Abstract
Purpose :
Diabetic Retinopathy (DR) is a complication that causes progressive damage to the retina and is the leading cause of vision loss in adults. Chronic inflammation is accepted as a leading cause of DR pathogenesis, however factors leading to inflammatory changes in diabetic retina are not fully understood. Liver X Receptors α/β (LXR) are well accepted anti-inflammatory regulators. It has been shown the LXR can be activated through deacetylation by nutrient-sensing deacetylase SIRT1. Both SIRT1 and LXR levels are decreased in diabetic retina. Thus, we hypothesize that serum starvation will lead to increased levels of SIRT1, resulting in decreased levels of inflammation in retinal endothelial cells.
Methods :
Bovine Retinal Endothelial cells (BRECs) were isolated and cultured according to published protocols. Cells were treated with pro-inflammatory stimulus, TNFα (10ng/ml) and/or serum starved (0% Fetal Bovine Serum) for 24hrs. mRNA expression levels were analyzed via qRT-PCR. LXR total protein levels were analyzed via western blot analysis.
Results :
TNFα has been shown to play an important role in the initiation of inflammation and has been shown to be responsible for the expression of adhesion molecules such as ICAM-1. Treatment with TNFα, caused a significant decrease in SIRT1 expression levels (n=6, p=0.0126). Serum starvation for 24hrs caused a significant increase in SIRT1 mRNA levels (n=6, p=0.0031) and LXR protein levels (n=3, p=0.0069). Additionally, treatment with TNFα caused a significant increase in ICAM1 levels (n=6, p<0.001) while serum starvation led to a significant decrease in inflammation markers including ICAM1 (n=6, p<0.001).
Conclusions :
TNFα treatment caused a significant decrease in SIRT1 levels and lead to increased levels of inflammation in BRECs. Activation of SIRT1, via serum starvation, lead to decreased levels of the vascular adhesion molecule, ICAM1. This data suggests that amplified SIRT1 expression has the potential to reduce DR pathogenesis brought on by retinal inflammatory changes.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.