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Abstract
The zebrafish has become a prominent vertebrate model for disease and has already contributed to several examples of successful phenotype-based drug discovery. For the zebrafish to become useful in drug development more broadly, key hurdles must be overcome, including a more comprehensive elucidation of the similarities and differences between human and zebrafish biology. Recent studies have begun to establish the capabilities and limitations of zebrafish for disease modelling, drug screening, target identification, pharmacology, and toxicology. As our understanding increases and as the technologies for manipulating zebrafish improve, it is hoped that the zebrafish will have a key role in accelerating the emergence of precision medicine.
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Musso G, Mosimann C, Panáková D, Burger A, Zhou Y, Zon LI, MacRae CA. Generating and evaluating a ranked candidate gene list for potential vertebrate heart field regulators. GENOMICS DATA 2015; 6:199-201. [PMID: 26697374 PMCID: PMC4664750 DOI: 10.1016/j.gdata.2015.09.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 09/12/2015] [Indexed: 11/20/2022]
Abstract
The vertebrate heart develops from two distinct lineages of cardiomyocytes that arise from the first and second heart fields (FHF and SHF, respectively). The FHF forms the primitive heart tube, while adding cells from the SHF allows elongation at both poles of the tube. Initially seen as an exclusive characteristic of higher vertebrates, recent work has demonstrated the presence of a distinct FHF and SHF in lower vertebrates, including zebrafish. We found that key transcription factors that regulate septation and chamber formation in higher vertebrates, including Tbx5 and Pitx2, influence relative FHF and SHF contributions to the zebrafish heart tube. To identify molecular modulators of heart field migration, we used microarray-based expression profiling following inhibition of tbx5a and pitx2ab in embryonic zebrafish (Mosimann & Panakova, et al, 2015; GSE70750). Here, we describe in more detail the procedure used to process, prioritize, and analyze the expression data for functional enrichment.
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128
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Stitziel NO, MacRae CA. A clinical approach to inherited premature coronary artery disease. ACTA ACUST UNITED AC 2015; 7:558-64. [PMID: 25140063 DOI: 10.1161/circgenetics.113.000152] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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129
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MacRae CA. In vitro and in vivo reprogramming for the conduction system. Trends Cardiovasc Med 2015; 26:21-2. [PMID: 26632016 DOI: 10.1016/j.tcm.2015.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 08/17/2015] [Indexed: 10/23/2022]
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130
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Treggiari D, Zoccatelli G, Molesini B, Degan M, Rotino GL, Sala T, Cavallini C, MacRae CA, Minuz P, Pandolfini T. A cystine-knot miniprotein from tomato fruit inhibits endothelial cell migration and angiogenesis by affecting vascular endothelial growth factor receptor (VEGFR) activation and nitric oxide production. Mol Nutr Food Res 2015; 59:2255-66. [PMID: 26255647 DOI: 10.1002/mnfr.201500267] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 06/29/2015] [Accepted: 07/23/2015] [Indexed: 01/23/2023]
Abstract
SCOPE Cystine-knot miniproteins are bioactive molecules with a broad range of potential therapeutic applications. Recently, it was demonstrated that two tomato cystine-knot miniproteins (TCMPs) exhibit in vitro antiangiogenic activity on human umbilical vein cells. The aim of the present study was to investigate the effects of a fruit-specific cystine-knot miniprotein of tomato on in vitro endothelial cell migration and in vivo angiogenesis using a zebrafish model. METHODS AND RESULTS The cystine-knot protein purified from tomato fruits using gel filtration LC and RP-HPLC inhibited cell migration when tested at 200 nM using the wound healing assay, and reduced nitric oxide formation probed by 4-amino-5-methylamino-27-difluorofluoscescin diacetate. RT-PCR and Western blot analyses demonstrated that vascular endothelium growth factor A dependent signaling was the target of TCMP bioactivity. Angiogenesis was inhibited in vivo in zebrafish embryos treated with 500 nM TCMP. CONCLUSION Our results demonstrate that cystine-knot miniproteins present in mature tomato fruits are endowed with antiangiogenic activity in vitro and in vivo. These molecules may confer beneficial effects to tomato dietary intake, along with lycopene and other antioxidants. Further investigation is warranted to explore the potential of these compounds as model scaffolds for the development of new drugs.
