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  2. Ferroptosis induces detrimental effects in chronic EAE and its implications for progressive MS

Ferroptosis induces detrimental effects in chronic EAE and its implications for progressive MS

  • Acta Neuropathol Commun. 2023 Jul 25;11(1):121. doi: 10.1186/s40478-023-01617-7.
Priya Jhelum 1 Stephanie Zandee 2 3 Fari Ryan 1 Juan G Zarruk 1 Bernhard Michalke 4 Vivek Venkataramani 5 Laura Curran 1 Wendy Klement 2 3 Alexandre Prat 2 3 Samuel David 6
Affiliations

Affiliations

  • 1 Centre for Research in Neuroscience and BRaIN Program, Research Institute of the McGill University Health Centre (RI-MUHC), Livingston Hall, Room L7-210, 1650 Cedar Ave., Montreal, QC, H3G 1A4, Canada.
  • 2 Neuroimmunology Research Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada.
  • 3 Department of Neuroscience, Faculty of Medicine, Université de Montréal, Montreal, Canada.
  • 4 Research Unit Analytical BioGeoChemistry, Helmholz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
  • 5 Comprehensive Cancer Center Mainfranken, University Hospital Würzburg, 97080, Würzburg, Germany.
  • 6 Centre for Research in Neuroscience and BRaIN Program, Research Institute of the McGill University Health Centre (RI-MUHC), Livingston Hall, Room L7-210, 1650 Cedar Ave., Montreal, QC, H3G 1A4, Canada. sam.david@mcgill.ca.
Abstract

Ferroptosis is a form of lipid peroxidation-mediated cell death and damage triggered by excess iron and insufficiency in the glutathione antioxidant pathway. Oxidative stress is thought to play a crucial role in progressive forms of multiple sclerosis (MS) in which iron deposition occurs. In this study we assessed if Ferroptosis plays a role in a chronic form of experimental autoimmune encephalomyelitis (CH-EAE), a mouse model used to study MS. Changes were detected in the mRNA levels of several Ferroptosis genes in CH-EAE but not in relapsing-remitting EAE. At the protein level, expression of iron importers is increased in the earlier stages of CH-EAE (onset and peak). While expression of hemoxygenase-1, which mobilizes iron from heme, likely from phagocytosed material, is increased in macrophages at the peak and progressive stages. Excess iron in cells is stored safely in ferritin, which increases with disease progression. Harmful, redox active iron is released from ferritin when shuttled to autophagosomes by 'nuclear receptor coactivator 4' (NCOA4). NCOA4 expression increases at the peak and progressive stages of CH-EAE and accompanied by increase in redox active ferrous iron. These changes occur in parallel with reduction in the antioxidant pathway (system xCT, Glutathione Peroxidase 4 and glutathione), and accompanied by increased lipid peroxidation. Mice treated with a Ferroptosis inhibitor for 2 weeks starting at the peak of CH-EAE paralysis, show significant improvements in function and pathology. Autopsy samples of tissue sections of secondary progressive MS (SPMS) showed NCOA4 expression in macrophages and oligodendrocytes along the rim of mixed active/inactive lesions, where ferritin+ and iron containing cells are located. Cells expressing NCOA4 express less ferritin, suggesting ferritin degradation and release of redox active iron, as indicated by increased lipid peroxidation. These data suggest that Ferroptosis is likely to contribute to pathogenesis in CH-EAE and SPMS.

Keywords

Antioxidants; Experimental autoimmune encephalomyelitis; Iron toxicity; Lipid peroxidation; NCOA4; Secondary progressive MS.

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