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Rezaei M, Mehta JL, Zadeh GM, Khedri A, Rezaei HB. Myosin light chain phosphatase is a downstream target of Rho-kinase in endothelin-1-induced transactivation of the TGF-β receptor. Cell Biochem Biophys 2024; 82:1109-1120. [PMID: 38834831 DOI: 10.1007/s12013-024-01262-4] [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] [Accepted: 03/22/2024] [Indexed: 06/06/2024]
Abstract
BACKGROUND Rho-kinase (ROCK) regulates actomyosin contraction, coronary vasospasm, and cytoskeleton dynamics. ROCK and of NADPH oxidase (NOX) play an essential role in cardiovascular disease and proteoglycan synthesis, which promotes atherosclerosis by trapping low density lipoprotein. ROCK is activated by endothelin-1 (ET1) and transactivates the transforming growth factor beta receptor (TGFβR1), intensifying Smad signaling and proteoglycan production. This study aimed to identify the role of myosin light chain phosphatase (MLCP) as a downstream target of ROCK in TβR1 transactivation. METHODS Vascular smooth muscle cells were treated with ET1 and inhibitors of ROCK and MLCP were added. The phosphorylation levels of Smad2C, myosin light chain (MLC), and MLCP were monitored by western blot, and the mRNA expression of chondroitin 4-O-sulfotransferase 1 (C4ST1) was assessed by quantitative real-time PCR. RESULTS We examined ROCK's role in ET1-induced TGFβR1 activation. ROCK phosphorylated MLCP at the MYPT1 T853 residue, blocked by the ROCK inhibitor Y27632. ROCK also increased MLC phosphorylation and actomyosin contraction in response to ET1, enhanced by the phosphatase inhibitor Calyculin A. Calyculin A also increased C4ST1 expression, GAG-chain synthesizing enzymes. CONCLUSIONS This work suggests that ROCK is involved in ET1-mediated TβR1 activation through increased MLCP phosphorylation, which leads to Smad2C phosphorylation and stimulates C4ST1 expression.
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Affiliation(s)
- Maryam Rezaei
- Hyperlipidemia Research Center, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Jawahar Lal Mehta
- Division of Cardiology, Central Arkansas Veterans Healthcare System and the University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Ghorban Mohammad Zadeh
- Hyperlipidemia Research Center, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Azam Khedri
- Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Hossein Babaahmadi Rezaei
- Hyperlipidemia Research Center, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
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2
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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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3
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Larson KF, Malik A, Brozovich FV. Aging and Heart Failure with Preserved Ejection Fraction. Compr Physiol 2022; 12:3813-3822. [PMID: 35950652 DOI: 10.1002/cphy.c210035] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Heart failure is a clinical syndrome characterized by the inability of the cardiovascular system to provide adequate cardiac output at normal filling pressures. This results in a clinical syndrome characterized by dyspnea, edema, and decreased exertional tolerance. Heart failure with preserved ejection fraction (HFpEF) is an increasingly common disease, and the incidence of HFpEF increases with age. There are a variety of factors which contribute to the development of HFpEF, including the presence of hypertension, diabetes, obesity, and other pro-inflammatory states. These comorbid conditions result in changes at the biochemical and cell signaling level which ultimately lead to a disease with a great deal of phenotypic heterogeneity. In general, the physiologic dysfunction of HFpEF is characterized by vascular stiffness, increased cardiac filling pressures, pulmonary hypertension, and impaired volume management. The normal and abnormal processes associated with aging serve as an accelerant in this process, resulting in the hypothesis that HFpEF represents a form of presbycardia. In this article, we aim to review the processes importance of aging in the development of HFpEF by examining the disease and its causes from the biochemical to physiologic level. © 2022 American Physiological Society. Compr Physiol 12: 1-10, 2022.
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Affiliation(s)
- Kathryn F Larson
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Awais Malik
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Frank V Brozovich
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Physiology, Mayo Clinic, Rochester, Minnesota, USA
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4
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Schwaerzer GK, Casteel DE, Cividini F, Kalyanaraman H, Zhuang S, Gu Y, Peterson KL, Dillmann W, Boss GR, Pilz RB, Pilz RB. Constitutive protein kinase G activation exacerbates stress-induced cardiomyopathy. Br J Pharmacol 2022; 179:2413-2429. [PMID: 34000062 PMCID: PMC9926932 DOI: 10.1111/bph.15530] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Heart failure is associated with high morbidity and mortality, and new therapeutic targets are needed. Preclinical data suggest that pharmacological activation of protein kinase G (PKG) can reduce maladaptive ventricular remodelling and cardiac dysfunction in the stressed heart. However, clinical trial results have been mixed and the effects of long-term PKG activation in the heart are unknown. EXPERIMENTAL APPROACH We characterized the cardiac phenotype of mice carrying a heterozygous knock-in mutation of PKG1 (Prkg1R177Q/+ ), which causes constitutive, cGMP-independent activation of the kinase. We examined isolated cardiac myocytes and intact mice, the latter after stress induced by surgical transaortic constriction or angiotensin II (Ang II) infusion. KEY RESULTS Cardiac myocytes from Prkg1R177Q/+ mice showed altered phosphorylation of sarcomeric proteins and reduced contractility in response to electrical stimulation, compared to cells from wild type mice. Under basal conditions, young PKG1R177Q/+ mice exhibited no obvious cardiac abnormalities, but aging animals developed mild increases in cardiac fibrosis. In response to angiotensin II infusion or fixed pressure overload induced by transaortic constriction, young PKGR177Q/+ mice exhibited excessive hypertrophic remodelling with increased fibrosis and myocyte apoptosis, leading to increased left ventricular dilation and dysfunction compared to wild type litter mates. CONCLUSION AND IMPLICATIONS Long-term PKG1 activation in mice may be harmful to the heart, especially in the presence of pressure overload and neurohumoral stress. LINKED ARTICLES This article is part of a themed issue on cGMP Signalling in Cell Growth and Survival. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.11/issuetoc.
