1
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Marom R, Zhang B, Washington ME, Song IW, Burrage LC, Rossi VC, Berrier AS, Lindsey A, Lesinski J, Nonet ML, Chen J, Baldridge D, Silverman GA, Sutton VR, Rosenfeld JA, Tran AA, Hicks MJ, Murdock DR, Dai H, Weis M, Jhangiani SN, Muzny DM, Gibbs RA, Caswell R, Pottinger C, Cilliers D, Stals K, Eyre D, Krakow D, Schedl T, Pak SC, Lee BH. Dominant negative variants in KIF5B cause osteogenesis imperfecta via down regulation of mTOR signaling. PLoS Genet 2023; 19:e1011005. [PMID: 37934770 PMCID: PMC10656020 DOI: 10.1371/journal.pgen.1011005] [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] [Received: 05/29/2023] [Revised: 11/17/2023] [Accepted: 10/03/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND Kinesin motor proteins transport intracellular cargo, including mRNA, proteins, and organelles. Pathogenic variants in kinesin-related genes have been implicated in neurodevelopmental disorders and skeletal dysplasias. We identified de novo, heterozygous variants in KIF5B, encoding a kinesin-1 subunit, in four individuals with osteogenesis imperfecta. The variants cluster within the highly conserved kinesin motor domain and are predicted to interfere with nucleotide binding, although the mechanistic consequences on cell signaling and function are unknown. METHODS To understand the in vivo genetic mechanism of KIF5B variants, we modeled the p.Thr87Ile variant that was found in two patients in the C. elegans ortholog, unc-116, at the corresponding position (Thr90Ile) by CRISPR/Cas9 editing and performed functional analysis. Next, we studied the cellular and molecular consequences of the recurrent p.Thr87Ile variant by microscopy, RNA and protein analysis in NIH3T3 cells, primary human fibroblasts and bone biopsy. RESULTS C. elegans heterozygous for the unc-116 Thr90Ile variant displayed abnormal body length and motility phenotypes that were suppressed by additional copies of the wild type allele, consistent with a dominant negative mechanism. Time-lapse imaging of GFP-tagged mitochondria showed defective mitochondria transport in unc-116 Thr90Ile neurons providing strong evidence for disrupted kinesin motor function. Microscopy studies in human cells showed dilated endoplasmic reticulum, multiple intracellular vacuoles, and abnormal distribution of the Golgi complex, supporting an intracellular trafficking defect. RNA sequencing, proteomic analysis, and bone immunohistochemistry demonstrated down regulation of the mTOR signaling pathway that was partially rescued with leucine supplementation in patient cells. CONCLUSION We report dominant negative variants in the KIF5B kinesin motor domain in individuals with osteogenesis imperfecta. This study expands the spectrum of kinesin-related disorders and identifies dysregulated signaling targets for KIF5B in skeletal development.
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Affiliation(s)
- Ronit Marom
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children’s Hospital, Houston, Texas, United States of America
| | - Bo Zhang
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Megan E. Washington
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - I-Wen Song
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lindsay C. Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children’s Hospital, Houston, Texas, United States of America
| | - Vittoria C. Rossi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children’s Hospital, Houston, Texas, United States of America
| | - Ava S. Berrier
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Anika Lindsey
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Jacob Lesinski
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Michael L. Nonet
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Jian Chen
- Department of Genetics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Dustin Baldridge
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Gary A. Silverman
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - V. Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children’s Hospital, Houston, Texas, United States of America
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alyssa A. Tran
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - M. John Hicks
- Texas Children’s Hospital, Houston, Texas, United States of America
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas, United States of America
| | - David R. Murdock
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hongzheng Dai
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - MaryAnn Weis
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington, United States of America
| | - Shalini N. Jhangiani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Donna M. Muzny
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Richard A. Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Richard Caswell
- Exeter Genomics Laboratory, Royal Devon University Healthcare NHS Foundation Trust, Exeter, United Kingdom
| | - Carrie Pottinger
- All Wales Medical Genomics Service, Wrexham Maelor Hospital, Wrexham, UK
| | - Deirdre Cilliers
- Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Karen Stals
- Exeter Genomics Laboratory, Royal Devon University Healthcare NHS Foundation Trust, Exeter, United Kingdom
