MiRNA-mediated mechanisms of immune dysfunction in HIV patients

人类免疫缺陷病毒1 （HIV-1）主要感染CD4+ T细胞。它也感染骨髓细胞，在HIV+患者中观察到的慢性炎症有很大的贡献。持续的免疫激活可能导致免疫细胞功能障碍，并增加发生hiv相关恶性肿瘤的风险，包括卡波西氏肉瘤（KS）。免疫失调和炎症环境是KS疱疹病毒（KSHV）再激活和KS发展的危险因素。MicroRNAs （miRNAs）是一种短的非编码rna，通过抑制或降解靶mrna来调节基因表达。mirna与巨噬细胞成熟及其向炎症部位的募集有关。除了作为细胞内基因调节剂的作用外，mirna还可以通过外泌体分泌，并在远处影响受体细胞的基因表达。我们从HIV受试者和健康对照中分离出CD14+细胞，并向M1和M2表型极化。对三个预先选择的mirna的表达分析显示，正如预期的那样，在对照细胞极化过程中，miR-155-Sp和miR-146a-5p的表达强烈上调；然而，hiv衍生的细胞无法上调这两种mirna。相反，与对照组相比，来自HIV患者的巨噬细胞中miR-223-3p的下调程度更高。由于miR-146a和miR-155在内毒素耐受性（一种防止过度免疫激活的过渡状态）中发挥关键作用，hiv衍生的巨噬细胞在激活时未能上调这些mirna可能表明这些细胞控制炎症反应的能力降低。事实上，极化巨噬细胞的基因表达分析显示，与对照组相比，HIV受试者的m1和M2巨噬细胞的免疫反应功能失调。此外，我们在患有或不患有KS的HIV受试者的血浆外泌体中发现了失调的mirna。我们假设HIV +受试者循环单核细胞和外泌体中miRNA表达失调导致巨噬细胞功能失调，促进炎症环境和肿瘤发展。

The Human Immunodeficiency Virus 1 (HIV-1) mainly infect CD4+ T cells. It also infects myeloid cells, highly contributing to the chronic inflammation observed in HIV+ patients. Persistence of immune activation could lead to immune cell dysfunction and increased risk of developing HIV-associated malignancies, including Kaposi's Sarcoma (KS). Immune dysregulation and an inflammatory environment are risk factors for KS herpes virus (KSHV) reactivation and KS development. MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression by inhibition or degradation of target mRNAs. MiRNAs are implicated in the macrophage maturation as well as their recruitment to inflammatory sites. In addition to their role as intracellular gene regulators, miRNAs can be secreted through exosomes and affect gene expression on recipient cells at distant sites. We isolated CD14+ cells from HIV subjects and healthy controls and polarized toward M1 and M2 phenotypes. Expression analysis of three pre-selected miRNAs revealed, as expected, a strong up-regulation of miR-155-Sp and miR-146a-5p during polarization of the controls cells; however, HIV-derived cells failed to upregulate these two miRNAs. Conversely, miR-223-3p, was more downregulated in macrophages derived from HIV patients compared to controls. As miR-146a and miR-155 play key roles in endotoxin tolerance (a transition state that prevents an excessive immune activation), failure to up-regulate those miRNAs by HIV-derived macrophages upon their activation may indicate a reduced ability of these cells to control inflammatory responses. Indeed, gene expression analysis of polarized macrophages revealed a dysfunctional immune response for both M 1 and M2 macrophages from HIV subjects compared to controls. In addition, we found dysregulated miRNAs in plasma exosomes from HIV subjects with or without KS. We hypothesize that dysregulated miRNA expression in circulating monocytes and exosomes in HIV +-subjects leads to dysfunctional macrophages, contributing to an inflammatory environment and tumor development.