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Nilsson KH, Henning P, Wu J, Sjögren K, Lerner UH, Ohlsson C, Movérare-Skrtic S. GREM2 inactivation increases trabecular bone mass in mice. Sci Rep 2024; 14:12967. [PMID: 38839844 PMCID: PMC11153596 DOI: 10.1038/s41598-024-63439-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 05/29/2024] [Indexed: 06/07/2024] Open
Abstract
Osteoporosis is a common skeletal disease affecting millions of individuals world-wide, with an increased risk of fracture, and a decreased quality of life. Despite its well-known consequences, the etiology of osteoporosis and optimal treatment methods are not fully understood. Human genetic studies have identified genetic variants within the FMN2/GREM2 locus to be associated with trabecular volumetric bone mineral density (vBMD) and vertebral and forearm fractures, but not with cortical bone parameters. GREM2 is a bone morphogenetic protein (BMP) antagonist. In this study, we employed Grem2-deficient mice to investigate whether GREM2 serves as the plausible causal gene for the fracture signal at the FMN2/GREM2 locus. We observed that Grem2 is moderately expressed in bone tissue and particularly in osteoblasts. Complete Grem2 gene deletion impacted mouse survival and body growth. Partial Grem2 inactivation in Grem2+/- female mice led to increased trabecular BMD of femur and increased trabecular bone mass in tibia due to increased trabecular thickness, with an unchanged cortical thickness, as compared with wildtype littermates. Furthermore, Grem2 inactivation stimulated osteoblast differentiation, as evidenced by higher alkaline phosphatase (Alp), osteocalcin (Bglap), and osterix (Sp7) mRNA expression after BMP-2 stimulation in calvarial osteoblasts and osteoblasts from the long bones of Grem2-/- mice compared to wildtype littermates. These findings suggest that GREM2 is a possible target for novel osteoporotic treatments, to increase trabecular bone mass and prevent osteoporotic fractures.
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Affiliation(s)
- Karin H Nilsson
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Osteoporosis Centre, Centre for Bone and Arthritis Research at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
| | - Petra Henning
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Osteoporosis Centre, Centre for Bone and Arthritis Research at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jianyao Wu
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Osteoporosis Centre, Centre for Bone and Arthritis Research at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Klara Sjögren
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Osteoporosis Centre, Centre for Bone and Arthritis Research at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ulf H Lerner
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Osteoporosis Centre, Centre for Bone and Arthritis Research at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Claes Ohlsson
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Osteoporosis Centre, Centre for Bone and Arthritis Research at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Drug Treatment, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Sofia Movérare-Skrtic
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Osteoporosis Centre, Centre for Bone and Arthritis Research at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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2
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Ahmad FS, Jin Y, Grassam-Rowe A, Zhou Y, Yuan M, Fan X, Zhou R, Mu-u-min R, O'Shea C, Ibrahim AM, Hyder W, Aguib Y, Yacoub M, Pavlovic D, Zhang Y, Tan X, Lei M, Terrar DA. Generation of cardiomyocytes from human-induced pluripotent stem cells resembling atrial cells with ability to respond to adrenoceptor agonists. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220312. [PMID: 37122218 PMCID: PMC10150206 DOI: 10.1098/rstb.2022.0312] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 12/07/2022] [Indexed: 05/02/2023] Open
Abstract
Atrial fibrillation (AF) is the most common chronic arrhythmia presenting a heavy disease burden. We report a new approach for generating cardiomyocytes (CMs) resembling atrial cells from human-induced pluripotent stem cells (hiPSCs) using a combination of Gremlin 2 and retinoic acid treatment. More than 40% of myocytes showed rod-shaped morphology, expression of CM proteins (including ryanodine receptor 2, α-actinin-2 and F-actin) and striated appearance, all of which were broadly similar to the characteristics of adult atrial myocytes (AMs). Isolated myocytes were electrically quiescent until stimulated to fire action potentials with an AM profile and an amplitude of approximately 100 mV, arising from a resting potential of approximately -70 mV. Single-cell RNA sequence analysis showed a high level of expression of several atrial-specific transcripts including NPPA, MYL7, HOXA3, SLN, KCNJ4, KCNJ5 and KCNA5. Amplitudes of calcium transients recorded from spontaneously beating cultures were increased by the stimulation of α-adrenoceptors (activated by phenylephrine and blocked by prazosin) or β-adrenoceptors (activated by isoproterenol and blocked by CGP20712A). Our new approach provides human AMs with mature characteristics from hiPSCs which will facilitate drug discovery by enabling the study of human atrial cell signalling pathways and AF. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- Faizzan S. Ahmad
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
- Cure8bio, Inc, 395 Fulton Street, Westbury, NY 11590, USA
| | - Yongcheng Jin
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | | | - Yafei Zhou
- Key Laboratory of Medical Electrophysiology of the Ministry of Education and Institute of Cardiovascular Research, Southwest Medical University, Luzhou 6400, People's Republic of China
- Shaanxi Institute for Pediatric Diseases, Department of Cardiology, Xi'an Children's Hospital, Xi'an 710003, People's Republic of China
| | - Meng Yuan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA
| | - Xuehui Fan
- Key Laboratory of Medical Electrophysiology of the Ministry of Education and Institute of Cardiovascular Research, Southwest Medical University, Luzhou 6400, People's Republic of China
| | - Rui Zhou
- Key Laboratory of Medical Electrophysiology of the Ministry of Education and Institute of Cardiovascular Research, Southwest Medical University, Luzhou 6400, People's Republic of China
| | - Razik Mu-u-min
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Christopher O'Shea
- Institute of Cardiovascular Sciences, College of Medicine and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Ayman M. Ibrahim
- Aswan Heart Centre, Aswan 1242770, Egypt
- Department of Zoology, Faculty of Science, Cairo University, Cairo 12613, Egypt
| | - Wajiha Hyder
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Yasmine Aguib
- Aswan Heart Centre, Aswan 1242770, Egypt
- National Heart and Lung Institute, Heart Science Centre, Imperial College London, Middlesex SW3 6LY, UK
| | - Magdi Yacoub
- Aswan Heart Centre, Aswan 1242770, Egypt
- National Heart and Lung Institute, Heart Science Centre, Imperial College London, Middlesex SW3 6LY, UK
| | - Davor Pavlovic
- Institute of Cardiovascular Sciences, College of Medicine and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Yanmin Zhang
- Shaanxi Institute for Pediatric Diseases, Department of Cardiology, Xi'an Children's Hospital, Xi'an 710003, People's Republic of China
| | - Xiaoqiu Tan
- Key Laboratory of Medical Electrophysiology of the Ministry of Education and Institute of Cardiovascular Research, Southwest Medical University, Luzhou 6400, People's Republic of China
| | - Ming Lei
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Derek A. Terrar
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
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3
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Luderman LN, Michaels MT, Levic DS, Knapik EW. Zebrafish Erc1b mediates motor innervation and organization of craniofacial muscles in control of jaw movement. Dev Dyn 2023; 252:104-123. [PMID: 35708710 DOI: 10.1002/dvdy.511] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/31/2022] [Accepted: 06/03/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Movement of the lower jaw, a common behavior observed among vertebrates, is required for eating and processing food. This movement is controlled by signals sent from the trigeminal motor nerve through neuromuscular junctions (NMJs) to the masticatory muscles. Dysfunctional jaw movements contribute to craniomandibular disorders, yet the pathophysiology of these disorders is not well understood, as limited studies have been conducted on the molecular mechanisms of jaw movement. RESULTS Using erc1b/kimm533 genetic loss of function mutant, we evaluated lower jaw muscle organization and innervation by the cranial motor nerves in developing zebrafish. Using time-lapse confocal imaging of the erc1b mutant in a transgenic fluorescent reporter line, we found delayed trigeminal nerve growth and disrupted nerve branching architecture during muscle innervation. By automated 3D image analysis of NMJ distribution, we identified an increased number of small, disorganized NMJ clusters in erc1b mutant larvae compared to WT siblings. Using genetic replacement experiments, we determined the Rab GTPase binding domain of Erc1b is required for cranial motor nerve branching, but not NMJ organization or muscle attachment. CONCLUSIONS We identified Erc1b/ERC1 as a novel component of a genetic pathway contributing to muscle organization, trigeminal nerve outgrowth, and NMJ spatial distribution during development that is required for jaw movement.
