Project description:Expression of the Endothelin-2 (Edn2) mRNA is greatly increased in the photoreceptors (PRs) of mouse models of inherited PR degeneration. To identify retinasl gene whose expression is directly or indirectly regulated by EDN2 in the presence of the Tg(RHO P347S) mutant allele, we defined mRNAs that were differentially expressed in Edn2+/+, Edn2-/-, Tg(RHO P347S) Edn2+/+, and Tg(RHO P347S) Edn2-/- retinas. RNA was extracted from Edn2+/+, Edn2-/-, Tg(RHO P347S) Edn2+/+, and Tg(RHO P347S) Edn2-/- retinas at postnatal day 21 (PN21) and hybridized to Affymetrix arrays
Project description:Expression of the Endothelin-2 (Edn2) mRNA is greatly increased in the photoreceptors (PRs) of mouse models of inherited PR degeneration. To identify retinasl gene whose expression is directly or indirectly regulated by EDN2 in the presence of the Tg(RHO P347S) mutant allele, we defined mRNAs that were differentially expressed in Edn2+/+, Edn2-/-, Tg(RHO P347S) Edn2+/+, and Tg(RHO P347S) Edn2-/- retinas.
Project description:Rhodopsin (RHO) mutations such as Pro23His, are the leading cause of dominantly inherited retinitis pigmentosa in North America. As with other dominant retinal dystrophies, these mutations lead to production of a toxic protein product, and treatment will require knockdown of the mutant allele. The purpose of this study was to develop a CRISPR-Cas9-mediated transcriptional repression strategy using catalytically inactive S. aureus Cas9 (dCas9) fused to the Krüppel-associated box (KRAB) transcriptional repressor domain. Using a reporter construct carrying GFP cloned downstream of the RHO promoter fragment (nucleotides -1403 to +73), we demonstrate a ~74%-84% reduction in RHO promoter activity in RHOpCRISPRi treated vs plasmid only controls. Following subretinal transduction of human retinal explants and transgenic Pro23His mutant pigs, significant knockdown of rhodopsin protein was achieved. Suppression of mutant transgene in vivo was associated with a reduction in ER-stress and apoptosis markers and preservation of photoreceptor cell layer thickness.
Project description:Rhodopsin is essential for phototransduction, and many rhodopsin mutations cause heritable retinal degenerations. The P23H rhodopsin variant generates a misfolded rhodopsin protein that photoreceptors quickly target for degradation by mechanisms that are incompletely understood. To gain insight into how P23H rhodopsin is removed from rods, we used mass spectrometry to identify protein interaction partners of P23H rhodopsin immunopurified from RhoP23H/P23H mice and to compare with protein interaction partners of wild-type rhodopsin from Rho+/+ mice. We identified 286 proteins associated with P23H rhodopsin and 276 proteins associated with wild-type rhodopsin. Only 113 proteins were shared between wild-type and mutant rhodopsin protein interactomes. In the P23H rhodopsin protein interactome, we saw loss of phototransduction, retinal cycle, and rhodopsin protein trafficking proteins but gain of ubiquitin-related proteins when compared with the wild-type rhodopsin protein interactome. In the P23H rhodopsin protein interactome, we saw significant enrichment of gene ontology terms related to ER-associated protein degradation, ER stress, and translation. Protein-protein interaction network analysis revealed that translational and ribosomal quality control proteins were the most significant regulators in the P23H rhodopsin protein interactome. The protein partners identified in our study may provide new insights into how photoreceptors recognize and clear mutant rhodopsin and may offer novel targets involved in retinal degeneration pathogenesis.
