INTERACTION OF CD44 AND HYALURONAN IS THE DOMINANT MECHANISM FOR NEUTROPHIL ADHESION IN INFLAMED LIVER SINUSOIDS

2008 ◽  
Vol 31 (4) ◽  
pp. 16
Author(s):  
Braedon McDonald ◽  
Erin F McAvoy ◽  
Florence Lam ◽  
Varinder Gill ◽  
Paul Kubes
Keyword(s):  
Adhesion Molecules ◽  
Intravital Microscopy ◽  
Inflammatory Responses ◽  
Flow Chamber ◽  
Neutrophil Recruitment ◽  
Neutrophil Adhesion ◽  
Antibody Technique ◽  
Liver Sinusoids

Background: Previous studies have been unable to identify adhesion molecules that mediate neutrophil recruitment within the liver sinusoids. We hypothesise that involved adhesion molecules may represent novel therapeutic targets for combating pathologic liver inflammation. Methods: Candidate adhesion molecules were identified using a novel in vivo biopanning approach (dual radiolabelled antibody technique) to quantify endothelial expression levels within the liver compared to other organs. Spinning disk intravital microscopy demonstrated the localization of adhesion molecule expression withinthe liver microvasculature. Using knockout mice, bone marrow chimeric mice, and blocking antibodies, candidate adhesion molecules were systematically investigated for a role in neutrophil recruitment in the liver sinusoids of endotoxemic mice using intravital microscopy and in vitro flow chamber assays. Results: Hyaluronan was identified as disproportionately expressed in the liver versus other organs, and hyaluronan expression was restricted to liver sinusoids. Blocking CD44-hyaluronan interactions reduced neutrophil adhesion in the sinusoids of endotoxemic mice, but had no effect on neutrophil rolling or adhesion in post-sinusoidal venules. Neutrophil but not endothelial CD44 was required for adhesionin sinusoids. Surprisingly, neutrophil CD44 avidity for hyaluronan was not increased in endotoxemia. Instead, activation of CD44-hyaluronan engagement was the result of qualitative modification of hyaluronan by a dramatic induction of serum-derived hyaluronan-associated protein (SHAP) in sinusoids in response to lipopolysaccharide. Lipopolysaccharide-induced hepatic injury was significantly reduced by inhibiting CD44-hyaluronan interactions. Therapeutic administration of anti-CD44 antibody to endotoxemic mice rapidly detached adherent neutrophils and improved sinusoidal perfusion. Conclusion: These findings reveal CD44 as a potential therapeutic target in systemic inflammatory responses involving liver.

scholarly journals Neutrophil recruitment inhibitory factor: a possible candidate for a novel cytokine

1992 ◽  
Vol 1 (1) ◽  
pp. 49-54 ◽  
Author(s):  
W. M. S. C. Tamashiro ◽  
B. M. Tavares-Murta ◽  
F. Q. Cunha ◽  
M. C. Roque-Barreira ◽  
R. M. D. Nogueira ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
Inflammatory Responses ◽  
Neutrophil Migration ◽  
Gel Filtration ◽  
Inhibitory Effect ◽  
Neutrophil Recruitment ◽  
Tnf Α ◽  
Inflammatory Stimuli

Inhibitory effect upon neutrophil migration to the inflammatory focus was previously detected in the cell-free incubation fluid of lipopolysaccharide (LPS)-stimulated macrophage monolayers. In the present study we showed that the neutrophil recruitment inhibitory activity from this supernatant was mainly detected in a fraction (P2) obtained by gel filtration chromatography on Sephacryl S-300. P2 fraction was able to inhibit ‘in vivo’ neutrophil emigration induced by different inflammatory stimuli, but it did not affect ‘in vitro’ neutrophil chemotaxis induced by FMLP. When injected intravenously, P2 inhibited oedema induced by carrageenin or immunological stimulus but not the oedema induced by dextran, thus affecting cell-dependent inflammatory responses. It was observed that P2 also induced neutrophil migration when injected locally in peritoneal cavities. This activity was significantly reduced by pretreatment of the animals with dexamethasone. Cytokines, such as IL-8 and TNF-α that are known to exhibit inhibitory effect upon neutrophil migration, were not detected in P2 fraction by highly sensitive assays. Overall the results suggest the existence of a novel cytokine exhibiting ‘in vivo’ neutrophil inhibitory activity, referred as NRIF.