| | | | - David Eyre
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington, United States of America
| | - Deborah Krakow
- Human Genetics, Obstetrics & Gynecology, Orthopedic Surgery, University of California, Los Angeles, California, United States of America
| | - Tim Schedl
- Department of Genetics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Stephen C. Pak
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Brendan H. Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children’s Hospital, Houston, Texas, United States of America
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2
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Shen S, Si M, Zeng C, Liu EK, Chen Y, Vacher J, Zhao H, Mohan S, Xing W. Leucine Repeat Rich Kinase 1 Controls Osteoclast Activity by Managing Lysosomal Trafficking and Secretion. BIOLOGY 2023; 12:511. [PMID: 37106712 PMCID: PMC10135754 DOI: 10.3390/biology12040511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/21/2023] [Accepted: 03/23/2023] [Indexed: 03/31/2023]
Abstract
We previously demonstrated that mice with targeted deletion of the leucine repeat rich kinase 1 (Lrrk1) gene were osteopetrotic due to the failure of osteoclasts to resorb bone. To determine how LRRK1 regulates osteoclast activity, we examined the intracellular and extracellular acidification with an acidotropic probe, acridine orange, in live osteoclasts on bone slices. We examined lysosome distribution in osteoclasts by localization of LAMP-2, cathepsin K, and v-ATPase by immunofluorescent staining with specific antibodies. We found that both vertical and horizontal cross-sectional images of the wild-type (WT) osteoclasts showed orange-staining of the intracellular acidic vacuoles/lysosomes dispersed to the ruffled border. By contrast, the LRRK1 deficient osteoclasts exhibited fluorescent orange staining in the cytoplasm away from the extracellular lacunae because of an altered distribution of the acidic vacuoles/lysosomes. In addition, WT osteoclasts displayed a peripheral distribution of LAMP-2 positive lysosomes with a typical actin ring. The clustered F-actin constitutes a peripheral sealing zone and a ruffled border which was stretched out into a resorption pit. The LAMP-2 positive lysosomes were also distributed to the sealing zone, and the cell was associated with a resorption pit. By contrast, LRRK1-deficient osteoclasts showed diffused F-actin throughout the cytoplasm. The sealing zone was weak and not associated with a resorption pit. LAMP-2 positive lysosomes were also diffuse in the cytoplasm and were not distributed to the ruffled border. Although the LRRK1-deficient osteoclast expressed normal levels of cathepsin K and v-ATPase, the lysosomal-associated cathepsin K and v-ATPase were not accumulated at the ruffled border in Lrrk1 KO osteoclasts. Our data indicate that LRRK1 controls osteoclast activity by regulating lysosomal distribution, acid secretion, and protease exocytosis.
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Affiliation(s)
- Sandi Shen
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
| | - Mingjue Si
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
| | - Canjun Zeng
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
| | - Elaine K. Liu
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, CA 92357, USA
| | - Yian Chen
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, CA 92357, USA
| | - Jean Vacher
- Institut de Recherches Cliniques de Montreal, Montreal, QC H2W 1R7, Canada
- Département de Médecine, Université de Montréal, Montréal, QC H2W 1R7, Canada
| | - Haibo Zhao
- Southern California Institute for Research and Education, Long Beach, CA 90822, USA
| | - Subburaman Mohan
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
| | - Weirong Xing
- Musculoskeletal Disease Center, Jerry L Pettis VA Medical Center, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
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3
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Vacher J. OSTM1 pleiotropic roles from osteopetrosis to neurodegeneration. Bone 2022; 163:116505. [PMID: 35902071 DOI: 10.1016/j.bone.2022.116505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 11/28/2022]
Abstract
Autosomal recessive osteopetroses (ARO) are rare genetic skeletal disorders of high clinical and molecular heterogeneity with an estimated frequency of 1:250,000 worldwide. The manifestations are diverse and although individually rare, the various forms contribute to the prevalence of a significant number of affected individuals with considerable morbidity and mortality. Among the ARO classification, the most severe form is the autosomal recessive-5 (OPTB5) osteopetrosis (OMIM 259720) that results from homozygous mutation in the OSTM1 gene (607649). OSTM1 mutations account for approximately 5 % of instances of autosomal recessive osteopetrosis and lead to a highly debilitating form of the disease in infancy and death within the first few years of life (Sobacchi et al., 2013) [1].
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Affiliation(s)
- Jean Vacher
- Institut de Recherches Cliniques de Montréal (IRCM), 110 avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada; Département de Médecine, Université de Montréal, Montréal, Québec, Canada.
