Normalization of Soluble CD163 Levels After Institution of Antiretroviral Therapy During Acute HIV Infection Tracks with Fewer Neurological Abnormalities

Background

Myeloid activation contributes to cognitive impairment in chronic human immunodeficiency virus (HIV) infection. We explored whether combination antiretroviral therapy (cART) initiation during acute HIV infection impacts CD163 shedding, a myeloid activation marker, and in turn, implications on the central nervous system (CNS).

Methods

We measured soluble CD163 (sCD163) levels in plasma and cerebrospinal fluid (CSF) by enzyme-linked immunosorbent assay in Thais who initiated cART during acute HIV infection (Fiebig stages I-IV). Examination of CNS involvement included neuropsychological testing and analysis of brain metabolites by magnetic resonance spectroscopy. Chronic HIV-infected or uninfected Thais served as controls.

Results

We examined 51 adults with acute HIV infection (Fiebig stages I-III; male sex, >90%; age, 31 years). sCD163 levels before and after cART in Fiebig stage I/II were comparable to those in uninfected controls (plasma levels, 97.9 and 93.6 ng/mL, respectively, vs 99.5 ng/mL; CSF levels, 6.7 and 6.4 ng/mL, respectively, vs 7.1 ng/mL). In Fiebig stage III, sCD163 levels were elevated before cART as compared to those in uninfected controls (plasma levels, 135 ng/mL; CSF levels, 10 ng/mL; P < .01 for both comparisons) before normalization after cART (plasma levels, 90.1 ng/mL; CSF levels, 6.5 ng/mL). Before cART, higher sCD163 levels during Fiebig stage III correlated with poor CNS measures (eg, decreased N-acetylaspartate levels), but paradoxically, during Fiebig stage I/II, this association was linked with favorable CNS outcomes (eg, higher neuropsychological test scores). After cART initiation, higher sCD163 levels during Fiebig stage III were associated with negative CNS indices (eg, worse neuropsychological test scores).

Conclusion

Initiation of cART early during acute HIV infection (ie, during Fiebig stage I/II) may decrease inflammation, preventing shedding of CD163, which in turn might lower the risk of brain injury.

Cenicriviroc inhibits trans-endothelial passage of monocytes and is associated with impaired E-selectin expression

Incidences of cardiovascular diseases (CVD) are high among virologically suppressed HIV-infected individuals. Monocyte activation and trafficking are key mechanisms in the evolution of CVD. We studied the ability of cenicriviroc (CVC), a dual C-C chemokine receptor type 2 (CCR2) and CCR5 antagonist, to influence the migration of monocytes from HIV-infected individuals on antiretroviral therapy (ART). Monocytes were derived from 23 ART-suppressed HIV-infected and 16 HIV-uninfected donors. In a trans-endothelial migration model, monocytes, and human aortic endothelial cells (HAoECs) were exposed to cenicriviroc and migrated monocytes, quantified. Expression of CCR2 and CCR5 on monocytes and adhesion molecules (E-selectin, ICAM-1, VCAM-1, PECAM-1, and CD99) on HAoECs were measured. The single antagonists, BMS-22 (CCR2), and maraviroc (CCR5), served as controls. When both HAoECs and monocytes together were exposed to the antagonists, cenicriviroc led to a greater decrease in monocyte migration compared to BMS-22 or vehicle in both HIV-infected and HIV-uninfected groups (P < 0.05), with maraviroc having no inhibitory effect. Cenicriviroc treatment of HAoECs alone decreased monocyte migration in the HIV-infected group when compared to vehicle (P < 0.01). Inhibition of migration was not evident when monocytes alone were exposed to cenicriviroc, BMS-22 or maraviroc. Incubation of HAoECs with cenicriviroc decreased E-selectin expression (P = 0.045) but had limited effects on the other adhesion molecules. Cenicriviroc inhibits monocyte trans-endothelial migration more effectively than single chemokine receptor blockade, which may be mediated via disruption of monocyte-endothelial tethering through reduced E-selectin expression. Cenicriviroc should be considered as a therapeutic intervention to reduce detrimental monocyte trafficking.

