Advances and challenges in antiretroviral therapy for acquired immunodeficiency syndrome

Metformin facilitates viral reservoir reactivation and their recognition by anti-HIV-1 envelope antibodies

The mechanistic target of rapamycin (mTOR) positively regulates multiple steps of the HIV-1 replication cycle. We previously reported that a 12-week supplementation of antiretroviral therapy (ART) with metformin, an indirect mTOR inhibitor used in type-2 diabetes treatment, reduced mTOR activation and HIV transcription in colon-infiltrating CD4+ T cells, together with systemic inflammation in nondiabetic people with HIV-1 (PWH). Herein, we investigated the antiviral mechanisms of metformin. In a viral outgrowth assay performed with CD4+ T cells from ART-treated PWH, and upon infection in vitro with replication-competent and VSV-G-pseudotyped HIV-1, metformin decreased virion release, but increased the frequency of productively infected CD4lowHIV-p24+ T cells. These observations coincided with increased BST2/tetherin (HIV release inhibitor) and Bcl-2 (pro-survival factor) expression, and improved recognition of productively infected T cells by HIV-1 envelope antibodies. Thus, metformin exerts pleiotropic effects on post-integration steps of the HIV-1 replication cycle and may be used to accelerate viral reservoir decay in ART-treated PWH.

Metformin Enhances Antibody-Mediated Recognition of HIV-Infected CD4+ T-Cells by Decreasing Viral Release

The mechanistic target of rapamycin (mTOR) positively regulates multiple steps of the HIV-1 replication cycle. We previously reported that a 12-weeks supplementation of antiretroviral therapy (ART) with metformin, an indirect mTOR inhibitor used in type-2 diabetes treatment, reduced mTOR activation and HIV transcription in colon-infiltrating CD4+ T-cells, together with systemic inflammation in nondiabetic people with HIV-1 (PWH). Herein, we investigated the antiviral mechanisms of metformin. In a viral outgrowth assay performed with CD4+ T-cells from ART-treated PWH, and upon infection in vitro with replication-competent and VSV-G-pseudotyped HIV-1, metformin decreased virion release, but increased the frequency of productively infected CD4lowHIV-p24+ T-cells. These observations coincided with increased BST2/Tetherin (HIV release inhibitor) and Bcl-2 (pro-survival factor) expression, and improved recognition of productively infected T-cells by HIV-1 Envelope antibodies. Thus, metformin exerts pleiotropic effects on post-transcription/translation steps of the HIV-1 replication cycle and may be used to accelerate viral reservoir decay in ART-treated PWH.

Knowledge about HIV and Stigmatizing Attitudes of Medical Students in Saudi Arabia Towards Patients with HIV/AIDS: A Cross-Sectional Nationwide Study

BACKGROUND

The Human Immunodeficiency Virus (HIV) and the social stigma directed toward patients with HIV are serious public health issues. We aimed to evaluate the HIV knowledge base and stigmatizing attitudes toward patients with HIV among students enrolled in medical schools in Saudi Arabia.

METHODS

This cross-sectional study included students at medical colleges in Saudi Arabia and was conducted between February and March 2023. We used non-random convenience sampling with an online chain referral via a validated Arabic questionnaire composed of 35 questions. Data were analyzed using descriptive and comparative statistics.

RESULTS

A total of 1,213 medical students (women: 56.6%) participated in the study. Students in clinical years had a higher level of HIV knowledge than their pre-clinical colleagues. Logistic regression analysis revealed that participants who gave incorrect answers to questions related to mother-to-child and casual contact HIV transmission had a higher likelihood of harboring a negative attitude towards patients with HIV. Conversely, those who correctly answered queries on prevention and treatment were less likely to have stigmatizing attitudes. A significant proportion of this cohort harbored negative attitudes toward patients with HIV, with the sex and geographic location of participants being significant predictors of negative attitudes.

