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Rapamycin down‐regulates REDD1 to blunt cell death: a potential way to maintain retinal ganglion cell function as in glaucoma
Author(s) -
DEL OLMO AGUADO S,
NÚÑEZ ÄLVAREZ C,
OSBORNE NN
Publication year - 2014
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2014.f008.x
Subject(s) - retina , microbiology and biotechnology , retinal ganglion cell , viability assay , gene silencing , biology , pi3k/akt/mtor pathway , glaucoma , retinal , cell culture , signal transduction , genetics , neuroscience , gene , biochemistry
Purpose Determine whether REDD1 is present the retina and located to retinal ganglion cells (RGCs). Moreover, to deduce whether siRNA silencing of REDD1 synthesis and/or rapamycin counteract insults to cells in culture. Methods Western blot, quantitative PCR and immunohistochemistry were used to show the presence and localisation of REDD1 in the rat retina and RGC‐5 cells (a cell line derived from the retina). REDD1 was down‐regulated in RGC‐5 cells by gene silencing (siRNA) methodology. RGC‐5 cells where REDD1 was silenced or not were subjected to insults of either cobalt chloride (CoCl2) or blue light, for defined times. Results REDD1 is present in the rat retina. Moreover, REDD1‐immunoreactivity is located to different retinal cell‐types but intensely concentrated to a many but not all RGCs. REDD1 is also present in the cytoplasm of RGC‐5 cells and appears not to particularly locate in mitochondria. CoCl2 or blue light insults to RGC‐5 cells resulted in cell death and an up‐regulation of REDD1. Loss of cell viability was significantly nullified in RGC‐5 cells exposed to rapamycin or where REDD1 was silenced. Moreover, rapamycin was not toxic to RGC‐5 cells even at high concentrations. Conclusion Evidence is provided to suggest that rapamycin can down regulate REDD1, part of the mTOR complex receptor mechanism. It is concluded that REDD1, present in RGCs, is activated when insulted as in glaucoma and that this process can be attenuated by use of rapamycin.