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Edward F. Plow - One of the best experts on this subject based on the ideXlab platform.
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Identification of pH-Regulated Antigen 1 Released froM Candida albicans as the Major Ligand for Leukocyte Integrin αMβ2
Journal of immunology (Baltimore Md. : 1950), 2007Co-Authors: Dmitry A. Soloviev, Elzbieta Pluskota, William A. Fonzi, Rafael Sentandreu, Christopher B. Forsyth, Satya P. Yadav, Edward F. PlowAbstract:Candida albicans is a coMMon opportunistic fungal pathogen and is the leading cause of invasive fungal disease in iMMunocoMproMised individuals. The induction of cell-Mediated iMMunity to C. albicans is of critical iMportance in host defense and the priMe task of cells of the innate iMMune systeM. We previously deMonstrated that the Integrin Alpha(M)beta(2) (CD11b/CD18) is the Major leukocyte receptor involved in C. albicans recognition, Mediating both adhesive and Migratory responses to the fungus. In the present study, we deMonstrate that various C. albicans strains release a protease-sensitive activity into their conditioned MediuM that supports Alpha(M)beta(2)-Mediated cell adhesion and Migration. The isolation and characterization of this protein was undertaken by two independent approaches: 1) iMMunoaffinity purification on a MAb raised to conditioned MediuM which blocked Alpha(M)beta(2)-dependent adhesion and Migration; and 2) affinity chroMatography on purified Alpha(M)beta(2). Each approach led to the isolation of the saMe protein, which was unequivocally identified as pH-regulated Ag 1 (Pra1p), based on Mass spectroMetry and aMino acid sequence analyses. C. albicans Mutant strains lacking Pra1p were unable to support leukocyte adhesion or Migration. In a neutrophil-Mediated fungal killing assay, such Mutant strains were resistant to killing and/or phagocytosis. Addition of purified Pra1p or reagents that block Alpha(M)beta(2) function prevented killing of Pra1p-expressing but not Pra1p-deficient strains of C. albicans. Together, these data indicate that Pra1p is a ligand of Alpha(M)beta(2) on C. albicans and that the soluble forM of Pra1p May assist the fungus in escaping host surveillance.
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Identity of the aMino acid residues involved in C3bi binding to the I-doMain supports a Mosaic Model to explain the broad ligand repertoire of Integrin αMβ2
Biochemistry, 2005Co-Authors: Valentin Ustinov, Edward F. PlowAbstract:Abstract Interactions between the coMpleMent degradation product C3bi and leukocyte Integrin Alpha(M)beta(2) are critical for host defense against foreign pathogens and in tuMor cell surveillance. To gain insight into the MechanisM by which the Alpha(M)I-doMain of the Integrin interacts with C3bi, detailed Mapping of the C3bi binding site was undertaken. Previous Mutagenesis studies had iMplicated five sMall structural segMents within the Alpha(M)I-doMain in recognition of this ligand. Sets of three aMino acids within the five iMplicated segMents were Mutated to the corresponding Alpha(L)I-doMain residues. Then, within the affected Mutants, single point Mutations were introduced to precisely define the requisite residues. UltiMately, H148, F150, Q204, L205, R208, T211, T213, I256, P257 were identified as being critical for C3bi binding. A synthetic peptide approach confirMed the involveMent of the specified residues with the coMplex MidsegMent, Q204-I215, in C3bi recognition. FurtherMore, the Alpha(D)I-doMain, which has a low intrinsic affinity for C3bi, acquired high affinity for the ligand when the iMplicated residues were inserted. The residues necessary to engage C3bi reside on or adjacent to the cation binding MIDAS site of the Alpha(M)I-doMain. The aMino acids involved in C3bi binding are distinct froM those involved in interaction of previously Mapped ligands with the Alpha(M)I-doMain. This divergence supports a Mosaic Model, in which different ligands engage different aMino acids to bind to Alpha(M)I-doMain, accounting for the broad recognition capacity of Integrin Alpha(M)beta(2).
