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Gaidt MM, Morrow A, Fairgrieve MR, Karr JP, Yosef N, Vance RE. Self-guarding of MORC3 enables virulence factor-triggered immunity. Nature 2021; 600:138-142. [PMID: 34759314 PMCID: PMC9045311 DOI: 10.1038/s41586-021-04054-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 09/23/2021] [Indexed: 01/08/2023]
Abstract
Pathogens use virulence factors to inhibit the immune system1. The guard hypothesis2,3 postulates that hosts monitor (or 'guard') critical innate immune pathways such that their disruption by virulence factors provokes a secondary immune response1. Here we describe a 'self-guarded' immune pathway in human monocytes, in which guarding and guarded functions are combined in one protein. We find that this pathway is triggered by ICP0, a key virulence factor of herpes simplex virus type 1, resulting in robust induction of anti-viral type I interferon (IFN). Notably, induction of IFN by ICP0 is independent of canonical immune pathways and the IRF3 and IRF7 transcription factors. A CRISPR screen identified the ICP0 target MORC34 as an essential negative regulator of IFN. Loss of MORC3 recapitulates the IRF3- and IRF7-independent IFN response induced by ICP0. Mechanistically, ICP0 degrades MORC3, which leads to de-repression of a MORC3-regulated DNA element (MRE) adjacent to the IFNB1 locus. The MRE is required in cis for IFNB1 induction by the MORC3 pathway, but is not required for canonical IFN-inducing pathways. As well as repressing the MRE to regulate IFNB1, MORC3 is also a direct restriction factor of HSV-15. Our results thus suggest a model in which the primary anti-viral function of MORC3 is self-guarded by its secondary IFN-repressing function-thus, a virus that degrades MORC3 to avoid its primary anti-viral function will unleash the secondary anti-viral IFN response.
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Affiliation(s)
- Moritz M Gaidt
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
| | - Alyssa Morrow
- Electrical Engineering and Computer Science Department, University of California, Berkeley, CA, USA
| | - Marian R Fairgrieve
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Jonathan P Karr
- Division of Genetics, Genomics and Development, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Nir Yosef
- Electrical Engineering and Computer Science Department, University of California, Berkeley, CA, USA
- Center for Computational Biology, University of California, Berkeley, CA, USA
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, Boston, MA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Russell E Vance
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- Cancer Research Laboratory and the Immunotherapeutics and Vaccine Research Initiative, University of California, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
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2
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van Wessel DB, Thompson RJ, Gonzales E, Jankowska I, Shneider BL, Sokal E, Grammatikopoulos T, Kadaristiana A, Jacquemin E, Spraul A, Lipiński P, Czubkowski P, Rock N, Shagrani M, Broering D, Algoufi T, Mazhar N, Nicastro E, Kelly D, Nebbia G, Arnell H, Fischler B, Hulscher JB, Serranti D, Arikan C, Debray D, Lacaille F, Goncalves C, Hierro L, Muñoz Bartolo G, Mozer‐Glassberg Y, Azaz A, Brecelj J, Dezsőfi A, Luigi Calvo P, Krebs‐Schmitt D, Hartleif S, van der Woerd WL, Wang J, Li L, Durmaz Ö, Kerkar N, Hørby Jørgensen M, Fischer R, Jimenez‐Rivera C, Alam S, Cananzi M, Laverdure N, Targa Ferreira C, Ordonez F, Wang H, Sency V, Mo Kim K, Chen H, Carvalho E, Fabre A, Quintero Bernabeu J, Alonso EM, Sokol RJ, Suchy FJ, Loomes KM, McKiernan PJ, Rosenthal P, Turmelle Y, Rao GS, Horslen S, Kamath BM, Rogalidou M, Karnsakul WW, Hansen B, Verkade HJ. Impact of Genotype, Serum Bile Acids, and Surgical Biliary Diversion on Native Liver Survival in FIC1 Deficiency. Hepatology 2021; 74:892-906. [PMID: 33666275 PMCID: PMC8456904 DOI: 10.1002/hep.31787] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 01/17/2021] [Accepted: 01/27/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS Mutations in ATPase phospholipid transporting 8B1 (ATP8B1) can lead to familial intrahepatic cholestasis type 1 (FIC1) deficiency, or progressive familial intrahepatic cholestasis type 1. The rarity of FIC1 deficiency has largely prevented a detailed analysis of its natural history, effects of predicted protein truncating mutations (PPTMs), and possible associations of serum bile acid (sBA) concentrations and surgical biliary diversion (SBD) with long-term outcome. We aimed to provide insights by using the largest genetically defined cohort of patients with FIC1 deficiency to date. APPROACH AND RESULTS This multicenter, combined retrospective and prospective study included 130 patients with compound heterozygous or homozygous predicted pathogenic ATP8B1 variants. Patients were categorized according to the number of PPTMs (i.e., splice site, frameshift due to deletion or insertion, nonsense, duplication), FIC1-A (n = 67; no PPTMs), FIC1-B (n = 29; one PPTM), or FIC1-C (n = 34; two PPTMs). Survival analysis showed an overall native liver survival (NLS) of 44% at age 18 years. NLS was comparable among FIC1-A, FIC1-B, and FIC1-C (% NLS at age 10 years: 67%, 41%, and 59%, respectively; P = 0.12), despite FIC1-C undergoing SBD less often (% SBD at age 10 years: 65%, 57%, and 45%, respectively; P = 0.03). sBAs at presentation were negatively associated with NLS (NLS at age 10 years, sBAs < 194 µmol/L: 49% vs. sBAs ≥ 194 µmol/L: 15%; P = 0.03). SBD decreased sBAs (230 [125-282] to 74 [11-177] μmol/L; P = 0.005). SBD (HR 0.55, 95% CI 0.28-1.03, P = 0.06) and post-SBD sBA concentrations < 65 μmol/L (P = 0.05) tended to be associated with improved NLS. CONCLUSIONS Less than half of patients with FIC1 deficiency reach adulthood with native liver. The number of PPTMs did not associate with the natural history or prognosis of FIC1 deficiency. sBA concentrations at initial presentation and after SBD provide limited prognostic information on long-term NLS.
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Affiliation(s)
- Daan B.E. van Wessel
- Pediatric Gastroenterology and HepatologyUniversity Medical Center GroningenUniversity of GroningenGroningenthe Netherlands
| | | | - Emmanuel Gonzales
- Pediatric Hepatology & Pediatric Liver Transplant DepartmentCentre de Référence de l’Atrésie des Voies Biliaires et des Cholestases GénétiquesFilière de Santé des Maladies Rares du Foie de l’enfant et de l’adulteEuropean Reference Network RARE‐LIVERAssistance Publique‐Hôpitaux de ParisFaculté de Médecine Paris‐SaclayCHU BicêtreParisFrance
- European Reference Network on Hepatological Diseases
| | - Irena Jankowska
- European Reference Network on Hepatological Diseases
- Gastroenterology, Hepatology, Nutritional Disorders and Pediatricsthe Children’s Memorial Health InstituteWarsawPoland
| | - Benjamin L. Shneider
- Division of Pediatric Gastroenterology, Hepatology, and NutritionDepartment of PediatricsBaylor College of MedicineHoustonTXUSA
- Childhood Liver Disease Research Network (ChiLDReN)
| | - Etienne Sokal
- European Reference Network on Hepatological Diseases
- Cliniques St. LucUniversité Catholique de LouvainBrusselsBelgium
| | | | | | - Emmanuel Jacquemin
- Pediatric Hepatology & Pediatric Liver Transplant DepartmentCentre de Référence de l’Atrésie des Voies Biliaires et des Cholestases GénétiquesFilière de Santé des Maladies Rares du Foie de l’enfant et de l’adulteEuropean Reference Network RARE‐LIVERAssistance Publique‐Hôpitaux de ParisFaculté de Médecine Paris‐SaclayCHU BicêtreParisFrance
- INSERMUMR‐S 1193Université Paris‐SaclayOrsayFrance
| | - Anne Spraul
- INSERMUMR‐S 1193Université Paris‐SaclayOrsayFrance
- Biochemistry UnitCentre de Référence de l’Atrésie des Voies Biliaires et des Cholestases GénétiquesFilière de Santé des Maladies Rares du Foie de l’enfant et de l’adulteEuropean Reference Network RARE‐LIVERAssistance Publique‐Hôpitaux de ParisFaculté de Médecine Paris‐SaclayCHU BicêtreParisFrance
| | - Patryk Lipiński
- European Reference Network on Hepatological Diseases
- Gastroenterology, Hepatology, Nutritional Disorders and Pediatricsthe Children’s Memorial Health InstituteWarsawPoland
| | - Piotr Czubkowski
- European Reference Network on Hepatological Diseases
- Gastroenterology, Hepatology, Nutritional Disorders and Pediatricsthe Children’s Memorial Health InstituteWarsawPoland
| | - Nathalie Rock
- Cliniques St. LucUniversité Catholique de LouvainBrusselsBelgium
| | - Mohammad Shagrani
- Department of Liver & SB Transplant & Hepatobiliary‐Pancreatic SurgeryKing Faisal Specialist Hospital & Research CenterRiyadhSaudi Arabia
- College of MedicineAlfaisal UniversityRiyadhSaudi Arabia
| | - Dieter Broering
- Department of Liver & SB Transplant & Hepatobiliary‐Pancreatic SurgeryKing Faisal Specialist Hospital & Research CenterRiyadhSaudi Arabia
| | - Talal Algoufi
- Department of Liver & SB Transplant & Hepatobiliary‐Pancreatic SurgeryKing Faisal Specialist Hospital & Research CenterRiyadhSaudi Arabia
| | - Nejat Mazhar
- Department of Liver & SB Transplant & Hepatobiliary‐Pancreatic SurgeryKing Faisal Specialist Hospital & Research CenterRiyadhSaudi Arabia
| | - Emanuele Nicastro
- Pediatric Hepatology, Gastroenterology and TransplantationOspedale Papa Giovanni XXIIIBergamoItaly
| | - Deirdre Kelly
- European Reference Network on Hepatological Diseases
- Liver UnitBirmingham Women’s and Children’s HospitalUniversity of BirminghamBirminghamUnited Kingdom
| | - Gabriella Nebbia
- Servizio Di Epatologia e Nutrizione PediatricaFondazione Irccs Ca’ Granda Ospedale Maggiore PoliclinicoMilanoItaly
| | - Henrik Arnell
- European Reference Network on Hepatological Diseases
- Pediatric Digestive DiseasesAstrid Lindgren Children’s HospitalCLINTECKarolinska InstitutetKarolinska University HospitalStockholmSweden
| | - Björn Fischler
- European Reference Network on Hepatological Diseases
- Pediatric Digestive DiseasesAstrid Lindgren Children’s HospitalCLINTECKarolinska InstitutetKarolinska University HospitalStockholmSweden
| | - Jan B.F. Hulscher
- European Reference Network on Hepatological Diseases
- Pediatric SurgeryUniversity Medical Center GroningenGroningenthe Netherlands
| | - Daniele Serranti
- Pediatric and Liver UnitMeyer Children’s University Hospital of FlorenceFlorenceItaly
| | - Cigdem Arikan
- Pediatric GI and Hepatology Liver Transplantation CenterKuttam System in Liver MedicineKoc University School of MedicineIstanbulTurkey
| | - Dominique Debray
- Pediatric Hepatology unit, Reference Center for Biliary Atresia and Genetic Cholestatic DiseasesFilière de Santé des Maladies Rares du Foie de l’enfant et de l’adulteEuropean Reference Network RARE‐LIVERAPHP‐Neckler Enfants Malades University HospitalFaculté de Médecine Paris‐CentreParisFrance
| | - Florence Lacaille
- Pediatric Hepatology unit, Reference Center for Biliary Atresia and Genetic Cholestatic DiseasesFilière de Santé des Maladies Rares du Foie de l’enfant et de l’adulteEuropean Reference Network RARE‐LIVERAPHP‐Neckler Enfants Malades University HospitalFaculté de Médecine Paris‐CentreParisFrance
| | - Cristina Goncalves
- European Reference Network on Hepatological Diseases
- Coimbra University Hospital CenterCoimbraPortugal
| | - Loreto Hierro
- European Reference Network on Hepatological Diseases
- Pediatric Liver ServiceLa Paz University HospitalMadridSpain
| | - Gema Muñoz Bartolo
- European Reference Network on Hepatological Diseases
- Pediatric Liver ServiceLa Paz University HospitalMadridSpain
| | - Yael Mozer‐Glassberg
- Institute of Gastroenterology, Nutrition and Liver DiseasesSchneider Children’s Medical Center of IsraelPetach TikvahIsrael
| | - Amer Azaz
- Sheikh Khalifa Medical CityAbu DhabiUnited Arab Emirates
| | - Jernej Brecelj
- Department of Gastroenterology, Hepatology and NutritionUniversity Children’s Hospital LjubljanaLjubljanaSlovenia
- Department of PediatricsFaculty of MedicineUniversity of LjubljanaLjubljanaSlovenia
| | - Antal Dezsőfi
- First Department of PediatricsSemmelweis UniversityBudapestHungary
| | - Pier Luigi Calvo
- Pediatic Gastroenterology UnitRegina Margherita Children’s HospitalAzienda Ospedaliera Città Della Salute e Della Scienza University HospitalTorinoItaly
| | | | - Steffen Hartleif
- European Reference Network on Hepatological Diseases
- University Children’s Hospital TϋbingenTϋbingenGermany
| | - Wendy L. van der Woerd
- Pediatric Gastroenterology, Hepatology and NutritionWilhelmina Children’s HospitalUniversity Medical Center UtrechtUtrechtthe Netherlands
| | - Jian‐She Wang
- Children’s Hospital of Fudan UniversityShanghaiChina
| | - Li‐ting Li
- Children’s Hospital of Fudan UniversityShanghaiChina
| | - Özlem Durmaz
- Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
| | - Nanda Kerkar
- Pediatric Gastroenterology, Hepatology and NutritionUniversity of Rochester Medical CenterRochesterNYUSA
| | - Marianne Hørby Jørgensen
- European Reference Network on Hepatological Diseases
- Pediatric and Adolescent DepartmentDepartment of Pediatrics and Adolescent MedicineRigshospitalet Copenhagen University HospitalCopenhagenDenmark
| | - Ryan Fischer
- Section of Hepatology and Transplant MedicineChildren’s Mercy HospitalKansas CityMOUSA
| | - Carolina Jimenez‐Rivera
- Department of PediatricsChildren’s Hospital of Eastern OntarioUniversity of OttawaOttawaCanada
| | - Seema Alam
- Pediatric HepatologyInstitute of Liver and Biliary SciencesNew DelhiIndia
| | - Mara Cananzi
- European Reference Network on Hepatological Diseases
- Pediatric Gastroenterology and HepatologyUniversity Hospital of PadovaPadovaItaly
| | - Noémie Laverdure
- European Reference Network on Hepatological Diseases
