scholarly journals β-Chemokines Enhance Parasite Uptake and Promote Nitric Oxide-Dependent Microbiostatic Activity in Murine Inflammatory Macrophages Infected with Trypanosoma cruzi

1999 ◽  
Vol 67 (9) ◽  
pp. 4819-4826 ◽  
Author(s):  
Júlio C. S. Aliberti ◽  
Fabiana S. Machado ◽  
Janeusa T. Souto ◽  
Ana P. Campanelli ◽  
Mauro M. Teixeira ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Neutralizing Antibodies ◽  
Specific Inhibitor ◽  
No Production ◽  
Dependent Manner ◽  
Macrophage Infection ◽  
Parasite Replication ◽  
Ifn Γ

ABSTRACT In the present study, we describe the ability of Trypanosoma cruzi trypomastigotes to stimulate the synthesis of β-chemokines by macrophages. In vivo infection with T. cruzi led to MIP-1α, RANTES, and JE/MCP1 mRNA expression by cells from peritoneal inflammatory exudate. In addition, in vitro infection with T. cruzi resulted in expression of β-chemokine MIP-1α, MIP-1β, RANTES, and JE mRNA by macrophages. The expression of the β-chemokine MIP-1α, MIP-1β, RANTES, and JE proteins by murine macrophages cultured with trypomastigote forms ofT. cruzi was confirmed by immunocytochemistry. Interestingly, macrophage infection with T. cruzi also resulted in NO production, which we found to be mediated mainly by β-chemokines. Hence, treatment with anti-β-chemokine-specific neutralizing antibodies partially inhibited NO release by macrophages incubated with T. cruzi parasites. Further, the addition of the exogenous β-chemokines MIP-1α, MIP-1β, RANTES, and JE/MCP-1 induced an increased T. cruzi uptake, leading to enhanced NO production and control of parasite replication in a dose-dependent manner. l-NMMA, a specific inhibitor of thel-arginine–NO pathway, caused a decrease in NO production and parasite killing when added to cultures of macrophages stimulated with β-chemokines. Among the β-chemokines tested, JE was more potent in inhibiting parasite growth, although it was much less efficient than gamma interferon (IFN-γ). Nevertheless, JE potentiates parasite killing by macrophages incubated with low doses of IFN-γ. Together, these results suggest that in addition to their chemotactic activity, murine β-chemokines may also contribute to enhancing parasite uptake and promoting control of parasite replication in macrophages and may play a role in resistance to T. cruziinfection.

scholarly journals Leukotriene B4 Induces Nitric Oxide Synthesis in Trypanosoma cruzi-Infected Murine Macrophages and Mediates Resistance to Infection

2002 ◽  
Vol 70 (8) ◽  
pp. 4247-4253 ◽  
Author(s):  
A. Talvani ◽  
F. S. Machado ◽  
G. C. Santana ◽  
A. Klein ◽  
L. Barcelos ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Trypanosoma Cruzi ◽  
Leukotriene B4 ◽  
No Production ◽  
Dependent Manner ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Ifn Γ

ABSTRACT The production of nitric oxide (NO) by gamma interferon (IFN-γ)-activated macrophages is a major effector mechanism during experimental Trypanosoma cruzi infection. In addition to IFN-γ, chemoattractant molecules, such as platelet-activating factor (PAF) and CC chemokines, may also activate macrophages to induce NO and mediate the killing of T. cruzi in an NO-dependent manner. Here we investigated the ability of leukotriene B4 (LTB4) to induce the production of NO by macrophages infected with T. cruzi in vitro and whether NO mediated LTB4-induced parasite killing. The activation of T. cruzi-infected but not naive murine peritoneal macrophages with LTB4 induced the time- and concentration-dependent production of NO. In addition, low concentrations of LTB4 acted in synergy with IFN-γ to induce NO production. The NO produced mediated LTB4-induced microbicidal activity in macrophages, as demonstrated by the inhibitory effects of an inducible NO synthase inhibitor. LTB4-induced NO production and parasite killing were LTB4 receptor dependent and were partially blocked by a PAF receptor antagonist. LTB4 also induced significant tumor necrosis factor alpha (TNF-α) production, and blockade of TNF-α suppressed LTB4-induced NO release and parasite killing. A blockade of LTB4 or PAF receptors partially inhibited IFN-γ-induced NO and TNF-α production but not parasite killing. Finally, daily treatment of infected mice with CP-105,696 was accompanied by a significantly higher level of blood parasitemia, but not lethality, than that seen in vehicle-treated animals. In conclusion, our results suggest a role for LTB4 during experimental T. cruzi infection. Chemoattractant molecules such as LTB4 not only may play a major role in leukocyte migration into sites of inflammation in vivo but also, in the event of an infection, may play a relevant role in the activation of recruited leukocytes to kill the invading microorganism in an NO-dependent manner.

