scholarly journals Listeriolysin O: from bazooka to Swiss army knife

2017 ◽  
Vol 372 (1726) ◽  
pp. 20160222 ◽  
Author(s):  
Suzanne E. Osborne ◽  
John H. Brumell
Keyword(s):  
Systemic Disease ◽  
Membrane Damage ◽  
Host Cells ◽  
Listeriolysin O ◽  
Tissue Destruction ◽  
Membrane Repair ◽  
Membrane Pores ◽  
Bacterial Dissemination ◽  
Versatile Tool ◽  
Cell Spread

Listeria monocytogenes ( Lm ) is a Gram-positive facultative intracellular pathogen. Infections in humans can lead to listeriosis, a systemic disease with a high mortality rate. One important mechanism of Lm dissemination involves cell-to-cell spread after bacteria have entered the cytosol of host cells. Listeriolysin O (LLO; encoded by the hly gene) is a virulence factor present in Lm that plays a central role in the cell-to-cell spread process. LLO is a member of the cholesterol-dependent cytolysin (CDC) family of toxins that were initially thought to promote disease largely by inducing cell death and tissue destruction—essentially acting like a ‘bazooka’. This view was supported by structural studies showing CDCs can form large pores in membranes. However, it is now appreciated that LLO has many subtle activities during Lm infection of host cells, and many of these likely do not involve large pores, but rather small membrane perforations. It is also appreciated that membrane repair pathways of host cells play a major role in limiting membrane damage by LLO and other toxins. LLO is now thought to represent a ‘Swiss army knife’, a versatile tool that allows Lm to induce many membrane alterations and cellular responses that promote bacterial dissemination during infection. This article is part of the themed issue ‘Membrane pores: from structure and assembly, to medicine and technology’.

scholarly journals Compartmentalization of the Broad-Range Phospholipase C Activity to the Spreading Vacuole Is Critical for Listeria monocytogenes Virulence

2006 ◽  
Vol 75 (1) ◽  
pp. 44-51 ◽  
Author(s):  
P. S. Marie Yeung ◽  
Yoojin Na ◽  
Amanda J. Kreuder ◽  
Hélène Marquis
Keyword(s):  
Listeria Monocytogenes ◽  
Phospholipase C ◽  
Membrane Damage ◽  
Bacterial Pathogen ◽  
Host Cells ◽  
Virulence Attenuation ◽  
Infected Cells ◽  
Host Cell Membranes ◽  
Cell Spread

ABSTRACT Listeria monocytogenes is a bacterial pathogen that multiplies in the cytosol of host cells and spreads directly from cell to cell by using an actin-based mechanism of motility. The broad-range phospholipase C (PC-PLC) of L. monocytogenes contributes to bacterial escape from vacuoles formed upon cell-to-cell spread. PC-PLC is made as an inactive proenzyme whose activation requires cleavage of an N-terminal propeptide. During infection, PC-PLC is activated specifically in acidified vacuoles. To assess the importance of compartmentalizing PC-PLC activity during infection, we created a mutant that makes constitutively active PC-PLC (the plcBΔpro mutant). Results from intracellular growth and cell-to-cell spread assays showed that the plcBΔpro mutant was sensitive to gentamicin, suggesting that unregulated PC-PLC activity causes damage to host cell membranes. This was confirmed by the observation of a twofold increase in staining of live infected cells by a non-membrane-permeant DNA fluorescent dye. However, membrane damage was not sufficient to cause cell lysis and was dependent on bacterial cell-to-cell spread, suggesting that damage was localized to bacterium-containing filopodia. Using an in vivo competitive infection assay, we observed that the plcBΔpro mutant was outcompeted up to 200-fold by the wild-type strain in BALB/c mice. Virulence attenuation was greater when mice were infected orally than when they were infected intravenously, presumably because the plcBΔpro mutant was initially outcompeted in the intestines, reducing the number of mutant bacteria reaching the liver and spleen. Together, these results emphasize the importance for L. monocytogenes virulence of compartmentalizing the activity of PC-PLC during infection.

scholarly journals The Posttranslocation Chaperone PrsA2 Contributes to Multiple Facets of Listeria monocytogenes Pathogenesis

2009 ◽  
Vol 77 (7) ◽  
pp. 2612-2623 ◽  
Author(s):  
Francis Alonzo ◽  
Gary C. Port ◽  
Min Cao ◽  
Nancy E. Freitag
Keyword(s):  
Listeria Monocytogenes ◽  
Gene Product ◽  
Bacterial Pathogen ◽  
Virulence Gene ◽  
Host Cells ◽  
Listeriolysin O ◽  
Virulence Gene Expression ◽  
High Concentrations ◽  
Host Infection ◽  
Cell Spread

