1
|
Liang C, Aisa Z, Sun L, Zhang B. Cardiac ischemic preconditioning promotes cMyBP-C phosphorylation by inhibiting the calpain-mediated proteolysis. Exp Cell Res 2023; 433:113859. [PMID: 38000772 DOI: 10.1016/j.yexcr.2023.113859] [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: 09/10/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 11/26/2023]
Abstract
Ischemic preconditioning (IPC) has been considered as the most important mean to protect against ischemia/reperfusion (I/R) induced heart injury. It has been reported that cardiac myosin binding protein-C (cMyBP-C) phosphorylation plays an essential role in cardiac protection against I/R-induced heart injury. However, it is still obscured whether IPC-mediated cardiac protection is causally related to cMyBP-C phosphorylation and proteolysis and, if so, what the underlying mechanism is. In this study, IPC was found to increase the phosphorylation level of cMyBP-C, companying with the decreased calpain activity in the collected perfusate samples. Mechanistically, we confirmed that IPC promoted cMyBP-C phosphorylation and inhibited calpain-mediated cMyBP-C proteolysis. Moreover, inhibition of calpain activity significantly increased the phosphorylated cMyBP-C level by using calpain inhibitor (MG-101), and subsequently promoted stabilization and secretion of cMyBP-C. Functionally, adeno-associated virus (AAV)-mediated overexpression of mutated phosphorylation motif site of cMyBP-C exhibited impaired IPC-mediated cardiac protection via proteolysis of the full-length cMyBP-C protein. We concluded that IPC promoted cMyBP-C phosphorylation via inhibition of calpain-mediated proteolysis and participated in IPC-mediated protection against I/R induced heart injury.
Collapse
Affiliation(s)
- Cheng Liang
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Urumqi, China; Department 2 of Cardiology, Affiliated Hospital of Traditional Chinese Medicine of Xinjiang Medical University, Urumqi, China
| | - Zulibiya Aisa
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Urumqi, China; Department 5 of Cardiology, Affiliated Hospital of Traditional Chinese Medicine of Xinjiang Medical University, Urumqi, China
| | - Longfei Sun
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Urumqi, China; Department 4 of Cardiology, Affiliated Hospital of Traditional Chinese Medicine of Xinjiang Medical University, Urumqi, China
| | - Baojian Zhang
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Urumqi, China; Department 5 of Cardiology, Affiliated Hospital of Traditional Chinese Medicine of Xinjiang Medical University, Urumqi, China.
| |
Collapse
|
2
|
Ochala J, Lewis CTA, Beck T, Iwamoto H, Hessel AL, Campbell KS, Pyle WG. Predominant myosin superrelaxed state in canine myocardium with naturally occurring dilated cardiomyopathy. Am J Physiol Heart Circ Physiol 2023; 325:H585-H591. [PMID: 37505469 DOI: 10.1152/ajpheart.00369.2023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/12/2023] [Accepted: 07/24/2023] [Indexed: 07/29/2023]
Abstract
Dilated cardiomyopathy (DCM) is a naturally occurring heart failure condition in humans and dogs, notably characterized by a reduced contractility and ejection fraction. As the identification of its underlying cellular and molecular mechanisms remain incomplete, the aim of the present study was to assess whether the molecular motor myosin and its known relaxed conformational states are altered in DCM. For that, we dissected and skinned thin cardiac strips from left ventricle obtained from six DCM Doberman Pinschers and six nonfailing (NF) controls. We then used a combination of Mant-ATP chase experiments and X-ray diffraction to assess both energetic and structural changes of myosin. Using the Mant-ATP chase protocol, we observed that in DCM dogs, the amount of myosin molecules in the ATP-conserving conformational state, also known as superrelaxed (SRX), is significantly increased when compared with NF dogs. This alteration can be rescued by applying EMD-57033, a small molecule activating myosin. Conversely, with X-ray diffraction, we found that in DCM dogs, there is a higher proportion of myosin heads in the vicinity of actin when compared with NF dogs (1,0 to 1,1 intensity ratio). Hence, we observed an uncoupling between energetic (Mant-ATP chase) and structural (X-ray diffraction) data. Taken together, these results may indicate that in the heart of Doberman Pinschers with DCM, myosin molecules are potentially stuck in a nonsequestered but ATP-conserving SRX state, that can be counterbalanced by EMD-57033 demonstrating the potential for a myosin-centered pharmacological treatment of DCM.NEW & NOTEWORTHY The key finding of the present study is that, in left ventricles of dogs with a naturally occurring dilated cardiomyopathy, relaxed myosin molecules favor a nonsequestered superrelaxed state potentially impairing sarcomeric contractility. This alteration is rescuable by applying a small molecule activating myosin known as EMD-57033.
Collapse
Affiliation(s)
- Julien Ochala
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Thomas Beck
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hiroyuki Iwamoto
- SPring-8, Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Anthony L Hessel
- Institute of Physiology II, University of Muenster, Muenster, Germany
- Accelerated Muscle Biotechnologies, Boston, Massachusetts, United States
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky, United States
| | - W Glen Pyle
- IMPART Investigator Team, Dalhousie Medicine, Saint John, New Brunswick, Canada
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada
| |
Collapse
|
3
|
Hitsumoto T, Tsukamoto O, Matsuoka K, Li J, Liu L, Kuramoto Y, Higo S, Ogawa S, Fujino N, Yoshida S, Kioka H, Kato H, Hakui H, Saito Y, Okamoto C, Inoue H, Hyejin J, Ueda K, Segawa T, Nishimura S, Asano Y, Asanuma H, Tani A, Imamura R, Komagawa S, Kanai T, Takamura M, Sakata Y, Kitakaze M, Haruta JI, Takashima S. Restoration of Cardiac Myosin Light Chain Kinase Ameliorates Systolic Dysfunction by Reducing Superrelaxed Myosin. Circulation 2023; 147:1902-1918. [PMID: 37128901 PMCID: PMC10270284 DOI: 10.1161/circulationaha.122.062885] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 04/05/2023] [Indexed: 05/03/2023]
Abstract
BACKGROUND Cardiac-specific myosin light chain kinase (cMLCK), encoded by MYLK3, regulates cardiac contractility through phosphorylation of ventricular myosin regulatory light chain. However, the pathophysiological and therapeutic implications of cMLCK in human heart failure remain unclear. We aimed to investigate whether cMLCK dysregulation causes cardiac dysfunction and whether the restoration of cMLCK could be a novel myotropic therapy for systolic heart failure. METHODS We generated the knock-in mice (Mylk3+/fs and Mylk3fs/fs) with a familial dilated cardiomyopathy-associated MYLK3 frameshift mutation (MYLK3+/fs) that had been identified previously by us (c.1951-1G>T; p.P639Vfs*15) and the human induced pluripotent stem cell-derived cardiomyocytes from the carrier of the mutation. We also developed a new small-molecule activator of cMLCK (LEUO-1154). RESULTS Both mice (Mylk3+/fs and Mylk3fs/fs) showed reduced cMLCK expression due to nonsense-mediated messenger RNA decay, reduced MLC2v (ventricular myosin regulatory light chain) phosphorylation in the myocardium, and systolic dysfunction in a cMLCK dose-dependent manner. Consistent with this result, myocardium from the mutant mice showed an increased ratio of cardiac superrelaxation/disordered relaxation states that may contribute to impaired cardiac contractility. The phenotypes observed in the knock-in mice were rescued by cMLCK replenishment through the AAV9_MYLK3 vector. Human induced pluripotent stem cell-derived cardiomyocytes with MYLK3+/fs mutation reduced cMLCK expression by 50% and contractile dysfunction, accompanied by an increased superrelaxation/disordered relaxation ratio. CRISPR-mediated gene correction, or cMLCK replenishment by AAV9_MYLK3 vector, successfully recovered cMLCK expression, the superrelaxation/disordered relaxation ratio, and contractile dysfunction. LEUO-1154 increased human cMLCK activity ≈2-fold in the Vmax for ventricular myosin regulatory light chain phosphorylation without affecting the Km. LEUO-1154 treatment of human induced pluripotent stem cell-derived cardiomyocytes with MYLK3+/fs mutation restored the ventricular myosin regulatory light chain phosphorylation level and superrelaxation/disordered relaxation ratio and improved cardiac contractility without affecting calcium transients, indicating that the cMLCK activator acts as a myotrope. Finally, human myocardium from advanced heart failure with a wide variety of causes had a significantly lower MYLK3/PPP1R12B messenger RNA expression ratio than control hearts, suggesting an altered balance between myosin regulatory light chain kinase and phosphatase in the failing myocardium, irrespective of the causes. CONCLUSIONS cMLCK dysregulation contributes to the development of cardiac systolic dysfunction in humans. Our strategy to restore cMLCK activity could form the basis of a novel myotropic therapy for advanced systolic heart failure.
Collapse
Affiliation(s)
- Tatsuro Hitsumoto
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Osamu Tsukamoto
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Ken Matsuoka
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Junjun Li
- Department of Cardiovascular Surgery (J.L., L.L.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
| | - Li Liu
- Department of Cardiovascular Surgery (J.L., L.L.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
| | - Yuki Kuramoto
- Department of Cardiology (Y.K., S.H., S.O., H. Kioka, HY.H., S.N., Y.A., Y.S.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
| | - Shuichiro Higo
- Department of Cardiology (Y.K., S.H., S.O., H. Kioka, HY.H., S.N., Y.A., Y.S.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
| | - Shou Ogawa
- Department of Cardiology (Y.K., S.H., S.O., H. Kioka, HY.H., S.N., Y.A., Y.S.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
| | - Noboru Fujino
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kanazawa University. Kanazawa, Ishikawa, Japan (N.F., S.Y., M.T.)
| | - Shohei Yoshida
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kanazawa University. Kanazawa, Ishikawa, Japan (N.F., S.Y., M.T.)
| | - Hidetaka Kioka
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
- Department of Cardiology (Y.K., S.H., S.O., H. Kioka, HY.H., S.N., Y.A., Y.S.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
| | - Hisakazu Kato
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Hideyuki Hakui
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
- Department of Cardiology (Y.K., S.H., S.O., H. Kioka, HY.H., S.N., Y.A., Y.S.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
| | - Yuki Saito
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Chisato Okamoto
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Hijiri Inoue
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Jo Hyejin
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Kyoko Ueda
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Takatsugu Segawa
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| | - Shunsuke Nishimura
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
- Department of Cardiology (Y.K., S.H., S.O., H. Kioka, HY.H., S.N., Y.A., Y.S.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
| | - Yoshihiro Asano
- Department of Cardiology (Y.K., S.H., S.O., H. Kioka, HY.H., S.N., Y.A., Y.S.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
- Department of Genomic Medicine, National Cerebral and Cardiovascular Center, Osaka, Japan (Y.A.)
| | - Hiroshi Asanuma
- Department of Internal Medicine, Meiji University of Integrative Medicine, Nantan, Kyoto, Japan (H.A.)
| | - Akiyoshi Tani
- Compound Library Screening Center (A.T.), Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Riyo Imamura
- Drug Discovery Initiative, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan (R.I.)
| | - Shinsuke Komagawa
- Lead Explorating Units (S.K., T.K., J.-i.H.), Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Toshio Kanai
- Lead Explorating Units (S.K., T.K., J.-i.H.), Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Masayuki Takamura
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kanazawa University. Kanazawa, Ishikawa, Japan (N.F., S.Y., M.T.)
| | - Yasushi Sakata
- Department of Cardiology (Y.K., S.H., S.O., H. Kioka, HY.H., S.N., Y.A., Y.S.), Osaka University Graduate School of Medicine. Suita, Osaka, Japan
| | | | - Jun-ichi Haruta
- Lead Explorating Units (S.K., T.K., J.-i.H.), Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Seiji Takashima
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine/Frontier Biosciences, Suita, Osaka, Japan (T.H., O.T., K.M., H. Kioka, H. Kato, H.H., Y.S., C.O., H.I., J.H., K.U., T.S., S.N., S.T.)
| |
Collapse
|
4
|
Martin AA, Thompson BR, Hahn D, Angulski ABB, Hosny N, Cohen H, Metzger JM. Cardiac Sarcomere Signaling in Health and Disease. Int J Mol Sci 2022; 23:16223. [PMID: 36555864 PMCID: PMC9782806 DOI: 10.3390/ijms232416223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
The cardiac sarcomere is a triumph of biological evolution wherein myriad contractile and regulatory proteins assemble into a quasi-crystalline lattice to serve as the central point upon which cardiac muscle contraction occurs. This review focuses on the many signaling components and mechanisms of regulation that impact cardiac sarcomere function. We highlight the roles of the thick and thin filament, both as necessary structural and regulatory building blocks of the sarcomere as well as targets of functionally impactful modifications. Currently, a new focus emerging in the field is inter-myofilament signaling, and we discuss here the important mediators of this mechanism, including myosin-binding protein C and titin. As the understanding of sarcomere signaling advances, so do the methods with which it is studied. This is reviewed here through discussion of recent live muscle systems in which the sarcomere can be studied under intact, physiologically relevant conditions.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Joseph M. Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| |
Collapse
|
5
|
Mohan IK, Baba KSSS, Iyyapu R, Thirumalasetty S, Satish OS. Advances in congestive heart failure biomarkers. Adv Clin Chem 2022; 112:205-248. [PMID: 36642484 DOI: 10.1016/bs.acc.2022.09.005] [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: 11/06/2022]
Abstract
Congestive heart failure (CHF) is the leading cause of morbidity and mortality in the elderly worldwide. Although many biomarkers associated with in heart failure, these are generally prognostic and identify patients with moderate and severe disease. Unfortunately, the role of biomarkers in decision making for early and advanced heart failure remains largely unexplored. Previous studies suggest the natriuretic peptides have the potential to improve the diagnosis of heart failure, but they still have significant limitations related to cut-off values. Although some promising cardiac biomarkers have emerged, comprehensive data from large cohort studies is lacking. The utility of multiple biomarkers that reflect various pathophysiologic pathways are increasingly being explored in heart failure risk stratification and to diagnose disease conditions promptly and accurately. MicroRNAs serve as mediators and/or regulators of renin-angiotensin-induced cardiac remodeling by directly targeting enzymes, receptors and signaling molecules. The role of miRNA in HF diagnosis is a promising area of research and further exploration may offer both diagnostic and prognostic applications and phenotype-specific targets. In this review, we provide insight into the classification of different biochemical and molecular markers associated with CHF, examine clinical usefulness in CHF and highlight the most clinically relevant.