CONCLUSION

Our data have revealed a significant percentage of medical students in Saudi Arabia to have misconceptions about HIV transmission and prevention, and stigmatizing attitudes toward patients with HIV, indicating a need for targeted interventions to enhance the HIV knowledge base in this population of future caregivers.

Role of microglia in HIV-1 infection

The usage of antiretroviral treatment (ART) has considerably decreased the morbidity and mortality related to HIV-1 (human immunodeficiency virus type 1) infection. However, ART is ineffective in eradicating the virus from the persistent cell reservoirs (e.g., microglia), noticeably hindering the cure for HIV-1. Microglia participate in the progression of neuroinflammation, brain aging, and HIV-1-associated neurocognitive disorder (HAND). Some methods have currently been studied as fundamental strategies targeting microglia. The purpose of this study was to comprehend microglia biology and its functions in HIV-1 infection, as well as to look into potential therapeutic approaches targeting microglia.

Functional Profile of CD8+ T-Cells in Response to HLA-A*02:01-Restricted Mutated Epitopes Derived from the Gag Protein of Circulating HIV-1 Strains from Medellín, Colombia

CD8⁺ T-cells play a crucial role in the control of HIV replication. HIV-specific CD8⁺ T-cell responses rapidly expand since the acute phase of the infection, and it has been observed that HIV controllers harbor CD8⁺ T-cells with potent anti-HIV capacity. The development of CD8⁺ T-cell-based vaccine against HIV-1 has focused on searching for immunodominant epitopes. However, the strong immune pressure of CD8⁺ T-cells causes the selection of viral variants with mutations in immunodominant epitopes. Since HIV-1 mutations are selected under the context of a specific HLA-I, the circulation of viral variants with these mutations is highly predictable based on the most prevalent HLA-I within a population. We previously demonstrated the adaptation of circulating strains of HIV-1 to the HLA-A*02 molecule by identifying mutations under positive selection located in GC9 and SL9 epitopes derived from the Gag protein. Also, we used an in silico prediction approach and evaluated whether the mutations found had a higher or lower affinity to the HLA-A*02. Although this strategy allowed predicting the interaction between mutated peptides and HLA-I, the functional response of CD8⁺ T-cells that these peptides induce is unknown. In the present work, peripheral blood mononuclear cells from 12 HIV-1⁺ HLA-A*02:01⁺ individuals were stimulated with the mutated and wild-type peptides derived from the GC9 and SL9 epitopes. The functional profile of CD8⁺ T-cells was evaluated using flow cytometry, and the frequency of subpopulations was determined according to their number of functions and the polyfunctionality index. The results suggest that the quality of the response (polyfunctionality) could be associated with the binding affinity of the peptide to the HLA molecule, and the functional profile of specific CD8⁺ T-cells to mutated epitopes in individuals under cART is maintained.

Factors associated with human immunodeficiency virus-1 low-level viremia and its impact on virological and immunological outcomes: A retrospective cohort study in Beijing, China

OBJECTIVES

We evaluated the impact of low-level viremia (LLV) on virological failure and immune reconstitution among people living with human immunodeficiency virus type 1 (HIV-1) treated with different antiretroviral regimens in Beijing, China.

METHODS

Human immunodeficiency virus type 1-positive adults who were registered at an infectious disease hospital in Beijing between January 1, 2005 and January 1, 2020 were administered antiretroviral therapy (ART) and whose viral load and CD4 counts were monitored were included in this retrospective cohort study. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with LLV in patients on different ART regimens. Cox proportional hazard model was employed to analyze the virological suppression and immune reconstitution cumulative probability in patients with LLV during follow-up.

