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  1. Article ; Online: Phosphoinositol 3-kinase-driven NET formation involves different isoforms and signaling partners depending on the stimulus.

    de Carvalho Oliveira, Vanessa / Tatsiy, Olga / McDonald, Patrick P

    Frontiers in immunology

    2023  Volume 14, Page(s) 1042686

    Abstract: Neutrophil extracellular traps (NETs) serve to immobilize and kill pathogens, but also can contribute to the progression of several inflammatory and auto-immune diseases, as well as cancer. Whence the importance of elucidating the mechanisms underlying ... ...

    Abstract Neutrophil extracellular traps (NETs) serve to immobilize and kill pathogens, but also can contribute to the progression of several inflammatory and auto-immune diseases, as well as cancer. Whence the importance of elucidating the mechanisms underlying NET formation. In this regard, the PI3K signaling pathway has been shown to be crucial; yet little is known about which of its components are involved. Here, we identified the PI3K isoforms and associated signaling partners that are mobilized in response to different classes of physiological NET inducers (inflammatory cytokines, growth factors, chemoattractants). NET generation was assessed by microscopy and signalling molecule activation by immunoblot using phospho-antibodies. Across the various stimuli, PI3Kα and PI3Kγ isoforms clearly contributed to NET induction, while the participation of other isoforms was stimulus-dependent. Some PI3K isoforms were also found to signal through Akt, the canonical downstream effector of PI3K, while others did not. Downstream of PI3K, mTOR and PLCγ2 were used by all stimuli to control NET generation. Conversely, the involvement of other kinases depended on the stimulus - both TNFα and GM-CSF relied on PDK1 and Akt; and both TNFα and fMLP additionally used S6K. We further established that all PI3K isoforms and downstream effectors act belatedly in NET generation, as reported previously for PI3K. Finally, we revisited the PI3K-PDK1-Akt signaling hierarchy in human neutrophils and again found stimulus-dependent differences. Our data uncover unsuspected complexity and redundancy in the signaling machinery controlling NET formation through the all-important PI3K pathway. Conserved signaling molecules represent therapeutic targets for pathologies involving NETs and in this regard, the existence of drugs currently used in the clinic or undergoing clinical trials (which target PI3K isoforms, mTOR or Akt), underscores the translational potential of our findings.
    MeSH term(s) Humans ; Phosphatidylinositol 3-Kinases/metabolism ; Protein Isoforms/metabolism ; Proto-Oncogene Proteins c-akt/metabolism ; Signal Transduction ; TOR Serine-Threonine Kinases/metabolism ; Tumor Necrosis Factor-alpha ; Extracellular Traps
    Chemical Substances Phosphatidylinositol 3-Kinases (EC 2.7.1.-) ; Protein Isoforms ; Proto-Oncogene Proteins c-akt (EC 2.7.11.1) ; TOR Serine-Threonine Kinases (EC 2.7.11.1) ; Tumor Necrosis Factor-alpha
    Language English
    Publishing date 2023-01-24
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2606827-8
    ISSN 1664-3224 ; 1664-3224
    ISSN (online) 1664-3224
    ISSN 1664-3224
    DOI 10.3389/fimmu.2023.1042686
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Early and Late Processes Driving NET Formation, and the Autocrine/Paracrine Role of Endogenous RAGE Ligands.

    Tatsiy, Olga / de Carvalho Oliveira, Vanessa / Mosha, Hugo Tshivuadi / McDonald, Patrick P

    Frontiers in immunology

    2021  Volume 12, Page(s) 675315

    Abstract: Neutrophil extracellular trap (NET) formation has emerged as an important response against various pathogens; it also plays a role in chronic inflammation, autoimmunity, and cancer. Despite a growing understanding of the mechanisms underlying NET ... ...

