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Moral-Sanz J, Lewis SA, MacMillan S, Meloni M, McClafferty H, Viollet B, Foretz M, Del-Pozo J, Mark Evans A. AMPK deficiency in smooth muscles causes persistent pulmonary hypertension of the new-born and premature death. Nat Commun 2022; 13:5034. [PMID: 36028487 PMCID: PMC9418192 DOI: 10.1038/s41467-022-32568-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/05/2022] [Indexed: 11/10/2022] Open
Abstract
AMPK has been reported to facilitate hypoxic pulmonary vasoconstriction but, paradoxically, its deficiency precipitates pulmonary hypertension. Here we show that AMPK-α1/α2 deficiency in smooth muscles promotes persistent pulmonary hypertension of the new-born. Accordingly, dual AMPK-α1/α2 deletion in smooth muscles causes premature death of mice after birth, associated with increased muscularisation and remodeling throughout the pulmonary arterial tree, reduced alveolar numbers and alveolar membrane thickening, but with no oedema. Spectral Doppler ultrasound indicates pulmonary hypertension and attenuated hypoxic pulmonary vasoconstriction. Age-dependent right ventricular pressure elevation, dilation and reduced cardiac output was also evident. KV1.5 potassium currents of pulmonary arterial myocytes were markedly smaller under normoxia, which is known to facilitate pulmonary hypertension. Mitochondrial fragmentation and reactive oxygen species accumulation was also evident. Importantly, there was no evidence of systemic vasculopathy or hypertension in these mice. Moreover, hypoxic pulmonary vasoconstriction was attenuated by AMPK-α1 or AMPK-α2 deletion without triggering pulmonary hypertension.
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Affiliation(s)
- Javier Moral-Sanz
- Centre for Discovery Brain Sciences and Cardiovascular Science, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Sophronia A Lewis
- Centre for Discovery Brain Sciences and Cardiovascular Science, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Sandy MacMillan
- Centre for Discovery Brain Sciences and Cardiovascular Science, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Marco Meloni
- Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Heather McClafferty
- Centre for Discovery Brain Sciences and Cardiovascular Science, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Benoit Viollet
- Université Paris Cité, CNRS, INSERM, Institut Cochin, F-75014, Paris, France
| | - Marc Foretz
- Université Paris Cité, CNRS, INSERM, Institut Cochin, F-75014, Paris, France
| | - Jorge Del-Pozo
- R(D)SVS, University of Edinburgh Easter Bush Campus, EH25 9RG, Roslin, Edinburgh, UK
| | - A Mark Evans
- Centre for Discovery Brain Sciences and Cardiovascular Science, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD, UK.
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2
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Komurcu-Bayrak E, Kalkan MA, Coban N, Ozsait-Selcuk B, Bayrak F. Identification of the pathogenic effects of missense variants causing PRKAG2 cardiomyopathy. Arch Biochem Biophys 2022; 727:109340. [PMID: 35787834 DOI: 10.1016/j.abb.2022.109340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 06/10/2022] [Accepted: 06/23/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Pathogenic missense variants in PRKAG2, the gene for the gamma 2 regulatory subunit of adenosine monophosphate-activated protein kinase (AMPK), cause severe progressive cardiac disease and sudden cardiac death, named PRKAG2 cardiomyopathy. In our previous study, we reported a E506K variant in the PRKAG2 gene that was associated with this disease. This study aimed to functionally characterize the three missense variants (E506K, E506Q, and R531G) of PRKAG2 and determine the possible effects on AMPK activity. METHODS The proband was clinically monitored for eight years. To investigate the functional effects of three missense variants of PRKAG2, in vitro mutagenesis experiments using HEK293 cells with wild and mutant transcripts and proteins were comparatively analyzed using quantitative RT-PCR, immunofluorescence staining, and enzyme-linked immunosorbent assay. RESULTS In the long-term follow-up, the proband was deceased due to progressive heart failure. In the in vitro experimental studies, PRKAG2 was overexpressed after 48 h of transfection in three mutated cells, after which the expression levels of PRKAG2 were regressed to the level of wild-type cells in 3-weeks stably transformed cells, except for the cells with E506K variant. E506K, E506Q, and R531G variants had caused a reduction in the AMPK activity and resulted in the formation of cytoplasmic glycogen deposits. CONCLUSION Three missense variants that alter AMPK activity affect a residue in the CBS4 domain associated with ATP/AMP-binding. Detailed information on the influence of PRKAG2 pathogenic variants on AMPK activity would be helpful to improve the treatment and management of patients with metabolic cardiomyopathy.
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Affiliation(s)
- Evrim Komurcu-Bayrak
- Istanbul University, Aziz Sancar Institute of Experimental Medicine, Department of Genetics, Istanbul, Turkey; Istanbul University, Istanbul Faculty of Medicine, Departments of Medical Genetics, Istanbul, Turkey.
| | - Muhammed Abdulvahid Kalkan
- Istanbul University, Aziz Sancar Institute of Experimental Medicine, Department of Genetics, Istanbul, Turkey; Istanbul University, Institute of Graduate Studies in Health Sciences, Istanbul, Turkey.
| | - Neslihan Coban
- Istanbul University, Aziz Sancar Institute of Experimental Medicine, Department of Genetics, Istanbul, Turkey.
| | - Bilge Ozsait-Selcuk
- Istanbul University, Istanbul Faculty of Medicine, Departments of Medical Genetics, Istanbul, Turkey.
| | - Fatih Bayrak
- Acibadem Altunizade Hospital, Department of Cardiology, Istanbul, Turkey.