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Mahmoud AI, O'Meara CC, Gemberling M, Zhao L, Bryant DM, Zheng R, Gannon JB, Cai L, Choi WY, Egnaczyk GF, Burns CE, Burns CG, MacRae CA, Poss KD, Lee RT. Nerves Regulate Cardiomyocyte Proliferation and Heart Regeneration. Dev Cell 2015; 34:387-99. [PMID: 26256209 DOI: 10.1016/j.devcel.2015.06.017] [Citation(s) in RCA: 184] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 05/07/2015] [Accepted: 06/18/2015] [Indexed: 01/09/2023]
Abstract
Some organisms, such as adult zebrafish and newborn mice, have the capacity to regenerate heart tissue following injury. Unraveling the mechanisms of heart regeneration is fundamental to understanding why regeneration fails in adult humans. Numerous studies have revealed that nerves are crucial for organ regeneration, thus we aimed to determine whether nerves guide heart regeneration. Here, we show using transgenic zebrafish that inhibition of cardiac innervation leads to reduction of myocyte proliferation following injury. Specifically, pharmacological inhibition of cholinergic nerve function reduces cardiomyocyte proliferation in the injured hearts of both zebrafish and neonatal mice. Direct mechanical denervation impairs heart regeneration in neonatal mice, which was rescued by the administration of neuregulin 1 (NRG1) and nerve growth factor (NGF) recombinant proteins. Transcriptional analysis of mechanically denervated hearts revealed a blunted inflammatory and immune response following injury. These findings demonstrate that nerve function is required for both zebrafish and mouse heart regeneration.
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Korf B, Ahmadian R, Allanson J, Aoki Y, Bakker A, Wright EB, Denger B, Elgersma Y, Gelb BD, Gripp KW, Kerr B, Kontaridis M, Lazaro C, Linardic C, Lozano R, MacRae CA, Messiaen L, Mulero-Navarro S, Neel B, Plotkin S, Rauen KA, Roberts A, Silva AJ, Sittampalam SG, Zhang C, Schoyer L. The third international meeting on genetic disorders in the RAS/MAPK pathway: towards a therapeutic approach. Am J Med Genet A 2015; 167A:1741-6. [PMID: 25900621 PMCID: PMC4515140 DOI: 10.1002/ajmg.a.37089] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 03/15/2015] [Indexed: 12/15/2022]
Abstract
"The Third International Meeting on Genetic Disorders in the RAS/MAPK Pathway: Towards a Therapeutic Approach" was held at the Renaissance Orlando at SeaWorld Hotel (August 2-4, 2013). Seventy-one physicians and scientists attended the meeting, and parallel meetings were held by patient advocacy groups (CFC International, Costello Syndrome Family Network, NF Network and Noonan Syndrome Foundation). Parent and patient advocates opened the meeting with a panel discussion to set the stage regarding their hopes and expectations for therapeutic advances. In keeping with the theme on therapeutic development, the sessions followed a progression from description of the phenotype and definition of therapeutic endpoints, to definition of genomic changes, to identification of therapeutic targets in the RAS/MAPK pathway, to preclinical drug development and testing, to clinical trials. These proceedings will review the major points of discussion.
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Rider SA, Mullins LJ, Verdon RF, MacRae CA, Mullins JJ. Renin expression in developing zebrafish is associated with angiogenesis and requires the Notch pathway and endothelium. Am J Physiol Renal Physiol 2015. [PMID: 26202224 DOI: 10.1152/ajprenal.00247.2015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although renin is a critical regulatory enzyme of the cardiovascular system, its roles in organogenesis and the establishment of cardiovascular homeostasis remain unclear. Mammalian renin-expressing cells are widespread in embryonic kidneys but are highly restricted, specialized endocrine cells in adults. With a functional pronephros, embryonic zebrafish are ideal for delineating the developmental functions of renin-expressing cells and the mechanisms governing renin transcription. Larval zebrafish renin expression originates in the mural cells of the juxtaglomerular anterior mesenteric artery and subsequently at extrarenal sites. The role of renin was determined by assessing responses to renin-angiotensin system blockade, salinity variation, and renal perfusion ablation. Renin expression did not respond to renal flow ablation but was modulated by inhibition of angiotensin-converting enzyme and altered salinity. Our data in larval fish are consistent with conservation of renin's physiological functions. Using transgenic renin reporter fish, with mindbomb and cloche mutants, we show that Notch signaling and the endothelium are essential for developmental renin expression. After inhibition of angiogenesis, renin-expressing cells precede angiogenic sprouts. Arising from separate lineages, but relying on mutual interplay with endothelial cells, renin-expressing cells are among the earliest mural cells observed in larval fish, performing both endocrine and paracrine functions.
