L Winter1,2, A Unger3,4, C Berwanger5,6, M Spörrer7, M Türk8, F Chevessier1, K-H Strucksberg6, U Schlötzer-Schrehardt9, I Wittig10, W H Goldmann7, K Marcus11, W A Linke3,12, C S Clemen5,6, R Schröder1. 1. Institute of Neuropathology, University Hospital Erlangen, Erlangen, Germany. 2. Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria. 3. Department of Cardiovascular Physiology, Ruhr-University Bochum, Bochum, Germany. 4. Institute for Genetics of Heart Diseases, University Hospital Münster, Münster, Germany. 5. Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany. 6. Center for Biochemistry, Institute of Biochemistry I, Medical Faculty, University of Cologne, Cologne, Germany. 7. Center for Medical Physics and Technology, Biophysics Group, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany. 8. Department of Neurology, University Hospital Erlangen, Erlangen, Germany. 9. Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany. 10. Functional Proteomics, SFB815 Core Unit, Medical School, Goethe University, Frankfurt, Germany. 11. Medizinisches Proteom-Center, Medical Faculty, Ruhr-University Bochum, Bochum, Germany. 12. Institute of Physiology II, University of Münster, Münster, Germany.
Abstract
AIMS: We investigated newly generated immortalized heterozygous and homozygous R349P desmin knock-in myoblasts in conjunction with the corresponding desminopathy mice as models for desminopathies to analyse major protein quality control processes in response to the presence of R349P mutant desmin. METHODS: We used hetero- and homozygous R349P desmin knock-in mice for analyses and for crossbreeding with p53 knock-out mice to generate immortalized R349P desmin knock-in skeletal muscle myoblasts and myotubes. Skeletal muscle sections and cultured muscle cells were investigated by indirect immunofluorescence microscopy, proteasomal activity measurements and immunoblotting addressing autophagy rate, chaperone-assisted selective autophagy and heat shock protein levels. Muscle sections were further analysed by transmission and immunogold electron microscopy. RESULTS: We demonstrate that mutant desmin (i) increases proteasomal activity, (ii) stimulates macroautophagy, (iii) dysregulates the chaperone assisted selective autophagy and (iv) elevates the protein levels of αB-crystallin and Hsp27. Both αB-crystallin and Hsp27 as well as Hsp90 displayed translocation patterns from Z-discs as well as Z-I junctions, respectively, to the level of sarcomeric I-bands in dominant and recessive desminopathies. CONCLUSIONS: Our findings demonstrate that the presence of R349P mutant desmin causes a general imbalance in skeletal muscle protein homeostasis via aberrant activity of all major protein quality control systems. The augmented activity of these systems and the subcellular shift of essential heat shock proteins may deleteriously contribute to the previously observed increased turnover of desmin itself and desmin-binding partners, which triggers progressive dysfunction of the extrasarcomeric cytoskeleton and the myofibrillar apparatus in the course of the development of desminopathies.
AIMS: We investigated newly generated immortalized heterozygous and homozygous R349Pdesmin knock-in myoblasts in conjunction with the corresponding desminopathymice as models for desminopathies to analyse major protein quality control processes in response to the presence of R349P mutant desmin. METHODS: We used hetero- and homozygous R349Pdesmin knock-in mice for analyses and for crossbreeding with p53 knock-out mice to generate immortalized R349Pdesmin knock-in skeletal muscle myoblasts and myotubes. Skeletal muscle sections and cultured muscle cells were investigated by indirect immunofluorescence microscopy, proteasomal activity measurements and immunoblotting addressing autophagy rate, chaperone-assisted selective autophagy and heat shock protein levels. Muscle sections were further analysed by transmission and immunogold electron microscopy. RESULTS: We demonstrate that mutant desmin (i) increases proteasomal activity, (ii) stimulates macroautophagy, (iii) dysregulates the chaperone assisted selective autophagy and (iv) elevates the protein levels of αB-crystallin and Hsp27. Both αB-crystallin and Hsp27 as well as Hsp90 displayed translocation patterns from Z-discs as well as Z-I junctions, respectively, to the level of sarcomeric I-bands in dominant and recessive desminopathies. CONCLUSIONS: Our findings demonstrate that the presence of R349P mutant desmin causes a general imbalance in skeletal muscle protein homeostasis via aberrant activity of all major protein quality control systems. The augmented activity of these systems and the subcellular shift of essential heat shock proteins may deleteriously contribute to the previously observed increased turnover of desmin itself and desmin-binding partners, which triggers progressive dysfunction of the extrasarcomeric cytoskeleton and the myofibrillar apparatus in the course of the development of desminopathies.
Authors: Michael Haug; Charlotte Meyer; Barbara Reischl; Gerhard Prölß; Kristina Vetter; Julian Iberl; Stefanie Nübler; Sebastian Schürmann; Stefan J Rupitsch; Michael Heckel; Thorsten Pöschel; Lilli Winter; Harald Herrmann; Christoph S Clemen; Rolf Schröder; Oliver Friedrich Journal: Sci Rep Date: 2019-07-24 Impact factor: 4.379
Authors: Barbara Elsnicova; Daniela Hornikova; Veronika Tibenska; David Kolar; Tereza Tlapakova; Benjamin Schmid; Markus Mallek; Britta Eggers; Ursula Schlötzer-Schrehardt; Viktoriya Peeva; Carolin Berwanger; Bettina Eberhard; Hacer Durmuş; Dorothea Schultheis; Christian Holtzhausen; Karin Schork; Katrin Marcus; Jens Jordan; Thomas Lücke; Peter F M van der Ven; Rolf Schröder; Christoph S Clemen; Jitka M Zurmanova Journal: Int J Mol Sci Date: 2022-10-10 Impact factor: 6.208