Non-infected Macrophages Research Articles

Combined Host-Pathogen Fate Mapping to Investigate Lung Macrophages in Viral Infection.

Macrophage identity, as defined by epigenetic, transcriptional, proteomic, and functional programs, is greatly impacted by cues originating from the microenvironment. As a consequence, immunophenotyping based on surface marker expression is established and reliable in homeostatic conditions, whereas environmental challenges, in particular infections, severely hamper the determination of identity states. This has become more evident with recent discoveries that macrophage-inherent plasticity may go beyond limits of lineage-defining immunophenotypes. Therefore, transgenic fate mapping tools, such as the phage-derived loxP-cre-system, are essential forthe analysis of macrophage adaptation in the tissue under extreme environmental conditions, for example, upon encounter with pathogens. In this chapter, we describe an advanced application of the loxP-cre-system during infection. Here, the host encodes a cell type-specific cre-recombinase, while the pathogen harbors a STOP-floxed fluorescent reporter gene. As an instructive example for the versatility of the system, we demonstrate that alveolar macrophages are predominantly targeted after respiratory tract infection with mouse cytomegalovirus (MCMV). Combined host-pathogen fate mapping not only enables to distinguish between infected and non-infected (bystander) macrophages but also spurs exploration of phenotypic adaptation and tracing of cellular localization in the context of MCMV infection. Moreover, we provide a gating strategy for resolving the diversity of pulmonary immune cell populations.

In vitro Evaluation of the Potent Antileishmanial Activity of Ferula tabasensis Alone or in Combination with Shark Cartilage Extract Against the Standard Iranian Strain of Leishmania major (MRHO/IR/75/ER).

The available drugs for the treatment of leishmaniasis are highly toxic and extremely expensive, with low efficiency; therefore, the development of effective therapeutic compounds is essential. The present study aimed to explore the antileishmanial effects of ethyl acetate extract, methanol extract, and fractions 1-4 (F1-F4) of Ferula tabasensis, alone or in combination with shark cartilage extract (ShCE), on L. major in vitro. In this study, ethyl acetate, methanol, and n-hexane extracts were extracted from the aerial roots of F. tabasensis by the maceration method. The silica gel column chromatography was used to separate n-hexane extracts at varying polarities (F1-F4 fractions). Subsequently, the effects of extracts and fractions against promastigotes were assessed by the parasite counting method microscopic inhibition test and MTT assay. Besides, their effects on the infected macrophage cells and the number of amastigotes were investigated. Cytotoxicity was evaluated in non-infected J774A.1 macrophage cells. Finally, apoptosis induction of promastigotes, including infected and non-infected macrophages, was evaluated. The results indicated the highly potent activity of F. tabasensis extracts and F1-F4 fractions, alone or in combination with ShCE, against L. major promastigotes and amastigotes in a dose-dependent manner (P < 0.05). The F1 fraction and methanol extract showed markedly higher toxicity compared to the other extracts and fractions, with 50% inhibitory concentrations (IC50/72h) of 2.4 ± 0.29 and 2.9 ± 0.55 µg/mL against promastigotes and 1.79 ± 0.27 µg/mL and 1.39 ± 0.27 µg/mL against amastigotes (P < 0.001). Moreover, they had a high selectivity index (SI) due to the low toxicity of macrophages (P < 0.0001). The results of flow cytometry indicated that the percentages of apoptotic promastigote cells in contact with IC50 concentrations of F1 and methanol extract alone after 72 h were 43.83 and 43.93%, as well as 78.4%, and 65.45% for their combination with ShCE, respectively.Also, apoptosis of infected macrophages induced by F1 and methanol extracts was estimated at 68.5% and 83.7%, respectively. In this study, the F1 fraction and methanol extract of F. tabasensis showed potent efficacy against L. major, associated with low toxicity and apoptosis induction. Therefore, they can be promising therapeutic candidates in future animal and even human studies.