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Guan J, Mishra S, Qiu Y, Shi J, Trudeau K, Las G, Liesa M, Shirihai OS, Connors LH, Seldin DC, Falk RH, MacRae CA, Liao R. Lysosomal dysfunction and impaired autophagy underlie the pathogenesis of amyloidogenic light chain-mediated cardiotoxicity. EMBO Mol Med 2015; 7:688. [PMID: 25940533 PMCID: PMC4492824 DOI: 10.15252/emmm.201505318] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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135
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Guan J, Mishra S, Qiu Y, Shi J, Trudeau K, Las G, Liesa M, Shirihai OS, Connors LH, Seldin DC, Falk RH, MacRae CA, Liao R. Lysosomal dysfunction and impaired autophagy underlie the pathogenesis of amyloidogenic light chain-mediated cardiotoxicity. EMBO Mol Med 2015; 6:1493-507. [PMID: 25319546 PMCID: PMC4237473 DOI: 10.15252/emmm.201404190] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AL amyloidosis is the consequence of clonal production of amyloidogenic immunoglobulin light chain (LC) proteins, often resulting in a rapidly progressive and fatal amyloid cardiomyopathy. Recent work has found that amyloidogenic LC directly initiate a cardio-toxic response underlying the pathogenesis of the cardiomyopathy; however, the mechanisms that contribute to this proteotoxicity remain unknown. Using human amyloidogenic LC isolated from patients with amyloid cardiomyopathy, we reveal that dysregulation of autophagic flux is critical for mediating amyloidogenic LC proteotoxicity. Restoration of autophagic flux by pharmacological intervention using rapamycin protected against amyloidogenic light chain protein-induced pathologies including contractile dysfunction and cell death at the cellular and organ level and also prolonged survival in an in vivo zebrafish model of amyloid cardiotoxicity. Mechanistically, we identify impaired lysosomal function to be the major cause of defective autophagy and amyloidogenic LC-induced proteotoxicity. Collectively, these findings detail the downstream molecular mechanisms underlying AL amyloid cardiomyopathy and highlight potential targeting of autophagy and lysosomal dysfunction in patients with amyloid cardiomyopathy.
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Burns AR, Luciani GM, Musso G, Bagg R, Yeo M, Zhang Y, Rajendran L, Glavin J, Hunter R, Redman E, Stasiuk S, Schertzberg M, Angus McQuibban G, Caffrey CR, Cutler SR, Tyers M, Giaever G, Nislow C, Fraser AG, MacRae CA, Gilleard J, Roy PJ. Caenorhabditis elegans is a useful model for anthelmintic discovery. Nat Commun 2015; 6:7485. [PMID: 26108372 PMCID: PMC4491176 DOI: 10.1038/ncomms8485] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/13/2015] [Indexed: 12/13/2022] Open
Abstract
Parasitic nematodes infect one quarter of the world's population and impact all humans through widespread infection of crops and livestock. Resistance to current anthelmintics has prompted the search for new drugs. Traditional screens that rely on parasitic worms are costly and labour intensive and target-based approaches have failed to yield novel anthelmintics. Here, we present our screen of 67,012 compounds to identify those that kill the non-parasitic nematode Caenorhabditis elegans. We then rescreen our hits in two parasitic nematode species and two vertebrate models (HEK293 cells and zebrafish), and identify 30 structurally distinct anthelmintic lead molecules. Genetic screens of 19 million C. elegans mutants reveal those nematicides for which the generation of resistance is and is not likely. We identify the target of one lead with nematode specificity and nanomolar potency as complex II of the electron transport chain. This work establishes C. elegans as an effective and cost-efficient model system for anthelmintic discovery.