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Affiliation(s)
- Gerburg K. Schwaerzer
- Department of Medicine, University of California San Diego, La Jolla, California 92093,These three authors contributed equally to the work
| | - Darren E. Casteel
- Department of Medicine, University of California San Diego, La Jolla, California 92093,These three authors contributed equally to the work
| | - Federico Cividini
- Department of Medicine, University of California San Diego, La Jolla, California 92093,These three authors contributed equally to the work
| | - Hema Kalyanaraman
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Shunhui Zhuang
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Yusu Gu
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Kirk L. Peterson
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Wolfgang Dillmann
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Gerry R. Boss
- Department of Medicine, University of California San Diego, La Jolla, California 92093
| | - Renate B. Pilz
- Department of Medicine, University of California San Diego, La Jolla, California 92093,Correspondence should be addressed to R.B.P. ()
| | - Renate B Pilz
- Department of Medicine, University of California San Diego, La Jolla, California, 92093, USA
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5
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Oslin K, Reho JJ, Lu Y, Khanal S, Kenchegowda D, Prior SJ, Fisher SA. Tissue-specific expression of myosin phosphatase subunits and isoforms in smooth muscle of mice and humans. Am J Physiol Regul Integr Comp Physiol 2022; 322:R281-R291. [PMID: 35107022 PMCID: PMC8917933 DOI: 10.1152/ajpregu.00196.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 01/24/2022] [Accepted: 01/24/2022] [Indexed: 11/22/2022]
Abstract
Alternative splicing of exon24 (E24) of myosin phosphatase targeting subunit 1 (Mypt1) by setting sensitivity to nitric oxide (NO)/cGMP-mediated relaxation is a key determinant of smooth muscle function. Here we defined expression of myosin phosphatase (MP) subunits and isoforms by creation of new genetic mouse models, assay of human and mouse tissues, and query of public databases. A Mypt1-LacZ reporter mouse revealed that Mypt1 transcription is turned on early in development during smooth muscle differentiation. Mypt1 is not as tightly restricted in its expression as smooth muscle myosin heavy chain (Myh11) and its E6 splice variant. Mypt1 is enriched in mature smooth versus nonmuscle cells. The E24 splice variant and leucine zipper minus protein isoform that it encodes is enriched in phasic versus tonic smooth muscle. In the vascular system, E24 splicing increases as vessel size decreases. In the gastrointestinal system, E24 splicing is most predominant in smooth muscle of the small intestine. Tissue-specific expression of MP subunits and Mypt1 E24 splicing is conserved in humans, whereas a splice variant of the inhibitory subunit (CPI-17) is unique to humans. A Mypt1 E24 mini-gene splicing reporter mouse generated to define patterns of E24 splicing in smooth muscle cells (SMCs) dispersed throughout the organ systems was unsuccessful. In summary, expression of Mypt1 and splicing of E24 is part of the program of smooth muscle differentiation, is further enhanced in phasic smooth muscle, and is conserved in humans. Its low-level expression in nonmuscle cells may confound its measurement in tissue samples.
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Affiliation(s)
- Kimberly Oslin
- University of Maryland-Baltimore Scholars Program, Baltimore, Maryland
| | - John J Reho
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Yuan Lu
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Sunita Khanal
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Doreswamy Kenchegowda
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Steven J Prior
- Baltimore Veterans Affairs Medical Center, Baltimore, Maryland
- Department of Kinesiology, University of Maryland School of Public Health, College Park, Maryland
- Baltimore Veterans Affairs Geriatric Research Education and Clinical Center, and Research and Development Service, Baltimore, Maryland
| | - Steven A Fisher
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
- Baltimore Veterans Affairs Medical Center, Baltimore, Maryland
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6
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Lubomirov LT, Jänsch MH, Papadopoulos S, Schroeter MM, Metzler D, Bust M, Hescheler J, Grisk O, Ritter O, Pfitzer G. Senescent murine femoral arteries undergo vascular remodelling associated with accelerated stress-induced contractility and reactivity to nitric oxide. Basic Clin Pharmacol Toxicol 2021; 130:70-83. [PMID: 34665520 DOI: 10.1111/bcpt.13675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Indexed: 12/17/2022]
Abstract
This work explored the mechanism of augmented stress-induced vascular reactivity of senescent murine femoral arteries (FAs). Mechanical and pharmacological reactivity of young (12-25 weeks, y-FA) and senescent (>104 weeks, s-FAs) femoral arteries was measured by wire myography. Expression and protein phosphorylation of selected regulatory proteins were studied by western blotting. Expression ratio of the Exon24 in/out splice isoforms of the regulatory subunit of myosin phosphatase, MYPT1 (MYPT1-Exon24 in/out), was determined by polymerase chain reaction (PCR). While the resting length-tension relationship showed no alteration, the stretch-induced-tone increased to 8.3 ± 0.9 mN in s-FA versus only 4.6 ± 0.3 mN in y-FAs. Under basal conditions, phosphorylation of the regulatory light chain of myosin at S19 was 19.2 ± 5.8% in y-FA versus 49.2 ± 12.6% in s-FA. Inhibition of endogenous NO release raised tone additionally to 10.4 ± 1.2 mN in s-FA, whereas this treatment had a negligible effect in y-FAs (4.8 ± 0.3 mN). In s-FAs, reactivity to NO donor was augmented (pD2 = -4.5 ± 0.3 in y-FA vs. -5.2 ± 0.1 in senescent). Accordingly, in s-FAs, MYPT1-Exon24-out-mRNA, which is responsible for expression of the more sensitive to protein-kinase G, leucine-zipper-positive MYPT1 isoform, was increased. The present work provides evidence that senescent murine s-FA undergoes vascular remodelling associated with increases in stretch-activated contractility and sensitivity to NO/cGMP/PKG system.
