scholarly journals The LTB4-BLT1 axis regulates actomyosin and β2 integrin dynamics during neutrophil extravasation

2019 ◽  
Author(s):  
Bhagawat C. Subramanian ◽  
Nicolas Melis ◽  
Desu Chen ◽  
Weiye Wang ◽  
Devorah Gallardo ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Neutrophil Migration ◽  
Cell Polarization ◽  
Sterile Inflammation ◽  
Paracrine Signaling ◽  
Neutrophil Extravasation ◽  
Actomyosin Cytoskeleton ◽  
Neutrophil Response ◽  
Muscle Myosin

ABSTRACTThe eicosanoid Leukotriene B4 (LTB4) relays chemotactic signals to direct neutrophil migration to inflamed sites through its receptor BLT1. However, the mechanisms by which the LTB4-BLT1 axis relays chemotactic signals during intravascular neutrophil response to inflammation remain unclear. Here, we report that LTB4 produced by neutrophils acts as an autocrine/paracrine signal to direct the vascular recruitment, arrest and extravasation of neutrophils in a sterile inflammation model in the mouse footpad. Using Intravital Subcellular Microscopy (ISMic), we reveal that LTB4 elicits sustained cell polarization and adhesion responses during neutrophil arrest in vivo. Specifically, LTB4 signaling coordinates the dynamic redistribution of non-muscle Myosin IIA (NMIIA) and β2-integrin (Itgb2), which facilitate neutrophil arrest and extravasation. Notably, we also found that neutrophils shed extracellular vesicles (EVs) in the vascular lumen, and that inhibition of EV release blocks LTB4-mediated autocrine/paracrine signaling required for neutrophil arrest and extravasation. Overall, we uncover a novel complementary mechanism by which LTB4 relays extravasation signals in neutrophils during early inflammation response.SUMMARYNeutrophils arrest and extravasate from the blood vessels in response to infection and injury. Using intravital subcellular microscopy, Subramanian et al. identify a role for extracellular vesicles-based autocrine/paracrine LTB4-BLT1 signaling in promoting the re-arrangement of actomyosin cytoskeleton and β2-integrin during neutrophil extravasation in live animals.

scholarly journals The LTB4–BLT1 axis regulates actomyosin and β2-integrin dynamics during neutrophil extravasation

2020 ◽  
Vol 219 (10) ◽  
Author(s):  
Bhagawat C. Subramanian ◽  
Nicolas Melis ◽  
Desu Chen ◽  
Weiye Wang ◽  
Devorah Gallardo ◽  
...  
Keyword(s):  
Neutrophil Migration ◽  
Extracellular Vesicle ◽  
Leukotriene B4 ◽  
Cell Polarization ◽  
Sterile Inflammation ◽  
Β2 Integrin ◽  
Neutrophil Extravasation ◽  
Neutrophil Response ◽  
Muscle Myosin

The eicosanoid leukotriene B4 (LTB4) relays chemotactic signals to direct neutrophil migration to inflamed sites through its receptor BLT1. However, the mechanisms by which the LTB4–BLT1 axis relays chemotactic signals during intravascular neutrophil response to inflammation remain unclear. Here, we report that LTB4 produced by neutrophils acts as an autocrine/paracrine signal to direct the vascular recruitment, arrest, and extravasation of neutrophils in a sterile inflammation model in the mouse footpad. Using intravital subcellular microscopy, we reveal that LTB4 elicits sustained cell polarization and adhesion responses during neutrophil arrest in vivo. Specifically, LTB4 signaling coordinates the dynamic redistribution of non-muscle myosin IIA and β2-integrin, which facilitate neutrophil arrest and extravasation. Notably, we also found that neutrophils shed extracellular vesicles in the vascular lumen and that inhibition of extracellular vesicle release blocks LTB4-mediated autocrine/paracrine signaling required for neutrophil arrest and extravasation. Overall, we uncover a novel complementary mechanism by which LTB4 relays extravasation signals in neutrophils during early inflammation response.