scholarly journals Effect ofTityus serrulatusvenom on cytokine production and the activity of murine macrophages

2002 ◽  
Vol 11 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Vera L. Petricevich
Keyword(s):  
Cytokine Production ◽  
Peritoneal Macrophages ◽  
Interferon Γ ◽  
Enzyme Linked Immunosorbent Assay ◽  
No Production ◽  
Dependent Manner ◽  
Immune Functions ◽  
Macrophage Activity ◽  
Ifn Γ

The purpose of this study was to investigate the effects ofTityus serrulatusvenom (TSV) on murine peritoneal macrophages evaluated in terms of activation. The effects of crude TSV were analysed by detection of cytokines, oxygen intermediate metabolites (H2O2) and nitric oxide (NO) in supernatants of peritoneal macrophages. Several functional bioassays were employed including anin vitromodel for envenomating: cytotoxicity of TSV was assessed using the lyses percentage. Tumor necrosis factor (TNF) activity was assayed by measuring its cytotoxic activity on L-929 cells, and interleukin-6 (IL-6) and interferon-γ (IFN-γ) were assayed by enzyme-linked immunosorbent assay, whereas NO levels were detected by Griess colorimetric reactions in culture supernatant of macrophages incubated with TSV and subsequently exposed to either lipopolysaccharide or IFN-γ. Incubation of macrophages with TSV increased production of IL-6 and IFN-γ in a dose-dependent manner. TNF production was not detected in supernatants treated with TSV at any concentration. The increase in IL-6 secretion was not associated with concentration-dependent cytoxicity of TSV on these cells. These data suggest that the cytotoxicity does not appear to be the main cause of an increased cytokine production by these cells. Although NO is an important effector molecule in macrophage microbicidal activity, the inducing potential of the test compounds for its release was found to be very moderate, ranging from 125 to 800 mM. Interestingly, NO levels of peritoneal macrophages were increased after IFN-γ. Moreover, NO production had an apparent effect on macrophage activity. The results obtained here also shown that the TSV induces an important elevation in H2O2release. These results combined with NO production suggest that TSV possesses significant immunomodulatory activities capable of stimulating immune functionsin vitro.

scholarly journals Murine monoclonal antibodies against RBD of SARS-CoV-2 neutralize authentic wild type SARS-CoV-2 as well as B.1.1.7 and B.1.351 viruses and protect in vivo in a mouse model in a neutralization dependent manner

2021 ◽  
Author(s):  
Fatima Amanat ◽  
Shirin Strohmeier ◽  
Wen-Hsin Lee ◽  
Sandhya Bangaru ◽  
Andrew B Ward ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Mouse Model ◽  
Neutralizing Antibodies ◽  
Dependent Manner ◽  
Receptor Binding Domain ◽  
Wild Type ◽  
Murine Monoclonal Antibodies

