101
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Kaptchuk TJ, Hemond CC, Miller FG. Placebos in chronic pain: evidence, theory, ethics, and use in clinical practice. BMJ 2020; 370:m1668. [PMID: 32690477 DOI: 10.1136/bmj.m1668] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Despite their ubiquitous presence, placebos and placebo effects retain an ambiguous and unsettling presence in biomedicine. Specifically focused on chronic pain, this review examines the effect of placebo treatment under three distinct frameworks: double blind, deception, and open label honestly prescribed. These specific conditions do not necessarily differentially modify placebo outcomes. Psychological, clinical, and neurological theories of placebo effects are scrutinized. In chronic pain, conscious expectation does not reliably predict placebo effects. A supportive patient-physician relationship may enhance placebo effects. This review highlights "predictive coding" and "bayesian brain" as emerging models derived from computational neurobiology that offer a unified framework to explain the heterogeneous evidence on placebos. These models invert the dogma of the brain as a stimulus driven organ to one in which perception relies heavily on learnt, top down, cortical predictions to infer the source of incoming sensory data. In predictive coding/bayesian brain, both chronic pain (significantly modulated by central sensitization) and its alleviation with placebo treatment are explicated as centrally encoded, mostly non-conscious, bayesian biases. The review then evaluates seven ways in which placebos are used in clinical practice and research and their bioethical implications. In this way, it shows that placebo effects are evidence based, clinically relevant, and potentially ethical tools for relieving chronic pain.
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Affiliation(s)
- Ted J Kaptchuk
- Beth Israel Hospital/Harvard Medical School, Boston, MA 02139, USA
- Contributed equally
| | - Christopher C Hemond
- University of Massachusetts Medical School, Worcester, MA 01655, USA
- Contributed equally
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102
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Abstract
The valves of the heart are crucial for ensuring that blood flows in one direction from the heart, through the lungs and back to the rest of the body. Heart valve development is regulated by complex interactions between different cardiac cell types and is subject to blood flow-driven forces. Recent work has begun to elucidate the important roles of developmental pathways, valve cell heterogeneity and hemodynamics in determining the structure and function of developing valves. Furthermore, this work has revealed that many key genetic pathways involved in cardiac valve development are also implicated in diseased valves. Here, we review recent discoveries that have furthered our understanding of the molecular, cellular and mechanosensitive mechanisms of valve development, and highlight new insights into congenital and acquired valve disease.
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Affiliation(s)
- Anna O'Donnell
- The Heart Institute, Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
- Molecular and Developmental Biology Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Katherine E Yutzey
- The Heart Institute, Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
- Molecular and Developmental Biology Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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103
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Roston A, Evans D, Gill H, McKinnon M, Isidor B, Cogné B, Mwenifumbo J, van Karnebeek C, An J, Jones SJM, Farrer M, Demos M, Connolly M, Gibson WT. SETD1B-associated neurodevelopmental disorder. J Med Genet 2020; 58:196-204. [PMID: 32546566 DOI: 10.1136/jmedgenet-2019-106756] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/11/2020] [Accepted: 04/14/2020] [Indexed: 01/04/2023]
Abstract
BACKGROUND Dysfunction of histone methyltransferases and chromatin modifiers has been implicated in complex neurodevelopmental syndromes and cancers. SETD1B encodes a lysine-specific methyltransferase that assists in transcriptional activation of genes by depositing H3K4 methyl marks. Previous reports of patients with rare variants in SETD1B describe a distinctive phenotype that includes seizures, global developmental delay and intellectual disability. METHODS Two of the patients described herein were identified via genome-wide and exome-wide testing, with microarray and research-based exome, through the CAUSES (Clinical Assessment of the Utility of Sequencing and Evaluation as a Service) Research Clinic at the University of British Columbia. The third Vancouver patient had clinical trio exome sequencing through Blueprint Genetics. The fourth patient underwent singleton exome sequencing in Nantes, with subsequent recruitment to this cohort through GeneMatcher. RESULTS Here we present clinical reports of four patients with rare coding variants in SETD1B that demonstrate a shared phenotype, including intellectual disability, language delay, conserved musculoskeletal findings and seizures that may be treatment-refractory. We include supporting evidence from next-generation sequencing among a cohort of paediatric patients with epilepsy. CONCLUSION Rare coding variants in SETD1B can cause a diagnosable syndrome and could contribute as a risk factor for epilepsy, autism and other neurodevelopmental phenotypes. In the long term, some patients may also be at increased risk for cancers and other complex diseases. Thus, longitudinal studies are required to further elucidate the precise role of SETD1B in neurodevelopmental disorders and other systemic disease.
