Genomics Links Inflammation With Neurocognitive Impairment in Children Living With Human Immunodeficiency Virus Type-1.

BACKGROUND: We identified host single-nucleotide variants (SNVs) associated with neurocognitive impairment (NCI) in perinatally HIV-infected (PHIV) children. METHODS: Whole-exome sequencing (WES) was performed on 217 PHIV with cognitive score for age (CSA) < 70 and 247 CSA ≥ 70 (discovery cohort [DC]). SNVs identified in DC were evaluated in 2 validation cohorts (VC). Logistic regression was used to estimate adjusted odds ratios (ORs) for NCI. A human microglia NLRP3 inflammasome assay characterized the role of identified genes. RESULTS: Twenty-nine SNVs in 24 genes reaching P ≤ .002 and OR ≥ 1.5 comparing CSA < 70 to CSA ≥ 70 were identified in the DC, of which 3 SNVs were identified in VCs for further study. Combining the 3 cohorts, SNV in CCRL2 (rs3204849) was associated with decreased odds of NCI (P < .0001); RETREG1/FAM134B (rs61733811) and YWHAH (rs73884247) were associated with increased risk of NCI (P < .0001 and P < .001, respectively). Knockdown of CCRL2 led to decreased microglial release of IL-1ß following exposure to ssRNA40 while knockdown of RETREG1 and YWHAH resulted in increased IL-1ß release. CONCLUSIONS: Using WES and 2 VCs, and gene silencing of microglia we identified 3 genetic variants associated with NCI and inflammation in HIV-infected children.

SMAC Mimetics Induce Autophagy-Dependent Apoptosis of HIV-1-Infected Resting Memory CD4+ T Cells.

Long-lived resting memory CD4+ T cells (TCM) are a major reservoir of latent HIV infection. We hypothesized that latent HIV-TCM cells are maintained by aberrant expression of cell survival factors, including XIAP, BIRC2/cIAP1, and beclin-1. DIABLO/SMAC mimetics are therapeutic agents that compromise cell survival by hijacking host apoptotic machinery. We found that DIABLO/SMAC mimetics (birinapant, GDC-0152, and embelin) selectively kill HIV-TCM without increasing virus production or targeting uninfected TCM. Treatment of HIV-TCM with DIABLO/SMAC mimetics promoted XIAP and BIRC2 degradation, which triggered autophagy and the formation of a cell death complex consisting of pro-apoptotic (FADD, RIPK1, RIPK3, and caspase 8) and autophagy (ATG5, ATG7, and SQSTM1) proteins. Genetic or pharmacological inhibition of autophagy induction, but not autophagy-mediated degradation, abrogated this interaction and subsequent cell death. Our findings identify a mechanism whereby DIABLO/SMAC mimetics exploit autophagy and apoptotic machinery to selectively induce killing of HIV-TCM without viral reactivation while sparing uninfected cells.

Killer Cell Immunoglobulin-Like Receptor Alleles Alter HIV Disease in Children.

BACKGROUND: HLA class I molecules are ligands for killer cell immunoglobin like receptors (KIR) that control the antiviral response of natural killer (NK) cells. However, the effects of KIR and HLA (KIR/HLA) alleles on HIV disease of children have not been studied. METHODS: 993 antiretroviral naïve children with symptomatic HIV infection from PACTG protocols P152 and P300 were genotyped for KIR and HLA alleles using the Luminex platform. Linear regression was used to test the association between genotypes and baseline pre-ART HIV RNA, CD4+ lymphocyte count, and cognitive score, adjusting for age, race/ethnicity and study. The interaction between genetic markers and age was investigated. To account for multiple testing the false discovery rate (FDR) was controlled at 0.05. RESULTS: Children with the KIR2DS4*ALL FULL LENGTH (KIR2DS4*AFL) allele had higher CD4+ lymphocyte counts. Among children ≤2 years of age, the KIR2DS4*AFL was associated with lower plasma HIV RNA and higher cognitive index scores. KIR Cent2DS3/5_1 had lower CD4+ lymphocyte counts in children ≤2 years of age, while the presence of Tel1, Tel2DS4_2, Tel2DS4_4, Tel8, Tel2DS4_6 had higher CD4+ lymphocyte counts in all children. Presence of Cent2, Cent4 and Cent8 was associated with increased HIV RNA load in children ≤2 years. Presence of KIR3DL1+Bw4 was associated with higher CD4+ lymphocyte counts in all children. Among children >2 years old, KIR3DS1+Bw4-80I was associated with higher plasma HIV RNA, and Bw6/Bw6 was associated with lower plasma HIV RNA compared to children with KIR3DS1+Bw4-80I. CONCLUSIONS: Presented data show for the first time that specific KIR alleles independently or combined with HLA ligands are associated with HIV RNA and CD4+ lymphocyte counts in infected, antiretroviral naive children; and many of these effect estimates appear to be age dependent. These data support a role for specific KIR alleles in HIV pathogenesis in children.

