Preformed Membrane-Associated Stores of Interleukin (Il)-12 Are a Previously Unrecognized Source of Bioactive IL-12 That Is Mobilized within Minutes of Contact with an Intracellular Parasite

The prevailing paradigm is that production of the interleukin (IL)-12 p70 heterodimer, a critical T helper cell type 1 (Th1)–inducing cytokine, depends on the induced transcription of the p40 subunit. Concordant with this paradigm, we found that dendritic cells (DCs) produced IL-12 p70 only after at least 2–4 h of stimulation with lipopolysaccharide plus interferon γ. However, using several complementary experimental approaches, including electron and confocal microscopy, we now show that resting murine and human myeloid cells, including macrophages/DCs and DC-rich tissues, contain a novel source of bioactive IL-12 that is preformed and membrane associated. These preformed, membrane-associated IL-12 p70 stores are released within minutes after in vitro or in vivo contact with Leishmania donovani, an intracellular pathogen. Our findings highlight a novel source of bioactive IL-12 that is readily available for the rapid initiation of Th1 host responses to pathogens such as Leishmania species.

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In Vitro and In Vivo Activities of a Triterpenoid Saponin Extract (PX-6518) from the Plant Maesa balansae against Visceral Leishmania Species

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.48.1.130-136.2004 ◽

2004 ◽

Vol 48 (1) ◽

pp. 130-136 ◽

Cited By ~ 59

Author(s):

Louis Maes ◽

Dirk Vanden Berghe ◽

Nils Germonprez ◽

Ludo Quirijnen ◽

Paul Cos ◽

...

Keyword(s):

Leishmania Donovani ◽

Human Fibroblasts ◽

Subcutaneous Administration ◽

Leishmania Species ◽

Host Cells ◽

Triterpenoid Saponin ◽

Sodium Stibogluconate ◽

Triterpenoid Saponins

ABSTRACT The in vitro and in vivo activities of a mixture of six oleane triterpene saponins, recovered from the methanolic extract of the leaves of the Vietnamese plant Maesa balansae (PX-6518), were evaluated against drug-sensitive visceral Leishmania strains. The in vitro 50% inhibitory concentration (IC50) against intracellular Leishmania infantum amastigotes was 0.04 μg/ml. The cytotoxic concentrations causing 50% cell death (CC50s) were about 1 μg/ml in murine macrophage host cells and >32 μg/ml in human fibroblasts (MRC-5 cell line). Evaluation in the Leishmania donovani BALB/c mouse model indicated that a single subcutaneous administration of 0.4 mg/kg at 1 day after infection reduced liver amastigote burdens by about 95% in all treated animals. If treatment was delayed until 14 days after infection, a dose of 1.6 mg/kg of body weight was required to maintain the same level of activity. Single 250-mg/kg doses of sodium stibogluconate (Pentostam) 1 and 14 days after infection produced comparable efficacies. A single dose of PX-6518 at 2.5 mg/kg administered 5 days before infection was still 100% effective in preventing liver infection, suggesting a particularly long residual action. Spleen and bone marrow could not be cleared by PX-6518 nor sodium stibogluconate. PX-6518 did not show activity after oral dosing at up to 200 mg/kg for 5 days. This study concludes that triterpenoid saponins from M. balansae show promising in vitro and in vivo antileishmanial potential and can be considered as new lead structures in the search for novel antileishmanial drugs.

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Delivery of Interferon-γ by an adenovirus vector blocks herpes simplex virus Type 1 reactivation in vitro and in vivo independent of RNase L and double-stranded RNA-dependent protein kinase pathways

Journal of Neuroimmunology ◽

10.1016/j.jneuroim.2008.10.008 ◽

2009 ◽

Vol 206 (1-2) ◽

pp. 39-43 ◽

Cited By ~ 9

Author(s):

Daniel J.J. Carr ◽

Bobbie A. Austin ◽

William P. Halford ◽

Patrick M. Stuart

Keyword(s):

Adenovirus Vector ◽

Interferon Γ ◽

Rnase L ◽

Dependent Protein Kinase ◽

Double Stranded Rna ◽

Dependent Protein ◽

Simplex Virus

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Differential Regulation of DAP12 and Molecules Associated with DAP12 during Host Responses to Mycobacterial Infection

Infection and Immunity ◽

10.1128/iai.72.5.2477-2483.2004 ◽

2004 ◽

Vol 72 (5) ◽

pp. 2477-2483 ◽

Cited By ~ 34

Author(s):

Naoko Aoki ◽

Anna Zganiacz ◽

Peter Margetts ◽

Zhou Xing

Keyword(s):

