mTORC1-mediated polarization of M1 macrophages and their accumulation in the liver correlate with immunopathology in fatal ehrlichiosis

Abstract A polarized macrophage response into inflammatory (M1) or regenerative/anti-inflammatory (M2) phenotypes is critical in host response to multiple intracellular bacterial infections. Ehrlichia is an obligate Gram-negative intracellular bacterium that causes human monocytic ehrlichiosis (HME): a febrile illness that may progress to fatal sepsis with multi-organ failure. We have shown that liver injury and Ehrlichia-induced sepsis occur due to dysregulated inflammation. Here, we investigated the contribution of macrophages to Ehrlichia-induced sepsis using murine models of mild and fatal ehrlichiosis. Lethally-infected mice showed accumulation of M1 macrophages (iNOS-positive) in the liver. In contrast, non-lethally infected mice showed polarization of M2 macrophages and their accumulation in peritoneum, but not in the liver. Predominance of M1 macrophages in lethally-infected mice was associated with expansion of IL-17-producing T, NK, and NKT cells. Consistent with the in vivo data, infection of bone marrow-derived macrophages (BMM) with lethal Ehrlichia polarized M0 macrophages into M1 phenotype under an mTORC1-dependent manner, while infection with non-lethal Ehrlichia polarized these cells into M2 types. This work highlights that mTORC1-mediated polarization of macrophages towards M1 phenotype may contribute to induction of pathogenic immune responses during fatal ehrlichiosis. Targeting mTORC1 pathway may provide a novel aproach for treatment of HME.

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Enhanced Expression of miR-34a Enhances Escherichia coli Lipopolysaccharide-Mediated Endometritis by Targeting LGR4 to Activate the NF-κB Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/1744754 ◽

2021 ◽

Vol 2021 ◽

pp. 1-18

Author(s):

Xiaofei Ma ◽

Baoyi Yin ◽

Shuai Guo ◽

Talha Umar ◽

Junfeng Liu ◽

...

Keyword(s):

Escherichia Coli ◽

Bacterial Infections ◽

Luciferase Reporter ◽

Blue Staining ◽

Histopathological Analysis ◽

Dependent Manner ◽

Luciferase Reporter Gene ◽

Gram Staining

Background. Persistent endometritis caused by bacterial infections has lethal effects on the reproductive performance of dairy cattle, which compromises animal welfare and delays or prevents pregnancy. The microRNA (miRNA) miR-34 family plays a pivotal role in the inflammatory process; however, the precise mechanism of miR-34a in endometritis has not been thoroughly elucidated to date. Methods. In this study, the endometrium of cows diagnosed with endometritis was harvested for bacterial culture and Gram staining to evaluate bacterial contamination of the uterus. Based on this, a bovine endometrial epithelial cell (BEND) inflammation model and a mouse model stimulated with lipopolysaccharide (LPS) in vitro and in vivo were constructed. Cell viability was assessed by CCK-8, trypan blue staining, and flow cytometry. H&E was applied to histopathological analysis. Immunohistochemical, immunofluorescence, qRT-PCR, and western blot assays were performed to measure the mRNA and protein expression of relevant genes. Online databases, plasmid construction, and dual-luciferase reporter gene assays were used to predict and validate the interaction between miR-34a and its target gene LGR4. Finally, mice were injected vaginally with a local antagomir to validate the role of miR-34a in murine uterine inflammation. Results. In this study, we observed that Gram-negative bacteria, represented by Escherichia coli, are the predominant pathogenic agents responsible for the recurrent occurrence of endometritis in dairy cows. Further, miR-34a was found to repress the expression of LGR4 by targeting the 3 ′ untranslated region (3 ′ UTR) of LGR4. miR-34a was upregulated in bovine uterine tissues and bovine endometrial epithelial cells stimulated with LPS. miR-34a induced the release of the proinflammatory cytokines IL-1β, IL-6, and TNF-α by activating the phosphorylation of NF-κB p65. Furthermore, IL-1β upregulated miR-34a transcription and downregulated LGR4 expression in an IL-1β-dependent manner. Conclusions. Taken together, our study confirmed that miR-34a is regulated by IL-1β and suppresses the level of the LGR4 3 ′ UTR, which in turn exacerbates the inflammatory response. Thus, the knockdown of miR-34a might be a new direction for the treatment of endometritis.

