Analysis of plasma proteins using 2D gels and novel fluorescent probes: in search of blood based biomarkers for Alzheimer’s disease

Proteome Science

Jennifer A. Vance¹  James D. Doecke²  Ralph Martins³  Anne M. Roberts⁴  Blaine R. Roberts⁴  Paul A. Grieco⁵  Edward A. Dratz⁵  Benjamin D. Reeves⁵  David Ames⁶  Chris J. Fowler⁶  Rebecca L. Rumble⁶  Scott B. Laffoon⁶  Colin L. Masters⁶  Brett Trounson⁶  Kelly K. Pertile⁶  Ashley I. Bush⁶ 

[1] AIT Bioscience;Australian e-Health Research Centre, CSIRO and Cooperative Research Centre of Mental Health, Royal Brisbane and Women’s Hospital;Cooperative Research Centre for Mental Health;Department of Biochemistry, Emory School of Medicine;Department of Chemistry and Biochemistry, Montana State University;Florey Institute of Neuroscience and Mental Health and The University of Melbourne Dementia Research Centre;

关键词: Proteomics;    2D-PAGE;    Alzheimer’s disease;    Biomarkers;    Plasma;    APOE;   

DOI  :  10.1186/s12953-021-00185-9

来源: DOAJ

【 摘 要 】

Abstract Background The Australian Imaging and Biomarker Lifestyle (AIBL) study of aging is designed to aid the discovery of biomarkers. The current study aimed to discover differentially expressed plasma proteins that could yield a blood-based screening tool for Alzheimer’s disease. Methods The concentration of proteins in plasma covers a vast range of 12 orders of magnitude. Therefore, to search for medium to low abundant biomarkers and elucidate mechanisms of AD, we immuno-depleted the most abundant plasma proteins and pre-fractionated the remaining proteins by HPLC, prior to two-dimensional gel electrophoresis. The relative levels of approximately 3400 protein species resolved on the 2D gels were compared using in-gel differential analysis with spectrally resolved fluorescent protein detection dyes (Zdyes™). Here we report on analysis of pooled plasma samples from an initial screen of a sex-matched cohort of 72 probable AD patients and 72 healthy controls from the baseline time point of AIBL. Results We report significant changes in variants of apolipoprotein E, haptoglobin, α1 anti-trypsin, inter-α trypsin inhibitor, histidine-rich glycoprotein, and a protein of unknown identity. α1 anti-trypsin and α1 anti-chymotrypsin demonstrated plasma concentrations that were dependent on APOE ε4 allele dose. Our analysis also identified an association with the level of Vitamin D binding protein fragments and complement factor I with sex. We then conducted a preliminary validation study, on unique individual samples compared to the discovery cohort, using a targeted LC-MS/MS assay on a subset of discovered biomarkers. We found that targets that displayed a high degree of isoform specific changes in the 2D gels were not changed in the targeted MS assay which reports on the total level of the biomarker. Conclusions This demonstrates that further development of mass spectrometry assays is needed to capture the isoform complexity that exists in theses biological samples. However, this study indicates that a peripheral protein signature has potential to aid in the characterization of AD.

【 授权许可】

Unknown