ID: 109: PARKIN MEDIATES ENDOTHELIAL PRO-INFLAMMATORY RESPONSES IN ACUTE LUNG INJURY

2016 ◽  
Vol 64 (4) ◽  
pp. 963.1-963
Author(s):  
E Letsiou ◽  
H Wang ◽  
P Belvitch ◽  
S Dudek ◽  
S Sammani
Keyword(s):  
Acute Lung Injury ◽  
Endothelial Dysfunction ◽  
Lung Injury ◽  
Kinase Inhibitor ◽  
Inflammatory Responses ◽  
Neutrophil Adhesion ◽  
Protein Levels ◽  
Cell Counts

IntroductionAcute lung injury (ALI) and its more severe form, the Acute Respiratory Distress Syndrome (ARDS), are serious conditions resulting from direct or indirect lung injury that occur in critically ill patients and are associated with an unacceptable mortality of up to 40%. A key biological event in the pathogenesis of ALI/ARDS is the dysfunction of the lung endothelium (EC), which is triggered by a variety of inflammatory insults leading to damaged EC, vascular leak, and excessive inflammation. Recently, we demonstrated that an Abl family tyrosine kinase inhibitor, imatinib, protects against LPS-induced endothelial dysfunction by inhibiting c-Abl kinase through mechanisms that remain largely unknown. In the present study, we identified parkin, a novel c-Abl substrate, as a critical mediator of endothelial dysfunction in ALI.MethodsIn vitro Human pulmonary artery endothelial cells (EC) were transfected with siRNA for parkin and then challenged with LPS (1 µg/ml, 3 hrs). Inflammatory mediators were determined in cell lysates and supernatants by Western blotting and ELISA respectively. In vivo C57BL/6 (WT) and parkin deficient (PARK2 KO) male mice (8–12 wks, n=5–8) were subjected to LPS (intratracheally, 1 mg/kg) or PBS (controls), and allowed to recover prior to harvest 18 hrs later. Leakage of proteins into the alveolar space was assessed by measuring the protein levels in the bronchoalveolar lavage (BAL). To assess lung inflammation, neutrophil cell counts, myeloperoxidase (MPO) activity, and IL-6 levels were determined in BAL.ResultsIn human lung EC, down-regulation of parkin by siRNA reduces LPS-induced VCAM-1 expression (adhesion molecule involved in neutrophil adhesion to EC) (by 35%, p<0.05), IL-8 (neutrophil chemoattractant) (by 59%, p<0.01), and IL-6 (inflammatory cytokine) release (by 79%, p<0.01). PARK2 KO mice exhibit less ALI after LPS compared to WT. In PARK2 KO, BAL protein levels were reduced by 27% (p=0.0024) compared to WT mice. LPS-induced neutrophil recruitment into the alveoli of PARK2 KO was attenuated by 47% compared to WT (p=0.0019). BAL MPO activity (marker of neutrophil activation) and BAL IL-6 levels were also significantly lower in PARK2 KO by 52% (p=0.03) and 28% (p=0.0061) respectively.ConclusionThese results suggest that endothelial parkin mediates EC activation and neutrophil adhesion/migration after LPS, and therefore it may represent a new potential therapeutic target in ALI/ARDS.

