| 1. |
- Ding, Zhiyi, et al.
(författare)
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Actin-related protein 2/3 complex regulates neutrophil extracellular trap expulsion and lung damage in abdominal sepsis
- 2022
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Ingår i: American Journal of Physiology - Lung Cellular and Molecular Physiology. - 1040-0605. ; 322:5, s. 662-672
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophil extracellular trap (NET) formation is a key feature in sepsis. The aim of the present study was to examine the role of the actin cytoskeleton in regulating the expulsion of NETs. Actin-related protein 2/3 (Arp 2/3) complex is an important regulator of F-actin polymerization. Coincubation with CK666, a specific Arp 2/3 inhibitor, decreased 12-phorbol 13-myristate acetate-induced NET formation in vitro. CK666 not only abolished F-actin polymerization but also caused intracellular retention of NETs. Inhibition of Arp 2/3 reduced NET formation on circulating neutrophils and in the bronchoalveolar space in mice undergoing cecal ligation and puncture (CLP). Notably, treatment with CK666 attenuated CLP-induced neutrophil recruitment, edema formation, and tissue damage in the lungs. Moreover, Arp 2/3 inhibition decreased levels of C-X-C motif chemokine ligand 1 (CXCL-1) and interleukin-6 in the lung and plasma of septic animals. Taken together, this study shows that expulsion of NETs is regulated by the actin cytoskeleton and that inhibition of Arp 2/3-dependent F-actin polymerization not only decreases NET formation but also protects against pathological inflammation and tissue damage in septic lung injury. Thus, we suggest that targeting NET release is a novel and useful way to ameliorate lung damage in abdominal sepsis.
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| 2. |
- Ding, Zhiyi
(författare)
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Neutrophil and endothelial cell-mediated inflammation in abdominal sepsis
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sepsis is defined as a life-threatening condition caused by a dysregulated host response to infection. Neutrophils are themost abundant innate immune cells of the body and play a key role in septic pathogenesis. During sepsis activatedneutrophils release web-like traps decorated with various cellular proteins known as neutrophil extracellular traps(NET). The primary task of NET and NET-associated proteins are to kill pathogens; however, excessive accumulationof NET is known to cause tissue damage. Endothelial cells are important for regulating vascular permeability andbarrier functions; however, during sepsis endothelial cells get activated and contribute to tissue damage andorgan failure. The four original studies included in this thesis aimed to investigate new mechanisms involved information of NET, lung injury and pulmonary endothelial cell activation in abdominal sepsis. In study I, we havefound that c-Abl kinase regulate NET formation through ROS signaling pathway. Blocking of c-Abl kinase notonly inhibited NET formation but also reduced inflammation and tissue damage in sepsis. In study II, weinvestigated the role of actin-related protein 2/3 complex (Arp2/3 complex) and found that it regulates neutrophiltrap expulsion both in vivo and in vitro. Inhibition of Arp2/3 complex not only reduced the neutrophil infiltration inbronchoalveolar space, but also alleviated lung damage in abdominal sepsis. In study III, we investigated the roleof S100A9, a pro-inflammatory alarmin, in regulating inflammation and tissue damage in abdominal sepsis.Inhibition of S100A9 by a specific inhibitor, ABR-238901, decreased sepsis-induced neutrophil activation,cytokine formation as well as damage to the lung tissue. In study IV, we examined global transcriptomic changesin a subgroup of lung endothelial cells during sepsis. We found that sepsis caused transcriptomic changes ofgenes related to regulation of coagulation, vascular permeability as well as wound healing and lipid metabolic incapillary endothelial cells. In contrast, postcapillary venules were found to be more enriched with genes related tochemotaxis, cell-cell adhesion of integrins, chemokine biosynthesis, regulation of actin polymerization andneutrophil homeostasis after sepsis. Together, these results demonstrated that targeting c-Abl, Arp2/3 complex,S100A9 or endothelial functions could be useful targets to ameliorate neutrophil mediated tissue injury in sepsis.
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| 3. |
- Ding, Zhiyi, et al.