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Yersinia pseudotuberculosis YopJ Limits Macrophage Response by Downregulating COX-2-Mediated Biosynthesis of PGE2 in a MAPK/ERK-Dependent Manner

Microbiology Spectrum ◽

10.1128/spectrum.00496-21 ◽

2021 ◽

Author(s):

Austin E. F. Sheppe ◽

John Santelices ◽

Daniel M. Czyz ◽

Mariola J. Edelmann

Keyword(s):

Bacterial Infection ◽

Yersinia Pseudotuberculosis ◽

Macrophage Polarization ◽

Inflammasome Activation ◽

Dependent Manner ◽

Macrophage Response ◽

M1 Phenotype ◽

Cox 2 ◽

Pathogen Clearance

PGE2 is a critical immunomodulatory lipid, but its role in bacterial infection and pathogen clearance is poorly understood. We previously demonstrated that PGE2 leads to macrophage polarization toward the M1 phenotype and stimulates inflammasome activation in infected macrophages.

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Quercetin prevents necroptosis of oligodendrocytes by inhibiting macrophages/microglia polarization to M1 phenotype after spinal cord injury in rats

Journal of Neuroinflammation ◽

10.1186/s12974-019-1613-2 ◽

2019 ◽

Vol 16 (1) ◽

Cited By ~ 8

Author(s):

Hong Fan ◽

Hai-Bin Tang ◽

Le-Qun Shan ◽

Shi-Chang Liu ◽

Da-Geng Huang ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

M1 Macrophages ◽

Qrt Pcr ◽

Cord Injury ◽

Microglia Polarization ◽

M1 Phenotype ◽

Quercetin Treatment

Abstract Background Oligodendrocytes (OLs) death after spinal cord injury (SCI) contributes to demyelination, even leading to a permanent neurological deficit. Besides apoptosis, our previous study demonstrated that OLs underwent receptor-interacting serine-threonine kinase 3(RIP3)/mixed lineage kinase domain-like protein (MLKL)-mediated necroptosis. Considering that necroptosis is always accompanied with pro-inflammatory response and quercetin has long been used as anti-inflammatory agent, in the present study we investigated whether quercetin could inhibit necroptosis of OLs and suppress the M1 macrophages/microglia-mediated immune response after SCI as well as the possible mechanism. Methods In this study, we applied quercetin, an important flavonoid component of various herbs, to treat rats with SCI and rats injected with saline were employed as the control group. Locomotor functional recovery was evaluated using Basso-Beattie-Bresnahan (BBB) scoring and rump-height Index (RHI) assay. In vivo, the necroptosis, apoptosis, and regeneration of OLs were detected by immunohistochemistry, 5′-bromo-2′-deoxyuridine (BrdU) incorporation. The loss of myelin and axons after SCI were evaluated by Luxol fast blue (LFB) staining, immunohistochemistry, and electron microscopic study. The polarization of macrophages/microglia after SCI and the underlying mechanisms were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. In vitro, the ATP and reactive oxygen species (ROS) level examination, propidium iodide (PI) labeling, and Western blotting were used to analyze the necroptosis of cultured OLs, while the signaling pathways-mediated polarization of cultured macrophages/microglia was detected by qRT-PCR and Western blotting. Results We demonstrated that quercetin treatment improved functional recovery in rats after SCI. We then found that quercetin significantly reduced necroptosis of OLs after SCI without influencing apoptosis and regeneration of OLs. Meanwhile, myelin loss and axon loss were also significantly reduced in quercetin-treated rats, as compared to SCI + saline control. Further, we revealed that quercetin could suppress macrophages/microglia polarized to M1 phenotype through inhibition of STAT1 and NF-κB pathway in vivo and in vitro, which contributes to the decreased necroptosis of OLs. Conclusions Quercetin treatment alleviated necroptosis of OLs partially by inhibiting M1 macrophages/microglia polarization after SCI. Our findings suggest that necroptosis of OLs may be a potential therapeutic target for clinical SCI.