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Affiliation(s)
- Alexandra Roston
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Dan Evans
- Centre for Applied Neurogenetics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Harinder Gill
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada.,Provincial Medical Genetics Program, BC Women's Hospital and Health Centre, Vancouver, British Columbia, Canada
| | - Margaret McKinnon
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Bertrand Isidor
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, Pays de la Loire, France
| | - Benjamin Cogné
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nantes, Nantes, Pays de la Loire, France.,INSERM, CNRS, UNIV Nantes, l'institut du thorax, Nantes, Frances
| | - Jill Mwenifumbo
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Clara van Karnebeek
- Department of Pediatrics, Emma Children's Hospital, Amsterdam Gastroenterology and Metabolism, Amsterdam University Medical Centres, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatrics, Radboud Centre for Mitochondrial Medicine, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Jianghong An
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, Vancouver, British Columbia, Canada
| | - Matthew Farrer
- Centre for Applied Neurogenetics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Michelle Demos
- Division of Neurology, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mary Connolly
- Division of Neurology, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - William T Gibson
- Department of Medical Genetics, The University of British Columbia, Vancouver, British Columbia, Canada
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104
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Abstract
The mechanisms that regulate the balance between stem cell duplication and differentiation in adult tissues remain in debate. Using a combination of genetic lineage tracing and marker-based assays, the quantitative statistical analysis of clone size and cell composition has provided insights into the patterns of stem cell fate across a variety of tissue types and organisms. These studies have emphasized the role of niche factors and environmental cues in promoting stem cell competence, fate priming, and stochastic renewal programs. At the same time, evidence for injury-induced "cellular reprogramming" has revealed the remarkable flexibility of cell states, allowing progenitors to reacquire self-renewal potential during regeneration. Together, these findings have questioned the nature of stem cell identity and function. Here, focusing on a range of canonical tissue types, we review how quantitative modeling-based approaches have uncovered conserved patterns of stem cell fate and provided new insights into the mechanisms that regulate self-renewal.
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Affiliation(s)
- Lemonia Chatzeli
- Wellcome Trust/CRUK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
- Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge CB2 1QR, United Kingdom
| | - Benjamin D Simons
- Wellcome Trust/CRUK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
- Wellcome Trust/MRC Stem Cell Institute, University of Cambridge, Cambridge CB2 1QR, United Kingdom
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge CB3 0WA, United Kingdom
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105
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Contribution of a GATA4-Expressing Hematopoietic Progenitor Lineage to the Adult Mouse Endothelium. Cells 2020; 9:cells9051257. [PMID: 32438714 PMCID: PMC7290801 DOI: 10.3390/cells9051257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/17/2020] [Accepted: 05/18/2020] [Indexed: 11/17/2022] Open
Abstract
Different sources have been claimed for the embryonic origin of the coronary endothelium. Recently, the potential of circulating cells as progenitors of the cardiac endothelium has also been suggested. In a previous study we have shown that circulating progenitors are recruited by the embryonic endocardium and incorporated into the coronary vessels. These progenitors derive from a mesodermal lineage characterized by the expression of Gata4 under control of the enhancer G2. Herein, we aim to trace this specific lineage throughout postnatal stages. We have found that more than 50% of the adult cardiac endothelium derives from the G2-GATA4 lineage. This percentage increases from embryos to adults probably due to differential proliferation and postnatal recruitment of circulating endothelial progenitors. In fact, injection of fetal liver or placental cells in the blood stream of neonates leads to incorporation of G2-GATA4 lineage cells to the coronary endothelium. On the other hand, labeling of the hematopoietic lineage by the stage E7.5 also resulted in positive coronary endothelial cells from both, embryos and adults. Our results suggest that early hematopoietic progenitors recruited by the embryonic ventricular endocardium can become the predominant source of definitive endothelium during the vascularization of the heart.
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106
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Ulisse V, Dey S, Rothbard DE, Zeevi E, Gokhman I, Dadosh T, Minis A, Yaron A. Regulation of axonal morphogenesis by the mitochondrial protein Efhd1. Life Sci Alliance 2020; 3:3/7/e202000753. [PMID: 32414840 PMCID: PMC7232985 DOI: 10.26508/lsa.202000753] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 12/12/2022] Open
Abstract
During development, neurons adjust their energy balance to meet the high demands of robust axonal growth and branching. The mechanisms that regulate this tuning are largely unknown. Here, we show that sensory neurons lacking liver kinase B1 (Lkb1), a master regulator of energy homeostasis, exhibit impaired axonal growth and branching. Biochemical analysis of these neurons revealed reduction in axonal ATP levels, whereas transcriptome analysis uncovered down-regulation of Efhd1 (EF-hand domain family member D1), a mitochondrial Ca2+-binding protein. Genetic ablation of Efhd1 in mice resulted in reduced axonal morphogenesis as well as enhanced neuronal death. Strikingly, this ablation causes mitochondrial dysfunction and a decrease in axonal ATP levels. Moreover, Efhd1 KO sensory neurons display shortened mitochondria at the axonal growth cones, activation of the AMP-activated protein kinase (AMPK)-Ulk (Unc-51-like autophagy-activating kinase 1) pathway and an increase in autophagic flux. Overall, this work uncovers a new mitochondrial regulator that is required for axonal morphogenesis.
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Affiliation(s)
- Valeria Ulisse
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Swagata Dey
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Deborah E Rothbard
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Einav Zeevi
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Irena Gokhman
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Tali Dadosh
- Department of Chemical Research Support, Faculty of Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Adi Minis
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Avraham Yaron
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
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107
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Farias J, Holt CE, Sotelo JR, Sotelo-Silveira JR. Axon microdissection and transcriptome profiling reveals the in vivo RNA content of fully differentiated myelinated motor axons. RNA (NEW YORK, N.Y.) 2020; 26:595-612. [PMID: 32051223 PMCID: PMC7161357 DOI: 10.1261/rna.073700.119] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/31/2020] [Indexed: 05/23/2023]
Abstract
Axonal protein synthesis has been shown to play a role in developmental and regenerative growth, as well as in the maintenance of the axoplasm in a steady state. Recent studies have begun to identify the mRNAs localized in axons, which could be translated locally under different conditions. Despite that by now hundreds or thousands of mRNAs have been shown to be localized into the axonal compartment of cultured neurons in vitro, knowledge of which mRNAs are localized in mature myelinated axons is quite limited. With the purpose of characterizing the transcriptome of mature myelinated motor axons of peripheral nervous systems, we modified the axon microdissection method devised by Koenig, enabling the isolation of the axoplasm RNA to perform RNA-seq analysis. The transcriptome analysis indicates that the number of RNAs detected in mature axons is lower in comparison with in vitro data, depleted of glial markers, and enriched in neuronal markers. The mature myelinated axons are enriched for mRNAs related to cytoskeleton, translation, and oxidative phosphorylation. Moreover, it was possible to define core genes present in axons when comparing our data with transcriptomic data of axons grown in different conditions. This work provides evidence that axon microdissection is a valuable method to obtain genome-wide data from mature and myelinated axons of the peripheral nervous system, and could be especially useful for the study of axonal involvement in neurodegenerative pathologies of motor neurons such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophies (SMA).