- Service de Gastroentérologie, Hépatologie et Nutrition PédiatriquesHospices Civils de LyonHôpital Femme Mère EnfantLyonFrance
| | | | - Felipe Ordonez
- Fundación Cardioinfantil Instituto de CardiologiaPediatric Gastroenterology and HepatologyBogotáColombia
| | - Heng Wang
- DDC Clinic Center for Special Needs ChildrenMiddlefieldOHUSA
| | - Valerie Sency
- DDC Clinic Center for Special Needs ChildrenMiddlefieldOHUSA
| | - Kyung Mo Kim
- Department of PediatricsAsan Medical Center Children’s HospitalSeoulSouth Korea
| | - Huey‐Ling Chen
- Division of Pediatric Gastroenterology, Hepatology and NutritionNational Taiwan University Children’s HospitalTaipeiTaiwan
| | - Elisa Carvalho
- Pediatric Gastroenterology and HepatologyBrasília Children’s HospitalBrasiliaBrazil
| | - Alexandre Fabre
- INSERMMMGAix Marseille UniversityMarseilleFrance
- Serveice de Pédiatrie MultidisciplinaireTimone EnfantMarseilleFrance
| | - Jesus Quintero Bernabeu
- European Reference Network on Hepatological Diseases
- Pediatric Hepatology and Liver Transplant UnitBarcelonaSpain
| | - Estella M. Alonso
- Childhood Liver Disease Research Network (ChiLDReN)
- Division of Pediatric Gastroenterology, Hepatology and NutritionAnn & Robert H. Lurie Children’s HospitalChicagoILUSA
| | - Ronald J. Sokol
- Childhood Liver Disease Research Network (ChiLDReN)
- Section of Pediatric Gastroenterology, Hepatology and NutritionDepartment of PediatricsChildren’s Hospital ColoradoUniversity of Colorado School of MedicineAuroraCOUSA
| | - Frederick J. Suchy
- Childhood Liver Disease Research Network (ChiLDReN)
- Icahn School of Medicine at Mount SinaiMount Sinai Kravis Children’s HospitalNew YorkNYUSA
| | - Kathleen M. Loomes
- Childhood Liver Disease Research Network (ChiLDReN)
- Division of Gastroenterology, Hepatology and NutritionChildren’s Hospital of PhiladelphiaPhiladelphiaPAUSA
| | - Patrick J. McKiernan
- Childhood Liver Disease Research Network (ChiLDReN)
- Department of Pediatric Gastroenterology and HepatologyUniversity of Pittsburgh Medical Center Children’s Hospital of PittsburghPittsburghPAUSA
| | - Philip Rosenthal
- Childhood Liver Disease Research Network (ChiLDReN)
- Department of Pediatrics and SurgeryUCSF Benioff Children’s HospitalUniversity of California San Francisco School of MedicineSan FranciscoCAUSA
| | - Yumirle Turmelle
- Childhood Liver Disease Research Network (ChiLDReN)
- Section of HepatologyDepartment of PediatricsSt. Louis Children’s HospitalWashington University School of MedicineSt. LouisMOUSA
| | - Girish S. Rao
- Childhood Liver Disease Research Network (ChiLDReN)
- Riley Hospital for ChildrenIndiana University School of MedicineIndianapolisINUSA
| | - Simon Horslen
- Childhood Liver Disease Research Network (ChiLDReN)
- Department of PediatricsSeattle Children’s HospitalUniversity of WashingtonSeattleWAUSA
| | - Binita M. Kamath
- Childhood Liver Disease Research Network (ChiLDReN)
- The Hospital for Sick ChildrenUniversity of TorontoTorontoCanada
| | - Maria Rogalidou
- Division of Pediatric Gastroenterology & HepatologyFirst Pediatrics DepartmentUniversity of AthensAgia Sofia Children’s HospitalAthensGreece
| | - Wikrom W. Karnsakul
- Division of Pediatric Gastroenterology, Nutrition, and HepatologyDepartment of PediatricsJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Bettina Hansen
- Toronto Center for Liver DiseaseUniversity Health NetworkTorontoCanada
- IHPMEUniversity of TorontoTorontoCanada
| | - Henkjan J. Verkade
- Pediatric Gastroenterology and HepatologyUniversity Medical Center GroningenUniversity of GroningenGroningenthe Netherlands
- European Reference Network on Hepatological Diseases
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3
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Mizutani A, Sabu Y, Naoi S, Ito S, Nakano S, Minowa K, Mizuochi T, Ito K, Abukawa D, Kaji S, Sasaki M, Muroya K, Azuma Y, Watanabe S, Oya Y, Inomata Y, Fukuda A, Kasahara M, Inui A, Takikawa H, Kusuhara H, Bessho K, Suzuki M, Togawa T, Hayashi H. Assessment of Adenosine Triphosphatase Phospholipid Transporting 8B1 (ATP8B1) Function in Patients With Cholestasis With ATP8B1 Deficiency by Using Peripheral Blood Monocyte-Derived Macrophages. Hepatol Commun 2021; 5:52-62. [PMID: 33437900 PMCID: PMC7789840 DOI: 10.1002/hep4.1605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/11/2020] [Accepted: 08/20/2020] [Indexed: 11/29/2022] Open
Abstract
Adenosine triphosphatase phospholipid transporting 8B1 (ATP8B1) deficiency, an ultrarare autosomal recessive liver disease, includes severe and mild clinical forms, referred to as progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis type 1 (BRIC1), respectively. There is currently no practical method for determining PFIC1 or BRIC1 at an early disease course phase. Herein, we assessed the feasibility of developing a diagnostic method for PFIC1 and BRIC1. A nationwide Japanese survey conducted since 2015 identified 25 patients with cholestasis with ATP8B1 mutations, 15 of whom agreed to participate in the study. Patients were divided for analysis into PFIC1 (n = 10) or BRIC1 (n = 5) based on their disease course. An in vitro mutagenesis assay to evaluate pathogenicity of ATP8B1 mutations suggested that residual ATP8B1 function in the patients could be used to identify clinical course. To assess their ATP8B1 function more simply, human peripheral blood monocyte-derived macrophages (HMDMs) were prepared from each patient and elicited into a subset of alternatively activated macrophages (M2c) by interleukin-10 (IL-10). This was based on our previous finding that ATP8B1 contributes to polarization of HMDMs into M2c. Flow cytometric analysis showed that expression of M2c-related surface markers cluster of differentiation (CD)14 and CD163 were 2.3-fold and 2.1-fold lower (95% confidence interval, 2.0-2.5 for CD14 and 1.7-2.4 for CD163), respectively, in patients with IL-10-treated HMDMs from PFIC1 compared with BRIC1. Conclusion: CD14 and CD163 expression levels in IL-10-treated HMDMs may facilitate diagnosis of PFIC1 or BRIC1 in patients with ATP8B1 deficiency.
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Affiliation(s)
- Ayumu Mizutani
- Laboratory of Molecular PharmacokineticsGraduate School of Pharmaceutical SciencesUniversity of TokyoTokyoJapan
| | - Yusuke Sabu
- Laboratory of Molecular PharmacokineticsGraduate School of Pharmaceutical SciencesUniversity of TokyoTokyoJapan
| | - Sotaro Naoi
- Laboratory of Molecular PharmacokineticsGraduate School of Pharmaceutical SciencesUniversity of TokyoTokyoJapan
| | - Shogo Ito
- Department of Pediatrics and NeonatologyNagoya City University Graduate School of Medical SciencesNagoyaJapan
| | - Satoshi Nakano
- Department of PediatricsJuntendo University School of MedicineTokyoJapan
| | - Kei Minowa
- Department of PediatricsJuntendo University School of MedicineTokyoJapan
| | - Tatsuki Mizuochi
- Department of Pediatrics and Child HealthKurume University School of MedicineFukuokaJapan
| | - Koichi Ito
- Department of Pediatrics and NeonatologyNagoya City University Graduate School of Medical SciencesNagoyaJapan
| | - Daiki Abukawa
- Department of Gastroenterology and HepatologyMiyagi Children's HospitalMiyagiJapan
| | - Shunsaku Kaji
- Department of PediatricsTsuyama‐Chuo HospitalOkayamaJapan
| | - Mika Sasaki
- Department of PediatricsSchool of MedicineIwate Medical UniversityIwateJapan
| | - Koji Muroya
- Department of Endocrinology and MetabolismKanagawa Children's Medical CenterKanagawaJapan
| | - Yoshihiro Azuma
- Department of PediatricsYamaguchi University Graduate School of MedicineYamaguchiJapan
| | - Satoshi Watanabe
- Department of PediatricsNagasaki University HospitalNagasakiJapan
| | - Yuki Oya
- Department of Transplantation/Pediatric SurgeryKumamoto UniversityKumamotoJapan
- Kumamoto UniversityKumamotoJapan
| | - Yukihiro Inomata
- Department of Transplantation/Pediatric SurgeryKumamoto UniversityKumamotoJapan
- Kumamoto UniversityKumamotoJapan
| | - Akinari Fukuda
- Organ Transplantation CenterNational Center for Child Health and DevelopmentTokyoJapan
| | - Mureo Kasahara
- Organ Transplantation CenterNational Center for Child Health and DevelopmentTokyoJapan
| | - Ayano Inui
- Department of Pediatric Hepatology and GastroenterologyEastern Yokohama HospitalKanagawaJapan
| | - Hajime Takikawa
- Department of MedicineTeikyo University School of MedicineTokyoJapan
| | - Hiroyuki Kusuhara
- Laboratory of Molecular PharmacokineticsGraduate School of Pharmaceutical SciencesUniversity of TokyoTokyoJapan
| | - Kazuhiko Bessho
- Department of PediatricsOsaka University Graduate School of MedicineOsakaJapan
| | - Mitsuyoshi Suzuki
- Department of PediatricsJuntendo University School of MedicineTokyoJapan
| | - Takao Togawa
- Department of Pediatrics and NeonatologyNagoya City University Graduate School of Medical SciencesNagoyaJapan
| | - Hisamitsu Hayashi
- Laboratory of Molecular PharmacokineticsGraduate School of Pharmaceutical SciencesUniversity of TokyoTokyoJapan
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4
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Morillo-Huesca M, Murillo-Pineda M, Barrientos-Moreno M, Gómez-Marín E, Clemente-Ruiz M, Prado F. Actin and Nuclear Envelope Components Influence Ectopic Recombination in the Absence of Swr1. Genetics 2019; 213:819-834. [PMID: 31533921 PMCID: PMC6827384 DOI: 10.1534/genetics.119.302580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/17/2019] [Indexed: 12/11/2022] Open
Abstract
The accuracy of most DNA processes depends on chromatin integrity and dynamics. Our analyses in the yeast Saccharomyces cerevisiae show that an absence of Swr1 (the catalytic and scaffold subunit of the chromatin-remodeling complex SWR) leads to the formation of long-duration Rad52, but not RPA, foci and to an increase in intramolecular recombination. These phenotypes are further increased by MMS, zeocin, and ionizing radiation, but not by double-strand breaks, HU, or transcription/replication collisions, suggesting that they are associated with specific DNA lesions. Importantly, these phenotypes can be specifically suppressed by mutations in: (1) chromatin-anchorage internal nuclear membrane components (mps3∆75-150 and src1∆); (2) actin and actin regulators (act1-157, act1-159, crn1∆, and cdc42-6); or (3) the SWR subunit Swc5 and the SWR substrate Htz1 However, they are not suppressed by global disruption of actin filaments or by the absence of Csm4 (a component of the external nuclear membrane that forms a bridging complex with Mps3, thus connecting the actin cytoskeleton with chromatin). Moreover, swr1∆-induced Rad52 foci and intramolecular recombination are not associated with tethering recombinogenic DNA lesions to the nuclear periphery. In conclusion, the absence of Swr1 impairs efficient recombinational repair of specific DNA lesions by mechanisms that are influenced by SWR subunits, including actin, and nuclear envelope components. We suggest that these recombinational phenotypes might be associated with a pathological effect on homologous recombination of actin-containing complexes.
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Affiliation(s)
- Macarena Morillo-Huesca
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), Consejo Superior de Investigaciones Científicas-University of Seville-University Pablo de Olavide, Spain
| | - Marina Murillo-Pineda
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), Consejo Superior de Investigaciones Científicas-University of Seville-University Pablo de Olavide, Spain
| | - Marta Barrientos-Moreno
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), Consejo Superior de Investigaciones Científicas-University of Seville-University Pablo de Olavide, Spain
| | - Elena Gómez-Marín
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), Consejo Superior de Investigaciones Científicas-University of Seville-University Pablo de Olavide, Spain
| | - Marta Clemente-Ruiz
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), Consejo Superior de Investigaciones Científicas-University of Seville-University Pablo de Olavide, Spain
| | - Félix Prado
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), Consejo Superior de Investigaciones Científicas-University of Seville-University Pablo de Olavide, Spain
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5
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Wang J, Li W, Zhou F, Feng R, Wang F, Zhang S, Li J, Li Q, Wang Y, Xie J, Wen T. ATP11B deficiency leads to impairment of hippocampal synaptic plasticity. J Mol Cell Biol 2019; 11:688-702. [PMID: 31152587 PMCID: PMC7261485 DOI: 10.1093/jmcb/mjz042] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/28/2019] [Accepted: 03/15/2019] [Indexed: 12/13/2022] Open
Abstract
Synaptic plasticity is known to regulate and support signal transduction between neurons, while synaptic dysfunction contributes to multiple neurological and other brain disorders; however, the specific mechanism underlying this process remains unclear. In the present study, abnormal neural and dendritic morphology was observed in the hippocampus following knockout of Atp11b both in vitro and in vivo. Moreover, ATP11B modified synaptic ultrastructure and promoted spine remodeling via the asymmetrical distribution of phosphatidylserine and enhancement of glutamate release, glutamate receptor expression, and intracellular Ca2+ concentration. Furthermore, experimental results also indicate that ATP11B regulated synaptic plasticity in hippocampal neurons through the MAPK14 signaling pathway. In conclusion, our data shed light on the possible mechanisms underlying the regulation of synaptic plasticity and lay the foundation for the exploration of proteins involved in signal transduction during this process.
