DNA methylation changes in glial cells of the normal-appearing white matter in Multiple Sclerosis patients Lara Kular1*, Ewoud Ewing1, Maria Needhamsen1, Majid Pahlevan Kakhki1, Ruxandra Covacu1, David Gomez-Cabrero2,3,4, Lou Brundin1,2 and Maja Jagodic1*. 1Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden. 2Department of Medicine, Unit of Computational Medicine, Center for Molecular Medicine, Karolinska Institutet, Solna, Sweden. 3Mucosal and Salivary Biology Division, King's College London Dental Institute, London, SE1 9RT, UK. 4Translational Bioinformatics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain. 5Department of Neurology, Karolinska University Hospital, Stockholm, Sweden. *To whom correspondence should be addressed: Maja Jagodic and Lara Kular, Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden,
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[email protected]. Abstract Background Multiple Sclerosis (MS), the leading cause of non-traumatic neurological disability in young adults, is a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS). Due to the poor accessibility to the target organ, CNS-confined processes underpinning the later progressive form of MS remain elusive thereby limiting treatment options. We aim to examine DNA methylation, a stable epigenetic mark of genome activity, in glial cells to capture relevant molecular changes underlying MS neuropathology. Methods We profiled DNA methylation in nuclei of glial cells, isolated from 38 post-mortem normal-appearing white matter (NAWM) specimens of MS patients (n=8) in comparison to white matter of control individuals (n=14), using Infinium MethylationEPIC BeadChip. Findings We identified 1,226 significant (genome-wide adjusted P-value < 0.05) differentially methylated positions (DMPs) between MS patients and controls.