Cyclic AMP Regulates Key Features of Macrophages via PKA: Recruitment, Reprogramming and Efferocytosis

Macrophages are central to inflammation resolution, an active process aimed at restoring tissue homeostasis following an inflammatory response. Here, the effects of db-cAMP on macrophage phenotype and function were investigated. Injection of db-cAMP into the pleural cavity of mice induced monocytes recruitment in a manner dependent on PKA and CCR2/CCL2 pathways. Furthermore, db-cAMP promoted reprogramming of bone-marrow-derived macrophages to a M2 phenotype as seen by increased Arg-1/CD206/Ym-1 expression and IL-10 levels (M2 markers). Db-cAMP also showed a synergistic effect with IL-4 in inducing STAT-3 phosphorylation and Arg-1 expression. Importantly, db-cAMP prevented IFN-γ/LPS-induced macrophage polarization to M1-like as shown by increased Arg-1 associated to lower levels of M1 cytokines (TNF-α/IL-6) and p-STAT1. In vivo, db-cAMP reduced the number of M1 macrophages induced by LPS injection without changes in M2 and Mres numbers. Moreover, db-cAMP enhanced efferocytosis of apoptotic neutrophils in a PKA-dependent manner and increased the expression of Annexin A1 and CD36, two molecules associated with efferocytosis. Finally, inhibition of endogenous PKA during LPS-induced pleurisy impaired the physiological resolution of inflammation. Taken together, the results suggest that cAMP is involved in the major functions of macrophages, such as nonphlogistic recruitment, reprogramming and efferocytosis, all key processes for inflammation resolution.

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DLL1 orchestrates CD8+ T cells to induce long-term vascular normalization and tumor regression

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2020057118 ◽

2021 ◽

Vol 118 (22) ◽

pp. e2020057118

Author(s):

Naidong Zhang ◽

Rongping Yin ◽

Pei Zhou ◽

Xiaomei Liu ◽

Peng Fan ◽

...

Keyword(s):

T Cells ◽

Cancer Immunotherapy ◽

Tumor Regression ◽

Macrophage Polarization ◽

Tumor Growth Inhibition ◽

Dependent Manner ◽

Vascular Normalization ◽

Ifn Γ

The immunosuppressive and hypoxic tumor microenvironment (TME) remains a major obstacle to impede cancer immunotherapy. Here, we showed that elevated levels of Delta-like 1 (DLL1) in the breast and lung TME induced long-term tumor vascular normalization to alleviate tumor hypoxia and promoted the accumulation of interferon γ (IFN-γ)–expressing CD8+ T cells and the polarization of M1-like macrophages. Moreover, increased DLL1 levels in the TME sensitized anti-cytotoxic T lymphocyte–associated protein 4 (anti-CTLA4) treatment in its resistant tumors, resulting in tumor regression and prolonged survival. Mechanically, in vivo depletion of CD8+ T cells or host IFN-γ deficiency reversed tumor growth inhibition and abrogated DLL1-induced tumor vascular normalization without affecting DLL1-mediated macrophage polarization. Together, these results demonstrate that elevated DLL1 levels in the TME promote durable tumor vascular normalization in a CD8+ T cell– and IFN-γ–dependent manner and potentiate anti-CTLA4 therapy. Our findings unveil DLL1 as a potential target to persistently normalize the TME to facilitate cancer immunotherapy.

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Role ofβ2 Integrins in the Binding of Thymocytes to Rat Thymic Macrophages

Developmental Immunology ◽

10.1155/1994/95687 ◽

1994 ◽

Vol 4 (1) ◽

pp. 65-77 ◽

Cited By ~ 1

Author(s):

Miodrag Čolić ◽

Vesna Ilić ◽

Takuya Tamatani ◽

Masayuki Miyasaka ◽

Miloš D. Pavlović

Keyword(s):