RESULTS

A total of 10 124 HIV-1-infected participants was included. LLV occurred in 723 (8.2%), 204 (10.9%), 133 (8.6%), and 53 (14.4%) patients on first-line ART, second-line ART, third-line ART, and simplified regimens, respectively. Virological failure occurred in 514 (5.8%), 289 (15.5%), 86 (5.5%), and 34 (9.2%) patients on first-line ART, second-line ART, third-line ART, and simplified regimens, respectively. Earlier enrollment, lower baseline CD4 count, and higher baseline viral load were risk factors associated with LLV. LLV was related to increased hazards of virological failure compared to viral suppression of ≤50 copies/ml for those on first-line ART.

CONCLUSIONS

The risk of virological failure and poor immune reconstitution increases when LLV occurs. Targeted viral load and CD4 count monitoring are recommended for people living with HIV-1 with LLV to improve health-related outcomes.

Identification of Diagnostic Markers Correlated With HIV+ Immune Non-response Based on Bioinformatics Analysis

Background: HIV-infected immunological non-responders (INRs) are characterized by their inability to reconstitute CD4⁺ T cell pools after antiretroviral therapy. The risk of non-AIDS-related diseases in INRs is increased, and the outcome and prognosis of INRs are inferior to that of immunological responders (IRs). However, few markers can be used to define INRs precisely. In this study, we aim to identify further potential diagnostic markers associated with INRs through bioinformatic analyses of public datasets.

Methods: This study retrieved the microarray data sets of GSE106792 and GSE77939 from the Gene Expression Omnibus (GEO) database. After merging two microarray data and adjusting the batch effect, differentially expressed genes (DEGs) were identified. Gene Ontology (GO) resource and Kyoto Encyclopedia of Genes and Genomes (KEGG) resource were conducted to analyze the biological process and functional enrichment. We performed receiver operating characteristic (ROC) curves to filtrate potential diagnostic markers for INRs. Gene Set Enrichment Analysis (GSEA) was conducted to perform the pathway enrichment analysis of individual genes. Single sample GSEA (ssGSEA) was performed to assess scores of immune cells within INRs and IRs. The correlations between the diagnostic markers and differential immune cells were examined by conducting Spearman’s rank correlation analysis. Subsequently, miRNA-mRNA-TF interaction networks in accordance with the potential diagnostic markers were built with Cytoscape. We finally verified the mRNA expression of the diagnostic markers in clinical samples of INRs and IRs by performing RT-qPCR.

Results: We identified 52 DEGs in the samples of peripheral blood mononuclear cells (PBMC) between INRs and IRs. A few inflammatory and immune-related pathways, including chronic inflammatory response, T cell receptor signaling pathway, were enriched. FAM120AOS, LTA, FAM179B, JUN, PTMA, and SH3YL1 were considered as potential diagnostic markers. ssGSEA results showed that the IRs had significantly higher enrichment scores of seven immune cells compared with IRs. The miRNA-mRNA-TF network was constructed with 97 miRNAs, 6 diagnostic markers, and 26 TFs, which implied a possible regulatory relationship.

Conclusion: The six potential crucial genes, FAM120AOS, LTA, FAM179B, JUN, PTMA, and SH3YL1, may be associated with clinical diagnosis in INRs. Our study provided new insights into diagnostic and therapeutic targets.

Persistent Inflammation and Non-AIDS Comorbidities During ART: Coming of the Age of Monocytes

Monocytes are innate immune cells that serve as the first line of defense against pathogens by engulfing and destroying pathogens or by processing and presenting antigens to initiate adaptive immunity and stimulate immunological responses. Monocytes are classified into three types: classical, intermediate, and non-classical monocytes, each of which plays a particular function in response to pathogens. Human immunodeficiency virus type 1 (HIV-1) infection disrupts the balance of monocyte subsets, and the quantity and function of monocytes will not fully recover even with long-term antiretroviral therapy (ART). Monocytes are vital for the establishment and maintenance of HIV-1 latent viral reservoirs and are closely related to immune dysfunction even after ART. Therefore, the present review focuses on the phenotypic function of monocytes and their functions in HIV-1 infection to elucidate their roles in HIV patients.