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Affiliation(s)
- Lubomir T Lubomirov
- Institute of Physiology, Brandenburg Medical School Theodor Fontane, Neuruppin, Germany.,Institute of Vegetative Physiology, Center of Physiology, University of Cologne, Cologne, Germany.,Research Cluster, Molecular Mechanisms of Cardiovascular Diseases, Brandenburg Medical School Theodor Fontane, Neuruppin, Germany
| | - Monique Heidrun Jänsch
- Research Cluster, Molecular Mechanisms of Cardiovascular Diseases, Brandenburg Medical School Theodor Fontane, Neuruppin, Germany.,Department of Cardiology, Nephrology and Pneumology, Brandenburg Medical School, University Hospital Brandenburg, Brandenburg an der Havel, Germany
| | - Symeon Papadopoulos
- Institute of Neurophysiology, Center of Physiology, University of Cologne, Cologne, Germany
| | - Mechthild M Schroeter
- Institute of Vegetative Physiology, Center of Physiology, University of Cologne, Cologne, Germany
| | - Doris Metzler
- Institute of Vegetative Physiology, Center of Physiology, University of Cologne, Cologne, Germany
| | - Maria Bust
- Institute of Vegetative Physiology, Center of Physiology, University of Cologne, Cologne, Germany
| | - Jürgen Hescheler
- Institute of Neurophysiology, Center of Physiology, University of Cologne, Cologne, Germany
| | - Olaf Grisk
- Institute of Physiology, Brandenburg Medical School Theodor Fontane, Neuruppin, Germany.,Research Cluster, Molecular Mechanisms of Cardiovascular Diseases, Brandenburg Medical School Theodor Fontane, Neuruppin, Germany
| | - Oliver Ritter
- Research Cluster, Molecular Mechanisms of Cardiovascular Diseases, Brandenburg Medical School Theodor Fontane, Neuruppin, Germany.,Department of Cardiology, Nephrology and Pneumology, Brandenburg Medical School, University Hospital Brandenburg, Brandenburg an der Havel, Germany
| | - Gabriele Pfitzer
- Institute of Vegetative Physiology, Center of Physiology, University of Cologne, Cologne, Germany
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7
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Cui Y, Yang L, Liu X, Che C, Cheng J, Li P, Wen J, Yang Y. The decrease of MYPT1 is critical for impairment of NO-mediated vosodilation in mesenteric artery of the older spontaneously hypertensive rats. J Gerontol A Biol Sci Med Sci 2021; 77:424-432. [PMID: 34614147 DOI: 10.1093/gerona/glab290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 11/13/2022] Open
Abstract
Nitric oxide (NO) mediated vasodilatation is a fundamental response of vasculature, however, the regulation of NO signaling pathway on resistance vessels in the elderly hypertension is still unclear. The 16-weeks-spontaneously hypertensive rats (SHR), the 18-months-SHR (OldSHR), and the age matched Wistar-Kyoto rats were used to study the changes of mesenteric resistance artery dilatation caused by sodium nitroprusside (SNP). After pre-vasoconstriction by Norepinephrine (NE), the response of endothelium-denuded mesenteric artery ring to SNP was observed, and the changes in vascular response after pharmacological interventions of key nodes in the NO/sGC/cGMP/PKG1α signaling pathway were observed as well. RNA sequencing and functional enrichment analyses were used to provide information for conducting validation experiments. Vasodilation of NO in OldSHR was decreased, which significantly correlated with the reduction of PKG-mediated effect. Functional enrichment analysis of RNA sequencing showed that genes encoding important proteins such as sGC and MYPT1 (protein phosphatase 1 regulatory subunit 12A) were downregulated in OldSHR. Molecular biology validation results showed that mRNA expression of both α and β subunits of sGC were reduced, while mRNA and protein expression of PKG1α were reduced in OldSHR. More importantly, the expression of MYPT1 and p S668-MYPT1 was significantly reduced in OldSHR, even under the treatment of SNP. The experiment also revealed an enhanced cAMP system in vasodilatory in hypertension, while this function completely lost in the elderly hypertension. Therefore, a NO-mediated decrease in vascular smooth muscle relaxation was found in the elderly hypertension. The dysfunction in cGMP-PKG signaling, in particular, the decreased p S668-MYPT1 was mechanistically involved.
