scholarly journals Filifactor alocis Promotes Neutrophil Degranulation and Chemotactic Activity

2016 ◽  
Vol 84 (12) ◽  
pp. 3423-3433 ◽  
Author(s):  
Cortney L. Armstrong ◽  
Irina Miralda ◽  
Adam C. Neff ◽  
Shifu Tian ◽  
Aruna Vashishta ◽  
...  
Keyword(s):  
P38 Mapk ◽  
Periodontal Pocket ◽  
Human Neutrophils ◽  
Neutrophil Chemotaxis ◽  
Granule Exocytosis ◽  
Content Type ◽  
Innate Defense ◽  
Random Migration ◽  
Neutrophil Degranulation ◽  
Filifactor Alocis

Filifactor alocis is a recently recognized periodontal pathogen; however, little is known regarding its interactions with the immune system. As the first-responder phagocytic cells, neutrophils are recruited in large numbers to the periodontal pocket, where they play a crucial role in the innate defense of the periodontium. Thus, in order to colonize, successful periodontal pathogens must devise means to interfere with neutrophil chemotaxis and activation. In this study, we assessed major neutrophil functions, including degranulation and cell migration, associated with the p38 mitogen-activated protein kinase (MAPK) signaling pathway upon challenge with F. alocis. Under conditions lacking a chemotactic gradient, F. alocis -challenged neutrophils had increased migration compared to uninfected cells, indicating that F. alocis increases chemokinesis in human neutrophils. In addition, neutrophil chemotaxis induced by interleukin-8 was significantly enhanced when cells were challenged with F. alocis , compared to noninfected cells. Similar to live bacteria, heat-killed F. alocis induced both random and directed migration of human neutrophils. The interaction of F. alocis with Toll-like receptor 2 induced granule exocytosis along with a transient ERK1/2 and sustained p38 MAPK activation. Moreover, F. alocis -induced secretory vesicle and specific granule exocytosis were p38 MAPK dependent. Blocking neutrophil degranulation with TAT-SNAP23 fusion protein significantly reduced the chemotactic and random migration induced by F. alocis . Therefore, we propose that induction of random migration by F. alocis will prolong neutrophil traffic time in the gingival tissue, and subsequent degranulation will contribute to tissue damage.

scholarly journals Inhibition of Neutrophil Primary Granule Release during Yersinia pestis Pulmonary Infection

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Kara R. Eichelberger ◽  
Grant S. Jones ◽  
William E. Goldman
Keyword(s):  
Yersinia Pestis ◽  
Critical Role ◽  
Immune Defense ◽  
Calcium Flux ◽  
Human Neutrophils ◽  
Pneumonic Plague ◽  
Content Type ◽  
Neutrophil Degranulation ◽  
Primary Granule ◽  
Granule Release

ABSTRACT Inhalation of Yersinia pestis causes primary pneumonic plague, the most severe manifestation of plague that is characterized by a dramatic neutrophil influx to the lungs. Neutrophils are ineffective during primary pneumonic plague, failing to control Y. pestis growth in the airways. However, the mechanisms by which Y. pestis resists neutrophil killing are incompletely understood. Here, we show that Y. pestis inhibits neutrophil degranulation, an important line of host innate immune defense. We observed that neutrophils from the lungs of mice infected intranasally with Y. pestis fail to release primary granules throughout the course of disease. Using a type III secretion system (T3SS) injection reporter strain, we determined that Y. pestis directly inhibits neutrophil granule release by a T3SS-dependent mechanism. Combinatorial mutant analysis revealed that a Y. pestis strain lacking both effectors YopE and YopH did not inhibit primary granule release and is killed by neutrophils both in vivo and in vitro. Similarly, Y. pestis strains injecting only YopE or YopH are able to inhibit the majority of primary granule release from human neutrophils. We determined that YopE and YopH block Rac2 activation and calcium flux, respectively, to inhibit neutrophil primary granule release in isolated human neutrophils. These results demonstrate that Y. pestis coordinates the inhibition of neutrophil primary granule release through the activities of two distinct effectors, and this inhibition promotes Y. pestis survival during primary pneumonic plague. IMPORTANCE Yersinia pestis is the causative agent of plague and is one of the deadliest human pathogens. The pneumonic form of Y. pestis infection has played a critical role in the severity of both historical and modern plague outbreaks, yet the host-pathogen interactions that govern the lethality of Yersinia pestis pulmonary infections are incompletely understood. Here, we report that Yersinia pestis inhibits neutrophil degranulation during infection, rendering neutrophils ineffective and allowing unrestricted growth of Y. pestis in the lungs. This coordinated inhibition of granule release not only demonstrates the pathogenic benefit of “silencing” lung neutrophils but also reveals specific host processes and pathways that could be manipulated to reduce the severity of primary pneumonic plague.

