scholarly journals Staphylococcus aureus ATP Synthase Promotes Biofilm Persistence by Influencing Innate Immunity

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Megan E. Bosch ◽  
Blake P. Bertrand ◽  
Cortney E. Heim ◽  
Abdulelah A. Alqarzaee ◽  
Sujata S. Chaudhari ◽  
...  
Keyword(s):  
Immune Response ◽  
Atp Synthase ◽  
Proinflammatory Cytokine ◽  
Cytokine Production ◽  
Joint Infection ◽  
Critical Role ◽  
Host Immune Response ◽  
Proinflammatory Cytokine Production ◽  
Content Type ◽  
Prosthetic Joint

ABSTRACT Staphylococcus aureus is a major cause of prosthetic joint infection (PJI), which is characterized by biofilm formation. S. aureus biofilm skews the host immune response toward an anti-inflammatory profile by the increased recruitment of myeloid-derived suppressor cells (MDSCs) that attenuate macrophage proinflammatory activity, leading to chronic infection. A screen of the Nebraska Transposon Mutant Library identified several hits in the ATP synthase operon that elicited a heightened inflammatory response in macrophages and MDSCs, including atpA, which encodes the alpha subunit of ATP synthase. An atpA transposon mutant (ΔatpA) had altered growth kinetics under both planktonic and biofilm conditions, along with a diffuse biofilm architecture that was permissive for leukocyte infiltration, as observed by confocal laser scanning microscopy. Coculture of MDSCs and macrophages with ΔatpA biofilm elicited significant increases in the proinflammatory cytokines interleukin 12p70 (IL-12p70), tumor necrosis factor alpha (TNF-α), and IL-6. This was attributed to increased leukocyte survival resulting from less toxin and protease production by ΔatpA biofilm as determined by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The enhanced inflammatory response elicited by ΔatpA biofilm was cell lysis-dependent since it was negated by polyanethole sodium sulfanate treatment or deletion of the major autolysin, Atl. In a mouse model of PJI, ΔatpA-infected mice had decreased MDSCs concomitant with increased monocyte/macrophage infiltrates and proinflammatory cytokine production, which resulted in biofilm clearance. These studies identify S. aureus ATP synthase as an important factor in influencing the immune response during biofilm-associated infection and bacterial persistence. IMPORTANCE Medical device-associated biofilm infections are a therapeutic challenge based on their antibiotic tolerance and ability to evade immune-mediated clearance. The virulence determinants responsible for bacterial biofilm to induce a maladaptive immune response remain largely unknown. This study identified a critical role for S. aureus ATP synthase in influencing the host immune response to biofilm infection. An S. aureus ATP synthase alpha subunit mutant (ΔatpA) elicited heightened proinflammatory cytokine production by leukocytes in vitro and in vivo, which coincided with improved biofilm clearance in a mouse model of prosthetic joint infection. The ability of S. aureus ΔatpA to augment host proinflammatory responses was cell lysis-dependent, as inhibition of bacterial lysis by polyanethole sodium sulfanate or a ΔatpAΔatl biofilm did not elicit heightened cytokine production. These studies reveal a critical role for AtpA in shaping the host immune response to S. aureus biofilm.

scholarly journals Toll-Like Receptor 6 Plays an Important Role in Host Innate Resistance to Brucella abortus Infection in Mice

2013 ◽  
Vol 81 (5) ◽  
pp. 1654-1662 ◽  
Author(s):  
Leonardo A. de Almeida ◽  
Gilson C. Macedo ◽  
Fábio A. V. Marinho ◽  
Marco T. R. Gomes ◽  
Patrícia P. Corsetti ◽  
...  
Keyword(s):  
Immune Response ◽  
Dendritic Cells ◽  
Brucella Abortus ◽  
Proinflammatory Cytokine ◽  
Cytokine Production ◽  
Innate Immune ◽  
Proinflammatory Cytokine Production ◽  
Toll Like Receptor ◽  
Content Type