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Affiliation(s)
- Jiao Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Weihao Li
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Fangfang Zhou
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Ruili Feng
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Fushuai Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Shibo Zhang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Jie Li
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Qian Li
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Yajiang Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Jiang Xie
- School of Computer Engineering and Science, Shanghai University, Shanghai, China
| | - Tieqiao Wen
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
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6
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Dirr ER, Ekhator OR, Blackwood R, Holden JG, Masliah E, Schultheis PJ, Fleming SM. Exacerbation of sensorimotor dysfunction in mice deficient in Atp13a2 and overexpressing human wildtype alpha-synuclein. Behav Brain Res 2018; 343:41-49. [PMID: 29407413 PMCID: PMC5829010 DOI: 10.1016/j.bbr.2018.01.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 01/17/2018] [Accepted: 01/22/2018] [Indexed: 12/26/2022]
Abstract
Loss of function mutations in the gene ATP13A2 are associated with Kufor-Rakeb Syndrome and Neuronal Ceroid Lipofuscinosis, the former designated as an inherited form of Parkinson's disease (PD). The function of ATP13A2 is unclear but in vitro studies indicate it is a lysosomal protein and may interact with the presynaptic protein alpha-synuclein (aSyn) and certain heavy metals. Accumulation of aSyn is a major component of lewy bodies, the pathological hallmark of PD. Atp13a2-deficient (13a2) mice develop age-dependent sensorimotor deficits, and accumulation of insoluble aSyn in the brain. To better understand the interaction between ATP13A2 and aSyn, double mutant mice with loss of Atp13a2 function combined with overexpression of human wildtype aSyn were generated. Female and male wildtype (WT), 13a2, aSyn, and 13a2-aSyn mice were tested on a battery of sensorimotor tests including adhesive removal, challenging beam traversal, spontaneous activity, gait, locomotor activity, and nest-building at 2, 4, and 6 months of age. Double mutant mice showed an earlier onset and accelerated alterations in sensorimotor function that were age, sex and test-dependent. Female 13a2-aSyn mice showed early and progressive dysfunction on the beam and in locomotor activity. In males, 13a2-aSyn mice showed more severe impairments in spontaneous activity and adhesive removal. Sex differences were also observed in aSyn and 13a2-aSyn mice on the beam, cylinder, and adhesive removal tests. In other tasks, double mutant mice displayed deficits similar to aSyn mice. These results indicate loss of Atp13a2 function exacerbates the sensorimotor phenotype in aSyn mice in an age and sex-dependent manner.
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Affiliation(s)
- Emily R Dirr
- Department of Neurology, School of Medicine, University of Cincinnati, USA
| | - Osunde R Ekhator
- Department of Neurology, School of Medicine, University of Cincinnati, USA
| | - Rachel Blackwood
- Department of Neurology, School of Medicine, University of Cincinnati, USA
| | - John G Holden
- Department of Neurology, School of Medicine, University of Cincinnati, USA
| | | | | | - Sheila M Fleming
- Department of Pharmaceutical Sciences and Center for Neurodegenerative Disease and Aging, Northeast Ohio Medical University, USA.
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7
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Luthra A, Swinehart W, Bayooz S, Phan P, Stec B, Iwata-Reuyl D, Swairjo MA. Structure and mechanism of a bacterial t6A biosynthesis system. Nucleic Acids Res 2018; 46:1395-1411. [PMID: 29309633 PMCID: PMC5814804 DOI: 10.1093/nar/gkx1300] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 12/13/2017] [Accepted: 12/19/2017] [Indexed: 11/12/2022] Open
Abstract
The universal N(6)-threonylcarbamoyladenosine (t6A) modification at position 37 of ANN-decoding tRNAs is central to translational fidelity. In bacteria, t6A biosynthesis is catalyzed by the proteins TsaB, TsaC/TsaC2, TsaD and TsaE. Despite intense research, the molecular mechanisms underlying t6A biosynthesis are poorly understood. Here, we report biochemical and biophysical studies of the t6A biosynthesis system from Thermotoga maritima. Small angle X-ray scattering analysis reveals a symmetric 2:2 stoichiometric complex of TsaB and TsaD (TsaB2D2), as well as 2:2:2 complex (TsaB2D2E2), in which TsaB acts as a dimerization module, similar to the role of Pcc1 in the archaeal system. The TsaB2D2 complex is the minimal platform for the binding of one tRNA molecule, which can then accommodate a single TsaE subunit. Kinetic data demonstrate that TsaB2D2 alone, and a TsaB2D2E1 complex with TsaE mutants deficient in adenosine triphosphatase (ATPase) activity, can catalyze only a single cycle of t6A synthesis, while gel shift experiments provide evidence that the role of TsaE-catalyzed ATP hydrolysis occurs after the release of product tRNA. Based on these results, we propose a model for t6A biosynthesis in bacteria.
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Affiliation(s)
- Amit Luthra
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - William Swinehart
- Department of Chemistry, PO Box 751 Portland State University, Portland, OR 97207, USA
| | - Susan Bayooz
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Phuc Phan
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Boguslaw Stec
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Dirk Iwata-Reuyl
- Department of Chemistry, PO Box 751 Portland State University, Portland, OR 97207, USA
| | - Manal A Swairjo
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
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8
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Sigruener A, Wolfrum C, Boettcher A, Kopf T, Liebisch G, Orsó E, Schmitz G. Lipidomic and metabolic changes in the P4-type ATPase ATP10D deficient C57BL/6J wild type mice upon rescue of ATP10D function. PLoS One 2017; 12:e0178368. [PMID: 28542499 PMCID: PMC5444826 DOI: 10.1371/journal.pone.0178368] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 05/11/2017] [Indexed: 01/01/2023] Open
Abstract
Background Sequence variants near the human gene for P4-type ATPase, class V, type 10D (ATP10D) were shown to significantly associate with circulating hexosylceramide d18:1/16:0 and d18:1/24:1 levels, obesity, insulin resistance, plasma high density lipoprotein (HDL), coronary stenotic index and intracranial atherosclerotic index. In mice Atp10d is associated with HDL modulation and C57BL/6 mice expressing a truncated, non-functional form of ATP10D easily develop obesity and insulin resistance on high-fat diet. Results We analyzed metabolic differences of ATP10D deficient C57BL/6J wild type and ATP10D transgenic C57BL/6J BAC129 mice. ATP10D transgenic mice gain 25% less weight on high-fat diet concomitant with a reduced increase in fat cell mass but independent of adipocyte size change. ATP10D transgenic mice also had 26% lower triacylglycerol levels with approximately 76% bound to very low density lipoprotein while in ATP10D deficient wild type mice 57% are bound to low density lipoprotein. Furthermore increased oxygen consumption and CO2 production, 38% lower glucose and 69% lower insulin levels and better insulin sensitivity were observed in ATP10D transgenic mice. Besides decreased hexosylceramide species levels were detected. Part of these effects may be due to reduced hepatic stearoyl-CoA desaturase 1 (SCD1) expression in ATP10D transgenic mice, which was reflected by altered fatty acid and lipid species patterns. There was a significant decrease in the hepatic 18:1 to 18:0 free fatty acid ratio in transgenic mice. The ratio of 16:1 to 16:0 was not significantly different. Interestingly both ratios were significantly reduced in plasma total fatty acids. Summary In summary we found that ATP10D reduces high-fat diet induced obesity and improves insulin sensitivity. ATP10D transgenic mice showed altered hepatic expression of lipid-metabolism associated genes, including Scd1, along with changes in hepatic and plasma lipid species and plasma lipoprotein pattern.
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Affiliation(s)
- Alexander Sigruener
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Medical Center, Regensburg, Germany
- * E-mail:
| | - Christian Wolfrum
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
| | - Alfred Boettcher
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Medical Center, Regensburg, Germany
| | - Thomas Kopf
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Medical Center, Regensburg, Germany
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Medical Center, Regensburg, Germany
| | - Evelyn Orsó
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Medical Center, Regensburg, Germany
| | - Gerd Schmitz
- Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Medical Center, Regensburg, Germany
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Navarathna DHMLP, Pathirana RU, Lionakis MS, Nickerson KW, Roberts DD. Candida albicans ISW2 Regulates Chlamydospore Suspensor Cell Formation and Virulence In Vivo in a Mouse Model of Disseminated Candidiasis. PLoS One 2016; 11:e0164449. [PMID: 27727302 PMCID: PMC5058487 DOI: 10.1371/journal.pone.0164449] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 09/26/2016] [Indexed: 01/05/2023] Open
Abstract
Formation of chlamydospores by Candida albicans was an established medical diagnostic test to confirm candidiasis before the molecular era. However, the functional role and pathological relevance of this in vitro morphological transition to pathogenesis in vivo remain unclear. We compared the physical properties of in vitro-induced chlamydospores with those of large C. albicans cells purified by density gradient centrifugation from Candida-infected mouse kidneys. The morphological and physical properties of these cells in kidneys of mice infected intravenously with wild type C. albicans confirmed that chlamydospores can form in infected kidneys. A previously reported chlamydospore-null Δisw2/Δisw2 mutant was used to investigate its role in virulence and chlamydospore induction. Virulence of the Δisw2/Δisw2 mutant strain was reduced 3.4-fold compared to wild type C. albicans or the ISW2 reconstituted strain. Altered host inflammatory reactions to the null mutant further indicate that ISW2 is a virulence factor in C. albicans. ISW2 deletion abolished chlamydospore formation within infected mouse kidneys, whereas the reconstituted strain restored chlamydospore formation in kidneys. Under chlamydospore inducing conditions in vitro, deletion of ISW2 significantly delayed chlamydospore formation, and those late induced chlamydospores lacked associated suspensor cells while attaching laterally to hyphae via novel spore-hypha septa. Our findings establish the induction of chlamydospores by C. albicans during mouse kidney colonization. Our results indicate that ISW2 is not strictly required for chlamydospores formation but is necessary for suspensor cell formation. The importance of ISW2 in chlamydospore morphogenesis and virulence may lead to additional insights into morphological differentiation and pathogenesis of C. albicans in the host microenvironment.
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Affiliation(s)
- Dhammika H. M. L. P. Navarathna
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ruvini U. Pathirana
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Michail S. Lionakis
- Fungal Pathogenesis Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kenneth W. Nickerson
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - David D. Roberts
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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Ezzatizadeh V, Sandi C, Sandi M, Anjomani-Virmouni S, Al-Mahdawi S, Pook MA. MutLα heterodimers modify the molecular phenotype of Friedreich ataxia. PLoS One 2014; 9:e100523. [PMID: 24971578 PMCID: PMC4074104 DOI: 10.1371/journal.pone.0100523] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/28/2014] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Friedreich ataxia (FRDA), the most common autosomal recessive ataxia disorder, is caused by a dynamic GAA repeat expansion mutation within intron 1 of FXN gene, resulting in down-regulation of frataxin expression. Studies of cell and mouse models have revealed a role for the mismatch repair (MMR) MutS-heterodimer complexes and the PMS2 component of the MutLα complex in the dynamics of intergenerational and somatic GAA repeat expansions: MSH2, MSH3 and MSH6 promote GAA repeat expansions, while PMS2 inhibits GAA repeat expansions. METHODOLOGY/PRINCIPAL FINDINGS To determine the potential role of the other component of the MutLα complex, MLH1, in GAA repeat instability in FRDA, we have analyzed intergenerational and somatic GAA repeat expansions from FXN transgenic mice that have been crossed with Mlh1 deficient mice. We find that loss of Mlh1 activity reduces both intergenerational and somatic GAA repeat expansions. However, we also find that loss of either Mlh1 or Pms2 reduces FXN transcription, suggesting different mechanisms of action for Mlh1 and Pms2 on GAA repeat expansion dynamics and regulation of FXN transcription. CONCLUSIONS/SIGNIFICANCE Both MutLα components, PMS2 and MLH1, have now been shown to modify the molecular phenotype of FRDA. We propose that upregulation of MLH1 or PMS2 could be potential FRDA therapeutic approaches to increase FXN transcription.
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Affiliation(s)
- Vahid Ezzatizadeh
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Chiranjeevi Sandi
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Madhavi Sandi
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Sara Anjomani-Virmouni
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Sahar Al-Mahdawi
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
| | - Mark A. Pook
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University London, Uxbridge, United Kingdom
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11
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Chandhok G, Schmitt N, Sauer V, Aggarwal A, Bhatt M, Schmidt HHJ. The effect of zinc and D-penicillamine in a stable human hepatoma ATP7B knockout cell line. PLoS One 2014; 9:e98809. [PMID: 24892424 PMCID: PMC4044041 DOI: 10.1371/journal.pone.0098809] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/07/2014] [Indexed: 12/27/2022] Open
Abstract
Mutations in the copper (Cu) transporter gene ATP7B, the primary cause of Wilson disease (WD), result in high liver Cu and death of hepatocytes. Cu chelators and zinc salts are the two most important drugs used in the treatment of WD patients; however, the molecular mechanisms of the drugs with regard to ATP7B expression have not been determined. A targeted knockout of ATP7B (KO) was established in the most widely used human hepatoma cell line, HepG2 for molecular studies of the pathogenesis and treatment of the disease. KO cells showed similar growth, Cu uptake, release, and gene expression as compared to parental cells. However, in the presence of Cu, morphological changes, oxidative stress, apoptosis, and loss of viability were observed. Induction of metallothionein (MT1X) after Cu exposure was significantly reduced in KO cells. Following zinc treatment, MT1X expression was strongly induced and a high percentage of KO cells could be rescued from Cu induced toxicity. D-penicillamine treatment had a minor effect on the viability of KO cells whereas the parental cell line showed a pronounced improvement. Combined treatment displayed a highly synergistic effect in KO cells. The data suggest that zinc has a previously unrecognized effect on the viability of hepatocytes that lack ATP7B due to a high induction of MT1X expression that compensates low gene expression after Cu exposure. A combination therapy that simultaneously targets at MT1X induction and Cu chelation improves the overall survival of hepatocytes for most efficient therapy of patients having WD.