Collapse
Affiliation(s)
| | - K S S Sai Baba
- Nizam's Institute of Medical Sciences, Panjagutta, Hyderabad, Telangana, India
| | - Rohit Iyyapu
- Katuri Medical College & Hospital, Guntur, Andhra Pradesh, India
| | | | - O Sai Satish
- Nizam's Institute of Medical Sciences, Panjagutta, Hyderabad, Telangana, India
| |
Collapse
|
6
|
Kazmierczak K, Liang J, Gomez-Guevara M, Szczesna-Cordary D. Functional comparison of phosphomimetic S15D and T160D mutants of myosin regulatory light chain exchanged in cardiac muscle preparations of HCM and WT mice. Front Cardiovasc Med 2022; 9:988066. [PMID: 36204565 PMCID: PMC9530205 DOI: 10.3389/fcvm.2022.988066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/31/2022] [Indexed: 12/30/2022] Open
Abstract
In this study, we investigated the rescue potential of two phosphomimetic mutants of the myosin regulatory light chain (RLC, MYL2 gene), S15D, and T160D RLCs. S15D-RLC mimics phosphorylation of the established serine-15 site of the human cardiac RLC. T160D-RLC mimics the phosphorylation of threonine-160, identified by computational analysis as a high-score phosphorylation site of myosin RLC. Cardiac myosin and left ventricular papillary muscle (LVPM) fibers were isolated from a previously generated model of hypertrophic cardiomyopathy (HCM), Tg-R58Q, and Tg-wild-type (WT) mice. Muscle specimens were first depleted of endogenous RLC and then reconstituted with recombinant human cardiac S15D and T160D phosphomimetic RLCs. Preparations reconstituted with recombinant human cardiac WT-RLC and R58Q-RLC served as controls. Mouse myosins were then tested for the actin-activated myosin ATPase activity and LVPM fibers for the steady-state force development and Ca2+-sensitivity of force. The data showed that S15D-RLC significantly increased myosin ATPase activity compared with T160D-RLC or WT-RLC reconstituted preparations. The two S15D and T160D phosphomimetic RLCs were able to rescue Vmax of Tg-R58Q myosin reconstituted with recombinant R58Q-RLC, but the effect of S15D-RLC was more pronounced than T160D-RLC. Low tension observed for R58Q-RLC reconstituted LVPM from Tg-R58Q mice was equally rescued by both phosphomimetic RLCs. In the HCM Tg-R58Q myocardium, the S15D-RLC caused a shift from the super-relaxed (SRX) state to the disordered relaxed (DRX) state, and the number of heads readily available to interact with actin and produce force was increased. At the same time, T160D-RLC stabilized the SRX state at a level similar to R58Q-RLC reconstituted fibers. We report here on the functional superiority of the established S15 phospho-site of the human cardiac RLC vs. C-terminus T160-RLC, with S15D-RLC showing therapeutic potential in mitigating a non-canonical HCM behavior underlined by hypocontractile behavior of Tg-R58Q myocardium.
Collapse
|
7
|
Bang ML, Bogomolovas J, Chen J. Understanding the molecular basis of cardiomyopathy. Am J Physiol Heart Circ Physiol 2022; 322:H181-H233. [PMID: 34797172 PMCID: PMC8759964 DOI: 10.1152/ajpheart.00562.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/03/2023]
Abstract
Inherited cardiomyopathies are a major cause of mortality and morbidity worldwide and can be caused by mutations in a wide range of proteins located in different cellular compartments. The present review is based on Dr. Ju Chen's 2021 Robert M. Berne Distinguished Lectureship of the American Physiological Society Cardiovascular Section, in which he provided an overview of the current knowledge on the cardiomyopathy-associated proteins that have been studied in his laboratory. The review provides a general summary of the proteins in different compartments of cardiomyocytes associated with cardiomyopathies, with specific focus on the proteins that have been studied in Dr. Chen's laboratory.
Collapse
Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research (IRGB), National Research Council (CNR), Milan Unit, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano (Milan), Italy
| | - Julius Bogomolovas
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
| | - Ju Chen
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
| |
Collapse
|
8
|
Regulation of myosin light-chain phosphorylation and its roles in cardiovascular physiology and pathophysiology. Hypertens Res 2022; 45:40-52. [PMID: 34616031 DOI: 10.1038/s41440-021-00733-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/19/2021] [Accepted: 07/08/2021] [Indexed: 01/22/2023]
Abstract
The regulation of muscle contraction is a critical function in the cardiovascular system, and abnormalities may be life-threatening or cause illness. The common basic mechanism in muscle contraction is the interaction between the protein filaments myosin and actin. Although this interaction is primarily regulated by intracellular Ca2+, the primary targets and intracellular signaling pathways differ in vascular smooth muscle and cardiac muscle. Phosphorylation of the myosin regulatory light chain (RLC) is a primary molecular switch for smooth muscle contraction. The equilibrium between phosphorylated and unphosphorylated RLC is dynamically achieved through two enzymes, myosin light chain kinase, a Ca2+-dependent enzyme, and myosin phosphatase, which modifies the Ca2+ sensitivity of contractions. In cardiac muscle, the primary target protein for Ca2+ is troponin C on thin filaments; however, RLC phosphorylation also plays a modulatory role in contraction. This review summarizes recent advances in our understanding of the regulation, physiological function, and pathophysiological involvement of RLC phosphorylation in smooth and cardiac muscles.
Collapse
|
9
|
Sitbon YH, Diaz F, Kazmierczak K, Liang J, Wangpaichitr M, Szczesna-Cordary D. Cardiomyopathic mutations in essential light chain reveal mechanisms regulating the super relaxed state of myosin. THE JOURNAL OF GENERAL PHYSIOLOGY 2021; 153:212172. [PMID: 34014247 PMCID: PMC8142263 DOI: 10.1085/jgp.202012801] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 04/06/2021] [Accepted: 04/27/2021] [Indexed: 12/14/2022]
Abstract
In this study, we assessed the super relaxed (SRX) state of myosin and sarcomeric protein phosphorylation in two pathological models of cardiomyopathy and in a near-physiological model of cardiac hypertrophy. The cardiomyopathy models differ in disease progression and severity and express the hypertrophic (HCM-A57G) or restrictive (RCM-E143K) mutations in the human ventricular myosin essential light chain (ELC), which is encoded by the MYL3 gene. Their effects were compared with near-physiological heart remodeling, represented by the N-terminally truncated ELC (Δ43 ELC mice), and with nonmutated human ventricular WT-ELC mice. The HCM-A57G and RCM-E143K mutations had antagonistic effects on the ATP-dependent myosin energetic states, with HCM-A57G cross-bridges fostering the disordered relaxed (DRX) state and the RCM-E143K model favoring the energy-conserving SRX state. The HCM-A57G model promoted the switch from the SRX to DRX state and showed an ∼40% increase in myosin regulatory light chain (RLC) phosphorylation compared with the RLC of normal WT-ELC myocardium. On the contrary, the RCM-E143K–associated stabilization of the SRX state was accompanied by an approximately twofold lower level of myosin RLC phosphorylation compared with the RLC of WT-ELC. Upregulation of RLC phosphorylation was also observed in Δ43 versus WT-ELC hearts, and the Δ43 myosin favored the energy-saving SRX conformation. The two disease variants also differently affected the duration of force transients, with shorter (HCM-A57G) or longer (RCM-E143K) transients measured in electrically stimulated papillary muscles from these pathological models, while no changes were displayed by Δ43 fibers. We propose that the N terminus of ELC (N-ELC), which is missing in the hearts of Δ43 mice, works as an energetic switch promoting the SRX-to-DRX transition and contributing to the regulation of myosin RLC phosphorylation in full-length ELC mice by facilitating or sterically blocking RLC phosphorylation in HCM-A57G and RCM-E143K hearts, respectively.
Collapse
Affiliation(s)
- Yoel H Sitbon
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL
| | - Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL
| | - Katarzyna Kazmierczak
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL
| | - Jingsheng Liang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL
| | | | - Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL
| |
Collapse
|
10
|
Regulatory Light Chains in Cardiac Development and Disease. Int J Mol Sci 2021; 22:ijms22094351. [PMID: 33919432 PMCID: PMC8122660 DOI: 10.3390/ijms22094351] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/14/2021] [Accepted: 04/17/2021] [Indexed: 12/18/2022] Open
Abstract
The role of regulatory light chains (RLCs) in cardiac muscle function has been elucidated progressively over the past decade. The RLCs are among the earliest expressed markers during cardiogenesis and persist through adulthood. Failing hearts have shown reduced RLC phosphorylation levels and that restoring baseline levels of RLC phosphorylation is necessary for generating optimal force of muscle contraction. The signalling mechanisms triggering changes in RLC phosphorylation levels during disease progression remain elusive. Uncovering this information may provide insights for better management of heart failure patients. Given the cardiac chamber-specific expression of RLC isoforms, ventricular RLCs have facilitated the identification of mature ventricular cardiomyocytes, opening up possibilities of regenerative medicine. This review consolidates the standing of RLCs in cardiac development and disease and highlights knowledge gaps and potential therapeutic advancements in targeting RLCs.
Collapse
|
11
|
Solís C, Solaro RJ. Novel insights into sarcomere regulatory systems control of cardiac thin filament activation. J Gen Physiol 2021; 153:211903. [PMID: 33740037 PMCID: PMC7988513 DOI: 10.1085/jgp.202012777] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/23/2021] [Indexed: 12/11/2022] Open
Abstract
Our review focuses on sarcomere regulatory mechanisms with a discussion of cardiac-specific modifications to the three-state model of thin filament activation from a blocked to closed to open state. We discuss modulation of these thin filament transitions by Ca2+, by crossbridge interactions, and by thick filament–associated proteins, cardiac myosin–binding protein C (cMyBP-C), cardiac regulatory light chain (cRLC), and titin. Emerging evidence supports the idea that the cooperative activation of the thin filaments despite a single Ca2+ triggering regulatory site on troponin C (cTnC) cannot be considered in isolation of other functional domains of the sarcomere. We discuss long- and short-range interactions among these domains with the regulatory units of thin filaments, including proteins at the barbed end at the Z-disc and the pointed end near the M-band. Important to these discussions is the ever-increasing understanding of the role of cMyBP-C, cRLC, and titin filaments. Detailed knowledge of these control processes is critical to the understanding of mechanisms sustaining physiological cardiac state with varying hemodynamic load, to better defining genetic and acquired cardiac disorders, and to developing targets for therapies at the level of the sarcomeres.
Collapse
Affiliation(s)
- Christopher Solís
- University of Illinois at Chicago, College of Medicine, Department of Physiology and Biophysics and Center for Cardiovascular Research, Chicago, IL
| | - R John Solaro
- University of Illinois at Chicago, College of Medicine, Department of Physiology and Biophysics and Center for Cardiovascular Research, Chicago, IL
| |
Collapse
|
12
|
Pagoulatou S, Rommel KP, Kresoja KP, von Roeder M, Lurz P, Thiele H, Bikia V, Rovas G, Adamopoulos D, Stergiopulos N. In vivo application and validation of a novel noninvasive method to estimate the end-systolic elastance. Am J Physiol Heart Circ Physiol 2021; 320:H1554-H1564. [PMID: 33606586 DOI: 10.1152/ajpheart.00703.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Accurate assessment of the left ventricular (LV) systolic function is indispensable in the clinic. However, estimation of a precise index of cardiac contractility, i.e., the end-systolic elastance (Ees), is invasive and cannot be established as clinical routine. The aim of this work was to present and validate a methodology that allows for the estimation of Ees from simple and readily available noninvasive measurements. The method is based on a validated model of the cardiovascular system and noninvasive data from arm-cuff pressure and routine echocardiography to render the model patient-specific. Briefly, the algorithm first uses the measured aortic flow as model input and optimizes the properties of the arterial system model to achieve correct prediction of the patient's peripheral pressure. In a second step, the personalized arterial system is coupled with the cardiac model (time-varying elastance model) and the LV systolic properties, including Ees, are tuned to predict accurately the aortic flow waveform. The algorithm was validated against invasive measurements of Ees (multiple pressure-volume loop analysis) taken from n = 10 patients with heart failure with preserved ejection fraction and n = 9 patients without heart failure. Invasive measurements of Ees (median = 2.4 mmHg/mL, range = [1.0, 5.0] mmHg/mL) agreed well with method predictions (normalized root mean square error = 9%, ρ = 0.89, bias = -0.1 mmHg/mL, and limits of agreement = [-0.9, 0.6] mmHg/mL). This is a promising first step toward the development of a valuable tool that can be used by clinicians to assess systolic performance of the LV in the critically ill.NEW & NOTEWORTHY In this study, we present a novel model-based method to estimate the left ventricular (LV) end-systolic elastance (Ees) according to measurement of the patient's arm-cuff pressure and a routine echocardiography examination. The proposed method was validated in vivo against invasive multiple-loop measurements of Ees, achieving high correlation and low bias. This tool could be most valuable for clinicians to assess the cardiovascular health of critically ill patients.