Significant Role ◽

Inhibitory Effect ◽

Adherent Cells ◽

Experimental Conditions ◽

Tnf Α ◽

Significant Difference ◽

Ifn Γ ◽

And Function

A role of β2 integrins and one of their ligands, ICAM-1, in thymic macrophage (TMF)/thymocyte interactions was studied. TMF were isolated as adherent cells from 4-day old culture of thymic-cell suspensions either from normal or hydrocortisone-treated rats. Adherent cells were 94-98% positive with ED1 (a pan-macrophage marker). The majority of them (75-95%) expressed the CD11b and CD18 molecules, and 60-70% expressed CD54 (ICAM-1). A low proportion of TMF (10-20%) expressed CDlla (LFA-1). The expression of all these antigens was upregulated by IFN-α and TNF-α. The effect of these mAbs on TMF/thymocyte binding was studied using a simple rosette assay by incubating unstimulated or IFN-γ or TNF-α stimulated TMF, grown on microscopic slides with resting or ConA +IL-2 activated thymocytes. It was found that LFA-1/CD18 and ICAM-1 play a significant role in the TMF/thymocyte adhesion. In addition, a LFA-l-dependent/ICAM- 1-independent adhesion pathway was observed, suggesting that LFA-1 might use another ligand. The inhibitory effect of anti-CD18 mAb (WT-3) was higher than the effect of anti-LFA-1 mAb (WT-1) and was a consequence of blocking the CD18 chain both on thymocytes and TMF. No significant difference in the expression and function of adhesion molecules was found between TMF obtained from normal or hydrocortisone-treated rats. The involvement of CD1 1b in these processes was of lesser importance than the role of the CD11a molecule. By using mAbs to different epitopes of the CD11b molecule, such as OX-42 (anti-CD11b/CD11c), ED7, and ED8 (anti-CD11b), it was found that they were either slightly or moderately inhibitory under certain experimental conditions or did not significantly modulate TMF/thymocyte binding. Oχ-42 was slightly stimulatory in some experiments. Cumulatively, these results show that 2 integrins play a significant role in TMF/thymocyte interactions and probably contribute to T-cell development in vivo.

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Mitochondrial metabolism in regulating macrophage polarization: an emerging regulator of metabolic inflammatory diseases

Acta Biochimica et Biophysica Sinica ◽

10.1093/abbs/gmaa081 ◽

2020 ◽

Vol 52 (9) ◽

pp. 917-926

Author(s):

Jina Qing ◽

Zizhen Zhang ◽

Petr Novák ◽

Guojun Zhao ◽

Kai Yin

Keyword(s):

Molecular Mechanisms ◽

Inflammatory Diseases ◽

Cell Metabolism ◽

Macrophage Polarization ◽

Mitochondrial Metabolism ◽

Major Type ◽

Macrophage Phenotype ◽

M1 Macrophages ◽

Cell Functions ◽

And Function

Abstract As a major type of immune cells with heterogeneity and plasticity, macrophages are classically divided into inflammatory (M1) and alternative/anti-inflammatory (M2) types and play a crucial role in the progress of the inflammatory diseases. Recent studies have shown that metabolism is an important determinant of macrophage phenotype. Mitochondria, one of the most important compartments involving cell metabolism, are closely associated with the regulation of cell functions. In most types of cell, mitochondrial oxidative phosphorylation (OXPHOS) is the primary mode of cellular energy production. However, mitochondrial OXPHOS is inhibited in activated M1 macrophages, rendering them unable to be converted into M2 phenotype. Thus, mitochondrial metabolism is a crucial regulator in macrophage functions. This review summarizes the roles of mitochondria in macrophage polarization and analyzes the molecular mechanisms underlying mitochondrial metabolism and function, which may provide new approaches for the treatment of metabolic inflammatory diseases.

