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Wahl, V.* ; Vogler, S.* ; Grosche, A.* ; Pannicke, T.* ; Ueffing, M. ; Wiedemann, P.* ; Reichenbach, A.* ; Hauck, S.M. ; Bringmann, A.*

Osteopontin inhibits osmotic swelling of retinal glial (Müller) cells by inducing release of VEGF.

Neuroscience 246, 59-72 (2013)
DOI PMC
Open Access Green as soon as Postprint is submitted to ZB.
Osmotic swelling of retinal neurons and glial cells is an important pathogenic factor of retinal edema formation. Here, we show that the neuroprotective factor osteopontin (OPN), which is released from retinal glial (Müller) cells after stimulation of the cells with glial cell line-derived neurotrophic factor (Del Río et al., 2011, Glia 59:821-832), inhibits the swelling of rat Müller cells induced by hypoosmotic exposure of retinal slices in the presence of barium ions and H2O2, respectively, and in slices of postischemic retinas. OPN did not inhibit the hypoosmotic swelling of bipolar cells in slices of control and postischemic retinas. The inhibitory effect of OPN on Müller cell swelling was dose-dependent, with a half-maximal effect at ∼0.6ng/ml. The effect of OPN was abrogated in the presence of pharmacological blockers of vascular endothelial growth factor (VEGF) receptor-2, metabotropic glutamate receptors, and purinergic receptors (P2Y1, adenosine A1 receptors), as well as of a neutralizing anti-VEGF antibody. The data suggest that OPN induces the release of VEGF, glutamate, ATP, and adenosine from Müller cells. The effect of OPN was also prevented by blockers of voltage-gated sodium channels (tetrodotoxin), T-type voltage-gated calcium channels (kurtoxin), potassium channels (clofilium), and chloride channels 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB). The swelling-inhibitory effect of OPN was dependent on intracellular calcium signaling, activation of phospholipase C and protein kinase C, and vesicular exocytosis of glutamate. In retinal slices, Müller glial cells display immunoreactivity of OPN. The data suggest that Müller cell-derived OPN has (in addition to the effects on photoreceptors and retinal neurons) autocrine effects. The neuroprotective effects of OPN may be in part mediated by the prevention of cytotoxic Müller cell swelling and the release of VEGF and adenosine from Müller cells.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Osteopontin ; Vegf ; Osmotic Swelling ; Ischemia ; Glia ; Retina; Endothelial Growth-factor ; Nitric-oxide Synthase ; Rat Retina ; Volume Regulation ; Glutamate Release ; Up-regulation ; Rds Degeneration ; Ganglion-cells ; Potential Role ; Macular Edema
ISSN (print) / ISBN 0306-4522
e-ISSN 1873-7544
Journal Neuroscience
Quellenangaben Volume: 246, Issue: , Pages: 59-72 Article Number: , Supplement: ,
Publisher International Brain Research Organization, Elsevier
Non-patent literature Publications
Reviewing status Peer reviewed