Pathomechanisms of lysosomal storage disorders

Project Leader: Thomas Braulke

  • Project Mucolipidosis II
  • Project Mucolipidosis II

    Mouse model for mucolipidosis II alpha/beta
    We have generated a knock-in mouse model of MLII. In this mouse a single cytosine was inserted in the Gnptab gene (c.3082insC) that is predicted to cause a premature translational termination in the C-terminal conserved region (p.G1028RfsX16) (Figure F 1, Kollmann, et al., 2010). This mutation corresponds to the human c.3145insC mutation (p.G1049RfsX16) detected in an MLII alpha/beta patient (Tiede et al. 2005a).

    Fiure F1: The predicted domain structure of the human alpha/beta-subunit precursor protein of the GlcNAc-1-phosphotransferase
    Lupe zum Vergrößern des Bildes
    F1: Domain structure of the mutant GNPTAB precusor
    Figure F1. The predicted domain structure of the human alpha/beta-subunit precursor protein of the GlcNAc-1-phosphotransferase was compared with the mouse knock-in mutant (p.G1028RfsX16) alpha/beta-subunit precursors. The red part in the C-terminal conserved domain of the mutant alpha/beta-subunit precursor represents the 16 additional amino acids.

    In fibroblasts of this MLII alpha/beta patient no GlcNAc-1-phosphotransferase activity was measured, associate with a strong intracellular reduction of several lysosomal enzyme activities. Mouse embryonic fibroblasts prepared from mutant c.3082insC knock-in mice exhibit intracellular deficiencies and hypersecretion of multiple lysosomal enzyme activities (Figure F2A, Kollmann, et al., 2010) confirming biochemically the MLII-phenotype. Aditionally, no M6P-containing proteins were detectable in cell extracts analyzed by scFv M6P-1 western blotting (Figure F2B, Kollmann, et al., 2010, Müller-Loennies, et al. 2010).

    Figure F2: Relative enzyme activities of lysosomal hydrolases
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    F2: Relative enzyme activities of lysosomal hydrolases
    Figure F2: Relative enzyme activities of lysosomal hydrolases beta-hexosaminidase (beta-hex), alpha-mannosidase (alpha-man) and beta-galactosidase (beta-gal) measured in homogenates of mouse embryonic fibroblasts from c.3082insC knock-in mice in comparison to activities in wild-type fibroblasts. The lysosomal hydrolase activities are reduced in the mutant cells (A). Extracts from c.3082insC knock-in mouse embryonic fibroblasts (ki/ki), from heterozygous (wt/ki) and wild-type fibroblasts (wt/wt) and aliquots of media conditioned for 24 h were analyzed by scFv M6P-1 western blotting. In wild-type cells several M6P-containing proteins were observed whereas in c.3082insC cells no M6P-specific signals were detectable demonstrating the loss of GlcNAc-1-phosphotransferase activity in the knock-in cells (B).

    This mouse model will allow the analysis of pathomechanisms in MLII and related lysosomal storage diseases and the investigation of alternative M6P-independent transport routes to lysosomes.

  • Project Leader

    Thomas Braulke
    Prof. Dr. rer. nat.
    Thomas Braulke
    Phone
    +49 (0) 40 7410 - 54493
    E-mail
    braulke@uke.de
    Further information

    Postdoctoral Fellows

    Malte Klüssendorf
    Dr. rer. nat.
    Malte Klüssendorf
    Phone
    +49 (0) 40 7410 - 51997
    E-mail
    m.kluessendorf@uke.de
    Further information

    Scientific Staff / Graduate Students

    Cand. med. Svenja Krambeck

    Former Members

    Dr. rer. nat. Stephan Tiede
    Dr. med. Elisabeth Schöne
    Dr. rer. nat. Nina Westphal
    Cinta Diez-Ardanuy, PhD
    Dr. rer. nat. Georgia Makrypidi
    Andrea Pirosu, MSc
    Dr. rer. nat. Sandra Markmann
    Dr. med. Takanobu Otomo
    Dr. rer. nat. Katrin Kollmann
    Dr. med. Kathrin Karkmann
    Dr. rer. nat. Melanie Thelen
    Dr. rer. nat. Katrin Marschner
    Dr. med. Bastian Thies
    Dr. rer. nat. Annika Kurze
    Dr. rer. nat. Giovanna Galliciotti
    Cand. med. Anna-Katharina Röchert
    Dr. rer. nat. Anne-Hélène Lebrun
    Inke Stange (TA)
    Dr. med. Nicole Muschol
    Dr. rer. nat. Britta Keyser
    Dr. med. Brit Hofmann
    Manuel-Álvaro Berbis-Moreno
    Monica Castrichini, PhD
    Dipl-Biol. Guillermo F. Jofre
    Dr. rer. nat. Arne Quitsch
    Dr. rer. nat. Sabrina Jabs
    Dr. med. Franziska Stellmer
    Dr. rer. nat. Bettina Koch
    Dr. rer. nat. Bernd Kübler
    Dr. rer. nat. Sandra Oesterreicher
    Dr. rer. nat. Nicola Ott
    Dr. rer. nat. Claudia Heine
    Dr. med. Bettina Bertram
    Dr. med. Victoria Schebek-Fürstenberg

