1
|
Wijnker PJM, Dinani R, van der Laan NC, Algül S, Knollmann BC, Verkerk AO, Remme CA, Zuurbier CJ, Kuster DWD, van der Velden J. Hypertrophic cardiomyopathy dysfunction mimicked in human engineered heart tissue and improved by sodium-glucose cotransporter 2 inhibitors. Cardiovasc Res 2024; 120:301-317. [PMID: 38240646 PMCID: PMC10939456 DOI: 10.1093/cvr/cvae004] [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: 12/01/2022] [Revised: 11/15/2023] [Accepted: 11/29/2023] [Indexed: 03/16/2024] Open
Abstract
AIMS Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy, often caused by pathogenic sarcomere mutations. Early characteristics of HCM are diastolic dysfunction and hypercontractility. Treatment to prevent mutation-induced cardiac dysfunction is lacking. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a group of antidiabetic drugs that recently showed beneficial cardiovascular outcomes in patients with acquired forms of heart failure. We here studied if SGLT2i represent a potential therapy to correct cardiomyocyte dysfunction induced by an HCM sarcomere mutation. METHODS AND RESULTS Contractility was measured of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) harbouring an HCM mutation cultured in 2D and in 3D engineered heart tissue (EHT). Mutations in the gene encoding β-myosin heavy chain (MYH7-R403Q) or cardiac troponin T (TNNT2-R92Q) were investigated. In 2D, intracellular [Ca2+], action potential and ion currents were determined. HCM mutations in hiPSC-CMs impaired relaxation or increased force, mimicking early features observed in human HCM. SGLT2i enhance the relaxation of hiPSC-CMs, to a larger extent in HCM compared to control hiPSC-CMs. Moreover, SGLT2i-effects on relaxation in R403Q EHT increased with culture duration, i.e. hiPSC-CMs maturation. Canagliflozin's effects on relaxation were more pronounced than empagliflozin and dapagliflozin. SGLT2i acutely altered Ca2+ handling in HCM hiPSC-CMs. Analyses of SGLT2i-mediated mechanisms that may underlie enhanced relaxation in mutant hiPSC-CMs excluded SGLT2, Na+/H+ exchanger, peak and late Nav1.5 currents, and L-type Ca2+ current, but indicate an important role for the Na+/Ca2+ exchanger. Indeed, electrophysiological measurements in mutant hiPSC-CM indicate that SGLT2i altered Na+/Ca2+ exchange current. CONCLUSION SGLT2i (canagliflozin > dapagliflozin > empagliflozin) acutely enhance relaxation in human EHT, especially in HCM and upon prolonged culture. SGLT2i may represent a potential therapy to correct early cardiac dysfunction in HCM.
Collapse
Affiliation(s)
- Paul J M Wijnker
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Rafeeh Dinani
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Nico C van der Laan
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Sila Algül
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Arie O Verkerk
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
- Experimental Cardiology, Amsterdam UMC, Academic Medical Centre, Amsterdam, The Netherlands
| | - Carol Ann Remme
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
- Experimental Cardiology, Amsterdam UMC, Academic Medical Centre, Amsterdam, The Netherlands
| | - Coert J Zuurbier
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
- Laboratory for Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Department of Anesthesiology, Amsterdam UMC, Academic Medical Centre, Amsterdam, The Netherlands
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| |
Collapse
|
2
|
Zhong J, Dong J, Ruan W, Duan X. Potential Theranostic Roles of SLC4 Molecules in Human Diseases. Int J Mol Sci 2023; 24:15166. [PMID: 37894847 PMCID: PMC10606849 DOI: 10.3390/ijms242015166] [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: 08/29/2023] [Revised: 09/28/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
The solute carrier family 4 (SLC4) is an important protein responsible for the transport of various ions across the cell membrane and mediating diverse physiological functions, such as the ion transporting function, protein-to-protein interactions, and molecular transduction. The deficiencies in SLC4 molecules may cause multisystem disease involving, particularly, the respiratory system, digestive, urinary, endocrine, hematopoietic, and central nervous systems. Currently, there are no effective strategies to treat these diseases. SLC4 proteins are also found to contribute to tumorigenesis and development, and some of them are regarded as therapeutic targets in quite a few clinical trials. This indicates that SLC4 proteins have potential clinical prospects. In view of their functional characteristics, there is a critical need to review the specific functions of bicarbonate transporters, their related diseases, and the involved pathological mechanisms. We summarize the diseases caused by the mutations in SLC4 family genes and briefly introduce the clinical manifestations of these diseases as well as the current treatment strategies. Additionally, we illustrate their roles in terms of the physiology and pathogenesis that has been currently researched, which might be the future therapeutic and diagnostic targets of diseases and a new direction for drug research and development.
Collapse
Affiliation(s)
| | | | | | - Xiaohong Duan
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, National Clinical Research Center for Oral Disease, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, The Fourth Military Medical University, Xi’an 710032, China; (J.Z.); (J.D.); (W.R.)
| |
Collapse
|
3
|
Quade BN, Parker MD, Occhipinti R. The therapeutic importance of acid-base balance. Biochem Pharmacol 2021; 183:114278. [PMID: 33039418 PMCID: PMC7544731 DOI: 10.1016/j.bcp.2020.114278] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/06/2020] [Indexed: 02/06/2023]
Abstract
Baking soda and vinegar have been used as home remedies for generations and today we are only a mouse-click away from claims that baking soda, lemon juice, and apple cider vinegar are miracles cures for everything from cancer to COVID-19. Despite these specious claims, the therapeutic value of controlling acid-base balance is indisputable and is the basis of Food and Drug Administration-approved treatments for constipation, epilepsy, metabolic acidosis, and peptic ulcers. In this narrative review, we present evidence in support of the current and potential therapeutic value of countering local and systemic acid-base imbalances, several of which do in fact involve the administration of baking soda (sodium bicarbonate). Furthermore, we discuss the side effects of pharmaceuticals on acid-base balance as well as the influence of acid-base status on the pharmacokinetic properties of drugs. Our review considers all major organ systems as well as information relevant to several clinical specialties such as anesthesiology, infectious disease, oncology, dentistry, and surgery.