Collapse
Affiliation(s)
- Stamatia Pagoulatou
- Laboratory of Hemodynamics and Cardiovascular Technology, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Karl-Philipp Rommel
- Department of Cardiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany.,Cardiology Department, Geneva University Hospitals, Geneva, Switzerland
| | - Karl-Patrik Kresoja
- Department of Cardiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany.,Cardiology Department, Geneva University Hospitals, Geneva, Switzerland
| | - Maximilian von Roeder
- Department of Cardiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany.,Cardiology Department, Geneva University Hospitals, Geneva, Switzerland
| | - Philipp Lurz
- Department of Cardiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany.,Cardiology Department, Geneva University Hospitals, Geneva, Switzerland
| | - Holger Thiele
- Department of Cardiology, Heart Center Leipzig at University of Leipzig, Leipzig, Germany.,Cardiology Department, Geneva University Hospitals, Geneva, Switzerland
| | - Vasiliki Bikia
- Laboratory of Hemodynamics and Cardiovascular Technology, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Georgios Rovas
- Laboratory of Hemodynamics and Cardiovascular Technology, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | | | - Nikolaos Stergiopulos
- Laboratory of Hemodynamics and Cardiovascular Technology, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| |
Collapse
|
13
|
Zhang J, Wang L, Kazmierczak K, Yun H, Szczesna-Cordary D, Kawai M. Hypertrophic cardiomyopathy associated E22K mutation in myosin regulatory light chain decreases calcium-activated tension and stiffness and reduces myofilament Ca 2+ sensitivity. FEBS J 2021; 288:4596-4613. [PMID: 33548158 DOI: 10.1111/febs.15753] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 12/11/2020] [Accepted: 02/04/2021] [Indexed: 11/30/2022]
Abstract
We investigated the mechanisms associated with E22K mutation in myosin regulatory light chain (RLC), found to cause hypertrophic cardiomyopathy (HCM) in humans and mice. Specifically, we characterized the mechanical profiles of papillary muscle fibers from transgenic mice expressing human ventricular RLC wild-type (Tg-WT) or E22K mutation (Tg-E22K). Because the two mouse models expressed different amounts of transgene, the B6SJL mouse line (NTg) was used as an additional control. Mechanical experiments were carried out on Ca2+ - and ATP-activated fibers and in rigor. Sinusoidal analysis was performed to elucidate the effect of E22K on tension and stiffness during activation/rigor, tension-pCa, and myosin cross-bridge (CB) kinetics. We found significant reductions in active tension (by 54%) and stiffness (active by 40% and rigor by 54%). A decrease in the Ca2+ sensitivity of tension (by ∆pCa ~ 0.1) was observed in Tg-E22K compared with Tg-WT fibers. The apparent (=measured) rate constant of exponential process B (2πb: force generation step) was not affected by E22K, but the apparent rate constant of exponential process C (2πc: CB detachment step) was faster in Tg-E22K compared with Tg-WT fibers. Both 2πb and 2πc were smaller in NTg than in Tg-WT fibers, suggesting a kinetic difference between the human and mouse RLC. Our results of E22K-induced reduction in myofilament stiffness and tension suggest that the main effect of this mutation was to disturb the interaction of RLC with the myosin heavy chain and impose structural abnormalities in the lever arm of myosin CB. When placed in vivo, the E22K mutation is expected to result in reduced contractility and decreased cardiac output whereby leading to HCM. SUB-DISCIPLINE Bioenergetics. DATABASE The data that support the findings of this study are available from the corresponding authors upon reasonable request. ANIMAL PROTOCOL BK20150353 (Soochow University). RESEARCH GOVERNANCE School of Nursing: Hua-Gang Hu: seuboyh@163.com; Soochow University: Chen Ge chge@suda.edu.cn.
Collapse
Affiliation(s)
- Jiajia Zhang
- School of Nursing, Medical College, Soochow University, Suzhou, China
| | - Li Wang
- School of Nursing, Medical College, Soochow University, Suzhou, China
| | | | - Hang Yun
- School of Nursing, Medical College, Soochow University, Suzhou, China
| | | | - Masataka Kawai
- Department of Anatomy and Cell Biology, University of Iowa, IA, USA
| |
Collapse
|
14
|
Wang S, Wang H, Su X, Liu B, Wang L, Yan H, Mao S, Huang H, Huang C, Cheng M, Wu G. β-adrenergic activation may promote myosin light chain kinase degradation through calpain in pressure overload-induced cardiac hypertrophy: β-adrenergic activation results in MLCK degradation. Biomed Pharmacother 2020; 129:110438. [PMID: 32768940 DOI: 10.1016/j.biopha.2020.110438] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/13/2020] [Accepted: 06/17/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND β-adrenergic activation is able to exacerbate cardiac hypertrophy. Myosin light chain kinase (MLCK) and its phosphorylated substrate, phospho-myosin light chain 2 (p-MLC2), play vital roles in regulating cardiac hypertrophy. However, it is not yet clear whether there is a relationship between β-adrenergic activation and MLCK in the progression of cardiac hypertrophy. Therefore, we explored this relationship and the underlying mechanisms in this work. METHODS Cardiac hypertrophy and cardiomyocyte hypertrophy were induced by pressure overload and isoproterenol (ISO) stimulation, respectively. Echocardiography, histological analysis, immunofluorescence and qRT-PCR were used to confirm the successful establishment of the models. A β-blocker (metoprolol) and a calpain inhibitor (calpeptin) were administered to inhibit β-adrenergic activity in rats and calpain in cardiomyocytes, respectively. The protein expression levels of MLCK, myosin light chain 2 (MLC2), p-MLC2, myosin phosphatase 2 (MYPT2), calmodulin (CaM) and calpain were measured using western blotting. A cleavage assay was performed to assess the degradation of recombinant human MLCK by recombinant human calpain. RESULTS The β-blocker alleviated cardiac hypertrophy and dysfunction, increased MLCK and MLC2 phosphorylation and decreased calpain expression in pressure overload-induced cardiac hypertrophy. Additionally, the calpain inhibitor calpeptin attenuated cardiomyocyte hypertrophy, upregulated MLCK and p-MLC2 and reduced MLCK degradation in ISO-induced cardiomyocyte hypertrophy. Recombinant human calpain degraded recombinant human MLCK in vitro in concentration- and time-dependent manners, and this degradation was inhibited by the calpain inhibitor calpeptin. CONCLUSION Our study suggested that β-adrenergic activation may promote the degradation of MLCK through calpain in pressure overload-induced cardiac hypertrophy.
Collapse
Affiliation(s)
- Shun Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Haixiong Wang
- Department of Cardiology, Shanxi Cardiovascular Hospital, Taiyuan, 030001, China
| | - Xiaoling Su
- Department of Cardiology, Qinghai Provincial People's Hospital, Xining, 810007, China
| | - Beilei Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Le Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Hui Yan
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Shuai Mao
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - He Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Mian Cheng
- Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Gang Wu
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China; Department of Cardiology, Ezhou Hospital, Renmin Hospital of Wuhan University, Ezhou, 436000, China.
| |
Collapse
|
15
|
Sevrieva IR, Brandmeier B, Ponnam S, Gautel M, Irving M, Campbell KS, Sun YB, Kampourakis T. Cardiac myosin regulatory light chain kinase modulates cardiac contractility by phosphorylating both myosin regulatory light chain and troponin I. J Biol Chem 2020; 295:4398-4410. [PMID: 32086378 PMCID: PMC7135997 DOI: 10.1074/jbc.ra119.011945] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/14/2020] [Indexed: 12/14/2022] Open
Abstract
Heart muscle contractility and performance are controlled by posttranslational modifications of sarcomeric proteins. Although myosin regulatory light chain (RLC) phosphorylation has been studied extensively in vitro and in vivo, the precise role of cardiac myosin light chain kinase (cMLCK), the primary kinase acting upon RLC, in the regulation of cardiomyocyte contractility remains poorly understood. In this study, using recombinantly expressed and purified proteins, various analytical methods, in vitro and in situ kinase assays, and mechanical measurements in isolated ventricular trabeculae, we demonstrate that human cMLCK is not a dedicated kinase for RLC but can phosphorylate other sarcomeric proteins with well-characterized regulatory functions. We show that cMLCK specifically monophosphorylates Ser23 of human cardiac troponin I (cTnI) in isolation and in the trimeric troponin complex in vitro and in situ in the native environment of the muscle myofilament lattice. Moreover, we observed that human cMLCK phosphorylates rodent cTnI to a much smaller extent in vitro and in situ, suggesting species-specific adaptation of cMLCK. Although cMLCK treatment of ventricular trabeculae exchanged with rat or human troponin increased their cross-bridge kinetics, the increase in sensitivity of myofilaments to calcium was significantly blunted by human TnI, suggesting that human cTnI phosphorylation by cMLCK modifies the functional consequences of RLC phosphorylation. We propose that cMLCK-mediated phosphorylation of TnI is functionally significant and represents a critical signaling pathway that coordinates the regulatory states of thick and thin filaments in both physiological and potentially pathophysiological conditions of the heart.
Collapse
Affiliation(s)
- Ivanka R Sevrieva
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Birgit Brandmeier
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Saraswathi Ponnam
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Mathias Gautel
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Malcolm Irving
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Kenneth S Campbell
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536-0298
| | - Yin-Biao Sun
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| | - Thomas Kampourakis
- Randall Centre for Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| |
Collapse
|
16
|
Wadthaisong M, Witayavanitkul N, Bupha‐Intr T, Wattanapermpool J, de Tombe PP. Chronic high-dose testosterone treatment: impact on rat cardiac contractile biology. Physiol Rep 2019; 7:e14192. [PMID: 31353833 PMCID: PMC6661270 DOI: 10.14814/phy2.14192] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 07/09/2019] [Indexed: 01/28/2023] Open
Abstract
Androgen therapy provides cardiovascular benefits for hypogonadism. However, myocardial hypertrophy, fibrosis, and infarction have been reported in testosterone or androgenic anabolic steroid abuse. Therefore, better understanding of the factors leading to adverse results of androgen abuse is needed. The aim of the present study was to examine the impact of high dose of androgen treatment on cardiac biology, and whether exposure duration modulates this response. Male rats were treated with 10 mg/kg testosterone, three times a week, for either 4 or 12 weeks; vehicle injections served as controls. Four weeks of testosterone treatment induced an increase in ventricular wall thickness, indicative of concentric hypertrophy, as well as increased ejection fraction; in contrast, both parameters were blunted following 12 weeks of high-dose testosterone treatment. Cardiac myocyte contractile parameters were assessed in isolated electrically stimulated myocytes (sarcomere and intracellular calcium dynamics), and in chemically permeabilized isolated myocardium (myofilament force development and tension-cost). High-dose testosterone treatment for 4 weeks was associated with increased myocyte contractile parameters, while 12 weeks treatment induced significant depression of these parameters, mirroring the cardiac pump function results. In conclusion, chronic administration of high-dose testosterone initially induces increased cardiac function. However, this initial beneficial impact is followed by significant depression of cardiac pump function, myocyte contractility, and cardiac myofilament function. Our results indicate that chronic high-testosterone usage is of limited use and may, instead, induce significant cardiac dysfunction.
Collapse
Affiliation(s)
- Munthana Wadthaisong
- Department of Physiology, Faculty of ScienceMahidol UniversityBangkokThailand
- Department of Cell and Molecular PhysiologyLoyola University Chicago Health Sciences DivisionMaywoodIllinois
| | - Namthip Witayavanitkul
- Department of Physiology, Faculty of ScienceMahidol UniversityBangkokThailand
- Department of Cell and Molecular PhysiologyLoyola University Chicago Health Sciences DivisionMaywoodIllinois
| | - Tepmanas Bupha‐Intr
- Department of Physiology, Faculty of ScienceMahidol UniversityBangkokThailand
| | | | - Pieter P. de Tombe
- Department of Cell and Molecular PhysiologyLoyola University Chicago Health Sciences DivisionMaywoodIllinois
- Department of Physiology and BiophysicsUniversity of Illinois at ChicagoChicagoIllinois
| |
Collapse
|
17
|
Yadav S, Yuan CC, Kazmierczak K, Liang J, Huang W, Takeuchi LM, Kanashiro-Takeuchi RM, Szczesna-Cordary D. Therapeutic potential of AAV9-S15D-RLC gene delivery in humanized MYL2 mouse model of HCM. J Mol Med (Berl) 2019; 97:1033-1047. [PMID: 31101927 DOI: 10.1007/s00109-019-01791-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 04/24/2019] [Accepted: 05/01/2019] [Indexed: 12/15/2022]
Abstract
Familial hypertrophic cardiomyopathy (HCM) is an autosomal dominant disorder characterized by ventricular hypertrophy, myofibrillar disarray, and fibrosis, and is primarily caused by mutations in sarcomeric genes. With no definitive cure for HCM, there is an urgent need for the development of novel preventive and reparative therapies. This study is focused on aspartic acid-to-valine (D166V) mutation in the myosin regulatory light chain, RLC (MYL2 gene), associated with a malignant form of HCM. Since myosin RLC phosphorylation is critical for normal cardiac function, we aimed to exploit this post-translational modification via phosphomimetic-RLC gene therapy. We hypothesized that mimicking/modulating cardiac RLC phosphorylation in non-phosphorylatable D166V myocardium would improve heart function of HCM-D166V mice. Adeno-associated virus, serotype-9 (AAV9) was used to deliver phosphomimetic human RLC variant with serine-to-aspartic acid substitution at Ser15-RLC phosphorylation site (S15D-RLC) into the hearts of humanized HCM-D166V mice. Improvement of heart function was monitored by echocardiography, invasive hemodynamics (PV-loops) and muscle contractile mechanics. A significant increase in cardiac output and stroke work and a decrease in relaxation constant, Tau, shown to be prolonged in HCM mice, were observed in AAV- vs. PBS-injected HCM mice. Strain analysis showed enhanced myocardial longitudinal shortening in AAV-treated vs. control mice. In addition, increased maximal contractile force was observed in skinned papillary muscles from AAV-injected HCM hearts. Our data suggest that myosin RLC phosphorylation may have important translational implications for the treatment of RLC mutations-induced HCM and possibly play a role in other disease settings accompanied by depressed Ser15-RLC phosphorylation. KEY MESSAGES: HCM-D166V mice show decreased RLC phosphorylation and decompensated function. AAV9-S15D-RLC gene therapy in HCM-D166V mice, but not in WT-RLC, results in improved heart performance. Global longitudinal strain analysis shows enhanced contractility in AAV vs controls. Increased systolic and diastolic function is paralleled by higher contractile force. Phosphomimic S15D-RLC has a therapeutic potential for HCM.