scholarly journals The Macrophage-derived Lectin, MNCF, Activates Neutrophil Migration through a Pertussis Toxin-sensitive Pathway

2005 ◽  
Vol 53 (6) ◽  
pp. 715-723 ◽  
Author(s):  
Andréa N. Moreno ◽  
Gabriela Pereira-da-Silva ◽  
Constance Oliver ◽  
Maria Célia Jamur ◽  
Ademilson Panunto-Castelo ◽  
...  
Keyword(s):  
Cell Surface ◽  
Pertussis Toxin ◽  
Neutrophil Migration ◽  
Cell Polarization ◽  
Glucocorticoid Treatment ◽  
Neutrophil Chemotactic Factor ◽  
G Protein Coupled ◽  
Neutrophil Surface

The macrophage-derived neutrophil chemotactic factor (MNCF) is a d-galactose-binding lectin that induces neutrophil migration in vitro and in vivo. Neutrophil recruitment induced by MNCF is resistant to glucocorticoid treatment and is inhibited by the lectin-specific sugar, d-galactose. In the present study, we characterized the binding of MNCF to neutrophils and the responses triggered by this binding. Exposure to MNCF resulted in cell polarization, formation of a lamellipodium, and deep ruffles on the cell surface. By confocal microscopy, we observed that MNCF was evenly distributed on the cell surface after 30 min of incubation. The labeling intensity progressively diminished with longer incubations. Internalization kinetics showed that MNCF/ligand complexes were rapidly internalized, reaching maximum intracellular concentrations at 120 min and then decreased thereafter. The binding and internalization of MNCF were selectively inhibited by d-galactose. MNCF-induced neutrophil chemotaxis was inhibited by pertussis toxin. This fact strongly suggests that the MNCF-ligand on the neutrophil surface is a G-protein-coupled receptor (GPCR), similar to receptors for well-established neutrophil attractants. Our observations on the ability of MNCF to activate neutrophils are consistent with the increasing evidence for the participation of animal lectins in the innate immune response.

scholarly journals Molecular Insights Into Neutrophil Biology From the Zebrafish Perspective: Lessons From CD18 Deficiency

2021 ◽  
Vol 12 ◽  
Author(s):  
Almke Bader ◽  
Jincheng Gao ◽  
Thibaud Rivière ◽  
Bettina Schmid ◽  
Barbara Walzog ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Neutrophil Migration ◽  
Amino Acid Sequences ◽  
Sterile Inflammation ◽  
Type I ◽  
Hematopoietic Tissue ◽  
Sequence Alignments ◽  
Zebrafish Larvae ◽  
Inflamed Tissue

Neutrophils are key players in innate immunity and originate from the bone marrow of the adult mammalian organism. In mammals, mature neutrophils are released from the bone marrow into the peripheral blood where they circulate until their recruitment to sites of inflammation in a multistep adhesion cascade. Here, adhesion molecules of the β2 integrin family (CD11/CD18) are critically required for the initial neutrophil adhesion to the inflamed endothelium and several post-adhesion steps allowing their extravasation into the inflamed tissue. Within the mammalian tissue, interstitial neutrophil migration can occur widely independent of β2 integrins. This is in sharp contrast to neutrophil recruitment in zebrafish larvae (Danio rerio) where neutrophils originate from the caudal hematopoietic tissue and mainly migrate interstitially to sites of lesion upon the early onset of inflammation. However, neutrophils extravasate from the circulation to the inflamed tissue in zebrafish larvae at later-time points. Although zebrafish larvae are a widely accepted model system to analyze neutrophil trafficking in vivo, the functional impact of β2 integrins for neutrophil trafficking during acute inflammation is completely unknown in this model. In this study, we generated zebrafish with a genetic deletion of CD18, the β subunit of β2 integrins, using CRISPR/Cas9 technology. Sequence alignments demonstrated a high similarity of the amino acid sequences between zebrafish and human CD18 especially in the functionally relevant I-like domain. In addition, the cytoplasmic domain of CD18 harbors two highly conserved NXXF motifs suggesting that zebrafish CD18 may share functional properties of human CD18. Accordingly, CD18 knock-out (KO) zebrafish larvae displayed the key symptoms of patients suffering from leukocyte adhesion deficiency (LAD) type I due to defects in ITGB2, the gene for CD18. Importantly, CD18 KO zebrafish larvae showed reduced neutrophil trafficking to sites of sterile inflammation despite the fact that an increased number of neutrophils was detectable in the circulation. By demonstrating the functional importance of CD18 for neutrophil trafficking in zebrafish larvae, our findings shed new light on neutrophil biology in vertebrates and introduce a new model organism for studying LAD type I.

