title: Tau Accumulation, Altered Phosphorylation, and Missorting Promote Neurodegeneration in Glaucoma.
abstract: Glaucoma, the leading cause of irreversible blindness worldwide, is characterized by the selective death of retinal ganglion cells (RGCs). Ocular hypertension is the most significant known risk factor for developing the disease, but the mechanism by which elevated pressure damages RGCs is currently unknown. The axonal-enriched microtubule-associated protein tau is a key mediator of neurotoxicity in Alzheimer's disease and other tauopathies. Using a well characterized in vivo rat glaucoma model, we show an age-related increase in endogenous retinal tau that was markedly exacerbated by ocular hypertension. Early alterations in tau phosphorylation, characterized by epitope-dependent hyperphosphorylation and hypophosphorylation, correlated with the appearance of tau oligomers in glaucomatous retinas. Our data demonstrate the mislocalization of tau in the somatodendritic compartment of RGCs subjected to high intraocular pressure. In contrast, tau was depleted from RGC axons in the optic nerve of glaucomatous eyes. Importantly, intraocular administration of short interfering RNA against tau effectively reduced retinal tau accumulation and promoted robust survival of RGC somas and axons, supporting a critical role for tau alterations in ocular hypertension-induced neuronal damage. Our study reveals that glaucoma displays signature pathological features of tauopathies, including tau accumulation, altered phosphorylation, and missorting; and identifies tau as a novel target to counter RGC neurodegeneration in glaucoma and prevalent optic neuropathies.
  
  
  
  In this study, we investigated the role of tau in retinal ganglion cell (RGC) damage in glaucoma. We demonstrate that high intraocular pressure leads to a rapid increase in endogenous retinal tau with altered phosphorylation profile and the formation of tau oligomers. Tau accumulation was primarily observed in RGC dendrites, while tau in RGC axons within the optic nerve was depleted. Attenuation of endogenous retinal tau using a targeted siRNA led to striking protection of RGC somas and axons from hypertension-induced damage. Our study identifies novel and substantial alterations of endogenous tau protein in glaucoma, including abnormal subcellular distribution, an altered phosphorylation profile, and neurotoxicity.
authors.affiliation: Department of Neuroscience and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Université de Montréal, Montréal, Québec H2X 0A9, Canada.
authors.forename: Marius
authors.identifier: 0000-0001-7581-5843
authors.initials: M
authors.lastname: Chiasseu
authors.affiliation: Department of Neuroscience and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Université de Montréal, Montréal, Québec H2X 0A9, Canada.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Cueva Vargas
authors.affiliation: Department of Neuroscience and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Université de Montréal, Montréal, Québec H2X 0A9, Canada.
authors.forename: Laurie
authors.initials: L
authors.lastname: Destroismaisons
authors.affiliation: Department of Neuroscience and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Université de Montréal, Montréal, Québec H2X 0A9, Canada.
authors.forename: Christine
authors.initials: C
authors.lastname: Vande Velde
authors.affiliation: Department of Neuroscience and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Université de Montréal, Montréal, Québec H2X 0A9, Canada.
authors.forename: Nicole
authors.initials: N
authors.lastname: Leclerc
authors.affiliation: Department of Neuroscience and Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Université de Montréal, Montréal, Québec H2X 0A9, Canada adriana.di.polo@umontreal.ca.
authors.forename: Adriana
authors.identifier: 0000-0003-1430-0760
authors.initials: A
authors.lastname: Di Polo
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005901:Glaucoma / Q000378:metabolism* / Q000473:pathology; D007429:Intraocular Pressure; D008297:Male; D010766:Phosphorylation; D021381:Protein Transport; D051381:Rats; D012162:Retinal Degeneration / Q000378:metabolism* / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000378:metabolism* / Q000473:pathology*; D024801:Tauopathies / Q000378:metabolism* / Q000473:pathology; D016875:tau Proteins / Q000378:metabolism*
chemical_list: D016875:tau Proteins
keywords: Alzheimer's disease; axon degeneration; glaucoma; neurotoxicity; retinal ganglion cell; tau