Collapse
Affiliation(s)
- Sunil Yadav
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Chen-Ching Yuan
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Katarzyna Kazmierczak
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Jingsheng Liang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Wenrui Huang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Lauro M Takeuchi
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Rosemeire M Kanashiro-Takeuchi
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.,Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| |
Collapse
|
18
|
Yadav S, Sitbon YH, Kazmierczak K, Szczesna-Cordary D. Hereditary heart disease: pathophysiology, clinical presentation, and animal models of HCM, RCM, and DCM associated with mutations in cardiac myosin light chains. Pflugers Arch 2019; 471:683-699. [PMID: 30706179 DOI: 10.1007/s00424-019-02257-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/26/2018] [Accepted: 01/13/2019] [Indexed: 02/07/2023]
Abstract
Genetic cardiomyopathies, a group of cardiovascular disorders based on ventricular morphology and function, are among the leading causes of morbidity and mortality worldwide. Such genetically driven forms of hypertrophic (HCM), dilated (DCM), and restrictive (RCM) cardiomyopathies are chronic, debilitating diseases that result from biomechanical defects in cardiac muscle contraction and frequently progress to heart failure (HF). Locus and allelic heterogeneity, as well as clinical variability combined with genetic and phenotypic overlap between different cardiomyopathies, have challenged proper clinical prognosis and provided an incentive for identification of pathogenic variants. This review attempts to provide an overview of inherited cardiomyopathies with a focus on their genetic etiology in myosin regulatory (RLC) and essential (ELC) light chains, which are EF-hand protein family members with important structural and regulatory roles. From the clinical discovery of cardiomyopathy-linked light chain mutations in patients to an array of exploratory studies in animals, and reconstituted and recombinant systems, we have summarized the current state of knowledge on light chain mutations and how they induce physiological disease states via biochemical and biomechanical alterations at the molecular, tissue, and organ levels. Cardiac myosin RLC phosphorylation and the N-terminus ELC have been discussed as two important emerging modalities with important implications in the regulation of myosin motor function, and thus cardiac performance. A comprehensive understanding of such triggers is absolutely necessary for the development of target-specific rescue strategies to ameliorate or reverse the effects of myosin light chain-related inherited cardiomyopathies.
Collapse
MESH Headings
- Animals
- Cardiomyopathy, Dilated/etiology
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/pathology
- Cardiomyopathy, Hypertrophic/etiology
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/pathology
- Cardiomyopathy, Restrictive/etiology
- Cardiomyopathy, Restrictive/genetics
- Cardiomyopathy, Restrictive/pathology
- Disease Models, Animal
- Humans
- Mutation
- Myosin Light Chains/genetics
Collapse
Affiliation(s)
- Sunil Yadav
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL, 33136, USA
| | - Yoel H Sitbon
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL, 33136, USA
| | - Katarzyna Kazmierczak
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL, 33136, USA
| | - Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL, 33136, USA.
| |
Collapse
|
19
|
Yadav S, Kazmierczak K, Liang J, Sitbon YH, Szczesna-Cordary D. Phosphomimetic-mediated in vitro rescue of hypertrophic cardiomyopathy linked to R58Q mutation in myosin regulatory light chain. FEBS J 2018; 286:151-168. [PMID: 30430732 DOI: 10.1111/febs.14702] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 10/03/2018] [Accepted: 11/13/2018] [Indexed: 12/16/2022]
Abstract
Myosin regulatory light chain (RLC) phosphorylation is important for cardiac muscle mechanics/function as well as for the Ca2+ -troponin/tropomyosin regulation of muscle contraction. This study focuses on the arginine to glutamine (R58Q) substitution in the human ventricular RLC (MYL2 gene), linked to malignant hypertrophic cardiomyopathy in humans and causing severe functional abnormalities in transgenic (Tg) R58Q mice, including inhibition of cardiac RLC phosphorylation. Using a phosphomimic recombinant RLC variant where Ser-15 at the phosphorylation site was substituted with aspartic acid (S15D) and placed in the background of R58Q, we aimed to assess whether we could rescue/mitigate R58Q-induced structural/functional abnormalities in vitro. We show rescue of several R58Q-exerted adverse phenotypes in S15D-R58Q-reconstituted porcine cardiac muscle preparations. A low level of maximal isometric force observed for R58Q- versus WT-reconstituted fibers was restored by S15D-R58Q. Significant beneficial effects were also observed on the Vmax of actin-activated myosin ATPase activity in S15D-R58Q versus R58Q-reconstituted myosin, along with its binding to fluorescently labeled actin. We also report that R58Q promotes the OFF state of myosin, both in reconstituted porcine fibers and in Tg mouse papillary muscles, thereby stabilizing the super-relaxed state (SRX) of myosin, characterized by a very low ATP turnover rate. Experiments in S15D-R58Q-reconstituted porcine fibers showed a mild destabilization of the SRX state, suggesting an S15D-mediated shift in disordered-relaxed (DRX)↔SRX equilibrium toward the DRX state of myosin. Our study shows that S15D-phosphomimic can be used as a potential rescue strategy to abrogate/alleviate the RLC mutation-induced phenotypes and is a likely candidate for therapeutic intervention in HCM patients.
Collapse
Affiliation(s)
- Sunil Yadav
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, FL, USA
| | - Katarzyna Kazmierczak
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, FL, USA
| | - Jingsheng Liang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, FL, USA
| | - Yoel H Sitbon
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, FL, USA
| | - Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, FL, USA
| |
Collapse
|
20
|
Wang L, Geist J, Grogan A, Hu LYR, Kontrogianni-Konstantopoulos A. Thick Filament Protein Network, Functions, and Disease Association. Compr Physiol 2018; 8:631-709. [PMID: 29687901 DOI: 10.1002/cphy.c170023] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sarcomeres consist of highly ordered arrays of thick myosin and thin actin filaments along with accessory proteins. Thick filaments occupy the center of sarcomeres where they partially overlap with thin filaments. The sliding of thick filaments past thin filaments is a highly regulated process that occurs in an ATP-dependent manner driving muscle contraction. In addition to myosin that makes up the backbone of the thick filament, four other proteins which are intimately bound to the thick filament, myosin binding protein-C, titin, myomesin, and obscurin play important structural and regulatory roles. Consistent with this, mutations in the respective genes have been associated with idiopathic and congenital forms of skeletal and cardiac myopathies. In this review, we aim to summarize our current knowledge on the molecular structure, subcellular localization, interacting partners, function, modulation via posttranslational modifications, and disease involvement of these five major proteins that comprise the thick filament of striated muscle cells. © 2018 American Physiological Society. Compr Physiol 8:631-709, 2018.
Collapse
Affiliation(s)
- Li Wang
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Janelle Geist
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Alyssa Grogan
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Li-Yen R Hu
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | | |
Collapse
|
21
|
Wang Y, Wang S, Lei M, Boyett M, Tsui H, Liu W, Wang X. The p21-activated kinase 1 (Pak1) signalling pathway in cardiac disease: from mechanistic study to therapeutic exploration. Br J Pharmacol 2017; 175:1362-1374. [PMID: 28574147 DOI: 10.1111/bph.13872] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/12/2017] [Accepted: 05/17/2017] [Indexed: 01/01/2023] Open
Abstract
p21-activated kinase 1 (Pak1) is a member of the highly conserved family of serine/threonine protein kinases regulated by Ras-related small G-proteins, Cdc42/Rac1. It has been previously demonstrated to be involved in cardiac protection. Based on recent studies, this review provides an overview of the role of Pak1 in cardiac diseases including disrupted Ca2+ homoeostasis-related cardiac arrhythmias, adrenergic stress- and pressure overload-induced hypertrophy, and ischaemia/reperfusion injury. These findings demonstrate the important role of Pak1 mediated through the phosphorylation and transcriptional modification of hypertrophy and/or arrhythmia-related genes. This review also discusses the anti-arrhythmic and anti-hypertrophic, protective function of Pak1 and the beneficial effects of fingolimod (an FDA-approved sphingolipid drug), a Pak1 activator, and its ability to prevent arrhythmias and cardiac hypertrophy. These findings also highlight the therapeutic potential of Pak1 signalling in the treatment and prevention of cardiac diseases. LINKED ARTICLES This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.
Collapse
Affiliation(s)
- Yanwen Wang
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Shunyao Wang
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Ming Lei
- Department of Pharmacology, The University of Oxford, Oxford, UK
| | - Mark Boyett
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Hoyee Tsui
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Wei Liu
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Xin Wang
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| |
Collapse
|
22
|
Lang SE, Stevenson TK, Schatz TM, Biesiadecki BJ, Westfall MV. Functional communication between PKC-targeted cardiac troponin I phosphorylation sites. Arch Biochem Biophys 2017; 627:1-9. [PMID: 28587770 DOI: 10.1016/j.abb.2017.05.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/16/2017] [Accepted: 05/31/2017] [Indexed: 11/18/2022]
Abstract
Increased protein kinase C (PKC) activity is associated with heart failure, and can target multiple cardiac troponin I (cTnI) residues in myocytes, including S23/24, S43/45 and T144. In earlier studies, cTnI-S43D and/or -S45D augmented S23/24 and T144 phosphorylation, which suggested there is communication between clusters. This communication is now explored by evaluating the impact of phospho-mimetic cTnI S43/45D combined with S23/24D (cTnIS4D) or T144D (cTnISDTD). Gene transfer of epitope-tagged cTnIS4D and cTnISDTD into adult cardiac myocytes progressively replaced endogenous cTnI. Partial replacement with cTnISDTD or cTnIS4D accelerated the time to peak (TTP) shortening and time to 50% re-lengthening (TTR50%) on day 2, but peak shortening was only diminished by cTnIS4D. Extensive cTnIS4D replacement continued to accelerate TTP, and decrease shortening amplitude, while TTR50% returned to baseline levels on day 4. In contrast, cTnISDTD modestly reduced shortening amplitude and continued to accelerate myocyte TTP and TTR50%. These results indicate cTnIS43/45 communicates with S23/24 and T144, with S23/24 exacerbating and T144 attenuating the S43/45D-dependent functional deficit. In addition, more severe functional alterations in cTnIS4D myocytes were accompanied by higher levels of secondary phosphorylation compared to cTnISDTD. These results suggest that secondary phosphorylation helps to maintain steady-state contractile function during chronic cTnI phosphorylation at PKC sites.
Collapse
Affiliation(s)
- Sarah E Lang
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, United States; Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Tamara K Stevenson
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, United States
| | - Tabea M Schatz
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, United States
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, United States
| | - Margaret V Westfall
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, United States; Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, United States.
| |
Collapse
|
23
|
Pseudophosphorylation of cardiac myosin regulatory light chain: a promising new tool for treatment of cardiomyopathy. Biophys Rev 2017; 9:57-64. [PMID: 28510043 DOI: 10.1007/s12551-017-0248-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 01/05/2017] [Indexed: 12/21/2022] Open
Abstract
Many genetic mutations in sarcomeric proteins, including the cardiac myosin regulatory light chain (RLC) encoded by the MYL2 gene, have been implicated in familial cardiomyopathies. Yet, the molecular mechanisms by which these mutant proteins regulate cardiac muscle mechanics in health and disease remain poorly understood. Evidence has been accumulating that RLC phosphorylation has an influential role in striated muscle contraction and, in addition to the conventional modulation via Ca2+ binding to troponin C, it can regulate cardiac muscle function. In this review, we focus on RLC mutations that have been reported to cause cardiomyopathy phenotypes via compromised RLC phosphorylation and elaborate on pseudo-phosphorylation rescue mechanisms. This new methodology has been discussed as an emerging exploratory tool to understand the role of phosphorylation as well as a genetic modality to prevent/rescue cardiomyopathy phenotypes. Finally, we summarize structural effects post-phosphorylation, a phenomenon that leads to an ordered shift in the myosin S1 and RLC conformational equilibrium between two distinct states.