Comparative DNA Methylation Profiling Reveals an Immunoepigenetic Signature of HIV-related Cognitive Impairment

Monocytes/macrophages contribute to the neuropathogenesis of HIV-related cognitive impairment (CI); however, considerable gaps in our understanding of the precise mechanisms driving this relationship remain. Furthermore, whether a distinct biological profile associated with HIV-related CI resides in immune cell populations remains unknown. Here, we profiled DNA methylomes and transcriptomes of monocytes derived from HIV-infected individuals with and without CI using genome-wide DNA methylation and gene expression profiling. We identified 1,032 CI-associated differentially methylated loci in monocytes. These loci related to gene networks linked to the central nervous system (CNS) and interactions with HIV. Most (70.6%) of these loci exhibited higher DNA methylation states in the CI group and were preferentially distributed over gene bodies and intergenic regions of the genome. CI-associated DNA methylation states at 12 CpG sites associated with neuropsychological testing performance scores. CI-associated DNA methylation also associated with gene expression differences including CNS genes CSRNP1 (P = 0.017), DISC1 (P = 0.012), and NR4A2 (P = 0.005); and a gene known to relate to HIV viremia, THBS1 (P = 0.003). This discovery cohort data unveils cell type-specific DNA methylation patterns related to HIV-associated CI and provide an immunoepigenetic DNA methylation “signature” potentially useful for corroborating clinical assessments, informing pathogenic mechanisms, and revealing new therapeutic targets against CI.

Elevation of Non-Classical (CD14+/lowCD16++) Monocytes Is Associated with Increased Albuminuria and Urine TGF-β1 in HIV-Infected Individuals on Stable Antiretroviral Therapy

OBJECTIVE

High rates of albuminuria are observed among HIV-infected individuals on stable antiretroviral therapy (ART). Though pro-inflammatory and pro-fibrotic responses are described as components of albuminuria in the general population, it is unclear how these responses are associated to albuminuria in ART-treated chronic HIV. We investigated the relationship of monocyte subsets and urine inflammatory and fibrotic biomarkers to albuminuria in ART-treated HIV-infected participants.

DESIGN AND METHODS

Cross-sectional analyses were performed on Hawaii Aging with HIV-cardiovascular disease study cohort participants who were required at entry to be ≥40 years old and on ART ≥3 months. Monocyte subpopulations were determined in banked peripheral blood mononuclear cells (PBMC) using multi-parametric flow-cytometry. Entry random urine samples were assessed for albumin-to-creatinine ratios (UACR). Urine samples were measured for inflammatory and fibrotic biomarkers using Luminex technology.

RESULTS

Among 96 HIV-infected subjects with measured UACR (87% male, 59% Caucasian, and 89% undetectable HIV RNA with median CD4 of 495.5 cells/μL), 18 patients (19%) had albuminuria. Non-classical (CD14low/+CD16++) monocytes were significantly elevated in subjects with albuminuria (p = 0.034) and were correlated to UACR (r = 0.238, p = 0.019). Elevated non-classical monocyte counts were significant predictors of worsening albuminuria, independent of traditional- and ART-associated risk factors (β = 0.539, p = 0.007). Urine TGF-β1 and collagen-IV were significantly higher in albuminuric compared to non-albuminuric participants (TGF-β1; p = 0.039 and collagen-IV; p = 0.042). Urine TGF-β1 was significantly correlated with non-classical monocyte counts (r = 0.464, p = 0.017).

CONCLUSION

Alterations in monocyte subpopulations and urine pro-fibrotic factors may play a role in kidney dysfunction during chronic HIV infection and warrants further study.

Loss of CCR2 expressing non-classical monocytes are associated with cognitive impairment in antiretroviral therapy-naïve HIV-infected Thais

HIV DNA in monocytes has been linked to HIV-associated neurocognitive disorders (HAND), however, characterization of monocyte subsets associated with HAND remains unclear. We completed a prospective study of antiretroviral therapy-naïve, HIV-infected Thais, with varying degrees of cognitive impairment, compared to HIV-uninfected controls. Monocyte subsets' CCR2, CCR5 and CD163 expression were profiled and inflammatory markers in plasma and cerebrospinal fluid (CSF), measured. Lower numbers of CCR2(+)non-classical monocytes were associated with worse neuropsychological test performance (r=0.43, p=0.024). CCR2(+)non-classical monocyte count inversely correlated with CSF neopterin (r=-0.43, p=0.035) and plasma TNF-α levels (r=-0.40, p=0.041). These data benchmark CCR2(+)non-classical monocytes as an independent index of cognitive impairment.

