Filamin C myopathy: from pathogenic mutations towards novel targeted treatment concepts

• Applicants: Professor Dr. Dieter O. Fürst; Professor Dr. Rudolf Andre Kley
• Subject Area: Molecular and Cellular Neurology and Neuropathology
• Term: from 2009 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 101925924

• Final Report Year: 2017

Final Report Abstract

Myofibrillar myopathies (MFM) are a genetically and clinically heterogeneous group of inherited muscle disorders characterized by focal disintegration of myofibrils predominantly at myofibrillar Z-discs and by sarcoplasmic protein aggregation. Filamin C (FLNc)-related myopathies delineate diseases caused by mutations in the FLNC gene, including a subtype of MFM (filaminopathy). A main aim of our project was to decipher the composition of protein aggregates in MFM to get new insight into pathomechanisms by using proteomic analyses of laser-microdissected aggregates. Our network allowed us to analyze more than 100 samples from patients with mutations in known MFM genes and from MFM patients with unknown mutation. In this cohort >2600 proteins were identified and >300 of these were over-represented in aggregate areas. These are involved in protein degradation and quality control, protein processing in the ER and actin cytoskeleton regulation. We obtained important new insight in proteins and pathways contributing to the pathomechanisms of protein aggregation in MFM. A group of abundant aggregate proteins was over-represented in all or the majority of aggregate samples, allowing to define a proteomic “basic pattern” in MFM. Proteins of this group are involved in mechanical stabilization and repair of Z-discs. Protein aggregates composition in MFM differed from other protein aggregate myopathies (PAM), emphasizing the value of proteomic analyses in differential diagnosis of PAM. We also detected significant differences between proteomic profiles in different MFM subtypes and identified specific diagnostic biomarkers. As a rule, the proportion of the disease-causing protein was usually higher in aggregate samples of the related disease than in other MFM subtypes. Furthermore, we were even able to identify pathogenic mutations at the protein level, illustrating that proteomic analysis may enable direct identification of causative gene mutations in unresolved MFM patients without extensive genetic searches. Another prime goal of this project was to get deeper insight into the functional relevance of the multiple interactions of FLNc. Here we have identified new ligands and further characterized previously documented interactions. Measurement of FLNc dynamics revealed surprisingly high mobility with a half-life of seconds, rather than minutes if compared to -actinin. Importantly, the precise dynamic behaviour is modulated both by protein interactions and phosphorylation. Myopodin was identified as an adapter protein between FLNc and the ubiquitin-proteasome system and lysosomal degradation via its interactions with the co-chaperone BAG3 and the phagophore assembly factor VPS18. This machinery seems to be activated by stretch-induced partial unfolding of FLNc, mainly at its unique immunoglobulin (Ig)-like domain 20. We assume that this pathway is of great functional importance for filaminopathy induced by mutations causing aggregation of the resulting protein. Focal disruptions of the myofibrillar apparatus (termed "lesions") were identified as a result of eccentric exercise. These lesions, containing FLNc and its interacting proteins Xin and aciculin, are distinct from the classical protein aggregates described for MFM, and are more prevalent both in patient muscle biopsies and in our newly generated patient-mimicking knock-in mouse model of the human diseasecausing FLNC mutation (p.W2710X). This pathology suggests that FLNc regulates the mechanical stability of the myofibrillar Z-disc, resulting in the case of mutant FLNc in muscle weakness. We hypothesize that these lesions define pre-clinical stages of the disease, preceding the formation of protein aggregates. Cell lines generated from these animals will be of enormous value for future drugtesting approaches.

Publications

• DNA sequencing errors in molecular diagnostics of filamin myopathy. Clin Chem Lab Med 2010; 48:1409-1414
  Odgerel Z, van der Ven PFM, Fürst DO, Goldfarb LG
  
• Dominant-negative effects of a novel mutation in the filamin myopathy. Neurology 2010; 75:2137-2138
  Van der Ven PFM, Odgerel Z, Fürst DO, Goldfarb LG, Kono S, Miyajima H
  
• Distal myopathy with upper limb predominance caused by filamin C haploinsufficiency. Neurology 2011; 77:2105-2114
  Guergueltcheva V, Peeters K, Baets J, Ceuterick-de Groote C, Martin JJ, Suls A, De Vriendt E, Mihaylova V, Chamova T, Almeida-Souza L, Ydens E, Tzekov C, Hadjidekov G, Gospodinova M, Storm K, Reyniers E, Bichev S, van der Ven PFM, Fürst DO, Mitev V, Lochmüller H, Timmerman V, Tournev I, De Jonghe P, Jordanova A
  
• Mutations in the N-terminal actin-binding domain of filamin C cause a distal myopathy. Am J Hum Genet 2011; 88:729-740
  Duff RM, Tay V, Hackman P, Ravenscroft G, McLean C, Kennedy P, Steinbach A, Schöffler W, van der Ven PFM, Fürst DO, Song J, Djinović-Carugo K, Penttilä S, Raheem O, Reardon K, Malandrini A, Gambelli S, Villanova M, Nowak KJ, Williams DR, Landers JE, Brown RH Jr, Udd B, Laing NG
  
• Pathophysiology of protein aggregation and extended phenotyping in filaminopathy. Brain 2012 ;135:2642-2660
  Kley RA, Serdaroglu-Oflazer P, Leber Y, Odgerel Z, van der Ven PFM, Olivé, M Ferrer I, Onipe A, Mihaylov M, Bilbao JM, Lee HS, Höhfeld J, Djinović-Carugo K, Kong K, Tegenthoff M, Peters SA, Stenzel W, Vorgerd M, Goldfarb LG, Fürst DO
  
