Multiple genome-wide studies have identified associations between outcome of HIV infection and polymorphisms in/around the gene encoding the HIV co-receptor CCR5, but the functional basis for the strongest of these associations, rs1015164 A/G, is unknown. We found that rs1015164, located 34KB downstream of CCR5, marks variation in an ATF1 binding site that controls expression of the antisense long non-coding RNA CCR5AS. Knockdown or enhancement of CCR5AS expression resulted in a corresponding change in CCR5 expression on CD4+ T cells. CCR5AS interfered with interactions between the RNA-binding protein Raly and the CCR5 3’ untranslated region, protecting CCR5 mRNA from Raly-mediated degradation. Reduction in CCR5 expression through inhibition of CCR5AS diminished infection of CD4+ T cells with CCR5-tropic HIV in vitro. These data represent a rare determination of the functional importance of a genome-wide disease association where expression of a long non-coding RNA affects level of HIV infection and disease progression.
BackgroundDevelopment of AIDS vaccines for effective prevention of circulating HIV-1 is required, but no trial has demonstrated definitive effects on the prevention. Several recent T-cell vaccine trials showed no protection against HIV-1 acquisition although the vaccines induced HIV-1-specific T-cell responses, suggesting that the vaccine-induced T cells have insufficient capacities to suppress HIV-1 replication and/or cross-recognize circulating HIV-1. Therefore, it is necessary to develop T-cell vaccines that elicit T cells recognizing shared protective epitopes with strong ability to suppress HIV-1. We recently designed T-cell mosaic vaccine immunogens tHIVconsvX composed of 6 conserved Gag and Pol regions and demonstrated that the T-cell responses to peptides derived from the vaccine immunogens were significantly associated with lower plasma viral load (pVL) and higher CD4+ T-cell count (CD4 count) in HIV-1-infected, treatment-naive Japanese individuals. However, it remains unknown T cells of which specificities have the ability to suppress HIV-1 replication. In the present study, we sought to identify more T cells specific for protective Gag epitopes in the vaccine immunogens, and analyze their abilities to suppress HIV-1 replication and recognize epitope variants in circulating HIV-1.ResultsWe determined 17 optimal Gag epitopes and their HLA restriction, and found that T-cell responses to 9 were associated significantly with lower pVL and/or higher CD4 count. T-cells recognizing 5 of these Gag peptides remained associated with good clinical outcome in 221 HIV-1-infected individuals even when comparing responders and non-responders with the same restricting HLA alleles. Although it was known previously that T cells specific for 3 of these protective epitopes had strong abilities to suppress HIV-1 replication in vivo, here we demonstrated equivalent abilities for the 2 novel epitopes. Furthermore, T cells against all 5 Gag epitopes cross-recognized variants in majority of circulating HIV-1.ConclusionsWe demonstrated that T cells specific for 5 Gag conserved epitopes in the tHIVconsvX have ability to suppress replication of circulating HIV-1 in HIV-1-infected individuals. Therefore, the tHIVconsvX vaccines have the right specificity to contribute to prevention of HIV-1 infection and eradication of latently infected cells following HIV-1 reactivation.Electronic supplementary materialThe online version of this article (10.1186/s12977-018-0429-y) contains supplementary material, which is available to authorized users.
RAB GTPase 5A (RAB5A), a member of the Rab subfamily of small GTPases, acts as an oncogene and has been associated with various key cellular functions, including cell growth, differentiation, apoptosis and angiogenesis. Recently, it has been reported that the Rab5a gene is involved in the progression of cancer. Hepatocellular carcinoma (HCC) is one of the most common and aggressive cancers, and it is usually associated with persistent hepatitis B virus (HBV) infections. Emerging evidence suggests that HBV alters microRNA (miRNA) expression profiles, but the mechanisms underlying this process have not yet been fully elucidated. Here, we examine how HBV affects the production of miR-101-1, which has been shown to be downregulated in HCC. We found that HBV could repress miR-101-3p by inhibiting its promoter activity. Downregulation of miR-101-3p promoted cancer cell growth and migration, and a specific miR-101-3p inhibitor was able to enhance proliferation and migration. Moreover, we identified Rab5a was one of the target genes of miR-101-3p in HBV-related HCC. Forced expression of miR-101-3p in liver cell lines resulted in a marked reduction of the expression of Rab5a at both the mRNA and protein level by directly targeting the 3'untranslated region of Rab5a. Overexpression of Rab5a resulted in a reversal of the suppression of proliferation and migration of SMMC-7721 cells mediated by miR-101-3p. Taken together, our data show that HBV can downregulate miR-101-3p expression by inhibiting its promoter activity and that downregulation of miR-101-3p promotes HCC cell proliferation and migration by targeting Rab5a. This provides new insights into the mechanisms of HBV-related HCC pathogenesis.
BackgroundAccumulating evidence showed that microRNAs are involved in development and progression of multiple tumors. Recent studies have found that miR-181a were dysregulated in several types of cancers, however, the function of miR-181a in hepatocellular carcinoma (HCC) remains unclear. In this study we assessed the potential association between miR-181a, HBV and HCC.MethodsThe expression of miR-181a in HBV-expressing cells was determined by using qRT-PCR. Dual-Luciferase reporter Assay, qRT-PCR and western blot were performed to investigate the target genes of miR-181a. The effects of miR-181a on HCC proliferation were analyzed by MTS and colony formation assay. Tumor growth assay was used to analyze the effect of miR-181a on tumor formation.ResultsHBV up-regulated miR-181a expression by enhancing its promoter activity. Overexpression of miR-181a in hepatoma cells promoted cell growth in vitro and tumor formation in vivo. Conversely, inhibition of miR-181a suppressed the proliferation of HBV-expressing cells. Mechanism investigation revealed that miR-181a inhibited the expression of transcription factor E2F5 by specifically targeting its mRNA 3′UTR. Moreover, E2F5 inhibition induced cell growth and rescued the suppressive effect of miR-181a inhibitor on the proliferation of SMMC-7721 cells. Interestingly, we also discovered that HBV could down-regulate E2F5 expression.ConclusionsThose results strongly suggested that HBV down-regulated E2F5 expression, in part, by up-regulating the expression of miR-181a. Up-regulation of miR-181a by HBV in hepatoma cells may contribute to the progression of HCC possibly by targeting E2F5, suggesting miR-181a plays important role in HCC development.
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