scholarly journals Oral Pathogen Porphyromonas gingivalis Can Escape Phagocytosis of Mammalian Macrophages

2020 ◽  
Vol 8 (9) ◽  
pp. 1432
Author(s):  
Erik R. Werheim ◽  
Kevin G. Senior ◽  
Carly A. Shaffer ◽  
Giancarlo A. Cuadra
Keyword(s):  
Escherichia Coli ◽  
Porphyromonas Gingivalis ◽  
Microbial Pathogens ◽  
Intracellular Bacteria ◽  
Raw 264.7 ◽  
Phagocytic Cells ◽  
Oral Pathogen ◽  
Human Macrophages ◽  
Macrophage Phagocytosis ◽  
Mouse Macrophages

Macrophages are phagocytic cells that play a key role in host immune response and clearance of microbial pathogens. Porphyromonas gingivalis is an oral pathogen associated with the development of periodontitis. Escape from macrophage phagocytosis was tested by infecting THP-1-derived human macrophages and RAW 264.7 mouse macrophages with strains of P. gingivalis W83 and 33277 as well as Streptococcus gordonii DL1 and Escherichia coli OP50 at MOI = 100. CFU counts for all intracellular bacteria were determined. Then, infected macrophages were cultured in media without antibiotics to allow for escape and escaping bacteria were quantified by CFU counting. P. gingivalis W83 displayed over 60% of the bacterial escape from the total amount of intracellular CFUs, significantly higher compared to all other bacteria strains. In addition, bacterial escape and re-entry were also tested and P. gingivalis W83, once again, showed the highest numbers of CFUs able to exit and re-enter macrophages. Lastly, the function of the PG0717 gene of P. gingivalis W83 was tested on escape but found not related to this activity. Altogether, our results suggest that P. gingivalis W83 is able to significantly avoid macrophage phagocytosis. We propose this ability is likely linked to the chronic nature of periodontitis.

scholarly journals The pH 6 Antigen Is an Antiphagocytic Factor Produced by Yersinia pestis Independent of Yersinia Outer Proteins and Capsule Antigen

2004 ◽  
Vol 72 (12) ◽  
pp. 7212-7219 ◽  
Author(s):  
Xiao-Zhe Huang ◽  
Luther E. Lindler
Keyword(s):  
Escherichia Coli ◽  
Yersinia Pestis ◽  
Intracellular Bacteria ◽  
Mouse Macrophage ◽  
Host Cell Line ◽  
E Coli ◽  
Significant Difference ◽  
Mouse Macrophages ◽  
Isogenic Strains ◽  
Raw264.7 Macrophage

ABSTRACT The pH 6 antigen (pH 6 Ag; PsaA) of Yersinia pestis has been shown to be a virulence factor. In this study, we set out to investigate the possible function of Y. pestis PsaA in a host cell line, RAW264.7 mouse macrophages, in order to better understand the role it might play in virulence. Y. pestis KIM5 derivatives with and without the pCD1 plasmid and their psaA isogenic counterparts and Escherichia coli HB101 and DΗ5α carrying a psaA clone or a vector control were used for macrophage infections. Macrophage-related bacteria and gentamicin-resistant intracellular bacteria generated from plate counting and direct microscopic examinations were used to evaluate these RAW264.7 macrophage infections. Y. pestis psaA isogenic strains did not show any significant difference in their abilities to associate with or bind to mouse macrophage cells. However, expression of psaA appeared to significantly reduce phagocytosis of both Y. pestis and E. coli by mouse macrophages (P < 0.05). Furthermore, we found that complementation of psaA mutant Y. pestis strains could completely restore the ability of the bacteria to resist phagocytosis. Fluorescence microscopy following differential labeling of intracellular and extracellular Y. pestis revealed that significantly lower numbers of psaA-expressing bacteria were located inside the macrophages. Enhanced phagocytosis resistance was specific for bacteria expressing psaA and did not influence the ability of the macrophages to engulf other bacteria. Our data demonstrate that Y. pestis pH 6 Ag does not enhance adhesion to mouse macrophages but rather promotes resistance to phagocytosis.

scholarly journals Connective tissue proteins and phagocytic cell function. Laminin enhances complement and Fc-mediated phagocytosis by cultured human macrophages.

