Retinal microglial activation and inflammation induced by amadori-glycated albumin in a rat model of diabetes

Ahmed S. Ibrahim, Azza B. El-Remessy, Suraporn Matragoon, Wenbo Zhang, Yogin Patel, Sohail Khan, Mohammed M. Al-Gayyar, Mamdouh M. El-Shishtawy, Gregory I. Liou

Research output: Contribution to journalArticle

105 Citations (Scopus)

Abstract

OBJECTIVE - During diabetes, retinal microglial cells are activated to release inflammatory cytokines that initiate neuronal loss and blood-retinal barrier breakdown seen in diabetic retinopathy (DR). The mechanism by which diabetes activates microglia to release those inflammatory mediators is unclear and was therefore elucidated. RESEARCH DESIGN AND METHODS - Microglia activation was characterized in streptozocin-injected rats and in isolated microglial cells using immunofluorescence, enzyme-linked immunosorbent assay, RT-PCR, and Western blot analyses. RESULTS - In 8-week diabetic retina, phospho- extracellular signal-related kinase (ERK) and P38 mitogen-activated protein kinases were localized in microglia, but not in Mueller cells or astrocytes. At the same time, Amadori-glycated albumin (AGA)-like epitopes were featured in the regions of microglia distribution, implicating a pathogenic effect on microglial activation. To test this, diabetic rats were treated intravitreally with A717, a specific AGA-neutralizing antibody, or murine IgG. Relative to nondiabetic rats, diabetic rats (IgG-treated) manifested 3.9- and 7.9-fold increases in Iba-1 and tumor necrosis factor (TNF)-α mRNAs, respectively. Treatment of diabetic rats with A717 significantly attenuated overexpression of these mRNAs. Intravitreal injection of AGA per se in normal rats resulted in increases of Iba-1 expression and TNF-α release. Guided by these results, a cultured retinal microglia model was developed to study microglial response after AGA treatment and the mechanistic basis behind this response. The results showed that formation of reactive oxygen species and subsequent activation of ERK and P38, but not Jun NH2-terminal kinase, are molecular events underpinning retinal microglial TNF-α release during AGA treatment. CONCLUSIONS - These results provide new insights in understanding the pathogenesis of early DR, showing that the accumulated AGA within the diabetic retina elicits the microglial activation and secretion of TNF-α. Thus, intervention trials with agents that neutralize AGA effects may emerge as a new therapeutic approach to modulate early pathologic pathways long before the occurrence of vision loss among patients with diabetes.

Original languageEnglish (US)
Pages (from-to)1122-1133
Number of pages12
JournalDiabetes
Volume60
Issue number4
DOIs
StatePublished - Apr 2011
Externally publishedYes

Fingerprint

Microglia
Inflammation
Tumor Necrosis Factor-alpha
Diabetic Retinopathy
Retina
Phosphotransferases
Immunoglobulin G
Blood-Retinal Barrier
Messenger RNA
Intravitreal Injections
JNK Mitogen-Activated Protein Kinases
p38 Mitogen-Activated Protein Kinases
Therapeutics
Streptozocin
glycosylated serum albumin
Neutralizing Antibodies
Astrocytes
Fluorescent Antibody Technique
Epitopes
Reactive Oxygen Species

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

Cite this

Ibrahim, A. S., El-Remessy, A. B., Matragoon, S., Zhang, W., Patel, Y., Khan, S., ... Liou, G. I. (2011). Retinal microglial activation and inflammation induced by amadori-glycated albumin in a rat model of diabetes. Diabetes, 60(4), 1122-1133. https://doi.org/10.2337/db10-1160

Retinal microglial activation and inflammation induced by amadori-glycated albumin in a rat model of diabetes. / Ibrahim, Ahmed S.; El-Remessy, Azza B.; Matragoon, Suraporn; Zhang, Wenbo; Patel, Yogin; Khan, Sohail; Al-Gayyar, Mohammed M.; El-Shishtawy, Mamdouh M.; Liou, Gregory I.