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3
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Gong X, Yu P, Wu T, He Y, Zhou K, Hua Y, Lin S, Wang T, Huang H, Li Y. Controversial molecular functions of CBS versus non-CBS domain variants of PRKAG2 in arrhythmia and cardiomyopathy: A case report and literature review. Mol Genet Genomic Med 2022; 10:e1962. [PMID: 35588295 PMCID: PMC9266596 DOI: 10.1002/mgg3.1962] [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: 02/09/2022] [Revised: 04/01/2022] [Accepted: 04/18/2022] [Indexed: 02/05/2023] Open
Abstract
Background PRKAG2 cardiac syndrome is a rare autosomal dominant genetic disorder caused by a PRKAG2 gene variant. There are several major adverse cardiac presentations, including hypertrophic cardiomyopathy (HCM) and life‐threatening arrhythmia. Two cases with pathogenic variants in the PRKAG2 gene are reported here who presents different cardiac phenotypes. Methods Exome sequencing and variant analysis of PRKAG2 were performed to obtain genetic data, and clinical characteristics were determined. Results The first proband was a 9‐month‐old female infant (Case 1), and was identified with severe DCM and resistant heart failure. The second proband was a 10‐year‐old female infant (Case 2), and presented with HCM and ventricular preexcitation. Exome sequencing identified a de novo c.425C > T (p.T142I) heterozygous variant in the PRKAG2 gene for Case 1, and a c.869A > T (p.K290I) for Case 2. The mutated sites in the protein were labeled and identified as p.K290 in the CBS domain and p.T142 in the non‐CBS domain. Differences in the molecular functions of CBS and non‐CBS domains have not been resolved, and variants might lead to the different cardiomyopathy phenotypes. Single‐cell RNA analysis demonstrated similar expression levels of PRKAG2 in cardiomyocytes and conductive tissues. These results suggest that the arrhythmia induced by the PRKAG2 variant was the primary change, and not secondary to cardiomyopathy. Conclusion In summary, this is the first case report to describe a DCM phenotype with early onset in patients possessing a PRKAG2 c.425C > T (p.T142I) pathogenic variant. Our results aid in understanding the molecular function of non‐CBS variants in terms of the disordered sequence of transcripts. Moreover, we used scRNA‐seq to show that electrically conductive cells express a higher level of PRKAG2 than do cardiomyocytes. Therefore, variants in PRKAG2 are expected to also alter the biological function of the conduction system.
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Affiliation(s)
- Xue Gong
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Peiyu Yu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China.,Department of Pediatrics, Chengdu Shangjin Nanfu Hospital, Chengdu, China
| | - Ting Wu
- Department of Ultrasonic Medicine, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yunru He
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Kaiyu Zhou
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yimin Hua
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Sha Lin
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Tao Wang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
| | - He Huang
- Department of Echocardiography, West China Hospital, Sichuan University, Chengdu, China
| | - Yifei Li
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China
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4
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Hypertrophic Cardiomyopathy and Primary Restrictive Cardiomyopathy: Similarities, Differences and Phenocopies. J Clin Med 2021; 10:jcm10091954. [PMID: 34062949 PMCID: PMC8125617 DOI: 10.3390/jcm10091954] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 12/14/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) and primary restrictive cardiomyopathy (RCM) have a similar genetic background as they are both caused mainly by variants in sarcomeric genes. These “sarcomeric cardiomyopathies” also share diastolic dysfunction as the prevalent pathophysiological mechanism. Starting from the observation that patients with HCM and primary RCM may coexist in the same family, a characteristic pathophysiological profile of HCM with restrictive physiology has been recently described and supports the hypothesis that familiar forms of primary RCM may represent a part of the phenotypic spectrum of HCM rather than a different genetic cardiomyopathy. To further complicate this scenario some infiltrative (amyloidosis) and storage diseases (Fabry disease and glycogen storage diseases) may show either a hypertrophic or restrictive phenotype according to left ventricular wall thickness and filling pattern. Establishing a correct etiological diagnosis among HCM, primary RCM, and hypertrophic or restrictive phenocopies is of paramount importance for cascade family screening and therapy.
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5
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Ahamed H, Balegadde AV, Menon S, Menon R, Ramachandran A, Mathew N, Natarajan KU, Nair IR, Kannan R, Shankar M, Mathew OK, Nguyen TT, Gupta R, Stawiski EW, Ramprasad VL, Seshagiri S, Phalke S. Phenotypic expression and clinical outcomes in a South Asian PRKAG2 cardiomyopathy cohort. Sci Rep 2020; 10:20610. [PMID: 33244021 PMCID: PMC7691361 DOI: 10.1038/s41598-020-77124-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/27/2020] [Indexed: 11/09/2022] Open
Abstract
The PRKAG2 syndrome is a rare autosomal dominant phenocopy of sarcomeric hypertrophic cardiomyopathy (HCM), characterized by ventricular pre-excitation, progressive conduction system disease and left ventricular hypertrophy. This study describes the phenotype, genotype and clinical outcomes of a South-Asian PRKAG2 cardiomyopathy cohort over a 7-year period. Clinical, electrocardiographic, echocardiographic, and cardiac MRI data from 22 individuals with PRKAG2 variants (68% men; mean age 39.5 ± 18.1 years), identified at our HCM centre were studied prospectively. At initial evaluation, all of the patients were in NYHA functional class I or II. The maximum left ventricular wall thickness was 22.9 ± 8.7 mm and left ventricular ejection fraction was 53.4 ± 6.6%. Left ventricular hypertrophy was present in 19 individuals (86%) at baseline. 17 patients had an WPW pattern (77%). After a mean follow-up period of 7 years, 2 patients had undergone accessory pathway ablation, 8 patients (36%) underwent permanent pacemaker implantation (atrio-ventricular blocks-5; sinus node disease-2), 3 patients developed atrial fibrillation, 11 patients (50%) developed progressive worsening in NYHA functional class, and 6 patients (27%) experienced sudden cardiac death or equivalent. PRKAG2 cardiomyopathy must be considered in patients with HCM and progressive conduction system disease.
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Affiliation(s)
- Hisham Ahamed
- Amrita Institute of Medical Sciences and Research, Kochi, India.
| | | | - Shilpa Menon
- Amrita Institute of Medical Sciences and Research, Kochi, India
| | | | | | - Navin Mathew
- Amrita Institute of Medical Sciences and Research, Kochi, India
| | - K U Natarajan
- Amrita Institute of Medical Sciences and Research, Kochi, India
| | | | - Rajesh Kannan
- Amrita Institute of Medical Sciences and Research, Kochi, India
| | | | | | | | | | | | | | - Somasekar Seshagiri
- Genentech Inc., South San Francisco, USA.,SciGenom Research Foundation, Kochi, India
| | - Sameer Phalke
- MedGenome Labs, Bangalore, India. .,SciGenom Labs Pvt Ltd, Kochi, India.