ABSTRACTBrucella abortusis recognized by several Toll-like receptor (TLR)-associated pathways triggering proinflammatory responses that affect both the nature and intensity of the immune response. Previously, we demonstrated thatB. abortus-mediated dendritic cell (DC) maturation and control of infection are dependent on the adaptor molecule MyD88. However, the involvement of all TLRs in response toB. abortusinfection is not completely understood. Therefore, we decided to evaluate the requirement for TLR6 in host resistance toB. abortus. Here, we demonstrated that TLR6 is an important component for triggering an innate immune response againstB. abortus. Anin vitroluciferase assay indicated that TLR6 cooperates with TLR2 to senseBrucellaand further activates NF-κB signaling. However,in vivoanalysis showed that TLR6, not TLR2, is required for the efficient control ofB. abortusinfection. Additionally,B. abortus-infected dendritic cells require TLR6 to induce tumor necrosis factor alpha (TNF-α) and interleukin-12 (IL-12). Furthermore, our findings demonstrated that the mitogen-activated protein kinase (MAPK) signaling pathway is impaired in TLR2, TLR6, and TLR2/6 knockout (KO) DCs when infected withB. abortus, which may account for the lower proinflammatory cytokine production observed in TLR6 KO mouse dendritic cells. In summary, the results presented here indicate that TLR6 is required to trigger innate immune responses againstB. abortusin vivoand is required for the full activation of DCs to induce robust proinflammatory cytokine production.

scholarly journals Immune Recognition of the Epidemic Cystic Fibrosis Pathogen Burkholderia dolosa

2017 ◽  
Vol 85 (6) ◽  
Author(s):  
Damien Roux ◽  
Molly Weatherholt ◽  
Bradley Clark ◽  
Mihaela Gadjeva ◽  
Diane Renaud ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Immune Response ◽  
Cytokine Production ◽  
Cultured Cells ◽  
Host Immune Response ◽  
Host Cells ◽  
Burkholderia Cenocepacia ◽  
Immune Recognition ◽  
Content Type

ABSTRACT Burkholderia dolosa caused an outbreak in the cystic fibrosis (CF) clinic at Boston Children's Hospital from 1998 to 2005 and led to the infection of over 40 patients, many of whom died due to complications from infection by this organism. To assess whether B. dolosa significantly contributes to disease or is recognized by the host immune response, mice were infected with a sequenced outbreak B. dolosa strain, AU0158, and responses were compared to those to the well-studied CF pathogen Pseudomonas aeruginosa. In parallel, mice were also infected with a polar flagellin mutant of B. dolosa to examine the role of flagella in B. dolosa lung colonization. The results showed a higher persistence in the host by B. dolosa strains, and yet, neutrophil recruitment and cytokine production were lower than those with P. aeruginosa. The ability of host immune cells to recognize B. dolosa was then assessed, B. dolosa induced a robust cytokine response in cultured cells, and this effect was dependent on the flagella only when bacteria were dead. Together, these results suggest that B. dolosa can be recognized by host cells in vitro but may avoid or suppress the host immune response in vivo through unknown mechanisms. B. dolosa was then compared to other Burkholderia species and found to induce similar levels of cytokine production despite being internalized by macrophages more than Burkholderia cenocepacia strains. These data suggest that B. dolosa AU0158 may act differently with host cells and is recognized differently by immune systems than are other Burkholderia strains or species.

scholarly journals Candida albicans Cell Wall Glycosylation May Be Indirectly Required for Activation of Epithelial Cell Proinflammatory Responses

2011 ◽  
Vol 79 (12) ◽  
pp. 4902-4911 ◽  
Author(s):  
Celia Murciano ◽  
David L. Moyes ◽  
Manohursingh Runglall ◽  
Ayesha Islam ◽  
Celine Mille ◽  
...  
Keyword(s):  
Cell Wall ◽  
Epithelial Cells ◽  
Proinflammatory Cytokine ◽  
Cytokine Production ◽  
Cell Damage ◽  
Proinflammatory Cytokine Production ◽  
Content Type ◽  
Oral Epithelial Cells ◽  
Hypha Formation ◽  
Oral Epithelial