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Fox CS, Hall JL, Arnett DK, Ashley EA, Delles C, Engler MB, Freeman MW, Johnson JA, Lanfear DE, Liggett SB, Lusis AJ, Loscalzo J, MacRae CA, Musunuru K, Newby LK, O'Donnell CJ, Rich SS, Terzic A. Future translational applications from the contemporary genomics era: a scientific statement from the American Heart Association. Circulation 2015; 131:1715-36. [PMID: 25882488 DOI: 10.1161/cir.0000000000000211] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The field of genetics and genomics has advanced considerably with the achievement of recent milestones encompassing the identification of many loci for cardiovascular disease and variable drug responses. Despite this achievement, a gap exists in the understanding and advancement to meaningful translation that directly affects disease prevention and clinical care. The purpose of this scientific statement is to address the gap between genetic discoveries and their practical application to cardiovascular clinical care. In brief, this scientific statement assesses the current timeline for effective translation of basic discoveries to clinical advances, highlighting past successes. Current discoveries in the area of genetics and genomics are covered next, followed by future expectations, tools, and competencies for achieving the goal of improving clinical care.
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139
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Asimaki A, Kapoor S, Plovie E, Karin Arndt A, Adams E, Liu Z, James CA, Judge DP, Calkins H, Churko J, Wu JC, MacRae CA, Kléber AG, Saffitz JE. Identification of a new modulator of the intercalated disc in a zebrafish model of arrhythmogenic cardiomyopathy. Sci Transl Med 2015; 6:240ra74. [PMID: 24920660 DOI: 10.1126/scitranslmed.3008008] [Citation(s) in RCA: 196] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Arrhythmogenic cardiomyopathy (ACM) is characterized by frequent cardiac arrhythmias. To elucidate the underlying mechanisms and discover potential chemical modifiers, we created a zebrafish model of ACM with cardiac myocyte-specific expression of the human 2057del2 mutation in the gene encoding plakoglobin. A high-throughput screen identified SB216763 as a suppressor of the disease phenotype. Early SB216763 therapy prevented heart failure and reduced mortality in the fish model. Zebrafish ventricular myocytes that expressed 2057del2 plakoglobin exhibited 70 to 80% reductions in I(Na) and I(K1) current densities, which were normalized by SB216763. Neonatal rat ventricular myocytes that expressed 2057del2 plakoglobin recapitulated pathobiological features seen in patients with ACM, all of which were reversed or prevented by SB216763. The reverse remodeling observed with SB216763 involved marked subcellular redistribution of plakoglobin, connexin 43, and Nav1.5, but without changes in their total cellular content, implicating a defect in protein trafficking to intercalated discs. In further support of this mechanism, we observed SB216763-reversible, abnormal subcellular distribution of SAP97 (a protein known to mediate forward trafficking of Nav1.5 and Kir2.1) in rat cardiac myocytes expressing 2057del2 plakoglobin and in cardiac myocytes derived from induced pluripotent stem cells from two ACM probands with plakophilin-2 mutations. These observations pinpoint aberrant trafficking of intercalated disc proteins as a central mechanism in ACM myocyte injury and electrical abnormalities.
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140
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Vassy JL, McLaughlin HM, McLaughlin HL, MacRae CA, Seidman CE, Lautenbach D, Krier JB, Lane WJ, Kohane IS, Murray MF, McGuire AL, Rehm HL, Green RC. A one-page summary report of genome sequencing for the healthy adult. Public Health Genomics 2015; 18:123-9. [PMID: 25612602 DOI: 10.1159/000370102] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 11/25/2014] [Indexed: 11/19/2022] Open
Abstract
As genome sequencing technologies increasingly enter medical practice, genetics laboratories must communicate sequencing results effectively to nongeneticist physicians. We describe the design and delivery of a clinical genome sequencing report, including a one-page summary suitable for interpretation by primary care physicians. To illustrate our preliminary experience with this report, we summarize the genomic findings from 10 healthy participants in a study of genome sequencing in primary care.
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141
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Taşan M, Musso G, Hao T, Vidal M, MacRae CA, Roth FP. Selecting causal genes from genome-wide association studies via functionally coherent subnetworks. Nat Methods 2014; 12:154-9. [PMID: 25532137 DOI: 10.1038/nmeth.3215] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 11/24/2014] [Indexed: 12/27/2022]
Abstract
Genome-wide association (GWA) studies have linked thousands of loci to human diseases, but the causal genes and variants at these loci generally remain unknown. Although investigators typically focus on genes closest to the associated polymorphisms, the causal gene is often more distal. Reliance on published work to prioritize candidates is biased toward well-characterized genes. We describe a 'prix fixe' strategy and software that uses genome-scale shared-function networks to identify sets of mutually functionally related genes spanning multiple GWA loci. Using associations from ∼100 GWA studies covering ten cancer types, our approach outperformed the common alternative strategy in ranking known cancer genes. As more GWA loci are discovered, the strategy will have increased power to elucidate the causes of human disease.