scholarly journals Proteome Analysis of Coinfection of Epithelial Cells with Filifactor alocis and Porphyromonas gingivalis Shows Modulation of Pathogen and Host Regulatory Pathways

2014 ◽  
Vol 82 (8) ◽  
pp. 3261-3274 ◽  
Author(s):  
A. Wilson Aruni ◽  
Kangling Zhang ◽  
Yuetan Dou ◽  
Hansel Fletcher
Keyword(s):  
Epithelial Cells ◽  
Porphyromonas Gingivalis ◽  
Epigenetic Modification ◽  
Polymicrobial Infection ◽  
Host Cells ◽  
Periodontal Pocket ◽  
Membrane Microdomains ◽  
Content Type ◽  
Regulatory Pathways ◽  
Filifactor Alocis

ABSTRACTChanges in periodontal status are associated with shifts in the composition of the bacterial community in the periodontal pocket. The relative abundances of several newly recognized microbial species, includingFilifactor alocis, as-yet-unculturable organisms, and other fastidious organisms have raised questions on their impact on disease development. We have previously reported that the virulence attributes ofF. alocisare enhanced in coculture withPorphyromonas gingivalis. We have evaluated the proteome of host cells andF. alocisduring a polymicrobial infection. Coinfection of epithelial cells withF. alocisandP. gingivalisstrains showed approximately 20% to 30% more proteins than a monoinfection. UnlikeF. alocisATCC 35896, the D-62D strain expressed more proteins during coculture withP. gingivalisW83 than withP. gingivalis33277. Proteins designated microbial surface component-recognizing adhesion matrix molecules (MSCRAMMs) and cell wall anchor proteins were highly upregulated during the polymicrobial infection. Ultrastructural analysis of the epithelial cells showed formation of membrane microdomains only during coinfection. The proteome profile of epithelial cells showed proteins related to cytoskeletal organization and gene expression and epigenetic modification to be in high abundance. Modulation of proteins involved in apoptotic and cell signaling pathways was noted during coinfection. The enhanced virulence potential ofF. alocismay be related to the differential expression levels of several putative virulence factors and their effects on specific host cell pathways.

scholarly journals Leptin Receptor Mutation Results in Defective Neutrophil Recruitment to the Colon during Entamoeba histolytica Infection

mBio ◽  
2014 ◽  
Vol 5 (6) ◽  
Author(s):  
Caitlin Naylor ◽  
Stacey Burgess ◽  
Rajat Madan ◽  
Erica Buonomo ◽  
Khadija Razzaq ◽  
...  
Keyword(s):  
Entamoeba Histolytica ◽  
Leptin Receptor ◽  
Neutrophil Infiltration ◽  
Neutrophil Function ◽  
Enteric Infection ◽  
Neutrophil Chemotaxis ◽  
Content Type ◽  
Innate Defense ◽  
The Impact ◽  
Increased Susceptibility

