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Tee A, Jones RA, Dunlop EA, Champion J, Doubleday P, Claessens T, Jalali Z, Seifan S, Perry I, Giles P, Harrison O, Coull B, Houweling A, Pause A, Ballif B. Characterizing the tumor suppressor activity of FLCN in Birt-Hogg-Dubé syndrome through transcriptiomic and proteomic analysis. RESEARCH SQUARE 2024:rs.3.rs-4510670. [PMID: 38978568 PMCID: PMC11230511 DOI: 10.21203/rs.3.rs-4510670/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Birt-Hogg-Dubé (BHD) syndrome patients are uniquely susceptible to all renal tumour subtypes. The underlying mechanism of carcinogenesis is unclear. To study cancer development in BHD, we used human proximal kidney (HK2) cells and found that long-term folliculin (FLCN) knockdown was required to increase their tumorigenic potential, forming larger spheroids in non-adherent conditions. Transcriptomic and proteomic analysis uncovered links between FLCN, cell cycle control and the DNA damage response (DDR) machinery. HK2 cells lacking FLCN had an altered transcriptome profile with cell cycle control gene enrichment. G1/S cell cycle checkpoint signaling was compromised with heightened protein levels of cyclin D1 (CCND1) and hyperphosphorylation of retinoblastoma 1 (RB1). A FLCN interactome screen uncovered FLCN binding to DNA-dependent protein kinase (DNA-PK). This novel interaction was reversed in an irradiation-responsive manner. Knockdown of FLCN in HK2 cells caused a marked elevation of γH2AX and RB1 phosphorylation. Both CCND1 and RB1 phosphorylation remained raised during DNA damage, showing an association with defective cell cycle control with FLCN knockdown. Furthermore, Flcn-knockdown C. elegans were defective in cell cycle arrest by DNA damage. This work implicates that long-term FLCN loss and associated cell cycle defects in BHD patients could contribute to their increased risk of cancer.
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2
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Prosseda PP, Dannewitz Prosseda S, Tran M, Liton PB, Sun Y. Crosstalk between the mTOR pathway and primary cilia in human diseases. Curr Top Dev Biol 2023; 155:1-37. [PMID: 38043949 PMCID: PMC11227733 DOI: 10.1016/bs.ctdb.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Autophagy is a fundamental catabolic process whereby excessive or damaged cytoplasmic components are degraded through lysosomes to maintain cellular homeostasis. Studies of mTOR signaling have revealed that mTOR controls biomass generation and metabolism by modulating key cellular processes, including protein synthesis and autophagy. Primary cilia, the assembly of which depends on kinesin molecular motors, serve as sensory organelles and signaling platforms. Given these pathways' central role in maintaining cellular and physiological homeostasis, a connection between mTOR and primary cilia signaling is starting to emerge in a variety of diseases. In this review, we highlight recent advances in our understanding of the complex crosstalk between the mTOR pathway and cilia and discuss its function in the context of related diseases.
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Affiliation(s)
- Philipp P Prosseda
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | | | - Matthew Tran
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Paloma B Liton
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, United States
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States; Palo Alto Veterans Administration Medical Center, Palo Alto, CA, United States.
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3
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Tsang TH, Wiese M, Helmstädter M, Stehle T, Seyfferth J, Shvedunova M, Holz H, Walz G, Akhtar A. Transcriptional regulation by the NSL complex enables diversification of IFT functions in ciliated versus nonciliated cells. SCIENCE ADVANCES 2023; 9:eadh5598. [PMID: 37624894 PMCID: PMC10456878 DOI: 10.1126/sciadv.adh5598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 07/25/2023] [Indexed: 08/27/2023]
Abstract
Members of the NSL histone acetyltransferase complex are involved in multiorgan developmental syndromes. While the NSL complex is known for its importance in early development, its role in fully differentiated cells remains enigmatic. Using a kidney-specific model, we discovered that deletion of NSL complex members KANSL2 or KANSL3 in postmitotic podocytes led to catastrophic kidney dysfunction. Systematic comparison of two primary differentiated cell types reveals the NSL complex as a master regulator of intraciliary transport genes in both dividing and nondividing cells. NSL complex ablation led to loss of cilia and impaired sonic hedgehog pathway in ciliated fibroblasts. By contrast, nonciliated podocytes responded with altered microtubule dynamics and obliterated podocyte functions. Finally, overexpression of wild-type but not a double zinc finger (ZF-ZF) domain mutant of KANSL2 rescued the transcriptional defects, revealing a critical function of this domain in NSL complex assembly and function. Thus, the NSL complex exhibits bifurcation of functions to enable diversity of specialized outcomes in differentiated cells.
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Affiliation(s)
- Tsz Hong Tsang
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
- International Max Planck Research School for Molecular and Cellular Biology (IMPRS-MCB), 79108 Freiburg, Germany
| | - Meike Wiese
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Martin Helmstädter
- Department of Medicine IV, University Freiburg Medical Center, Faculty of Medicine, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
| | - Thomas Stehle
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Janine Seyfferth
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Maria Shvedunova
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Herbert Holz
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Gerd Walz
- Department of Medicine IV, University Freiburg Medical Center, Faculty of Medicine, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
| | - Asifa Akhtar
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
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4
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Morleo M, Vieira HL, Pennekamp P, Palma A, Bento-Lopes L, Omran H, Lopes SS, Barral DC, Franco B. Crosstalk between cilia and autophagy: implication for human diseases. Autophagy 2023; 19:24-43. [PMID: 35613303 PMCID: PMC9809938 DOI: 10.1080/15548627.2022.2067383] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Macroautophagy/autophagy is a self-degradative process necessary for cells to maintain their energy balance during development and in response to nutrient deprivation. Autophagic processes are tightly regulated and have been found to be dysfunctional in several pathologies. Increasing experimental evidence points to the existence of an interplay between autophagy and cilia. Cilia are microtubule-based organelles protruding from the cell surface of mammalian cells that perform a variety of motile and sensory functions and, when dysfunctional, result in disorders known as ciliopathies. Indeed, selective autophagic degradation of ciliary proteins has been shown to control ciliogenesis and, conversely, cilia have been reported to control autophagy. Moreover, a growing number of players such as lysosomal and mitochondrial proteins are emerging as actors of the cilia-autophagy interplay. However, some of the published data on the cilia-autophagy axis are contradictory and indicate that we are just starting to understand the underlying molecular mechanisms. In this review, the current knowledge about this axis and challenges are discussed, as well as the implication for ciliopathies and autophagy-associated disorders.
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Affiliation(s)
- Manuela Morleo
- Telethon Institute of Genetics and Medicine (TIGEM), 80078, Pozzuoli, Italy,Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, Naples, Italy
| | - Helena L.A. Vieira
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal,UCIBIO, Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal,Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Petra Pennekamp
- Department of General Pediatrics, University Hospital Münster, University of Münster, Münster48149, Germany,Member of the European Reference Networks ERN-LUNG, Lisbon, Portugal
| | - Alessandro Palma
- Department of Onco-hematology, Gene and Cell Therapy, Bambino Gesù Children’s Hospital - IRCCS, Rome, Italy
| | - Liliana Bento-Lopes
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal
| | - Heymut Omran
- Department of General Pediatrics, University Hospital Münster, University of Münster, Münster48149, Germany,Member of the European Reference Networks ERN-LUNG, Lisbon, Portugal
| | - Susana S. Lopes
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal,Member of the European Reference Networks ERN-LUNG, Lisbon, Portugal
| | - Duarte C. Barral
- CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal
| | - Brunella Franco
- Telethon Institute of Genetics and Medicine (TIGEM), 80078, Pozzuoli, Italy,Medical Genetics, Department of Translational Medical Science, University of Naples “Federico II”, Naples, Italy,Scuola Superiore Meridionale, School for Advanced Studies, Naples, Italy,CONTACT Brunella Franco CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, Lisboa1169-056, Portugal
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5
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Webster BR, Gopal N, Ball MW. Tumorigenesis Mechanisms Found in Hereditary Renal Cell Carcinoma: A Review. Genes (Basel) 2022; 13:2122. [PMID: 36421797 PMCID: PMC9690265 DOI: 10.3390/genes13112122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/07/2022] [Accepted: 11/11/2022] [Indexed: 09/29/2023] Open
Abstract
Renal cell carcinoma is a heterogenous cancer composed of an increasing number of unique subtypes each with their own cellular and tumor behavior. The study of hereditary renal cell carcinoma, which composes just 5% of all types of tumor cases, has allowed for the elucidation of subtype-specific tumorigenesis mechanisms that can also be applied to their sporadic counterparts. This review will focus on the major forms of hereditary renal cell carcinoma and the genetic alterations contributing to their tumorigenesis, including von Hippel Lindau syndrome, Hereditary Papillary Renal Cell Carcinoma, Succinate Dehydrogenase-Deficient Renal Cell Carcinoma, Hereditary Leiomyomatosis and Renal Cell Carcinoma, BRCA Associated Protein 1 Tumor Predisposition Syndrome, Tuberous Sclerosis, Birt-Hogg-Dubé Syndrome and Translocation RCC. The mechanisms for tumorigenesis described in this review are beginning to be exploited via the utilization of novel targets to treat renal cell carcinoma in a subtype-specific fashion.
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Affiliation(s)
| | | | - Mark W. Ball
- Center for Cancer Research, Urologic Oncology Branch, National Cancer Institute/NIH, 10 Center Drive, CRC Room 2W-5940, Bethesda, MD 20892, USA
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6
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Claude-Taupin A, Dupont N, Codogno P. Autophagy and the primary cilium in cell metabolism: What’s upstream? Front Cell Dev Biol 2022; 10:1046248. [PMID: 36438551 PMCID: PMC9682156 DOI: 10.3389/fcell.2022.1046248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/25/2022] [Indexed: 11/11/2022] Open
Abstract
The maintenance of cellular homeostasis in response to extracellular stimuli, i.e., nutrient and hormone signaling, hypoxia, or mechanical forces by autophagy, is vital for the health of various tissues. The primary cilium (PC) is a microtubule-based sensory organelle that regulates the integration of several extracellular stimuli. Over the past decade, an interconnection between autophagy and PC has begun to be revealed. Indeed, the PC regulates autophagy and in turn, a selective form of autophagy called ciliophagy contributes to the regulation of ciliogenesis. Moreover, the PC regulates both mitochondrial biogenesis and lipophagy to produce free fatty acids. These two pathways converge to activate oxidative phosphorylation and produce ATP, which is mandatory for cell metabolism and membrane transport. The autophagy-dependent production of energy is fully efficient when the PC senses shear stress induced by fluid flow. In this review, we discuss the cross-talk between autophagy, the PC and physical forces in the regulation of cell biology and physiology.
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Affiliation(s)
| | - Nicolas Dupont
- *Correspondence: Aurore Claude-Taupin, ; Nicolas Dupont, ; Patrice Codogno,
| | - Patrice Codogno
- *Correspondence: Aurore Claude-Taupin, ; Nicolas Dupont, ; Patrice Codogno,
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7
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Wang T, Yang Y, Feng H, Cui B, Lv Z, Zhao W, Zhang X, Ma X. Concurrent Germline and Somatic Mutations in FLCN and Preliminary Exploration of Its Function: A Case Report. Front Oncol 2022; 12:877470. [PMID: 35664771 PMCID: PMC9162506 DOI: 10.3389/fonc.2022.877470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/22/2022] [Indexed: 11/14/2022] Open
Abstract
Birt-Hogg-Dube syndrome is an autosomal dominant condition that arises from germline folliculin (FLCN) mutations. It is characterized by skin fibrofolliculomas, lung cysts, pneumothorax, and renal cancer. Here, we present the case of a 36-year-old woman with asymptomatic, multiple renal tumors and a history of spontaneous pneumothorax. Genetic analysis revealed a hotspot FLCN germline mutation, c.1285dupC (p.H429fs), and a novel somatic mutation, c.470delT (p.F157fs). This information and the results of immunohistochemical analysis of the renal tumors indicated features compatible with a tumor suppressor role of FLCN. Two transcription factors, oncogenic TFEB and TFE3, were shown to be regulated by FLCN inactivation, which results in their nuclear localization. We showed that a deficiency in the tumor suppressor FLCN leads to deregulation of the mammalian target of rapamycin signaling (mTOR) pathway. A potential link between FLCN mutation and ciliary length was also examined. Thus, the mutation identified in our patient provides novel insights into the relationship among FLCN mutations, TFEB/TFE3, mTOR, and cilia. However, an in-depth understanding of the role of folliculin in the molecular pathogenesis of renal cancer requires further study.