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Integrin αMβ2 Orchestrates and Accelerates PlasMinogen Activation and Fibrinolysis by Neutrophils
The Journal of biological chemistry, 2004Co-Authors: Elzbieta Pluskota, Dmitry A. Soloviev, Khalil Bdeir, Douglas B. Cines, Edward F. PlowAbstract:PlasMin, the pivotal throMbolytic enzyMe, is generated on the surface of Many cell types, where urokinase receptor (uPAR)-bound urokinase (uPA) activates cell-bound plasMinogen (Plg). It has been reported that neutrophils Mediate endogenous throMbolysis involving a uPA-dependent MechanisM, and we previously deMonstrated that both uPAR and Integrin Alpha(M)beta(2) recognize uPA to control cell Migration and adhesion. In the present study, we report that the Alpha(M)beta(2) regulates neutrophil-dependent fibrinolysis. Phorbol 12-Myristate 13-acetate (PMA)-stiMulated but not resting neutrophils dissolved fibrin clots, and this activity was not only uPA- and Plg-dependent but also Alpha(M)beta(2)-dependent. Purified Alpha(M)beta(2) directly bound uPA (K(d) = 40 nM) and Plg (K(d) = 1 MicroM) in a dose-dependent and saturable Manner. In Plg activation assays, addition of purified Alpha(M)beta(2), but not a control protein, to a single chain uPA (sc-uPA)/Plg Mixture, decreased the K(M) froM 2 to 0.1 MicroM, thereby augMenting the overall reaction efficiency by 50-fold. The binding of sc-uPA to Alpha(M)beta(2) was critical for the Alpha(M)beta(2)-Mediated enhanceMent of plasMin (PlM) generation, because this effect was lost when WT-sc-uPA was replaced with a kringle-less Mutant (DeltaK-sc-uPA), which does not bind to Alpha(M)beta(2). PlM inactivation by Alpha(2)-antiplasMin was significantly delayed when PlM was preincubated with purified, soluble Alpha(M)beta(2). When Plg was added to PMA-stiMulated neutrophils, both uPA and Plg were co-iMMunoprecipitated with Alpha(M)beta(2.) Thus, asseMbly of Plg and uPA on Integrin Alpha(M)beta(2) regulates PlM activity and, thereby, plays a crucial role in neutrophil-Mediated throMbolysis.
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Delineation of the Key AMino Acids Involved in Neutrophil Inhibitory Factor Binding to the I-doMain Supports a Mosaic Model for the Capacity of Integrin αMβ2 to Recognize Multiple Ligands
The Journal of biological chemistry, 2002Co-Authors: Valentin Ustinov, Edward F. PlowAbstract:To gain insight into the MechanisM by which the Alpha(M)I-doMain of Integrin Alpha(M)beta(2) interacts with Multiple and unrelated ligands, the identity of the neutrophil inhibitory factor (NIF) recognition site was sought. A systeMatic strategy in which individual aMino acid residues within three previously iMplicated segMents were changed to those in the Alpha(L)I-doMain, which is structurally very siMilar but does not bind NIF, was iMpleMented. The capacity of the resulting Mutants, expressed as glutathione S-transferase fusion proteins, to recognize NIF was assessed. These analyses ultiMately identified Asp(149), Arg(151), Gly(207), Tyr(252), and Glu(258) as critical for NIF binding. Cation binding, a function of the Metal ion-dependent adhesion site (MIDAS) Motif, was assessed by terbiuM luMinescence to evaluate conforMational perturbations induced by the Mutations. All five Mutants bound terbiuM with unaltered affinities. When the five residues were inserted into the Alpha(L)I-doMain, the chiMera bound NIF with high affinity. Another ligand of Alpha(M)beta(2), C3bi, which is known to use the saMe segMents of the Alpha(M)I-doMain in engaging the receptor, failed to bind to the chiMeric Alpha(L)I-doMain. Thus, the Alpha(M)I-doMain appears to present a Mosaic of exposed aMino acids within surface loops on its MIDAS face, and different ligands interact with different residues to attain high affinity binding.
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The structural Motif glycine 190-valine 202 of the fibrinogen gaMMa chain interacts with CD11b/CD18 Integrin (Alpha M beta 2, Mac-1) and proMotes leukocyte adhesion.
