Quantifying Human Monocyte Chemotaxis In Vitro and Murine Lymphocyte Trafficking In Vivo

Oxidized low density lipoproteins (LDL) are highly suspected of initiating the atherosclerosis process. Thyroid hormones and structural analogues have been reported to protect LDL from lipid peroxidation induced by Cu2+ or the free radical generator 2,2'-azobis-'2-amidinopropane' dihydrochloride in vitro. We have examined the effects of thyroid compounds on macrophage-induced LDL oxidation. Human monocyte-derived macrophages (differentiated U937 cells) were incubated for 24 h with LDL and different concentrations (0-20 microM) of 3,5,3'-triiodo-l -thyronine (T3), 3,5,3',5'-tetraiodo-L-thyronine (T4), 3,3',5'-tri-iodo-l -thyronine (rT3), the T3 acetic derivative (3,5,3'-tri-iodothyroacetic acid; TA3) or L-thyronine (T0) (experiment 1). Cells were also preincubated for 24 h with 1 or 10 microM of the compounds, washed twice, then incubated again for 24 h with LDL (experiment 2). Oxidation was evaluated by measurement of thiobarbituric acid-reactive substances (TBARS) and cell viability by lactate deshydrogenase release. In experiment 1, T0 had no effect, whereas the other compounds decreased LDL TBARS production, but T3 and TA3 were less active than T4 and rT3 (IC50: 11.0 +/- 2.6 and 8.1 +/- 0.8 vs 1.4 +/- 0.5 and 0.9 +/- 0.3 microM respectively). In experiment 2, the compounds at 1 microM had no effect; at 10 microM, T3 and rT3 slightly reduced LDL TBARS production, whereas TA3 and T4 inhibited it by about 50% and 70% respectively. TBARS released by the cells were also highly decreased by T3, T4, rT3 and TA3 in experiment 1, but only by T3 (30%) and T4 (70%) in experiment 2. Cell viability was not affected by the compounds except slightly by TA3 at 10 microM. The data suggested that the physico-chemical antioxidant capacity of thyroid compounds was modulated by their action on the intracellular redox systems of macrophage. Overall cellular effects of T3 led to a reduction of its antioxidant capacity whereas those of T4 increased it. Thus T4 might protect LDL against cellular oxidation in vivo more than T3.

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Omega-1, a glycoprotein secreted by Schistosoma mansoni eggs, drives Th2 responses

Journal of Experimental Medicine ◽

10.1084/jem.20082460 ◽

2009 ◽

Vol 206 (8) ◽

pp. 1673-1680 ◽

Cited By ~ 237

Author(s):

Bart Everts ◽

Georgia Perona-Wright ◽

Hermelijn H. Smits ◽

Cornelis H. Hokke ◽

Alwin J. van der Ham ◽

...

Keyword(s):

Schistosoma Mansoni ◽

Human Monocyte ◽

Potent Inducer ◽

T Helper 2 ◽

Mediated Effects ◽

Reporter Mice ◽

Th2 Polarization ◽

Th2 Responses

Soluble egg antigens of the parasitic helminth Schistosoma mansoni (S. mansoni egg antigen [SEA]) induce strong Th2 responses both in vitro and in vivo. However, the specific molecules that prime the development of Th2 responses have not been identified. We report that omega-1, a glycoprotein which is secreted from S. mansoni eggs and present in SEA, is capable of conditioning human monocyte-derived dendritic cells in vitro to drive T helper 2 (Th2) polarization with similar characteristics as whole SEA. Furthermore, using IL-4 dual reporter mice, we show that both natural and recombinant omega-1 alone are sufficient to generate Th2 responses in vivo, even in the absence of IL-4R signaling. Finally, omega-1–depleted SEA displays an impaired capacity for Th2 priming in vitro, but not in vivo, suggesting the existence of additional factors within SEA that can compensate for the omega-1–mediated effects. Collectively, we identify omega-1, a single component of SEA, as a potent inducer of Th2 responses.

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Thioholgamide A, a New Anti-Proliferative Anti-Tumor Agent, Modulates Macrophage Polarization and Metabolism

Cancers ◽

10.3390/cancers12051288 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1288 ◽

Cited By ~ 2

Author(s):

Charlotte Dahlem ◽

Wei Xiong Siow ◽

Maria Lopatniuk ◽

William K. F. Tse ◽

Sonja M. Kessler ◽

...