Kupffer cells and activation of endothelial TLR4 coordinate neutrophil adhesion within liver sinusoids during endotoxemia

2013 ◽  
Vol 305 (11) ◽  
pp. G797-G806 ◽  
Author(s):  
Braedon McDonald ◽  
Craig N. Jenne ◽  
Lisheng Zhuo ◽  
Koji Kimata ◽  
Paul Kubes
Keyword(s):  
Bone Marrow ◽  
Kupffer Cells ◽  
Inflammatory Responses ◽  
Vascular Dysfunction ◽  
Neutrophil Recruitment ◽  
Neutrophil Adhesion ◽  
Pathological Feature ◽  
Liver Sinusoids ◽  
Adhesive Interactions ◽  
Tlr4 Activation

A key pathological feature of the systemic inflammatory response of sepsis/endotoxemia is the accumulation of neutrophils within the microvasculature of organs such as the liver, where they cause tissue damage and vascular dysfunction. There is emerging evidence that the vascular endothelium is critical to the orchestration of inflammatory responses to blood-borne microbes and microbial products in sepsis/endotoxemia. In this study, we aimed to understand the role of endothelium, and specifically endothelial TLR4 activation, in the regulation of neutrophil recruitment to the liver during endotoxemia. Intravital microscopy of bone marrow chimeric mice revealed that TLR4 expression by non-bone marrow-derived cells was required for neutrophil recruitment to the liver during endotoxemia. Furthermore, LPS-induced neutrophil adhesion in liver sinusoids was equivalent between wild-type mice and transgenic mice that express TLR4 only on endothelium ( tlr4−/−Tie2 tlr4), revealing that activation of endothelial TLR4 alone was sufficient to initiate neutrophil adhesion. Neutrophil arrest within sinusoids of endotoxemic mice requires adhesive interactions between neutrophil CD44 and endothelial hyaluronan. Intravital immunofluorescence imaging demonstrated that stimulation of endothelial TLR4 alone was sufficient to induce the deposition of serum-derived hyaluronan-associated protein (SHAP) within sinusoids, which was required for CD44/hyaluronan-dependent neutrophil adhesion. In addition to endothelial TLR4 activation, Kupffer cells contribute to neutrophil recruitment via a distinct CD44/HA/SHAP-independent mechanism. This study sheds new light on the control of innate immune activation within the liver vasculature during endotoxemia, revealing a key role for endothelial cells as sentinels in the detection of intravascular infections and coordination of neutrophil recruitment to the liver.

scholarly journals Lipoproteins Are Responsible for the Pro-Inflammatory Property of Staphylococcus aureus Extracellular Vesicles

2021 ◽  
Vol 22 (13) ◽  
pp. 7099
Author(s):  
Pradeep Kumar Kopparapu ◽  
Meghshree Deshmukh ◽  
Zhicheng Hu ◽  
Majd Mohammad ◽  
Marco Maugeri ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Inflammatory Responses ◽  
Surface Proteins ◽  
Host Cells ◽  
Immune Stimulation ◽  
Domains Of Life ◽  
Major Surface ◽  
Staphylococcal Aureus

Staphylococcal aureus (S. aureus), a Gram-positive bacteria, is known to cause various infections. Extracellular vesicles (EVs) are a heterogeneous array of membranous structures secreted by cells from all three domains of life, i.e., eukaryotes, bacteria, and archaea. Bacterial EVs are implied to be involved in both bacteria–bacteria and bacteria–host interactions during infections. It is still unclear how S. aureus EVs interact with host cells and induce inflammatory responses. In this study, EVs were isolated from S. aureus and mutant strains deficient in either prelipoprotein lipidation (Δlgt) or major surface proteins (ΔsrtAB). Their immunostimulatory capacities were assessed both in vitro and in vivo. We found that S. aureus EVs induced pro-inflammatory responses both in vitro and in vivo. However, this activity was dependent on lipidated lipoproteins (Lpp), since EVs isolated from the Δlgt showed no stimulation. On the other hand, EVs isolated from the ΔsrtAB mutant showed full immune stimulation, indicating the cell wall anchoring of surface proteins did not play a role in immune stimulation. The immune stimulation of S. aureus EVs was mediated mainly by monocytes/macrophages and was TLR2 dependent. In this study, we demonstrated that not only free Lpp but also EV-imbedded Lpp had high pro-inflammatory activity.

