scholarly journals The K1K2 Region of Lys-Gingipain of Porphyromonas gingivalis Blocks Induction of HLA Expression by Gamma Interferon

2012 ◽  
Vol 80 (10) ◽  
pp. 3733-3741 ◽  
Author(s):  
Peter L. Yun ◽  
Nan Li ◽  
Charles A. Collyer ◽  
Neil Hunter
Keyword(s):  
Porphyromonas Gingivalis ◽  
Catalytic Domain ◽  
Umbilical Vein ◽  
Gamma Interferon ◽  
Recent Analysis ◽  
Carbohydrate Binding ◽  
Content Type ◽  
Binding Domains ◽  
Ifn Γ ◽  
Umbilical Vein Endothelial Cells

ABSTRACTIn the context of periodontal disease, cysteine proteinases or gingipains fromPorphyromonas gingivalishave been implicated in the hydrolysis of cytokines, including gamma interferon (IFN-γ). This cytokine plays a crucial role in host defenses, in part, by regulating expression of major histocompatibility complex molecules. Our recent analysis has identified three structurally defined modules, K1, K2, and K3, of the hemagglutinin region of the lysine gingipain Kgp. These three structurally homologous domains have a common β-sandwich topology that is similar to that found in a superfamily of adhesins and carbohydrate binding domains. The three Kgp hemagglutinin modules are distinguished by variation in some of the loops projecting from the β-sandwich core. Recombinant products corresponding to both single and multidomain regions as well as native Kgp bound IFN-γ with similar affinities. Among the adhesin domain constructs, only the K1K2 polypeptide inhibited the upregulation of HLA-1 expression in a human erythroleukemia (K562) line induced by both recombinant and native IFN-γ. The K1K2 polypeptide also inhibited HLA-DR expression induced by IFN-γ in human umbilical vein endothelial cells. These effects were competitively inhibited by coincubation with sodium or potassium chloride solution. The N-terminal residues of IFN-γ were implicated in mediating the effect of K1K2, while antibody binding to loop 1 of K2 blocked the action of K1K2. The findings indicate the potential significance of structurally defined Kgp adhesin modules in the inactivation of IFN-γ but also the potential of K1K2 in locating the target for the catalytic domain of Kgp.

scholarly journals Gamma Interferon Confers Resistance to Infection with Staphylococcus aureus in Human Vascular Endothelial Cells by Cooperative Proinflammatory and Enhanced Intrinsic Antibacterial Activities

2007 ◽  
Vol 75 (12) ◽  
pp. 5615-5626 ◽  
Author(s):  
Henry Beekhuizen ◽  
Joke S. van de Gevel
Keyword(s):  
Staphylococcus Aureus ◽  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Protective Efficacy ◽  
Umbilical Vein ◽  
Effective Means ◽  
Antibacterial Activities ◽  
Gamma Interferon ◽  
Ifn Γ ◽  
Umbilical Vein Endothelial Cells

ABSTRACT Vascular endothelium is an exposed target in systemic endovascular Staphylococcus aureus infections. We reported earlier that the proinflammatory and procoagulant activities of primary human umbilical vein endothelial cells (ECs) after binding and ingestion of S. aureus organisms provide the cells effective means for leukocyte-mediated bacterial elimination. Expanding on this, we now show that these ECs exhibit a modest intrinsic capacity for eliminating intracellular S. aureus that was influenced by cytokines relevant to S. aureus infections. Using various EC infection assays, we showed that gamma interferon (IFN-γ), applied to cultures of ECs prior to or after infection with S. aureus, markedly reduced the level of infection, illustrated by lower percentages of S. aureus-infected ECs and less intracellular bacteria per infected cell. IFN-γ-activated ECs had unaltered abilities to bind S. aureus and processed ingested bacteria by a seemingly conventional phagocytic pathway. IFN-γ treatment rescued EC monolayers from severe injury by virulent clinical S. aureus strains or excessive bacterial numbers. Mechanistically, IFN-γ controls S. aureus infection via IFN-γ receptor, most likely through stimulation of intrinsic endothelial antibacterial mechanisms but independent of processes that deprive bacteria of intracellular l-tryptophan or iron. The antibacterial activity of IFN-γ-stimulated ECs coincided with sustained or slightly elevated endothelial proinflammatory responses that supported monocyte recruitment. In conclusion, we identify IFN-γ as a potent regulatory Th1 cytokine possessing exclusive abilities to augment intrinsic antistaphylocccal effector mechanisms in human ECs without ablating the S. aureus-induced proinflammatory EC responses and, as such, coordinating a protective efficacy of ECs against blood-borne S. aureus infection.

