Purchase this article with an account.
Stefanie M. Hauck, Patricia del Río, Blanca Arango-Gonzales, Martin Irmler, Udo Bartsch, Elena Vecino, Marius Ueffing; GDNF-induced Osteopontin Secretion from Müller Glial Cells Promotes Photoreceptor Survival in the Pde6brd1 Mouse Model of Retinal Degeneration. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5445.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Glial cell line-derived neurotrophic factor (GDNF) enhances the survival of a variety of neurons, including photoreceptors (PR) in the retina. In contrast to most other GDNF receptive neurons, GDNF does, however, not exert its neuroprotective activity directly on PR neurons but transmits it indirectly by inducing expression of yet unknown neurotrophic factors in retinal Müller glial cells (RMG). The purpose of this study was the identification and validation of novel RMG-derived neurotrophic factors induced by GDNF.
Genome-wide transcriptome analysis was performed with Ilumina bead arrays on isolated retinas from mice treated with GDNF and compared to untreated controls. Differentially expressed candidates were screened for presence of secretion signals and expression of selected candidates was studied in situ with immunohistochemistry. Further, the potential neurotrophic function was validated on isolated primary photoreceptors as well as on short-term and long-term retinal explant cultures from Pde6brd1 mouse retinas.
Differential transcriptome analyses of GDNF-treated mouse retinas revealed 30 GDNF-induced transcripts containing a total of 6 genes coding for secreted molecules. Among them was Osteopontin (OPN), a secreted glycoprotein which was confirmed to be expressed in mouse RMG in situ and is secreted from primary mouse RMG in culture. OPN secretion was significantly upregulated upon GDNF treatment of primary mouse RMG. Furthermore, OPN exerted a significant survival effect on primary porcine PR cells and induced activation of the PI3K/Akt pro-survival pathway. In short term retinal explant cultures from Pde6brd1 mice, OPN significantly reduced the percentage of apoptotic cells to levels comparable to that observed in explants from wild-type mice and after long-term treatment, significantly more PR were present in the ONL of these retinas.
Our findings suggest that RMG-derived OPN transmits part of the GDNF-induced neuroprotective activity from RMG to PR cells. Furthermore, OPN qualifies as effective neuroprotective molecule for PR in the context of mutation-induced retinal degeneration.
This PDF is available to Subscribers Only