scholarly journals Flagella Facilitate Escape of Salmonella from Oncotic Macrophages

2007 ◽  
Vol 189 (22) ◽  
pp. 8224-8232 ◽  
Author(s):  
Gen-ichiro Sano ◽  
Yasunari Takada ◽  
Shinichi Goto ◽  
Kenta Maruyama ◽  
Yutaka Shindo ◽  
...  
Keyword(s):  
Cell Death ◽  
Actin Filaments ◽  
Systemic Disease ◽  
Eukaryotic Cell ◽  
Host Cells ◽  
Dependent Manner ◽  
Intracellular Parasite ◽  
Intracellular Accumulation ◽  
Serovar Typhimurium ◽  
Entire Cell

ABSTRACT The intracellular parasite Salmonella enterica serovar Typhimurium causes a typhoid-like systemic disease in mice. Whereas the survival of Salmonella in phagocytes is well understood, little has been documented about the exit of intracellular Salmonella from host cells. Here we report that in a population of infected macrophages Salmonella induces “oncosis,” an irreversible progression to eukaryotic cell death characterized by swelling of the entire cell body. Oncotic macrophages (OnMφs) are terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling negative and lack actin filaments (F-actin). The plasma membrane of OnMφs filled with bacilli remains impermeable, and intracellular Salmonella bacilli move vigorously using flagella. Eventually, intracellular Salmonella bacilli intermittently exit host cells in a flagellum-dependent manner. These results suggest that induction of macrophage oncosis and intracellular accumulation of flagellated bacilli constitute a strategy whereby Salmonella escapes from host macrophages.

scholarly journals Targeting Salmonella Typhimurium Invasion and Intracellular Survival Using Pyrogallol

2021 ◽  
Vol 12 ◽  
Author(s):  
Biruk Tesfaye Birhanu ◽  
Eon-Bee Lee ◽  
Seung-Jin Lee ◽  
Seung-Chun Park
Keyword(s):  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Efflux Pump ◽  
Intracellular Survival ◽  
Host Cells ◽  
Intracellular Bacteria ◽  
Intracellular Pathogen ◽  
Intracellular Accumulation ◽  
Protection Assay ◽  
Serovar Typhimurium

Salmonella enterica serovar Typhimurium, an intracellular pathogen, evades the host immune response mechanisms to cause gastroenteritis in animals and humans. After invading the host cells, the bacteria proliferate in Salmonella-containing vacuole (SCV) and escapes from antimicrobial therapy. Moreover, Salmonella Typhimurium develops resistance to various antimicrobials including, fluoroquinolones. Treating intracellular bacteria and combating drug resistance is essential to limit the infection rate. One way of overcoming these challenges is through combination therapy. In this study, Pyrogallol (PG), a polyphenol, is combined with marbofloxacin (MAR) to investigate its effect on Salmonella Typhimurium invasion and intracellular survival inhibition. The Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PG against Salmonella Typhimurium were 128 and 256 μg/mL, respectively. The lowest fractional inhibitory concentration (FIC) index for a combination of PG and MAR was 0.5. The gentamycin protection assay revealed that PG (30 μg/mL) alone and in combination with sub-MIC of MAR inhibited 72.75 and 76.18% of the invading bacteria in Caco-2 cells, respectively. Besides, the intracellular survival of Salmonella Typhimurium was reduced by 7.69 and 74.36% in treatment with PG alone and combined with sub-MIC of MAR, respectively, which was visualized by the confocal microscopy. PG has also shown to increase the intracellular accumulation of fluoroquinolone by 15.2 and 34.9% at 30 and 100 μg/mL concentration, respectively. Quantitative real-time PCR demonstrated PG suppressed the genetic expression of hilA, invF, sipB, and acrA by 14.6, 15.4, 13.6, and 36%, respectively. However, the downregulation of hilA, invF, sipB, and acrA increased to 80, 74.6, 78, and 70.1%, in combination with sub-MIC of MAR, respectively. Similarly, PG combined with MAR inhibited the expression of sdiA, srgE, and rck genes by 78.6, 62.8, and 61.8%, respectively. In conclusion, PG has shown antimicrobial activity against Salmonella Typhimurium alone and in combination with MAR. It also inhibited invasion and intracellular survival of the bacteria through downregulation of quorum sensing, invading virulence, and efflux pump genes. Hence, PG could be a potential antimicrobial candidate which could limit the intracellular survival and replication of Salmonella Typhimurium.

