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Welch CL, Aldred MA, Balachandar S, Dooijes D, Eichstaedt CA, Gräf S, Houweling AC, Machado RD, Pandya D, Prapa M, Shaukat M, Southgate L, Tenorio-Castano J, Chung WK. Defining the clinical validity of genes reported to cause pulmonary arterial hypertension. Genet Med 2023; 25:100925. [PMID: 37422716 PMCID: PMC10766870 DOI: 10.1016/j.gim.2023.100925] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 06/26/2023] [Accepted: 06/29/2023] [Indexed: 07/10/2023] Open
Abstract
PURPOSE Pulmonary arterial hypertension (PAH) is a rare, progressive vasculopathy with significant cardiopulmonary morbidity and mortality. Genetic testing is currently recommended for adults diagnosed with heritable, idiopathic, anorexigen-, hereditary hemorrhagic telangiectasia-, and congenital heart disease-associated PAH, PAH with overt features of venous/capillary involvement, and all children diagnosed with PAH. Variants in at least 27 genes have putative evidence for PAH causality. Rigorous assessment of the evidence is needed to inform genetic testing. METHODS An international panel of experts in PAH applied a semi-quantitative scoring system developed by the NIH Clinical Genome Resource to classify the relative strength of evidence supporting PAH gene-disease relationships based on genetic and experimental evidence. RESULTS Twelve genes (BMPR2, ACVRL1, ATP13A3, CAV1, EIF2AK4, ENG, GDF2, KCNK3, KDR, SMAD9, SOX17, and TBX4) were classified as having definitive evidence and 3 genes (ABCC8, GGCX, and TET2) with moderate evidence. Six genes (AQP1, BMP10, FBLN2, KLF2, KLK1, and PDGFD) were classified as having limited evidence for causal effects of variants. TOPBP1 was classified as having no known PAH relationship. Five genes (BMPR1A, BMPR1B, NOTCH3, SMAD1, and SMAD4) were disputed because of a paucity of genetic evidence over time. CONCLUSION We recommend that genetic testing includes all genes with definitive evidence and that caution be taken in the interpretation of variants identified in genes with moderate or limited evidence. Genes with no known evidence for PAH or disputed genes should not be included in genetic testing.
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Affiliation(s)
- Carrie L Welch
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY
| | - Micheala A Aldred
- Division of Pulmonary, Critical Care, Sleep and Occupational Medicine, Indiana University School of Medicine, IN
| | - Srimmitha Balachandar
- Division of Pulmonary, Critical Care, Sleep and Occupational Medicine, Indiana University School of Medicine, IN
| | - Dennis Dooijes
- Department of Genetics, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Christina A Eichstaedt
- Center for Pulmonary Hypertension, Thoraxklinik-Heidelberg gGmbH, at Heidelberg University Hospital and Translational Lung Research Center, German Center for Lung Research, Heidelberg, Germany; Laboratory for Molecular Genetic Diagnostics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Stefan Gräf
- NIHR BioResource for Translational Research - Rare Diseases, Department of Haemotology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom; Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Arjan C Houweling
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Rajiv D Machado
- Molecular and Clinical Sciences Research Institute, St George's University of London, London, United Kingdom
| | - Divya Pandya
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Matina Prapa
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom; St. George's University Hospitals NHS Foundation Trust, London, United Kingdom
| | - Memoona Shaukat
- Center for Pulmonary Hypertension, Thoraxklinik-Heidelberg gGmbH, at Heidelberg University Hospital and Translational Lung Research Center, German Center for Lung Research, Heidelberg, Germany; Laboratory for Molecular Genetic Diagnostics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Laura Southgate
- Molecular and Clinical Sciences Research Institute, St George's University of London, London, United Kingdom
| | - Jair Tenorio-Castano
- Institute of Medical and Molecular Genetics (INGEMM), Hospital Universitario La Paz, IDiPAZ, Universidad Autonoma de Madrid, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain; ITHACA, European Reference Network, Brussels, Belgium
| | - Wendy K Chung
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY; Department of Medicine, Columbia University Irving Medical Center, New York, NY.
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Morales-Paytuví F, Fajardo A, Ruiz-Mirapeix C, Rae J, Tebar F, Bosch M, Enrich C, Collins BM, Parton RG, Pol A. Early proteostasis of caveolins synchronizes trafficking, degradation, and oligomerization to prevent toxic aggregation. J Cell Biol 2023; 222:e202204020. [PMID: 37526691 PMCID: PMC10394380 DOI: 10.1083/jcb.202204020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 04/05/2023] [Accepted: 06/09/2023] [Indexed: 08/02/2023] Open
Abstract
Caveolin-1 (CAV1) and CAV3 are membrane-sculpting proteins driving the formation of the plasma membrane (PM) caveolae. Within the PM mosaic environment, caveola assembly is unique as it requires progressive oligomerization of newly synthesized caveolins while trafficking through the biosynthetic-secretory pathway. Here, we have investigated these early events by combining structural, biochemical, and microscopy studies. We uncover striking trafficking differences between caveolins, with CAV1 rapidly exported to the Golgi and PM while CAV3 is initially retained in the endoplasmic reticulum and laterally moves into lipid droplets. The levels of caveolins in the endoplasmic reticulum are controlled by proteasomal degradation, and only monomeric/low oligomeric caveolins are exported into the cis-Golgi with higher-order oligomers assembling beyond this compartment. When any of those early proteostatic mechanisms are compromised, chemically or genetically, caveolins tend to accumulate along the secretory pathway forming non-functional aggregates, causing organelle damage and triggering cellular stress. Accordingly, we propose a model in which disrupted proteostasis of newly synthesized caveolins contributes to pathogenesis.