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Affiliation(s)
- Tao Wang
- Department of Urology, The Third Medical Centre, Chinese People’s Liberation Army (PLA) General Hospital, Beijing, China
- Medical School of Chinese People’s Liberation Army (PLA), Beijing, China
| | - Yang Yang
- Department of Urology, The Third Medical Centre, Chinese People’s Liberation Army (PLA) General Hospital, Beijing, China
- Medical School of Chinese People’s Liberation Army (PLA), Beijing, China
| | - Huayi Feng
- Department of Urology, The Third Medical Centre, Chinese People’s Liberation Army (PLA) General Hospital, Beijing, China
- Medical School of Chinese People’s Liberation Army (PLA), Beijing, China
| | - Bo Cui
- Department of Urology, The Third Medical Centre, Chinese People’s Liberation Army (PLA) General Hospital, Beijing, China
- Medical School of Chinese People’s Liberation Army (PLA), Beijing, China
| | - Zheng Lv
- Department of Urology, The Third Medical Centre, Chinese People’s Liberation Army (PLA) General Hospital, Beijing, China
- Medical School of Chinese People’s Liberation Army (PLA), Beijing, China
| | - Wenlei Zhao
- Department of Urology, The Third Medical Centre, Chinese People’s Liberation Army (PLA) General Hospital, Beijing, China
- Medical School of Chinese People’s Liberation Army (PLA), Beijing, China
| | - Xiangyi Zhang
- Department of Urology, The Third Medical Centre, Chinese People’s Liberation Army (PLA) General Hospital, Beijing, China
- Medical School of Chinese People’s Liberation Army (PLA), Beijing, China
| | - Xin Ma
- Department of Urology, The Third Medical Centre, Chinese People’s Liberation Army (PLA) General Hospital, Beijing, China
- Medical School of Chinese People’s Liberation Army (PLA), Beijing, China
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8
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Lagerstedt-Robinson K, Baranowska Körberg I, Tsiaprazis S, Björck E, Tham E, Poluha A, Hellström Pigg M, Paulsson-Karlsson Y, Nordenskjöld M, Johansson-Soller M, Aravidis C. A retrospective two centre study of Birt-Hogg-Dubé syndrome reveals a pathogenic founder mutation in FLCN in the Swedish population. PLoS One 2022; 17:e0264056. [PMID: 35176117 PMCID: PMC8853502 DOI: 10.1371/journal.pone.0264056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 02/02/2022] [Indexed: 11/18/2022] Open
Abstract
Birt-Hogg-Dube syndrome (BHDS) (MIM: 135150) is a rare autosomal dominant disorder with variable penetrance, caused by pathogenic variants in the FLCN gene. Only a few hundreds of families have so far been described in the literature. Patients with BHDS present with three distinct symptoms: fibrofolliculomas, pneumothorax due to lung cyst formation, and increased lifetime risk of kidney tumours. The aim of the current study was to estimate the incidence of BHDS in the Swedish population and further describe the clinical manifestations and their frequency. Splice variant c.779+1G>T was the most common pathogenic variant, found in 57% of the families, suggesting this may be a founder mutation in the Swedish population. This was further investigated using haplotype analysis in 50 families that shared a common haplotype. Moreover, according to gnomAD the carrier frequency of the c.779+1G>T variant has been estimated to be 1/3265 in the Swedish population, however our data suggest that the carrier frequency in the Swedish population may be significantly higher. These findings should raise awareness among physicians of different specialties to patients presenting with fibrofolliculomas, pneumothorax and/or kidney tumours. We also stress the importance of consensus recommendations regarding diagnosis and clinical management of this, not that uncommon, syndrome.
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Affiliation(s)
- Kristina Lagerstedt-Robinson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Izabella Baranowska Körberg
- Department of Immunology, Genetics and Pathology, Uppsala University, Science for Life Laboratory, Uppsala, Sweden
- Department of Clinical Genetics, Uppsala University Hospital, Uppsala, Sweden
| | - Stefanos Tsiaprazis
- Department of Immunology, Genetics and Pathology, Uppsala University, Science for Life Laboratory, Uppsala, Sweden
- Department of Clinical Genetics, Uppsala University Hospital, Uppsala, Sweden
| | - Erik Björck
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Emma Tham
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Anna Poluha
- Department of Immunology, Genetics and Pathology, Uppsala University, Science for Life Laboratory, Uppsala, Sweden
- Department of Clinical Genetics, Uppsala University Hospital, Uppsala, Sweden
| | - Maritta Hellström Pigg
- Department of Immunology, Genetics and Pathology, Uppsala University, Science for Life Laboratory, Uppsala, Sweden
- Department of Clinical Genetics, Uppsala University Hospital, Uppsala, Sweden
| | - Ylva Paulsson-Karlsson
- Department of Immunology, Genetics and Pathology, Uppsala University, Science for Life Laboratory, Uppsala, Sweden
- Department of Clinical Genetics, Uppsala University Hospital, Uppsala, Sweden
| | - Magnus Nordenskjöld
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Maria Johansson-Soller
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Solna, Stockholm, Sweden
| | - Christos Aravidis
- Department of Immunology, Genetics and Pathology, Uppsala University, Science for Life Laboratory, Uppsala, Sweden
- Department of Clinical Genetics, Uppsala University Hospital, Uppsala, Sweden
- * E-mail:
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9
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Primary cilium-dependent autophagy in the response to shear stress. Biochem Soc Trans 2021; 49:2831-2839. [PMID: 34747995 DOI: 10.1042/bst20210810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 12/21/2022]
Abstract
Mechanical forces, such as compression, shear stress and stretching, play major roles during development, tissue homeostasis and immune processes. These forces are translated into a wide panel of biological responses, ranging from changes in cell morphology, membrane transport, metabolism, energy production and gene expression. Recent studies demonstrate the role of autophagy in the integration of these physical constraints. Here we focus on the role of autophagy in the integration of shear stress induced by blood and urine flows in the circulatory system and the kidney, respectively. Many studies highlight the involvement of the primary cilium, a microtubule-based antenna present at the surface of many cell types, in the integration of extracellular stimuli. The cross-talk between the molecular machinery of autophagy and that of the primary cilium in the context of shear stress is revealed to be an important dialog in cell biology.
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10
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Focșa IO, Budișteanu M, Bălgrădean M. Clinical and genetic heterogeneity of primary ciliopathies (Review). Int J Mol Med 2021; 48:176. [PMID: 34278440 PMCID: PMC8354309 DOI: 10.3892/ijmm.2021.5009] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 06/28/2021] [Indexed: 01/11/2023] Open
Abstract
Ciliopathies comprise a group of complex disorders, with involvement of the majority of organs and systems. In total, >180 causal genes have been identified and, in addition to Mendelian inheritance, oligogenicity, genetic modifications, epistatic interactions and retrotransposon insertions have all been described when defining the ciliopathic phenotype. It is remarkable how the structural and functional impairment of a single, minuscule organelle may lead to the pathogenesis of highly pleiotropic diseases. Thus, combined efforts have been made to identify the genetic substratum and to determine the pathophysiological mechanism underlying the clinical presentation, in order to diagnose and classify ciliopathies. Yet, predicting the phenotype, given the intricacy of the genetic cause and overlapping clinical characteristics, represents a major challenge. In the future, advances in proteomics, cell biology and model organisms may provide new insights that could remodel the field of ciliopathies.
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Affiliation(s)
- Ina Ofelia Focșa
- Department of Medical Genetics, University of Medicine and Pharmacy 'Carol Davila', 021901 Bucharest, Romania
| | - Magdalena Budișteanu
- Department of Pediatric Neurology, 'Prof. Dr. Alexandru Obregia' Clinical Hospital of Psychiatry, 041914 Bucharest, Romania
| | - Mihaela Bălgrădean
- Department of Pediatrics and Pediatric Nephrology, Emergency Clinical Hospital for Children 'Maria Skłodowska Curie', 077120 Bucharest, Romania
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11
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Abstract
Autophagy is a major intracellular degradation system and plays important roles in various physiological processes such as metabolic adaptation and intracellular homeostasis. It degrades intracellular components both randomly and selectively. Autophagic activity is tightly regulated primarily by nutrient availability, but also by other extracellular and intracellular signals. Growing evidence suggests that there are multiple links between autophagy and the primary cilium. The primary cilium is an organelle present on the cell surface and is important for keeping cellular integrity by transducing extracellular stimuli inside the cell. Recent studies have revealed that autophagy selectively degrades the ciliogenesis inhibitory proteins OFD1 and MYH9, promoting ciliogenesis. Conversely, autophagy also inhibits ciliogenesis under growth conditions. The primary cilium can also regulate autophagic activity. These findings suggest that the relationship between autophagy and the primary cilia is bidirectional, and that both are important for maintaining the normal function of various organs.
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Affiliation(s)
- Yasuhiro Yamamoto
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Noboru Mizushima
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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12
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Yu L, Wei J, Liu P. Attacking the PI3K/Akt/mTOR signaling pathway for targeted therapeutic treatment in human cancer. Semin Cancer Biol 2021; 85:69-94. [PMID: 34175443 DOI: 10.1016/j.semcancer.2021.06.019] [Citation(s) in RCA: 152] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 06/10/2021] [Accepted: 06/22/2021] [Indexed: 02/08/2023]
Abstract
Cancer is the second leading cause of human death globally. PI3K/Akt/mTOR signaling is one of the most frequently dysregulated signaling pathways observed in cancer patients that plays crucial roles in promoting tumor initiation, progression and therapy responses. This is largely due to that PI3K/Akt/mTOR signaling is indispensable for many cellular biological processes, including cell growth, metastasis, survival, metabolism, and others. As such, small molecule inhibitors targeting major kinase components of the PI3K/Akt/mTOR signaling pathway have drawn extensive attention and been developed and evaluated in preclinical models and clinical trials. Targeting a single kinase component within this signaling usually causes growth arrest rather than apoptosis associated with toxicity-induced adverse effects in patients. Combination therapies including PI3K/Akt/mTOR inhibitors show improved patient response and clinical outcome, albeit developed resistance has been reported. In this review, we focus on revealing the mechanisms leading to the hyperactivation of PI3K/Akt/mTOR signaling in cancer and summarizing efforts for developing PI3K/Akt/mTOR inhibitors as either mono-therapy or combination therapy in different cancer settings. We hope that this review will facilitate further understanding of the regulatory mechanisms governing dysregulation of PI3K/Akt/mTOR oncogenic signaling in cancer and provide insights into possible future directions for targeted therapeutic regimen for cancer treatment, by developing new agents, drug delivery systems, or combination regimen to target the PI3K/Akt/mTOR signaling pathway. This information will also provide effective patient stratification strategy to improve the patient response and clinical outcome for cancer patients with deregulated PI3K/Akt/mTOR signaling.
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Affiliation(s)
- Le Yu
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | - Pengda Liu
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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13
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Glykofridis IE, Knol JC, Balk JA, Westland D, Pham TV, Piersma SR, Lougheed SM, Derakhshan S, Veen P, Rooimans MA, van Mil SE, Böttger F, Poddighe PJ, van de Beek I, Drost J, Zwartkruis FJ, de Menezes RX, Meijers-Heijboer HE, Houweling AC, Jimenez CR, Wolthuis RM. Loss of FLCN-FNIP1/2 induces a non-canonical interferon response in human renal tubular epithelial cells. eLife 2021; 10:61630. [PMID: 33459596 PMCID: PMC7899648 DOI: 10.7554/elife.61630] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 01/16/2021] [Indexed: 12/14/2022] Open
Abstract
Germline mutations in the Folliculin (FLCN) tumor suppressor gene cause Birt–Hogg–Dubé (BHD) syndrome, a rare autosomal dominant disorder predisposing carriers to kidney tumors. FLCN is a conserved, essential gene linked to diverse cellular processes but the mechanism by which FLCN prevents kidney cancer remains unknown. Here, we show that disrupting FLCN in human renal tubular epithelial cells (RPTEC/TERT1) activates TFE3, upregulating expression of its E-box targets, including RRAGD and GPNMB, without modifying mTORC1 activity. Surprisingly, the absence of FLCN or its binding partners FNIP1/FNIP2 induces interferon response genes independently of interferon. Mechanistically, FLCN loss promotes STAT2 recruitment to chromatin and slows cellular proliferation. Our integrated analysis identifies STAT1/2 signaling as a novel target of FLCN in renal cells and BHD tumors. STAT1/2 activation appears to counterbalance TFE3-directed hyper-proliferation and may influence immune responses. These findings shed light on unique roles of FLCN in human renal tumorigenesis and pinpoint candidate prognostic biomarkers.