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Affiliation(s)
- Yiqin Cui
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University
| | - Liju Yang
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University.,Department of Cardiology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
| | - Xiaoqin Liu
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University
| | - Chang Che
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University
| | - Jun Cheng
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University
| | - Pengyu Li
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University
| | - Jing Wen
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University
| | - Yan Yang
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Lab of Sichuan Province, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease, Institute of Cardiovascular Research, Southwest Medical University.,Department of Cardiology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, China
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8
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Lyle MA, Alabdaljabar MS, Han YS, Brozovich FV. The vasculature in HFpEF vs HFrEF: differences in contractile protein expression produce distinct phenotypes. Heliyon 2020; 6:e03129. [PMID: 31909283 PMCID: PMC6940630 DOI: 10.1016/j.heliyon.2019.e03129] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 11/21/2019] [Accepted: 12/23/2019] [Indexed: 12/14/2022] Open
Abstract
Both heart failure with reduced (HFrEF) and preserved (HFpEF) ejection fraction are associated with abnormalities of the vasculature, including a resting vasoconstriction and a decrease in sensitivity to nitric oxide (NO) mediated vasodilation. Vascular tone is controlled by the expression and activation of both smooth muscle (SM) and nonmuscle (NM) myosin, and NO mediated vasodilation is regulated by the expression of the leucine zipper positive (LZ+) isoform of the myosin targeting subunit (MYPT1) of myosin light chain phosphatase (MLCP). This study was designed to determine the expression of these contractile proteins in humans with HFrEF and HFpEF vs normal controls. We isolated tertiary mesenteric vessels from remnant biospecimens of patients undergoing partial or total colectomy at Mayo Clinic Rochester from August 2017 to December 2018, and examined the expression of MYPT1 and the LZ + MYPT1 isoform with immunoblots, while 2D SDS-PAGE was used to resolve the phosphorylated and nonphosphorylated regulatory light chains of NM and SM myosin. Our data show that NM myosin expression, as a percentage of total myosin, was 12 ± 3% (controls, n = 6), 7 ± 5% (HFpEF, n = 4) and 37 ± 18% (HFrEF, n = 5, p < 0.05). Total MYPT1 expression was significantly reduced (p < 0.05) in both HFpEF (70 ± 11%) and HFrEF (48 ± 6%); and in HFrEF, LZ + MYPT1 was also depressed (62 ± 19%, <0.05). These results demonstrate that HFrEF and HFpEF are distinct vascular entities, and the changes in protein expression contribute to the vascular abnormalities associated with these diseases. Further in HFpEF, the decrease in MYPT1 would explain why pharmacologic therapies that are designed to activate the NO/cGMP/PKG signaling pathway do not produce a clinical benefit.
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Affiliation(s)
- Melissa A. Lyle
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, 55905, USA
| | | | - Young Soo Han
- Department of Physiology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Frank V. Brozovich
- Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, 55905, USA
- Department of Physiology, Mayo Clinic, Rochester, MN, 55905, USA
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9
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MLCK and ROCK mutualism in endothelial barrier dysfunction. Biochimie 2020; 168:83-91. [DOI: 10.1016/j.biochi.2019.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 10/22/2019] [Indexed: 01/15/2023]
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10
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Lubomirov LT, Gagov H, Schroeter MM, Wiesner RJ, Franko A. Augmented contractility of murine femoral arteries in a streptozotocin diabetes model is related to increased phosphorylation of MYPT1. Physiol Rep 2019; 7:e13975. [PMID: 30740930 PMCID: PMC6369311 DOI: 10.14814/phy2.13975] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 12/19/2022] Open
Abstract
Diabetes mellitus (DM) is a metabolic disorder with high prevalence, and a major risk factor for macro- and microvascular abnormalities. This study was undertaken to explore the mechanisms of hypercontractility of murine femoral arteries (FA) obtained from mice with streptozotocin (STZ)-induced diabetes and its relation to the phosphorylation profile of the myosin phosphatase target subunit 1, MYPT1. The immunoreactivity of MYPT1 toward phospho-MYPT1-T696, MYPT1-T853, or MYPT1-S695, used as a read out for MYPT1 phosphorylation, has been studied by Western Blotting. Contractile activity of FA from control and STZ mice has been studied by wire myography. At basal conditions (no treatment), the immunoreactivity of MYPT1-T696/T853 was ~2-fold higher in the STZ arteries compared with controls. No changes in MYPT1-T696/853 phosphorylation were observed after stimulation with the Thromboxan-A2 analog, U46619. Neither basal nor U46619-stimulated phosphorylation of MYPT1 at S695 was affected by STZ treatment. Mechanical distensibility and basal tone of FA obtained from STZ animals were similar to controls. Maximal force after treatment of FA with the contractile agonists phenylephrine (10 μmol/L) or U46619 (1 μmol/L) was augmented in the arteries of STZ mice by ~2- and ~1.5-fold, respectively. In summary, our study suggests that development of a hypercontractile phenotype in murine FA in STZ diabetes is at least partially related to an increase in phosphorylation of MLCP at MYPT1-T696/853. Interestingly, the phosphorylation at S695 site was not altered in STZ-induced diabetes, supporting the view that S695 may serve as a sensor for mechanical activity which is not directly involved in tone regulation.
