May 2008
Volume 49, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2008
Oxidative Stress Downregulates Glucose Transport in Retinal Endothelial Cells by a Proteasome-Dependent Mechanism
Author Affiliations & Notes
  • P. C. Pereira
    Center of Ophthalmology, IBILI-Faculty of Medicine of Univ of Coimbra, Coimbra, Portugal
  • R. Fernandes
    Center of Ophthalmology, IBILI-Faculty of Medicine of Univ of Coimbra, Coimbra, Portugal
  • Footnotes
    Commercial Relationships  P.C. Pereira, None; R. Fernandes, None.
  • Footnotes
    Support  FCT GRANTS: POCTI/SAU-OBS/57772 and POCI/SAU-MMO/57216/2004
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 4910. doi:https://doi.org/
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      P. C. Pereira, R. Fernandes; Oxidative Stress Downregulates Glucose Transport in Retinal Endothelial Cells by a Proteasome-Dependent Mechanism. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4910. doi: https://doi.org/.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose: : Increased oxidative stress is implicated in the pathogenesis of diabetic complications, including diabetic retinopathy. The objective of this study is to assess the effect of oxidative stress in regulating GLUT-1 dependent glucose transport in retinal endothelial cells.

Methods: : Retinal endothelial cells in culture (TR-iBRB) were subjected to oxidative stress by incubation with glucose oxidase. Formation of protein carbonyls was used as a marker of oxidative damage to TR-iBRB. Level of GLUT1 mRNA was determined by real time RT-PCR. GLUT1 protein levels were determined by western blot. Where appropriate, the pool of GLUT-1 present at plasma membrane was assessed following biotinylation of the membrane proteins. The glucose transport into endothelial cells and activity of GLUT-1 were measured by 3H-deoxyglucose uptake. Subcellular distribution of GLUT-1 was assessed by fluorescence confocal microscopy.

Results: : Incubation of endothelial cells with glucose oxidase leads to an accumulation of oxidized proteins. Oxidative stress also induces a decrease in the levels of both GLUT-1 mRNA and protein. Biotinylation assays and confocal microscopy further revealed that exposure to oxidative stress reduces the pool of GLUt-1 present at plasma membrane. Consistently, glucose transport, as revealed by 3H-deoxyglucose uptake, is decreased under oxidative stress. Incubation of TR-iBRB, previously exposed to oxidative stress, with the proteasome inhibitors MG-132 or lactacystine restores glucose transport to control levels.

Conclusions: : Data suggested that exposure of retinal endothelial cells to oxidative stress leads to a downregulation of glucose transport, which presumably results both from a down-regulation of GLUT-1 production and a proteasome-dependent subcellular re-distribution of the glucose transporter. The reduction of GLUT-1 at plasma membrane, induced by increased oxidative stress, may contribute for the deregulation of glucose homeostasis in diabetes.

Keywords: diabetic retinopathy • oxidation/oxidative or free radical damage • retinal degenerations: cell biology 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×