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142
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McLaughlin HM, Ceyhan-Birsoy O, Christensen KD, Kohane IS, Krier J, Lane WJ, Lautenbach D, Lebo MS, Machini K, MacRae CA, Azzariti DR, Murray MF, Seidman CE, Vassy JL, Green RC, Rehm HL. A systematic approach to the reporting of medically relevant findings from whole genome sequencing. BMC MEDICAL GENETICS 2014; 15:134. [PMID: 25714468 PMCID: PMC4342199 DOI: 10.1186/s12881-014-0134-1] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 12/03/2014] [Indexed: 01/22/2023]
Abstract
Background The MedSeq Project is a randomized clinical trial developing approaches to assess the impact of integrating genome sequencing into clinical medicine. To facilitate the return of results of potential medical relevance to physicians and patients participating in the MedSeq Project, we sought to develop a reporting approach for the effective communication of such findings. Methods Genome sequencing was performed on the Illumina HiSeq platform. Variants were filtered, interpreted, and validated according to methods developed by the Laboratory for Molecular Medicine and consistent with current professional guidelines. The GeneInsight software suite, which is integrated with the Partners HealthCare electronic health record, was used for variant curation, report drafting, and delivery. Results We developed a concise 5–6 page Genome Report (GR) featuring a single-page summary of results of potential medical relevance with additional pages containing structured variant, gene, and disease information along with supporting evidence for reported variants and brief descriptions of associated diseases and clinical implications. The GR is formatted to provide a succinct summary of genomic findings, enabling physicians to take appropriate steps for disease diagnosis, prevention, and management in their patients. Conclusions Our experience highlights important considerations for the reporting of results of potential medical relevance and provides a framework for interpretation and reporting practices in clinical genome sequencing. Electronic supplementary material The online version of this article (doi:10.1186/s12881-014-0134-1) contains supplementary material, which is available to authorized users.
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143
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Deo RC, Musso G, Tasan M, Tang P, Poon A, Yuan C, Felix JF, Vasan RS, Beroukhim R, De Marco T, Kwok PY, MacRae CA, Roth FP. Prioritizing causal disease genes using unbiased genomic features. Genome Biol 2014; 15:534. [PMID: 25633252 PMCID: PMC4279789 DOI: 10.1186/s13059-014-0534-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 11/06/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Cardiovascular disease (CVD) is the leading cause of death in the developed world. Human genetic studies, including genome-wide sequencing and SNP-array approaches, promise to reveal disease genes and mechanisms representing new therapeutic targets. In practice, however, identification of the actual genes contributing to disease pathogenesis has lagged behind identification of associated loci, thus limiting the clinical benefits. RESULTS To aid in localizing causal genes, we develop a machine learning approach, Objective Prioritization for Enhanced Novelty (OPEN), which quantitatively prioritizes gene-disease associations based on a diverse group of genomic features. This approach uses only unbiased predictive features and thus is not hampered by a preference towards previously well-characterized genes. We demonstrate success in identifying genetic determinants for CVD-related traits, including cholesterol levels, blood pressure, and conduction system and cardiomyopathy phenotypes. Using OPEN, we prioritize genes, including FLNC, for association with increased left ventricular diameter, which is a defining feature of a prevalent cardiovascular disorder, dilated cardiomyopathy or DCM. Using a zebrafish model, we experimentally validate FLNC and identify a novel FLNC splice-site mutation in a patient with severe DCM. CONCLUSION Our approach stands to assist interpretation of large-scale genetic studies without compromising their fundamentally unbiased nature.