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Production of Matrix Metalloproteinases in Response to Mycobacterial Infection

Infection and Immunity ◽

10.1128/iai.69.9.5661-5670.2001 ◽

2001 ◽

Vol 69 (9) ◽

pp. 5661-5670 ◽

Cited By ~ 94

Author(s):

Marianne Quiding-Järbrink ◽

Debbie A. Smith ◽

Gregory J. Bancroft

Keyword(s):

Matrix Metalloproteinases ◽

Severe Combined Immunodeficiency ◽

Tissue Remodeling ◽

Mycobacterial Infection ◽

Dependent Manner ◽

Mycobacterial Infections ◽

Tnf Α ◽

Ifn Γ

ABSTRACT Matrix metalloproteinases (MMPs) constitute a large family of enzymes with specificity for the various proteins of the extracellular matrix which are implicated in tissue remodeling processes and chronic inflammatory conditions. To investigate the role of MMPs in immunity to mycobacterial infections, we incubated murine peritoneal macrophages with viable Mycobacterium bovis BCG or Mycobacterium tuberculosis H37Rv and assayed MMP activity in the supernatants by zymography. Resting macrophages secreted only small amounts of MMP-9 (gelatinase B), but secretion increased dramatically in a dose-dependent manner in response to either BCG or M. tuberculosis in vitro. Incubation with mycobacteria also induced increased MMP-2 (gelatinase A) activity. Neutralization of tumor necrosis alpha (TNF-α), and to a lesser extent interleukin 18 (IL-18), substantially reduced MMP production in response to mycobacteria. Exogenous addition of TNF-α or IL-18 induced macrophages to express MMPs, even in the absence of bacteria. The immunoregulatory cytokines gamma interferon (IFN-γ), IL-4, and IL-10 all suppressed BCG-induced MMP production, but through different mechanisms. IFN-γ treatment increased macrophage secretion of TNF-α but still reduced their MMP activity. Conversely, IL-4 and IL-10 seemed to act by reducing the amount of TNF-α available to the macrophages. Finally, infection of BALB/c or severe combined immunodeficiency (SCID) mice with either BCG or M. tuberculosis induced substantial increases in MMP-9 activity in infected tissues. In conclusion, we show that mycobacterial infection induces MMP-9 activity both in vitro and in vivo and that this is regulated by TNF-α, IL-18, and IFN-γ. These findings indicate a possible contribution of MMPs to tissue remodeling processes that occur in mycobacterial infections.

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Lymphangiogenesis in renal fibrosis arises from macrophages via VEGF-C/VEGFR3-dependent autophagy and polarization

Cell Death and Disease ◽

10.1038/s41419-020-03385-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Ying Zhang ◽

Conghui Zhang ◽

Lixi Li ◽

Xinjun Liang ◽

Peng Cheng ◽

...

Keyword(s):

Renal Fibrosis ◽

Macrophage Polarization ◽

Lymphatic Vessels ◽

Macrophage Phenotype ◽

M1 Macrophages ◽

M1 Macrophage ◽

Close Relationship ◽

Stage Renal Disease

AbstractInflammation plays a crucial role in the occurrence and development of renal fibrosis, which ultimately results in end-stage renal disease (ESRD). There is new focus on lymphangiogenesis in the field of inflammation. Recent studies have revealed the association between lymphangiogenesis and renal fibrosis, but the source of lymphatic endothelial cells (LECs) is not clear. It has also been reported that macrophages are involved in lymphangiogenesis through direct and indirect mechanisms in other tissues. We hypothesized that there was a close relationship between macrophages and lymphatic endothelial progenitor cells in renal fibrosis. In this study, we demonstrated that lymphangiogenesis occurred in a renal fibrosis model and was positively correlated with the degree of fibrosis and macrophage infiltration. Compared to resting (M0) macrophages and alternatively activated (M2) macrophages, classically activated (M1) macrophages predominantly transdifferentiated into LECs in vivo and in vitro. VEGF-C further increased M1 macrophage polarization and transdifferentiation into LECs by activating VEGFR3. It was suggested that VEGF-C/VEGFR3 pathway activation downregulated macrophage autophagy and subsequently regulated macrophage phenotype. The induction of autophagy in macrophages by rapamycin decreased M1 macrophage polarization and differentiation into LECs. These results suggested that M1 macrophages promoted lymphangiogenesis and contributed to newly formed lymphatic vessels in the renal fibrosis microenvironment, and VEGF-C/VEGFR3 signaling promoted macrophage M1 polarization by suppressing macrophage autophagy and then increased the transdifferentiation of M1 macrophages into LECs.