ABSTRACT Listeria monocytogenes is an intracellular bacterial pathogen whose virulence depends on the regulated expression of numerous secreted bacterial factors. As for other gram-positive bacteria, many proteins secreted by L. monocytogenes are translocated across the bacterial membrane in an unfolded state to the compartment existing between the membrane and the cell wall. This compartment presents a challenging environment for protein folding due to its high density of negative charge, high concentrations of cations, and low pH. We recently identified PrsA2 as a gene product required for L. monocytogenes virulence. PrsA2 was identified based on its increased secretion by strains containing a mutationally activated form of prfA, the key regulator of L. monocytogenes virulence gene expression. The prsA2 gene product is one of at least two predicted peptidyl-prolyl cis/trans-isomerases encoded by L. monocytogenes; these proteins function as posttranslocation protein chaperones and/or foldases. In this study, we demonstrate that PrsA2 plays a unique and important role in L. monocytogenes pathogenesis by promoting the activity and stability of at least two critical secreted virulence factors: listeriolysin O (LLO) and a broad-specificity phospholipase. Loss of PrsA2 activity severely attenuated virulence in mice and impaired bacterial cell-to-cell spread in host cells. In contrast, mutants lacking prsA1 resembled wild-type bacteria with respect to intracellular growth and cell-to-cell spread as well as virulence in mice. PrsA2 is thus distinct from PrsA1 in its unique requirement for the stability and full activity of L. monocytogenes-secreted factors that contribute to host infection.

scholarly journals Characterization of Listeria monocytogenes Expressing Anthrolysin O and Phosphatidylinositol-Specific Phospholipase C from Bacillus anthracis

2005 ◽  
Vol 73 (10) ◽  
pp. 6639-6646 ◽  
Author(s):  
Zhengyu Wei ◽  
Pamela Schnupf ◽  
Mathilde A. Poussin ◽  
Lauren A. Zenewicz ◽  
Hao Shen ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Bacillus Anthracis ◽  
Host Cell ◽  
Phospholipase C ◽  
Host Cells ◽  
Listeriolysin O ◽  
Intracellular Growth ◽  
Cell Cytosol ◽  
Anthrolysin O ◽  
Cell Spread

ABSTRACT Two virulence factors of Listeria monocytogenes, listeriolysin O (LLO) and phosphatidylinositol-specific phospholipase C (PI-PLC), mediate escape of this pathogen from the phagocytic vacuole of macrophages, thereby allowing the bacterium access to the host cell cytosol for growth and spread to neighboring cells. We characterized their orthologs from Bacillus anthracis by expressing them in L. monocytogenes and characterizing their contribution to bacterial intracellular growth and cell-to-cell spread. We generated a series of L. monocytogenes strains expressing B. anthracis anthrolysin O (ALO) and PI-PLC in place of LLO and L. monocytogenes PI-PLC, respectively. We found that ALO was active at both acidic and neutral pH and could functionally replace LLO in mediating escape from a primary vacuole; however, ALO exerted a toxic effect on the host cell by damaging the plasma membrane. B. anthracis PI-PLC, unlike the L. monocytogenes ortholog, had high activity on glycosylphosphatidylinositol-anchored proteins. L. monocytogenes expressing B. anthracis PI-PLC showed significantly decreased efficiencies of escape from a phagosome and in cell-to-cell spread. We further compared the level of cytotoxicity to host cells by using mutant strains expressing ALO in combination either with L. monocytogenes PI-PLC or with B. anthracis PI-PLC. The results demonstrated that the mutant strain expressing the combination of ALO and B. anthracis PI-PLC caused less damage to host cells than the strain expressing ALO and L. monocytogenes PI-PLC. The present study indicates that LLO and L. monocytogenes PI-PLC has adapted for L. monocytogenes intracellular growth and virulence and suggests that ALO and B. anthracis PI-PLC may have a role in B. anthracis pathogenesis.

scholarly journals Host cell perforation by listeriolysin O (LLO) activates a Ca2+-dependent cPKC/Rac1/Arp2/3 signaling pathway that promotesListeria monocytogenesinternalization independently of membrane resealing

2018 ◽  
Vol 29 (3) ◽  
pp. 270-284 ◽  
Author(s):  
Jonathan G. T. Lam ◽  
Stephen Vadia ◽  
Sarika Pathak-Sharma ◽  
Eric McLaughlin ◽  
Xiaoli Zhang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Host Cell ◽  
Signaling Pathway ◽  
Membrane Damage ◽  
Host Cells ◽  
Listeriolysin O ◽  
Plasma Membrane Damage ◽  
Host Plasma Membrane ◽  
Membrane Resealing

Pathogen-induced host plasma membrane damage is a recently recognized mechanism used by pathogens to promote their entry into host cells. We identified key transducers activated upon host cell perforation by the pore-forming toxin LLO to promote Listeria entry. This pathway is distinct from the pathway that reseals the toxin-perforated cell.