The Journal of biological chemistry, 1993Co-Authors: Dario C. Altieri, Janet Plescia, Edward F. PlowAbstract:The leukocyte-restricted Integrin CD11b/CD18 (Alpha M beta 2, Mac-1) is a receptor for fibrinogen on stiMulated Monocytes and neutrophils. At variance with platelet Alpha IIb beta 3 or endothelial cell Alpha v beta 3 Integrins, CD11b/CD18 interacts with a approxiMately 30-kDa plasMic fragMent D (D30) of fibrinogen that lacks the Arg-Gly-Asp sequences in the A Alpha chain and the carboxyl terMinus of the gaMMa chain. Using epitope-Mapped antibodies and synthetic peptidyl MiMicry, we have now identified a unique linear sequence in fibrinogen that Mediates ligand binding to CD11b/CD18. Anti-fibrinogen antibodies directed to the gaMMa chain region 95-264 inhibited 125I-fibrinogen or 125I-D30 binding to cheMoattractant-stiMulated neutrophils or Monocytic THP-1 cells in a dose-dependent fashion. Partially overlapping synthetic peptides reproducing this gaMMa chain region were tested for their ability to inhibit fibrinogen binding to leukocytes. A synthetic peptide designated P1, duplicating gaMMa chain Gly190-Val202, inhibited 125I-fibrinogen binding to stiMulated neutrophils or THP-1 cells and blocked adhesion of these cells to iMMobilized fibrinogen in a dose-dependent fashion. Increasing concentrations of P1 inhibited 125I-fibrinogen binding to isolated CD11b/CD18 in a cell-free systeM. Consistent with genuine peptidyl MiMicry, 125I-P1 bound saturably to THP-1 cells in a reaction inhibited by Molar excess of unlabeled peptide, fibrinogen, or D30. Finally, iMMobilized P1 effectively supported adhesion of THP-1 cells in a CD11b/CD18-dependent Manner. These data suggest that the fibrinogen gaMMa chain region Gly190-Val202 functions as a MiniMal recognition sequence for the leukocyte Integrin CD11b/CD18. Given the participation of fibrinogen:leukocyte interaction in inflaMMation and atherogenesis, antagonists based on this unique structural Motif would effectively interfere with aberrant leukocyte adhesion MechanisMs without affecting Arg-Gly-Asp-directed vascular Integrins.
Eric J Brown - One of the best experts on this subject based on the ideXlab platform.
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coMpleMent receptor 3 cr3 Mac 1 Integrin Alpha M beta 2 cd11b cd18 is required for tyrosine phosphorylation of paxillin in adherent and nonadherent neutrophils
Journal of Cell Biology, 1994Co-Authors: I L Graham, Donald C Anderson, V M Holers, Eric J BrownAbstract:Expression of the leukocyte (beta 2) Integrins is required for Many functions of activated neutrophils (PMN), even when there is no recognized ligand for any beta 2 Integrin. To investigate the hypothesis that beta 2 Integrins May be involved in a signal transduction pathway related to cytoskeletal reorganization, we exaMined whether beta 2 Integrins have a role in tyrosine phosphorylation of the cytoskeletal protein paxillin. TreatMent of PMN in suspension with phorbol esters, f-Met-Leu-Phe, and TNF-Alpha resulted in paxillin tyrosine phosphorylation. However, treatMent of beta 2-deficient (LAD) PMN failed to induce paxillin tyrosine phosphorylation. NorMal PMN phosphorylated paxillin in response to adhesion to iMMune coMplexes, while the LAD PMN did not. Adhesion of phorbol ester activated-LAD PMN to the extracellular Matrix proteins fibronectin, laMinin, and vitronectin failed to induce paxillin tyrosine phosphorylation. TreatMent of activated norMal PMN with MAb directed against the beta 2 Integrin Alpha chains deMonstrated that CR3 (Alpha M beta 2) was required for paxillin phosphorylation. Transfection of the cell line K562 with CR3 confirMed that CR3 ligation resulted in paxillin tyrosine phosphorylation. As a control, K562 transfected with CR2 (CD21) which bound equally avidly to the saMe coMpleMent C3-derived ligand (C3bi) as the CR3 transfectants, showed no enhanced tyrosine phosphorylation of paxillin upon receptor ligation. While both CR2 and CR3 transfectants showed efficient adhesion to a C3bi-coated surface, only the CR3 transfectants spread during adhesion and phosphorylated paxillin. Together these data deMonstrate that CR3 is required for paxillin phosphorylation during activation of both adherent and nonadherent PMN. Even PMN activated in suspension or by adhesion to iMMune coMplexes, when no CR3 ligand is apparent, still require CR3 for a signal transduction pathway leading to paxillin tyrosine phosphorylation. This pathway is likely to be iMportant for PMN function in inflaMMation and host defense.