ABSTRACTAmebiasis is an enteric infection caused byEntamoeba histolytica, with symptoms ranging in severity from asymptomatic colonization to dysentery. Humans with the Q223R leptin receptor mutation have increased susceptibility to amebiasis, but the mechanism has been unclear. Using a mouse model expressing the mutation, we tested the impact of the Q223R mutation on the innate immune response toE. histolyticainfection. The 223R mutation resulted in delayed clearance of amebae from the cecum, as had been previously observed. We found that neutrophil influx to the site of the infection was reduced 12 h after infection in 223R mice. Depletion of neutrophils with anti-Ly6G monoclonal antibody increased susceptibility of wild-type mice to infection, supporting the importance of neutrophils in innate defense. Leptin expression was increased in the cecum byE. histolyticainfection, suggesting that leptin could serve as a homing signal for neutrophils to the gut. Interestingly, neutrophils from mice with the 223R mutation had diminished chemotaxis toward leptin. This impaired chemotaxis likely explained the reduced gut infiltration of neutrophils. The newly recognized effect of the leptin receptor Q223R mutation on neutrophil chemotaxis and the impact of this mutation on multiple infectious diseases suggest a broader impact of this mutation on susceptibility to disease.IMPORTANCEThe Q223R leptin receptor mutation results in increased susceptibility of children and adults toE. histolytica, one of the leading causes of diarrhea morbidity and mortality in children of the developing world. Here we show that the mutation results in reduced neutrophil infiltration to the site of infection. This decreased infiltration is likely due to the mutation’s impact on neutrophil chemotaxis toward leptin, an inflammatory agent upregulated in the cecum after infection. The significance of this work thus extends beyond understandingE. histolyticasusceptibility by also providing insight into the potential impact of leptin on neutrophil function in other states of altered leptin signaling, which include both malnutrition and obesity.

scholarly journals Filifactor alocis Has Virulence Attributes That Can Enhance Its Persistence under Oxidative Stress Conditions and Mediate Invasion of Epithelial Cells by Porphyromonas gingivalis

2011 ◽  
Vol 79 (10) ◽  
pp. 3872-3886 ◽  
Author(s):  
A. Wilson Aruni ◽  
Francis Roy ◽  
H. M. Fletcher
Keyword(s):  
Oxidative Stress ◽  
Epithelial Cells ◽  
Porphyromonas Gingivalis ◽  
Virulence Factors ◽  
Clinical Isolates ◽  
Periodontal Pocket ◽  
Periodontal Pathogens ◽  
Content Type ◽  
Invasive Capacity ◽  
Filifactor Alocis

ABSTRACTFilifactor alocis, a Gram-positive anaerobic rod, is one of the most abundant bacteria identified in the periodontal pockets of periodontitis patients. There is a gap in our understanding of its pathogenicity and ability to interact with other periodontal pathogens. To evaluate the virulence potential ofF. alocisand its ability to interact withPorphyromonas gingivalisW83, several clinical isolates ofF. alociswere characterized.F. alocisshowed nongingipain protease and sialidase activities.In silicoanalysis revealed the molecular relatedness of several virulence factors fromF. alocisandP. gingivalis. In contrast toP. gingivalis,F. alociswas relatively resistant to oxidative stress and its growth was stimulated under those conditions. Biofilm formation was significantly increased in coculture. There was an increase in adherence and invasion of epithelial cells in coculture compared withP. gingivalisorF. alocismonocultures. In those epithelial cells, endocytic vesicle-mediated internalization was observed only during coculture. TheF. alocisclinical isolate had an increased invasive capacity in coculture withP. gingivaliscompared to the ATCC 35896 strain. In addition, there was variation in the proteomes of the clinical isolates compared to the ATCC 35896 strain. Hypothetical proteins and those known to be important virulence factors in other bacteria were identified. These results indicate thatF. alocishas virulence properties that may enhance its ability to survive and persist in the periodontal pocket and may play an important role in infection-induced periodontal disease.

scholarly journals Filifactor alocis manipulates human neutrophils affecting their ability to release neutrophil extracellular traps induced by PMA

2018 ◽  
Vol 24 (4) ◽  
pp. 210-220 ◽  
Author(s):  
Cortney L Armstrong ◽  
Christopher K Klaes ◽  
Aruna Vashishta ◽  
Richard J Lamont ◽  
Silvia M Uriarte
Keyword(s):  
Neutrophil Elastase ◽  
Neutrophil Extracellular Traps ◽  
Periodontal Pathogen ◽  
Periodontal Pocket ◽  
Human Neutrophils ◽  
Streptococcus Gordonii ◽  
Periodontal Health ◽  
Extracellular Traps ◽  
Tnf Α ◽  
Filifactor Alocis