scholarly journals Involvement of HECTD1 in LPS-induced astrocyte activation via σ-1R-JNK/p38-FOXJ2 axis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ying Tang ◽  
Mengchun Zhou ◽  
Rongrong Huang ◽  
Ling Shen ◽  
Li Yang ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Astrocyte Activation ◽  
Hect Domain ◽  
P38 Inhibitor ◽  
Ubiquitin Protein Ligase ◽  
Primary Mouse ◽  
Lps Treatment

Abstract Background Astrocytes participate in innate inflammatory responses within the mammalian central nervous system (CNS). HECT domain E3 ubiquitin protein ligase 1 (HECTD1) functions during microglial activation, suggesting a connection with neuroinflammation. However, the potential role of HECTD1 in astrocytes remains largely unknown. Results Here, we demonstrated that HECTD1 was upregulated in primary mouse astrocytes after 100 ng/ml lipopolysaccharide (LPS) treatment. Genetic knockdown of HECTD1 in vitro or astrocyte-specific knockdown of HECTD1 in vivo suppressed LPS-induced astrocyte activation, whereas overexpression of HECTD1 in vitro facilitated LPS-induced astrocyte activation. Mechanistically, we established that LPS activated σ-1R-JNK/p38 pathway, and σ-1R antagonist BD1047, JNK inhibitor SP600125, or p38 inhibitor SB203580 reversed LPS-induced expression of HECTD1, thus restored LPS-induced astrocyte activation. In addition, FOXJ2 functioned as a transcription factor of HECTD1, and pretreatment of primary mouse astrocytes with BD1047, SB203580, and SP600125 significantly inhibited LPS-mediated translocation of FOXJ2 into the nucleus. Conclusions Overall, our present findings suggest that HECTD1 participates in LPS-induced astrocyte activation by activation of σ-1R-JNK/p38-FOXJ2 pathway and provide a potential therapeutic strategy for neuroinflammation induced by LPS or any other neuroinflammatory disorders.

scholarly journals Eap1p, an Adhesin That Mediates Candida albicans Biofilm Formation In Vitro and In Vivo

2007 ◽  
Vol 6 (6) ◽  
pp. 931-939 ◽  
Author(s):  
Fang Li ◽  
Michael J. Svarovsky ◽  
Amy J. Karlsson ◽  
Joel P. Wagner ◽  
Karen Marchillo ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Cell Adhesion ◽  
Biofilm Formation ◽  
Fungal Infections ◽  
Gene Dosage ◽  
Venous Catheter ◽  
Flow Chamber ◽  
Dependent Manner

ABSTRACT Candida albicans is the leading cause of systemic fungal infections in immunocompromised humans. The ability to form biofilms on surfaces in the host or on implanted medical devices enhances C. albicans virulence, leading to antimicrobial resistance and providing a reservoir for infection. Biofilm formation is a complex multicellular process consisting of cell adhesion, cell growth, morphogenic switching between yeast form and filamentous states, and quorum sensing. Here we describe the role of the C. albicans EAP1 gene, which encodes a glycosylphosphatidylinositol-anchored, glucan-cross-linked cell wall protein, in adhesion and biofilm formation in vitro and in vivo. Deleting EAP1 reduced cell adhesion to polystyrene and epithelial cells in a gene dosage-dependent manner. Furthermore, EAP1 expression was required for C. albicans biofilm formation in an in vitro parallel plate flow chamber model and in an in vivo rat central venous catheter model. EAP1 expression was upregulated in biofilm-associated cells in vitro and in vivo. Our results illustrate an association between Eap1p-mediated adhesion and biofilm formation in vitro and in vivo.

scholarly journals Nociceptive Sensitization by Activation of Protease-Activated Receptor 2 in a Rat Model of Incisional Pain