Biochemical characterization and discrimination of Leishmania major parasites and infected macrophages with Raman spectroscopy and chemometrics

Leishmaniasis is classified as one of the neglected tropical disease (NTD), which are caused by a group of parasitic protozoans called Leishmania. The high case load and severity of the disease make Leishmaniasis second only to malaria in terms of both severity and infectivity. However, due to the low economic interest in research and development, it may become a major world-wide health threat. Current diagnostics including serological assessment of infected tissue by either light microscopy, or antibody tests or by the culturing of potential infection via in vitro or in vivo animal inoculation, parasitological tests using samples aspirated from the spleen and bone marrow, Immunological tests such as the Montenegro test, Fluorescence assays, and polymerase chain reaction (PCR) techniques are suffer from several limitations including time and expense. Herein, we first apply Raman microscopy to distinguish the two L. Major parasitic forms namely promastigotes and amastigotes and secondly, distinguish infected from non-infected macrophages using multivariate data analysis including Principal Component Analysis (PCA) and unsupervised hierarchical cluster imaging analysis (UHCA). The maximum variance between infected and uninfected macrophage groups are visible in the lipid region (92.20 %) as compared to the fingerprint region (46.13 %) along PC1. The contributions from nucleic acids can be found at 805 cm−1 (phosphodiester - Z-marker), 767 cm−1 (pyrimidine ring breathing mode), 742 cm−1 (ring breathing mode of DNA/RNA bases), and 568 cm−1 (cytosine/guanine). These amplified nucleic acid signals in infected macrophages indicate the presence of infection compared to the uninfected macrophage group. Similarly, the maximum variance between amastigotes and promastigotes groups are observed in the lipid region (88.45%) as compared to the fingerprint region (28.34 %). Moreover, the UHCA of infected macrophages revealed the accumulation of lipid bodies or droplets inside or close proximity parasitophorous vacuole, which is consistent with the reported literature. Once established macrophages were infected with Leishmania in vitro and the differences between infected and non-infected established with high reproducibility. The reported spectral differences between infected and non-infected macrophages lays the ground work for developing a diagnostic tool for detection of leishmaniasis in a buffy coat preparation and also offers the potential of monitoring the effects of new therapeutics.

Transcriptional changes associated with apoptosis and type I IFN underlie the early interaction between Besnoitia besnoiti tachyzoites and monocyte-derived macrophages

Besnoitia besnoiti-infected bulls may develop severe systemic clinical signs and orchitis that may ultimately cause sterility during the acute infection. Macrophages might play a relevant role in pathogenesis of the disease and the immune response raised against B. besnoiti infection. This study aimed to dissect the early interaction between B. besnoiti tachyzoites and primary bovine monocyte-derived macrophages in vitro. First, the B. besnoiti tachyzoite lytic cycle was characterized. Next, dual transcriptomic profiling of B. besnoiti tachyzoites and macrophages was conducted at early infection (4 and 8 h p.i.) by high-throughput RNA sequencing. Macrophages inoculated with heat-killed tachyzoites (MO-hkBb) and non-infected macrophages (MO) were used as controls. Besnoitia besnoiti was able to invade and proliferate in macrophages. Upon infection, macrophage activation was demonstrated by morphological and transcriptomic changes. Infected macrophages were smaller, round and lacked filopodial structures, which might be associated with a migratory phenotype demonstrated in other apicomplexan parasites. The number of differentially expressed genes (DEGs) increased substantially during infection. In B. besnoiti-infected macrophages (MO-Bb), apoptosis and mitogen-activated protein kinase (MAPK) pathways were regulated at 4 h p.i., and apoptosis was confirmed by TUNEL assay. The Herpes simplex virus 1 infection pathway was the only significantly enriched pathway in MO-Bb at 8 h p.i. Relevant DEGs of the Herpes simplex virus 1 infection (IFNα) and the apoptosis pathways (CHOP-2) were also significantly regulated in the testicular parenchyma of naturally infected bulls. Furthermore, the parasite transcriptomic analysis revealed DEGs mainly related to host cell invasion and metabolism. These results provide a deep overview of the earliest macrophage modulation by B. besnoiti that may favour parasite survival and proliferation in a specialized phagocytic immune cell. Putative parasite effectors were also identified.