In: Diabetes, Vol. 60, No. 4, 04.2011, p. 1122-1133.

Research output: Contribution to journalArticle

Ibrahim, AS, El-Remessy, AB, Matragoon, S, Zhang, W, Patel, Y, Khan, S, Al-Gayyar, MM, El-Shishtawy, MM & Liou, GI 2011, 'Retinal microglial activation and inflammation induced by amadori-glycated albumin in a rat model of diabetes', Diabetes, vol. 60, no. 4, pp. 1122-1133. https://doi.org/10.2337/db10-1160
Ibrahim, Ahmed S. ; El-Remessy, Azza B. ; Matragoon, Suraporn ; Zhang, Wenbo ; Patel, Yogin ; Khan, Sohail ; Al-Gayyar, Mohammed M. ; El-Shishtawy, Mamdouh M. ; Liou, Gregory I. / Retinal microglial activation and inflammation induced by amadori-glycated albumin in a rat model of diabetes. In: Diabetes. 2011 ; Vol. 60, No. 4. pp. 1122-1133.
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abstract = "OBJECTIVE - During diabetes, retinal microglial cells are activated to release inflammatory cytokines that initiate neuronal loss and blood-retinal barrier breakdown seen in diabetic retinopathy (DR). The mechanism by which diabetes activates microglia to release those inflammatory mediators is unclear and was therefore elucidated. RESEARCH DESIGN AND METHODS - Microglia activation was characterized in streptozocin-injected rats and in isolated microglial cells using immunofluorescence, enzyme-linked immunosorbent assay, RT-PCR, and Western blot analyses. RESULTS - In 8-week diabetic retina, phospho- extracellular signal-related kinase (ERK) and P38 mitogen-activated protein kinases were localized in microglia, but not in Mueller cells or astrocytes. At the same time, Amadori-glycated albumin (AGA)-like epitopes were featured in the regions of microglia distribution, implicating a pathogenic effect on microglial activation. To test this, diabetic rats were treated intravitreally with A717, a specific AGA-neutralizing antibody, or murine IgG. Relative to nondiabetic rats, diabetic rats (IgG-treated) manifested 3.9- and 7.9-fold increases in Iba-1 and tumor necrosis factor (TNF)-α mRNAs, respectively. Treatment of diabetic rats with A717 significantly attenuated overexpression of these mRNAs. Intravitreal injection of AGA per se in normal rats resulted in increases of Iba-1 expression and TNF-α release. Guided by these results, a cultured retinal microglia model was developed to study microglial response after AGA treatment and the mechanistic basis behind this response. The results showed that formation of reactive oxygen species and subsequent activation of ERK and P38, but not Jun NH2-terminal kinase, are molecular events underpinning retinal microglial TNF-α release during AGA treatment. CONCLUSIONS - These results provide new insights in understanding the pathogenesis of early DR, showing that the accumulated AGA within the diabetic retina elicits the microglial activation and secretion of TNF-α. Thus, intervention trials with agents that neutralize AGA effects may emerge as a new therapeutic approach to modulate early pathologic pathways long before the occurrence of vision loss among patients with diabetes.",
author = "Ibrahim, {Ahmed S.} and El-Remessy, {Azza B.} and Suraporn Matragoon and Wenbo Zhang and Yogin Patel and Sohail Khan and Al-Gayyar, {Mohammed M.} and El-Shishtawy, {Mamdouh M.} and Liou, {Gregory I.}",
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T1 - Retinal microglial activation and inflammation induced by amadori-glycated albumin in a rat model of diabetes

AU - Ibrahim, Ahmed S.

AU - El-Remessy, Azza B.

AU - Matragoon, Suraporn

AU - Zhang, Wenbo

AU - Patel, Yogin

AU - Khan, Sohail

AU - Al-Gayyar, Mohammed M.

AU - El-Shishtawy, Mamdouh M.

AU - Liou, Gregory I.

