1
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Gariballa N, Mohamed F, Badawi S, Ali BR. The double whammy of ER-retention and dominant-negative effects in numerous autosomal dominant diseases: significance in disease mechanisms and therapy. J Biomed Sci 2024; 31:64. [PMID: 38937821 PMCID: PMC11210014 DOI: 10.1186/s12929-024-01054-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Accepted: 06/20/2024] [Indexed: 06/29/2024] Open
Abstract
The endoplasmic reticulum (ER) employs stringent quality control mechanisms to ensure the integrity of protein folding, allowing only properly folded, processed and assembled proteins to exit the ER and reach their functional destinations. Mutant proteins unable to attain their correct tertiary conformation or form complexes with their partners are retained in the ER and subsequently degraded through ER-associated protein degradation (ERAD) and associated mechanisms. ER retention contributes to a spectrum of monogenic diseases with diverse modes of inheritance and molecular mechanisms. In autosomal dominant diseases, when mutant proteins get retained in the ER, they can interact with their wild-type counterparts. This interaction may lead to the formation of mixed dimers or aberrant complexes, disrupting their normal trafficking and function in a dominant-negative manner. The combination of ER retention and dominant-negative effects has been frequently documented to cause a significant loss of functional proteins, thereby exacerbating disease severity. This review aims to examine existing literature and provide insights into the impact of dominant-negative effects exerted by mutant proteins retained in the ER in a range of autosomal dominant diseases including skeletal and connective tissue disorders, vascular disorders, neurological disorders, eye disorders and serpinopathies. Most crucially, we aim to emphasize the importance of this area of research, offering substantial potential for understanding the factors influencing phenotypic variability associated with genetic variants. Furthermore, we highlight current and prospective therapeutic approaches targeted at ameliorating the effects of mutations exhibiting dominant-negative effects. These approaches encompass experimental studies exploring treatments and their translation into clinical practice.
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Affiliation(s)
- Nesrin Gariballa
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box: 15551, Al-Ain, United Arab Emirates
| | - Feda Mohamed
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box: 15551, Al-Ain, United Arab Emirates
- ASPIRE Precision Medicine Research Institute Abu Dhabi, United Arab Emirates University, Abu Dhabi, United Arab Emirates
| | - Sally Badawi
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box: 15551, Al-Ain, United Arab Emirates
| | - Bassam R Ali
- Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box: 15551, Al-Ain, United Arab Emirates.
- ASPIRE Precision Medicine Research Institute Abu Dhabi, United Arab Emirates University, Abu Dhabi, United Arab Emirates.
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2
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Sánchez-Duffhues G, Hiepen C. Human iPSCs as Model Systems for BMP-Related Rare Diseases. Cells 2023; 12:2200. [PMID: 37681932 PMCID: PMC10487005 DOI: 10.3390/cells12172200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/17/2023] [Accepted: 08/23/2023] [Indexed: 09/09/2023] Open
Abstract
Disturbances in bone morphogenetic protein (BMP) signalling contribute to onset and development of a number of rare genetic diseases, including Fibrodysplasia ossificans progressiva (FOP), Pulmonary arterial hypertension (PAH), and Hereditary haemorrhagic telangiectasia (HHT). After decades of animal research to build a solid foundation in understanding the underlying molecular mechanisms, the progressive implementation of iPSC-based patient-derived models will improve drug development by addressing drug efficacy, specificity, and toxicity in a complex humanized environment. We will review the current state of literature on iPSC-derived model systems in this field, with special emphasis on the access to patient source material and the complications that may come with it. Given the essential role of BMPs during embryonic development and stem cell differentiation, gain- or loss-of-function mutations in the BMP signalling pathway may compromise iPSC generation, maintenance, and differentiation procedures. This review highlights the need for careful optimization of the protocols used. Finally, we will discuss recent developments towards complex in vitro culture models aiming to resemble specific tissue microenvironments with multi-faceted cellular inputs, such as cell mechanics and ECM together with organoids, organ-on-chip, and microfluidic technologies.
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Affiliation(s)
- Gonzalo Sánchez-Duffhues
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), ISPA-HUCA, Avda. de Roma, s/n, 33011 Oviedo, Spain
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Christian Hiepen
- Department of Engineering and Natural Sciences, Westphalian University of Applied Sciences, August-Schmidt-Ring 10, 45665 Recklinghausen, Germany
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3
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The Role of Bone Morphogenetic Protein Receptor Type 2 ( BMPR2) and the Prospects of Utilizing Induced Pluripotent Stem Cells (iPSCs) in Pulmonary Arterial Hypertension Disease Modeling. Cells 2022; 11:cells11233823. [PMID: 36497082 PMCID: PMC9741276 DOI: 10.3390/cells11233823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 11/25/2022] [Accepted: 11/25/2022] [Indexed: 12/03/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a progressive disease characterized by increased pulmonary vascular resistance (PVR), causing right ventricular hypertrophy and ultimately death from right heart failure. Heterozygous mutations in the bone morphogenetic protein receptor type 2 (BMPR2) are linked to approximately 80% of hereditary, and 20% of idiopathic PAH cases, respectively. While patients carrying a BMPR2 gene mutation are more prone to develop PAH than non-carriers, only 20% will develop the disease, whereas the majority will remain asymptomatic. PAH is characterized by extreme vascular remodeling that causes pulmonary arterial endothelial cell (PAEC) dysfunction, impaired apoptosis, and uncontrolled proliferation of the pulmonary arterial smooth muscle cells (PASMCs). To date, progress in understanding the pathophysiology of PAH has been hampered by limited access to human tissue samples and inadequacy of animal models to accurately mimic the pathogenesis of human disease. Along with the advent of induced pluripotent stem cell (iPSC) technology, there has been an increasing interest in using this tool to develop patient-specific cellular models that precisely replicate the pathogenesis of PAH. In this review, we summarize the currently available approaches in iPSC-based PAH disease modeling and explore how this technology could be harnessed for drug discovery and to widen our understanding of the pathophysiology of PAH.
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4
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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] [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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5
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Ryanto GRT, Ikeda K, Miyagawa K, Tu L, Guignabert C, Humbert M, Fujiyama T, Yanagisawa M, Hirata KI, Emoto N. An endothelial activin A-bone morphogenetic protein receptor type 2 link is overdriven in pulmonary hypertension. Nat Commun 2021; 12:1720. [PMID: 33741934 PMCID: PMC7979873 DOI: 10.1038/s41467-021-21961-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 02/10/2021] [Indexed: 12/12/2022] Open
Abstract
Pulmonary arterial hypertension is a progressive fatal disease that is characterized by pathological pulmonary artery remodeling, in which endothelial cell dysfunction is critically involved. We herein describe a previously unknown role of endothelial angiocrine in pulmonary hypertension. By searching for genes highly expressed in lung microvascular endothelial cells, we identify inhibin-β-A as an angiocrine factor produced by pulmonary capillaries. We find that excess production of inhibin-β-A by endothelial cells impairs the endothelial function in an autocrine manner by functioning as activin-A. Mechanistically, activin-A induces bone morphogenetic protein receptor type 2 internalization and targeting to lysosomes for degradation, resulting in the signal deficiency in endothelial cells. Of note, endothelial cells isolated from the lung of patients with idiopathic pulmonary arterial hypertension show higher inhibin-β-A expression and produce more activin-A compared to endothelial cells isolated from the lung of normal control subjects. When endothelial activin-A-bone morphogenetic protein receptor type 2 link is overdriven in mice, hypoxia-induced pulmonary hypertension was exacerbated, whereas conditional knockout of inhibin-β-A in endothelial cells prevents the progression of pulmonary hypertension. These data collectively indicate a critical role for the dysregulated endothelial activin-A-bone morphogenetic protein receptor type 2 link in the progression of pulmonary hypertension, and thus endothelial inhibin-β-A/activin-A might be a potential pharmacotherapeutic target for the treatment of pulmonary arterial hypertension.
