RESUMO
Albumin is one of the most abundant plasma proteins and is heavily glycated in diabetes. In this study, we have addressed whether variation in the albumin levels influence glycation of plasma proteins and HbA1c. The study was performed in three systems: (1) streptozotocin (STZ)-induced diabetic mice plasma, (2) diabetic clinical plasma, and (3) in vitro glycated plasma. Diabetic mice and clinical plasma samples were categorized as diabetic high albumin plasma (DHAP) and diabetic low albumin plasma (DLAP) on the basis of their albumin levels. For the in vitro experiment, two albumin levels, high albumin plasma (HAP) and low albumin plasma (LAP), were created by differential depletion of plasma albumin. Protein glycation was studied by using a combination of two-dimensional electrophoresis (2DE), Western blotting, and LC-MS(E). In both mice and clinical experiments, an increased plasma protein glycation was observed in DLAP than in DHAP. Additionally, plasma albumin levels were negatively correlated with HbA1c. The in vitro experiment with differential depletion of albumin mechanistically showed that the low albumin levels are associated with increased plasma protein glycation and that albumin competes for glycation with other plasma proteins.
Assuntos
Diabetes Mellitus/sangue , Hemoglobinas Glicadas/metabolismo , Glicoproteínas/sangue , Albumina Sérica/metabolismo , Animais , Glicemia/metabolismo , Western Blotting , Análise por Conglomerados , Diabetes Mellitus Experimental/sangue , Eletroforese em Gel Bidimensional , Hemoglobinas Glicadas/química , Produtos Finais de Glicação Avançada/química , Produtos Finais de Glicação Avançada/metabolismo , Glicoproteínas/química , Glicosilação , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Modelos Biológicos , Proteômica , Albumina Sérica/químicaRESUMO
Cancer is associated with increased glycolysis and carbonyl stress. In view of this, AGE modified proteins were identified from clinical breast cancer tissue using 2DE-immunoblot and mass-spectrometry. These proteins were identified to be serotransferrin, fibrinogen gamma chain, glycerol-3-phosphate dehydrogenase, lactate dehydrogenase, annexin II, prohibitin and peroxiredoxin 6, which have established role in cancer. Further, RAGE expression and its downstream signaling proteins NADPH oxidase and NF-kB were studied. Role of these AGE modified proteins and RAGE signaling in breast cancer is discussed.
Assuntos
Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Produtos Finais de Glicação Avançada/metabolismo , Proteínas Quinases Ativadas por Mitógeno/biossíntese , Proteínas de Neoplasias/metabolismo , Receptor para Produtos Finais de Glicação Avançada/biossíntese , Sequência de Aminoácidos , Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/metabolismo , Feminino , Humanos , Dados de Sequência Molecular , NADPH Oxidases/metabolismo , NF-kappa B/metabolismo , Invasividade Neoplásica , Processamento de Proteína Pós-Traducional , Receptor ErbB-2/análise , Receptor ErbB-2/metabolismoRESUMO
Proteomic approaches aid in gaining a better understanding of the pathophysiology of diabetic complications. In view of this, differential protein expression in diabetic plasma samples was studied by a combination of proteomic and western blot analyses. Diabetic plasma samples were categorized based on glycated haemoglobin levels as controlled diabetes (CD; 7-8%), poorly controlled diabetes (PCD; >8%) and non-diabetic control (ND;<6.4%). Two-dimensional electrophoresis and liquid chromatographymass spectrometry revealed differential expression of proteins including upregulation of fibrinogen and haptoglobin and downregulation of vitamin D binding protein, α-1-antitrypsin, transthyretin and apolipoprotein A1 (Apo A1) in diabetic compared with non-diabetic plasma samples. Amongst these proteins, Apo A1 downregulation was prominent in PCD. Downregulation of Apo A1 may serve as an early predictive marker of diabetic complications.