Guangxin Chen

This project is designed to find the complement protein expression pattern in patients with different APOE genotypes based the mass spectrometer (MS) data. Apolipoprotein E (APOE) gene is one of the strongest risk factors found so far. Some evidence identifies a causal role of complement pathways in AD, suggesting that complement pathway may play a crucial role in the AD pathology of people carrying E2 allele. In this project, I tried to address two research questions: First, is there a difference for complement related proteins expression between AD patients and healthy control of the same genotype? Second, is there a difference in expression and protein interaction pattern for complement related proteins among APOE genotypes for AD patients? I used the dataset of Dai et al. to identify the differential expressed pattern for complement proteins. The identified differential expressed proteins then went through correlation analysis conducted by R package (e.g., WGCNA) to cluster similar proteins into one module. Finally, I conducted protein-protein interaction (PPI) network analysis for proteins in each module by searching those proteins in composite PPI database. a significant difference of complement related proteins expression pattern was identified between APOE2 patients and controls. Furthermore, protein networks that interact with complement were different in AD patients with E2 allele compared to other genotypes. Our work may provide potential biomarkers and therapeutic target related to complement pathways for AD.