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Affiliation(s)
- Frederic Morales-Paytuví
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Alba Fajardo
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Carles Ruiz-Mirapeix
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - James Rae
- Institute for Molecular Bioscience (IMB), The University of Queensland (UQ) , Brisbane, Australia
| | - Francesc Tebar
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Marta Bosch
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Carlos Enrich
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Brett M Collins
- Institute for Molecular Bioscience (IMB), The University of Queensland (UQ) , Brisbane, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience (IMB), The University of Queensland (UQ) , Brisbane, Australia
- Centre for Microscopy and Microanalysis (CMM), The University of Queensland (UQ), Brisbane, Australia
| | - Albert Pol
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA) , Barcelona, Spain
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3
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Kenworthy AK. The building blocks of caveolae revealed: caveolins finally take center stage. Biochem Soc Trans 2023; 51:855-869. [PMID: 37082988 DOI: 10.1042/bst20221298] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/07/2023] [Accepted: 04/14/2023] [Indexed: 04/22/2023]
Abstract
The ability of cells to divide, migrate, relay signals, sense mechanical stimuli, and respond to stress all rely on nanoscale invaginations of the plasma membrane known as caveolae. The caveolins, a family of monotopic membrane proteins, form the inner layer of the caveolar coat. Caveolins have long been implicated in the generation of membrane curvature, in addition to serving as scaffolds for signaling proteins. Until recently, however, the molecular architecture of caveolins was unknown, making it impossible to understand how they operate at a mechanistic level. Over the past year, two independent lines of evidence - experimental and computational - have now converged to provide the first-ever glimpse into the structure of the oligomeric caveolin complexes that function as the building blocks of caveolae. Here, we summarize how these discoveries are transforming our understanding of this long-enigmatic protein family and their role in caveolae assembly and function. We present new models inspired by the structure for how caveolins oligomerize, remodel membranes, interact with their binding partners, and reorganize when mutated. Finally, we discuss emerging insights into structural differences among caveolin family members that enable them to support the proper functions of diverse tissues and organisms.
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Affiliation(s)
- Anne K Kenworthy
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, U.S.A
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, U.S.A
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Han B, Gulsevin A, Connolly S, Wang T, Meyer B, Porta J, Tiwari A, Deng A, Chang L, Peskova Y, Mchaourab HS, Karakas E, Ohi MD, Meiler J, Kenworthy AK. Structural analysis of the P132L disease mutation in caveolin-1 reveals its role in the assembly of oligomeric complexes. J Biol Chem 2023; 299:104574. [PMID: 36870682 PMCID: PMC10124911 DOI: 10.1016/j.jbc.2023.104574] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 01/09/2023] [Accepted: 02/03/2023] [Indexed: 03/06/2023] Open
Abstract
Caveolin-1 (CAV1) is a membrane-sculpting protein that oligomerizes to generate flask-shaped invaginations of the plasma membrane known as caveolae. Mutations in CAV1 have been linked to multiple diseases in humans. Such mutations often interfere with oligomerization and the intracellular trafficking processes required for successful caveolae assembly, but the molecular mechanisms underlying these defects have not been structurally explained. Here, we investigate how a disease-associated mutation in one of the most highly conserved residues in CAV1, P132L, affects CAV1 structure and oligomerization. We show that P132 is positioned at a major site of protomer-protomer interactions within the CAV1 complex, providing a structural explanation for why the mutant protein fails to homo-oligomerize correctly. Using a combination of computational, structural, biochemical, and cell biological approaches, we find that despite its homo-oligomerization defects P132L is capable of forming mixed hetero-oligomeric complexes with WT CAV1 and that these complexes can be incorporated into caveolae. These findings provide insights into the fundamental mechanisms that control the formation of homo- and hetero-oligomers of caveolins that are essential for caveolae biogenesis, as well as how these processes are disrupted in human disease.
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Affiliation(s)
- Bing Han
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Alican Gulsevin
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Sarah Connolly
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Ting Wang
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Brigitte Meyer
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jason Porta
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Ajit Tiwari
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Angie Deng
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Louise Chang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Yelena Peskova
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Erkan Karakas
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA; Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA; Institute for Drug Discovery, Leipzig University, Leipzig, Germany
| | - Anne K Kenworthy
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA.
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5
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Sotodosos-Alonso L, Pulgarín-Alfaro M, Del Pozo MA. Caveolae Mechanotransduction at the Interface between Cytoskeleton and Extracellular Matrix. Cells 2023; 12:cells12060942. [PMID: 36980283 PMCID: PMC10047380 DOI: 10.3390/cells12060942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/30/2023] Open
Abstract
The plasma membrane (PM) is subjected to multiple mechanical forces, and it must adapt and respond to them. PM invaginations named caveolae, with a specific protein and lipid composition, play a crucial role in this mechanosensing and mechanotransduction process. They respond to PM tension changes by flattening, contributing to the buffering of high-range increases in mechanical tension, while novel structures termed dolines, sharing Caveolin1 as the main component, gradually respond to low and medium forces. Caveolae are associated with different types of cytoskeletal filaments, which regulate membrane tension and also initiate multiple mechanotransduction pathways. Caveolar components sense the mechanical properties of the substrate and orchestrate responses that modify the extracellular matrix (ECM) according to these stimuli. They perform this function through both physical remodeling of ECM, where the actin cytoskeleton is a central player, and via the chemical alteration of the ECM composition by exosome deposition. Here, we review mechanotransduction regulation mediated by caveolae and caveolar components, focusing on how mechanical cues are transmitted through the cellular cytoskeleton and how caveolae respond and remodel the ECM.
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Affiliation(s)
- Laura Sotodosos-Alonso
- Mechanoadaptation and Caveolae Biology Laboratory, Novel Mechanisms of Atherosclerosis Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
| | - Marta Pulgarín-Alfaro
- Mechanoadaptation and Caveolae Biology Laboratory, Novel Mechanisms of Atherosclerosis Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
| | - Miguel A Del Pozo
- Mechanoadaptation and Caveolae Biology Laboratory, Novel Mechanisms of Atherosclerosis Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
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6
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Dai L, Du L. Genes in pediatric pulmonary arterial hypertension and the most promising BMPR2 gene therapy. Front Genet 2022; 13:961848. [PMID: 36506323 PMCID: PMC9730536 DOI: 10.3389/fgene.2022.961848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 11/03/2022] [Indexed: 11/25/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a rare but progressive and lethal vascular disease of diverse etiologies, mainly caused by proliferation of endothelial cells, smooth muscle cells in the pulmonary artery, and fibroblasts, which ultimately leads to right-heart hypertrophy and cardiac failure. Recent genetic studies of childhood-onset PAH report that there is a greater genetic burden in children than in adults. Since the first-identified pathogenic gene of PAH, BMPR2, which encodes bone morphogenetic protein receptor 2, a receptor in the transforming growth factor-β superfamily, was discovered, novel causal genes have been identified and substantially sharpened our insights into the molecular genetics of childhood-onset PAH. Currently, some newly identified deleterious genetic variants in additional genes implicated in childhood-onset PAH, such as potassium channels (KCNK3) and transcription factors (TBX4 and SOX17), have been reported and have greatly updated our understanding of the disease mechanism. In this review, we summarized and discussed the advances of genetic variants underlying childhood-onset PAH susceptibility and potential mechanism, and the most promising BMPR2 gene therapy and gene delivery approaches to treat childhood-onset PAH in the future.