Mycobacterial Infection ◽

Host Responses ◽

Necrosis Factor Alpha ◽

Lung Macrophage ◽

Tnf Α ◽

Kinetic Expression ◽

Ifn Γ

ABSTRACT DAP12 and its associating molecules MDL-1, TREM-1, and TREM-2 are the recently identified immune regulatory molecules, expressed primarily on myeloid cells including monocytes/macrophages, dendritic cells, NK cells, and neutrophils. However, little is known about the regulation of their expression during host antimicrobial responses. We have investigated the effect of pulmonary mycobacterial infection and type 1 cytokines on the expression of these molecules both in vivo and in vitro. While DAP12 was constitutively expressed at high levels in the lungs, the MDL-1, TREM-1, and TREM-2 molecules were inducible during mycobacterial infection. Their kinetic expression was correlated with that of the type 1 cytokines tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ). In primary lung macrophage cultures, high constitutive levels of DAP12 and TREM-2 were not modulated by mycobacterial or type 1 cytokine exposure. In contrast, expression of both MDL-1 and TREM-1 was markedly induced by mycobacterial infection and such induction was inhibited by concurrent exposure to IFN-γ. On mycobacterial infection of TNF-α−/− and IFN-γ−/− mice in vivo or their lung macrophages in vitro, TNF-α was found to be critical for mycobacterially induced MDL-1, but not TREM-1, expression whereas IFN-γ negatively regulated mycobacterially induced MDL-1 and TREM-1 expression. Our findings thus suggest that DAP12 and its associating molecules are differentially regulated by mycobacterial infection and type 1 cytokines and that MDL-1- and TREM-1-triggered DAP12 signaling may play an important role in antimicrobial type 1 immunity.

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N-Chlorotaurine shows high in vitro activity against promastigotes and amastigotes of Leishmania species

Journal of Medical Microbiology ◽

10.1099/jmm.0.011155-0 ◽

2009 ◽

Vol 58 (10) ◽

pp. 1298-1302 ◽

Cited By ~ 4

Author(s):

Ursula Fürnkranz ◽

Markus Nagl ◽

Waldemar Gottardi ◽

Ulrich Matt ◽

Horst Aspöck ◽

...

Keyword(s):

Leishmania Donovani ◽

Leishmania Species ◽

Protozoan Parasites ◽

First Line ◽

Mucocutaneous Leishmaniasis ◽

Causative Agents ◽

Life Threatening ◽

Susceptibility Tests

Protozoan parasites of the genus Leishmania are the causative agents of life-threatening visceral as well as cutaneous and mucocutaneous leishmaniasis. First-line drugs are antimonials, but toxicity and resistance in some endemic areas cause serious problems. In the current study, the antileishmanial activity of the weak oxidant N-chlorotaurine (NCT) was investigated. NCT is a derivative of the amino acid taurine produced by granulocytes and monocytes during oxidative burst, but can also be synthesized chemically and used topically as an antiseptic at a concentration of 1 % (55 mM) in vivo. NCT susceptibility tests were performed in vitro with promastigotes and amastigotes of Leishmania infantum and Leishmania donovani. As NH4Cl is known to increase the activity of NCT by the formation of monochloramine (NH2Cl), co-treatment assays were included in the study. Mean EC50 values after 1 h of treatment were 5.94 mM for L. infantum and 9.8 mM for L. donovani promastigotes. Co-treatment with 5.5 mM NCT plus 19 mM NH4Cl led to complete killing of promastigotes of both strains within 15 min. Amastigotes were inactivated by treatment with 2 mM NCT alone. The results of this study indicate a high potential of NCT against Leishmania species.

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Interleukin 12–dependent Interferon γ Production by CD8α+Lymphoid Dendritic Cells

Journal of Experimental Medicine ◽

10.1084/jem.189.12.1981 ◽

1999 ◽

Vol 189 (12) ◽

pp. 1981-1986 ◽

Cited By ~ 246

Author(s):

Toshiaki Ohteki ◽

Taro Fukao ◽

Kazutomo Suzue ◽

Chikako Maki ◽

Mamoru Ito ◽

...

Keyword(s):

Dendritic Cells ◽

Nk Cell ◽

Interferon Γ ◽

Interleukin 12 ◽

Helper Cell Type ◽

Ifn Γ ◽

Antigen Presenting

We investigated the role of antigen-presenting cells in early interferon (IFN)-γ production in normal and recombinase activating gene 2–deficient (Rag-2−/−) mice in response to Listeria monocytogenes (LM) infection and interleukin (IL)-12 administration. Levels of serum IFN-γ in Rag-2−/− mice were comparable to those of normal mice upon either LM infection or IL-12 injection. Depletion of natural killer (NK) cells by administration of anti-asialoGM1 antibodies had little effect on IFN-γ levels in the sera of Rag-2−/− mice after LM infection or IL-12 injection. Incubation of splenocytes from NK cell–depleted Rag-2−/− mice with LM resulted in the production of IFN-γ that was completely blocked by addition of anti–IL-12 antibodies. Both dendritic cells (DCs) and monocytes purified from splenocytes were capable of producing IFN-γ when cultured in the presence of IL-12. Intracellular immunofluorescence analysis confirmed the IFN-γ production from DCs. It was further shown that IFN-γ was produced predominantly by CD8α+ lymphoid DCs rather than CD8α− myeloid DCs. Collectively, our data indicated that DCs are potent in producing IFN-γ in response to IL-12 produced by bacterial infection and play an important role in innate immunity and subsequent T helper cell type 1 development in vivo.