Collapse
Affiliation(s)
- Bianca N Quade
- Department of Physiology and Biophysics, The State University of New York, The University at Buffalo, Buffalo, NY 14203, USA
| | - Mark D Parker
- Department of Physiology and Biophysics, The State University of New York, The University at Buffalo, Buffalo, NY 14203, USA; Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA; State University of New York Eye Institute, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Rossana Occhipinti
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA.
| |
Collapse
|
4
|
Alimadadi A, Manandhar I, Aryal S, Munroe PB, Joe B, Cheng X. Machine learning-based classification and diagnosis of clinical cardiomyopathies. Physiol Genomics 2020; 52:391-400. [PMID: 32744882 DOI: 10.1152/physiolgenomics.00063.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) are two common types of cardiomyopathies leading to heart failure. Accurate diagnostic classification of different types of cardiomyopathies is critical for precision medicine in clinical practice. In this study, we hypothesized that machine learning (ML) can be used as a novel diagnostic approach to analyze cardiac transcriptomic data for classifying clinical cardiomyopathies. RNA-Seq data of human left ventricle tissues were collected from 41 DCM patients, 47 ICM patients, and 49 nonfailure controls (NF) and tested using five ML algorithms: support vector machine with radial kernel (svmRadial), neural networks with principal component analysis (pcaNNet), decision tree (DT), elastic net (ENet), and random forest (RF). Initial ML classifications achieved ~93% accuracy (svmRadial) for NF vs. DCM, ~82% accuracy (RF) for NF vs. ICM, and ~80% accuracy (ENet and svmRadial) for DCM vs. ICM. Next, 50 highly contributing genes (HCGs) for classifying NF and DCM, 68 HCGs for classifying NF and ICM, and 59 HCGs for classifying DCM and ICM were selected for retraining ML models. Impressively, the retrained models achieved ~90% accuracy (RF) for NF vs. DCM, ~90% accuracy (pcaNNet) for NF vs. ICM, and ~85% accuracy (pcaNNet and RF) for DCM vs. ICM. Pathway analyses further confirmed the involvement of those selected HCGs in cardiac dysfunctions such as cardiomyopathies, cardiac hypertrophies, and fibrosis. Overall, our study demonstrates the promising potential of using artificial intelligence via ML modeling as a novel approach to achieve a greater level of precision in diagnosing different types of cardiomyopathies.
Collapse
Affiliation(s)
- Ahmad Alimadadi
- Bioinformatics & Artificial Intelligence Laboratory, Center for Hypertension and Precision Medicine, Program in Physiological Genomics, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio.,Bioinformatics Program, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Ishan Manandhar
- Bioinformatics & Artificial Intelligence Laboratory, Center for Hypertension and Precision Medicine, Program in Physiological Genomics, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio.,Bioinformatics Program, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Sachin Aryal
- Bioinformatics & Artificial Intelligence Laboratory, Center for Hypertension and Precision Medicine, Program in Physiological Genomics, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio.,Bioinformatics Program, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Patricia B Munroe
- Clinical Pharmacology, William Harvey Research Institute & National Institute of Health Research Barts Cardiovascular Biomedical Research Centre, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Bina Joe
- Bioinformatics & Artificial Intelligence Laboratory, Center for Hypertension and Precision Medicine, Program in Physiological Genomics, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio.,Bioinformatics Program, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| | - Xi Cheng
- Bioinformatics & Artificial Intelligence Laboratory, Center for Hypertension and Precision Medicine, Program in Physiological Genomics, Department of Physiology and Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio
| |
Collapse
|
5
|
Vairamani K, Prasad V, Wang Y, Huang W, Chen Y, Medvedovic M, Lorenz JN, Shull GE. NBCe1 Na +-HCO3 - cotransporter ablation causes reduced apoptosis following cardiac ischemia-reperfusion injury in vivo. World J Cardiol 2018; 10:97-109. [PMID: 30344957 PMCID: PMC6189072 DOI: 10.4330/wjc.v10.i9.97] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 07/05/2018] [Accepted: 07/16/2018] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the hypothesis that cardiomyocyte-specific loss of the electrogenic NBCe1 Na+-HCO3- cotransporter is cardioprotective during in vivo ischemia-reperfusion (IR) injury.
METHODS An NBCe1 (Slc4a4 gene) conditional knockout mouse (KO) model was prepared by gene targeting. Cardiovascular performance of wildtype (WT) and cardiac-specific NBCe1 KO mice was analyzed by intraventricular pressure measurements, and changes in cardiac gene expression were determined by RNA Seq analysis. Response to in vivo IR injury was analyzed after 30 min occlusion of the left anterior descending artery followed by 3 h of reperfusion.
RESULTS Loss of NBCe1 in cardiac myocytes did not impair cardiac contractility or relaxation under basal conditions or in response to β-adrenergic stimulation, and caused only limited changes in gene expression patterns, such as those for electrical excitability. However, following ischemia and reperfusion, KO heart sections exhibited significantly fewer apoptotic nuclei than WT sections.
CONCLUSION These studies indicate that cardiac-specific loss of NBCe1 does not impair cardiovascular performance, causes only minimal changes in gene expression patterns, and protects against IR injury in vivo .
