Selection of biomarkers for HIV-1 latency by integrated analysis

Host variation in type I interferon signaling genes (MX1), C-C chemokine receptor type 5 gene, and major histocompatibility complex class I alleles in treated HIV+ noncontrollers predict viral reservoir size

OBJECTIVE

Prior genomewide association studies have identified variation in major histocompatibility complex (MHC) class I alleles and C-C chemokine receptor type 5 gene (CCR5Δ32) as genetic predictors of viral control, especially in 'elite' controllers, individuals who remain virally suppressed in the absence of therapy.

DESIGN

Cross-sectional genomewide association study.

METHODS

We analyzed custom whole exome sequencing and direct human leukocyte antigen (HLA) typing from 202 antiretroviral therapy (ART)-suppressed HIV+ noncontrollers in relation to four measures of the peripheral CD4+ T-cell reservoir: HIV intact DNA, total (t)DNA, unspliced (us)RNA, and RNA/DNA. Linear mixed models were adjusted for potential covariates including age, sex, nadir CD4+ T-cell count, pre-ART HIV RNA, timing of ART initiation, and duration of ART suppression.

RESULTS

Previously reported 'protective' host genetic mutations related to viral setpoint (e.g. among elite controllers) were found to predict smaller HIV reservoir size. The HLA 'protective' B∗57:01 was associated with significantly lower HIV usRNA (q = 3.3 × 10-3), and among the largest subgroup, European ancestry individuals, the CCR5Δ32 deletion was associated with smaller HIV tDNA (P = 4.3 × 10-3) and usRNA (P = 8.7 × 10-3). In addition, genomewide analysis identified several single nucleotide polymorphisms in MX1 (an interferon stimulated gene) that were significantly associated with HIV tDNA (q = 0.02), and the direction of these associations paralleled MX1 gene eQTL expression.

CONCLUSIONS

We observed a significant association between previously reported 'protective' MHC class I alleles and CCR5Δ32 with the HIV reservoir size in noncontrollers. We also found a novel association between MX1 and HIV total DNA (in addition to other interferon signaling relevant genes, PPP1CB, DDX3X). These findings warrant further investigation in future validation studies.

Soluble low density lipoprotein receptor-related protein-1 levels in the differential diagnosis of myopericarditis versus acute coronary syndrome

INTRODUCTION

Differential diagnosis of myopericarditis (MPC) versus acute coronary syndromes (ACS) can be difficult in the emergency room (ER). Low density lipoprotein receptor-related protein-1 (LRP-1) is a transmembrane receptor with diverse biological functions. LRP-1 is increased after viral infections as a defense mechanism. sLRP-1 (soluble form) can be measured in the serum. We study the diagnostic sLRP-1 levels in patients with MPC, ACS and healthy controls.

METHODS

The study included consecutive patients who were admitted between the dates of 1.1.2018 and 1.1.2019 with the diagnosis of MPC or ACS. All patients reported to the ER with chest pain (CP) and elevated cardiac troponin levels. Control group (n = 61) was selected from healthy subjects. In addition to routine laboratory work up, serum sLRP-1 concentrations were measured on admission.

RESULTS

sLRP-1 levels were significantly higher in MPC, compared to controls (p = 0.005) and ACS (p = 0.001). Median (IQR) sLRP-1 levels in MPC, controls and ACS were 7.39 (22.42), 2.27 (1.74), 2.41 (0.98) μg/ml, respectively (p = 0.004). Among the covariates: sLRP-1, age, gender, HDL-C and LDL-C; only sLRP-1 differentiated a diagnosis of MPC versus ACS (OR = 1684, p = 0,046, CI for OR (1008-2812). The area under the curve (AUC) was measured as 0.79 [CI 0.62-0.95] in ROC analysis, p = 0.001; sLRP-1 had 69% sensitivity and 85% specificity for diagnosis of MPC with a cut-off value of 4.3 μg/ml.