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Sun H, Al-Romaih KI, MacRae CA, Pollak MR. Human Kidney Disease-causing INF2 Mutations Perturb Rho/Dia Signaling in the Glomerulus. EBioMedicine 2014; 1:107-15. [PMID: 26086034 PMCID: PMC4457406 DOI: 10.1016/j.ebiom.2014.11.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 11/08/2014] [Accepted: 11/11/2014] [Indexed: 01/10/2023] Open
Abstract
Mutations in Inverted Formin 2 (INF2), a diaphanous formin family protein that regulates actin cytoskeleton dynamics, cause focal segmental glomerulosclerosis (FSGS) and Charcot-Marie-Tooth Disease (CMT) in humans. In addition to directly remodeling actin filaments in vitro, we have shown that INF2 regulates intracellular actin dynamics and actin dependent cellular behavior by opposing Rhoa/Dia signaling. As a step towards a better understanding of the human kidney disease, we wanted to explore the relevance of these findings to the in vivo situation. We used dose dependent knockdown of INF2 to first define an in vivo model and establish an overt glomerular phenotype in zebrafish. This simple assay was validated by rescue with wild type INF2 confirming the specificity of the findings. The edema, podocyte dysfunction, and an altered glomerular filtration barrier observed in the zebrafish pronephros correlate with mistrafficking of glomerular slit diaphragm proteins, defective slit-diaphragm signaling, and disinhibited diaphanous formin (mDia) activity. In contrast to wild-type human INF2, INF2 mutants associated with kidney disease fail to rescue the zINF2 morphant phenotype. Of particular interest, this INF2 knockdown phenotype is also rescued by loss of either RhoA or Dia2. This simple assay allows the demonstration that INF2 functions, at least in part, to modulate Dia-mediated Rho signaling, and that disease causing mutations specifically impair this regulatory function. These data support a model in which disease-associated diaphanous inhibitory domain (DID) mutants in INF2 interfere with its binding to and inhibition of Dia, leading to uncontrolled Rho/Dia signaling and perturbed actin dynamics. Methods to fine tune Rho signaling in the glomerulus may lead to new approaches to therapy in humans.
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145
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Kong SW, Lee IH, Leshchiner I, Krier J, Kraft P, Rehm HL, Green RC, Kohane IS, MacRae CA. Summarizing polygenic risks for complex diseases in a clinical whole-genome report. Genet Med 2014; 17:536-44. [PMID: 25341114 DOI: 10.1038/gim.2014.143] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 09/09/2014] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Disease-causing mutations and pharmacogenomic variants are of primary interest for clinical whole-genome sequencing. However, estimating genetic liability for common complex diseases using established risk alleles might one day prove clinically useful. METHODS We compared polygenic scoring methods using a case-control data set with independently discovered risk alleles in the MedSeq Project. For eight traits of clinical relevance in both the primary-care and cardiomyopathy study cohorts, we estimated multiplicative polygenic risk scores using 161 published risk alleles and then normalized them using the population median estimated from the 1000 Genomes Project. RESULTS Our polygenic score approach identified the overrepresentation of independently discovered risk alleles in cases as compared with controls using a large-scale genome-wide association study data set. In addition to normalized multiplicative polygenic risk scores and rank in a population, the disease prevalence and proportion of heritability explained by known common risk variants provide important context in the interpretation of modern multilocus disease risk models. CONCLUSION Our approach in the MedSeq Project demonstrates how complex trait risk variants from an individual genome can be summarized and reported for the general clinician and also highlights the need for definitive clinical studies to obtain reference data for such estimates and to establish clinical utility.
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Roder K, Werdich AA, Li W, Liu M, Kim TY, Organ-Darling LE, Moshal KS, Hwang JM, Lu Y, Choi BR, MacRae CA, Koren G. RING finger protein RNF207, a novel regulator of cardiac excitation. J Biol Chem 2014; 289:33730-40. [PMID: 25281747 DOI: 10.1074/jbc.m114.592295] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two recent studies (Newton-Cheh, C. et al. (2009) Common variants at ten loci influence QT interval duration in the QTGEN Study. Nat. Genet. 41, 399-406 and Pfeufer, A. et al. (2009) Common variants at ten loci modulate the QT interval duration in the QTSCD Study. Nat. Genet. 41, 407-414) identified an association, with genome-wide significance, between a single nucleotide polymorphism within the gene encoding RING finger protein 207 (RNF207) and the QT interval. We sought to determine the role of RNF207 in cardiac electrophysiology. Morpholino knockdown of RNF207 in zebrafish embryos resulted in action potential duration prolongation, occasionally a 2:1 atrioventricular block, and slowing of conduction velocity. Conversely, neonatal rabbit cardiomyocytes infected with RNF207-expressing adenovirus exhibited shortened action potential duration. Using transfections of U-2 OS and HEK293 cells, Western blot analysis and immunocytochemistry data demonstrate that RNF207 and the human ether-a-go-go-related gene (HERG) potassium channel interact and colocalize. Furthermore, RNF207 overexpression significantly elevated total and membrane HERG protein and HERG-encoded current density by ∼30-50%, which was dependent on the intact N-terminal RING domain of RNF207. Finally, coexpression of RNF207 and HSP70 increased HERG expression compared with HSP70 alone. This effect was dependent on the C terminus of RNF207. Taken together, the evidence is strong that RNF207 is an important regulator of action potential duration, likely via effects on HERG trafficking and localization in a heat shock protein-dependent manner.
