Age-related reduction in retinal deimination levels in the F344BN rat.
Ontology highlight
ABSTRACT:
SUBMITTER: Bhattacharya SK
PROVIDER: S-EPMC2722784 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Deimination is a form of protein posttranslational modification carried out by the peptidyl arginine deiminases (PADs) enzymes. PAD2 is the principal deiminase expressed in the retina. Elevated levels of PAD2 and protein deimination are present in a number of human neurological diseases, with or without ocular manifestation. To define the association of deimination with the pathogenesis of age-related macular degeneration (AMD), we studied protein deimination and PAD2 levels in retinas of AMD donor eyes compared to age-matched non-AMD retinas. Eyes from non-AMD and AMD donors were fixed in 4% paraformaldehyde and 0.5% glutaraldehyde in phosphate buffer. Retina and retinal pigment epithelium (RPE) from donor eyes were processed for immunohistochemical detection and western blotting using antibodies to PAD2 and citrulline residues. The ganglion cell, inner plexiform, inner nuclear and outer nuclear layers were labeled by both PAD2 and citrulline antibodies. Changes in the localization of deiminated residues and PAD2 were evident as the retinal layers were remodeled coincident with photoreceptor degeneration in AMD retinas. Immunodetection of either PAD2 or citrulline residues could not be evaluated in the RPE layer due to the high autofluorescence levels in this layer. Interestingly, higher deimination immunoreactivity was detected in AMD retinal lysates. However, no significant changes in PAD2 were detected in the AMD and non-AMD retinas and RPE lysates. Our observations show increased levels of protein deimination but not PAD2 in AMD retinas and RPE, suggesting a reduced rate of turnover of deiminated proteins in these AMD retinas.
| S-EPMC3683981 | biostudies-literature
Project description:Old rats are resistant to fibrate-induced hypolipidemia owing to a reduction in hepatic peroxisome proliferator-activated receptor alpha (PPARalpha). We tested whether the age-related decrease in PPARalpha is prevented by atorvastatin (ATV), a hypolipidemic statin. We determined the activity and expression of Liver X receptor alpha (LXRalpha) and PPARalpha in the liver of 18-month-old rats treated with 10 mg kg(-1) of ATV for 21 days. We measured fatty acid oxidation (FAO), the expression of PPARalpha-target genes, liver triglyceride (TG) and cholesteryl ester (CE) contents and plasma concentrations of TG, cholesterol, glucose, nonesterified fatty acids (NEFA), insulin and leptin. While old female rats were practically unresponsive, ATV-treated old males showed lower liver TG (-41%) and CE (-48%), and plasma TG (-35%), glucose (-18%) and NEFA (-39%). Age-related alterations in LXRalpha expression and binding activity were reverted in ATV-treated old males. These changes were related to an increase in hepatic FAO (1.2-fold), and PPARalpha mRNA (2.2-fold), PPARalpha protein (1.6-fold), and PPARalpha-binding activity. Hepatic nuclear factor-4 (HNF-4) and chicken ovalbumin upstream-transcription factor-II participate in the transcriptional regulation of the PPARalpha gene, while peroxisome proliferator-activated receptor gamma coactivator 1 (PGC-1) behaves as a PPAR coactivator. Ageing reduced the hepatic content of HNF-4 (74%) and PGC-1 (77%) exclusively in male rats. ATV administration to old males enhanced the hepatic expression and binding activity (two-fold) of HNF-4. ATV-induced changes in hepatic HNF-4 and PPARalpha may be responsible for the improvement of the lipid metabolic phenotype produced by ATV administration to senescent male rats.