(författare)
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Targeting s100a9 reduces neutrophil recruitment, inflammation and lung damage in abdominal sepsis
- 2021
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 22:23
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Tidskriftsartikel (refereegranskat)abstract
- S100A9, a pro-inflammatory alarmin, is up-regulated in inflamed tissues. However, the role of S100A9 in regulating neutrophil activation, inflammation and lung damage in sepsis is not known. Herein, we hypothesized that blocking S100A9 function may attenuate neutrophil recruitment in septic lung injury. Male C57BL/6 mice were pretreated with the S100A9 inhibitor ABR-238901 (10 mg/kg), prior to cercal ligation and puncture (CLP). Bronchoalveolar lavage fluid (BALF) and lung tissue were harvested for analysis of neutrophil infiltration as well as edema and CXC chemokine production. Blood was collected for analysis of membrane-activated complex-1 (Mac-1) expression on neutrophils as well as CXC chemokines and IL-6 in plasma. Induction of CLP mark-edly increased plasma levels of S100A9. ABR-238901 decreased CLP-induced neutrophil infiltration and edema formation in the lung. In addition, inhibition of S100A9 decreased the CLP-induced up-regulation of Mac-1 on neutrophils. Administration of ABR-238901 also inhibited the CLP-induced increase of CXCL-1, CXCL-2 and IL-6 in plasma and lungs. Our results suggest that S100A9 promotes neutrophil activation and pulmonary accumulation in sepsis. Targeting S100A9 function decreased formation of CXC chemokines in circulation and lungs and attenuated sepsis-induced lung damage. These novel findings suggest that S1000A9 plays an important pro-inflammatory role in sepsis and could be a useful target to protect against the excessive inflammation and lung damage associated with the disease.
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| 4. |
- Du, Feifei, et al.
(författare)
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E3 Ubiquitin Ligase Midline 1 Regulates Endothelial Cell ICAM-1 Expression and Neutrophil Adhesion in Abdominal Sepsis
- 2023
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Septic lung damage is associated with endothelial cell and neutrophil activation. This study examines the role of the E3 ubiquitin ligase midline 1 (Mid1) in abdominal sepsis. Mid1 expression was increased in endothelial cells derived from post-capillary venules in septic mice and TNF-α challenge increased Mid1 levels in endothelial cells in vitro. The siRNA-mediated knockdown of Mid1 decreased TNF-α-induced upregulation of ICAM-1 and neutrophil adhesion to endothelial cells. Moreover, Mid1 silencing reduced leukocyte adhesion in post-capillary venules in septic lungs in vivo. The silencing of Mid1 not only decreased Mid1 expression but also attenuated expression of ICAM-1 in lungs from septic mice. Lastly, TNF-α stimulation decreased PP2Ac levels in endothelial cells in vitro, which was reversed in endothelial cells pretreated with siRNA directed against Mid1. Thus, our novel data show that Mid1 is an important regulator of ICAM-1 expression and neutrophil adhesion in vitro and septic lung injury in vivo. A possible target of Mid1 is PP2Ac in endothelial cells. Targeting the Mid1-PP2Ac axis may be a useful way to reduce pathological lung inflammation in abdominal sepsis.
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| 5. |
- Du, Feifei, et al.
(författare)
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Microvascular Mechanisms of Polyphosphate-Induced Neutrophil-Endothelial Cell Interactions in vivo
- 2019
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Ingår i: European Surgical Research. - : S. Karger AG. - 0014-312X .- 1421-9921. ; 60:1-2, s. 53-62
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Tidskriftsartikel (refereegranskat)abstract
- Background: Polyphosphates (PolyPs) have been reported to exert pro-inflammatory effects. However, the molecular mechanisms regulating PolyP-provoked tissue accumulation of leukocytes are not known. The aim of the present investigation was to determine the role of specific adhesion molecules in PolyP-mediated leukocyte recruitment. Methods: PolyPs and TNF-α were intrascrotally administered, and anti-P-selectin, anti-E-selectin, anti-P-selectin glycoprotein ligand-1 (PSGL-1), anti-membrane-activated complex-1 (Mac-1), anti-lymphocyte function antigen-1 (LFA-1), and neutrophil depletion antibodies were injected intravenously or intraperitoneally. Intravital microscopy of the mouse cremaster microcirculation was used to examine leukocyte-endothelium interactions and recruitment in vivo. Results: Intrascrotal injection of PolyPs increased leukocyte accumulation. Depletion of neutrophils abolished PolyP-induced leukocyte-endothelium interactions, indicating that neutrophils were the main leukocyte subtype responding to PolyP challenge. Immunoneutralization of P-selectin and PSGL-1 abolished PolyP-provoked neutrophil rolling, adhesion, and emigration. Moreover, immunoneutralization of Mac-1 and LFA-1 had no impact on neutrophil rolling but markedly reduced neutrophil adhesion and emigration evoked by PolyPs. Conclusion: These results suggest that P-selectin and PSGL-1 exert important roles in PolyP-induced inflammatory cell recruitment by mediating neutrophil rolling. In addition, our data show that Mac-1 and LFA-1 are necessary for supporting PolyP-triggered firm adhesion of neutrophils to microvascular endothelium. These novel findings define specific molecules as potential targets for pharmacological intervention in PolyP-dependent inflammatory diseases. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
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| 6. |
- Du, Feifei, et al.