Collapse
Affiliation(s)
- Kanimozhi Vairamani
- Division of Oncology, Cancer and Blood Diseases Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229-3026, United States
| | - Vikram Prasad
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229-3039, United States
| | - Yigang Wang
- Department of Pathology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0529, United States
| | - Wei Huang
- Department of Pathology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0529, United States
| | - Yinhua Chen
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229-3039, United States
| | - Mario Medvedovic
- Department of Environmental Health, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0056, United States
| | - John N Lorenz
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0575, United States
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, College of Medicine, Cincinnati, OH 45267-0524, United States
| |
Collapse
|
6
|
Parker MD. Mouse models of SLC4-linked disorders of HCO 3--transporter dysfunction. Am J Physiol Cell Physiol 2018; 314:C569-C588. [PMID: 29384695 DOI: 10.1152/ajpcell.00301.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The SLC4 family Cl-/[Formula: see text] cotransporters (NBCe1, NBCe2, NBCn1, and NBCn2) contribute to a variety of vital physiological processes including pH regulation and epithelial fluid secretion. Accordingly, their dysfunction can have devastating effects. Disorders such as epilepsy, hemolytic anemia, glaucoma, hearing loss, osteopetrosis, and renal tubular acidosis are all genetically linked to SLC4-family gene loci. This review summarizes how studies of Slc4-modified mice have enhanced our understanding of the etiology of SLC4-linked pathologies and the interpretation of genetic linkage studies. The review also surveys the novel disease signs exhibited by Slc4-modified mice which could either be considered to presage their description in humans, or to highlight interspecific differences. Finally, novel Slc4-modified mouse models are proposed, the study of which may further our understanding of the basis and treatment of SLC4-linked disorders of [Formula: see text]-transporter dysfunction.
Collapse
Affiliation(s)
- Mark D Parker
- Department of Physiology and Biophysics, The State University of New York: The University at Buffalo , Buffalo, New York.,Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo: The State University of New York , Buffalo, New York.,State University of New York Eye Institutes, University at Buffalo: The State University of New York , Buffalo, New York
| |
Collapse
|
7
|
Loss-of-activity-mutation in the cardiac chloride-bicarbonate exchanger AE3 causes short QT syndrome. Nat Commun 2017; 8:1696. [PMID: 29167417 PMCID: PMC5700076 DOI: 10.1038/s41467-017-01630-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 10/04/2017] [Indexed: 01/16/2023] Open
Abstract
Patients with short QT syndrome (SQTS) may present with syncope, ventricular fibrillation or sudden cardiac death. Six SQTS susceptibility genes, encoding cation channels, explain <25% of SQTS cases. Here we identify a missense mutation in the anion exchanger (AE3)-encoding SLC4A3 gene in two unrelated families with SQTS. The mutation causes reduced surface expression of AE3 and reduced membrane bicarbonate transport. Slc4a3 knockdown in zebrafish causes increased cardiac pHi, short QTc, and reduced systolic duration, which is rescued by wildtype but not mutated SLC4A3. Mechanistic analyses suggest that an increase in pHi and decrease in [Cl-]i shortened the action potential duration. However, other mechanisms may also play a role. Altered anion transport represents a mechanism for development of arrhythmia and may provide new therapeutic possibilities.
Collapse
|
8
|
Vairamani K, Wang HS, Medvedovic M, Lorenz JN, Shull GE. RNA SEQ Analysis Indicates that the AE3 Cl -/HCO 3- Exchanger Contributes to Active Transport-Mediated CO 2 Disposal in Heart. Sci Rep 2017; 7:7264. [PMID: 28779178 PMCID: PMC5544674 DOI: 10.1038/s41598-017-07585-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/29/2017] [Indexed: 02/06/2023] Open
Abstract
Loss of the AE3 Cl−/HCO3− exchanger (Slc4a3) in mice causes an impaired cardiac force-frequency response and heart failure under some conditions but the mechanisms are not known. To better understand the functions of AE3, we performed RNA Seq analysis of AE3-null and wild-type mouse hearts and evaluated the data with respect to three hypotheses (CO2 disposal, facilitation of Na+-loading, and recovery from an alkaline load) that have been proposed for its physiological functions. Gene Ontology and PubMatrix analyses of differentially expressed genes revealed a hypoxia response and changes in vasodilation and angiogenesis genes that strongly support the CO2 disposal hypothesis. Differential expression of energy metabolism genes, which indicated increased glucose utilization and decreased fatty acid utilization, were consistent with adaptive responses to perturbations of O2/CO2 balance in AE3-null myocytes. Given that the myocardium is an obligate aerobic tissue and consumes large amounts of O2, the data suggest that loss of AE3, which has the potential to extrude CO2 in the form of HCO3−, impairs O2/CO2 balance in cardiac myocytes. These results support a model in which the AE3 Cl−/HCO3− exchanger, coupled with parallel Cl− and H+-extrusion mechanisms and extracellular carbonic anhydrase, is responsible for active transport-mediated disposal of CO2.
Collapse
Affiliation(s)
- Kanimozhi Vairamani
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Hong-Sheng Wang
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Mario Medvedovic
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - John N Lorenz
- Department of Cellular and Molecular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267, USA.