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Affiliation(s)
- Gusty R T Ryanto
- Laboratory of Clinical Pharmaceutical Science, Kobe Pharmaceutical University, Higashinada, Kobe, Japan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo, Kobe, Japan
| | - Koji Ikeda
- Laboratory of Clinical Pharmaceutical Science, Kobe Pharmaceutical University, Higashinada, Kobe, Japan.
- Department of Epidemiology for Longevity and Regional Health, Kyoto Prefectural University of Medicine, Kamigyou, Kyoto, Japan.
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kamigyou, Kyoto, Japan.
| | - Kazuya Miyagawa
- Laboratory of Clinical Pharmaceutical Science, Kobe Pharmaceutical University, Higashinada, Kobe, Japan
| | - Ly Tu
- INSERM UMR_S 999, Le Plessis-Robinson, France
- Université Paris-Saclay, Université Paris-Sud, Le Kremlin-Bicêtre, France
| | - Christophe Guignabert
- INSERM UMR_S 999, Le Plessis-Robinson, France
- Université Paris-Saclay, Université Paris-Sud, Le Kremlin-Bicêtre, France
| | - Marc Humbert
- INSERM UMR_S 999, Le Plessis-Robinson, France
- Université Paris-Saclay, Université Paris-Sud, Le Kremlin-Bicêtre, France
- AP-HP, Service de Pneumologie, Centre de Référence de l'Hypertension Pulmonaire Sévère, DHU Thorax Innovation, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Tomoyuki Fujiyama
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Ken-Ichi Hirata
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo, Kobe, Japan
| | - Noriaki Emoto
- Laboratory of Clinical Pharmaceutical Science, Kobe Pharmaceutical University, Higashinada, Kobe, Japan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo, Kobe, Japan
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6
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Dunmore BJ, Jones RJ, Toshner MR, Upton PD, Morrell NW. Approaches to treat pulmonary arterial hypertension by targeting bmpr2 - from cell membrane to nucleus. Cardiovasc Res 2021; 117:2309-2325. [PMID: 33399862 DOI: 10.1093/cvr/cvaa350] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/06/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is estimated to affect between 10-50 people per million worldwide. The lack of cure and devastating nature of the disease means that treatment is crucial to arrest rapid clinical worsening. Current therapies are limited by their focus on inhibiting residual vasoconstriction rather than targeting key regulators of the cellular pathology. Potential disease-modifying therapies may come from research directed towards causal pathways involved in the cellular and molecular mechanisms of disease. It is widely acknowledged, that targeting reduced expression of the critical bone morphogenetic protein type-2 receptor (BMPR2) and its associated signalling pathways is a compelling therapeutic avenue to explore. In this review we highlight the advances that have been made in understanding this pathway and the therapeutics that are being tested in clinical trials and the clinic to treat PAH.
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Affiliation(s)
- Benjamin J Dunmore
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, UK
| | - Rowena J Jones
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, UK
| | - Mark R Toshner
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, UK
| | - Paul D Upton
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, UK
| | - Nicholas W Morrell
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, UK
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7
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Gariballa N, Ali BR. Endoplasmic Reticulum Associated Protein Degradation (ERAD) in the Pathology of Diseases Related to TGFβ Signaling Pathway: Future Therapeutic Perspectives. Front Mol Biosci 2020; 7:575608. [PMID: 33195419 PMCID: PMC7658374 DOI: 10.3389/fmolb.2020.575608] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/29/2020] [Indexed: 02/05/2023] Open
Abstract
The transforming growth factor signaling pathway (TGFβ) controls a wide range of cellular activities in adulthood as well as during embryogenesis including cell growth, differentiation, apoptosis, immunological responses and other cellular functions. Therefore, germline mutations in components of the pathway have given rise to a heterogeneous spectrum of hereditary diseases with variable phenotypes associated with malformations in the cardiovascular, muscular and skeletal systems. Our extensive literature and database searches revealed 47 monogenic diseases associated with germline mutations in 24 out of 41 gene variant encoding for TGFβ components. Most of the TGFβ components are membrane or secretory proteins and they are therefore expected to pass through the endoplasmic reticulum (ER), where fidelity of proteins folding is stringently monitored via the ER quality control machineries. Elucidation of the molecular mechanisms of mutant proteins’ folding and trafficking showed the implication of ER associated protein degradation (ERAD) in the pathogenesis of some of the diseases. For example, hereditary hemorrhagic telangiectasia types 1 and 2 (HHT1 and HHT2) and familial pulmonary arterial hypertension (FPAH) associated with mutations in Endoglin, ALK1 and BMPR2 components of the signaling pathway, respectively, have all exhibited loss of function phenotype as a result of ER retention of some of their disease-causing variants. In some cases, this has led to premature protein degradation through the proteasomal pathway. We anticipate that ERAD will be involved in the mechanisms of other TGFβ signaling components and therefore warrants further research. In this review, we highlight advances in ER quality control mechanisms and their modulation as a potential therapeutic target in general with particular focus on prospect of their implementation in the treatment of monogenic diseases associated with TGFβ components including HHT1, HHT2, and PAH. In particular, we emphasis the need to establish disease mechanisms and to implement such novel approaches in modulating the molecular pathway of mutant TGFβ components in the quest for restoring protein folding and trafficking as a therapeutic approach.
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Affiliation(s)
- Nesrin Gariballa
- Department of Pathology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.,Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Bassam R Ali
- Department of Pathology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.,Department of Genetics and Genomics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.,Zayed Bin Sultan Center for Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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8
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Dunmore BJ, Yang X, Crosby A, Moore S, Long L, Huang C, Southwood M, Austin ED, Rana A, Upton PD, Morrell NW. 4PBA Restores Signaling of a Cysteine-substituted Mutant BMPR2 Receptor Found in Patients with Pulmonary Arterial Hypertension. Am J Respir Cell Mol Biol 2020; 63:160-171. [PMID: 32255665 DOI: 10.1165/rcmb.2019-0321oc] [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] [Indexed: 02/02/2023] Open
Abstract
Mutations in the gene encoding BMPR2 (bone morphogenetic protein type 2 receptor) are the major cause of heritable pulmonary arterial hypertension (PAH). Point mutations in the BMPR2 ligand-binding domain involving cysteine residues (such as C118W) are causative of PAH and predicted to cause protein misfolding. Using heterologous overexpression systems, we showed previously that these mutations lead to retention of BMPR2 in the endoplasmic reticulum but are partially rescued by chemical chaperones. Here, we sought to determine whether the chemical chaperone 4-phenylbutyrate (4PBA) restores BMPR2 signaling in primary cells and in a knockin mouse harboring a C118W mutation. First, we confirmed dysfunctional BMP signaling in dermal fibroblasts isolated from a family with PAH segregating the BMPR2 C118W mutation. After BMP4 treatment, the induction of downstream signaling targets (Smad1/5, ID1 [inhibitor of DNA binding 1], and ID2) was significantly reduced in C118W mutant cells. Treatment with 4PBA significantly rescued Smad1/5, ID1, and ID2 expression. Pulmonary artery smooth muscle cells isolated from the lungs of heterozygous mice harboring the Bmpr2 C118W mutation exhibited significantly increased proliferation. In the presence of 4PBA, hyperproliferation was dramatically reduced. Furthermore, in vivo, 4PBA treatment of Bmpr2 C118W mice partially rescued Bmpr2 expression, restored downstream signaling, and improved vascular remodeling. These findings demonstrate in primary cells and in a knockin mouse that the repurposed small-molecule chemical chaperone 4PBA might be a promising precision medicine approach to treat PAH in patients with specific subtypes of BMPR2 mutation involving cysteine substitutions in the ligand-binding domain.