HLA alleles are associated with altered risk for disease progression and central nervous system impairment of HIV-infected children.

OBJECTIVE: To examine the effects of human leukocyte antigen (HLA) alleles on HIV-1-related disease progression and central nervous system (CNS) impairment in children. DESIGN: Five hundred seventy-two HIV-1-infected children, identified as disease progressors or nonprogressors, were selected from PACTG P152 and P300 through a case-cohort sampling scheme. Study endpoints were HIV-1-related disease progression-free survival and time to CNS impairment. METHODS: DNA was genotyped for HLA alleles using a Luminex 100 platform. Weighted Kaplan-Meier methods, and Cox proportional hazards models were used to assess the effects of HLA alleles on study endpoints. RESULTS: Presence of the B-27 allele (n = 20) was associated with complete protection against disease progression and CNS impairment over the median follow-up of 26 months (P < 0.0001 for both). These findings held in multivariate analyses controlling for baseline covariates including race, gender, age, log HIV-1 RNA, CD4 lymphocyte count and percent, weight for age z score and treatment, and for other genotypes shown to affect HIV-1-related disease progression. Also, although the Cw-2 allele protected against disease progression [Hazard ratio (HR), 0.48; 95% confidence interval (CI): 0.28 to 0.81; P = 0.006], the A-24 allele was associated with more rapid CNS impairment (HR: 2.01; 95% CI: 1.04 to 3.88; P = 0.04). The HLA class II DQB1-2 allele was associated with a delayed disease progression (HR: 0.66; 95% CI: 0.47-0.92; P = 0.01) and CNS impairment (HR: 0.58; 95% CI: 0.36 to 0.93; P = 0.02). CONCLUSIONS: Presence of B-27, Cw-2, or DQB1-2 alleles was associated with delayed HIV-1 disease progression, while B-27, A-24, and DQB1-2 alleles were associated with altered progression to CNS impairment in children.

High T-cell response to human cytomegalovirus induces chemokine-mediated endothelial cell damage.

Human cytomegalovirus (CMV) infection has been linked to inflammatory diseases that involve vascular endothelial damage, including vascular disease and chronic transplant rejection. We previously reported that the host CD4(+) T-cell response to CMV antigen presented by endothelial cells can produce interferon-gamma and tumor necrosis factor-alpha at levels sufficient to drive induction of fractalkine, a key marker of inflammation, in endothelial cells. In this work, we report that donors with high frequencies of antigen-specific T cells to CMV (high responders) induce higher levels of activation-associated chemokines such as fractalkine, RANTES (regulated on activation, normal T cell expressed and secreted), and macrophage inflammatory protein-1beta, together with cell-adhesion markers in endothelial cells compared with donors with low levels of CMV-specific T cells (low responders). High-responder cultures had higher levels of leukocyte recruitment and adherence to the endothelial monolayers associated with progressive damage and loss of the endothelial cells. These processes that led to endothelial destruction only required viral antigen and did not require infectious virus. Our findings further support that CMV may represent one member of a class of persistent pathogens in which a high antigen-specific T-cell response defines an important risk factor for development of chronic inflammation and endothelial cell injury.

Human cytomegalovirus-specific CD4+-T-cell cytokine response induces fractalkine in endothelial cells.

Cytomegalovirus (CMV) infection has been linked to inflammation-related disease processes in the human host, including vascular diseases and chronic transplant rejection. The mechanisms through which CMV affects the pathogenesis of these diseases are for the most part unknown. To study the contributing role of the host immune response to CMV in these chronic inflammatory processes, we examined endothelial cell interactions with peripheral blood mononuclear cells (PBMC). Endothelial cultures were monitored for levels of fractalkine induction as a marker for initiating the host inflammatory response. Our results demonstrate that in the presence of CMV antigen PBMC from normal healthy CMV-seropositive donors produce soluble factors that induce fractalkine in endothelial cells. This was not observed in parallel assays with PBMC from seronegative donors. Examination of subset populations within the PBMC further revealed that CMV antigen-stimulated CD4(+) T cells were the source of the factors, gamma interferon and tumor necrosis factor alpha, driving fractalkine induction. Direct contact between CD4(+) cells and the endothelial monolayers is required for this fractalkine induction, where the endothelial cells appear to provide antigen presentation functions. These findings indicate that CMV may represent one member of a class of persistent pathogens where the antigen-specific T-cell response can result in the induction of fractalkine, leading to chronic inflammation and endothelial cell injury.