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Affiliation(s)
- Joaquina Farias
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, 11600, Uruguay
- Departamento de Proteínas y Ácidos Nucléicos, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, 11600, Uruguay
| | - Christine E Holt
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3DY, United Kingdom
| | - José R Sotelo
- Departamento de Proteínas y Ácidos Nucléicos, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, 11600, Uruguay
| | - José R Sotelo-Silveira
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, 11600, Uruguay
- Departamento de Biología Celular y Molecular, Facultad de Ciencias, Universidad de la República, Montevideo, 11400, Uruguay
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108
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Carmona R, Barrena S, López Gambero AJ, Rojas A, Muñoz-Chápuli R. Epicardial cell lineages and the origin of the coronary endothelium. FASEB J 2020; 34:5223-5239. [PMID: 32068311 DOI: 10.1096/fj.201902249rr] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/07/2020] [Accepted: 02/02/2020] [Indexed: 11/11/2022]
Abstract
The embryonic epicardium generates a population of epicardial-derived mesenchymal cells (EPDC) whose contribution to the coronary endothelium is minor or, according to some reports, negligible. We have compared four murine cell-tracing models related to the EPDC in order to elucidate this contribution. Cre recombinase was expressed under control of the promoters of the Wilms' tumor suppressor (Wt1), the cardiac troponin (cTnT), and the GATA5 genes, activating expression of the R26REYFP reporter. We have also used the G2 enhancer of the GATA4 gene as a driver due to its activation in the proepicardium. Recombination was found in most of the epicardium/EPDC in all cases. The contribution of these lineages to the cardiac endothelium was analyzed using confocal microscopy and flow cytometry. G2-GATA4 lineage cells are the most frequent in the endothelium, probably due to the recruitment of circulating endothelial progenitors. The contribution of the WT1 cell lineage increases along gestation due to further endothelial expression of WT1. GATA5 and cTnT lineages represent 4% of the cardiac endothelial cells throughout the gestation, probably standing for the actual EPDC contribution to the coronary endothelium. These results suggest caution when using a sole cell-tracing model to study the fate of the EPDC.
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Affiliation(s)
- Rita Carmona
- Department of Animal Biology, Faculty of Science, University of Málaga, Málaga, Spain.,Andalusian Center for Nanomedicine and Biotechnology (BIONAND), Málaga, Spain.,Institute of Biomedical Research of Málaga (IBIMA), Málaga, Spain
| | - Silvia Barrena
- Department of Animal Biology, Faculty of Science, University of Málaga, Málaga, Spain.,Andalusian Center for Nanomedicine and Biotechnology (BIONAND), Málaga, Spain.,Institute of Biomedical Research of Málaga (IBIMA), Málaga, Spain
| | - Antonio Jesús López Gambero
- Department of Animal Biology, Faculty of Science, University of Málaga, Málaga, Spain.,Andalusian Center for Nanomedicine and Biotechnology (BIONAND), Málaga, Spain.,Institute of Biomedical Research of Málaga (IBIMA), Málaga, Spain
| | - Anabel Rojas
- Andalusian Center of Molecular Biology and Regenerative Medicine (CABIMER), Sevilla, Spain.,Center for Biomedical Research in Diabetes and Associated Metabolic Disorders (CIBERDEM), Sevilla, Spain
| | - Ramón Muñoz-Chápuli
- Department of Animal Biology, Faculty of Science, University of Málaga, Málaga, Spain.,Andalusian Center for Nanomedicine and Biotechnology (BIONAND), Málaga, Spain.,Institute of Biomedical Research of Málaga (IBIMA), Málaga, Spain
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109
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Subramanian B, Chun J, Perez-Gill C, Yan P, Stillman IE, Higgs HN, Alper SL, Schlöndorff JS, Pollak MR. FSGS-Causing INF2 Mutation Impairs Cleaved INF2 N-Fragment Functions in Podocytes. J Am Soc Nephrol 2020; 31:374-391. [PMID: 31924668 DOI: 10.1681/asn.2019050443] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 11/11/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Mutations in the gene encoding inverted formin-2 (INF2), a member of the formin family of actin regulatory proteins, are among the most common causes of autosomal dominant FSGS. INF2 is regulated by interaction between its N-terminal diaphanous inhibitory domain (DID) and its C-terminal diaphanous autoregulatory domain (DAD). INF2 also modulates activity of other formins, such as the mDIA subfamily, and promotes stable microtubule assembly. Why the disease-causing mutations are restricted to the N terminus and how they cause human disease has been unclear. METHODS We examined INF2 isoforms present in podocytes and evaluated INF2 cleavage as an explanation for immunoblot findings. We evaluated the expression of INF2 N- and C-terminal fragments in human kidney disease conditions. We also investigated the localization and functions of the DID-containing N-terminal fragment in podocytes and assessed whether the FSGS-associated R218Q mutation impairs INF2 cleavage or the function of the N-fragment. RESULTS The INF2-CAAX isoform is the predominant isoform in podocytes. INF2 is proteolytically cleaved, a process mediated by cathepsin proteases, liberating the N-terminal DID to function independently. Although the N-terminal region normally localizes to podocyte foot processes, it does not do so in the presence of FSGS-associated INF2 mutations. The C-terminal fragment localizes to the cell body irrespective of INF2 mutations. In podocytes, the N-fragment localizes to the plasma membrane, binds mDIA1, and promotes cell spreading in a cleavage-dependent way. The disease-associated R218Q mutation impairs these N-fragment functions but not INF2 cleavage. CONCLUSIONS INF2 is cleaved into an N-terminal DID-containing fragment and a C-terminal DAD-containing fragment. Cleavage allows the N-terminal fragment to function independently and helps explain the clustering of FSGS-associated mutations.