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Affiliation(s)
- Lauryn N Luderman
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Mackenzie T Michaels
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Daniel S Levic
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
- Neuroscience Graduate Program, Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
| | - Ela W Knapik
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
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Zhou X, Xu W, Wang Y, Zhang H, Zhang L, Li C, Yao S, Huang Z, Huang L, Luo D. LncRNA DNM3OS regulates GREM2 via miR-127-5p to suppress early chondrogenic differentiation of rat mesenchymal stem cells under hypoxic conditions. Cell Mol Biol Lett 2021; 26:22. [PMID: 34049478 PMCID: PMC8161583 DOI: 10.1186/s11658-021-00269-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 05/20/2021] [Indexed: 12/13/2022] Open
Abstract
Background Improved chondrogenic differentiation of mesenchymal stem cells (MSCs) by genetic regulation is a potential method for regenerating articular cartilage. MiR-127-5p has been reported to promote cartilage differentiation of rat bone marrow MSCs (rMSCs); however, the regulatory mechanisms underlying hypoxia-stimulated chondrogenic differentiation remain unknown. Methods rMSCs were induced to undergo chondrogenic differentiation under normoxic or hypoxic conditions. Expression of lncRNA DNM3OS, miR-127-5p, and GREM2 was detected by quantitative real-time PCR. Proteoglycans were detected by Alcian blue staining. Western blot assays were performed to examine the relative levels of GREM2 and chondrogenic differentiation related proteins. Luciferase reporter assays were performed to assess the association among DNM3OS, miR-127-5p, and GREM2. Results MiR-127-5p levels were upregulated, while DNM3OS and GREM2 levels were downregulated in rMSCs induced to undergo chondrogenic differentiation, and those changes were attenuated by hypoxic conditions (1% O2). Further in vitro experiments revealed that downregulation of miR-127-5p reduced the production of proteoglycans and expression of chondrogenic differentiation markers (COL1A1, COL2A1, SOX9, and ACAN) and osteo/chondrogenic markers (BMP-2, p-SMAD1/2). MiR-127-5p overexpression produced the opposite results in rMSCs induced to undergo chondrogenic differentiation under hypoxic conditions. GREM2 was found to be a direct target of miR-127-5p, which was suppressed in rMSCs undergoing chondrogenic differentiation. Moreover, DNM3OS could directly bind to miR-127-5p and inhibit chondrogenic differentiation of rMSCs via regulating GREM2. Conclusions Our study revealed a novel molecular pathway (DNM3OS/miR-127-5p/GREM2) that may be involved in hypoxic chondrogenic differentiation.
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Affiliation(s)
- Xiaozhong Zhou
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China.,The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Wangyang Xu
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China
| | - Yeyang Wang
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China
| | - Hui Zhang
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China
| | - Li Zhang
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China
| | - Chao Li
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China
| | - Shun Yao
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China
| | - Zixiang Huang
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China
| | - Lishan Huang
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China
| | - Dixin Luo
- The Spine Department, Orthopaedic Center, Guangdong Second Provincial General Hospital, No. 466, Xingangzhong Road, Haizhu District, Guangzhou, 510317, Guangdong, People's Republic of China.
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5
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Abstract
PURPOSE OF REVIEW Atrial fibrillation is the most common sustained cardiac arrhythmia. In addition to traditional risk factors, it is increasingly recognized that a genetic component underlies atrial fibrillation development. This review aims to provide an overview of the genetic cause of atrial fibrillation and clinical applications, with a focus on recent developments. RECENT FINDINGS Genome-wide association studies have now identified around 140 genetic loci associated with atrial fibrillation. Studies into the effects of several loci and their tentative gene targets have identified novel pathways associated with atrial fibrillation development. However, further validations of causality are still needed for many implicated genes. Genetic variants at identified loci also help predict individual atrial fibrillation risk and response to different therapies. SUMMARY Continued advances in the field of genetics and molecular biology have led to significant insight into the genetic underpinnings of atrial fibrillation. Potential clinical applications of these studies include the identification of new therapeutic targets and development of genetic risk scores to optimize management of this common cardiac arrhythmia.
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Affiliation(s)
- Jitae A. Kim
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Mihail G. Chelu
- Department of Cardiology, Baylor College of Medicine, Houston, TX, USA
| | - Na Li
- Department of Medicine (Section of Cardiovascular Research), Baylor College of Medicine, Houston, TX
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX
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6
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Atrial fibrillation-a complex polygenetic disease. Eur J Hum Genet 2020; 29:1051-1060. [PMID: 33279945 PMCID: PMC8298566 DOI: 10.1038/s41431-020-00784-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 10/27/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common type of arrhythmia. Epidemiological studies have documented a substantial genetic component. More than 160 genes have been associated with AF during the last decades. Some of these were discovered by classical linkage studies while the majority relies on functional studies or genome-wide association studies. In this review, we will evaluate the genetic basis of AF and the role of both common and rare genetic variants in AF. Rare variants in multiple ion-channel genes as well as gap junction and transcription factor genes have been associated with AF. More recently, a growing body of evidence has implicated structural genes with AF. An increased burden of atrial fibrosis in AF patients compared with non-AF patients has also been reported. These findings challenge our traditional understanding of AF being an electrical disease. We will focus on several quantitative landmark papers, which are transforming our understanding of AF by implicating atrial cardiomyopathies in the pathogenesis. This new AF research field may enable better diagnostics and treatment in the future.
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7
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Genetics and Epigenetics of Atrial Fibrillation. Int J Mol Sci 2020; 21:ijms21165717. [PMID: 32784971 PMCID: PMC7460853 DOI: 10.3390/ijms21165717] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/22/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022] Open
Abstract
Atrial fibrillation (AF) is known to be the most common supraventricular arrhythmia affecting up to 1% of the general population. Its prevalence exponentially increases with age and could reach up to 8% in the elderly population. The management of AF is a complex issue that is addressed by extensive ongoing basic and clinical research. AF centers around different types of disturbances, including ion channel dysfunction, Ca2+-handling abnormalities, and structural remodeling. Genome-wide association studies (GWAS) have uncovered over 100 genetic loci associated with AF. Most of these loci point to ion channels, distinct cardiac-enriched transcription factors, as well as to other regulatory genes. Recently, the discovery of post-transcriptional regulatory mechanisms, involving non-coding RNAs (especially microRNAs), DNA methylation, and histone modification, has allowed to decipher how a normal heart develops and which modifications are involved in reshaping the processes leading to arrhythmias. This review aims to provide a current state of the field regarding the identification and functional characterization of AF-related epigenetic regulatory networks
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8
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Ragab AAY, Sitorus GDS, Brundel BBJJM, de Groot NMS. The Genetic Puzzle of Familial Atrial Fibrillation. Front Cardiovasc Med 2020; 7:14. [PMID: 32118049 PMCID: PMC7033574 DOI: 10.3389/fcvm.2020.00014] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/28/2020] [Indexed: 12/17/2022] Open
Abstract
Atrial fibrillation (AF) is the most common clinical tachyarrhythmia. In Europe, AF is expected to reach a prevalence of 18 million by 2060. This estimate will increase hospitalization for AF to 4 million and 120 million outpatient visits. Besides being an independent risk factor for mortality, AF is also associated with an increased risk of morbidities. Although there are many well-defined risk factors for developing AF, no identifiable risk factors or cardiac pathology is seen in up to 30% of the cases. The heritability of AF has been investigated in depth since the first report of familial atrial fibrillation (FAF) in 1936. Despite the limited value of animal models, the advances in molecular genetics enabled identification of many common and rare variants related to FAF. The importance of AF heritability originates from the high prevalence of lone AF and the lack of clear understanding of the underlying pathophysiology. A better understanding of FAF will facilitate early identification of people at high risk of developing FAF and subsequent development of more effective management options. In this review, we reviewed FAF epidemiological studies, identified common and rare variants, and discussed their clinical implications and contributions to developing new personalized therapeutic strategies.
