Project description:Gene expression analysis of retinas from a mouse model of the mild form of Zellweger spectrum disorder (ZSD). Mice homozygous for the hypomorphic Pex1-G844D allele, the murine ortholog of the human PEX1-G843D mutation found in a subset of patients with autosomal recessive ZSD, develop phenotypes found in humans with a milder form of ZSD, including retinal degeneration and vision loss. Similar to humans, mice heterozygous for the hypomorphic Pex1-G844D allele do not display age-related retinal abnormalities. We conducted a comparative analysis of retinal gene expression profile from Pex1-G844D homozygous and heterozygous mice in order to investigate the pathomechanisms of vision loss in humans with mild forms of ZSD. Whole retinas were obtained from 4 mice homozygous and 4 mice heterozygous for the hypomorphic Pex1-G844D allele, the murine ortholog of the human PEX1-G843D mutation found in a subset of patients with autosomal recessive Zellweger spectrum disorder (ZSD). The former group of animals show abnormal age-related related retinal degeneration due to peroxisome assembly defect resulting from having two copies of the hypomorphic Pex1-G844D allele. The latter group of animals display no evidence of abnormal age-related retinal degeneration due to the presence of one wild type copy of the Pex1 gene. The overall goal was to identify differentially expressed genes between mice homozygous and heterozygous for the hypomorphic Pex1-G844D allele that are informative of the pathomechanisms of age-related retinal degeneration in the former group.
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:The study was aimed at understanding the expression of known neutrophil regulating factors in the retinal pigment epithelium (RPE) cells with increasing age in a mouse model (Cryba1 cKO, mice lacking gene which codes for beta A3/A1-crystallin protein only in the RPE cells) of age-related macular degeneration
Project description:We report that decreased expression and activity of AhR exacerbates murine neovascular age-related macular degeneration, and increases cell migration and tube formation. The mechanism involves increased expression of pro-angiogenic mediators and altered matrix degradation. The results of our study suggest that the AhR signaling pathway may be important in multiple AMD related pathways. Gene expression analysis in the retinal pigment epithelium (RPE)-choroid tissue from AhR knockout mice contrasted against wild-type age-matched controls.
Project description:Illumina Infinium HumanMethylation450 BeadChip data from genomic DNA of retinal pigment epithelium from Age-related Macular Degeneration patients or age-matched controls.
Project description:To understand the age-related retinal gene changes, gene transcription profiles of neural retinal tissues from young adult (3-month) mice and old (20-month) mice were investigated by microarray. With age, 632 genes were up-regulated and 429 genes were down-regulated in the retina. Functional annotation showed that genes linked to immune responses and to tissue stress/injury responses were most modified by old age. Significant numbers of gene involved in the innate immune response including leukocyte activation, chemotaxis, endocytosis, complement activation, phagocytosis and myeloid cell differentiation were up-regulated and only a few were down-regulated. Increased microglial and complement activation in the aging retina was further confirmed by confocal microscopy of retinal tissues. The results suggest that retinal aging is accompanied with activation of a number of local inflammatory responses. A modified form of low-grade chronic inflammation (para-inflammation) characterizes these aging changes and involves mainly the innate immune system. Para-inflammation per se may be beneficial to normal retinal physiology in aging by promoting retinal homeostasis; conversely, dysreulation of the para-inflammation response may contribute to the pathogenesis of age-related retinal degeneration. Six young (3-month) and six old (20-month) mice were used for microarray study. Total RNA from each sample were extracted and undergone quality control analysis. RNA from 3 mice of the same group were then pooled together for gene array experiment.