Differential Bacterial Survival, Replication, and Apoptosis-Inducing Ability of Salmonella Serovars within Human and Murine Macrophages

ABSTRACT Salmonella serovars are associated with human diseases that range from mild gastroenteritis to host-disseminated enteric fever. Human infections by Salmonella enterica serovar Typhi can lead to typhoid fever, but this serovar does not typically cause disease in mice or other animals. In contrast, S. enterica serovar Typhimurium and S. entericaserovar Enteritidis, which are usually linked to localized gastroenteritis in humans and some animal species, elicit a systemic infection in mice. To better understand these observations, multiple strains of each of several chosen serovars of Salmonellawere tested for the ability in the nonopsonized state to enter, survive, and replicate within human macrophage cells (U937 and elutriated primary cells) compared with murine macrophage cells (J774A.1 and primary peritoneal cells); in addition, death of the infected macrophages was monitored. The serovar Typhimurium strains all demonstrated enhanced survival within J774A.1 cells and murine peritoneal macrophages, compared with the significant, almost 100-fold declines in viable counts noted for serovar Typhi strains. Viable counts for serovar Enteritidis either matched the level of serovar Typhi (J774A.1 macrophages) or were comparable to counts for serovar Typhimurium (murine peritoneal macrophages). Apoptosis was significantly higher in J774A.1 cells infected with serovar Typhimurium strain LT2 compared to serovar Typhi strain Ty2. On the other hand, serovar Typhi survived at a level up to 100-fold higher in elutriated human macrophages and 2- to 3-fold higher in U937 cells compared to the serovar Typhimurium and Enteritidis strains tested. Despite the differential multiplication of serovar Typhi during infection of U937 cells, serovar Typhi caused significantly less apoptosis than infections with serovar Typhimurium. These observations indicate variability in intramacrophage survival and host cytotoxicity among the various serovars and are the first to show differences in the apoptotic response of distinctSalmonella serovars residing in human macrophage cells. These studies suggest that nonopsonized serovar Typhimurium enters, multiplies within, and causes considerable, acute death of macrophages, leading to a highly virulent infection in mice (resulting in death within 14 days). In striking contrast, nonopsonized serovar Typhi survives silently and chronically within human macrophages, causing little cell death, which allows for intrahost dissemination and typhoid fever (low host mortality). The type of disease associated with any particular serovar of Salmonellais linked to the ability of that serovar both to persist within and to elicit damage in a specific host's macrophage cells.

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The role of a single non-coding nucleotide in the evolution of an epidemic African clade of Salmonella

10.1101/175265 ◽

2017 ◽

Author(s):

Disa L. Hammarlöf ◽

Carsten Kröger ◽

Siân V. Owen ◽

Rocío Canals ◽

Lizeth Lacharme Lora ◽

...

Keyword(s):

Gene Expression Signature ◽

Systemic Infection ◽

Bloodstream Infections ◽

Human Infection ◽

Sub Saharan Africa ◽

Infection Model ◽

Nucleotide Polymorphisms ◽

Bacterial Survival ◽

Serovar Typhimurium ◽

Sub Saharan

Introductory ParagraphSalmonella enterica serovar Typhimurium ST313 is a relatively newly emerged sequence type that is causing a devastating epidemic of bloodstream infections across sub-Saharan Africa. Analysis of hundreds of Salmonella genomes has revealed that ST313 is closely-related to the ST19 group of S. Typhimurium that cause gastroenteritis across the world. The core genomes of ST313 and ST19 vary by just 1000 single-nucleotide polymorphisms (SNPs). We hypothesised that the phenotypic differences that distinguish African Salmonella from ST19 are caused by certain SNPs that directly modulate the transcription of virulence genes.Here we identified 3,597 transcriptional start sites (TSS) of the ST313 strain D23580, and searched for a gene expression signature linked to pathogenesis of Salmonella. We identified a SNP in the promoter of the pgtE gene that caused high expression of the PgtE virulence factor in African S. Typhimurium, increased the degradation of the factor B component of human complement, contributed to serum resistance and modulated virulence in the chicken infection model. The PgtE protease is known to mediate systemic infection in animal models. We propose that high levels of expression PgtE of by African S. Typhimurium ST313 promotes bacterial survival and bacterial dissemination during human infection.Our finding of a functional role for an extra-genic SNP shows that approaches used to deduce the evolution of virulence in bacterial pathogens should include a focus on non-coding regions of the genome.