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. We are fortunate to have access to the P347S rhodopsin mutant mice. These mice represent an excellent transgenic mouse model of retinal degeneration. The P347S rhodopsin mutation is one of the best studied mutations, yet the mechanism by which the mutation causes degeneration is still unknown. One study has demonstrated that galectin-1 plays a role in degeneration of neuronal processes (1) and another study has shown that expression level of galectin-3 is elevated in retinas of patients with age-related macular degeneration. These studies in conjunction with the availibility of the P347S mutant mice have provided impetus to examine the pathogenesis of retinal degeneration in the context of the possible role of glycans and glycan-binding proteins. The time course of photoreceptor degeneration in the P347S mouse model has been carefully studied. In these mice, degeneration is barely detectable at 1 month of age, yet biochemical evidence suggests that the rod photoreceptor cells have already begun to die. At 4 months of age, approximately half of the rod photoreceptor cells have degenerated. To distinguish involvement of glycogens at the various stages of retinal degeneration, we have collected retinas of wild type and the mutant mice at four time points (1, 2, 3, and 4 months of age). This will allow us to identify the genes that target early, mid- and late stages of the retinal degeneration process. Thus we request the analysis of total 24 samples as specified below: Age Group (months) Mice No of samples at each time point 1 Wild type 3 2 Wild type 3 3 Wild type 3 4 Wild type 3 1 P347S 3 2 P347S 3 3 P347S 3 4 P347S 3 Total 24.
Project description:For isolation of rod, cone, and pineal photoreceptor cells, we used the transgenic zebrafish lines, Tg(rho:egfp)ja2Tg, Tg(gnat2:egfp)ja23Tg, and Tg(exorh:EGFP)ja1Tg, which express EGFP in rods, all cone subtypes, and pineal rod cells, respectively. Retinas were dissected from dark-adapted adult fish under dim red light. The isolated retinas were digested with trypsin in Ca2+-free Ringer’s solution. The reaction was terminated by adding soybean trypsin inhibitor and fetal bovine serum. The dissociated EGFP-positive cells were isolated with a fluorescence activating cell sorter (FACSAria, BD Biosciences) by the following three parameters: forward scatter, side scatter and green fluorescence. Goal was to determine differentially expressed genes among three types of photoreceptor cells.
Project description:Transcriptome profile of retinas from wild-type (c57BL/6) and RHO-P347S mice following AAV-mediated subretinal delivery of pre-miR-204 to study the molecular changes underlying the neuroprotective effect of miR-204 OE in mouse models of Inherited Retinal Disease (IRD) To determine the molecular changes associated with AAV-mediated delivery of miR-204 in the subretinal space of wild-type and IRD mouse models, we performed RNASeq analysis of retinas from c57BL/6 and RHO-P347S mice injected with the AAV2/8.CMV.miR204 and AAV2/8.CMV.miR204MUT vector in a paired manner.
Project description:P23H is the most common mutation in the RHODOPSIN (RHO) gene leading to a dominant form of retinitis pigmentosa (RP), a rod photoreceptor degeneration that invariably causes vision loss. Specific disruption of the disease P23H RHO mutant while preserving the wild-type (WT) functional allele would be an invaluable therapy for this disease. However, various technologies tested in the past failed to achieve effective changes and consequently therapeutic benefits. We validated a CRISPR/Cas9 strategy to specifically inactivate the P23H RHO mutant, while preserving the WT allele in vitro. We, then, translated this approach in vivo by delivering the CRISPR/Cas9 components in murine Rho+/P23H mutant retinae. Targeted retinae presented a high rate of cleavage in the P23H but not WT Rho allele. This gene manipulation was sufficient to slow photoreceptor degeneration and improve retinal functions. To improve the translational potential of our approach, we tested intravitreal delivery of this system by means of adeno-associated viruses (AAVs). To this purpose, the employment of the AAV9-PHP.B resulted the most effective in disrupting the P23H Rho mutant. Finally, this approach was translated successfully in human cells engineered with the homozygous P23H RHO gene mutation. Overall, this is a significant proof-of-concept that gene allele specific targeting by CRISPR/Cas9 technology is specific and efficient and represents an unprecedented tool for treating RP and more broadly dominant genetic human disorders affecting the eye, as well as other tissues.
Project description:The transcriptomes of Δrho mutant cells and of wild-type cells grown in RPMI medium with or without 40 or 80 µg/ml of BCM were analyzed using Agilent microarrays in order to analyze the effects of the Rho inhibitor bicyclomycin (BCM) treatment on antisense transcription and changes in the expression of protein coding genes. All antisense RNAs exhibiting higher levels in the rho mutant compared to the wild-type showed similar levels in BCM-treated wild-type cells (80 µg/ml BCM). In addition, microarray data revealed activation of the SaeR regulon in the presence of BCM as observed in the rho mutant.