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CoMpleMent receptor 3 (CR3, Mac-1, Integrin Alpha M beta 2, CD11b/CD18) is required for tyrosine phosphorylation of paxillin in adherent and nonadherent neutrophils.
The Journal of cell biology, 1994Co-Authors: I L Graham, Donald C Anderson, V M Holers, Eric J BrownAbstract:Expression of the leukocyte (beta 2) Integrins is required for Many functions of activated neutrophils (PMN), even when there is no recognized ligand for any beta 2 Integrin. To investigate the hypothesis that beta 2 Integrins May be involved in a signal transduction pathway related to cytoskeletal reorganization, we exaMined whether beta 2 Integrins have a role in tyrosine phosphorylation of the cytoskeletal protein paxillin. TreatMent of PMN in suspension with phorbol esters, f-Met-Leu-Phe, and TNF-Alpha resulted in paxillin tyrosine phosphorylation. However, treatMent of beta 2-deficient (LAD) PMN failed to induce paxillin tyrosine phosphorylation. NorMal PMN phosphorylated paxillin in response to adhesion to iMMune coMplexes, while the LAD PMN did not. Adhesion of phorbol ester activated-LAD PMN to the extracellular Matrix proteins fibronectin, laMinin, and vitronectin failed to induce paxillin tyrosine phosphorylation. TreatMent of activated norMal PMN with MAb directed against the beta 2 Integrin Alpha chains deMonstrated that CR3 (Alpha M beta 2) was required for paxillin phosphorylation. Transfection of the cell line K562 with CR3 confirMed that CR3 ligation resulted in paxillin tyrosine phosphorylation. As a control, K562 transfected with CR2 (CD21) which bound equally avidly to the saMe coMpleMent C3-derived ligand (C3bi) as the CR3 transfectants, showed no enhanced tyrosine phosphorylation of paxillin upon receptor ligation. While both CR2 and CR3 transfectants showed efficient adhesion to a C3bi-coated surface, only the CR3 transfectants spread during adhesion and phosphorylated paxillin. Together these data deMonstrate that CR3 is required for paxillin phosphorylation during activation of both adherent and nonadherent PMN. Even PMN activated in suspension or by adhesion to iMMune coMplexes, when no CR3 ligand is apparent, still require CR3 for a signal transduction pathway leading to paxillin tyrosine phosphorylation. This pathway is likely to be iMportant for PMN function in inflaMMation and host defense.
José E. Manautou - One of the best experts on this subject based on the ideXlab platform.
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Enhanced hepatotoxicity by acetaMinophen in Vanin-1 knockout Mice is associated with deficient proliferative and iMMune responses
Biochimica et Biophysica Acta - Molecular Basis of Disease, 2016Co-Authors: Daniel W. Ferreira, Michael Goedken, Samuel Rommelaere, Lionel Chasson, Franck Galland, Philippe Naquet, José E. ManautouAbstract:Background and aiMs: PretreatMent with clofibrate, a peroxisoMe proliferator-activated receptor Alpha (PPARa) agonist, protects Mice froM acetaMinophen (APAP) injury. Protection is not due to alterations in APAP MetabolisM and is dependent on PPARa expression. Gene array analysis revealed that Mice receiving clofibrate have enhanced hepatic Vanin-1 (Vnn1) gene expression, a response that is also PPARa dependent. Methods: We exaMined the role of Vnn1 by coMparing the responses of Vnn1 knockout and wild-type Mice following APAP hepatotoxicity. APAP MetabolisM, hepatotoxicity, and coMpensatory hepatocyte proliferation and iMMune responses were assessed. Results: Vnn1 knockout Mice are More susceptible to APAP hepatotoxicity despite no differences in hepatic glutathione content, gene expression of APAP Metabolizing enzyMes, or hepatic capacity to bioactivate or detoxify APAP ex vivo. Together, these data strongly suggest that the susceptibility of Vnn1 knockout Mice is not due to differences in APAP MetabolisM. IMMunocheMistry revealed a lack of proliferating cell nuclear antigen positive hepatocytes and F4/80-positive Macrophages in and around areas of centrilobular necrosis in APAP-treated Vnn1 knockouts. Hepatic gene induction of pro-inflaMMatory cytokines was either significantly reduced or coMpletely blunted in these Mice. This was correlated with a reduction in early recruitMent of cells positive for granulocyte differentiation antigen 1 or Integrin Alpha M. Heightened toxicity was also observed in CCl4 and ConA hepatitis Models in the absence of Vnn1. Conclusions: These results indicate that Mice lacking Vnn1 have deficiencies in coMpensatory repair and iMMune responses following toxic APAP exposure and that these MechanisMs May contribute to the enhanced hepatotoxicity seen. (C) 2016 Elsevier B.V. All rights reserved.
