title: [Spreading of protein misfolding: A new paradigm in neurology].
abstract: Protein misfolding and spreading ("transconformation") are being better understood. Described in Prions diseases, this new paradigm in the field of neurodegenerative disorders and brain aging also implies sporadic inclusion myositis, type 2 diabetes, some cancers, sickle cell disease... Misfolding is transmitted from a protein or peptide to a normally folded one. Often associated with a stress of the endoplasmic reticulum, it may spread along the neurites, following anterograde or retrograde axonal transport. In the central nervous system, it occurs in a few cells and there is invasion of adjacent cells by cell-to-cell spread. Three varieties of protein misfolding occur along neuroanatomical pathways. It can be a 'centripetal' process. The synucleinopathy of Parkinson disease has been carefully studied: the changes first occur in cardiac or enteric plexuses... and reach later on the mesencephalon and neocortex. Thus, skin biopsy might prove a diagnostic tool. Protein misfolding may also occur along 'centrifugal' pathways, from motor cortex to peripheral motor neurons. Examples are provided by SOD and pTDP-43 in Amyotrophic Lateral Sclerosis. Amyloid β peptide in cerebral aging and Alzheimer's disease also spread from occipital cortex to the brainstem. Lastly, the propagation may remain 'central' for TDP-43 in behavioral variant frontotemporal dementia, following only pathways of the encephalic neural network. This has to be confirmed, however, since the spreading of some proteins (such as tau or Aβ peptides) has been considered central for a long time and has proved today to involve extracerebral tissues. The complex mechanisms of protein misfolding, still in analysis, include the involvement of chaperone proteins, the formation of very toxic labile proteins molecules (oligomers?), and provide a number of new therapeutic perspectives.
authors.affiliation: Biologie, Académie nationale de médecine, 16, rue Bonaparte, 75272 Paris cedex 06, France. Electronic address: j.hauw@academie-medecine.fr.
authors.forename: J-J
authors.initials: JJ
authors.lastname: Hauw
authors.affiliation: Centre de recherche de l'institut du cerveau et de la moelle épinière (CRICM), équipe « Maladie d'Alzheimer-maladie à prions », UPMC-Sorbonne universités, 75013 Paris, France; Centre de référence des ATNC, ICM, groupe hospitalier Pitié-Salpêtrière, 75013 Paris, France; Cellule nationale de référence des maladies de Creutzfeldt-Jakob, groupe hospitalier Pitié-Salpêtrière, AP-HP, 75013 Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Haïk
authors.affiliation: Centre de recherche de l'institut du cerveau et de la moelle épinière (CRICM), équipe « Maladie d'Alzheimer-maladie à prions », UPMC-Sorbonne universités, 75013 Paris, France; Laboratoire de neuropathologie Raymond-Escourolle, groupe hospitalier Pitié-Salpêtrière, AP-HP, 75013 Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Duyckaerts
mesh_terms: D006801:Humans; D009422:Nervous System Diseases / Q000209:etiology / Q000473:pathology*; D009462:Neurology; D057165:Proteostasis Deficiencies / Q000150:complications / Q000473:pathology*
keywords: Alzheimer; Maladies neurodégénératives; Neurodegenerative diseases; Parkinson; Prions; Protein misfolding; Transconformation