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Affiliation(s)
- Gursimran Chandhok
- Clinic for Transplantation Medicine, Münster University Hospital, Münster, Germany
- Wilson Disease Clinic, Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Mumbai, India
| | - Nadine Schmitt
- Clinic for Transplantation Medicine, Münster University Hospital, Münster, Germany
| | - Vanessa Sauer
- Clinic for Transplantation Medicine, Münster University Hospital, Münster, Germany
| | - Annu Aggarwal
- Wilson Disease Clinic, Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Mumbai, India
| | - Mohit Bhatt
- Wilson Disease Clinic, Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Mumbai, India
| | - Hartmut H. J. Schmidt
- Clinic for Transplantation Medicine, Münster University Hospital, Münster, Germany
- * E-mail:
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12
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Abstract
To achieve permanent correction of Wilson's disease by a cell therapy approach, replacement of diseased hepatocytes with healthy hepatocytes is desirable. There is a physiological requirement for hepatic ATP7B-dependent copper (Cu) transport in bile, which is deficient in Wilson's disease, producing progressive Cu accumulation in the liver or brain with organ damage. The ability to repopulate the liver with healthy hepatocytes raises the possibility of cell therapy in Wilson's disease. Therapeutic principles included reconstitution of bile canalicular network as well as proliferation in transplanted hepatocytes, despite toxic amounts of Cu in the liver. Nonetheless, cell therapy studies in animal models elicited major differences in the mechanisms driving liver repopulation with transplanted hepatocytes in Wilson's disease versus nondiseased settings. Recently, noninvasive imaging was developed to demonstrate Cu removal from the liver, including after cell therapy in Wilson's disease. Such developments will help advance cell/gene therapy approaches, particularly by offering roadmaps for clinical trials in people with Wilson's disease.
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Affiliation(s)
- Sanjeev Gupta
- Marion Bessin Liver Research Center, Cancer Research Center, Diabetes Center, Departments of Medicine and Pathology, Ruth L. and David S. Gottesman Institute for Stem Cell and Regenerative Medicine Research, and Institute for Clinical and Translational Research, Albert Einstein College of Medicine, Bronx, New York
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13
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McDowell SC, López-Marqués RL, Poulsen LR, Palmgren MG, Harper JF. Loss of the Arabidopsis thaliana P₄-ATPase ALA3 reduces adaptability to temperature stresses and impairs vegetative, pollen, and ovule development. PLoS One 2013; 8:e62577. [PMID: 23667493 PMCID: PMC3646830 DOI: 10.1371/journal.pone.0062577] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 03/20/2013] [Indexed: 12/28/2022] Open
Abstract
Members of the P4 subfamily of P-type ATPases are thought to help create asymmetry in lipid bilayers by flipping specific lipids between the leaflets of a membrane. This asymmetry is believed to be central to the formation of vesicles in the secretory and endocytic pathways. In Arabidopsis thaliana, a P4-ATPase associated with the trans-Golgi network (ALA3) was previously reported to be important for vegetative growth and reproductive success. Here we show that multiple phenotypes for ala3 knockouts are sensitive to growth conditions. For example, ala3 rosette size was observed to be dependent upon both temperature and soil, and varied between 40% and 80% that of wild-type under different conditions. We also demonstrate that ala3 mutants have reduced fecundity resulting from a combination of decreased ovule production and pollen tube growth defects. In-vitro pollen tube growth assays showed that ala3 pollen germinated ∼2 h slower than wild-type and had approximately 2-fold reductions in both maximal growth rate and overall length. In genetic crosses under conditions of hot days and cold nights, pollen fitness was reduced by at least 90-fold; from ∼18% transmission efficiency (unstressed) to less than 0.2% (stressed). Together, these results support a model in which ALA3 functions to modify endomembranes in multiple cell types, enabling structural changes, or signaling functions that are critical in plants for normal development and adaptation to varied growth environments.
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Affiliation(s)
- Stephen C. McDowell
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
| | - Rosa L. López-Marqués
- Department of Plant Biology and Biotechnology, Centre for Membrane Pumps in Cells and Disease (PUMPKIN), University of Copenhagen, Danish National Research Foundation, Frederiksberg, Denmark
| | - Lisbeth R. Poulsen
- Department of Plant Biology and Biotechnology, Centre for Membrane Pumps in Cells and Disease (PUMPKIN), University of Copenhagen, Danish National Research Foundation, Frederiksberg, Denmark
| | - Michael G. Palmgren
- Department of Plant Biology and Biotechnology, Centre for Membrane Pumps in Cells and Disease (PUMPKIN), University of Copenhagen, Danish National Research Foundation, Frederiksberg, Denmark
| | - Jeffrey F. Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada, United States of America
- * E-mail:
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14
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Bartolome F, Wu HC, Burchell VS, Preza E, Wray S, Mahoney CJ, Fox NC, Calvo A, Canosa A, Moglia C, Mandrioli J, Chiò A, Orrell RW, Houlden H, Hardy J, Abramov AY, Plun-Favreau H. Pathogenic VCP mutations induce mitochondrial uncoupling and reduced ATP levels. Neuron 2013; 78:57-64. [PMID: 23498975 PMCID: PMC3843114 DOI: 10.1016/j.neuron.2013.02.028] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2013] [Indexed: 11/23/2022]
Abstract
Valosin-containing protein (VCP) is a highly expressed member of the type II AAA+ ATPase family. VCP mutations are the cause of inclusion body myopathy, Paget's disease of the bone, and frontotemporal dementia (IBMPFD) and they account for 1%-2% of familial amyotrophic lateral sclerosis (ALS). Using fibroblasts from patients carrying three independent pathogenic mutations in the VCP gene, we show that VCP deficiency causes profound mitochondrial uncoupling leading to decreased mitochondrial membrane potential and increased mitochondrial oxygen consumption. This mitochondrial uncoupling results in a significant reduction of cellular ATP production. Decreased ATP levels in VCP-deficient cells lower their energy capacity, making them more vulnerable to high energy-demanding processes such as ischemia. Our findings propose a mechanism by which pathogenic VCP mutations lead to cell death.
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MESH Headings
- Adenosine Triphosphatases/deficiency
- Adenosine Triphosphatases/genetics
- Adenosine Triphosphate/metabolism
- Adult
- Aged
- Analysis of Variance
- Animals
- Animals, Newborn
- Case-Control Studies
- Cell Cycle Proteins/deficiency
- Cell Cycle Proteins/genetics
- Cells, Cultured
- Cerebral Cortex/cytology
- Family Health
- Female
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Frontotemporal Dementia/genetics
- Frontotemporal Dementia/metabolism
- Frontotemporal Dementia/pathology
- Humans
- Lipid Peroxidation/genetics
- Luminescent Proteins/genetics
- Magnesium/metabolism
- Male
- Membrane Potential, Mitochondrial/genetics
- Mice
- Mice, Inbred C57BL
- Middle Aged
- Mitochondria/genetics
- Mitochondria/metabolism
- Mitochondria/pathology
- Muscular Dystrophies, Limb-Girdle/genetics
- Muscular Dystrophies, Limb-Girdle/metabolism
- Muscular Dystrophies, Limb-Girdle/pathology
- Mutation/genetics
- Myositis, Inclusion Body/genetics
- Myositis, Inclusion Body/metabolism
- Myositis, Inclusion Body/pathology
- NAD/metabolism
- Neuroblastoma/pathology
- Neurons/ultrastructure
- Osteitis Deformans/genetics
- Osteitis Deformans/metabolism
- Osteitis Deformans/pathology
- Oxygen Consumption/genetics
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Transfection
- Valosin Containing Protein
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Affiliation(s)
- Fernando Bartolome
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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15
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Peng F, Lutsenko S, Sun X, Muzik O. Imaging copper metabolism imbalance in Atp7b (-/-) knockout mouse model of Wilson's disease with PET-CT and orally administered 64CuCl2. Mol Imaging Biol 2013; 14:600-7. [PMID: 22170165 DOI: 10.1007/s11307-011-0532-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES This study aims to determine the feasibility and utility of functional imaging of copper metabolism imbalance in Atp7b (-/-) knockout mouse model of Wilson's disease (WD) with positron emission tomography-computed tomography (PET-CT) using orally administered copper-64 chloride ((64)CuCl(2)) as a tracer. PROCEDURES Atp7b (-/-) KO mice (N = 5) were subjected to PET scanning using a hybrid PET-CT scanner, after oral administration of (64)CuCl(2) as a tracer. Time-dependent PET quantitative analysis was performed to assess gastrointestinal absorption and biodistribution of (64)Cu radioactivity in the Atp7b (-/-) KO mice, using C57BL wild-type (WT) mice (N = 5) as a normal control. Estimates of human radiation dosimetry were calculated based on biodistribution of (64)Cu radioactivity in live animals. RESULTS PET-CT analysis demonstrated higher (64)Cu radioactivity in the liver of Atp7b (-/-) knockout mice compared with that in the control C57BL WT mice (p < 0.001), following oral administration of (64)CuCl(2) as a tracer. In addition, (64)Cu radioactivity in the lungs of the Atp7b (-/-) knockout mice was slightly higher than those in the control C57BL WT mice (p = 0.01). Despite initially higher renal clearance of (64)Cu, there was no significant difference of (64)Cu radioactivity in the kidneys of the Atp7b (-/-) KO mice and the control C57BL WT mice at 24 h post-oral administration of (64)CuCl(2) (p = 0.16). There was no significant difference in low (64)Cu radioactivity in the blood, brain, heart, and muscles between the Atp7b (-/-) knockout mice and control C57BL WT mice (p > 0.05). Based on the biodistribution of (64)Cu radioactivity in C57BL WT mice, radiation dosimetry estimates of (64)Cu in normal human subjects were obtained. An effective dose (ED) of 42.4 μSv/MBq (weighted dose over 22 organs) was calculated and the lower large intestines were identified as the critical organ for radiation exposure (120 μGy/MBq for males and 135 μGy/MBq for females). Radiation dosimetry estimates for patients with WD, derived from the biodistribution of (64)Cu in Atp7b (-/-) KO mice, showed a slightly lower ED of 37.5 μSv/MBq, with the lower large intestines as the critical organ for radiation exposure (83 μSv/MBq for male and 95 μSv/MBq for female). CONCLUSIONS PET-CT quantitative analysis demonstrated an increased level of (64)Cu radioactivity in the liver of Atp7b (-/-) KO mice compared with that in the control C57BL WT mice, following oral administration of (64)CuCl(2) as a tracer. The results of this study suggest the feasibility and utility of PET-CT using orally administered (64)CuCl(2) as a tracer ((64)CuCl(2)-PET/CT) for functional imaging of copper metabolism imbalance in WD.
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Affiliation(s)
- Fangyu Peng
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Hines Blvd, Dallas, TX 75390-8542, USA.
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16
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Abstract
PURPOSE This study aims to determine feasibility and utility of copper-64(II) chloride (⁶⁴CuCl₂) as a tracer for positron emission tomography (PET) of copper metabolism imbalance in human Wilson's disease (WD). PROCEDURES Atp7b⁻/⁻ mice, a mouse model of human WD, were injected with ⁶⁴CuCl₂ intravenously and subjected to PET scanning using a hybrid PET-CT (computerized tomography) scanner, with the wild-type C57BL mice as a normal control. Quantitative PET analysis was performed to determine biodistribution of ⁶⁴Cu radioactivity and radiation dosimetry estimates of ⁶⁴Cu were calculated for PET of copper metabolism in humans. RESULTS Dynamic PET analysis revealed increased accumulation and markedly reduced clearance of ⁶⁴Cu from the liver of the Atp7b⁻/⁻ mice, compared to hepatic uptake and clearance of ⁶⁴Cu in the wild-type C57BL mice. Kinetics of copper clearance and retention was also altered for kidneys, heart, and lungs in the Atp7b/⁻ mice. Based on biodistribution of ⁶⁴Cu in wild-type C57BL mice, radiation dosimetry estimates of ⁶⁴Cu in normal human subjects were obtained, showing an effective dose (ED) of 32.2 μ (micro)Sv/MBq (weighted dose over 22 organs) and the small intestine as the critical organ for radiation dose (61 μGy/MBq for males and 69 μGy/MBq for females). Radiation dosimetry estimates for the patients with WD, based on biodistribution of ⁶⁴Cu in the Atp7b⁻/⁻ mice, showed a similar ED of 32.8 μ (micro)Sv/MBq (p = 0.53), with the liver as the critical organ for radiation dose (120 μSv/MBq for male and 161 μSv/MBq for female). CONCLUSIONS Quantitative PET analysis demonstrates abnormal copper metabolism in the mouse model of WD with improved time-resolution. Human radiation dosimetry estimates obtained in this preclinical study encourage direct radiation dosimetry of ⁶⁴CuCl₂ in human subjects. The results suggest feasibility of utilizing ⁶⁴CuCl₂ as a tracer for noninvasive assessment of copper metabolism in WD with PET.
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Affiliation(s)
- Fangyu Peng
- Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8542, USA.
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Gray LW, Peng F, Molloy SA, Pendyala VS, Muchenditsi A, Muzik O, Lee J, Kaplan JH, Lutsenko S. Urinary copper elevation in a mouse model of Wilson's disease is a regulated process to specifically decrease the hepatic copper load. PLoS One 2012; 7:e38327. [PMID: 22802922 PMCID: PMC3390108 DOI: 10.1371/journal.pone.0038327] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 05/03/2012] [Indexed: 12/19/2022] Open
Abstract
Body copper homeostasis is regulated by the liver, which removes excess copper
via bile. In Wilson's disease (WD), this function is disrupted due to
inactivation of the copper transporter ATP7B resulting in hepatic copper
overload. High urinary copper is a diagnostic feature of WD linked to liver
malfunction; the mechanism behind urinary copper elevation is not fully
understood. Using Positron Emission Tomography-Computed Tomography (PET-CT)
imaging of live Atp7b−/− mice at
different stages of disease, a longitudinal metal analysis, and characterization
of copper-binding molecules, we show that urinary copper elevation is a specific
regulatory process mediated by distinct molecules. PET-CT and atomic absorption
spectroscopy directly demonstrate an age-dependent decrease in the capacity of
Atp7b−/− livers to accumulate
copper, concomitant with an increase in urinary copper. This reciprocal
relationship is specific for copper, indicating that cell necrosis is not the
primary cause for the initial phase of metal elevation in the urine. Instead,
the urinary copper increase is associated with the down-regulation of the
copper-transporter Ctr1 in the liver and appearance of a 2 kDa Small Copper
Carrier, SCC, in the urine. SCC is also elevated in the urine of the
liver-specific Ctr1−/− knockouts, which
have normal ATP7B function, suggesting that SCC is a normal metabolite carrying
copper in the serum. In agreement with this hypothesis, partially purified
SCC-Cu competes with free copper for uptake by Ctr1. Thus, hepatic
down-regulation of Ctr1 allows switching to an SCC-mediated removal of copper
via kidney when liver function is impaired. These results demonstrate that the
body regulates copper export through more than one mechanism; better
understanding of urinary copper excretion may contribute to an improved
diagnosis and monitoring of WD.