1985 ◽  
Vol 161 (5) ◽  
pp. 912-923 ◽  
Author(s):  
J F Bohnsack ◽  
H K Kleinman ◽  
T Takahashi ◽  
J J O'Shea ◽  
E J Brown
Keyword(s):  
Cell Function ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Basement Membranes ◽  
Enzyme Linked Immunosorbent Assay ◽  
Phagocytic Cell ◽  
Phagocytic Cells ◽  
Enhancing Effect ◽  
Human Macrophages ◽  
Macrophage Phagocytosis

Brief exposure of culture-derived human macrophages to laminin, a glycoprotein component of all mammalian basement membranes that has a molecular weight of 1,000,000, led to enhancement of subsequent macrophage phagocytosis of EAC4b, EAC3bi, and EAIgG (sheep erythrocytes sensitized with IgG anti-Forssman antibody). This effect on macrophage phagocytosis occurred with both substrate-adherent and fluid phase laminin. Preincubation of macrophages, but not of EAC4b, with laminin led to augmentation of phagocytosis, suggesting that interaction with the phagocytic cell, but not with the opsonized particle, was required for laminin's effect. Laminin-stimulated phagocytosis of EAC4b was blocked entirely by a monoclonal antibody to CR1. Direct comparison of the phagocytic ability of macrophages adherent to laminin- and fibronectin-coated glass slides showed that fibronectin had a somewhat greater enhancing effect on phagocytosis. Nonetheless, the phagocytosis-enhancing effect of laminin was not due to contamination of the purified laminin preparation by fibronectin, since the laminin preparation was free of fibronectin, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and enzyme-linked immunosorbent assay; in addition, laminin-enhanced phagocytosis was decreased in the presence of laminin-specific antibodies. Laminin inhibited macrophage adherence and spreading, but selection of a laminin-binding macrophage subpopulation could not account for the laminin-induced increases in phagocytosis. We hypothesize that interaction with extracellular matrix proteins may represent an important activation stimulus both to the macrophages normally present in the extravascular compartment and to the phagocytic cells that have emigrated from the blood-stream into areas of inflammation.

scholarly journals An infection-induced RhoB-Beclin 1-Hsp90 complex enhances clearance of uropathogenic Escherichia coli

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chunhui Miao ◽  
Mingyu Yu ◽  
Geng Pei ◽  
Zhenyi Ma ◽  
Lisong Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Treatment Strategies ◽  
Uropathogenic Escherichia Coli ◽  
Beclin 1 ◽  
Host Cells ◽  
Infection Model ◽  
Intracellular Bacteria ◽  
Bladder Epithelium ◽  
Binding Residue

AbstractHost cells use several anti-bacterial pathways to defend against pathogens. Here, using a uropathogenic Escherichia coli (UPEC) infection model, we demonstrate that bacterial infection upregulates RhoB, which subsequently promotes intracellular bacteria clearance by inducing LC3 lipidation and autophagosome formation. RhoB binds with Beclin 1 through its residues at 118 to 140 and the Beclin 1 CCD domain, with RhoB Arg133 being the key binding residue. Binding of RhoB to Beclin 1 enhances the Hsp90-Beclin 1 interaction, preventing Beclin 1 degradation. RhoB also directly interacts with Hsp90, maintaining RhoB levels. UPEC infections increase RhoB, Beclin 1 and LC3 levels in bladder epithelium in vivo, whereas Beclin 1 and LC3 levels as well as UPEC clearance are substantially reduced in RhoB+/− and RhoB−/− mice upon infection. We conclude that when stimulated by UPEC infections, host cells promote UPEC clearance through the RhoB-Beclin 1-HSP90 complex, indicating RhoB may be a useful target when developing UPEC treatment strategies.

scholarly journals The novel Dbl homology/BAR domain protein, MsgA, of Talaromyces marneffei regulates yeast morphogenesis during growth inside host cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Harshini Weerasinghe ◽  
Hayley E. Bugeja ◽  
Alex Andrianopoulos
Keyword(s):  
Pathogenic Fungi ◽  
Host Cells ◽  
Microbial Pathogens ◽  
Mammalian Host ◽  
Host Immune System ◽  
Nucleotide Exchange ◽  
Phagocytic Cells ◽  
Macrophage Infection ◽  
Bar Domain ◽  
Talaromyces Marneffei

AbstractMicrobial pathogens have evolved many strategies to evade recognition by the host immune system, including the use of phagocytic cells as a niche within which to proliferate. Dimorphic pathogenic fungi employ an induced morphogenetic transition, switching from multicellular hyphae to unicellular yeast that are more compatible with intracellular growth. A switch to mammalian host body temperature (37 °C) is a key trigger for the dimorphic switch. This study describes a novel gene, msgA, from the dimorphic fungal pathogen Talaromyces marneffei that controls cell morphology in response to host cues rather than temperature. The msgA gene is upregulated during murine macrophage infection, and deletion results in aberrant yeast morphology solely during growth inside macrophages. MsgA contains a Dbl homology domain, and a Bin, Amphiphysin, Rvs (BAR) domain instead of a Plekstrin homology domain typically associated with guanine nucleotide exchange factors (GEFs). The BAR domain is crucial in maintaining yeast morphology and cellular localisation during infection. The data suggests that MsgA does not act as a canonical GEF during macrophage infection and identifies a temperature independent pathway in T. marneffei that controls intracellular yeast morphogenesis.