Reduced phagocytic activity of human alveolar macrophages infected with Mycobacterium avium complex

IntroductionCo-infection of nontuberculous mycobacteria (NTM) with other bacteria is associated with increased frequency of hospitalization and reduced quality of life. However, the clinical significance of co-infection with NTM and other bacteria remains unclear. Here, we investigated the distribution of alveolar macrophage populations, characterized their phagocytic function in bronchoalveolar lavage fluid (BALF), and assessed the bactericidal function of macrophages infected with NTM using cell lines. MethodsBALF samples were prospectively obtained from 30 patients with suspected NTM lung disease to evaluate phagocytic activities of macrophages using immunostaining. Bactericidal activities of Staphylococcus aureus (S. aureus) and Mycobacterium intracellulare (M. intracellulare)-infected or -non-infected macrophages were evaluated using macrophage cell lines. ResultsEleven patients with Mycobacterium avium complex (MAC) infection and 19 patients with chronic lower respiratory tract infections except for NTM infection (controls) were enrolled. The percentage of non-polarized (HLA-DR+, CD40−, and CD163−) macrophages in patients infected with MAC was significantly higher than that in controls; non-polarized macrophages demonstrated an impaired ability to phagocytose S. aureus. In vitro experiments revealed higher intracellular S. aureus colony-forming unit counts and proinflammatory cytokine levels in M. intracellulare-infected macrophages than in non-NTM-infected macrophages. Electron microscopy showed morphologically damaged macrophages and M. intracellulare and S. aureus growing in the same phagosome. ConclusionThe proportion of alveolar macrophages (HLA-DR+, CD40−, and CD163−) with impaired phagocytosis increased in MAC-infected individuals. M. intracellulare-infected macrophages reduced bactericidal activity in vitro. Dysfunction of alveolar macrophages may contribute to persistent infection by other bacteria, leading to MAC lung disease progression.

Novel dual-fluorescent flow cytometric approach for quantification of macrophages infected with Leishmania infantum parasites.

Flow cytometry analysis emerges as an alternative methodology to microscopy for determination of the Leishmania-infection rates of macrophages. Various flow cytometric approaches have been established for the quantification of Leishmania parasites within host cells, labelled either directly fluorescent dyes or indirectly with fluorescently conjugated antibodies. Although these techniques allow accurate quantification of infection, they fail at detection of non-infected macrophages specifically. This study introduces a new flow cytometric approach for the determination of infection rates of macrophages infected by Leishmania infantum parasites. Prior to infection, J774A.1 macrophages and L. infantum promastigotes were stained separately with PKH26 and PKH67 dyes, respectively. Dual staining enabled detection of each cell type, where non-infected macrophages were also recorded for the quantification. Dual-PKH staining achieved high success in selective staining of promastigotes (99.71%) and macrophages (99.57%). The percentages of parasite-infected macrophages were determined for initial 1:2.5 and 1:10 infection ratios as 15.68 and 61.70%, respectively; indicating significant increase in infection rate parallel to the initial treatment ratio. These results demonstrated that the introduced dual-fluorescence flow cytometric approach can be successfully used as an accurate and rapid quantification method for L. infantum-infected macrophages and strengthens the hypothesis that flow cytometric approaches could replace conventional microscopic methodologies.

Toll-like receptor-7/8 agonist kill Leishmania amazonensis by acting as pro-oxidant and pro-inflammatory agent.

Evaluation of the anti-Leishmanial activity of imidazoquinoline-based TLR7/8 agonists. TLR7/8-active imidazoquinolines (2 and 3) were synthesized and assessed for activity against Leishmania amazonensis-intracellular amastigotes using mouse peritoneal macrophages. The production of reactive oxygen species (ROS), nitric oxide (NO) and cytokines was determined in infected and non-infected macrophages. The imidazoquinolines, 2 and 3, were primarily agonists of TLR7 with compound 3 also showing modest TLR8 activity. Docking studies showed them to occupy the same binding pocket on TLR7 and 8 as the known agonists, imiquimod and resiquimod. Compounds 2 and 3 inhibited the growth of L. amazonensis-intracellular amastigotes with the most potent compound (3, IC50 = 5.93 µM) having an IC50 value close to miltefosine (IC50 = 4.05 µM), a known anti-Leishmanial drug. Compound 3 induced macrophages to produce ROS, NO and inflammatory cytokines that likely explain the anti-Leishmanial effects. This study shows that activating TLR7 using compounds 2 or 3 induces anti-Leishmanial activity associated with induction of free radicals and inflammatory cytokines able to kill the parasites. While 2 and 3 had a very narrow cytotoxicity window for macrophages, this identifies the possibility to further develop this chemical scaffold to less cytotoxic TLR7/8 agonist for potential use as anti-Leishmanial drug.

