Identification of Plasma Proteomic Biomarkers in Patients with Mild Cognitive Impairment.

Plasma proteomic profiling may provide novel biomarkers for the identification of mild cognitive impairment (MCI). The early diagnosis of MCI still remains a challenging task due to its diverse origin. Currently, molecular approaches have been used to identify MCI diversified origin as its onset is governed by a variety of molecular changes. Therefore, we aimed to find out molecular alteration in plasma using proteomics in patients with MCI for early detection of prodromal Alzheimer's disease (AD). To achieve this, we performed two-dimensional (2-D) gel electrophoresis coupled with MALDI-TOF/MS, which is used to analyze the differentially expressed proteins. In our study, we found three significantly altered proteins. Out of three differentially expressed proteins, one was downregulated and two were upregulated in MCI individuals as compared to control. Further, In silico analysis showed that identified proteins are involved in pathways such as complement and coagulation cascades, platelet activation and AD. STRING interaction network analysis revealed that the majority of proteins including apolipoprotein E (APO-E) have a common association with Transthyretin (TTR) and fibrinogen chain beta (FGB) protein. This suggests that APO-E, TTR and FGB are the key proteins with which other proteins interact to exert other biological functions. Conclusively, these proteins showing differential expression in the plasma might be used as a potent signature in blood for the diagnosis of MCI individuals.