2021 ◽  
Vol 11 (2) ◽  
pp. 144
Author(s):  
Kanta Kido ◽  
Norika Katagiri ◽  
Hiromasa Kawana ◽  
Shigekazu Sugino ◽  
Masanori Yamauchi ◽  
...  
Keyword(s):  
Postoperative Pain ◽  
Inflammatory Responses ◽  
Early Period ◽  
Intraplantar Injection ◽  
C Fibers ◽  
Nociceptive Responses ◽  
Incisional Pain ◽  
Protease Activated Receptor 2

Postoperative pain and consequent inflammatory responses after tissue incision adversely affects many surgical patients due to complicated mechanisms. In this study, we examined whether activation of protease-activated receptor 2 (PAR-2), which is stimulated by tryptase from mast cells, elicits nociception and whether the PAR-2 antagonist could reduce incisional nociceptive responses in vivo and in vitro. The effects of a selective PAR-2 antagonist, N3-methylbutyryl-N-6-aminohexanoyl-piperazine (ENMD-1068), pretreatment on pain behaviors were assessed after plantar incision in rats. The effects of a PAR-2 agonist, SLIGRL-NH2, on nociception was assessed after the injection into the hind paw. Furthermore, the responses of C-mechanosensitive nociceptors to the PAR-2 agonist were observed using an in vitro skin–nerve preparation as well. Intraplantar injection of SLIGRL-NH2 elicited spontaneous nociceptive behavior and hyperalgesia. Local administration of ENMD-1068 suppressed guarding behaviors, mechanical and heat hyperalgesia only within the first few hours after incision. SLIGRL-NH2 caused ongoing activity in 47% of C-mechanonociceptors in vitro. This study suggests that PAR-2 may support early nociception after incision by direct or indirect sensitization of C-fibers in rats. Moreover, PAR-2 may play a regulatory role in the early period of postoperative pain together with other co-factors to that contribute to postoperative pain.

scholarly journals In Vitro Evaluation of the Anti-Inflammatory Effect of KMUP-1 and in Vivo Analysis of Its Therapeutic Potential in Osteoarthritis

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 615
Author(s):  
Shang-En Huang ◽  
Erna Sulistyowati ◽  
Yu-Ying Chao ◽  
Bin-Nan Wu ◽  
Zen-Kong Dai ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Inflammatory Responses ◽  
Therapeutic Potential ◽  
Antioxidant Properties ◽  
Serum Levels ◽  
Gene Expressions ◽  
Tnf Α ◽  
Anti Inflammatory

Osteoarthritis is a degenerative arthropathy that is mainly characterized by dysregulation of inflammatory responses. KMUP-1, a derived chemical synthetic of xanthine, has been shown to have anti-inflammatory and antioxidant properties. Here, we aimed to investigate the in vitro anti-inflammatory and in vivo anti-osteoarthritis effects of KMUP-1. Protein and gene expressions of inflammation markers were determined by ELISA, Western blotting and microarray, respectively. RAW264.7 mouse macrophages were cultured and pretreated with KMUP-1 (1, 5, 10 μM). The productions of TNF-α, IL-6, MMP-2 and MMP- 9 were reduced by KMUP-1 pretreatment in LPS-induced inflammation of RAW264.7 cells. The expressions of iNOS, TNF-α, COX-2, MMP-2 and MMP-9 were also inhibited by KMUP-1 pretreatment. The gene expression levels of TNF and COX families were also downregulated. In addition, KMUP-1 suppressed the activations of ERK, JNK and p38 as well as phosphorylation of IκBα/NF-κB signaling pathways. Furthermore, SIRT1 inhibitor attenuated the inhibitory effect of KMUP-1 in LPS-induced NF-κB activation. In vivo study showed that KMUP-1 reduced mechanical hyperalgesia in monoiodoacetic acid (MIA)-induced rats OA. Additionally, KMUP-1 pretreatment reduced the serum levels of TNF-α and IL-6 in MIA-injected rats. Moreover, macroscopic and histological observation showed that KMUP-1 reduced articular cartilage erosion in rats. Our results demonstrated that KMUP-1 inhibited the inflammatory responses and restored SIRT1 in vitro, alleviated joint-related pain and cartilage destruction in vivo. Taken together, KMUP-1 has the potential to improve MIA-induced articular cartilage degradation by inhibiting the levels and expression of inflammatory mediators suggesting that KMUP-1 might be a potential therapeutic agent for OA.

