S100A14 Is Increased in Activated NK Cells and Plasma of HIV-Exposed Seronegative People Who Inject Drugs and Promotes Monocyte-NK Crosstalk.

BACKGROUND: HIV-exposed seronegative people who inject drugs (HESN-PWID) have been shown to have increased natural killer (NK) cell and myeloid activation when compared with control donors. METHODS: We investigated potential mechanisms maintaining NK activation by conducting quantitative proteome comparisons of NK cells from HESN-PWID subjects and control donors. Proteins upregulated in NK cells were measured in the plasma of HESN-PWID subjects by ELISA and further investigated for their ability to induce innate immune activation in vitro. RESULTS: The NK cell proteome comparison showed markedly higher levels of interferon-stimulated proteins and S100 proteins, including S100A14. Consistent with these results, we observed significantly higher levels of S100A14 in the plasma of HESN-PWID subjects compared with controls (P = 0.033, n = 25). In vitro, the addition of recombinant S100A14 protein significantly activated NK cells in a peripheral blood mononuclear cell mixture (P = 0.011, n = 9), but not purified NK cells alone. Treatment of purified monocytes with recombinant S100A14 protein induced secretion of TNF-alpha and led to significantly higher NK CD69 activation (P = 0.0156, n = 7) in a co-culture through a TLR4-dependent interaction. CONCLUSIONS: Our study identified S100A14 as a novel protein increased within NK cells and plasma of HESN-PWID subjects with the capacity to sustain NK activation through TLR4-dependent activation of myeloid cells.

Dimethyl Fumarate Prevents HIV-Induced Lysosomal Dysfunction and Cathepsin B Release from Macrophages.

HIV-associated neurocognitive disorders (HAND) are prevalent despite combined antiretroviral therapy, affecting nearly half of HIV-infected patients worldwide. During HIV infection of macrophages secretion of the lysosomal protein, cathepsin B, is increased. Secreted cathepsin B has been shown to induce neurotoxicity. Oxidative stress is increased in HIV-infected patients, while antioxidants are decreased in monocytes from patients with HIV-associated dementia (HAD). Dimethyl fumarate (DMF), an antioxidant, has been reported to decrease HIV replication and neurotoxicity mediated by HIV-infected macrophages. Thus, we hypothesized that DMF will decrease cathepsin B release from HIV-infected macrophages by preventing oxidative stress and enhancing lysosomal function. Monocyte-derived macrophages (MDM) were isolated from healthy donors, inoculated with HIV-1ADA, and treated with DMF following virus removal. After 12 days post-infection, HIV-1 p24 and total cathepsin B levels were measured from HIV-infected MDM supernatants using ELISA; intracellular reactive oxygen and nitrogen species (ROS/RNS) were measured from MDM lysates, and functional lysosomes were assessed using a pH-dependent lysosomal dye. Neurons were incubated with serum-free conditioned media from DMF-treated MDM and neurotoxicity was determined using TUNEL assay. Results indicate that DMF reduced HIV-1 replication and cathepsin B secretion from HIV-infected macrophages in a dose-dependent manner. Also, DMF decreased intracellular ROS/RNS levels, and prevented HIV-induced lysosomal dysfunction and neuronal apoptosis. In conclusion, the improvement in lysosomal function with DMF treatment may represent the possible mechanism to reduce HIV-1 replication and cathepsin B secretion. DMF represents a potential therapeutic strategy against HAND.

HIV gp120 sequence variability associated with HAND in Hispanic Women.

OBJECTIVE: HIV-1 variants with different tropisms are associated with various neuropathologies. This study intends to determine if this correlation is determined by unique viral env sequences. We hypothesize that HIV-1 envelope gene sequence changes are associated with cognition status. METHODS: Viral RNA was extracted from peripheral blood mononuclear cells (PBMCs) co-cultures derived from HIV-1 infected Hispanic women that had been characterized for HIV associated neurocognitive disorders (HAND). RESULTS: Analyses of the C2V4 region of HIV gp120 demonstrated that increased sequence diversity correlates with cognition status as sequences derived from subjects with normal cognition exhibited less diversity than sequences derived from subjects with cognitive impairment. In addition, differences in V3 and V4 loop charges were also noted as well as differences in the N-glycosylation of the V4 region. CONCLUSIONS: Our data suggest that the genetic signature within the C2V4 region may contribute to the pathogenesis of HAND. HIV env sequence characteristics for the isolates grouped in milder forms of HAND can provide insightful information of prognostic value to assess neurocognitive status in HIV+ subjects, particularly during the era of highly prevalent milder forms of HAND.

Proteomic analysis of HIV-infected macrophages.

Mononuclear phagocytes (monocytes, macrophages, and microglia) play an important role in innate immunity against pathogens including HIV. These cells are also important viral reservoirs in the central nervous system and secrete inflammatory mediators and toxins that affect the tissue environment and function of surrounding cells. In the era of antiretroviral therapy, there are fewer of these inflammatory mediators. Proteomic approaches including surface enhancement laser desorption ionization, one- and two-dimensional difference in gel electrophoresis, and liquid chromatography tandem mass spectrometry have been used to uncover the proteins produced by in vitro HIV-infected monocytes, macrophages, and microglia. These approaches have advanced the understanding of novel mechanisms for HIV replication and neuronal damage. They have also been used in tissue macrophages that restrict HIV replication to understand the mechanisms of restriction for future therapies. In this review, we summarize the proteomic studies on HIV-infected mononuclear phagocytes and discuss other recent proteomic approaches that are starting to be applied to this field. As proteomic instruments and methods evolve to become more sensitive and quantitative, future studies are likely to identify more proteins that can be targeted for diagnosis or therapy and to uncover novel disease mechanisms.