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Affiliation(s)
- Iris E Glykofridis
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Jaco C Knol
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Medical Oncology, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Jesper A Balk
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Denise Westland
- University Medical Center Utrecht, Center for Molecular Medicine, Molecular Cancer Research, Universiteitsweg, Utrecht, Netherlands
| | - Thang V Pham
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Medical Oncology, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Sander R Piersma
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Medical Oncology, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Sinéad M Lougheed
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Medical Oncology, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Sepide Derakhshan
- Princess Máxima Center for Pediatric Oncology, Oncode Institute, Heidelberglaan, Utrecht, Netherlands
| | - Puck Veen
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Martin A Rooimans
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Saskia E van Mil
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Franziska Böttger
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Medical Oncology, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Pino J Poddighe
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Amsterdam, Netherlands
| | - Irma van de Beek
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Amsterdam, Netherlands
| | - Jarno Drost
- Princess Máxima Center for Pediatric Oncology, Oncode Institute, Heidelberglaan, Utrecht, Netherlands
| | - Fried Jt Zwartkruis
- University Medical Center Utrecht, Center for Molecular Medicine, Molecular Cancer Research, Universiteitsweg, Utrecht, Netherlands
| | | | - Hanne Ej Meijers-Heijboer
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Arjan C Houweling
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Amsterdam, Netherlands
| | - Connie R Jimenez
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Medical Oncology, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Rob Mf Wolthuis
- Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Clinical Genetics, Cancer Center Amsterdam, Amsterdam, Netherlands
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14
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Zhang Y, Liu Y, Dai Y, Ren Y, Bao G, Bo A, Jiang Y. Ciliary localization of folliculin mediated via a kinesin-2-binding motif is required for its functions in mTOR regulation and tumor suppression. FEBS Lett 2021; 595:123-132. [PMID: 33064845 PMCID: PMC7980781 DOI: 10.1002/1873-3468.13959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/18/2020] [Accepted: 09/28/2020] [Indexed: 12/19/2022]
Abstract
Folliculin (FLCN) is a tumor suppressor protein involved in many cellular processes, including cell signaling, apoptosis, and autophagy. In ciliated cells, FLCN localizes to primary cilia and controls mTORC1 signaling in response to flow stress. Here, we show that the ciliary localization of FLCN requires its interaction with kinesin-2, the motor protein for anterograde intraflagellar transport. FLCN binds to kinesin-2 through a loop region in the middle of the protein. Single point mutations within this region of FLCN disrupt its kinesin-2 binding and ciliary entry. The mutants lose the ability to suppress the abnormal mTORC1/2 signaling activities and anchorage-independent growth of FLCN-deficient tumor cells. These observations suggest that ciliary localization of FLCN is essential for its function as a tumor suppressor.
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Affiliation(s)
- Yunlong Zhang
- Department of Bioengineering, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China
| | - Ying Liu
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yu Dai
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yazhe Ren
- Department of Bioengineering, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China
| | - Guangsen Bao
- Department of Bioengineering, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China
| | - Ai Bo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yu Jiang
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
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15
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Lymphoplasmacytic lymphoma in a patient with Birt-Hogg-Dubé syndrome. Int J Hematol 2020; 112:864-870. [PMID: 32789566 DOI: 10.1007/s12185-020-02970-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/28/2020] [Accepted: 08/06/2020] [Indexed: 10/23/2022]
Abstract
Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant disease characterized by benign skin hamartomas, pulmonary cysts leading to spontaneous pneumothorax, and an increased risk of renal cancer. BHD syndrome is caused by germline mutations in the folliculin (FLCN) gene, a putative tumor suppressor, which result in loss of function of the folliculin protein and may cause cancer predisposition. In a 45-year-old woman with anemia, lymphadenopathy, and a history of recurrent spontaneous pneumothorax, 18F-FDG PET/CT detected diffuse and slight 18F-FDG accumulation in the bone marrow, enlarged spleen, and systemic multiple enlarged lymph nodes. Genetic examination identified a germline nonsense mutation [c.998C > G (p.Ser333*)] on exon 9 of FLCN. Pathological examination of the lymph node revealed a diffuse neoplastic proliferation of plasmacytoid lymphocytes. The neoplastic lymphoid cells were positive for CD20, CD138, and light chain kappa as per immunohistochemistry and mRNA in situ hybridization, and a MYD88 gene mutation [c.755T > C (p.L252P)] was identified. Accordingly, she was diagnosed with lymphoplasmacytic lymphoma concomitant with BHD syndrome. To the best of our knowledge, this is the first report describing the development of hematological malignancy in a patient with BHD syndrome. The FLCN mutation might contribute lymphomagenesis as an additional mutation cooperating with the MYD88 mutation.
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16
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Oguchi ME, Okuyama K, Homma Y, Fukuda M. A comprehensive analysis of Rab GTPases reveals a role for Rab34 in serum starvation-induced primary ciliogenesis. J Biol Chem 2020; 295:12674-12685. [PMID: 32669361 DOI: 10.1074/jbc.ra119.012233] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 07/14/2020] [Indexed: 12/17/2022] Open
Abstract
Primary cilia are sensors of chemical and mechanical signals in the extracellular environment. The formation of primary cilia (i.e. ciliogenesis) requires dynamic membrane trafficking events, and several Rab small GTPases, key regulators of membrane trafficking, have recently been reported to participate in ciliogenesis. However, the precise mechanisms of Rab-mediated membrane trafficking during ciliogenesis remain largely unknown. In the present study, we used a collection of siRNAs against 62 human Rabs to perform a comprehensive knockdown screening for Rabs that regulate serum starvation-induced ciliogenesis in human telomerase reverse transcriptase retinal pigment epithelium 1 (hTERT-RPE1) cells and succeeded in identifying Rab34 as an essential Rab. Knockout (KO) of Rab34, but not of Rabs previously reported to regulate ciliogenesis (e.g. Rab8 and Rab10) in hTERT-RPE1 cells, drastically impaired serum starvation-induced ciliogenesis. Rab34 was also required for serum starvation-induced ciliogenesis in NIH/3T3 cells and MCF10A cells but not for ciliogenesis in Madin-Darby canine kidney (MDCK)-II cysts. We then attempted to identify a specific region(s) of Rab34 that is essential for ciliogenesis by performing deletion and mutation analyses of Rab34. Unexpectedly, instead of a specific sequence in the switch II region, which is generally important for recognizing effector proteins (e.g. Rab interacting lysosomal protein [RILP]), a unique long N-terminal region of Rab34 before the conserved GTPase domain was found to be essential. These findings suggest that Rab34 is an atypical Rab that regulates serum starvation-induced ciliogenesis through its unique N-terminal region.
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Affiliation(s)
- Mai E Oguchi
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
| | - Koki Okuyama
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
| | - Yuta Homma
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
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17
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Reciprocal Regulation between Primary Cilia and mTORC1. Genes (Basel) 2020; 11:genes11060711. [PMID: 32604881 PMCID: PMC7349257 DOI: 10.3390/genes11060711] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 12/11/2022] Open
Abstract
In quiescent cells, primary cilia function as a mechanosensor that converts mechanic signals into chemical activities. This unique organelle plays a critical role in restricting mechanistic target of rapamycin complex 1 (mTORC1) signaling, which is essential for quiescent cells to maintain their quiescence. Multiple mechanisms have been identified that mediate the inhibitory effect of primary cilia on mTORC1 signaling. These mechanisms depend on several tumor suppressor proteins localized within the ciliary compartment, including liver kinase B1 (LKB1), AMP-activated protein kinase (AMPK), polycystin-1, and polycystin-2. Conversely, changes in mTORC1 activity are able to affect ciliogenesis and stability indirectly through autophagy. In this review, we summarize recent advances in our understanding of the reciprocal regulation of mTORC1 and primary cilia.
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18
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Kennedy JC, Khabibullin D, Hougard T, Nijmeh J, Shi W, Henske EP. Loss of FLCN inhibits canonical WNT signaling via TFE3. Hum Mol Genet 2020; 28:3270-3281. [PMID: 31272105 DOI: 10.1093/hmg/ddz158] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/10/2019] [Accepted: 07/01/2019] [Indexed: 12/13/2022] Open
Abstract
Lower lobe predominant pulmonary cysts occur in up to 90% of patients with Birt-Hogg-Dubé (BHD) syndrome, but the key pathologic cell type and signaling events driving this distinct phenotype remain elusive. Through examination of the LungMAP database, we found that folliculin (FLCN) is highly expressed in neonatal lung mesenchymal cells. Using RNA-Seq, we found that inactivation of Flcn in mouse embryonic fibroblasts leads to changes in multiple Wnt ligands, including a 2.8-fold decrease in Wnt2. This was associated with decreased TCF/LEF activity, a readout of canonical WNT activity, after treatment with a GSK3-α/β inhibitor. Similarly, FLCN deficiency in HEK293T cells decreased WNT pathway activity by 76% post-GSK3-α/β inhibition. Inactivation of FLCN in human fetal lung fibroblasts (MRC-5) led to ~ 100-fold decrease in Wnt2 expression and a 33-fold decrease in Wnt7b expression-two ligands known to be necessary for lung development. Furthermore, canonical WNT activity was decreased by 60%. Classic WNT targets such as AXIN2 and BMP4, and WNT enhanceosome members including TCF4, LEF1 and BCL9 were also decreased after GSK3-α/β inhibition. FLCN-deficient MRC-5 cells failed to upregulate LEF1 in response to GSK3-α/β inhibition. Finally, we found that a constitutively active β-catenin could only partially rescue the decreased WNT activity phenotype seen in FLCN-deficient cells, whereas silencing the transcription factor TFE3 completely reversed this phenotype. In summary, our data establish FLCN as a critical regulator of the WNT pathway via TFE3 and suggest that FLCN-dependent defects in WNT pathway developmental cues may contribute to lung cyst pathogenesis in BHD.
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Affiliation(s)
- John C Kennedy
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.,Division of Pulmonary and Respiratory Diseases, Boston Children's Hospital, Boston, MA 02115, USA
| | - Damir Khabibullin
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Thomas Hougard
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Julie Nijmeh
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Wei Shi
- Department of Surgery, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Elizabeth P Henske
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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19
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Enomoto Y, Namba Y, Hoshika Y, Komemushi Y, Mitani K, Kume H, Kobayashi E, Miyama Y, Homma Y, Ushiku T, Seyama K. A case of Birt-Hogg-Dubé syndrome implying reduced or no wild-type folliculin without mutated protein is pathogenic. Eur J Med Genet 2019; 63:103820. [PMID: 31778855 DOI: 10.1016/j.ejmg.2019.103820] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/16/2019] [Accepted: 11/24/2019] [Indexed: 10/25/2022]
Abstract
Birt-Hogg-Dubé syndrome (BHDS) is an autosomal dominant cancer syndrome caused by a germline mutation of the folliculin (FLCN) gene. Previous studies have suggested that truncated mutant folliculin proteins generated by disease causing FLCN mutations may retain partial functionality and contribute to disease phenotype. A 38-year-old Russian man presented with a left renal tumor. He underwent a left radical nephrectomy and histological examination confirmed the diagnosis of chromophobe renal cell carcinoma. He had papulae on his face suggestive of fibrofolliculomas, and pulmonary cysts on his computed tomography of the chest. He had a family history of skin manifestations. Genetic analysis identified a genomic deletion including the putative promoter region of FLCN exon 1 in the germline, and the second hit on the remaining wild-type FLCN in the renal carcinoma cells, which is expected to cause the complete lack of folliculin protein. Immunohistochemistry with the use of anti-folliculin antibody showed no antibody-binding on chromophobe renal carcinoma cells. These findings suggest that the decreased FLCN expression itself without producing mutated folliculin proteins can be at risk for developing clinical manifestations of BHDS: fibrofolliculomas, lung cysts, and tumorigenesis in the kidneys. This sheds light on the pathogenesis of BHDS and the role of FLCN as a tumor suppressor gene.