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4
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Mutabaruka MS, Pata M, Vacher J. A Foxo1-Klf2-S1pr1-Gnai1-Rac1 signaling axis is a critical mediator of Ostm1 regulatory network in T lymphopoiesis. iScience 2022; 25:104160. [PMID: 35434560 PMCID: PMC9010627 DOI: 10.1016/j.isci.2022.104160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 02/23/2022] [Accepted: 03/23/2022] [Indexed: 12/13/2022] Open
Abstract
Ostm1 mutations cause the severe form of osteopetrosis with bone marrow deficiency in humans and mice, yet a role in T cell ontogeny remains to be determined. Herein, we show that thymi of the Ostm1-null mice (gl/gl) from P8-to-P15 become markedly hypocellular with disturbed architecture. Analysis of gl/gl early T cell program determined a major decrease of 3-fold in bone marrow common lymphoid precursors (CLP), 35-fold in early thymic precursors (ETPs) and 100-fold in T cell double positive subpopulations. Ostm1 ablation in T cell double negative (DN) also appears to induce fast-paced differentiation kinetics with a transitory intermediate CD44+CD25int subpopulation. Transgenic targeting Ostm1 expression from the gl/gl DN1 population partially rescued T cell subpopulations from ETP onwards and normalized the accelerated DN differentiation, indicating a cell-autonomous role for Ostm1. Transcriptome of early DN1 population identified an Ostm1 crosstalk with a Foxo1-Klf2-S1pr1-Gnai1-Rac1 signaling axis. Our findings establish that Ostm1 is an essential regulator of T cell ontogeny. Loss of Ostm1 causes severe thymus hypocellularity Ostm1 is a modulator of the T cell differentiation program from the CLPs onwards Targeted CD2-Ostm1 in Ostm1 null mice leads to partial rescue of DN differentiation Ostm1 null DN1 transcriptome identifies a Foxo1-Klf2-S1pr1-Gnai1-Rac1 signaling axis
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Affiliation(s)
- Marie S Mutabaruka
- Institut de Recherches Cliniques de Montréal, 110 West Pins Avenue, Montréal, QC H2W 1R7, Canada.,Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, QC H3A 1A3, Canada
| | - Monica Pata
- Institut de Recherches Cliniques de Montréal, 110 West Pins Avenue, Montréal, QC H2W 1R7, Canada
| | - Jean Vacher
- Institut de Recherches Cliniques de Montréal, 110 West Pins Avenue, Montréal, QC H2W 1R7, Canada.,Département de Médecine, Université de Montréal, Montréal, QC H3T 3J7, Canada.,Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, QC H3A 1A3, Canada
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5
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Rössler U, Hennig AF, Stelzer N, Bose S, Kopp J, Søe K, Cyganek L, Zifarelli G, Ali S, von der Hagen M, Strässler ET, Hahn G, Pusch M, Stauber T, Izsvák Z, Gossen M, Stachelscheid H, Kornak U. Efficient generation of osteoclasts from human induced pluripotent stem cells and functional investigations of lethal CLCN7-related osteopetrosis. J Bone Miner Res 2021; 36:1621-1635. [PMID: 33905594 DOI: 10.1002/jbmr.4322] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 03/26/2021] [Accepted: 04/21/2021] [Indexed: 12/18/2022]
Abstract
Human induced pluripotent stem cells (hiPSCs) hold great potential for modeling human diseases and the development of innovative therapeutic approaches. Here, we report on a novel, simplified differentiation method for forming functional osteoclasts from hiPSCs. The three-step protocol starts with embryoid body formation, followed by hematopoietic specification, and finally osteoclast differentiation. We observed continuous production of monocyte-like cells over a period of up to 9 weeks, generating sufficient material for several osteoclast differentiations. The analysis of stage-specific gene and surface marker expression proved mesodermal priming, the presence of monocyte-like cells, and of terminally differentiated multinucleated osteoclasts, able to form resorption pits and trenches on bone and dentine in vitro. In comparison to peripheral blood mononuclear cell (PBMC)-derived osteoclasts hiPSC-derived osteoclasts were larger and contained a higher number of nuclei. Detailed functional studies on the resorption behavior of hiPSC-osteoclasts indicated a trend towards forming more trenches than pits and an increase in pseudoresorption. We used hiPSCs from an autosomal recessive osteopetrosis (ARO) patient (BIHi002-A, ARO hiPSCs) with compound heterozygous missense mutations p.(G292E) and p.(R403Q) in CLCN7, coding for the Cl- /H+ -exchanger ClC-7, for functional investigations. The patient's leading clinical feature was a brain malformation due to defective neuronal migration. Mutant ClC-7 displayed residual expression and retained lysosomal co-localization with OSTM1, the gene coding for the osteopetrosis-associated transmembrane protein 1, but only ClC-7 harboring the mutation p.(R403Q) gave strongly reduced ion currents. An increased autophagic flux in spite of unchanged lysosomal pH was evident in undifferentiated ARO hiPSCs. ARO hiPSC-derived osteoclasts showed an increased size compared to hiPSCs of healthy donors. They were not able to resorb bone, underlining a loss-of-function effect of the mutations. In summary, we developed a highly reproducible, straightforward hiPSC-osteoclast differentiation protocol. We demonstrated that osteoclasts differentiated from ARO hiPSCs can be used as a disease model for ARO and potentially also other osteoclast-related diseases. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Uta Rössler
- BIH Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute for Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
| | - Anna Floriane Hennig
- BIH Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute for Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Freie Universität Berlin, Berlin, Germany.,Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Nina Stelzer
- BIH Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute for Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Shroddha Bose
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Johannes Kopp
- BIH Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute for Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Freie Universität Berlin, Berlin, Germany.,Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Kent Søe
