Purchase this article with an account.
H. Yi, O. Mohamed, D. Dufort, A. Hackam; Activation Of The Wnt Signaling Pathway Protects Retinal Cultures From Oxidative Stress . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2048.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Understanding basic signaling mechanisms that contribute to photoreceptor survival will result in important insights into retina function and disease, and could lead to the development of novel neuroprotective therapies. The Wnt signaling pathway controls many critical cellular processes. Our research and others’ have suggested that Wnt signaling may be involved in photoreceptor degeneration, although its precise role in the disease process is unknown. To determine potential activities of the Wnt pathway in diseased retina we tested the effect of Wnt signaling on cultured retinas.
Retinas from post–natal (day 5 and 8) mice, transgenic for the LacZ gene controlled by a Wnt responsive promoter, were dissociated by gentle papain treatment and plated onto poly–D–lysine/laminin coated dishes in neurobasal growth media. After 6 days, the cultures were fixed in 4% paraformaldehyde for immunohistochemistry. Cell viability was measured by Wst–1 assay in the presence or absence of 1 mM hydrogen peroxide.
Immunodetection of rhodopsin and glutamine synthetase demonstrated that the cultures were enriched for rod photoreceptors and Muller glia, respectively. To induce oxidative stress the cultures were incubated with 1 mM hydrogen peroxide for 16 hr, which lead to a 45% reduction in viability (p<0.001). The cultures were then treated with the canonical Wnt signaling activator SB216763 prior to hydrogen peroxide incubation. SB216763 rescued the P5 and P8 cultures from oxidative stress, increasing the viability to 50% higher than DMSO controls (p<0.001) and up to the viability level of non–peroxide treated cultures.
The dissociated retina culture system allows us to rapidly assess neuroprotection activity of candidate cellular signaling pathways. Our study indicates that a Wnt signaling activator protects cultures from oxidative stress. Studies are ongoing to identify which cell types respond to Wnt activation and to determine whether Wnt signaling is protective in vivo.
This PDF is available to Subscribers Only