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Affiliation(s)
| | - Hristo Gagov
- Faculty of BiologySofia University St. Kliment OhridskiSofiaBulgaria
| | | | - Rudolf J. Wiesner
- Institute of Vegetative PhysiologyUniversity of CologneKölnGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)KölnGermany
| | - Andras Franko
- Institute of Vegetative PhysiologyUniversity of CologneKölnGermany
- German Center for Diabetes Research (DZD e.V.)NeuherbergGermany
- Division of EndocrinologyDepartment of Internal Medicine IVDiabetology, Angiology, Nephrology and Clinical ChemistryUniversity of TübingenTübingenGermany
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11
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LaFlamme A, Young KE, Lang I, Weiser DC. Alternative splicing of (ppp1r12a/mypt1) in zebrafish produces a novel myosin phosphatase targeting subunit. Gene 2018; 675:15-26. [PMID: 29960069 PMCID: PMC6123272 DOI: 10.1016/j.gene.2018.06.092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 06/07/2018] [Accepted: 06/26/2018] [Indexed: 01/04/2023]
Abstract
Myosin phosphatase is an evolutionarily conserved regulator of actomyosin contractility, comprised of a regulatory subunit (Mypt1), and a catalytic subunit (PP1). Zebrafish has become an ideal model organism for the study of the genetic and cell physiological role of the myosin phosphatase in morphogenesis and embryonic development. We identified and characterized a novel splice variant of Mypt1 (ppp1r12a-tv202) from zebrafish, which is widely expressed during early embryonic development. Importantly, mutant alleles and antisense morpholinos that have been used to demonstrate the important role of Mypt1 in early development, not only disrupt the longer splice variants, but also tv202. The protein product of ppp1r12a-tv202 (Mypt1-202) contains the PP1-binding N-terminus, but lacks the regulatory C-terminus, which contains two highly conserved inhibitory phosphorylation sites. We observed that the protein product of tv202 assembled a constitutively active myosin phosphatase uninhibited by kinases such as Zipk. Thus, we propose that Mypt1-202 plays an important role in maintaining baseline Mlc2 dephosphorylation and actomyosin relaxation during early zebrafish development.
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Affiliation(s)
- Andrew LaFlamme
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Kyle E Young
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Irene Lang
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA
| | - Douglas C Weiser
- Department of Biological Sciences, University of the Pacific, Stockton, CA 95211, USA.
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12
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Sheehe JL, Bonev AD, Schmoker AM, Ballif BA, Nelson MT, Moon TM, Dostmann WR. Oxidation of cysteine 117 stimulates constitutive activation of the type Iα cGMP-dependent protein kinase. J Biol Chem 2018; 293:16791-16802. [PMID: 30206122 PMCID: PMC6204908 DOI: 10.1074/jbc.ra118.004363] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 09/04/2018] [Indexed: 12/22/2022] Open
Abstract
The type I cGMP-dependent protein kinase (PKG I) is an essential regulator of vascular tone. It has been demonstrated that the type Iα isoform can be constitutively activated by oxidizing conditions. However, the amino acid residues implicated in this phenomenon are not fully elucidated. To investigate the molecular basis for this mechanism, we studied the effects of oxidation using recombinant WT, truncated, and mutant constructs of PKG I. Using an in vitro assay, we observed that oxidation with hydrogen peroxide (H2O2) resulted in constitutive, cGMP-independent activation of PKG Iα. PKG Iα C42S and a truncation construct that does not contain Cys-42 (Δ53) were both constitutively activated by H2O2 In contrast, oxidation of PKG Iα C117S maintained its cGMP-dependent activation characteristics, although oxidized PKG Iα C195S did not. To corroborate these results, we also tested the effects of our constructs on the PKG Iα-specific substrate, the large conductance potassium channel (KCa 1.1). Application of WT PKG Iα activated by either cGMP or H2O2 increased the open probabilities of the channel. Neither cGMP nor H2O2 activation of PKG Iα C42S significantly increased channel open probabilities. Moreover, cGMP-stimulated PKG Iα C117S increased KCa 1.1 activity, but this effect was not observed under oxidizing conditions. Finally, we observed that PKG Iα C42S caused channel flickers, indicating dramatically altered KCa 1.1 channel characteristics compared with channels exposed to WT PKG Iα. Cumulatively, these results indicate that constitutive activation of PKG Iα proceeds through oxidation of Cys-117 and further suggest that the formation of a sulfur acid is necessary for this phenotype.
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Affiliation(s)
- Jessica L Sheehe
- From the Department of Pharmacology, Larner College of Medicine, and
| | - Adrian D Bonev
- From the Department of Pharmacology, Larner College of Medicine, and
| | - Anna M Schmoker
- the Department of Biology, University of Vermont, Burlington, Vermont 05405 and
| | - Bryan A Ballif
- the Department of Biology, University of Vermont, Burlington, Vermont 05405 and
| | - Mark T Nelson
- From the Department of Pharmacology, Larner College of Medicine, and
| | - Thomas M Moon
- the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
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13
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Lyle MA, Brozovich FV. HFpEF, a Disease of the Vasculature: A Closer Look at the Other Half. Mayo Clin Proc 2018; 93:1305-1314. [PMID: 30064827 DOI: 10.1016/j.mayocp.2018.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 04/12/2018] [Accepted: 05/04/2018] [Indexed: 12/31/2022]
Abstract
Patients with heart failure are commonly divided into those with reduced ejection fraction (EF<40%) and those with preserved ejection fraction (HFpEF; EF>50%). For heart failure with reduced EF, a number of therapies have been found to improve patient morbidity and mortality, and treatment is guideline based. However for patients with HFpEF, no treatment has been found to have clinical benefit. To objectively assess treatments for HFpEF, a comprehensive PubMed literature search was performed using the terms HFpEF, heart failure, smooth muscle, myosin, myosin phosphatase, and PKG (up to December 31, 2017), with an unbiased focus on pathophysiology, cell signaling, and therapy. This review provides evidence that could explain the lack of clinical benefit in treating patients with HFpEF with sildenafil and long-acting nitrates. Furthermore, the review highlights the vascular abnormalities present in patients with HFpEF, and these abnormalities of the vasculature could potentially contribute to the pathophysiology of HFpEF. Thus, focusing on HFpEF as a vascular disease could result in the development of novel and effective treatment paradigms.