- Clinical Cell Biology, Department of Pathology, Odense University Hospital, Odense C, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense M, Denmark.,Department of Molecular Medicine, University of Southern Denmark, Odense M, Denmark
| | - Lukas Cyganek
- Stem Cell Unit, Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
| | | | - Salaheddine Ali
- BIH Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute for Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Maja von der Hagen
- Abteilung Neuropädiatrie, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Elisabeth Tamara Strässler
- Department of Cardiology, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany.,German Centre for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany
| | - Gabriele Hahn
- Institut und Poliklinik für Radiologische Diagnostik, Medizinische Fakultät Carl Gustav Carus Technische Universität Dresden, Dresden, Germany
| | | | - Tobias Stauber
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.,Department of Human Medicine, and Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Zsuzsanna Izsvák
- Max-Delbrück-Center for Molecular Medicine (MDC), Helmholtz Association, Berlin, Germany
| | - Manfred Gossen
- Berlin-Brandenburg Center for Regenerative Therapies, Charité Virchow Campus, Berlin, Germany.,Institute of Active Polymers, Helmholtz-Zentrum Hereon, Teltow, Germany
| | - Harald Stachelscheid
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Berlin Institute of Health (BIH), BIH Stem Cell Core Facility, Berlin, Germany
| | - Uwe Kornak
- BIH Center for Regenerative Therapies (BCRT), Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute for Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany.,Max Planck Institute for Molecular Genetics, Berlin, Germany
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6
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Bose S, He H, Stauber T. Neurodegeneration Upon Dysfunction of Endosomal/Lysosomal CLC Chloride Transporters. Front Cell Dev Biol 2021; 9:639231. [PMID: 33708769 PMCID: PMC7940362 DOI: 10.3389/fcell.2021.639231] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/03/2021] [Indexed: 12/15/2022] Open
Abstract
The regulation of luminal ion concentrations is critical for the function of, and transport between intracellular organelles. The importance of the acidic pH in the compartments of the endosomal-lysosomal pathway has been well-known for decades. Besides the V-ATPase, which pumps protons into their lumen, a variety of ion transporters and channels is involved in the regulation of the organelles' complex ion homeostasis. Amongst these are the intracellular members of the CLC family, ClC-3 through ClC-7. They localize to distinct but overlapping compartments of the endosomal-lysosomal pathway, partially with tissue-specific expression. Functioning as 2Cl−/H+ exchangers, they can support the vesicular acidification and accumulate luminal Cl−. Mutations in the encoding genes in patients and mouse models underlie severe phenotypes including kidney stones with CLCN5 and osteopetrosis or hypopigmentation with CLCN7. Dysfunction of those intracellular CLCs that are expressed in neurons lead to neuronal defects. Loss of endosomal ClC-3, which heteromerizes with ClC-4, results in neurodegeneration. Mutations in ClC-4 are associated with epileptic encephalopathy and intellectual disability. Mice lacking the late endosomal ClC-6 develop a lysosomal storage disease with reduced pain sensitivity. Human gene variants have been associated with epilepsy, and a gain-of-function mutation causes early-onset neurodegeneration. Dysfunction of the lysosomal ClC-7 leads to a lysosomal storage disease and neurodegeneration in mice and humans. Reduced luminal chloride, as well as altered calcium regulation, has been associated with lysosomal storage diseases in general. This review discusses the properties of endosomal and lysosomal Cl−/H+ exchange by CLCs and how various alterations of ion transport by CLCs impact organellar ion homeostasis and function in neurodegenerative disorders.
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Affiliation(s)
- Shroddha Bose
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Hailan He
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.,Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Tobias Stauber
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.,Department of Human Medicine and Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
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7
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Pata M, Yousefi Behzadi P, Vacher J. Expression pattern of the V5-Ostm1 protein in bacterial artificial chromosome transgenic mice. Genesis 2021; 59:e23409. [PMID: 33484096 DOI: 10.1002/dvg.23409] [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: 12/07/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 11/08/2022]
Abstract
Mutations in the osteopetrotic transmembrane protein 1 (Ostm1) gene are responsible for the most severe form of autosomal recessive osteopetrosis both in humans and in the gray lethal (gl/gl) mouse. This defect leads to increased bone mass with bone marrow occlusion and hematopoietic defects. To establish the expression profile of the mouse Ostm1 protein in vivo, homologous recombination in bacteria was designed to generate a V5-Ostm1 bacterial artificial chromosome (BAC) that was subsequently integrated in the mouse genome. Tissue expression of the transgene V5-Ostm1 RNA and protein in transgenic mice follow the endogenous expression profile. Immunohistochemistry analysis demonstrated expression in neuronal populations from central and peripheral nervous system and defined a unique cellular expression pattern. Importantly, together with appropriate protein post-translational modification, in vivo rescue of the osteopetrotic bone gl/gl phenotype in BAC V5-Ostm1 gl/gl mice is consistent with the expression of a fully functional and active protein. These mice represent a unique tool to unravel novel Ostm1 functions in individual tissue and neuronal cell populations and the V5-Ostm1 transgene represents an easy visual marker to monitor the expression of Ostm1 in vitro and in vivo.
