Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Changes in gene expression in the retina of diabetic Long Evans rats after one, four, and twelve weeks of diabetes

ABSTRACT: Purpose. Patients with diabetic retinopathy may experience severe vision loss due to macular edema and neovascularization secondary to vascular abnormalities. However, before these abnormalities become apparent, there are functional deficits in contrast sensitivity, color perception, and dark adaptation. The goals of this study are to evaluate early changes (up to 3 months) in retinal gene expression, selected visual cycle proteins, and optokinetic tracking (OKT) in streptozotocin (STZ)-induced diabetic rats.Methods. Retinal gene expression in diabetic Long Evans rats was measured by whole genome microarray 7 days, 4 weeks, and three months after onset of hyperglycemia. Select gene and protein changes were probed by PCR and immunohistochemistry respectively, and OKT thresholds were measured using a virtual optokinetics system. Results. Microarray analysis showed that the most consistently affected molecular and cellular functions were cell-to-cell signaling and interaction, cell death, cellular growth and proliferation, molecular transport, and cellular movement. Further analysis revealed reduced expression of several genes encoding visual cycle proteins including lecithin:retinol acyltransferase (LRAT), retinal pigment epithelium (RPE)-specific protein 65kDa (RPE65) and RPE retinal G protein coupled receptor (RGR). Immunohistochemistry revealed a decrease in RPE65 in the RPE layer of diabetic rats. These molecular changes occurred simultaneously with a decrease in OKT thresholds by 4 weeks of diabetes. Conclusions. The data presented here are further evidence that inner retinal cells are affected by hyperglycemia prior to vasculopathy suggesting that glial and neuronal dysfunction may underlie some of the early visual deficits in diabetics. At each of the three timepoints (day 7, day 28, and day 84) one retina each from three diabetic rats were pooled for analysis on a single microarray chip. Three independent experiments were conducted for each group (n=9 animals/group). Each timepoint contained a hyperglycemic (STZ) and a control (buffer injection only) group. Additionally, on day 7 gene changes in the retina of rats which received a single injection of STZ, but did not develop hyperglycemia (STZ-non-c) were analyzed.

ORGANISM(S): Rattus norvegicus

SUBMITTER: Stefanie Kirwin

PROVIDER: E-GEOD-28831 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Retinal gene expression and visually evoked behavior in diabetic long evans rats.

Kirwin Stefanie J SJ Kanaly Suzanne T ST Hansen Candice R CR Cairns Belinda J BJ Ren Meina M Edelman Jeffrey L JL

Investigative ophthalmology & visual science 20110929 10

<h4>Purpose</h4>Patients with diabetic retinopathy may experience severe vision loss due to macular edema and neovascularization secondary to vascular abnormalities. However, before these abnormalities become apparent, there are functional deficits in contrast sensitivity, color perception, and dark adaptation. The goals of this study are to evaluate early changes (up to 3 months) in retinal gene expression, selected visual cycle proteins, and optokinetic tracking (OKT) in streptozotocin (STZ)-i ...[more]

PMID: 21862641

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Project description:Patients with long-duration diabetes develop cardiovascular complications resulting in highly increased mortality and complications which affect the kidneys, eyes and peripheral nerves associated with high morbidity. Among the diabetic complications, damage in the eye, diabetic retinopathy, is the most common microvascular complication of diabetes. Diabetic retinopathy is a leading cause of vision-loss globally. It is characterized by a number of different patho-mechanisms including changes in vascular permeability, capillary degeneration, and finally at a late stage overshooting formation of new blood vessels. This expression analysis focused on the use of different experimental models for Diabetes Mellitus and its complications (for a review see 1: Al-Awar et al: Experimental Diabetes Mellitus in Different Animal Models. J Diabetes Res. 2016; doi: 10.1155/2016/9051426). By that, we wanted to uncover the relative contributions of systemic hyperinsulinaemia and/or hyperglycemia to molecular regulations. The following models have been used: As insulinopenic, hyperglycemic model reflecting Type 1 diabetes, male STZ-Wistar rats (60mg/kg BW; i.p.) were used. Wistar rats without STZ injection served as non-diabetic controls. Male obese ZDF rats (Fa/Fa) were used as type-2 diabetes model characterized by persisting hyperglycemia and transient hyperinsulinemia. Male lean ZDF rats (Fa/-) served as non-diabetic controls. Male obese ZF rats (Fa/Fa) hyperglycemia were used reflecting euglycemia and severe insulin resistance. Male lean ZF rats (Fa/-) served as controls. ZDF and ZF rats were obtained in two genotypes, obese (genotype fa/fa) and lean littermates (genotype Fa/?). All rats were housed in standard cages under a normal light-dark cycle for 16 weeks. All animals had free access to food and water. ZF and Wistar rats received a standard chow (Ssniff R/M) and ZDF rats received Purina 5008 chow. A group size of n=8 were used for all study groups. Wistar rats were rendered type-1 like hyperglycemic and hypoinsulinemic via a single injection of streptocotocin (STZ, 60mg/kg; i.p.) at 7 weeks of age. Obese ZDF rats (fa/fa) develop spontaneously a type-2 diabetes phenotype with persisting hyperglycemia and transient hyperinsulinemia (hyperglycemic, hypoinsulinemic). Obese ZF rats (fa/fa) develop insulin resistance with permanent hyperinsulinemia without concomitant hyperglycemia and no overt diabetes phenotype. Non STZ treated Wistar rats, lean ZDF littermates (Fa/?), and lean ZF littermates (Fa/?) served as controls. All groups were kept for 12 weeks on respective conditions together with appropriate age-matched controls. Unbiased gene expression analysis was performed per group using Affymetrix gene arrays.