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Protection from Lethal Gram-Positive Infection by Macrophage Scavenger Receptor–Dependent Phagocytosis

Journal of Experimental Medicine ◽

10.1084/jem.191.1.147 ◽

2000 ◽

Vol 191 (1) ◽

pp. 147-156 ◽

Cited By ~ 190

Author(s):

Christian A. Thomas ◽

Yongmei Li ◽

Tatsuhiko Kodama ◽

Hiroshi Suzuki ◽

Samuel C. Silverstein ◽

...

Keyword(s):

Bacterial Infections ◽

Critical Role ◽

Scavenger Receptor ◽

Lipoteichoic Acid ◽

Peritoneal Macrophages ◽

Type I ◽

Dependent Manner ◽

Gram Positive ◽

Gram Positive Bacteria

Infections with gram-positive bacteria are a major cause of morbidity and mortality in humans. Opsonin-dependent phagocytosis plays a major role in protection against and recovery from gram-positive infections. Inborn and acquired defects in opsonin generation and/or recognition by phagocytes are associated with an increased susceptibility to bacterial infections. In contrast, the physiological significance of opsonin-independent phagocytosis is unknown. Type I and II class A scavenger receptors (SR-AI/II) recognize a variety of polyanions including bacterial cell wall products such as lipopolysaccharide (LPS) and lipoteichoic acid (LTA), suggesting a role for SR-AI/II in innate immunity to bacterial infections. Here, we show that SR-AI/II–deficient mice (MSR-A−/−) are more susceptible to intraperitoneal infection with a prototypic gram-positive pathogen, Staphylococcus aureus, than MSR-A+/+ control mice. MSR-A−/− mice display an impaired ability to clear bacteria from the site of infection despite normal killing of S. aureus by neutrophils and die as a result of disseminated infection. Opsonin-independent phagocytosis of gram-positive bacteria by MSR-A−/− macrophages is significantly decreased although their phagocytic machinery is intact. Peritoneal macrophages from control mice phagocytose a variety of gram-positive bacteria in an SR-AI/II–dependent manner. Our findings demonstrate that SR-AI/II mediate opsonin-independent phagocytosis of gram-positive bacteria, and provide the first evidence that opsonin-independent phagocytosis plays a critical role in host defense against bacterial infections in vivo.

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IL-1β mediates miR-34a promotes bovine endometritis via LGR4-NF-κB axis

10.21203/rs.3.rs-416971/v1 ◽

2021 ◽

Author(s):

Xiaofei Ma ◽

Baoyi Yin ◽

Shuai Guo ◽

Talha Umar ◽

Junfeng Liu ◽

...

Keyword(s):

Epithelial Cell ◽

Bacterial Infections ◽

Luciferase Reporter ◽

Dependent Manner ◽

Luciferase Reporter Gene ◽

Endometrial Epithelial Cell ◽

Tnf Α ◽

Uterine Inflammation

Abstract Background Persistent endometritis lead by bacterial infections has lethal effects on the reproductive performance of dairy cattle, which not only compromise animal welfare but also delay or prevent pregnancy. MicroRNA (miRNA) miR-34 family plays a pivotal role in the inflammatory process; however, the precise mechanism of miR-34a in endometritis is still not thoroughly revealed. Methods In this study, we established bovine endometrial epithelial cell (BENDs) inflammation model and mouse model stimulation with Lipopolysaccharide (LPS) in vitro and in vivo. CCK-8 was used to assess cell viability. H&E was used to characterize morphology. Immunohistochemistry, immunofluorescence, qRT-PCR and western blot assays were performed to measure the mRNA or protein expression of related genes. Online database, plasmid construction and dual-luciferase Reporter gene assays were applied to predict and validate the interaction between miR-34a and its target gene LGR4, and mice were injected vaginally with local antagomir to validate the role of miR-34a in murine uterine inflammation. Results Here, we report that miR-34a suppresses LGR4 gene expression by targeting its 3'untranslated regions (3'UTR). The miR-34a was up-regulated in cow uterine tissues and bovine endometrial epithelial cell (BENDs) stimulation with LPS. It further induces the release of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α by activating the phosphorylation level of NF-κB p65. Furthermore, we also revealed that IL-1β was responsible for the upregulation of miR-34a transcription and downregulation of LGR4 in an IL-1β-dependent manner. Conclusions Taken together, our study confirmed that miR-34a is regulated by IL-1β and suppress the level of LGR4 3’UTR which in turn exacerbates the inflammatory response. Thus knockdown miR-34a might be a new indirection for treatment endometritis.