Failure of gelsolin overexpression to regulate lymphocyte apoptosis

Blood ◽  
2000 ◽  
Vol 95 (11) ◽  
pp. 3483-3488 ◽  
Author(s):  
S. Celeste Posey ◽  
Maria Paola Martelli ◽  
Toshifumi Azuma ◽  
David J. Kwiatkowski ◽  
Barbara E. Bierer
Keyword(s):  
Cell Death ◽  
Growth Factor ◽  
Actin Filaments ◽  
Caspase 3 ◽  
Apoptotic Cell ◽  
Morphological Changes ◽  
Apoptotic Cell Death ◽  
Model Systems ◽  
Dependent Manner ◽  
Amino Terminal

Abstract The actin regulatory protein gelsolin cleaves actin filaments in a calcium- and polyphosphoinositide-dependent manner. Gelsolin has recently been described as a novel substrate of the cysteinyl protease caspase-3, an effector protease activated during apoptosis. Cleavage by caspase-3 generates an amino-terminal fragment of gelsolin that can sever actin filaments independently of calcium regulation. The disruption of the actin cytoskeleton by cleaved gelsolin is hypothesized to mediate many of the downstream morphological changes associated with apoptosis. In contrast, overexpression of full-length gelsolin has also been reported to inhibit apoptotic cell death upstream of the activation of caspase-3, suggesting that gelsolin may also act prior to commitment to cell death. The authors previously observed that actin stabilization by the cell permeant agent jasplakinolide enhanced cell death upon interleukin (IL)-2 or IL-3 withdrawal from growth-factor–dependent lymphocyte cell lines, and hypothesized that actin polymerization could alter the activity of gelsolin, thus enhancing apoptosis. Here the authors show that constitutive overexpression of gelsolin did not, however, inhibit or dramatically enhance apoptotic cell death upon growth-factor withdrawal, nor did it modify sensitivity to jasplakinolide. In contrast to previous reports, overexpression of gelsolin in Jurkat T cells did not prevent or delay apoptosis induced by Fas ligation or ceramide treatment. Overexpressed gelsolin protein was cleaved during apoptosis, as seen previously in this and other cell types. In these model systems, therefore, the level of gelsolin expression was not a rate-limiting determinant in commitment to or time to the morphological changes of apoptosis.

scholarly journals Two-Component Regulators ControlhilAExpression by ControllingfimZandhilEExpression within Salmonella enterica Serovar Typhimurium

2014 ◽  
Vol 83 (3) ◽  
pp. 978-985 ◽  
Author(s):  
M. Aaron Baxter ◽  
Bradley D. Jones
Keyword(s):  
Transcriptional Activator ◽  
Negative Regulator ◽  
Host Cells ◽  
Type I ◽  
Dependent Manner ◽  
Content Type ◽  
Regulatory Systems ◽  
Two Component ◽  
Serovar Typhimurium ◽  
Type I Fimbriae

Salmonellae initiate disease through the invasion of host cells within the intestine. This ability to invade requires the coordinated action of numerous genes, many of which are found withinSalmonellapathogenicity island 1 (SPI-1). The key to this process is the ability of the bacteria to respond to the environment, thereby upregulating the necessary genes under optimal conditions. Central to the control of SPI-1 is the transcriptional activatorhilA. Work has identified at least 10 different activators and 8 different repressors responsible for the control ofhilA. We have previously shown thathilEis aSalmonella-specific negative regulator that is able to represshilAexpression and invasion. Additionally,fimZ, a transcriptional activator responsible for the expression of type I fimbriae as well as flagellar genes, has also been implicated in this process.fimZis homologous to response regulators from other two-component regulatory systems, although a sensor for the system has not been identified. ThephoPQandphoBRregulons are both two-component systems that negatively affecthilAexpression, although the mechanism of action has not been determined. Our results show that PhoBR is capable of inducingfimZexpression, whereas PhoPQ does not affectfimZexpression but does upregulatehilEin an FimZ-dependent manner. Therefore, phosphate (sensed by PhoBR) and magnesium (sensed by PhoPQ) levels are important in controllinghilAexpression levels whenSalmonellais in the intestinal environment.

scholarly journals Role of the Salmonella Pathogenicity Island 1 (SPI-1) Protein InvB in Type III Secretion of SopE and SopE2, Two Salmonella Effector Proteins Encoded Outside of SPI-1

2003 ◽  
Vol 185 (23) ◽  
pp. 6950-6967 ◽  
Author(s):  
Kristin Ehrbar ◽  
Andrea Friebel ◽  
Samuel I. Miller ◽  
Wolf-Dietrich Hardt
Keyword(s):  
Type Iii Secretion ◽  
Inflammatory Responses ◽  
Pathogenicity Island ◽  
Effector Proteins ◽  
Host Cells ◽  
Effector Protein ◽  
Dependent Manner ◽  
Type Iii ◽  
Serovar Typhimurium

ABSTRACT Salmonella enterica subspecies 1 serovar Typhimurium encodes a type III secretion system (TTSS) within Salmonella pathogenicity island 1 (SPI-1). This TTSS injects effector proteins into host cells to trigger invasion and inflammatory responses. Effector proteins are recognized by the TTSS via signals encoded in their N termini. Specific chaperones can be involved in this process. The chaperones InvB, SicA, and SicP are encoded in SPI-1 and are required for transport of SPI-1-encoded effectors. Several key effector proteins, like SopE and SopE2, are located outside of SPI-1 but are secreted in an SPI-1-dependent manner. It has not been clear how these effector proteins are recognized by the SPI-1 TTSS. Using pull-down and coimmunoprecipitation assays, we found that SopE is copurified with InvB, the known chaperone for the SPI-1-encoded effector protein Sip/SspA. We also found that InvB is required for secretion and translocation of SopE and SopE2 and for stabilization of SopE2 in the bacterial cytosol. Our data demonstrate that effector proteins encoded within and outside of SPI-1 use the same chaperone for secretion via the SPI-1 TTSS.

Failure of gelsolin overexpression to regulate lymphocyte apoptosis

Blood ◽  
2000 ◽  
Vol 95 (11) ◽  
pp. 3483-3488
Author(s):  
S. Celeste Posey ◽  
Maria Paola Martelli ◽  
Toshifumi Azuma ◽  
David J. Kwiatkowski ◽  
Barbara E. Bierer
Keyword(s):  
Cell Death ◽  
Growth Factor ◽  
Actin Filaments ◽  
Caspase 3 ◽  
Apoptotic Cell ◽  
Morphological Changes ◽  
Apoptotic Cell Death ◽  
Model Systems ◽  
Dependent Manner ◽  
Amino Terminal

The actin regulatory protein gelsolin cleaves actin filaments in a calcium- and polyphosphoinositide-dependent manner. Gelsolin has recently been described as a novel substrate of the cysteinyl protease caspase-3, an effector protease activated during apoptosis. Cleavage by caspase-3 generates an amino-terminal fragment of gelsolin that can sever actin filaments independently of calcium regulation. The disruption of the actin cytoskeleton by cleaved gelsolin is hypothesized to mediate many of the downstream morphological changes associated with apoptosis. In contrast, overexpression of full-length gelsolin has also been reported to inhibit apoptotic cell death upstream of the activation of caspase-3, suggesting that gelsolin may also act prior to commitment to cell death. The authors previously observed that actin stabilization by the cell permeant agent jasplakinolide enhanced cell death upon interleukin (IL)-2 or IL-3 withdrawal from growth-factor–dependent lymphocyte cell lines, and hypothesized that actin polymerization could alter the activity of gelsolin, thus enhancing apoptosis. Here the authors show that constitutive overexpression of gelsolin did not, however, inhibit or dramatically enhance apoptotic cell death upon growth-factor withdrawal, nor did it modify sensitivity to jasplakinolide. In contrast to previous reports, overexpression of gelsolin in Jurkat T cells did not prevent or delay apoptosis induced by Fas ligation or ceramide treatment. Overexpressed gelsolin protein was cleaved during apoptosis, as seen previously in this and other cell types. In these model systems, therefore, the level of gelsolin expression was not a rate-limiting determinant in commitment to or time to the morphological changes of apoptosis.

scholarly journals Absence of Platelet Endothelial Cell Adhesion Molecule 1, PECAM-1/CD31,In VivoIncreases Resistance to Salmonella enterica Serovar Typhimurium in Mice

2013 ◽  
Vol 81 (6) ◽  
pp. 1952-1963 ◽  
Author(s):  
Michael D. Lovelace ◽  
May Lin Yap ◽  
Jana Yip ◽  
William Muller ◽  
Odilia Wijburg ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Inflammatory Responses ◽  
Bacterial Load ◽  
Host Cells ◽  
Dependent Manner ◽  
Wild Type ◽  
Mesenteric Lymph Nodes ◽  
Serovar Typhimurium

ABSTRACTPECAM-1/CD31 is known to regulate inflammatory responses and exhibit pro- and anti-inflammatory functions. This study was designed to determine the functional role of PECAM-1 in susceptibility to murine primaryin vivoinfection withSalmonella entericaserovar Typhimurium and inin vitroinflammatory responses of peritoneal macrophages. Lectin profiling showed that cellular PECAM-1 and recombinant human PECAM-1-Ig chimera contain high levels of mannose sugars andN-acetylglucosamine. Consistent with this carbohydrate pattern, both recombinant human and murine PECAM-1-Ig chimeras were shown to bindS. Typhimurium in a dose-dependent mannerin vitro. Using oral and fecal-oral transmission models ofS. Typhimurium SL1344 infection, PECAM-1−/−mice were found to be more resistant toS. Typhimurium infection than wild-type (WT) C57BL/6 mice. While fecal shedding ofS. Typhimurium was comparable in wild-type and PECAM-1−/−mice, the PECAM-1-deficient mice had lower bacterial loads in systemic organs such as liver, spleen, and mesenteric lymph nodes than WT mice, suggesting that extraintestinal dissemination was reduced in the absence of PECAM-1. This reduced bacterial load correlated with reduced tumor necrosis factor (TNF), interleukin-6 (IL-6), and monocyte chemoattractant protein (MCP) levels in sera of PECAM-1−/−mice. Followingin vitrostimulation of macrophages with either wholeS. Typhimurium, lipopolysaccharide (LPS) (Toll-like receptor 4 [TLR4] ligand), or poly(I·C) (TLR3 ligand), production of TNF and IL-6 by PECAM-1−/−macrophages was reduced. Together, these results suggest that PECAM-1 may have multiple functions in resistance to infection withS. Typhimurium, including binding to host cells, extraintestinal spread to deeper tissues, and regulation of inflammatory cytokine production by infected macrophages.

scholarly journals Intracellular survival of Salmonella enterica serovar Typhi in human macrophages is independent of Salmonella pathogenicity island (SPI)-2

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3689-3698 ◽  
Author(s):  
Chantal G. Forest ◽  
Elyse Ferraro ◽  
Sébastien C. Sabbagh ◽  
France Daigle
Keyword(s):  
Salmonella Enterica ◽  
Systemic Disease ◽  
Distinct Type ◽  
Intracellular Survival ◽  
Effector Proteins ◽  
Host Cells ◽  
Secretion Systems ◽  
Human Macrophages ◽  
Successful Infection ◽  
Serovar Typhimurium

For successful infection, Salmonella enterica secretes and injects effector proteins into host cells by two distinct type three secretion systems (T3SSs) located on Salmonella pathogenicity islands (SPIs)-1 and -2. The SPI-2 T3SS is involved in intracellular survival of S. enterica serovar Typhimurium and systemic disease. As little is known regarding the function of the SPI-2 T3SS from S. enterica serovar Typhi, the aetiological agent of typhoid fever, we investigated its role for survival in human macrophages. Mutations in the translocon (sseB), basal secretion apparatus (ssaR) and regulator (ssrB) did not result in any reduction in survival under many of the conditions tested. Similar results were obtained with another S. Typhi strain or by using human primary cells. Results were corroborated based on complete deletion of the SPI-2 T3SS. Surprisingly, the data suggest that the SPI-2 T3SS of S. Typhi is not required for survival in human macrophages.

scholarly journals Clustered Intracellular Salmonella enterica Serovar Typhimurium Blocks Host Cell Cytokinesis

2016 ◽  
Vol 84 (7) ◽  
pp. 2149-2158 ◽  
Author(s):  
António J. M. Santos ◽  
Charlotte H. Durkin ◽  
Sophie Helaine ◽  
Emmanuel Boucrot ◽  
David W. Holden
Keyword(s):  
Cell Cycle ◽  
Epithelial Cells ◽  
Host Cell ◽  
Salmonella Enterica ◽  
Host Cells ◽  
Dependent Manner ◽  
Microtubule Organizing Center ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Chromosomal Passenger

Several bacterial pathogens and viruses interfere with the cell cycle of their host cells to enhance virulence. This is especially apparent in bacteria that colonize the gut epithelium, where inhibition of the cell cycle of infected cells enhances the intestinal colonization. We found that intracellularSalmonella entericaserovar Typhimurium induced the binucleation of a large proportion of epithelial cells by 14 h postinvasion and that the effect was dependent on an intactSalmonellapathogenicity island 2 (SPI-2) type 3 secretion system. The SPI-2 effectors SseF and SseG were required to induce binucleation. SseF and SseG are known to maintain microcolonies ofSalmonella-containing vacuoles close to the microtubule organizing center of infected epithelial cells. During host cell division, these clustered microcolonies prevented the correct localization of members of the chromosomal passenger complex and mitotic kinesin-like protein 1 and consequently prevented cytokinesis. Tetraploidy, arising from a cytokinesis defect, is known to have a deleterious effect on subsequent cell divisions, resulting in either chromosomal instabilities or cell cycle arrest. In infected mice, proliferation of small intestinal epithelial cells was compromised in an SseF/SseG-dependent manner, suggesting that cytokinesis failure caused byS. Typhimurium delays epithelial cell turnover in the intestine.

scholarly journals The Salmonella Effector SteA Contributes to the Control of Membrane Dynamics of Salmonella-Containing Vacuoles

2014 ◽  
Vol 82 (7) ◽  
pp. 2923-2934 ◽  
Author(s):  
Lia Domingues ◽  
David W. Holden ◽  
Luís Jaime Mota
Keyword(s):  
Systemic Disease ◽  
Bacterial Pathogen ◽  
Membrane Dynamics ◽  
Effector Proteins ◽  
Host Cells ◽  
Secretion Systems ◽  
Content Type ◽  
Microtubule Motors ◽  
Serovar Typhimurium ◽  
Microtubule Motor

ABSTRACTSalmonella entericaserovar Typhimurium is a bacterial pathogen causing gastroenteritis in humans and a typhoid-like systemic disease in mice.S. Typhimurium virulence is related to its capacity to multiply intracellularly within a membrane-bound compartment, theSalmonella-containing vacuole (SCV), and depends on type III secretion systems that deliver bacterial effector proteins into host cells. Here, we analyzed the cellular function of theSalmonellaeffector SteA. We show that, compared to cells infected by wild-typeS. Typhimurium, cells infected by ΔsteAmutant bacteria displayed fewerSalmonella-induced filaments (SIFs), an increased clustering of SCVs, and morphologically abnormal vacuoles containing more than one bacterium. The increased clustering of SCVs and the appearance of vacuoles containing more than one bacterium were suppressed by inhibition of the activity of the microtubule motor dynein or kinesin-1. Clustering and positioning of SCVs are controlled by the effectors SseF and SseG, possibly by helping to maintain a balanced activity of microtubule motors on the bacterial vacuoles. Deletion ofsteAinS. Typhimurium ΔsseFor ΔsseGmutants revealed that SteA contributes to the characteristic scattered distribution of ΔsseFor ΔsseGmutant SCVs in infected cells. Overall, this shows that SteA participates in the control of SCV membrane dynamics. Moreover, it indicates that SteA is functionally linked to SseF and SseG and suggests that it might contribute directly or indirectly to the regulation of microtubule motors on the bacterial vacuoles.

scholarly journals Salmonella enterica Serovar Typhimurium Induces Cell Death in Bovine Monocyte-Derived Macrophages by Early sipB-Dependent and DelayedsipB-Independent Mechanisms

2001 ◽  
Vol 69 (4) ◽  
pp. 2293-2301 ◽  
Author(s):  
Renato L. Santos ◽  
Renée M. Tsolis ◽  
Andreas J. Bäumler ◽  
Roger Smith ◽  
L. Garry Adams
Keyword(s):  
Cell Death ◽  
Stationary Phase ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Systemic Disease ◽  
Logarithmic Phase ◽  
Intracellular Pathogens ◽  
Caspase Inhibitor ◽  
Serovar Typhimurium ◽  
General Caspase Inhibitor

ABSTRACT It was previously demonstrated that Salmonella enterica serovar Typhimurium induces cell death with features of apoptosis in murine macrophages. Mice infected withSalmonella serovar Typhimurium develop systemic disease without diarrhea, whereas the infection in cattle and in humans is localized and characterized by diarrhea. Considering these clinical disease expression differences between mice and cattle, we investigated whether serovar Typhimurium is cytotoxic for bovine macrophages. Macrophages infected with serovar Typhimurium grown in the logarithmic phase quickly underwent cell death. Macrophages infected with stationary-phase cultures or with a mutant lacking sipBunderwent no immediate cell death but did develop delayed cytotoxicity, undergoing cell death between 12 and 18 h postinfection. Both pathways were temporarily blocked by the general caspase inhibitor Z-VAD-Fmk and by the caspase 1 inhibitor Z-YVAD-Fmk. Comparisons of macrophages from cattle naturally resistant or susceptible to intracellular pathogens indicated no differences between these two genetic backgrounds in terms of susceptibility to serovar Typhimurium-induced cell death. We conclude thatSalmonella serovar Typhimurium induces cell death in bovine macrophages by two distinct mechanisms, earlysipB-mediated and delayedsipB-independent mechanisms.

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