Identification of putative biomarkers for HIV-associated neurocognitive impairment in the CSF of HIV-infected patients under cART therapy determined by mass spectrometry

Abstract

We identified and measured proteins in the cerebral spinal fluid (CSF) involved in HIV-associated neurological disorders. Protein levels were determined by mass spectrometry (MS) in pooled CSF taken from three patient groups (human immunodeficiency virus (HIV)-1-infected patients that developed HIV-associated neurocognitive disorders (HANDs), HIV-1-infected patients without HAND, and healthy controls). Pools were generated from 10 patients each per group. CSF from individual patient groups were digested with trypsin and separately labeled using with isobaric tags for relative and absolute quantitation (iTRAQ). After combining all samples in one, peptides were extensively fractionated by offline two-dimensional separation and identified by tandem MS. One hundred and ninety three proteins were deemed to be interpretable for quantitation based on permutation tests with a 95 % confidence interval with a p value≤0.05. Using a cutoff of 1.5-fold for upregulation and 0.6 for downregulation, 16 proteins were differentially expressed in HIV+HAND (reporter p value ≤0.05) with seven of them previously described as HIV-interacting proteins: endoplasmin, mitochondrial damage mediator-BH3-interacting domanin death agonist, orosomucoid, apolipoprotein E, metalloproteinase inhibitor 2, peroxiredoxin-2, and the nuclear protein, ruvB-like 2. Several previously unidentified proteins with possible neurological implication in HIV patients include forming-binding protein 1, C-reactive protein, leukocyte-associated immunoglobulin receptor 1, renin receptor, mediator of RNA polymerase II transcription subunit 14, multimerin-2, alpha-N-acetylglucosaminidase, caldesmon, and cadherin EGF LAG G-type receptor. Our results suggest that not only a few but possibly a combination of biomarkers that are highly correlated can predict neurocognitive status in HIV-infected patients and might be involved in monocyte or macrophage activation.

HIV as a Cause of Immune Activation and Immunosenescence

“…In individuals on ART, minuscule amounts of residual virus may be sufficient to maintain a self-perpetuating inflammatory response [ 137 ]. High levels of macrophage activation markers, such as sCD163, sCD14, and CCL2 in cerebrospinal fluid and blood, together with inflammatory biomarkers, such as CRP, IL-6, TNF- α , IP-10, and neopterin, have been implicated in the development of HIV-associated neurocognitive disorders (HAND) [ 139 , 140 ]. This is similar to what has been observed in the elderly, where inflammatory markers, particularly IL-6 and CRP, have been linked to cognitive decline and an increased risk of dementia [ 141 ].…”

Variability in C-reactive protein is associated with cognitive impairment in women living with and without HIV: a longitudinal study

“…In neuroimaging studies for example, plasma and CSF inflammatory biomarkers are strongly associated with adverse alterations in brain structure and function (Ances and Hammoud, 2014; Anderson et al , 2015a; Anderson et al , 2015b; Bora et al , 2014). The state of the science is primarily based on largely male-dominant samples and cross-sectional studies.…”

Proteomics, biomarkers, and HIV‐1: A current perspective

“…For plasma/serum it is not, even if the remaining amount of proteins after immunodepletion is low because plasma usually is available in large quantities. In the case of CSF, it may be impossible to perform full proteomic analysis with samples from individual subjects without sample pooling [87], however, final outcome showed limited success.…”