scholarly journals A neutrophil-centric view of chemotaxis

2019 ◽  
Vol 63 (5) ◽  
pp. 607-618 ◽  
Author(s):  
Melina Michael ◽  
Sonja Vermeren
Keyword(s):  
Chemokine Receptors ◽  
Neutrophil Migration ◽  
G Protein Coupled Receptors ◽  
Innate Immune ◽  
Resolution Of Inflammation ◽  
Neutrophil Extravasation ◽  
Recent Developments ◽  
G Protein Coupled

Abstract Neutrophils are key players of the innate immune system, that are involved in coordinating the initiation, propagation and resolution of inflammation. Accurate neutrophil migration (chemotaxis) to sites of inflammation in response to gradients of chemoattractants is pivotal to these roles. Binding of chemoattractants to dedicated G-protein-coupled receptors (GPCRs) initiates downstream signalling events that promote neutrophil polarisation, a prerequisite for directional migration. We provide a brief summary of some of the recent insights into signalling events and feedback loops that serve to initiate and maintain neutrophil polarisation. This is followed by a discussion of recent developments in the understanding of in vivo neutrophil chemotaxis, a process that is frequently referred to as ‘recruitment’ or ‘trafficking’. Here, we summarise neutrophil mobilisation from and homing to the bone marrow, and briefly discuss the role of glucosaminoglycan-immobilised chemoattractants and their corresponding receptors in the regulation of neutrophil extravasation and neutrophil swarming. We furthermore touch on some of the most recent insights into the roles of atypical chemokine receptors (ACKRs) in neutrophil recruitment, and discuss neutrophil reverse (transendothelial) migration together with potential function(s) in the dissemination and/or resolution of inflammation.

A Systematic Review on Extracellular Vesicles-Enriched Fat Grafting: A Shifting Paradigm

2020 ◽  
Author(s):  
Mohammad Ghiasloo ◽  
Laura De Wilde ◽  
Kashika Singh ◽  
Patrick Tonnard ◽  
Alexis Verpaele ◽  
...  
Keyword(s):  
Systematic Review ◽  
Graft Survival ◽  
Extracellular Vesicles ◽  
Retention Rate ◽  
Fat Grafting ◽  
Retention Rates ◽  
Fat Graft ◽  
Cochrane Central Register

Abstract Background Recent evidence confirms that mesenchymal stem cells (MSCs) facilitate angiogenesis mainly through paracrine function. Extracellular vesicles (EVs) are regarded as key components of the cell secretome, possessing functional properties of their source cells. Subsequently, MSC-EVs have emerged as a novel cell-free approach to improve fat graft retention rate. Objectives To provide a systematic review of all studies reporting the use of MSC-EVs to improve graft retention rate. Methods A systematic search was undertaken using the Embase, PubMed and the Cochrane Central Register of Controlled Trials databases. Outcome measures included donor/receptor organism of the fat graft, study model, intervention groups, evaluation intervals, EV research data, in vitro and in vivo results. Results Of the total 1717 articles, 62 full-texts were screened. Seven studies reporting on 294mice were included. Overall, EV treated groups showed higher graft retention rates compared to untreated groups. Notably, retention rate was similar following EV- and MSC-treatment. In addition to reduced inflammation, graft enrichment with EVs resulted in early revascularization and better graft integrity. Interestingly, hypoxic preconditioning of MSCs improved their beneficial paracrine effects and led to a more proangiogenic EV population, as observed by both in vitro and in vivo results. Conclusions MSC-EVs appear to offer an interesting cell-free alternative to improve fat graft survival. While their clinical relevance remains to be determined, it is clear that not the cells, but their secretome is essential for graft survival. Thus, a paradigm shift from cell-assisted lipotransfer towards ‘secretome-assisted lipotransfer’ is well on its way.