Neutrophils operate at the site of injury or inflammation in the periodontal pocket to ensure periodontal health and clearance of bacterial pathogens. Filifactor alocis is recently identified as a potential periodontal pathogen, and in this study, we assessed the formation of neutrophil extracellular traps (NETs), in response to the presence of the organism . NET formation by human neutrophils was not induced when challenged with F. alocis, independent of opsonization, viability, time, or bacterial dose. F. alocis also failed to induce NETs from TNF-α-primed neutrophils and did not induce the release of extracellular neutrophil elastase. However, significant NET induction was observed when neutrophils were challenged with Streptococcus gordonii or Peptoanaerobacter stomatis, In addition, co-infection studies revealed that the presence of F. alocis with S. gordonii or P. stomatis does not enhance or reduce NETs. Additionally, F. alocis failed to impact pre-formed NETs induced by either S. gordonii or P. stomatis. Pretreatment with F. alocis prior to stimulation with phorbol 12-myristate 13-acetate (PMA), S. gordonii, or P. stomatis revealed that the bacterium is capable of reducing only PMA but not S. gordonii or P. stomatis NET formation. These results indicate that F. alocis manipulates neutrophils, inhibiting the triggering of NET induction.

The Inhibitory Effect of Heparin and Related Glycosaminoglycans on Neutrophil Chemotaxis

1984 ◽  
Vol 52 (02) ◽  
pp. 134-137 ◽  
Author(s):  
Yaacov Matzner ◽  
Gerard Marx ◽  
Ruth Drexler ◽  
Amiram Eldor
Keyword(s):  
Specific Binding ◽  
Anticoagulant Activity ◽  
Neutrophil Migration ◽  
Inhibitory Effect ◽  
Chemotactic Factor ◽  
Human Neutrophils ◽  
Boyden Chamber ◽  
Neutrophil Chemotaxis ◽  
Inhibitory Effects ◽  
Chemotactic Factors

SummaryClinical observations have shown that heparin has antiinflammatory activities. The effect of heparin on neutrophil chemotaxis was evaluated in vitro in the Boyden Chamber. This method enabled differentiation between the direct effects of heparin on neutrophil migration and locomotion, and its effects on chemotactic factors. Heparin inhibited both the random migration and directed locomotion of human neutrophils toward zymosan-activated serum (ZAS) and F-met-leu-phe (FMLP). Inhibition was found to be dependent on the concentrations of the heparin and of the chemotactic factors. No specific binding of heparin to the neutrophils could be demonstrated, and heparin’s inhibitory effects were eliminated by simple washing of the cells. When added directly to the chamber containing chemotactic factor, heparin inhibited the chemotactic activity of ZAS but not that of FMLP, suggesting a direct inhibitory effect against C5a, the principal chemotactic factor in ZAS.Experiments performed with low-molecular-weight heparin, N-desulfated heparin, dextran sulfate, chondroitin sulfate and dextran indicated that the inhibitory effects of heparin on neutrophil chemotaxis are not related to its anticoagulant activity, but probably depend on the degree of sulfation of the heparin molecule.

scholarly journals Counterregulation of clathrin-mediated endocytosis by the actin and microtubular cytoskeleton in human neutrophils

2009 ◽  
Vol 296 (4) ◽  
pp. C857-C867 ◽  
Author(s):  
Silvia M. Uriarte ◽  
Neelakshi R. Jog ◽  
Gregory C. Luerman ◽  
Samrath Bhimani ◽  
Richard A. Ward ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Actin Cytoskeleton ◽  
Human Neutrophils ◽  
Functional Responses ◽  
Membrane Expression ◽  
Granule Exocytosis ◽  
Plasma Membrane Expression ◽  
Microtubular Cytoskeleton ◽  
Latrunculin A ◽  
Azurophil Granule

