, suggesting that VEGF's role in hypoxic remodeling is highly protein specific, particularly for contractile protein organization. VEGF effects in organ culture were inhibited by VEGF receptor blockers vatalinib (240 nM) and dasatinib (6.3 nM). These findings support the hypothesis that long-term upregulation of VEGF receptors help mediate sustained effects of hypoxia on the abundance and colocalization of contractile proteins in arterial smooth muscle.
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Affiliation(s)
- Olayemi O Adeoye
- Divisions of Physiology, Pharmacology, and Biochemistry, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California
| | - Vincent Bouthors
- Divisions of Physiology, Pharmacology, and Biochemistry, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California
| | - Margaret C Hubbell
- Divisions of Physiology, Pharmacology, and Biochemistry, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California
| | - James M Williams
- Divisions of Physiology, Pharmacology, and Biochemistry, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California
| | - William J Pearce
- Divisions of Physiology, Pharmacology, and Biochemistry, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, California
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Guo WL, Zhang Q, Wang J, Jin MF. Higher expression of phosphorylated myosin regulatory light chain in the common bile duct in pancreaticobiliary maljunction accompanied by bile duct dilatation in children: a post-mortem observational study. Pediatr Surg Int 2013; 29:293-8. [PMID: 23224623 PMCID: PMC3575553 DOI: 10.1007/s00383-012-3225-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/19/2012] [Indexed: 02/07/2023]
Abstract
PURPOSE To examine the content of phosphorylated myosin regulatory light chain (P-MLC20) and myosin light-chain kinase (MLCK) in the common bile duct of pediatric patients with pancreaticobiliary maljunction (PBM) accompanied by bile duct dilatation (BDD), and investigate their potential role in PBM accompanied by BDD. METHODS Twenty-one specimens of the common bile duct from pediatric patients with PBM accompanied by BDD were collected. P-MLC20 was examined with immunohistochemistry. The expression of P-MLC20 and MLCK was also examined with Western blot. Twenty-one specimens of the common bile duct from pediatric patients without PBM and BDD were used as controls. RESULTS The mean optical density (MOD), mean labeling intensity (MLI) and minimum qualifying scores (MQS) of P-MLC20 were 115.6856 ± 58.1634, 21.7125 % ± 9.6555 and 21.3531 ± 6.5255, respectively. In the control group, MOD, MLI and MQS were 96.5581 ± 9.7859, 11.1813 % ± 3.6208 and 10.7819 ± 3.5323, respectively. There was no significant difference in MOD between the two groups (P > 0.05), whereas there was a significant difference in MLI and MQS between the two groups (P < 0.05). The expression of P-MLC20 and MLCK, as determined with Western blot, was also significantly higher in the PBM group than in the control group (P < 0.05). CONCLUSION P-MLC20 is associated with increased contractile force of the smooth muscle of the common bile duct in pediatric patients with PBM accompanied by BDD. The enhanced expression of P-MLC20 in the common bile duct probably contributes to increased bile duct pressure in PBM via the MLCK pathway.
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Affiliation(s)
- Wan-liang Guo
- Radiology Department, Children’s Hospital Affiliated to Soochow University, Suzhou, China
| | - Qi Zhang
- Pediatric General Surgery Department, Children’s Hospital Affiliated to Soochow University, 215003 Suzhou, China
| | - Jian Wang
- Pediatric General Surgery Department, Children’s Hospital Affiliated to Soochow University, 215003 Suzhou, China
| | - Mei-fang Jin
- Pediatric General Surgery Department, Children’s Hospital Affiliated to Soochow University, 215003 Suzhou, China
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Myosin light chain kinase is involved in the mechanism of gastrointestinal dysfunction in diabetic rats. Dig Dis Sci 2012; 57:1197-202. [PMID: 22302242 DOI: 10.1007/s10620-012-2041-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 01/04/2012] [Indexed: 12/09/2022]
Abstract
BACKGROUND It is well established that smooth muscle contractility is regulated by an elevation of cytosolic Ca(2+) via myosin light chain phosphorylation, which is activated by myosin light chain kinase (MLCK). Recently, MLCK has been demonstrated to play an important role in smooth muscle contraction and normal gastrointestinal motility. AIMS The aim of our study is to investigate whether MLCK is involved in the mechanism of gastrointestinal dysfunction and the ameliorating effects of insulin on gastrointestinal dysfunction in diabetic rats. METHODS A diabetic rat model was established by an intravenous injection with streptozotocin. Rats were randomized into three groups: control group, diabetic group, and insulin-treated group. The gastrointestinal functions were assessed in terms of gastric emptying and intestinal transit. The expression of MLCK in the pylorus and ileum of the three groups was determined by real-time polymerase chain reaction (PCR) and Western blot methods. RESULTS The diabetic group exhibited a significant delay in gastric emptying and intestinal transit than the control group. Insulin treatment significantly ameliorated the gastric emptying and intestinal transit in diabetic rats. The expression levels of MLCK in the pylorus and ileum of the diabetic group were both significantly decreased compared with the control group, and the changes of MLCK expression in these tissues of diabetic rats were partially reversed after treatment with insulin. CONCLUSIONS Decreased expression of MLCK in gastrointestinal tissues could be a possible cause for gastrointestinal dysfunction. Insulin may partly ameliorate gastrointestinal dysfunction by restoring the expression of MLCK.