Investigating in Vivo and in Vitro Effects of Ethanolic and Aqueous Extracts of Myrtle (Myrtus communis) on Leishmania major.

Background:The extract of myrtle plant contains polyphenolic compounds that show antibacterial, antiviral, and anti-parasitic properties. We aimed to investigate the therapeutic effect of aqueous and ethanolic myrtle extract against leishmaniasis caused by L. major in vivo and in vitro conditions.Methods:This study was carried out in Tarbiat Modares University, Tehran, Iran in 2018. Aqueous and ethanolic extract of myrtle plant at 6.25 to 400 mg/ml concentrations were tested on Leishmania major promastigotes, non-infected macrophages, and macrophages infected with amastigotes in vitro using counting, MTT and flow cytometry techniques. Then, BALB/c mice were treated with ethanolic, aqueous and a mixture of both extracts of myrtle plant. The treatment was carried out for four weeks. Then, the effectiveness of the herbal medicine was assessed by measuring wounds diameters, mice weights and their mortality rate on weekly basis.Results:The IC50 values of aqueous and ethanolic extracts for promastigotes were 7.86 and 11.66 μg/mL respectively. The IC50 values of the aqueous and ethanolic extracts for amastigotes were 12.5 and 47.2 μg/mL respectively. Flow cytometry indicates 62.88% and 60.16% apoptosis induced by ethanolic and aqueous extract of myrtle plant respectively. The lowest parasitic load was seen in the group treated with ethanolic extract.Conclusion:The lesion sizes for treated groups with extracts were similar to those treated with glucantime. Oral administration instead of injection is another advantage of myrtle plant over glucantime, which makes the herb easy and more practical.

Dicentracin-Like from Asian sea bass Fish and Moronecidine-Like from Hippocampus Comes: Two Candidate Antimicrobial Peptides Against Leishmanina major Infection

Anti-Leishmanial drug therapy faces significant challenges related to cytotoxicity and drug resistance. Thus, new and efficient anti-Leishmanial drugs need to be identified. Due to their broad-spectrum antimicrobial and also immunomodulatory activities, antimicrobial peptides (AMPs) have attracted considerable attention. In this study, we comparatively assessed the anti-Leishmanial activities of two recently identified AMPs (dicentracin-like and moronecidine-like) and the well-known AMP piscidin from the hybrid striped bass. AMPs were first assessed against Leishmania major promastigotes using MTS. Subsequently, macrophages were infected with L. major and treated with AMPs to evaluate anti-amastigotes activity of AMPs, and non-infected macrophages were treated with AMPs to determine cytotoxicity against mammalian cells using MTS. The induction of factors limiting L. major growth (IL-12, TNF-α and reactive oxygen species (ROS)) by AMPs was measured by ELISA and dichlorofluorescin-diacetate (DCFH-DA) assay, respectively. Piscidin was more efficacious against L. major promastigotes as compared to dicentracine-like or moronocidin-like peptides, whereas, dicentracine-like and moronocidin-like peptide exhibited a higher activity against L. major amastigotes compared to piscidin. In turn, piscidin was most cytotoxic in non-infected macrophages compared to the other two AMPs. A direct association was observed between hydrophobicity of AMPs and their anti-promastigote and cytotoxic activities. Dicentracine-like or moronocidin-like peptides induced higher levels of IL-12, TNF-α and ROS in macrophages compared to piscidin. Collectively, our results suggest that dicentracine-like and moronocidin-like peptides represent potentially promising multi-functional therapeutic agents that might not only directly kill L. major but also induce anti-Leishmania factors that can limit L. major growth and intracellular survival.

Encephalitozoon intestinalis Infection Impacts the Expression of Apoptosis-Related Genes in U937 Macrophage Cells.