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Affiliation(s)
- Yutaka Enomoto
- Division of Urology, Mitsui Memorial Hospital, 1 Kanda-izumi-cho, Chiyoda-ku, Tokyo, 101-8643, Japan.
| | - Yukiko Namba
- Divisions of Respiratory Medicine, Juntendo University Faculty of Medicine and Graduate School of Medicine, 3-1-3 Hongo, Bunkyo-Ku, Tokyo, 113-8431, Japan.
| | - Yoshihito Hoshika
- Divisions of Respiratory Medicine, Juntendo University Faculty of Medicine and Graduate School of Medicine, 3-1-3 Hongo, Bunkyo-Ku, Tokyo, 113-8431, Japan.
| | - Yoshimitsu Komemushi
- Department of Urology, JCHO Saitama Medical Center, 4-9-3 Kitaurawa, Urawa-ku, Saitama-shi, Saitama, 330-0074, Japan.
| | - Keiko Mitani
- Divisions of Respiratory Medicine, Juntendo University Faculty of Medicine and Graduate School of Medicine, 3-1-3 Hongo, Bunkyo-Ku, Tokyo, 113-8431, Japan.
| | - Haruki Kume
- Department of Urology, University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
| | - Etsuko Kobayashi
- Divisions of Respiratory Medicine, Juntendo University Faculty of Medicine and Graduate School of Medicine, 3-1-3 Hongo, Bunkyo-Ku, Tokyo, 113-8431, Japan.
| | - Yu Miyama
- Department of Pathology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
| | - Yukio Homma
- Department of Urology, University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
| | - Tetsuo Ushiku
- Department of Pathology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-8655, Japan.
| | - Kuniaki Seyama
- Divisions of Respiratory Medicine, Juntendo University Faculty of Medicine and Graduate School of Medicine, 3-1-3 Hongo, Bunkyo-Ku, Tokyo, 113-8431, Japan.
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20
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The Autophagy-Cilia Axis: An Intricate Relationship. Cells 2019; 8:cells8080905. [PMID: 31443299 PMCID: PMC6721705 DOI: 10.3390/cells8080905] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/08/2019] [Accepted: 08/12/2019] [Indexed: 01/19/2023] Open
Abstract
Primary cilia are microtubule-based organelles protruding from the surface of almost all vertebrate cells. This organelle represents the cell’s antenna which acts as a communication hub to transfer extracellular signals into intracellular responses during development and in tissue homeostasis. Recently, it has been shown that loss of cilia negatively regulates autophagy, the main catabolic route of the cell, probably utilizing the autophagic machinery localized at the peri-ciliary compartment. On the other side, autophagy influences ciliogenesis in a context-dependent manner, possibly to ensure that the sensing organelle is properly formed in a feedback loop model. In this review we discuss the recent literature and propose that the autophagic machinery and the ciliary proteins are functionally strictly related to control both autophagy and ciliogenesis. Moreover, we report examples of diseases associated with autophagic defects which cause cilia abnormalities, and propose and discuss the hypothesis that, at least some of the clinical manifestations observed in human diseases associated to ciliary disfunction may be the result of a perturbed autophagy.
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21
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Zemirli N, Boukhalfa A, Dupont N, Botti J, Codogno P, Morel E. The primary cilium protein folliculin is part of the autophagy signaling pathway to regulate epithelial cell size in response to fluid flow. Cell Stress 2019; 3:100-109. [PMID: 31225504 PMCID: PMC6551741 DOI: 10.15698/cst2019.03.180] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Autophagy is a conserved molecular pathway directly involved in the degradation and recycling of intracellular components. Autophagy is associated with a response to stress situations, such as nutrients deficit, chemical toxicity, mechanical stress or microbial host defense. We have recently shown that primary cilium-dependent autophagy is important to control kidney epithelial cell size in response to fluid flow induced shear stress. Here we show that the ciliary protein folliculin (FLCN) actively participates to the signaling cascade leading to the stimulation of fluid flow-dependent autophagy upstream of the cell size regulation in HK2 kidney epithelial cells. The knockdown of FLCN induces a shortening of the primary cilium, inhibits the activation of AMPK and the recruitment of the autophagy protein ATG16L1 at the primary cilium. Altogether, our results suggest that FLCN is essential in the dialog between autophagy and the primary cilium in epithelial cells to integrate shear stress-dependent signaling.
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Affiliation(s)
- Naïma Zemirli
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253.,Université Paris Descartes-Sorbonne Paris Cité, F-75993, Paris, France
| | - Asma Boukhalfa
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253.,Université Paris Descartes-Sorbonne Paris Cité, F-75993, Paris, France
| | - Nicolas Dupont
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253.,Université Paris Descartes-Sorbonne Paris Cité, F-75993, Paris, France
| | - Joëlle Botti
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253.,Université Paris Denis Diderot Sorbonne Paris Cité, F-75993, Paris, France
| | - Patrice Codogno
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253.,Université Paris Descartes-Sorbonne Paris Cité, F-75993, Paris, France
| | - Etienne Morel
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253.,Université Paris Descartes-Sorbonne Paris Cité, F-75993, Paris, France
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22
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Birt-Hogg-Dubé Syndrome: A Review of Dermatological Manifestations and Other Symptoms. Am J Clin Dermatol 2018; 19:87-101. [PMID: 28695430 DOI: 10.1007/s40257-017-0307-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant genodermatosis with malignant potential characterized by cutaneous and extracutaneous stigmata. Aberrations in the folliculin (FLCN) gene, which is located on chromosome 17, have been discovered in individuals with this condition. Over 150 unique mutations have been identified in BHD. The skin lesions associated with this condition include fibrofolliculomas, trichodiscomas, perifollicular fibromas, and acrochordons. Extracutaneous features of the syndrome typically include the lung (spontaneous pneumothorax and cysts) and the kidney (neoplasms). The only malignancies associated with BHD are renal cancers; however, other tumors have been observed in individuals with BHD. In this article, the skin lesions associated with this condition are reviewed, lung and renal manifestations associated with this syndrome are presented, and malignancies occurring in these patients are summarized.
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23
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Schmidt LS, Linehan WM. FLCN: The causative gene for Birt-Hogg-Dubé syndrome. Gene 2018; 640:28-42. [PMID: 28970150 PMCID: PMC5682220 DOI: 10.1016/j.gene.2017.09.044] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/11/2017] [Accepted: 09/21/2017] [Indexed: 01/30/2023]
Abstract
Germline mutations in the novel tumor suppressor gene FLCN are responsible for the autosomal dominant inherited disorder Birt-Hogg-Dubé (BHD) syndrome that predisposes to fibrofolliculomas, lung cysts and spontaneous pneumothorax, and an increased risk for developing kidney tumors. Although the encoded protein, folliculin (FLCN), has no sequence homology to known functional domains, x-ray crystallographic studies have shown that the C-terminus of FLCN has structural similarity to DENN (differentially expressed in normal cells and neoplasia) domain proteins that act as guanine nucleotide exchange factors (GEFs) for small Rab GTPases. FLCN forms a complex with folliculin interacting proteins 1 and 2 (FNIP1, FNIP2) and with 5' AMP-activated protein kinase (AMPK). This review summarizes FLCN functional studies which support a role for FLCN in diverse metabolic pathways and cellular processes that include modulation of the mTOR pathway, regulation of PGC1α and mitochondrial biogenesis, cell-cell adhesion and RhoA signaling, control of TFE3/TFEB transcriptional activity, amino acid-dependent activation of mTORC1 on lysosomes through Rag GTPases, and regulation of autophagy. Ongoing research efforts are focused on clarifying the primary FLCN-associated pathway(s) that drives the development of fibrofolliculomas, lung cysts and kidney tumors in BHD patients carrying germline FLCN mutations.
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Affiliation(s)
- Laura S Schmidt
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States; Basic Science Program, Leidos Biomedical Research, Inc., Frederick Laboratory for Cancer Research, Frederick, MD 21702, United States.
| | - W Marston Linehan
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States.
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24
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Pham DL, Trinh TH, Ban GY, Kim SH, Park HS. Epithelial folliculin is involved in airway inflammation in workers exposed to toluene diisocyanate. Exp Mol Med 2017; 49:e395. [PMID: 29147010 PMCID: PMC5704188 DOI: 10.1038/emm.2017.180] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/18/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022] Open
Abstract
Toluene diisocyanate (TDI) exposure can directly activate and damage airway epithelium. Folliculin (FLCN) is a protein expressed by human airway epithelial cells (HAECs) to maintain airway epithelial integrity and survival. This study investigated the involvement of FLCN in the pathogenesis of TDI-induced occupational asthma (OA). Enzyme-linked immunosorbent assay was used to measure serum levels of FLCN in TDI-exposed subjects (93 TDI-OA patients and 119 asymptomatic exposed controls (AEC)), 200 non-occupational asthma (NOA) patients and 71 unexposed healthy normal controls (NCs). Significantly more subjects in the TDI-OA and AEC groups had high serum levels of FLCN compared to those in the NOA group (P=0.002 and P=0.001, respectively), all of which were higher than the NC group (all P<0.001). The serum level of FLCN was positively correlated with TDI exposure duration (r=0.251, P=0.027), but was negatively correlated with asthma duration of TDI-OA patients (r=−0.329, P=0.029). TDI-exposed subjects with high FLCN levels had higher serum levels of total IgE than those with lower levels. The effects of TDI exposure on FLCN production was investigated by treating HAECs (A549 cells) with TDI-human serum albumin conjugate, which showed increased expression and release of FLCN and interleukin-8 from HAECs. Co-culture with peripheral blood neutrophils also induced FLCN expression and release from HAECs. In conclusion, TDI exposure and TDI-induced neutrophil recruitment into the airways can activate and stimulate HAECs to produce FLCN, which could be involved in airway inflammation in workers exposed to TDI.
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Affiliation(s)
- Duy L Pham
- Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, South Korea.,Department of Biomedical Sciences, The Graduate School, Ajou University, Suwon, South Korea.,Department of Physiology, Faculty of Medicine, University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam
| | - Tu Hk Trinh
- Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, South Korea
| | - Ga-Young Ban
- Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, South Korea
| | - Seung-Hyun Kim
- Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, South Korea
| | - Hae-Sim Park
- Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, South Korea.,Department of Biomedical Sciences, The Graduate School, Ajou University, Suwon, South Korea
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Abstract
OBJECTIVE Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant inherited syndrome involving multiple organs. In young patients, renal neoplasms that are multiple, bilateral, or both, such as oncocytomas, chromophobe renal cell carcinoma (RCC), hybrid chromophobe RCC-oncocytomas, clear cell RCC, and papillary RCC, can suggest BHD syndrome. Extrarenal findings, including dermal lesions, pulmonary cysts, and spontaneous pneumothoraces, also aid in diagnosis. CONCLUSION Radiologists may be one of the first medical specialists to suggest the diagnosis of BHD syndrome. Knowledge of pathogenesis and management, including the importance of the types of renal neoplasms in a given patient, is needed to properly recognize this rare condition.