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Affiliation(s)
| | - Justin Chun
- Division of Nephrology, Department of Medicine, and
| | | | - Paul Yan
- Division of Nephrology, Department of Medicine, and
| | - Isaac E Stillman
- Department of Pathology, Beth Israel Deaconess Medical center, Harvard Medical School, Boston, Massachusetts
| | - Henry N Higgs
- Department of Biochemistry, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; and
| | - Seth L Alper
- Division of Nephrology, Department of Medicine, and.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
| | | | - Martin R Pollak
- Division of Nephrology, Department of Medicine, and .,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts
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110
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Maleki S, Poujade FA, Bergman O, Gådin JR, Simon N, Lång K, Franco-Cereceda A, Body SC, Björck HM, Eriksson P. Endothelial/Epithelial Mesenchymal Transition in Ascending Aortas of Patients With Bicuspid Aortic Valve. Front Cardiovasc Med 2019; 6:182. [PMID: 31921896 PMCID: PMC6928128 DOI: 10.3389/fcvm.2019.00182] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 11/21/2019] [Indexed: 12/12/2022] Open
Abstract
Thoracic aortic aneurysm (TAA) is the progressive enlargement of the aorta due to destructive changes in the connective tissue of the aortic wall. Aneurysm development is silent and often first manifested by the drastic events of aortic dissection or rupture. As yet, therapeutic agents that halt or reverse the process of aortic wall deterioration are absent, and the only available therapeutic recommendation is elective prophylactic surgical intervention. Being born with a bicuspid instead of the normal tricuspid aortic valve (TAV) is a major risk factor for developing aneurysm in the ascending aorta later in life. Although the pathophysiology of the increased aneurysm susceptibility is not known, recent studies are suggestive of a transformation of aortic endothelium into a more mesenchymal state i.e., an endothelial-to-mesenchymal transition in these individuals. This process involves the loss of endothelial cell features, resulting in junction instability and enhanced vascular permeability of the ascending aorta that may lay the ground for increased aneurysm susceptibility. This finding differentiates and further emphasizes the specific characteristics of aneurysm development in individuals with a bicuspid aortic valve (BAV). This review discusses the possibility of a developmental fate shared between the aortic endothelium and aortic valves. It further speculates about the impact of aortic endothelium phenotypic shift on aneurysm development in individuals with a BAV and revisits previous studies in the light of the new findings.
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Affiliation(s)
- Shohreh Maleki
- Cardiovascular Medicine Unit, Center for Molecular Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Flore-Anne Poujade
- Cardiovascular Medicine Unit, Center for Molecular Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Otto Bergman
- Cardiovascular Medicine Unit, Center for Molecular Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Jesper R Gådin
- Cardiovascular Medicine Unit, Center for Molecular Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Nancy Simon
- Cardiovascular Medicine Unit, Center for Molecular Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Karin Lång
- Cardiovascular Medicine Unit, Center for Molecular Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Anders Franco-Cereceda
- Cardiothoracic Surgery Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Simon C Body
- Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Hanna M Björck
- Cardiovascular Medicine Unit, Center for Molecular Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Per Eriksson
- Cardiovascular Medicine Unit, Center for Molecular Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
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111
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Anton V, Buntenbroich I, Schuster R, Babatz F, Simões T, Altin S, Calabrese G, Riemer J, Schauss A, Escobar-Henriques M. Plasticity in salt bridge allows fusion-competent ubiquitylation of mitofusins and Cdc48 recognition. Life Sci Alliance 2019; 2:e201900491. [PMID: 31740565 PMCID: PMC6861704 DOI: 10.26508/lsa.201900491] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/06/2019] [Accepted: 11/07/2019] [Indexed: 01/08/2023] Open
Abstract
Mitofusins are dynamin-related GTPases that drive mitochondrial fusion by sequential events of oligomerization and GTP hydrolysis, followed by their ubiquitylation. Here, we show that fusion requires a trilateral salt bridge at a hinge point of the yeast mitofusin Fzo1, alternatingly forming before and after GTP hydrolysis. Mutations causative of Charcot-Marie-Tooth disease massively map to this hinge point site, underlining the disease relevance of the trilateral salt bridge. A triple charge swap rescues the activity of Fzo1, emphasizing the close coordination of the hinge residues with GTP hydrolysis. Subsequently, ubiquitylation of Fzo1 allows the AAA-ATPase ubiquitin-chaperone Cdc48 to resolve Fzo1 clusters, releasing the dynamin for the next fusion round. Furthermore, cross-complementation within the oligomer unexpectedly revealed ubiquitylated but fusion-incompetent Fzo1 intermediates. However, Cdc48 did not affect the ubiquitylated but fusion-incompetent variants, indicating that Fzo1 ubiquitylation is only controlled after membrane merging. Together, we present an integrated model on how mitochondrial outer membranes fuse, a critical process for their respiratory function but also putatively relevant for therapeutic interventions.