scholarly journals Nexus between COVID-19 and periodontal disease

2021 ◽  
Vol 49 (3) ◽  
pp. 030006052110026
Author(s):  
Kanchana Sukumar ◽  
Anupama Tadepalli
Keyword(s):  
Periodontal Disease ◽  
Host Cells ◽  
Multifactorial Disease ◽  
Tissue Destruction ◽  
The Past ◽  
Appropriate Care ◽  
Bacterial Stimulation ◽  
Plaque Control ◽  
Disease Understanding ◽  
Pro Inflammatory Cytokines

Over the past several decades, studies have demonstrated the existence of bi-directional relationships between periodontal disease and systemic conditions. Periodontitis is a polymicrobial and multifactorial disease involving both host and environmental factors. Tissue destruction is primarily associated with hyperresponsiveness of the host resulting in release of inflammatory mediators. Pro-inflammatory cytokines play a major role in bacterial stimulation and tissue destruction. In addition, these cytokines are thought to underlie the associations between periodontitis and systemic conditions. Current research suggests that increased release of cytokines from host cells, referred to as the cytokine storm, is associated with disease progression in patients with coronavirus disease 2019 (COVID-19). An intersection between periodontitis and pulmonary disease is biologically plausible. Hence, we reviewed the evidence linking COVID-19, cytokines, and periodontal disease. Plaque control is essential to prevent exchange of bacteria between the mouth and the lungs, reducing the risk of lung disease. Understanding these associations may help identify individuals at high risk and deliver appropriate care at early stages.

scholarly journals The Burkholderia pseudomallei intracellular ‘TRANSITome’

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yun Heacock-Kang ◽  
Ian A. McMillan ◽  
Michael H. Norris ◽  
Zhenxin Sun ◽  
Jan Zarzycki-Siek ◽  
...  
Keyword(s):  
Gene Expression ◽  
Population Dynamics ◽  
Burkholderia Pseudomallei ◽  
Host Cells ◽  
Hypothetical Proteins ◽  
Membrane Protrusion ◽  
Complex Environments ◽  
Cell Infection ◽  
Prokaryotic Cell ◽  
Cell Spread

AbstractProkaryotic cell transcriptomics has been limited to mixed or sub-population dynamics and individual cells within heterogeneous populations, which has hampered further understanding of spatiotemporal and stage-specific processes of prokaryotic cells within complex environments. Here we develop a ‘TRANSITomic’ approach to profile transcriptomes of single Burkholderia pseudomallei cells as they transit through host cell infection at defined stages, yielding pathophysiological insights. We find that B. pseudomallei transits through host cells during infection in three observable stages: vacuole entry; cytoplasmic escape and replication; and membrane protrusion, promoting cell-to-cell spread. The B. pseudomallei ‘TRANSITome’ reveals dynamic gene-expression flux during transit in host cells and identifies genes that are required for pathogenesis. We find several hypothetical proteins and assign them to virulence mechanisms, including attachment, cytoskeletal modulation, and autophagy evasion. The B. pseudomallei ‘TRANSITome’ provides prokaryotic single-cell transcriptomics information enabling high-resolution understanding of host-pathogen interactions.

scholarly journals The Listeria monocytogenes hemolysin has an acidic pH optimum to compartmentalize activity and prevent damage to infected host cells

2002 ◽  
Vol 156 (6) ◽  
pp. 1029-1038 ◽  
Author(s):  
Ian J. Glomski ◽  
Margaret M. Gedde ◽  
Albert W. Tsang ◽  
Joel A. Swanson ◽  
Daniel A. Portnoy
Keyword(s):  
Listeria Monocytogenes ◽  
Bacterial Pathogen ◽  
Cytolytic Activity ◽  
Host Cells ◽  
Adaptive Mutation ◽  
Acidic Ph ◽  
Listeriolysin O ◽  
Lysosomal Hydrolases ◽  
Ph Optimum ◽  
Neutral Ph

Listeria monocytogenes is a facultative intracellular bacterial pathogen that escapes from a phagosome and grows in the host cell cytosol. The pore-forming cholesterol-dependent cytolysin, listeriolysin O (LLO), mediates bacterial escape from vesicles and is ∼10-fold more active at an acidic than neutral pH. By swapping dissimilar residues from a pH-insensitive orthologue, perfringolysin O (PFO), we identified leucine 461 as unique to pathogenic Listeria and responsible for the acidic pH optimum of LLO. Conversion of leucine 461 to the threonine present in PFO increased the hemolytic activity of LLO almost 10-fold at a neutral pH. L. monocytogenes synthesizing LLO L461T, expressed from its endogenous site on the bacterial chromosome, resulted in a 100-fold virulence defect in the mouse listeriosis model. These bacteria escaped from acidic phagosomes and initially grew normally in cells and spread cell to cell, but prematurely permeabilized the host membrane and killed the cell. These data show that the acidic pH optimum of LLO results from an adaptive mutation that acts to limit cytolytic activity to acidic vesicles and prevent damage in the host cytosol, a strategy also used by host cells to compartmentalize lysosomal hydrolases.