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7
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Porta JC, Han B, Gulsevin A, Chung JM, Peskova Y, Connolly S, Mchaourab HS, Meiler J, Karakas E, Kenworthy AK, Ohi MD. Molecular architecture of the human caveolin-1 complex. Sci Adv 2022; 8:eabn7232. [PMID: 35544577 PMCID: PMC9094659 DOI: 10.1126/sciadv.abn7232] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Membrane-sculpting proteins shape the morphology of cell membranes and facilitate remodeling in response to physiological and environmental cues. Complexes of the monotopic membrane protein caveolin function as essential curvature-generating components of caveolae, flask-shaped invaginations that sense and respond to plasma membrane tension. However, the structural basis for caveolin's membrane remodeling activity is currently unknown. Here, we show that, using cryo-electron microscopy, the human caveolin-1 complex is composed of 11 protomers organized into a tightly packed disc with a flat membrane-embedded surface. The structural insights suggest a previously unrecognized mechanism for how membrane-sculpting proteins interact with membranes and reveal how key regions of caveolin-1, including its scaffolding, oligomerization, and intramembrane domains, contribute to its function.
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Affiliation(s)
- Jason C. Porta
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Bing Han
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Alican Gulsevin
- Department of Chemistry, Vanderbilt University Nashville, TN, USA
| | - Jeong Min Chung
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biotechnology, The Catholic University of Korea, Bucheon, Republic of Korea
| | - Yelena Peskova
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Sarah Connolly
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Hassane S. Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University Nashville, TN, USA
- Institute for Drug Discovery, Leipzig University, Germany
| | - Erkan Karakas
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
- Corresponding author. (E.K.); (A.K.K.); (M.D.O.)
| | - Anne K. Kenworthy
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
- Corresponding author. (E.K.); (A.K.K.); (M.D.O.)
| | - Melanie D. Ohi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI, USA
- Corresponding author. (E.K.); (A.K.K.); (M.D.O.)
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Andre P, Joshi SR, Briscoe SD, Alexander MJ, Li G, Kumar R. Therapeutic Approaches for Treating Pulmonary Arterial Hypertension by Correcting Imbalanced TGF-β Superfamily Signaling. Front Med (Lausanne) 2022; 8:814222. [PMID: 35141256 PMCID: PMC8818880 DOI: 10.3389/fmed.2021.814222] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/15/2021] [Indexed: 12/19/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a rare disease characterized by high blood pressure in the pulmonary circulation driven by pathological remodeling of distal pulmonary arteries, leading typically to death by right ventricular failure. Available treatments improve physical activity and slow disease progression, but they act primarily as vasodilators and have limited effects on the biological cause of the disease—the uncontrolled proliferation of vascular endothelial and smooth muscle cells. Imbalanced signaling by the transforming growth factor-β (TGF-β) superfamily contributes extensively to dysregulated vascular cell proliferation in PAH, with overactive pro-proliferative SMAD2/3 signaling occurring alongside deficient anti-proliferative SMAD1/5/8 signaling. We review the TGF-β superfamily mechanisms underlying PAH pathogenesis, superfamily interactions with inflammation and mechanobiological forces, and therapeutic strategies under development that aim to restore SMAD signaling balance in the diseased pulmonary arterial vessels. These strategies could potentially reverse pulmonary arterial remodeling in PAH by targeting causative mechanisms and therefore hold significant promise for the PAH patient population.
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Abstract
Pulmonary hypertension (PH) is a rare disease with a high morbidity and mortality rate. A number of systemic diseases and genetic mutations are known to lead to PH. The main features of PH are altered vascular relaxation responses and the activation of proliferative and anti-apoptotic pathways, resulting in pulmonary vascular remodeling, elevated pulmonary artery pressure, and right ventricular hypertrophy, ultimately leading to right heart failure and premature death. Important advances have been made in the field of pulmonary pathobiology, and several deregulated signaling pathways have been shown to be associated with PH. Clinical and experimental studies suggest that, irrespective of the underlying disease, endothelial cell disruption and/or dysfunction play a key role in the pathogenesis of PH. Endothelial caveolin-1, a cell membrane protein, interacts with and regulates several transcription factors and maintains homeostasis. Disruption of endothelial cells leads to the loss or dysfunction of endothelial caveolin-1, resulting in reciprocal activation of proliferative and inflammatory pathways, leading to cell proliferation, medial hypertrophy, and PH, which initiates PH and facilitates its progression. The disruption of endothelial cells, accompanied by the loss of endothelial caveolin-1, is accompanied by enhanced expression of caveolin-1 in smooth muscle cells (SMCs) that leads to pro-proliferative and pro-migratory responses, subsequently leading to neointima formation. The neointimal cells have low caveolin-1 and normal eNOS expression that may be responsible for promoting nitrosative and oxidative stress, furthering cell proliferation and metabolic alterations. These changes have been observed in human PH lungs and in experimental models of PH. In hypoxia-induced PH, there is no endothelial disruption, loss of endothelial caveolin-1, or enhanced expression of caveolin-1 in SMCs. Hypoxia induces alterations in membrane composition without caveolin-1 or any other membrane protein loss. However, caveolin-1 is dysfunctional, resulting in cell proliferation, medial hypertrophy, and PH. These alterations are reversible upon removal of hypoxia, provided there is no associated EC disruption. This review examined the role of caveolin-1 disruption and dysfunction in PH.