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Wang HH, Nakamura A, Yoshiyama S, Ishikawa R, Cai N, Ye LH, Takano-Ohmuro H, Kohama K. Down-Regulation of Myosin Light Chain Kinase Expression in Vascular Smooth Muscle Cells Accelerates Cell Proliferation: Requirement of Its Actin-binding Domain for Reversion to Normal Rates. J Pharmacol Sci 2012; 119:91-6. [DOI: 10.1254/jphs.11213sc] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Hong F, Haldeman BD, Jackson D, Carter M, Baker JE, Cremo CR. Biochemistry of smooth muscle myosin light chain kinase. Arch Biochem Biophys 2011. [PMID: 21565153 DOI: 10.1016/j.abb.2011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The smooth muscle isoform of myosin light chain kinase (MLCK) is a Ca(2+)-calmodulin-activated kinase that is found in many tissues. It is particularly important for regulating smooth muscle contraction by phosphorylation of myosin. This review summarizes selected aspects of recent biochemical work on MLCK that pertains to its function in smooth muscle. In general, the focus of the review is on new findings, unresolved issues, and areas with the potential for high physiological significance that need further study. The review includes a concise summary of the structure, substrates, and enzyme activity, followed by a discussion of the factors that may limit the effective activity of MLCK in the muscle. The interactions of each of the many domains of MLCK with the proteins of the contractile apparatus, and the multi-domain interactions of MLCK that may control its behaviors in the cell are summarized. Finally, new in vitro approaches to studying the mechanism of phosphorylation of myosin are introduced.
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Affiliation(s)
- Feng Hong
- Department of Biochemistry and Molecular Biology, University of Nevada School of Medicine, Reno, 89557, USA
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14
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Biochemistry of smooth muscle myosin light chain kinase. Arch Biochem Biophys 2011; 510:135-46. [PMID: 21565153 DOI: 10.1016/j.abb.2011.04.018] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 04/22/2011] [Accepted: 04/25/2011] [Indexed: 11/23/2022]
Abstract
The smooth muscle isoform of myosin light chain kinase (MLCK) is a Ca(2+)-calmodulin-activated kinase that is found in many tissues. It is particularly important for regulating smooth muscle contraction by phosphorylation of myosin. This review summarizes selected aspects of recent biochemical work on MLCK that pertains to its function in smooth muscle. In general, the focus of the review is on new findings, unresolved issues, and areas with the potential for high physiological significance that need further study. The review includes a concise summary of the structure, substrates, and enzyme activity, followed by a discussion of the factors that may limit the effective activity of MLCK in the muscle. The interactions of each of the many domains of MLCK with the proteins of the contractile apparatus, and the multi-domain interactions of MLCK that may control its behaviors in the cell are summarized. Finally, new in vitro approaches to studying the mechanism of phosphorylation of myosin are introduced.
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Thatcher SE, Fultz ME, Tanaka H, Hagiwara H, Zhang HL, Zhang Y, Hayakawa K, Yoshiyama S, Nakamura A, Wang HH, Katayama T, Watanabe M, Lin Y, Wright GL, Kohama K. Myosin Light Chain Kinase / Actin Interaction in Phorbol Dibutyrate–Stimulated Smooth Muscle Cells. J Pharmacol Sci 2011; 116:116-27. [DOI: 10.1254/jphs.10296fp] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Abstract
Caffeine is the most widely consumed stimulating substance in the world. It is found in coffee, tea, soft drinks, chocolate, and many medications. Caffeine is a xanthine with various effects and mechanisms of action in vascular tissue. In endothelial cells, it increases intracellular calcium stimulating the production of nitric oxide through the expression of the endothelial nitric oxide synthase enzyme. Nitric oxide is diffused to the vascular smooth muscle cell to produce vasodilation. In vascular smooth muscle cells its effect is predominantly a competitive inhibition of phosphodiesterase, producing an accumulation of cAMP and vasodilation. In addition, it blocks the adenosine receptors present in the vascular tissue to produce vasoconstriction. In this paper the main mechanisms of action of caffeine on the vascular tissue are described, in which it is shown that caffeine has some cardiovascular properties and effects which could be considered beneficial.