Keyword(s):

Tumor Microenvironment ◽

Tumor Cells ◽

Cell Metabolism ◽

Macrophage Polarization ◽

Human Monocyte ◽

Live Cell ◽

Hallmarks Of Cancer ◽

Culture Models

Natural products represent powerful tools searching for novel anticancer drugs. Thioholgamide A (thioA) is a ribosomally synthesized and post-translationally modified peptide, which has been identified as a product of Streptomyces sp. MUSC 136T. In this study, we provide a comprehensive biological profile of thioA, elucidating its effects on different hallmarks of cancer in tumor cells as well as in macrophages as crucial players of the tumor microenvironment. In 2D and 3D in vitro cell culture models thioA showed potent anti-proliferative activities in cancer cells at nanomolar concentrations. Anti-proliferative actions were confirmed in vivo in zebrafish embryos. Cytotoxicity was only induced at several-fold higher concentrations, as assessed by live-cell microscopy and biochemical analyses. ThioA exhibited a potent modulation of cell metabolism by inhibiting oxidative phosphorylation, as determined in a live-cell metabolic assay platform. The metabolic modulation caused a repolarization of in vitro differentiated and polarized tumor-promoting human monocyte-derived macrophages: ThioA-treated macrophages showed an altered morphology and a modulated expression of genes and surface markers. Taken together, the metabolic regulator thioA revealed low activities in non-tumorigenic cells and an interesting anti-cancer profile by orchestrating different hallmarks of cancer, both in tumor cells as well as in macrophages as part of the tumor microenvironment.

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Anti-apolipoprotein A-1 auto-antibodies as active modulators of atherothrombosis

Thrombosis and Haemostasis ◽

10.1160/th16-03-0229 ◽

2016 ◽

Vol 116 (09) ◽

pp. 554-564 ◽

Cited By ~ 15

Author(s):

Federico Carbone ◽

Fabienne Burger ◽

Aline Roth ◽

Maria Bertolotto ◽

Bianca Pane ◽

...

Keyword(s):

Human Serum ◽

Elective Surgery ◽

Human Monocyte ◽

Serum Levels ◽

Passive Immunisation ◽

Apolipoprotein A ◽

Nf Kappab ◽

Expression And Activity

SummaryHumoral autoimmune-mediated inflammation plays a role in atherogenesis, and potentially in arterial thrombosis. Anti-apolipoprotein A-1 (apoA-1) IgG have been reported to represent emergent mediators of atherogenesis through Toll-like receptors (TLR) 2, 4 and CD14 signalling. We investigated the role of anti-apoA-1 IgG on tissue factor (TF) expression and activation, a key coagulation regulator underlying atherothrombosis. Atherothrombosis features were determined by immunohistochemical TF staining of human carotid biopsies derived from patients with severe carotid stenosis undergoing elective surgery (n=176), and on aortic roots of different genetic backgrounds mice (ApoE-/-; TLR2-/-ApoE-/- and TLR4-/-ApoE-/-) exposed to passive immunisation with anti-apoA-1 IgG. Human serum levels of anti-apoA-1 IgG were measured by ELISA. In vitro, on human-monocyte-derived-macrophages (HMDM) the anti-apoA-1 IgG increased TF expression and activity were analysed by FACS and chromogenic assays in presence of different pharmacological inhibitors. Human serum anti-apoA-1 IgG levels significantly correlated to intraplaque TF expression in carotid biopsies (r=0.31, p<0.001), which was predictive of clinically symptomatic lesions. On HMDM, anti-apoA-1 IgG induced a TLR2, 4 and CD14-dependent increase in TF expression and activity, involving NF-kappaB and a c-Jun N-terminal kinase-dependent AP-1 transcription factors. In ApoE-/- mice, anti-apoA-1 IgG passive immunisation significantly enhanced intraplaque TF expression when compared to control IgG. This effect was lost in both TLR2-/-ApoE-/- and TLR4-/-ApoE-/- mice. These results demonstrate that anti-apoA-1 IgG are associated with TF expression in human atherosclerotic plaques, induce TF expression in vitro and in vivo through TLR2 and 4 signalling, supporting a possible causal relationship between anti-apoA-1 IgG and atherothrombosis.