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Affiliation(s)
- Benjamin J Dunmore
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - XuDong Yang
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Alexi Crosby
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Stephen Moore
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Lu Long
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Christopher Huang
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Mark Southwood
- Pathology Research, Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom; and
| | - Eric D Austin
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Amer Rana
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Paul D Upton
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Nicholas W Morrell
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
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Hiepen C, Jatzlau J, Hildebrandt S, Kampfrath B, Goktas M, Murgai A, Cuellar Camacho JL, Haag R, Ruppert C, Sengle G, Cavalcanti-Adam EA, Blank KG, Knaus P. BMPR2 acts as a gatekeeper to protect endothelial cells from increased TGFβ responses and altered cell mechanics. PLoS Biol 2019; 17:e3000557. [PMID: 31826007 PMCID: PMC6927666 DOI: 10.1371/journal.pbio.3000557] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 12/23/2019] [Accepted: 11/14/2019] [Indexed: 12/12/2022] Open
Abstract
Balanced transforming growth factor-beta (TGFβ)/bone morphogenetic protein (BMP)-signaling is essential for tissue formation and homeostasis. While gain in TGFβ signaling is often found in diseases, the underlying cellular mechanisms remain poorly defined. Here we show that the receptor BMP type 2 (BMPR2) serves as a central gatekeeper of this balance, highlighted by its deregulation in diseases such as pulmonary arterial hypertension (PAH). We show that BMPR2 deficiency in endothelial cells (ECs) does not abolish pan-BMP-SMAD1/5 responses but instead favors the formation of mixed-heteromeric receptor complexes comprising BMPR1/TGFβR1/TGFβR2 that enable enhanced cellular responses toward TGFβ. These include canonical TGFβ-SMAD2/3 and lateral TGFβ-SMAD1/5 signaling as well as formation of mixed SMAD complexes. Moreover, BMPR2-deficient cells express genes indicative of altered biophysical properties, including up-regulation of extracellular matrix (ECM) proteins such as fibrillin-1 (FBN1) and of integrins. As such, we identified accumulation of ectopic FBN1 fibers remodeled with fibronectin (FN) in junctions of BMPR2-deficient ECs. Ectopic FBN1 deposits were also found in proximity to contractile intimal cells in pulmonary artery lesions of BMPR2-deficient heritable PAH (HPAH) patients. In BMPR2-deficient cells, we show that ectopic FBN1 is accompanied by active β1-integrin highly abundant in integrin-linked kinase (ILK) mechano-complexes at cell junctions. Increased integrin-dependent adhesion, spreading, and actomyosin-dependent contractility facilitates the retrieval of active TGFβ from its latent fibrillin-bound depots. We propose that loss of BMPR2 favors endothelial-to-mesenchymal transition (EndMT) allowing cells of myo-fibroblastic character to create a vicious feed-forward process leading to hyperactivated TGFβ signaling. In summary, our findings highlight a crucial role for BMPR2 as a gatekeeper of endothelial homeostasis protecting cells from increased TGFβ responses and integrin-mediated mechano-transduction.
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Affiliation(s)
- Christian Hiepen
- Freie Universität Berlin, Institute for Chemistry and Biochemistry, Berlin, Germany
| | - Jerome Jatzlau
- Freie Universität Berlin, Institute for Chemistry and Biochemistry, Berlin, Germany
- Berlin-Brandenburg School for Regenerative Therapies, Charité Universitätsmedizin Berlin, Germany
| | - Susanne Hildebrandt
- Freie Universität Berlin, Institute for Chemistry and Biochemistry, Berlin, Germany
- Berlin-Brandenburg School for Regenerative Therapies, Charité Universitätsmedizin Berlin, Germany
| | - Branka Kampfrath
- Freie Universität Berlin, Institute for Chemistry and Biochemistry, Berlin, Germany
| | - Melis Goktas
- Max Planck Institute of Colloids and Interfaces, Mechano(bio)chemistry, Potsdam, Germany
| | - Arunima Murgai
- Freie Universität Berlin, Institute for Chemistry and Biochemistry, Berlin, Germany
- Berlin-Brandenburg School for Regenerative Therapies, Charité Universitätsmedizin Berlin, Germany
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | | | - Rainer Haag
- Freie Universität Berlin, Institute for Chemistry and Biochemistry, Berlin, Germany
| | - Clemens Ruppert
- Universities of Giessen and Marburg Lung Center (UGMLC), Medical Clinic II, Justus Liebig University, Giessen, Germany
| | - Gerhard Sengle
- University of Cologne, Center for Biochemistry, Medical Faculty, Center for Molecular Medicine Cologne (CMMC), Cologne, Germany
| | | | - Kerstin G. Blank
- Max Planck Institute of Colloids and Interfaces, Mechano(bio)chemistry, Potsdam, Germany
| | - Petra Knaus
- Freie Universität Berlin, Institute for Chemistry and Biochemistry, Berlin, Germany
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10
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Tielemans B, Stoian L, Gijsbers R, Michiels A, Wagenaar A, Farre Marti R, Belge C, Delcroix M, Quarck R. Cytokines trigger disruption of endothelium barrier function and p38 MAP kinase activation in BMPR2-silenced human lung microvascular endothelial cells. Pulm Circ 2019; 9:2045894019883607. [PMID: 31692724 PMCID: PMC6811766 DOI: 10.1177/2045894019883607] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/24/2019] [Indexed: 12/21/2022] Open
Abstract
The bone morphogenetic protein receptor II (BMPRII) signaling pathway is impaired
in pulmonary arterial hypertension and mutations in the BMPR2
gene have been observed in both heritable and idiopathic pulmonary arterial
hypertension. However, all BMPR2 mutation carriers do not
develop pulmonary arterial hypertension, and inflammation could trigger the
development of the disease in BMPR2 mutation carriers.
Circulating levels and/or lung tissue expression of cytokines such as tumor
necrosis factor-α or interleukin-18 are elevated in patients with pulmonary
arterial hypertension and could be involved in the pathogenesis of pulmonary
arterial hypertension. We consequently hypothesized that cytokines could trigger
endothelial dysfunction in addition to impaired BMPRII signaling. Our aim was to
determine whether impairment of BMPRII signaling might affect endothelium
barrier function and adhesiveness to monocytes, in response to cytokines.
BMPR2 was silenced in human lung microvascular endothelial
cells (HLMVECs) using lentiviral vectors encoding microRNA-based hairpins.
Effects of tumor necrosis factor-α and interleukin-18 on HLMVEC adhesiveness to
the human monocyte cell line THP-1, adhesion molecule expression, endothelial
barrier function and activation of P38MAPK were investigated in vitro. Stable
BMPR2 silencing in HLMVECs resulted in impaired endothelial
barrier function and constitutive activation of P38MAPK. Adhesiveness of
BMPR2-silenced HLMVECs to THP-1 cells was enhanced by tumor
necrosis factor-α and interleukin-18 through ICAM-1 adhesion molecule.