| |
Collapse
|
9
|
Downs LM, Webster AR, Moore AT, Michaelides M, Ali RR, Hardcastle AJ, Mellersh CS. Investigation of SLA4A3 as a candidate gene for human retinal disease. J Negat Results Biomed 2016; 15:11. [PMID: 27211793 PMCID: PMC4876561 DOI: 10.1186/s12952-016-0054-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 04/14/2016] [Indexed: 11/10/2022] Open
Abstract
SLC4A3 has been shown to cause retinal degeneration in a genetically engineered knockout mouse, and in a naturally occurring form of canine progressive retinal atrophy considered to be the equivalent of retinitis pigmentosa in humans (RP). This study was undertaken to investigate if SLC4A3 coding variants were implicated in human retinal degeneration. SLC4A3 exons were amplified and sequenced in 200 patients with autosomal recessive retinal degeneration who had no known molecular diagnosis for their condition, which included 197 unrelated individuals with suspected RP and three individuals with other forms of retinal disease. Three rare variants were identified that were predicted to be potentially pathogenic, however each variant was heterozygous in a single patient and therefore not considered disease-causing in isolation. Of these three variants, SNP-3 was the rarest, with an allele frequency of 7.06 x 10(-5) (>46,000 exomes from the ExAC database). In conclusion, no compound heterozygous or homozygous potentially pathogenic variants were identified that would account for recessive RP or retinal degeneration in this cohort, however the possibility remains that the rare variants identified could be acting with as yet undiscovered mutations in introns or regulatory regions. SLC4A3 remains an excellent candidate gene for human retinal degeneration, and with the advent of whole exome and whole genome sequencing of cohorts of molecularly unsolved patients with syndromic and non-syndromic forms of retinal degeneration, SLC4A3 may yet be implicated in human disease.
Collapse
Affiliation(s)
- Louise M Downs
- Kennel Club Genetics Centre, Animal Health Trust, Newmarket, UK. .,Present Address: Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, USA.
| | - Andrew R Webster
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, City Road, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, City Road, London, UK
| | - Michel Michaelides
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, City Road, London, UK
| | | | | | | |
Collapse
|
10
|
SERCA2 Haploinsufficiency in a Mouse Model of Darier Disease Causes a Selective Predisposition to Heart Failure. BIOMED RESEARCH INTERNATIONAL 2015; 2015:251598. [PMID: 26064889 PMCID: PMC4433638 DOI: 10.1155/2015/251598] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/18/2014] [Accepted: 12/23/2014] [Indexed: 12/28/2022]
Abstract
Null mutations in one copy of ATP2A2, the gene encoding sarco/endoplasmic reticulum Ca(2+)-ATPase isoform 2 (SERCA2), cause Darier disease in humans, a skin condition involving keratinocytes. Cardiac function appears to be unimpaired in Darier disease patients, with no evidence that SERCA2 haploinsufficiency itself causes heart disease. However, SERCA2 deficiency is widely considered a contributing factor in heart failure. We therefore analyzed Atp2a2 heterozygous mice to determine whether SERCA2 haploinsufficiency can exacerbate specific heart disease conditions. Despite reduced SERCA2a levels in heart, Atp2a2 heterozygous mice resembled humans in exhibiting normal cardiac physiology. When subjected to hypothyroidism or crossed with a transgenic model of reduced myofibrillar Ca(2+)-sensitivity, SERCA2 deficiency caused no enhancement of the disease state. However, when combined with a transgenic model of increased myofibrillar Ca(2+)-sensitivity, SERCA2 haploinsufficiency caused rapid onset of hypertrophy, decompensation, and death. These effects were associated with reduced expression of the antiapoptotic Hax1, increased levels of the proapoptotic genes Chop and Casp12, and evidence of perturbations in energy metabolism. These data reveal myofibrillar Ca(2+)-sensitivity to be an important determinant of the cardiac effects of SERCA2 haploinsufficiency and raise the possibility that Darier disease patients are more susceptible to heart failure under certain conditions.
Collapse
|
11
|
Ablation of plasma membrane Ca(2+)-ATPase isoform 4 prevents development of hypertrophy in a model of hypertrophic cardiomyopathy. J Mol Cell Cardiol 2014; 77:53-63. [PMID: 25280781 DOI: 10.1016/j.yjmcc.2014.09.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 09/23/2014] [Accepted: 09/24/2014] [Indexed: 11/20/2022]
Abstract
The mechanisms linking the expression of sarcomeric mutant proteins to the development of pathological hypertrophy in hypertrophic cardiomyopathy (HCM) remain poorly understood. We investigated the role of the plasma membrane Ca(2+)-ATPase PMCA4 in the HCM phenotype using a transgenic model that expresses mutant (Glu180Gly) α-tropomyosin (Tm180) in heart. Immunoblot analysis revealed that cardiac PMCA4 expression was upregulated early in Tm180 disease pathogenesis. This was accompanied by an increase in levels of the L-type Ca(2+)-channel, which is implicated in pathological hypertrophy. When Tm180 mice were crossed with a PMCA4-null line, loss of PMCA4 caused the abrogation of hypertrophy in Tm180/PMCA4-null double mutant mice. RT-PCR analysis of Tm180/PMCA4-null hearts revealed blunting of the fetal program and reversion of pro-fibrotic Col1a1 and Col3a1 gene expression to wild-type levels. This was accompanied by evidence of reduced L-type Ca(2+)-channel expression, and diminished calcineurin activity. Expression of the metabolic substrate transporters glucose transporter 4 and carnitine palmitoyltransferase 1b was preserved and Tm180-related changes in mRNA levels of various contractile stress-related proteins including the cardiac ankyrin protein CARP and the N2B isoform of titin were reversed in Tm180/PMCA4-null hearts. cGMP levels were increased and phosphorylation of vasodilator-stimulated phosphoprotein was elevated in Tm180/PMCA4-null hearts. These changes were associated with a sharp reduction in left ventricular end-diastolic pressure in Tm180/PMCA4-null hearts, which occurred despite persistence of Tm180-related impairment of relaxation dynamics. These results reveal a novel and specific role for PMCA4 in the Tm180 hypertrophic phenotype, with the "protective" effects of PMCA4 deficiency encompassing multiple determinants of HCM-related hypertrophy.