Dual CCR2/CCR5 antagonism by Cenicriviroc efficiently inhibits both MCP-1 and RANTES induced chemokine receptor internalization in murine pro-inflammatory monocytes (CCR6P.221)

Persistent immune activation, driven in part by monocytes and macrophages (MO), has been implicated in HIV-associated comorbidities and progressive liver disease. Binding of chemokines MCP-1 and RANTES to their respective chemokine receptors (CKR), CCR2 and CCR5, selectively regulates the migration of MO. Cenicriviroc (CVC), an oral, dual CCR2 and CCR5 antagonist, has completed Phase 2b development in HIV and is undergoing Phase 2b evaluation in subjects with non-alcoholic steatohepatitis (NASH) and liver fibrosis. We assessed CVC receptor occupancy, measured by inhibition of MCP-1 and RANTES induced CKR internalization, compared to single antagonists BMS-22 (CCR2) and Maraviroc (MVC; CCR5) in pro-inflammatory (CD11c+F4/80+Ly6c+) MO in male BALB/c mice (n=6) by flow cytometry and quantified using Molecules of Equivalent Soluble Fluorochrome microspheres. CVC significantly reduced both MCP-1 induced internalization of CCR2 (p&lt;0.01) and RANTES induced internalization of CCR5 (p&lt;0.01). Doses of 0.25-1μM achieved &gt;90% CCR2 and CCR5 occupancy by CVC compared to 49% CCR2 occupancy by BMS-22 and 69% CCR5 occupancy by MVC in blood pro-inflammatory MO. Doses of 0.02-1μM achieved &gt;85% CCR2 and CCR5 occupancy by CVC compared to 72% CCR2 occupancy by BMS-22 and 73% CCR5 occupancy by MVC in spleen pro-inflammatory MO. These data suggest that CVC leads to efficient CCR2 and CCR5 target coverage in blood and tissues with effective doses lower than that of respective single CKR antagonists.

Anti-tat Hutat2:Fc mediated protection against tat-induced neurotoxicity and HIV-1 replication in human monocyte-derived macrophages

BACKGROUND

HIV-1 Tat is essential for HIV replication and is also a well-known neurotoxic factor causing HIV-associated neurocognitive disorder (HAND). Currently, combined antiretroviral therapy targeting HIV reverse transcriptase or protease cannot prevent the production of early viral proteins, especially Tat, once HIV infection has been established. HIV-infected macrophages and glial cells in the brain still release Tat into the extracellular space where it can exert direct and indirect neurotoxicity. Therefore, stable production of anti-Tat antibodies in the brain would neutralize HIV-1 Tat and thus provide an effective approach to protect neurons.

METHODS

We constructed a humanized anti-Tat Hutat2:Fc fusion protein with the goal of antagonizing HIV-1 Tat and delivered the gene into cell lines and primary human monocyte-derived macrophages (hMDM) by an HIV-based lentiviral vector. The function of the anti-Tat Hutat2:Fc fusion protein and the potential side effects of lentiviral vector-mediated gene transfer were evaluated in vitro.

RESULTS

Our study demonstrated that HIV-1-based lentiviral vector-mediated gene transduction resulted in a high-level, stable expression of anti-HIV-1 Tat Hutat2:Fc in human neuronal and monocytic cell lines, as well as in primary hMDM. Hutat2:Fc was detectable in both cells and supernatants and continued to accumulate to high levels within the supernatant. Hutat2:Fc protected mouse cortical neurons against HIV-1 Tat86-induced neurotoxicity. In addition, both secreted Hutat2:Fc and transduced hMDM led to reducing HIV-1BaL viral replication in human macrophages. Moreover, lentiviral vector-based gene introduction did not result in any significant changes in cytomorphology and cell viability. Although the expression of IL8, STAT1, and IDO1 genes was up-regulated in transduced hMDM, such alternation in gene expression did not affect the neuroprotective effect of Hutat2:Fc.

CONCLUSIONS

Our study demonstrated that lentivirus-mediated gene transfer could efficiently deliver the Hutat2:Fc gene into primary hMDM and does not lead to any significant changes in hMDM immune-activation. The neuroprotective and HIV-1 suppressive effects produced by Hutat2:Fc were comparable to that of a full-length anti-Tat antibody. This study provides the foundation and insights for future research on the potential use of Hutat2:Fc as a novel gene therapy approach for HAND through utilizing monocytes/macrophages, which naturally cross the blood-brain barrier, for gene delivery.