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Antimicrobial activities of benzoxazinorifamycin (KRM-1648) and clarithromycin against Mycobacterium avium-intracellulare complex within murine peritoneal macrophages, human macrophage-like cells and human alveolar epithelial cells

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/43.3.351 ◽

1999 ◽

Vol 43 (3) ◽

pp. 351-357 ◽

Cited By ~ 15

Author(s):

K. Sato

Keyword(s):

Epithelial Cells ◽

Mycobacterium Avium ◽

Antimicrobial Activities ◽

Peritoneal Macrophages ◽

Alveolar Epithelial Cells ◽

Human Macrophage ◽

Alveolar Epithelial ◽

Mycobacterium Avium Intracellulare ◽

Murine Peritoneal Macrophages ◽

Human Alveolar Epithelial Cells

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Contribution of the stg Fimbrial Operon of Salmonella enterica Serovar Typhi during Interaction with Human Cells

Infection and Immunity ◽

10.1128/iai.00674-07 ◽

2007 ◽

Vol 75 (11) ◽

pp. 5264-5271 ◽

Cited By ~ 23

Author(s):

Chantal Forest ◽

Sébastien P. Faucher ◽

Katherine Poirier ◽

Sébastien Houle ◽

Charles M. Dozois ◽

...

Keyword(s):

Epithelial Cells ◽

Typhoid Fever ◽

Salmonella Enterica ◽

Stop Codon ◽

Premature Stop Codon ◽

Etiologic Agent ◽

Host Cells ◽

Human Macrophages ◽

Serovar Typhimurium ◽

K 12

ABSTRACT Salmonella serovars contain a wide variety of putative fimbrial systems that may contribute to colonization of specific niches. Salmonella enterica serovar Typhi is the etiologic agent of typhoid fever and is a pathogen specific to humans. In a previous study, we identified a gene, STY3920 (stgC), encoding the predicted usher of the stg fimbrial operon, that was expressed by serovar Typhi during infection of human macrophages. The stg genes are located in the glmS-pstS intergenic region in serovar Typhi and certain Escherichia coli strains, but they are absent in other S. enterica serovars. We cloned the stg fimbrial operon into a nonfimbriate E. coli K-12 strain and into S. enterica serovar Typhimurium. We demonstrated that the stg fimbrial operon contributed to increased adherence to human epithelial cells. Transcriptional fusion assays with serovar Typhi suggested that stg is preferentially expressed in minimal medium. Deletion of stg reduced adherence of serovar Typhi to epithelial cells. However, deletion of stg increased uptake of serovar Typhi by human macrophages, and overexpression of stg in serovar Typhi and serovar Typhimurium strains reduced phagocytosis by human macrophages. These strains survived inside macrophages as well as the wild-type parent. Although the stgC gene contains a premature stop codon that disrupts the expected open reading frame encoding the usher and is therefore considered a pseudogene, our results show that the stg operon may encode a functional fimbria. Thus, this serovar Typhi-specific fimbrial operon contributes to interactions with host cells, and further characterization is important for understanding the role of the stg fimbrial cluster in typhoid fever pathogenesis.

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Characterization of a Novel Intracellularly Activated Gene from Salmonella enterica Serovar Typhi

Infection and Immunity ◽

10.1128/iai.70.10.5404-5411.2002 ◽

2002 ◽

Vol 70 (10) ◽

pp. 5404-5411 ◽

Cited By ~ 6

Author(s):

Holger Basso ◽

Faiza Rharbaoui ◽

Lothar H. Staendner ◽

Eva Medina ◽

Francisco García-Del Portillo ◽

...

Keyword(s):

Salmonella Enterica ◽

Lethal Dose ◽

Human Monocyte ◽

Integral Membrane Protein ◽

Intracellular Survival ◽

Peritoneal Macrophages ◽

Bacterial Invasion ◽

Bacterial Survival ◽

Human Macrophages

ABSTRACT A Salmonella enterica serovar Typhi gene that is selectively up-regulated upon bacterial invasion of eukaryotic cells was characterized. The open reading frame encodes a 298-amino-acid hydrophobic polypeptide (30.8 kDa), which is predicted to be an integral membrane protein with nine membrane-spanning domains. The protein is closely related (87 to 94% reliability) to different transport and permease systems. Gene expression under laboratory conditions was relatively weak; however, sevenfold induction was observed in a high-osmolarity medium (300 mM NaCl). The growth pattern in a laboratory medium of a serovar Typhi strain Ty2 derivative containing a 735-bp in-frame deletion in this gene, named gaiA (for gene activated intracellularly), was not affected. In contrast, the mutant was partially impaired in intracellular survival in murine peritoneal macrophages, as well as in human monocyte-derived macrophages. However, in the case of human macrophages, this survival defect was modest and evident only at late infection times (24 h). Despite the distinct intracellular survival kinetics displayed in macrophages of different species, the gaiA null mutant was significantly affected in its potential to trigger apoptosis in both murine and human macrophages. Provision of the gaiA gene in trans resulted in complementation of these phenotypes. Interestingly, the absence of a functional gaiA gene caused a marked attenuation in the mouse mucin model, as shown by the increase (3 orders of magnitude) in the 50% lethal dose of the mutant strain over that of the parental strain Ty2 (P ≤ 0.05). Altogether, these data indicate that the product encoded by the gaiA gene is required for triggering apoptosis and bacterial survival within murine macrophages, which is consistent with the in vivo results obtained in the mouse mucin model. However, gaiA was not required for initial intracellular survival in human cells, indicating that its role in the natural host might be more complex than is suggested by the studies performed in the murine system.