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Affiliation(s)
- Monica Pata
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Pardis Yousefi Behzadi
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada.,Département de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Jean Vacher
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada.,Département de Médecine, Université de Montréal, Montréal, Québec, Canada.,Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, Quebec, Canada
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8
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Roy M, Roux S. Rab GTPases in Osteoclastic Bone Resorption and Autophagy. Int J Mol Sci 2020; 21:ijms21207655. [PMID: 33081155 PMCID: PMC7589333 DOI: 10.3390/ijms21207655] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/11/2020] [Accepted: 10/13/2020] [Indexed: 12/17/2022] Open
Abstract
Small guanosine triphosphate hydrolases (GTPases) of the Rab family are involved in plasma membrane delivery, fusion events, and lysosomal and autophagic degradation pathways, thereby regulating signaling pathways and cell differentiation and function. Osteoclasts are bone-resorbing cells that maintain bone homeostasis. Polarized vesicular trafficking pathways result in the formation of the ruffled border, the osteoclast’s resorptive organelle, which also assists in transcytosis. Here, we reviewed the different roles of Rab GTPases in the endomembrane machinery of osteoclasts and in bone diseases caused by the dysfunction of these proteins, with a particular focus on autophagy and bone resorption. Understanding the molecular mechanisms underlying osteoclast-related bone disease development is critical for developing and improving therapies.
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Vacher J, Bruccoleri M, Pata M. Ostm1 from Mouse to Human: Insights into Osteoclast Maturation. Int J Mol Sci 2020; 21:ijms21165600. [PMID: 32764302 PMCID: PMC7460669 DOI: 10.3390/ijms21165600] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 07/29/2020] [Accepted: 08/04/2020] [Indexed: 12/14/2022] Open
Abstract
The maintenance of bone mass is a dynamic process that requires a strict balance between bone formation and resorption. Bone formation is controlled by osteoblasts, while osteoclasts are responsible for resorption of the bone matrix. The opposite functions of these cell types have to be tightly regulated not only during normal bone development, but also during adult life, to maintain serum calcium homeostasis and sustain bone integrity to prevent bone fractures. Disruption of the control of bone synthesis or resorption can lead to an over accumulation of bone tissue in osteopetrosis or conversely to a net depletion of the bone mass in osteoporosis. Moreover, high levels of bone resorption with focal bone formation can cause Paget’s disease. Here, we summarize the steps toward isolation and characterization of the osteopetrosis associated trans-membrane protein 1 (Ostm1) gene and protein, essential for proper osteoclast maturation, and responsible when mutated for the most severe form of osteopetrosis in mice and humans.
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Affiliation(s)
- Jean Vacher
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, QC H2W 1R7, Canada; (M.B.); (M.P.)
- Departement de Medecine, Universite de Montreal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, QC H3A 1A3, Canada
- Correspondence:
| | - Michael Bruccoleri
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, QC H2W 1R7, Canada; (M.B.); (M.P.)
- Departement de Medecine, Universite de Montreal, Montreal, QC H2W 1R7, Canada
| | - Monica Pata
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, QC H2W 1R7, Canada; (M.B.); (M.P.)