Encephalitozoon intestinalis affects many physiological processes of host cells to survive, proliferate, and spread to different regions within the body. In this study, the effects of the parasite on host cell apoptosis and proliferation were investigated. To determine the impact of the parasite on the host cell apoptosis, changes in the expression profile of genes were investigated with the qPCR array using the Human Apoptosis Panel in infected and non-infected macrophage cells. Also, the rate of apoptosis in the cells was determined by Giemsa staining method. Cell proliferation was determined by measuring the DNA concentration in infected and non-infected cells. The thirty-six of apoptosis-related genes were down-regulated, while 20 of apoptosis-related genes were up-regulated in infected cells compared to uninfected cells. However, there were no significant changes detected in 32 analyzed genes between infected and control groups. E. intestinalis was determined to decrease cell proliferation in U937 macrophage cells. Unexpectedly, Giemsa staining showed an increase in the rate of apoptosis in infected cells. Regulated genes after infection are involved in many different biological pathways and various components of the cell. This suggests that the parasite uses highly sophisticated ways to maintain the viability of the cell.

Mannose-Decorated Dendritic Polyglycerol Nanocarriers Drive Antiparasitic Drugs To Leishmania infantum-Infected Macrophages

Macrophages are hosts for intracellular pathogens involved in numerous diseases including leishmaniasis. They express surface receptors that may be exploited for specific drug-targeting. Recently, we developed a PEGylated dendritic polyglycerol-based conjugate (PG–PEG) that colocalizes with intracellular parasite. We hereby study the effect of surface decoration with mannose units on the conjugates’ targeting ability toward leishmania intracellular parasites. Murine and human macrophages were exposed to fluorescently labeled mannosylated PG–PEG and uptake was quantified by flow cytometry analysis. Nanocarriers bearing five mannose units showed the highest uptake, which varied between 30 and 88% in the population in human and murine macrophages, respectively. The uptake was found to be dependent on phagocytosis and pinocytosis (80%), as well as clathrin-mediated endocytosis (79%). Confocal microscopy showed that mannosylated PG–PEGs target acidic compartments in macrophages. In addition, when both murine and human macrophages were infected and treated, colocalization between parasites and mannosylated nanoconjugates was observed. Leishmania-infected bone marrow-derived macrophages (BMM) showed avidity by mannosylated PG–PEG whereas non-infected macrophages rarely accumulated conjugates. Moreover, the antileishmanial activity of Amphotericin B was kept upon conjugation to mannosylated PG–PEG through a pH-labile linker. This study demonstrates that leishmania infected macrophages are selectively targeted by mannosylated PEGylated dendritic conjugates.

Immunometabolism of Leishmania granulomas.

Leishmania are parasitic protists that cause a spectrum of diseases in humans characterized by the formation of granulomatous lesions in the skin or other tissues, such as liver and spleen. The extent to which Leishmania granulomas constrain or promote parasite growth is critically dependent on the host T-helper type 1/T-helper type 2 immune response and the localized functional polarization of infected and noninfected macrophages toward a classically (M1) or alternatively (M2) activated phenotype. Recent studies have shown that metabolic reprograming of M1 and M2 macrophages underpins the capacity of these cells to act as permissive or nonpermissive host reservoirs, respectively. In this review, we highlight the metabolic requirements of Leishmania amastigotes and the evidence that these parasites induce and/or exploit metabolic reprogramming of macrophage metabolism. We also focus on recent studies highlighting the role of key macrophage metabolic signaling pathways, such as mechanistic target of rapamycin, adenosine monophosphate-activated protein kinase and peroxisome proliferator receptor gamma in regulating the pathological progression of Leishmania granulomas. These studies highlight the intimate connectivity between Leishmania and host cell metabolism, the need to investigate these interactions in vivo and the potential to exploit host cell metabolic signaling pathways in developing new host-directed therapies.

Phylloseptin-1 is Leishmanicidal for Amastigotes of Leishmaniaamazonensis Inside Infected Macrophages.