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Enhanced hepatotoxicity by acetaMinophen in Vanin-1 knockout Mice is associated with deficient proliferative and iMMune responses.
Biochimica et biophysica acta, 2016Co-Authors: Daniel W. Ferreira, Michael Goedken, Samuel Rommelaere, Lionel Chasson, Franck Galland, Philippe Naquet, José E. ManautouAbstract:Abstract Background and aiMs PretreatMent with clofibrate, a peroxisoMe proliferator-activated receptor Alpha (PPARa) agonist, protects Mice froM acetaMinophen (APAP) injury. Protection is not due to alterations in APAP MetabolisM and is dependent on PPARa expression. Gene array analysis revealed that Mice receiving clofibrate have enhanced hepatic Vanin-1 (Vnn1) gene expression, a response that is also PPARa dependent. Methods We exaMined the role of Vnn1 by coMparing the responses of Vnn1 knockout and wild-type Mice following APAP hepatotoxicity. APAP MetabolisM, hepatotoxicity, and coMpensatory hepatocyte proliferation and iMMune responses were assessed. Results Vnn1 knockout Mice are More susceptible to APAP hepatotoxicity despite no differences in hepatic glutathione content, gene expression of APAP Metabolizing enzyMes, or hepatic capacity to bioactivate or detoxify APAP ex vivo. Together, these data strongly suggest that the susceptibility of Vnn1 knockout Mice is not due to differences in APAP MetabolisM. IMMunocheMistry revealed a lack of proliferating cell nuclear antigen-positive hepatocytes and F4/80-positive Macrophages in and around areas of centrilobular necrosis in APAP-treated Vnn1 knockouts. Hepatic gene induction of pro-inflaMMatory cytokines was either significantly reduced or coMpletely blunted in these Mice. This was correlated with a reduction in early recruitMent of cells positive for granulocyte differentiation antigen 1 or Integrin Alpha M. Heightened toxicity was also observed in CCl4 and ConA hepatitis Models in the absence of Vnn1. Conclusions These results indicate that Mice lacking Vnn1 have deficiencies in coMpensatory repair and iMMune responses following toxic APAP exposure and that these MechanisMs May contribute to the enhanced hepatotoxicity seen.
I L Graham - One of the best experts on this subject based on the ideXlab platform.