• Pathophysiology of protein aggregation and extended phenotyping in filaminopathy. Brain. 2012; 135:2642-2660
  Kley RA, Serdaroglu-Oflazer P, Leber Y, Odgerel Z, van der Ven PFM, Olivé M, Ferrer I, Onipe A, Mihaylov M, Bilbao JM, Lee HS, Höhfeld J, Djinovic-Carugo K, Kong K, Tegenthoff M, Peters SA, Stenzel W, Vorgerd M, Goldfarb LG, Fürst DO
  
• A combined laser microdissection and mass spectrometry approach reveals new disease relevant proteins accumulating in aggregates of filaminopathy patients. Mol Cell Proteomics 2013; 12:215-227
  Kley RA, Maerkens A, Leber Y, Theis V, Schreiner A, van der Ven PFM, Uszkoreit J, Stephan C, Eulitz S, Euler N, Kirschner J, Müller K, Meyer HE, Tegenthoff M, Fürst DO, Vorgerd M, Müller T, Marcus K
  
• Cellular mechanotransduction relies on tension-induced and chaperone-assisted autophagy. Curr Biol 2013; 23:430-435
  Ulbricht A, Eppler FJ, Tapia VE, van der Ven PF, Hampe N, Hersch N, Vakeel P, Stadel D, Haas A, Saftig P, Behrends C, Fürst DO, Volkmer R, Hoffmann B, Kolanus W, Höhfeld J
  
• Differential proteomic analysis of abnormal intramyoplasmic aggregates in desminopathy. J Proteomics 2013; 90:14-27
  Maerkens A, Kley RA, Olivé M, Theis V, van der Ven PFM, Reimann J, Milting H, Schreiner A, Uszkoreit J, Eisenacher M, Barkovits K, Güttsches AK, Tonillo J, Kuhlmann K, Meyer HE, Schröder R, Tegenthoff M, Fürst DO, Müller T, Goldfarb LG, Vorgerd M, Marcus K
  
• Identification of Xin-repeat proteins as novel ligands of the SH3 domains of nebulin and nebulette and analysis of their interaction during myofibril formation and remodeling. Mol Biol Cell 2013; 24:3215-3226
  Eulitz S, Sauer F, Pelissier M-C, Boisguerin P, Molt S, Schuld J, Orfanos Z, Kley RA, Volkmer R, Wilmanns M, Kirfel G, van der Ven PFM, Fürst DO
  
• In vivo characterization of human myofibrillar myopathy genes in zebrafish. Biochem Biophys Res Comm 2015; 461:217-223
  Bührdel JB, Hirth S, Kessler M, Westphal S, Forster M, Manta L, Wiche G, Schoser B, Schessl J, Schröder R, Clemen CS, Eichinger L, Fürst DO, van der Ven PFM, Rottbauer W, Just S
  
• Myofibrillar instability exacerbated by acute exercise in filaminopathy. Hum Mol Genet 2015; 24: 7207-7220
  Chevessier F, Schuld J, Orfanos Z, Plank AC, Wolf L, Maerkens A, Unger A, Schlötzer-Schrehardt U, Kley RA, Von Hörsten S, Marcus K, Linke WA, Vorgerd M, van der Ven PFM, Fürst DO, Schröder R
  
• New insights into the protein aggregation pathology in myotilinopathy by combined proteomic and immunolocalization analyses. Acta Neuropathol Commun 2015; 4:8
  Maerkens A, Olivé M, Schreiner A, Feldkirchner S, Schessl J, Uszkoreit J, Barkovits K, Güttsches AK, Theis V, Eisenacher M, Tegenthoff M, Goldfarb LG, Schröder R, Schoser B, van der Ven PFM, Fürst DO, Vorgerd M, Marcus K, Kley RA
  
• Breaking sarcomeres by in vitro exercise. Sci Rep 2016; 6:19614
  Orfanos Z, Gödderz MP, Soroka E, Gödderz T, Rumyantseva A, van der Ven PFM, Hawke TJ, Fürst DO
  
• Filamin C is a highly dynamic protein associated with fast repair of myofibrillar microdamage. Hum Mol Genet 2016; 25:2776-2788
  Leber Y, Ruparelia AA, Kirfel G, van der Ven PFM, Hoffmann B, Merkel R, Bryson-Richardson RJ, Fürst DO
  
• Mutant desmin substantially perturbs mitochondrial morphology, function and maintenance in skeletal muscle tissue. Acta Neuropathol 2016; 132:453-473
  Winter L, Wittig I, Peeva V, Eggers B, Heidler J, Chevessier F, Kley RA, Barkovits K, Strecker V, Berwanger C, Herrmann H, Marcus K, Kornblum C, Kunz WS, Schröder R, Clemen CS
  
• Proteomics of rimmed vacuoles define new risk allele in inclusion body myositis. Ann Neurol 2017; 81:227-239
  Güttsches AK, Brady S, Krause K, Maerkens A, Uszkoreit J, Eisenacher M, Schreiner A, Galozzi S, Mertens-Rill J, Tegenthoff M, Holton JL, Harms MB, Lloyd TE, Vorgerd M, Weihl CC, Marcus M, Kley RA