After first emerging in December 2019 in China, severe acute respiratory syndrome 2 (SARS-CoV-2) has since caused a pandemic leading to millions of infections and deaths worldwide. Vaccines have been developed and authorized but supply of these vaccines is currently limited. With new variants of the virus now emerging and spreading globally, it is essential to develop therapeutics that are broadly protective and bind conserved epitopes in the receptor binding domain (RBD) or the whole spike of SARS-CoV-2. In this study, we have generated mouse monoclonal antibodies (mAbs) against different epitopes on the RBD and assessed binding and neutralization against authentic SARS-CoV-2. We have demonstrated that antibodies with neutralizing activity, but not non-neutralizing antibodies, lower viral titers in the lungs when administered in a prophylactic setting in vivo in a mouse challenge model. In addition, most of the mAbs cross-neutralize the B.1.351 as well as the B.1.1.7 variants in vitro.

scholarly journals Motility patterns of Trypanosoma cruzi trypomastigotes correlate with the efficiency of parasite invasion in vitro

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jorge A. Arias-del-Angel ◽  
Jesús Santana-Solano ◽  
Moisés Santillán ◽  
Rebeca G. Manning-Cela
Keyword(s):  
Trypanosoma Cruzi ◽  
Cell Line ◽  
Mammalian Cells ◽  
Dependent Manner ◽  
Parasite Invasion ◽  
Mammalian Cell Cultures ◽  
A Cell ◽  
Parasite Replication ◽  
Parasite Motility

Abstract Numerous works have demonstrated that trypanosomatid motility is relevant for parasite replication and sensitivity. Nonetheless, although some findings indirectly suggest that motility also plays an important role during infection, this has not been extensively investigated. This work is aimed at partially filling this void for the case of Trypanosoma cruzi. After recording swimming T. cruzi trypomastigotes (CL Brener strain) and recovering their individual trajectories, we statistically analyzed parasite motility patterns. We did this with parasites that swim alone or above monolayer cultures of different cell lines. Our results indicate that T. cruzi trypomastigotes change their motility patterns when they are in the presence of mammalian cells, in a cell-line dependent manner. We further performed infection experiments in which each of the mammalian cell cultures were incubated for 2 h together with trypomastigotes, and measured the corresponding invasion efficiency. Not only this parameter varied from cell line to cell line, but it resulted to be positively correlated with the corresponding intensity of the motility pattern changes. Together, these results suggest that T. cruzi trypomastigotes are capable of sensing the presence of mammalian cells and of changing their motility patterns accordingly, and that this might increase their invasion efficiency.

scholarly journals IFN-γ down-regulates the PD-1 expression and assist nivolumab in PD-1-blockade effect on CD8+ T-lymphocytes in pancreatic cancer

BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Guoping Ding ◽  
Tao Shen ◽  
Chen Yan ◽  
Mingjie Zhang ◽  
Zhengrong Wu ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
T Lymphocytes ◽  
Ductal Adenocarcinoma ◽  
Cytotoxic Activities ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cd8 T Lymphocytes ◽  
Ifn Γ

Abstract Background Pancreatic cancer is characterized by a highly immunosuppressive tumor microenvironment and evasion of immune surveillance. Although programmed cell death 1 receptor (PD-1) blockade has achieved certain success in immunogenic cancers, the responses to the PD-1 antibody are not effective or sustained in patients with pancreatic cancer. Methods Firstly, PD-1 expressions on peripheral CD8+ T-lymphocytes of patients with pancreatic cancer and healthy donors were measured. In in vitro study, peripheral T-lymphocytes were isolated and treated with nivolumab and/or interferon-γ, and next, PD-1-blockade effects, proliferations, cytokine secretions and cytotoxic activities were tested after different treatments. In in vivo study, mice bearing subcutaneous pancreatic cancer cell lines were treated with induced T-lymphocytes and tumor sizes were measured. Results PD-1 protein expression is increased on peripheral CD8+ T cells in patients with pancreatic ductal adenocarcinoma compared with that in health donor. PD-1 expression on CD8+ T-lymphocytes was decreased by nivolumab in a concentration-dependent manner in vitro. IFN-γ could directly down-regulate expression of PD-1 in vitro. Furthermore, the combination therapy of nivolumab and IFN-γ resulted in greatest effect of PD-1-blockde (1.73 ± 0.78), compared with IFN-γ along (18.63 ± 0.82) and nivolumab along (13.65 ± 1.22). Moreover, the effects of nivolumab plus IFN-γ largest promoted the T-lymphocytes function of proliferations, cytokine secretions and cytotoxic activities. Most importantly, T-lymphocytes induced by nivolumab plus IFN-γ presented the best repression of tumor growth. Conclusions IFN-γ plus a PD-1-blockading agent could enhance the immunologic function and might play a crucial role in effective adoptive transfer treatments of pancreatic cancer.