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Affiliation(s)
- Rajamma Mathew
- Section of Pediatric Cardiology, Departments of Pediatrics and Physiology, New York Medical College, Valhalla, NY 10595, USA
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10
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González-Hódar L, McDonald JG, Vale G, Thompson BM, Figueroa AM, Tapia PJ, Robledo F, Agarwal AK, Garg A, Horton JD, Cortés V. Decreased caveolae in AGPAT2 lacking adipocytes is independent of changes in cholesterol or sphingolipid levels: A whole cell and plasma membrane lipidomic analysis of adipogenesis. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166167. [PMID: 33989739 DOI: 10.1016/j.bbadis.2021.166167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/19/2021] [Accepted: 05/04/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Adipocytes from lipodystrophic Agpat2-/- mice have impaired adipogenesis and fewer caveolae. Herein, we examined whether these defects are associated with changes in lipid composition or abnormal levels of caveolae-associated proteins. Lipidome changes were quantified in differentiated Agpat2-/- adipocytes to identify lipids with potential adipogenic roles. METHODS Agpat2-/- and wild type brown preadipocytes were differentiated in vitro. Plasma membrane was purified by ultracentrifugation. Number of caveolae and caveolae-associated proteins, as well as sterol, sphingolipid, and phospholipid lipidome were determined across differentiation. RESULTS Differentiated Agpat2-/- adipocytes had decreased caveolae number but conserved insulin signaling. Caveolin-1 and cavin-1 levels were equivalent between Agpat2-/- and wild type adipocytes. No differences in PM cholesterol and sphingolipids abundance were detected between genotypes. Levels of phosphatidylserine at day 10 of differentiation were increased in Agpat2-/- adipocytes. Wild type adipocytes had increased whole cell triglyceride, diacylglycerol, phosphatidylglycerol, phosphatidic acid, lysophosphatidylcholine, lysophosphatidylethanolamine, and trihexosyl ceramide, and decreased 24,25-dihydrolanosterol and sitosterol, as a result of adipogenic differentiation. By contrast, adipogenesis did not modify whole cell neutral lipids but increased lysophosphatidylcholine, sphingomyelin, and trihexosyl ceramide levels in Agpat2-/- adipocytes. Unexpectedly, adipogenesis decreased PM levels of main phospholipids in both genotypes. CONCLUSION In Agpat2-/- adipocytes, decreased caveolae is not associated with changes in PM cholesterol nor sphingolipid levels; however, increased PM phosphatidylserine content may be implicated. Abnormal lipid composition is associated with the adipogenic abnormalities of Agpat2 -/- adipocytes but does not prevent insulin signaling.
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Affiliation(s)
- Lila González-Hódar
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, 8331150, Chile
| | - Jeffrey G McDonald
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States; Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, United States
| | - Goncalo Vale
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
| | - Bonne M Thompson
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
| | - Ana-María Figueroa
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, 8331150, Chile
| | - Pablo J Tapia
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, 8331150, Chile
| | - Fermín Robledo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, 8331150, Chile
| | - Anil K Agarwal
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, TX 75390, United States
| | - Abhimanyu Garg
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, TX 75390, United States
| | - Jay D Horton
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States; Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, United States; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, United States.
| | - Víctor Cortés
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, 8331150, Chile.
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11
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Zhu N, Swietlik EM, Welch CL, Pauciulo MW, Hagen JJ, Zhou X, Guo Y, Karten J, Pandya D, Tilly T, Lutz KA, Martin JM, Treacy CM, Rosenzweig EB, Krishnan U, Coleman AW, Gonzaga-Jauregui C, Lawrie A, Trembath RC, Wilkins MR, Morrell NW, Shen Y, Gräf S, Nichols WC, Chung WK. Rare variant analysis of 4241 pulmonary arterial hypertension cases from an international consortium implicates FBLN2, PDGFD, and rare de novo variants in PAH. Genome Med 2021; 13:80. [PMID: 33971972 PMCID: PMC8112021 DOI: 10.1186/s13073-021-00891-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 04/19/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Pulmonary arterial hypertension (PAH) is a lethal vasculopathy characterized by pathogenic remodeling of pulmonary arterioles leading to increased pulmonary pressures, right ventricular hypertrophy, and heart failure. PAH can be associated with other diseases (APAH: connective tissue diseases, congenital heart disease, and others) but often the etiology is idiopathic (IPAH). Mutations in bone morphogenetic protein receptor 2 (BMPR2) are the cause of most heritable cases but the vast majority of other cases are genetically undefined. METHODS To identify new risk genes, we utilized an international consortium of 4241 PAH cases with exome or genome sequencing data from the National Biological Sample and Data Repository for PAH, Columbia University Irving Medical Center, and the UK NIHR BioResource - Rare Diseases Study. The strength of this combined cohort is a doubling of the number of IPAH cases compared to either national cohort alone. We identified protein-coding variants and performed rare variant association analyses in unrelated participants of European ancestry, including 1647 IPAH cases and 18,819 controls. We also analyzed de novo variants in 124 pediatric trios enriched for IPAH and APAH-CHD. RESULTS Seven genes with rare deleterious variants were associated with IPAH with false discovery rate smaller than 0.1: three known genes (BMPR2, GDF2, and TBX4), two recently identified candidate genes (SOX17, KDR), and two new candidate genes (fibulin 2, FBLN2; platelet-derived growth factor D, PDGFD). The new genes were identified based solely on rare deleterious missense variants, a variant type that could not be adequately assessed in either cohort alone. The candidate genes exhibit expression patterns in lung and heart similar to that of known PAH risk genes, and most variants occur in conserved protein domains. For pediatric PAH, predicted deleterious de novo variants exhibited a significant burden compared to the background mutation rate (2.45×, p = 2.5e-5). At least eight novel pediatric candidate genes carrying de novo variants have plausible roles in lung/heart development. CONCLUSIONS Rare variant analysis of a large international consortium identified two new candidate genes-FBLN2 and PDGFD. The new genes have known functions in vasculogenesis and remodeling. Trio analysis predicted that ~ 15% of pediatric IPAH may be explained by de novo variants.
