HIV-1 gp120 influences the expression of microRNAs in human monocyte-derived dendritic cells via STAT3 activation

MicroRNAs and exosomes: key players in HIV pathogenesis

OBJECTIVES

HIV infection is well known to cause impairment of the human immune system, and until recently was a leading cause of death. It has been shown that T lymphocytes are the main targets of HIV. The virus inactivates T lymphocytes by interfering with a wide range of cellular and molecular targets, leading to suppression of the immune system. The objective of this review is to investigate to what extent microRNAs (miRNAs) are involved in HIV pathogenesis.

METHODS

The scientific literature (Pubmed and Google scholar) for the period 1988-2019 was searched.

RESULTS

Mounting evidence has revealed that miRNAs are involved in viral replication and immune response, whether by direct targeting of viral transcripts or through indirect modulation of virus-related host pathways. In addition, exosomes have been found to act as nanoscale carriers involved in HIV pathogenesis. These nanovehicles target their cargos (i.e. DNA, RNA, viral proteins and miRNAs) leading to alteration of the behaviour of recipient cells.

CONCLUSIONS

miRNAs and exosomes are important players in HIV pathogenesis. Additionally, there are potential diagnostic applications of miRNAs as biomarkers in HIV infection.

MicroRNA expression profiling of peripheral blood mononuclear cells associated with syphilis

BACKGROUND

Treponema pallidum (T. pallidum) infection evokes significant immune responses, resulting in tissue damage. The immune mechanism underlying T. pallidum infection is still unclear, although microRNAs (miRNAs) have been shown to influence immune cell function and, consequently, the generation of antibody responses during other microbe infections. However, these mechanisms are unknown for T. pallidum.

METHODS

In this study, we performed a comprehensive analysis of differentially expressed miRNAs in healthy individuals, untreated patients with syphilis, patients in the serofast state, and serologically cured patients. miRNAs were profiled from the peripheral blood of patients obtained at the time of serological diagnosis. Then, both the target sequence analysis of these different miRNAs and pathway analysis were performed to identify important immune and cell signaling pathways. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed for microRNA analysis.

RESULTS

A total of 74 differentially regulated miRNAs were identified. Following RT-qPCR confirmation, three miRNAs (hsa-miR-195-5p, hsa-miR-223-3p, hsa-miR-589-3p) showed significant differences in the serofast and serologically cured states (P < 0.05). One miRNA (hsa-miR-195-5p) showed significant differences between untreated patients and healthy individuals.

CONCLUSIONS

This is the first study of miRNA expression differences in peripheral blood mononuclear cells (PBMCs) in different stages of T. pallium infection. Our study suggests that the combination of three miRNAs has great potential to serve as a non-invasive biomarker of T. pallium infections, which will facilitate better diagnosis and treatment of T. pallium infections.

MiR-125b Suppression Inhibits Apoptosis and Negatively Regulates Sema4D in Avian Leukosis Virus-Transformed Cells

Subgroup J avian leukosis virus (ALV-J), an oncogenic retrovirus, causes hemangiomas and myeloid tumors in chickens. We previously showed that miR-125b is down-regulated in ALV-J-induced tumors. This study aimed to investigate the possible role of miR-125b in ALV-J-mediated infection and tumorigenesis. Knockdown of miR-125b expression in HP45 cells reduced, whereas over-expression induced late-stage apoptosis. Bioinformatics analysis and luciferase activity assays indicate that miR-125b targets Semaphorin 4D/CD100 (Sema4D) by binding the 3'-untranslated region of messenger RNA (mRNA). Up-regulation of miR-125b in the DF1 cell line suppressed Sema4D expression, whereas miR-125 down-regulation increased Sema4D expression levels. To uncover the function of Sema4D during ALV-J infection, animal infection experiments and in vitro assays were performed and show that Sema4D mRNA levels were up-regulated in ALV-J-infected tissues and cells. Finally, functional experiments show that miR-125 down-regulation and Sema4D over-expression inhibited apoptosis in HP45 cells. These results suggest that miR-125b and its target Sema4D might play an important role in the aggressive growth of HP45 cells induced by avian leukosis viruses (ALVs). These findings improve our understanding of the underlying mechanism of ALV-J infection and tumorigenesis.

IL-23 and dendritic cells: What are the roles of their mutual attachment in immune response and immunotherapy?