Leishmania protozoans are the causal agents of neglected diseases that represent an important public health issue worldwide. The growing occurrence of drug-resistant strains of Leishmania and severe side effects of available treatments represent an important challenge for the leishmaniases treatment. We have previously reported the leishmanicidal activity of phylloseptin-1 (PSN-1), a peptide found in the skin secretion of Phyllomedusa azurea (=Pithecopus azureus), against Leishmania amazonensis promastigotes. However, its impact on the amastigote form of L. amazonensis and its impact on infected macrophages are unknown. In this work, we evaluated the effects of PSN-1 on amastigotes of L. amazonensis inside macrophages infected in vitro. We assessed the production of hydrogen peroxide and nitric oxide, as well as the levels of inflammatory and immunomodulatory markers (TGF-β, TNF-α and IL-12), in infected and non-infected macrophages treated with PSN-1. Treatment with PSN-1 decreased the number of infected cells and the number of ingested amastigotes per cell when compared with the untreated cells. At 32 µM (64 µg/mL), PSN-1 reduced hydrogen peroxide levels in both infected and uninfected macrophages, whereas it had little effect on NO production or TGF-β release. The effect of PSN-1 on IL-12 and TNF-α secretion depended on its concentration, but, in general, their levels tended to increase as PSN-1 concentration increased. Further in vitro and in vivo studies are needed to clarify the mechanisms of action of PSN-1 and its interaction with the immune system aiming to develop pharmacological applications.

Comparative Expression Profile Analysis of Apoptosis-Related miRNA and Its Target Gene in Leishmania major Infected Macrophages.

Background:Cutaneous Leishmaniasis (CL) is an emerging uncontrollable and neglected infectious disease worldwide including Iran. The aim of this study was to investigate the expression profile of apoptosis-related miRNA and its target gene in macrophages.Methods:This study was carried out in the Department of Medical Parasitology and Mycology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran from January 2016 to November 2018. Applying literature reviews, bioinformatics software, and microarray expression analysis, we selected miRNA-24-3p interfering in apoptosis pathway. The expression profile of this miRNA and target gene were investigated in Leishmania major (MRHO/IR/75/ER)-infected primary and RAW 264.7 macrophages (IBRC-C10072) compared with non-infected macrophages (control group) using quantitative Real-time PCR.Results:Results of bioinformatics analysis showed that miR-24-3p as anti-apoptotic miRNA inhibits pro-apoptotic genes (Caspases 3 and 7). Microarray expression data presented in Gene Expression Omnibus (GEO) revealed a significant difference in the expression level of selected miRNA and its target gene between two groups. QRT-PCR results showed that the expression of miR-24-3p was upregulated in L. major infectioned macrophages that approved the results of bioinformatics and microarray analysis.Conclusion:Parasite can alter miRNAs expression pattern in the host cells to establish infection and its survival. Alteration in miRNAs levels likely plays an important role in regulating macrophage functions following L. major infection. These results could highlight current understanding and new insights concerning the gene expression in macrophages during leishmaniasis and will help to development of novel strategies for control and treatment of CL.

Macrophage ghost entrapped amphotericin B: a novel delivery strategy towards experimental visceral leishmaniasis

Leishmania donovani, an intracellular parasite, poses many challenges against attempted chemotherapy. After the resistance towards the first-line antileishmanial drug, amphotericin B has become the treatment of choice against visceral leishmaniasis, a fatal tropical disease. However, unfavorable toxicity profile, severe side effects, and prolonged parenteral administration limit its use. Lack of available specific delivery system also makes this drug unsafe for long-term use. In the current study, a "ghost cell" strategy based on macrophage membrane-derived nanovesicle has been introduced as a specific carriage for amphotericin B. Membrane proteins of macrophage ghost play a crucial role in the dissemination of infection in host by communicating between infected neutrophil-macrophage system and non-infected macrophages. These membrane proteins are the basis of specificity of the drug delivery to the infected tissues in this current macrophage ghost cell carrier. This cheap and biocompatible delivery vehicle has significantly improved the toxicity profile and lowered LD50 value of the drug compared to traditional way of its direct administration and widely accepted antileishmanial therapy, AmBisome.

Induction of HIF-1α by HIV-1 Infection in CD4+ T Cells Promotes Viral Replication and Drives Extracellular Vesicle-Mediated Inflammation.