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Affiliation(s)
- Melissa A Lyle
- Department of Cadiovascular Diseases, Mayo Clinic College of Medicine and Science, Rochester, MN
| | - Frank V Brozovich
- Department of Cadiovascular Diseases, Mayo Clinic College of Medicine and Science, Rochester, MN.
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14
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Lubomirov LT, Papadopoulos S, Filipova D, Baransi S, Todorović D, Lake P, Metzler D, Hilsdorf S, Schubert R, Schroeter MM, Pfitzer G. The involvement of phosphorylation of myosin phosphatase targeting subunit 1 (MYPT1) and MYPT1 isoform expression in NO/cGMP mediated differential vasoregulation of cerebral arteries compared to systemic arteries. Acta Physiol (Oxf) 2018; 224:e13079. [PMID: 29694711 DOI: 10.1111/apha.13079] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/30/2018] [Accepted: 04/17/2018] [Indexed: 12/23/2022]
Abstract
AIM Constitutive release of NO blunts intrinsic and stimulated contractile activity in cerebral arteries (CA). Here, we explored whether phosphorylation and expression levels of the PKG-sensitive, leucine zipper positive (LZ+ ) splice variants of the regulatory subunit of myosin phosphatase (MYPT1) are involved and whether its expression is associated with higher cGMP sensitivity. METHODS Vascular contractility was investigated by wire myography. Phosphorylation of MYPT1 was determined by Western blotting. RESULTS Constitutive phosphorylation of MYPT1-T696 and T853 was lower and that of S695 and S668 was higher in cerebral arteries from the circulus arteriosus (CA-w) than in femoral arteries (FA), while total MYPT1 expression was not different. In CA-w but not in FA, L-NAME lowered phosphorylation of S695/S668 and increased phosphorylation of T696/T853 and of MLC20 -S19, plus basal tone. The increase in basal tone was attenuated in CA-w and basilar arteries (BA) from heterozygous MYPT1-T696A/+ mice. Compared to FA, expression of the LZ+ -isoform was ~2-fold higher in CA-w coincident with a higher sensitivity to DEA-NONOate, cinaciguat and Y27632 in BA and 8-Br-cGMP (1 μmol/L) in pre-constricted (pCa 6.1) α-toxin permeabilized CAs. In contrast, 6-Bnz-cAMP (10 μmol/L) relaxed BA and FA similarly by ~80%. CONCLUSION Our results indicate that (i) regulation of the intrinsic contractile activity in CA involves phosphorylation of MYPT1 at T696 and S695/S668, (ii) the higher NO/cGMP/PKG sensitivity of CAs can be ascribed to the higher expression level of the LZ+ -MYPT1 isoform and (iii) relaxation by cAMP/PKA pathway is less dependent on the expression level of the LZ+ splice variants of MYPT1.
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Affiliation(s)
- L. T. Lubomirov
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
| | - S. Papadopoulos
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
| | - D. Filipova
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
| | - S. Baransi
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
| | - D. Todorović
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
| | - P. Lake
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
| | - D. Metzler
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
| | - S. Hilsdorf
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
| | - R. Schubert
- Research Division Cardiovascular Physiology; Centre for Biomedicine and Medical Technology Mannheim (CBTM); Ruprecht-Karls-University Heidelberg; Heidelberg Germany
| | - M. M. Schroeter
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
| | - G. Pfitzer
- Institute of Vegetative Physiology; University of Cologne; Cologne Germany
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15
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Wang F, Sun Y. Overexpression of Myosin Phosphatase Target Subunit 1 (MYPT1) Inhibits Tumor Progression and Metastasis of Gastric Cancer. Med Sci Monit 2018; 24:2508-2517. [PMID: 29687789 PMCID: PMC5937360 DOI: 10.12659/msm.906852] [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] [Indexed: 12/17/2022] Open
Abstract
Background Myosin phosphatase target subunit 1 (MYPT1) serves as a subgroup of myosin phosphatases, and is frequently low-expressed in human cancers. However, little is known about the effects of MYPT1 in gastric cancer (GC). Material/Methods In our study, MYPT1 expression was detected by quantitative real-time reverse transcription PCR (qRT-PCR) in GC tissues, different advanced pathological stages of GC tissues, and preoperative and postoperative patients. Kaplan-Meier analysis was used to measure the overall survival of GC patients. MYPT1 expression was analyzed by qRT-PCR and Western blot assays in GES-1 cells and GC cells. Cell proliferation, cycle, and migration and invasion abilities were detected by CCK-8, flow cytometry, and Transwell assays. E-cadherin, TIMP-2, MMP-2, MMP-9 RhoA, and p-RhoA expressions were assessed by qRT-PCR and Western blot assays in treated SNU-5 cells. Results Our results indicated that MYPT1 was down-regulated in GC tissues and cells, and is related to clinical stages and overall survival of GC. Functional research demonstrated that overexpression of MYPT1 can inhibit cell proliferation, cell cycle progression, and migration and invasion of GC cells. Many studies on mechanisms reported that overexpression of MYPT1 dramatically improved the expression levels of cell cycle-related genes (Cyclin D1 and c-myc), significantly increased epithelial marker (E-cadherin) expression, and decreased invasion-associated genes (TIMP-2 and MMP-2) expressions in SNU-5 cells. In addition, we found that MYPT1 suppressed RhoA phosphorylation. Conclusions We verified that MYPT1 inhibits GC cell proliferation and metastasis by regulating RhoA phosphorylation.
