Project description:We report the single base pair analysis of the ocular transcriptome from wild type and BC027072 knockout animals. Comparison was analyzed to understand gene expression changes in a mouse model for early onset retinal degeneration which phenocopies a human form of autosomal recessive retinitis pigmentosa
Project description:We report the single base pair analysis of the ocular transcriptome from wild type and BC027072 knockout animals. Comparison was analyzed to understand gene expression changes in a mouse model for early onset retinal degeneration which phenocopies a human form of autosomal recessive retinitis pigmentosa Eye mRNA profiles were generated from 3 week-old C57BL/6J and BC027072 -/- in triplicate and sequenced using the Illumina HiSeq 2500
Project description:Retinal degeneration is the leading cause of irreversible blindness. Retinitis pigmentosa (RP) is a genetically heterogenous group of diseases. In the United States, approximately one in 4000 individuals is affected. RP begins with the loss of night vision due to the loss of rod photoreceptor cells. The disease progresses slowly with the loss of peripheral vision, and eventually leads to complete debilitating and irreversible blindness. The first mutation associated with human RP was identified in the gene encoding rhodopsin, the G-protein coupled receptor of rod photoreceptor cells. Mutations within the rhodopsin gene account for significant portion of RP cases. Specifically, mutations of the proline at residue 347 in rhodopsin have been linked to human RP.
Project description:To explore the mechanism associated with retinal degeneration and adeno-associated virus (AAV)-mediated gene therapy in rd10 mouse, a model of autosomal recessive retinitis pigmentosa (arRP) containing mutation of β subunit of the rod cGMP phosphodiesterase 6 (PDE6).
Project description:Recessive retinitis pigmentosa (RP) is often caused by nonsense mutations that lead to low mRNA levels as a result of nonsense-mediated decay. Some RP genes are expressed at detectable levels in leukocytes as well as in the retina. We designed a microarray-based method to find recessive RP genes based on low lymphoblast mRNA expression levels Keywords: Recessive mutations; mRNA expression; nonsense mediated-decay; retinitis pigmentosa; lymphocyte; Affymetrix genechip Human Genome U133Plus2.0.
Project description:As signalling organelles, primary cilia regulate their membrane G protein-coupled receptor (GPCR) content by ectocytosis, a process requiring localised actin dynamics at their tip to alter membrane shape.1,2 Mammalian photoreceptor outer segments comprise an expanse of folded membranes (discs) at the tip of highly-specialised connecting cilia (CC), in which photosensitive GPCRs like rhodopsin are concentrated. In an extraordinary feat of biology, outer segment discs are shed and remade daily.3 Defects in this process, due to genetic mutations, cause retinitis pigmentosa (RP), an untreatable, blinding disease. The mechanism by which photoreceptor cilia generate outer segments is therefore fundamental for vision yet poorly understood. Here, we show the membrane deformation required for outer segment disc genesis is driven by dynamic changes in the actin cytoskeleton in a process akin to ectocytosis. Further, we show RPGR, a leading causal RP gene, regulates activity of actin binding proteins crucial to this process. Disc genesis is compromised in Rpgr mouse models, slowing the actin dynamics required for timely disc formation, leading to aborted membrane shedding as ectosome-like vesicles, photoreceptor death and visual loss. Manipulation of actin dynamics partially rescues the phenotype, suggesting this pathway could be targeted therapeutically. These findings help define how actin-mediated dynamics control outer segment turnover.
Project description:Sex-specific attenuation of photoreceptor degeneration by reserpine in a rhodopsin P23H rat model of autosomal dominant retinitis pigmentosa
Project description:Neuronal plasticity of the inner retina has been observed in response to photoreceptor degeneration. Typically, this phenomenon has been considered maladaptive and may preclude vision restoration in the blind. However, several recent studies utilizing triggered photoreceptor ablation have shown adaptive responses in bipolar cell dendrites expected to support normal vision. Whether such homeostatic plasticity occurs during progressive photoreceptor degenerative disease to help maintain normal visual behavior is unknown. We addressed these issues in an established mouse model of Retinitis Pigmentosa caused by the P23H mutation in rhodopsin. We show robust modulation of the retinal transcriptomic network reminiscent of the neurodevelopmental state as well as potentiation of rod – rod bipolar cell signaling following rod photoreceptor degeneration. Additionally, we found highly sensitive night vision in P23H mice even when more than half of the rod photoreceptors were lost. The results implicate retinal adaptation leading to persistent visual function during photoreceptor degenerative disease.