    Abstract Neutrophil extracellular trap (NET) formation has emerged as an important response against various pathogens; it also plays a role in chronic inflammation, autoimmunity, and cancer. Despite a growing understanding of the mechanisms underlying NET formation, much remains to be elucidated. We previously showed that in human neutrophils activated with different classes of physiological stimuli, NET formation features both early and late events that are controlled by discrete signaling pathways. However, the nature of these events has remained elusive. We now report that PAD4 inhibition only affects the early phase of NET generation, as do distinct signaling intermediates (TAK1, MEK, p38 MAPK). Accordingly, the inducible citrullination of residue R2 on histone H3 is an early neutrophil response that is regulated by these kinases; other arginine residues on histones H3 and H4 do not seem to be citrullinated. Conversely, elastase blockade did not affect NET formation by several physiological stimuli, though it did so in PMA-activated cells. Among belated events in NET formation, we found that chromatin decondensation is impaired by the inhibition of signaling pathways controlling both early and late stages of the phenomenon. In addition to chromatin decondensation, other late processes were uncovered. For instance, unstimulated neutrophils can condition themselves to be poised for rapid NET induction. Similarly, activated neutrophils release endogenous proteic factors that promote and largely mediate NET generation. Several such factors are known RAGE ligands and accordingly, RAGE inbibition largely prevents both NET formation and the conditioning of neutrophils to rapidly generate NETs upon stimulation. Our data shed new light on the cellular processes underlying NET formation, and unveil unsuspected facets of the phenomenon that could serve as therapeutic targets. In view of the involvement of NETs in both homeostasis and several pathologies, our findings are of broad relevance.
    MeSH term(s) Antigens, Neoplasm/genetics ; Antigens, Neoplasm/immunology ; Chromatin/immunology ; Citrullination/genetics ; Citrullination/immunology ; Extracellular Traps/genetics ; Extracellular Traps/immunology ; Histones/immunology ; Humans ; Ligands ; Mitogen-Activated Protein Kinases/genetics ; Mitogen-Activated Protein Kinases/immunology ; Neutrophils/cytology ; Neutrophils/immunology ; Signal Transduction
    Chemical Substances Antigens, Neoplasm ; Chromatin ; Histones ; Ligands ; MOK protein, human (EC 2.7.11.22) ; Mitogen-Activated Protein Kinases (EC 2.7.11.24)
    Language English
    Publishing date 2021-09-20
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2606827-8
    ISSN 1664-3224 ; 1664-3224
    ISSN (online) 1664-3224
    ISSN 1664-3224
    DOI 10.3389/fimmu.2021.675315
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Physiological Stimuli Induce PAD4-Dependent, ROS-Independent NETosis, With Early and Late Events Controlled by Discrete Signaling Pathways.

    Tatsiy, Olga / McDonald, Patrick P

    Frontiers in immunology

    2018  Volume 9, Page(s) 2036

    Abstract: Neutrophils are known to extrude decondensed chromatin, thus forming NETs (neutrophil extracellular traps). These structures immobilize pathogens, thereby preventing their spreading, and are also adorned with antimicrobial molecules. NETs can also ... ...