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10
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Osteopetrosis-Associated Transmembrane Protein 1 Recruits RNA Exosome To Restrict Hepatitis B Virus Replication. J Virol 2020; 94:JVI.01800-19. [PMID: 32188736 DOI: 10.1128/jvi.01800-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/22/2020] [Indexed: 02/07/2023] Open
Abstract
Hepatitis B virus (HBV) chronically infects approximately 350 million people worldwide, and 600,000 deaths are caused by HBV-related hepatic failure, liver cirrhosis, and hepatocellular carcinoma annually. It is important to reveal the mechanism underlying the regulation of HBV replication. This study demonstrated that osteopetrosis-associated transmembrane protein 1 (Ostm1) plays an inhibitory role in HBV replication. Ostm1 represses the levels of HBeAg and HBsAg proteins, HBV 3.5-kb and 2.4/2.1-kb RNAs, and core-associated DNA in HepG2, Huh7, and NTCP-HepG2 cells. Notably, Ostm1 has no direct effect on the activity of HBV promoters or the transcription of HBV RNAs; instead, Ostm1 binds to HBV RNA to facilitate RNA decay. Detailed studies further demonstrated that Ostm1 binds to and recruits the RNA exosome complex to promote the degradation of HBV RNAs, and knockdown of the RNA exosome component exonuclease 3 (Exosc3) leads to the elimination of Ostm1-mediated repression of HBV replication. Mutant analyses revealed that the N-terminal domain, the transmembrane domain, and the C-terminal domain are responsible for the repression of HBV replication, and the C-terminal domain is required for interaction with the RNA exosome complex. Moreover, Ostm1 production is not regulated by interferon-α (IFN-α) or IFN-γ, and the expression of IFN signaling components is not affected by Ostm1, suggesting that Ostm1 anti-HBV activity is independent of the IFN signaling pathway. In conclusion, this study revealed a distinct mechanism underlying the repression of HBV replication, in which Ostm1 binds to HBV RNA and recruits RNA exosomes to degrade viral RNA, thereby restricting HBV replication.IMPORTANCE Hepatitis B virus (HBV) is a human pathogen infecting the liver to cause a variety of diseases ranging from acute hepatitis to advanced liver diseases, fulminate hepatitis, liver cirrhosis, and hepatocellular carcinoma, thereby causing a major health problem worldwide. In this study, we demonstrated that Ostm1 plays an inhibitory role in HBV protein production, RNA expression, and DNA replication. However, Ostm1 has no effect on the activities of the four HBV promoters; instead, it binds to HBV RNA and recruits RNA exosomes to promote HBV RNA degradation. We further demonstrated that the anti-HBV activity of Ostm1 is independent of the interferon signaling pathway. In conclusion, this study reveals a distinct mechanism underlying the repression of HBV replication and suggests that Ostm1 is a potential therapeutic agent for HBV infection.
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11
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Jentsch TJ, Pusch M. CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease. Physiol Rev 2018; 98:1493-1590. [DOI: 10.1152/physrev.00047.2017] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl−channels, whereas ClC-3 through ClC-7 are 2Cl−/H+-exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl−channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.
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Affiliation(s)
- Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; and Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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12
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Pata M, Vacher J. Ostm1 Bifunctional Roles in Osteoclast Maturation: Insights From a Mouse Model Mimicking a Human OSTM1 Mutation. J Bone Miner Res 2018; 33:888-898. [PMID: 29297601 DOI: 10.1002/jbmr.3378] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/21/2017] [Accepted: 12/27/2017] [Indexed: 11/12/2022]
Abstract
Ostm1 mutations are responsible for the most severe form of osteopetrosis in human and mice. To gain insight into Ostm1 cellular functions, we engineered a conditional in-frame deletion of the Ostm1 transmembrane domain and generated the first Ostm1 mouse model with a human mutation. Systemic targeting of Ostm1 loss of transmembrane domain produced osteopetrosis, as in the null Ostm1 gl/gl mouse. Significantly, conditional osteoclast targeting of Ostm1 resulted in similar osteopetrosis, thereby demonstrating that the intrinsic Ostm1 osteoclast deficiency is solely responsible for the mouse phenotype. Our analysis showed oversized osteoclasts with enhanced multinucleation associated with stimulation of intracellular calcium levels, of Nfatc1 nuclear re-localization, and of specific downstream Nfatc1 target genes, providing compelling evidence that Ostm1 is a negative regulator of preosteoclast fusion. Moreover, mature OCs with Ostm1 loss of transmembrane domain show appropriate levels of intracellular acidification but an altered distribution pattern, highlighting misregulation of endolysosome localization and dispersion. Consistently, the hydrolases tartrate-resistant acid phosphatase (TRAP) and cathepsin K (Ctsk) normally produced are sequestered within the osteoclasts and are not extracellularly secreted. These studies defined bifunctional roles for Ostm1 as a major regulator of preosteoclast cytoskeletal rearrangements toward cell multinucleation and of mature osteoclast intracellular lysosomal trafficking and exocytosis mechanism, both of which are essential for bone resorption. Importantly, these Ostm1 molecular and regulatory functions could serve as preclinical targets in this mouse model toward osteoclastogenic pathologies as osteoporosis and inflammation-induced bone loss. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Monica Pata
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Jean Vacher
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada.,Département de Médecine, Université de Montréal, Montréal, Québec, Canada.,Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
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13
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Abstract
PURPOSE OF REVIEW The term osteopetrosis refers to a group of rare skeletal diseases sharing the hallmark of a generalized increase in bone density owing to a defect in bone resorption. Osteopetrosis is clinically and genetically heterogeneous, and a precise molecular classification is relevant for prognosis and treatment. Here, we review recent data on the pathogenesis of this disorder. RECENT FINDINGS Novel mutations in known genes as well as defects in new genes have been recently reported, further expanding the spectrum of molecular defects leading to osteopetrosis. Exploitation of next-generation sequencing tools is ever spreading, facilitating differential diagnosis. Some complex phenotypes in which osteopetrosis is accompanied by additional clinical features have received a molecular classification, also involving new genes. Moreover, novel types of mutations have been recognized, which for their nature or genomic location are at high risk being neglected. Yet, the causative mutation is unknown in some patients, indicating that the genetics of osteopetrosis still deserves intense research efforts.