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Affiliation(s)
- Fengyong Wang
- Department of Gastrointestinal and Pancreatic Surgery, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang, China (mainland)
| | - Yuanshui Sun
- Department of Gastrointestinal and Pancreatic Surgery, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang, China (mainland)
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16
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Lyle MA, Davis JP, Brozovich FV. Regulation of Pulmonary Vascular Smooth Muscle Contractility in Pulmonary Arterial Hypertension: Implications for Therapy. Front Physiol 2017; 8:614. [PMID: 28878690 PMCID: PMC5572347 DOI: 10.3389/fphys.2017.00614] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/09/2017] [Indexed: 12/23/2022] Open
Abstract
There are two primary components that produce pulmonary arterial hypertension (PAH); aberrant structural changes (smooth muscle cell proliferation, smooth muscle cell hypertrophy, and the deposition of matrix proteins within the media of pulmonary arterial vessels), and excess vasoconstriction. However, in PAH, the target and aim of all current therapeutic agents is to reduce the contractility of the pulmonary vasculature; prostaglandins, phosphodiesterase inhibitors, guanylate cyclase stimulators, endothelin antagonists, NO inhalation and Rho kinase inhibitors all influence signaling pathways in the pulmonary vascular smooth muscle to decrease vasoconstriction, and hence, pulmonary vascular resistance (PVR). This review will therefore primarily focus on discussing the signaling pathways regulating contractility in pulmonary vascular smooth muscle, the mechanism for current treatments, as well as highlighting potential targets for the development of novel therapies.
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Affiliation(s)
- Melissa A Lyle
- Department of Cardiovascular Diseases, Mayo ClinicRochester, MN, United States
| | - Jonathan P Davis
- Department of Physiology and Cell Biology, Ohio State UniversityColumbus, OH, United States
| | - Frank V Brozovich
- Department of Cardiovascular Diseases, Mayo ClinicRochester, MN, United States
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17
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Lin S, Brozovich FV. MYPT1 isoforms expressed in HEK293T cells are differentially phosphorylated after GTPγS treatment. J Smooth Muscle Res 2017; 52:66-77. [PMID: 27725371 PMCID: PMC5321854 DOI: 10.1540/jsmr.52.66] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Agonist stimulation of smooth muscle is known to activate RhoA/Rho kinase signaling, and
Rho kinase phosphorylates the myosin targeting subunit (MYPT1) of myosin light chain (MLC)
phosphatase at Thr696 and Thr853, which inhibits the activity of MLC phosphatase to
produce a Ca2+ independent increase in MLC phosphorylation and force (Ca2+ sensitization).
Alternative mRNA splicing produces four MYPT1 isoforms, which differ by the presence or
absence of a central insert (CI) and leucine zipper (LZ). This study was designed to
determine if Rho kinase differentially phosphorylates MYPT1 isoforms. In HEK293T cells
expressing each of the four MYPT1 isoforms, we could not detect a change in Thr853 MYPT1
phosphorylation following GTPγS treatment. However, there is differential phosphorylation
of MYPT1 isoforms at Thr696; GTPγS treatment increases MYPT1 phosphorylation for the
CI+LZ- and CI-LZ- MYPT1 isoforms, but not the CI+LZ+ or CI-LZ+ MYPT1 isoforms. These data
could suggest that in smooth muscle Rho kinase differentially phosphorylates MYPT1
isoforms.
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Affiliation(s)
- Simon Lin
- Mayo Medical School, Department of Cardiovascular Disease, Rochester, MN 55905, USA
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18
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Filter JJ, Williams BC, Eto M, Shalloway D, Goldberg ML. Unfair competition governs the interaction of pCPI-17 with myosin phosphatase (PP1-MYPT1). eLife 2017; 6. [PMID: 28387646 PMCID: PMC5441869 DOI: 10.7554/elife.24665] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 03/31/2017] [Indexed: 11/30/2022] Open
Abstract
The small phosphoprotein pCPI-17 inhibits myosin light-chain phosphatase (MLCP). Current models postulate that during muscle relaxation, phosphatases other than MLCP dephosphorylate and inactivate pCPI-17 to restore MLCP activity. We show here that such hypotheses are insufficient to account for the observed rapidity of pCPI-17 inactivation in mammalian smooth muscles. Instead, MLCP itself is the critical enzyme for pCPI-17 dephosphorylation. We call the mutual sequestration mechanism through which pCPI-17 and MLCP interact inhibition by unfair competition: MLCP protects pCPI-17 from other phosphatases, while pCPI-17 blocks other substrates from MLCP’s active site. MLCP dephosphorylates pCPI-17 at a slow rate that is, nonetheless, both sufficient and necessary to explain the speed of pCPI-17 dephosphorylation and the consequent MLCP activation during muscle relaxation. DOI:http://dx.doi.org/10.7554/eLife.24665.001
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Affiliation(s)
- Joshua J Filter
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Byron C Williams
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Masumi Eto
- Department of Molecular Physiology and Biophysics, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, United States
| | - David Shalloway
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Michael L Goldberg
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
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19
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Smooth Muscle Phenotypic Diversity: Effect on Vascular Function and Drug Responses. ADVANCES IN PHARMACOLOGY 2017. [PMID: 28212802 DOI: 10.1016/bs.apha.2016.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
At its simplest resistance to blood flow is regulated by changes in the state of contraction of the vascular smooth muscle (VSM), a function of the competing activities of the myosin kinase and phosphatase determining the phosphorylation and activity of the myosin ATPase motor protein. In contrast, the vascular system of humans and other mammals is incredibly complex and highly regulated. Much of this complexity derives from phenotypic diversity within the smooth muscle, reflected in very differing power outputs and responses to signaling pathways that regulate vessel tone, presumably having evolved over the millennia to optimize vascular function and its control. The highly regulated nature of VSM tone, described as pharmacomechanical coupling, likely underlies the many classes of drugs in clinical use to alter vascular tone through activation or inhibition of these signaling pathways. This review will first describe the phenotypic diversity within VSM, followed by presentation of specific examples of how molecular diversity in signaling, myofilament, and calcium cycling proteins impacts arterial smooth muscle function and drug responses.