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Affiliation(s)
- Vincent Anton
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Ira Buntenbroich
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Ramona Schuster
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | | | - Tânia Simões
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Selver Altin
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Gaetano Calabrese
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Cologne, Germany
| | - Jan Riemer
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Cologne, Germany
| | | | - Mafalda Escobar-Henriques
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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112
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McSwiggen DT, Mir M, Darzacq X, Tjian R. Evaluating phase separation in live cells: diagnosis, caveats, and functional consequences. Genes Dev 2019; 33:1619-1634. [PMID: 31594803 PMCID: PMC6942051 DOI: 10.1101/gad.331520.119] [Citation(s) in RCA: 376] [Impact Index Per Article: 75.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The idea that liquid-liquid phase separation (LLPS) may be a general mechanism by which molecules in the complex cellular milieu may self-organize has generated much excitement and fervor in the cell biology community. While this concept is not new, its rise to preeminence has resulted in renewed interest in the mechanisms that shape and drive diverse cellular self-assembly processes from gene expression to cell division to stress responses. In vitro biochemical data have been instrumental in deriving some of the fundamental principles and molecular grammar by which biological molecules may phase separate, and the molecular basis of these interactions. Definitive evidence is lacking as to whether the same principles apply in the physiological environment inside living cells. In this Perspective, we analyze the evidence supporting phase separation in vivo across multiple cellular processes. We find that the evidence for in vivo LLPS is often phenomenological and inadequate to discriminate between phase separation and other possible mechanisms. Moreover, the causal relationship and functional consequences of LLPS in vivo are even more elusive. We underscore the importance of performing quantitative measurements on proteins in their endogenous state and physiological abundance, as well as make recommendations for experiments that may yield more conclusive results.
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Affiliation(s)
- David T McSwiggen
- Department of Molecular and Cell Biology, University of California Berkeley, California 94720, USA
- California Institute of Regenerative Medicine Center of Excellence, University of California Berkeley, California 94720, USA
| | - Mustafa Mir
- Department of Molecular and Cell Biology, University of California Berkeley, California 94720, USA
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California Berkeley, California 94720, USA
- California Institute of Regenerative Medicine Center of Excellence, University of California Berkeley, California 94720, USA
| | - Robert Tjian
- Department of Molecular and Cell Biology, University of California Berkeley, California 94720, USA
- Howard Hughes Medical Institute, University of California Berkeley, California 94720, USA
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113
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Odelin G, Faure E, Maurel-Zaffran C, Zaffran S. Krox20 Regulates Endothelial Nitric Oxide Signaling in Aortic Valve Development and Disease. J Cardiovasc Dev Dis 2019; 6:jcdd6040039. [PMID: 31684048 PMCID: PMC6955692 DOI: 10.3390/jcdd6040039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/25/2019] [Accepted: 10/31/2019] [Indexed: 12/18/2022] Open
Abstract
Among the aortic valve diseases, the bicuspid aortic valve (BAV) occurs when the aortic valve has two leaflets (cusps), rather than three, and represents the most common form of congenital cardiac malformation, affecting 1–2% of the population. Despite recent advances, the etiology of BAV is poorly understood. We have recently shown that Krox20 is expressed in endothelial and cardiac neural crest derivatives that normally contribute to aortic valve development and that lack of Krox20 in these cells leads to aortic valve defects including partially penetrant BAV formation. Dysregulated expression of endothelial nitric oxide synthase (Nos3) is associated with BAV. To investigate the relationship between Krox20 and Nos3 during aortic valve development, we performed inter-genetic cross. While single heterozygous mice had normal valve formation, the compound Krox20+/−;Nos3+/− mice had BAV malformations displaying an in vivo genetic interaction between these genes for normal valve morphogenesis. Moreover, in vivo and in vitro experiments demonstrate that Krox20 directly binds to Nos3 proximal promoter to activate its expression. Our data suggests that Krox20 is a regulator of nitric oxide in endothelial-derived cells in the development of the aortic valve and concludes on the interaction of Krox20 and Nos3 in BAV formation.
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Affiliation(s)
- Gaëlle Odelin
- Aix Marseille University, INSERM, Marseille Medical Genetics, U1251, 13005 Marseille, France.
| | - Emilie Faure
- Aix Marseille University, INSERM, Marseille Medical Genetics, U1251, 13005 Marseille, France.
| | | | - Stéphane Zaffran
- Aix Marseille University, INSERM, Marseille Medical Genetics, U1251, 13005 Marseille, France.
