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A Proteomic Fingerprint of Cerebrospinal Fluids from Individuals with HIV-1-associated Dementia
W Rozek1, S Holloway1, M Ricardo-Dukelow1, L Melendez2, and Pawel Ciborowski*1
1Univ of Nebraska Med Ctr, Omaha, US and 2Specialized NeuroAIDS Prgm, San Juan, PR, US
Background: Mononuclear
phagocytes (MP) are vehicles for dissemination of persistent HIV-1 infection.
Targets include tissues of the lymphoreticular
system, lung, liver, and most commonly the brain. Indeed, neurotoxic
products released by these infected cells contribute to the neuropathogenesis
of HIV-1 infection, subsequently, leading to HIV-associated dementia (HAD).
Once started, HAD ultimately leads to death. The lack of appropriate biomarkers
that inform us about the progress of brain injury triggered by HIV-1 is the main
limitation of HAD treatment, thus, appropriate biomarkers for the disease are
desperately needed. The recent development of proteomics has opened new ways to
study viral-host interactions which may provide new insight into treatment and
disease monitoring.
Methods: We used 2D SDS-PAGE
DIGE platform for this proteomic study. DeCyder®
6.5 software was used to determine differentially expressed proteins. To
facilitate analysis of low abundant proteins, we removed the 6 most abundant
proteins: albumin, immunoglobulin (Ig) G, IgA, antitrypsin
inhibitor, haptoglobin, and transferrin
from 12 CSF samples—6 from demented and 6 from non-demented individuals. Proteins
were identified using LC-MS/MS peptide sequencing of trypsin
in-gel digested protein spots.
Results: In first experiment,
which included 6 samples (3 from HAD and 3 from non-HAD), we analyzed 223 spots
and identified 67 proteins. Several proteins were found in multiple spots
representing isoforms. Among identified proteins we
have found those which are differentially expressed: neuronal cell adhesion molecule (NrCAM), cystatin C, vit D binding protein, and clusterin,
which are subjected to further validation using Western blot analysis and a
separate cohort of CSF samples from 38 individuals (12 non-HAD, 12 mild
cognitive impairment, and 14 HAD). The second experiment, performed with 6 CSF
samples from a different cohort, showed 90 proteins whose differential
expression was statistically significant (p
<0.05). These proteins are currently being identified using LC-MS/MS.
Conclusions: Proteins currently
under investigation may reveal new pattern of biomarkers of HAD.
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