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coMpleMent receptor 3 cr3 Mac 1 Integrin Alpha M beta 2 cd11b cd18 is required for tyrosine phosphorylation of paxillin in adherent and nonadherent neutrophils
Journal of Cell Biology, 1994Co-Authors: I L Graham, Donald C Anderson, V M Holers, Eric J BrownAbstract:Expression of the leukocyte (beta 2) Integrins is required for Many functions of activated neutrophils (PMN), even when there is no recognized ligand for any beta 2 Integrin. To investigate the hypothesis that beta 2 Integrins May be involved in a signal transduction pathway related to cytoskeletal reorganization, we exaMined whether beta 2 Integrins have a role in tyrosine phosphorylation of the cytoskeletal protein paxillin. TreatMent of PMN in suspension with phorbol esters, f-Met-Leu-Phe, and TNF-Alpha resulted in paxillin tyrosine phosphorylation. However, treatMent of beta 2-deficient (LAD) PMN failed to induce paxillin tyrosine phosphorylation. NorMal PMN phosphorylated paxillin in response to adhesion to iMMune coMplexes, while the LAD PMN did not. Adhesion of phorbol ester activated-LAD PMN to the extracellular Matrix proteins fibronectin, laMinin, and vitronectin failed to induce paxillin tyrosine phosphorylation. TreatMent of activated norMal PMN with MAb directed against the beta 2 Integrin Alpha chains deMonstrated that CR3 (Alpha M beta 2) was required for paxillin phosphorylation. Transfection of the cell line K562 with CR3 confirMed that CR3 ligation resulted in paxillin tyrosine phosphorylation. As a control, K562 transfected with CR2 (CD21) which bound equally avidly to the saMe coMpleMent C3-derived ligand (C3bi) as the CR3 transfectants, showed no enhanced tyrosine phosphorylation of paxillin upon receptor ligation. While both CR2 and CR3 transfectants showed efficient adhesion to a C3bi-coated surface, only the CR3 transfectants spread during adhesion and phosphorylated paxillin. Together these data deMonstrate that CR3 is required for paxillin phosphorylation during activation of both adherent and nonadherent PMN. Even PMN activated in suspension or by adhesion to iMMune coMplexes, when no CR3 ligand is apparent, still require CR3 for a signal transduction pathway leading to paxillin tyrosine phosphorylation. This pathway is likely to be iMportant for PMN function in inflaMMation and host defense.
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CoMpleMent receptor 3 (CR3, Mac-1, Integrin Alpha M beta 2, CD11b/CD18) is required for tyrosine phosphorylation of paxillin in adherent and nonadherent neutrophils.
The Journal of cell biology, 1994Co-Authors: I L Graham, Donald C Anderson, V M Holers, Eric J BrownAbstract:Expression of the leukocyte (beta 2) Integrins is required for Many functions of activated neutrophils (PMN), even when there is no recognized ligand for any beta 2 Integrin. To investigate the hypothesis that beta 2 Integrins May be involved in a signal transduction pathway related to cytoskeletal reorganization, we exaMined whether beta 2 Integrins have a role in tyrosine phosphorylation of the cytoskeletal protein paxillin. TreatMent of PMN in suspension with phorbol esters, f-Met-Leu-Phe, and TNF-Alpha resulted in paxillin tyrosine phosphorylation. However, treatMent of beta 2-deficient (LAD) PMN failed to induce paxillin tyrosine phosphorylation. NorMal PMN phosphorylated paxillin in response to adhesion to iMMune coMplexes, while the LAD PMN did not. Adhesion of phorbol ester activated-LAD PMN to the extracellular Matrix proteins fibronectin, laMinin, and vitronectin failed to induce paxillin tyrosine phosphorylation. TreatMent of activated norMal PMN with MAb directed against the beta 2 Integrin Alpha chains deMonstrated that CR3 (Alpha M beta 2) was required for paxillin phosphorylation. Transfection of the cell line K562 with CR3 confirMed that CR3 ligation resulted in paxillin tyrosine phosphorylation. As a control, K562 transfected with CR2 (CD21) which bound equally avidly to the saMe coMpleMent C3-derived ligand (C3bi) as the CR3 transfectants, showed no enhanced tyrosine phosphorylation of paxillin upon receptor ligation. While both CR2 and CR3 transfectants showed efficient adhesion to a C3bi-coated surface, only the CR3 transfectants spread during adhesion and phosphorylated paxillin. Together these data deMonstrate that CR3 is required for paxillin phosphorylation during activation of both adherent and nonadherent PMN. Even PMN activated in suspension or by adhesion to iMMune coMplexes, when no CR3 ligand is apparent, still require CR3 for a signal transduction pathway leading to paxillin tyrosine phosphorylation. This pathway is likely to be iMportant for PMN function in inflaMMation and host defense.
Daniel W. Ferreira - One of the best experts on this subject based on the ideXlab platform.