Collapse
|
12
|
Alka K, Casey JR. Bicarbonate transport in health and disease. IUBMB Life 2014; 66:596-615. [PMID: 25270914 DOI: 10.1002/iub.1315] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/10/2014] [Indexed: 12/28/2022]
Abstract
Bicarbonate (HCO3(-)) has a central place in human physiology as the waste product of mitochondrial energy production and for its role in pH buffering throughout the body. Because bicarbonate is impermeable to membranes, bicarbonate transport proteins are necessary to enable control of bicarbonate levels across membranes. In humans, 14 bicarbonate transport proteins, members of the SLC4 and SLC26 families, function by differing transport mechanisms. In addition, some anion channels and ZIP metal transporters contribute to bicarbonate movement across membranes. Defective bicarbonate transport leads to diseases, including systemic acidosis, brain dysfunction, kidney stones, and hypertension. Altered expression levels of bicarbonate transporters in patients with breast, colon, and lung cancer suggest an important role of these transporters in cancer.
Collapse
Affiliation(s)
- Kumari Alka
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | | |
Collapse
|
13
|
Wang HS, Chen Y, Vairamani K, Shull GE. Critical role of bicarbonate and bicarbonate transporters in cardiac function. World J Biol Chem 2014; 5:334-345. [PMID: 25225601 PMCID: PMC4160527 DOI: 10.4331/wjbc.v5.i3.334] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 03/06/2014] [Accepted: 05/19/2014] [Indexed: 02/05/2023] Open
Abstract
Bicarbonate is one of the major anions in mammalian tissues and extracellular fluids. Along with accompanying H+, HCO3- is generated from CO2 and H2O, either spontaneously or via the catalytic activity of carbonic anhydrase. It serves as a component of the major buffer system, thereby playing a critical role in pH homeostasis. Bicarbonate can also be utilized by a variety of ion transporters, often working in coupled systems, to transport other ions and organic substrates across cell membranes. The functions of HCO3- and HCO3--transporters in epithelial tissues have been studied extensively, but their functions in heart are less well understood. Here we review studies of the identities and physiological functions of Cl-/HCO3- exchangers and Na+/HCO3- cotransporters of the SLC4A and SLC26A families in heart. We also present RNA Seq analysis of their cardiac mRNA expression levels. These studies indicate that slc4a3 (AE3) is the major Cl-/HCO3- exchanger and plays a protective role in heart failure, and that Slc4a4 (NBCe1) is the major Na+/HCO3- cotransporter and affects action potential duration. In addition, previous studies show that HCO3- has a positive inotropic effect in the perfused heart that is largely independent of effects on intracellular Ca2+. The importance of HCO3- in the regulation of contractility is supported by experiments showing that isolated cardiomyocytes exhibit sharply enhanced contractility, with no change in Ca2+ transients, when switched from Hepes-buffered to HCO3-- buffered solutions. These studies demonstrate that HCO3- and HCO3--handling proteins play important roles in the regulation of cardiac function.
Collapse
|
14
|
Adkins GB, Curtis MJ. Potential role of cardiac chloride channels and transporters as novel therapeutic targets. Pharmacol Ther 2014; 145:67-75. [PMID: 25160469 DOI: 10.1016/j.pharmthera.2014.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/01/2014] [Indexed: 02/06/2023]
Abstract
The heart and blood vessels express a range of anion currents (e.g. ICl.PKA) and symporter/antiporters (e.g. Cl(-)/HCO3(-) exchanger) that translocate chloride (Cl(-)). They have been proposed to contribute to a variety of physiological processes including cellular excitability, cell volume homeostasis and apoptosis. Additionally there is evidence that Cl(-) currents or transporters may play a role in cardiac pathophysiology. Arrhythmogenesis, the process of cardiac ischaemic preconditioning, and the adaptive remodelling process in myocardial hypertrophy and heart failure have all been linked to such channels or transporters. We have explored the possibility that selective targeting of one or more of these may provide benefit in cardiovascular disease. Existing evidence points to an emerging role of cardiac cell anion channels as potential therapeutic targets, the 'disease-specificity' of which may represent a substantial improvement on current targets. However, the limitations of current techniques hitherto applied (such as developmental compensation in gene-modified animals) and pharmacological agents (which do not at present possess sufficient selectivity for the adequate probing of function) have thus far hindered translation to the introduction of new therapy.
Collapse
|
15
|
Sowah D, Brown BF, Quon A, Alvarez BV, Casey JR. Resistance to cardiomyocyte hypertrophy in ae3-/- mice, deficient in the AE3 Cl-/HCO3- exchanger. BMC Cardiovasc Disord 2014; 14:89. [PMID: 25047106 PMCID: PMC4120010 DOI: 10.1186/1471-2261-14-89] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/16/2014] [Indexed: 12/21/2022] Open
Abstract
Background Cardiac hypertrophy is central to the etiology of heart failure. Understanding the molecular pathways promoting cardiac hypertrophy may identify new targets for therapeutic intervention. Sodium-proton exchanger (NHE1) activity and expression levels in the heart are elevated in many models of hypertrophy through protein kinase C (PKC)/MAPK/ERK/p90RSK pathway stimulation. Sustained NHE1 activity, however, requires an acid-loading pathway. Evidence suggests that the Cl−/HCO3− exchanger, AE3, provides this acid load. Here we explored the role of AE3 in the hypertrophic growth cascade of cardiomyocytes. Methods AE3-deficient (ae3−/−) mice were compared to wildtype (WT) littermates to examine the role of AE3 protein in the development of cardiomyocyte hypertrophy. Mouse hearts were assessed by echocardiography. As well, responses of cultured cardiomyocytes to hypertrophic stimuli were measured. pH regulation capacity of ae3−/− and WT cardiomyocytes was assessed in cultured cells loaded with the pH-sensitive dye, BCECF-AM. Results ae3−/− mice were indistinguishable from wild type (WT) mice in terms of cardiovascular performance. Stimulation of ae3−/− cardiomyocytes with hypertrophic agonists did not increase cardiac growth or reactivate the fetal gene program. ae3−/− mice are thus protected from pro-hypertrophic stimulation. Steady state intracellular pH (pHi) in ae3−/− cardiomyocytes was not significantly different from WT, but the rate of recovery of pHi from imposed alkalosis was significantly slower in ae3−/− cardiomyocytes. Conclusions These data reveal the importance of AE3-mediated Cl−/HCO3− exchange in cardiovascular pH regulation and the development of cardiomyocyte hypertrophy. Pharmacological antagonism of AE3 is an attractive approach in the treatment of cardiac hypertrophy.