scholarly journals E-Selectin Mediates Porphyromonas gingivalis Adherence to Human Endothelial Cells

2012 ◽  
Vol 80 (7) ◽  
pp. 2570-2576 ◽  
Author(s):  
Toshinori Komatsu ◽  
Keiji Nagano ◽  
Shinsuke Sugiura ◽  
Makoto Hagiwara ◽  
Naomi Tanigawa ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Porphyromonas Gingivalis ◽  
Umbilical Vein ◽  
Vascular Inflammation ◽  
Periodontal Pathogen ◽  
Sialyl Lewis X ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Tnf Α ◽  
Umbilical Vein Endothelial Cells

ABSTRACTPorphyromonas gingivalis, a major periodontal pathogen, may contribute to atherogenesis and other inflammatory cardiovascular diseases. However, little is known about interactions betweenP. gingivalisand endothelial cells. E-selectin is a membrane protein on endothelial cells that initiates recruitment of leukocytes to inflamed tissue, and it may also play a role in pathogen attachment. In the present study, we examined the role of E-selectin inP. gingivalisadherence to endothelial cells. Human umbilical vein endothelial cells (HUVECs) were stimulated with tumor necrosis factor alpha (TNF-α) to induce E-selectin expression. Adherence ofP. gingivalisto HUVECs was measured by fluorescence microscopy. TNF-α increased adherence of wild-typeP. gingivalisto HUVECs. Antibodies to E-selectin and sialyl Lewis X suppressedP. gingivalisadherence to stimulated HUVECs.P. gingivalismutants lacking OmpA-like proteins Pgm6 and -7 had reduced adherence to stimulated HUVECs, but fimbria-deficient mutants were not affected. E-selectin-mediatedP. gingivalisadherence activated endothelial exocytosis. These results suggest that the interaction between host E-selectin and pathogen Pgm6/7 mediatesP. gingivalisadherence to endothelial cells and may trigger vascular inflammation.

scholarly journals Modulation of an Interleukin-12 and Gamma Interferon Synergistic Feedback Regulatory Cycle of T-Cell and Monocyte Cocultures by Porphyromonas gingivalis Lipopolysaccharide in the Absence or Presence of Cysteine Proteinases

2002 ◽  
Vol 70 (10) ◽  
pp. 5695-5705 ◽  
Author(s):  
Peter L. W. Yun ◽  
Arthur A. DeCarlo ◽  
Charles Collyer ◽  
Neil Hunter
Keyword(s):  
T Cells ◽  
T Cell ◽  
Porphyromonas Gingivalis ◽  
Gamma Interferon ◽  
Periodontal Pathogen ◽  
Interleukin 12 ◽  
Minor Role ◽  
Cysteine Proteinases ◽  
Activated T Cells ◽  
Ifn Γ