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Affiliation(s)
- Ahmed A Y Ragab
- Department of Cardiology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Gustaf D S Sitorus
- Department of Cardiology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Bianca B J J M Brundel
- Department of Physiology, Institute for Cardiovascular Research, VU Medical Center, Amsterdam, Netherlands
| | - Natasja M S de Groot
- Department of Cardiology, Erasmus University Medical Center, Rotterdam, Netherlands
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9
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Abstract
Background Atrial fibrillation (AF) is a common arrhythmia seen in clinical practice. Occasionally, no common risk factors are present in patients with this arrhythmia. This suggests the potential underlying role of genetic factors associated with predisposition to developing AF. Methods and Results We conducted a comprehensive review of the literature through large online libraries, including PubMed. Many different potassium and sodium channel mutations have been discussed in their relation to AF. There have also been non–ion channel mutations that have been linked to AF. Genome‐wide association studies have helped in identifying potential links between single‐nucleotide polymorphisms and AF. Ancestry studies have also highlighted a role of genetics in AF. Blacks with a higher percentage of European ancestry are at higher risk of developing AF. The emerging field of ablatogenomics involves the use of genetic profiles in their relation to recurrence of AF after catheter ablation. Conclusions The evidence for the underlying role of genetics in AF continues to expand. Ultimately, the role of genetics in risk stratification of AF and its recurrence is of significant interest. No established risk scores that are useful in clinical practice are present to date.
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Affiliation(s)
- Julien Feghaly
- 1 Department of Internal Medicine St Louis University Hospital St Louis MO
| | - Patrick Zakka
- 2 Department of Internal Medicine Emory University Hospital Atlanta GA
| | - Barry London
- 3 Department of Cardiovascular Medicine University of Iowa Carver College of Medicine Iowa City IA
| | - Calum A MacRae
- 4 Department of Cardiovascular Medicine Brigham and Women's Hospital Boston MA
| | - Marwan M Refaat
- 5 Department of Cardiovascular Medicine American University of Beirut Medical Center Beirut Lebanon
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10
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Kawagishi-Hotta M, Hasegawa S, Igarashi T, Date Y, Ishii Y, Inoue Y, Hasebe Y, Yamada T, Arima M, Iwata Y, Kobayashi T, Nakata S, Sugiura K, Akamatsu H. Increase of gremlin 2 with age in human adipose-derived stromal/stem cells and its inhibitory effect on adipogenesis. Regen Ther 2019; 11:324-330. [PMID: 31709279 PMCID: PMC6831850 DOI: 10.1016/j.reth.2019.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/23/2019] [Accepted: 09/20/2019] [Indexed: 02/07/2023] Open
Abstract
Introduction Adipose-derived stromal/stem cells (ASCs) have attracted attention as a promising material for regenerative medicine. Previously, we reported an age-related decrease in the adipogenic potential of ASCs from human subjects and found that the individual difference in this potential increased with age, although the mechanisms remain unclear. Recently, other groups demonstrated that a secreted antagonist of bone morphogenetic protein (BMP) signaling, Gremlin 2 (GREM2), inhibits the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) into osteoblasts and the adipogenesis of 3T3-L1 cell. Here, we examined the effects of GREM2 on the differentiation of ASCs into adipocytes. Methods To examine changes in GREM2 expression levels with age, immunohistochemistry was performed on subcutaneous adipose tissues from subjects 12–97 years of age. Next, GREM2 gene expression levels in ASCs collected from subjects 5–90 years of age were examined by RT-PCR, and the change with age and correlation between the expression level and the adipogenic potential of ASCs were analyzed. In addition, to assess whether GREM2 affects adipogenesis, ASCs (purchased from a vendor) were cultured to induce adipogenesis with recombinant GREM2 protein, and siRNA-induced GREM2 knockdown experiment was also performed using aged ASCs. Results In adipose tissues, GREM2 expression was observed in cells, including ASCs, but not in mature adipocytes, and the expression level per cell increased with age. GREM2 expression levels in ASCs cultured in vitro also increased with age, and the individual differences in the level increased with age. Of note, partial correlation analysis controlled for age revealed that the adipogenic potential of ASCs and the GREM2 gene expression level were negatively correlated. Furthermore, based on a GREM2 addition experiment, GREM2 has inhibitory effects on the adipogenesis of ASCs through activation of Wnt/β-catenin signaling. On the other hand, GREM2 knockdown in aged ASCs promoted adipogenesis. Conclusions The GREM2 expression level was confirmed to play a role in the age-related decrease in adipogenic potential observed in ASCs isolated from adipose tissues as well as in the enhancement of the individual difference, which increased with age. GREM2 in adipose tissues increased with age, which suggested that GREM2 functions as an inhibitory factor of adipogenesis in ASCs. GREM2 in human adipose tissues increase with age. GREM2 expression in adipose-derived stromal/stem cells (ASCs) increased with age. In ASCs, adipogenic potential and GREM2 expression showed a negative correlation. Recombinant GREM2 inhibited the adipogenesis of ASCs. GREM2 knockdown in aged ASCs restored adipogenesis.
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Affiliation(s)
- Mika Kawagishi-Hotta
- Research Laboratories, Nippon Menard Cosmetic Co., Ltd, Japan.,Nagoya University-MENARD Collaborative Research Chair, Nagoya University Graduate School of Medicine, Japan.,Department of Applied Cell and Regenerative Medicine, Fujita Health University School of Medicine, Japan
| | - Seiji Hasegawa
- Research Laboratories, Nippon Menard Cosmetic Co., Ltd, Japan.,Nagoya University-MENARD Collaborative Research Chair, Nagoya University Graduate School of Medicine, Japan.,Department of Dermatology, Fujita Health University School of Medicine, Japan
| | - Toshio Igarashi
- Research Laboratories, Nippon Menard Cosmetic Co., Ltd, Japan
| | - Yasushi Date
- Research Laboratories, Nippon Menard Cosmetic Co., Ltd, Japan.,Nagoya University-MENARD Collaborative Research Chair, Nagoya University Graduate School of Medicine, Japan
| | - Yoshie Ishii
- Research Laboratories, Nippon Menard Cosmetic Co., Ltd, Japan.,Department of Applied Cell and Regenerative Medicine, Fujita Health University School of Medicine, Japan
| | - Yu Inoue
- Research Laboratories, Nippon Menard Cosmetic Co., Ltd, Japan.,Nagoya University-MENARD Collaborative Research Chair, Nagoya University Graduate School of Medicine, Japan
| | - Yuichi Hasebe
- Research Laboratories, Nippon Menard Cosmetic Co., Ltd, Japan.,Nagoya University-MENARD Collaborative Research Chair, Nagoya University Graduate School of Medicine, Japan
| | - Takaaki Yamada
- Research Laboratories, Nippon Menard Cosmetic Co., Ltd, Japan.,Department of Applied Cell and Regenerative Medicine, Fujita Health University School of Medicine, Japan.,Department of Dermatology, Fujita Health University School of Medicine, Japan
| | - Masaru Arima
- Department of Dermatology, Fujita Health University School of Medicine, Japan
| | - Yohei Iwata
- Department of Dermatology, Fujita Health University School of Medicine, Japan
| | - Tsukane Kobayashi
- Department of Dermatology, Fujita Health University School of Medicine, Japan
| | - Satoru Nakata
- Research Laboratories, Nippon Menard Cosmetic Co., Ltd, Japan
| | - Kazumitsu Sugiura
- Department of Dermatology, Fujita Health University School of Medicine, Japan
| | - Hirohiko Akamatsu
- Department of Applied Cell and Regenerative Medicine, Fujita Health University School of Medicine, Japan
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11
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Abstract
In the decade since Disease Models & Mechanisms was launched, the emergence of Big Data as the main foundation of biological information is having a profound effect on how we do research and it has provoked some interesting questions. Is Big Data exploration replacing hypothesis-driven basic research? And, to what extent is disease modeling in the laboratory still relevant to medical research? Recent examples of synergistic approaches utilizing animal modeling and electronic medical records mining show that combining efforts between disease models and clinical datasets can uncover not only disease etiologies, but also novel molecular and cellular mechanisms linked to gene function. Summary: This Editorial reflects on how the emergence of Big Data has affected traditional disease modeling over the past decade, and on DMM's place in this changing landscape.