We have recently reported that disruption of the actin cytoskeleton enhanced N-formylmethionyl-leucyl-phenylalanine (fMLP)-stimulated granule exocytosis in human neutrophils but decreased plasma membrane expression of complement receptor 1 (CR1), a marker of secretory vesicles. The present study was initiated to determine if reduced CR1 expression was due to fMLP-stimulated endocytosis, to determine the mechanism of this endocytosis, and to examine its impact on neutrophil functional responses. Stimulation of neutrophils with fMLP or ionomycin in the presence of latrunculin A resulted in the uptake of Alexa fluor 488-labeled albumin and transferrin and reduced plasma membrane expression of CR1. These effects were prevented by preincubation of the cells with sucrose, chlorpromazine, or monodansylcadaverine (MDC), inhibitors of clathrin-mediated endocytosis. Sucrose, chlorpromazine, and MDC also significantly inhibited fMLP- and ionomycin-stimulated specific and azurophil granule exocytosis. Disruption of microtubules with nocodazole inhibited endocytosis and azurophil granule exocytosis stimulated by fMLP in the presence of latrunculin A. Pharmacological inhibition of phosphatidylinositol 3-kinase, ERK1/2, and PKC significantly reduced fMLP-stimulated transferrin uptake in the presence of latrunculin A. Blockade of clathrin-mediated endocytosis had no significant effect on fMLP-stimulated phosphorylation of ERK1/2 in neutrophils pretreated with latrunculin A. From these data, we conclude that the actin cytoskeleton functions to limit microtubule-dependent, clathrin-mediated endocytosis in stimulated human neutrophils. The limitation of clathrin-mediated endocytosis by actin regulates the extent of both specific and azurophilic granule exocytosis.

Abrogation of NF-κB signaling in human neutrophils induces neutrophil survival through sustained p38-MAPK activation

2010 ◽  
Vol 88 (4) ◽  
pp. 655-664 ◽  
Author(s):  
Jeroen D. Langereis ◽  
Hanneke A. J. A. Raaijmakers ◽  
Laurien H. Ulfman ◽  
Leo Koenderman
Keyword(s):  
P38 Mapk ◽  
Human Neutrophils ◽  
Mapk Activation ◽  
Neutrophil Survival

Neutrophil chemotaxis, random migration, and adherence in patients with hyperthyroidism

1989 ◽  
Vol 121 (6) ◽  
pp. 817-820 ◽  
Author(s):  
B. Wolach ◽  
B. Lebanon ◽  
A. Jedeikin ◽  
M. S. Shapiro ◽  
L. Shenkman
Keyword(s):  
Thyroid Function ◽  
Chemotactic Activity ◽  
Neutrophil Chemotaxis ◽  
Phagocytic Cells ◽  
Random Migration ◽  
Significant Difference ◽  
Neutrophil Adherence ◽  
Hyperthyroid Patients ◽  
Normal Controls ◽  
Neutrophil Chemotactic Activity

Abstract. We have examined neutrophil adherence, chemotactic activity, and random migration in 35 hyperthyroid patients with Graves' disease and 106 normal volunteers. No statistically significant differences were found between granulocyte adherence of 17 hyperthyroid subjects (67 ± 15.6%) and 81 healthy volunteers (63.1 ± 17%). In 3 thyrotoxic patients, impaired neutrophil adherence was found, which resolved when thyroid function returned to normal. The neutrophil chemotactic activity of 32 normal controls was 107.5 ± 21.4 cells, and the random migration 36 ± 15.5 cells. No statistically significant difference was demonstrated in 13 hyperthyroid patients who had a neutrophil chemotactic activity of 102 ± 14.6 cells and a random migration of 31.2 ± 13.2 cells. Defective chemotactic activity and random migration was found in 2 patients. Neutrophil functions returned to normal in one of the two subjects who were re-evaluated when thyroid function recovered. In summary, 14% of hyperthyroid patients had impaired leukocyte functions. However, severe pyogenic infections are quite rare in hyperthyroid patients, indicating that the observed alterations in function of phagocytic cells are not clinically important.

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