Diminished Peripheral CD29hi Cytotoxic CD4+ T Cells Are Associated With Deleterious Effects During SIV Infection

Cytotoxic CD4+ T cells (CD4+ CTLs) limit HIV pathogenesis, as evidenced in elite controllers (a subset of individuals who suppress the virus without the need for therapy). CD4+ CTLs have also been shown to kill HIV-infected macrophages. However, little is known about their contribution towards HIV persistence, how they are affected following exposure to immune modulators like morphine, and what factors maintain their frequencies and function. Further, the lack of robust markers to identify CD4+ CTLs in various animal models limits understanding of their role in HIV pathogenesis. We utilized various PBMC samples obtained from SIV infected and cART treated rhesus macaques exposed to morphine or saline and subjected to flow cytometry evaluations. Thereafter, we compared and correlated the expression of CD4+ CTL-specific markers to viral load and viral reservoir estimations in total CD4+ T cells. We found that CD29 could be reliably used as a marker to identify CD4+ CTLs in rhesus macaques since CD29hi CD4+ T cells secrete higher cytotoxic and proinflammatory cytokines following PMA/ionomycin or gag stimulation. In addition, this immune cell subset was depleted during untreated SIV infection. Strikingly, we also observed that early initiation of cART reconstitutes depleted CD29hi CD4+ T cells and restores their function. Furthermore, we noted that morphine exposure reduced the secretion of proinflammatory cytokines/cytotoxic molecules in CD29hi CD4+ T cells. Lastly, increased functionality of CD29hi CD4+ T cells as depicted by elevated levels of either IL-21 or granzyme B hi T Bet+ gag specific responses were linked to limiting the size of the replication-competent reservoir during cART treatment. Collectively, our data suggest that CD4+ CTLs are crucial in limiting SIV pathogenesis and persistence.

Restored lncRNAs After ART Therapy Have Potential Key Roles in the Recovery From AIDS

Background: Many studies have shown that long noncoding RNAs (lncRNAs) derived from the host and human immunodeficiency virus (HIV) itself play important roles in virus-host interactions and viral pathogenesis. To identify potential key lncRNAs in the regulation of HIV pathogenesis, transcriptome analysis of peripheral blood mononuclear cells (PBMCs), which were derived from 6 HIV/acquired immunodeficiency syndrome (AIDS) subjects pre-HAART and post-HAART with effective control of plasma viremia (<20 HIV RNA copies/ml) and 6 healthy subjects, was performed by RNA sequencing (RNA-seq).Results: We identified a total of 974 lncRNAs whose expression levels were restored to normal after ART therapy. The results of the cis-acting analysis showed that only six lncRNAs have cis-regulated target genes, among which the target gene RP11-290F5.1, interferon regulatory factors 2 (IRF2), could promote HIV replication. We also identified lncRNA CTB-119C2.1, which regulates most mRNAs with differential expression between pre- and post-HAART, and the differences were significant. We selected lncRNA CTB-119C2.1 for qRT–PCR verification, and the results were consistent with those of RNA-seq. RAB3A and GADD45A, two of the lncRNA CTB-119C2.1-associated genes, have been shown to be associated with HIV infection. KEGG analysis of lncRNA CTB-119C2.1-associated genes revealed that most of the genes are involved in the p53 signaling pathway or pathways related to cell circulation and DNA replicationConclusion: In this study, we used RNA-seq to systematically compare the expression profiles of lncRNAs in HIV subjects between untreated and treated time points. We successfully identified some lncRNAs with differential expression during certain periods (no HIV infection, HIV infection before treatment, and after treatment). Their expression is associated with viral loads, and some of their regulating genes were found to be involved in HIV pathogenesis through bioinformatic analysis. These findings could help to reveal the underlying molecular mechanism of the progression of AIDS.

Perspectives on Non-BLT Humanized Mouse Models for Studying HIV Pathogenesis and Therapy

A variety of humanized mice, which are reconstituted only with human hematopoietic stem cells (HSC) or with fetal thymus and HSCs, have been developed and widely utilized as in vivo animal models of HIV-1 infection. The models represent some aspects of HIV-mediated pathogenesis in humans and are useful for the evaluation of therapeutic regimens. However, there are several limitations in these models, including their incomplete immune responses and poor distribution of human cells to the secondary lymphoid tissues. These limitations are common in many humanized mouse models and are critical issues that need to be addressed. As distinct defects exist in each model, we need to be cautious about the experimental design and interpretation of the outcomes obtained using humanized mice. Considering this point, we mainly characterize the current conventional humanized mouse reconstituted only with HSCs and describe past achievements in this area, as well as the potential contributions of the humanized mouse models for the study of HIV pathogenesis and therapy. We also discuss the use of various technologies to solve the current problems. Humanized mice will contribute not only to the pre-clinical evaluation of anti-HIV regimens, but also to a deeper understanding of basic aspects of HIV biology.