scholarly journals The PTS Components in Klebsiella pneumoniae Affect Bacterial Capsular Polysaccharide Production and Macrophage Phagocytosis Resistance

2021 ◽  
Vol 9 (2) ◽  
pp. 335
Author(s):  
Novaria Sari Dewi Panjaitan ◽  
Yu-Tze Horng ◽  
Chih-Ching Chien ◽  
Hung-Chi Yang ◽  
Ren-In You ◽  
...  
Keyword(s):  
Survival Rate ◽  
Klebsiella Pneumoniae ◽  
Laser Scanning ◽  
Bacterial Resistance ◽  
Capsular Polysaccharide ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Intracellular Bacteria ◽  
Wild Type ◽  
Macrophage Phagocytosis

Capsular polysaccharide (CPS) is a crucial virulence factor for Klebsiella pneumoniae infection. We demonstrated an association of CPS production with two phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTSs). Deficiency of crr, encoding enzyme IIA of PTS, in K. pneumoniae enhanced the transcriptional activities of galF, wzi and gnd, which are in the cps gene cluster, leading to high CPS production. A crr mutant exhibited a higher survival rate in 1% hydrogen peroxide than the wild-type. The crr mutant showed less sensitivity to engulfment by macrophage (RAW 264.7) than the wild-type by observing the intracellular bacteria using confocal laser scanning microscopy (CLSM) and by calculating the colony-forming units (CFU) of intracellular bacteria. After long-term incubation, the survival rate of the intracellular crr mutant was higher than that of the wild-type. Deficiency of crr enhanced the transcriptional activities of etcABC which encodes another putative enzyme II complex of a PTS. Deletion of etcABC in the crr mutant reduced CPS production and the transcriptional activities of galF compared to those of the crr mutant. These results indicated that one PTS component, Crr, represses CPS production by repressing another PTS component, EtcABC, in K. pneumoniae. In addition, PTS plays a role in bacterial resistance to macrophage phagocytosis.

scholarly journals Inhibition of Escherichia coli O157:H7 and Salmonella enterica Isolates on Spinach Leaf Surfaces Using Eugenol-Loaded Surfactant Micelles

Foods ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 575
Author(s):  
Songsirin Ruengvisesh ◽  
Chris R. Kerth ◽  
T. Matthew Taylor
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Limit Of Detection ◽  
Sodium Dodecyl ◽  
Microbial Pathogens ◽  
Escherichia Coli O157 ◽  
Human Pathogens ◽  
Surfactant Micelles ◽  
Leaf Surfaces ◽  
Spinach Leaf

Spinach and other leafy green vegetables have been linked to foodborne disease outbreaks of Escherichia coli O157:H7 and Salmonella enterica around the globe. In this study, the antimicrobial activities of surfactant micelles formed from the anionic surfactant sodium dodecyl sulfate (SDS), SDS micelle-loaded eugenol (1.0% eugenol), 1.0% free eugenol, 200 ppm free chlorine, and sterile water were tested against the human pathogens E. coli O157:H7 and Salmonella Saintpaul, and naturally occurring microorganisms, on spinach leaf surfaces during storage at 5 °C over 10 days. Spinach samples were immersed in antimicrobial treatment solution for 2.0 min at 25 °C, after which treatment solutions were drained off and samples were either subjected to analysis or prepared for refrigerated storage. Whereas empty SDS micelles produced moderate reductions in counts of both pathogens (2.1–3.2 log10 CFU/cm2), free and micelle-entrapped eugenol treatments reduced pathogens by >5.0 log10 CFU/cm2 to below the limit of detection (<0.5 log10 CFU/cm2). Micelle-loaded eugenol produced the greatest numerical reductions in naturally contaminating aerobic bacteria, Enterobacteriaceae, and fungi, though these reductions did not differ statistically from reductions achieved by un-encapsulated eugenol and 200 ppm chlorine. Micelles-loaded eugenol could be used as a novel antimicrobial technology to decontaminate fresh spinach from microbial pathogens.