dSLIM Immunomodulators Induce Anti-Tumor Responses Both In Vitro and In Vivo.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1727-1727
Author(s):  
Manuel Schmidt ◽  
Javier de Cristobal ◽  
Astrid Sander ◽  
Bernadette Brzezicha ◽  
Sven A. König Merediz ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Neutralizing Antibodies ◽  
De Novo ◽  
Tumor Cell Line ◽  
Control Group ◽  
Γδt Cells ◽  
Ifn Γ

Abstract Cytosine-guanine (CpG) motifs containing oligonucleotides (ODN) are commonly used for immunomodulatory purpose in cancer therapy and for the treatment of allergic diseases since they resemble bacterial DNA and serve as “danger signals”. These CpG-ODNs promote predominately a TH1-response with secretion of IL-12 and IFN-γ, In addition their broad potential includes activation of B-cell proliferation, monocyte stimulation and secretion of IgM and IL-6, and stimulation of plasmacytoid DC to produce IFN-α/-β and thus γδT-cells and NK-cells to express CD69 and secrete IFN-γ. Usually phosphorothioate (PS) modifications are to enhance the stability, but these are leading to several side-effects, like severe organ enlargements, morphological changes and immunosuppression in mice. We designed immunomodulatory molecules based on short covalently-closed dumbbell-like structures (dSLIM) to stabilize the DNA without the otherwise necessary PS-modification. To evaluate the anti-tumor effect of the dSLIM molecules we developed an in vitro anti-tumor assay. This assay uses supernatant from dSLIM-activated human PBMCs for incubation with tumor cells in vitro. We observed increased apoptosis and necrosis of the HT-29 tumor cell line after incubation with supernatant from dSLIM-treated PBMC which was significantly higher than the effect of supernatant from non-treated PBMC. In addition, supernatant from dSLIM-treated PBMC increased the expression of HLA-ABC on the tumor cells, a pre-requisite for tumor cell recognition by the immune system. These effects were confirmed with human HEK293 and murine Renca cell lines. Analyzing the effect with neutralizing antibodies to various apoptosis-related cytokines, we observed a crucial role of IFN-γ but not IFN-α or TNFα. To investigate the anti-tumor effects of dSLIM in vivo, we employed a SKH1 murine model which is prone to spontaneous development of papillomas. Using chemicals for initiation and weekly promotion of de novo papilloma development we compared groups of weekly s.c. or i.p. dSLIM injections, respectively, with the PBS control group. The number of papilloma developing mice was significantly lower in the dSLIM groups and the total number of papillomas on all mice was reduced by approximately 50%. In conclusion, we showed that dSLIM immunomodulators exhibit potent anti-tumor effects in vitro and in vivo.

scholarly journals Critical role for Epac1 in inflammatory pain controlled by GRK2-mediated phosphorylation of Epac1

2016 ◽  
Vol 113 (11) ◽  
pp. 3036-3041 ◽  
Author(s):  
Pooja Singhmar ◽  
XiaoJiao Huo ◽  
Niels Eijkelkamp ◽  
Susana Rojo Berciano ◽  
Faiza Baameur ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Molecular Mechanism ◽  
Inflammatory Pain ◽  
Critical Role ◽  
Specific Inhibitor ◽  
Mechanical Hyperalgesia ◽  
Dependent Manner ◽  
Phosphorylation Event