scholarly journals Cancer-associated fibroblast secretion of PDGFC promotes gastrointestinal stromal tumor growth and metastasis

Oncogene ◽  
2021 ◽  
Vol 40 (11) ◽  
pp. 1957-1973
Author(s):  
Hyunho Yoon ◽  
Chih-Min Tang ◽  
Sudeep Banerjee ◽  
Mayra Yebra ◽  
Sangkyu Noh ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Tumor Growth ◽  
Gastrointestinal Stromal Tumor ◽  
Single Agent ◽  
Stromal Tumor ◽  
Paracrine Signaling ◽  
Mesenchymal Transition ◽  
Tumor Growth And Metastasis ◽  
Factor C

AbstractTargeted therapies for gastrointestinal stromal tumor (GIST) are modestly effective, but GIST cannot be cured with single agent tyrosine kinase inhibitors. In this study, we sought to identify new therapeutic targets in GIST by investigating the tumor microenvironment. Here, we identified a paracrine signaling network by which cancer-associated fibroblasts (CAFs) drive GIST growth and metastasis. Specifically, CAFs isolated from human tumors were found to produce high levels of platelet-derived growth factor C (PDGFC), which activated PDGFC-PDGFRA signal transduction in GIST cells that regulated the expression of SLUG, an epithelial-mesenchymal transition (EMT) transcription factor and downstream target of PDGFRA signaling. Together, this paracrine induce signal transduction cascade promoted tumor growth and metastasis in vivo. Moreover, in metastatic GIST patients, SLUG expression positively correlated with tumor size and mitotic index. Given that CAF paracrine signaling modulated GIST biology, we directly targeted CAFs with a dual PI3K/mTOR inhibitor, which synergized with imatinib to increase tumor cell killing and in vivo disease response. Taken together, we identified a previously unappreciated cellular target for GIST therapy in order to improve disease control and cure rates.

scholarly journals microRNA-186 in extracellular vesicles from bone marrow mesenchymal stem cells alleviates idiopathic pulmonary fibrosis via interaction with SOX4 and DKK1

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Zhou ◽  
Yang Lin ◽  
Xiuhua Kang ◽  
Zhicheng Liu ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Extracellular Vesicles ◽  
Luciferase Assay ◽  
Therapeutic Effects ◽  
Loss Of Function ◽  
Fibroblast Activation ◽  
Promising Therapeutic Approach

Abstract Background Previous reports have identified that human bone marrow mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) with their cargo microRNAs (miRNAs) are a promising therapeutic approach for the treatment of idiopathic pulmonary fibrosis (IPF). Therefore, we explored whether delivery of microRNA-186 (miR-186), a downregulated miRNA in IPF, by BMSC EVs could interfere with the progression of IPF in a murine model. Methods In a co-culture system, we assessed whether BMSC-EVs modulated the activation of fibroblasts. We established a mouse model of PF to evaluate the in vivo therapeutic effects of BMSC-EVs and determined miR-186 expression in BMSC-EVs by polymerase chain reaction. Using a loss-of-function approach, we examined how miR-186 delivered by BMSC-EVs affected fibroblasts. The putative relationship between miR-186 and SRY-related HMG box transcription factor 4 (SOX4) was tested using luciferase assay. Next, we investigated whether EV-miR-186 affected fibroblast activation and PF by targeting SOX4 and its downstream gene, Dickkopf-1 (DKK1). Results BMSC-EVs suppressed lung fibroblast activation and delayed IPF progression in mice. miR-186 was downregulated in IPF but enriched in the BMSC-EVs. miR-186 delivered by BMSC-EVs could suppress fibroblast activation. Furthermore, miR-186 reduced the expression of SOX4, a target gene of miR-186, and hence suppressed the expression of DKK1. Finally, EV-delivered miR-186 impaired fibroblast activation and alleviated PF via downregulation of SOX4 and DKK1. Conclusion In conclusion, miR-186 delivered by BMSC-EVs suppressed SOX4 and DKK1 expression, thereby blocking fibroblast activation and ameliorating IPF, thus presenting a novel therapeutic target for IPF.