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114
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Munro L, Ladefoged LK, Padmanathan V, Andersen S, Schiøtt B, Kristensen AS. Conformational Changes in the 5-HT 3A Receptor Extracellular Domain Measured by Voltage-Clamp Fluorometry. Mol Pharmacol 2019; 96:720-734. [PMID: 31582575 DOI: 10.1124/mol.119.116657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 09/28/2019] [Indexed: 01/13/2023] Open
Abstract
The 5-hydroxytryptamine (5-HT) type 3 receptor is a member of the cysteine (Cys)-loop receptor super family of ligand-gated ion channels in the nervous system and is a clinical target in a range of diseases. The 5-HT3 receptor mediates fast serotonergic neurotransmission by undergoing a series of conformational changes initiated by ligand binding that lead to the rapid opening of an intrinsic cation-selective channel. However, despite the availability of high-resolution structures of a mouse 5-HT3 receptor, many important aspects of the mechanistic basis of 5-HT3 receptor function and modulation by drugs remain poorly understood. In particular, there is little direct evidence for the specific conformational changes predicted to occur during ligand-gated channel activation and desensitization. In the present study, we used voltage-clamp fluorometry (VCF) to measure conformational changes in regions surrounding the orthosteric binding site of the human 5-HT3A (h5-HT3A) receptor during binding of 5-HT and different classes of 5-HT3 receptor ligands. VCF utilizes parallel measurements of receptor currents with photon emission from fluorescent reporter groups covalently attached to specific positions in the receptor structure. Reporter groups that are highly sensitive to the local molecular environment can, in real time, report conformational changes as changes in fluorescence that can be correlated with changes in receptor currents reporting the functional states of the channel. Within the loop C, D, and E regions that surround the orthosteric binding site in the h5-HT3A receptor, we identify positions that are amenable to tagging with an environmentally sensitive reporter group that reports robust fluorescence changes upon 5-HT binding and receptor activation. We use these reporter positions to characterize the effect of ligand binding on the local structure of the orthosteric binding site by agonists, competitive antagonists, and allosterically acting channel activators. We observed that loop C appears to show distinct fluorescence changes for ligands of the same class, while loop D reports similar fluorescence changes for all ligands binding at the orthosteric site. In contrast, the loop E reporter position shows distinct changes for agonists, antagonists, and allosteric compounds, suggesting the conformational changes in this region are specific to ligand function. Interpretation of these results within the framework of current models of 5-HT3 and Cys-loop mechanisms are used to expand the understanding of how ligand binding in Cys-loop receptors relates to channel gating. SIGNIFICANCE STATEMENT: The 5-HT3 receptor is an important ligand-gated ion channel and drug target in the central and peripheral nervous system. Determining how ligand binding induced conformational changes in the receptor is central for understanding the structural mechanisms underlying 5-HT3 receptor function. Here, we employ voltage-gated fluorometry to characterize conformational changes in the extracellular domain of the human 5-HT3 receptor to identify intrareceptor motions during binding of a range of 5-HT3 receptor agonists and antagonists.
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Affiliation(s)
- Lachlan Munro
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Lucy Kate Ladefoged
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Vithushan Padmanathan
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Signe Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Birgit Schiøtt
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Anders S Kristensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
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115
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Duchemin AL, Vignes H, Vermot J. Mechanically activated piezo channels modulate outflow tract valve development through the Yap1 and Klf2-Notch signaling axis. eLife 2019; 8:44706. [PMID: 31524599 PMCID: PMC6779468 DOI: 10.7554/elife.44706] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 09/14/2019] [Indexed: 12/12/2022] Open
Abstract
Mechanical forces are well known for modulating heart valve developmental programs. Yet, it is still unclear how genetic programs and mechanosensation interact during heart valve development. Here, we assessed the mechanosensitive pathways involved during zebrafish outflow tract (OFT) valve development in vivo. Our results show that the hippo effector Yap1, Klf2, and the Notch signaling pathway are all essential for OFT valve morphogenesis in response to mechanical forces, albeit active in different cell layers. Furthermore, we show that Piezo and TRP mechanosensitive channels are important factors modulating these pathways. In addition, live reporters reveal that Piezo controls Klf2 and Notch activity in the endothelium and Yap1 localization in the smooth muscle progenitors to coordinate OFT valve morphogenesis. Together, this work identifies a unique morphogenetic program during OFT valve formation and places Piezo as a central modulator of the cell response to forces in this process.
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Affiliation(s)
- Anne-Laure Duchemin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Hélène Vignes
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Julien Vermot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, Illkirch, France.,Université de Strasbourg, Illkirch, France
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116
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Abstract
The function of the mammalian heart depends on the interplay between different cardiac cell types. The deployment of these cells, with precise spatiotemporal regulation, is also important during development to establish the heart structure. In this Review, we discuss the diverse origins of cardiac cell types and the lineage relationships between cells of a given type that contribute to different parts of the heart. The emerging lineage tree shows the progression of cell fate diversification, with patterning cues preceding cell type segregation, as well as points of convergence, with overlapping lineages contributing to a given tissue. Several cell lineage markers have been identified. However, caution is required with genetic-tracing experiments in comparison with clonal analyses. Genetic studies on cell populations provided insights into the mechanisms for lineage decisions. In the past 3 years, results of single-cell transcriptomics are beginning to reveal cell heterogeneity and early developmental trajectories. Equating this information with the in vivo location of cells and their lineage history is a current challenge. Characterization of the progenitor cells that form the heart and of the gene regulatory networks that control their deployment is of major importance for understanding the origin of congenital heart malformations and for producing cardiac tissue for use in regenerative medicine.