    Abstract Neutrophils are known to extrude decondensed chromatin, thus forming NETs (neutrophil extracellular traps). These structures immobilize pathogens, thereby preventing their spreading, and are also adorned with antimicrobial molecules. NETs can also influence pathogenesis in chronic inflammation, autoimmunity, and cancer. Despite the importance of NETs, the molecular mechanisms underlying their formation, as well as the upstream signaling pathways involved, are only partially understood. Likewise, current methodological approaches to quantify NETs suffer from significant drawbacks, not the least being the inclusion of a significant non-specific signal. In this study, we used novel, fluorescent polymers that only bind extruded chromatin, allowing a specific and standardized quantification of NETosis. This allowed us to reliably rank the relative potency of various physiologic NET inducers. In neutrophils activated with such stimuli, inhibition of the Syk or PI3K pathways blocked NETosis by acting upon late events in NET formation. Inhibition of the TAK1, p38 MAPK, or MEK pathways also hindered NETosis, but by acting on early events. By contrast, inhibiting PKC, Src family kinases, or JNK failed to prevent NETosis; cycloheximide or actinomycin D were also ineffective. Expectedly, NET formation was deeply compromised following inhibition of the NADPH oxidase in PMA-activated neutrophils, but was found to be ROS-independent in response to physiological agonists. Conversely, we show for the first time in human neutrophils that selective inhibition of PAD4 potently prevents NETosis by all stimuli tested. Our data substantially extends current knowledge of the signaling pathways controlling NETosis, and reveals how they affect early or late stages of the phenomenon. In view of the involvement of NETs in several pathologies, our findings also identify molecular targets that could be exploited for therapeutic intervention.
    MeSH term(s) Cells, Cultured ; Endocytosis ; Extracellular Traps/metabolism ; Fluorescent Dyes/metabolism ; Humans ; NADPH Oxidases/metabolism ; Neutrophil Activation ; Neutrophils/physiology ; Phosphatidylinositol 3-Kinases/metabolism ; Phosphorylcholine/analogs & derivatives ; Phosphorylcholine/metabolism ; Polymethacrylic Acids/metabolism ; Protein-Arginine Deiminases/metabolism ; Reactive Oxygen Species/metabolism ; Signal Transduction ; Syk Kinase/metabolism ; p38 Mitogen-Activated Protein Kinases/metabolism
    Chemical Substances Fluorescent Dyes ; Polymethacrylic Acids ; Reactive Oxygen Species ; poly(MPC-co-MA) ; Phosphorylcholine (107-73-3) ; NADPH Oxidases (EC 1.6.3.-) ; Phosphatidylinositol 3-Kinases (EC 2.7.1.-) ; Syk Kinase (EC 2.7.10.2) ; p38 Mitogen-Activated Protein Kinases (EC 2.7.11.24) ; Protein-Arginine Deiminases (EC 3.5.3.15) ; peptidylarginine deiminase type IV (EC 3.5.3.15)
    Language English
    Publishing date 2018-09-18
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2606827-8
    ISSN 1664-3224 ; 1664-3224
    ISSN (online) 1664-3224
    ISSN 1664-3224
    DOI 10.3389/fimmu.2018.02036
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Prophylactic Vaccination and Intratumoral Boost with HER2-Expressing Oncolytic Herpes Simplex Virus Induces Robust and Persistent Immune Response against HER2-Positive Tumor Cells.

    Delwar, Zahid / Tatsiy, Olga / Chouljenko, Dmitry V / Lee, I-Fang / Liu, Guoyu / Liu, Xiaohu / Bu, Luke / Ding, Jun / Singh, Manu / Murad, Yanal M / Jia, William Wei-Guo

    Vaccines

    2023  Volume 11, Issue 12

    Abstract: The development of effective cancer vaccines remains a significant challenge due to immune tolerance and limited clinical benefits. Oncolytic herpes simplex virus type 1 (oHSV-1) has shown promise as a cancer therapy, but efficacy is often limited in ... ...

    Abstract The development of effective cancer vaccines remains a significant challenge due to immune tolerance and limited clinical benefits. Oncolytic herpes simplex virus type 1 (oHSV-1) has shown promise as a cancer therapy, but efficacy is often limited in advanced cancers. In this study, we constructed and characterized a novel oHSV-1 virus (VG22401) expressing the human epidermal growth factor receptor 2 (HER2), a transmembrane glycoprotein overexpressed in many carcinomas. VG22401 exhibited efficient replication and HER2 payload expression in both human and mouse colorectal cancer cells. Mice immunized with VG22401 showed significant binding of serum anti-HER2 antibodies to HER2-expressing tumor cells, inducing antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Furthermore, mice primed with VG22401 and intratumorally boosted with the same virus showed enhanced antitumor efficacy in a bilateral syngeneic HER2(+) tumor model, compared to HER2-null backbone virus. This effect was accompanied by the induction of anti-HER2 T cell responses. Our findings suggest that peripheral priming with HER2-expressing oHSV-1 followed by an intratumoral boost with the same virus can significantly enhance antitumor immunity and efficacy, presenting a promising strategy for cancer immunotherapy.
    Language English
    Publishing date 2023-12-02
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2703319-3
    ISSN 2076-393X
    ISSN 2076-393X
    DOI 10.3390/vaccines11121805
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Regulation of Discrete Functional Responses by Syk and Src Family Tyrosine Kinases in Human Neutrophils.