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Affiliation(s)
- Eleonora Palagano
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy
| | - Ciro Menale
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy
- Milan Unit, CNR-IRGB, Milan, Italy
| | - Cristina Sobacchi
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy.
- Milan Unit, CNR-IRGB, Milan, Italy.
| | - Anna Villa
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy
- Milan Unit, CNR-IRGB, Milan, Italy
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14
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Genome-wide haplotype-based association analysis of major depressive disorder in Generation Scotland and UK Biobank. Transl Psychiatry 2017; 7:1263. [PMID: 29187746 PMCID: PMC5802488 DOI: 10.1038/s41398-017-0010-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 08/16/2017] [Accepted: 08/20/2017] [Indexed: 12/22/2022] Open
Abstract
Genome-wide association studies using genotype data have had limited success in the identification of variants associated with major depressive disorder (MDD). Haplotype data provide an alternative method for detecting associations between variants in weak linkage disequilibrium with genotyped variants and a given trait of interest. A genome-wide haplotype association study for MDD was undertaken utilising a family-based population cohort, Generation Scotland: Scottish Family Health Study (n = 18,773), as a discovery cohort with UK Biobank used as a population-based replication cohort (n = 25,035). Fine mapping of haplotype boundaries was used to account for overlapping haplotypes potentially tagging the same causal variant. Within the discovery cohort, two haplotypes exceeded genome-wide significance (P < 5 × 10-8) for an association with MDD. One of these haplotypes was nominally significant in the replication cohort (P < 0.05) and was located in 6q21, a region which has been previously associated with bipolar disorder, a psychiatric disorder that is phenotypically and genetically correlated with MDD. Several haplotypes with P < 10-7 in the discovery cohort were located within gene coding regions associated with diseases that are comorbid with MDD. Using such haplotypes to highlight regions for sequencing may lead to the identification of the underlying causal variants.
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15
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Santos-Ledo A, Garcia-Macia M, Campbell PD, Gronska M, Marlow FL. Kinesin-1 promotes chondrocyte maintenance during skeletal morphogenesis. PLoS Genet 2017; 13:e1006918. [PMID: 28715414 PMCID: PMC5536392 DOI: 10.1371/journal.pgen.1006918] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/31/2017] [Accepted: 07/11/2017] [Indexed: 01/03/2023] Open
Abstract
During skeletal morphogenesis diverse mechanisms are used to support bone formation. This can be seen in the bones that require a cartilage template for their development. In mammals the cartilage template is removed, but in zebrafish the cartilage template persists and the bone mineralizes around the cartilage scaffold. Remodeling of unmineralized cartilage occurs via planar cell polarity (PCP) mediated cell rearrangements that contribute to lengthening of elements; however, the mechanisms that maintain the chondrocyte template that supports perichondral ossification remain unclear. We report double mutants disrupting two zebrafish kinesin-I genes (hereafter kif5Blof) that we generated using CRISPR/Cas9 mutagenesis. We show that zygotic Kif5Bs have a conserved function in maintaining muscle integrity, and are required for cartilage remodeling and maintenance during craniofacial morphogenesis by a PCP-distinct mechanism. Further, kif5Blof does not activate ER stress response genes, but instead disrupts lysosomal function, matrix secretion, and causes deregulated autophagic markers and eventual chondrocyte apoptosis. Ultrastructural and transplantation analysis reveal neighboring cells engulfing extruded kif5Blof chondrocytes. Initial cartilage specification is intact; however, during remodeling, kif5Blof chondrocytes die and the cartilage matrix devoid of hypertrophic chondrocytes remains and impedes normal ossification. Chimeric and mosaic analyses indicate that Kif5B functions cell-autonomously in secretion, nuclear position, cell elongation and maintenance of hypertrophic chondrocytes. Interestingly, large groups of wild-type cells can support elongation of neighboring mutant cells. Finally, mosaic expression of kif5Ba, but not kif5Aa in cartilage rescues the chondrocyte phenotype, further supporting a specific requirement for Kif5B. Cumulatively, we show essential Kif5B functions in promoting cartilage remodeling and chondrocyte maintenance during zebrafish craniofacial morphogenesis.
