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Blaustein MP, Hamlyn JM. Sensational site: the sodium pump ouabain-binding site and its ligands. Am J Physiol Cell Physiol 2024; 326:C1120-C1177. [PMID: 38223926 PMCID: PMC11193536 DOI: 10.1152/ajpcell.00273.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/22/2023] [Accepted: 01/10/2024] [Indexed: 01/16/2024]
Abstract
Cardiotonic steroids (CTS), used by certain insects, toads, and rats for protection from predators, became, thanks to Withering's trailblazing 1785 monograph, the mainstay of heart failure (HF) therapy. In the 1950s and 1960s, we learned that the CTS receptor was part of the sodium pump (NKA) and that the Na+/Ca2+ exchanger was critical for the acute cardiotonic effect of digoxin- and ouabain-related CTS. This "settled" view was upended by seven revolutionary observations. First, subnanomolar ouabain sometimes stimulates NKA while higher concentrations are invariably inhibitory. Second, endogenous ouabain (EO) was discovered in the human circulation. Third, in the DIG clinical trial, digoxin only marginally improved outcomes in patients with HF. Fourth, cloning of NKA in 1985 revealed multiple NKA α and β subunit isoforms that, in the rodent, differ in their sensitivities to CTS. Fifth, the NKA is a cation pump and a hormone receptor/signal transducer. EO binding to NKA activates, in a ligand- and cell-specific manner, several protein kinase and Ca2+-dependent signaling cascades that have widespread physiological effects and can contribute to hypertension and HF pathogenesis. Sixth, all CTS are not equivalent, e.g., ouabain induces hypertension in rodents while digoxin is antihypertensinogenic ("biased signaling"). Seventh, most common rodent hypertension models require a highly ouabain-sensitive α2 NKA and the elevated blood pressure is alleviated by EO immunoneutralization. These numerous phenomena are enabled by NKA's intricate structure. We have just begun to understand the endocrine role of the endogenous ligands and the broad impact of the ouabain-binding site on physiology and pathophysiology.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States
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Asunción-Alvarez D, Palacios J, Ybañez-Julca RO, Rodriguez-Silva CN, Nwokocha C, Cifuentes F, Greensmith DJ. Calcium signaling in endothelial and vascular smooth muscle cells: sex differences and the influence of estrogens and androgens. Am J Physiol Heart Circ Physiol 2024; 326:H950-H970. [PMID: 38334967 DOI: 10.1152/ajpheart.00600.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/05/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
Calcium signaling in vascular endothelial cells (ECs) and smooth muscle cells (VSMCs) is essential for the regulation of vascular tone. However, the changes to intracellular Ca2+ concentrations are often influenced by sex differences. Furthermore, a large body of evidence shows that sex hormone imbalance leads to dysregulation of Ca2+ signaling and this is a key factor in the pathogenesis of cardiovascular diseases. In this review, the effects of estrogens and androgens on vascular calcium-handling proteins are discussed, with emphasis on the associated genomic or nongenomic molecular mechanisms. The experimental models from which data were collected were also considered. The review highlights 1) in female ECs, transient receptor potential vanilloid 4 (TRPV4) and mitochondrial Ca2+ uniporter (MCU) enhance Ca2+-dependent nitric oxide (NO) generation. In males, only transient receptor potential canonical 3 (TRPC3) plays a fundamental role in this effect. 2) Female VSMCs have lower cytosolic Ca2+ levels than males due to differences in the activity and expression of stromal interaction molecule 1 (STIM1), calcium release-activated calcium modulator 1 (Orai1), calcium voltage-gated channel subunit-α1C (CaV1.2), Na+-K+-2Cl- symporter (NKCC1), and the Na+/K+-ATPase. 3) When compared with androgens, the influence of estrogens on Ca2+ homeostasis, vascular tone, and incidence of vascular disease is better documented. 4) Many studies use supraphysiological concentrations of sex hormones, which may limit the physiological relevance of outcomes. 5) Sex-dependent differences in Ca2+ signaling mean both sexes ought to be included in experimental design.