    Ear, Thornin / Tatsiy, Olga / Allard, Frédérick L / McDonald, Patrick P

    Journal of immunology research

    2017  Volume 2017, Page(s) 4347121

    Abstract: Neutrophils play a critical role in innate immunity and also influence adaptive immune responses. This occurs in good part through their production of inflammatory and immunomodulatory cytokines, in conjunction with their prolonged survival at inflamed ... ...

    Abstract Neutrophils play a critical role in innate immunity and also influence adaptive immune responses. This occurs in good part through their production of inflammatory and immunomodulatory cytokines, in conjunction with their prolonged survival at inflamed foci. While a picture of the signaling machinery underlying these neutrophil responses is now emerging, much remains to be uncovered. In this study, we report that neutrophils constitutively express various Src family isoforms (STKs), as well as Syk, and that inhibition of these protein tyrosine kinases selectively hinders inflammatory cytokine generation by acting posttranscriptionally. Accordingly, STK or Syk inhibition decreases the phosphorylation of signaling intermediates (e.g., eIF-4E, S6K, and MNK1) involved in translational control. By contrast, delayed apoptosis appears to be independent of either STKs or Syk. Our data therefore significantly extend our understanding of which neutrophil responses are governed by STKs and Syk and pinpoint some signaling intermediates that are likely involved. In view of the foremost role of neutrophils in several chronic inflammatory conditions, our findings identify potential molecular targets that could be exploited for future therapeutic intervention.
    Language English
    Publishing date 2017
    Publishing country Egypt
    Document type Journal Article
    ZDB-ID 2817541-4
    ISSN 2314-7156 ; 2314-8861
    ISSN (online) 2314-7156
    ISSN 2314-8861
    DOI 10.1155/2017/4347121
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Cytokine Production and NET Formation by Monosodium Urate-Activated Human Neutrophils Involves Early and Late Events, and Requires Upstream TAK1 and Syk.

    Tatsiy, Olga / Mayer, Thomas Z / de Carvalho Oliveira, Vanessa / Sylvain-Prévost, Stéphanie / Isabel, Marilyn / Dubois, Claire M / McDonald, Patrick P

    Frontiers in immunology

    2020  Volume 10, Page(s) 2996

    Abstract: Gout is a prevalent and incapacitating disease triggered by the deposition of monosodium urate (MSU) crystals in joints, which are also massively infiltrated by neutrophils. The interaction of the latter with MSU crystals triggers several responses, ... ...

