Antiretrovirals to CCR5 CRISPR/Cas9 gene editing - A paradigm shift chasing an HIV cure

Model-based evaluation of the impact of a potential HIV cure on HIV transmission dynamics

The development of an HIV cure is a global health priority, with the target product profile (TPP) for an HIV cure guiding research efforts. Using a mathematical model calibrated to data from men who have sex with men (MSM) in the Netherlands, we assessed whether an effective cure could help end the HIV epidemic. Following the TPP, we evaluated two scenarios: (i) HIV remission, where the virus is suppressed in an individual without ongoing antiretroviral therapy (ART) but may rebound, and (ii) HIV eradication, which aims to completely remove the virus from the individual. Here, we show that sustained HIV remission (without rebound) or HIV eradication could reduce new HIV infections compared to a scenario without a cure. In contrast, transient HIV remission with a risk of rebound could increase new infections if rebounds are not closely monitored, potentially undermining HIV control efforts. Our findings emphasize the critical role of cure characteristics in maximizing cure benefits for public health and highlight the need to align HIV cure research with public health objectives to end the HIV epidemic.

Deep Thought on the HIV Cured Cases: Where Have We Been and What Lies Ahead?

Antiretroviral therapy (ART) can effectively suppress the replication of human immunodeficiency virus (HIV), but it cannot completely eradicate the virus. The persistent existence of the HIV reservoir is a major obstacle in the quest for a cure. To date, there have been a total of seven cured cases of HIV worldwide. These patients all cleared HIV while undergoing allogeneic stem cell transplantation (allo-HSCT) for hematological malignancies. However, in these cases, the specific mechanism by which allo-HSCT leads to the eradication of HIV remains unclear, so it is necessary to conduct an in-depth analysis. Due to the difficulty in obtaining donors and the risks associated with transplantation, this treatment method is not applicable to all HIV patients. There is still a need to explore new treatment strategies. In recent years, emerging therapies such as neutralizing antibody immunotherapy, chimeric antigen receptor T cell (CAR-T) therapy, gene editing, and antiviral therapies targeting the reservoir have attracted wide attention due to their ability to effectively inhibit HIV replication. This article first elaborates on the nature of the HIV reservoir, then deeply explores the treatment modalities and potential success factors of HIV cured cases, and finally discusses the current novel treatment methods, hoping to provide comprehensive and feasible strategies for achieving the cure of HIV.

Targeting CCR5: A central approach to HIV treatment and cure strategies

CCR5, a co-receptor critical for R5-tropic HIV entry into host cells, remains a key target for therapeutic interventions. HIV utilizes CCR5, expressed on T cells and macrophages, to facilitate viral entry. Genetic variants, such as the CCR5Δ32 homozygous mutation that confers protection to HIV infection, have made CCR5 a main target for gene-editing technologies, small-molecule inhibitors, and monoclonal antibody-based therapies. Recent studies emphasize the importance of regulating CCR5 expression at transcriptional and post-transcriptional levels and integrating this approach with traditional therapies. Particularly, the role of heterozygous CCR5Δ32 carriers who are HIV seropositive highlights the potential for targeting CCR5 in combination with other immune-regulatory mechanisms. This may lead to more effective treatment strategies and, ultimately, a functional cure for HIV. This minireview discusses the role of CCR5 in HIV pathogenesis and explores the potential of genetic and therapeutic interventions targeting CCR5 as an innovative strategy in the continued battle against HIV.

Exploring potential associations between the human microbiota and reservoir of latent HIV

BACKGROUND

The rapid establishment and persistence of latent HIV-1 reservoirs is one of the main obstacles towards an HIV cure. While antiretroviral therapy supresses viral replication, it does not eradicate the latent reservoir of HIV-1-infected cells. Recent evidence suggests that the human microbiome, particularly the gut microbiome, may have the potential to modulate the HIV-1 reservoir. However, literature is limited and the exact mechanisms underlying the role of the microbiome in HIV immunity and potential regulation of the viral reservoir remain poorly understood.

RESULTS

Here, we review updated knowledge on the associations between the human microbiome and HIV reservoir across different anatomical sites, including the gut, the lungs and blood. We provide an overview of the predominant taxa associated with prominent microbiome changes in the context of HIV infection. Based on the current evidence, we summarize the main study findings, with specific focus on consistent bacterial and related byproduct associations. Specifically, we address the contribution of immune activation and inflammatory signatures on HIV-1 persistence. Furthermore, we discuss possible scenarios by which bacterial-associated inflammatory mediators, related metabolites and host immune signatures may modulate the HIV reservoir size. Finally, we speculate on potential implications of microbiome-based therapeutics for future HIV-1 cure strategies, highlighting challenges and limitations inherent in this research field.

CONCLUSIONS

Despite recent advances, this review underscores the need for further research to deepen the understanding of the complex interplay between the human microbiome and HIV reservoir. Further integrative multi-omics assessments and functional studies are crucial to test the outlined hypothesis and to identify potential therapeutic targets ultimately able to achieve an effective cure for HIV.

Interventions during Early Infection: Opening a Window for an HIV Cure?

Although combination antiretroviral therapy (ART) has been a landmark achievement for the treatment of human immunodeficiency virus (HIV), an HIV cure has remained elusive. Elimination of latent HIV reservoirs that persist throughout HIV infection is the most challenging barrier to an HIV cure. The progressive HIV infection is marked by the increasing size and diversity of latent HIV reservoirs until an effective immune response is mobilized, which can control but not eliminate HIV infection. The stalemate between HIV replication and the immune response is manifested by the establishment of a viral set point. ART initiation during the early stage limits HIV reservoir development, preserves immune function, improves the quality of life, and may lead to ART-free viral remission in a few people living with HIV (PLWH). However, for the overwhelming majority of PLWH, early ART initiation alone does not cure HIV, and lifelong ART is needed to sustain viral suppression. A critical area of research is focused on determining whether HIV could be functionally cured if additional treatments are provided alongside early ART. Several HIV interventions including Block and Lock, Shock and Kill, broadly neutralizing antibody (bNAb) therapy, adoptive CD8+ T cell therapy, and gene therapy have demonstrated delayed viral rebound and/or viral remission in animal models and/or some PLWH. Whether or not their application during early infection can improve the success of HIV remission is less studied. Herein, we review the current state of clinical and investigative HIV interventions and discuss their potential to improve the likelihood of post-treatment remission if initiated during early infection.