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117
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Poelmann RE, Gittenberger-de Groot AC. Development and evolution of the metazoan heart. Dev Dyn 2019; 248:634-656. [PMID: 31063648 PMCID: PMC6767493 DOI: 10.1002/dvdy.45] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/25/2019] [Accepted: 04/29/2019] [Indexed: 12/19/2022] Open
Abstract
The mechanisms of the evolution and development of the heart in metazoans are highlighted, starting with the evolutionary origin of the contractile cell, supposedly the precursor of cardiomyocytes. The last eukaryotic common ancestor is likely a combination of several cellular organisms containing their specific metabolic pathways and genetic signaling networks. During evolution, these tool kits diversified. Shared parts of these conserved tool kits act in the development and functioning of pumping hearts and open or closed circulations in such diverse species as arthropods, mollusks, and chordates. The genetic tool kits became more complex by gene duplications, addition of epigenetic modifications, influence of environmental factors, incorporation of viral genomes, cardiac changes necessitated by air‐breathing, and many others. We evaluate mechanisms involved in mollusks in the formation of three separate hearts and in arthropods in the formation of a tubular heart. A tubular heart is also present in embryonic stages of chordates, providing the septated four‐chambered heart, in birds and mammals passing through stages with first and second heart fields. The four‐chambered heart permits the formation of high‐pressure systemic and low‐pressure pulmonary circulation in birds and mammals, allowing for high metabolic rates and maintenance of body temperature. Crocodiles also have a (nearly) separated circulation, but their resting temperature conforms with the environment. We argue that endothermic ancestors lost the capacity to elevate their body temperature during evolution, resulting in ectothermic modern crocodilians. Finally, a clinically relevant paragraph reviews the occurrence of congenital cardiac malformations in humans as derailments of signaling pathways during embryonic development. The cardiac regulatory toolkit contains many factors including epigenetic, genetic, viral, hemodynamic, and environmental factors, but also transcriptional activators, repressors, duplicated genes, redundancies and dose‐dependancies. Numerous toolkits regulate mechanisms including cell‐cell interactions, EMT, mitosis patterns, cell migration and differentiation and left/right sidedness involved in the development of endocardial cushions, looping, septum complexes, pharyngeal arch arteries, chamber and valve formation and conduction system. Evolutionary development of the yolk sac circulation likely preceded the advent of endothermy in amniotes. Parallel evolutionary traits regulate the development of contractile pumps in various taxa often in conjunction with the gut, lungs and excretory organs.
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Affiliation(s)
- Robert E Poelmann
- Institute of Biology, Department of Animal Sciences and Health, Leiden University, Leiden, The Netherlands.,Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
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118
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The role of hemodynamics in bicuspid aortopathy: a histopathologic study. Cardiovasc Pathol 2019; 41:29-37. [PMID: 31029755 DOI: 10.1016/j.carpath.2019.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND A bicuspid aortic valve (BAV) is the most common congenital cardiac malformation and is associated with ascending aortic dilation in 60%-80% of patients. In this study, we aimed to address the role of hemodynamic influences on the development of aortopathy in BAV patients. PATIENT AND METHODS BAV (n=36) and tricuspid aortic valve (TAV) patients (n=17) undergoing aortic valve replacement underwent preoperative flow magnetic resonance imaging (MRI) assessment to detect the area of maximal flow-induced stress in the proximal aorta. Based on these MRI data, paired ascending aortic wall samples [i.e., area of maximal jet impact (jet sample) and the opposite aortic wall (nonjet sample)] were collected during surgery. To study and describe the effects of jet stream on the complete vascular wall, a pathology score was developed based on the recently published aortic consensus paper statement on surgical pathology of the aorta using routine histologic stainings (resorcin fuchsin, hematoxylin-eosin, and Movat) and immunohistochemistry (alpha smooth muscle actin, smooth muscle 22 alpha, platelet endothelial cell adhesion molecule). RESULTS Comparing the jet and nonjet samples in both BAV and TAV, regions of maximal jet impact did not show any difference in the pathology score in the adventitia and the middle and outer media. In the jet samples, the inner media however showed loss of actin expression in both BAV (P<.0001) and the TAV (P=.0074), and the intimal thickness was significantly enlarged in both patient groups (BAV P=.0005, TAV P=.0041), which was not accompanied by loss of elastic lamellae or vascular smooth muscle cell nuclei. CONCLUSIONS In our study population, we could not demonstrate a potential distinct role for hemodynamics in the development of aortopathy in BAV patients even if corrected for aortic diameter, raphe position, or whether the valve is stenotic or regurgitant. The intimal layer and inner media however showed alterations in all jet specimens.
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119
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Aquila I, Frati G, Sciarretta S, Dellegrottaglie S, Torella D, Torella M. New imaging techniques project the cellular and molecular alterations underlying bicuspid aortic valve development. J Mol Cell Cardiol 2019; 129:197-207. [PMID: 30826295 DOI: 10.1016/j.yjmcc.2019.02.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 12/29/2022]
Abstract
Bicuspid aortic valve (BAV) disease is the most common congenital cardiac malformation associated with an increased lifetime risk and a high rate of surgically-relevant valve deterioration and aortic dilatation. Genomic data revealed that different genes are associated with BAV. A dominant genetic factor for the recent past was the basis to the recommendation for a more extensive aortic intervention. However very recent evidence that hemodynamic stressors and alterations of wall shear stress play an important role independent from the genetic trait led to more conservative treatment recommendations. Therefore, there is a current need to improve the ability to risk stratify BAV patients in order to obtain an early detection of valvulopathy and aortopathy while also to predict valve dysfunction and/or aortic disease development. Imaging studies based on new cutting-edge technologies, such us 4-dimensional (4D) flow magnetic resonance imaging (MRI), two-dimensional (2D) or three-dimensional (3D) speckle-tracking imaging (STI) and computation fluid dynamics, combined with studies demonstrating new gene mutations, specific signal pathways alterations, hemodynamic influences, circulating biomarkers modifications, endothelial progenitor cell impairment and immune/inflammatory response, all detected BAV valvulopathy progression and aortic wall abnormality. Overall, the main purpose of this review article is to merge the evidences of imaging and basic science studies in a coherent hypothesis that underlies and thus projects the development of both BAV during embryogenesis and BAV-associated aortopathy and its complications in the adult life, with the final goal to identifying aneurysm formation/rupture susceptibility to improve diagnosis and management of patients with BAV-related aortopathy.