Chronic immune activation and inflammation are hallmarks of HIV-1 infection and a major cause of serious non-AIDS events in HIV-1-infected individuals on antiretroviral treatment (ART). Herein, we show that cytosolic double-stranded DNA (dsDNA) generated in infected CD4+ T cells during the HIV-1 replication cycle promotes the mitochondrial reactive oxygen species (ROS)-dependent stabilization of the transcription factor hypoxia-inducible factor 1α (HIF-1α), which in turn, enhances viral replication. Furthermore, we show that induction of HIF-1α promotes the release of extracellular vesicles (EVs). These EVs foster inflammation by inducing the secretion of gamma interferon by bystander CD4+ T cells and secretion of interleukin 6 (IL-6) and IL-1β by bystander macrophages through an HIF-1α-dependent pathway. Remarkably, EVs obtained from plasma samples from HIV-1-infected individuals also induced HIF-1α activity and inflammation. Overall, this study demonstrates that HIF-1α plays a crucial role in HIV-1 pathogenesis by promoting viral replication and the release of EVs that orchestrate lymphocyte- and macrophage-mediated inflammatory responses.IMPORTANCE Human immunodeficiency virus type 1 (HIV-1) is a very important global pathogen that preferentially targets CD4+ T cells and causes acquired immunodeficiency syndrome (AIDS) if left untreated. Although antiretroviral treatment efficiently suppresses viremia, markers of immune activation and inflammation remain higher in HIV-1-infected patients than in uninfected individuals. The hypoxia-inducible factor 1α (HIF-1α) is a transcription factor that plays a fundamental role in coordinating cellular metabolism and function. Here we show that HIV-1 infection induces HIF-1α activity and that this transcription factor upholds HIV-1 replication. Moreover, we demonstrate that HIF-1α plays a key role in HIV-1-associated inflammation by promoting the release of extracellular vesicles which, in turn, trigger the secretion of inflammatory mediators by noninfected bystander lymphocytes and macrophages. In summary, we identify that the coordinated actions of HIF-1α and extracellular vesicles promote viral replication and inflammation, thus contributing to HIV-1 pathogenesis.

In vitro antileishmanial effects of Physalis angulata root extract on Leishmania infantum

ObjectiveIn the present study, we evaluated the effects of the aqueous extract of Physalis angulata root (AEPa) on Leishmania infantum proliferation, morphology, and the driving mechanism in leishmanicidal activity and modulatory action on macrophages. MethodsL. infantum promastigotes were treated with 50 and 100 µg/mL AEPa for 72 h and then antipromastigote assay was performed by counts in a Newbauer chamber, morphological changes were analyzed by transmission electron microscopy and the mechanism of the leishmanicidal activity was detected. In addition, macrophages were infected with L. infantum and were used to evaluate anti-amastigote activity of AEPa and effects of AEPa on cytokine secretion after 72-hour treatment. ResultsTreatment with AEPa reduced the numbers of L. infantum promastigotes (50% inhibitory concentration (IC50) = 65.9 μg/mL; selectivity index (SI) = 22.1) and amastigotes (IC50 = 37.9 μg/mL; SI = 38.5) compared with the untreated control. Amphotericin B reduced 100% of the promastigote numbers after 72 h of treatment (IC50 = 0.2 μg/mL). AEPa induced several morphological changes and increased the production of reactive oxygen species and apoptotic death in promastigotes after treating for 72 h. AEPa (100 μg/mL) promoted tumor necrosis factor-α secretion in macrophages infected with L. infantum after 72 h of treatment, but did not induce an increase in this cytokine in noninfected macrophages. In addition, AEPa showed no cytotoxic effect on J774-A1 cells (50% cytotoxic concentration >1000 μg/mL). ConclusionAEPa presented antileishmanial activity against the promastigotes and amastigotes of L. infantum without macrophage cytotoxicity; these results show that natural products such as P. angulata have leishmanicidal potential and in the future may be an alternative treatment for leishmaniasis.

Impact of Leishmania donovani infection on the HLA I self peptide repertoire of human macrophages.