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Affiliation(s)
- Lawrence W. Gray
- Department of Physiology, Johns Hopkins
University, School of Medicine, Baltimore, Maryland, United States of
America
| | - Fangyu Peng
- Department of Radiology, University of Texas
Southwestern Medical Center, Dallas, Texas, United States of America
| | - Shannon A. Molloy
- Department of Biochemistry and Molecular
Genetics, University of Illinois at Chicago, Chicago, Illinois, United States of
America
| | - Venkata S. Pendyala
- Department of Physiology, Johns Hopkins
University, School of Medicine, Baltimore, Maryland, United States of
America
| | - Abigael Muchenditsi
- Department of Physiology, Johns Hopkins
University, School of Medicine, Baltimore, Maryland, United States of
America
| | - Otto Muzik
- Carman and Ann Adams Department of Pediatrics
and Department of Radiology, Wayne State University, School of Medicine,
Detroit, Michigan, United States of America
| | - Jaekwon Lee
- Redox Biology Center, Department of
Biochemistry, University of Nebraska, Lincoln, Nebraska, United States of
America
| | - Jack H. Kaplan
- Department of Biochemistry and Molecular
Genetics, University of Illinois at Chicago, Chicago, Illinois, United States of
America
| | - Svetlana Lutsenko
- Department of Physiology, Johns Hopkins
University, School of Medicine, Baltimore, Maryland, United States of
America
- * E-mail:
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Groen A, Romero MR, Kunne C, Hoosdally SJ, Dixon PH, Wooding C, Williamson C, Seppen J, Van den Oever K, Mok KS, Paulusma CC, Linton KJ, Oude Elferink RPJ. Complementary functions of the flippase ATP8B1 and the floppase ABCB4 in maintaining canalicular membrane integrity. Gastroenterology 2011; 141:1927-37.e1-4. [PMID: 21820390 DOI: 10.1053/j.gastro.2011.07.042] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 07/12/2011] [Accepted: 07/27/2011] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Progressive familial intrahepatic cholestasis can be caused by mutations in ABCB4 or ATP8B1; each encodes a protein that translocates phospholipids, but in opposite directions. ABCB4 flops phosphatidylcholine from the inner to the outer leaflet, where it is extracted by bile salts. ATP8B1, in complex with the accessory protein CDC50A, flips phosphatidylserine in the reverse direction. Abcb4(-/-) mice lack biliary secretion of phosphatidylcholine, whereas Atp8b1-deficient mice have increased excretion of phosphatidylserine into bile. Each system is thought to have a role protecting the canalicular membrane from bile salts. METHODS To investigate the relationship between the mechanisms of ABCB4 and ATP8B1, we expressed the transporters separately and together in cultured cells and studied viability and phospholipid transport. We also created mice with disruptions in ABCB4 and ATP8B1 (double knockouts) and studied bile formation and hepatic damage in mice fed bile salts. RESULTS Overexpression of ABCB4 was toxic to HEK293T cells; the toxicity was counteracted by coexpression of the ATP8B1-CDC50A complex. In Atp8b1-deficient mice, bile salts induced extraction of phosphatidylserine and ectoenzymes from the canalicular membrane; this process was not observed in the double-knockout mice. CONCLUSIONS ATP8B1 is required for hepatocyte function, particularly in the presence of ABCB4. This is most likely because the phosphatidylserine flippase complex of ATP8B1-CDC50A counteracts the destabilization of the membrane that occurs when ABCB4 flops phosphatidylcholine. Lipid asymmetry is therefore important for the integrity of the canalicular membrane; ABCB4 and ATP8B1 cooperate to protect hepatocytes from bile salts.
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Affiliation(s)
- Annemiek Groen
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands
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Iwai A, Takegami T, Shiozaki T, Miyazaki T. Hepatitis C virus NS3 protein can activate the Notch-signaling pathway through binding to a transcription factor, SRCAP. PLoS One 2011; 6:e20718. [PMID: 21673954 PMCID: PMC3108961 DOI: 10.1371/journal.pone.0020718] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 05/09/2011] [Indexed: 11/18/2022] Open
Abstract
Persistent infections of hepatitis C virus (HCV) are known to be a major risk factor for causing hepatocellular carcinomas. Nonstructural protein 3 (NS3) of HCV has serine protease and RNA helicase domains, and is essential for the viral replication. Further, NS3 is also considered to be involved in the development of HCV-induced hepatocellular carcinomas. In this report, we focus on the function of NS3 protein, and propose a novel possible molecular mechanism which is thought to be related to the tumorigenesis caused by the persistent infection of HCV. We identified SRCAP (Snf2-related CBP activator protein) as a NS3 binding protein using yeast two-hybrid screening, and a co-immunoprecipitation assay demonstrated that NS3 can bind to SRCAP in mammalian cells. The results of a reporter gene assay using Hes-1 promoter which is known to be a target gene activated by Notch, indicate that NS3 and SRCAP cooperatively activate the Hes-1 promoter in Hep3B cells. In addition, we show in this report that also p400, which is known as a protein closely resembling SRCAP, would be targeted by NS3. NS3 exhibited binding activity also to the 1449–1808 region of p400 by a co-immunoprecipitation assay, and further the activation of the Notch-mediated transcription of Hes-1 promoter by NS3 decreased significantly by the combined silencing of SRCAP and p400 mRNA using short hairpin RNA. These results suggest that the HCV NS3 protein is involved in the activation of the Notch-signaling pathway through the targeting to both SRCAP and p400.
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Affiliation(s)
- Atsushi Iwai
- Department of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Hokkaido, Japan
| | - Tsutomu Takegami
- Medical Research Institute, Kanazawa Medical University, Uchinada, Ishikawa, Japan
- * E-mail:
| | - Takuya Shiozaki
- Department of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Hokkaido, Japan
| | - Tadaaki Miyazaki
- Department of Bioresources, Hokkaido University Research Center for Zoonosis Control, Sapporo, Hokkaido, Japan
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Zischka H, Lichtmannegger J, Schmitt S, Jägemann N, Schulz S, Wartini D, Jennen L, Rust C, Larochette N, Galluzzi L, Chajes V, Bandow N, Gilles VS, DiSpirito AA, Esposito I, Goettlicher M, Summer KH, Kroemer G. Liver mitochondrial membrane crosslinking and destruction in a rat model of Wilson disease. J Clin Invest 2011; 121:1508-18. [PMID: 21364284 PMCID: PMC3068979 DOI: 10.1172/jci45401] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 01/05/2011] [Indexed: 11/17/2022] Open
Abstract
Wilson disease (WD) is a rare hereditary condition that is caused by a genetic defect in the copper-transporting ATPase ATP7B that results in hepatic copper accumulation and lethal liver failure. The present study focuses on the structural mitochondrial alterations that precede clinical symptoms in the livers of rats lacking Atp7b, an animal model for WD. Liver mitochondria from these Atp7b–/– rats contained enlarged cristae and widened intermembrane spaces, which coincided with a massive mitochondrial accumulation of copper. These changes, however, preceded detectable deficits in oxidative phosphorylation and biochemical signs of oxidative damage, suggesting that the ultrastructural modifications were not the result of oxidative stress imposed by copper- dependent Fenton chemistry. In a cell-free system containing a reducing dithiol agent, isolated mitochondria exposed to copper underwent modifications that were closely related to those observed in vivo. In this cell-free system, copper induced thiol modifications of three abundant mitochondrial membrane proteins, and this correlated with reversible intramitochondrial membrane crosslinking, which was also observed in liver mitochondria from Atp7b–/– rats. In vivo, copper-chelating agents reversed mitochondrial accumulation of copper, as well as signs of intra-mitochondrial membrane crosslinking, thereby preserving the functional and structural integrity of mitochondria. Together, these findings suggest that the mitochondrion constitutes a pivotal target of copper in WD.
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Affiliation(s)
- Hans Zischka
- Institute of Toxicology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany.
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21
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Zhang Q, Yin NL, Zhang XM, Wang H, Liu X, Cui YL, Yin YB, Xu WC. [Effect of ClpE depletion on the bacterial protein expression profiles of Streptococcus pneumoniae]. Nan Fang Yi Ke Da Xue Xue Bao 2009; 29:1533-1537. [PMID: 19726284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVE To investigate the effect of ClpE on the protein expression profiles of Streptococcus pneumoniae. METHODS clpE-deficient Streptococcus pneumoniae strain was constructed by long flanking homology-polymerase chain reaction (LFH-PCR) and identified by PCR and sequencing. The total bacterial proteins were analyzed by two-dimensional gel electrophoresis and imaging analysis, and the differentially expressed protein spots were excised by dot-gel digestion with trypsin. Peptide mass fingerprinting (PMF) was obtained by analysis of the fragment length by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The PMF was analyzed using software to identify the proteins. RESULTS The number of matched protein spots of the two gels was 61%. By sequence database searching, 4 out of the 17 differential protein spots were identified, namely hypoxanthine-guanine, pyrrolidone-carboxylate peptidase1, formate-tetrahydrofolate ligase, and bifunctional protein pyrR. CONCLUSION clpE gene-deficient Streptococcus pneumoniae expresses fewer kinds of proteins at also lower levels than the wild-type bacteria, suggesting that ClpE allows the bacteria to adapt to different host environments by inducing the expression of special proteins.
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Affiliation(s)
- Qun Zhang
- Key Laboratory of Laboratory Medical Diagnostics of Ministry of Education, Chongqing Medical University, Chongqing 400016, China.
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22
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Nagasaka H, Yorifuji T, Hirano K, Ota A, Toyama-Nakagawa Y, Takatani T, Tsukahara H, Kobayashi K, Takayanagi M, Inomata Y, Uemoto S, Miida T. Effects of bezafibrate on dyslipidemia with cholestasis in children with familial intrahepatic cholestasis-1 deficiency manifesting progressive familial intrahepatic cholestasis. Metabolism 2009; 58:48-54. [PMID: 19059530 DOI: 10.1016/j.metabol.2008.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 08/12/2008] [Indexed: 01/18/2023]
Abstract
No appropriate pharmaceutical therapy has been established for dyslipidemia with cholestasis in progressive familial intrahepatic cholestasis (PFIC)-1. We evaluated the efficacy of bezafibrate in PFIC-1. We monitored the clinical presentation and lipoprotein metabolism of 3 patients, aged 3, 4, and 8 years, with FIC1 deficiency, manifesting PFIC-1, over 12 months of bezafibrate therapy. Pruritus was substantially alleviated in the 3 patients after initiation of bezafibrate. Cholestasis was alleviated in 2 of them. Serum high-density lipoprotein cholesterol and low-density lipoprotein cholesterol increased 1.6- to 2.0-fold and 1.1- to 1.2-fold, respectively; but the values remained low and normal, respectively. Serum lipoprotein X, which was at normal levels before treatment, was elevated to levels above the upper limit of the reference range. High serum triglyceride levels decreased by 15% to 30%, to normal levels, after treatment initiation. The activities of lipoprotein lipase and hepatic triglyceride lipase were increased, but those of high-density lipoprotein regulators remained unchanged. Liver expression of multidrug resistance protein-3, which regulates lipoprotein X synthesis, was enhanced by bezafibrate therapy. Bezafibrate treatment favorably affected pruritus, dyslipidemia, and cholestasis in PFIC-1.
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Affiliation(s)
- Hironori Nagasaka
- Division of Metabolism, Chiba Children's Hospital, Chiba 266-0007, Japan
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Corona DFV, Siriaco G, Armstrong JA, Snarskaya N, McClymont SA, Scott MP, Tamkun JW. ISWI regulates higher-order chromatin structure and histone H1 assembly in vivo. PLoS Biol 2007; 5:e232. [PMID: 17760505 PMCID: PMC1951781 DOI: 10.1371/journal.pbio.0050232] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Accepted: 06/29/2007] [Indexed: 12/17/2022] Open
Abstract
Imitation SWI (ISWI) and other ATP-dependent chromatin-remodeling factors play key roles in transcription and other processes by altering the structure and positioning of nucleosomes. Recent studies have also implicated ISWI in the regulation of higher-order chromatin structure, but its role in this process remains poorly understood. To clarify the role of ISWI in vivo, we examined defects in chromosome structure and gene expression resulting from the loss of Iswi function in Drosophila. Consistent with a broad role in transcriptional regulation, the expression of a large number of genes is altered in Iswi mutant larvae. The expression of a dominant-negative form of ISWI leads to dramatic alterations in higher-order chromatin structure, including the apparent decondensation of both mitotic and polytene chromosomes. The loss of ISWI function does not cause obvious defects in nucleosome assembly, but results in a significant reduction in the level of histone H1 associated with chromatin in vivo. These findings suggest that ISWI plays a global role in chromatin compaction in vivo by promoting the association of the linker histone H1 with chromatin. Chromatin-remodeling factors such as ISWI play a role in transcription and other nuclear processes by altering the structure and positioning of nucleosomes (the protein–DNA complexes that organize chromatin). Recent studies have suggested that chromatin-remodeling factors can also influence higher-order chromatin structure, but how they do this is not well understood. Using Drosophila melanogaster as a model organism, we investigated the role of ISWI in gene expression and the regulation of chromosome structure in higher eukaryotes. Loss of ISWI alters the expression of a large number of genes. The loss of ISWI function also causes dramatic alterations in higher-order chromatin structure—including the decondensation of mitotic and polytene chromosomes—accompanied by a striking reduction in the amount of the linker histone H1 associated with chromatin. Based on these findings, we propose that ISWI plays a global role in chromosome compaction by promoting the association of a linker histone with chromatin. ISWI is a chromatin-remodeling factor that recruits linker histone H1 into chromatin, thus altering the structure and positioning of nucleosomes and the degree of chromatin compaction.
