Biomarkers in Alzheimer's Disease Analysis
by Mass Spectometry- Based Proteomics
BIOMARKER: substance used as measurable indicator of a
particular biological state (normal or pathologic)
IT SHOULD REFLECT: progression of disease
providing better prognosis and early
diagnosis
based on mass specrometry proteomics
(whose goal is to identify and quantify
proteins from biological samples)
SOURCES: human samples (fluids: blood,
CSF, urine and saliva. DNA (and
modifications), RNA, miRNA, proteins
(PTM)
3 PHASES IN THE
DEVELOPMENT OF A NEW ONE
DISCOVERY PHASE: proteomic
techniques are applied to blood or
CSF to identify candidates
VERIFICATION PHASE: quantify the
candidates to confirm differential
expression in blood/CSF from cases
vs controls
VALIDATION PHASE: considered for
further clinical evaluation
MRM-MS and
immunoassay
MRM-LC-MS/MS
LC-MS/MS with
fractionation
TYPES
DNA- BASED
BLOOD- BASED:
CSF- BASED
PROTEINS: 0.15-0.45 g/L in plasma,
proximal to the CNS (interacts with
brain, reflects its biochemical
changes), highly invasive, contáis
components form the blood and
CNS
MS, microarray, 2D gel
changes at
protein levels
are associated
with AD
basic biomarker:
albumin (biomarker
for blood brain
barrier BBB)
increase=
BBB damage
sPLA2 is a BBB factor
increase=
BBB damage
Visinin-like 1 increased after stroke
increase in tau/pTau= MCI to AD
increase in neurofilament proteins= neuronal damage
downgrade in FAB3, CHGA, B, Neurogranin
elevated S-100B, GFAP
related to Aβ
BACE1, sAPPα/sAPPβ, or Aβ oligomers
PROTEINS: 60-80 g/L in plasma,
blood is in contact with all cells,
easily accesible (non-invasive),
cost-time efficient, can be
separated into components
(plasma and serum)
MS, microarray, 2D gel
changes at
protein levels
are associated
with AD
downregulated Aβ (plasma biomarker)
upregulated ApoE (chromosome 19)
IL-1α, IL-6 (increase risk)
Clusterin: ilipoprotein that is part of amyloid plaques
increased α-1-antichymotrypsin: inflammatory
cascade and formation od amyloid fibrils
downregulated ADNP in early phase
DNA methylation studies.
Obtained from cells and
exosomes in plasma
miRNA: non-coding, players of
postranscriptional gene
modification
DETECTED BY: RT-PCR,
microarray and
sequencing, 2D gel