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Zheng J, Duan B, Sun S, Cui J, Du J, Zhang Y. Folliculin Interacts with Rab35 to Regulate EGF-Induced EGFR Degradation. Front Pharmacol 2017; 8:688. [PMID: 29018350 PMCID: PMC5622982 DOI: 10.3389/fphar.2017.00688] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/14/2017] [Indexed: 12/20/2022] Open
Abstract
Aims and Hypothesis: This study aims to investigate the mechanism involved in intracellular regulation of EGFR degradation induced by EGF. Methods: Phosphorylation of proteins related to EGFR signaling was examined by western blot analysis. Activation, connection between Rab35 and folliculin (FLCN) were assessed by pulldown, coimmunoprecipitation assays separately. The relationship between FLCN and cell growth was detected using gene overexpression and knock-down techniques. Results: Here, we demonstrate that interfering with FLCN, a tumor suppressor, reduces the rate of EGF-induced EGFR degradation, resulting in prolonged activation of downstream signaling. Rab35 is also involved in these processes. Moreover, C-terminal of FLCN binds to and activates Rab35. Of special interest is the observation that erlotinib, a selective EGFR inhibitor, not only obstructs the EGFR-mediated cellular signaling, but also abolishes EGF-stimulated EGFR degradation. Further results reveal that EGF facilitates the activation of Rab35, and FLCN modulates EGF-dependent Rab35 activation and cell growth. Conclusions: Taken together, our study proposes a negative-feedback regulation model in which FLCN mediates EGF-induced Rab35 activation, thereby increasing EGFR degradation and attenuating EGFR signaling.
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Affiliation(s)
- Jianchao Zheng
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Biao Duan
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Shixiu Sun
- Department of Physiology, Nanjing Medical University, Nanjing, China.,Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China
| | - Jie Cui
- Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China.,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, China
| | - Jun Du
- Department of Physiology, Nanjing Medical University, Nanjing, China.,Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China
| | - Yujie Zhang
- Department of Physiology, Nanjing Medical University, Nanjing, China.,Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Personalized Medicine, Nanjing Medical University, Nanjing, China
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27
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Bartram MP, Mishra T, Reintjes N, Fabretti F, Gharbi H, Adam AC, Göbel H, Franke M, Schermer B, Haneder S, Benzing T, Beck BB, Müller RU. Characterization of a splice-site mutation in the tumor suppressor gene FLCN associated with renal cancer. BMC MEDICAL GENETICS 2017; 18:53. [PMID: 28499369 PMCID: PMC5429543 DOI: 10.1186/s12881-017-0416-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 05/04/2017] [Indexed: 01/24/2023]
Abstract
Background Renal cell carcinoma is among the most prevalent malignancies. It is generally sporadic. However, genetic studies of rare familial forms have led to the identification of mutations in causative genes such as VHL and FLCN. Mutations in the FLCN gene are the cause of Birt-Hogg-Dubé syndrome, a rare tumor syndrome which is characterized by the combination of renal cell carcinoma, pneumothorax and skin tumors. Methods Using Sanger sequencing we identify a heterozygous splice-site mutation in FLCN in lymphocyte DNA of a patient suffering from renal cell carcinoma. Furthermore, both tumor DNA and DNA from a metastasis are analyzed regarding this mutation. The pathogenic effect of the sequence alteration is confirmed by minigene assays and the biochemical consequences on the protein are examined using TALEN-mediated transgenesis in cultured cells. Results Here we describe an FLCN mutation in a 55-year-old patient who presented himself with progressive weight loss, bilateral kidney cysts and renal tumors. He and members of his family had a history of recurrent pneumothorax during the last few decades. Histology after tumor nephrectomy showed a mixed kidney cancer consisting of elements of a chromophobe renal cell carcinoma and dedifferentiated small cell carcinoma component. Subsequent FLCN sequencing identified an intronic c.1177-5_-3delCTC alteration that most likely affected the correct splicing of exon 11 of the FLCN gene. We demonstrate skipping of exon 11 to be the consequence of this mutation leading to a shift in the reading frame and the insertion of a premature stop codon. Interestingly, the truncated protein was still expressed both in cell culture and in tumor tissue, though it was strongly destabilized and its subcellular localization differed from wild-type FLCN. Both, altered protein stability and subcellular localization could be partly reversed by blocking proteasomal and lysosomal degradation. Conclusions Identification of disease-causing mutations in BHD syndrome requires the analysis of intronic sequences. However, biochemical validation of the consecutive alterations of the resulting protein is especially important in these cases. Functional characterization of the disease-causing mutations in BHD syndrome may guide further research for the development of novel diagnostic and therapeutic strategies. Electronic supplementary material The online version of this article (doi:10.1186/s12881-017-0416-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Malte P Bartram
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Tripti Mishra
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Nadine Reintjes
- Institute of Human Genetics, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Francesca Fabretti
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Hakam Gharbi
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Alexander C Adam
- Department of Pathology, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Heike Göbel
- Department of Pathology, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Mareike Franke
- Department of Radiology, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Dr. Hancken Clinic, Harsefelder Str. 8, 21680, Stade, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Stefan Haneder
- Department of Radiology, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Bodo B Beck
- Institute of Human Genetics, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Roman-Ulrich Müller
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Kerpener Str. 62, 50937, Cologne, Germany. .,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany. .,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany.
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28
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Korobeynikov V, Deneka AY, Golemis EA. Mechanisms for nonmitotic activation of Aurora-A at cilia. Biochem Soc Trans 2017; 45:37-49. [PMID: 28202658 PMCID: PMC5860652 DOI: 10.1042/bst20160142] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 10/19/2016] [Accepted: 10/24/2016] [Indexed: 12/12/2022]
Abstract
Overexpression of the Aurora kinase A (AURKA) is oncogenic in many tumors. Many studies of AURKA have focused on activities of this kinase in mitosis, and elucidated the mechanisms by which AURKA activity is induced at the G2/M boundary through interactions with proteins such as TPX2 and NEDD9. These studies have informed the development of small molecule inhibitors of AURKA, of which a number are currently under preclinical and clinical assessment. While the first activities defined for AURKA were its control of centrosomal maturation and organization of the mitotic spindle, an increasing number of studies over the past decade have recognized a separate biological function of AURKA, in controlling disassembly of the primary cilium, a small organelle protruding from the cell surface that serves as a signaling platform. Importantly, these activities require activation of AURKA in early G1, and the mechanisms of activation are much less well defined than those in mitosis. A better understanding of the control of AURKA activity and the role of AURKA at cilia are both important in optimizing the efficacy and interpreting potential downstream consequences of AURKA inhibitors in the clinic. We here provide a current overview of proteins and mechanisms that have been defined as activating AURKA in G1, based on the study of ciliary disassembly.
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Affiliation(s)
- Vladislav Korobeynikov
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, U.S.A
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, U.S.A
| | - Alexander Y Deneka
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, U.S.A
- Kazan Federal University, Kazan 420000, Russian Federation
| | - Erica A Golemis
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, U.S.A.
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29
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Abstract
Primary cilia are small, antenna-like structures that detect mechanical and chemical cues and transduce extracellular signals. While mammalian primary cilia were first reported in the late 1800s, scientific interest in these sensory organelles has burgeoned since the beginning of the twenty-first century with recognition that primary cilia are essential to human health. Among the most common clinical manifestations of ciliary dysfunction are renal cysts. The molecular mechanisms underlying renal cystogenesis are complex, involving multiple aberrant cellular processes and signaling pathways, while initiating molecular events remain undefined. Autosomal Dominant Polycystic Kidney Disease is the most common renal cystic disease, caused by disruption of polycystin-1 and polycystin-2 transmembrane proteins, which evidence suggests must localize to primary cilia for proper function. To understand how the absence of these proteins in primary cilia may be remediated, we review intracellular trafficking of polycystins to the primary cilium. We also examine the controversial mechanisms by which primary cilia transduce flow-mediated mechanical stress into intracellular calcium. Further, to better understand ciliary function in the kidney, we highlight the LKB1/AMPK, Wnt, and Hedgehog developmental signaling pathways mediated by primary cilia and misregulated in renal cystic disease.
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30
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Pacitto A, Ascher DB, Wong LH, Blaszczyk BK, Nookala RK, Zhang N, Dokudovskaya S, Levine TP, Blundell TL. Lst4, the yeast Fnip1/2 orthologue, is a DENN-family protein. Open Biol 2016; 5:150174. [PMID: 26631379 PMCID: PMC4703059 DOI: 10.1098/rsob.150174] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The folliculin/Fnip complex has been demonstrated to play a crucial role in the mechanisms underlying Birt–Hogg–Dubé (BHD) syndrome, a rare inherited cancer syndrome. Lst4 has been previously proposed to be the Fnip1/2 orthologue in yeast and therefore a member of the DENN family. In order to confirm this, we solved the crystal structure of the N-terminal region of Lst4 from Kluyveromyces lactis and show it contains a longin domain, the first domain of the full DENN module. Furthermore, we demonstrate that Lst4 through its DENN domain interacts with Lst7, the yeast folliculin orthologue. Like its human counterpart, the Lst7/Lst4 complex relocates to the vacuolar membrane in response to nutrient starvation, most notably in carbon starvation. Finally, we express and purify the recombinant Lst7/Lst4 complex and show that it exists as a 1 : 1 heterodimer in solution. This work confirms the membership of Lst4 and the Fnip proteins in the DENN family, and provides a basis for using the Lst7/Lst4 complex to understand the molecular function of folliculin and its role in the pathogenesis of BHD syndrome.
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Affiliation(s)
- Angela Pacitto
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - David B Ascher
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Louise H Wong
- Department of Cell Biology, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Beata K Blaszczyk
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Ravi K Nookala
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Nianshu Zhang
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Svetlana Dokudovskaya
- CNRS UMR 8126, Université Paris-Sud 11, Institut Gustave Roussy, 114, rue Edouard Vaillant, Villejuif 94805, France
| | - Tim P Levine
- Department of Cell Biology, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
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31
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Kenyon EJ, Luijten MNH, Gill H, Li N, Rawlings M, Bull JC, Hadzhiev Y, van Steensel MAM, Maher E, Mueller F. Expression and knockdown of zebrafish folliculin suggests requirement for embryonic brain morphogenesis. BMC DEVELOPMENTAL BIOLOGY 2016; 16:23. [PMID: 27391801 PMCID: PMC4939010 DOI: 10.1186/s12861-016-0119-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 05/15/2016] [Indexed: 12/27/2022]
Abstract
Background Birt-Hogg-Dubé syndrome (BHD) is a dominantly inherited familial cancer syndrome characterised by the development of benign skin fibrofolliculomas, multiple lung and kidney cysts, spontaneous pneumothorax and susceptibility to renal cell carcinoma. BHD is caused by mutations in the gene encoding Folliculin (FLCN). Little is known about what FLCN does in a healthy individual and how best to treat those with BHD. As a first approach to developing a vertebrate model for BHD we aimed to identify the temporal and spatial expression of flcn transcripts in the developing zebrafish embryo. To gain insights into the function of flcn in a whole organism system we generated a loss of function model of flcn by the use of morpholino knockdown in zebrafish. Results flcn is expressed broadly and upregulated in the fin bud, somites, eye and proliferative regions of the brain of the Long-pec stage zebrafish embryos. Together with knockdown phenotypes, expression analysis suggest involvement of flcn in zebrafish embryonic brain development. We have utilised the zFucci system, an in vivo, whole organism cell cycle assay to study the potential role of flcn in brain development. We found that at the 18 somite stage there was a significant drop in cells in the S-M phase of the cell cycle in flcn morpholino injected embryos with a corresponding increase of cells in the G1 phase. This was particularly evident in the brain, retina and somites of the embryo. Timelapse analysis of the head region of flcn morpholino injected and mismatch control embryos shows the temporal dynamics of cell cycle misregulation during development. Conclusions In conclusion we show that zebrafish flcn is expressed in a non-uniform manner and is likely required for the maintenance of correct cell cycle regulation during embryonic development. We demonstrate the utilisation of the zFucci system in testing the role of flcn in cell proliferation and suggest a function for flcn in regulating cell proliferation in vertebrate embryonic brain development. Electronic supplementary material The online version of this article (doi:10.1186/s12861-016-0119-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Emma J Kenyon
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. .,Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton, UK.
| | - Monique N H Luijten
- Department of Dermatology and GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Harmeet Gill
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Nan Li
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Matthew Rawlings
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - James C Bull
- Department of Biosciences, College of Science, Swansea University, Swansea, SA2 8PP, Wales, UK
| | - Yavor Hadzhiev
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Maurice A M van Steensel
- School of Medicine and School of Life Sciences, University of Dundee, Dow Street, Dundee, UK.,Institute of Medical Biology, Immunos, 8A Biomedical Grove, Singapore, Singapore
| | - Eamonn Maher
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Ferenc Mueller
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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32
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Dodding MP. Folliculin - A tumor suppressor at the intersection of metabolic signaling and membrane traffic. Small GTPases 2016; 8:100-105. [PMID: 27355777 DOI: 10.1080/21541248.2016.1204808] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The Birt-Hoge-Dubé syndrome tumor suppressor Folliculin is a regulator of metabolism and has as a wide range of cellular and organismal phenotypes associated with its disruption. However, the molecular mechanisms which underlie its functions are poorly understood. Folliculin has been described to associate with lysosomes in response to nutrient depletion and form a key part of the signaling network that controls the activity of mTORC1. We recently reported that Folliculin can control the nutrient dependent cytoplasmic distribution of lysosomes by promoting the formation of a complex with the Golgi-associated small GTPase Rab34 and its effector RILP. We thus define a mechanistic connection between the lysosomal nutrient signaling network and the transport machinery that controls the distribution and dynamics of this organelle. Here we summarise the main conclusions from that study, attempt to integrate our findings with other recent studies on lysosome distribution/dynamics, and discuss the potential consequences of the dysregulation of this processes caused by Folliculin loss for Birt-Hoge-Dubé syndrome and normal cell function.
