HIV-1-Associated Neurocognitive Disorders: Is HLA-C Binding Stability to β2-Microglobulin a Missing Piece of the Pathogenetic Puzzle?

CD3+CD56+ and CD3-CD56+ lymphocytes in the cerebrospinal fluid of persons with HIV-1 subtypes B and C

The transactivator of transcription (Tat) is a HIV regulatory protein which promotes viral replication and chemotaxis. HIV-1 shows extensive genetic diversity, HIV-1 subtype C being the most dominant subtype in the world. Our hypothesis is the frequency of CSF CD3+CD56+ and CD3-CD56dim is reduced in HIV-1C compared to HIV-1B due to the Tat C30S31 substitution in HIV-1C. 34 CSF and paired blood samples (PWH, n = 20; PWoH, n = 14) were studied. In PWH, the percentage of CD3+CD56+ was higher in CSF than in blood (p < 0.001), comparable in both compartments in PWoH (p = 0.20). The proportion of CD3-CD56dim in CSF in PWH was higher than PWoH (p = 0.008). There was no subtype differences. These results showed CNS compartmentalization of NKT cell response in PWH.

Increased Prevalence of Unstable HLA-C Variants in HIV-1 Rapid-Progressor Patients

HIV-1 infection in the absence of treatment results in progression toward AIDS. Host genetic factors play a role in HIV-1 pathogenesis, but complete knowledge is not yet available. Since less-expressed HLA-C variants are associated with poor HIV-1 control and unstable HLA-C variants are associated with higher HIV-1 infectivity, we investigated whether there was a correlation between the different stages of HIV-1 progression and the presence of specific HLA-C allotypes. HLA-C genotyping was performed using allele-specific PCR by analyzing a treatment-naïve cohort of 96 HIV-1-infected patients from multicentric cohorts in the USA, Canada, and Brazil. HIV-1-positive subjects were classified according to their different disease progression status as progressors (Ps, n = 48), long-term non-progressors (LTNPs, n = 37), and elite controllers (ECs, n = 11). HLA-C variants were classified as stable or unstable according to their binding stability to β2-microglobulin/peptide complex. Our results showed a significant correlation between rapid progression to AIDS and the presence of two or one unstable HLA-C variants (p-value: 0.0078, p-value: 0.0143, respectively). These findings strongly suggest a link between unstable HLA-C variants both at genotype and at allele levels and rapid progression to AIDS. This work provides further insights into the impact of host genetic factors on AIDS progression.

Epigenetic clock analysis in methamphetamine dependence

Methamphetamine (MA) is used worldwide and causes serious public health and social problems. MA affects the central nervous, cardiac, and immune systems, which causes neuropsychiatric and cardiovascular diseases and infection. Epigenetic changes, including DNA methylation (DNAm), are associated with various clinical phenotypes of MA abuse. DNAm is related to biological aging and health risks; hence, we aimed to assess the changes in biological aging in MA dependence using the DNAm age and DNA methylation-based telomere length (DNAmTL). We used five measures of DNAm age (HorvathAge, HannumAge, SkinBloodAge, PhenoAge, and GrimAge), DNAmTL, and DNAm-based age-predictive factors (plasma proteins and blood cell composition). We compared patients with MA dependence and healthy controls (n = 24 each) using the DNAm profiles obtained from whole-blood samples. Patients with MA dependence showed significant acceleration in PhenoAge and GrimAge, as well as a trend for significant acceleration in DNAmTL. Following adjustment for confounding factors, MA dependence was significantly associated with accelerations in PhenoAge, GrimAge, and DNAmTL, as well as alterations in DNAm-based age-predictive factors (beta-2-microglobulin, granulocytes, and naive cluster of differentiation 4+ T cells). Our results suggested an acceleration of biological aging and specific changes in the DNAm of age- predictive factors in MA dependence.

Itaconate alleviates β2-microglobulin-induced cognitive impairment by enhancing the hippocampal amino-β-carboxymuconate-semialdehyde-decarboxylase/picolinic acid pathway

β₂-microglobulin (B₂M) has been established to impair cognitive function. However, no treatment is currently available for B₂M-induced cognitive dysfunction. Itaconate is a tricarboxylic acid (TCA) cycle intermediate that exerts neuroprotective effects in several neurological diseases. The amino-β-carboxymuconate-semialdehyde-decarboxylase (ACMSD)/picolinic acid (PIC) pathway is a crucial neuroprotective branch in the kynurenine pathway (KP). The present study sought to investigate whether Itaconate attenuates B₂M-induced cognitive impairment and examine the mediatory role of the hippocampal ACMSD/PIC pathway. We demonstrated that 4-Octyl Itaconate (OI, an itaconate derivative) significantly alleviated B₂M-induced cognitive dysfunction and hippocampal neurogenesis impairment. OI treatment also increased the expression of ACMSD, elevated the concentration of PIC, and decreased the level of 3-HAA in the hippocampus of B₂M-exposed rats. Furthermore, inhibition of ACMSD by TES-991 significantly abolished the protections of Itaconate against B₂M-induced cognitive impairment and neurogenesis deficits. Exogenous PIC supplementation in hippocampus also improved cognitive performance and hippocampal neurogenesis in B₂M-exposed rats. These findings demonstrated that Itaconate alleviates B₂M-induced cognitive impairment by upregulation of the hippocampal ACMSD/PIC pathway. This is the first study to document Itaconate as a promising therapeutic agent to ameliorate cognitive impairment. Moreover, the mechanistic insights into the ACMSD/PIC pathway improve our understanding of it as a potential therapeutic target for neurological diseases beyond B₂M-associated neurocognitive disorders.