Interestingly, tumor necrosis factor-α induced activation of P38MAPK and
disrupted endothelial barrier function in BMPR2-silenced
HLMVECs. Altogether, our findings showed that stable BMPR2
silencing resulted in impaired endothelial barrier function and activation of
P38MAPK in HLMVECs. In BMPR2-silenced HLMVECs, cytokines
enhanced adhesiveness capacities, activation of P38MAPK and impaired endothelial
barrier function suggesting that cytokines could trigger the development of
pulmonary arterial hypertension in a context of impaired BMPRII signaling
pathway.
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Affiliation(s)
- Birger Tielemans
- Division of Respiratory Diseases, Department of Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven - University of Leuven, Leuven, Belgium
| | - Leanda Stoian
- Division of Respiratory Diseases, Department of Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven - University of Leuven, Leuven, Belgium
| | - Rik Gijsbers
- Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven - University of Leuven, Leuven, Belgium.,Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven - University of Leuven, Leuven, Belgium
| | - Annelies Michiels
- Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven - University of Leuven, Leuven, Belgium.,Leuven Viral Vector Core, KU Leuven - University of Leuven, Leuven, Belgium
| | - Allard Wagenaar
- Division of Respiratory Diseases, Department of Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven - University of Leuven, Leuven, Belgium
| | - Ricard Farre Marti
- Translational Research in Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven - University of Leuven, Leuven, Belgium
| | - Catharina Belge
- Division of Respiratory Diseases, University Hospitals and Department of Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven - University of Leuven, Leuven, Belgium
| | - Marion Delcroix
- Division of Respiratory Diseases, University Hospitals and Department of Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven - University of Leuven, Leuven, Belgium
| | - Rozenn Quarck
- Division of Respiratory Diseases, University Hospitals and Department of Chronic Diseases, Metabolism & Ageing (CHROMETA), KU Leuven - University of Leuven, Leuven, Belgium
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11
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Choi SH, Jung YK, Jang JA, Han S. Idiopathic pulmonary arterial hypertension associated with a novel frameshift mutation in the bone morphogenetic protein receptor II gene and enhanced bone morphogenetic protein signaling: A case report. Medicine (Baltimore) 2019; 98:e17594. [PMID: 31626133 PMCID: PMC6824762 DOI: 10.1097/md.0000000000017594] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
RATIONALE Idiopathic pulmonary arterial hypertension (IPAH) is characterized by intense remodeling of small pulmonary arteries. Loss-of-function mutation of bone morphogenetic protein receptor II (BMPR2) gene and exaggerated activation of transforming growth factor (TGF)-β signaling play a critical role in this process. PATIENT CONCERNS AND DIAGNOSIS We report a novel frameshift mutation (c.117InsT, p.Y40fsX48) of the BMPR2 gene identified in a 19-year-old IPAH patient with syncope. Despite BMPR2 mutation, the phosphorylation of Smad2/3 and Samd1/5/8 was increased in the patient's peripheral blood mononuclear cells, and this event was accompanied by the upregulation of bone morphogenetic protein (BMP) signaling target genes, but not TGF-β signaling target genes. Moreover, we observed an increased expression of other BMPRs, that is, anti-Mullerian hormone type-2 receptor and the activin receptor-like kinases (ALK) 1, ALK3, and ALK6. INTERVENTIONS AND OUTCOMES The patient was prescribed a combination of macitentan, sildenafil, and nifedipine, which successfully controlled her symptom of syncope and normalized N-terminal pro-brain natriuretic peptide level after 3 months of medication. LESSONS In light of these results, we propose a new pathogenetic mechanism for IPAH, based on enhanced BMP signaling via the functional replacement of mutated BMPR2 by other BMP receptors.
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Affiliation(s)
- Sun Ha Choi
- Department of Internal medicine, Kyungpook National University Hospital, Daegu
| | - Youn-Kwan Jung
- Biomedical Research Institute, Gyeongsang National University Hospital, Jinju, Gyeongsangnam-do
| | - Ji-Ae Jang
- Laboratory for arthritis and bone biology, Fatima Research Institute, Daegu Fatima Hospital, Daegu, Republic of Korea
| | - Seungwoo Han
- Department of Internal medicine, Kyungpook National University Hospital, Daegu
- Laboratory for arthritis and bone biology, Fatima Research Institute, Daegu Fatima Hospital, Daegu, Republic of Korea
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12
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Tielemans B, Delcroix M, Belge C, Quarck R. TGFβ and BMPRII signalling pathways in the pathogenesis of pulmonary arterial hypertension. Drug Discov Today 2019; 24:703-716. [DOI: 10.1016/j.drudis.2018.12.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/06/2018] [Accepted: 12/04/2018] [Indexed: 01/23/2023]
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13
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Abstract
Pulmonary arterial hypertension (PAH) is a pulmonary vasculopathy that causes right ventricular dysfunction and exercise limitation and progresses to death. New findings from translational studies have suggested alternative pathways for treatment. These avenues include sex hormones, genetic abnormalities and DNA damage, elastase inhibition, metabolic dysfunction, cellular therapies, and anti-inflammatory approaches. Both novel and repurposed compounds with rationale from preclinical experimental models and human cells are now in clinical trials in patients with PAH. Findings from these studies will elucidate the pathobiology of PAH and may result in clinically important improvements in outcome.
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Affiliation(s)
- Edda Spiekerkoetter
- Department of Medicine, Stanford University School of Medicine, Stanford, California 94305, USA; ,
| | - Steven M Kawut
- Department of Medicine and Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6021, USA;
| | - Vinicio A de Jesus Perez
- Department of Medicine, Stanford University School of Medicine, Stanford, California 94305, USA; ,
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14
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Frump A, Prewitt A, de Caestecker MP. BMPR2 mutations and endothelial dysfunction in pulmonary arterial hypertension (2017 Grover Conference Series). Pulm Circ 2018; 8:2045894018765840. [PMID: 29521190 PMCID: PMC5912278 DOI: 10.1177/2045894018765840] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 02/26/2018] [Indexed: 12/22/2022] Open
Abstract
Despite the discovery more than 15 years ago that patients with hereditary pulmonary arterial hypertension (HPAH) inherit BMP type 2 receptor ( BMPR2) mutations, it is still unclear how these mutations cause disease. In part, this is attributable to the rarity of HPAH and difficulty obtaining tissue samples from patients with early disease. However, in addition, limitations to the approaches used to study the effects of BMPR2 mutations on the pulmonary vasculature have restricted our ability to determine how individual mutations give rise to progressive pulmonary vascular pathology in HPAH. The importance of understanding the mechanisms by which BMPR2 mutations cause disease in patients with HPAH is underscored by evidence that there is reduced BMPR2 expression in patients with other, more common, non-hereditary form of PAH, and that restoration of BMPR2 expression reverses established disease in experimental models of pulmonary hypertension. In this paper, we focus on the effects on endothelial function. We discuss some of the controversies and challenges that have faced investigators exploring the role of BMPR2 mutations in HPAH, focusing specifically on the effects different BMPR2 mutation have on endothelial function, and whether there are qualitative differences between different BMPR2 mutations. We discuss evidence that BMPR2 signaling regulates a number of responses that may account for endothelial abnormalities in HPAH and summarize limitations of the models that are used to study these effects. Finally, we discuss evidence that BMPR2-dependent effects on endothelial metabolism provides a unifying explanation for the many of the BMPR2 mutation-dependent effects that have been described in patients with HPAH.