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20
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Characterization of isoform expression and subcellular distribution of MYPT1 in intestinal epithelial cells. Gene 2016; 588:1-6. [PMID: 27129938 DOI: 10.1016/j.gene.2016.04.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 04/07/2016] [Accepted: 04/23/2016] [Indexed: 11/21/2022]
Abstract
The regulation of intestinal epithelial permeability requires phosphorylation of myosin regulatory light chain (MLC). The phosphorylation status of MLC is regulated by myosin light chain phosphatase (MLCP) activities. The activity of the catalytic subunit of MLCP (PP1cδ) toward MLC depends on its regulatory subunit (MYPT1). In this study, we revealed the presence of two MYPT1 isoforms, full length and variant 2 in human intestinal (Caco-2) epithelial cells and isolated intestinal epithelial cells (IECs) from mice. In confluent Caco-2 cells, MYPT1 was distributed at cell-cell contacts and colocalized with F-actin. These results suggest that MYPT1 isoforms are expressed in intestinal epithelial cells and MYPT1 may be involved in the regulation of intestinal epithelial barrier function.
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21
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Reho JJ, Kenchegowda D, Asico LD, Fisher SA. A splice variant of the myosin phosphatase regulatory subunit tunes arterial reactivity and suppresses response to salt loading. Am J Physiol Heart Circ Physiol 2016; 310:H1715-24. [PMID: 27084390 DOI: 10.1152/ajpheart.00869.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 04/12/2016] [Indexed: 12/21/2022]
Abstract
The cGMP activated kinase cGK1α is targeted to its substrates via leucine zipper (LZ)-mediated heterodimerization and thereby mediates vascular smooth muscle (VSM) relaxation. One target is myosin phosphatase (MP), which when activated by cGK1α results in VSM relaxation even in the presence of activating calcium. Variants of MP regulatory subunit Mypt1 are generated by alternative splicing of the 31 nt exon 24 (E24), which, by changing the reading frame, codes for isoforms that contain or lack the COOH-terminal LZ motif (E24+/LZ-; E24-/LZ+). Expression of these isoforms is vessel specific and developmentally regulated, modulates in disease, and is proposed to confer sensitivity to nitric oxide (NO)/cGMP-mediated vasorelaxation. To test this, mice underwent Tamoxifen-inducible and smooth muscle-specific knockout of E24 (E24 cKO) after weaning. Deletion of a single allele of E24 (shift to Mypt1 LZ+) enhanced vasorelaxation of first-order mesenteric arteries (MA1) to diethylamine-NONOate (DEA/NO) and to cGMP in permeabilized and calcium-clamped arteries and lowered blood pressure. There was no further effect of deletion of both E24 alleles, indicating high sensitivity to shift of Mypt1 isoforms. However, a unique property of MA1s from homozygous E24 cKOs was significantly reduced force generation to α-adrenergic activation. Furthermore 2 wk of high-salt (4% NaCl) diet increased MA1 force generation to phenylephrine in control mice, a response that was markedly suppressed in the E24 cKO homozygotes. Thus Mypt1 E24 splice variants tune arterial reactivity and could be worthy targets for lowering vascular resistance in disease states.
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Affiliation(s)
- John J Reho
- Department of Medicine, Divisions of Cardiovascular Medicine and Nephrology, University of Maryland-Baltimore, Baltimore, Maryland
| | - Doreswamy Kenchegowda
- Department of Medicine, Divisions of Cardiovascular Medicine and Nephrology, University of Maryland-Baltimore, Baltimore, Maryland
| | - Laureano D Asico
- Department of Medicine, Divisions of Cardiovascular Medicine and Nephrology, University of Maryland-Baltimore, Baltimore, Maryland
| | - Steven A Fisher
- Department of Medicine, Divisions of Cardiovascular Medicine and Nephrology, University of Maryland-Baltimore, Baltimore, Maryland
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22
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Brozovich FV, Nicholson CJ, Degen CV, Gao YZ, Aggarwal M, Morgan KG. Mechanisms of Vascular Smooth Muscle Contraction and the Basis for Pharmacologic Treatment of Smooth Muscle Disorders. Pharmacol Rev 2016; 68:476-532. [PMID: 27037223 PMCID: PMC4819215 DOI: 10.1124/pr.115.010652] [Citation(s) in RCA: 298] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The smooth muscle cell directly drives the contraction of the vascular wall and hence regulates the size of the blood vessel lumen. We review here the current understanding of the molecular mechanisms by which agonists, therapeutics, and diseases regulate contractility of the vascular smooth muscle cell and we place this within the context of whole body function. We also discuss the implications for personalized medicine and highlight specific potential target molecules that may provide opportunities for the future development of new therapeutics to regulate vascular function.
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Affiliation(s)
- F V Brozovich
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - C J Nicholson
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - C V Degen
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - Yuan Z Gao
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - M Aggarwal
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
| | - K G Morgan
- Department of Health Sciences, Boston University, Boston, Massachusetts (C.J.N., Y.Z.G., M.A., K.G.M.); Department of Medicine, Mayo Clinic, Rochester, Minnesota (F.V.B.); and Paracelsus Medical University Salzburg, Salzburg, Austria (C.V.D.)
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23
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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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