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Synergistic activation of 2-deoxy-d-glucose uptake in rat and murine peritoneal macrophages by human macrophage colony-stimulating factor-stimulated coupling between transport and hexokinase activity and phorbol-dependent stimulation of pentose phosphate-shunt activity

Biochemical Journal ◽

10.1042/bj2650243 ◽

1990 ◽

Vol 265 (1) ◽

pp. 243-249 ◽

Cited By ~ 9

Author(s):

R J Rist ◽

G E Jones ◽

R J Naftalin

Keyword(s):

Peritoneal Macrophages ◽

Pentose Phosphate ◽

Human Macrophage ◽

Colony Stimulating Factor ◽

Hexokinase Activity ◽

Macrophage Colony Stimulating Factor ◽

Murine Peritoneal Macrophages ◽

Macrophage Colony ◽

Stimulating Factor ◽

Pentose Phosphate Shunt

1. Transport and accumulation of 2-deoxy-D-glucose (2dGlc) in rat and murine peritoneal macrophages were investigated by using C-1-3H-labelled and C-2,6-3H-labelled 2dGlc. 2. There was active accumulation of both C-1- and C-2,6-labelled 2dGlc by quiescent rat and murine macrophages via a phloretin-inhibitable transport system. 3. The rate of uptake and accumulation of 2dGlc (C-1 label) was increased by exposure to human macrophage colony-stimulating factor (mCSF-1) (1000 units/ml) in both murine and rat macrophages. This indicates that mCSF-1 enhances coupling between hexokinase activity and glucose transport at the endofacial surface of the transporter. 4. Phorbol 12-myristate 13-acetate (‘phorbol’) at 40 nM stimulated 2dGlc in rat macrophages entirely by increasing the C-2,6 label uptake. This indicates that phorbol stimulates 2dGlc uptake mainly by increasing the activity of the pentose phosphate pathway. 5. Simultaneous exposure to phorbol and mCSF-1 stimulates 2dGlc uptake to a greater extent than found with either phorbol or mCSF-1 alone. This result is explained by a simultaneous enhancement of pentose phosphate-pathway activity and of hexokinase activity acting at the endofacial surface of the cell membrane. The dual activation of these serial processes coupled to the loss of the reaction products of the pentose phosphate-shunt pathway from the cells in the form of reactive oxygen intermediates, protons and CO2 could explain the synergistic action of phorbol and mCSF-1 in activation of sugar transport in macrophages.

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Mechanisms Involved in Apoptosis of Human Macrophages Induced by Lipopolysaccharide from Actinobacillus actinomycetemcomitans in the Presence of Cycloheximide

Infection and Immunity ◽

10.1128/iai.72.4.1856-1865.2004 ◽

2004 ◽

Vol 72 (4) ◽

pp. 1856-1865 ◽

Cited By ~ 27

Author(s):

Takao Suzuki ◽

Makoto Kobayashi ◽

Kyoko Isatsu ◽

Tatsuji Nishihara ◽

Toshihiro Aiuchi ◽

...

Keyword(s):

Molecular Mechanisms ◽

Caspase 3 ◽

Actinobacillus Actinomycetemcomitans ◽

Human Macrophage ◽

U937 Cells ◽

Apoptotic Pathway ◽

Necrosis Factor Alpha ◽

Human Macrophages ◽

Induced Apoptosis

ABSTRACT Actinobacillus actinomycetemcomitans is a major periodontopathic bacterium with multiple virulence factors, including lipopolysaccharide (LPS). Previous reports have demonstrated that LPS induced apoptosis in a murine macrophage-like cell line, J744.1, as well as in peritoneal macrophages from C3H/HeN mice in the presence of cycloheximide (CHX). However, the detailed molecular mechanisms involved in the apoptosis of macrophages induced by LPS and CHX are not well known. To clarify the possible role of LPS in the induction of macrophage apoptosis, we investigated cell death induced by LPS from A. actinomycetemcomitans and CHX in human macrophage-like U937 cells, which were differentiated by 12-O-tetradecanoylphorbol 13-acetate (TPA), and also assessed the molecular mechanisms involved in the process. We found that TPA-differentiated U937 cells usually showed resistance to LPS-induced apoptosis. However, in the presence of CHX, LPS induced release of cytochrome c without modifying steady-state levels of Bcl-2, Bcl-xL, Bax, and Bak. Treatment with LPS in the presence of CHX also led to activation of caspase-3 and apoptosis via, in part, the CD14/toll-like receptor 4 (TLR4). The induction of cytochrome c release may have been due to dephosphorylation of Akt and Bad, which were cooperatively induced by CHX and LPS. However, endogenous tumor necrosis factor alpha- and Fas-induced signals, extracellular signal-regulated kinase kinase/mitogen-activated protein kinases and I-κBα/nuclear factor-κB (NF-κB) were not required for caspase-3-dependent apoptosis. These results emphasize the possible important role of the mitochondrial apoptotic pathway leading to caspase-3 activation in LPS-induced apoptosis of human macrophages in the presence of CHX.

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