High-resolution serum proteomic profiling of Alzheimer disease samples reveals disease-specific, carrier-protein-bound mass signatures.
BACKGROUND
Researchers typically search for disease markers using a "targeted" approach in which a hypothesis about the disease mechanism is tested and experimental results either confirm or disprove the involvement of a particular gene or protein in the disease. Recently, there has been interest in developing disease diagnostics based on unbiased quantification of differences in global patterns of protein and peptide masses, typically in blood from individuals with and without disease. We combined a suite of methods and technologies, including novel sample preparation based on carrier-protein capture and biomarker enrichment, high-resolution mass spectrometry, a unique cohort of well-characterized persons with and without Alzheimer disease (AD), and powerful bioinformatic analysis, that add statistical and procedural robustness to biomarker discovery from blood.


METHODS
Carrier-protein-bound peptides were isolated from serum samples by affinity chromatography, and peptide mass spectra were acquired by a matrix-assisted laser desorption/ionization (MALDI) orthogonal time-of-flight (O-TOF) mass spectrometer capable of collecting data over a broad mass range (100 to >300,000 Da) in a single acquisition. Discriminatory analysis of mass spectra was used to process and analyze the raw mass spectral data.


RESULTS
Coupled with the biomarker enrichment protocol, the high-resolution MALDI O-TOF mass spectra provided informative, reproducible peptide signatures. The raw mass spectra were analyzed and used to build discriminant disease models that were challenged with blinded samples for classification.


CONCLUSIONS
Carrier-protein enrichment of disease biomarkers coupled with high-resolution mass spectrometry and discriminant pattern analysis is a powerful technology for diagnostics and population screening. The mass fingerprint model successfully classified blinded AD patient and control samples with high sensitivity and specificity.
Lopez
Mary F
MF
PerkinElmer Life and Analytical Sciences, Boston, MA 02118, USA. mary.lopez@perkinelmer.com
Mikulskis
Alvydas
A
Kuzdzal
Scott
S
Bennett
David A
DA
Kelly
Jeremiah
J
Golenko
Eva
E
DiCesare
Joseph
J
Denoyer
Eric
E
Patton
Wayne F
WF
Ediger
Richard
R
Sapp
Lisa
L
Ziegert
Tillmann
T
Lynch
Christopher
C
Kramer
Susan
S
Whiteley
Gordon R
GR
Wall
Michael R
MR
Mannion
David P
DP
Della Cioppa
Guy
G
Rakitan
John S
JS
Wolfe
Gershon M
GM
D000544:Alzheimer Disease / Q000097:blood / Q000145:classification / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D010455:Peptides / Q000097:blood / Q000737:chemistry* / Q000302:isolation & purification; D040901:Proteomics / Q000379:methods*; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D015415:Biomarkers; D010455:Peptides