Collapse
|
24
|
Vandenboom R. Modulation of Skeletal Muscle Contraction by Myosin Phosphorylation. Compr Physiol 2016; 7:171-212. [PMID: 28135003 DOI: 10.1002/cphy.c150044] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The striated muscle sarcomere is a highly organized and complex enzymatic and structural organelle. Evolutionary pressures have played a vital role in determining the structure-function relationship of each protein within the sarcomere. A key part of this multimeric assembly is the light chain-binding domain (LCBD) of the myosin II motor molecule. This elongated "beam" functions as a biological lever, amplifying small interdomain movements within the myosin head into piconewton forces and nanometer displacements against the thin filament during the cross-bridge cycle. The LCBD contains two subunits known as the essential and regulatory myosin light chains (ELC and RLC, respectively). Isoformic differences in these respective species provide molecular diversity and, in addition, sites for phosphorylation of serine residues, a highly conserved feature of striated muscle systems. Work on permeabilized skeletal fibers and thick filament systems shows that the skeletal myosin light chain kinase catalyzed phosphorylation of the RLC alters the "interacting head motif" of myosin motor heads on the thick filament surface, with myriad consequences for muscle biology. At rest, structure-function changes may upregulate actomyosin ATPase activity of phosphorylated cross-bridges. During activation, these same changes may increase the Ca2+ sensitivity of force development to enhance force, work, and power output, outcomes known as "potentiation." Thus, although other mechanisms may contribute, RLC phosphorylation may represent a form of thick filament activation that provides a "molecular memory" of contraction. The clinical significance of these RLC phosphorylation mediated alterations to contractile performance of various striated muscle systems are just beginning to be understood. © 2017 American Physiological Society. Compr Physiol 7:171-212, 2017.
Collapse
Affiliation(s)
- Rene Vandenboom
- Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, Ontario, Canada
| |
Collapse
|
25
|
Chang AN, Kamm KE, Stull JT. Role of myosin light chain phosphatase in cardiac physiology and pathophysiology. J Mol Cell Cardiol 2016; 101:35-43. [PMID: 27742556 DOI: 10.1016/j.yjmcc.2016.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/07/2016] [Accepted: 10/10/2016] [Indexed: 11/18/2022]
Abstract
Maintenance of contractile performance of the heart is achieved in part by the constitutive 40% phosphorylation of myosin regulatory light chain (RLC) in sarcomeres. The importance of this extent of RLC phosphorylation for optimal cardiac performance becomes apparent when various mouse models and resultant phenotypes are compared. The absence or attenuation of RLC phosphorylation results in poor performance leading to heart failure, whereas increased RLC phosphorylation is associated with cardiac protection from stresses. Although information is limited, RLC phosphorylation appears compromised in human heart failure which is consistent with data from mouse studies. The extent of cardiac RLC phosphorylation is determined by the balanced activities of cardiac myosin light chain kinases and phosphatases, the regulatory mechanisms of which are now emerging. This review thusly focuses on kinases that may participate in phosphorylating RLC to make the substrate for cardiac myosin light chain phosphatases, in addition to providing perspectives on the family of myosin light chain phosphatases and involved signaling mechanisms. Because biochemical and physiological information about cardiac myosin light chain phosphatase is sparse, such studies represent an emerging area of investigation in health and disease.
Collapse
Affiliation(s)
- Audrey N Chang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Kristine E Kamm
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - James T Stull
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| |
Collapse
|
26
|
Westfall MV. Contribution of Post-translational Phosphorylation to Sarcomere-Linked Cardiomyopathy Phenotypes. Front Physiol 2016; 7:407. [PMID: 27683560 PMCID: PMC5021686 DOI: 10.3389/fphys.2016.00407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 08/30/2016] [Indexed: 01/24/2023] Open
Abstract
Secondary shifts develop in post-translational phosphorylation of sarcomeric proteins in multiple animal models of inherited cardiomyopathy. These signaling alterations together with the primary mutation are predicted to contribute to the overall cardiac phenotype. As a result, identification and integration of post-translational myofilament signaling responses are identified as priorities for gaining insights into sarcomeric cardiomyopathies. However, significant questions remain about the nature and contribution of post-translational phosphorylation to structural remodeling and cardiac dysfunction in animal models and human patients. This perspective essay discusses specific goals for filling critical gaps about post-translational signaling in response to these inherited mutations, especially within sarcomeric proteins. The discussion focuses primarily on pre-clinical analysis of animal models and defines challenges and future directions in this field.
Collapse
|
27
|
Toepfer CN, West TG, Ferenczi MA. Revisiting Frank-Starling: regulatory light chain phosphorylation alters the rate of force redevelopment (ktr ) in a length-dependent fashion. J Physiol 2016; 594:5237-54. [PMID: 27291932 PMCID: PMC5023691 DOI: 10.1113/jp272441] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/01/2016] [Indexed: 11/24/2022] Open
Abstract
Key points Regulatory light chain (RLC) phosphorylation has been shown to alter the ability of muscle to produce force and power during shortening and to alter the rate of force redevelopment (ktr) at submaximal [Ca2+]. Increasing RLC phosphorylation ∼50% from the in vivo level in maximally [Ca2+]‐activated cardiac trabecula accelerates ktr. Decreasing RLC phosphorylation to ∼70% of the in vivo control level slows ktr and reduces force generation. ktr is dependent on sarcomere length in the physiological range 1.85–1.94 μm and RLC phosphorylation modulates this response. We demonstrate that Frank–Starling is evident at maximal [Ca2+] activation and therefore does not necessarily require length‐dependent change in [Ca2+]‐sensitivity of thin filament activation. The stretch response is modulated by changes in RLC phosphorylation, pinpointing RLC phosphorylation as a modulator of the Frank–Starling law in the heart. These data provide an explanation for slowed systolic function in the intact heart in response to RLC phosphorylation reduction.
Abstract Force and power in cardiac muscle have a known dependence on phosphorylation of the myosin‐associated regulatory light chain (RLC). We explore the effect of RLC phosphorylation on the ability of cardiac preparations to redevelop force (ktr) in maximally activating [Ca2+]. Activation was achieved by rapidly increasing the temperature (temperature‐jump of 0.5–20ºC) of permeabilized trabeculae over a physiological range of sarcomere lengths (1.85–1.94 μm). The trabeculae were subjected to shortening ramps over a range of velocities and the extent of RLC phosphorylation was varied. The latter was achieved using an RLC‐exchange technique, which avoids changes in the phosphorylation level of other proteins. The results show that increasing RLC phosphorylation by 50% accelerates ktr by ∼50%, irrespective of the sarcomere length, whereas decreasing phosphorylation by 30% slows ktr by ∼50%, relative to the ktr obtained for in vivo phosphorylation. Clearly, phosphorylation affects the magnitude of ktr following step shortening or ramp shortening. Using a two‐state model, we explore the effect of RLC phosphorylation on the kinetics of force development, which proposes that phosphorylation affects the kinetics of both attachment and detachment of cross‐bridges. In summary, RLC phosphorylation affects the rate and extent of force redevelopment. These findings were obtained in maximally activated muscle at saturating [Ca2+] and are not explained by changes in the Ca2+‐sensitivity of acto‐myosin interactions. The length‐dependence of the rate of force redevelopment, together with the modulation by the state of RLC phosphorylation, suggests that these effects play a role in the Frank–Starling law of the heart. Regulatory light chain (RLC) phosphorylation has been shown to alter the ability of muscle to produce force and power during shortening and to alter the rate of force redevelopment (ktr) at submaximal [Ca2+]. Increasing RLC phosphorylation ∼50% from the in vivo level in maximally [Ca2+]‐activated cardiac trabecula accelerates ktr. Decreasing RLC phosphorylation to ∼70% of the in vivo control level slows ktr and reduces force generation. ktr is dependent on sarcomere length in the physiological range 1.85–1.94 μm and RLC phosphorylation modulates this response. We demonstrate that Frank–Starling is evident at maximal [Ca2+] activation and therefore does not necessarily require length‐dependent change in [Ca2+]‐sensitivity of thin filament activation. The stretch response is modulated by changes in RLC phosphorylation, pinpointing RLC phosphorylation as a modulator of the Frank–Starling law in the heart. These data provide an explanation for slowed systolic function in the intact heart in response to RLC phosphorylation reduction.
Collapse
Affiliation(s)
- Christopher N Toepfer
- Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London, UK. .,Laboratory of Molecular Physiology, NHLBI, National Institutes of Health, Bethesda, MD, USA.
| | - Timothy G West
- Structure & Motion Laboratory, Royal Veterinary College London, North Mymms, UK
| | - Michael A Ferenczi
- Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London, UK.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| |
Collapse
|
28
|
Szczesna-Cordary D, de Tombe PP. Myosin light chain phosphorylation, novel targets to repair a broken heart? Cardiovasc Res 2016; 111:5-7. [PMID: 27190055 DOI: 10.1093/cvr/cvw098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Pieter P de Tombe
- Department of Cell and Molecular Physiology, Loyola University, Chicago, IL 60153, USA
| |
Collapse
|
29
|
Myosin light chain phosphorylation enhances contraction of heart muscle via structural changes in both thick and thin filaments. Proc Natl Acad Sci U S A 2016; 113:E3039-47. [PMID: 27162358 DOI: 10.1073/pnas.1602776113] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Contraction of heart muscle is triggered by calcium binding to the actin-containing thin filaments but modulated by structural changes in the myosin-containing thick filaments. We used phosphorylation of the myosin regulatory light chain (cRLC) by the cardiac isoform of its specific kinase to elucidate mechanisms of thick filament-mediated contractile regulation in demembranated trabeculae from the rat right ventricle. cRLC phosphorylation enhanced active force and its calcium sensitivity and altered thick filament structure as reported by bifunctional rhodamine probes on the cRLC: the myosin head domains became more perpendicular to the filament axis. The effects of cRLC phosphorylation on thick filament structure and its calcium sensitivity were mimicked by increasing sarcomere length or by deleting the N terminus of the cRLC. Changes in thick filament structure were highly cooperative with respect to either calcium concentration or extent of cRLC phosphorylation. Probes on unphosphorylated myosin heads reported similar structural changes when neighboring heads were phosphorylated, directly demonstrating signaling between myosin heads. Moreover probes on troponin showed that calcium sensitization by cRLC phosphorylation is mediated by the thin filament, revealing a signaling pathway between thick and thin filaments that is still present when active force is blocked by Blebbistatin. These results show that coordinated and cooperative structural changes in the thick and thin filaments are fundamental to the physiological regulation of contractility in the heart. This integrated dual-filament concept of contractile regulation may aid understanding of functional effects of mutations in the protein components of both filaments associated with heart disease.
Collapse
|
30
|
Yu H, Chakravorty S, Song W, Ferenczi MA. Phosphorylation of the regulatory light chain of myosin in striated muscle: methodological perspectives. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:779-805. [PMID: 27084718 PMCID: PMC5101276 DOI: 10.1007/s00249-016-1128-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/10/2016] [Accepted: 03/23/2016] [Indexed: 12/18/2022]
Abstract
Phosphorylation of the regulatory light chain (RLC) of myosin modulates cellular functions such as muscle contraction, mitosis, and cytokinesis. Phosphorylation defects are implicated in a number of diseases. Here we focus on striated muscle where changes in RLC phosphorylation relate to diseases such as hypertrophic cardiomyopathy and muscular dystrophy, or age-related changes. RLC phosphorylation in smooth muscle and non-muscle cells are covered briefly where relevant. There is much scientific interest in controlling the phosphorylation levels of RLC in vivo and in vitro in order to understand its physiological function in striated muscles. A summary of available and emerging in vivo and in vitro methods is presented. The physiological role of RLC phosphorylation and novel pathways are discussed to highlight the differences between muscle types and to gain insights into disease processes.
Collapse
Affiliation(s)
- Haiyang Yu
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, Level 3, 59 Nanyang Drive, Singapore, 636921, Singapore
| | - Samya Chakravorty
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, Level 3, 59 Nanyang Drive, Singapore, 636921, Singapore
| | - Weihua Song
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, Level 3, 59 Nanyang Drive, Singapore, 636921, Singapore
| | - Michael A Ferenczi
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, Level 3, 59 Nanyang Drive, Singapore, 636921, Singapore.
| |
Collapse
|
31
|
Pulcastro HC, Awinda PO, Breithaupt JJ, Tanner BCW. Effects of myosin light chain phosphorylation on length-dependent myosin kinetics in skinned rat myocardium. Arch Biochem Biophys 2016; 601:56-68. [PMID: 26763941 DOI: 10.1016/j.abb.2015.12.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/14/2015] [Accepted: 12/29/2015] [Indexed: 11/19/2022]
Abstract
Myosin force production is Ca(2+)-regulated by thin-filament proteins and sarcomere length, which together determine the number of cross-bridge interactions throughout a heartbeat. Ventricular myosin regulatory light chain-2 (RLC) binds to the neck of myosin and modulates contraction via its phosphorylation state. Previous studies reported regional variations in RLC phosphorylation across the left ventricle wall, suggesting that RLC phosphorylation could alter myosin behavior throughout the heart. We found that RLC phosphorylation varied across the left ventricle wall and that RLC phosphorylation was greater in the right vs. left ventricle. We also assessed functional consequences of RLC phosphorylation on Ca(2+)-regulated contractility as sarcomere length varied in skinned rat papillary muscle strips. Increases in RLC phosphorylation and sarcomere length both led to increased Ca(2+)-sensitivity of the force-pCa relationship, and both slowed cross-bridge detachment rate. RLC-phosphorylation slowed cross-bridge rates of MgADP release (∼30%) and MgATP binding (∼50%) at 1.9 μm sarcomere length, whereas RLC phosphorylation only slowed cross-bridge MgATP binding rate (∼55%) at 2.2 μm sarcomere length. These findings suggest that RLC phosphorylation influences cross-bridge kinetics differently as sarcomere length varies and support the idea that RLC phosphorylation could vary throughout the heart to meet different contractile demands between the left and right ventricles.