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In vitro and in vivo immunomodulatory properties of octyl-β-d-galactofuranoside during Leishmania donovani infection

Parasites & Vectors ◽

10.1186/s13071-019-3858-0 ◽

2019 ◽

Vol 12 (1) ◽

Author(s):

Hélène Guegan ◽

Kevin Ory ◽

Sorya Belaz ◽

Aurélien Jan ◽

Sarah Dion ◽

...

Keyword(s):

Immune Response ◽

Leishmania Donovani ◽

Parasite Burden ◽

Human Monocyte ◽

Fold Increase ◽

Control Group ◽

End Of Treatment ◽

Immunosuppressed Patients

Abstract Background The chemotherapeutic arsenal available to treat visceral leishmaniasis is currently limited, in view of many drawbacks such as high cost, toxicity or emerging resistance. New therapeutic strategies are particularly needed to improve the management and the outcome in immunosuppressed patients. The combination of an immunomodulatory drug to a conventional anti-Leishmania treatment is an emerging concept to reverse the immune bias from Th2 to Th1 response to boost healing and prevent relapses. Methods Here, immunostimulating and leishmanicidal properties of octyl-β-d-galactofuranose (Galf) were assessed in human monocyte-derived macrophages (HM) and in a murine model, after challenge with Leishmania donovani promastigotes. We recorded parasite loads and expression of various cytokines and immune effectors in HM and mouse organs (liver, spleen, bone marrow), following treatment with free (Galf) and liposomal (L-Galf) formulations. Results Both treatments significantly reduced parasite proliferation in HM, as well as liver parasite burden in vivo (Galf, P < 0.05). Consistent with in vitro results, we showed that Galf- and L-Galf-treated mice displayed an enhanced Th1 immune response, particularly in the spleen where pro-inflammatory cytokines TNF-α, IL-1β and IL-12 were significantly overexpressed compared to control group. The hepatic recruitment of myeloid cells was also favored by L-Galf treatment as evidenced by the five-fold increase of myeloperoxidase (MPO) induction, which was associated with a higher number of MPO-positive cells within granulomas. By contrast, the systemic level of various cytokines such as IL-1β, IL-6, IL-17A or IL-27 was drastically reduced at the end of treatment. Conclusions Overall, these results suggest that Galf could be tested as an adjuvant in combination with current anti-parasitic drugs, to restore an efficient immune response against infection in a model of immunosuppressed mice.

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Pasteurella multocida Toxin Activates Human Monocyte-Derived and Murine Bone Marrow-Derived Dendritic Cells In Vitro but Suppresses Antibody Production In Vivo

Infection and Immunity ◽

10.1128/iai.73.1.413-421.2005 ◽

2005 ◽

Vol 73 (1) ◽

pp. 413-421 ◽

Cited By ~ 22

Author(s):

Kenneth C. Bagley ◽

Sayed F. Abdelwahab ◽

Robert G. Tuskan ◽

George K. Lewis

Keyword(s):

Bone Marrow ◽

Dendritic Cells ◽

Phospholipase C ◽

Cholera Toxin ◽

Pasteurella Multocida ◽

Human Monocyte ◽

Mouse Bone Marrow ◽

Dependent Manner

ABSTRACT Pasteurella multocida toxin (PMT) is a potent mitogen for fibroblasts and osteoblastic cells. PMT activates phospholipase C-β through Gqα, and the activation of this pathway is responsible for its mitogenic activity. Here, we investigated the effects of PMT on human monocyte-derived dendritic cells (MDDC) in vitro and show a novel activity for PMT. In this regard, PMT activates MDDC to mature in a dose-dependent manner through the activation of phospholipase C and subsequent mobilization of calcium. This activation was accompanied by enhanced stimulation of naïve alloreactive T cells and dominant inhibition of interleukin-12 production in the presence of saturating concentrations of lipopolysaccharide. Surprisingly, although PMT mimics the activating effects of cholera toxin on human MDDC and mouse bone marrow-derived dendritic cells, we found that PMT is not a mucosal adjuvant and that it suppresses the adjuvant effects of cholera toxin in mice. Together, these results indicate discordant effects for PMT in vitro compared to those in vivo.