scholarly journals Role of the C5a-C5a receptor axis in the inflammatory responses of the lungs after experimental polytrauma and hemorrhagic shock

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shinjini Chakraborty ◽  
Veronika Eva Winkelmann ◽  
Sonja Braumüller ◽  
Annette Palmer ◽  
Anke Schultze ◽  
...  
Keyword(s):  
Hemorrhagic Shock ◽  
Inflammatory Responses ◽  
Experimental Models ◽  
Lung Damage ◽  
C5a Receptor ◽  
Cytokine Levels ◽  
Vitro Model

AbstractSingular blockade of C5a in experimental models of sepsis is known to confer protection by rescuing lethality and decreasing pro-inflammatory responses. However, the role of inhibiting C5a has not been evaluated in the context of sterile systemic inflammatory responses, like polytrauma and hemorrhagic shock (PT + HS). In our presented study, a novel and highly specific C5a L-aptamer, NoxD21, was used to block C5a activity in an experimental murine model of PT + HS. The aim of the study was to assess early modulation of inflammatory responses and lung damage 4 h after PT + HS induction. NoxD21-treated PT + HS mice displayed greater polymorphonuclear cell recruitment in the lung, increased pro-inflammatory cytokine levels in the bronchoalveolar lavage fluids (BALF) and reduced myeloperoxidase levels within the lung tissue. An in vitro model of the alveolar-capillary barrier was established to confirm these in vivo observations. Treatment with a polytrauma cocktail induced barrier damage only after 16 h, and NoxD21 treatment in vitro did not rescue this effect. Furthermore, to test the exact role of both the cognate receptors of C5a (C5aR1 and C5aR2), experimental PT + HS was induced in C5aR1 knockout (C5aR1 KO) and C5aR2 KO mice. Following 4 h of PT + HS, C5aR2 KO mice had significantly reduced IL-6 and IL-17 levels in the BALF without significant lung damage, and both, C5aR1 KO and C5aR2 KO PT + HS animals displayed reduced MPO levels within the lungs. In conclusion, the C5aR2 could be a putative driver of early local inflammatory responses in the lung after PT + HS.

scholarly journals A sand fly salivary protein acts as a neutrophil chemoattractant

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Anderson B. Guimaraes-Costa ◽  
John P. Shannon ◽  
Ingrid Waclawiak ◽  
Jullyanna Oliveira ◽  
Claudio Meneses ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Calcium Influx ◽  
Parasite Burden ◽  
Salivary Protein ◽  
Sand Fly ◽  
Human Neutrophils ◽  
Chemotactic Protein ◽  
The Impact

AbstractApart from bacterial formyl peptides or viral chemokine mimicry, a non-vertebrate or insect protein that directly attracts mammalian innate cells such as neutrophils has not been molecularly characterized. Here, we show that members of sand fly yellow salivary proteins induce in vitro chemotaxis of mouse, canine and human neutrophils in transwell migration or EZ-TAXIScan assays. We demonstrate murine neutrophil recruitment in vivo using flow cytometry and two-photon intravital microscopy in Lysozyme-M-eGFP transgenic mice. We establish that the structure of this ~ 45 kDa neutrophil chemotactic protein does not resemble that of known chemokines. This chemoattractant acts through a G-protein-coupled receptor and is dependent on calcium influx. Of significance, this chemoattractant protein enhances lesion pathology (P < 0.0001) and increases parasite burden (P < 0.001) in mice upon co-injection with Leishmania parasites, underlining the impact of the sand fly salivary yellow proteins on disease outcome. These findings show that some arthropod vector-derived factors, such as this chemotactic salivary protein, activate rather than inhibit the host innate immune response, and that pathogens take advantage of these inflammatory responses to establish in the host.

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