Collapse
Affiliation(s)
- Hannah C Pulcastro
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164-7620, USA
| | - Peter O Awinda
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164-7620, USA
| | - Jason J Breithaupt
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164-7620, USA
| | - Bertrand C W Tanner
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164-7620, USA.
| |
Collapse
|
32
|
Biesiadecki BJ, Ziolo MT. Should we treat heart failure with phosphatase inhibitors? Better to start at the end. J Mol Cell Cardiol 2015; 89:116-8. [PMID: 26497613 DOI: 10.1016/j.yjmcc.2015.10.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 10/16/2015] [Accepted: 10/19/2015] [Indexed: 01/21/2023]
Affiliation(s)
- Brandon J Biesiadecki
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
| | - Mark T Ziolo
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
33
|
Kampourakis T, Sun YB, Irving M. Orientation of the N- and C-terminal lobes of the myosin regulatory light chain in cardiac muscle. Biophys J 2015; 108:304-14. [PMID: 25606679 PMCID: PMC4302210 DOI: 10.1016/j.bpj.2014.11.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 11/07/2014] [Accepted: 11/10/2014] [Indexed: 02/02/2023] Open
Abstract
The orientations of the N- and C-terminal lobes of the cardiac isoform of the myosin regulatory light chain (cRLC) in the fully dephosphorylated state in ventricular trabeculae from rat heart were determined using polarized fluorescence from bifunctional sulforhodamine probes. cRLC mutants with one of eight pairs of surface-accessible cysteines were expressed, labeled with bifunctional sulforhodamine, and exchanged into demembranated trabeculae to replace some of the native cRLC. Polarized fluorescence data from the probes in each lobe were combined with RLC crystal structures to calculate the lobe orientation distribution with respect to the filament axis. The orientation distribution of the N-lobe had three distinct peaks (N1–N3) at similar angles in relaxation, isometric contraction, and rigor. The orientation distribution of the C-lobe had four peaks (C1–C4) in relaxation and isometric contraction, but only two of these (C2 and C4) remained in rigor. The N3 and C4 orientations are close to those of the corresponding RLC lobes in myosin head fragments bound to isolated actin filaments in the absence of ATP (in rigor), but also close to those of the pair of heads folded back against the filament surface in isolated thick filaments in the so-called J-motif conformation. The N1 and C1 orientations are close to those expected for actin-bound myosin heads with their light chain domains in a pre-powerstroke conformation. The N2 and C3 orientations have not been observed previously. The results show that the average change in orientation of the RLC region of the myosin heads on activation of cardiac muscle is small; the RLC regions of most heads remain in the same conformation as in relaxation. This suggests that the orientation of the dephosphorylated RLC region of myosin heads in cardiac muscle is primarily determined by an interaction with the thick filament surface.
Collapse
Affiliation(s)
- Thomas Kampourakis
- Randall Division of Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Yin-Biao Sun
- Randall Division of Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Malcolm Irving
- Randall Division of Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom.
| |
Collapse
|
34
|
Liu R, Correll RN, Davis J, Vagnozzi RJ, York AJ, Sargent MA, Nairn AC, Molkentin JD. Cardiac-specific deletion of protein phosphatase 1β promotes increased myofilament protein phosphorylation and contractile alterations. J Mol Cell Cardiol 2015; 87:204-13. [PMID: 26334248 PMCID: PMC4637224 DOI: 10.1016/j.yjmcc.2015.08.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 08/21/2015] [Accepted: 08/24/2015] [Indexed: 12/27/2022]
Abstract
There are 3 protein phosphatase 1 (PP1) catalytic isoforms (α, β and γ) encoded within the mammalian genome. These 3 gene products share ~90% amino acid homology within their catalytic domains but each has unique N- and C-termini that likely underlie distinctive subcellular localization or functionality. In this study, we assessed the effect associated with the loss of each PP1 isoform in the heart using a conditional Cre-loxP targeting approach in mice. Ppp1ca-loxP, Ppp1cb-loxP and Ppp1cc-loxP alleles were crossed with either an Nkx2.5-Cre knock-in containing allele for early embryonic deletion or a tamoxifen inducible α-myosin heavy chain (αMHC)-MerCreMer transgene for adult and cardiac-specific deletion. We determined that while deletion of Ppp1ca (PP1α) or Ppp1cc (PP1γ) had little effect on the whole heart, deletion of Ppp1cb (PP1β) resulted in concentric remodeling of the heart, interstitial fibrosis and contractile dysregulation, using either the embryonic or adult-specific Cre-expressing alleles. However, myocytes isolated from Ppp1cb deleted hearts surprisingly showed enhanced contractility. Mechanistically we found that deletion of any of the 3 PP1 gene-encoding isoforms had no effect on phosphorylation of phospholamban, nor were Ca(2+) handling dynamics altered in adult myocytes from Ppp1cb deleted hearts. However, the loss of Ppp1cb from the heart, but not Ppp1ca or Ppp1cc, resulted in elevated phosphorylation of myofilament proteins such as myosin light chain 2 and cardiac myosin binding protein C, consistent with an enriched localization profile of this isoform to the sarcomeres. These results suggest a unique functional role for the PP1β isoform in affecting cardiac contractile function.
Collapse
Affiliation(s)
- Ruijie Liu
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Howard Hughes Medical Institute, Cincinnati, OH 45229, USA
| | - Robert N Correll
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Howard Hughes Medical Institute, Cincinnati, OH 45229, USA
| | - Jennifer Davis
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Howard Hughes Medical Institute, Cincinnati, OH 45229, USA
| | - Ronald J Vagnozzi
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Howard Hughes Medical Institute, Cincinnati, OH 45229, USA
| | - Allen J York
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Howard Hughes Medical Institute, Cincinnati, OH 45229, USA
| | - Michelle A Sargent
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Howard Hughes Medical Institute, Cincinnati, OH 45229, USA
| | - Angus C Nairn
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06520 USA
| | - Jeffery D Molkentin
- Department of Pediatrics, University of Cincinnati, Cincinnati Children's Hospital Medical Center, Howard Hughes Medical Institute, Cincinnati, OH 45229, USA.
| |
Collapse
|
35
|
Huang W, Szczesna-Cordary D. Molecular mechanisms of cardiomyopathy phenotypes associated with myosin light chain mutations. J Muscle Res Cell Motil 2015; 36:433-45. [PMID: 26385864 DOI: 10.1007/s10974-015-9423-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/10/2015] [Indexed: 12/14/2022]
Abstract
We discuss here the potential mechanisms of action associated with hypertrophic (HCM) or dilated (DCM) cardiomyopathy causing mutations in the myosin regulatory (RLC) and essential (ELC) light chains. Specifically, we focus on four HCM mutations: RLC-A13T, RLC-K104E, ELC-A57G and ELC-M173V, and one DCM RLC-D94A mutation shown by population studies to cause different cardiomyopathy phenotypes in humans. Our studies indicate that RLC and ELC mutations lead to heart disease through different mechanisms with RLC mutations triggering alterations of the secondary structure of the RLC which further affect the structure and function of the lever arm domain and impose changes in the cross bridge cycling rates and myosin force generation ability. The ELC mutations exert their detrimental effects through changes in the interaction of the N-terminus of ELC with actin altering the cross talk between the thick and thin filaments and ultimately resulting in an altered force-pCa relationship. We also discuss the effect of mutations on myosin light chain phosphorylation. Exogenous myosin light chain phosphorylation and/or pseudo-phosphorylation were explored as potential rescue tools to treat hypertrophy-related cardiac phenotypes.
Collapse
Affiliation(s)
- Wenrui Huang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| |
Collapse
|
36
|
Constitutive phosphorylation of cardiac myosin regulatory light chain prevents development of hypertrophic cardiomyopathy in mice. Proc Natl Acad Sci U S A 2015; 112:E4138-46. [PMID: 26124132 DOI: 10.1073/pnas.1505819112] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Myosin light chain kinase (MLCK)-dependent phosphorylation of the regulatory light chain (RLC) of cardiac myosin is known to play a beneficial role in heart disease, but the idea of a phosphorylation-mediated reversal of a hypertrophic cardiomyopathy (HCM) phenotype is novel. Our previous studies on transgenic (Tg) HCM-RLC mice revealed that the D166V (Aspartate166 → Valine) mutation-induced changes in heart morphology and function coincided with largely reduced RLC phosphorylation in situ. We hypothesized that the introduction of a constitutively phosphorylated Serine15 (S15D) into the hearts of D166V mice would prevent the development of a deleterious HCM phenotype. In support of this notion, MLCK-induced phosphorylation of D166V-mutated hearts was found to rescue some of their abnormal contractile properties. Tg-S15D-D166V mice were generated with the human cardiac RLC-S15D-D166V construct substituted for mouse cardiac RLC and were subjected to functional, structural, and morphological assessments. The results were compared with Tg-WT and Tg-D166V mice expressing the human ventricular RLC-WT or its D166V mutant, respectively. Echocardiography and invasive hemodynamic studies demonstrated significant improvements of intact heart function in S15D-D166V mice compared with D166V, with the systolic and diastolic indices reaching those monitored in WT mice. A largely reduced maximal tension and abnormally high myofilament Ca(2+) sensitivity observed in D166V-mutated hearts were reversed in S15D-D166V mice. Low-angle X-ray diffraction study revealed that altered myofilament structures present in HCM-D166V mice were mitigated in S15D-D166V rescue mice. Our collective results suggest that expression of pseudophosphorylated RLC in the hearts of HCM mice is sufficient to prevent the development of the pathological HCM phenotype.
Collapse
|
37
|
Kampourakis T, Irving M. Phosphorylation of myosin regulatory light chain controls myosin head conformation in cardiac muscle. J Mol Cell Cardiol 2015; 85:199-206. [PMID: 26057075 PMCID: PMC4535163 DOI: 10.1016/j.yjmcc.2015.06.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 05/18/2015] [Accepted: 06/03/2015] [Indexed: 11/25/2022]
Abstract
The effect of phosphorylation on the conformation of the regulatory light chain (cRLC) region of myosin in ventricular trabeculae from rat heart was determined by polarized fluorescence from thiophosphorylated cRLCs labelled with bifunctional sulforhodamine (BSR). Less than 5% of cRLCs were endogenously phosphorylated in this preparation, and similarly low values of basal cRLC phosphorylation were measured in fresh intact ventricle from both rat and mouse hearts. BSR-labelled cRLCs were thiophosphorylated by a recombinant fragment of human cardiac myosin light chain kinase, which was shown to phosphorylate cRLCs specifically at serine 15 in a calcium- and calmodulin-dependent manner, both in vitro and in situ. The BSR-cRLCs were exchanged into demembranated trabeculae, and polarized fluorescence intensities measured for each BSR-cRLC in relaxation, active isometric contraction and rigor were combined with RLC crystal structures to calculate the orientation distribution of the C-lobe of the cRLC in each state. Only two of the four C-lobe orientation populations seen during relaxation and active isometric contraction in the unphosphorylated state were present after cRLC phosphorylation. Thus cRLC phosphorylation alters the equilibrium between defined conformations of the cRLC regions of the myosin heads, rather than simply disordering the heads as assumed previously. cRLC phosphorylation also changes the orientation of the cRLC C-lobe in rigor conditions, showing that the orientation of this part of the myosin head is determined by its interaction with the thick filament even when the head is strongly bound to actin. These results suggest that cRLC phosphorylation controls the contractility of the heart by modulating the interaction of the cRLC region of the myosin heads with the thick filament backbone. The orientation of the phosphorylated cRLC was measured by polarized fluorescence. Phosphorylated myosin heads are not disordered on the level of the cRLC region. cRLC phosphorylation induces a new conformational state of myosin. cRLC phosphorylation controls contractility at the myosin head–backbone interface.
Collapse
Affiliation(s)
- Thomas Kampourakis
- Randall Division of Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom.
| | - Malcolm Irving
- Randall Division of Cell and Molecular Biophysics and British Heart Foundation Centre of Research Excellence, King's College London, London SE1 1UL, United Kingdom
| |
Collapse
|
38
|
Huang W, Liang J, Yuan CC, Kazmierczak K, Zhou Z, Morales A, McBride KL, Fitzgerald-Butt SM, Hershberger RE, Szczesna-Cordary D. Novel familial dilated cardiomyopathy mutation in MYL2 affects the structure and function of myosin regulatory light chain. FEBS J 2015; 282:2379-93. [PMID: 25825243 DOI: 10.1111/febs.13286] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 02/27/2015] [Accepted: 03/26/2015] [Indexed: 01/16/2023]
Abstract
Dilated cardiomyopathy (DCM) is a disease of the myocardium characterized by left ventricular dilatation and diminished contractile function. Here we describe a novel DCM mutation in the myosin regulatory light chain (RLC), in which aspartic acid at position 94 is replaced by alanine (D94A). The mutation was identified by exome sequencing of three adult first-degree relatives who met formal criteria for idiopathic DCM. To obtain insight into the functional significance of this pathogenic MYL2 variant, we cloned and purified the human ventricular RLC wild-type (WT) and D94A mutant proteins, and performed in vitro experiments using RLC-mutant or WT-reconstituted porcine cardiac preparations. The mutation induced a reduction in the α-helical content of the RLC, and imposed intra-molecular rearrangements. The phosphorylation of RLC by Ca²⁺/calmodulin-activated myosin light chain kinase was not affected by D94A. The mutation was seen to impair binding of RLC to the myosin heavy chain, and its incorporation into RLC-depleted porcine myosin. The actin-activated ATPase activity of mutant-reconstituted porcine cardiac myosin was significantly higher compared with ATPase of wild-type. No changes in the myofibrillar ATPase-pCa relationship were observed in wild-type- or D94A-reconstituted preparations. Measurements of contractile force showed a slightly reduced maximal tension per cross-section of muscle, with no change in the calcium sensitivity of force in D94A-reconstituted skinned porcine papillary muscle strips compared with wild-type. Our data indicate that subtle structural rearrangements in the RLC molecule, followed by its impaired interaction with the myosin heavy chain, may trigger functional abnormalities contributing to the DCM phenotype.