| S-EPMC1576214 | biostudies-literature
Project description:Progressive loss of visual function frequently accompanies demyelinating diseases such as multiple sclerosis (MS) and is hypothesized to be the result of damage to the axons and soma of neurons. Here, we show that dendritic impairment is also involved in these diseases. Deimination, a posttranslational modification, was reduced in the retinal ganglion cell layer of MS patients and in a transgenic mouse model of MS (ND4 mice). Reduced deimination accompanied a decrease in inner retinal function in ND4 mice, indicating loss of vision. Local restoration of deimination dramatically improved retinal function and elongation of neurites in isolated neurons. Further, neurite length was decreased by downregulation of deimination or siRNA knockdown of the export-binding protein REF, a primary target for deimination in these cells. REF localized to dendrites and bound selective mRNAs and translation machinery to promote protein synthesis. Thus, protein deimination and dendritic outgrowth play key roles in visual function and may be a general feature of demyelinating diseases.
| S-EPMC3561814 | biostudies-literature
Project description:The first goal of the study was to find the genes that explain the difference in progression of age-related retinal degeneration (ageRD) between the inbred strains C57BL/6J-c2J (B6a) and BALB/cByJ (C). The specific goal was to find the candidate genes that explain the chromosome 6 and chromosome 10 quantitative trait loci (QTL) found in a previous study. Genes differentially expressed in retina between both strains and that map to the QTL are candidate genes. By integrating different approaches: microarray study, knowledge-based candidate gene search and screening of genetic variants, we found 35 candidate genes for chromosome 6 QTL and 14 candidate genes for chromosome 10 QTL. Five genes for each QTL were selected for sequencing and qPCR analysis. One gene, Tnfaip3 was selected for phenotypic testing and was excluded as the quantitative trait gene for chr10 QTL. The second goal of the study was to find biological processes and pathways associated with ageRD by Gene Ontology analysis of the microarray data. We concentrated on GO terms overrepresented in either strain at 8 months; the age when there is a difference in the phenotype (outer nuclear layer thickness). The GO analysis revealed that transcripts associated with inflammation, mitochondrial envelope, DNA repairing and oxidative stress were increased in the ageRD sensitive C strain with age (8 months). In the ageRD resistant B6a strain transcripts associated with antioxidant response, regulation of blood vessel size and growth factor activity were increased with age. Transcripts associated with cell remodeling and lipid metabolism were increased in either strain with age. This study aims to identify gene expression differences in posterior eyecups between the strains C and B6a at 4 months and at 8 months. Twelve animals were used per strain and time point for a total of 48 mice. Total RNA for 3 animals (6 eyes) were pooled giving a total of 4 biological replicates per strain and time point. The 4-month C samples labeled with Cy5 were hybridized with the 4-month B6a samples labeled with Cy3 (4 biological replicates); the 8-month C samples labeled with Cy5 were hybridized with the 8-month B6a samples labeled with Cy3, for 8 arrays (4 biological replicates). A second set of eight arrays were used to analyzed the same RNA samples but with the dye orientation reversed, yielding a total of 16 arrays in the experiment. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc.
2010-05-12 | E-GEOD-18151 | biostudies-arrayexpress
Project description:The musculoskeletal system (muscle-tendon-bone) demonstrates numerous age-related changes, with modifications in tendons the least well studied, although increased predisposition to tendinopathy and rupture have been reported. In order to gain insights into the basis of age-associated increase in tendon injuries, we compared Achilles and tibialis anterior tendons and myotendinous junctions (MTJs) from 3- to 5- and 22- to 25-month-old rats for underlying structure and composition. Significant decreases were observed by qRT-PCR for collagen I, III, and V mRNA expression in tendons of old rats, but immunostaining detected no apparent differences in collagen I and V expression on the protein level. Tendons of old compared with young rats had decreased mRNA expression levels of proteoglycan 4 (PRG4) and elastin (Eln), but no differences in the mRNA expression of connective tissue growth factor, TGF-beta 1, or stromal cell-derived factor 1. For PRG4, immunostaining showed good correlation with qRT-PCR results. This is the first study to show reductions in PRG4 in tendons and MTJs of old rats. Decreased PRG4 expression in tendons could result in increased tendon stiffness and may be associated with decreased activity in the elderly. The diminished collagen mRNA expression in combination with decreased PRG4 and Eln mRNA expression may be associated with increased risk of tendon injury with aging.
