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Abstract #27891 Published in IGR 13-1
Myelination transition zone astrocytes are constitutively phagocytic and have synuclein dependent reactivity in glaucoma
Nguyen JV; Soto I; Kim K-Y; Bushong EA; Oglesby E; Valiente-Soriano FJ; Yang Z; Davis C-HO; Bedont JL; Son JLProceedings of the National Academy of Sciences of the United States of America 2011; 108: 1176-1181
See also comment(s) by Adriana DiPolo •
Optic nerve head (ONH) astrocytes have been proposed to play both protective and deleterious roles in glaucoma. We now show that, within the postlaminar ONH myelination transition zone (MTZ), there are astrocytes that normally express Mac-2 (also known as Lgals3 or galectin-3), a gene typically expressed only in phagocytic cells. Surprisingly, even in healthy mice, MTZ and other ONH astrocytes constitutive internalize large axonal evulsions that contain whole organelles. In mouse glaucoma models, MTZ astrocytes further upregulate Mac-2 expression. During glaucomatous degeneration, there are dystrophic processes in the retina and optic nerve, including the MTZ, which contain protease resistant (gamma)-synuclein. The increased Mac-2 expression by MTZ astrocytes during glaucoma likely depends on this (gamma)-synuclein, as mice lacking (gamma)-synuclein fail to up-regulate Mac-2 at the MTZ after elevation of intraocular pressure. These results suggest the possibility that a newly discovered normal degradative pathway foraxonsmight contribute toglaucomatous neurodegeneration.
N. Marsh-Armstrong. Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States. marsh-armstrong@kennedykrieger.org
Classification:
11.8 Neuroprotection (Part of: 11 Medical treatment)
3.9 Pathophysiology (Part of: 3 Laboratory methods)
2.15 Optic nerve (Part of: 2 Anatomical structures in glaucoma)