sorbinil and Inflammation

Prevention of diabetic retinopathy would benefit from availability of drugs that preempt the effects of hyperglycemia on retinal vessels. We aimed to identify candidate drug targets by investigating the molecular effects of drugs that prevent retinal capillary demise in the diabetic rat.. We examined the gene expression profile of retinal vessels isolated from rats with 6 months of streptozotocin-induced diabetes and compared it with that of control rats. We then tested whether the aldose reductase inhibitor sorbinil and aspirin, which have different mechanisms of action, prevented common molecular abnormalities induced by diabetes. The Affymetrix GeneChip Rat Genome 230 2.0 array was complemented by real-time RT-PCR, immunoblotting, and immunohistochemistry.. The retinal vessels of diabetic rats showed differential expression of 20 genes of the transforming growth factor (TGF)-beta pathway, in addition to genes involved in oxidative stress, inflammation, vascular remodeling, and apoptosis. The complete loop of TGF-beta signaling, including Smad2 phosphorylation, was enhanced in the retinal vessels, but not in the neural retina. Sorbinil normalized the expression of 71% of the genes related to oxidative stress and 62% of those related to inflammation. Aspirin had minimal or no effect on these two categories. The two drugs were instead concordant in reducing the upregulation of genes of the TGF-beta pathway (55% for sorbinil and 40% for aspirin) and apoptosis (74 and 42%, respectively).. Oxidative and inflammatory stress is the distinct signature that the polyol pathway leaves on retinal vessels. TGF-beta and apoptosis are, however, the ultimate targets to prevent the capillary demise in diabetic retinopathy.

Topics: Animals; Aspirin; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Gene Expression Profiling; Gene Expression Regulation; Imidazolidines; Inflammation; Oligonucleotide Array Sequence Analysis; Oxidative Stress; Rats; Receptors, Transforming Growth Factor beta; Retina; Retinal Vessels; Reverse Transcriptase Polymerase Chain Reaction; RNA; Transforming Growth Factor beta

Increased expression of adhesion molecules by the activated endothelium is a critical feature of vascular inflammation associated with several disease states such as atherosclerosis. However, mechanisms regulating the endothelial induction of adhesion molecules are not entirely clear. Herein we report that inhibition of the polyol pathway enzyme aldose reductase (AR) prevents the increase in ICAM-1 and VCAM-1 in human umbilical vein endothelial cells (HUVECs) and decreases monocyte adhesion to these cells. In TNF-alpha-stimulated HUVECs, treatment with AR inhibitors sorbinil and tolrestat diminished NF-kappaB activity, phosphorylation and degradation of Ikappa-Balpha, and the nuclear translocation of NF-kappaB. Inhibition of AR abrogated TNF-alpha-induced activation and membrane translocation of PKC, and antisense ablation of AR prevented both TNF-alpha-induced PKC and NF-kappaB activation. However, inhibition of AR did not prevent phorbol ester-induced activation of PKC or NF-kappaB, indicating that inhibition of AR does prevents events upstream of PKC activation. These results identify a novel regulator of endothelial activation and suggest that AR is an obligatory mediator of TNF-alpha signaling leading to an increase in the expression of adhesion molecules and increased binding of monocytes to the endothelium.

Topics: Aldehyde Reductase; Cells, Cultured; Endothelial Cells; Endothelium, Vascular; Enzyme Activation; Enzyme Inhibitors; Humans; I-kappa B Proteins; Imidazolidines; Inflammation; Intercellular Adhesion Molecule-1; Monocytes; Naphthalenes; NF-kappa B; NF-KappaB Inhibitor alpha; Oligodeoxyribonucleotides, Antisense; Phosphorylation; Protein Kinase C; Protein Processing, Post-Translational; Protein Transport; Transcriptional Activation; Transfection; Tumor Necrosis Factor-alpha; Umbilical Veins; Vascular Cell Adhesion Molecule-1