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6
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Hu J, Tang B, Wang J, Huang K, Wang Y, Lu S, Gowreesunkur HB, Wang Y, Wu D, Mayala HA, Wang ZH. Familial Atrial Enlargement, Conduction Disorder and Symmetric Cardiac Hypertrophy Are Early Signs of PRKAG2 R302Q. Curr Med Sci 2020; 40:486-492. [PMID: 32681253 DOI: 10.1007/s11596-020-2207-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 04/16/2020] [Indexed: 11/29/2022]
Abstract
PRKAG2 cardiac syndrome (PS) is a rare inherited disease due to PRKAG2 gene mutation and characterized by Wolff-Parkinson-White syndrome (WPWs), conduction system lesions and myocardial hypertrophy. It can also lead to serious consequences, such as sudden death. But the genetic and clinical heterogeneity makes the early diagnosis of PS difficult. Here we studied a family with familial hypertrophic cardiomyopathy and other diverse manifestations. Gene analysis identified a missense mutation (Arg302Gln) in the five affected subjects of the family. The electrocardiograph performance of the five was composed of sinus bradycardia (SB), WPWs, right bundle branch block (RBBB), atrioventricular block (AVB), left bundle branch block (LBBB), supraventricular tachycardia (SVT) and atrial premature beat (APB). Among them, the youngest one began to show paroxysmal palpitation at the age of nine and was confirmed to have WPWs at 17 years old; two members progressed over time to serious conduction damage, and the proband received a pacemaker at the age of 27 due to AVB. Besides, according to cardiac magnetic resonance and echocardiography, the youngest one showed symmetric hypertrophy; three older members showed asymmetric myocardial hypertrophy characterized with a diffuse pattern of middle-anterior-lateral-inferior wall hypertrophy and especially interventricular septal hypertrophy; all five affected patients showed atrial enlargement regardless of myocardial hypertrophy at an earlier stage. In conclusion, the conduction system disorder, familial atrial enlargement and symmetric cardiac hypertrophy may occur in the early stage of PRKAG2 R302Q mutation.
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Affiliation(s)
- Jing Hu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Ben Tang
- First Clinical School, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jing Wang
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Key Laboratory of Molecular Imaging of Hubei Province, Wuhan, 430022, China
| | - Kun Huang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yan Wang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Shuai Lu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hnkeshsing Baboo Gowreesunkur
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Ya Wang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Di Wu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Henry Anselmo Mayala
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Zhao-Hui Wang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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7
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Hu D, Hu D, Liu L, Barr D, Liu Y, Balderrabano-Saucedo N, Wang B, Zhu F, Xue Y, Wu S, Song B, McManus H, Murphy K, Loes K, Adler A, Monserrat L, Antzelevitch C, Gollob MH, Elliott PM, Barajas-Martinez H. Identification, clinical manifestation and structural mechanisms of mutations in AMPK associated cardiac glycogen storage disease. EBioMedicine 2020; 54:102723. [PMID: 32259713 PMCID: PMC7132172 DOI: 10.1016/j.ebiom.2020.102723] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 02/08/2020] [Accepted: 03/03/2020] [Indexed: 01/25/2023] Open
Abstract
Background Although 21 causative mutations have been associated with PRKAG2 syndrome, our understanding of the syndrome remains incomplete. The aim of this project is to further investigate its unique genetic background, clinical manifestations, and underlying structural changes. Methods We recruited 885 hypertrophic cardiomyopathy (HCM) probands and their families internationally. Targeted next-generation sequencing of sudden cardiac death (SCD) genes was performed. The role of the identified variants was assessed using histological techniques and computational modeling. Findings Twelve PRKAG2 syndrome kindreds harboring 5 distinct variants were identified. The clinical penetrance of 25 carriers was 100.0%. Twenty-two family members died of SCD or heart failure (HF). All probands developed bradycardia (HRmin, 36.3 ± 9.8 bpm) and cardiac conduction defects, and 33% had evidence of atrial fibrillation/paroxysmal supraventricular tachycardia (PSVT) and 67% had ventricular preexcitation, respectively. Some carriers presented with apical hypertrophy, hypertension, hyperlipidemia, and renal insufficiency. Histological study revealed reduced AMPK activity and major cardiac channels in the heart tissue with K485E mutation. Computational modelling suggests that K485E disrupts the salt bridge connecting the β and γ subunits of AMPK, R302Q/P decreases the binding affinity for ATP, T400N and H401D alter the orientation of H383 and R531 residues, thus altering nucleotide binding, and N488I and L341S lead to structural instability in the Bateman domain, which disrupts the intramolecular regulation. Interpretation Including 4 families with 3 new mutations, we describe a cohort of 12 kindreds with PRKAG2 syndrome with novel pathogenic mechanisms by computational modelling. Severe clinical cardiac phenotypes may be developed, including HF, requiring close follow-up.
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Affiliation(s)
- Dan Hu
- Department of Cardiology and Cardiovascular Research Institute, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan 430060, China; Hubei Key Laboratory of Cardiology, Wuhan 430060, China.
| | - Dong Hu
- Center for Stem Cell Research and Application, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Liwen Liu
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Daniel Barr
- Department of Chemistry, University of Mary, 7500 University Drive, Bismarck, ND, USA
| | - Yang Liu
- Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou 510080, China
| | | | - Bo Wang
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Feng Zhu
- Clinic Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China; Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Yumei Xue
- Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou 510080, China
| | - Shulin Wu
- Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou 510080, China
| | - BaoLiang Song
- College of Life Sciences, Wuhan University, Wuhan, China
| | - Heather McManus
- Department of Chemistry and Biochemistry, Utica College, Utica, NY, USA
| | - Katherine Murphy
- Department of Chemistry, University of Mary, 7500 University Drive, Bismarck, ND, USA
| | - Katherine Loes
- Department of Chemistry, University of Mary, 7500 University Drive, Bismarck, ND, USA
| | - Arnon Adler
- Department of Physiology and the Peter Munk Cardiovascular Molecular Medicine Laboratory, Toronto General Hospital, University of Toronto, Toronto, ON, Canada
| | | | - Charles Antzelevitch
- Lankenau Institute for Medical Research, Wynnewood, PA, USA; Lankenau Heart Institute, Sidney Kimmel College of Medicine, Thomas Jefferson University, USA
| | - Michael H Gollob
- Department of Physiology and the Peter Munk Cardiovascular Molecular Medicine Laboratory, Toronto General Hospital, University of Toronto, Toronto, ON, Canada
| | - Perry M Elliott
- University College London and St. Bartholomew's Hospital, London, United Kingdom
| | - Hector Barajas-Martinez
- Lankenau Institute for Medical Research, Wynnewood, PA, USA; Lankenau Heart Institute, Sidney Kimmel College of Medicine, Thomas Jefferson University, USA
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8
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Gorla SR, Raja KR, Garg A, Barbouth DS, Rusconi PG. Infantile Onset Hypertrophic Cardiomyopathy Secondary to PRKAG2 Gene Mutation is Associated with Poor Prognosis. J Pediatr Genet 2018; 7:180-184. [PMID: 30430036 DOI: 10.1055/s-0038-1657763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 04/24/2018] [Indexed: 10/14/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is the second most prevalent form of cardiomyopathy in children. The etiology of the HCM is heterogeneous, so is the age of onset of symptoms. The HCM associated with metabolic disorders and genetic syndromes presents early in childhood. There are very few case reports of early-onset infantile HCM secondary to the PRKAG2 gene. Here, we report a case of HCM in a neonate diagnosed prenatally and eventually diagnosed with a missense mutation in the PRKAG2 gene.