Collapse
Affiliation(s)
| | | | | | | | - Joseph R Casey
- Department of Biochemistry and Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 2H7, Canada.
| |
Collapse
|
16
|
Molecular cloning and functional characterization of zebrafish Slc4a3/Ae3 anion exchanger. Pflugers Arch 2014; 466:1605-18. [PMID: 24668450 DOI: 10.1007/s00424-014-1494-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Revised: 02/24/2014] [Accepted: 03/04/2014] [Indexed: 12/15/2022]
Abstract
The zebrafish genome encodes two slc4a1 genes, one expressed in erythroid tissues and the other in the HR (H(+)-ATPase-rich) type of embryonic skin ionocytes, and two slc4a2 genes, one in proximal pronephric duct and the other in several extrarenal tissues of the embryo. We now report cDNA cloning and functional characterization of zebrafish slc4a3/ae3 gene products. The single ae3 gene on chromosome 9 generates at least two low-abundance ae3 transcripts differing only in their 5'-untranslated regions and encoding a single definitive Ae3 polypeptide of 1170 amino acids. The 7 kb upstream of the apparent initiator Met in ae3 exon 3 comprises multiple diverse, mobile repeat elements which disrupt and appear to truncate the Ae3 N-terminal amino acid sequence that would otherwise align with brain Ae3 of other species. Embryonic ae3 mRNA expression was detected by whole mount in situ hybridization only in fin buds at 24-72 hpf, but was detectable by RT-PCR across a range of embryonic and adult tissues. Epitope-tagged Ae3 polypeptide was expressed at or near the surface of Xenopus oocytes, and mediated low rates of DIDS-sensitive (36)Cl(-)/Cl(-) exchange in influx and efflux assays. As previously reported for Ae2 polypeptides, (36)Cl(-) transport by Ae3 was inhibited by both extracellular and intracellular acidic pH, and stimulated by alkaline pH. However, zebrafish Ae3 differed from Ae2 polypeptides in its insensitivity to NH4Cl and to hypertonicity. We conclude that multiple repeat elements have disrupted the 5'-end of the zebrafish ae3 gene, associated with N-terminal truncation of the protein and reduced anion transport activity.
Collapse
|
17
|
Prasad V, Lorenz JN, Lasko VM, Nieman ML, Al Moamen NJ, Shull GE. Loss of the AE3 Cl(-)/HCO(-) 3 exchanger in mice affects rate-dependent inotropy and stress-related AKT signaling in heart. Front Physiol 2013; 4:399. [PMID: 24427143 PMCID: PMC3875869 DOI: 10.3389/fphys.2013.00399] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 12/19/2013] [Indexed: 01/12/2023] Open
Abstract
Cl(-)/HCO(-) 3 exchangers are expressed abundantly in cardiac muscle, suggesting that HCO(-) 3 extrusion serves an important function in heart. Mice lacking Anion Exchanger Isoform 3 (AE3), a major cardiac Cl(-)/HCO(-) 3 exchanger, appear healthy, but loss of AE3 causes decompensation in a hypertrophic cardiomyopathy (HCM) model. Using intra-ventricular pressure analysis, in vivo pacing, and molecular studies we identified physiological and biochemical changes caused by loss of AE3 that may contribute to decompensation in HCM. AE3-null mice had normal cardiac contractility under basal conditions and after β-adrenergic stimulation, but pacing of hearts revealed that frequency-dependent inotropy was blunted, suggesting that AE3-mediated HCO(-) 3 extrusion is required for a robust force-frequency response (FFR) during acute biomechanical stress in vivo. Modest changes in expression of proteins that affect Ca(2+)-handling were observed, but Ca(2+)-transient analysis of AE3-null myocytes showed normal twitch-amplitude and Ca(2+)-clearance. Phosphorylation and expression of several proteins implicated in HCM and FFR, including phospholamban (PLN), myosin binding protein C, and troponin I were not altered in hearts of paced AE3-null mice; however, phosphorylation of Akt, which plays a central role in mechanosensory signaling, was significantly higher in paced AE3-null hearts than in wild-type controls and phosphorylation of AMPK, which is affected by Akt and is involved in energy metabolism and some cases of HCM, was reduced. These data show loss of AE3 leads to impaired rate-dependent inotropy, appears to affect mechanical stress-responsive signaling, and reduces activation of AMPK, which may contribute to decompensation in heart failure.