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Affiliation(s)
- Iolanda Aquila
- Molecular and Cellular Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro 88100, Italy
| | - Giacomo Frati
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy; IRCCS NEUROMED, Pozzilli, IS, Italy.
| | - Sebastiano Sciarretta
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy; IRCCS NEUROMED, Pozzilli, IS, Italy
| | - Santo Dellegrottaglie
- Division of Cardiology, Ospedale Accreditato Villa dei Fiori, Acerra, Naples 80011, Italy; The Zena and Michael A. Wiener Cardiovascular Institute, Marie-Josee and Henry R. Kravis Center for Cardiovascular Health, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Daniele Torella
- Molecular and Cellular Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro 88100, Italy.
| | - Michele Torella
- Department of Cardiothoracic Sciences, University of Campania "L. Vanvitelli", Naples, Italy
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120
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Myocardial Notch1-Rbpj deletion does not affect NOTCH signaling, heart development or function. PLoS One 2018; 13:e0203100. [PMID: 30596653 PMCID: PMC6312338 DOI: 10.1371/journal.pone.0203100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 12/11/2018] [Indexed: 01/09/2023] Open
Abstract
During vertebrate cardiac development NOTCH signaling activity in the endocardium is essential for the crosstalk between endocardium and myocardium that initiates ventricular trabeculation and valve primordium formation. This crosstalk leads later to the maturation and compaction of the ventricular chambers and the morphogenesis of the cardiac valves, and its alteration may lead to disease. Although endocardial NOTCH signaling has been shown to be crucial for heart development, its physiological role in the myocardium has not been clearly established. Here we have used mouse genetics to evaluate the role of NOTCH in myocardial development. We have inactivated the unique and ubiquitous NOTCH effector RBPJ in early cardiomyocytes progenitors, and examined its consequences in cardiac development and function. Our results show that mice with Tnnt2-Cre-mediated myocardial-specific deletion of Rbpj develop to term, with homozygous mutant animals showing normal expression of cardiac development markers, and normal adult heart function. Similar observations have been obtained after Notch1 deletion with Tnnt2-Cre. We have also deleted Rbpj in both myocardial and endocardial progenitor cells, using the Nkx2.5-Cre driver, resulting in ventricular septal defect (VSD), double outlet right ventricle (DORV), and bicuspid aortic valve (BAV), due to NOTCH signaling abrogation in the endocardium of cardiac valves. Our data demonstrate that NOTCH-RBPJ inactivation in the myocardium does not affect heart development or adult cardiac function.
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121
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Peterson JC, Chughtai M, Wisse LJ, Gittenberger-de Groot AC, Feng Q, Goumans MJTH, VanMunsteren JC, Jongbloed MRM, DeRuiter MC. Bicuspid aortic valve formation: Nos3 mutation leads to abnormal lineage patterning of neural crest cells and the second heart field. Dis Model Mech 2018; 11:dmm.034637. [PMID: 30242109 PMCID: PMC6215433 DOI: 10.1242/dmm.034637] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 09/05/2018] [Indexed: 12/14/2022] Open
Abstract
The bicuspid aortic valve (BAV), a valve with two instead of three aortic leaflets, belongs to the most prevalent congenital heart diseases in the world, occurring in 0.5-2% of the general population. We aimed to understand how changes in early cellular contributions result in BAV formation and impact cardiovascular outflow tract development. Detailed 3D reconstructions, immunohistochemistry and morphometrics determined that, during valvulogenesis, the non-coronary leaflet separates from the parietal outflow tract cushion instead of originating from an intercalated cushion. Nos3-/- mice develop a BAV without a raphe as a result of incomplete separation of the parietal outflow tract cushion into the right and non-coronary leaflet. Genetic lineage tracing of endothelial, second heart field and neural crest cells revealed altered deposition of neural crest cells and second heart field cells within the parietal outflow tract cushion of Nos3-/- embryos. The abnormal cell lineage distributions also affected the positioning of the aortic and pulmonary valves at the orifice level. The results demonstrate that the development of the right and non-coronary leaflets are closely related. A small deviation in the distribution of neural crest and second heart field populations affects normal valve formation and results in the predominant right-non-type BAV in Nos3-/- mice.
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Affiliation(s)
- Joshua C Peterson
- Dept. Anatomy and Embryology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
| | - Mary Chughtai
- Dept. Anatomy and Embryology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
| | - Lambertus J Wisse
- Dept. Anatomy and Embryology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
| | | | - Qingping Feng
- Dept. Physiology and Pharmacology, Schulich Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Marie-José T H Goumans
- Dept. Molecular Cell Biology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
| | - J Conny VanMunsteren
- Dept. Anatomy and Embryology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
| | - Monique R M Jongbloed
- Dept. Anatomy and Embryology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands.,Dept. Cardiology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
| | - Marco C DeRuiter
- Dept. Anatomy and Embryology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
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