BACKGROUND: Transforming growth factor beta (TGF-beta) plays an important role in diabetic retinopathy. betaIG-H3 is a downstream target molecule of TGF-beta that may participate in the pathogenesis of diabetic retinopathy and in particular in the loss of pericytes during early pathological changes. METHODS: We observed bovine retinal pericytes apoptosis and the increased expression of TGF-beta and betaIG-H3 induced by high concentrations of glucose in the cell culture media. An anti-TGF-beta antibody was used to block glucose-induced retinal pericytes apoptosis. Retinal pericytes were also transfected with cDNA encodings either wild-type or mutant betaIG-H3 lacking Arg-Gly-Asp (RGD) sequences in order to validate the effects of betaIG-H3 and RGD signalling on retinal pericytes apoptosis. RESULTS: A cell death-detecting enzyme-linked immunosorbent assay revealed that 25 mM glucose significantly increased cell death compared with 5.5 mM glucose after 5 or 7 days of exposure (P < 0.01). High glucose significantly increased the TGF-beta levels as compared with 5.5 mM glucose after 5 days, and betaIG-H3 levels after 3, 5 and 7 days of exposure (P < 0.01). TGF-beta increased cell death and betaIG-H3 levels in a dose-dependent manner, with a maximal effect observed at 1 ng/mL. An anti-TGF-beta antibody nearly completely blocked high glucose-induced cell death. Wild-type betaIG-H3-transfected cells showed a significant increase in cell death as compared with mutant betaIG-H3-transfected (Mycb-c) cells, untransfected or mock-transfected cells. CONCLUSION: These results suggest that hyperglycaemia-induced expression of TGF-beta and betaIG-H3 contributes to accelerated retinal pericytes apoptosis. betaIG-H3 induces pericytes apoptosis through its RGD motif, which may constitute an important pathogenic mechanism leading to pericytes loss in diabetic retinopathy.
BACKGROUND: Transforming growth factor beta (TGF-beta) plays an important role in diabetic retinopathy. betaIG-H3 is a downstream target molecule of TGF-beta that may participate in the pathogenesis of diabetic retinopathy and in particular in the loss of pericytes during early pathological changes. METHODS: We observed bovine retinal pericytes apoptosis and the increased expression of TGF-beta and betaIG-H3 induced by high concentrations of glucose in the cell culture media. An anti-TGF-beta antibody was used to block glucose-induced retinal pericytes apoptosis. Retinal pericytes were also transfected with cDNA encodings either wild-type or mutant betaIG-H3 lacking Arg-Gly-Asp (RGD) sequences in order to validate the effects of betaIG-H3 and RGD signalling on retinal pericytes apoptosis. RESULTS: A cell death-detecting enzyme-linked immunosorbent assay revealed that 25 mM glucose significantly increased cell death compared with 5.5 mM glucose after 5 or 7 days of exposure (P < 0.01). High glucose significantly increased the TGF-beta levels as compared with 5.5 mM glucose after 5 days, and betaIG-H3 levels after 3, 5 and 7 days of exposure (P < 0.01). TGF-beta increased cell death and betaIG-H3 levels in a dose-dependent manner, with a maximal effect observed at 1 ng/mL. An anti-TGF-beta antibody nearly completely blocked high glucose-induced cell death. Wild-type betaIG-H3-transfected cells showed a significant increase in cell death as compared with mutant betaIG-H3-transfected (Mycb-c) cells, untransfected or mock-transfected cells. CONCLUSION: These results suggest that hyperglycaemia-induced expression of TGF-beta and betaIG-H3 contributes to accelerated retinal pericytes apoptosis. betaIG-H3 induces pericytes apoptosis through its RGD motif, which may constitute an important pathogenic mechanism leading to pericytes loss in diabetic retinopathy.
Authors: B S Betts-Obregon; A A Mondragon; A S Mendiola; R G LeBaron; R Asmis; T Zou; F Gonzalez-Fernandez; A T Tsin Journal: Eye (Lond) Date: 2016-08-26 Impact factor: 3.775
Authors: Albert A Mondragon; Brandi S Betts-Obregon; Robert J Moritz; Kalpana Parvathaneni; Mary M Navarro; Hong Seok Kim; Chi Fung Lee; Richard G LeBaron; Reto Asmis; Andrew T Tsin Journal: Apoptosis Date: 2015-01 Impact factor: 4.677
Authors: Robert J Moritz; Richard G LeBaron; Clyde F Phelix; Rajesha Rupaimoole; Hong Seok Kim; Andrew Tsin; Reto Asmis Journal: Int J Clin Med Date: 2016-07-21