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Affiliation(s)
- Na Zhu
- Department of Pediatrics, Columbia University Irving Medical Center, 1150 St. Nicholas Avenue, Room 620, New York, NY, 10032, USA
- Department of Systems Biology, Columbia University, New York, NY, USA
| | - Emilia M Swietlik
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Carrie L Welch
- Department of Pediatrics, Columbia University Irving Medical Center, 1150 St. Nicholas Avenue, Room 620, New York, NY, 10032, USA
| | - Michael W Pauciulo
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jacob J Hagen
- Department of Pediatrics, Columbia University Irving Medical Center, 1150 St. Nicholas Avenue, Room 620, New York, NY, 10032, USA
- Department of Systems Biology, Columbia University, New York, NY, USA
| | - Xueya Zhou
- Department of Pediatrics, Columbia University Irving Medical Center, 1150 St. Nicholas Avenue, Room 620, New York, NY, 10032, USA
- Department of Systems Biology, Columbia University, New York, NY, USA
| | - Yicheng Guo
- Department of Systems Biology, Columbia University, New York, NY, USA
| | | | - Divya Pandya
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Tobias Tilly
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Katie A Lutz
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jennifer M Martin
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource for Translational Research, Cambridge Biomedical Campus, Cambridge, UK
| | - Carmen M Treacy
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Erika B Rosenzweig
- Department of Pediatrics, Columbia University Irving Medical Center, 1150 St. Nicholas Avenue, Room 620, New York, NY, 10032, USA
| | - Usha Krishnan
- Department of Pediatrics, Columbia University Irving Medical Center, 1150 St. Nicholas Avenue, Room 620, New York, NY, 10032, USA
| | - Anna W Coleman
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | | | - Allan Lawrie
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Richard C Trembath
- Department of Medical and Molecular Genetics, King's College London, London, UK
| | - Martin R Wilkins
- National Heart & Lung Institute, Imperial College London, London, UK
| | | | | | | | | | - Nicholas W Morrell
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource for Translational Research, Cambridge Biomedical Campus, Cambridge, UK
- Addenbrooke's Hospital NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
- Royal Papworth Hospital NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK
| | - Yufeng Shen
- Department of Systems Biology, Columbia University, New York, NY, USA
- Department of Biomedical Informatics, Columbia University, New York, NY, USA
| | - Stefan Gräf
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource for Translational Research, Cambridge Biomedical Campus, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - William C Nichols
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Wendy K Chung
- Department of Pediatrics, Columbia University Irving Medical Center, 1150 St. Nicholas Avenue, Room 620, New York, NY, 10032, USA.
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA.
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12
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Gairhe S, Awad KS, Dougherty EJ, Ferreyra GA, Wang S, Yu ZX, Takeda K, Demirkale CY, Torabi-Parizi P, Austin ED, Elinoff JM, Danner RL. Type I interferon activation and endothelial dysfunction in caveolin-1 insufficiency-associated pulmonary arterial hypertension. Proc Natl Acad Sci U S A 2021; 118:e2010206118. [PMID: 33836561 DOI: 10.1073/pnas.2010206118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interferonopathies, interferon (IFN)-α/β therapy, and caveolin-1 (CAV1) loss-of-function have all been associated with pulmonary arterial hypertension (PAH). Here, CAV1-silenced primary human pulmonary artery endothelial cells (PAECs) were proliferative and hypermigratory, with reduced cytoskeletal stress fibers. Signal transducers and activators of transcription (STAT) and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) were both constitutively activated in these cells, resulting in a type I IFN-biased inflammatory signature. Cav1 -/- mice that spontaneously develop pulmonary hypertension were found to have STAT1 and AKT activation in lung homogenates and increased circulating levels of CXCL10, a hallmark of IFN-mediated inflammation. PAH patients with CAV1 mutations also had elevated serum CXCL10 levels and their fibroblasts mirrored phenotypic and molecular features of CAV1-deficient PAECs. Moreover, immunofluorescence staining revealed endothelial CAV1 loss and STAT1 activation in the pulmonary arterioles of patients with idiopathic PAH, suggesting that this paradigm might not be limited to rare CAV1 frameshift mutations. While blocking JAK/STAT or AKT rescued aspects of CAV1 loss, only AKT inhibitors suppressed activation of both signaling pathways simultaneously. Silencing endothelial nitric oxide synthase (NOS3) prevented STAT1 and AKT activation induced by CAV1 loss, implicating CAV1/NOS3 uncoupling and NOS3 dysregulation in the inflammatory phenotype. Exogenous IFN reduced CAV1 expression, activated STAT1 and AKT, and altered the cytoskeleton of PAECs, implicating these mechanisms in PAH associated with autoimmune and autoinflammatory diseases, as well as IFN therapy. CAV1 insufficiency elicits an IFN inflammatory response that results in a dysfunctional endothelial cell phenotype and targeting this pathway may reduce pathologic vascular remodeling in PAH.
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13
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Parton RG, Tillu V, McMahon KA, Collins BM. Key phases in the formation of caveolae. Curr Opin Cell Biol 2021; 71:7-14. [PMID: 33677149 DOI: 10.1016/j.ceb.2021.01.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/28/2021] [Accepted: 01/30/2021] [Indexed: 12/20/2022]
Abstract
Caveolae are abundant plasma membrane pits formed by the coordinated action of peripheral and integral membrane proteins and membrane lipids. Here, we discuss recent studies that are starting to provide a glimpse of how filamentous cavin proteins, membrane-embedded caveolin proteins, and specific plasma membrane lipids are brought together to make the unique caveola surface domain. Protein assembly involves multiple low-affinity interactions that are dependent on 'fuzzy' charge-dependent interactions mediated in part by disordered cavin and caveolin domains. We propose that cavins help generate a lipid domain conducive to full insertion of caveolin into the bilayer to promote caveola formation. The synergistic assembly of these dynamic protein complexes supports the formation of a metastable membrane domain that can be readily disassembled both in response to cellular stress and during endocytic trafficking. We present a mechanistic model for generation of caveolae based on these new insights.
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Affiliation(s)
- Robert G Parton
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, 4072, Australia; The University of Queensland, Centre for Microscopy and Microanalysis, Brisbane, Queensland, 4072, Australia.
| | - Vikas Tillu
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, 4072, Australia
| | - Kerrie-Ann McMahon
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, 4072, Australia
| | - Brett M Collins
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, 4072, Australia.
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14
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Han B, Porta JC, Hanks JL, Peskova Y, Binshtein E, Dryden K, Claxton DP, Mchaourab HS, Karakas E, Ohi MD, Kenworthy AK. Structure and assembly of CAV1 8S complexes revealed by single particle electron microscopy. Sci Adv 2020; 6:6/49/eabc6185. [PMID: 33268374 PMCID: PMC7821874 DOI: 10.1126/sciadv.abc6185] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 10/16/2020] [Indexed: 05/21/2023]
Abstract
Highly stable oligomeric complexes of the monotopic membrane protein caveolin serve as fundamental building blocks of caveolae. Current evidence suggests these complexes are disc shaped, but the details of their structural organization and how they assemble are poorly understood. Here, we address these questions using single particle electron microscopy of negatively stained recombinant 8S complexes of human caveolin 1. We show that 8S complexes are toroidal structures ~15 nm in diameter that consist of an outer ring, an inner ring, and central protruding stalk. Moreover, we map the position of the N and C termini and determine their role in complex assembly, and visualize the 8S complexes in heterologous caveolae. Our findings provide critical insights into the structural features of 8S complexes and allow us to propose a model for how these highly stable membrane-embedded complexes are generated.