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Affiliation(s)
- Sudheer R Gorla
- Division of Pediatric Cardiology, Department of Pediatrics, Jackson Memorial Hospital, University of Miami/Miller School of Medicine, Miami, Florida, United States
| | - Kishore R Raja
- Division of Pediatric Cardiology, Department of Pediatrics, Jackson Memorial Hospital, University of Miami/Miller School of Medicine, Miami, Florida, United States
| | - Ashish Garg
- Division of Pediatric Cardiology, Department of Pediatrics, Jackson Memorial Hospital, University of Miami/Miller School of Medicine, Miami, Florida, United States
| | - Deborah S Barbouth
- Department of Human Genetics, Dr. John T. Macdonald Foundation, University of Miami/Miller School of Medicine, Miami, Florida, United States
| | - Paolo G Rusconi
- Division of Pediatric Cardiology, Department of Pediatrics, Jackson Memorial Hospital, University of Miami/Miller School of Medicine, Miami, Florida, United States
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9
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Miyamoto L. Molecular Pathogenesis of Familial Wolff-Parkinson-White Syndrome. THE JOURNAL OF MEDICAL INVESTIGATION 2018; 65:1-8. [PMID: 29593177 DOI: 10.2152/jmi.65.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Familial Wolff-Parkinson-White (WPW) syndrome is an autosomal dominant inherited disease and consists of a small percentage of WPW syndrome which exhibits ventricular pre-excitation by development of accessory atrioventricular pathway. A series of mutations in PRKAG2 gene encoding gamma2 subunit of 5'AMP-activated protein kinase (AMPK) has been identified as the cause of familial WPW syndrome. AMPK is one of the most important metabolic regulators of carbohydrates and lipids in many types of tissues including cardiac and skeletal muscles. Patients and animals with the mutation in PRKAG2 gene exhibit aberrant atrioventricular conduction associated with cardiac glycogen overload. Recent studies have revealed "novel" significance of canonical pathways leading to glycogen synthesis and provided us profound insights into molecular mechanism of the regulation of glycogen metabolism by AMPK. This review focuses on the molecular basis of the pathogenesis of cardiac abnormality due to PRKAG2 mutation and will provide current overviews of the mechanism of glycogen regulation by AMPK. J. Med. Invest. 65:1-8, February, 2018.
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10
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Abstract
In humans, dominant mutations in the gene encoding the regulatory γ2-subunit of AMP-activated protein kinase (PRKAG2) result in a highly penetrant phenotype dominated by cardiac features: left ventricular hypertrophy, ventricular pre-excitation, atrial tachyarrhythmia, cardiac conduction disease, and myocardial glycogen storage. The discovery of a link between the cell's fundamental energy sensor, AMPK, and inherited cardiac disease catalyzed intense interest into the biological role of AMPK in the heart. In this chapter, we provide an introduction to the spectrum of human disease resulting from pathogenic variants in PRKAG2, outlining its discovery, clinical genetics, and current perspectives on its pathogenesis and highlighting mechanistic insights derived through the evaluation of disease models. We also present a clinical perspective on the major components of the cardiomyopathy associated with mutations in PRKAG2, together with less commonly described extracardiac features, its prognosis, and principles of management.
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Affiliation(s)
- Arash Yavari
- Experimental Therapeutics, Radcliffe Department of Medicine, University of Oxford, Oxford, UK. .,Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK. .,The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
| | - Dhruv Sarma
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.,The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Eduardo B Sternick
- Instituto de Pós-Graduação, Faculdade de Ciências Médicas de Minas Gerais, Belo Horizonte, Brazil
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11
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Xu Y, Gray A, Hardie DG, Uzun A, Shaw S, Padbury J, Phornphutkul C, Tseng YT. A novel, de novo mutation in the PRKAG2 gene: infantile-onset phenotype and the signaling pathway involved. Am J Physiol Heart Circ Physiol 2017; 313:H283-H292. [PMID: 28550180 PMCID: PMC5582920 DOI: 10.1152/ajpheart.00813.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 05/15/2017] [Accepted: 05/19/2017] [Indexed: 01/08/2023]
Abstract
PRKAG2 encodes the γ2-subunit isoform of 5'-AMP-activated protein kinase (AMPK), a heterotrimeric enzyme with major roles in the regulation of energy metabolism in response to cellular stress. Mutations in PRKAG2 have been implicated in a unique hypertrophic cardiomyopathy (HCM) characterized by cardiac glycogen overload, ventricular preexcitation, and hypertrophy. We identified a novel, de novo PRKAG2 mutation (K475E) in a neonate with prenatal onset of HCM. We aimed to investigate the cellular impact, signaling pathways involved, and therapeutic options for K475E mutation using cells stably expressing human wild-type (WT) or the K475E mutant. In human embryonic kidney-293 cells, the K475E mutation induced a marked increase in the basal phosphorylation of T172 and AMPK activity, reduced sensitivity to AMP in allosteric activation, and a loss of response to phenformin. In H9c2 cardiomyocytes, the K475E mutation induced inhibition of AMPK and reduced the response to phenformin and increases in the phosphorylation of p70S6 kinase (p70S6K) and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1). Primary fibroblasts from the patient with the K475E mutation also showed marked increases in the phosphorylation of p70S6K and 4E-BP1 compared with those from age-matched, nondiseased controls. Moreover, overexpression of K475E induced hypertrophy in H9c2 cells, which was effectively reversed by treatment with rapamycin. Taken together, we have identified a novel, de novo infantile-onset PRKAG2 mutation causing HCM. Our study suggests the K475E mutation induces alteration in basal AMPK activity and results in a hypertrophy phenotype involving the mechanistic target of rapamycin signaling pathway, which can be reversed with rapamycin.NEW & NOTEWORTHY We identified a novel, de novo PRKAG2 mutation (K475E) in the cystathionine β-synthase 3 repeat, a region critical for AMP binding but with no previous reported mutation. Our data suggest the mutation affects AMP-activated protein kinase activity, activates cell growth pathways, and results in cardiac hypertrophy, which can be reversed with rapamycin.
