Advanced glycation end-products induce apoptosis of bovine retinal pericytes in culture: involvement of diacylglycerol/ceramide production and oxidative stress induction.
One of the earliest changes observed in retinal microvessels in diabetic retinopathy is the selective loss of intramural pericytes. We tested the hypothesis that AGE might be involved in the disappearance of retinal pericytes by apoptosis and further investigated the signaling pathway leading to cell death. Chronic exposure of pericytes to methylglyoxal-modified bovine serum albumin (AGE-BSA) (3 microM) leads to a 3-fold increase of apoptosis (8.9 +/- 1.1%), associated with an increase in cellular ceramide (185 +/- 12%) and diacylglycerol (194 +/- 9%) levels. Ceramide formation was almost inhibited (95%) by an acidic sphingomyelinase inhibitor, desipramine (0.3 microM). Dual inhibition of ceramide (95%) and diacylglycerol (80%) production was observed with a phosphatidylcholine-phospholipase C inhibitor, D609 (9.4 microM). Taken together, these results suggest activation of phosphatidylcholine-phospholipase C coupled to acidic sphingomyelinase. However, both inhibitors only partially protected pericytes against apoptosis, suggesting another apoptotic pathway independent of diacylglycerol/ceramide production. Treatments with various antioxidants completely inhibited pericyte apoptosis, suggesting oxidative stress induction during this apoptotic process. Inhibition of diacylglycerol/ceramide production by N-acetyl-L-cysteine suggests that oxidative stress acts upstream of the two metabolic pathways. AGE treated with metal chelators were also able to induce pericyte apoptosis, suggesting a specific effect of AGE on intracellular oxidative stress independent of redox-active metal ions bound to AGE. In conclusion, these results identify new biochemical targets involved in pericyte loss, which can provide new therapeutic perspectives in diabetic retinopathy.
Denis
Ulriche
U
Diabetic Microangiopathy Unit, LIPHA-INSERM U352, INSA-Lyon, Villeurbanne Cedex, France.
Lecomte
Marc
M
Paget
Clarisse
C
Ruggiero
Daniel
D
Wiernsperger
Nicolas
N
Lagarde
Michel
M
D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001205:Ascorbic Acid / Q000494:pharmacology; D001952:Bridged-Ring Compounds / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D002518:Ceramides / Q000096:biosynthesis*; D002614:Chelating Agents / Q000494:pharmacology; D003891:Desipramine / Q000494:pharmacology; D004075:Diglycerides / Q000096:biosynthesis*; D017127:Glycation End Products, Advanced / Q000494:pharmacology*; D009636:Norbornanes; D018384:Oxidative Stress; D004369:Pentetic Acid / Q000494:pharmacology; D020286:Pericytes / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000096:biosynthesis; D012117:Resins, Synthetic; D012160:Retina / Q000378:metabolism / Q000473:pathology*; D012710:Serum Albumin, Bovine / Q000494:pharmacology*; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors; D013859:Thiocarbamates; D013871:Thiones / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors
C011439:1,2-diacylglycerol; D018759:Adrenergic Uptake Inhibitors; D000970:Antineoplastic Agents; D001952:Bridged-Ring Compounds; D002518:Ceramides; D002614:Chelating Agents; D004075:Diglycerides; D017127:Glycation End Products, Advanced; D009636:Norbornanes; D012333:RNA, Messenger; D012117:Resins, Synthetic; D013859:Thiocarbamates; D013871:Thiones; C081628:advanced glycation end products-bovine serum albumin; C024997:Chelex 100; D012710:Serum Albumin, Bovine; C046498:tricyclodecane-9-yl-xanthogenate; D004369:Pentetic Acid; D010738:Type C Phospholipases; D013108:Sphingomyelin Phosphodiesterase; D001205:Ascorbic Acid; D003891:Desipramine