    Abstract Gout is a prevalent and incapacitating disease triggered by the deposition of monosodium urate (MSU) crystals in joints, which are also massively infiltrated by neutrophils. The interaction of the latter with MSU crystals triggers several responses, including the generation of inflammatory mediators and of neutrophil extracellular traps (NETs). Though some of the signaling events mobilized by MSU in neutrophils have been described (e.g., Src family kinases, Syk, PKC, PI3K), the picture remains fragmentary. Likewise, the impact of these signaling events on cellular responses is incompletely understood. In this study, we examined transcriptomic changes triggered by MSU in neutrophils and their impact on the corresponding proteins, as well as the role of various signaling pathways in prominent functional responses. We report for the first time that neutrophils can secrete the monocyte chemoattractant, CCL4, in response to MSU. Accordingly, we found that transcription factors NF-κB, CREB, and C/EBP are belatedly activated by MSU crystals, and at least the former is involved in chemokine generation. Moreover, we show that MAPKs and Akt are activated by MSU in neutrophils, that they are under the control of TAK1 and Syk, and that they participate in cytokine generation and NETosis. In the latter instance, we found the phenomenon to be independent of endogenous ROS, but under the control of PAD4. We finally provide evidence that endogenous factors contribute to the belated phosphorylation of kinases and transcription factors in response to MSU. Collectively, our findings unveil potentially important therapeutic targets for gouty arthritis.
    MeSH term(s) Cytokines/genetics ; Cytokines/immunology ; Extracellular Traps/genetics ; Extracellular Traps/immunology ; Gout/genetics ; Gout/immunology ; Gout/metabolism ; Humans ; MAP Kinase Kinase Kinases/genetics ; MAP Kinase Kinase Kinases/immunology ; Neutrophil Activation ; Neutrophils/immunology ; Syk Kinase/genetics ; Syk Kinase/immunology ; Uric Acid/metabolism
    Chemical Substances Cytokines ; Uric Acid (268B43MJ25) ; Syk Kinase (EC 2.7.10.2) ; MAP Kinase Kinase Kinases (EC 2.7.11.25) ; MAP kinase kinase kinase 7 (EC 2.7.11.25)
    Language English
    Publishing date 2020-01-15
    Publishing country Switzerland
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2606827-8
    ISSN 1664-3224 ; 1664-3224
    ISSN (online) 1664-3224
    ISSN 1664-3224
    DOI 10.3389/fimmu.2019.02996
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Role of the p38 MAPK/C/EBPβ Pathway in the Regulation of Phenotype and IL-10 and IL-12 Production by Tolerogenic Bone Marrow-Derived Dendritic Cells.

    Guindi, Chantal / Cloutier, Alexandre / Gaudreau, Simon / Zerif, Echarki / McDonald, Patrick P / Tatsiy, Olga / Asselin, Claude / Dupuis, Gilles / Gris, Denis / Amrani, And Abdelaziz

    Cells

    2018  Volume 7, Issue 12

    Abstract: Dendritic cells (DCs) play a major role in innate and adaptive immunity and self-immune tolerance. Immunogenic versus tolerogenic DC functions are dictated by their levels of costimulatory molecules and their cytokine expression profile. The ... ...

    Abstract Dendritic cells (DCs) play a major role in innate and adaptive immunity and self-immune tolerance. Immunogenic versus tolerogenic DC functions are dictated by their levels of costimulatory molecules and their cytokine expression profile. The transcription factor C/EBPβ regulates the expression of several inflammatory genes in many cell types including macrophages. However, little is known regarding the role of C/EBPβ in tolerogenic versus immunogenic DCs functions. We have previously reported that bone marrow-derived DCs generated with GM-CSF (GM/DCs) acquire the signature of semi-mature tolerogenic IL-10-producing DCs as opposed to immunogenic DCs generated with GM-CSF and IL-4 (IL-4/DCs). Here, we show that tolerogenic GM/DCs exhibit higher levels of phosphorylation and enhanced DNA binding activity of C/EBPβ and CREB than immunogenic IL-4/DCs. We also show that the p38 MAPK/CREB axis and GSK3 play an important role in regulating C/EBPβ phosphorylation and DNA binding activity. Inhibition of p38 MAPK in GM/DCs resulted in a drastic decrease of C/EBPβ and CREB DNA binding activities, a reduction of their IL-10 production and an increase of their IL-12p70 production, a characteristic of immunogenic IL-4/DCs. We also present evidence that GSK3 inhibition in GM/DCs reduced C/EBPβ DNA binding activity and increased expression of costimulatory molecules in GM/DCs and their production of IL-10. Analysis of GM/DCs of C/EBPβ
    Language English
    Publishing date 2018-12-07
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2661518-6
    ISSN 2073-4409
    ISSN 2073-4409
    DOI 10.3390/cells7120256
    Database MEDical Literature Analysis and Retrieval System OnLINE

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