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Affiliation(s)
- Bing Han
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jason C Porta
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Jessica L Hanks
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Yelena Peskova
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Elad Binshtein
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Kelly Dryden
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Derek P Claxton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Erkan Karakas
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Anne K Kenworthy
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA.
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
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15
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Swietlik EM, Prapa M, Martin JM, Pandya D, Auckland K, Morrell NW, Gräf S. 'There and Back Again'-Forward Genetics and Reverse Phenotyping in Pulmonary Arterial Hypertension. Genes (Basel) 2020; 11:E1408. [PMID: 33256119 PMCID: PMC7760524 DOI: 10.3390/genes11121408] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/17/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023] Open
Abstract
Although the invention of right heart catheterisation in the 1950s enabled accurate clinical diagnosis of pulmonary arterial hypertension (PAH), it was not until 2000 when the landmark discovery of the causative role of bone morphogenetic protein receptor type II (BMPR2) mutations shed new light on the pathogenesis of PAH. Since then several genes have been discovered, which now account for around 25% of cases with the clinical diagnosis of idiopathic PAH. Despite the ongoing efforts, in the majority of patients the cause of the disease remains elusive, a phenomenon often referred to as "missing heritability". In this review, we discuss research approaches to uncover the genetic architecture of PAH starting with forward phenotyping, which in a research setting should focus on stable intermediate phenotypes, forward and reverse genetics, and finally reverse phenotyping. We then discuss potential sources of "missing heritability" and how functional genomics and multi-omics methods are employed to tackle this problem.
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Affiliation(s)
- Emilia M. Swietlik
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK; (E.M.S.); (M.P.); (J.M.M.); (D.P.); (K.A.); (N.W.M.)
- Royal Papworth Hospital NHS Foundation Trust, Cambridge CB2 0AY, UK
- Addenbrooke’s Hospital NHS Foundation Trust, Cambridge CB2 0QQ, UK
| | - Matina Prapa
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK; (E.M.S.); (M.P.); (J.M.M.); (D.P.); (K.A.); (N.W.M.)
- Addenbrooke’s Hospital NHS Foundation Trust, Cambridge CB2 0QQ, UK
| | - Jennifer M. Martin
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK; (E.M.S.); (M.P.); (J.M.M.); (D.P.); (K.A.); (N.W.M.)
| | - Divya Pandya
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK; (E.M.S.); (M.P.); (J.M.M.); (D.P.); (K.A.); (N.W.M.)
| | - Kathryn Auckland
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK; (E.M.S.); (M.P.); (J.M.M.); (D.P.); (K.A.); (N.W.M.)
| | - Nicholas W. Morrell
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK; (E.M.S.); (M.P.); (J.M.M.); (D.P.); (K.A.); (N.W.M.)
- Royal Papworth Hospital NHS Foundation Trust, Cambridge CB2 0AY, UK
- Addenbrooke’s Hospital NHS Foundation Trust, Cambridge CB2 0QQ, UK
- NIHR BioResource for Translational Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - Stefan Gräf
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK; (E.M.S.); (M.P.); (J.M.M.); (D.P.); (K.A.); (N.W.M.)
- NIHR BioResource for Translational Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0PT, UK
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16
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Buwa N, Mazumdar D, Balasubramanian N. Caveolin1 Tyrosine-14 Phosphorylation: Role in Cellular Responsiveness to Mechanical Cues. J Membr Biol 2020; 253:509-534. [PMID: 33089394 DOI: 10.1007/s00232-020-00143-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/05/2020] [Indexed: 02/07/2023]
Abstract
The plasma membrane is a dynamic lipid bilayer that engages with the extracellular microenvironment and intracellular cytoskeleton. Caveolae are distinct plasma membrane invaginations lined by integral membrane proteins Caveolin1, 2, and 3. Caveolae formation and stability is further supported by additional proteins including Cavin1, EHD2, Pacsin2 and ROR1. The lipid composition of caveolar membranes, rich in cholesterol and phosphatidylserine, actively contributes to caveolae formation and function. Post-translational modifications of Cav1, including its phosphorylation of the tyrosine-14 residue (pY14Cav1) are vital to its function in and out of caveolae. Cells that experience significant mechanical stress are seen to have abundant caveolae. They play a vital role in regulating cellular signaling and endocytosis, which could further affect the abundance and distribution of caveolae at the PM, contributing to sensing and/or buffering mechanical stress. Changes in membrane tension in cells responding to multiple mechanical stimuli affects the organization and function of caveolae. These mechanical cues regulate pY14Cav1 levels and function in caveolae and focal adhesions. This review, along with looking at the mechanosensitive nature of caveolae, focuses on the role of pY14Cav1 in regulating cellular mechanotransduction.
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Affiliation(s)
- Natasha Buwa
- Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Debasmita Mazumdar
- Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Nagaraj Balasubramanian
- Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.
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17
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Rathinasabapathy A, Copeland C, Crabtree A, Carrier EJ, Moore C, Shay S, Gladson S, Austin ED, Kenworthy AK, Loyd JE, Hemnes AR, West JD. Expression of a Human Caveolin-1 Mutation in Mice Drives Inflammatory and Metabolic Defect-Associated Pulmonary Arterial Hypertension. Front Med (Lausanne) 2020; 7:540. [PMID: 33015095 PMCID: PMC7516012 DOI: 10.3389/fmed.2020.00540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/30/2020] [Indexed: 12/20/2022] Open
Abstract
Background: In 2012, mutations in Cav1 were found to be the driving mutation in several cases of heritable pulmonary arterial hypertension (PAH). These mutations replaced the last 21 amino acids of Cav1 with a novel 22-amino-acid sequence. Because previously only Cav1 knockouts had been studied in the context of PAH, examining the in vivo effects of this novel mutation holds promise for new understanding of the role of Cav1 in disease etiology. Methods: The new 22 amino acids created by the human mutation were knocked into the native mouse Cav1 locus. The mice underwent hemodynamic, energy balance, and inflammatory measurements, both at baseline and after being stressed with either a metabolic or an inflammatory challenge [low-dose lipopolysaccharide (LPS)]. To metabolically challenge the mice, they were injected with streptozotocin (STZ) and fed a high-fat diet for 12 weeks. Results: Very little mutant protein was found in vivo (roughly 2% of wild-type by mass spectrometry), probably because of degradation after failure to traffic from the endoplasmic reticulum. The homozygous mutants developed a mild, low-penetrance PAH similar to that described previously in knockouts, and neither baseline nor metabolic nor inflammatory stress resulted in pressures above normal in heterozygous animals. The homozygous mutants had increased lean mass and worsened oral glucose tolerance, as previously described in knockouts. Novel findings include the preservation of Cav2 and accessory proteins in the liver and the kidney, while they are lost with homozygous Cav1 mutation in the lungs. We also found that the homozygous mutants had a significantly lower tolerance to voluntary spontaneous exercise than the wild-type mice, with the heterozygous mice at an intermediate level. The mutants also had higher circulating monocytes, with both heterozygous and homozygous animals having higher pulmonary MCP1 and MCP5 proteins. The heterozygous animals also lost weight at an LPS challenge level at which the wild-type mice continued to gain weight. Conclusions: The Cav1 mutation identified in human patients in 2012 is molecularly similar to a knockout of Cav1. It results in not only metabolic deficiencies and mild pulmonary hypertension, as expected, but also an inflammatory phenotype and reduced spontaneous exercise.