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Affiliation(s)
- Adrian Santos-Ledo
- Department of Developmental and Molecular Biology. Albert Einstein College of Medicine, Bronx, New York, United States of America
- Institute of Genetic Medicine. Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Marina Garcia-Macia
- Institute for Cellular and Molecular Biosciences. Newcastle University, Newcastle Upon Tyne, United Kingdom
- Institute of Cellular Medicine. Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Philip D Campbell
- Department of Developmental and Molecular Biology. Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Marta Gronska
- Department of Neuroscience. Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Florence L Marlow
- Department of Developmental and Molecular Biology. Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Neuroscience. Albert Einstein College of Medicine, Bronx, New York, United States of America
- Cell Developmental and Regenerative Biology Department. Icahn School of Medicine at Mount Sinai. New York, New York, United States of America
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16
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Herebian D, Alhaddad B, Seibt A, Schwarzmayr T, Danhauser K, Klee D, Harmsen S, Meitinger T, Strom TM, Schulz A, Mayatepek E, Haack TB, Distelmaier F. Coexisting variants in OSTM1 and MANEAL cause a complex neurodegenerative disorder with NBIA-like brain abnormalities. Eur J Hum Genet 2017; 25:1092-1095. [PMID: 28612835 DOI: 10.1038/ejhg.2017.96] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/04/2017] [Accepted: 05/16/2017] [Indexed: 11/09/2022] Open
Abstract
Coexistence of different hereditary diseases is a known phenomenon in populations with a high consanguinity rate. The resulting clinical phenotypes are extremely challenging for physicians involved in the care of these patients. Here we describe a 6-year-old boy with co-occurrence of a homozygous splice defect in OSTM1, causing infantile malignant osteopetrosis, and a loss-of-function variant in MANEAL, which has not been associated with human disease so far. The child suffered from severe infantile-onset neurodegeneration that could not be stopped by bone marrow transplantation. Magnetic resonance imaging demonstrated global brain atrophy and showed hypointensities of globus pallidus, corpora mamillaria, and cerebral peduncles, which were comparable to findings in neurodegeneration with brain iron accumulation disorders. LC-MS/MS analysis of urine and cerebrospinal fluid samples revealed a distinct metabolic profile with accumulation of mannose tetrasaccharide molecules, suggestive of an oligosaccharide storage disease. Our results demonstrate that exome sequencing is a very effective tool in dissecting complex neurological diseases. Moreover, we suggest that MANEAL is an interesting candidate gene that should be considered in the context of neurological disorders with brain iron accumulation and/or indications of an oligosaccharide storage disease.
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Affiliation(s)
- Diran Herebian
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Duesseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Bader Alhaddad
- Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Annette Seibt
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Duesseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Thomas Schwarzmayr
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Katharina Danhauser
- Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Dirk Klee
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Düsseldorf, Düsseldorf, Germany
| | - Stefani Harmsen
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Duesseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Thomas Meitinger
- Institute of Human Genetics, Technische Universität München, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Tim M Strom
- Institute of Human Genetics, Technische Universität München, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Ansgar Schulz
- Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Ertan Mayatepek
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Duesseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Tobias B Haack
- Institute of Human Genetics, Technische Universität München, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Felix Distelmaier
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Duesseldorf, Heinrich Heine University, Düsseldorf, Germany
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17
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A single transcription factor is sufficient to induce and maintain secretory cell architecture. Genes Dev 2017; 31:154-171. [PMID: 28174210 PMCID: PMC5322730 DOI: 10.1101/gad.285684.116] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 01/13/2017] [Indexed: 01/02/2023]
Abstract
Here, Lo et al. demonstrate that cell architecture can be controlled by a developmentally regulated transcriptional program independent of the program that specifies cell identity. They show that MIST1 (BHLHA15) is a “scaling factor” that universally establishes secretory morphology in cells that perform regulated secretion, and targeted deletion of MIST1 causes dismantling of the secretory apparatus of diverse exocrine cells. We hypothesized that basic helix–loop–helix (bHLH) MIST1 (BHLHA15) is a “scaling factor” that universally establishes secretory morphology in cells that perform regulated secretion. Here, we show that targeted deletion of MIST1 caused dismantling of the secretory apparatus of diverse exocrine cells. Parietal cells (PCs), whose function is to pump acid into the stomach, normally lack MIST1 and do not perform regulated secretion. Forced expression of MIST1 in PCs caused them to expand their apical cytoplasm, rearrange mitochondrial/lysosome trafficking, and generate large secretory granules. Mist1 induced a cohort of genes regulated by MIST1 in multiple organs but did not affect PC function. MIST1 bound CATATG/CAGCTG E boxes in the first intron of genes that regulate autophagosome/lysosomal degradation, mitochondrial trafficking, and amino acid metabolism. Similar alterations in cell architecture and gene expression were also caused by ectopically inducing MIST1 in vivo in hepatocytes. Thus, MIST1 is a scaling factor necessary and sufficient by itself to induce and maintain secretory cell architecture. Our results indicate that, whereas mature cell types in each organ may have unique developmental origins, cells performing similar physiological functions throughout the body share similar transcription factor-mediated architectural “blueprints.”
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