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Affiliation(s)
- Davide F. V Corona
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Giorgia Siriaco
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Jennifer A Armstrong
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Natalia Snarskaya
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Bioengineering, Stanford University School of Medicine, Stanford, California, United States of America
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America
| | - Stephanie A McClymont
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Matthew P Scott
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Bioengineering, Stanford University School of Medicine, Stanford, California, United States of America
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, United States of America
| | - John W Tamkun
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, California, United States of America
- * To whom correspondence should be addressed. E-mail:
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Abstract
A conserved network of eye field transcription factors (EFTFs) underlies the development of the eye in vertebrates and invertebrates. To direct eye development, Pax6, a key gene in this network, interacts with genes encoding other EFTFs such as Rx1 and Six3 (refs 4-6). However, the mechanisms that control expression of the EFTFs remain unclear. Here we show that purine-mediated signalling triggers both EFTF expression and eye development in Xenopus laevis. Overexpression of ectonucleoside triphosphate diphosphohydrolase 2 (E-NTPDase2), an ectoenzyme that converts ATP to ADP, caused ectopic eye-like structures, with occasional complete duplication of the eye, and increased expression of Pax6, Rx1 and Six3. In contrast, downregulation of endogenous E-NTPDase2 decreased Rx1 and Pax6 expression. E-NTPDase2 therefore acts upstream of these EFTFs. To test whether ADP (the product of E-NTPDase2) might act to trigger eye development through P2Y1 receptors, selective in Xenopus for ADP, we simultaneously knocked down expression of the genes encoding E-NTPDase2 and the P2Y1 receptor. This could prevent the expression of Rx1 and Pax6 and eye formation completely. We next measured ATP release in the presumptive eye field, demonstrating a transient release of ATP at a time that could plausibly trigger (once converted to ADP) expression of the EFTFs. This surprising role for transient purine-mediated signalling in eye development may be widely conserved, because alterations to the locus of E-NTPDase2 on human chromosome 9 cause severe head and eye defects, including microphthalmia. Our results suggest a new mechanism for the initiation of eye development.
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Affiliation(s)
- Karine Massé
- Department of Biological Sciences, Warwick University, Coventry CV4 7AL, UK
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Abstract
MHC class I-restricted CD8(+) T cells are necessary to mount an immune response against Mycobacterium tuberculosis. M. tuberculosis antigens can enter MHC class I cross-processing pathways through a number of different mechanisms, including via the uptake of antigen-containing apoptotic vesicles released by infected cells. A study in this issue of the JCI by Hinchey and colleagues shows that M. tuberculosis inhibits host cell apoptosis and thus may interfere with optimal cross-priming and action of CD8(+) T cells (see the related article beginning on page 2279). M. tuberculosis genetically modified to induce apoptosis is shown to be more effective in priming CD8(+) T cells in vivo and therefore may be a more effective vaccine against tuberculosis than the currently utilized M. bovis BCG vaccine.
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Affiliation(s)
- W Henry Boom
- Tuberculosis Research Unit, Case Western Reserve University and University Hospitals' Case Medical Center, Cleveland, Ohio 44106-4984, USA.
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Abstract
Mutations in the DNA mismatch repair (MMR) genes are associated with the inheritance of hereditary non-polyposis colorectal cancer, also known as Lynch syndrome, a cancer syndrome with an average age at onset of 44. Individuals presenting with colorectal cancer are diagnosed with Lynch I, whereas individuals who present with extra-colonic tumors (such as endometrial, stomach, etc.) are identified as patients with Lynch syndrome II. Recently, 30 families have been reported with inheritance of biallelic mutations in the MMR genes. Here we summarize the phenotype of individuals with inheritance of homozygous or compound heterozygous mutations in the MMR genes that result in a complete lack of protein or greatly compromised protein function. In contrast to individuals with Lynch syndrome I and II, individuals with no MMR function present with childhood onset of hematological and brain malignancies, whereas residual MMR function can also result in gastrointestinal cancers and an age of onset in the second to fourth decade. Individuals with biallelic MMR mutations often present with café-au-lait spots, regardless of the level of MMR function remaining. Thus, the inheritance of two MMR gene mutations is a separate entity from Lynch I or II or the subtypes Turcot and Muir-Torre.
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Affiliation(s)
- K E A Felton
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
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Rao VA, Conti C, Guirouilh-Barbat J, Nakamura A, Miao ZH, Davies SL, Saccá B, Hickson ID, Bensimon A, Pommier Y. Endogenous γ-H2AX-ATM-Chk2 Checkpoint Activation in Bloom's Syndrome Helicase–Deficient Cells Is Related to DNA Replication Arrested Forks. Mol Cancer Res 2007; 5:713-24. [PMID: 17634426 DOI: 10.1158/1541-7786.mcr-07-0028] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Bloom syndrome helicase (BLM) is critical for genomic stability. A defect in BLM activity results in the cancer-predisposing Bloom syndrome (BS). Here, we report that BLM-deficient cell lines and primary fibroblasts display an endogenously activated DNA double-strand break checkpoint response with prominent levels of phosphorylated histone H2AX (gamma-H2AX), Chk2 (p(T68)Chk2), and ATM (p(S1981)ATM) colocalizing in nuclear foci. Interestingly, the mitotic fraction of gamma-H2AX foci did not seem to be higher in BLM-deficient cells, indicating that these lesions form transiently during interphase. Pulse labeling with iododeoxyuridine and immunofluorescence microscopy showed the colocalization of gamma-H2AX, ATM, and Chk2 together with replication foci. Those foci costained for Rad51, indicating homologous recombination at these replication sites. We therefore analyzed replication in BS cells using a single molecule approach on combed DNA fibers. In addition to a higher frequency of replication fork barriers, BS cells displayed a reduced average fork velocity and global reduction of interorigin distances indicative of an elevated frequency of origin firing. Because BS is one of the most penetrant cancer-predisposing hereditary diseases, it is likely that the lack of BLM engages the cells in a situation similar to precancerous tissues with replication stress. To our knowledge, this is the first report of high ATM-Chk2 kinase activation and its linkage to replication defects in a BS model.
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Affiliation(s)
- V Ashutosh Rao
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, U.S. Department of Health and Human Services, Bethesda, Maryland, USA
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Sillibourne JE, Delaval B, Redick S, Sinha M, Doxsey SJ. Chromatin remodeling proteins interact with pericentrin to regulate centrosome integrity. Mol Biol Cell 2007; 18:3667-80. [PMID: 17626165 PMCID: PMC1951766 DOI: 10.1091/mbc.e06-07-0604] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Pericentrin is an integral centrosomal component that anchors regulatory and structural molecules to centrosomes. In a yeast two-hybrid screen with pericentrin we identified chromodomain helicase DNA-binding protein 4 (CHD4/Mi2beta). CHD4 is part of the multiprotein nucleosome remodeling deacetylase (NuRD) complex. We show that many NuRD components interacted with pericentrin by coimmunoprecipitation and that they localized to centrosomes and midbodies. Overexpression of the pericentrin-binding domain of CHD4 or another family member (CHD3) dissociated pericentrin from centrosomes. Depletion of CHD3, but not CHD4, by RNA interference dissociated pericentrin and gamma-tubulin from centrosomes. Microtubule nucleation/organization, cell morphology, and nuclear centration were disrupted in CHD3-depleted cells. Spindles were disorganized, the majority showing a prometaphase-like configuration. Time-lapse imaging revealed mitotic failure before chromosome segregation and cytokinesis failure. We conclude that pericentrin forms complexes with CHD3 and CHD4, but a distinct CHD3-pericentrin complex is required for centrosomal anchoring of pericentrin/gamma-tubulin and for centrosome integrity.
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Nagasaka H, Chiba H, Hui SP, Takikawa H, Miida T, Takayanagi M, Yorifuji T, Hasegawa M, Ota A, Hirano KI, Kikuchi H, Tsukahara H, Kobayashi K. Depletion of high-density lipoprotein and appearance of triglyceride-rich low-density lipoprotein in a Japanese patient with FIC1 deficiency manifesting benign recurrent intrahepatic cholestasis. J Pediatr Gastroenterol Nutr 2007; 45:96-105. [PMID: 17592371 DOI: 10.1097/mpg.0b013e3180331df9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVE Lipoprotein metabolism in FIC1 deficiency due to ATP8B1 mutations has never been studied sufficiently. This study was performed to investigate the detailed lipoprotein metabolism in benign recurrent intrahepatic cholestasis (BRIC) caused by FIC1 deficiency. PATIENTS AND METHODS Lipoprotein profile and major lipoprotein regulators such as lecithin:cholesterol acyltransferase (LCAT), hepatic triglyceride lipase (HTGL), lipoprotein lipase, and cholesteryl ester transfer protein in a Japanese patient with BRIC were serially examined during a bout of cholestasis. Liver expression of farnesoid X receptor (FXR), which suppresses high-density lipoprotein (HDL) generation, was also examined. RESULTS Hypercholesterolemia and lipoprotein X accumulation were never observed throughout this study. When the cholestasis was severe, triglyceride-rich low-density lipoprotein (LDL) accounted for most of the plasma lipoproteins whereas HDL was hardly detectable. Concurrently, activities of all regulators were decreased, together with decreases of the serum parameter for liver protein synthesis. In particular, suppressions of LCAT and HTGL activities were severe and greatly contributed to the appearance of triglyceride-rich LDL. As the cholestasis improved, this LDL gradually transformed into normal LDL with the recoveries of LCAT and HTGL activities. The activities of all regulators for the last 1 to 2 months were normal but HDL remained depleted. His liver showed low FXR expression compared with control livers. CONCLUSIONS The present study showed an appearance of triglyceride-rich LDL due to suppressions of LCAT and HTGL activities and a depletion of HDL that is not able to be explained by lipoprotein regulators or FXR in our patient.
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Affiliation(s)
- Hironori Nagasaka
- Division of Metabolism, Chiba Children's Hospital, Heta Cho, Midori-Ku, Chiba, Japan.
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Chan KL, North PS, Hickson ID. BLM is required for faithful chromosome segregation and its localization defines a class of ultrafine anaphase bridges. EMBO J 2007; 26:3397-409. [PMID: 17599064 PMCID: PMC1933408 DOI: 10.1038/sj.emboj.7601777] [Citation(s) in RCA: 323] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Accepted: 05/31/2007] [Indexed: 11/08/2022] Open
Abstract
Mutations in BLM cause Bloom's syndrome, a disorder associated with cancer predisposition and chromosomal instability. We investigated whether BLM plays a role in ensuring the faithful chromosome segregation in human cells. We show that BLM-defective cells display a higher frequency of anaphase bridges and lagging chromatin than do isogenic corrected derivatives that eptopically express the BLM protein. In normal cells undergoing mitosis, BLM protein localizes to anaphase bridges, where it colocalizes with its cellular partners, topoisomerase IIIalpha and hRMI1 (BLAP75). Using BLM staining as a marker, we have identified a class of ultrafine DNA bridges in anaphase that are surprisingly prevalent in the anaphase population of normal human cells. These so-called BLM-DNA bridges, which also stain for the PICH protein, frequently link centromeric loci, and are present at an elevated frequency in cells lacking BLM. On the basis of these results, we propose that sister-chromatid disjunction is often incomplete in human cells even after the onset of anaphase. We present a model for the action of BLM in ensuring complete sister chromatid decatenation in anaphase.
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Affiliation(s)
- Kok-Lung Chan
- Cancer Research UK Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Phillip S North
- Cancer Research UK Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Ian D Hickson
- Cancer Research UK Laboratories, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
- Cancer Research UK Oxford Cancer Centre, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK. Tel.: +44 1865 222 417; Fax: +44 1865 222 431; E-mail:
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Abstract
Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome types I and II, and the related subtypes Turcot and Muir-Torre syndrome, have all been associated with inheritance of germ line mutations in the DNA mismatch repair (MMR) genes. Fifty individuals have recently been identified with an early onset of a different spectrum of cancers associated with inheritance of two MMR mutations--resulting either in a constitutive loss of MMR function, or greatly impaired MMR function. In contrast to Lynch I and II individuals, individuals with inheritance of homozygous or compound heterozygous mutations in the MMR genes that result in a complete lack of protein, present with hematological and brain malignancies in the first decade of life. Biallelic mutations with compromised but residual protein function present with a broader spectrum of cancers (brain, hematological or gastrointestinal) in the second to fourth decades of life. We propose that inheritance of two MMR mutations in an individual and the unique tumor spectrum that occurs with an early onset should be defined separately from Lynch syndrome I and II, or the subtypes Turcot and Muir-Torre. We suggest Lynch III as an appropriate name for identifying individuals with constitutively compromised MMR associated with biallelic mutations.
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Affiliation(s)
- K E A Felton
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
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Müller JMM, Deinhardt K, Rosewell I, Warren G, Shima DT. Targeted deletion of p97 (VCP/CDC48) in mouse results in early embryonic lethality. Biochem Biophys Res Commun 2007; 354:459-65. [PMID: 17239345 DOI: 10.1016/j.bbrc.2006.12.206] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 12/31/2006] [Indexed: 11/17/2022]
Abstract
The highly conserved AAA ATPase p97 (VCP/CDC48) has well-established roles in cell cycle progression, proteasome degradation and membrane dynamics. Gene disruption in Saccromyces cerevisiae, Drosophila melanogaster and Trypanosoma brucei demonstrated that p97 is essential in unicellular and multicellular organisms. To explore the requirement for p97 in mammalian cell function and embryogenesis, we disrupted the p97 locus by gene targeting. Heterozygous p97+/- mice were indistinguishable from their wild-type littermates, whereas homozygous mutants did not survive to birth and died at a peri-implantation stage. These results show that p97 is an essential gene for early mouse development.
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Affiliation(s)
- J M M Müller
- Endothelial Cell Biology Laboratory, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
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Abstract
The RecQ family of DNA helicases consists of specialized DNA unwinding enzymes that promote genomic stability through their participation in a number of cellular processes, including DNA replication, recombination, DNA damage signaling, and DNA repair pathways. Mutations resulting in the inactivation of some but not all members of the RecQ helicase family can lead to human syndromes which are characterized by marked chromosomal instability and an increased predisposition to cancer. An evolutionarily conserved interaction between RecQ helicases and topoisomerase 3s has been established, and this interaction is important in the regulation of recombination and genomic stability. Topoisomerases are critical in the cell because they relieve helical stress that arises when DNA is unwound. Topoisomerases function by breaking and rejoining DNA. By inhibition of the rejoining function, topoisomerase inhibitors are potent chemotherapeutic agents that have been used successfully in the treatment of hematologic malignancies and other cancers. This review discusses the roles of RecQ helicases in genomic stability, the interplay between RecQ helicases and topoisomerase 3s, and current and future prospects for targeting these interactions to develop novel anticancer therapies.
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Affiliation(s)
- Leslie L Woo
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
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Depienne C, Fedirko E, Forlani S, Cazeneuve C, Ribaï P, Feki I, Tallaksen C, Nguyen K, Stankoff B, Ruberg M, Stevanin G, Durr A, Brice A. Exon deletions of SPG4 are a frequent cause of hereditary spastic paraplegia. J Med Genet 2006; 44:281-4. [PMID: 17098887 PMCID: PMC2598038 DOI: 10.1136/jmg.2006.046425] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Point mutations in SPG4, the gene encoding spastin, are a frequent cause of autosomal dominant hereditary spastic paraplegia (AD-HSP). However, standard methods for genetic analyses fail to detect exonic microdeletions. METHODS 121 mutation-negative probands were screened for rearrangements in SPG4 by multiplex ligation-dependent probe amplification. RESULTS 24 patients with 16 different heterozygotic exon deletions in SPG4 (20%) were identified, ranging from one exon to the whole coding sequence. Comparison with 78 patients with point mutations showed a similar clinical picture but an earlier age at onset. CONCLUSIONS Exon deletions in SPG4 are as frequent as point mutations, and SPG4 is responsible for 40% of AD-HSP.