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Affiliation(s)
- Antonis K Hatzopoulos
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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12
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Viaene AN, Zhang B, Martinez-Lage M, Xiang C, Tosi U, Thawani JP, Gungor B, Zhu Y, Roccograndi L, Zhang L, Bailey RL, Storm PB, O’Rourke DM, Resnick AC, Grady MS, Dahmane N. Transcriptome signatures associated with meningioma progression. Acta Neuropathol Commun 2019; 7:67. [PMID: 31039818 PMCID: PMC6489307 DOI: 10.1186/s40478-019-0690-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 02/25/2019] [Indexed: 12/12/2022] Open
Abstract
Meningiomas are the most common primary brain tumor of adults. The majority are benign (WHO grade I), with a mostly indolent course; 20% of them (WHO grade II and III) are, however, considered aggressive and require a more complex management. WHO grade II and III tumors are heterogeneous and, in some cases, can develop from a prior lower grade meningioma, although most arise de novo. Mechanisms leading to progression or implicated in de novo grade II and III tumorigenesis are poorly understood. RNA-seq was used to profile the transcriptome of grade I, II, and III meningiomas and to identify genes that may be involved in progression. Bioinformatic analyses showed that grade I meningiomas that progress to a higher grade are molecularly different from those that do not. As such, we identify GREM2, a regulator of the BMP pathway, and the snoRNAs SNORA46 and SNORA48, as being significantly reduced in meningioma progression. Additionally, our study has identified several novel fusion transcripts that are differentially present in meningiomas, with grade I tumors that did not progress presenting more fusion transcripts than all other tumors. Interestingly, our study also points to a difference in the tumor immune microenvironment that correlates with histopathological grade.
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Abstract
IMPACT STATEMENT By compiling findings from recent studies, this review will garner novel insight on the dynamic and complex role of BMP signaling in diseases of inflammation, highlighting the specific roles played by both individual ligands and endogenous antagonists. Ultimately, this summary will help inform the high therapeutic value of targeting this pathway for modulating diseases of inflammation.
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Affiliation(s)
- David H Wu
- Division of Cardiovascular Medicine, Department of
Medicine and Department of Cell & Developmental Biology, Vanderbilt
University Medical Center, Nashville, TN 37232, USA
| | - Antonis K Hatzopoulos
- Division of Cardiovascular Medicine, Department of
Medicine and Department of Cell & Developmental Biology, Vanderbilt
University Medical Center, Nashville, TN 37232, USA
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14
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Abstract
PURPOSE OF REVIEW To describe recent findings regarding the role of rare and common genetic variants in atrial fibrillation. RECENT FINDINGS Atrial fibrillation is associated with several clinical risk factors and its development is affected by genetic background. To date, rare variants from more than 30 genes have been identified from studies of familial cases or individuals with lone atrial fibrillation. In addition to using the candidate gene approach for the identification of rare variants, next-generation sequencing approaches such as genomic, whole exome and targeted sequencing have been employed. Furthermore, evidence of association between common variants and atrial fibrillation has been discovered through genome-wide association studies. Although the power of any one single-nucleotide polymorphism (SNP) associated with atrial fibrillation is weak, a genetic risk score comprising 12 SNPs may identify individuals at an increased risk for atrial fibrillation. This SNP panel may also delineate genotypes to enable stratification of atrial fibrillation ablation therapy or periinterventional management. SUMMARY Although studies have demonstrated that atrial fibrillation is highly heritable, many aspects of atrial fibrillation remain unknown. Rigorous research efforts continue with the expectation that the contribution of variants and candidate genes that contribute to the overall genetic architecture of atrial fibrillation will be identified and characterized in the coming years.
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16
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Mostowska A, Biedziak B, Zadurska M, Bogdanowicz A, Olszewska A, Cieślińska K, Firlej E, Jagodziński PP. GREM2
nucleotide variants and the risk of tooth agenesis. Oral Dis 2017; 24:591-599. [DOI: 10.1111/odi.12793] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/07/2017] [Accepted: 10/03/2017] [Indexed: 12/17/2022]
Affiliation(s)
- A Mostowska
- Department of Biochemistry and Molecular Biology; Poznan University of Medical Sciences; Poznan Poland
| | - B Biedziak
- Division of Facial Malformation; Department of Dental Surgery; Poznan University of Medical Sciences; Poznan Poland
| | - M Zadurska
- Department of Orthodontics; Medical University of Warsaw; Warsaw Poland
| | - A Bogdanowicz
- Orthodoctic Clinic; Poznan University Hospital of Dentistry and Specialty Medicine; Poznan Poland
| | - A Olszewska
- Division of Facial Malformation; Department of Dental Surgery; Poznan University of Medical Sciences; Poznan Poland
| | - K Cieślińska
- Division of Facial Malformation; Department of Dental Surgery; Poznan University of Medical Sciences; Poznan Poland
| | - E Firlej
- Division of Facial Malformation; Department of Dental Surgery; Poznan University of Medical Sciences; Poznan Poland
| | - PP Jagodziński
- Department of Biochemistry and Molecular Biology; Poznan University of Medical Sciences; Poznan Poland
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17
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Bylund JB, Trinh LT, Awgulewitsch CP, Paik DT, Jetter C, Jha R, Zhang J, Nolan K, Xu C, Thompson TB, Kamp TJ, Hatzopoulos AK. Coordinated Proliferation and Differentiation of Human-Induced Pluripotent Stem Cell-Derived Cardiac Progenitor Cells Depend on Bone Morphogenetic Protein Signaling Regulation by GREMLIN 2. Stem Cells Dev 2017; 26:678-693. [PMID: 28125926 DOI: 10.1089/scd.2016.0226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Heart development depends on coordinated proliferation and differentiation of cardiac progenitor cells (CPCs), but how the two processes are synchronized is not well understood. Here, we show that the secreted Bone Morphogenetic Protein (BMP) antagonist GREMLIN 2 (GREM2) is induced in CPCs shortly after cardiac mesoderm specification during differentiation of human pluripotent stem cells. GREM2 expression follows cardiac lineage differentiation independently of the differentiation method used, or the origin of the pluripotent stem cells, suggesting that GREM2 is linked to cardiogenesis. Addition of GREM2 protein strongly increases cardiomyocyte output compared to established procardiogenic differentiation methods. Our data show that inhibition of canonical BMP signaling by GREM2 is necessary to promote proliferation of CPCs. However, canonical BMP signaling inhibition alone is not sufficient to induce cardiac differentiation, which depends on subsequent JNK pathway activation specifically by GREM2. These findings may have broader implications in the design of approaches to orchestrate growth and differentiation of pluripotent stem cell-derived lineages that depend on precise regulation of BMP signaling.