Macrophages are specialized antigen-presenting cells that process and present self-antigens for induction of tolerance, and foreign antigens to initiate T cell-mediated immunity. Despite this, Leishmania donovani (LD) are able to parasitize the macrophages and persist. The impact of this parasitizing and persistence on antigen processing and presentation by macrophages remains poorly defined. To gain insight into this, we analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and compared the HLA-I self-peptidomes, proteasome compositions, HLA expression and activation states of non-infected and LD-infected THP1-derived macrophages. We found that, though both HLA-I peptidomes were dominated by nonapeptides, they were heterogeneous and individualized, with differences in HLA binding affinities and anchor residues. Non-infected and LD-infected THP1-derived macrophages were able to sample peptides from source proteins of almost all subcellular locations and involved in various cellular functions, but in different proportions. In the infected macrophages, there was increased sampling of plasma membrane and extracellular proteins, and those involved in immune responses, cell communication/signal transduction and metabolism/energy pathways, and decreased sampling of nuclear and cytoplasmic proteins and those involved in protein metabolism, RNA binding and cell growth and/or maintenance. Though the activation state of infected macrophages was unchanged, their proteasome composition was altered.

Role of exosomes as a proinflammatory mediator in the development of EBV-associated lymphoma

AbstractEpstein-Barr virus (EBV) causes various diseases in the elderly, including B-cell lymphoma such as Hodgkin's lymphoma and diffuse large B-cell lymphoma. Here, we show that EBV acts in trans on noninfected macrophages in the tumor through exosome secretion and augments the development of lymphomas. In a humanized mouse model, the different formation of lymphoproliferative disease (LPD) between 2 EBV strains (Akata and B95-8) was evident. Furthermore, injection of Akata-derived exosomes affected LPD severity, possibly through the regulation of macrophage phenotype in vivo. Exosomes collected from Akata-lymphoblastoid cell lines reportedly contain EBV-derived noncoding RNAs such as BamHI fragment A rightward transcript (BART) micro-RNAs (miRNAs) and EBV-encoded RNA. We focused on the exosome-mediated delivery of BART miRNAs. In vitro, BART miRNAs could induce the immune regulatory phenotype in macrophages characterized by the gene expressions of interleukin 10, tumor necrosis factor-α, and arginase 1, suggesting the immune regulatory role of BART miRNAs. The expression level of an EBV-encoded miRNA was strongly linked to the clinical outcomes in elderly patients with diffuse large B-cell lymphoma. These results implicate BART miRNAs as 1 of the factors regulating the severity of lymphoproliferative disease and as a diagnostic marker for EBV+ B-cell lymphoma.

The effect of Ebola Virus secreted glycoprotein on activated macrophages.

Abstract During Ebola virus (EBOV) infection, secreted glycoprotein (sGP) and viral protein 40 (VP40) are found in large quantities in the serum of infected animals. Studies suggest that sGP only provides passive immunity by serving as a decoy to anti-EBOV antibodies, and no role for soluble VP40 has been determined. Using an in vitro model incorporating treatment of THP-1 macrophages with recombinant EBOV sGP and recombinant VP40, we examined the impact of the viral proteins upon key macrophage functions. Treatment with sGP inhibited macrophage production of pro-inflammatory cytokines (TNFα and IL-6) while the yield of anti-inflammatory cytokine (IL-10) remains unaltered. In contrast, VP40 seems to increase the production of pro-inflammatory cytokines. Furthermore, sGP affected only the function of activated macrophages and not the polarization. Phagocytic capacity was unaffected by sGP. Interestingly, the migratory ability of macrophages was diminished by sGP, and cell viability was increased, potentially due to a decrease in expression of CD11b, a vital macrophage integrin. Thus, the results suggests that while EBOV VP40 increases anti-viral immunity, EBOV sGP may operate to diminish functional contributions of non-infected macrophages for the purpose of increasing the potential viral dissemination between macrophages. Previously macrophages were activated utilizing a TLR4 agonist, LPS. TLR2 agonist zymosan, TLR3 agonist HMW Poly (I:C), TLR7 agonist imiquimod, and TLR9 agonist Class C CpG were examined. Further directions include determining the mechanism behind the inhibition and the specific TLR pathway molecules that are affected by sGP treatment.