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Affiliation(s)
| | - Courtney Copeland
- Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
| | - Amber Crabtree
- Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Erica J Carrier
- Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Christy Moore
- Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Sheila Shay
- Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Santhi Gladson
- Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Eric D Austin
- Pediatrics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Anne K Kenworthy
- Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - James E Loyd
- Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Anna R Hemnes
- Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - James D West
- Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
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18
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Abstract
ABSTRACT
Caveolae are invaginations of the plasma membrane that are remarkably abundant in adipocytes, endothelial cells and muscle. Caveolae provide cells with resources for mechanoprotection, can undergo fission from the plasma membrane and can regulate a variety of signaling pathways. Caveolins are fundamental components of caveolae, but many cells, such as hepatocytes and many neurons, express caveolins without forming distinguishable caveolae. Thus, the function of caveolins goes beyond their roles as caveolar components. The membrane-organizing and -sculpting capacities of caveolins, in combination with their complex intracellular trafficking, might contribute to these additional roles. Furthermore, non-caveolar caveolins can potentially interact with proteins normally excluded from caveolae. Here, we revisit the non-canonical roles of caveolins in a variety of cellular contexts including liver, brain, lymphocytes, cilia and cancer cells, as well as consider insights from invertebrate systems. Non-caveolar caveolins can determine the intracellular fluxes of active lipids, including cholesterol and sphingolipids. Accordingly, caveolins directly or remotely control a plethora of lipid-dependent processes such as the endocytosis of specific cargoes, sorting and transport in endocytic compartments, or different signaling pathways. Indeed, loss-of-function of non-caveolar caveolins might contribute to the common phenotypes and pathologies of caveolin-deficient cells and animals.
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Affiliation(s)
- Albert Pol
- Cell Compartments and Signaling Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, 08036, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010, Barcelona, Spain
| | - Frederic Morales-Paytuví
- Cell Compartments and Signaling Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain
| | - Marta Bosch
- Cell Compartments and Signaling Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, 08036, Barcelona, Spain
- Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, 08036, Barcelona, Spain
| | - Robert G. Parton
- Institute for Molecular Bioscience (IMB), The University of Queensland (UQ), Brisbane, Queensland 4072, Australia
- Centre for Microscopy and Microanalysis (CMM) IMB, The University of Queensland (UQ), Brisbane, Queensland 4072, Australia
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19
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Affiliation(s)
- Emilia M Swietlik
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom.,Addenbrooke's Hospital NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom.,Royal Papworth Hospital NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Stefan Gräf
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom.,Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom.,NIHR BioResource for Translational Research, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Nicholas W Morrell
- Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom.,Addenbrooke's Hospital NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom.,Royal Papworth Hospital NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom.,NIHR BioResource for Translational Research, Cambridge Biomedical Campus, Cambridge, United Kingdom
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20
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Abstract
Pulmonary arterial hypertension (PAH) is a rare, progressive disorder typified by occlusion of the pulmonary arterioles owing to endothelial dysfunction and uncontrolled proliferation of pulmonary artery smooth muscle cells and fibroblasts. Vascular occlusion can lead to increased pressure in the pulmonary arteries, often resulting in right ventricular failure with shortness of breath and syncope. Since the identification of BMPR2, which encodes a receptor in the transforming growth factor-β superfamily, the development of high-throughput sequencing approaches to identify novel causal genes has substantially advanced our understanding of the molecular genetics of PAH. In the past 6 years, additional pathways involved in PAH susceptibility have been described through the identification of deleterious genetic variants in potassium channels (KCNK3 and ABCC8) and transcription factors (TBX4 and SOX17), among others. Although familial PAH most often has an autosomal-dominant pattern of inheritance, cases of incomplete penetrance and evidence of genetic heterogeneity support a model of PAH as a Mendelian disorder with complex disease features. In this Review, we outline the latest advances in the detection of rare and common genetic variants underlying PAH susceptibility and disease progression. These findings have clinical implications for lung vascular function and can help to identify mechanistic pathways amenable to pharmacological intervention.
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Affiliation(s)
- Laura Southgate
- Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK.,Department of Medical and Molecular Genetics, King's College London, London, UK
| | - Rajiv D Machado
- Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Stefan Gräf
- Department of Medicine, University of Cambridge, Cambridge, UK.,Department of Haematology, University of Cambridge, Cambridge, UK.,NIHR BioResource, Cambridge, UK
| | - Nicholas W Morrell
- Department of Medicine, University of Cambridge, Cambridge, UK. .,NIHR BioResource, Cambridge, UK.