| S-EPMC3824999 | biostudies-literature
Project description:The first goal of the study was to find the genes that explain the difference in progression of age-related retinal degeneration (ageRD) between the inbred strains C57BL/6J-c2J (B6a) and BALB/cByJ (C). The specific goal was to find the candidate genes that explain the chromosome 6 and chromosome 10 quantitative trait loci (QTL) found in a previous study. Genes differentially expressed in retina between both strains and that map to the QTL are candidate genes. By integrating different approaches: microarray study, knowledge-based candidate gene search and screening of genetic variants, we found 35 candidate genes for chromosome 6 QTL and 14 candidate genes for chromosome 10 QTL. Five genes for each QTL were selected for sequencing and qPCR analysis. One gene, Tnfaip3 was selected for phenotypic testing and was excluded as the quantitative trait gene for chr10 QTL. The second goal of the study was to find biological processes and pathways associated with ageRD by Gene Ontology analysis of the microarray data. We concentrated on GO terms overrepresented in either strain at 8 months; the age when there is a difference in the phenotype (outer nuclear layer thickness). The GO analysis revealed that transcripts associated with inflammation, mitochondrial envelope, DNA repairing and oxidative stress were increased in the ageRD sensitive C strain with age (8 months). In the ageRD resistant B6a strain transcripts associated with antioxidant response, regulation of blood vessel size and growth factor activity were increased with age. Transcripts associated with cell remodeling and lipid metabolism were increased in either strain with age. This study aims to identify gene expression differences in posterior eyecups between the strains C and B6a at 4 months and at 8 months. Twelve animals were used per strain and time point for a total of 48 mice. Total RNA for 3 animals (6 eyes) were pooled giving a total of 4 biological replicates per strain and time point. The 4-month C samples labeled with Cy5 were hybridized with the 4-month B6a samples labeled with Cy3 (4 biological replicates); the 8-month C samples labeled with Cy5 were hybridized with the 8-month B6a samples labeled with Cy3, for 8 arrays (4 biological replicates). A second set of eight arrays were used to analyzed the same RNA samples but with the dye orientation reversed, yielding a total of 16 arrays in the experiment.
2010-05-12 | GSE18151 | GEO
Project description:In order to evaluate the gene expression profile of retinal microglia cells in different age, we purified CD11b-positive microglia from the retinas of wild type C57BL/6 mice at 3, 12, 18, and 24 months age using cell sorting method with flow cytometry. Age-related genes from isolated retinal microglia were performed using 16 Affymetrix GeneChips of Mouse Exon 1.0ST Arrays. Gene expression level between consecutive age groups (i.e. between 3 and 12 months, 12 and 18 months, and 18 and 24 months) was examined to identify microglia relevant aging genes that demonstrated significant changes. We identified a total 719 genes that showed increasing or decreasing more than 1.5-fold change (p<0.05, one-way ANOVA) for at least one of the three inter age-group comparisons. These identified genes were subjected to a hierarchical cluster analysis to visualize trends in differential expression across individual biological repeats in the 4 age groups. The microglia cells were isolated from wild type C57BL/6 mice with microglia cell specific marker CD11b conjugated with FITC using flowcytometry sorting. The aging time point was designed as 4 groups: 3 moth, 12 month, 18 month and 24 month; each group includes 4 repeats. The total RNA was extracted from isolated retinal microglia cells and reverse transcripted to cDNA after amplification and labeling. The gene expression profile was detected with Affymetrix GeneChip of Mouse Exon 1.0ST Arrays
2012-12-01 | E-GEOD-38739 | biostudies-arrayexpress
Project description:PurposeBlood vessels of the retina provide an easily-accessible, representative window into the condition of microvasculature. We investigated how retinal vessel structure captured in fundus photographs changes with age, and how this may reflect features related to patient health, including blood pressure.ResultsWe used two approaches. In the first approach, we segmented the retinal vasculature from fundus photographs and then we correlated 25 parameterized aspects ("traits")-comprising 15 measures of tortuosity, 7 fractal ranges of self-similarity, and 3 measures of junction numbers-with participant age and blood pressure. In the second approach, we examined entire fundus photographs with a set of algorithmic CHARM features. We studied 2,280 Sardinians, ages 20-28, and an U.S. based population from the AREDS study in 1,178 participants, ages 59-84. Three traits (relating to tortuosity, vessel bifurcation number, and vessel endpoint number) showed significant changes with age in both cohorts, and one additional trait (relating to fractal number) showed a correlation in the Sardinian cohort only. When using second approach, we found significant correlations of particular CHARM features with age and blood pressure, which were stronger than those detected when using parameterized traits, reflecting a greater signal from the entire photographs than was captured in the segmented microvasculature.ConclusionsThese findings demonstrate that automated quantitative image analysis of fundus images can reveal general measures of patient health status.