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MESH Headings
- AMP-Activated Protein Kinases/chemistry
- AMP-Activated Protein Kinases/genetics
- AMP-Activated Protein Kinases/metabolism
- Adenosine Monophosphate/metabolism
- Cardiomyopathy, Hypertrophic/drug therapy
- Cardiomyopathy, Hypertrophic/enzymology
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/physiopathology
- Carrier Proteins/metabolism
- Case-Control Studies
- DNA Mutational Analysis
- Enzyme Activation
- Fibroblasts/enzymology
- Fibroblasts/pathology
- Genetic Predisposition to Disease
- HEK293 Cells
- Humans
- Infant, Newborn
- Intracellular Signaling Peptides and Proteins
- Models, Molecular
- Mutation, Missense
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/enzymology
- Myocytes, Cardiac/pathology
- Phenformin/pharmacology
- Phenotype
- Phosphoproteins/metabolism
- Phosphorylation
- Protein Conformation
- Protein Kinase Inhibitors/pharmacology
- Ribosomal Protein S6 Kinases, 70-kDa/metabolism
- Signal Transduction/drug effects
- Sirolimus/pharmacology
- Structure-Activity Relationship
- TOR Serine-Threonine Kinases/antagonists & inhibitors
- TOR Serine-Threonine Kinases/metabolism
- Transfection
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Affiliation(s)
- Yanchun Xu
- Women & Infants Hospital of Rhode Island, Providence, Rhode Island
- The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - A Gray
- College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - D Grahame Hardie
- College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Alper Uzun
- Women & Infants Hospital of Rhode Island, Providence, Rhode Island
- The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Sunil Shaw
- Women & Infants Hospital of Rhode Island, Providence, Rhode Island
- The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - James Padbury
- Women & Infants Hospital of Rhode Island, Providence, Rhode Island
- The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Chanika Phornphutkul
- Hasbro Children's Hospital, Providence, Rhode Island; and
- The Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Yi-Tang Tseng
- Women & Infants Hospital of Rhode Island, Providence, Rhode Island;
- The Warren Alpert Medical School of Brown University, Providence, Rhode Island
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12
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Abstract
The AMP-activated protein kinase (AMPK) is a key regulator of cellular and whole-body energy homeostasis, which acts to restore energy homoeostasis whenever cellular energy charge is depleted. Over the last 2 decades, it has become apparent that AMPK regulates several other cellular functions and has specific roles in cardiovascular tissues, acting to regulate cardiac metabolism and contractile function, as well as promoting anticontractile, anti-inflammatory, and antiatherogenic actions in blood vessels. In this review, we discuss the role of AMPK in the cardiovascular system, including the molecular basis of mutations in AMPK that alter cardiac physiology and the proposed mechanisms by which AMPK regulates vascular function under physiological and pathophysiological conditions.
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Affiliation(s)
- Ian P Salt
- From the Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Scotland, United Kingdom (I.P.S.); and Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Scotland, United Kingdom (D.G.H.).
| | - D Grahame Hardie
- From the Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Scotland, United Kingdom (I.P.S.); and Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Scotland, United Kingdom (D.G.H.)
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13
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Thevenon J, Laurent G, Ader F, Laforêt P, Klug D, Duva Pentiah A, Gouya L, Maurage CA, Kacet S, Eicher JC, Albuisson J, Desnos M, Bieth E, Duboc D, Martin L, Réant P, Picard F, Bonithon-Kopp C, Gautier E, Binquet C, Thauvin-Robinet C, Faivre L, Bouvagnet P, Charron P, Richard P. High prevalence of arrhythmic and myocardial complications in patients with cardiac glycogenosis due to PRKAG2 mutations. Europace 2017; 19:651-659. [PMID: 28431061 DOI: 10.1093/europace/euw067] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 02/23/2016] [Indexed: 12/20/2022] Open
Abstract
AIMS Mutations in PRKAG2, the gene encoding for the γ2 subunit of 5'-AMP-activated protein kinase (AMPK), are responsible for an autosomal dominant glycogenosis with a cardiac presentation, associating hypertrophic cardiomyopathy (HCM), ventricular pre-excitation (VPE), and progressive heart block. The aim of this study was to perform a retrospective time-to-event study of the clinical manifestations associated with PRKAG2 mutations. METHODS AND RESULTS A cohort of 34 patients from 9 families was recruited between 2001 and 2010. DNA were sequenced on all exons and flanking sequences of the PRKAG2 gene using Sanger sequencing. Overall, four families carried the recurrent p.Arg302Gln mutation, and the five others carried private mutations among which three had never been reported. In the total cohort, at 40 years of age, the risk of developing HCM was 61%, VPE 70%, conduction block 22%, and sudden cardiac death (SCD) 20%. The global survival at 60 years of age was 66%. Thirty-two per cent of patients (N = 10) required a device implantation (5 pacemakers and 5 defibrillators) at a median age of 66 years, and two patients required heart transplant. Only one patient presented with significant skeletal muscle symptoms. No significant differences regarding the occurrence of VPE, ablation complications, or death incidence were observed between different mutations. CONCLUSION This study of patients with PRKAG2 mutations provides a more comprehensive view of the natural history of this disease and demonstrates a high risk of cardiac complications. Early recognition of this disease appears important to allow an appropriate management.