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Affiliation(s)
- Daniel Asunción-Alvarez
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Javier Palacios
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Roberto O Ybañez-Julca
- Departamento de Farmacología, Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo, Perú
| | - Cristhian N Rodriguez-Silva
- Departamento de Farmacología, Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo, Perú
| | - Chukwuemeka Nwokocha
- Department of Basic Medical Sciences Physiology Section, Faculty of Medical Sciences, The University of the West Indies, Kingston, Jamaica
| | - Fredi Cifuentes
- Laboratorio de Fisiología Experimental (EphyL), Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, Chile
| | - David J Greensmith
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom
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Chen HX, Wang XC, Hou HT, Wang J, Yang Q, Chen YL, Chen HZ, He GW. Lysine crotonylation of SERCA2a correlates to cardiac dysfunction and arrhythmia in Sirt1 cardiac-specific knockout mice. Int J Biol Macromol 2023; 242:125151. [PMID: 37270127 DOI: 10.1016/j.ijbiomac.2023.125151] [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: 12/14/2022] [Revised: 03/08/2023] [Accepted: 05/27/2023] [Indexed: 06/05/2023]
Abstract
Protein post-translational modifications (PTMs) are important regulators of protein functions and produce proteome complexity. SIRT1 has NAD+-dependent deacylation of acyl-lysine residues. The present study aimed to explore the correlation between lysine crotonylation (Kcr) on cardiac function and rhythm in Sirt1 cardiac-specific knockout (ScKO) mice and related mechanism. Quantitative proteomics and bioinformatics analysis of Kcr were performed in the heart tissue of ScKO mice established with a tamoxifen-inducible Cre-loxP system. The expression and enzyme activity of crotonylated protein were assessed by western blot, co-immunoprecipitation, and cell biology experiment. Echocardiography and electrophysiology were performed to investigate the influence of decrotonylation on cardiac function and rhythm in ScKO mice. The Kcr of SERCA2a was significantly increased on Lys120 (1.973 folds). The activity of SERCA2a decreased due to lower binding energy of crotonylated SERCA2a and ATP. Changes in expression of PPAR-related proteins suggest abnormal energy metabolism in the heart. ScKO mice had cardiac hypertrophy, impaired cardiac function, and abnormal ultrastructure and electrophysiological activities. We conclude that knockout of SIRT1 alters the ultrastructure of cardiac myocytes, induces cardiac hypertrophy and dysfunction, causes arrhythmia, and changes energy metabolism by regulating Kcr of SERCA2a. These findings provide new insight into the role of PTMs in heart diseases.
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Affiliation(s)
- Huan-Xin Chen
- The Institute of Cardiovascular Diseases & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Tianjin University & Chinese Academy of Medical Sciences, Tianjin 300457, China
| | - Xiang-Chong Wang
- The Institute of Cardiovascular Diseases & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Tianjin University & Chinese Academy of Medical Sciences, Tianjin 300457, China
| | - Hai-Tao Hou
- The Institute of Cardiovascular Diseases & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Tianjin University & Chinese Academy of Medical Sciences, Tianjin 300457, China
| | - Jun Wang
- The Institute of Cardiovascular Diseases & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Tianjin University & Chinese Academy of Medical Sciences, Tianjin 300457, China
| | - Qin Yang
- The Institute of Cardiovascular Diseases & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Tianjin University & Chinese Academy of Medical Sciences, Tianjin 300457, China
| | - Yuan-Lu Chen
- Department of Electrophysiology, TEDA International Cardiovascular Hospital, Tianjin University & Chinese Academy of Medical Sciences, Tianjin 300457, China
| | - Hou-Zao Chen
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
| | - Guo-Wei He
- The Institute of Cardiovascular Diseases & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Tianjin University & Chinese Academy of Medical Sciences, Tianjin 300457, China; Department of Surgery, Oregon Health & Science University, Portland, OR 97239-3098, USA.
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Anderson JR, Morin EE, Brayer KJ, Salbato S, Gonzalez Bosc LV, Kanagy NL, Naik JS. Single-cell transcriptomic heterogeneity between conduit and resistance mesenteric arteries in rats. Physiol Genomics 2023; 55:179-193. [PMID: 36912534 PMCID: PMC10085562 DOI: 10.1152/physiolgenomics.00126.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/03/2023] [Accepted: 03/08/2023] [Indexed: 03/14/2023] Open
Abstract
The endothelium contains morphologically similar cells throughout the vasculature, but individual cells along the length of a single vascular tree or in different regional circulations function dissimilarly. When observations made in large arteries are extrapolated to explain the function of endothelial cells (ECs) in the resistance vasculature, only a fraction of these observations are consistent between artery sizes. To what extent endothelial (EC) and vascular smooth muscle cells (VSMCs) from different arteriolar segments of the same tissue differ phenotypically at the single-cell level remains unknown. Therefore, single-cell RNA-seq (10x Genomics) was performed using a 10X Genomics Chromium system. Cells were enzymatically digested from large (>300 µm) and small (<150 µm) mesenteric arteries from nine adult male Sprague-Dawley rats, pooled to create six samples (3 rats/sample, 3 samples/group). After normalized integration, the dataset was scaled before unsupervised cell clustering and cluster visualization using UMAP plots. Differential gene expression analysis allowed us to infer the biological identity of different clusters. Our analysis revealed 630 and 641 differentially expressed genes (DEGs) between conduit and resistance arteries for ECs and VSMCs, respectively. Gene ontology analysis (GO-Biological Processes, GOBP) of scRNA-seq data discovered 562 and 270 pathways for ECs and VSMCs, respectively, that differed between large and small arteries. We identified eight and seven unique ECs and VSMCs subpopulations, respectively, with DEGs and pathways identified for each cluster. These results and this dataset allow the discovery and support of novel hypotheses needed to identify mechanisms that determine the phenotypic heterogeneity between conduit and resistance arteries.