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BET bromodomain inhibition suppresses TH17-mediated pathology

Journal of Experimental Medicine ◽

10.1084/jem.20130376 ◽

2013 ◽

Vol 210 (11) ◽

pp. 2181-2190 ◽

Cited By ~ 154

Author(s):

Deanna A. Mele ◽

Andres Salmeron ◽

Srimoyee Ghosh ◽

Hon-Ren Huang ◽

Barbara M. Bryant ◽

...

Keyword(s):

Th17 Cells ◽

Bacterial Infections ◽

Critical Role ◽

Dependent Manner ◽

Bet Inhibitor ◽

Molecule Inhibitor ◽

Autoimmune Conditions ◽

Th17 Differentiation

Interleukin (IL) 17–producing T helper (TH17) cells have been selected through evolution for their ability to control fungal and bacterial infections. It is also firmly established that their aberrant generation and activation results in autoimmune conditions. Using a characterized potent and selective small molecule inhibitor, we show that the bromodomain and extra-terminal domain (BET) family of chromatin adaptors plays fundamental and selective roles in human and murine TH17 differentiation from naive CD4+ T cells, as well as in the activation of previously differentiated TH17 cells. We provide evidence that BET controls TH17 differentiation in a bromodomain-dependent manner through a mechanism that includes the direct regulation of multiple effector TH17-associated cytokines, including IL17, IL21, and GMCSF. We also demonstrate that BET family members Brd2 and Brd4 associate with the Il17 locus in TH17 cells, and that this association requires bromodomains. We recapitulate the critical role of BET bromodomains in TH17 differentiation in vivo and show that therapeutic dosing of the BET inhibitor is efficacious in mouse models of autoimmunity. Our results identify the BET family of proteins as a fundamental link between chromatin signaling and TH17 biology, and support the notion of BET inhibition as a point of therapeutic intervention in autoimmune conditions.

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OligoG CF-5/20 Disruption of Mucoid Pseudomonas aeruginosa Biofilm in a Murine Lung Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01721-15 ◽

2016 ◽

Vol 60 (5) ◽

pp. 2620-2626 ◽

Cited By ~ 20

Author(s):

Wang Hengzhuang ◽

Zhijun Song ◽

Oana Ciofu ◽

Edvar Onsøyen ◽

Philip D. Rye ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Bacterial Infections ◽

Infection Model ◽

Dependent Manner ◽

Clinical Value ◽

Biofilm Growth ◽

Content Type ◽

Log Reduction

ABSTRACTBiofilm growth is a universal survival strategy for bacteria, providing an effective and resilient approach for survival in an otherwise hostile environment. In the context of an infection, a biofilm provides resistance and tolerance to host immune defenses and antibiotics, allowing the biofilm population to survive and thrive under conditions that would destroy their planktonic counterparts. Therefore, the disruption of the biofilm is a key step in eradicating persistent bacterial infections, as seen in many types of chronic disease. In these studies, we used bothin vitrominimum biofilm eradication concentration (MBEC) assays and anin vivomodel of chronic biofilm infection to demonstrate the biofilm-disrupting effects of an alginate oligomer, OligoG CF-5/20. Biofilm infections were established in mice by tracheal instillation of a mucoid clinical isolate ofPseudomonas aeruginosaembedded in alginate polymer beads. The disruption of the biofilm by OligoG CF-5/20 was observed in a dose-dependent manner over 24 h, with up to a 2.5-log reduction in CFU in the infected mouse lungs. Furthermore,in vitroassays showed that 5% OligoG CF-5/20 significantly reduced the MBEC for colistin from 512 μg/ml to 4 μg/ml after 8 h. These findings support the potential for OligoG CF-5/20 as a biofilm disruption agent which may have clinical value in reducing the microbial burden in chronic biofilm infections.