Collapse
Affiliation(s)
- Vikram Prasad
- Departments of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - John N Lorenz
- Departments of Cellular and Molecular Physiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - Valerie M Lasko
- Departments of Cellular and Molecular Physiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - Michelle L Nieman
- Departments of Cellular and Molecular Physiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
| | - Nabeel J Al Moamen
- Genetic Laboratory, Department of Pathology, Salmaniya Medical Complex Manama, Bahrain
| | - Gary E Shull
- Departments of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine Cincinnati, OH, USA
| |
Collapse
|
18
|
Prasad V, Lorenz JN, Miller ML, Vairamani K, Nieman ML, Wang Y, Shull GE. Loss of NHE1 activity leads to reduced oxidative stress in heart and mitigates high-fat diet-induced myocardial stress. J Mol Cell Cardiol 2013; 65:33-42. [PMID: 24080184 PMCID: PMC3883452 DOI: 10.1016/j.yjmcc.2013.09.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 09/16/2013] [Accepted: 09/21/2013] [Indexed: 12/23/2022]
Abstract
Acute inhibition of the NHE1 Na(+)/H(+) exchanger protects against ischemia-reperfusion injury and chronic inhibition attenuates development of cardiac hypertrophy and failure. To determine the cardiac effects of chronic inhibition of NHE1 under non-pathological conditions we used NHE1-null mice as a model of long-term NHE1 inhibition. Cardiovascular performance was relatively normal in Nhe1(-/-) mice although cardiac contractility and relaxation were slightly improved in mutant mice of the FVB/N background. GSH levels and GSH:GSSG ratios were elevated in Nhe1(-/-) hearts indicating an enhanced redox potential. Consistent with a reduced need for antioxidant protection, expression of heat shock proteins Hsp60 and Hsp25 was lower in Nhe1(-/-) hearts. Similarly, expression of mitochondrial superoxide dismutase 2 was reduced, with no increase in expression of other ROS scavenging enzymes. GLUT1 levels were increased in Nhe1(-/-) hearts, the number of lipid droplets in myocytes was reduced, and PDK4 expression was refractory to high-fat diet-induced upregulation observed in wild-type hearts. High-fat diet-induced stress was attenuated in Nhe1(-/-) hearts, as indicated by smaller increases in phosphorylation of Hsp25 and α-B crystallin, and there was better preservation of insulin sensitivity, as evidenced by PKB/Akt phosphorylation. Plasma glucose and insulin levels were lower and high-fat diet-induced hepatic lipid accumulation was reduced in Nhe1(-/-) mice, demonstrating extracardiac effects of NHE1 ablation. These data indicate that long-term ablation of NHE1 activity increases the redox potential, mitigates high-fat diet-induced myocardial stress and fatty liver disease, leads to better preservation of insulin sensitivity, and may alter both cardiac and systemic metabolic substrate handling in mice.
Collapse
Affiliation(s)
- Vikram Prasad
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - John N. Lorenz
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Marian L. Miller
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Kanimozhi Vairamani
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Michelle L. Nieman
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Yigang Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Gary E. Shull
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| |
Collapse
|
19
|
Schulz EM, Wilder T, Chowdhury SAK, Sheikh HN, Wolska BM, Solaro RJ, Wieczorek DF. Decreasing tropomyosin phosphorylation rescues tropomyosin-induced familial hypertrophic cardiomyopathy. J Biol Chem 2013; 288:28925-35. [PMID: 23960072 DOI: 10.1074/jbc.m113.466466] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Studies indicate that tropomyosin (Tm) phosphorylation status varies in different mouse models of cardiac disease. Investigation of basal and acute cardiac function utilizing a mouse model expressing an α-Tm protein that cannot be phosphorylated (S283A) shows a compensated hypertrophic phenotype with significant increases in SERCA2a expression and phosphorylation of phospholamban Ser-16 (Schulz, E. M., Correll, R. N., Sheikh, H. N., Lofrano-Alves, M. S., Engel, P. L., Newman, G., Schultz Jel, J., Molkentin, J. D., Wolska, B. M., Solaro, R. J., and Wieczorek, D. F. (2012) J. Biol. Chem. 287, 44478-44489). With these results, we hypothesized that decreasing α-Tm phosphorylation may be beneficial in the context of a chronic, intrinsic stressor. To test this hypothesis, we utilized the familial hypertrophic cardiomyopathy (FHC) α-Tm E180G model (Prabhakar, R., Boivin, G. P., Grupp, I. L., Hoit, B., Arteaga, G., Solaro, R. J., and Wieczorek, D. F. (2001) J. Mol. Cell. Cardiol. 33, 1815-1828). These FHC hearts are characterized by increased heart:body weight ratios, fibrosis, increased myofilament Ca(2+) sensitivity, and contractile defects. The FHC mice die by 6-8 months of age. We generated mice expressing both the E180G and S283A mutations and found that the hypertrophic phenotype was rescued in the α-Tm E180G/S283A double mutant transgenic animals; these mice exhibited no signs of cardiac hypertrophy and displayed improved cardiac function. These double mutant transgenic hearts showed increased phosphorylation of phospholamban Ser-16 and Thr-17 compared with the α-Tm E180G mice. This is the first study to demonstrate that decreasing phosphorylation of tropomyosin can rescue a hypertrophic cardiomyopathic phenotype.
Collapse
Affiliation(s)
- Emily M Schulz
- From the Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267
| | | | | | | | | | | | | |
Collapse
|
20
|
Rajan S, Pena JR, Jegga AG, Aronow BJ, Wolska BM, Wieczorek DF. Microarray analysis of active cardiac remodeling genes in a familial hypertrophic cardiomyopathy mouse model rescued by a phospholamban knockout. Physiol Genomics 2013; 45:764-73. [PMID: 23800848 DOI: 10.1152/physiolgenomics.00023.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Familial hypertrophic cardiomyopathy (FHC) is a disease characterized by ventricular hypertrophy, fibrosis, and aberrant systolic and/or diastolic function. Our laboratories have previously developed two mouse models that affect cardiac performance. One mouse model encodes an FHC-associated mutation in α-tropomyosin: Glu → Gly at amino acid 180, designated as Tm180. These mice display a phenotype that is characteristic of FHC, including severe cardiac hypertrophy with fibrosis and impaired physiological performance. The other model was a gene knockout of phospholamban (PLN KO), a regulator of calcium uptake in the sarcoplasmic reticulum of cardiomyocytes; these hearts exhibit hypercontractility with no pathological abnormalities. Previous work in our laboratories shows that when mice were genetically crossed between the PLN KO and Tm180, the progeny (PLN KO/Tm180) display a rescued hypertrophic phenotype with improved morphology and cardiac function. To understand the changes in gene expression that occur in these models undergoing cardiac remodeling (Tm180, PLN KO, PLN KO/Tm180, and nontransgenic control mice), we conducted microarray analyses of left ventricular tissue at 4 and 12 mo of age. Expression profiling reveals that 1,187 genes changed expression in direct response to the three genetic models. With these 1,187 genes, 11 clusters emerged showing normalization of transcript expression in the PLN KO/Tm180 hearts. In addition, 62 transcripts are highly involved in suppression of the hypertrophic phenotype. Confirmation of the microarray analysis was conducted by quantitative RT-PCR. These results provide insight into genes that alter expression during cardiac remodeling and are active during modulation of the cardiomyopathic phenotype.