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Affiliation(s)
- Andrea Frump
- Division
of Pulmonary, Critical Care, Sleep and Occupational Medicine, Indiana University
School of Medicine, Indianapolis, IN,
USA
| | | | - Mark P. de Caestecker
- Division
of Nephrology and Hypertension, Department of Medicine, Vanderbilt University
Medical center, Nashville, TN, USA
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15
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Hirschhorn T, Levi-Hofman M, Danziger O, Smorodinsky NI, Ehrlich M. Differential molecular regulation of processing and membrane expression of Type-I BMP receptors: implications for signaling. Cell Mol Life Sci 2017; 74:2645-2662. [PMID: 28357470 PMCID: PMC11107780 DOI: 10.1007/s00018-017-2488-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 02/09/2017] [Accepted: 02/13/2017] [Indexed: 12/15/2022]
Abstract
The Type-I bone morphogenetic protein receptors (BMPRs), BMPR1A and BMPR1B, present the highest sequence homology among BMPRs, suggestive of functional similitude. However, sequence elements within their extracellular domain, such as signal sequence or N-glycosylation motifs, may result in differential regulation of biosynthetic processing and trafficking and in alterations to receptor function. We show that (i) BMPR1A and the ubiquitous isoform of BMPR1B differed in mode of translocation into the endoplasmic reticulum; and (ii) BMPR1A was N-glycosylated while BMPR1B was not, resulting in greater efficiency of processing and plasma membrane expression of BMPR1A. We further demonstrated the importance of BMPR1A expression and glycosylation in ES-2 ovarian cancer cells, where (i) CRISPR/Cas9-mediated knockout of BMPR1A abrogated BMP2-induced Smad1/5/8 phosphorylation and reduced proliferation of ES-2 cells and (ii) inhibition of N-glycosylation by site-directed mutagenesis, or by tunicamycin or 2-deoxy-D-glucose treatments, reduced biosynthetic processing and plasma membrane expression of BMPR1A and BMP2-induced Smad1/5/8 phosphorylation.
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Affiliation(s)
- Tal Hirschhorn
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Michal Levi-Hofman
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Oded Danziger
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Nechama I Smorodinsky
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Marcelo Ehrlich
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
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16
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Pousada G, Lupo V, Cástro-Sánchez S, Álvarez-Satta M, Sánchez-Monteagudo A, Baloira A, Espinós C, Valverde D. Molecular and functional characterization of the BMPR2 gene in Pulmonary Arterial Hypertension. Sci Rep 2017; 7:1923. [PMID: 28507310 PMCID: PMC5432510 DOI: 10.1038/s41598-017-02074-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 04/05/2017] [Indexed: 11/09/2022] Open
Abstract
Pulmonary arterial hypertension is a progressive disease that causes the obstruction of precapillary pulmonary arteries and a sustained increase in pulmonary vascular resistance. The aim was to analyze functionally the variants found in the BMPR2 gene and to establish a genotype-phenotype correlation. mRNA expression studies were performed using pSPL3 vector, studies of subcellular localization were performed using pEGFP-N1 vector and luciferase assays were performed using pGL3-Basic vector. We have identified 30 variants in the BMPR2 gene in 27 of 55 patients. In 16 patients we detected pathogenic mutations. Minigene assays revealed that 6 variants (synonymous, missense) result in splicing defect. By immunofluorescence assay, we observed that 4 mutations affect the protein localization. Finally, 4 mutations located in the 5'UTR region showed a decreased transcriptional activity in luciferase assays. Genotype-phenotype correlation, revealed that patients with pathogenic mutations have a more severe phenotype (sPaP p = 0.042, 6MWT p = 0.041), a lower age at diagnosis (p = 0.040) and seemed to have worse response to phosphodiesterase-5-inhibitors (p = 0.010). Our study confirms that in vitro expression analysis is a suitable approach in order to investigate the phenotypic consequences of the nucleotide variants, especially in cases where the involved genes have a pattern of expression in tissues of difficult access.
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Affiliation(s)
- Guillermo Pousada
- Dep. Biochemistry, Genetics and Immunology. Faculty of Biology, University of Vigo, As Lagoas Marcosende S/N, 36310, Vigo, Spain.,Grupo de Investigación Enfermedades Raras y Medicina Pediátrica, Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain
| | - Vincenzo Lupo
- Unit of Genetics and Genomics of Neuromuscular and Neurodegenerative Disorders, Centro de Investigación Príncipe Felipe (CIPF), 46012, Valencia, Spain
| | - Sheila Cástro-Sánchez
- Dep. Biochemistry, Genetics and Immunology. Faculty of Biology, University of Vigo, As Lagoas Marcosende S/N, 36310, Vigo, Spain.,Grupo de Investigación Enfermedades Raras y Medicina Pediátrica, Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain
| | - María Álvarez-Satta
- Dep. Biochemistry, Genetics and Immunology. Faculty of Biology, University of Vigo, As Lagoas Marcosende S/N, 36310, Vigo, Spain.,Grupo de Investigación Enfermedades Raras y Medicina Pediátrica, Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain
| | - Ana Sánchez-Monteagudo
- Unit of Genetics and Genomics of Neuromuscular and Neurodegenerative Disorders, Centro de Investigación Príncipe Felipe (CIPF), 46012, Valencia, Spain
| | - Adolfo Baloira
- Neumology Service, Complexo Hospitalario Universitario de Pontevedra, 36071, Pontevedra, Spain
| | - Carmen Espinós
- Unit of Genetics and Genomics of Neuromuscular and Neurodegenerative Disorders, Centro de Investigación Príncipe Felipe (CIPF), 46012, Valencia, Spain
| | - Diana Valverde
- Dep. Biochemistry, Genetics and Immunology. Faculty of Biology, University of Vigo, As Lagoas Marcosende S/N, 36310, Vigo, Spain. .,Grupo de Investigación Enfermedades Raras y Medicina Pediátrica, Instituto de Investigación Sanitaria Galicia Sur (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain.
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17
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BMP type II receptor as a therapeutic target in pulmonary arterial hypertension. Cell Mol Life Sci 2017; 74:2979-2995. [PMID: 28447104 PMCID: PMC5501910 DOI: 10.1007/s00018-017-2510-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/09/2017] [Accepted: 03/17/2017] [Indexed: 12/30/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a chronic disease characterized by a progressive elevation in mean pulmonary arterial pressure. This occurs due to abnormal remodeling of small peripheral lung vasculature resulting in progressive occlusion of the artery lumen that eventually causes right heart failure and death. The most common cause of PAH is inactivating mutations in the gene encoding a bone morphogenetic protein type II receptor (BMPRII). Current therapeutic options for PAH are limited and focused mainly on reversal of pulmonary vasoconstriction and proliferation of vascular cells. Although these treatments can relieve disease symptoms, PAH remains a progressive lethal disease. Emerging data suggest that restoration of BMPRII signaling in PAH is a promising alternative that could prevent and reverse pulmonary vascular remodeling. Here we will focus on recent advances in rescuing BMPRII expression, function or signaling to prevent and reverse pulmonary vascular remodeling in PAH and its feasibility for clinical translation. Furthermore, we summarize the role of described miRNAs that directly target the BMPR2 gene in blood vessels. We discuss the therapeutic potential and the limitations of promising new approaches to restore BMPRII signaling in PAH patients. Different mutations in BMPR2 and environmental/genetic factors make PAH a heterogeneous disease and it is thus likely that the best approach will be patient-tailored therapies.