scholarly journals Plant-Derived Extracellular Vesicles: Current Findings,Challenges, and Future Applications

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 411
Author(s):  
Nader Kameli ◽  
Anya Dragojlovic-Kerkache ◽  
Paul Savelkoul ◽  
Frank R. Stassen
Keyword(s):  
Human Health ◽  
Extracellular Vesicles ◽  
Preliminary Results ◽  
In Vivo Experiments ◽  
Health And Disease ◽  
Conducting Research ◽  
Protocol Standardization ◽  
Insight Into

In recent years, plant-derived extracellular vesicles (PDEVs) have gained the interest of many experts in fields such as microbiology and immunology, and research in this field has exponentially increased. These nano-sized particles have provided researchers with a number of interesting findings, making their application in human health and disease very promising. Both in vitro and in vivo experiments have shown that PDEVs can exhibit a multitude of effects, suggesting that these vesicles may have many potential future applications, including therapeutics and nano-delivery of compounds. While the preliminary results are promising, there are still some challenges to face, such as a lack of protocol standardization, as well as knowledge gaps that need to be filled. This review aims to discuss various aspects of PDEV knowledge, including their preliminary findings, challenges, and future uses, giving insight into the complexity of conducting research in this field.

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 The Therapeutic Effect of Extracellular Vesicles on Asthma in Pre-Clinical Models: A Systematic Review Protocol

2021 ◽  
Vol 1 (1) ◽  
pp. 84-95
Author(s):  
Patience O. Obi ◽  
Jennifer E. Kent ◽  
Maya M. Jeyaraman ◽  
Nicole Askin ◽  
Taiana M. Pierdoná ◽  
...  
Keyword(s):  
Systematic Review ◽  
Extracellular Vesicles ◽  
Current Knowledge ◽  
Grey Literature ◽  
Specific Treatment ◽  
Therapeutic Effects ◽  
Management Options ◽  
Paracrine Signalling

Asthma is the most common pediatric disease, characterized by chronic airway inflammation and airway hyperresponsiveness. There are several management options for asthma, but no specific treatment. Extracellular vesicles (EVs) are powerful cellular mediators of endocrine, autocrine and paracrine signalling, and can modulate biophysiological function in vitro and in vivo. A thorough investigation of therapeutic effects of EVs in asthma has not been conducted. Therefore, this systematic review is designed to synthesize recent literature on the therapeutic effects of EVs on physiological and biological outcomes of asthma in pre-clinical studies. An electronic search of Web of Science, EMBASE, MEDLINE, and Scopus will be conducted on manuscripts published in the last five years that adhere to standardized guidelines for EV research. Grey literature will also be included. Two reviewers will independently screen the selected studies for title and abstract, and full text based on the eligibility criteria. Data will be extracted, narratively synthesized and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. This systematic review will summarize the current knowledge from preclinical studies investigating the therapeutic effects of EVs on asthma. The results will delineate whether EVs can mitigate biological hallmarks of asthma, and if so, describe the underlying mechanisms involved in the process. This insight is crucial for identifying key pathways that can be targeted to alleviate the burden of asthma. The data will also reveal the origin, dosage and biophysical characteristics of beneficial EVs. Overall, our results will provide a scaffold for future intervention and translational studies on asthma treatment.

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