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Chichger H, Rounds S, Harrington EO. Endosomes and Autophagy: Regulators of Pulmonary Endothelial Cell Homeostasis in Health and Disease. Antioxid Redox Signal 2019; 31:994-1008. [PMID: 31190562 PMCID: PMC6765061 DOI: 10.1089/ars.2019.7817] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 06/07/2019] [Indexed: 12/12/2022]
Abstract
Significance: Alterations in oxidant/antioxidant balance injure pulmonary endothelial cells and are important in the pathogenesis of lung diseases, such as Acute Respiratory Distress Syndrome (ARDS), ischemia/reperfusion injury, pulmonary arterial hypertension (PAH), and emphysema. Recent Advances: The endosomal and autophagic pathways regulate cell homeostasis. Both pathways support recycling or degradation of macromolecules or organelles, targeted to endosomes or lysosomes, respectively. Thus, both processes promote cell survival. However, with environmental stress or injury, imbalance in endosomal and autophagic pathways may enhance macromolecular or organelle degradation, diminish biosynthetic processes, and cause cell death. Critical Issues: While the role of autophagy in cellular homeostasis in pulmonary disease has been investigated, the role of the endosome in the lung vasculature is less known. Furthermore, autophagy can either decrease or exacerbate endothelial injury, depending upon inciting insult and disease process. Future Directions: Diseases affecting the pulmonary endothelium, such as emphysema, ARDS, and PAH, are linked to altered endosomal or autophagic processing, leading to enhanced degradation of macromolecules and potential cell death. Efforts to target this imbalance have yielded limited success as treatments for lung injuries, which may be due to the complexity of both processes. It is possible that endosomal trafficking proteins, such as Rab GTPases and late endosomal/lysosomal adaptor, MAPK and MTOR activator 1, may be novel therapeutic targets. While endocytosis or autophagy have been linked to improved function of the pulmonary endothelium in vitro and in vivo, further studies are needed to identify targets for modulating cellular homeostasis in the lung.
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Affiliation(s)
- Havovi Chichger
- Biomedical Research Group, Department of Biomedical and Forensic Sciences, Anglia Ruskin University, Cambridge, United Kingdom
| | - Sharon Rounds
- Vascular Research Laboratory, Providence Veterans Affairs Medical Center, Providence, Rhode Island
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island
| | - Elizabeth O. Harrington
- Vascular Research Laboratory, Providence Veterans Affairs Medical Center, Providence, Rhode Island
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island
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Abstract
The plasma membrane of eukaryotic cells is not a simple sheet of lipids and proteins but is differentiated into subdomains with crucial functions. Caveolae, small pits in the plasma membrane, are the most abundant surface subdomains of many mammalian cells. The cellular functions of caveolae have long remained obscure, but a new molecular understanding of caveola formation has led to insights into their workings. Caveolae are formed by the coordinated action of a number of lipid-interacting proteins to produce a microdomain with a specific structure and lipid composition. Caveolae can bud from the plasma membrane to form an endocytic vesicle or can flatten into the membrane to help cells withstand mechanical stress. The role of caveolae as mechanoprotective and signal transduction elements is reviewed in the context of disease conditions associated with caveola dysfunction.
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Affiliation(s)
- Robert G. Parton
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Queensland 4060, Australia
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Predescu D, Qin S, Patel M, Bardita C, Bhalli R, Predescu S. Epsin15 Homology Domains: Role in the Pathogenesis of Pulmonary Arterial Hypertension. Front Physiol 2018; 9:1393. [PMID: 30333761 PMCID: PMC6176378 DOI: 10.3389/fphys.2018.01393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 09/13/2018] [Indexed: 12/24/2022] Open
Abstract
Intersectin-1s (ITSN) deficiency and expression of a biologically active ITSN fragment, result of granzyme B cleavage under inflammatory conditions associated with pulmonary arterial hypertension (PAH), are characteristics of lung tissue of human and animal models of PAH. Recently, we have shown that this ITSN fragment comprising two Epsin15 homology domains (EHITSN) triggers endothelial cell (EC) proliferation and the plexiform arteriopathy in PAH. Limited evidence also indicates that the EH domains of endocytic proteins such as ITSN, upregulate compensatory endocytic pathways in cells with impaired vesicular trafficking. Thus, we sought to investigate whether the EHITSN may be involved in this compensatory mechanism for improving the EC endocytic dysfunction induced by ITSN deficiency and possibly contribute to PAH pathogenesis. We used stably-transfected human pulmonary artery ECs expressing the Myc-EHITSN (ECEH-ITSN) and ITSN knockout heterozygous mice (K0ITSN+/-) transduced with the Myc-EHITSN, in conjunction with functional assays: the biotin assay for caveolae internalization and 8 nm gold (Au)- and dinitrophenylated (DNP)-albumin perfusion of murine lung microvasculature. Pulmonary artery ECs of PAH patients (ECPAH), ITSN knockdown ECs (ECKD-ITSN), the monocrotaline (MCT)-induced mouse and rat models of PAH, as well as untreated animals, served as controls. ELISA via streptavidin-HRP or anti-DNP antibody (Ab), applied on ECs and lung lysates indicated greater than 30% increase in biotin internalization in ECEH-ITSN compared to ECCtrl. Despite their endocytic deficiency, ECPAH internalized biotin similar to ECCtrl which is twofold higher compared to ECKD-ITSN. Moreover, the lung microvascular bed of Myc-EHITSN-transduced mice and MCT-treated animals showed greater than twofold increase in DNP-BSA transendothelial transport, all compared to untreated controls. Electron microscopy (EM) revealed the increased occurrence of non-conventional endocytic/transcytotic structures (i.e., caveolae clusters, tubulo-vesicular and enlarged endocytic structures, membranous rings), usually underrepresented. Most of these structures were labeled by Au-BSA, consistent with their involvement in the transendothelial transport. Furthermore, ITSN deficiency and EHITSN expression alter the subcellular localization of the EH-binding protein 1 (EHBP1) and cortical actin organization, altogether supporting the increase occurrence/trafficking of the alternative endocytic structures. Thus, the EHITSN by shifting the physiological vesicular (caveolae) transport toward the alternative endocytic pathways is a significant contributor to the dysfunctional molecular phenotype of ECPAH.
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Affiliation(s)
- Dan Predescu
- Division of Pulmonary Medicine, Critical Care and Sleep Medicine, Department of Internal Medicine, Rush Medical College, Rush University, Chicago, IL, United States
| | - Shanshan Qin
- Division of Pulmonary Medicine, Critical Care and Sleep Medicine, Department of Internal Medicine, Rush Medical College, Rush University, Chicago, IL, United States
| | - Monal Patel
- Division of Pulmonary Medicine, Critical Care and Sleep Medicine, Department of Internal Medicine, Rush Medical College, Rush University, Chicago, IL, United States
| | - Cristina Bardita
- Division of Pulmonary Medicine, Critical Care and Sleep Medicine, Department of Internal Medicine, Rush Medical College, Rush University, Chicago, IL, United States
| | - Rabia Bhalli
- Division of Pulmonary Medicine, Critical Care and Sleep Medicine, Department of Internal Medicine, Rush Medical College, Rush University, Chicago, IL, United States
| | - Sanda Predescu
- Division of Pulmonary Medicine, Critical Care and Sleep Medicine, Department of Internal Medicine, Rush Medical College, Rush University, Chicago, IL, United States
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