title: MEF2D and MEF2C pathways disruption in sporadic and familial ALS patients.
abstract: Amyotrophic lateral sclerosis (ALS) is a progressive neuro-muscular disease characterized by motor neuron loss. MEF2D and MEF2C are members of the myocyte enhancer factor 2 family (MEF2), a group of transcription factors playing crucial roles both in muscle and in neural development and maintenance; for this reason, a possible involvement of MEF2 in ALS context has been investigated. Since the transcriptional activity of each tissue specific MEF2 isoform is conserved in different cell types, we chose to assess our parameters in an easily accessible and widely used experimental tool such as peripheral blood mononuclear cells (PBMCs) obtained from 30 sporadic ALS patients (sALS), 9 ALS patients with mutations in SOD1 gene (SOD1+) and 30 healthy controls. Gene expression analysis showed a significant up-regulation of MEF2D and MEF2C mRNA levels in both sporadic and SOD1+ ALS patients. Although protein levels were unchanged, a different pattern of distribution for MEF2D and MEF2C proteins was evidenced by immunohistochemistry in patients. A significant down-regulation of MEF2 downstream targets BDNF, KLF6 and RUFY3 was reported in both sALS and SOD1+ ALS patients, consistent with an altered MEF2 transcriptional activity. Furthermore, the potential regulatory effect of histone deacetylase 4 and 5 (HDAC4 and HDAC5) on MEF2D and MEF2C activity was also investigated. We found that MEF2D and HDAC4 colocalize in PBMC nuclei, while HDAC5 was localized in the cytoplasm. However, the unchanged HDACs localization and protein levels between sALS and controls seem to exclude their involvement in MEF2 altered function. In conclusion, our results show a systemic alteration of MEF2D and MEF2C pathways in both sporadic and SOD1+ ALS patients, underlying a possible common feature between the sporadic and the familial form of disease. Although further analyses in other neuromuscular diseases are needed to determine the specificity of changes in these pathways to ALS, measuring MEF2 alterations in accessible biofluids may be useful as biomarkers for disease diagnosis and progression.
authors.affiliation: School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, 20900 Monza, (MB), Italy; PhD program in Neuroscience, University of Milano-Bicocca, Italy. Electronic address: a.arosio10@campus.unimib.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Arosio
authors.affiliation: School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, 20900 Monza, (MB), Italy.
authors.forename: Gessica
authors.initials: G
authors.lastname: Sala
authors.affiliation: School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, 20900 Monza, (MB), Italy.
authors.forename: Virginia
authors.initials: V
authors.lastname: Rodriguez-Menendez
authors.affiliation: School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, 20900 Monza, (MB), Italy; PhD program in Neuroscience, University of Milano-Bicocca, Italy.
authors.forename: Denise
authors.initials: D
authors.lastname: Grana
authors.affiliation: NEuroMuscular Omnicentre (NEMO), Fondazione Serena Onlus, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Gerardi
authors.affiliation: NEuroMuscular Omnicentre (NEMO), Fondazione Serena Onlus, Milan, Italy.
authors.forename: Christian
authors.initials: C
authors.lastname: Lunetta
authors.affiliation: School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, 20900 Monza, (MB), Italy; Neurology Unit, San Gerardo Hospital, Monza, (MB), Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Ferrarese
authors.affiliation: School of Medicine and Surgery and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, 20900 Monza, (MB), Italy; Neurology Unit, San Gerardo Hospital, Monza, (MB), Italy.
authors.forename: Lucio
authors.initials: L
authors.lastname: Tremolizzo
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism; D003598:Cytoskeletal Proteins; D005260:Female; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D000075723:Kruppel-Like Factor 6 / Q000235:genetics / Q000378:metabolism; D064326:MEF2 Transcription Factors / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism; D009154:Mutation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000072105:Superoxide Dismutase-1 / Q000235:genetics; D015854:Up-Regulation; D020696:rab5 GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor; D003598:Cytoskeletal Proteins; C105465:KLF6 protein, human; D000075723:Kruppel-Like Factor 6; D064326:MEF2 Transcription Factors; C578040:MEF2C protein, human; C578043:MEF2D protein, human; D012333:RNA, Messenger; C550135:RUFY3 protein, human; C000606290:SOD1 protein, human; D000072105:Superoxide Dismutase-1; D006655:Histone Deacetylases; D020696:rab5 GTP-Binding Proteins
keywords: Amyotrophic lateral sclerosis; BDNF; HDAC4; HDAC5; KLF6; MEF2C; MEF2D; NPEPPS; RUFY3; SOD1