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Naphthoquinones and derivatives for chemotherapy: perspectives and limitations of their anti-trypanosomatids activities

Current Pharmaceutical Design ◽

10.2174/1381612826666201109111802 ◽

2020 ◽

Vol 26 ◽

Author(s):

Luíza Dantas-Pereira ◽

Edézio F. Cunha-Junior ◽

Valter V. Andrade-Neto ◽

John F. Bower ◽

Guilherme A. M. Jardim ◽

...

Keyword(s):

Large Scale ◽

Neglected Tropical Diseases ◽

Folk Medicine ◽

Leishmania Species ◽

Parasitic Infections ◽

Mechanistic Analysis ◽

Leishmania Spp ◽

Nanomolar Range

: Chagas disease, Sleeping sickness and Leishmaniasis, caused by trypanosomatids Trypanosoma cruzi, Trypanosoma brucei and Leishmania spp., respectively, are considered neglected tropical diseases, and they especially affect impoverished populations in the developing world. The available chemotherapies are very limited and a search for alternatives is still necessary. In folk medicine, natural naphthoquinones have been employed for the treatment of a great variety of illnesses, including parasitic infections. This review is focused on the anti-trypanosomatid activity and mechanistic analysis of naphthoquinones and derivatives. Among all the series of derivatives tested in vitro, naphthoquinone-derived 1,2,3-triazoles were very active on T. cruzi infective forms in blood bank conditions, as well as in amastigotes of Leishmania spp. naphthoquinones containing a CF3 on a phenyl amine ring inhibited T. brucei proliferation in the nanomolar range, and naphthopterocarpanquinones stood out for their activity on a range of Leishmania species. Some of these compounds showed a promising selectivity index (SI) (30 to 1900), supporting further analysis in animal models. Indeed, high toxicity to the host and inactivation by blood components are crucial obstacles to be overcome to use naphthoquinones and/or their derivatives for chemotherapy. Multidisciplinary initiatives embracing medicinal chemistry, bioinformatics, biochemistry, and molecular and cellular biology need to be encouraged to allow the optimization of these compounds. Large scale automated tests are pivotal for the efficiency of the screening step, and subsequent evaluation of both the mechanism of action in vitro and pharmacokinetics in vivo are essential for the development of a novel, specific and safe derivative, minimizing adverse effects.

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Targeting PPARalpha in Alzheimer's Disease

Current Alzheimer Research ◽

10.2174/1567205014666170505094549 ◽

2018 ◽

Vol 15 (4) ◽

pp. 345-354 ◽

Cited By ~ 13

Author(s):

Barbara D'Orio ◽

Anna Fracassi ◽

Maria Paola Cerù ◽

Sandra Moreno

Keyword(s):

Oxidative Stress ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Molecular Mechanisms ◽

Redox Homeostasis ◽

Antioxidant Response ◽

Peroxisome Proliferator ◽

Prevailing Paradigm

Background: The molecular mechanisms underlying Alzheimer's disease (AD) are yet to be fully elucidated. The so-called “amyloid cascade hypothesis” has long been the prevailing paradigm for causation of disease, and is today being revisited in relation to other pathogenic pathways, such as oxidative stress, neuroinflammation and energy dysmetabolism. The peroxisome proliferator-activated receptors (PPARs) are expressed in the central nervous system (CNS) and regulate many physiological processes, such as energy metabolism, neurotransmission, redox homeostasis, autophagy and cell cycle. Among the three isotypes (α, β/δ, γ), PPARγ role is the most extensively studied, while information on α and β/δ are still scanty. However, recent in vitro and in vivo evidence point to PPARα as a promising therapeutic target in AD. Conclusion: This review provides an update on this topic, focussing on the effects of natural or synthetic agonists in modulating pathogenetic mechanisms at AD onset and during its progression. Ligandactivated PPARα inihibits amyloidogenic pathway, Tau hyperphosphorylation and neuroinflammation. Concomitantly, the receptor elicits an enzymatic antioxidant response to oxidative stress, ameliorates glucose and lipid dysmetabolism, and stimulates autophagy.

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