CONCLUSION

sLRP-1 is a potential biomarker in the differential diagnosis of MPC versus ACS in ER. Future studies are needed to evaluate and develop the utility of sLRP-1 as a diagnostic and prognostic biomarker in MPC.

Residual Proviral Reservoirs: A High Risk for HIV Persistence and Driving Forces for Viral Rebound after Analytical Treatment Interruption

Antiretroviral therapy (ART) has dramatically suppressed human immunodeficiency virus (HIV) replication and become undetectable viremia. However, a small number of residual replication-competent HIV proviruses can still persist in a latent state even with lifelong ART, fueling viral rebound in HIV-infected patient subjects after treatment interruption. Therefore, the proviral reservoirs distributed in tissues in the body represent a major obstacle to a cure for HIV infection. Given unavailable HIV vaccine and a failure to eradicate HIV proviral reservoirs by current treatment, it is crucial to develop new therapeutic strategies to eliminate proviral reservoirs for ART-free HIV remission (functional cure), including a sterilizing cure (eradication of HIV reservoirs). This review highlights recent advances in the establishment and persistence of HIV proviral reservoirs, their detection, and potential eradication strategies.

Diversity of small molecule HIV-1 latency reversing agents identified in low- and high-throughput small molecule screens

The latency phenomenon produced by human immunodeficiency virus (HIV-1) prevents viral clearance by current therapies, and consequently development of a cure for HIV-1 disease represents a formidable challenge. Research over the past decade has resulted in identification of small molecules that are capable of exposing HIV-1 latent reservoirs, by reactivation of viral transcription, which is intended to render these infected cells sensitive to elimination by immune defense recognition or apoptosis. Molecules with this capability, known as latency-reversing agents (LRAs) could lead to realization of proposed HIV-1 cure strategies collectively termed "shock and kill," which are intended to eliminate the latently infected population by forced reactivation of virus replication in combination with additional interventions that enhance killing by the immune system or virus-mediated apoptosis. Here, we review efforts to discover novel LRAs via low- and high-throughput small molecule screens, and summarize characteristics and biochemical properties of chemical structures with this activity. We expect this analysis will provide insight toward further research into optimized designs for new classes of more potent LRAs.

Cat and Mouse: HIV Transcription in Latency, Immune Evasion and Cure/Remission Strategies

There is broad scientific and societal consensus that finding a cure for HIV infection must be pursued. The major barrier to achieving a cure for HIV/AIDS is the capacity of the HIV virus to avoid both immune surveillance and current antiretroviral therapy (ART) by rapidly establishing latently infected cell populations, termed latent reservoirs. Here, we provide an overview of the rapidly evolving field of HIV cure/remission research, highlighting recent progress and ongoing challenges in the understanding of HIV reservoirs, the role of HIV transcription in latency and immune evasion. We review the major approaches towards a cure that are currently being explored and further argue that small molecules that inhibit HIV transcription, and therefore uncouple HIV gene expression from signals sent by the host immune response, might be a particularly promising approach to attain a cure or remission. We emphasize that a better understanding of the game of "cat and mouse" between the host immune system and the HIV virus is a crucial knowledge gap to be filled in both cure and vaccine research.

Barriers for HIV Cure: The Latent Reservoir

Thirty-five years after the identification of HIV-1 as the causative agent of AIDS, we are still in search of vaccines and treatments to eradicate this devastating infectious disease. Progress has been made in understanding the molecular pathogenesis of this infection, which has been crucial for the development of the current therapy regimens. However, despite their efficacy at limiting active viral replication, these drugs are unable to purge the latent reservoir: a pool of cells that harbor transcriptionally inactive, but replication-competent HIV-1 proviruses, and that represent the main barrier to eradicate HIV-1 from affected individuals. In this review, we discuss advances in the field that have allowed a better understanding of HIV-1 latency, including the diverse cell types that constitute the latent reservoir, factors influencing latency, tools to study HIV-1 latency, as well as current and prospective therapeutic approaches to target these latently infected cells, so a functional cure for HIV/AIDS can become a reality.