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18
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Frump AL, Datta A, Ghose S, West J, de Caestecker MP. Genotype-phenotype effects of Bmpr2 mutations on disease severity in mouse models of pulmonary hypertension. Pulm Circ 2017; 6:597-607. [PMID: 28090303 DOI: 10.1086/688930] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
More than 350 mutations in the type-2 BMP (bone morphogenetic protein) receptor, BMPR2, have been identified in patients with heritable pulmonary arterial hypertension (HPAH). However, only 30% of BMPR2 mutation carriers develop PAH, and we cannot predict which of these carriers will develop clinical disease. One possibility is that the nature of the BMPR2 mutation affects disease severity. This hypothesis has been difficult to test clinically, given the rarity of HPAH and the complexity of the confounding genetic and environmental risk factors. To test this hypothesis, therefore, we evaluated the susceptibility to experimental pulmonary hypertension (PH) of mice carrying different HPAH-associated Bmpr2 mutations on otherwise identical genetic backgrounds. Mice with Bmpr2ΔEx4-5 mutations (Bmpr2+/-), in which the mutant protein is not expressed, develop less severe PH in response to hypoxia or hypoxia with vascular endothelial growth factor receptor inhibition than mice with an extracellular-domain Bmpr2ΔEx2 mutation (Bmpr2ΔEx2/+), in which the mutant protein is expressed. This was associated with a marked decrease in stabilizing phosphorylation of threonine 495 endothelial nitric oxide synthase (pThr495 eNOS) in Bmpr2ΔEx2/+ compared to wild-type and Bmpr2+/- mouse lungs. These findings provide the first experimental evidence that BMPR2 mutation types influence the severity of HPAH and suggest that patients with BMPR2 mutations who express mutant BMPR2 proteins by escaping non-sense-mediated messenger RNA decay (NMD- mutations) will develop more severe disease than HPAH patients with NMD+ mutations who do not express BMPR2 mutant proteins. Since decreased levels of pThr495 eNOS are associated with increased eNOS uncoupling, our data also suggest that this effect may result from defects in eNOS function.
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Affiliation(s)
- Andrea L Frump
- Department of Cell and Developmental Biology, Vanderbilt University, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Arunima Datta
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Sampa Ghose
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - James West
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mark P de Caestecker
- Department of Cell and Developmental Biology, Vanderbilt University, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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19
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Ma L, Chung WK. The role of genetics in pulmonary arterial hypertension. J Pathol 2016; 241:273-280. [PMID: 27770446 DOI: 10.1002/path.4833] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 09/30/2016] [Accepted: 10/17/2016] [Indexed: 12/14/2022]
Abstract
Group 1 pulmonary hypertension or pulmonary arterial hypertension (PAH) is a rare disease characterized by proliferation and occlusion of small pulmonary arterioles, leading to progressive elevation of pulmonary artery pressure and pulmonary vascular resistance, and right ventricular failure. Historically, it has been associated with a high mortality rate, although, over the last decade, treatment has improved survival. PAH includes idiopathic PAH (IPAH), heritable PAH (HPAH), and PAH associated with certain medical conditions. The aetiology of PAH is heterogeneous, and genetics play an important role in some cases. Mutations in BMPR2, encoding bone morphogenetic protein receptor 2, a member of the transforming growth factor-β superfamily of receptors, have been identified in 70% of cases of HPAH, and in 10-40% of cases of IPAH. Other genetic causes of PAH include mutations in the genes encoding activin receptor-like type 1, endoglin, SMAD9, caveolin 1, and potassium two-pore-domain channel subfamily K member 3. Mutations in the gene encoding T-box 4 have been identified in 10-30% of paediatric PAH patients, but rarely in adults with PAH. PAH in children is much more heterogeneous than in adults, and can be associated with several genetic syndromes, congenital heart disease, pulmonary disease, and vascular disease. In addition to rare mutations as a monogenic cause of HPAH, common variants in the gene encoding cerebellin 2 increase the risk of PAH by approximately two-fold. A PAH panel of genes is available for clinical testing, and should be considered for use in clinical management, especially for patients with a family history of PAH. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Lijiang Ma
- Department of Pediatrics, Columbia University, New York, NY, USA
| | - Wendy K Chung
- Department of Pediatrics, Columbia University, New York, NY, USA.,Department of Medicine, Columbia University, New York, NY, USA
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20
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Wu Y, Adi D, Long M, Wang J, Liu F, Gai MT, Aierken A, Li MY, Li Q, Wu LQ, Ma YT, Hujiaaihemaiti M. 4-Phenylbutyric Acid Induces Protection against Pulmonary Arterial Hypertension in Rats. PLoS One 2016; 11:e0157538. [PMID: 27304885 PMCID: PMC4909300 DOI: 10.1371/journal.pone.0157538] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 06/01/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Endoplasmic reticulum (ER) stress has been implicated in the pathophysiology of various pulmonary diseases via the activation of the unfolded protein response. However, the role of ER stress in pulmonary arterial hypertension (PAH) remains unclear. The well-known chemical chaperone 4-phenylbutyric acid (4-PBA) inhibits ER stress signaling. We hypothesized that known chemical chaperones, including 4-PBA, would inhibit the activation of ER stress and prevent and/or reverse PAH. METHODS AND RESULTS Male Wistar rats were randomly divided into four groups: a normal control group (NORMAL group), a PAH group, and two PAH model plus 4-PBA treatment groups. The latter two groups included rats receiving 4-PBA by gavage each day as a preventive measure (the PRE group, with PBA starting on the day of PAH induction and continuing for 4 weeks) or as a reversal measure (the REV group, with PBA starting on the third week of PAH induction and continuing for 2 weeks). The PAH model was induced by intraperitoneally administering monocrotaline. The mean pulmonary artery pressure and mean right ventricular pressure were lower in the REV and PRE groups than in the NORMAL group. Furthermore, 4-PBA improved pulmonary arterial remodeling and suppressed the expression of ER stress indicators. CONCLUSION Our findings indicate that PAH induces ER stress and provokes pulmonary arterial and right ventricular remodeling. Additionally, we show that attenuation of ER stress has the potential to be an effective therapeutic strategy for protecting pulmonary arteries.