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Abstract
The nucleoprotein filament formed by Rad51 polymerization on single-stranded DNA is essential for homologous pairing and strand exchange. ATP binding is required for Rad51 nucleoprotein filament formation and strand exchange, but ATP hydrolysis is not required for these functions in vitro. Previous studies have shown that a yeast strain expressing the rad51-K191R allele is sensitive to ionizing radiation, suggesting an important role for ATP hydrolysis in vivo. The recruitment of Rad51-K191R to double-strand breaks is defective in vivo, and this phenotype can be suppressed by elimination of the Srs2 helicase, an antagonist of Rad51 filament formation. The phenotype of the rad51-K191R strain is also suppressed by overexpression of Rad54. In vitro, the Rad51-K191R protein exhibits a slight decrease in binding to DNA, consistent with the defect in presynaptic filament formation. However, the rad51-K191R mutation is dominant in heterozygous diploids, indicating that the defect is not due simply to reduced affinity for DNA. We suggest the Rad51-K191R protein either forms an altered filament or is defective in turnover, resulting in a reduced pool of free protein available for DNA binding.
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Affiliation(s)
- Cindy W Fung
- Graduate Program in Cellular, Molecular and Biophysical Studies, Columbia University Medical Center, New York, NY 10032, USA
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36
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Lindstrom KC, Vary JC, Parthun MR, Delrow J, Tsukiyama T. Isw1 functions in parallel with the NuA4 and Swr1 complexes in stress-induced gene repression. Mol Cell Biol 2006; 26:6117-29. [PMID: 16880522 PMCID: PMC1592817 DOI: 10.1128/mcb.00642-06] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The packaging of DNA into chromatin allows eukaryotic cells to organize and compact their genomes but also creates an environment that is generally repressive to nuclear processes that depend upon DNA accessibility. There are several classes of enzymes that modulate the primary structure of chromatin to regulate various DNA-dependent processes. The biochemical activities of the yeast Isw1 ATP-dependent chromatin-remodeling enzyme have been well characterized in vitro, but little is known about how these activities are utilized in vivo. In this work, we sought to discern genetic backgrounds that require Isw1 activity for normal growth. We identified a three-way genetic interaction among Isw1, the NuA4 histone acetyltransferase complex, and the Swr1 histone replacement complex. Transcription microarray analysis revealed parallel functions for these three chromatin-modifying factors in the regulation of TATA-containing genes, including the repression of a large number of stress-induced genes under normal growth conditions. In contrast to a recruitment-based model, we find that the NuA4 and Swr1 complexes act throughout the genome while only a specific subset of the genome shows alterations in transcription.
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Affiliation(s)
- Kimberly C Lindstrom
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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37
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Abstract
RecQ helicase BLM-deficient cells are characteristically hypersensitive to 4-nitroquinoline-1-oxide (4NQO). We recently reported that isogenic BLM-deficient cells (PNSG13) are more sensitive than BLM-complemented cells (PNSF5) to camptothecin, which specifically traps topoisomerase I cleavage complexes (Top1cc). We now report that PNSG13 are also 3.5-fold more sensitive to 4NQO compared with PNSF5 and that 4NQO induces higher levels of Top1cc and reduced histone gamma-H2AX in PSNG13 than in PNSF5. Similarly, 4NQO induces more Top1cc in primary fibroblasts from a patient with Bloom syndrome than in normal human fibroblasts. 4NQO also induces Top1cc in colon cancer HCT116 and HT29 cells in a time- and concentration-dependent fashion. Of note, distinct from camptothecin, the Top1cc produced by 4NQO accumulate progressively after 4NQO addition and persist following 4NQO removal. The Top1cc induced by 4NQO are detectable by alkaline elution. To examine the functional relevance of the Top1cc induced by 4NQO, we used two stable topoisomerase I small interfering RNA (siRNA) cell lines derived from HCT116 and MCF7 cells. Both topoisomerase I siRNA cell lines are resistant to 4NQO, indicating that Top1cc contribute to the cellular activity of 4NQO. Collectively, these data show that 4NQO is an effective inducer of cellular Top1cc. Because 4NQO does not directly trap Top1cc in biochemical assays, we propose that active metabolites of 4NQO trap Top1cc by forming DNA adducts. Induction of Top1cc and histone gamma-H2AX by 4NQO may contribute to the cellular effects of 4NQO, including its selective activity toward RecQ helicase BLM-deficient cells.
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Affiliation(s)
- Ze-Hong Miao
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute/NIH, Bethesda, MD 20892, USA
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38
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Wood JD, Landers JA, Bingley M, McDermott CJ, Thomas-McArthur V, Gleadall LJ, Shaw PJ, Cunliffe VT. The microtubule-severing protein Spastin is essential for axon outgrowth in the zebrafish embryo. Hum Mol Genet 2006; 15:2763-71. [PMID: 16893913 DOI: 10.1093/hmg/ddl212] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hereditary spastic paraplegia (HSP) is a collection of neurological disorders characterized by developmental failure or degeneration of motor axons in the corticospinal tract and progressive lower limb spasticity. SPG4 mutations are the most common cause of autosomal dominant HSP and Spastin (the SPG4 gene product) is a microtubule severing protein that shares homology with katanin, the microtubule severing activity of which promotes axon growth in cultured neurons. Given the sequence and functional similarity between spastin and katanin, we hypothesized that spastin promotes the dynamic disassembly and remodelling of microtubules required for robust, properly directed motor axon outgrowth. To investigate this hypothesis, we cloned the zebrafish spg4 orthologue and used morpholino antisense oligonucleotides directed against the translation start site and the intron 7-8 splice donor site to knock down spastin function in the developing zebrafish embryo. Reduced spg4 function caused dramatic defects in motor axon outgrowth without affecting the events driving the initial specification of motor neurones. Other neuronal subtypes also exhibited a requirement for spg4 function, since spg4 knock down caused both widespread defects in neuronal connectivity and extensive CNS-specific apoptosis. Our results reveal a critical requirement for spastin to promote axonal outgrowth during embryonic development, and they validate the zebrafish embryo as a novel model system to dissect the pathogenetic mechanisms underlying HSP. Taken together with other recent studies, our findings suggest that axon outgrowth defects may be a common feature of childhood SPG3A and SPG4 cases.
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Affiliation(s)
- Jonathan D Wood
- MRC Centre Development for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, UK
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39
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Pérez-Victoria FJ, Sánchez-Cañete MP, Castanys S, Gamarro F. Phospholipid Translocation and Miltefosine Potency Require Both L. donovani Miltefosine Transporter and the New Protein LdRos3 in Leishmania Parasites. J Biol Chem 2006; 281:23766-75. [PMID: 16785229 DOI: 10.1074/jbc.m605214200] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The antitumor drug miltefosine has been recently approved as the first oral drug active against visceral leishmaniasis. We have previously identified the L. donovani miltefosine transporter (LdMT) as a P-type ATPase involved in phospholipid translocation at the plasma membrane of Leishmania parasites. Here we show that this protein is essential but not sufficient for the phospholipid translocation activity and, thus, for the potency of the drug. Based on recent findings in yeast, we have identified the putative beta subunit of LdMT, named LdRos3, as another protein factor required for the translocation activity. LdRos3 belongs to the CDC50/Lem3 family, proposed as likely beta subunits for P4-ATPases. The phenotype of LdRos3-defective parasites was identical to that of the LdMT-/-, including a defect in the uptake of 7-nitrobenz-2-oxa-1,3-diazol-4-yl-amino)-phosphatidylserine, generally considered as not affected in Lem3p-deficient yeast. Both LdMT and LdRos3 normally localized to the plasma membrane but were retained inside the endoplasmic reticulum in the absence of the other protein or when inactivating point mutations were introduced in LdMT. Modulating the expression levels of either protein independently, we show that any one of them could behave as the protein limiting the level of flippase activity. Thus, LdMT and LdRos3 seem to form part of the same translocation machinery that determines flippase activity and miltefosine sensitivity in Leishmania, further supporting the consideration of CDC50/Lem3 proteins as beta subunits required for the normal functioning of P4-ATPases.
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Affiliation(s)
- F Javier Pérez-Victoria
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Avda. del Conocimiento s/n 18100 Armilla, Granada, Spain
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Suzuki T, Minehata KI, Akagi K, Jenkins NA, Copeland NG. Tumor suppressor gene identification using retroviral insertional mutagenesis in Blm-deficient mice. EMBO J 2006; 25:3422-31. [PMID: 16858412 PMCID: PMC1523184 DOI: 10.1038/sj.emboj.7601215] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 06/06/2006] [Indexed: 11/09/2022] Open
Abstract
Retroviral insertional mutagenesis preferentially identifies oncogenes rather than tumor suppressor (TS) genes, presumably because a single retroviral-induced mutation is sufficient to activate an oncogene and initiate a tumor, whereas two mutations are needed to inactivate a TS gene. Here we show that TS genes can be identified by insertional mutagenesis when the screens are performed in Blm-deficient backgrounds. Blm-deficient mice, like Bloom syndrome patients, have increased frequencies of mitotic recombination owing to a mutation in the RecQ protein-like-3 helicase gene. This increased mitotic recombination increases the likelihood that an insertional mutation in one allele of a TS gene will become homozygoused by non-sister chromatid exchange and the homozygosity of the insertion provides a marker for identifying the TS gene. We also show that known as well as novel TS genes can be identified by insertional mutagenesis in Blm-deficient mice and identify two JmjC family proteins that contribute to genome stability in species as evolutionarily diverse as mammals and Caenorhabditis elegans.
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Affiliation(s)
- Takeshi Suzuki
- Cancer Genetic Unit, Horizontal Medical Research Organization, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ken-ichi Minehata
- Cancer Genetic Unit, Horizontal Medical Research Organization, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Keiko Akagi
- Mouse Cancer Genetics Program, National Cancer Institute, Center for Cancer Research, Frederick, MD, USA
| | - Nancy A Jenkins
- Mouse Cancer Genetics Program, National Cancer Institute, Center for Cancer Research, Frederick, MD, USA
| | - Neal G Copeland
- Mouse Cancer Genetics Program, National Cancer Institute, Center for Cancer Research, Frederick, MD, USA
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Paulusma CC, Groen A, Kunne C, Ho-Mok KS, Spijkerboer AL, Rudi de Waart D, Hoek FJ, Vreeling H, Hoeben KA, van Marle J, Pawlikowska L, Bull LN, Hofmann AF, Knisely AS, Oude Elferink RPJ. Atp8b1 deficiency in mice reduces resistance of the canalicular membrane to hydrophobic bile salts and impairs bile salt transport. Hepatology 2006; 44:195-204. [PMID: 16799980 DOI: 10.1002/hep.21212] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Progressive familial intrahepatic cholestasis type 1 (PFIC1, Byler disease, OMIM 211600) is a severe inherited liver disease caused by mutations in ATP8B1. ATP8B1 is a member of the type 4 subfamily of P-type ATPases, which are phospholipid flippases. PFIC1 patients generally develop end-stage liver disease before the second decade of life. The disease is characterized by impaired biliary bile salt excretion, but the mechanism whereby impaired ATP8B1 function results in cholestasis is unclear. In a mouse model for PFIC1, we observed decreased resistance of the hepatocanalicular membrane to hydrophobic bile salts as evidenced by enhanced biliary recovery of phosphatidylserine, cholesterol, and ectoenzymes. In liver specimens from PFIC1 patients, but not in those from control subjects, ectoenzyme expression at the canalicular membrane was markedly deficient. In isolated mouse livers Atp8b1 deficiency impaired the transport of hydrophobic bile salts into bile. In conclusion, our study shows that Atp8b1 deficiency causes loss of canalicular phospholipid membrane asymmetry that in turn renders the canalicular membrane less resistant toward hydrophobic bile salts. The loss of phospholipid asymmetry may subsequently impair bile salt transport and cause cholestasis.
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Affiliation(s)
- Coen C Paulusma
- Amsterdam Liver Center, Department of Experimental Hepatology, Academic Medical Center, Amsterdam, the Netherlands.
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Abstract
The maintenance of transbilayer distribution of phospholipids is crucial for proper cell function. Intramembrane transport of lipids is mediated by three activities termed floppases, flippases, and scramblases. Members of the ATP-binding cassette transporter family and P-type ATPase superfamily have been implicated in the translocation of lipids. The importance of these activities is exemplified by several severe human inherited disorders that are caused by defects in intramembranous transport of lipids. In order to elucidate the molecular mechanisms that underlie these disorders, the combination of in vivo, biochemical, and structural analyses on intramembrane transporters is crucial.
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Affiliation(s)
- Coen C Paulusma
- Amsterdam Liver Center, Department of Experimental Hepatology, Academic Medical Center, Meibergdreef 69-71, S-1-168, 1105 BK Amsterdam, The Netherlands.
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Werner SR, Prahalad AK, Yang J, Hock JM. RECQL4-deficient cells are hypersensitive to oxidative stress/damage: Insights for osteosarcoma prevalence and heterogeneity in Rothmund-Thomson syndrome. Biochem Biophys Res Commun 2006; 345:403-9. [PMID: 16678792 DOI: 10.1016/j.bbrc.2006.04.093] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Accepted: 04/15/2006] [Indexed: 10/24/2022]
Abstract
Rothmund-Thomson syndrome (RTS) is a heterogeneous disease, associated with increased prevalence of osteosarcoma in very young patients with a mutated RECQL4 gene. In this study, we tested the ability of RECQL4 deficient fibroblasts, derived from a RTS patient to recover from hydrogen peroxide (H(2)O(2))-induced oxidative stress/damage. Immunoperoxidase staining for 8-oxo-deoxyguanosine (8-oxo-dG) formation in RTS and normal human fibroblasts were compared to assess DNA damage. We determined DNA synthesis, cell growth, cell cycle distribution, and viability in RTS and normal human fibroblasts before and after H(2)O(2) treatment. H(2)O(2) induces 8-oxo-dG formation in both RTS and normal fibroblasts. In normal human fibroblasts, RECQL4 was predominantly localized to cytoplasm; nuclear translocation and foci formation occurred in response to oxidant stimulation. After recovery from oxidant exposure, viable RTS fibroblasts showed irreversible growth arrest compared to normal fibroblasts. DNA synthesis decreased significantly in treated RTS cells, with concomitant reduction of cells in the S-phase. These results suggest that enhanced oxidant sensitivity in RECQL4 deficient fibroblasts derived from RTS patients could be attributed to abnormal DNA metabolism and proliferation failure. The ramifications of these findings on osteosarcoma prevalence and heterogeneity in RTS are discussed.