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Hif-1α stabilisation polarises macrophages via cyclooxygenase/prostaglandin E2 in vivo

10.1101/536862 ◽

2019 ◽

Cited By ~ 1

Author(s):

Amy Lewis ◽

Philip M. Elks

Keyword(s):

Prostaglandin E2 ◽

Bacterial Infections ◽

Molecular Mechanisms ◽

Immune Cell ◽

Macrophage Phenotype ◽

M1 Macrophages ◽

Macrophage Polarisation ◽

Transgenic Lines ◽

Cell Phenotypes

AbstractMacrophage subtypes are poorly characterised in disease systems in vivo. The initial innate immune response to injury and infectious stimuli through M1 polarisation is important for the outcome of disease. Appropriate macrophage polarisation requires complex coordination of local microenvironmental cues and cytokine signalling to influence immune cell phenotypes. If the molecular mechanisms behind macrophage polarisation were better understood then macrophages could be pharmacologically tuned to better deal with bacterial infections, for example tuberculosis. Here, using zebrafish tnfa:GFP transgenic lines as in vivo readouts of M1 macrophages, we show that hypoxia and stabilisation of Hif-1α polarises macrophages to a tnfa expressing phenotype. We demonstrate a novel mechanism of Hif-1α mediated macrophage tnfa upregulation via a cyclooxygenase/prostaglandin E2 axis, a mechanism that is conserved in human primary macrophages. These findings uncover a novel macrophage HIF/COX/TNF axis that links microenvironmental cues to macrophage phenotype that may have implications in inflammation, infection and cancer, where hypoxia is a common microenvironmental feature and where cyclooxygenase and Tnfa are major mechanistic players.

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Antitumor Macrophage Response to Bacillus pumilus Ribonuclease (Binase)

Mediators of Inflammation ◽

10.1155/2017/4029641 ◽

2017 ◽

Vol 2017 ◽

pp. 1-11 ◽

Cited By ~ 6

Author(s):

Anna Makeeva ◽

Julian Rodriguez-Montesinos ◽

Pavel Zelenikhin ◽

Alexander Nesmelov ◽

Klaus T. Preissner ◽

...

Keyword(s):

Immune Response ◽

Bacillus Pumilus ◽

Adaptor Protein ◽

Short Exposure ◽

M2 Macrophages ◽

M1 Macrophages ◽

Macrophage Response ◽

Pathway Activation ◽

M1 Phenotype ◽

Stimulate Tumor Growth

Extracellular bacterial ribonucleases such as binase from Bacillus pumilus possess cytotoxic activity against tumor cells with a potential for clinical application. Moreover, they may induce activation of tumor-derived macrophages either into the M1-phenotype with well-documented functions in the regulation of the antitumor immune response or into M2-macrophages that may stimulate tumor growth, metastasis, and angiogenesis. In this study, binase or endogenous RNase1 (but not RNA or short oligonucleotides) stimulated the expression of activated NF-κB p65 subunit in macrophages. Since no changes in MyD88 and TRIF adaptor protein expression were observed, toll-like receptors may not be involved in RNase-related NF-κB pathway activation. In addition, short exposure (0.5 hr) to binase induced the release of cytokines such as IL-6, МСР-1, or TNF-α (but not IL-4 and IL-10), indicative for the polarization into antitumor M1-macrophages. Thus, we revealed increased expression of activated NF-κB p65 subunit in macrophages upon stimulation by binase and RNase1, but not RNA or short oligonucleotides.

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

Cells ◽

10.3390/cells9010128 ◽

2020 ◽

Vol 9 (1) ◽

pp. 128 ◽

Cited By ~ 9

Author(s):

Graziele L. Negreiros-Lima ◽

Kátia M. Lima ◽

Isabella Z. Moreira ◽

Bruna Lorrayne O. Jardim ◽

Juliana P. Vago ◽

...

Keyword(s):

Pleural Cavity ◽

Macrophage Polarization ◽

Dependent Manner ◽

Macrophage Phenotype ◽

M1 Macrophages ◽

Tnf Α ◽

Ifn Γ ◽

And Function ◽

Inflammation Resolution

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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