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Affiliation(s)
- Yun Wu
- Department of General Practice, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
- Department of Cardiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Dilare Adi
- Department of Cardiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Mei Long
- Department of Mechanism and Function, Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Jie Wang
- Department of Pharmacy, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Fen Liu
- Xinjiang Key Laboratory of Cardiovascular Disease Research, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Min-Tao Gai
- Xinjiang Key Laboratory of Cardiovascular Disease Research, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Alidan Aierken
- Department of General Practice, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Ming-Yuan Li
- Department of General Practice, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Qian Li
- Department of General Practice, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Lei-Qi Wu
- Department of General Practice, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
| | - Yi-Tong Ma
- Xinjiang Key Laboratory of Cardiovascular Disease Research, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
- Department of Cardiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
- * E-mail: (Y-TM); (MH)
| | - Minawaer Hujiaaihemaiti
- Department of General Practice, First Affiliated Hospital of Xinjiang Medical University, Urumqi, 830011 P.R., China
- * E-mail: (Y-TM); (MH)
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21
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Amsalem AR, Marom B, Shapira KE, Hirschhorn T, Preisler L, Paarmann P, Knaus P, Henis YI, Ehrlich M. Differential regulation of translation and endocytosis of alternatively spliced forms of the type II bone morphogenetic protein (BMP) receptor. Mol Biol Cell 2016; 27:716-30. [PMID: 26739752 PMCID: PMC4750929 DOI: 10.1091/mbc.e15-08-0547] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/24/2015] [Indexed: 12/22/2022] Open
Abstract
The cytoplasmic extension of the long-form isoform of BMPRII, unique among TGF-β superfamily receptors, is found to regulate the translation of BMPRII and its clathrin-mediated endocytosis. Both processes reduce its cell surface levels. The higher expression of BMPRII-SF at the plasma membrane results in enhanced activation of Smad signaling. The expression and function of transforming growth factor-β superfamily receptors are regulated by multiple molecular mechanisms. The type II BMP receptor (BMPRII) is expressed as two alternatively spliced forms, a long and a short form (BMPRII-LF and –SF, respectively), which differ by an ∼500 amino acid C-terminal extension, unique among TGF-β superfamily receptors. Whereas this extension was proposed to modulate BMPRII signaling output, its contribution to the regulation of receptor expression was not addressed. To map regulatory determinants of BMPRII expression, we compared synthesis, degradation, distribution, and endocytic trafficking of BMPRII isoforms and mutants. We identified translational regulation of BMPRII expression and the contribution of a 3’ terminal coding sequence to this process. BMPRII-LF and -SF differed also in their steady-state levels, kinetics of degradation, intracellular distribution, and internalization rates. A single dileucine signal in the C-terminal extension of BMPRII-LF accounted for its faster clathrin-mediated endocytosis relative to BMPRII-SF, accompanied by mildly faster degradation. Higher expression of BMPRII-SF at the plasma membrane resulted in enhanced activation of Smad signaling, stressing the potential importance of the multilayered regulation of BMPRII expression at the plasma membrane.
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Affiliation(s)
- Ayelet R Amsalem
- Department of Neurobiology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Barak Marom
- Department of Neurobiology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Keren E Shapira
- Department of Neurobiology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tal Hirschhorn
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Livia Preisler
- Department of Neurobiology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Pia Paarmann
- Institute for Chemistry and Biochemistry, Freie Univesitaet Berlin, 1495 Berlin, Germany
| | - Petra Knaus
- Institute for Chemistry and Biochemistry, Freie Univesitaet Berlin, 1495 Berlin, Germany
| | - Yoav I Henis
- Department of Neurobiology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Marcelo Ehrlich
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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22
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Long L, Ormiston ML, Yang X, Southwood M, Gräf S, Machado RD, Mueller M, Kinzel B, Yung LM, Wilkinson JM, Moore SD, Drake KM, Aldred MA, Yu P, Upton PD, Morrell NW. Selective enhancement of endothelial BMPR-II with BMP9 reverses pulmonary arterial hypertension. Nat Med 2015; 21:777-85. [PMID: 26076038 PMCID: PMC4496295 DOI: 10.1038/nm.3877] [Citation(s) in RCA: 329] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/12/2015] [Indexed: 12/13/2022]
Abstract
Genetic evidence implicates the loss of bone morphogenetic protein type II receptor (BMPR-II) signaling in the endothelium as an initiating factor in pulmonary arterial hypertension (PAH). However, selective targeting of this signaling pathway using BMP ligands has not yet been explored as a therapeutic strategy. Here, we identify BMP9 as the preferred ligand for preventing apoptosis and enhancing monolayer integrity in both pulmonary arterial endothelial cells and blood outgrowth endothelial cells from subjects with PAH who bear mutations in the gene encoding BMPR-II, BMPR2. Mice bearing a heterozygous knock-in allele of a human BMPR2 mutation, R899X, which we generated as an animal model of PAH caused by BMPR-II deficiency, spontaneously developed PAH. Administration of BMP9 reversed established PAH in these mice, as well as in two other experimental PAH models, in which PAH develops in response to either monocrotaline or VEGF receptor inhibition combined with chronic hypoxia. These results demonstrate the promise of direct enhancement of endothelial BMP signaling as a new therapeutic strategy for PAH.
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Affiliation(s)
- Lu Long
- University of Cambridge, Department of Medicine, Addenbrooke’s Hospital, Cambridge, UK
| | - Mark L. Ormiston
- University of Cambridge, Department of Medicine, Addenbrooke’s Hospital, Cambridge, UK
| | - Xudong Yang
- University of Cambridge, Department of Medicine, Addenbrooke’s Hospital, Cambridge, UK
| | - Mark Southwood
- Department of Pathology, Papworth Hospital, Papworth Everard, UK
| | - Stefan Gräf
- University of Cambridge, Department of Medicine, Addenbrooke’s Hospital, Cambridge, UK
| | | | | | - Bernd Kinzel
- Novartis Institute for Biomedical Research, Basel, CH
| | - Lai Ming Yung
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA
| | - Janine M. Wilkinson
- University of Cambridge, Department of Medicine, Addenbrooke’s Hospital, Cambridge, UK
| | - Stephen D. Moore
- University of Cambridge, Department of Medicine, Addenbrooke’s Hospital, Cambridge, UK
| | - Kylie M. Drake
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Cleveland, OH
| | - Micheala A. Aldred
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Cleveland, OH
| | - Paul Yu
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA
| | - Paul D. Upton
- University of Cambridge, Department of Medicine, Addenbrooke’s Hospital, Cambridge, UK
| | - Nicholas W. Morrell
- University of Cambridge, Department of Medicine, Addenbrooke’s Hospital, Cambridge, UK
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23
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John A, Kizhakkedath P, Al-Gazali L, Ali BR. Defective cellular trafficking of the bone morphogenetic protein receptor type II by mutations underlying familial pulmonary arterial hypertension. Gene 2015; 561:148-56. [PMID: 25688877 DOI: 10.1016/j.gene.2015.02.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 01/26/2015] [Accepted: 02/12/2015] [Indexed: 02/05/2023]
Abstract
Familial pulmonary arterial hypertension (FPAH) is a relatively rare but fatal disorder characterized by elevated arterial pressure caused by abnormal proliferation of endothelial cells of the arteries, which eventually leads to heart failure and death. FPAH is inherited as an autosomal dominant trait and is caused by heterozygous mutations in the BMPR2 gene encoding the bone morphogenetic protein type II receptor (BMPR2). BMPR2 belongs to the TGF β/BMP super-family of receptors involved in a signal transduction cascade via the SMAD signaling pathway. The BMPR2 polypeptide is composed of 1038 amino acids and consists of a ligand binding domain, a kinase domain and a cytoplasmic tail. To investigate the cellular and functional consequence of BMPR2 mutations, C-terminally FLAG-tagged constructs of eighteen pathogenic BMPR2 missense mutants were generated by site directed mutagenesis and expressed in HeLa and HEK-293T cell lines. The subcellular localizations of the mutant proteins were investigated using immunostaining and confocal microscopy. Post-translational modifications of the proteins were analyzed by Endoglycosidase H deglycosylation assay. Our results indicated that mutations in the ligand binding domain affecting highly conserved cysteine residues resulted in retention of the mutant proteins in the endoplasmic reticulum (ER), as evident from their co-localization with the ER resident protein calnexin. The kinase domain mutants showed both ER and plasma membrane (PM) distributions, while the cytoplasmic tail domain variants were localized exclusively to the PM. The subcellular localizations of the mutants were further confirmed by their characteristic glycosylation profiles. In conclusion, our results indicate that ER quality control (ERQC) is involved in the pathological mechanism of several BMPR2 receptor missense mutations causing FPAH, which can be explored as a potential therapeutic target in the future.