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Affiliation(s)
- Jeffery B Bylund
- 1 Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center , Nashville, Tennessee.,2 Department of Pharmacology, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Linh T Trinh
- 1 Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center , Nashville, Tennessee
| | - Cassandra P Awgulewitsch
- 1 Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center , Nashville, Tennessee
| | - David T Paik
- 1 Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center , Nashville, Tennessee.,3 Department of Cell and Developmental Biology, Vanderbilt University School of Medicine , Nashville, Tennessee
| | - Christopher Jetter
- 1 Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center , Nashville, Tennessee
| | - Rajneesh Jha
- 4 Department of Pediatrics, Emory University School of Medicine , Atlanta, Georgia
| | - Jianhua Zhang
- 5 Stem Cell and Regenerative Medicine Center, University of Wisconsin School of Medicine and Public Health , Madison, Wisconsin
| | - Kristof Nolan
- 6 Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati , Cincinnati, Ohio
| | - Chunhui Xu
- 4 Department of Pediatrics, Emory University School of Medicine , Atlanta, Georgia
| | - Thomas B Thompson
- 6 Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati , Cincinnati, Ohio
| | - Timothy J Kamp
- 5 Stem Cell and Regenerative Medicine Center, University of Wisconsin School of Medicine and Public Health , Madison, Wisconsin
| | - Antonis K Hatzopoulos
- 1 Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center , Nashville, Tennessee.,3 Department of Cell and Developmental Biology, Vanderbilt University School of Medicine , Nashville, Tennessee
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18
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The Role of Pharmacogenetics in Atrial Fibrillation Therapeutics: Is Personalized Therapy in Sight? J Cardiovasc Pharmacol 2016; 67:9-18. [PMID: 25970841 DOI: 10.1097/fjc.0000000000000280] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia worldwide requiring therapy. Despite recent advances in catheter-based and surgical therapy, antiarrhythmic drugs (AADs) remain the mainstay of treatment for symptomatic AF. However, response in individual patients is highly variable with over half the patients treated with rhythm control therapy experiencing recurrence of AF within a year. Contemporary AADs used to suppress AF are incompletely and unpredictably effective and associated with significant risks of proarrhythmia and noncardiac toxicities. Furthermore, this "one-size" fits all strategy for selecting antiarrhythmics is based largely on minimizing risk of adverse effects rather than on the likelihood of suppressing AF. The limited success of rhythm control therapy is in part due to heterogeneity of the underlying substrate, interindividual differences in disease mechanisms, and our inability to predict response to AADs in individual patients. Genetic studies of AF over the past decade have revealed that susceptibility to and response to therapy for AF is modulated by the underlying genetic substrate. However, the bedside application of these new discoveries to the management of AF patients has thus far been disappointing. This may in part be related to our limited understanding about genetic predictors of drug response in general, the challenges associated with determining efficacy of response to AADs, and lack of randomized genotype-directed clinical trials. Nonetheless, recent studies have shown that common AF susceptibility risk alleles at the chromosome 4q25 locus modulated response to AADs, electrical cardioversion, and ablation therapy. This monograph discusses how genetic approaches to AF have not only provided important insights into underlying mechanisms but also identified AF subtypes that can be better targeted with more mechanism-based "personalized" therapy.
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19
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Nolan K, Kattamuri C, Rankin SA, Read RJ, Zorn AM, Thompson TB. Structure of Gremlin-2 in Complex with GDF5 Gives Insight into DAN-Family-Mediated BMP Antagonism. Cell Rep 2016; 16:2077-2086. [PMID: 27524626 PMCID: PMC5001929 DOI: 10.1016/j.celrep.2016.07.046] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 07/07/2016] [Accepted: 07/15/2016] [Indexed: 11/20/2022] Open
Abstract
The DAN family, including Gremlin-1 and Gremlin-2 (Grem1 and Grem2), represents a large family of secreted BMP (bone morphogenetic protein) antagonists. However, how DAN proteins specifically inhibit BMP signaling has remained elusive. Here, we report the structure of Grem2 bound to GDF5 at 2.9-Å resolution. The structure reveals two Grem2 dimers binding perpendicularly to each GDF5 monomer, resembling an H-like structure. Comparison to the unbound Grem2 structure reveals a dynamic N terminus that undergoes significant transition upon complex formation, leading to simultaneous interaction with the type I and type II receptor motifs on GDF5. Binding studies show that DAN-family members can interact with BMP-type I receptor complexes, whereas Noggin outcompetes the type I receptor for ligand binding. Interestingly, Grem2-GDF5 forms a stable aggregate-like structure in vitro that is not clearly observed for other antagonists, including Noggin and Follistatin. These findings exemplify the structural and functional diversity across the various BMP antagonist families.
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Affiliation(s)
- Kristof Nolan
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Chandramohan Kattamuri
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Scott A Rankin
- Perinatal Institute, Cincinnati Children's Research Foundation, and Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Randy J Read
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England
| | - Aaron M Zorn
- Perinatal Institute, Cincinnati Children's Research Foundation, and Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Thomas B Thompson
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH 45267, USA.
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20
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Sanders LN, Schoenhard JA, Saleh MA, Mukherjee A, Ryzhov S, McMaster WG, Nolan K, Gumina RJ, Thompson TB, Magnuson MA, Harrison DG, Hatzopoulos AK. BMP Antagonist Gremlin 2 Limits Inflammation After Myocardial Infarction. Circ Res 2016; 119:434-49. [PMID: 27283840 DOI: 10.1161/circresaha.116.308700] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/09/2016] [Indexed: 11/16/2022]
Abstract
RATIONALE We have recently shown that the bone morphogenetic protein (BMP) antagonist Gremlin 2 (Grem2) is required for early cardiac development and cardiomyocyte differentiation. Our initial studies discovered that Grem2 is strongly induced in the adult heart after experimental myocardial infarction (MI). However, the function of Grem2 and BMP-signaling inhibitors after cardiac injury is currently unknown. OBJECTIVE To investigate the role of Grem2 during cardiac repair and assess its potential to improve ventricular function after injury. METHODS AND RESULTS Our data show that Grem2 is transiently induced after MI in peri-infarct area cardiomyocytes during the inflammatory phase of cardiac tissue repair. By engineering loss- (Grem2(-/-)) and gain- (TG(Grem2)) of-Grem2-function mice, we discovered that Grem2 controls the magnitude of the inflammatory response and limits infiltration of inflammatory cells in peri-infarct ventricular tissue, improving cardiac function. Excessive inflammation in Grem2(-/-) mice after MI was because of overactivation of canonical BMP signaling, as proven by the rescue of the inflammatory phenotype through administration of the canonical BMP inhibitor, DMH1. Furthermore, intraperitoneal administration of Grem2 protein in wild-type mice was sufficient to reduce inflammation after MI. Cellular analyses showed that BMP2 acts with TNFα to induce expression of proinflammatory proteins in endothelial cells and promote adhesion of leukocytes, whereas Grem2 specifically inhibits the BMP2 effect. CONCLUSIONS Our results indicate that Grem2 provides a molecular barrier that controls the magnitude and extent of inflammatory cell infiltration by suppressing canonical BMP signaling, thereby providing a novel mechanism for limiting the adverse effects of excessive inflammation after MI.
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Affiliation(s)
- Lehanna N Sanders
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - John A Schoenhard
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - Mohamed A Saleh
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - Amrita Mukherjee
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - Sergey Ryzhov
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - William G McMaster
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - Kristof Nolan
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - Richard J Gumina
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - Thomas B Thompson
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - Mark A Magnuson
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - David G Harrison
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.)
| | - Antonis K Hatzopoulos
- From the Division of Cardiovascular Medicine, Department of Medicine (L.N.S., J.A.S., A.M., R.J.G., A.K.H.), Department of Cell and Developmental Biology (L.N.S., A.K.H.), Division of Clinical Pharmacology, Department of Medicine (M.A.S., W.G.M., D.G.H.), and Division of General Surgery, Department of Surgery (W.G.M.), Vanderbilt University Medical Center, Nashville, TN; Maine Medical Center Research Institute, Scarborough (S.R.); Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, OH (K.N., T.B.T.); CentraCare Health, St. Cloud, MN (J.A.S.); Cincinnati Children's Hospital Medical Center, OH (A.M.); Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt (M.A.S.); and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN (M.A.M.).
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21
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Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia despite substantial efforts to understand the pathophysiology of the condition and develop improved treatments. Identifying the underlying causative mechanisms of AF in individual patients is difficult and the efficacy of current therapies is suboptimal. Consequently, the incidence of AF is steadily rising and there is a pressing need for novel therapies. Research has revealed that defects in specific molecular pathways underlie AF pathogenesis, resulting in electrical conduction disorders that drive AF. The severity of this so-called electropathology correlates with the stage of AF disease progression and determines the response to AF treatment. Therefore, unravelling the molecular mechanisms underlying electropathology is expected to fuel the development of innovative personalized diagnostic tools and mechanism-based therapies. Moreover, the co-creation of AF studies with patients to implement novel diagnostic tools and therapies is a prerequisite for successful personalized AF management. Currently, various treatment modalities targeting AF-related electropathology, including lifestyle changes, pharmaceutical and nutraceutical therapy, substrate-based ablative therapy, and neuromodulation, are available to maintain sinus rhythm and might offer a novel holistic strategy to treat AF.