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

Infection and Immunity ◽

10.1128/iai.70.8.4247-4253.2002 ◽

2002 ◽

Vol 70 (8) ◽

pp. 4247-4253 ◽

Cited By ~ 55

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.

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Reprogrammed M1 macrophages with inhibited STAT3, STAT6 and/or SMAD3 extends lifespan of mice with experimental carcinoma

ZHurnal «Patologicheskaia fiziologiia i eksperimental`naia terapiia» ◽

10.25557/0031-2991.2017.02.4-9 ◽

2017 ◽

pp. 4-9

Author(s):

С.В. Калиш ◽

С.В. Лямина ◽

А.А. Раецкая ◽

И.Ю. Малышев

Keyword(s):

Tumor Growth ◽

Culture Medium ◽

Ehrlich Carcinoma ◽

Macrophage Phenotype ◽

M1 Macrophages ◽

M1 Macrophage ◽

Ec Cells ◽

Experimental Carcinoma

Цель исследования. Репрограммирование М1 фенотипа макрофагов с ингибированными факторами транскрипции М2 фенотипа STAT3, STAТ6 и SMAD и оценка их влияния на развитие карциномы Эрлиха (КЭ) in vitro и in vivo. Методика. Рост опухоли иницировали in vitro путем добавления клеток КЭ в среду культивирования RPMI-1640 и in vivo путем внутрибрюшинной инъекции клеток КЭ мышам. Результаты. Установлено, что M1макрофаги и in vitro, и in vivo оказывают выраженный противоопухолевый эффект, который превосходит антиопухолевые эффекты М1, M1, M1 макрофагов и цисплатина. Заключение. М1 макрофаги с ингибированными STAT3, STAT6 и/или SMAD3 эффективно ограничивают рост опухоли. Полученные данные обосновывают разработку новой технологии противоопухолевой клеточной терапии. Objective. Reprogramming of M1 macrophage phenotype with inhibited M2 phenotype transcription factors, such as STAT3, STAT6 and SMAD and assess their impact on the development of Ehrlich carcinoma (EC) in vitro and in vivo . Methods. Tumor growth in vitro was initiated by addition of EC cells in RPMI-1640 culture medium and in vivo by intraperitoneal of EC cell injection into mice. Results. It was found that M1 macrophages have a pronounced anti-tumor effect in vitro , and in vivo , which was greater than anti-tumor effects of M1, M1, M1 macrophages and cisplatin. Conclusion. M1 macrophages with inhibited STAT3, STAT6 and/or SMAD3 effectively restrict tumor growth. The findings justify the development of new anti-tumor cell therapy technology.

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Decitabine Promotes Modulation in Phenotype and Function of Monocytes and Macrophages That Drive Immune Response Regulation

Cells ◽

10.3390/cells10040868 ◽

2021 ◽

Vol 10 (4) ◽

pp. 868

Author(s):

Fabiana Albani Zambuzi ◽

Priscilla Mariane Cardoso-Silva ◽

Ricardo Cardoso Castro ◽

Caroline Fontanari ◽

Flavio da Silva Emery ◽

...

Keyword(s):

Immune Response ◽

Hematological Malignancies ◽

M2 Macrophage ◽

M2 Polarization ◽

Tnf Α ◽

Monocytes And Macrophages ◽

Ifn Γ ◽

And Function ◽

The Impact

Decitabine is an approved hypomethylating agent used for treating hematological malignancies. Although decitabine targets altered cells, epidrugs can trigger immunomodulatory effects, reinforcing the hypothesis of immunoregulation in treated patients. We therefore aimed to evaluate the impact of decitabine treatment on the phenotype and functions of monocytes and macrophages, which are pivotal cells of the innate immunity system. In vitro decitabine administration increased bacterial phagocytosis and IL-8 release, but impaired microbicidal activity of monocytes. In addition, during monocyte-to-macrophage differentiation, treatment promoted the M2-like profile, with increased expression of CD206 and ALOX15. Macrophages also demonstrated reduced infection control when exposed to Mycobacterium tuberculosis in vitro. However, cytokine production remained unchanged, indicating an atypical M2 macrophage. Furthermore, when macrophages were cocultured with lymphocytes, decitabine induced a reduction in the release of inflammatory cytokines such as IL-1β, TNF-α, and IFN-γ, maintaining IL-10 production, suggesting that decitabine could potentialize M2 polarization and might be considered as a therapeutic against the exacerbated immune response.

