Proteomic identification of plasma biomarkers in type 2 diabetic nephropathy
Recent advances in quantitative proteomics have offered opportunities to discover plasma proteins as biomarkers for tracking the progression and for understanding the molecular mechanisms of diabetes. We used quantitative proteomic analysis to identify novel biomarkers of nephropathy in plasma from type 2 diabetic patients. Plasma samples were analyzed by fluorescence two-dimensional differential gel electrophoresis (2D-DIGE), and differentially expressed proteins identification was performed by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Proteomics analysis of the plasma proteome in type 2 diabetes mellitus with nephropathy identified 34 protein spots representing 31 unique proteins. These proteins mainly belonged to metabolic (such as 5'-AMP-activated protein kinase subunit beta-1) and growth regulatory (such as LIM homeobox protein 6) proteins. Additionally, our quantitative proteomic approach has identified numerous previous reported plasma markers of type 2 diabetes mellitus such as apolipoprotein A-I and ficolin-3. On the contrary, we have presented several putative type 2 diabetes mellitus biomarkers including calpain-7 and choline/ethanolamine kinase which have not been reported and may be associated with the progression and development of the disease. The potential of utilizing these markers for screening and treating type 2 diabetes mellitus warrants further investigation. Collectively, our results show that the proteins identified in this study may constitute potential biomarkers for the diagnosis of type 2 diabetics with nephropathy.