Immunometabolic regulation in natural HIV-1 control

The elite controllers (EC) are a rare group of people living with HIV-1 infection (PLHIV) that can control viral replication in the absence of antiretroviral therapy for a prolonged time. The mechanisms behind elite control phenotype leading to viral suppression are not fully elucidated. It has also become clear that molecules function in complex and interconnected networks shaping the phenotype of a cell, tissue, or organism. The advancements made in high- throughput technologies and in computational methods enable the investigation of a large set of molecules simultaneously allowing to fingerprint the cross-talks and dynamics of these molecules. The work presented in this thesis aimed to unravel the immuno-metabolic regulation in PLHIVEC using a data-driven approach where untargeted metabolomics, proteomics and microbiome profiling were applied in combination with targeted immunological and other assays. We observed that PLHIVEC had a distinct plasma and fecal metabolic signature compared to treatment-naïve HIV-1-positive viremic progressors (PLHIVVP) and HIV- negative individuals (HC). Low-level inflammation and antioxidant defense mechanisms at physiological levels seen in plasma and blood cells, together with increased fecal levels of dipeptides and the bacterial genus Prevotella are proposed to be important factors involved in natural control of HIV-1. Furthermore, a unique signature of chemokine receptor expression on immune cells and a specific proteomic profile of CD4+ T cells indicative of a modulated energy metabolism may also play a role in EC phenotype. Altogether these features are suggested to create an unfavorable environment for HIV-1 replication and thus contribute to natural control of the virus

Systemic Inflammation and the Increased Risk of Inflamm-Aging and Age-Associated Diseases in People Living With HIV on Long Term Suppressive Antiretroviral Therapy.

The ART program in low- and middle-income countries (LMIC) like India, follows a public health approach with a standardized regimen for all people living with HIV (PLHIV). Based on the evidence from high-income countries (HIC), the risk of an enhanced, and accentuated onset of premature-aging or age-related diseases has been observed in PLHIV. However, very limited data is available on residual inflammation and immune activation in the populations who are on first-generation anti-HIV drugs like zidovudine and lamivudine that have more toxic side effects. Therefore, the aim of the present study was to evaluate the levels of systemic inflammation and understand the risk of age-associated diseases in PLHIV on long-term suppressive ART using a large number of biomarkers of inflammation and immune activation. Blood samples were obtained from therapy naïve PLHIV (Pre-ART, = 43), PLHIV on ART for >5 years (ART, = 53), and HIV-negative healthy controls (HIVNC, = 41). Samples were analyzed for 92 markers of inflammation, sCD14, sCD163, and telomere length. Several statistical tests were performed to compare the groups under study. Multivariate linear regression was used to investigate the associations. Despite a median duration of 8 years of successful ART, sCD14 ( < 0.001) and sCD163 ( = 0.04) levels continued to be significantly elevated in ART group as compared to HIVNC. Eleven inflammatory markers, including 4E-BP1, ADA, CCL23, CD5, CD8A, CST5, MMP1, NT3, SLAMF1, TRAIL, and TRANCE, were found to be significantly different ( < 0.05) between the groups. Many of these markers are associated with age-related co-morbidities including cardiovascular disease, neurocognitive decline and some of these markers are being reported for the first time in the context of HIV-induced inflammation. Linear regression analysis showed a significant negative association between HIV-1-positivity and telomere length ( < 0.0001). In ART-group CXCL1 ( = 0.048) and TGF-α ( = 0.026) showed a significant association with the increased telomere length and IL-10RA was significantly associated with decreased telomere length ( = 0.042). This observation warrants further mechanistic studies to generate evidence to highlight the need for enhanced treatment monitoring and special interventions in HIV-infected individuals

Immune Checkpoints as the Immune System Regulators and Potential Biomarkers in HIV-1 Infection

Immune checkpoints are several co-stimulatory and inhibitory pathways that regulate T cell immune responses. Most of the discoveries about immune checkpoints were made in cancer research where inhibitory immune checkpoints cause immune exhaustion and down-regulate anti-tumor responses. In addition to cancer, immune checkpoints are exploited in chronic infectious diseases. In human immunodeficiency virus (HIV) infection, the immune checkpoint molecule called programmed cell death protein 1 (PD-1) has been determined as being a major regulatory factor for T cell exhaustion. Recent studies with antibodies blocking either PD-1 ligand 1 (PD-L1) or PD-1 show not only promising results in the enhancement of HIV-specific immune responses but even in reducing the latent HIV reservoir. Apart from the therapeutic target for a functional cure of HIV-1, immune checkpoint molecules might be used as biomarkers for monitoring disease progression and therapeutic response. In this review, we will summarize and discuss the inhibitory immune checkpoint molecules PD-1, cytotoxic T-lymphocyte-associated protein 4 (CTLA4), lymphocyte-activation gene 3 (LAG3), and T cell immunoglobulin and mucin-domain-containing-3 (TIM3) as well as the co-stimulatory molecules CD40L and CD70, including their role in immunity, with a particular focus on HIV infection, and being potential targets for a functional HIV cure