ABSTRACTOral epithelial cells discriminate between the yeast and hyphal forms ofCandida albicansvia the mitogen-activated protein kinase (MAPK) signaling pathway. This occurs through phosphorylation of the MAPK phosphatase MKP1 and activation of the c-Fos transcription factor by the hyphal form. Given that fungal cell wall polysaccharides are critical in host recognition and immune activation in myeloid cells, we sought to determine whether β-glucan andN- orO-glycosylation was important in activating the MAPK/MKP1/c-Fos hypha-mediated response mechanism and proinflammatory cytokines in oral epithelial cells. Using a series of β-glucan andN- andO-mannan mutants, we found thatN-mannosylation (via Δoch1and Δpmr1mutants) andO-mannosylation (via Δpmt1and Δmnt1Δmnt2mutants), but not phosphomannan (via a Δmnn4mutant) or β-1,2 mannosylation (via Δbmt1to Δbmt6mutants), were required for MKP1/c-Fos activation, proinflammatory cytokine production, and cell damage induction. However, theN- andO-mannan mutants showed reduced adhesion or lack of initial hypha formation at 2 h, resulting in little MKP1/c-Fos activation, or restricted hypha formation/pseudohyphal formation at 24 h, resulting in minimal proinflammatory cytokine production and cell damage. Further, the α-1,6-mannose backbone of theN-linked outer chain (corresponding to a Δmnn9mutant) may be required for epithelial adhesion, while the α-1,2-mannose component of phospholipomannan (corresponding to a Δmit1mutant) may contribute to epithelial cell damage. β-Glucan appeared to play no role in adhesion, epithelial activation, or cell damage. In summary,N- andO-mannosylation defects affect the ability ofC. albicansto induce proinflammatory cytokines and damage in oral epithelial cells, but this may be due to indirect effects on fungal pathogenicity rather than mannose residues being direct activators of the MAPK/MKP1/c-Fos hypha-mediated immune response.

scholarly journals Pentoxifylline Alone or in Combination with Gentamicin or Vancomycin Inhibits Live Microbe-Induced Proinflammatory Cytokine Production in Human Cord Blood and Cord Blood Monocytes In Vitro

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
Esther M. Speer ◽  
Elizabeth Diago-Navarro ◽  
Lukasz S. Ozog ◽  
David J. Dowling ◽  
Wei Hou ◽  
...  
Keyword(s):  
Cord Blood ◽  
Proinflammatory Cytokines ◽  
Proinflammatory Cytokine ◽  
Antimicrobial Agents ◽  
Cytokine Production ◽  
Proinflammatory Cytokine Production ◽  
Human Cord Blood ◽  
Content Type ◽  
E Coli

ABSTRACT Neonatal sepsis and its accompanying inflammatory response contribute to substantial morbidity and mortality. Pentoxifylline (PTX), a phosphodiesterase inhibitor which suppresses transcription and production of proinflammatory cytokines, is a candidate adjunctive therapy for newborn sepsis. We hypothesized that PTX decreases live microbe-induced inflammatory cytokine production in newborn blood. Cord blood was stimulated with live microorganisms commonly encountered in newborn sepsis (Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, or Candida albicans) and simultaneously treated with antimicrobial agents (gentamicin, vancomycin, or amphotericin B) and/or clinically relevant concentrations of PTX. Microbial colony counts were enumerated by plating, supernatant cytokines were measured by multiplex assay, intracellular cytokines and signaling molecules were measured by flow cytometry, and mRNA levels were measured by quantitative reverse transcription-PCR. PTX inhibited concentration-dependent E. coli-, S. aureus-, S. epidermidis-, and C. albicans-induced tumor necrosis factor (TNF) and E. coli-induced interleukin-1β (IL-1β) production in whole blood, with greater suppression of proinflammatory cytokines in combination with antimicrobial agents. Likewise, PTX suppressed E. coli-induced monocytic TNF and IL-1β, whereby combined PTX and gentamicin led to significantly greater reduction of TNF and IL-1β. The anti-inflammatory effect of PTX on microbe-induced proinflammatory cytokine production was accompanied by inhibition of TNF mRNA expression and was achieved without suppressing the production of the anti-inflammatory IL-10. Of note, microbial colony counts in newborn blood were not increased by PTX. Our findings demonstrated that PTX inhibited microbe-induced proinflammatory cytokine production, especially when combined with antimicrobial agents, without enhancing microbial proliferation in human cord blood in vitro, thus supporting its utility as candidate adjunctive agent for newborn sepsis.

scholarly journals AB0108 IRAK4 INHIBITION SUPPRESSES PROINFLAMMATORY CYTOKINE PRODUCTION FROM HUMAN MACROPHAGES STIMULATED WITH SYNOVIAL FLUID FROM RHEUMATOID ARTHRITIS PATIENTS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1353.2-1353
Author(s):  
A. Yadon ◽  
D. Ruelas ◽  
G. Min-Oo ◽  
J. Taylor ◽  
M. R. Warr
Keyword(s):  
Rheumatoid Arthritis ◽  
Synovial Fluid ◽  
Signaling Pathways ◽  
Proinflammatory Cytokines ◽  
Proinflammatory Cytokine ◽  
Cytokine Production ◽  
Interleukin 1 ◽  
Proinflammatory Cytokine Production ◽  
Human Macrophages ◽  
Percent Suppression