Collapse
Affiliation(s)
- Wenrui Huang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jingsheng Liang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Chen-Ching Yuan
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Katarzyna Kazmierczak
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Zhiqun Zhou
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ana Morales
- Division of Human Genetics, Department of Internal Medicine, Wexner Medical Center, Ohio State University, Columbus, OH, USA
| | - Kim L McBride
- Department of Pediatrics Ohio State University, Center for Cardiovascular and Pulmonary Research, Nationwide Children's Hospital, Columbus, OH, USA
| | - Sara M Fitzgerald-Butt
- Department of Pediatrics Ohio State University, Center for Cardiovascular and Pulmonary Research, Nationwide Children's Hospital, Columbus, OH, USA
| | - Ray E Hershberger
- Division of Human Genetics, Department of Internal Medicine, Wexner Medical Center, Ohio State University, Columbus, OH, USA
| | - Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| |
Collapse
|
39
|
The R21C Mutation in Cardiac Troponin I Imposes Differences in Contractile Force Generation between the Left and Right Ventricles of Knock-In Mice. BIOMED RESEARCH INTERNATIONAL 2015; 2015:742536. [PMID: 25961037 PMCID: PMC4415466 DOI: 10.1155/2015/742536] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/16/2014] [Accepted: 12/19/2014] [Indexed: 01/20/2023]
Abstract
We investigated the effect of the hypertrophic cardiomyopathy-linked R21C (arginine to cysteine) mutation in human cardiac troponin I (cTnI) on the contractile properties and myofilament protein phosphorylation in papillary muscle preparations from left (LV) and right (RV) ventricles of homozygous R21C(+/+) knock-in mice. The maximal steady-state force was significantly reduced in skinned papillary muscle strips from the LV compared to RV, with the latter displaying the level of force observed in LV or RV from wild-type (WT) mice. There were no differences in the Ca(2+) sensitivity between the RV and LV of R21C(+/+) mice; however, the Ca(2+) sensitivity of force was higher in RV-R21C(+/+) compared with RV-WT and lower in LV- R21C(+/+) compared with LV-WT. We also observed partial loss of Ca(2+) regulation at low [Ca(2+)]. In addition, R21C(+/+)-KI hearts showed no Ser23/24-cTnI phosphorylation compared to LV or RV of WT mice. However, phosphorylation of the myosin regulatory light chain (RLC) was significantly higher in the RV versus LV of R21C(+/+) mice and versus LV and RV of WT mice. The difference in RLC phosphorylation between the ventricles of R21C(+/+) mice likely contributes to observed differences in contractile force and the lower tension monitored in the LV of HCM mice.
Collapse
|
40
|
Rosas PC, Liu Y, Abdalla MI, Thomas CM, Kidwell DT, Dusio GF, Mukhopadhyay D, Kumar R, Baker KM, Mitchell BM, Powers PA, Fitzsimons DP, Patel BG, Warren CM, Solaro RJ, Moss RL, Tong CW. Phosphorylation of cardiac Myosin-binding protein-C is a critical mediator of diastolic function. Circ Heart Fail 2015; 8:582-94. [PMID: 25740839 DOI: 10.1161/circheartfailure.114.001550] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 02/24/2015] [Indexed: 01/06/2023]
Abstract
BACKGROUND Heart failure (HF) with preserved ejection fraction (HFpEF) accounts for ≈50% of all cases of HF and currently has no effective treatment. Diastolic dysfunction underlies HFpEF; therefore, elucidation of the mechanisms that mediate relaxation can provide new potential targets for treatment. Cardiac myosin-binding protein-C (cMyBP-C) is a thick filament protein that modulates cross-bridge cycling rates via alterations in its phosphorylation status. Thus, we hypothesize that phosphorylated cMyBP-C accelerates the rate of cross-bridge detachment, thereby enhancing relaxation to mediate diastolic function. METHODS AND RESULTS We compared mouse models expressing phosphorylation-deficient cMyBP-C(S273A/S282A/S302A)-cMyBP-C(t3SA), phosphomimetic cMyBP-C(S273D/S282D/S302D)-cMyBP-C(t3SD), and wild-type-control cMyBP-C(tWT) to elucidate the functional effects of cMyBP-C phosphorylation. Decreased voluntary running distances, increased lung/body weight ratios, and increased brain natriuretic peptide levels in cMyBP-C(t3SA) mice demonstrate that phosphorylation deficiency is associated with signs of HF. Echocardiography (ejection fraction and myocardial relaxation velocity) and pressure/volume measurements (-dP/dtmin, pressure decay time constant τ-Glantz, and passive filling stiffness) show that cMyBP-C phosphorylation enhances myocardial relaxation in cMyBP-C(t3SD) mice, whereas deficient cMyBP-C phosphorylation causes diastolic dysfunction with HFpEF in cMyBP-C(t3SA) mice. Simultaneous force and [Ca(2+)]i measurements on intact papillary muscles show that enhancement of relaxation in cMyBP-C(t3SD) mice and impairment of relaxation in cMyBP-C(t3SA) mice are not because of altered [Ca(2+)]i handling, implicating that altered cross-bridge detachment rates mediate these changes in relaxation rates. CONCLUSIONS cMyBP-C phosphorylation enhances relaxation, whereas deficient phosphorylation causes diastolic dysfunction and phenotypes resembling HFpEF. Thus, cMyBP-C is a potential target for treatment of HFpEF.
Collapse
Affiliation(s)
- Paola C Rosas
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Yang Liu
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Mohamed I Abdalla
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Candice M Thomas
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - David T Kidwell
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Giuseppina F Dusio
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Dhriti Mukhopadhyay
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Rajesh Kumar
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Kenneth M Baker
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Brett M Mitchell
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Patricia A Powers
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Daniel P Fitzsimons
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Bindiya G Patel
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Chad M Warren
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - R John Solaro
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Richard L Moss
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.)
| | - Carl W Tong
- From the Department of Medical Physiology (P.C.R., Y.L., M.I.A., B.M.M., C.W.T.) and Division of Molecular Cardiology, Department of Medicine (C.M.T., R.K., K.M.B.), Texas A&M University Health Science Center, College of Medicine, Temple City; Internal Medicine/Division of Cardiology (D.T.K., C.W.T.) and Department of Surgery (G.F.D., D.M.), Baylor Scott & White Health-Central Texas, Temple City; Department of Cell and Regenerative Biology and Biotechnology Center, University of Wisconsin School of Medicine and Public Health, Madison (P.A.P., D.P.F., R.L.M.); and Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago (B.G.P., C.M.W., R.J.S.).
| |
Collapse
|
41
|
Chang AN, Battiprolu PK, Cowley PM, Chen G, Gerard RD, Pinto JR, Hill JA, Baker AJ, Kamm KE, Stull JT. Constitutive phosphorylation of cardiac myosin regulatory light chain in vivo. J Biol Chem 2015; 290:10703-16. [PMID: 25733667 DOI: 10.1074/jbc.m115.642165] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Indexed: 01/03/2023] Open
Abstract
In beating hearts, phosphorylation of myosin regulatory light chain (RLC) at a single site to 0.45 mol of phosphate/mol by cardiac myosin light chain kinase (cMLCK) increases Ca(2+) sensitivity of myofilament contraction necessary for normal cardiac performance. Reduction of RLC phosphorylation in conditional cMLCK knock-out mice caused cardiac dilation and loss of cardiac performance by 1 week, as shown by increased left ventricular internal diameter at end-diastole and decreased fractional shortening. Decreased RLC phosphorylation by conventional or conditional cMLCK gene ablation did not affect troponin-I or myosin-binding protein-C phosphorylation in vivo. The extent of RLC phosphorylation was not changed by prolonged infusion of dobutamine or treatment with a β-adrenergic antagonist, suggesting that RLC is constitutively phosphorylated to maintain cardiac performance. Biochemical studies with myofilaments showed that RLC phosphorylation up to 90% was a random process. RLC is slowly dephosphorylated in both noncontracting hearts and isolated cardiac myocytes from adult mice. Electrically paced ventricular trabeculae restored RLC phosphorylation, which was increased to 0.91 mol of phosphate/mol of RLC with inhibition of myosin light chain phosphatase (MLCP). The two RLCs in each myosin appear to be readily available for phosphorylation by a soluble cMLCK, but MLCP activity limits the amount of constitutive RLC phosphorylation. MLCP with its regulatory subunit MYPT2 bound tightly to myofilaments was constitutively phosphorylated in beating hearts at a site that inhibits MLCP activity. Thus, the constitutive RLC phosphorylation is limited physiologically by low cMLCK activity in balance with low MLCP activity.
Collapse
Affiliation(s)
| | | | - Patrick M Cowley
- the Veterans Affairs Medical Center, San Francisco, California 94143, the University of California, San Francisco, California 94143, and
| | | | - Robert D Gerard
- Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Jose R Pinto
- the Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida 32306
| | - Joseph A Hill
- Internal Medicine (Cardiology), and Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Anthony J Baker
- the Veterans Affairs Medical Center, San Francisco, California 94143, the University of California, San Francisco, California 94143, and
| | | | | |
Collapse
|
42
|
Tøndel K, Land S, Niederer SA, Smith NP. Quantifying inter-species differences in contractile function through biophysical modelling. J Physiol 2015; 593:1083-111. [PMID: 25480801 DOI: 10.1113/jphysiol.2014.279232] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/28/2014] [Indexed: 11/08/2022] Open
Abstract
Animal models and measurements are frequently used to guide and evaluate clinical interventions. In this context, knowledge of inter-species differences in physiology is crucial for understanding the limitations and relevance of animal experimental assays for informing clinical applications. Extensive effort has been put into studying the structure and function of cardiac contractile proteins and how differences in these translate into the functional properties of muscles. However, integrating this knowledge into a quantitative description, formalising and highlighting inter-species differences both in the kinetics and in the regulation of physiological mechanisms, remains challenging. In this study we propose and apply a novel approach for the quantification of inter-species differences between mouse, rat and human. Assuming conservation of the fundamental physiological mechanisms underpinning contraction, biophysically based computational models are fitted to simulate experimentally recorded phenotypes from multiple species. The phenotypic differences between species are then succinctly quantified as differences in the biophysical model parameter values. This provides the potential of quantitatively establishing the human relevance of both animal-based experimental and computational models for application in a clinical context. Our results indicate that the parameters related to the sensitivity and cooperativity of calcium binding to troponin C and the activation and relaxation rates of tropomyosin/crossbridge binding kinetics differ most significantly between mouse, rat and human, while for example the reference tension, as expected, shows only minor differences between the species. Hence, while confirming expected inter-species differences in calcium sensitivity due to large differences in the observed calcium transients, our results also indicate more unexpected differences in the cooperativity mechanism. Specifically, the decrease in the unbinding rate of calcium to troponin C with increasing active tension was much lower for mouse than for rat and human. Our results also predicted crossbridge binding to be slowest in human and fastest in mouse.
Collapse
Affiliation(s)
- Kristin Tøndel
- Department of Biomedical Engineering, King's College London, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, UK; Simula Research Laboratory, Martin Linges v. 17/25, Rolfsbukta 4B, Fornebu, 1364, Norway
| | | | | | | |
Collapse
|
43
|
The role of super-relaxed myosin in skeletal and cardiac muscle. Biophys Rev 2014; 7:5-14. [PMID: 28509977 DOI: 10.1007/s12551-014-0151-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 11/16/2014] [Indexed: 01/10/2023] Open
Abstract
The super-relaxed (SRX) state of myosin was only recently reported in striated muscle. It is characterised by a sub-population of myosin heads with a highly inhibited rate of ATP turnover. Myosin heads in the SRX state are bound to each other along the thick filament core producing a highly ordered arrangement. Upon activation, these heads project into the interfilament space where they can bind to the actin filaments. Thus far, the population and lifetimes of myosin heads in the SRX state have been characterised in rabbit cardiac, and fast and slow skeletal muscle, as well as in the skeletal muscle of the tarantula. These studies suggest that the role of SRX in cardiac and skeletal muscle regulation is tailored to their specific functions. In skeletal muscle, the SRX modulates the resting metabolic rate. Cardiac SRX represents a "reserve" of inactive myosin heads that may protect the heart during times of stress, e.g. hypoxia and ischaemia. These heads may also be called up when there is a sustained demand for increased power. The SRX in cardiac muscle provides a potential target for novel therapies.