ABSTRACT Interleukin 12 (IL-12) is an efficient inducer and enhancer of gamma interferon (IFN-γ) production by both resting and activated T cells. There is evidence that human monocytes exposed to IFN-γ have enhanced ability to produce IL-12 when stimulated with lipopolysaccharide (LPS). In this study, it was demonstrated that LPS from the oral periodontal pathogen Porphyromonas gingivalis stimulated monocytes primed with IFN-γ to release IL-12, thereby enhancing IFN-γ accumulation in T-cell populations. P. gingivalis LPS was shown to enhance IL-12 induction of IFN-γ in T cells in a manner independent from TNF-α contribution. The levels of T-cell IL-12 receptors were not affected by P. gingivalis LPS and played only a minor role in the magnitude of the IFN-γ response. These data suggest that LPS from P. gingivalis establishes an activation loop with IL-12 and IFN-γ with potential to augment the production of inflammatory cytokines in relation to the immunopathology of periodontitis. We previously reported that the major cysteine proteinases (gingipains) copurifying with LPS in this organism were responsible for reduced IFN-γ accumulation in the presence of IL-12. However, the addition of the gingipains in the presence of LPS resulted in partial restoration of the IFN-γ levels. In the destructive periodontitis lesion, release of gingipains from the outer membrane (OM) of P. gingivalis could lead to the downregulation of Th1 responses, while gingipain associated with LPS in the OM or in OM vesicles released from the organism could have net stimulatory effects.

scholarly journals Carbohydrate‐binding domains facilitate efficient oligosaccharides synthesis by enhancing mutant catalytic domain transglycosylation activity

2020 ◽  
Vol 117 (10) ◽  
pp. 2944-2956 ◽  
Author(s):  
Chandra Kanth Bandi ◽  
Antonio Goncalves ◽  
Sai Venkatesh Pingali ◽  
Shishir P. S. Chundawat
Keyword(s):  
Catalytic Domain ◽  
Carbohydrate Binding ◽  
Binding Domains ◽  
Transglycosylation Activity

scholarly journals Glucoamylase starch-binding domain of Aspergillus niger B1: molecular cloning and functional characterization

2003 ◽  
Vol 372 (3) ◽  
pp. 905-910 ◽  
Author(s):  
Tzur PALDI ◽  
Ilan LEVY ◽  
Oded SHOSEYOV
Keyword(s):  
Aspergillus Niger ◽  
Corn Starch ◽  
Catalytic Domain ◽  
Functional Characterization ◽  
Carbohydrate Binding ◽  
Amylolytic Enzymes ◽  
Binding Domains ◽  
C Terminus ◽  
Carbohydrate Binding Modules ◽  
Modified Starches

Carbohydrate-binding modules (CBMs) are protein domains located within a carbohydrate-active enzyme, with a discrete fold that can be separated from the catalytic domain. Starch-binding domains (SBDs) are CBMs that are usually found at the C-terminus in many amylolytic enzymes. The SBD from Aspergillus niger B1 (CMI CC 324262) was cloned and expressed in Escherichia coli as an independent domain and the recombinant protein was purified on starch. The A. niger B1 SBD was found to be similar to SBD from A. kawachii, A. niger var. awamori and A. shirusami (95–96% identity) and was classified as a member of the CBM family 20. Characterization of SBD binding to starch indicated that it is essentially irreversible and that its affinity to cationic or anionic starch, as well as to potato or corn starch, does not differ significantly. These observations indicate that the fundamental binding area on these starches is essentially the same. Natural and chemically modified starches are among the most useful biopolymers employed in the industry. Our study demonstrates that SBD binds effectively to both anionic and cationic starch.

scholarly journals Structural insight into industrially relevant glucoamylases: flexible positions of starch-binding domains

2018 ◽  
Vol 74 (5) ◽  
pp. 463-470 ◽  
Author(s):  
Christian Roth ◽  
Olga V. Moroz ◽  
Antonio Ariza ◽  
Lars K. Skov ◽  
Keiichi Ayabe ◽  
...  
Keyword(s):  
Catalytic Domain ◽  
Relative Concentration ◽  
Spatial Arrangement ◽  
Carbohydrate Binding ◽  
Polymeric Substrate ◽  
Binding Domains ◽  
Catalytic Mechanisms ◽  
The Individual ◽  
First Time ◽  
Insight Into