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Affiliation(s)
- Mark P Dodding
- a Randall Division of Cell and Molecular Biophysics , King's College London , London , UK
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33
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FLCN Maintains the Leucine Level in Lysosome to Stimulate mTORC1. PLoS One 2016; 11:e0157100. [PMID: 27280402 PMCID: PMC4900541 DOI: 10.1371/journal.pone.0157100] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 05/24/2016] [Indexed: 01/09/2023] Open
Abstract
The intracellular amino acid pool within lysosome is a signal that stimulates the nutrient-sensing mTORC1 signalling pathway. The signal transduction cascade has garnered much attention, but little is known about the sequestration of the signalling molecules within the lysosome. Using human HEK293 cells as a model, we found that suppression of the BHD syndrome gene FLCN reduced the leucine level in lysosome, which correlated with decreased mTORC1 activity. Both consequences could be reversed by supplementation with high levels of leucine, but not other tested amino acids. Conversely, overexpressed FLCN could sequester lysosomal leucine and stimulate mTORC1 in an amino acid limitation environment. These results identify a novel function of FLCN: it controls mTORC1 by modulating the leucine signal in lysosome. Furthermore, we provided evidence that FLCN exerted this role by inhibiting the accumulation of the amino acid transporter PAT1 on the lysosome surface, thereby maintaining the signal level within the organelle.
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34
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Sánchez A, Urrego D, Pardo LA. Cyclic expression of the voltage-gated potassium channel KV10.1 promotes disassembly of the primary cilium. EMBO Rep 2016; 17:708-23. [PMID: 27113750 PMCID: PMC5341513 DOI: 10.15252/embr.201541082] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 03/03/2016] [Accepted: 03/09/2016] [Indexed: 12/19/2022] Open
Abstract
The primary cilium, critical for morphogenic and growth factor signaling, is assembled upon cell cycle exit, but the links between ciliogenesis and cell cycle progression are unclear. KV10.1 is a voltage-gated potassium channel frequently overexpressed in tumors. We have previously reported that expression of KV10.1 is temporally restricted to a time period immediately prior to mitosis in healthy cells. Here, we provide microscopical and biochemical evidence that KV10.1 localizes to the centrosome and the primary cilium and promotes ciliary disassembly. Interference with KV10.1 ciliary localization abolishes not only the effects on ciliary disassembly, but also KV10.1-induced tumor progression in vivo Conversely, upon knockdown of KV10.1, ciliary disassembly is impaired, proliferation is delayed, and proliferating cells show prominent primary cilia. Thus, modulation of ciliogenesis by KV10.1 can explain the influence of KV10.1 expression on the proliferation of normal cells and is likely to be a major mechanism underlying its tumorigenic effects.
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Affiliation(s)
- Araceli Sánchez
- Oncophysiology Group, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Diana Urrego
- Oncophysiology Group, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Luis A Pardo
- Oncophysiology Group, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
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35
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Starling GP, Yip YY, Sanger A, Morton PE, Eden ER, Dodding MP. Folliculin directs the formation of a Rab34-RILP complex to control the nutrient-dependent dynamic distribution of lysosomes. EMBO Rep 2016; 17:823-41. [PMID: 27113757 PMCID: PMC4893818 DOI: 10.15252/embr.201541382] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 03/14/2016] [Indexed: 11/09/2022] Open
Abstract
The spatial distribution of lysosomes is important for their function and is, in part, controlled by cellular nutrient status. Here, we show that the lysosome associated Birt-Hoge-Dubé (BHD) syndrome renal tumour suppressor folliculin (FLCN) regulates this process. FLCN promotes the peri-nuclear clustering of lysosomes following serum and amino acid withdrawal and is supported by the predominantly Golgi-associated small GTPase Rab34. Rab34-positive peri-nuclear membranes contact lysosomes and cause a reduction in lysosome motility and knockdown of FLCN inhibits Rab34-induced peri-nuclear lysosome clustering. FLCN interacts directly via its C-terminal DENN domain with the Rab34 effector RILP Using purified recombinant proteins, we show that the FLCN-DENN domain does not act as a GEF for Rab34, but rather, loads active Rab34 onto RILP We propose a model whereby starvation-induced FLCN association with lysosomes drives the formation of contact sites between lysosomes and Rab34-positive peri-nuclear membranes that restrict lysosome motility and thus promote their retention in this region of the cell.
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Affiliation(s)
- Georgina P Starling
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - Yan Y Yip
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - Anneri Sanger
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - Penny E Morton
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - Emily R Eden
- Institute of Ophthalmology, University College London, London, UK
| | - Mark P Dodding
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
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36
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Zhong M, Zhao X, Li J, Yuan W, Yan G, Tong M, Guo S, Zhu Y, Jiang Y, Liu Y, Jiang Y. Tumor Suppressor Folliculin Regulates mTORC1 through Primary Cilia. J Biol Chem 2016; 291:11689-97. [PMID: 27072130 DOI: 10.1074/jbc.m116.719997] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Indexed: 12/18/2022] Open
Abstract
Folliculin (FLCN) is the tumor suppressor associated with Birt-Hogg-Dubé (BHD) syndrome that predisposes patients to incident of hamartomas and cysts in multiple organs. Its inactivation causes deregulation in the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway. However, the underlying mechanism is poorly defined. In this study, we show that FLCN is a ciliary protein that functions through primary cilia to regulate mTORC1. In response to flow stress, FLCN associates with LKB1 and recruits the kinase to primary cilia for activation of AMPK resided at basal bodies, which causes mTORC1 down-regulation. In cells depleted of FLCN, LKB1 fails to accumulate in primary cilia and AMPK at the basal bodies remains inactive, thus nullifying the inhibitory effect of flow stress on mTORC1 activity. Our results demonstrate that FLCN is part of a flow sensory mechanism that regulates mTORC1 through primary cilia.
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Affiliation(s)
- Mingming Zhong
- From the Guangdong Provincial Key Laboratory of Proteomics; Key laboratory of Transcriptomics and Proteomics of Ministry of Education of China, State Key Laboratory of Organ Failure Research, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Xuwen Zhao
- From the Guangdong Provincial Key Laboratory of Proteomics; Key laboratory of Transcriptomics and Proteomics of Ministry of Education of China, State Key Laboratory of Organ Failure Research, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Jinmei Li
- From the Guangdong Provincial Key Laboratory of Proteomics; Key laboratory of Transcriptomics and Proteomics of Ministry of Education of China, State Key Laboratory of Organ Failure Research, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Wenjie Yuan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Gonghong Yan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Mingming Tong
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Shuguang Guo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
| | - Yichao Zhu
- Department of Physiology, Nanjing Medical University, Nanjing 211166, China
| | - Yong Jiang
- From the Guangdong Provincial Key Laboratory of Proteomics; Key laboratory of Transcriptomics and Proteomics of Ministry of Education of China, State Key Laboratory of Organ Failure Research, Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China,
| | - Yongjian Liu
- Department of Physiology, Nanjing Medical University, Nanjing 211166, China
| | - Yu Jiang
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261 and
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Tosoni K, Cassidy D, Kerr B, Land SC, Mehta A. Using Drugs to Probe the Variability of Trans-Epithelial Airway Resistance. PLoS One 2016; 11:e0149550. [PMID: 26926476 PMCID: PMC4771809 DOI: 10.1371/journal.pone.0149550] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 02/02/2016] [Indexed: 12/15/2022] Open
Abstract
Background Precision medicine aims to combat the variability of the therapeutic response to a given medicine by delivering the right medicine to the right patient. However, the application of precision medicine is predicated on a prior quantitation of the variance of the reference range of normality. Airway pathophysiology provides a good example due to a very variable first line of defence against airborne assault. Humans differ in their susceptibility to inhaled pollutants and pathogens in part due to the magnitude of trans-epithelial resistance that determines the degree of epithelial penetration to the submucosal space. This initial ‘set-point’ may drive a sentinel event in airway disease pathogenesis. Epithelia differentiated in vitro from airway biopsies are commonly used to model trans-epithelial resistance but the ‘reference range of normality’ remains problematic. We investigated the range of electrophysiological characteristics of human airway epithelia grown at air-liquid interface in vitro from healthy volunteers focusing on the inter- and intra-subject variability both at baseline and after sequential exposure to drugs modulating ion transport. Methodology/Principal Findings Brushed nasal airway epithelial cells were differentiated at air-liquid interface generating 137 pseudostratified ciliated epithelia from 18 donors. A positively-skewed baseline range exists for trans-epithelial resistance (Min/Max: 309/2963 Ω·cm2), trans-epithelial voltage (-62.3/-1.8 mV) and calculated equivalent current (-125.0/-3.2 μA/cm2; all non-normal, P<0.001). A minority of healthy humans manifest a dramatic amiloride sensitivity to voltage and trans-epithelial resistance that is further discriminated by prior modulation of cAMP-stimulated chloride transport. Conclusions/Significance Healthy epithelia show log-order differences in their ion transport characteristics, likely reflective of their initial set-points of basal trans-epithelial resistance and sodium transport. Our data may guide the choice of the background set point in subjects with airway diseases and frame the reference range for the future delivery of precision airway medicine.
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Affiliation(s)
- Kendra Tosoni
- Division of Cardiovascular and Diabetes Medicine, University of Dundee, Medical Research Institute Ninewells Hospital and Medical School, Dundee, Scotland, United Kingdom
- * E-mail: (AM); (KT)
| | - Diane Cassidy
- Division of Cardiovascular and Diabetes Medicine, University of Dundee, Medical Research Institute Ninewells Hospital and Medical School, Dundee, Scotland, United Kingdom
| | - Barry Kerr
- School of Medicine, University of Dundee, Dundee, Scotland, United Kingdom
| | - Stephen C. Land
- Division of Cardiovascular and Diabetes Medicine, University of Dundee, Medical Research Institute Ninewells Hospital and Medical School, Dundee, Scotland, United Kingdom
| | - Anil Mehta
- Division of Cardiovascular and Diabetes Medicine, University of Dundee, Medical Research Institute Ninewells Hospital and Medical School, Dundee, Scotland, United Kingdom
- * E-mail: (AM); (KT)
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Mechanisms of pulmonary cyst pathogenesis in Birt-Hogg-Dube syndrome: The stretch hypothesis. Semin Cell Dev Biol 2016; 52:47-52. [PMID: 26877139 DOI: 10.1016/j.semcdb.2016.02.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/04/2016] [Accepted: 02/08/2016] [Indexed: 12/11/2022]
Abstract
Loss-of-function mutations in the folliculin gene (FLCN) on chromosome 17p cause Birt-Hogg-Dube syndrome (BHD), which is associated with cystic lung disease. The risk of lung collapse (pneumothorax) in BHD patients is 50-fold higher than in the general population. The cystic lung disease in BHD is distinctive because the cysts tend to be basilar, subpleural and lentiform, differentiating BHD from most other cystic lung diseases. Recently, major advances in elucidating the primary functions of the folliculin protein have been made, including roles in mTOR and AMPK signaling via the interaction of FLCN with FNIP1/2, and cell-cell adhesion via the physical interaction of FLCN with plakophilin 4 (PKP4), an armadillo-repeat containing protein that interacts with E-cadherin and is a component of the adherens junctions. In addition, in just the last three years, the pulmonary impact of FLCN deficiency has been examined for the first time. In mouse models, evidence has emerged that AMPK signaling and cell-cell adhesion are involved in alveolar enlargement. In addition, the pathologic features of human BHD cysts have been recently comprehensively characterized. The "stretch hypothesis" proposes that cysts in BHD arise because of fundamental defects in cell-cell adhesion, leading to repeated respiration-induced physical stretch-induced stress and, over time, expansion of alveolar spaces particularly in regions of the lung with larger changes in alveolar volume and at weaker "anchor points" to the pleura. This hypothesis ties together many of the new data from cellular and mouse models of BHD and from the human pathologic studies. Critical questions remain. These include whether the consequences of stretch-induced cyst formation arise through a destructive/inflammatory program or a proliferative program (or both), whether cyst initiation involves a "second hit" genetic event inactivating the remaining wild-type copy of FLCN (as is known to occur in BHD-associated renal cell carcinomas), and whether cyst initiation involves exclusively the epithelial compartment versus an interaction between the epithelium and mesenchyme. Ultimately, understanding the mechanisms of cystic lung disease in BHD may help to elucidate the pathogenesis of primary spontaneous pneumothorax, with more than 20,000 cases reported annually in the United States alone.