CD16+ expressing monocyte subsets and CD14+ HIV DNA levels predict HIV-associated neurocognitive disorders (HAND) in treatment-naïve HIV infected Thai subjects (P3043)

Since the advent of anti-retroviral (ARV) therapy, HIV-dementia has significantly declined, however, milder forms of HIV-associated Neurocognitive Disorder (HAND) remain highly prevalent. HIV DNA reservoirs in CD14+ Monocytes (MO) have been associated with cognitive impairment. However, the role of MO subsets in the pathogenesis of HAND over time remains poorly characterized. We sought to analyze HIV DNA content and MO phenotypic properties in relation to cognitive impairment through a prospective study of 30 ARV therapy-naïve individuals enrolled by HIV DNA reservoir levels with subsequent cognitive characterization as normal (n=17), Asymptomatic Neurocognitive Impairment (n=6), Mild Neurocognitive Disorder (MND) (n=2), HIV-associated dementia (HAD) (n=5) and 44 HIV- matched controls. HIV DNA was extracted from CD14+ cells and quantified by PCR. MO subsets and cell surface chemokine receptors were measured by flow cytometry using an extensive panel to exclude non-MO. Our preliminary findings show that among 4 MO subsets, there was a statistically significant decline in frequency of CD14highCD16+ (p&lt;0.001) and an increase in CD14lowCD16- (p&lt;0.001) in HIV+ compared to HIV- individuals. Remarkably, we found that CD14lowCD16+ MO frequency was lower in cognitively impaired individuals (p&lt;0.05) and frequency of CCR2+ and CCR5+ expressing MO was higher in symptomatic (MND and HAD) cognitively impaired HIV+ individuals (p&lt;0.05, p&lt;0.05).

Rapid Galectin-9 release occurs following HIV-1 acquisition in acute HIV-1 infection (P6165)

Despite successes with antiretroviral therapy, HIV infection continues to be a significant health burden with patients remaining at risk of non-AIDS defining events. The earliest immunological responses induced during HIV infection are key events in the control of HIV disease progression. Soluble biomarkers may aid in understanding HIV-immunopathogenesis, inflammation and prophylactic vaccine design. Galectin-9 (Gal-9) is a bidirectional immune regulator that promotes tissue inflammation and cell death but induces immune tolerance in part through engagement with the Tim-3 receptor. We measured circulating levels of Gal-9 in the plasma of 10 acute HIV-infected subjects at multiple time points over a 42-day period, before and after detectable HIV RNA. Plasma HIV RNA levels increased rapidly in all subjects. We found that Gal-9 levels rose with the first median elevation time of 5 days after detectable viremia and a median peak of 57.4 pg/ml. Overall Gal-9 levels generally tracked with viremia. In vitro, recombinant Gal-9 significantly increased IFN-γ production by CD8+ T cells compared to untreated cells (0.02% vs 1.2%) in cultures from early HIV-infected subjects and this was reversed by α-lactose blockade. Our findings reveal that Gal-9 is a novel plasma factor that is rapidly elevated during the first wave of the cytokine storm after HIV emergence and may have important roles in CD4+ T cell loss or the response to tissue damage.

Novel method for next generation sequencing of KIR by Roche 454 (P3383)

Natural Killer cells are regulated by the polymorphic Killer Ig-like Receptor family. KIR genotype and expression has been associated with HIV-1 disease progression. We developed a high-throughput method to characterize both DNA genotype and RNA expression of KIR using a novel 454 sequencing method (Roche), for study of HIV and innate immunity. This method uses a 299bp and 395bp amplicon to distinguish and assign long - and short-tailed KIR. These amplicons, from motifs common to 3’ UTR of known KIR genes, amplify both KIR DNA and mRNA. We developed a custom bioinformatics pipeline to analyze 454 sequence reads and it compares each sequence (average 3000 reads per specimen) to a reference alignment of KIR genes via the BLAT algorithm. Using this method, we characterized KIR in a cohort of 700 treatment-naïve adults in early HIV-1 disease. Initial results indicate that our KIR DNA 454 sequencing data agree with KIR DNA genotyping results from mass spectrometry-based typing as well as sequence-specific oligonucleotide typing. KIR3DL1 expression on NK cells by flow cytometry shows 80% agreement with KIR mRNA expression from PBMCs by 454. The use of mRNA- and DNA-based next generation sequencing for human immune receptor genes, such as KIR, will accelerate genetic association and functional genetic studies of diseases of the immune system.