Background:Rheumatoid arthritis (RA) is characterized by chronic, uncontrolled joint inflammation and tissue destruction. Macrophages are thought to be key mediators in both the initiation and perpetuation of this pathology.1,2The RA synovium contains a complex inflammatory milieu that can stimulate macrophage-dependent production of proinflammatory cytokines through multiple signaling pathways.1,2Existing evidence indicates that toll-like receptors (TLRs) and interleukin-1 receptors (IL-1R) along with their agonists, damage-associated molecular patterns (DAMPs) and IL-1β, are highly expressed in RA joints and are important mediators of synovial macrophage activation and proinflammatory cytokine production.1-9IRAK4 (interleukin-1 receptor-associated kinase 4) is a serine/threonine kinase that facilitates TLR and IL-1R signaling in many cell types, including macrophages.10IRAK4 inhibition represents an opportunity to reduce proinflammatory cytokine production in the joints of patients with RA.Objectives:To investigate the effect of a highly selective IRAK4 inhibitor on proinflammatory cytokine production from human macrophages stimulated with synovial fluid from patients with RA.Methods:Primary human monocytes from 2 independent donors were differentiated for 6 days with granulocyte-macrophage colony-stimulating factor (GM-CSF) to generate human monocyte-derived macrophages (hMDMs). hMDMs were then pretreated with an IRAK4 inhibitor for 1 hour and subsequently stimulated for 24 hours with RA synovial fluid from 5 patients. Culture supernatants were then assessed for secretion of proinflammatory cytokines by MesoScale Discovery.Results:RA synovial fluid stimulation of hMDMs resulted in the production of several proinflammatory cytokines, including IL-6, IL-8, and TNFα. Pretreatment of hMDMs with an IRAK4 inhibitor resulted in the dose-dependent inhibition of IL-6, IL-8, and TNFα production, with an average EC50± SD of 27 ± 31, 26 ± 41, and 28 ± 22 nM, respectively. Maximal percent suppression ± SD of IL-6, IL-8, and TNFα were 76 ± 8.8, 73 ± 15, and 77 ± 13, respectively. To evaluate the specific IRAK4-dependent signaling pathways mediating this response, hMDMs were pretreated with inhibitors of TLR4 (TAK242) and IL-1R (IL-1RA) prior to stimulation with RA synovial fluid. Both TAK242 and IL-1RA inhibited proinflammatory cytokine production. For TAK242, maximal percent suppression ± SD of IL-6, IL-8, and TNFα were 39 ± 25, 48 ± 24, and 50 ± 21, respectively. For IL-1RA maximal percent suppression ± SD of IL-6, IL-8, and TNFα were 18 ± 18, 20 ± 23, and 16 ± 18, respectively. The broad range of inhibition across each stimulation highlights the complexity and variability in the signaling pathways mediating proinflammatory cytokine production from hMDMs stimulated with RA synovial fluid, but demonstrates that RA synovial fluid can stimulate proinflammatory cytokine production in hMDMs, at least partly, through IRAK4-dependent pathways.Conclusion:This work demonstrates that IRAK4 inhibition can suppress proinflammatory cytokine production from macrophages stimulated with synovial fluid from patients with RA and supports a potential pathophysiological role for IRAK4 in perpetuating chronic inflammation in RA.References:[1]Smolen JS, et al.Nat Rev Dis Primers.2018;4:18001.[2]Udalova IA, et al.Nat Rev Rheumatol.2016;12(8):472-485.[3]Joosten LAB, et al.Nat Rev Rheumatol.2016;12(6):344-357.[4]Huang QQ, Pope RM.Curr Rheumatol Rep.2009;11(5):357-364.[5]Roh JS, Sohn DH.Immune Netw.2018;18(4):e27.[6]Sacre SM, et al.Am J Pathol.2007;170(2):518-525.[7]Ultaigh SNA, et al.Arthritis Res Ther.2011;13(1):R33.[8]Bottini N, Firestein GS.Nat Rev Rheumatol.2013;9(1):24-33.[9]Firestein GS, McInnes IB.Immunity.2017;46(2):183-196.[10]Janssens S, Beyaert R.Mol Cell.2003;11(2):293-302.Disclosure of Interests:Adam Yadon Employee of: Gilead, Debbie Ruelas Employee of: Gilead, Gundula Min-Oo Employee of: Gilead, James Taylor Employee of: Gilead, Matthew R. Warr Employee of: Gilead

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