GENERATION AND CHARACTERIZATION OF HUMAN INDUCED PLURIPOTENT STEM CELLS FROM NEUROPATHOLOGICALLY CONFIRMED MULTIPLE SYSTEM ATROPHY PATIENT-DERIVED FIBROBLASTS

MIREIA ALEMANY-RIBES¹ALEXANDRA PEREZ-SORIANO²ALMUDENA SANTOS-BAJO¹ADRIA DANGLA-VALLS¹JACQUELINE SEVERINO¹MARTIN GIGIREY-SUAREZ¹DORY COHEN³MANEL FERNÁNDEZ-SÁNCHEZ⁴MARIO EZQUERRA²Maria Jose Marti²Veerle BAEKELANDT⁵WOUTER PEELAERTS⁵RONALD Melki³Yaroslau - Compta^2*LAURA BATLLE-MORERA^1*

• ¹Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
• ²Institut d'Investigacions Biomediques August Pi i Sunyer, Barcelona, Spain
• ³Centre National de la Recherche Scientifique, Paris, France
• ⁴Universitat de Barcelona, Barcelona, Spain
• ⁵Katholieke Universiteit Leuven, Leuven, Belgium

Background: Multiple system atrophy (MSA) is an adult-onset, fatal neurodegenerative disease, classified as a synucleinopathy along with Parkinson's disease and dementia with Lewy bodies. The etiology of MSA is unknown and the treatment remains symptomatic with limited efficacy. To date most studies have been conducted on genetic mice models, engineered to overexpress α-synuclein (aSyn); and transmission mice models, treated with intracerebral injections of MSA brain extracts or fibrillar aSyn which can be assembled de novo or using MSA seeds. An in vitro human model is urgently needed to identify the human-specific and even patient-specific molecular mechanisms underlying the disease. Method: For this purpose, we report the generation of six fully characterized induced pluripotent stem cells (iPSCs) lines, which were reprogrammed from disease-derived skin fibroblasts and represent the two major clinical MSA variants with either predominant parkinsonism (MSA-P) or cerebellar dysfunction (MSA-C). Five of these cases received postmortem neuropathological confirmation of definite MSA diagnosis. Results: The generated iPSC clones meet the International Society for Stem Cell Research (ISSCR) quality standards for genomic stability and functional pluripotency to ensure experimental reproducibility. None of the clones acquired genetic abnormalities after the reprogramming and the extended culture passage, as evaluated by G-banded karyotyping and digital PCR targeting recurrent iPSC copy number variant hotspots. All the clones expressed pluripotent markers as NANOG, LIN28A and SSEA4 and differentiated efficiently into each of the three embryonic germ layers. Furthermore, we assessed their potential for disease modeling by generating oligodendrocytes (OLs), since the pathologic hallmark of MSA is the aberrant accumulation of aSyn within OLs cytoplasm. We obtained both O4+ oligodendrocyte progenitor cells and MBP+ mature oligodendrocyte cells. Conclusion: We have created a robust and valuable iPSC collection aimed at correlating the in vivo confirmed clinical and pathological variants with the in vitro phenotypes. This unique tool can contribute to the understanding of MSA pathophysiology, the discovery of therapeutic targets, and the development of therapeutic screening approaches.