Involvement of caspase-10 in advanced glycation end-product-induced apoptosis of bovine retinal pericytes in culture.
Apoptosis appears to be the death mechanism of pericyte loss observed in diabetic retinopathy. We have previously shown that advanced glycation end-products (AGE-MGX) induce apoptosis of retinal pericytes in culture associated with diacylglycerol (DAG)/ceramide production. In the present study, we investigated possible caspase involvement in this process. Bovine retinal pericytes (BRP) were cultured with AGE-MGX and apoptosis examined after annexin V staining. Effects of peptidic inhibitors of caspases were determined on DAG/ceramide production and apoptosis. Pan-caspase inhibitor z-VAD-fmk (50 microM) was able to inhibit both DAG/ceramide production and apoptosis, whereas caspase-3-like inhibitor z-DEVD-fmk (50 microM) or caspase-9 inhibitor z-LEHD-fmk (50 microM) was only active on apoptosis. This differential effect strongly suggests involvement of initiator caspase(s) upstream and effector caspase(s) downstream DAG/ceramide production in AGE-mediated apoptosis. Pericyte treatment with caspase-8 inhibitor z-IETD-fmk (50 microM) did not protect cells against AGE-induced apoptosis and we failed to detect caspase-8 in pericytes by immunoblotting assay. Interestingly, one inhibitor of caspase-10 and related caspases z-AEVD-fmk (50 microM) inhibited both AGE-MGX-induced apoptosis and DAG/ceramide formation in pericytes. Cleavage of caspase-10 precursor into its active subunits was demonstrated by immunoblotting assay in pericytes incubated with AGE-MGX. These results strongly suggest that caspase-10, but not caspase-8, might be involved in the early phase of AGE-induced pericyte apoptosis, in contrast to caspase-9 and -3-like enzymes involved after DAG/ceramide production. This finding may provide new therapeutic perspectives for early treatment in diabetic retinopathy.
Lecomte
Marc
M
Diabetic Microangiopathy Unit, MERCK Santé-INSERM U352, INSA-Lyon, Building Louis Pasteur, 11 Av. J. Capelle, F-69621 Villeurbanne Cedex, France. marc.lecomte@merck.fr
Denis
Ulriche
U
Ruggiero
Daniel
D
Lagarde
Michel
M
Wiernsperger
Nicolas
N
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053455:Caspase 10; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism*; D002417:Cattle; D017127:Glycation End Products, Advanced / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology; D012160:Retina / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology
D000590:Amino Acid Chloromethyl Ketones; D017127:Glycation End Products, Advanced; D009842:Oligopeptides; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C403754:benzyloxycarbonyl-leucyl-glutamyl-histidyl-aspartic acid fluoromethyl ketone; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D053455:Caspase 10; D053181:Caspase 8; D020169:Caspases