  • Project-relevant Publications

    • Impaired bone remodeling and its correction by combination therapy in a mouse model of mucopolysaccharidosis-I. Kuehn SC, Koehne T, Cornils K, Markmann S, Riedel C, Pestka JM, Schweizer M, Baldauf C, Yorgan TA, Krause M, Keller J, Neven M, Breyer S, Stuecker R, Muschol N, Busse B, Braulke T, Fehse B, Amling M, Schinke T (2015) Hum Mol Genet 24:7075-86 Abstract
    • Mannose 6-phosphorylation of lysosomal enzymes controls B-cell functions. Otomo T, Schweizer M, Kollmann K, Schumacher V, Muschol N, Tolosa E, Mittrücker HW, Braulke T* (2015) J Cell Biol 208:171-180 Abstract
    • Lrp1/LDL Receptor Play Critical Roles in Mannose 6-Phosphate-Independent Lysosomal Enzyme Targeting. Markmann S, Thelen M, Cornils K, Schweizer M, Brocke-Ahmadinejad N, Willnow T, Heeren J, Gieselmann V, Braulke T, Kollmann K (2015) Traffic 16:743-59 Abstract
    • Mannose 6-phosphate-independent Lysosomal Sorting of LIMP-2. Blanz J, Zunke F, Markmann S, Damme M, Braulke T, Saftig P, Schwake M (2015) Traffic 16:1127-36 Abstract
    • Increased osteoclastogenesis rather than missorting of lysosomal enzymes is causing bone loss in mucolipidosis II. Kollmann K, Pestka JM, Schöne E, Schweizer M, Karkmann K, Kühn SC, Catala-Lehnen P, Failla AV, Marshall RP, Krause M, Santer R, Amling M, Braulke T*, Schinke T* (2013) EMBO Mol Med 5:1871-1886 Abstract
    • Lysosomal dysfunction causes neurodegeneration in mucolipidosis II 'knock-in' mice. Kollmann K, Damme M, Markmann S, Morelle W, Schweizer M, Hermans-Borgmeyer I, Röchert AK, Pohl S, Lübke T, Michalski J-C, Käkelä R, Walkley SU, Braulke T* (2012) Brain 135:2661-2675 Abstract
    • A key enzyme in the biogenesis of lysosomes is a protease that regulates cholesterol metabolism. Marschner K, Kollmann K, Schweizer M, Braulke T*, Pohl S (2011) Science 333:87-90 Abstract
    • Mucolipidosis II is caused by mutations in GNPTA encoding the alpha/beta GlcNAc-1-phosphotransferase. Tiede S, Storch S, Lübke T, Henrissat B, Bargal R, Raas-Rothschild A, Braulke T* (2005) Nat Med 11:1109-1112 Abstract


    10/2017 - 09/2020
    German Research Foundation (DFG)
    Research Unit 2625:
    "Mechanisms of Lysosomal Homeostasis"
    www.for2625-lysosomes.de

    02/2016 - 01/2019
    Federal Ministry of Education and Research (BMBF)
    NCL2TREAT: A network for coordinated research and development of clinical biomarkers, diagnostics, pathomechanisms and therapeutic strategies for neuronal ceroid lipofuscinoses
    www.ncl2treat.de


    01/2016 - 12/2018
    EU Horizon 2020
    BATCure: European network for coordinated research on neuronal ceroid lipofuscinosis
    Website BATCure

    Logo SFB877


    07/2010 - 06/2018
    German Research Foundation (DFG)
    Collaborative Research Centre 877:
    "Proteolysis as a Regulatory Event in Pathophysiology"
    www.uni-kiel.de/Biochemie/sfb877/