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Deng M, Ding W, Min X, Xia Y. MLCK-independent phosphorylation of MLC20 and its regulation by MAP kinase pathway in human bladder smooth muscle cells. Cytoskeleton (Hoboken) 2010; 68:139-49. [PMID: 20722044 DOI: 10.1002/cm.20471] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 01/10/2011] [Accepted: 01/10/2011] [Indexed: 01/11/2023]
Abstract
Myosins are a superfamily of actin-based molecular motor proteins, which hydrolyze ATP and generate various forms of eukaryotic motility and muscle contraction. Myosin light chain 20 (MLC20) is small ring around the neck region of heavy chain of myosins. Phosphorylation of MLC20 is thought to play a key role in regulation of smooth muscle contraction. Calcium- and calmodulin-dependent myosin light chain kinase (MLCK) is considered the primary regulator of MLC20 phosphorylation. However, several observations in smooth muscle contraction cannot be explained by the mode of phosphorylation. By performing a series of experiments in vitro and in vivo, we report here MLCK-independent MLC20 phosphorylation. Gene expression study reveals that expression of MLCK in smooth muscles is inconsistent with MLC20 phosphorylation at Ser19. None of inactivating calmodulin/MLCK, depriving of calcium and silencing MLCK expression by siRNA blocks effectively the phosphorylation of MLC20 at Ser19. In addition, by overexpressing active human MAP (mitogen-activated protein)-ERK kinase kinase-1 (MEKK1) and blocking its downstream messengers, we have demonstrated a new regulatory system of MLC phosphorylation via MEKK1, which downregulates Ser19 phosphorylation of MLC20 through its downstream molecules, p38, JNK, and ERK in human bladder smooth muscle cells.
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Affiliation(s)
- Maoxian Deng
- Department of Animal Biology, School of Animal Husbandry and Veterinary Medicine, Jiangsu Polytechnic College of Agriculture and Forestry, Jurong, Jiangsu, China.
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Xie C, Zhang Y, Wang HH, Matsumoto A, Nakamura A, Ishikawa R, Yoshiyama S, Hayakawa K, Kohama K, Gao Y. Calcium regulation of non-kinase and kinase activities of recombinant myosin light-chain kinase and its mutants. IUBMB Life 2010; 61:1092-8. [PMID: 19859981 DOI: 10.1002/iub.266] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Myosin light-chain kinase (MLCK) comprised of N-terminal actin-binding domain, central catalytic domain, and C-terminal myosin-binding domain. It exerted not only kinase activity to phosphorylate 20 kDa regulatory light chain of smooth muscle but also exerted non-kinase activity on myosin motor and myosin ATPase activities (Nakamura et al., Biochem. Biophys. Res. Commun. 2008, 369, 135). The previous studies on the multiple MLCK functions were done using MLCK fragments. The present study reported the expression of whole MLCK molecules in Escherichia coli in a large amount. The construct in which the calmodulin (CaM) binding domain for regulating kinase activity was mutated lost the kinase activity. However, the mutant exerted non-kinase activity and inhibited both myosin motor and ATPase activities. The domain that regulated kinase activity was also shown to be involved in the Ca(2+) regulation of non-kinase activity. The deletion mutants of actin-binding domain which located at N-terminal 1-41 amino acids demonstrated that non-kinase activity was mediated through actin filaments.