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Preclinical In Vitro and In Vivo Characterization of the Fully Human Monoclonal IgM Antibody KBPA101 Specific for Pseudomonas aeruginosa Serotype IATS-O11

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01142-09 ◽

2010 ◽

Vol 54 (6) ◽

pp. 2338-2344 ◽

Cited By ~ 35

Author(s):

Michael P. Horn ◽

Adrian W. Zuercher ◽

Martin A. Imboden ◽

Michael P. Rudolf ◽

Hedvika Lazar ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Treatment Options ◽

Human Monoclonal Antibody ◽

Human Monocyte ◽

Peripheral Blood Lymphocytes ◽

Infection Model ◽

High Avidity ◽

Burn Wound

ABSTRACT Pseudomonas aeruginosa infection in ventilator-associated pneumonia is a serious and often life-threatening complication in intensive care unit patients, and new treatment options are needed. We used B-cell-enriched peripheral blood lymphocytes from a volunteer immunized with a P. aeruginosa O-polysaccharide-toxin A conjugate vaccine to generate human hybridoma cell lines producing monoclonal antibodies specific for individual P. aeruginosa lipopolysaccharide serotypes. The fully human monoclonal antibody secreted by one of these lines, KBPA101, is an IgM/κ antibody that binds P. aeruginosa of International Antigenic Typing System (IATS) serotype O11 with high avidity (5.81 × 107 M−1 ± 2.8 × 107 M−1) without cross-reacting with other serotypes. KBPA101 specifically opsonized the P. aeruginosa of IATS O11 serotype and mediated complement-dependent phagocytosis in vitro by the human monocyte-like cell line HL-60 at a very low concentration (half-maximal phagocytosis at 0.16 ng/ml). In vivo evaluation of KBPA101 demonstrated a dose-response relationship for protection against systemic infections in a murine burn wound sepsis model, where 70 to 100% of animals were protected against lethal challenges with P. aeruginosa at doses as low as 5 μg/animal. Furthermore, a high efficacy of KBPA101 in protection from local respiratory infections in an acute lung infection model in mice was demonstrated. Preclinical toxicology evaluation on human tissue, in rabbits, and in mice did not indicate any toxicity of KBPA101. Based on these preclinical findings, the first human clinical trials have been initiated.

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Immunoglobulin A Antibodies against Ricin A and B Subunits Protect Epithelial Cells from Ricin Intoxication

Infection and Immunity ◽

10.1128/iai.02088-05 ◽

2006 ◽

Vol 74 (6) ◽

pp. 3455-3462 ◽

Cited By ~ 46

Author(s):

Nicholas J. Mantis ◽

Carolyn R. McGuinness ◽

Oluwakemi Sonuyi ◽

Gary Edwards ◽

Stephanie A. Farrant

Keyword(s):

Epithelial Cells ◽

Immunoglobulin A ◽

Human Monocyte ◽

Intestinal Epithelial ◽

Mesenteric Lymph Nodes ◽

Cell Monolayers ◽

Iga Antibodies ◽

Ricin A

ABSTRACT Epithelial cells of the respiratory and gastrointestinal tracts are extremely vulnerable to the cytotoxic effects of ricin, a Shiga-like toxin with ribosome-inactivating properties. While mucosal immunity to ricin correlates with secretory immunoglobulin A (IgA) antibody levels in vivo, the potential of IgA to protect epithelial cells from ricin in vitro has not been examined due to the unavailability of well-defined antitoxin IgA antibodies. Here we report the characterization of four monoclonal IgA antibodies (IgA MAbs) produced from the Peyer's patches and mesenteric lymph nodes of BALB/c mice immunized intragastrically with ricin toxoid. Two IgA MAbs (33G2 and 35H6) were active against ricin's lectin subunit (RTB), and two (23D7 and 25A4) reacted with the toxin's enzymatic subunit (RTA). All four IgA MAbs neutralized ricin in a Vero cell cytotoxicity assay, blocked toxin-induced interleukin-8 release by the human monocyte/macrophage cell line 28SC, and protected polarized epithelial cell monolayers from ricin-mediated protein synthesis inhibition. 33G2 and 35H6 reduced ricin binding to the luminal surfaces of human intestinal epithelial cells to undetectable levels in tissue section overlay assays, whereas 23D7 had no effect on toxin attachment. 23D7 and 25A4 did, however, reduce ricin transcytosis across MDCK II cell monolayers, possibly by interfering with intracellular toxin transport. We conclude that IgA antibodies against RTA and RTB can protect mucosal epithelial cells from ricin intoxication.

