Dataset Information

Hemophagocytic macrophages in murine typhoid fever have an anti-inflammatory phenotype.

ABSTRACT: Histiocytes are white blood cells of the monocytic lineage and include macrophages and dendritic cells. In patients with a variety of infectious and noninfectious inflammatory disorders, histiocytes can engulf nonapoptotic leukocytes and nonsenescent erythrocytes and thus become hemophagocytes. We report here the identification and characterization of splenic hemophagocytes in a natural model of murine typhoid fever. The development of a flow-cytometric method allowed us to identify hemophagocytes based on their greater than 6N (termed 6N+) DNA content. Characterization of the 6N+ population from infected mice showed that these cells consist primarily of macrophages rather than dendritic cells and contain T lymphocytes, consistent with hemophagocytosis. Most 6N+ macrophages from Salmonella enterica serovar Typhimurium-infected mice contain intact DNA, consistent with hemophagocytosis. In contrast, most 6N+ macrophages from control mice or mice infected with a different bacterial pathogen, Yersinia pseudotuberculosis, contain damaged DNA. Finally, 6N+ splenic macrophages from S. Typhimurium-infected mice express markers consistent with an anti-inflammatory M2 activation state rather than a classical M1 activation state. We conclude that macrophages are the predominant splenic hemophagocyte in this disease model but not in Y. pseudotuberculosis-infected mice. The anti-inflammatory phenotype of hemophagocytic macrophages suggests that these cells contribute to the shift from acute to chronic infection.

SUBMITTER: McCoy MW

PROVIDER: S-EPMC3457584 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Hemophagocytic macrophages in murine typhoid fever have an anti-inflammatory phenotype.

McCoy Melissa W MW Moreland Sarah M SM Detweiler Corrella S CS

Infection and immunity 20120806 10

Histiocytes are white blood cells of the monocytic lineage and include macrophages and dendritic cells. In patients with a variety of infectious and noninfectious inflammatory disorders, histiocytes can engulf nonapoptotic leukocytes and nonsenescent erythrocytes and thus become hemophagocytes. We report here the identification and characterization of splenic hemophagocytes in a natural model of murine typhoid fever. The development of a flow-cytometric method allowed us to identify hemophagocyt ...[more]

PMID: 22868497

Similar Datasets

Project description:Defense and protection to multiple harmful stimuli are the inflammation, when is self-amplified and uncontrolled is the basis of the pathogenesis of a wide variety of inflammatory illness. The aim of this study was to evaluate if Petiveria alliacea could attenuate inflammation in a murine model of RAW264 macrophages the involved model and its involved mechanism.The ethanol extract from P. alliacea was precipitated with water and supernatant was used for this study (PW). The anti-inflammatory effects of PW were investigated through evaluating of the production of several cytokines, chemokines, and expression of nuclear factor-kappa B (NF-κB) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Also was determined the ability to decrease the oxidative stress in RAW264.7 cells with carboxy-2',7'-dichloro-dihydro-fluorescein diacetate.PW significantly suppress the secretion of prostaglandin E2, leukotriene C4, interleukin (IL)-1 β, IL-6, IL-10, interferon gamma nitric oxide (NO), inducible NO synthase, IL-1 β, IL-4, in RAW264.7 cells in a dose-dependent manner. In addition, PW also markedly inhibited the transcriptional activity of NF-κB. PW produced significant anti-inflammatory activity through inhibiting the production of inflammatory mediators through the NF-κB inactivation in the LPS-stimulated RAW24.7 cells.PW exerts significant antioxidant and anti-inflammatory activities, and this effect can be attributed in part, to the presence of dibenzyl disulfide, dibenzyl trisulfide pinitol, coumarin, myricetin, glutamyl-S-benzyl cysteine, and petiveriins A and B.Treatment with ethanol extract from Petiveria alliacea which was previously precipitated with water and supernatant (PE) was tested in LPS-stimulated RAW264.7 cells. PE suppressed the level of oxidative stress and the induction of proinflammatory mediators, as PGE2, LTC4, IL-1 ß, IL-6, IL-10, IFN- NO, iNOS, IL-1 ß, IL-4, in RAW264.7 macrophages through NF-B inactivation. These findings suggest that P. alliacea affords promising therapeutic in inflammatory diseases. Abbreviation used: COX-2: Ciclooxigenasa 2; DCFHDA: Carboxy-2',7'-dichloro-dihydro-fluorescein diacetate; DMEM: Dulbecco's modified eagle's medium; FBS: Fetal bovine serum; HSP70: Heat shock protein; IFN-γ: Interferon gamma; IL-1 β: Interleukin 1 β, IL-6: Interleukin 6; IL-10: Interleukin 10; IL-4: Interleukin 4; iNOS: Nitric oxide synthase; KCl: Potassium chloride; LPS: Lipopolysaccharides; LTC4: leukotriene C 4; MgCl2: Magnesium chloride; MTT: 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide; NF-κB: Nuclear factor kappa-light-chain-enhancer of activated B-cells or transcriptional activity of nuclear factor-kB; NO: Nitric oxide; PBS: Phosphate-buffered saline; PGE2: Prostaglandin E2, PMSF: Phenylmethylsulfonyl fluoride; PTC: Chloroform extract from Petiveria alliacea; PE: Ethanol extract from Petiveria alliacea; PTH: Hexane extract from Petiveria alliacea; PW: Supernatant of PTE precipitated with water; RAW264.7: Cell line murine macrophages; ROS: Reactive oxygen species; TNF-α: Tumor necrosis factor.

Project description:Murine norovirus (MNV) infection results in a late translation shutoff that is proposed to contribute to the attenuated and delayed innate immune response observed both in vitro and in vivo. Recently, we further demonstrated the activation of the α subunit of eukaryotic initiation factor 2 (eIF2α) kinase GCN2 during MNV infection, which has been previously linked to immunomodulation and resistance to inflammatory signaling during metabolic stress. While viral infection is usually associated with activation of double-stranded RNA (dsRNA) binding pattern recognition receptor PKR, we hypothesized that the establishment of a metabolic stress in infected cells is a proviral event, exploited by MNV to promote replication through weakening the activation of the innate immune response. In this study, we used multi-omics approaches to characterize cellular responses during MNV replication. We demonstrate the activation of pathways related to the integrated stress response, a known driver of anti-inflammatory phenotypes in macrophages. In particular, MNV infection causes an amino acid imbalance that is associated with GCN2 and ATF2 signaling. Importantly, this reprogramming lacks the features of a typical innate immune response, with the ATF/CHOP target GDF15 contributing to the lack of antiviral responses. We propose that MNV-induced metabolic stress supports the establishment of host tolerance to viral replication and propagation. IMPORTANCE During viral infection, host defenses are typically characterized by the secretion of proinflammatory autocrine and paracrine cytokines, potentiation of the interferon (IFN) response, and induction of the antiviral response via activation of JAK and Stat signaling. To avoid these and propagate, viruses have evolved strategies to evade or counteract host sensing. In this study, we demonstrate that murine norovirus controls the antiviral response by activating a metabolic stress response that activates the amino acid response and impairs inflammatory signaling. This highlights novel tools in the viral countermeasures arsenal and demonstrates the importance of the currently poorly understood metabolic reprogramming occurring during viral infections.

Dataset Information

Hemophagocytic macrophages in murine typhoid fever have an anti-inflammatory phenotype.

Publications

Hemophagocytic macrophages in murine typhoid fever have an anti-inflammatory phenotype.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure