scholarly journals Salmonella enterica serovar Typhimurium sseK3 induce cell apoptosis and enhance glycolysis in macrophages

2019 ◽  
Author(s):  
Fuyu Du ◽  
Chuan Yu ◽  
Chunjie Zhang ◽  
Yinju Li ◽  
Chengshui Liao ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Acid Level ◽  
Caspase 3 ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Caspase 8 ◽  
Lactic Acid Level ◽  
Wild Type ◽  
Caspase 9 ◽  
Serovar Typhimurium ◽  
The Relationship

Abstract Background: Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important infectious disease pathogen. Previous studies have identified that S. Typhimurium secreted effector K3 (SseK3) is a novel translated and secreted protein, but it is unclear whether this protein exerts a significant role in the progress of apoptosis and glycolysis in macrophages. Results: The S. Typhimurium SL1344 wild-type (WT) group, ΔsseK3 mutant group and sseK3-complemented group were used to infect macrophages and the effects of sseK3 on apoptosis and glycolysis of macrophages were investigated. The adherence and invasion of ΔsseK3 mutant group for macrophages were similar to WT group and sseK3-complemented group, indicating that SseK3 did not play an important role in the adherence and invasion of S. Typhimurium for macrophages. However, the apoptosis percentage of the ΔsseK3 mutant group was much lower than WT group and sseK3-complemented group using flow cytometry. The caspase-3, caspase-8 and caspase-9 enzyme activity of the ΔsseK3 mutant group were decreased significantly compared with WT group and sseK3-complemented group, which suggested that sseK3 could improve the activities of caspase-3, caspase-8 and caspase-9 enzyme. We also found that the pyruvic acid level did not significantly change among ΔsseK3 mutant group, WT group and sseK3-complemented group, but the lactic acid level of ΔsseK3 mutant group was much lower than WT group and sseK3-complemented group. The ATP level of ΔsseK3 mutant group was remarkably higher than WT group and sseK3-complemented group. These indicated that the sseK3 enhanced the level of glycolysis of macrophages infected by S. Typhimurium. Conclusions: Our data showed that the sseK3 of S. Typhimurium can promote macrophages apoptosis and influence glycolysis levels of macrophages. These results may give a better clue about the relationship between apoptosis and glycolysis in macrophages induced by S. Typhimurium sseK3. Keywords: S. Typhimurium, sseK3, macrophages apoptosis, glycolysis

scholarly journals The Salmonella enterica serovar Typhimurium sseK3 induce cell apoptosis and enhance glycolysis in macrophages

2020 ◽  
Author(s):  
Chuan Yu ◽  
Fuyu Du ◽  
Chunjie Zhang ◽  
Yinju Li ◽  
Chengshui Liao ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Acid Level ◽  
Caspase 3 ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Caspase 8 ◽  
Wild Type ◽  
Caspase 9 ◽  
Serovar Typhimurium ◽  
The Relationship

Abstract Background: Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important infectious disease pathogen. Recently, there are increasing researches about the relationship between apoptosis and glycolysis of cells. Previous studies have identified that S. Typhimurium secreted effector K3 (SseK3) is a novel translated and secreted protein. However, there is no study about the role of sseK3 in the relationship between apoptosis and glycolysis of cells infected with S. Typhimurium. It is unclear whether this protein exerts a significant role in the progress of apoptosis and glycolysis in macrophages. Results: The S. Typhimurium SL1344 wild-type (WT) group, ΔsseK3 mutant group and sseK3-complemented group were used to infect macrophages and the effects of sseK3 on apoptosis and glycolysis of macrophages were investigated. The adherence and invasion of ΔsseK3 mutant group for macrophages were similar to WT group and sseK3-complemented group, indicating that SseK3 did not play an important role in the adherence and invasion of S. Typhimurium for macrophages. However, the apoptosis percentage of the ΔsseK3 mutant group was much lower than WT group and sseK3-complemented group using flow cytometry. The caspase-3, caspase-8 and caspase-9 enzyme activity of the ΔsseK3 mutant group were decreased significantly compared with WT group and sseK3-complemented group, which suggested that sseK3 could improve the activities of caspase-3, caspase-8 and caspase-9 enzyme. We also found that the pyruvic acid level did not significantly change among ΔsseK3 mutant group, WT group and sseK3-complemented group, but the lactic acid level of ΔsseK3 mutant group was much lower than WT group and sseK3-complemented group. The ATP level of ΔsseK3 mutant group was remarkably higher than WT group and sseK3-complemented group. These indicated that the sseK3 enhanced the level of glycolysis of macrophages infected by S. Typhimurium. Conclusions: Our data showed that the sseK3 of S. Typhimurium involved in promoting macrophages apoptosis and influencing glycolysis levels of macrophages. These results may give a better clue about the relationship between apoptosis and glycolysis in macrophages induced by S. Typhimurium sseK3.

scholarly journals Salmonella enterica serovar Typhimurium sseK3 induces apoptosis and enhances glycolysis in macrophages

2020 ◽  
Author(s):  
Chuan Yu ◽  
Fuyu Du ◽  
Chunjie Zhang ◽  
Yinju Li ◽  
Chengshui Liao ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Salmonella Enterica ◽  
Caspase 3 ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Caspase 8 ◽  
Wild Type ◽  
Caspase 9 ◽  
Serovar Typhimurium ◽  
The Relationship

Abstract Background: Salmonella enterica serovar Typhimurium ( S. Typhimurium) is an important infectious disease pathogen that can survive and replicate in macrophages. Glycolysis is essential for immune responses against S. Typhimurium infection in macrophages, and is also associated with apoptosis. S. Typhimurium secreted effector K3 (SseK3) was recently identified as a novel translated and secreted protein. However, there is no study about the role of sseK3 in the relationship between apoptosis and glycolysis in cells infected with S. Typhimurium. It is unclear whether this protein exerts a significant role in the progress of apoptosis and glycolysis in S. Typhimurium-infected macrophages. Results: Macrophages were infected with S. Typhimurium SL1344 wild-type (WT), Δ sseK3 mutant or sseK3 -complemented strain, and the effects of sseK3 on apoptosis and glycolysis were determined. The adherence and invasion in the Δ sseK3 mutant group were similar to that in the WT and sseK3 -complemented groups, indicating that SseK3 was not essential for the adherence and invasion of S. Typhimurium in macrophages. However, the percentage of apoptosis in the Δ sseK3 mutant group was much lower than that in the WT and sseK3 -complemented groups. Caspase-3, caspase-8, and caspase-9 enzyme activity in the Δ sseK3 mutant group were significantly lower than in the WT group and sseK3 -complemented groups, indicating that sseK3 could improve the caspase-3, caspase-8, and caspase-9 enzyme activity. We also found that there were no significant differences in pyruvic acid levels between the three groups, but the lactic acid level in the Δ sseK3 mutant group was much lower than that in the WT and sseK3 -complemented groups. The ATP levels in the Δ sseK3 mutant group were remarkably higher than those in the WT and sseK3 -complemented groups. These indicated that the sseK3 enhanced the level of glycolysis in macrophages infected by S. Typhimurium. Conclusions: S. Typhimurium sseK3 is likely involved in promoting macrophage apoptosis and modulating glycolysis in macrophages. Our results could improve our understanding of the relationship between apoptosis and glycolysis in macrophages induced by S. Typhimurium sseK3 .

scholarly journals Salmonella enterica serovar Typhimurium sseK3 induces apoptosis and enhances glycolysis in macrophages

2020 ◽  
Author(s):  
Chuan Yu ◽  
Fuyu Du ◽  
Chunjie Zhang ◽  
Yinju Li ◽  
Chengshui Liao ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Salmonella Enterica ◽  
Caspase 3 ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Caspase 8 ◽  
Wild Type ◽  
Caspase 9 ◽  
Serovar Typhimurium ◽  
The Relationship

Abstract Background: Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important infectious disease pathogen that can survive and replicate in macrophages. Glycolysis is essential for immune responses against S. Typhimurium infection in macrophages, and is also associated with apoptosis. S. Typhimurium secreted effector K3 (SseK3) was recently identified as a novel translated and secreted protein. However, there is no study about the role of sseK3 in the relationship between apoptosis and glycolysis in cells infected with S. Typhimurium. It is unclear whether this protein exerts a significant role in the progress of apoptosis and glycolysis in S. Typhimurium-infected macrophages.Results: Macrophages were infected with S. Typhimurium SL1344 wild-type (WT), ΔsseK3 mutant or sseK3-complemented strain, and the effects of sseK3 on apoptosis and glycolysis were determined. The adherence and invasion in the ΔsseK3 mutant group were similar to that in the WT and sseK3-complemented groups, indicating that SseK3 was not essential for the adherence and invasion of S. Typhimurium in macrophages. However, the percentage of apoptosis in the ΔsseK3 mutant group was much lower than that in the WT and sseK3-complemented groups. Caspase-3, caspase-8, and caspase-9 enzyme activity in the ΔsseK3 mutant group were significantly lower than in the WT group and sseK3-complemented groups, indicating that sseK3 could improve the caspase-3, caspase-8, and caspase-9 enzyme activity. We also found that there were no significant differences in pyruvic acid levels between the three groups, but the lactic acid level in the ΔsseK3 mutant group was much lower than that in the WT and sseK3-complemented groups. The ATP levels in the ΔsseK3 mutant group were remarkably higher than those in the WT and sseK3-complemented groups. These indicated that the sseK3 enhanced the level of glycolysis in macrophages infected by S. Typhimurium.Conclusions: S. Typhimurium sseK3 is likely involved in promoting macrophage apoptosis and modulating glycolysis in macrophages. Our results could improve our understanding of the relationship between apoptosis and glycolysis in macrophages induced by S. Typhimurium sseK3.

scholarly journals A network of Rab GTPases controls phagosome maturation and is modulated by Salmonella enterica serovar Typhimurium

2007 ◽  
Vol 176 (3) ◽  
pp. 263-268 ◽  
Author(s):  
Adam C. Smith ◽  
Won Do Heo ◽  
Virginie Braun ◽  
Xiuju Jiang ◽  
Chloe Macrae ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Dominant Negative ◽  
Rab Gtpases ◽  
Wild Type ◽  
Intracellular Growth ◽  
Non Invasive ◽  
Serovar Typhimurium ◽  
Guanosine Triphosphatase ◽  
Kinetics Of

Members of the Rab guanosine triphosphatase (GTPase) family are key regulators of membrane traffic. Here we examined the association of 48 Rabs with model phagosomes containing a non-invasive mutant of Salmonella enterica serovar Typhimurium (S. Typhimurium). This mutant traffics to lysosomes and allowed us to determine which Rabs localize to a maturing phagosome. In total, 18 Rabs associated with maturing phagosomes, each with its own kinetics of association. Dominant-negative mutants of Rab23 and 35 inhibited phagosome–lysosome fusion. A large number of Rab GTPases localized to wild-type Salmonella-containing vacuoles (SCVs), which do not fuse with lysosomes. However, some Rabs (8B, 13, 23, 32, and 35) were excluded from wild-type SCVs whereas others (5A, 5B, 5C, 7A, 11A, and 11B) were enriched on this compartment. Our studies demonstrate that a complex network of Rab GTPases controls endocytic progression to lysosomes and that this is modulated by S. Typhimurium to allow its intracellular growth.

scholarly journals Salmonella enterica Serovar Typhimurium Uses PbgA/YejM To Regulate Lipopolysaccharide Assembly during Bacteremia

2019 ◽  
Vol 88 (1) ◽  
Author(s):  
Melina B. Cian ◽  
Nicole P. Giordano ◽  
Revathi Masilamani ◽  
Keaton E. Minor ◽  
Zachary D. Dalebroux
Keyword(s):  
Salmonella Enterica ◽  
Lipid A ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Transmembrane Domain ◽  
Wild Type ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Periplasmic Domain ◽  
Inner Membrane Protein ◽  
Substitution Mutations

ABSTRACT Salmonella enterica serovar Typhimurium (S. Typhimurium) relies upon the inner membrane protein PbgA to enhance outer membrane (OM) integrity and promote virulence in mice. The PbgA transmembrane domain (residues 1 to 190) is essential for viability, while the periplasmic domain (residues 191 to 586) is dispensable. Residues within the basic region (residues 191 to 245) bind acidic phosphates on polar phospholipids, like for cardiolipins, and are necessary for salmonella OM integrity. S. Typhimurium bacteria increase their OM cardiolipin concentrations during activation of the PhoPQ regulators. The mechanism involves PbgA’s periplasmic globular region (residues 245 to 586), but the biological role of increasing cardiolipins on the surface is not understood. Nonsynonymous polymorphisms in three essential lipopolysaccharide (LPS) synthesis regulators, lapB (also known as yciM), ftsH, and lpxC, variably suppressed the defects in OM integrity, rifampin resistance, survival in macrophages, and systemic colonization of mice in the pbgAΔ191–586 mutant (in which the PbgA periplasmic domain from residues 191 to 586 is deleted). Compared to the OMs of the wild-type salmonellae, the OMs of the pbgA mutants had increased levels of lipid A-core molecules, cardiolipins, and phosphatidylethanolamines and decreased levels of specific phospholipids with cyclopropanated fatty acids. Complementation and substitution mutations in LapB and LpxC generally restored the phospholipid and LPS assembly defects for the pbgA mutants. During bacteremia, mice infected with the pbgA mutants survived and cleared the bacteria, while animals infected with wild-type salmonellae succumbed within 1 week. Remarkably, wild-type mice survived asymptomatically with pbgA-lpxC salmonellae in their livers and spleens for months, but Toll-like receptor 4-deficient animals succumbed to these infections within roughly 1 week. In summary, S. Typhimurium uses PbgA to influence LPS assembly during stress in order to survive, adapt, and proliferate within the host environment.

scholarly journals A Plasmid-Encoded FetMP-Fls Iron Uptake System Confers Selective Advantages to Salmonella enterica Serovar Typhimurium in Growth under Iron-Restricted Conditions and for Infection of Mammalian Host Cells

2020 ◽  
Vol 8 (5) ◽  
pp. 630
Author(s):  
Vanesa García ◽  
Ana Herrero-Fresno ◽  
Rosaura Rodicio ◽  
Alfonso Felipe-López ◽  
Ignacio Montero ◽  
...  
Keyword(s):  
Iron Content ◽  
Salmonella Enterica ◽  
Iron Uptake ◽  
Type Strain ◽  
Wild Type Strain ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Iron Acquisition ◽  
Clinical Strain ◽  
Wild Type ◽  
Serovar Typhimurium

The resistance plasmid pUO-StVR2, derived from virulence plasmid pSLT, is widespread in clinical isolates of Salmonella enterica serovar Typhimurium recovered in Spain and other European countries. pUO-StVR2 carries several genes encoding a FetMP-Fls system, which could be involved in iron uptake. We therefore analyzed S. Typhimurium LSP 146/02, a clinical strain selected as representative of the isolates carrying the plasmid, and an otherwise isogenic mutant lacking four genes (fetMP-flsDA) of the fetMP-fls region. Growth curves and determination of the intracellular iron content under iron-restricted conditions demonstrated that deletion of these genes impairs iron acquisition. Thus, under these conditions, the mutant grew significantly worse than the wild-type strain, its iron content was significantly lower, and it was outcompeted by the wild-type strain in competition assays. Importantly, the strain lacking the fetMP-flsDA genes was less invasive in cultured epithelial HeLa cells and replicated poorly upon infection of RAW264.7 macrophages. The genes were introduced into S. Typhimurium ATCC 14028, which lacks the FetMP-Fls system, and this resulted in increased growth under iron limitation as well as an increased ability to multiply inside macrophages. These findings indicate that the FetMP-Fls iron acquisition system exceeds the benefits conferred by the other high-affinity iron uptake systems carried by ATCC 14028 and LSP 146/02. We proposed that effective iron acquisition by this system in conjunction with antimicrobial resistance encoded from the same plasmid have greatly contributed to the epidemic success of S. Typhimurium isolates harboring pUO-StVR2.

scholarly journals The CorA Mg2+ Transporter Does Not Transport Fe2+

2004 ◽  
Vol 186 (22) ◽  
pp. 7653-7658 ◽  
Author(s):  
Krisztina M. Papp ◽  
Michael E. Maguire
Keyword(s):  
Salmonella Enterica ◽  
Iron Toxicity ◽  
Differential Sensitivity ◽  
Type Versus ◽  
Uptake System ◽  
Wild Type ◽  
Serovar Typhimurium ◽  
Transport Assay ◽  
The Relationship ◽  
Excess Fe

ABSTRACT corA encodes the constitutively expressed primary Mg2+ uptake system of most eubacteria and many archaea. Recently, a mutation in corA was reported to make Salmonella enterica serovar Typhimurium markedly resistant to Fe2+-mediated toxicity. Mechanistically, this was hypothesized to be from an ability of CorA to mediate the influx of Fe2+. Consequently, we directly examined Fe2+ transport and toxicity in wild-type versus corA cells. As determined by direct transport assay, CorA cannot transport Fe2+ and Fe2+ does not potently inhibit CorA transport of 63Ni2+. Mg2+ can, relatively weakly, inhibit Fe2+ uptake, but inhibition is not dependent on the presence of a functional corA allele. Although excess Fe2+ was slightly toxic to S. enterica serovar Typhimurium, we were unable to elicit a significant differential sensitivity in a wild-type versus a corA strain. We conclude that CorA does not transport Fe2+ and that the relationship, if any, between iron toxicity and corA is indirect.

scholarly journals sciS, an icmF Homolog in Salmonella enterica Serovar Typhimurium, Limits Intracellular Replication and Decreases Virulence

2005 ◽  
Vol 73 (7) ◽  
pp. 4338-4345 ◽  
Author(s):  
Duncan A. Parsons ◽  
Fred Heffron
Keyword(s):  
Legionella Pneumophila ◽  
Salmonella Enterica ◽  
Wild Type Strain ◽  
Salmonella Enterica Serovar Typhimurium ◽  
The Body ◽  
Wild Type ◽  
Serovar Typhimurium ◽  
Intracellular Multiplication ◽  
Late Stages ◽  
Made In

ABSTRACT Salmonella enterica serovar Typhimurium utilizes macrophages to disseminate from the intestine to deeper tissues within the body. While S. enterica serovar Typhimurium has been shown to kill its host macrophage, it can persist intracellularly beyond 18 h postinfection. To identify factors involved in late stages of infection, we screened a transposon library made in S. enterica serovar Typhimurium for the ability to persist in J774 macrophages at 24 h postinfection. Through this screen, we identified a gene, sciS, found to be homologous to icmF in Legionella pneumophila. icmF, which is required for intracellular multiplication, is conserved in several gram-negative pathogens, and its homolog appears to have been acquired horizontally in S. enterica serovar Typhimurium. We found that an sciS mutant displayed increased intracellular numbers in J774 macrophages when compared to the wild-type strain at 24 h postinfection. sciS was maximally transcribed at 27 h postinfection and is repressed by SsrB, an activator of genes required for promoting intracellular survival. Finally, we demonstrate that an sciS mutant is hypervirulent in mice when administered intragastrically. Taken together, these data indicate a role for SciS in controlling intracellular bacterial levels at later stages of infection and attenuating virulence in a murine host

scholarly journals Effect of Inactivation of degS on Salmonella enterica Serovar Typhimurium In Vitro and In Vivo

2005 ◽  
Vol 73 (1) ◽  
pp. 459-463 ◽  
Author(s):  
Gary Rowley ◽  
Andrew Stevenson ◽  
Jan Kormanec ◽  
Mark Roberts
Keyword(s):  
Sigma Factor ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Wild Type ◽  
Alternative Pathways ◽  
E Coli ◽  
Mammalian Tissues ◽  
Serovar Typhimurium

ABSTRACT The alternative sigma factor (RpoE σE) enables Salmonella enterica serovar Typhimurium to adapt to stressful conditions, such as oxidative stress, nutrient deprivation, and growth in mammalian tissues. Infection of mice by Salmonella serovar Typhimurium also requires σE. In Escherichia coli, activation of the σE pathway is dependent on proteolysis of the anti-sigma factor RseA and is initiated by DegS. DegS is also important in order for E. coli to cause extraintestinal infection in mice. We constructed a degS mutant of the serovar Typhimurium strain SL1344 and compared its behavior in vitro and in vivo with those of its wild-type (WT) parent and an isogenic rpoE mutant. Unlike E. coli degS strains, the Salmonella serovar Typhimurium degS strain grew as well as the WT strain at 42°C. The degS mutant survived very poorly in murine macrophages in vitro and was highly attenuated compared with the WT strain for both the oral and parenteral routes of infection in mice. However, the degS mutant was not as attenuated as the serovar Typhimurium rpoE mutant: 100- to 1,000-fold more degS bacteria than rpoE bacteria were present in the livers and spleens of mice 24 h after intraperitoneal challenge. In most assays, the rpoE mutant was more severely affected than the degS mutant and a σE-dependent reporter gene was more active in the degS mutant than the rpoE strain. These findings indicate that degS is important for activation of the σE pathway in serovar Typhimurium but that alternative pathways for σE activation probably exist.

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