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POS0333 ALTERED MACROPHAGE POLARIZATION PHENOTYPES IN SYSTEMIC SCLEROSIS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.3124 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 394.1-394

Author(s):

A. Hukara ◽

M. Rudnik ◽

C. B. Rufer ◽

O. Distler ◽

P. Blyszczuk ◽

...

Keyword(s):

Systemic Sclerosis ◽

Macrophage Polarization ◽

Peritoneal Macrophages ◽

Surface Marker ◽

Surface Marker Expression ◽

Tnf Α ◽

Ifn Γ ◽

Alternatively Activated ◽

Classically Activated

Background:Fos-like 2 (Fosl-2) is a transcription factor of the AP-1 family and has a broad range in inducing cellular changes affecting fibrosis and inflammatory responses. Pathological effects of Fosl-2 have been associated with systemic sclerosis (SSc). In addition, increased expression of Fosl-2 has been detected in human SSc monocyte-derived macrophages [1]. Monocytes and macrophages play a central role in activating and propagating acute inflammation followed by pathological fibrosis and organ dysfunction. The classification of the macrophage polarization phenotype can be assigned based on the stimulus, for example into classically-activated M(LPS), and alternatively-activated M(IL-4) macrophages [2]. However, the role of the Fosl-2 transcription factor in macrophage polarization remains elusive.Objectives:To investigate the role of Fosl-2 in macrophage polarization in SSc using Fosl-2 overexpressing transgenic (Fosl-2 tg) mice and human blood-derived macrophages from SSc patients.Methods:Thiogylcolate-elicited peritoneal macrophages were isolated from wild-type (wt) and Fosl-2 tg mice. Human peripheral CD14+ blood-derived monocytes were isolated and differentiated to macrophages (hMDM) from healthy controls and SSc patients. Murine and human macrophages were polarized with LPS (10 ng/ml), LPS + recombinant mouse IFN-γ (10 ng/ml), recombinant mouse, resp. human IL-4 (10 ng/ml) or remained untreated. Macrophage surface marker expression was assessed by flow cytometry using a mouse (F4/80, CD11b, CD86, CD80, CD38, MHCII, CD206, PD-L1, PD-L2, CD36) or human (CD38, CD40, CD86, PD-L2, PD-L1, CD163, CD206) designed polarization panel. Phagocytic activity was detected with pHrodo Red E.coli particles by flow cytometry. Gene expression and secretion of pro- and anti-inflammatory markers were measured by RT-qPCR, standard ELISAs and Griess Assay for nitric oxide production.Results:After LPS stimulation, mRNA levels of IL-1β (p<0.01, n=11-12), TNF-α (p=0.05, n=11-12) and IFN-γ (p<0.05, n=7) were reduced, whereas expression of IL-10 (p<0.05, n=11-12) was enhanced in Fosl-2 tg peritoneal macrophages in comparison to wt cells. Secretion of TNF-α (p<0.01, n=9-11) and nitric oxide (p<0.01, n=9) was impaired in Fosl-2 tg peritoneal macrophages compared to wt cells after LPS stimulation. Peritoneal macrophages were analyzed directly after isolation for macrophage polarization cell surface marker expression. Fosl-2 tg peritoneal macrophages showed an increase in the F4/80+CD11b+PD-L2+CD36+ cell population (p<0.01, n=3-6) compared to peritoneal macrophages from wt mice.The expression of cell surface markers of non-polarized and IL-4 stimulated SSc hMDM (n=17) showed an increased percentage of CD40+CD86+CD206+PD-L2+CD163+ cells (p<0.05) compared to healthy control hMDM (n=7). Phagocytic activity was enhanced in SSc hMDM (n=7) compared to healthy untreated (p<0.05), LPS (p=0.05) and IL-4 (p<0.05) hMDM (n=5).Conclusion:Our animal data indicates a role of Fosl-2 in regulating macrophage polarization with a shift from a classically-activated to an alternatively-activated phenotype. Similarly, SSc hMDM resemble a functional M(IL-4) alternative macrophage phenotype.Thus, maintaining a balanced proportion of classically- and alternatively-activated macrophage phenotypes may be an effective tool to control macrophage function in SSc.References:[1]Moreno-Moral, A., et al., Changes in macrophage transcriptome associate with systemic sclerosis and mediate GSDMA contribution to disease risk. Ann Rheum Dis, 2018. 77(4): p. 596-601.[2]Kania, G., M. Rudnik, and O. Distler, Involvement of the myeloid cell compartment in fibrogenesis and systemic sclerosis. Nat Rev Rheumatol, 2019. 15(5): p. 288-302.Disclosure of Interests:Amela Hukara: None declared, Michal Rudnik: None declared, Chantal Brigitta Rufer: None declared, Oliver Distler Speakers bureau: Actelion, Bayer, Boehringer Ingelheim, Medscape, Novartis, Roche, Menarini, Mepha, MSD, iQone, Pfizer, Consultant of: Abbvie, Actelion, Acceleron Pharma, Amgen, AnaMar, Arxx Therapeutics, Bayer, Baecon Discovery, Blade Therapeutics, Boehringer, CSL Behring, ChemomAb, Corpuspharma, Curzion Pharmaceuticals, Ergonex, Galapagos NV, GSK, Glenmark Pharmaceuticals, Inventiva, Italfarmaco, iQvia, Kymera, Medac, Medscape, Mitsubishi Tanabe Pharma, MSD, Roche, Sanofi, UCB, Lilly, Target BioScience, Pfizer, Grant/research support from: Actelion, Bayer, Boehringer Ingelheim, Kymera Therapeutics, Mitsubishi Tanabe, Przemyslaw Blyszczuk: None declared, Gabriela Kania: None declared