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Slaats GG, Wheway G, Foletto V, Szymanska K, van Balkom BWM, Logister I, Den Ouden K, Keijzer-Veen MG, Lilien MR, Knoers NV, Johnson CA, Giles RH. Screen-based identification and validation of four new ion channels as regulators of renal ciliogenesis. J Cell Sci 2015; 128:4550-9. [PMID: 26546361 DOI: 10.1242/jcs.176065] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 11/04/2015] [Indexed: 01/04/2023] Open
Abstract
To investigate the contribution of ion channels to ciliogenesis, we carried out a small interfering RNA (siRNA)-based reverse genetics screen of all ion channels in the mouse genome in murine inner medullary collecting duct kidney cells. This screen revealed four candidate ion channel genes: Kcnq1, Kcnj10, Kcnf1 and Clcn4. We show that these four ion channels localize to renal tubules, specifically to the base of primary cilia. We report that human KCNQ1 Long QT syndrome disease alleles regulate renal ciliogenesis; KCNQ1-p.R518X, -p.A178T and -p.K362R could not rescue ciliogenesis after Kcnq1-siRNA-mediated depletion in contrast to wild-type KCNQ1 and benign KCNQ1-p.R518Q, suggesting that the ion channel function of KCNQ1 regulates ciliogenesis. In contrast, we demonstrate that the ion channel function of KCNJ10 is independent of its effect on ciliogenesis. Our data suggest that these four ion channels regulate renal ciliogenesis through the periciliary diffusion barrier or the ciliary pocket, with potential implication as genetic contributors to ciliopathy pathophysiology. The new functional roles of a subset of ion channels provide new insights into the disease pathogenesis of channelopathies, which might suggest future therapeutic approaches.
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Affiliation(s)
- Gisela G Slaats
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
| | - Gabrielle Wheway
- Section of Ophthalmology and Neuroscience, Leeds Institutes of Molecular Medicine, University of Leeds, Leeds LS9 7TF, UK
| | - Veronica Foletto
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
| | - Katarzyna Szymanska
- Section of Ophthalmology and Neuroscience, Leeds Institutes of Molecular Medicine, University of Leeds, Leeds LS9 7TF, UK
| | - Bas W M van Balkom
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
| | - Ive Logister
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
| | - Krista Den Ouden
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
| | - Mandy G Keijzer-Veen
- Department of Pediatric Nephrology, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
| | - Marc R Lilien
- Department of Pediatric Nephrology, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
| | - Nine V Knoers
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
| | - Colin A Johnson
- Section of Ophthalmology and Neuroscience, Leeds Institutes of Molecular Medicine, University of Leeds, Leeds LS9 7TF, UK
| | - Rachel H Giles
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
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Vertii A, Bright A, Delaval B, Hehnly H, Doxsey S. New frontiers: discovering cilia-independent functions of cilia proteins. EMBO Rep 2015; 16:1275-87. [PMID: 26358956 DOI: 10.15252/embr.201540632] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/17/2015] [Indexed: 12/11/2022] Open
Abstract
In most vertebrates, mitotic spindles and primary cilia arise from a common origin, the centrosome. In non-cycling cells, the centrosome is the template for primary cilia assembly and, thus, is crucial for their associated sensory and signaling functions. During mitosis, the duplicated centrosomes mature into spindle poles, which orchestrate mitotic spindle assembly, chromosome segregation, and orientation of the cell division axis. Intriguingly, both cilia and spindle poles are centrosome-based, functionally distinct structures that require the action of microtubule-mediated, motor-driven transport for their assembly. Cilia proteins have been found at non-cilia sites, where they have distinct functions, illustrating a diverse and growing list of cellular processes and structures that utilize cilia proteins for crucial functions. In this review, we discuss cilia-independent functions of cilia proteins and re-evaluate their potential contributions to "cilia" disorders.
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Affiliation(s)
- Anastassiia Vertii
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Alison Bright
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | | | - Heidi Hehnly
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Stephen Doxsey
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
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41
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Park F. Accessory proteins for heterotrimeric G-proteins in the kidney. Front Physiol 2015; 6:219. [PMID: 26300785 PMCID: PMC4528294 DOI: 10.3389/fphys.2015.00219] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 07/20/2015] [Indexed: 11/17/2022] Open
Abstract
Heterotrimeric G-proteins play a fundamentally important role in regulating signal transduction pathways in the kidney. Accessory proteins are being identified as direct binding partners for heterotrimeric G-protein α or βγ subunits to promote more diverse mechanisms by which G-protein signaling is controlled. In some instances, accessory proteins can modulate the signaling magnitude, localization, and duration following the activation of cell membrane-associated receptors. Alternatively, accessory proteins complexed with their G-protein α or βγ subunits can promote non-canonical models of signaling activity within the cell. In this review, we will highlight the expression profile, localization and functional importance of these newly identified accessory proteins to control the function of select G-protein subunits under normal and various disease conditions observed in the kidney.
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Affiliation(s)
- Frank Park
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center Memphis, TN, USA
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42
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Fogel AL, Hill S, Teng JMC. Advances in the therapeutic use of mammalian target of rapamycin (mTOR) inhibitors in dermatology. J Am Acad Dermatol 2015; 72:879-89. [PMID: 25769191 DOI: 10.1016/j.jaad.2015.01.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 01/07/2015] [Accepted: 01/09/2015] [Indexed: 12/31/2022]
Abstract
Significant developments in the use of mammalian target of rapamycin (mTOR) inhibitors (mTORIs) as immunosuppressant and antiproliferative agents have been made. Recent advances in the understanding of the mTOR signaling pathway and its downstream effects on tumorigenesis and vascular proliferation have broadened the clinical applications of mTORIs in many challenging disorders such as tuberous sclerosis complex, pachyonychia congenita, complex vascular anomalies, and inflammatory dermatoses. Systemic mTORI therapy has shown benefits in these areas, but is associated with significant side effects that sometimes necessitate drug holidays. To mitigate the side effects of systemic mTORIs for dermatologic applications, preliminary work to assess the potential of percutaneous therapy has been performed, and the evidence suggests that percutaneous delivery of mTORIs may allow for effective long-term therapy while avoiding systemic toxicities. Additional large placebo-controlled, double-blinded, randomized studies are needed to assess the efficacy, safety, duration, and tolerability of topical treatments. The objective of this review is to provide updated information on the novel use of mTORIs in the management of many cutaneous disorders.
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Affiliation(s)
| | | | - Joyce M C Teng
- Dermatology, Stanford University School of Medicine, Palo Alto, California; Pediatrics, Stanford University School of Medicine, Palo Alto, California; Pediatric Dermatology, Stanford University School of Medicine, Palo Alto, California; Stanford University School of Medicine, Palo Alto, California.
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43
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Tellkamp F, Vorhagen S, Niessen CM. Epidermal polarity genes in health and disease. Cold Spring Harb Perspect Med 2014; 4:a015255. [PMID: 25452423 DOI: 10.1101/cshperspect.a015255] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The epidermis of the skin is a highly polarized, metabolic tissue with important innate immune functions. The polarity of the epidermis is, for example, reflected in controlled changes in cell shape that accompany differentiation, oriented cell division, and the planar orientation of hair follicles and cilia. The establishment and maintenance of polarity is organized by a diverse set of polarity proteins that include transmembrane adhesion proteins, cytoskeletal scaffold proteins, and kinases. Although polarity proteins have been extensively studied in cell culture and in vivo in simple epithelia of lower organisms, their role in mammalian tissue biology is only slowly evolving. This article will address the importance of polarizing processes and their molecular regulators in epidermal morphogenesis and homeostasis and discuss how alterations in polarity may contribute to skin disease.
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Affiliation(s)
- Frederik Tellkamp
- Department of Dermatology, Center for Molecular Medicine Cologne, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Susanne Vorhagen
- Department of Dermatology, Center for Molecular Medicine Cologne, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Carien M Niessen
- Department of Dermatology, Center for Molecular Medicine Cologne, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
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Schmidt LS, Linehan WM. Clinical Features, Genetics and Potential Therapeutic Approaches for Birt-Hogg-Dubé Syndrome. Expert Opin Orphan Drugs 2014; 3:15-29. [PMID: 26581862 PMCID: PMC4646088 DOI: 10.1517/21678707.2014.987124] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant disorder that predisposes to fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax and renal neoplasia. BHD is characterized by germline mutations in tumor suppressor FLCN. Inactivation of the remaining FLCN allele in kidney cells drives tumorigenesis. Novel FLCN-interacting proteins, FNIP1 and FNIP2, were identified. Studies with FLCN-deficient in vitro and in vivo models support a role for FLCN in modulating AKT-mTOR signaling. Emerging evidence suggests that FLCN may interact in a number of pathways/processes. Identification of FLCN's major functional roles will provide the basis for developing targeted therapies for BHD patients. AREAS COVERED This review covers BHD diagnostic criteria, clinical manifestations and genetics, as well as molecular consequences of FLCN inactivation. Recommended surveillance practices, patient management, and potential therapeutic options are discussed. EXPERT OPINION In the decade since FLCN was identified as causative for BHD, we have gained a greater understanding of the clinical spectrum and genetics of this cancer syndrome. Recent studies have identified interactions between FLCN and a variety of signaling pathways and cellular processes, notably AKT-mTOR. Currently, surgical intervention is the only available therapy for BHD-associated renal tumors. Effective therapies will need to target primary pathways/processes deregulated in FLCN-deficient renal tumors and fibrofolliculomas.
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Affiliation(s)
- Laura S. Schmidt
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892
| | - W. Marston Linehan
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892
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The ciliopathy gene Rpgrip1l is essential for hair follicle development. J Invest Dermatol 2014; 135:701-709. [PMID: 25398052 PMCID: PMC4340706 DOI: 10.1038/jid.2014.483] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 10/27/2014] [Accepted: 10/27/2014] [Indexed: 01/01/2023]
Abstract
The primary cilium is essential for skin morphogenesis through regulating the Notch, Wnt, and hedgehog signaling pathways. Prior studies on the functions of primary cilia in the skin were based on the investigations of genes that are essential for cilium formation. However, none of these ciliogenic genes has been linked to ciliopathy, a group of disorders caused by abnormal formation or function of cilia. To determine whether there is a genetic and molecular link between ciliopathies and skin morphogenesis, we investigated the role of RPGRIP1L, a gene mutated in Joubert (JBTS) and Meckel (MKS) syndromes, two severe forms of ciliopathy, in the context of skin development. We found that RPGRIP1L is essential for hair follicle morphogenesis. Specifically, disrupting the Rpgril1 gene in mice resulted in reduced proliferation and differentiation of follicular keratinocytes, leading to hair follicle developmental defects. These defects were associated with significantly decreased primary cilium formation and attenuated hedgehog signaling. In contrast, we found that hair follicle induction and polarization and the development of interfollicular epidermis were unaffected. This study indicates that RPGRIP1L, a ciliopathy gene, is essential for hair follicle morphogenesis likely through regulating primary cilia formation and the hedgehog signaling pathway.