Collapse
Affiliation(s)
- Sudarsan Rajan
- Department of Molecular Genetics, Biochemistry, & Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0524, USA
| | | | | | | | | | | |
Collapse
|
21
|
Hersch M, Peter B, Kang HM, Schüpfer F, Abriel H, Pedrazzini T, Eskin E, Beckmann JS, Bergmann S, Maurer F. Mapping genetic variants associated with beta-adrenergic responses in inbred mice. PLoS One 2012; 7:e41032. [PMID: 22859963 PMCID: PMC3409184 DOI: 10.1371/journal.pone.0041032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 06/16/2012] [Indexed: 01/11/2023] Open
Abstract
β-blockers and β-agonists are primarily used to treat cardiovascular diseases. Inter-individual variability in response to both drug classes is well recognized, yet the identity and relative contribution of the genetic players involved are poorly understood. This work is the first genome-wide association study (GWAS) addressing the values and susceptibility of cardiovascular-related traits to a selective β1-blocker, Atenolol (ate), and a β-agonist, Isoproterenol (iso). The phenotypic dataset consisted of 27 highly heritable traits, each measured across 22 inbred mouse strains and four pharmacological conditions. The genotypic panel comprised 79922 informative SNPs of the mouse HapMap resource. Associations were mapped by Efficient Mixed Model Association (EMMA), a method that corrects for the population structure and genetic relatedness of the various strains. A total of 205 separate genome-wide scans were analyzed. The most significant hits include three candidate loci related to cardiac and body weight, three loci for electrocardiographic (ECG) values, two loci for the susceptibility of atrial weight index to iso, four loci for the susceptibility of systolic blood pressure (SBP) to perturbations of the β-adrenergic system, and one locus for the responsiveness of QTc (p<10−8). An additional 60 loci were suggestive for one or the other of the 27 traits, while 46 others were suggestive for one or the other drug effects (p<10−6). Most hits tagged unexpected regions, yet at least two loci for the susceptibility of SBP to β-adrenergic drugs pointed at members of the hypothalamic-pituitary-thyroid axis. Loci for cardiac-related traits were preferentially enriched in genes expressed in the heart, while 23% of the testable loci were replicated with datasets of the Mouse Phenome Database (MPD). Altogether these data and validation tests indicate that the mapped loci are relevant to the traits and responses studied.
Collapse
Affiliation(s)
- Micha Hersch
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Bastian Peter
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Hyun Min Kang
- Department of Computer Science and Department of Human Genetics, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biostatistics, Center for Statistical Genetics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Fanny Schüpfer
- Service of Medical Genetics, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Hugues Abriel
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Thierry Pedrazzini
- Department of Medicine, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Eleazar Eskin
- Department of Computer Science and Department of Human Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jacques S. Beckmann
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
- Service of Medical Genetics, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
| | - Sven Bergmann
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Fabienne Maurer
- Service of Medical Genetics, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
- * E-mail:
| |
Collapse
|
22
|
Chen HP, He M, Mei ZJ, Huang QR, Peng W, Huang M. Anion exchanger 3 is required for sasanquasaponin to inhibit ischemia/reperfusion-induced elevation of intracellular Cl− concentration and to elicit cardioprotection. J Cell Biochem 2011; 112:2803-12. [DOI: 10.1002/jcb.23195] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
23
|
Rindler TN, Dostanic I, Lasko VM, Nieman ML, Neumann JC, Lorenz JN, Lingrel JB. Knockout of the Na,K-ATPase α₂-isoform in the cardiovascular system does not alter basal blood pressure but prevents ACTH-induced hypertension. Am J Physiol Heart Circ Physiol 2011; 301:H1396-404. [PMID: 21856916 DOI: 10.1152/ajpheart.00121.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The α(2)-isoform of Na,K-ATPase (α(2)) is thought to play a role in blood pressure regulation, but the specific cell type(s) involved have not been identified. Therefore, it is important to study the role of the α(2) in individual cell types in the cardiovascular system. The present study demonstrates the role of vascular smooth muscle α(2) in the regulation of cardiovascular hemodynamics. To accomplish this, we developed a mouse model utilizing the Cre/LoxP system to generate a cell type-specific knockout of the α(2) in vascular smooth muscle cells using the SM22α Cre. We achieved a 90% reduction in the α(2)-expression in heart and vascular smooth muscle in the knockout mice. Interestingly, tail-cuff blood pressure analysis reveals that basal systolic blood pressure is unaffected by the knockout of α(2) in the knockout mice. However, knockout mice do fail to develop ACTH-induced hypertension, as seen in wild-type mice, following 5 days of treatment with ACTH (Cortrosyn; wild type = 119.0 ± 6.8 mmHg; knockout = 103.0 ± 2.0 mmHg). These results demonstrate that α(2)-expression in heart and vascular smooth muscle is not essential for regulation of basal systolic blood pressure, but α(2) is critical for blood pressure regulation under chronic stress such as ACTH-induced hypertension.
Collapse
Affiliation(s)
- Tara N Rindler
- Department of Molecular Genetics, Biochemistry, and Microbiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | | | | | | | | | | | | |
Collapse
|