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Affiliation(s)
- Ce Xie
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Maebashi, Japan
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19
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Katayama T, Watanabe M, Tanaka H, Hino M, Miyakawa T, Ohki T, Ye LH, Xie C, Yoshiyama S, Nakamura A, Ishikawa R, Tanokura M, Oiwa K, Kohama K. Stimulatory effects of arachidonic acid on myosin ATPase activity and contraction of smooth muscle via myosin motor domain. Am J Physiol Heart Circ Physiol 2010; 298:H505-14. [DOI: 10.1152/ajpheart.00577.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have been searching for a mechanism to induce smooth muscle contraction that is not associated with phosphorylation of the regulatory light chain (RLC) of smooth muscle myosin (Nakamura A, Xie C, Zhang Y, Gao Y, Wang HH, Ye LH, Kishi H, Okagaki T, Yoshiyama S, Hayakawa K, Ishikawa R, Kohama K. Biochem Biophys Res Commun 369: 135–143, 2008). In this article, we report that arachidonic acid (AA) stimulates ATPase activity of unphosphorylated smooth muscle myosin with maximal stimulation (Rmax) of 6.84 ± 0.51 relative to stimulation by the vehicle and with a half-maximal effective concentration (EC50) of 50.3 ± 4.2 μM. In the presence of actin, Rmax was 1.72 ± 0.08 and EC50 was 26.3 ± 2.3 μM. Our experiments with eicosanoids consisting of the AA cascade suggested that they neither stimulated nor inhibited the activity. Under conditions that did not allow RLC to be phosphorylated, AA stimulated contraction of smooth muscle tissue with an Rmax of 1.45 ± 0.07 and an EC50 of 27.0 ± 4.4 μM. In addition to the ATPase activities of the myosin, AA stimulated those of heavy meromyosin, subfragment 1 (S1), S1 from which the RLC was removed, and a recombinant heavy chain consisting of the myosin head. The stimulatory effects of AA on these preparations were about twofold. The site of AA action was indicated to be the step-releasing inorganic phosphate (Pi) from the reaction intermediate of the myosin-ADP-Pi complex. The enhancement of Pi release by AA was supported by computer simulation indicating that AA docked in the actin-binding cleft of the myosin motor domain. The stimulatory effect of AA was detectable with both unphosphorylated myosin and the myosin in which RLC was fully phosphorylated. The AA effect on both myosin forms was suggested to cause excess contraction such as vasospasm.
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Affiliation(s)
- Takeshi Katayama
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Gunma
| | | | - Hideyuki Tanaka
- Department of Research Science, Gunma University School of Health Sciences, Gunma
| | - Mizuki Hino
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Gunma
| | - Takuya Miyakawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo
| | - Takashi Ohki
- Department of Physics, School of Science and Engineering, Waseda University, Tokyo
| | - Li-Hong Ye
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Gunma
- Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin, China; and
| | - Ce Xie
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Gunma
| | - Shinji Yoshiyama
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Gunma
| | - Akio Nakamura
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Gunma
| | - Ryoki Ishikawa
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Gunma
| | - Masaru Tanokura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo
| | | | - Kazuhiro Kohama
- Department of Molecular and Cellular Pharmacology, Gunma University Graduate School of Medicine, Gunma
- Department of Biological Sciences, Marshall University, Huntington, West Virginia
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20
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Nakamura A. [The non-kinase activity of myosin light chain kinase in regulating smooth muscle contraction]. Nihon Yakurigaku Zasshi 2009; 133:144-148. [PMID: 19282617 DOI: 10.1254/fpj.133.144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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21
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Wang HH, Nakamura A, Matsumoto A, Yoshiyama S, Qin X, Ye LH, Xie C, Zhang Y, Gao Y, Ishikawa R, Kohama K. Nonkinase activity of MLCK in elongated filopodia formation and chemotaxis of vascular smooth muscle cells toward sphingosylphosphorylcholine. Am J Physiol Heart Circ Physiol 2009; 296:H1683-93. [PMID: 19234090 DOI: 10.1152/ajpheart.00965.2008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The actin-myosin interaction of vascular smooth muscle cells (VSMCs) is regulated by myosin light chain kinase (MLCK), which is a fusion protein of the central catalytic domain with the N-terminal actin-binding and C-terminal myosin-binding domains. In addition to the regulatory role of kinase activity mediated by the catalytic domain, nonkinase activity that derives from both terminals is able to exert a regulatory role as reviewed by Nakamura et al. (32). We previously showed that nonkinase activity mediated the filopodia upon the stimulation by sphingosylphosphorylcholine (SPC) (25). To explore the regulatory role of nonkinase activity in chemotaxis, we constructed VSMCs where the expression of MLCK was totally abolished by using a lentivirus-mediated RNAi system. We hypothesized that the MLCK-downregulated VSMCs were unable to form filopodia and to migrate upon SPC stimulation and confirmed the hypothesis. We further constructed a kinase-inactive mutant from bovine cDNA coding wild-type (WT) MLCK by mutating the ATP-binding sites located in the catalytic domain, followed by confirming the presence (absence) of the kinase activity of WT (kinase-inactive mutant). We transfected WT and the mutant into MLCK-downregulated VSMCs. We expected that the transfected VSMCs will recover the ability to induce filopodia and chemotaxis toward SPC and found both constructs rescued the ability. Because they share the actin- and myosin-binding domains, we concluded nonkinase activity plays a major role for SPC-induced migration.
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Affiliation(s)
- Hong Hui Wang
- Dept. of Molecular and Cellular Pharmacology, Faculty of Medicine, Gunma Univ. Graduate School of Medicine 3-39-22 Showa-Machi, Maebashi, Gunma 371-8511, Japan
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