Glucoamylases are one of the most important classes of enzymes in the industrial degradation of starch biomass. They consist of a catalytic domain and a carbohydrate-binding domain (CBM), with the latter being important for the interaction with the polymeric substrate. Whereas the catalytic mechanisms and structures of the individual domains are well known, the spatial arrangement of the domains with respect to each other and its influence on activity are not fully understood. Here, the structures of three industrially used fungal glucoamylases, two of which are full length, have been crystallized and determined. It is shown for the first time that the relative orientation between the CBM and the catalytic domain is flexible, as they can adopt different orientations independently of ligand binding, suggesting a role as an anchor to increase the contact time and the relative concentration of substrate near the active site. The flexibility in the orientations of the two domains presented a considerable challenge for the crystallization of the enzymes.

scholarly journals Gamma Interferon Is Required for Chlamydia Clearance but Is Dispensable for T Cell Homing to the Genital Tract

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Jennifer D. Helble ◽  
Rodrigo J. Gonzalez ◽  
Ulrich H. von Andrian ◽  
Michael N. Starnbach
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Chlamydia Trachomatis ◽  
Genital Tract ◽  
Gamma Interferon ◽  
Cell Homing ◽  
Content Type ◽  
T Cell Homing ◽  
Ifn Γ

ABSTRACT While there is no effective vaccine against Chlamydia trachomatis infection, previous work has demonstrated the importance of C. trachomatis-specific CD4+ T cells (NR1 T cells) in pathogen clearance. Specifically, NR1 T cells have been shown to be protective in mice, and this protection depends on the host’s ability to sense the cytokine gamma interferon (IFN-γ). However, it is unclear what role NR1 production or sensing of IFN-γ plays in T cell homing to the genital tract or T cell-mediated protection against C. trachomatis. Using two-photon microscopy and flow cytometry, we found that naive wild-type (WT), IFN-γ−/−, and IFN-γR−/− NR1 T cells specifically home to sections in the genital tract that contain C. trachomatis. We also determined that protection against infection requires production of IFN-γ from either NR1 T cells or endogenous cells, further highlighting the importance of IFN-γ in clearing C. trachomatis infection. IMPORTANCE Chlamydia trachomatis is an important mucosal pathogen that is the leading cause of sexually transmitted bacterial infections in the United States. Despite this, there is no vaccine currently available. In order to develop such a vaccine, it is necessary to understand the components of the immune response that can lead to protection against this pathogen. It is well known that antigen-specific CD4+ T cells are critical for Chlamydia clearance, but the contexts in which they are protective or not protective are unknown. Here, we aimed to characterize the importance of gamma interferon production and sensing by T cells and the effects on the immune response to C. trachomatis. Our work here helps to define the contexts in which antigen-specific T cells can be protective, which is critical to our ability to design an effective and protective vaccine against C. trachomatis.

scholarly journals GABARAPL2 Is Critical for Growth Restriction of Toxoplasma gondii in HeLa Cells Treated with Gamma Interferon

2020 ◽  
Vol 88 (5) ◽  
Author(s):  
Zhaoxia Zhang ◽  
Haorong Gu ◽  
Qi Li ◽  
Jun Zheng ◽  
Shinuo Cao ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Hela Cells ◽  
Critical Role ◽  
Gamma Interferon ◽  
Growth Restriction ◽  
Membrane Structures ◽  
Content Type ◽  
Receptor Associated Protein ◽  
Ifn Γ ◽  
And Function

ABSTRACT Gamma interferon (IFN-γ)-induced innate immune responses play important roles in the inhibition of Toxoplasma gondii infection. It has been reported that IFN-γ stimulates non-acidification-dependent growth restriction of T. gondii in HeLa cells, but the mechanism remains unclear. Here, we found that γ-aminobutyric acid (GABA) receptor-associated protein-like 2 (GABARAPL2) plays a critical role in parasite restriction in IFN-γ-treated HeLa cells. GABARAPL2 is recruited to membrane structures surrounding parasitophorous vacuoles (PV). Autophagy adaptors are required for the proper localization and function of GABARAPL2 in the IFN-γ -induced immune response. These findings provide further understanding of a noncanonical autophagy pathway responsible for IFN-γ-dependent inhibition of T. gondii growth in human HeLa cells and demonstrate the critical role of GABARAPL2 in this response.

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