PY - 2011/4

Y1 - 2011/4

N2 - OBJECTIVE - During diabetes, retinal microglial cells are activated to release inflammatory cytokines that initiate neuronal loss and blood-retinal barrier breakdown seen in diabetic retinopathy (DR). The mechanism by which diabetes activates microglia to release those inflammatory mediators is unclear and was therefore elucidated. RESEARCH DESIGN AND METHODS - Microglia activation was characterized in streptozocin-injected rats and in isolated microglial cells using immunofluorescence, enzyme-linked immunosorbent assay, RT-PCR, and Western blot analyses. RESULTS - In 8-week diabetic retina, phospho- extracellular signal-related kinase (ERK) and P38 mitogen-activated protein kinases were localized in microglia, but not in Mueller cells or astrocytes. At the same time, Amadori-glycated albumin (AGA)-like epitopes were featured in the regions of microglia distribution, implicating a pathogenic effect on microglial activation. To test this, diabetic rats were treated intravitreally with A717, a specific AGA-neutralizing antibody, or murine IgG. Relative to nondiabetic rats, diabetic rats (IgG-treated) manifested 3.9- and 7.9-fold increases in Iba-1 and tumor necrosis factor (TNF)-α mRNAs, respectively. Treatment of diabetic rats with A717 significantly attenuated overexpression of these mRNAs. Intravitreal injection of AGA per se in normal rats resulted in increases of Iba-1 expression and TNF-α release. Guided by these results, a cultured retinal microglia model was developed to study microglial response after AGA treatment and the mechanistic basis behind this response. The results showed that formation of reactive oxygen species and subsequent activation of ERK and P38, but not Jun NH2-terminal kinase, are molecular events underpinning retinal microglial TNF-α release during AGA treatment. CONCLUSIONS - These results provide new insights in understanding the pathogenesis of early DR, showing that the accumulated AGA within the diabetic retina elicits the microglial activation and secretion of TNF-α. Thus, intervention trials with agents that neutralize AGA effects may emerge as a new therapeutic approach to modulate early pathologic pathways long before the occurrence of vision loss among patients with diabetes.

AB - OBJECTIVE - During diabetes, retinal microglial cells are activated to release inflammatory cytokines that initiate neuronal loss and blood-retinal barrier breakdown seen in diabetic retinopathy (DR). The mechanism by which diabetes activates microglia to release those inflammatory mediators is unclear and was therefore elucidated. RESEARCH DESIGN AND METHODS - Microglia activation was characterized in streptozocin-injected rats and in isolated microglial cells using immunofluorescence, enzyme-linked immunosorbent assay, RT-PCR, and Western blot analyses. RESULTS - In 8-week diabetic retina, phospho- extracellular signal-related kinase (ERK) and P38 mitogen-activated protein kinases were localized in microglia, but not in Mueller cells or astrocytes. At the same time, Amadori-glycated albumin (AGA)-like epitopes were featured in the regions of microglia distribution, implicating a pathogenic effect on microglial activation. To test this, diabetic rats were treated intravitreally with A717, a specific AGA-neutralizing antibody, or murine IgG. Relative to nondiabetic rats, diabetic rats (IgG-treated) manifested 3.9- and 7.9-fold increases in Iba-1 and tumor necrosis factor (TNF)-α mRNAs, respectively. Treatment of diabetic rats with A717 significantly attenuated overexpression of these mRNAs. Intravitreal injection of AGA per se in normal rats resulted in increases of Iba-1 expression and TNF-α release. Guided by these results, a cultured retinal microglia model was developed to study microglial response after AGA treatment and the mechanistic basis behind this response. The results showed that formation of reactive oxygen species and subsequent activation of ERK and P38, but not Jun NH2-terminal kinase, are molecular events underpinning retinal microglial TNF-α release during AGA treatment. CONCLUSIONS - These results provide new insights in understanding the pathogenesis of early DR, showing that the accumulated AGA within the diabetic retina elicits the microglial activation and secretion of TNF-α. Thus, intervention trials with agents that neutralize AGA effects may emerge as a new therapeutic approach to modulate early pathologic pathways long before the occurrence of vision loss among patients with diabetes.

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