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Affiliation(s)
- Jacob R Anderson
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Emily E Morin
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Kathryn J Brayer
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Sophia Salbato
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Laura V Gonzalez Bosc
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Nancy L Kanagy
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Jay S Naik
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
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Zádor E. The Meeting of Micropeptides with Major Ca 2+ Pumps in Inner Membranes-Consideration of a New Player, SERCA1b. MEMBRANES 2023; 13:274. [PMID: 36984661 PMCID: PMC10058886 DOI: 10.3390/membranes13030274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/20/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Calcium is a major signalling bivalent cation within the cell. Compartmentalization is essential for regulation of calcium mediated processes. A number of players contribute to intracellular handling of calcium, among them are the sarco/endoplasmic reticulum calcium ATP-ases (SERCAs). These molecules function in the membrane of ER/SR pumping Ca2+ from cytoplasm into the lumen of the internal store. Removal of calcium from the cytoplasm is essential for signalling and for relaxation of skeletal muscle and heart. There are three genes and over a dozen isoforms of SERCA in mammals. These can be potentially influenced by small membrane peptides, also called regulins. The discovery of micropeptides has increased in recent years, mostly because of the small ORFs found in long RNAs, annotated formerly as noncoding (lncRNAs). Several excellent works have analysed the mechanism of interaction of micropeptides with each other and with the best known SERCA1a (fast muscle) and SERCA2a (heart, slow muscle) isoforms. However, the array of tissue and developmental expressions of these potential regulators raises the question of interaction with other SERCAs. For example, the most abundant calcium pump in neonatal and regenerating skeletal muscle, SERCA1b has never been looked at with scrutiny to determine whether it is influenced by micropeptides. Further details might be interesting on the interaction of these peptides with the less studied SERCA1b isoform.
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Affiliation(s)
- Ernő Zádor
- Institute of Biochemistry, Albert Szent-Györgyi Faculty of Medicine, University of Szeged, Dóm tér 9, H-6720 Szeged, Hungary
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De Moudt S, Hendrickx JO, De Meyer GRY, Martinet W, Fransen P. Basal Vascular Smooth Muscle Cell Tone in eNOS Knockout Mice Can Be Reversed by Cyclic Stretch and Is Independent of Age. Front Physiol 2022; 13:882527. [PMID: 35574444 PMCID: PMC9096105 DOI: 10.3389/fphys.2022.882527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/11/2022] [Indexed: 11/14/2022] Open
Abstract
Introduction and Aims: Endothelial nitric oxide synthase (eNOS) knockout mice develop pronounced cardiovascular disease. In the present study, we describe the alterations in aortic physiology and biomechanics of eNOS knockout and C57Bl/6 control mice at 2–12 months of age, including a thorough physiological investigation of age and cyclic stretch-dependent VSMC contractility and aortic stiffness. Methods and Results: Peripheral blood pressure and aortic pulse wave velocity were measured in vivo, and aortic biomechanical studies and isometric contractions were investigated ex vivo. Age-dependent progression of aortic stiffness, peripheral hypertension, and aortic contractility in eNOS knockout mice was absent, attenuated, or similar to C57Bl/6 control mice. Voltage-gated calcium channel (VGCC)-dependent calcium influx inversely affected isometric contraction and aortic stiffening by α1-adrenergic stimulation in eNOS knockout mice. Baseline aortic stiffness was selectively reduced in eNOS knockout mice after ex vivo cyclic stretch exposure in an amplitude-dependent manner, which prompted us to investigate cyclic stretch dependent regulation of aortic contractility and stiffness. Aortic stiffness, both in baseline conditions and after activation of vascular smooth muscle cell (VSMC) contraction, was reduced with increasing cyclic stretch amplitude. This cyclic stretch dependency was attenuated with age, although aged eNOS knockout mice displayed better preservation of cyclic stretch-dependency compared to C57Bl/6 control mice. Store operated calcium entry-medicated aortic stiffening as induced by inhibiting sarcoplasmic reticulum calcium ATPase pumps with 10 µM CPA was most pronounced in the aorta of aged mice and at low cyclic stretch amplitude, but independent of eNOS. Basal aortic tonus and VSMC depolarization were highly dependent on eNOS, and were most pronounced at low cyclic stretch, with attenuation at increasing cyclic stretch amplitude. Conclusion: eNOS knockout mice display attenuated progression of arterial disease as compared to C57Bl/6 control mice. Basal VSMC tone in eNOS knockout mice could be reduced by ex vivo exposure to cyclic stretch through stretch-dependent regulation of cytosolic calcium. Both baseline and active aortic stiffness were highly dependent on cyclic stretch regulation, which was more pronounced in young versus aged mice. Other mediators of VSMC contraction and calcium handling were dependent on cyclic stretch mechanotransduction, but independent of eNOS.
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