Interleukin-23 (IL-23) is a cytokine that is composed of the subunits p19 and p40, while its receptor (IL-23R) consists of two subunits, that is, IL-23Rα and IL-12Rβ1. The interaction between IL-23 and IL-23R is necessary for exerting cardinal biological effects upon certain cell types, including promotion of memory T cell proliferation and Th17 cell-mediated IL-17 secretion. Accordingly, dendritic cells (DCs) are one of the main sources for IL-23 secretion. Interestingly, IL-23R is also present on the DC plasma membrane, suggesting that IL-23 potentially acts on DCs via an autocrine manner. In this review, we have summarized a variety of IL-23-mediated effects on the intracellular signaling pathways such as Janus kinase 2, tyrosine kinase 2, signal transducer and activator of transcription (STAT), mitogen-activated protein kinase signaling, and so forth, which may underlie numerous processes such as DC maturation, antigen presentation, T cell proliferation/activation, and cytokine secretion, which may be implicated in many immune-related diseases through IL-23/DC interactions. Accordingly, these signaling pathways are extensively involved in the pathogenesis and progression of numerous diseases, including autoimmune disease (e.g., atopic dermatitis, asthma, and multiple sclerosis) and infection (e.g., bacterial, fungal, and viral infections). Taken together, they are potentially applicable to novel but promising strategies for treating numerous diseases associated with the mutual attachment of IL-23 and DCs.

Dual requirement for STAT signaling in dendritic cell immunobiology

Dendritic cells (DC) represent an attractive target for therapeutic manipulation of the immune system and enhancement of insufficient immune response in cancer. STAT family members play key roles in the differentiation and activation of DC, a feature that is currently being exploited in DC-based therapies. We previously reported that the small-molecule Stattic, originally developed as a STAT3-specific inhibitor, also inhibits STAT1 and STAT2 phosphorylation in DC exposed to cytokines or LPS. Aim of this study was to investigate the functional consequences of in vitro treatment with Stattic on DC immunobiology. Interestingly, we observed an opposite effect of Stattic on DC immunophenotype depending on the activation state. While the expression of costimulatory, coinhibitory, MHC class II and CD83 molecules was enhanced in immature DC exposed to Stattic, the LPS induced up-modulation of these molecules was strongly repressed. An effective blockade of LPS-induced secretion of proinflammatory cytokines and capacity to stimulate a Th1 polarization was also observed in the presence of Stattic. Our results indicate that the immunological consequences of STAT inhibition in DC vary depending on the cell activation state. This knowledge is of relevance for anticipating potential effects of STAT-targeted therapeutics, and pursuing selective DC manipulation in clinical applications.

Identification of Host Micro RNAs That Differentiate HIV-1 and HIV-2 Infection Using Genome Expression Profiling Techniques

While human immunodeficiency virus type 1 and 2 (HIV-1 and HIV-2) share many similar traits, major differences in pathogenesis and clinical outcomes exist between the two viruses. The differential expression of host factors like microRNAs (miRNAs) in response to HIV-1 and HIV-2 infections are thought to influence the clinical outcomes presented by the two viruses. MicroRNAs are small non-coding RNA molecules which function in transcriptional and post-transcriptional regulation of gene expression. MiRNAs play a critical role in many key biological processes and could serve as putative biomarker(s) for infection. Identification of miRNAs that modulate viral life cycle, disease progression, and cellular responses to infection with HIV-1 and HIV-2 could reveal important insights into viral pathogenesis and provide new tools that could serve as prognostic markers and targets for therapeutic intervention. The aim of this study was to elucidate the differential expression profiles of host miRNAs in cells infected with HIV-1 and HIV-2 in order to identify potential differences in virus-host interactions between HIV-1 and HIV-2. Differential expression of host miRNA expression profiles was analyzed using the miRNA profiling polymerase chain reaction (PCR) arrays. Differentially expressed miRNAs were identified and their putative functional targets identified. The results indicate that hsa-miR 541-3p, hsa-miR 518f-3p, and hsa-miR 195-3p were consistently up-regulated only in HIV-1 infected cells. The expression of hsa-miR 1225-5p, hsa-miR 18a* and hsa-miR 335 were down modulated in HIV-1 and HIV-2 infected cells. Putative functional targets of these miRNAs include genes involved in signal transduction, metabolism, development and cell death.