Collapse
|
44
|
Jiang Y, Wang Y, Wang T, Hawke DH, Zheng Y, Li X, Zhou Q, Majumder S, Bi E, Liu DX, Huang S, Lu Z. PKM2 phosphorylates MLC2 and regulates cytokinesis of tumour cells. Nat Commun 2014; 5:5566. [PMID: 25412762 PMCID: PMC4259466 DOI: 10.1038/ncomms6566] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 10/14/2014] [Indexed: 02/07/2023] Open
Abstract
Pyruvate kinase M2 (PKM2) is expressed at high levels during embryonic development and tumour progression and is important for cell growth. However, it is not known whether it directly controls cell division. Here, we found that Aurora B phosphorylates PKM2, but not PKM1, at T45; this phosphorylation is required for PKM2's localization and interaction with myosin light chain 2 (MLC2) in the contractile ring region of mitotic cells during cytokinesis. PKM2 phosphorylates MLC2 at Y118, which primes the binding of ROCK2 to MLC2 and subsequent ROCK2-dependent MLC2 S15 phosphorylation. PKM2-regulated MLC2 phosphorylation, which is greatly enhanced by EGF stimulation or EGFRvIII, K-Ras G12V and B-Raf V600E mutant expression, plays a pivotal role in cytokinesis, cell proliferation and brain tumour development. These findings underscore the instrumental function of PKM2 in oncogenic EGFR-, K-Ras- and B-Raf-regulated cytokinesis and tumorigenesis.
Collapse
Affiliation(s)
- Yuhui Jiang
- Brain Tumor Center and Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yugang Wang
- Brain Tumor Center and Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ting Wang
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David H. Hawke
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yanhua Zheng
- Brain Tumor Center and Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xinjian Li
- Brain Tumor Center and Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Qin Zhou
- The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Sadhan Majumder
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David X. Liu
- Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, WA 99202, USA
| | - Suyun Huang
- Departments of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Zhimin Lu
- Brain Tumor Center and Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Cancer Biology Program, The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA
| |
Collapse
|
45
|
Sheikh F, Lyon RC, Chen J. Getting the skinny on thick filament regulation in cardiac muscle biology and disease. Trends Cardiovasc Med 2014; 24:133-41. [PMID: 23968570 PMCID: PMC3877703 DOI: 10.1016/j.tcm.2013.07.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/03/2013] [Accepted: 07/05/2013] [Indexed: 12/21/2022]
Abstract
Thin (actin) filament accessory proteins are thought to be the regulatory force for muscle contraction in cardiac muscle; however, compelling new evidence suggests that thick (myosin) filament regulatory proteins are emerging as having independent and important roles in regulating cardiac muscle contraction. Key to these new findings is a growing body of evidence that point to an influential and, more recently, direct role for ventricular myosin light chain-2 (MLC2v) phosphorylation in regulating cardiac muscle contraction, function, and disease. This includes the discovery and characterization of a cardiac-specific myosin light chain kinase capable of phosphorylating MLC2v as well as a myosin phosphatase that dephosphorylates MLC2v in the heart, which provides added mechanistic insights on MLC2v regulation within cardiac muscle. Here, we review evidence for an emerging and critical role for MLC2v phosphorylation in regulating cardiac myosin cycling kinetics, function, and disease, based on recent studies performed in genetic mouse models and humans. We further provide new perspectives on future avenues for targeting these pathways as therapies in alleviating cardiac disease.
Collapse
Affiliation(s)
- Farah Sheikh
- Department of Medicine (Cardiology Division), University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| | - Robert C Lyon
- Department of Medicine (Cardiology Division), University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Ju Chen
- Department of Medicine (Cardiology Division), University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| |
Collapse
|
46
|
Monasky MM, Taglieri DM, Henze M, Warren CM, Utter MS, Soergel DG, Violin JD, Solaro RJ. The β-arrestin-biased ligand TRV120023 inhibits angiotensin II-induced cardiac hypertrophy while preserving enhanced myofilament response to calcium. Am J Physiol Heart Circ Physiol 2013; 305:H856-66. [PMID: 23873795 DOI: 10.1152/ajpheart.00327.2013] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In the present study, we compared the cardioprotective effects of TRV120023, a novel angiotensin II (ANG II) type 1 receptor (AT1R) ligand, which blocks G protein coupling but stimulates β-arrestin signaling, against treatment with losartan, a conventional AT1R blocker in the treatment of cardiac hypertrophy and regulation of myofilament activity and phosphorylation. Rats were subjected to 3 wk of treatment with saline, ANG II, ANG II + losartan, ANG II + TRV120023, or TRV120023 alone. ANG II induced increased left ventricular mass compared with rats that received ANG II + losartan or ANG II + TRV120023. Compared with saline controls, ANG II induced a significant increase in pCa50 and maximum Ca(2+)-activated myofilament tension but reduced the Hill coefficient (nH). TRV120023 increased maximum tension and pCa50, although to lesser extent than ANG II. In contrast to ANG II, TRV120023 increased nH. Losartan blocked the effects of ANG II on pCa50 and nH and reduced maximum tension below that of saline controls. ANG II + TRV120023 showed responses similar to those of TRV120023 alone; compared with ANG II + losartan, ANG II + TRV120023 preserved maximum tension and increased both pCa50 and cooperativity. Tropomyosin phosphorylation was lower in myofilaments from saline-treated hearts compared with the other groups. Phosphorylation of cardiac troponin I was significantly reduced in ANG II + TRV120023 and TRV120023 groups versus saline controls, and myosin-binding protein C phosphorylation at Ser(282) was unaffected by ANG II or losartan but significantly reduced with TRV120023 treatment compared with all other groups. Our data indicate that TRV120023-related promotion of β-arrestin signaling and enhanced contractility involves a mechanism promoting the myofilament response to Ca(2+) via altered protein phosphorylation. Selective activation of β-arrestin-dependent pathways may provide advantages over conventional AT1R blockers.
Collapse
Affiliation(s)
- Michelle M Monasky
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois, Chicago, Illinois; and
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Monasky MM, Taglieri DM, Jacobson AK, Haizlip KM, Solaro RJ, Janssen PM. Post-translational modifications of myofilament proteins involved in length-dependent prolongation of relaxation in rabbit right ventricular myocardium. Arch Biochem Biophys 2013; 535:22-9. [PMID: 23085150 PMCID: PMC3640662 DOI: 10.1016/j.abb.2012.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/02/2012] [Accepted: 10/10/2012] [Indexed: 12/27/2022]
Abstract
The phosphorylation state of several cardiac myofilament proteins changes with the level of stretch in intact, twitch-contracting cardiac muscles. It remains unclear which kinases are involved in the length-dependent phosphorylation of these proteins. We set out to investigate which kinases are involved after a step-wise change in cardiac muscle length. We hypothesize that myofilament protein phosphorylation by PKCβII and PKA alters contractile kinetics during length-dependent activation. Right ventricular intact trabeculae were isolated from New Zealand White rabbit hearts and stimulated to contract at 1Hz. Twitch force recordings where taken at taut and optimal muscle lengths before and after administration of kinase inhibitors at 37°C. PKCβII inhibition significantly decreased time from stimulation to peak force (TTP), time from peak force to 50% relaxation (RT50), and 90% relaxation (RT90) at optimal muscle length. This led to a loss in the length-dependent increase of RT50 and RT90 in the presence of the PKCβII inhibitor, whereas the length-dependent increase in RT50 and RT90 was seen in the controls. PKA inhibition using H-89 significantly decreased TTP at both taut and optimal muscle lengths. Detection of Ser/Thr phosphorylation with ProQ-diamond staining indicates a role for PKCβII in the phosphorylation of tropomyosin and myosin light chain-2 (MLC2) and PKA for tropomyosin, troponin-I, MLC2, myosin binding protein-C, troponin-T (TnT) 3 and TnT4. Our data provide evidence for two signaling kinases acting upon myofilament proteins during length-dependent activation, and provide further insight for length-dependent myofilament function.
Collapse
Affiliation(s)
- Michelle M. Monasky
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Avenue (M/C 901), Chicago, IL 60612-7342, USA
| | - Domenico M. Taglieri
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Avenue (M/C 901), Chicago, IL 60612-7342, USA
| | - Alice K. Jacobson
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Kaylan M. Haizlip
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - R. John Solaro
- Department of Physiology and Biophysics and Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Avenue (M/C 901), Chicago, IL 60612-7342, USA
| | - Paul M.L. Janssen
- Department of Physiology and Cell Biology, College of Medicine and D. Davis Heart Lung Institute, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| |
Collapse
|
48
|
Schulz EM, Wieczorek DF. Tropomyosin de-phosphorylation in the heart: What are the consequences? J Muscle Res Cell Motil 2013; 34:239-46. [DOI: 10.1007/s10974-013-9348-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/24/2013] [Indexed: 11/30/2022]
|
49
|
The effects of neuregulin on cardiac Myosin light chain kinase gene-ablated hearts. PLoS One 2013; 8:e66720. [PMID: 23776695 PMCID: PMC3679076 DOI: 10.1371/journal.pone.0066720] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/09/2013] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Activation of ErbB2/4 receptor tyrosine kinases in cardiomyocytes by neuregulin treatment is associated with improvement in cardiac function, supporting its use in human patients with heart failure despite the lack of a specific mechanism. Neuregulin infusion in rodents increases cardiac myosin light chain kinase (cMLCK) expression and cardiac myosin regulatory light chain (RLC) phosphorylation which may improve actin-myosin interactions for contraction. We generated a cMLCK knockout mouse to test the hypothesis that cMLCK is necessary for neuregulin-induced improvement in cardiac function by increasing RLC phosphorylation. PRINCIPAL FINDINGS The cMLCK knockout mice have attenuated RLC phosphorylation and decreased cardiac performance measured as fractional shortening. Neuregulin infusion for seven days in wildtype mice increased cardiac cMLCK protein expression and RLC phosphorylation while increasing Akt phosphorylation and decreasing phospholamban phosphorylation. There was no change in fractional shortening. In contrast, neuregulin infusion in cMLCK knockout animals increased cardiac performance in the absence of cMLCK without increasing RLC phosphorylation. In addition, CaMKII signaling appeared to be enhanced in neuregulin-treated knockout mice. CONCLUSIONS Thus, Neuregulin may improve cardiac performance in the failing heart without increasing cMLCK and RLC phosphorylation by activating other signaling pathways.
Collapse
|
50
|
Toepfer C, Caorsi V, Kampourakis T, Sikkel MB, West TG, Leung MC, Al-Saud SA, MacLeod KT, Lyon AR, Marston SB, Sellers JR, Ferenczi MA. Myosin regulatory light chain (RLC) phosphorylation change as a modulator of cardiac muscle contraction in disease. J Biol Chem 2013; 288:13446-54. [PMID: 23530050 PMCID: PMC3650382 DOI: 10.1074/jbc.m113.455444] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 03/21/2013] [Indexed: 01/26/2023] Open
Abstract
Understanding how cardiac myosin regulatory light chain (RLC) phosphorylation alters cardiac muscle mechanics is important because it is often altered in cardiac disease. The effect this protein phosphorylation has on muscle mechanics during a physiological range of shortening velocities, during which the heart generates power and performs work, has not been addressed. We have expressed and phosphorylated recombinant Rattus norvegicus left ventricular RLC. In vitro we have phosphorylated these recombinant species with cardiac myosin light chain kinase and zipper-interacting protein kinase. We compare rat permeabilized cardiac trabeculae, which have undergone exchange with differently phosphorylated RLC species. We were able to enrich trabecular RLC phosphorylation by 40% compared with controls and, in a separate series, lower RLC phosphorylation to 60% of control values. Compared with the trabeculae with a low level of RLC phosphorylation, RLC phosphorylation enrichment increased isometric force by more than 3-fold and peak power output by more than 7-fold and approximately doubled both maximum shortening speed and the shortening velocity that generated peak power. We augmented these measurements by observing increased RLC phosphorylation of human and rat HF samples from endocardial left ventricular homogenate. These results demonstrate the importance of increased RLC phosphorylation in the up-regulation of myocardial performance and suggest that reduced RLC phosphorylation is a key aspect of impaired contractile function in the diseased myocardium.
Collapse
Affiliation(s)
- Christopher Toepfer
- From the Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London SW7 2AZ, United Kingdom
- the Laboratory of Molecular Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Valentina Caorsi
- From the Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London SW7 2AZ, United Kingdom
| | - Thomas Kampourakis
- the Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, United Kingdom
| | - Markus B. Sikkel
- the National Heart and Lung Institute, 4th Floor, Imperial Center for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, United Kingdom
| | - Timothy G. West
- the Structure and Motion Laboratory, Royal Veterinary College London, North Mymms AL9 7TA, United Kingdom
| | - Man-Ching Leung
- the National Heart and Lung Institute, 4th Floor, Imperial Center for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, United Kingdom
| | - Sara A. Al-Saud
- From the Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London SW7 2AZ, United Kingdom
| | - Kenneth T. MacLeod
- the National Heart and Lung Institute, 4th Floor, Imperial Center for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, United Kingdom
| | - Alexander R. Lyon
- the National Heart and Lung Institute, 4th Floor, Imperial Center for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, United Kingdom
- the Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London SW3 6MP, United Kingdom
| | - Steven B. Marston
- the National Heart and Lung Institute, 4th Floor, Imperial Center for Translational and Experimental Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, United Kingdom
| | - James R. Sellers
- the Laboratory of Molecular Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Michael A. Ferenczi
- From the Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London SW7 2AZ, United Kingdom
- the Lee Kong Chian School of Medicine, Nanyang Technological University, 637553 Singapore
| |
Collapse
|