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Hariharan V, Asimaki A, Michaelson JE, Plovie E, MacRae CA, Saffitz JE, Huang H. Arrhythmogenic right ventricular cardiomyopathy mutations alter shear response without changes in cell-cell adhesion. Cardiovasc Res 2014; 104:280-9. [PMID: 25253076 DOI: 10.1093/cvr/cvu212] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
AIMS The majority of patients diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) have mutations in genes encoding desmosomal proteins, raising the possibility that abnormal intercellular adhesion plays an important role in disease pathogenesis. We characterize cell mechanical properties and molecular responses to oscillatory shear stress in cardiac myocytes expressing mutant forms of the desmosomal proteins, plakoglobin and plakophilin, which are linked to ARVC in patients. METHODS AND RESULTS Cells expressing mutant plakoglobin or plakophilin showed no differences in cell-cell adhesion relative to controls, while knocking down these proteins weakened cell-cell adhesion. However, cells expressing mutant plakoglobin failed to increase the amount of immunoreactive signal for plakoglobin or N-cadherin at cell-cell junctions in response to shear stress, as seen in control cells. Cells expressing mutant plakophilin exhibited a similar attenuation in the shear-induced increase in junctional plakoglobin immunoreactive signal in response to shear stress, suggesting that the phenotype is independent of the type of mutant protein being expressed. Cells expressing mutant plakoglobin also showed greater myocyte apoptosis compared with controls. Apoptosis rates increased greatly in response to shear stress in cells expressing mutant plakoglobin, but not in controls. Abnormal responses to shear stress in cells expressing either mutant plakoglobin or plakophilin could be reversed by SB216763, a GSK3β inhibitor. CONCLUSIONS Desmosomal mutations linked to ARVC do not significantly affect cell mechanical properties, but cause myocytes to respond abnormally to mechanical stress through a mechanism involving GSK3β. These results may help explain why patients with ARVC experience disease exacerbations following strenuous exercise.
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Carr CW, Conner LM, McCarthy CA, Greenberg JO, Laskowski KR, Parambi RJ, Graham DA, Szent-Gyorgyi LE, Cirino AL, Ho CY, MacRae CA, Seidman CE, Ghazinouri R, Lakdawala NK. Abstract 351: Optimizing the Frequency of Surveillance Echocardiography in Clinically Stable Patients With Hypertrophic Cardiomyopathy. Circ Cardiovasc Qual Outcomes 2014. [DOI: 10.1161/circoutcomes.7.suppl_1.351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background:
Hypertrophic cardiomyopathy (HCM) affects 0.2% of the population and is an important cause of sudden cardiac death, heart failure and stroke. However, most patients with HCM experience normal longevity. Optimal longitudinal management of stable HCM patients is poorly defined, although consensus guidelines advise annual echocardiography (echo). We report the clinical impact of surveillance echo and a protocol to improve the efficiency of repeat testing in a cohort of HCM patients followed at one center.
