Guzyk M. Poly-ADP-ribosylation of nuclear proteins in Diabetes Mellitus

Object: poly-ADP-ribosylation of nuclear proteins in type 1 Diabetes Mellitus. Aim: to clarify the features of processes of poly-ADP-ribosylation of nuclear proteins in the tissues of various organs of rats and their role in the development of diabetes and its complications. Methods: biochemical and optical (spectrophotometry, spectrofluorometry, flow cytometry, light and confocal microscopy), physicochemical (gel electrophoresis to separate the proteins), molecular biology (polymerase chain reaction), immunochemical and cytological methods (immunoblotting and immunohistochemistry) and eukaryotic cell culture techniques (cultivation and assessment of their functional state). The process of poly-ADP-ribosylation and the action of PARP-1 inhibitors (1.5-isoquinolinediol, 3-aminobenzamide and nicotinamide) were shown to be tissue-specific in diabetes and dependent on the intensity of oxidative stress, inflammation and antioxidant defense system capacity. It was found that the most pronounced pathological changes occur in the brain and retina of diabetic rats. Activation of poly-ADP-ribosylation and the reduction of intracellular NAD+ content led to enhanced PARP-1 fragmentation and increased tissue level of NAD-dependent deacetylase SIRT2 that can indicate on the severity of neurodegenerative changes in the brain and retina of diabetic rats. It was shown that the late complications of diabetes are associated with the pathological changes in the retina of diabetic rats, most likely, caused by the rearrangement of the cytoskeletal proteins as well as increased neovascularization. It was identified for the first time the decrease in the fragmentation of both PARP-1 and glial fibrillary acidic protein. The use of structurally distinct inhibitors of PARP-1 in diabetes resulted in partial or complete normalization of diabetes-induced biochemical and functional failures. Their efficiency was revealed to be higher in countering the signs of retinopathy.