(författare)
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S100A9 induces reactive oxygen species-dependent formation of neutrophil extracellular traps in abdominal sepsis
- 2022
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 421:2
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Tidskriftsartikel (refereegranskat)abstract
- Recent evidence suggests that targeting S100A9 reduces pathological inflammation in abdominal sepsis. Herein, we investigated the role of S100A9 in neutrophil extracellular trap (NET) formation in septic lung damage. NETs were detected by electron microscopy in the lung and by confocal microscopy in vitro. Stimulation of isolated mouse bone marrow-derived neutrophils with S100A9 triggered formation of NETs. Blocking TLR4 and RAGE reduced S100A9-induced generation of NETs and DNA-histone complexes. Moreover, S100A9 challenge increased generation of reactive oxygen species (ROS) in bone marrow neutrophils. Co-incubation with the NADPH oxidase inhibitor not only decreased ROS formation but also attenuated induction of DNA-histone complexes in S100A9-stimulated neutrophils. Abdominal sepsis was induced by cecal ligation and puncture (CLP) in male C57BL/6 mice. Administration of the S100A9 inhibitor ABR-238901 decreased CLP-induced formation of NETs in lungs and DNA-histone complexes in plasma. In addition, transmission electron microscopy revealed that S100A9 was abundantly expressed on NETs in the lungs in CLP mice. By use of intravital microscopy, we found that local injection of NETs increased leukocyte adhesion and migration in the mouse cremaster muscle microvasculature. Notably, treatment with ABR-238901 attenuated NET-induced leukocyte adhesion and extravasation in the cremaster muscle, suggesting that NET-associated S100A9 promotes leukocyte recruitment in vivo. Taken together, these novel findings suggest that S100A9 triggers ROS-dependent formation of NETs via TLR4 and RAGE signaling in neutrophils. Moreover, S100A9 regulates both formation of NETs and NET-induced leukocyte recruitment in vivo. Thus, targeting S100A9 might be useful to ameliorate lung damage in abdominal sepsis.
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| 7. |
- Hawez, Avin, et al.
(författare)
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c-Abl kinase regulates neutrophil extracellular trap formation and lung injury in abdominal sepsis
- 2022
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Ingår i: Laboratory Investigation. - : Elsevier BV. - 0023-6837. ; 102:3, s. 263-271
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Tidskriftsartikel (refereegranskat)abstract
- Sepsis is associated with exaggerated neutrophil responses although mechanisms remain elusive. The aim of this study was to investigate the role of c-Abelson (c-Abl) kinase in neutrophil extracellular trap (NET) formation and inflammation in septic lung injury. Abdominal sepsis was induced by cecal ligation and puncture (CLP). NETs were detected by electron microscopy in the lung and by confocal microscopy in vitro. Plasma levels of DNA-histone complexes, interleukin-6 (IL-6) and CXC chemokines were quantified. CLP-induced enhanced phosphorylation of c-Abl kinase in circulating neutrophils. Administration of the c-Abl kinase inhibitor GZD824 not only abolished activation of c-Abl kinase in neutrophils but also reduced NET formation in the lung and plasma levels of DNA-histone complexes in CLP mice. Moreover, inhibition of c-Abl kinase decreased CLP-induced lung edema and injury. Administration of GDZ824 reduced CLP-induced increases in the number of alveolar neutrophils. Inhibition of c-Abl kinase also markedly attenuated levels of CXC chemokines in the lung and plasma as well as IL-6 levels in the plasma of septic animals. Taken together, this study demonstrates that c-Abl kinase is a potent regulator of NET formation and we conclude that c-Abl kinase might be a useful target to ameliorate lung damage in abdominal sepsis.
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| 8. |
- Rahman, Milladur, et al.
(författare)
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Transcriptomic Analysis Reveals Differential Expression of Genes between Lung Capillary and Post Capillary Venules in Abdominal Sepsis
- 2021
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 22:19, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- Lung endothelial cell dysfunction plays a central role in septic-induced lung injury. We hypothesized that endothelial cell subsets, capillary endothelial cells (capEC) and post capillary venules (PCV), might play different roles in regulating important pathophysiology in sepsis. In order to reveal global transcriptomic changes in endothelial cell subsets during sepsis, we induced sepsis in C57BL/6 mice by cecal ligation and puncture (CLP). We confirmed that CLP induced systemic and lung inflammation in our model. Endothelial cells (ECs) from lung capillary and PCV were isolated by cell sorting and transcriptomic changes were analyzed by bioinformatic tools. Our analysis revealed that lung capEC are transcriptionally different than PCV. Comparison of top differentially expressed genes (DEGs) of capEC and PCV revealed that capEC responses are different than PCV during sepsis. It was found that capEC are more enriched with genes related to regulation of coagulation, vascular permeability, wound healing and lipid metabolic processes after sepsis. In contrast, PCV are more enriched with genes related to chemotaxis, cell–cell adhesion by integrins, chemokine biosynthesis, regulation of actin filament process and neutrophil homeostasis after sepsis. In addition, we predicted some transcription factor targets that regulate a significant number of DEGs in sepsis. We proposed that targeting certain DEGs or transcriptional factors would be useful in protecting against sepsis-induced lung damage
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