| S-EPMC6497255 | biostudies-literature
Project description:PurposeComplex two-dimensional (2D) patterns of hyperfluorescent short-wave fundus autofluorescence (FAF) at the border of geographic atrophy (GA) can predict its expansion in patients with late non-exudative "dry" AMD. However, preclinical models do not phenocopy this important feature of disease. We sought to describe the spatiotemporal changes in hyperfluorescent FAF patterns that occur following acute oxidative stress, potentially in association with GA expansion.MethodsSprague Dawley rats (n = 54) received systemic sodium iodate (25-45 mg/kg, n = 90 eyes) or saline (n = 18 eyes) and underwent serial full fundus imaging by confocal scanning laser ophthalmoscopy, including blue FAF and delayed near-infrared analysis. Composite images of the fundus were assembled, and the 2D patterns were described qualitatively and quantitatively. A subset of eyes underwent tissue analysis, and four underwent optical coherence tomography (OCT) imaging.ResultsReproducibly changing, complex patterns of hyperfluorescent FAF emerge at the borders of toxin-induced damage; however, in the absence of GA expansion, they percolate inward within the region of retinal pigment epithelium loss, evolving, maturing, and senescing in situ over time. Unexpectedly, the late FAF patterns most closely resemble the diffuse tricking form of clinical disease. A five-stage classification system is presented.ConclusionsLongitudinal, full-fundus imaging of outer retinal atrophy in the rat eye identifies evolving, complex patterns of hyperfluorescent FAF that phenocopy aspects of disease.Translational relevanceThis work provides a novel tool to assess hyperfluorescent FAF in association with progressive retinal atrophy, a therapeutic target in late AMD.
| S-EPMC8914569 | biostudies-literature
Project description:microRNAs (miRNAs) are small noncoding RNAs that post-transcriptionally regulate gene expression by targeting specific mRNAs. Altered expression of circulating miRNAs have been associated with age-related diseases including cancer and cardiovascular disease. Although we and others have found an age-dependent decrease in miRNA expression in peripheral blood mononuclear cells (PBMCs), little is known about the role of circulating miRNAs in human aging. Here, we examined miRNA expression in human serum from young (mean age 30 years) and old (mean age 64 years) individuals using next generation sequencing technology and real-time quantitative PCR. Of the miRNAs that we found to be present in serum, three were significantly decreased in 20 older individuals compared to 20 younger individuals: miR-151a-5p, miR-181a-5p and miR-1248. Consistent with our data in humans, these miRNAs are also present at lower levels in the serum of elderly rhesus monkeys. In humans, miR-1248 was found to regulate the expression of mRNAs involved in inflammatory pathways and miR-181a was found to correlate negatively with the pro-inflammatory cytokines IL-6 and TNFa and to correlate positively with the anti-inflammatory cytokines TGFb and IL-10. These results suggest that circulating miRNAs may be a biological marker of aging and could also be important for regulating longevity. Identification of stable miRNA biomarkers in serum could have great potential as a noninvasive diagnostic tool as well as enhance our understanding of physiological changes that occur with age. Examination of microRNAs isolated from human serum from 11 young (mean age 30 yrs) and 11 old (mean age 64 yrs) individuals and from peripheral blood mononuclear cells from one young (30 yr) and one old (64 yr) individual.
2013-12-18 | E-GEOD-53439 | biostudies-arrayexpress