cAMP signaling plays a key role in regulating pain sensitivity. Here, we uncover a previously unidentified molecular mechanism in which direct phosphorylation of the exchange protein directly activated by cAMP 1 (EPAC1) by G protein kinase 2 (GRK2) suppresses Epac1-to-Rap1 signaling, thereby inhibiting persistent inflammatory pain. Epac1−/− mice are protected against inflammatory hyperalgesia in the complete Freund’s adjuvant (CFA) model. Moreover, the Epac-specific inhibitor ESI-09 inhibits established CFA-induced mechanical hyperalgesia without affecting normal mechanical sensitivity. At the mechanistic level, CFA increased activity of the Epac target Rap1 in dorsal root ganglia of WT, but not of Epac1−/−, mice. Using sensory neuron-specific overexpression of GRK2 or its kinase-dead mutant in vivo, we demonstrate that GRK2 inhibits CFA-induced hyperalgesia in a kinase activity-dependent manner. In vitro, GRK2 inhibits Epac1-to-Rap1 signaling by phosphorylation of Epac1 at Ser-108 in the Disheveled/Egl-10/pleckstrin domain. This phosphorylation event inhibits agonist-induced translocation of Epac1 to the plasma membrane, thereby reducing Rap1 activation. Finally, we show that GRK2 inhibits Epac1-mediated sensitization of the mechanosensor Piezo2 and that Piezo2 contributes to inflammatory mechanical hyperalgesia. Collectively, these findings identify a key role of Epac1 in chronic inflammatory pain and a molecular mechanism for controlling Epac1 activity and chronic pain through phosphorylation of Epac1 at Ser-108. Importantly, using the Epac inhibitor ESI-09, we validate Epac1 as a potential therapeutic target for chronic pain.

scholarly journals Streptococcus gallolyticus Increases Expression and Activity of Aryl Hydrocarbon Receptor-Dependent CYP1 Biotransformation Capacity in Colorectal Epithelial Cells

2021 ◽  
Vol 11 ◽  
Author(s):  
Rahwa Taddese ◽  
Rian Roelofs ◽  
Derk Draper ◽  
Xinqun Wu ◽  
Shaoguang Wu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Aryl Hydrocarbon Receptor ◽  
Specific Inhibitor ◽  
Intestinal Bacteria ◽  
Opportunistic Pathogen ◽  
Dependent Manner ◽  
Aryl Hydrocarbon ◽  
Streptococcus Gallolyticus

ObjectiveThe opportunistic pathogen Streptococcus gallolyticus is one of the few intestinal bacteria that has been consistently linked to colorectal cancer (CRC). This study aimed to identify novel S. gallolyticus-induced pathways in colon epithelial cells that could further explain how S. gallolyticus contributes to CRC development.Design and ResultsTranscription profiling of in vitro cultured CRC cells that were exposed to S. gallolyticus revealed the specific induction of oxidoreductase pathways. Most prominently, CYP1A and ALDH1 genes that encode phase I biotransformation enzymes were responsible for the detoxification or bio-activation of toxic compounds. A common feature is that these enzymes are induced through the Aryl hydrocarbon receptor (AhR). Using the specific inhibitor CH223191, we showed that the induction of CYP1A was dependent on the AhR both in vitro using multiple CRC cell lines as in vivo using wild-type C57bl6 mice colonized with S. gallolyticus. Furthermore, we showed that CYP1 could also be induced by other intestinal bacteria and that a yet unidentified diffusible factor from the S. galloltyicus secretome (SGS) induces CYP1A enzyme activity in an AhR-dependent manner. Importantly, priming CRC cells with SGS increased the DNA damaging effect of the polycyclic aromatic hydrocarbon 3-methylcholanthrene.ConclusionThis study shows that gut bacteria have the potential to modulate the expression of biotransformation pathways in colonic epithelial cells in an AhR-dependent manner. This offers a novel theory on the contribution of intestinal bacteria to the etiology of CRC by modifying the capacity of intestinal epithelial or (pre-)cancerous cells to (de)toxify dietary components, which could alter intestinal susceptibility to DNA damaging events.