Project description:OBJECTIVE: To study the genetic regulatory mechanisms in the remote zone of left ventricular (LV) free wall in order to partly explain the more frequent progression to heart failure after acute myocardial infarction (AMI) in diabetic rats. METHODS: 10 weeks after diabetes mellitus (DM) induction with Streptozotocin (STZ), the left anterior descending coronary arteries of uncontrolled diabetic Sprague-Dawley (SD) rats and non-diabetic ones were ligated without reperfusion. Then, the remote zone tissues of LV free wall were taken as samples at day 1, 7, 14, 28, and 56 post AMI. Significant different expression genes were filterd from Affymetrix Genechip U230 2.0 array by GCOS software. Genetic changes post myocardial infarction were classified by hierarchical clustering of 10 gene chips. And then, the differential expressions of 10 selected transcripts identified by the microarray were examined in greater detail by Real Time-PCR. RESULTS: According to hierarchical clustering, we find that the molecular regulatory expression related to cardiac remodeling in the remote zone to myocardial infarction is quite different as time elapses in both diabetic and non-diabetic rats. The gene expression at day 1 and 7 post AMI in both groups is similar, while the genetic changes at day 14 post AMI in diabetic rats and the ones at day 14 and 28 in non-diabetic rats are classified into the same cluster. And then the genetic changes at day 28 and 56 post AMI in diabetic rats and the ones at day 56 in non-diabetic rats are classified into the same cluster. (Figure.1) The patterns of numerous products of genes expression were used in the cluster, including 118 genes, such as leucine-rich PPR-motif containing (IL-6 signaling pathway), procollagen type I, VI, VIII, and XV, fibronectin1, RT1, and TIMP-1, etc. CONCLUSION: The genetic findings in this study might be the possible mechanism that diabetes mellitus can accerate the progression of post-infarction genetic regulatory expression. Experiment Overall Design: All studies were performed with male SD rats (200-220g), aged 8 weeks, which were obtained from laboratorial animal center of Chinese University of Agriculture. DM was induced with a singleintraperitoneal injection of STZ (65 mg/kg in 0.1mmol/L, pH 4.5 sodium citrate buffer) . Age and body weight matched rats that used as non-diabetic controls were injected with the same dose of sodium citrate buffer (0.1mmol/L, pH 4.5). Ultrastructure changes of myocardium were observed 10 weeks after DM induction by TEM. 10 weeks after DM induction,both diabetic and non-diabetic rats were subjected to left anterior descending coronary artery (LADCA) ischemia for 1-56 days without reperfusion. Two-dimensional echocardiography was utilized to obtain LV dimensions and LV percent fractional shortening at baseline, DM 10weeks, and at 1d, 7d, 14d, 28d, 56d after AMI; the remote zone tissues of LV free wall were taken as samples at day 1, 7, 14, 28, and 56 post AMI for gene chip microarray analysis (10 samples from 30 rats); in addition, heart-to-body weight and heart to tibial length ratios and masson's trichrome staining was measured as an index of cardiac hypertrophy and fibrosis at baseline, DM 10weeks, and at 1d, 7d, 14d, 28d, 56d after AMI.

Project description:There has been an incresing body of epidemiologic and biochemical evidence implying the role of cerebral insulin resistance in Alzheimer-type dementia. For a better understanding of the insulin effect on the central nervous system we performed microarray-based gene expression profiling in the hippocampus, striatum and prefrontal cortex of streptozotocin-induced and spontaneously diabetic Goto-Kakizaki rats as model animals for type 1 and type 2 diabetes, respectively. Following pathway analysis and validation of gene lists by RT-PCR, 30 genes from hippocampus, such as the inhibitory neuropeptide galanin, synuclein gamma and uncoupling protein 2, and 22 genes from the prefrontal cortex, e.g. galanin receptor 2, protein kinase gamma and epsilon, ABCA1, CD47 and the RET protooncogene, were found to exhibit altered expression levels in type 2 diabetic model animals in comparison to non-diabetic control animals. These gene lists proved to be partly overlapping and encompassed genes related to neurotransmission, lipidmetabolism, neuronal development, insulin secretion, oxidative damage and DNA repair. On the other hand, no significant alterations were found in the transcriptomes of the corpus sriatum in the same animals. Changes in the cerebral gene expression profiles seemed to be specific for the type 2 diabetic model, as no such alterations were found in streptozotocin-treated animals. According to our knowledge this is the first characterization of the whole-genome expression changes of specific brain regions in a diabetic model. Our findings shed light on the complex role of insulin signaling in fine-tuning brain functions, and provide further experimental evidence in support of the recently elaborated theory of type 3diabetes. Experiments were performed with 9 animals from each group. Wistar rats (control), streptoztocin-treated Wistar rats (type 1 diabetes) and Goto-Kakizaki rats (type 2 diabetes). The brain was removed and the striatum, hippocampus and prefrontal cortex were dissected. Samples from 3-3 identically treated animals were pooled. That means, 3 biological parallels were prepared from each brain region of type 1 or type 2 diabetic and control animals, amounting to a total of 27 different pooled samples.

Dataset Information

Changes in gene expression in the retina of diabetic Long Evans rats after one, four, and twelve weeks of diabetes

Publications

Retinal gene expression and visually evoked behavior in diabetic long evans rats.

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