Purchase this article with an account.
N. Piri, M. Song, J.M. K. Kwong, J. Caprioli; Expression of Crystallin Genes Is Downregulated in Experimental Glaucoma . Invest. Ophthalmol. Vis. Sci. 2006;47(13):1825.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To analyze expression changes of crystallin genes in glaucomatous retinas with the aim to identify genes associated with retinal ganglion cell (RGC) death.
A rat glaucoma model was generated with chronic, moderate elevation of the intraocular pressure (IOP). Gene expression profiles in glaucomatous retinas were analyzed with rat oligo microarray slides. Real–time quantitative PCR and immunoblot analysis were used to determine the changes in mRNA and protein levels of crystallin genes in control (n=6) and experimental retinas (n=6). In situ hybridization was carried out with digoxigenin–labeled RNA probes to localize the expression of crystallin genes in the retina.
Gene profiles of experimental glaucomatous retinas revealed that the expression of several members of the crystallin superfamily were downregulated after IOP elevation. The expression levels of αA, ßA1/A3, ßA2, ßA4, and ßB2 were decreased by two fold or more and the level of the αB transcript was reduced 1.6 times. Quantitative real–time PCR analysis of mRNA levels of cystallin genes confirmed their downregulation. At the protein levels, αA was approximately 2 and 1.6 fold lower in experimental retinas two– and five–weeks after IOP elevation, respectively, compared to controls. The level of αB in two– and five–week experimental retinas decreased by about 2.7 and 1.6 times, respectively. ßA1/A3 and ßB2 were downregulated 3.3 and 1.6 fold two weeks after IOP increase, respectively. In retinas exposed to elevated IOP for five weeks, the level of these proteins decreased by about twofold. ßA2– and bA4–crystallins were not detected at the protein level in retinal extract. Furthermore, we showed that in control retinas the expression of these crystallin genes is predominantly localized in the ganglion cell layer of the retina.
Downregulation of six members of the crystallin superfamily at the mRNA and protein levels suggests their involvement in glaucomatous damage to the retina. Since crystallins are known to have cell–protective function by increasing cell resistance to stress–inducible apoptosis, we believe that dowregulation of these genes in glaucomatous retinas could undermine cell survival properties and may therefore be associated with RGC death after IOP elevation.
This PDF is available to Subscribers Only