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3D spheroid model of mIMCD3 cells for studying ciliopathies and renal epithelial disorders. Nat Protoc 2014; 9:2725-31. [PMID: 25356583 DOI: 10.1038/nprot.2014.181] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We have developed a novel 3D cell culture model that uses mouse inner-medullary collecting duct (mIMCD3) cells to generate epithelial spheroids. This model is amenable to efficient siRNA knockdown and subsequent rescue with human patient-derived alleles. Spheroids develop apicobasal polarity and complete lumens, and they are consequently an ideal model for polarity defects seen in renal ciliopathies such as nephronophthisis. Briefly, mIMCD3 cells are transfected and subsequently passaged to a Matrigel mixture, which is seeded in chamber slides and covered in growth medium. Once the spheroids are formed, Matrigel is dissolved and immunocytochemistry is performed in the chamber slides. The technique is amenable to semiautomatic imaging analysis, and it can test multiple genes simultaneously, gene-dosing effects and a variety of therapeutic interventions. The spheroid technique is a unique and simple 6-d in vitro method of interrogating ex vivo tissue organization.
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Abstract
Sebaceous tumors are epithelial tumors with a differentiation towards sebaceous adnexal structures of the skin. They imitate the epithelial cells of mature sebaceous glands, sebaceous ducts, immature (embryonic) sebaceous structures or sebaceous glands that are not stimulated by hormones (mantle structures). This article explains the classification of sebaceous tumors on the basis of the normal histology of sebaceous glands. Clinical and histopathological criteria are given for the most important sebaceous tumors. The differential diagnosis of sebaceoma, sebaceous adenoma and various types of sebaceous carcinoma is emphasized. The importance of a specific diagnosis of adnexal tumors is demonstrated by tumor-associated syndromes with involvement of other organs (e.g., Muir-Torre syndrome and Birt-Hogg-Dubé syndrome). Furthermore, conceptional controversies, problems in differential diagnosis and the impact of immunohistochemical staining in the assessment of sebaceous tumors are considered.
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48
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Khabibullin D, Medvetz DA, Pinilla M, Hariharan V, Li C, Hergrueter A, Laucho Contreras M, Zhang E, Parkhitko A, Yu JJ, Owen CA, Huang H, Baron RM, Henske EP. Folliculin regulates cell-cell adhesion, AMPK, and mTORC1 in a cell-type-specific manner in lung-derived cells. Physiol Rep 2014; 2:2/8/e12107. [PMID: 25121506 PMCID: PMC4246594 DOI: 10.14814/phy2.12107] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Germline loss‐of‐function BHD mutations cause cystic lung disease and hereditary pneumothorax, yet little is known about the impact of BHD mutations in the lung. Folliculin (FLCN), the product of the Birt–Hogg–Dube (BHD) gene, has been linked to altered cell–cell adhesion and to the AMPK and mTORC1 signaling pathways. We found that downregulation of FLCN in human bronchial epithelial (HBE) cells decreased the phosphorylation of ACC, a marker of AMPK activation, while downregulation of FLCN in small airway epithelial (SAEC) cells increased the activity of phospho‐S6, a marker of mTORC1 activation, highlighting the cell type–dependent functions of FLCN. Cell–cell adhesion forces were significantly increased in FLCN‐deficient HBE cells, consistent with prior findings in FLCN‐deficient human kidney‐derived cells. To determine how these altered cell–cell adhesion forces impact the lung, we exposed mice with heterozygous inactivation of Bhd (similarly to humans with germline inactivation of one BHD allele) to mechanical ventilation at high tidal volumes. Bhd+/− mice exhibited a trend (P = 0.08) toward increased elastance after 6 h of ventilation at 24 cc/kg. Our results indicate that FLCN regulates the AMPK and mTORC1 pathways and cell–cell adhesion in a cell type–dependent manner. FLCN deficiency may impact the physiologic response to inflation‐induced mechanical stress, but further investigation is required. We hypothesize that FLCN‐dependent effects on signaling and cellular adhesion contribute to the pathogenesis of cystic lung disease in BHD patients. We found that downregulation of FLCN in human bronchial epithelial (HBE) cells decreased the phosphorylation of ACC, a marker of AMPK activation, while downregulation of FLCN in small airway epithelial (SAEC) cells increased the activity of phospho‐S6, a marker of mTORC1 activation, highlighting the cell type–dependent functions of FLCN. Cell–cell adhesion forces were significantly increased in FLCN‐deficient HBE cells, consistent with prior findings in FLCN‐deficient human kidney‐derived cells. To determine how these altered cell–cell adhesion forces impact the lung, we exposed mice with heterozygous inactivation of Bhd (similarly to humans with germline inactivation of one BHD allele) to mechanical ventilation at high tidal volumes. Bhd+/− mice exhibited a trend (P = 0.08) toward increased elastance after 6 h of ventilation at 24 cc/kg.
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Affiliation(s)
- Damir Khabibullin
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Douglas A Medvetz
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Miguel Pinilla
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Venkatesh Hariharan
- Department of Biomedical Engineering, Columbia University, New York City, New York
| | - Chenggang Li
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Anja Hergrueter
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Maria Laucho Contreras
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Erik Zhang
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Andrey Parkhitko
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Jane J Yu
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Caroline A Owen
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts The Lovelace Respiratory Research Institute, Albuquerque, New Mexico
| | - Hayden Huang
- Department of Biomedical Engineering, Columbia University, New York City, New York
| | - Rebecca M Baron
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
| | - Elizabeth P Henske
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, Massachusetts Harvard Medical School, Boston, Massachusetts
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49
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Dunlop EA, Seifan S, Claessens T, Behrends C, Kamps MA, Rozycka E, Kemp AJ, Nookala RK, Blenis J, Coull BJ, Murray JT, van Steensel MA, Wilkinson S, Tee AR. FLCN, a novel autophagy component, interacts with GABARAP and is regulated by ULK1 phosphorylation. Autophagy 2014; 10:1749-60. [PMID: 25126726 DOI: 10.4161/auto.29640] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Birt-Hogg-Dubé (BHD) syndrome is a rare autosomal dominant condition caused by mutations in the FLCN gene and characterized by benign hair follicle tumors, pneumothorax, and renal cancer. Folliculin (FLCN), the protein product of the FLCN gene, is a poorly characterized tumor suppressor protein, currently linked to multiple cellular pathways. Autophagy maintains cellular homeostasis by removing damaged organelles and macromolecules. Although the autophagy kinase ULK1 drives autophagy, the underlying mechanisms are still being unraveled and few ULK1 substrates have been identified to date. Here, we identify that loss of FLCN moderately impairs basal autophagic flux, while re-expression of FLCN rescues autophagy. We reveal that the FLCN complex is regulated by ULK1 and elucidate 3 novel phosphorylation sites (Ser406, Ser537, and Ser542) within FLCN, which are induced by ULK1 overexpression. In addition, our findings demonstrate that FLCN interacts with a second integral component of the autophagy machinery, GABA(A) receptor-associated protein (GABARAP). The FLCN-GABARAP association is modulated by the presence of either folliculin-interacting protein (FNIP)-1 or FNIP2 and further regulated by ULK1. As observed by elevation of GABARAP, sequestome 1 (SQSTM1) and microtubule-associated protein 1 light chain 3 (MAP1LC3B) in chromophobe and clear cell tumors from a BHD patient, we found that autophagy is impaired in BHD-associated renal tumors. Consequently, this work reveals a novel facet of autophagy regulation by ULK1 and substantially contributes to our understanding of FLCN function by linking it directly to autophagy through GABARAP and ULK1.
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Affiliation(s)
- Elaine A Dunlop
- Institute of Cancer and Genetics, Cardiff University; Heath Park, Cardiff, Wales UK
| | - Sara Seifan
- Institute of Cancer and Genetics, Cardiff University; Heath Park, Cardiff, Wales UK
| | - Tijs Claessens
- Institute of Cancer and Genetics, Cardiff University; Heath Park, Cardiff, Wales UK; Department of Dermatology; GROW School for Oncology and Developmental Biology; Maastricht University Medical Center; Maastricht, Netherlands
| | - Christian Behrends
- Frankfurt Institute for Molecular Life Sciences (FMLS) and Institute of Biochemistry II; Goethe University School of Medicine; Frankfurt, Germany
| | - Miriam Af Kamps
- Department of Dermatology; GROW School for Oncology and Developmental Biology; Maastricht University Medical Center; Maastricht, Netherlands
| | - Ewelina Rozycka
- Centre for Cancer Research and Cell Biology; School of Medicine, Dentistry and Biomedical Science; Queen's University Belfast; Belfast, UK
| | - Alain J Kemp
- Institute of Genetics and Molecular Medicine; Edinburgh Cancer Research UK Centre; University of Edinburgh; Edinburgh, UK
| | - Ravi K Nookala
- Department of Biochemistry; University of Cambridge; Cambridge, UK
| | - John Blenis
- Department of Cell Biology; Harvard Medical School; Boston, MA USA
| | - Barry J Coull
- Department of Dermatology; GROW School for Oncology and Developmental Biology; Maastricht University Medical Center; Maastricht, Netherlands
| | - James T Murray
- Centre for Cancer Research and Cell Biology; School of Medicine, Dentistry and Biomedical Science; Queen's University Belfast; Belfast, UK; Trinity Biomedical Sciences Institute; School of Biochemistry and Immunology; Trinity College; Dublin, Ireland
| | - Maurice Am van Steensel
- Department of Dermatology; GROW School for Oncology and Developmental Biology; Maastricht University Medical Center; Maastricht, Netherlands; Immunos; Institute of Medical Biology; Singapore
| | - Simon Wilkinson
- Institute of Genetics and Molecular Medicine; Edinburgh Cancer Research UK Centre; University of Edinburgh; Edinburgh, UK
| | - Andrew R Tee
- Institute of Cancer and Genetics, Cardiff University; Heath Park, Cardiff, Wales UK
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50
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Renkema KY, Stokman MF, Giles RH, Knoers NVAM. Next-generation sequencing for research and diagnostics in kidney disease. Nat Rev Nephrol 2014; 10:433-44. [PMID: 24914583 DOI: 10.1038/nrneph.2014.95] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The advent of next-generation sequencing technologies has enabled genetic nephrology research to move beyond single gene analysis to the simultaneous investigation of hundreds of genes and entire pathways. These new sequencing approaches have been used to identify and characterize causal factors that underlie inherited heterogeneous kidney diseases such as nephronophthisis and congenital anomalies of the kidney and urinary tract. In this Review, we describe the development of next-generation sequencing in basic and clinical research and discuss the implementation of this novel technology in routine patient management. Widespread use of targeted and nontargeted approaches for gene identification in clinical practice will require consistent phenotyping, appropriate disease modelling and collaborative efforts to combine and integrate data analyses. Next-generation sequencing is an exceptionally promising technique that has the potential to improve the management of patients with inherited kidney diseases. However, identifying the molecular mechanisms that lead to renal developmental disorders and ciliopathies is difficult. A major challenge in the near future will be how best to integrate data obtained using next-generation sequencing with personalized medicine, including use of high-throughput disease modelling as a tool to support the clinical diagnosis of kidney diseases.
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Affiliation(s)
- Kirsten Y Renkema
- Department of Medical Genetics, University Medical Center Utrecht, KC04.048.02, PO Box 85090, Utrecht, 3508 AB, Netherlands
| | - Marijn F Stokman
- Department of Medical Genetics, University Medical Center Utrecht, KC04.048.02, PO Box 85090, Utrecht, 3508 AB, Netherlands
| | - Rachel H Giles
- Department of Nephrology and Hypertension, University Medical Center Utrecht, KC04.048.02, PO Box 85090, Utrecht, 3508 AB, Netherlands
| | - Nine V A M Knoers
- Department of Medical Genetics, University Medical Center Utrecht, KC04.048.02, PO Box 85090, Utrecht, 3508 AB, Netherlands
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