Liver X receptor modulates diabetic retinopathy outcome in a mouse model of streptozotocin-induced diabetes

S Hazra, A Rasheed, A Bhatwadekar, X Wang… - Diabetes, 2012 - Am Diabetes Assoc
S Hazra, A Rasheed, A Bhatwadekar, X Wang, LC Shaw, M Patel, S Caballero
Diabetes, 2012Am Diabetes Assoc
Endothelial progenitor cells (EPCs), critical for mediating vascular repair, are dysfunctional
in a hyperglycemic and/or hypercholesterolemic environment. Their dysfunction contributes
to the progression of diabetic macro-and microvascular complications. Activation of
“cholesterol-sensing” nuclear receptors, the liver X receptors (LXRα/LXRβ), protects against
atherosclerosis by transcriptional regulation of genes important in promoting cholesterol
efflux and inhibiting inflammation. We hypothesized that LXR activation with a synthetic …
Endothelial progenitor cells (EPCs), critical for mediating vascular repair, are dysfunctional in a hyperglycemic and/or hypercholesterolemic environment. Their dysfunction contributes to the progression of diabetic macro- and microvascular complications. Activation of “cholesterol-sensing” nuclear receptors, the liver X receptors (LXRα/LXRβ), protects against atherosclerosis by transcriptional regulation of genes important in promoting cholesterol efflux and inhibiting inflammation. We hypothesized that LXR activation with a synthetic ligand would correct diabetes-induced EPC dysfunction and improve diabetic retinopathy. Studies were performed in streptozotocin (STZ)-injected DBA/2J mice fed a high-fat Western diet (DBA/STZ/WD) and treated with the LXR agonist GW3965 and in LXRα−/−, LXRβ−/−, and LXRα/β−/− mice. Retinas were evaluated for number of acellular capillaries and glial fibrillary acidic protein (GFAP) immunoreactivity. Bone marrow EPCs were analyzed for migratory function and gene expression. Compared with vehicle-treated DBA/STZ/WD mice, GW3965 treated mice showed fewer acellular capillaries and reduced GFAP expression. These mice also exhibited enhanced EPC migration and restoration of inflammatory and oxidative stress genes toward nondiabetic levels. LXRα−/−, LXRβ−/−, and LXRα/β−/− mice developed acellular capillaries and EPC dysfunction similar to the DBA/STZ/WD mice. These studies support a key role for LXR in retinal and bone marrow progenitor dysfunction associated with type 1 diabetes. LXR agonists may represent promising pharmacologic targets for correcting retinopathy and EPC dysfunction.
Am Diabetes Assoc