scholarly journals Involvement of the vacuolar proton-translocating ATPase in multiple steps of the endo-lysosomal system and in the contractile vacuole system of Dictyostelium discoideum

1996 ◽  
Vol 109 (6) ◽  
pp. 1479-1495 ◽  
Author(s):  
L.A. Temesvari ◽  
J.M. Rodriguez-Paris ◽  
J.M. Bush ◽  
L. Zhang ◽  
J.A. Cardelli
Keyword(s):  
Morphological Changes ◽  
Specific Inhibitor ◽  
Fluid Phase ◽  
Contractile Vacuole ◽  
Dependent Manner ◽  
Concanamycin A ◽  
Latex Beads ◽  
And Function

We have investigated the effects of Concanamycin A (CMA), a specific inhibitor of vacuolar type H(+)-ATPases, on acidification and function of the endo-lysosomal and contractile vacuole (CV) systems of D. discoideum. This drug inhibited acidification and increased the pH of endo-lysosomal vesicles both in vivo and in vitro in a dose dependent manner. Treatment also inhibited endocytosis and exocytosis of fluid phase, and phagocytosis of latex beads. This report also confirms our previous conclusions (Cardelli et al. (1989) J. Biol. Chem. 264, 3454–3463) that maintenance of acidic pH in lumenal compartments is required for efficient processing and targeting of a lysosomal enzyme, alpha-mannosidase. CMA treatment compromised the function of the contractile vacuole complex as amoebae exposed to a hypo-osmotic environment in the presence of CMA, swelled rapidly and ruptured. Fluorescence microscopy revealed that CMA treatment induced gross morphological changes in D. discoideum cells, characterized by the formation of large intracellular vacuoles containing fluid phase. The reticular membranes of the CV system were also no longer as apparent in drug treated cells. Finally, this is the first report describing cells that can adapt in the presence of CMA; in nutrient medium, D. discoideum overcame the effects of CMA after one hour of drug treatment even in the absence of protein synthesis. Upon adaptation to CMA, normal sized endo-lysosomal vesicles reappeared, endo-lysosomal pH decreased, and the rate of endocytosis, exocytosis and phagocytosis returned to normal. This study demonstrates that the V-H(+)-ATPase plays an important role in maintaining the integrity and function of the endo-lysosomal and CV systems and that D. discoideum can compensate for the loss of a functional V-H(+)-ATPase.

Melatonin decreases circulating Trypanosoma cruzi load with no effect on tissue parasite replication.

2020 ◽  
Author(s):  
MAIARA VOLTARELLI PROVIDELLO ◽  
Gisele Bulhões Portapilla ◽  
Pedro Alexandre Sampaio Oliveira ◽  
Carla Brigagão Pacheco da Silva ◽  
Naira Ferreira Anchieta ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Cardiac Tissue ◽  
Direct Action ◽  
Protective Action ◽  
Cardiac Damage ◽  
Redox Imbalance ◽  
Parasitic Load ◽  
Parasite Replication

Cardiac damage during the acute phase of Chagas disease (CD) is associated with an increase in pro-inflammatory markers and oxidative stress. Melatonin has emerged as a promising therapy for CD due to its antioxidant and immunomodulatory properties. However, the protective action of melatonin in the cardiac tissue as well as its direct action on the parasite cycle is not fully understood. We investigated the effects of melatonin on heart parasitism in mice infected with Trypanosoma cruzi (T. cruzi) and also its effects on the parasitic proliferation in vitro. Our in vivo study showed that melatonin reduced circulating parasitemia load, but did not control tissue (heart, liver and spleen) parasitism in mice. Melatonin did not prevent the redox imbalance in the left ventricle of infected mice. Our in vitro findings showed that melatonin did not inhibit parasites replication within cells, but rather increased their release from cells. Melatonin did not control parasitism load in the heart or prevented the cardiac redox imbalance induced by acute T. cruzi infection. The hormone controlled the circulating parasitic load, but in cells melatonin accelerated parasitic release, a response that can be harmful.

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