Immune Checkpoints as the Immune System Regulators and Potential Biomarkers in HIV-1 Infection

Immune checkpoints are several co-stimulatory and inhibitory pathways that regulate T cell immune responses. Most of the discoveries about immune checkpoints were made in cancer research where inhibitory immune checkpoints cause immune exhaustion and down-regulate anti-tumor responses. In addition to cancer, immune checkpoints are exploited in chronic infectious diseases. In human immunodeficiency virus (HIV) infection, the immune checkpoint molecule called programmed cell death protein 1 (PD-1) has been determined as being a major regulatory factor for T cell exhaustion. Recent studies with antibodies blocking either PD-1 ligand 1 (PD-L1) or PD-1 show not only promising results in the enhancement of HIV-specific immune responses but even in reducing the latent HIV reservoir. Apart from the therapeutic target for a functional cure of HIV-1, immune checkpoint molecules might be used as biomarkers for monitoring disease progression and therapeutic response. In this review, we will summarize and discuss the inhibitory immune checkpoint molecules PD-1, cytotoxic T-lymphocyte-associated protein 4 (CTLA4), lymphocyte-activation gene 3 (LAG3), and T cell immunoglobulin and mucin-domain-containing-3 (TIM3) as well as the co-stimulatory molecules CD40L and CD70, including their role in immunity, with a particular focus on HIV infection, and being potential targets for a functional HIV cure

Transcriptomics and Targeted Proteomics Analysis to Gain Insights Into the Immune-control Mechanisms of HIV-1 Infected Elite Controllers

A small subset of HIV-1 infected individuals, the "Elite Controllers" (EC), can control viral replication and restrain progression to immunodeficiency without antiretroviral therapy (ART). In this study, a cross-sectional transcriptomics and targeted proteomics analysis were performed in a well-defined Swedish cohort of untreated EC (n = 19), treatment naive patients with viremia (VP, n = 32) and HIV-1-negative healthy controls (HC, n = 23). The blood transcriptome identified 151 protein-coding genes that were differentially expressed (DE) in VP compared to EC. Genes like CXCR6 and SIGLEC1were downregulated in EC compared to VP. A definite distinction in gene expression between males and females among all patient-groups were observed. The gene expression profile between female EC and the healthy females was similar but did differ between male EC and healthy males. At targeted proteomics analysis, 90% (29/32) of VPs clustered together while EC and HC clustered separately from VP. Among the soluble factors, 33 were distinctive to be statistically significant (False discovery rate = 0.02). Cell surface receptor signaling pathway, programmed cell death, response to cytokine and cytokine-mediated signaling seem to synergistically play an essential role in HIV-1 control in EC.QC 20180316</p

Peripheral blood CD4+CCR6+ compartment differentiates HIV-1 infected or seropositive elite controllers from long-term successfully treated individuals

Svensson Akusjärvi S, Krishnan S, Jütte B, et al. Peripheral blood CD4+CCR6+ compartment differentiates HIV-1 infected or seropositive elite controllers from long-term successfully treated individuals. Communications Biology. 2022;5(1): 357.**Abstract** HIV-1 infection induces a chronic inflammatory environment not restored by suppressive antiretroviral therapy (ART). As of today, the effect of viral suppression and immune reconstitution in people living with HIV-1 (PLWH) has been well described but not completely understood. Herein, we show how PLWH who naturally control the virus (PLWHEC) have a reduced proportion of CD4+CCR6+and CD8+CCR6+cells compared to PLWH on suppressive ART (PLWHART) and HIV-1 negative controls (HC). Expression of CCR2 was reduced on both CD4+, CD8+and classical monocytes in PLWHECcompared to PLWHARTand HC. Longer suppressive therapy, measured in the same patients, decreased number of cells expressing CCR2 on all monocytic cell populations while expression on CD8+T cells increased. Furthermore, the CD4+CCR6+/CCR6−cells exhibited a unique proteomic profile with a modulated energy metabolism in PLWHECcompared to PLWHARTindependent of CCR6 status. The CD4+CCR6+cells also showed an enrichment in proteins involved in apoptosis and p53 signalling in PLWHECcompared to PLWHART, indicative of increased sensitivity towards cell death mechanisms. Collectively, this data shows how PLWHEChave a unique chemokine receptor profile that may aid in facilitating natural control of HIV-1 infection