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Affiliation(s)
- Bianca J. J. M. Brundel
- Department of Physiology, Amsterdam University Medical Centers, VU Universiteit, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,
| | - Xun Ai
- Department of Physiology and Cell Biology, College of Medicine/Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | | | - Myrthe F. Kuipers
- AFIPonline.org, Atrial Fibrillation Innovation Platform, Amsterdam, Netherlands
| | - Gregory Y. H. Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK.,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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22
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Bylund JB, Hatzopoulos AK. Differentiation of Atrial Cardiomyocytes from Pluripotent Stem Cells Using the BMP Antagonist Grem2. J Vis Exp 2016:53919. [PMID: 27023256 PMCID: PMC4828231 DOI: 10.3791/53919] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Protocols for generating populations of cardiomyocytes from pluripotent stem cells have been developed, but these generally yield cells of mixed phenotypes. Researchers interested in pursuing studies involving specific myocyte subtypes require a more directed differentiation approach. By treating mouse embryonic stem (ES) cells with Grem2, a secreted BMP antagonist that is necessary for atrial chamber formation in vivo, a large number of cardiac cells with an atrial phenotype can be generated. Use of the engineered Myh6-DSRed-Nuc pluripotent stem cell line allows for identification, selection, and purification of cardiomyocytes. In this protocol embryoid bodies are generated from Myh6-DSRed-Nuc cells using the hanging drop method and kept in suspension until differentiation day 4 (d4). At d4 cells are treated with Grem2 and plated onto gelatin coated plates. Between d8-d10 large contracting areas are observed in the cultures and continue to expand and mature through d14. Molecular, histological and electrophysiogical analyses indicate cells in Grem2-treated cells acquire atrial-like characteristics providing an in vitro model to study the biology of atrial cardiomyocytes and their response to various pharmacological agents.
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Affiliation(s)
- Jeffery B Bylund
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University School of Medicine; Department of Pharmacology, Vanderbilt University
| | - Antonis K Hatzopoulos
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University School of Medicine; Department of Cell & Developmental Biology, Vanderbilt University School of Medicine;
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23
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Genome-wide screening identifies a KCNIP1 copy number variant as a genetic predictor for atrial fibrillation. Nat Commun 2016; 7:10190. [PMID: 26831368 PMCID: PMC4740744 DOI: 10.1038/ncomms10190] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 11/16/2015] [Indexed: 01/01/2023] Open
Abstract
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Previous genome-wide association studies had identified single-nucleotide polymorphisms in several genomic regions to be associated with AF. In human genome, copy number variations (CNVs) are known to contribute to disease susceptibility. Using a genome-wide multistage approach to identify AF susceptibility CNVs, we here show a common 4,470-bp diallelic CNV in the first intron of potassium interacting channel 1 gene (KCNIP1) is strongly associated with AF in Taiwanese populations (odds ratio=2.27 for insertion allele; P=6.23 × 10(-24)). KCNIP1 insertion is associated with higher KCNIP1 mRNA expression. KCNIP1-encoded protein potassium interacting channel 1 (KCHIP1) is physically associated with potassium Kv channels and modulates atrial transient outward current in cardiac myocytes. Overexpression of KCNIP1 results in inducible AF in zebrafish. In conclusions, a common CNV in KCNIP1 gene is a genetic predictor of AF risk possibly pointing to a functional pathway.
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Behnes M, Bertsch T, Weiss C, Ahmad-Nejad P, Akin I, Fastner C, El-Battrawy I, Lang S, Neumaier M, Borggrefe M, Hoffmann U. Triple head-to-head comparison of fibrotic biomarkers galectin-3, osteopontin and gremlin-1 for long-term prognosis in suspected and proven acute heart failure patients. Int J Cardiol 2016; 203:398-406. [DOI: 10.1016/j.ijcard.2015.10.127] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 08/18/2015] [Accepted: 10/18/2015] [Indexed: 01/14/2023]
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Durning SP, Flanagan-Steet H, Prasad N, Wells L. O-Linked β-N-acetylglucosamine (O-GlcNAc) Acts as a Glucose Sensor to Epigenetically Regulate the Insulin Gene in Pancreatic Beta Cells. J Biol Chem 2015; 291:2107-18. [PMID: 26598517 DOI: 10.1074/jbc.m115.693580] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Indexed: 11/06/2022] Open
Abstract
The post-translational protein modification O-linked β-N-acetylglucosamine (O-GlcNAc) is a proposed nutrient sensor that has been shown to regulate multiple biological pathways. This dynamic and inducible enzymatic modification to intracellular proteins utilizes the end product of the nutrient sensing hexosamine biosynthetic pathway, UDP-GlcNAc, as its substrate donor. Type II diabetic patients have elevated O-GlcNAc-modified proteins within pancreatic beta cells due to chronic hyperglycemia-induced glucose overload, but a molecular role for O-GlcNAc within beta cells remains unclear. Using directed pharmacological approaches in the mouse insulinoma-6 (Min6) cell line, we demonstrate that elevating nuclear O-GlcNAc increases intracellular insulin levels and preserves glucose-stimulated insulin secretion during chronic hyperglycemia. The molecular mechanism for these observed changes appears to be, at least in part, due to elevated O-GlcNAc-dependent increases in Ins1 and Ins2 mRNA levels via elevations in histone H3 transcriptional activation marks. Furthermore, RNA deep sequencing reveals that this mechanism of altered gene transcription is restricted and that the majority of genes regulated by elevated O-GlcNAc levels are similarly regulated by a shift from euglycemic to hyperglycemic conditions. These findings implicate the O-GlcNAc modification as a potential mechanism for hyperglycemic-regulated gene expression in the beta cell.
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Affiliation(s)
- Sean P Durning
- From the Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602-1516 and
| | - Heather Flanagan-Steet
- From the Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602-1516 and
| | - Nripesh Prasad
- HudsonAlpha Institute of Biotechnology, Genomic Services Laboratory, Huntsville, Alabama 35806
| | - Lance Wells
- From the Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602-1516 and
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Wu Q, Tang SG, Yuan ZM. Gremlin 2 inhibits adipocyte differentiation through activation of Wnt/β-catenin signaling. Mol Med Rep 2015; 12:5891-6. [PMID: 26239165 DOI: 10.3892/mmr.2015.4117] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 10/31/2014] [Indexed: 11/06/2022] Open
Abstract
The primary function of white adipose tissues is to store excess energy. The current study aimed to investigate the roles of Gremlin 2 (Grem2), a glycoprotein in adipogenesis. Using polymerase chain reaction‑based microarrays, it was determined that Grem2 was markedly downregulated in adipose tissues from obese animals and humans. In addition, 3T3‑L1 cells were used to investigate the details of the mechanisms underlying the anti‑adipogenic effects of Grem2. Grem2 expression was markedly decreased upon the induction of adipocyte differentiation, as demonstrated by reverse transcription‑quantitative polymerase chain reaction and western blot analysis. Notably, Grem2 overexpression inhibited adipogenesis, while knockdown of Grem2 led to an increase in adipogenesis. At the molecular level, Grem2 promotes nuclear translocation of β‑catenin, an integral Wnt signaling component. Consistently, inhibition of Wnt/β‑catenin signaling using a retrovirus targeting the β‑catenin coding region attenuated the anti‑adipogenic effects of Grem2. Therefore, to the best of our knowledge, the current study shows for the first time that Grem2 may be an important regulator of adipocyte differentiation.