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Affiliation(s)
- Julien Thevenon
- Centre de Génétique et Centre de Référence "Anomalies du Développement et Syndromes Malformatifs", Hôpital d'Enfants, CHU Dijon, Dijon, France
| | - Gabriel Laurent
- Service de Rythmologie et Insuffisance Cardiaque, Hôpital du Bocage, Centre Hospitalo-Universitaire de Dijon, Dijon, France
- Laboratoire LE2I UMR CNRS 5158, Université de Bourgogne, 9 avenue Alain Savary, Dijon, France
| | - Flavie Ader
- AP-HP, UF Cardiogénétique et Myogénétique, Service de Biochimie Métabolique, Groupe Hospitalier Pitié-Salpêtrière 47-83 boulevard de l'Hôpital, Paris cedex 13 75651, France
| | - Pascal Laforêt
- AP-HP, Centre de Référence de pathologie neuromusculaire Paris-Est, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Didier Klug
- Hôpital Cardiologique, Bd du Pr Leclercq 59037, Lille, France
| | | | - Laurent Gouya
- INSERM U773, Centre de Recherche Biomédicale Bichat Beaujon CRB3, Université Paris 7 Denis Diderot, site Bichat, Paris, France
| | - Claude Alain Maurage
- Université Lille Nord de France, USDL, EA 1056, Lille F-59000, France
- Département de Pathologie, Hôpital Universitaire de Lille, Lille F-59000, France
- INSERM U837, Lille F-59000, France
| | - Salem Kacet
- Hôpital Cardiologique, Bd du Pr Leclercq 59037, Lille, France
| | - Jean-Christophe Eicher
- Service de Rythmologie et Insuffisance Cardiaque, Hôpital du Bocage, Centre Hospitalo-Universitaire de Dijon, Dijon, France
| | - Juliette Albuisson
- INSERM, UMRS_970, Paris Cardiovascular Research Center, Paris, France
- AP-HP, Département de génétique, Hôpital européen Georges-Pompidou, 20, rue Leblanc, Paris 75015, France
- Inserm U 633, faculté de médecine, université Paris-5, Paris 75015, France
| | - Michel Desnos
- INSERM, UMRS_970, Paris Cardiovascular Research Center, Paris, France
- AP-HP, Département de génétique, Hôpital européen Georges-Pompidou, 20, rue Leblanc, Paris 75015, France
- Inserm U 633, faculté de médecine, université Paris-5, Paris 75015, France
| | - Eric Bieth
- Department of Medical Genetics, Hôpital Purpan, Toulouse, France
| | - Denis Duboc
- AP-HP, Service de Cardiologie, Hôpital Cochin, Paris, France
| | - Laurent Martin
- Laboratoire d'anatomopathologie, Plateau technique de Biologie, CHU de Dijon, Dijon, France
| | - Patricia Réant
- Service de Cardiologie, Hôpital Haut-Lévèque, Pessac, France
| | - François Picard
- Service de Cardiologie, Hôpital Haut-Lévèque, Pessac, France
| | - Claire Bonithon-Kopp
- Centre d'investigation clinique-épidémiologie clinique/essais cliniques, CHU, Dijon, France
| | - Elodie Gautier
- Centre d'investigation clinique-épidémiologie clinique/essais cliniques, CHU, Dijon, France
| | - Christine Binquet
- Centre d'investigation clinique-épidémiologie clinique/essais cliniques, CHU, Dijon, France
| | - Christel Thauvin-Robinet
- Centre de Génétique et Centre de Référence "Anomalies du Développement et Syndromes Malformatifs", Hôpital d'Enfants, CHU Dijon, Dijon, France
| | - Laurence Faivre
- Centre de Génétique et Centre de Référence "Anomalies du Développement et Syndromes Malformatifs", Hôpital d'Enfants, CHU Dijon, Dijon, France
| | - Patrice Bouvagnet
- Service médico-chirurgical Cardiologie Pédiatrique et Congénitale Adulte, Laboratoire Cardiogénétique, CHU de Lyon HCL-GH Est-Hôpital Louis Pradel, 69677 BRON CEDEX, et EA4173 Université Lyon 1 et Hôpital du Nord-Ouest, Lyon, France
| | - Philippe Charron
- AP-HP, Centre de référence des maladies cardiaques héréditaires, Hôpital Ambroise Paré, Boulogne-Billancourt, Université de Versailles Saint Quentin en Yvelines, Paris, France
- AP-HP, Centre de référence des maladies cardiaques héréditaires, Inserm UMRS1166, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Pascale Richard
- AP-HP, UF Cardiogénétique et Myogénétique, Service de Biochimie Métabolique, Groupe Hospitalier Pitié-Salpêtrière 47-83 boulevard de l'Hôpital, Paris cedex 13 75651, France
- AP-HP, Centre de référence des maladies cardiaques héréditaires, Inserm UMRS1166, Hôpital de la Pitié-Salpêtrière, Paris, France
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14
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Porto AG, Brun F, Severini GM, Losurdo P, Fabris E, Taylor MRG, Mestroni L, Sinagra G. Clinical Spectrum of PRKAG2 Syndrome. Circ Arrhythm Electrophysiol 2016; 9:e003121. [PMID: 26729852 DOI: 10.1161/circep.115.003121] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Andrea Giuseppe Porto
- Cardiovascular Department "Ospedali Riuniti and University of Trieste", IRCCS Burlo Garofolo, Trieste, Italy
| | - Francesca Brun
- Cardiovascular Department "Ospedali Riuniti and University of Trieste", IRCCS Burlo Garofolo, Trieste, Italy
| | - Giovanni Maria Severini
- Molecular Medicine Department, Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy
| | - Pasquale Losurdo
- Cardiovascular Department "Ospedali Riuniti and University of Trieste", IRCCS Burlo Garofolo, Trieste, Italy
| | - Enrico Fabris
- Cardiovascular Department "Ospedali Riuniti and University of Trieste", IRCCS Burlo Garofolo, Trieste, Italy
| | - Matthew R G Taylor
- Cardiovascular Institute and Adult Medical Genetics, Department of Medicine, University of Colorado Denver, Aurora, CO
| | - Luisa Mestroni
- Cardiovascular Institute and Adult Medical Genetics, Department of Medicine, University of Colorado Denver, Aurora, CO
| | - Gianfranco Sinagra
- Cardiovascular Department "Ospedali Riuniti and University of Trieste", IRCCS Burlo Garofolo, Trieste, Italy
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15
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Abstract
AMPK is an evolutionary conserved energy sensor involved in the regulation of energy metabolism. Based on biochemical studies, AMPK has brought much of interest in recent years due to its potential impact on metabolic disorders. Suitable animal models are therefore essential to promote our understanding of the molecular and functional roles of AMPK but also to bring novel information for the development of novel therapeutic strategies. The organism systems include pig (Sus scrofa), mouse (Mus musculus), fly (Drosophila melanogaster), worm (Caenorhabditis elegans), and fish (Danio rerio) models. These animal models have provided reliable experimental evidence demonstrating the crucial role of AMPK in the regulation of metabolism but also of cell polarity, autophagy, and oxidative stress. In this chapter, we update the new development in the generation and application of animal models for the study of AMPK biology. We also discuss recent breakthroughs from studies in mice, flies, and worms showing how AMPK has a primary role in initiating or promoting pathological or beneficial impact on health.