Soluble CD14 is subtype-dependent in serum but not in cerebrospinal fluid in people with HIV

Monocytes and macrophages activation are crucial in human immunodeficiency virus (HIV) central nervous system (CNS) infection and HIV associated neurocognitive disorders (HAND) pathogenesis. The soluble form of CD14 (sCD14) is a marker of monocyte activation. We hypothesized that sCD14 levels would be lower in people with HIV-1 subtype C (HIV-1C) than in HIV-1B owing to a variant Tat cysteine dimotif (C30S31) with reduced chemotactic activity. A total of 68 paired cerebrospinal fluid (CSF) and blood samples from people with HIV (PWH); 27 samples of the HIV-1B subtype and 40 of the non-B HIV-1 subtypes (including 26,HIV-1C), and 18 HIV-negative controls were included. sCD14 levels were quantified using a high-sensitivity enzyme-linked immunosorbent assay. sCD14 increase in serum, but not in CSF, was higher in samples from HIV-1B than HIV-1C (p = 0.002; Cohen's d, 0.7). CSF or serum sCD14 values were not correlated with global deficit score or specific cognitive domains. The impact of HIV-1 on monocyte stimulation biomarkers evaluated by sCD14 in serum was subtype-dependent, higher in HIV-1B than HIV-1C, consistent with reduced chemotactic activity as hypothesized.

Main lymphocyte subpopulations in cerebrospinal fluid and peripheral blood in HIV-1 subtypes C and B

HIV-1 subtype C (HIV-1C) shows reduced Tat protein chemoattractant activity compared with HIV-1B. The impact of HIV-1C Tat on the chemotaxis of the main lymphocyte subpopulations in the cerebrospinal fluid (CSF) and the peripheral blood (PB) is unclear. We hypothesized that there would be a lower frequency of specific lymphocyte subpopulations CD3⁺ or CD19⁺ in CSF in HIV-1C than in HIV-1B. The objectives were to detect the differences in the proportions of main lymphocyte subpopulations in CSF and PB, between people with HIV (PWH) and HIV-1-uninfected volunteers (PWoH) and in HIV-1B and HIV-1C. Lymphocyte immunophenotyping was studied in CSF and paired PB samples of PWH (n = 22) and PWoH (n = 14). Lymphocytes were analyzed within the CD45⁺ gated region. The proportions of CSF CD3⁺CD4⁺, CD3⁺CD8⁺, and CD3^-CD19⁺ lymphocytes in CSF were comparable in HIV-1B and C. There was an increase in the proportion of CD3⁺CD8⁺ cells and a decrease in CD3⁺CD4⁺ T cells (ps = 0.016) in the CSF samples of the PWH compared with the PWoH group. In the PWH group, both CD3⁺CD4⁺ and CD3⁺CD8⁺ lymphocytes were significantly higher in the CSF than in the PB (p = 0.047 and 0.005). The proportion of CD3⁺CD4⁺ was lower and that of CD3⁺CD8⁺ was higher in the CSF samples of the aviremic group than that of HIV-negative control (p = 0.0008 and < 0.0001, respectively). HIV-1C Tat substitution (C30S) did not interfere with the CNS migration of the main lymphocyte subpopulations. This is the first study to evaluate these lymphocytes in CSF and PB of HIV-1C compared with HIV-1B.

Distribution characteristics of serum β2-microglobulin between viral and bacterial lower respiratory tract infections: a retrospective study

Background

Lower respiratory tract infection (LRTI) is one of the leading cause of death in children under 5 years old around the world between 1980 and 2016. Distinguishing between viral and bacterial infection is challenging when children suffered from LRTI in the absence of pathogen detection. The aim of our study is to analyze the difference of serum β2-microglobulin (β2-MG) between viral LRTI and bacterial LRTI in children.

Methods

This retrospective study included children with LRTI caused by a single pathogen from Yancheng Third People’s Hospital, Yancheng, China, between January 1, 2016 and December 31, 2019. Participants were divided into the younger group (1 year old ≤ age < 3 years old) and the older group (3 years old ≤ age < 5 years old) for subgroup analysis.

Results

A total of 475 children with LRTI caused by common respiratory pathogens were identified. In the younger group as well as the older group, the serum level of β2-MG in respiratory syncytial virus, influenza A virus and influenza B virus groups were significantly increased compared to that in the Mycoplasma pneumoniae group. Compared with Streptococcus pneumoniae infection group, the serum β2-MG level of respiratory syncytial virus, influenza A virus and influenza B virus groups were significantly higher in children between 1 and 3 years old.

Conclusions

The serum β2-MG may distinguish viral infection from bacterial infection in children with LRTI.