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Affiliation(s)
- Qing Wu
- Department of Geriatrics Cardiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P.R. China
| | - Shi-Guo Tang
- Department of Endocrinology, Chongqing Ninth People's Hospital, Chongqing 400010, P.R. China
| | - Zhong-Ming Yuan
- Department of Geriatrics, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P.R. China
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27
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Palatinus JA, Das S. Your Father and Grandfather's Atrial Fibrillation: A Review of the Genetics of the Most Common Pathologic Cardiac Dysrhythmia. Curr Genomics 2015; 16:75-81. [PMID: 26085805 PMCID: PMC4467307 DOI: 10.2174/1389202916666150108222031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/24/2014] [Accepted: 01/06/2015] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) remains the most common pathologic dysrhythmia in humans with a prevalence of 1-2% of the total population and as high as 10% of the elderly. AF is an independent risk marker for cardiovascular mortality and morbidity, and given the increasing age of the population, represents an increasing burden of disease. Although age and hypertension are known risk factors for development of AF, the study of families with early onset AF revealed mutations in genes coding for ion channels and other proteins involved in electrotonic coupling as likely culprits for the pathology in select cases. Recent investigations using Genome-Wide Association Studies have revealed several single nucleotide polymorphisms (SNPs) that appear to be associated with AF and have highlighted new genes in the proximity of the SNPs that may potentially contribute to the development of the dysrhythmia. Here we review the genetics of AF and discuss how application of GWAS and next generation sequencing have advanced our knowledge of AF and further investigations may yield novel therapeutic targets for the disease.
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Affiliation(s)
- Joseph A Palatinus
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Saumya Das
- Cardiovascular Institute, Beth Israel Deaconess Medical Center, Boston, MA, USA
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28
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Christophersen IE, Ellinor PT. Genetics of atrial fibrillation: from families to genomes. J Hum Genet 2015; 61:61-70. [DOI: 10.1038/jhg.2015.44] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 03/27/2015] [Accepted: 04/07/2015] [Indexed: 12/19/2022]
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Tanwar V, Bylund JB, Hu J, Yan J, Walthall JM, Mukherjee A, Heaton WH, Wang WD, Potet F, Rai M, Kupershmidt S, Knapik EW, Hatzopoulos AK. Gremlin 2 promotes differentiation of embryonic stem cells to atrial fate by activation of the JNK signaling pathway. Stem Cells 2015; 32:1774-88. [PMID: 24648383 DOI: 10.1002/stem.1703] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/17/2014] [Accepted: 02/23/2014] [Indexed: 01/23/2023]
Abstract
The bone morphogenetic protein antagonist Gremlin 2 (Grem2) is required for atrial differentiation and establishment of cardiac rhythm during embryonic development. A human Grem2 variant has been associated with familial atrial fibrillation, suggesting that abnormal Grem2 activity causes arrhythmias. However, it is not known how Grem2 integrates into signaling pathways to direct atrial cardiomyocyte differentiation. Here, we demonstrate that Grem2 expression is induced concurrently with the emergence of cardiovascular progenitor cells during differentiation of mouse embryonic stem cells (ESCs). Grem2 exposure enhances the cardiogenic potential of ESCs by 20-120-fold, preferentially inducing genes expressed in atrial myocytes such as Myl7, Nppa, and Sarcolipin. We show that Grem2 acts upstream to upregulate proatrial transcription factors CoupTFII and Hey1 and downregulate atrial fate repressors Irx4 and Hey2. The molecular phenotype of Grem2-induced atrial cardiomyocytes was further supported by induction of ion channels encoded by Kcnj3, Kcnj5, and Cacna1d genes and establishment of atrial-like action potentials shown by electrophysiological recordings. We show that promotion of atrial-like cardiomyocytes is specific to the Gremlin subfamily of BMP antagonists. Grem2 proatrial differentiation activity is conveyed by noncanonical BMP signaling through phosphorylation of JNK and can be reversed by specific JNK inhibitors, but not by dorsomorphin, an inhibitor of canonical BMP signaling. Taken together, our data provide novel mechanistic insights into atrial cardiomyocyte differentiation from pluripotent stem cells and will assist the development of future approaches to study and treat arrhythmias.
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Affiliation(s)
- Vineeta Tanwar
- Department of Medicine, Division of Cardiovascular Medicine, Nashville, Tennessee, USA
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Animal model of Sar1b deficiency presents lipid absorption deficits similar to Anderson disease. J Mol Med (Berl) 2015; 93:165-76. [PMID: 25559265 DOI: 10.1007/s00109-014-1247-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 11/19/2014] [Accepted: 12/18/2014] [Indexed: 01/25/2023]
Abstract
Anderson disease (ANDD) or chylomicron retention disease (CMRD) is a rare, hereditary lipid malabsorption syndrome associated with mutations in the SAR1B gene that is characterized by failure to thrive and hypocholesterolemia. Although the SAR1B structure has been resolved and its role in formation of coat protein II (COPII)-coated carriers is well established, little is known about the requirement for SAR1B during embryogenesis. To address this question, we have developed a zebrafish model of Sar1b deficiency based on antisense oligonucleotide knockdown. We show that zebrafish sar1b is highly conserved among vertebrates; broadly expressed during development; and enriched in the digestive tract organs, brain, and craniofacial skeleton. Consistent with ANDD symptoms of chylomicron retention, we found that dietary lipids in Sar1b-deficient embryos accumulate in enterocytes. Transgenic expression analysis revealed that Sar1b is required for growth of exocrine pancreas and liver. Furthermore, we found abnormal differentiation and maturation of craniofacial cartilage associated with defects in procollagen II secretion and absence of select, neuroD-positive neurons of the midbrain and hindbrain. The model presented here will help to systematically dissect developmental roles of Sar1b and to discover molecular and cellular mechanisms leading to organ-specific ANDD pathology. Key messages: Sar1b depletion phenotype in zebrafish resembles Anderson disease deficits. Sar1b deficiency results in multi-organ developmental deficits. Sar1b is required for dietary cholesterol uptake into enterocytes.
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Weeke P, Denny JC, Basterache L, Shaffer C, Bowton E, Ingram C, Darbar D, Roden DM. Examining rare and low-frequency genetic variants previously associated with lone or familial forms of atrial fibrillation in an electronic medical record system: a cautionary note. ACTA ACUST UNITED AC 2014; 8:58-63. [PMID: 25410959 DOI: 10.1161/circgenetics.114.000718] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Studies in individuals or small kindreds have implicated rare variants in 25 different genes in lone and familial atrial fibrillation (AF) using linkage and segregation analysis, functional characterization, and rarity in public databases. Here, we used a cohort of 20 204 patients of European or African ancestry with electronic medical records and exome chip data to compare the frequency of AF among carriers and noncarriers of these rare variants. METHODS AND RESULTS The exome chip included 19 of 115 rare variants, in 9 genes, previously associated with lone or familial AF. Using validated algorithms querying a combination of clinical notes, structured billing codes, ECG reports, and procedure codes, we identified 1056 AF cases (>18 years) and 19 148 non-AF controls (>50 years) with available genotype data on the Illumina HumanExome BeadChip v.1.0 in the Vanderbilt electronic medical record-linked DNA repository, BioVU. Known correlations between AF and common variants at 4q25 were replicated. None of the 19 variants previously associated with AF were over-represented among AF cases (P>0.1 for all), and the frequency of variant carriers among non-AF controls was >0.1% for 14 of 19. Repeat analyses using non-AF controls aged >60 (n=14 904), >70 (n=9670), and >80 (n=4729) years did not influence these findings. CONCLUSIONS Rare variants previously implicated in lone or familial forms of AF present on the exome chip are detected at low frequencies in a general population but are not associated with AF. These findings emphasize the need for caution when ascribing variants as pathogenic or causative.
