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The retinal proteome in experimental diabetic retinopathy: up-regulation of crystallins and reversal by systemic and periocular insulin.

ABSTRACT: Diabetic retinopathy is the leading cause of blindness in working age persons. Targeted studies have uncovered several components of the pathophysiology of the disease without unveiling the basic mechanisms. This study describes the use of complementary proteomic and genomic discovery methods that revealed that the proteins of the crystallin superfamily are increased dramatically in early diabetic retinopathy. Orthogonal methods confirmed that the amplitude of the up-regulation is greater than other changes described so far in diabetic retinopathy. A detailed time course study during diabetes showed differential up-regulation of the different isoforms of the crystallins superfamily. alpha- and beta-crystallins were regulated primarily at the translation level, whereas gamma-crystallins were also regulated transcriptionally. We also demonstrated cell-specific patterns of expression of the different crystallins in normal and diabetic rat retinas. In addition, systemic and periocular insulin treatments restored retinal crystallin protein expression during diabetes, indicating effects of phosphoinositide 3-kinase/Akt activity. Altogether this work shows the importance of proteomics discovery methods coupled with targeted approaches to unveil new disease mechanistic details and therapeutic targets.

SUBMITTER: Fort PE

PROVIDER: S-EPMC2667355 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature

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The retinal proteome in experimental diabetic retinopathy: up-regulation of crystallins and reversal by systemic and periocular insulin.

Fort Patrice E PE Freeman Willard M WM Losiewicz Mandy K MK Singh Ravi S J RS Gardner Thomas W TW

Molecular & cellular proteomics : MCP 20081201 4

Diabetic retinopathy is the leading cause of blindness in working age persons. Targeted studies have uncovered several components of the pathophysiology of the disease without unveiling the basic mechanisms. This study describes the use of complementary proteomic and genomic discovery methods that revealed that the proteins of the crystallin superfamily are increased dramatically in early diabetic retinopathy. Orthogonal methods confirmed that the amplitude of the up-regulation is greater than o ...[more]

PMID: 19049959

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Project description:BACKGROUND:Diabetes can lead to serious microvascular complications such as proliferative diabetic retinopathy (PDR), which results in severe vision loss. The diabetes-induced alterations in the vitreous protein composition in diabetic patients with PDR may be responsible for the presence of PDR. The vitreous humour can be utilised in a variety of studies aimed toward the discovery of new targets for the treatment or prevention of PDR and the identification of novel disease mechanisms. The aim of this study was to compare the protein profile of vitreous humour from diabetic patients with PDR with that of vitreous humour from normal human eyes donated for corneal transplant. RESULTS:Vitreous humour from type 2 diabetic patients with PDR (n = 10) and from normal human eyes donated for corneal transplant (n = 10) were studied. The comparative proteomic analysis was performed using two-dimensional fluorescence difference gel electrophoresis (2-D DIGE). Differentially produced proteins (abundance ratio > 2 or < -2, p < 0.01) were identified by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and MALDI-TOF tandem mass spectrometry. A total of 1242 protein spots were detected on the 2-D master gel of the samples, and 57 spots that exhibited statistically significant variations were successfully identified. The spots corresponded to peptide fragments of 29 proteins, including 8 proteins that increased and 21 proteins that decreased in PDR. Excluding the serum proteins from minor vitreous haemorrhage, 19 proteins were found to be differentially produced in PDR patients compared with normal subjects; 6 of these proteins have never been reported to be differentially expressed in PDR vitreous: N(G),N(G)-dimethylarginine dimethylaminohydrolase 1 (DDAH 1), tubulin alpha-1B chain, gamma-enolase, cytosolic acyl coenzyme A thioester hydrolase, malate dehydrogenase and phosphatidylethanolamine-binding protein 1 (PEBP 1). The differential production of pigment epithelium-derived factor (PEDF) and clusterin was confirmed by Western blot analysis. CONCLUSIONS:These data provide an in-depth analysis of the human vitreous proteome and reveal protein alterations that are possibly involved in the pathogenesis of PDR. Further investigation of these special proteins may provide potential new targets for the treatment or the prevention of PDR.

Project description:ObjectivesTo determine the risk factors for retinal microvascular impairment on optical coherence tomography angiography (OCT-A) in type 2 diabetic patients without clinical diabetic retinopathy (DR).MethodsThis retrospective and cross-sectional study enrolled 74 diabetic patients without clinically evident DR for the study group and 34 healthy subjects for the control group. OCT-A parameters were measured to determine vascular density (VD) and the foveal avascular zone (FAZ) size in the superficial and deep capillary plexuses (SCP/DCP) of the retina. Clinical data were collected on sex, age, diabetes duration, hemoglobin A1c (HbA1c), hypertension, dyslipidemia, low-density lipoprotein cholesterol (LDL-C), estimated glomerular filtration rate (eGFR) and smoking status. Multiple linear regression analyses were performed to represent the associated clinical variables with OCT-A parameters in diabetic patients.ResultsIn comparison between the study and control groups, the VD in the SCP and DCP were significantly lower in diabetic patients compared to the controls (P = 0.022 and 0.003, respectively). The FAZ size in the SCP and DCP were significantly greater in diabetic patients compared to the controls (P = 0.035 and <0.001, respectively). In age- and sex-adjusted multiple regression analyses for the diabetic patients, dyslipidemia and hypertension were negatively associated with SCP-VD (β = -0.357, P = 0.002; β = -0.239, P = 0.039, respectively). Current smoking was correlated with lower DCP-VD (β = -0.255, P = 0.043). Greater SCP-FAZ size was associated with dyslipidemia and greater LDL-C (β = 0.254, P = 0.013; β = 0.232, P = 0.029, respectively), and greater DCP-FAZ size, with lower eGFR and greater LDL-C (β = -0.355, P = 0.004; β = 0.235, P = 0.037, respectively).ConclusionsDiabetic patients without clinical DR showed lower VD and greater FAZ size in the SCP and DCP compared to healthy controls. In diabetic patients without clinical DR, dyslipidemia and/or high LDL-C were important risk factors for retinal microvascular impairment. Hypertension, current smoking and lower eGFR also contributed to microvascular impairment.

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.

Dataset Information

The retinal proteome in experimental diabetic retinopathy: up-regulation of crystallins and reversal by systemic and periocular insulin.

Publications

The retinal proteome in experimental diabetic retinopathy: up-regulation of crystallins and reversal by systemic and periocular insulin.

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