@article {663, title = {Calpain-5 Expression in the Retina Localizes to Photoreceptor Synapses.}, journal = {Invest Ophthalmol Vis Sci}, volume = {57}, year = {2016}, month = {2016 05 01}, pages = {2509-21}, abstract = {

PURPOSE: We characterize calpain-5 (CAPN5) expression in retinal and neuronal subcellular compartments.

METHODS: CAPN5 gene variants were classified using the exome variant server, and RNA-sequencing was used to compare expression of CAPN5 mRNA in the mouse and human retina and in retinoblastoma cells. Expression of CAPN5 protein was ascertained in humans and mice in silico, in mouse retina by immunohistochemistry, and in neuronal cancer cell lines and fractionated central nervous system tissue extracts by Western analysis with eight antibodies targeting different CAPN5 regions.

RESULTS: Most CAPN5 genetic variation occurs outside its protease core; and searches of cancer and epilepsy/autism genetic databases found no variants similar to hyperactivating retinal disease alleles. The mouse retina expressed one transcript for CAPN5 plus those of nine other calpains, similar to the human retina. In Y79 retinoblastoma cells, the level of CAPN5 transcript was very low. Immunohistochemistry detected CAPN5 expression in the inner and outer nuclear layers and at synapses in the outer plexiform layer. Western analysis of fractionated retinal extracts confirmed CAPN5 synapse localization. Western blots of fractionated brain neuronal extracts revealed distinct subcellular patterns and the potential presence of autoproteolytic CAPN5 domains.

CONCLUSIONS: CAPN5 is moderately expressed in the retina and, despite higher expression in other tissues, hyperactive disease mutants of CAPN5 only manifest as eye disease. At the cellular level, CAPN5 is expressed in several different functional compartments. CAPN5 localization at the photoreceptor synapse and with mitochondria explains the neural circuitry phenotype in human CAPN5 disease alleles.

}, keywords = {Animals, Blotting, Western, Calpain, Cattle, Female, Gene Expression Regulation, Neoplastic, Humans, Immunohistochemistry, Male, Mice, Neoplasms, Experimental, Photoreceptor Cells, Retina, Retinal Neoplasms, Retinoblastoma, RNA, Neoplasm, Synapses, Tumor Cells, Cultured}, issn = {1552-5783}, doi = {10.1167/iovs.15-18680}, author = {Schaefer, Kellie A and Toral, Marcus A and Velez, Gabriel and Cox, Allison J and Baker, Sheila A and Borcherding, Nicholas C and Colgan, Diana F and Bondada, Vimala and Mashburn, Charles B and Yu, Chen-Guang and Geddes, James W and Tsang, Stephen H and Bassuk, Alexander G and Mahajan, Vinit B} } @article {641, title = {Reprogramming towards anabolism impedes degeneration in a preclinical model of retinitis pigmentosa.}, journal = {Hum Mol Genet}, volume = {25}, year = {2016}, month = {2016 10 01}, pages = {4244-4255}, abstract = {

Retinitis pigmentosa (RP) is an incurable neurodegenerative condition featuring photoreceptor death that leads to blindness. Currently, there is no approved therapeutic for photoreceptor degenerative conditions like RP and atrophic age-related macular degeneration (AMD). Although there are promising results in human gene therapy, RP is a genetically diverse disorder, such that gene-specific therapies would be practical in a small fraction of patients with RP. Here, we explore a non-gene-specific strategy that entails reprogramming photoreceptors towards anabolism by upregulating the mechanistic target of rapamycin (mTOR) pathway. We conditionally ablated the tuberous sclerosis complex 1 (Tsc1) gene, an mTOR inhibitor, in the rods of the Pde6bpreclinical RP mouse model and observed, functionally and morphologically, an improvement in the survival of rods and cones at early and late disease stages. These results elucidate the ability of reprogramming the metabolome to slow photoreceptor degeneration. This strategy may also be applicable to a wider range of neurodegenerative diseases, as enhancement of nutrient uptake is not gene-specific and is implicated in multiple pathologies. Enhancing anabolism promoted neuronal survival and function and could potentially benefit a number of photoreceptor and other degenerative conditions.

}, keywords = {Animals, Cell Death, Cellular Reprogramming, Cone-Rod Dystrophies, Disease Models, Animal, Humans, Macular Degeneration, Metabolism, Mice, Photoreceptor Cells, Retinal Cone Photoreceptor Cells, Retinal Rod Photoreceptor Cells, Retinitis Pigmentosa, TOR Serine-Threonine Kinases, Tumor Suppressor Proteins}, issn = {1460-2083}, doi = {10.1093/hmg/ddw256}, author = {Zhang, Lijuan and Justus, Sally and Xu, Yu and Pluchenik, Tamara and Hsu, Chun-Wei and Yang, Jin and Duong, Jimmy K and Lin, Chyuan-Sheng and Jia, Yading and Bassuk, Alexander G and Mahajan, Vinit B and Tsang, Stephen H} }