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Affiliation(s)
- Peter Weeke
- From the Department of Internal Medicine (P.W., J.C.D., C.S., C.I., D.D., D.M.R.) and Department of Biomedical Informatics (J.C.D., L.B.), Vanderbilt University Medical Center, Nashville, TN; Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark (P.W.); and Institute for Clinical and Translational Research, Vanderbilt University School of Medicine, Nashville, TN (E.B.)
| | - Joshua C Denny
- From the Department of Internal Medicine (P.W., J.C.D., C.S., C.I., D.D., D.M.R.) and Department of Biomedical Informatics (J.C.D., L.B.), Vanderbilt University Medical Center, Nashville, TN; Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark (P.W.); and Institute for Clinical and Translational Research, Vanderbilt University School of Medicine, Nashville, TN (E.B.)
| | - Lisa Basterache
- From the Department of Internal Medicine (P.W., J.C.D., C.S., C.I., D.D., D.M.R.) and Department of Biomedical Informatics (J.C.D., L.B.), Vanderbilt University Medical Center, Nashville, TN; Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark (P.W.); and Institute for Clinical and Translational Research, Vanderbilt University School of Medicine, Nashville, TN (E.B.)
| | - Christian Shaffer
- From the Department of Internal Medicine (P.W., J.C.D., C.S., C.I., D.D., D.M.R.) and Department of Biomedical Informatics (J.C.D., L.B.), Vanderbilt University Medical Center, Nashville, TN; Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark (P.W.); and Institute for Clinical and Translational Research, Vanderbilt University School of Medicine, Nashville, TN (E.B.)
| | - Erica Bowton
- From the Department of Internal Medicine (P.W., J.C.D., C.S., C.I., D.D., D.M.R.) and Department of Biomedical Informatics (J.C.D., L.B.), Vanderbilt University Medical Center, Nashville, TN; Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark (P.W.); and Institute for Clinical and Translational Research, Vanderbilt University School of Medicine, Nashville, TN (E.B.)
| | - Christie Ingram
- From the Department of Internal Medicine (P.W., J.C.D., C.S., C.I., D.D., D.M.R.) and Department of Biomedical Informatics (J.C.D., L.B.), Vanderbilt University Medical Center, Nashville, TN; Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark (P.W.); and Institute for Clinical and Translational Research, Vanderbilt University School of Medicine, Nashville, TN (E.B.)
| | - Dawood Darbar
- From the Department of Internal Medicine (P.W., J.C.D., C.S., C.I., D.D., D.M.R.) and Department of Biomedical Informatics (J.C.D., L.B.), Vanderbilt University Medical Center, Nashville, TN; Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark (P.W.); and Institute for Clinical and Translational Research, Vanderbilt University School of Medicine, Nashville, TN (E.B.)
| | - Dan M Roden
- From the Department of Internal Medicine (P.W., J.C.D., C.S., C.I., D.D., D.M.R.) and Department of Biomedical Informatics (J.C.D., L.B.), Vanderbilt University Medical Center, Nashville, TN; Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark (P.W.); and Institute for Clinical and Translational Research, Vanderbilt University School of Medicine, Nashville, TN (E.B.).
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Abstract
Atrial fibrillation (AF) is the most common arrhythmia and is associated with increased morbidity. As the population ages and the prevalence of AF continues to rise, the socioeconomic consequences of AF will become increasingly burdensome. Although there are well-defined clinical risk factors for AF, a significant heritable component is also recognized. To identify the molecular basis for the heritability of AF, investigators have used a combination of classical Mendelian genetics, candidate gene screening, and genome-wide association studies. However, these avenues have, as yet, failed to define the majority of the heritability of AF. The goal of this review is to describe the results from both candidate gene and genome-wide studies, as well as to outline potential future avenues for creating a more complete understanding of AF genetics. Ultimately, a more comprehensive view of the genetic underpinnings for AF will lead to the identification of novel molecular pathways and improved risk prediction of this complex arrhythmia.
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Affiliation(s)
- Nathan R Tucker
- From the Cardiovascular Research Center, Massachusetts General Hospital, Boston
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33
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Gremlin-2 is a BMP antagonist that is regulated by the circadian clock. Sci Rep 2014; 4:5183. [PMID: 24897937 PMCID: PMC4046123 DOI: 10.1038/srep05183] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 05/13/2014] [Indexed: 01/06/2023] Open
Abstract
Tendons are prominent members of the family of fibrous connective tissues (FCTs), which collectively are the most abundant tissues in vertebrates and have crucial roles in transmitting mechanical force and linking organs. Tendon diseases are among the most common arthropathy disorders; thus knowledge of tendon gene regulation is essential for a complete understanding of FCT biology. Here we show autonomous circadian rhythms in mouse tendon and primary human tenocytes, controlled by an intrinsic molecular circadian clock. Time-series microarrays identified the first circadian transcriptome of murine tendon, revealing that 4.6% of the transcripts (745 genes) are expressed in a circadian manner. One of these genes was Grem2, which oscillated in antiphase to BMP signaling. Moreover, recombinant human Gremlin-2 blocked BMP2-induced phosphorylation of Smad1/5 and osteogenic differentiation of human tenocytes in vitro. We observed dampened Grem2 expression, deregulated BMP signaling, and spontaneously calcifying tendons in young CLOCKΔ19 arrhythmic mice and aged wild-type mice. Thus, disruption of circadian control, through mutations or aging, of Grem2/BMP signaling becomes a new focus for the study of calcific tendinopathy, which affects 1-in-5 people over the age of 50 years.
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Olesen MS, Nielsen MW, Haunsø S, Svendsen JH. Atrial fibrillation: the role of common and rare genetic variants. Eur J Hum Genet 2014; 22:297-306. [PMID: 23838598 PMCID: PMC3925267 DOI: 10.1038/ejhg.2013.139] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 04/28/2013] [Accepted: 05/27/2013] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting 1-2% of the general population. A number of studies have demonstrated that AF, and in particular lone AF, has a substantial genetic component. Monogenic mutations in lone and familial AF, although rare, have been recognized for many years. Presently, mutations in 25 genes have been associated with AF. However, the complexity of monogenic AF is illustrated by the recent finding that both gain- and loss-of-function mutations in the same gene can cause AF. Genome-wide association studies (GWAS) have indicated that common single-nucleotide polymorphisms (SNPs) have a role in the development of AF. Following the first GWAS discovering the association between PITX2 and AF, several new GWAS reports have identified SNPs associated with susceptibility of AF. To date, nine SNPs have been associated with AF. The exact biological pathways involving these SNPs and the development of AF are now starting to be elucidated. Since the first GWAS, the number of papers concerning the genetic basis of AF has increased drastically and the majority of these papers are for the first time included in a review. In this review, we discuss the genetic basis of AF and the role of both common and rare genetic variants in the susceptibility of developing AF. Furthermore, all rare variants reported to be associated with AF were systematically searched for in the Exome Sequencing Project Exome Variant Server.
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Affiliation(s)
- Morten S Olesen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), Copenhagen, Denmark
- Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Morten W Nielsen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), Copenhagen, Denmark
- Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Stig Haunsø
- The Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), Copenhagen, Denmark
- Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Surgery and Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jesper H Svendsen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), Copenhagen, Denmark
- Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Surgery and Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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35
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Abstract
Atrial fibrillation (AF) is the most-common sustained arrhythmia observed in clinical practice, but response to therapy is highly variable between patients. Current drug therapies to suppress AF are incompletely and unpredictably effective and carry substantial risk of proarrhythmia and noncardiac toxicities. The limited success of therapy for AF is partially the result of heterogeneity of the underlying substrate, interindividual differences in disease mechanisms, and our inability to predict response to therapies in individual patients. In this Review, we discuss the evidence that variability in response to drug therapy is also conditioned by the underlying genetic substrate for AF. Increased susceptibility to AF is mediated through diverse genetic mechanisms, including modulation of the atrial action-potential duration, conduction slowing, and impaired cell-to-cell communication, as well as novel mechanisms, such as regulation of signalling proteins important in the pathogenesis of AF. However, the translation of genetic data to the care of the patients with AF has been limited because of poor understanding of the underlying mechanisms associated with common AF-susceptibility loci, a dearth of prospective, adequately powered studies, and the challenges associated with determining efficacy of antiarrhythmic drugs. What is apparent, however, is the need for appropriately designed, genotype-directed clinical trials.
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Affiliation(s)
- Dawood Darbar
- Departments of Medicine and Pharmacology, Vanderbilt University School of Medicine, 2215B Garland Avenue, Nashville, TN 37323-6602, USA.
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