Modulation of indoleamine-2,3-dioxygenase expression and activity by HIV-1 in human macrophages

Human immunodeficiency virus (HIV) infection is often complicated by the development of acquired immunodeficiency syndrome (AIDS) dementia complex (ADC). Implications of kynurenine pathway (KP) are suggested in ADC and other inflammatories brain diseases. The first and regulatory enzyme of the KP is the indoleamine-2,3-dioxygenase (IDO). IDO activation is known to contribute to the modulation of the immune response during various infectious diseases particularly in AIDS. HIV and viral proteins can activate IDO in immune cells leading to an increase catabolism of tryptophan through the KP; the consequence being the production of immuno-modulative and neuroactive metabolites. This mechanism is likely to favour HIV persistence. The present study analysed concomitantly several parameters involved in IDO regulation and activity associated with HIV-1-infection. We investigated relevant intracellular and extracellular mechanisms involved in the regulation of IDO expression and activity during the HIV infection and replication in human monocyte-derived macrophages (MdM). Using a complementary set of in vitro experiments, we found that HIV-1/Ba-L infection induces IDO expression and increases its activity in MdM. We also showed that IDO activation by HIV-1 is likely to be a direct effect of the infection and seems to be independent of IFN-γ production.9 page(s

Plasmacytoid Dendritic Cell Dynamics Tune Interferon-Alfa Production in SIV-Infected Cynomolgus Macaques

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Macaque bone marrow pDC express lower CD123 and HLA-DR, display higher percentages of CD34+ and Ki67+ precursors than blood pDC, and are poor IFN-I producers.

<p>(<b>A</b>) CD34⁺ and Ki67⁺ pDC-precursor frequencies are higher in the bone marrow (BM) than in the blood (non-infected macaques, n = 6), and both CD123 and HLA-DR expressions are lower in BM pDC than blood pDC. From <b>left to right</b>: Percentage of CD34⁺ pDC precursors, percentage of Ki67⁺ pDC precursors, and CD123 and HLA-DR geometric MFI (gMFI) in BM and blood pDC. Dotplot showing Ki67 and CD34 expression by pDC in BM and blood, from one representative animal. (<b>B</b>) Bone marrow pDC produce less IFN-I in response to TLR-7/8 stimulation (R848) than blood pDC (non-infected macaques, n = 6) (<b>Left</b>). Most IFNα is produced by Ki67⁻ pDC and not by K67⁺ precursors (<b>Middle</b>). Representative dot plot showing that only Ki67⁻ pDC produce IFNα (<b>Right</b>). Wilcoxon's rank sum test was used for all comparisons of paired data.</p

Towards an Improved anti-HIV Activity of NRTI via Metal-Organic Frameworks Nanoparticles

Nanoscale mesoporous iron carboxylates metal-organic frameworks (nanoMOFs) have recently emerged as promising platforms for drug delivery, showing biodegradability, biocompatibility and important loading capability of challenging highly water-soluble drugs such as azidothymidine tryphosphate (AZT-TP). In this study, nanoMOFs made of iron trimesate (MIL-100) were able to act as efficient molecular sponges, quickly adsorbing up to 24 wt% AZT-TP with entrapment efficiencies close to 100%, without perturbation of the supramolecular crystalline organization. These data are in agreement with molecular modelling predictions, indicating maximal loadings of 33 wt% and preferential location of the drug in the large cages. Spectrophotometry, isothermal titration calorimetry, and solid state NMR investigations enable to gain insight on the mechanism of interaction of AZT and AZT-TP with the nanoMOFs, pointing out the crucial role of phosphates strongly coordinating with the unsaturated iron(III) sites. Finally, contrarily to the free AZT-TP, the loaded nanoparticles efficiently penetrate and release their cargo of active triphosphorylated AZT inside major HIV target cells, efficiently protecting against HIV infection

Plasmacytoid DC produce IFNα in both lymphoid and mucosal compartments.

<p>Dotplot showing IFNα intra-cellular staining in gated pDC (CD45⁺HLA-DR⁺lin⁻CD123⁺) in different tissues. Cells were labeled <i>ex vivo</i> on fresh cells after 30 min incubation in 10 µg/mL brefeldin A in the absence of any stimulation. Data for two macaques sacrificed on day 10 p.i. and one uninfected control are shown. Mononuclear cells from BM, spleen, peripheral LN, mesenteric LN, ileum, and colon were extracted for FACS analysis. Frequencies of IFNα-pDC are indicated in bold and # indicates the number of pDC recorded for each file.</p

Plasmacytoid DCs are major contributors of IFNα production in peripheral lymph nodes during primary infection.

<p>(<b>A</b>) Plasmacytoid DC frequencies among CD45⁺ PLN leukocytes on days 9 and 35 and month 3 post-infection (n = 6) and in uninfected macaques (n = 7). (<b>B</b>) IFNα-producing pDC in peripheral lymph nodes of 9 macaques at various times after infection as assessed by IFNα intracellular staining. Freshly isolated cells were labeled at various times after infection without any additional <i>in vitro</i> stimulation, after 30 min incubation in the presence of 10 mg/mL Brefeldin A. (<b>C</b>) Dotplots for two representative infected macaques (#30717, #30978) with fluorescence minus one (FMO) shown as a negative control (left). Dotplot showing intracellular IFNα expression in the total live CD45⁺ leukocyte gate for one representative infected macaque at day 9 p.i., and one representative uninfected macaque (right) (<b>D</b>). The percentage of IFNα⁺ pDC correlates with relative SIVgag mRNA expression in peripheral lymph nodes (day 9 p.i., n = 9). Spearman correlation. (<b>E</b>) Log₁₀ (relative IFNα mRNA expression) plotted against the percentage of IFNα expressing pDC in PLN (day 9 p.i., n = 9). Spearman correlation. Values at different time points were compared with the Wilcoxon rank sum test. When baseline values were not available, data for infected macaques were compared with uninfected macaques using the Mann-Whitney rank test; p values are given if the differences are statistically significant.</p

Plasmacytoid DCs in peripheral lymph nodes are strongly activated and are subject to a high death rate.

<p>(<b>A</b>) Analysis of CD40, CD86 and CD95 expression on pDC in lymph nodes of one representative uninfected macaque, and one representative infected macaque on day 9 and month 3 (M3) p.i. (<b>Top left</b>). SPICE analysis of CD40, CD86 and CD95 expressing pDC from 6 uninfected macaques and 6 infected macaques (day 9 and M3 p.i.) showing the distribution of each sub-population in total pDC as pie chart (n = 6) (<b>Bottom left</b>), and as bar chart (n = 6) (<b>right</b>) for each infection status. (<b>B</b>) Flow cytometry analysis of one animal sacrificed on day 10: CD40 and CD86 expression on gated pDC showing activated pDC with dual expression, and IFNα and CD86 expression. IFNα⁺ pDC are CD86^low/neg. (<b>C</b>) Histogram overlays of CD95 and staining of dead cells (Blue-Vid) in various tissues (BM for bone marrow, S for spleen, PLN for peripheral lymph nodes, MLN for mesenteric lymph nodes, AC for ascending colon) from one of two sacrificed macaques (red) and one uninfected control (black).</p