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Affiliation(s)
- Sean R Werner
- Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA
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Hegan DC, Narayanan L, Jirik FR, Edelmann W, Liskay RM, Glazer PM. Differing patterns of genetic instability in mice deficient in the mismatch repair genes Pms2, Mlh1, Msh2, Msh3 and Msh6. Carcinogenesis 2006; 27:2402-8. [PMID: 16728433 PMCID: PMC2612936 DOI: 10.1093/carcin/bgl079] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Defects in genes associated with DNA mismatch repair (MMR) have been linked to hereditary colon cancer. Because the MMR pathway includes multiple factors with both overlapping and divergent functions, we sought to compare the impact of deficiencies in each of several MMR genes on genetic instability using a collection of knock-out mouse models. We investigated mutation frequencies and patterns in MMR-deficient mice using two transgenic reporter genes, supFG1 and cII, in the context of mice deficient for Pms2, Mlh1, Msh2, Msh3 or Msh6 or both Msh2 and Msh3 or both Msh3 and Msh6. We found that the mean mutation frequencies of all of the MMR-deficient mice were significantly higher than the mean mutation frequencies of wild-type mice. Mlh1-deficient mice and Msh2-deficient mice had the highest mutation frequencies in a comparison of the single nullizygous mice. Of all the mice studied, mice nullizygous for both Msh2 and Msh3 and those nullizygous for both Msh3 and Msh6 displayed the greatest overall increases in mutation frequencies compared with wild-type mice. Sequence analysis of the mutated reporter genes revealed significant differences between the individual groups of MMR-deficient mice. Taken together, our results further characterize the functions of the MMR factors in mutation avoidance and provide in vivo correlation to biochemical models of the MMR pathway.
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Affiliation(s)
- Denise Campisi Hegan
- Department of Therapeutic Radiology, Yale University School of Medicine, PO Box 208040, New Haven, CT 06520-8040, USA
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Kajitani K, Yamaguchi H, Dan Y, Furuichi M, Kang D, Nakabeppu Y. MTH1, an oxidized purine nucleoside triphosphatase, suppresses the accumulation of oxidative damage of nucleic acids in the hippocampal microglia during kainate-induced excitotoxicity. J Neurosci 2006; 26:1688-98. [PMID: 16467516 PMCID: PMC6793619 DOI: 10.1523/jneurosci.4948-05.2006] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Enhanced oxidative stress has been implicated in the excitotoxicity of the CNS, and 8-oxo-7,8-dihydro-guanine (8-oxoG), a major type of oxidative damage in nucleic acids, was reported to be accumulated in the rat hippocampus after kainate administration. We herein showed that the 8-oxoG levels in mitochondrial DNA and cellular RNA increased significantly in the CA3 subregion of the mouse hippocampus 6-12 h after kainate administration but returned to basal levels within a few days. Laser-scanning confocal microscopy revealed the 8-oxoG accumulation in mitochondrial DNA to be remarkable in CA3 microglia, whereas that in nuclear DNA or cellular RNA was also detected in the CA3 pyramidal cells and astrocytes. 8-oxoG accumulation in cellular DNA or RNA should be suppressed by MutT homolog 1 (MTH1) with 8-oxo-dGTPase (8-oxo-7,8-dihydro-2'-deoxyguanosine triphosphatase) activity and 8-oxoG-DNA glycosylase 1 (OGG1) with 8-oxoG DNA glycosylase activity. We thus examined the expression level of MTH1 and OGG1 in the mouse hippocampus after kainate administration. The Mth1 mRNA level decreased soon after kainate administration and then quickly recovered beyond the basal level, and a continuously increased MTH1 protein level was observed, whereas the Ogg1 mRNA level remained constant. MTH1-null and wild-type mice exhibited a similar degree of CA3 neuron loss after kainate administration; however, the 8-oxoG levels that accumulated in mitochondrial DNA and cellular RNA in the CA3 microglia significantly increased in the MTH1-null mice in comparison with wild-type mice, thus demonstrating that MTH1 efficiently suppresses the accumulation of 8-oxoG in both cellular DNA and RNA in the hippocampus, especially in microglia, caused by excitotoxicity.
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46
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Mrácek T, Pecina P, Vojtísková A, Kalous M, Sebesta O, Houstek J. Two components in pathogenic mechanism of mitochondrial ATPase deficiency: energy deprivation and ROS production. Exp Gerontol 2006; 41:683-7. [PMID: 16581217 DOI: 10.1016/j.exger.2006.02.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 02/08/2006] [Accepted: 02/21/2006] [Indexed: 10/24/2022]
Abstract
Isolated defects of mitochondrial ATPase due to diminished biosynthesis of the enzyme represent new class of severe mitochondrial diseases of nuclear origin. The primary cause of decreased cellular content of ATPase appears to be a problem in assembly of the F1 catalytic part of the enzyme. With the aim to elucidate how the low ATPase content affects mitochondrial energy provision and ROS production, we have investigated fibroblasts from patients with ATPase decrease to 10-30%. Measurements of cellular respiration showed pronounced decrease in ATPase capacity for basal respiration, mitochondrial ATP synthesis was decreased to 26-33%. Cytofluorometric analysis using TMRM revealed altered discharge of mitochondrial membrane potential (DeltaPsim) in patient cells, which was 20 mV increased at state 3-ADP. Analysis of ROS production by CM-H2DCFDA demonstrated 2-fold increase in ROS production in patient cells compared to controls. ROS production rate was sensitive to uncoupler (FCCP) and thus apparently related to increased DeltaPsim. Our studies clearly demonstrate that low ATPase content and decreased mitochondrial ATP production lead to high values of DeltaPsim and are associated with activation of ROS generation by the mitochondrial respiratory chain. In conclusion, both the energetic deprivation and increased oxidative stress are important components of the pathogenic mechanism of ATPase disorders.
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Affiliation(s)
- Tomás Mrácek
- Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4-Krc, Czech Republic
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Shaddock JG, Dobrovolsky VN, Mittelstaedt RA, Heflich RH, Parsons BL. Frequency and types of spontaneous Hprt lymphocyte mutations in Pms2-deficient mice. Mutat Res 2006; 595:69-79. [PMID: 16336979 DOI: 10.1016/j.mrfmmm.2005.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 07/11/2005] [Accepted: 10/15/2005] [Indexed: 05/05/2023]
Abstract
Deficiencies in DNA mismatch repair (MMR) result in predisposition to neoplasia in both rodents and humans. Pms2 is one of the several proteins involved in the eukaryotic MMR system. In order to determine the effect of Pms2-deficiency on mutation, we measured mutant frequencies in the endogenous Hprt gene of lymphocytes from male Pms2(-/-), Pms2(+/-), and Pms2(+/+) mice. Spleens were removed from mice of various ages and lymphocytes isolated from spleens were cultured to determine the frequency of 6-thioguanine-resistant mutants. Mean mutant frequencies in Pms2(-/-) mice at 6, 10, 18, and 34 weeks of age [42.6 x 10(-6) (n=6), 38.5 x 10(-6) (n=6), 58.2 x 10(-6) (n=9), and 49.1 x 10(-6) (n=5), respectively] were significantly higher than those of comparably aged Pms2(+/+) and Pms2(+/-) mice (all less than 3 x 10(-6)). Mutant clones from the mice were expanded, RNA extracted, and Hprt cDNA amplified by RT-PCR. DNA sequencing analysis of 221 mutant cDNAs from the three different Pms2 genotypes identified 182 clones with independent mutations, including five clones that contained multiple mutations. When compared to the mutational spectrum observed in Pms2(+/+) and Pms2(+/-) mice, the mutational spectrum for Pms2(-/-) mice was significantly different. The Pms2(-/-) mutational analysis indicated that loss of the Pms2 protein causes increases in the frequencies of strand-slippage-type frameshift mutations and of A:T --> G:C transitions in the Hprt gene. The absolute frequencies of A:T --> G:C transitions in MMR-deficient mice suggest increases in this mutation may be a common feature of MMR-deficient mice, not just of Pms2-deficient mice, and may be related to the cancer predisposition that results from loss of MMR function.
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Affiliation(s)
- Joseph G Shaddock
- Division of Genetic and Reproductive Toxicology, National Center for Toxicological Research, US FDA, Jefferson, AR 72079, USA
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Orso G, Martinuzzi A, Rossetto MG, Sartori E, Feany M, Daga A. Disease-related phenotypes in a Drosophila model of hereditary spastic paraplegia are ameliorated by treatment with vinblastine. J Clin Invest 2006; 115:3026-34. [PMID: 16276413 PMCID: PMC1265857 DOI: 10.1172/jci24694] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Accepted: 08/23/2005] [Indexed: 11/17/2022] Open
Abstract
Hereditary spastic paraplegias (HSPs) are a group of neurodegenerative diseases characterized by progressive weakness and spasticity of the lower limbs. Dominant mutations in the human SPG4 gene, encoding spastin, are responsible for the most frequent form of HSP. Spastin is an ATPase that binds microtubules and localizes to the spindle pole and distal axon in mammalian cell lines. Furthermore, its Drosophila homolog, Drosophila spastin (Dspastin), has been recently shown to regulate microtubule stability and synaptic function at the Drosophila larval neuromuscular junction. Here we report the generation of a spastin-linked HSP animal model and show that in Drosophila, neural knockdown of Dspastin and, conversely, neural overexpression of Dspastin containing a conserved pathogenic mutation both recapitulate some phenotypic aspects of the human disease, including adult onset, locomotor impairment, and neurodegeneration. At the subcellular level, neuronal expression of both Dspastin RNA interference and mutant Dspastin cause an excessive stabilization of microtubules in the neuromuscular junction synapse. In addition, we provide evidence that administration of the microtubule targeting drug vinblastine significantly attenuates these phenotypes in vivo. Our findings demonstrate that loss of spastin function elicits HSP-like phenotypes in Drosophila, provide novel insights into the molecular mechanism of spastin mutations, and raise the possibility that therapy with Vinca alkaloids may be efficacious in spastin-associated HSP and other disorders related to microtubule dysfunction.
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Affiliation(s)
- Genny Orso
- Dulbecco Telethon Institute and Department of Pharmacology, University of Padova, Padova, Italy
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Wilson C, Idziaszczyk S, Colley J, Humphreys V, Guy C, Maynard J, Sampson JR, Cheadle JP. Induction of renal tumorigenesis with elevated levels of somatic loss of heterozygosity in Tsc1+/- mice on a Blm-deficient background. Cancer Res 2006; 65:10179-82. [PMID: 16288003 DOI: 10.1158/0008-5472.can-05-2688] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A Bloom's deficient mouse model (Blm(m3/m3)) has been shown to induce colorectal tumorigenesis when crossed with Apc+/Min mice. Here, we investigated whether the Blm(m3/m3) genotype could induce tumorigenesis in extracolonic tissues in tuberous sclerosis 1-deficient (Tsc1+/-) mice that are predisposed to renal cystadenomas and carcinomas. Genotyping of offspring from Tsc1+/- Blm+/m3 intercrosses showed that a approximately 24% excess of Tsc1+/- over Tsc1+/+ mice died before weaning (P = 0.016), although Blm deficiency had no cumulative effect on Tsc1+/- survival. Tsc1+/- Blm(m3/m3) mice had significantly more macroscopic and microscopic renal lesions at 3 to 6 months compared with Tsc1+/- Blm+/m3 mice (P =0.0003 and 0.0203, respectively), and their tumors showed significantly increased levels of somatic loss of heterozygosity (LOH) of the wild-type Tsc1 (Tsc1wt) allele compared with those from Tsc1+/- Blm+/+ mice (P < 0.0001). Tsc1+/- Blm+/m3 mice did not show significantly more renal lesions compared with Tsc1+/- Blm+/+ animals; however, their lesions still showed significantly increased levels of somatic LOH of the Tsc1wt allele (P = 0.03). Ninety-five percent (19 of 20) of lesions from Tsc1+/- Blm+/m3 mice retained the wild-type Blm (Blm(wt)) allele, indicating that the increased somatic LOH at Tsc1 was mediated by Blm haploinsufficiency. Renal lesions from a Blm-deficient background stained positively with anti-phospho-S6 ribosomal protein (Ser240/244), suggesting that these lesions develop through the normal pathway of Tsc-associated tumorigenesis. This work shows the use of the Blm(m3/m3) mice for inducing renal tumorigenesis, and the high levels (approximately 87%) of LOH in the resultant tumors will help facilitate mapping of loci involved in tumor progression.
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Affiliation(s)
- Catherine Wilson
- Department of Medical Genetics, Cardiff University, Heath Park, Cardiff, United Kingdom
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50
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Kato A, Inoue H. Growth defect and mutator phenotypes of RecQ-deficient Neurospora crassa mutants separately result from homologous recombination and nonhomologous end joining during repair of DNA double-strand breaks. Genetics 2006; 172:113-25. [PMID: 16219790 PMCID: PMC1456140 DOI: 10.1534/genetics.105.041756] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Accepted: 09/29/2005] [Indexed: 11/18/2022] Open
Abstract
RecQ helicases function in the maintenance of genome stability in many organisms. The filamentous fungus Neurospora crassa has two RecQ homologs, QDE3 and RECQ2. We found that the qde-3 recQ2 double mutant showed a severe growth defect. The growth defect was alleviated by mutation in mei-3, the homolog of yeast RAD51, which is required for homologous recombination (HR), suggesting that HR is responsible for this phenotype. We also found that the qde-3 recQ2 double mutant showed a mutator phenotype, yielding mostly deletions. This phenotype was completely suppressed by mutation of mus-52, a homolog of the human KU80 gene that is required for nonhomologous end joining (NHEJ), but was unaffected by mutation of mei-3. The high spontaneous mutation frequency in the double mutant is thus likely to be due to NHEJ acting on an elevated frequency of double-strand breaks (DSBs) and we therefore suggest that QDE3 and RECQ2 maintain chromosome stability by suppressing the formation of spontaneous DSBs.
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Affiliation(s)
- Akihiro Kato
- Laboratory of Genetics, Department of Regulation Biology, Faculty of Science, Saitama University, 338-8570 Saitama, Japan
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