scholarly journals Saccharomyces boulardii Preserves the Barrier Function and Modulates the Signal Transduction Pathway Induced in Enteropathogenic Escherichia coli-Infected T84 Cells

2000 ◽  
Vol 68 (10) ◽  
pp. 5998-6004 ◽  
Author(s):  
Dorota Czerucka ◽  
Stephanie Dahan ◽  
Baharia Mograbi ◽  
Bernard Rossi ◽  
Patrick Rampal
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Signal Transduction Pathway ◽  
Specific Inhibitor ◽  
Saccharomyces Boulardii ◽  
Intracellular Bacteria ◽  
T84 Cells ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Map Kinase Pathway

ABSTRACT Use of the nonpathogenic yeast Saccharomyces boulardiiin the treatment of infectious diarrhea has attracted growing interest. The present study designed to investigate the effect of this yeast on enteropathogenic Escherichia coli (EPEC)-associated disease demonstrates that S. boulardii abrogated the alterations induced by an EPEC strain on transepithelial resistance, [3H]inulin flux, and ZO-1 distribution in T84 cells. Moreover, EPEC-mediated apoptosis of epithelial cells was delayed in the presence of S. boulardii. The yeast did not modify the number of adherent bacteria but lowered by 50% the number of intracellular bacteria. Infection by EPEC induced tyrosine phosphorylation of several proteins in T84 cells, including p46 and p52 SHC isoforms, that was attenuated in the presence of S. boulardii. Similarly, EPEC-induced activation of the ERK1/2 mitogen-activated protein (MAP) kinase pathway was diminished in the presence of the yeast. Interestingly, inhibition of the ERK1/2 pathway with the specific inhibitor PD 98059 decreased EPEC internalization, suggesting that modulation of the ERK1/2 MAP pathway might account for the lowering of the number of intracellular bacteria observed in the presence of S. boulardii. Altogether, this study demonstrated that S. boulardii exerts a protective effect on epithelial cells after EPEC adhesion by modulating the signaling pathway induced by bacterial infection.

The Effects of Wood Dusts on the Redox Status and Cell Death in Mouse Macrophages (Raw 264.7) and Human Leukocytes in Vitro

2003 ◽  
Vol 66 (13) ◽  
pp. 1221-1235 ◽  
Author(s):  
J. Naarala ◽  
J.-P. Kasanen ◽  
P. Pasanen ◽  
A.-L. Pasanen ◽  
A. Liimatainen ◽  
...  
Keyword(s):  
Cell Death ◽  
Redox Status ◽  
Raw 264.7 ◽  
Human Leukocytes ◽  
Mouse Macrophages

Mannose-Binding Activity of Escherichia coli: a Determinant of Attachment and Ingestion of the Bacteria by Macrophages

1980 ◽  
Vol 29 (2) ◽  
pp. 417-424
Author(s):  
Zvi Bar-Shavit ◽  
Rachel Goldman ◽  
Itzhak Ofek ◽  
Nathan Sharon ◽  
David Mirelman
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Pathogenic Bacteria ◽  
Binding Activity ◽  
Exponential Phase ◽  
Restrictive Temperature ◽  
Filamentous Bacteria ◽  
Phagocytic Cells ◽  
E Coli ◽  
Mannose Binding

Recently, it was suggested that a mannose-specific lectin on the bacterial cell surface is responsible for the recognition by phagocytic cells of certain nonopsonized Escherichia coli strains. In this study we assessed the interaction of two strains of E. coli at different phases of growth with a monolayer of mouse peritoneal macrophages and developed a direct method with [ 14 C]mannan to quantitate the bacterial mannose-binding activity. Normal-sized bacteria were obtained from logarithmic and stationary phases of growth. Nonseptated filamentous cells were formed by growing the organisms in the presence of cephalexin or at a restrictive temperature. Attachment to macrophages of all bacterial forms was inhibited by methyl α- d -mannoside and mannan but not by other sugars tested. The attachment of stationary phase and filamentous bacteria to macrophages, as well as their mannose-binding activity, was similar, whereas in the exponential-phase bacteria they were markedly reduced. The results show a linear relation between the two parameters ( R = 0.98, P < 0.001). The internalization of the filamentous cells attached to macrophages during 45 min of incubation was much less efficient (20%) compared to that of exponential-phase, stationary-phase, or antibody-coated filamentous bacteria (90%). The results indicate that the mannose-binding activity of E. coli determines the recognition of the organisms by phagocytes. They further suggest that administration of β-lactam antibiotics may impair elimination of certain pathogenic bacteria by inducing the formation of filaments which are inefficiently internalized by the host's phagocytic cells.

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