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Affiliation(s)
- Benoit Viollet
- INSERM U1016, Institut Cochin, Paris, France. .,CNRS UMR 8104, Paris, France. .,Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
| | - Marc Foretz
- INSERM U1016, Institut Cochin, Paris, France.,CNRS UMR 8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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16
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Zhang BL, Ye Z, Xu RL, You XH, Qin YW, Wu H, Cao J, Zhang JL, Zheng X, Zhao XX. Overexpression of G100S mutation in PRKAG2 causes Wolff-Parkinson-White syndrome in zebrafish. Clin Genet 2013; 86:287-91. [PMID: 23992123 DOI: 10.1111/cge.12267] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/28/2013] [Accepted: 08/28/2013] [Indexed: 11/29/2022]
Abstract
The Wolff-Parkinson-White (WPW) syndrome was believed to be associated with PRKAG2 gene mutations. In this study, we verified the pathopoiesis of G100S mutation, a novel mutation only discovered in Chinese patients with WPW, in cardiac disorder. Similar to R302Q, when overexpressed PRKAG2 G100S mutant in zebrafish, we observed a thicker heart wall, detected a decreased AMPK enzymatic activity by tissue AMPK kinase activity colorimetric technique, as well as examined an increased glycogen storage in heart wall using the method for periodic acid-Schiff staining, in comparison with the zebrafish without exogenous PRKAG2 (mock) or with wild-type PRKAG2 (WT). Taken together, we concluded PRKAG2 G100S mutation might contribute to impair the AMP-activated protein kinase function, which resulted in increased cardiac glycogen storage, serving as a pathogenesis for WPW syndrome in Chinese.
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Affiliation(s)
- B L Zhang
- Department of Cardiovascular Diseases, Changhai Hospital, Second Military Medical University, Shanghai, China
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17
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Identification and functional analysis of a novel PRKAG2 mutation responsible for Chinese PRKAG2 cardiac syndrome reveal an important role of non-CBS domains in regulating the AMPK pathway. J Cardiol 2013; 62:241-8. [PMID: 23778007 DOI: 10.1016/j.jjcc.2013.04.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 02/28/2013] [Accepted: 04/12/2013] [Indexed: 11/22/2022]
Abstract
BACKGROUND PRKAG2 gene encodes the γ2 regulatory subunit of AMP-activated protein kinase (AMPK) that acts as a sensor of cellular energy status, and its germline mutations are responsible for PRKAG2 cardiac syndrome (PCS). The majority of missense mutations of cystathionine beta-synthase (CBS) domains found in PCS impair the binding activity of PRKAG2 to adenosine derivatives, and therefore lead to PRKAG2 function impairment and AMPK activity alteration, resulting in a familial syndrome of ventricular preexcitation, conduction defects, and cardiac hypertrophy. However, it is unclear about the PRKAG2 mutation in the non-CBS domain. Here, a Chinese family exhibiting the cardiac syndrome associated with a novel heterozygous PRKAG2 mutation (Gly100Ser) mapped to exon 3 encoding a non-CBS domain is described and the function of this novel mutation was investigated in vitro. METHODS The PRKAG2 G100S and R302Q mutations were constructed by a two-step polymerase chain reaction and then transfected into CCL13 cells by lentivirus vectors. Wild-type PRKAG2 gene transfection was used as a negative control. PRKAG2 expression was determined by Western blot. Immunofluorescence was used to localize the intracellular PRKAG2 proteins. MTT assay was performed to explore the effect of mutations on cell proliferation. Periodic acid-Schiff staining was used for detecting glycogen accumulation. AMPK concentration was measured with enzyme-linked immunosorbent assay. RESULTS Our results showed neither intracellular localization of PRKAG2 nor cell growth was altered. In contrast, PRKAG2 protein expression levels were significantly reduced by this mutation. Furthermore, PRKAG2-mediated activity of AMPK was attenuated, resulting in glycogen metabolism dysregulation. These findings revealed that non-CBS domains of PRKAG2 were essential to the regulation of AMPK activity, similar to CBS. CONCLUSIONS Our study ascribes a crucial regulatory role to the novel PRKAG2 G100S mutation, and reiterates that PCS occurs as a consequence of AMPK signaling abnormality caused by PRKAG2 gene mutations.
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18
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Nouira S, Ouarda F, Charfeddine C, Arfa I, Ouragini H, Abid F, Abdelhak S. Clinical and genetic investigation of pediatric cases of Wolff-Parkinson-White syndrome in Tunisian families. Heart Lung 2010; 39:432-6. [PMID: 20561859 DOI: 10.1016/j.hrtlng.2009.10.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2009] [Revised: 09/22/2009] [Accepted: 10/21/2009] [Indexed: 11/25/2022]
Abstract
BACKGROUND Wolff-Parkinson-White (WPW) syndrome is an autosomal-dominant heart disease characterized by an accessory pathway that arises from an aberrant conduction from the atria to the ventricles. Several mutations within the PRKAG2 gene were shown to be responsible for WPW. This gene encodes the γ2 regulatory subunit of adenosine monophosphate (AMP)-activated protein kinase, which functions as a metabolic sensor in cells, responding to cellular energy demands. METHODS This first study of WPW in a North African population comprises the clinical and genetic investigation of 3 Tunisian families, including 11 affected members. The involvement of the PRKAG2 and NKX2-5 genes was investigated. RESULTS Mutation screening showed that with the exception of two already reported single-nucleotide polymorphisms, no mutations were detected within the coding region of PRKAG2 or in the NKX2-5 gene. CONCLUSIONS This study provides further evidence of the genetic heterogeneity of WPW.