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Affiliation(s)
- Anne John
- Department of Pathology, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Praseetha Kizhakkedath
- Department of Pathology, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Lihadh Al-Gazali
- Department of Pediatrics, College of Medicine and Heath Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Bassam R Ali
- Department of Pathology, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates.
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24
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Hirschhorn T, di Clemente N, Amsalem AR, Pepinsky RB, Picard JY, Smorodinsky NI, Cate RL, Ehrlich M. Constitutive negative regulation in the processing of the anti-Müllerian hormone receptor II. J Cell Sci 2015; 128:1352-64. [PMID: 25663701 DOI: 10.1242/jcs.160143] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The levels and intracellular localization of wild-type transforming growth factor β superfamily (TGFβ-SF) receptors are tightly regulated by endocytic trafficking, shedding and degradation. In contrast, a main regulatory mechanism of mutation-bearing receptors involves their intracellular retention. Anti-Müllerian hormone receptor II (AMHRII, also known as AMHR2) is the type-II receptor for anti-Müllerian hormone (AMH), a TGFβ-SF ligand that mediates Müllerian duct regression in males. Here, we studied AMHRII processing and identified novel mechanisms of its constitutive negative regulation. Immunoblot analysis revealed that a significant portion of AMHRII was missing most of its extracellular domain (ECD) and, although glycosylated, was unfolded and retained in the endoplasmic reticulum. Exogenous expression of AMHRII, but not of type-II TGF-β receptor (TβRII, also known as TGFR2), resulted in its disulfide-bond-mediated homo-oligomerization and intracellular retention, and in a decrease in its AMH-binding capacity. At the plasma membrane, AMHRII differed from TβRII, forming high levels of non-covalent homomeric complexes, which exhibited a clustered distribution and restricted lateral mobility. This study identifies novel mechanisms of negative regulation of a type-II TGFβ-SF receptor through cleavage, intracellular retention and/or promiscuous disulfide-bond mediated homo-oligomerization.
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Affiliation(s)
- Tal Hirschhorn
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel 69978
| | - Nathalie di Clemente
- Université Paris Diderot, Sorbonne Paris Cité, Biologie Fonctionnelle et Adaptative (BFA), F-75013 Paris, France CNRS, UMR 8251, Biologie Fonctionnelle et Adaptative, F-75013 Paris, France INSERM U1133, Physiologie de l'Axe Gonadotrope, F-75013 Paris, France
| | - Ayelet R Amsalem
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - R Blake Pepinsky
- Biogen-Idec, Inc., 14 Cambridge Center, Cambridge, MA 02142, USA
| | - Jean-Yves Picard
- INSERM U1133, Physiologie de l'Axe Gonadotrope, F-75013 Paris, France
| | - Nechama I Smorodinsky
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel 69978
| | - Richard L Cate
- INSERM U1133, Physiologie de l'Axe Gonadotrope, F-75013 Paris, France Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA
| | - Marcelo Ehrlich
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel-Aviv, Israel 69978
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25
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Guignabert C, Tu L, Girerd B, Ricard N, Huertas A, Montani D, Humbert M. New Molecular Targets of Pulmonary Vascular Remodeling in Pulmonary Arterial Hypertension. Chest 2015; 147:529-537. [DOI: 10.1378/chest.14-0862] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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26
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D'Agostino M, Crespi A, Polishchuk E, Generoso S, Martire G, Colombo SF, Bonatti S. ER reorganization is remarkably induced in COS-7 cells accumulating transmembrane protein receptors not competent for export from the endoplasmic reticulum. J Membr Biol 2014; 247:1149-59. [PMID: 25086772 DOI: 10.1007/s00232-014-9710-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/15/2014] [Indexed: 10/24/2022]
Abstract
The newly synthesized mutant L501fsX533 Frizzled-4 form and the alpha3beta4 nicotinic acetylcholine receptor expressed in the absence of nicotine accumulate in the endoplasmic reticulum of COS-7 cells and induce the formation of large areas of smooth and highly convoluted cisternae. This results in a generalized block of the transport to the Golgi complex of newly synthesized proteins. Intriguingly, both effects happen peculiarly in COS-7 cells; HeLa, Huh-7, and HEK293 cells expressing the two receptors at similar level than COS-7 cells show normal ER and normal transport toward the plasma membrane. These results question the conclusion that a dominant-negative mechanism would explain the dominance of the mutant L501fsX533 Fz4 allele in the transmission of a form of Familial exudative vitreoretinopathy. Moreover, they indicate that the coordination of endoplasmic reticulum homeostasis in COS-7 cells is particularly error prone. This finding suggests that COS-7 cells may be extremely useful to study the molecular mechanisms regulating endoplasmic reticulum size and architecture.
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Affiliation(s)
- Massimo D'Agostino
- Department of Molecular medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
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27
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Girerd B, Perros F, Antigny F, Humbert M, Montani D. KCNK3: new gene target for pulmonary hypertension? Expert Rev Respir Med 2014; 8:385-7. [PMID: 24742047 DOI: 10.1586/17476348.2014.909731] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recently, KCNK3 has been identified as a new predisposing gene for pulmonary arterial hypertension (PAH) by whole-exome sequencing. Mutation in KCNK3 gene is responsible for the first channelopathy identified in PAH. PAH due to KCNK3 mutations is an autosomal dominant disease with an incomplete penetrance as previously described in PAH due to BMPR2 mutations. This discovery represents an important advance for genetic counselling, allowing identification of high risk relatives for PAH and possible screening for PAH in KCNK3 mutation carriers.
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28
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Lowery JW, Amich JM, Andonian A, Rosen V. N-linked glycosylation of the bone morphogenetic protein receptor type 2 (BMPR2) enhances ligand binding. Cell Mol Life Sci 2013; 71:3165-72. [PMID: 24337809 DOI: 10.1007/s00018-013-1541-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Revised: 11/28/2013] [Accepted: 12/02/2013] [Indexed: 02/07/2023]
Abstract
The bone morphogenetic protein (BMP) signaling pathway is essential for normal development and tissue homeostasis. BMP signal transduction occurs when ligands interact with a complex of type 1 and type 2 receptors to activate downstream transcription factors. It is well established that a single BMP receptor may bind multiple BMP ligands with varying affinity, and this has been largely attributed to conformation at the amino acid level. However, all three type 2 BMP receptors (BMPR2, ACVR2A/B) contain consensus N-glycosylation sites in their extracellular domains (ECDs), which could play a role in modulating interaction with ligand. Here, we show a differential pattern of N-glycosylation between BMPR2 and ACVR2A/B. Site-directed mutagenesis reveals that BMPR2 is uniquely glycosylated near its ligand binding domain and at a position that is mutated in patients with heritable pulmonary arterial hypertension. We further demonstrate using a cell-free pulldown assay that N-glycosylation of the BMPR2-ECD enhances its ability to bind BMP2 ligand but has no impact on binding by the closely-related ACVR2B. Our results illuminate a novel aspect of BMP signaling pathway mechanics and demonstrate a functional difference resulting from post-translational modification of type 2 BMP receptors. Additionally, since BMPR2 is required for several aspects of normal development and defects in its function are strongly implicated in human disease, our findings are likely to be relevant in several biological contexts in normal and abnormal human physiology.
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Affiliation(s)
- Jonathan W Lowery
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA,
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