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Human Monocyte Recognition of Adenosine-Based Cyclic Dinucleotides Unveils the A2a GαsProtein-Coupled Receptor Tonic Inhibition of Mitochondrially Induced Cell Death

Molecular and Cellular Biology ◽

10.1128/mcb.01204-14 ◽

2014 ◽

Vol 35 (2) ◽

pp. 479-495 ◽

Cited By ~ 10

Author(s):

Marie Tosolini ◽

Frédéric Pont ◽

Delphine Bétous ◽

Emmanuel Ravet ◽

Laetitia Ligat ◽

...

Keyword(s):

Cell Death ◽

Mammalian Cells ◽

Mitochondrial Permeability Transition ◽

Human Monocyte ◽

Inverse Agonist ◽

Apoptotic Pathway ◽

Cyclic Dinucleotides ◽

Agonist Ligands

Cyclic dinucleotides are important messengers for bacteria and protozoa and are well-characterized immunity alarmins for infected mammalian cells through intracellular binding to STING receptors. We sought to investigate their unknown extracellular effects by adding cyclic dinucleotides to the culture medium of freshly isolated human blood cellsin vitro. Here we report that adenosine-containing cyclic dinucleotides induce the selective apoptosis of monocytes through a novel apoptotic pathway. We demonstrate that these compounds are inverse agonist ligands of A2a, a Gαs-coupled adenosine receptor selectively expressed by monocytes. Inhibition of monocyte A2a by these ligands induces apoptosis through a mechanism independent of that of the STING receptors. The blockade of basal (adenosine-free) signaling from A2a inhibits protein kinase A (PKA) activity, thereby recruiting cytosolic p53, which opens the mitochondrial permeability transition pore and impairs mitochondrial respiration, resulting in apoptosis. A2a antagonists and inverse agonist ligands induce apoptosis of human monocytes, while A2a agonists are antiapoptotic.In vivo, we used a mock developing human hematopoietic system through NSG mice transplanted with human CD34+cells. Treatment with cyclic di-AMP selectively depleted A2a-expressing monocytes and their precursors via apoptosis. Thus, monocyte recognition of cyclic dinucleotides unravels a novel proapoptotic pathway: the A2a Gαsprotein-coupled receptor (GPCR)-driven tonic inhibitory signaling of mitochondrion-induced cell death.

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Ezh2 as an epigenetic checkpoint regulator during monocyte differentiation: a potential target to improve cardiac repair after myocardial infarction

10.21203/rs.3.rs-263770/v1 ◽

2021 ◽

Author(s):

Julie Rondeaux ◽

Deborah Groussard ◽

Sylvanie Renet ◽

Virginie Tardif ◽

Anaïs Dumesnil ◽

...

Keyword(s):

Myocardial Infarction ◽

Macrophage Polarization ◽

Human Monocyte ◽

Cardiac Repair ◽

Monocyte Differentiation ◽

Cardiac Inflammation ◽

H3k27 Methylation ◽

Epigenetic Modulation

Abstract Epigenetic regulation of histone H3K27 methylation has recently emerged as a key step during alternative M2-like macrophage polarization, essential for cardiac repair after Myocardial Infarction (MI). We hypothesized that EZH2, responsible for H3K27 methylation, could act as an epigenetic checkpoint regulator during this process. We demonstrate for the first-time an EZH2 ectopic, and putative inactive, cytoplasmic localization of the epigenetic enzyme, during monocyte differentiation in vitro as well as in M2 macrophages in vivo during post-MI cardiac inflammation. Moreover, we show that pharmacological EZH2 inhibition, with GSK-343, resolves H3K27 methylation at the promoter of bivalent genes, thus enhancing their expression to promote human monocyte repair functions. In line with this protective effect, GSK-343 treatment accelerated cardiac inflammatory resolution preventing infarct expansion and subsequent cardiac dysfunction after MI in vivo. In conclusion, our study reveals that epigenetic modulation of cardiac-infiltrating immune cells may hold promise to limit adverse cardiac remodeling after MI.

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