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Modulatory Effects of Osthole on Lipopolysaccharides-Induced Inflammation in Caco-2 Cell Monolayer and Co-Cultures with THP-1 and THP-1-Derived Macrophages

Nutrients ◽

10.3390/nu13010123 ◽

2020 ◽

Vol 13 (1) ◽

pp. 123

Author(s):

Natalia K. Kordulewska ◽

Justyna Topa ◽

Małgorzata Tańska ◽

Anna Cieślińska ◽

Ewa Fiedorowicz ◽

...

Keyword(s):

Gene Expression ◽

Inflammatory Reaction ◽

Wide Spectrum ◽

Cell Monolayer ◽

In Vivo Studies ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Tnf Α

Lipopolysaccharydes (LPS) are responsible for the intestinal inflammatory reaction, as they may disrupt tight junctions and induce cytokines (CKs) secretion. Osthole has a wide spectrum of pharmacological effects, thus its anti-inflammatory potential in the LPS-treated Caco-2 cell line as well as in Caco-2/THP-1 and Caco-2/macrophages co-cultures was investigated. In brief, Caco-2 cells and co-cultures were incubated with LPS to induce an inflammatory reaction, after which osthole (150–450 ng/mL) was applied to reduce this effect. After 24 h, the level of secreted CKs and changes in gene expression were examined. LPS significantly increased the levels of IL-1β, -6, -8, and TNF-α, while osthole reduced this effect in a concentration-dependent manner, with the most significant decrease when a 450 ng/mL dose was applied (p < 0.0001). A similar trend was observed in changes in gene expression, with the significant osthole efficiency at a concentration of 450 ng/μL for IL1R1 and COX-2 (p < 0.01) and 300 ng/μL for NF-κB (p < 0.001). Osthole increased Caco-2 monolayer permeability, thus if it would ever be considered as a potential drug for minimizing intestinal inflammatory symptoms, its safety should be confirmed in extended in vitro and in vivo studies.

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