scholarly journals Plasma membrane damage caused by listeriolysin O is not repaired through endocytosis of the membrane pore

Biology Open ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. bio035287 ◽  
Author(s):  
Lars Nygård Skalman ◽  
Mikkel R. Holst ◽  
Elin Larsson ◽  
Richard Lundmark
Keyword(s):  
Plasma Membrane ◽  
Membrane Damage ◽  
Listeriolysin O ◽  
Membrane Pore ◽  
Plasma Membrane Damage

scholarly journals Efficient Killing of Multidrug-Resistant Intracellular Bacteria by AIEgens in Vivo

2020 ◽  
Author(s):  
Ying Li ◽  
Fei Liu ◽  
Jiangjiang Zhang ◽  
Xiaoye Liu ◽  
Peihong Xiao ◽  
...  
Keyword(s):  
Membrane Damage ◽  
Multidrug Resistant ◽  
Host Cells ◽  
Comparable Efficacy ◽  
Intracellular Bacteria ◽  
New Agents ◽  
Immune Clearance ◽  
Infected Cells ◽  
Dose Levels

<p><a>Bacteria infected cells acting as “Trojan horses” not only protect bacteria from antibiotic therapies and immune clearance, but also increase the dissemination of pathogens from the initial sites of infection. Antibiotics are hard and insufficient to treat such hidden intracellular bacteria, especially the multidrug</a>-resistant (MDR) bacteria. Herein, aggregation-induced emission luminogens (AIEgens) such as TBPs showed potent broad-spectrum bactericidal activity against both <a></a><a>extracellular and intracellular</a> Gram-positive pathogens at low-dose levels. TBPs triggered reactive oxygen species (ROS)-mediated membrane damage to kill bacteria, regardless of light irradiation. Additionally, such AIEgens activated mitochondria dependent autophagy to eliminate intracellular bacteria in host cells. Compared to the routinely used vancomycin in clinics, TBPs showed comparable efficacy against methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) <i>in vivo</i>. Our studies demonstrate that AIEgens are promising new agents for the treatment of MDR bacteria associated infections.</p>

scholarly journals Inhibition of the master regulator of Listeria monocytogenes virulence enables bacterial clearance from spacious replication vacuoles in infected macrophages

2022 ◽  
Vol 18 (1) ◽  
pp. e1010166
Author(s):  
Thao Thanh Tran ◽  
Carmen D. Mathmann ◽  
Marcela Gatica-Andrades ◽  
Rachel F. Rollo ◽  
Melanie Oelker ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Host Cells ◽  
Intracellular Bacteria ◽  
Bacterial Clearance ◽  
Lysosomal Degradation ◽  
Cell Cytoplasm ◽  
Host Cell Cytoplasm ◽  
Molecule Inhibitor ◽  
Bacterial Replication ◽  
Cell Spread

A hallmark of Listeria (L.) monocytogenes pathogenesis is bacterial escape from maturing entry vacuoles, which is required for rapid bacterial replication in the host cell cytoplasm and cell-to-cell spread. The bacterial transcriptional activator PrfA controls expression of key virulence factors that enable exploitation of this intracellular niche. The transcriptional activity of PrfA within infected host cells is controlled by allosteric coactivation. Inhibitory occupation of the coactivator site has been shown to impair PrfA functions, but consequences of PrfA inhibition for L. monocytogenes infection and pathogenesis are unknown. Here we report the crystal structure of PrfA with a small molecule inhibitor occupying the coactivator site at 2.0 Å resolution. Using molecular imaging and infection studies in macrophages, we demonstrate that PrfA inhibition prevents the vacuolar escape of L. monocytogenes and enables extensive bacterial replication inside spacious vacuoles. In contrast to previously described spacious Listeria-containing vacuoles, which have been implicated in supporting chronic infection, PrfA inhibition facilitated progressive clearance of intracellular L. monocytogenes from spacious vacuoles through lysosomal degradation. Thus, inhibitory occupation of the PrfA coactivator site facilitates formation of a transient intravacuolar L. monocytogenes replication niche that licenses macrophages to effectively eliminate intracellular bacteria. Our findings encourage further exploration of PrfA as a potential target for antimicrobials and highlight that intra-vacuolar residence of L. monocytogenes in macrophages is not inevitably tied to bacterial persistence.

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