Methods and Results:
A Standardized Clinical Assessment and Management Plan (SCAMP) was developed by clinicians, supported by a quality improvement (QI) team, to maximize the utility of cardiac imaging in patients with HCM. SCAMPs are an established approach to QI that aim to optimize outcomes and resource utilization through standardization of care. The HCM SCAMP was designed to achieve these goals through implementation of a practice algorithm, data capture at the time of outpatient encounters, and iterative analysis. This SCAMP recommended decreased frequency of surveillance echo in stable patients, from every 12 to every 24 months. Stability was defined as >3 years since diagnosis, stable symptoms for ≥2 years, >2 unchanged echos, and no family history of end stage HCM. All patients with HCM followed longitudinally in one HCM clinic from 7/17/13 to 12/15/13 (n=127) were enrolled. After excluding patients with a new diagnosis (n=16), no recent echo (n=15), or incomplete SCAMP documentation (n=1), 92 were included in this analysis. At enrollment, baseline echo (mean interval from prior echo: 15.8±5.8 months) identified clinically significant changes in 13 (14%) patients; including new pulmonary hypertension (n=6), and significant change (≥Δ50mmHg) or interval appearance of severe left ventricular outflow tract obstruction (LVOTO) (n=6). Clinical management was impacted by echo findings in 8/92 (9%); including medication adjustment (n=6), referral for exercise testing (n=2) and refined sudden cardiac death risk stratification (n=1). In the 79 patients with stable echo findings (86%), 25 (32%) were qualified by the SCAMP as clinically stable and were advised to undergo repeat echo in 24 (instead of 12) months. Providers adhered to this recommendation in 19 patients (76%). Reasons for deviating from recommendations and continuing annual echo in SCAMP defined stable patients included patient preference, atrial fibrillation, severe LVOTO, and pulmonary hypertension.
Conclusions:
In select clinically stable patients with HCM, repeat echo may be unlikely to identify significant changes or impact practice. In these patients, a decreased frequency of echocardiography could decrease resource utilization without compromising care. Ongoing data collection and better risk stratification tools may allow more targeted surveillance strategies in the future.
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Pieperhoff S, Wilson KS, Baily J, de Mora K, Maqsood S, Vass S, Taylor J, Del-Pozo J, MacRae CA, Mullins JJ, Denvir MA. Heart on a plate: histological and functional assessment of isolated adult zebrafish hearts maintained in culture. PLoS One 2014; 9:e96771. [PMID: 24824845 PMCID: PMC4019527 DOI: 10.1371/journal.pone.0096771] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 04/11/2014] [Indexed: 12/03/2022] Open
Abstract
The zebrafish is increasingly used for cardiovascular genetic and functional studies. We present a novel protocol to maintain and monitor whole isolated beating adult zebrafish hearts in culture for long-term experiments. Excised whole adult zebrafish hearts were transferred directly into culture dishes containing optimized L-15 Leibovitz growth medium and maintained for 5 days. Hearts were assessed daily using video-edge analysis of ventricle function using low power microscopy images. High-throughput histology techniques were used to assess changes in myocardial architecture and cell viability. Mean spontaneous Heart rate (HR, min−1) declined significantly between day 0 and day 1 in culture (96.7±19.5 to 45.2±8.2 min−1, mean±SD, p = 0.001), and thereafter declined more slowly to 27.6±7.2 min−1 on day 5. Ventricle wall motion amplitude (WMA) did not change until day 4 in culture (day 0, 46.7±13.0 µm vs day 4, 16.9±1.9 µm, p = 0.08). Contraction velocity (CV) declined between day 0 and day 3 (35.6±14.8 vs 15.2±5.3 µms−1, respectively, p = 0.012) while relaxation velocity (RV) declined quite rapidly (day 0, 72.5±11.9 vs day 1, 29.5±5.8 µms−1, p = 0.03). HR and WMA responded consistently to isoproterenol from day 0 to day 5 in culture while CV and RV showed less consistent responses to beta-agonist. Cellular architecture and cross-striation pattern of cardiomyocytes remained unchanged up to day 3 in culture and thereafter showed significant deterioration with loss of striation pattern, pyknotic nuclei and cell swelling. Apoptotic markers within the myocardium became increasingly frequent by day 3 in culture. Whole adult zebrafish hearts can be maintained in culture-medium for up to 3 days. However, after day-3 there is significant deterioration in ventricle function and heart rate accompanied by significant histological changes consistent with cell death and loss of cardiomyocyte cell integrity. Further studies are needed to assess whether this preparation can be optimised for longer term survival.
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150
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Abstract
Clinical and molecular genetics are inextricably linked. In the last two decades genetic studies have revealed the causes of several forms of structural heart disease. Recent work is extending the insights from inherited arrhythmias and cardiomyopathies to other forms of heart disease. In this review we outline the current state of the art for the genetics of adult structural heart disease, in particular the cardiomyopathies, valvular heart disease and aortic disease. The general approaches are described with a focus on clinical relevance, while potential areas for imminent innovation in diagnosis and therapeutics are highlighted.
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