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Affiliation(s)
- Sonia Nouira
- Research Unit UR04/SP03 for the Molecular Investigation of Genetic Orphan Diseases, Institut Pasteur de Tunis, Tunis, Belvédère, Tunisia
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19
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Archer SL, Weir EK, Wilkins MR. Basic science of pulmonary arterial hypertension for clinicians: new concepts and experimental therapies. Circulation 2010; 121:2045-66. [PMID: 20458021 DOI: 10.1161/circulationaha.108.847707] [Citation(s) in RCA: 381] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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20
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Banerjee SK, McGaffin KR, Huang XN, Ahmad F. Activation of cardiac hypertrophic signaling pathways in a transgenic mouse with the human PRKAG2 Thr400Asn mutation. Biochim Biophys Acta Mol Basis Dis 2009; 1802:284-91. [PMID: 20005292 DOI: 10.1016/j.bbadis.2009.12.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 11/11/2009] [Accepted: 12/03/2009] [Indexed: 12/12/2022]
Abstract
Human mutations in PRKAG2, the gene encoding the gamma2 subunit of AMP activated protein kinase (AMPK), cause a glycogen storage cardiomyopathy. In a transgenic mouse with cardiac specific expression of the Thr400Asn mutation in PRKAG2 (TG(T400N)), we previously reported initial cardiac hypertrophy (ages 2-8 weeks) followed by dilation and failure (ages 12-20 weeks). We sought to elucidate the molecular mechanisms of cardiac hypertrophy. TG(T400N) mice showed significantly increased cardiac mass/body mass ratios up to approximately 3-fold beginning at age 2 weeks. Cardiac expression of ANP and BNP were approximately 2- and approximately 5-fold higher, respectively, in TG(T400N) relative to wildtype (WT) mice at age 2 weeks. NF-kappaB activity and nuclear translocation of the p50 subunit were increased approximately 2- to 3-fold in TG(T400N) hearts relative to WT during the hypertrophic phase. Phosphorylated Akt and p70S6K were elevated approximately 2-fold as early as age 2 weeks. To ascertain whether these changes in TG(T400N) mice were a consequence of increased AMPK activity, we crossbred TG(T400N) with TG(alpha2DN) mice, which express a dominant negative, kinase dead mutant of the AMPK alpha2 catalytic subunit and have low myocardial AMPK activity. Genetic reversal of AMPK overactivity led to a reduction in hypertrophy, nuclear translocation of NF-kappaB, phosphorylated Akt, and p70S6K. We conclude that inappropriate activation of AMPK secondary to the T400N PRKAG2 mutation is associated with the early activation of NF-kappaB and Akt signaling pathway, which mediates cardiac hypertrophy.
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Affiliation(s)
- Sanjay K Banerjee
- Cardiovascular Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213-2582, USA
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21
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Kelly BP, Russell MW, Hennessy JR, Ensing GJ. Severe hypertrophic cardiomyopathy in an infant with a novel PRKAG2 gene mutation: potential differences between infantile and adult onset presentation. Pediatr Cardiol 2009; 30:1176-9. [PMID: 19787389 DOI: 10.1007/s00246-009-9521-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 08/03/2009] [Indexed: 01/28/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is a heterogeneous disorder characterized by thickening of the heart and an increased incidence of sudden death. This study is aimed to determine the genetic cause of severe cardiac hypertrophy in an infant. An infant was assigned a diagnosis of ventricular preexcitation and severe biventricular HCM requiring septal myectomy. Genetic testing showed a novel heterozygous E506Q mutation of the adenosine monophosphate (AMP)-activated protein kinase (PRKAG2) gene. Endomyocardial biopsy samples did not demonstrate significant glycogen accumulation. Hypertrophic cardiomyopathy due to PRKAG2 mutations may have a degree of cardiac hypertrophy exceeding that expected from observed amounts of glycogen deposition.
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Affiliation(s)
- Brendan P Kelly
- Division of Pediatric Cardiology, University of Michigan, Ann Arbor, USA.
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22
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Akman HO, Sampayo JN, Ross FA, Scott JW, Wilson G, Benson L, Bruno C, Shanske S, Hardie DG, Dimauro S. Fatal infantile cardiac glycogenosis with phosphorylase kinase deficiency and a mutation in the gamma2-subunit of AMP-activated protein kinase. Pediatr Res 2007; 62:499-504. [PMID: 17667862 DOI: 10.1203/pdr.0b013e3181462b86] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A 10-wk-old infant girl with severe hypertrophy of the septal and atrial walls by cardiac ultrasound, developed progressive ventricular wall thickening and died of aspiration pneumonia at 5 mo of age. Postmortem examination revealed ventricular hypertrophy and massive atrial wall thickening due to glycogen accumulation. A skeletal muscle biopsy showed increased free glycogen and decreased activity of phosphorylase b kinase (PHK). The report of a pathogenic mutation (R531Q) in the gene (PRKAG2) encoding the gamma2 subunit of AMP-activated protein kinase (AMPK) in three infants with congenital hypertrophic cardiomyopathy, glycogen storage, and "pseudo PHK deficiency" prompted us to screen this gene in our patient. We found a novel (R384T) heterozygous mutation in PRKAG2, affecting an arginine residue in the N-terminal AMP-binding domain. Like R531Q, this mutation reduces the binding of AMP and ATP to the isolated nucleotide-binding domains, and prevents activation of the heterotrimer by metabolic stress in intact cells. The mutation was not found in DNA from the patient's father, the only available parent, and is likely to have arisen de novo. Our studies confirm that mutations in PRKAG2 can cause fatal infantile cardiomyopathy, often associated with apparent PHK deficiency.
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Affiliation(s)
- Hasan O Akman
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA, and Department of Cardiology, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
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23
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Abstract
AMP-activated protein kinase (AMPK) is a heterotrimeric enzyme that is expressed in most mammalian tissues including cardiac muscle. Among the multiple biological processes influenced by AMPK, regulation of fuel supply and energy-generating pathways in response to the metabolic needs of the organism is fundamental and likely accounts for the remarkable evolutionary conservation of this enzyme complex. By regulating the activity of acetyl-coenzyme A carboxylase, AMPK affects levels of malonyl-coenzyme A, a key energy regulator in the cell. AMPK is generally quiescent under normal conditions but is activated in response to hormonal signals and stresses sufficient to produce an increase in AMP/ATP ratio, such as hypoglycemia, strenuous exercise, anoxia, and ischemia. Once active, muscle AMPK enhances uptake and oxidative metabolism of fatty acids as well as increases glucose transport and glycolysis. Data from AMPK deficiency models suggest that AMPK activity might influence the pathophysiology and therapy of diabetes and increase heart tolerance to ischemia. Effects that are not as well understood include AMPK regulation of transcription. Different AMPK isoforms are found in distinct locations within the cell and have distinct functions in different tissues. A principal mode of AMPK activation is phosphorylation by upstream kinases (eg, LKB1). These kinases have a fundamental role in cell-cycle regulation and protein synthesis, suggesting involvement in a number of human disorders including cardiac hypertrophy, apoptosis, cancer, and atherosclerosis. The physiological role played by AMPK during health and disease is far from being clearly defined. Naturally occurring mutations affecting the nucleotide-sensing modules in the regulatory gamma subunit of AMPK lead to enzyme dysregulation and inappropriate activation under resting conditions. Glycogen accumulation ensues, leading to human disease manifesting as cardiac hypertrophy, accessory atrioventricular connections, and degeneration of the physiological conduction system. Whether AMPK is a key participant or bystander in other disease states and whether its selective manipulation may significantly benefit these conditions remain important questions.
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Affiliation(s)
- Michael Arad
- Heart Institute, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Israel
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