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Enhanced hepatotoxicity by acetaMinophen in Vanin-1 knockout Mice is associated with deficient proliferative and iMMune responses
Biochimica et Biophysica Acta - Molecular Basis of Disease, 2016Co-Authors: Daniel W. Ferreira, Michael Goedken, Samuel Rommelaere, Lionel Chasson, Franck Galland, Philippe Naquet, José E. ManautouAbstract:Background and aiMs: PretreatMent with clofibrate, a peroxisoMe proliferator-activated receptor Alpha (PPARa) agonist, protects Mice froM acetaMinophen (APAP) injury. Protection is not due to alterations in APAP MetabolisM and is dependent on PPARa expression. Gene array analysis revealed that Mice receiving clofibrate have enhanced hepatic Vanin-1 (Vnn1) gene expression, a response that is also PPARa dependent. Methods: We exaMined the role of Vnn1 by coMparing the responses of Vnn1 knockout and wild-type Mice following APAP hepatotoxicity. APAP MetabolisM, hepatotoxicity, and coMpensatory hepatocyte proliferation and iMMune responses were assessed. Results: Vnn1 knockout Mice are More susceptible to APAP hepatotoxicity despite no differences in hepatic glutathione content, gene expression of APAP Metabolizing enzyMes, or hepatic capacity to bioactivate or detoxify APAP ex vivo. Together, these data strongly suggest that the susceptibility of Vnn1 knockout Mice is not due to differences in APAP MetabolisM. IMMunocheMistry revealed a lack of proliferating cell nuclear antigen positive hepatocytes and F4/80-positive Macrophages in and around areas of centrilobular necrosis in APAP-treated Vnn1 knockouts. Hepatic gene induction of pro-inflaMMatory cytokines was either significantly reduced or coMpletely blunted in these Mice. This was correlated with a reduction in early recruitMent of cells positive for granulocyte differentiation antigen 1 or Integrin Alpha M. Heightened toxicity was also observed in CCl4 and ConA hepatitis Models in the absence of Vnn1. Conclusions: These results indicate that Mice lacking Vnn1 have deficiencies in coMpensatory repair and iMMune responses following toxic APAP exposure and that these MechanisMs May contribute to the enhanced hepatotoxicity seen. (C) 2016 Elsevier B.V. All rights reserved.
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Enhanced hepatotoxicity by acetaMinophen in Vanin-1 knockout Mice is associated with deficient proliferative and iMMune responses.
Biochimica et biophysica acta, 2016Co-Authors: Daniel W. Ferreira, Michael Goedken, Samuel Rommelaere, Lionel Chasson, Franck Galland, Philippe Naquet, José E. ManautouAbstract:Abstract Background and aiMs PretreatMent with clofibrate, a peroxisoMe proliferator-activated receptor Alpha (PPARa) agonist, protects Mice froM acetaMinophen (APAP) injury. Protection is not due to alterations in APAP MetabolisM and is dependent on PPARa expression. Gene array analysis revealed that Mice receiving clofibrate have enhanced hepatic Vanin-1 (Vnn1) gene expression, a response that is also PPARa dependent. Methods We exaMined the role of Vnn1 by coMparing the responses of Vnn1 knockout and wild-type Mice following APAP hepatotoxicity. APAP MetabolisM, hepatotoxicity, and coMpensatory hepatocyte proliferation and iMMune responses were assessed. Results Vnn1 knockout Mice are More susceptible to APAP hepatotoxicity despite no differences in hepatic glutathione content, gene expression of APAP Metabolizing enzyMes, or hepatic capacity to bioactivate or detoxify APAP ex vivo. Together, these data strongly suggest that the susceptibility of Vnn1 knockout Mice is not due to differences in APAP MetabolisM. IMMunocheMistry revealed a lack of proliferating cell nuclear antigen-positive hepatocytes and F4/80-positive Macrophages in and around areas of centrilobular necrosis in APAP-treated Vnn1 knockouts. Hepatic gene induction of pro-inflaMMatory cytokines was either significantly reduced or coMpletely blunted in these Mice. This was correlated with a reduction in early recruitMent of cells positive for granulocyte differentiation antigen 1 or Integrin Alpha M. Heightened toxicity was also observed in CCl4 and ConA hepatitis Models in the absence of Vnn1. Conclusions These results indicate that Mice lacking Vnn1 have deficiencies in coMpensatory repair and iMMune responses following toxic APAP exposure and that these MechanisMs May contribute to the enhanced hepatotoxicity seen.