scholarly journals The Release Kinetics of Eosinophil Peroxidase and Mitochondrial DNA Is Different in Association with Eosinophil Extracellular Trap Formation

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 306
Author(s):  
Nina Germic ◽  
Timothée Fettrelet ◽  
Darko Stojkov ◽  
Aref Hosseini ◽  
Michael P. Horn ◽  
...  

Eosinophils are a subset of granulocytes characterized by a high abundance of specific granules in their cytoplasm. To act as effector cells, eosinophils degranulate and form eosinophil extracellular traps (EETs), which contain double-stranded DNA (dsDNA) co-localized with granule proteins. The exact molecular mechanism of EET formation remains unknown. Although the term “EET release” has been used in scientific reports, it is unclear whether EETs are pre-formed in eosinophils and subsequently released. Moreover, although eosinophil degranulation has been extensively studied, a precise time-course of granule protein release has not been reported until now. In this study, we investigated the time-dependent release of eosinophil peroxidase (EPX) and mitochondrial DNA (mtDNA) following activation of both human and mouse eosinophils. Unexpectedly, maximal degranulation was already observed within 1 min with no further change upon complement factor 5 (C5a) stimulation of interleukin-5 (IL-5) or granulocyte/macrophage colony-stimulating factor (GM-CSF)-primed eosinophils. In contrast, bulk mtDNA release in the same eosinophil populations occurred much slower and reached maximal levels between 30 and 60 min. Although no single-cell analyses have been performed, these data suggest that the molecular pathways leading to degranulation and mtDNA release are at least partially different. Moreover, based on these data, it is likely that the association between the mtDNA scaffold and granule proteins in the process of EET formation occurs in the extracellular space.

Blood ◽  
1995 ◽  
Vol 86 (9) ◽  
pp. 3507-3516 ◽  
Author(s):  
KA Scoggan ◽  
AW Ford-Hutchinson ◽  
DW Nicholson

Cytokines can stimulate eosinophils to produce cysteinyl leukotrienes (LTs) in the lung that provoke tissue destruction associated with asthma. Priming of an eosinophilic substrain of HL-60 cells (HL-60#7) with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) before ionophore challenge was found to produce an apparent 45% increase in total LT production in a dose-dependent manner (ED50 = 150 pmol/L) that could be accounted for by a decrease in the time required for maximal formation of LTs. GM-CSF had no effect on the kinetic parameters of LTC4 synthase and therefore probably acts upstream of this catalytic event. Incubation with interleukin-5 (IL-5), however, had no effect on LT biosynthesis. This differential priming ability was not a consequence of different receptor populations or differences in the affinity or stability of the ligand-receptor complexes of GM-CSF and IL-5. GM-CSF and IL-5 each displayed similar populations of high-affinity binding sites and neither GM-CSF nor IL-5 were able to cross-compete for the other's receptor binding sites. Analysis of phosphotyrosine patterns suggest that IL-5 is incapable of transducing a signal in eosinophilic HL-60#7 cells even though IL-5 and GM-CSF receptors mediate signal transduction via a common beta-chain component that is also necessary for high-affinity binding. Overall, this unique system may permit the dissection of distinct events responsible for specific intracellular signals transduced separately by GM-CSF or IL-5.


Blood ◽  
1999 ◽  
Vol 94 (6) ◽  
pp. 1943-1951 ◽  
Author(s):  
Q. Sun ◽  
K. Jones ◽  
B. McClure ◽  
B. Cambareri ◽  
B. Zacharakis ◽  
...  

Abstract Human interleukin-5 (IL-5), granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-3 are eosinophilopoietic cytokines implicated in allergy in general and in the inflammation of the airways specifically as seen in asthma. All 3 cytokines function through cell surface receptors that comprise a ligand-specific  chain and a shared subunit (βc). Although binding of IL-5, GM-CSF, and IL-3 to their respective receptor  chains is the first step in receptor activation, it is the recruitment of βc that allows high-affinity binding and signal transduction to proceed. Thus, βc is a valid yet untested target for antiasthma drugs with the added advantage of potentially allowing antagonism of all 3 eosinophil-acting cytokines with a single compound. We show here the first development of such an agent in the form of a monoclonal antibody (MoAb), BION-1, raised against the isolated membrane proximal domain of βc. BION-1 blocked eosinophil production, survival, and activation stimulated by IL-5 as well as by GM-CSF and IL-3. Studies of the mechanism of this antagonism showed that BION-1 prevented the high-affinity binding of125I–IL-5, 125I–GM-CSF, and125I–IL-3 to purified human eosinophils and that it bound to the major cytokine binding site of βc. Interestingly, epitope analysis using several βc mutants showed that BION-1 interacted with residues different from those used by IL-5, GM-CSF, and IL-3. Furthermore, coimmunoprecipitation experiments showed that BION-1 prevented ligand-induced receptor dimerization and phosphorylation of βc, suggesting that ligand contact with βc is a prerequisite for recruitment of βc, receptor dimerization, and consequent activation. These results demonstrate the feasibility of simultaneously inhibiting IL-5, GM-CSF, and IL-3 function with a single agent and that BION-1 represents a new tool and lead compound with which to identify and generate further agents for the treatment of eosinophil-dependent diseases such as asthma.


Blood ◽  
1999 ◽  
Vol 93 (10) ◽  
pp. 3391-3400 ◽  
Author(s):  
John F. Fuller ◽  
Jeanne McAdara ◽  
Yifah Yaron ◽  
Mark Sakaguchi ◽  
John K. Fraser ◽  
...  

During the process of normal hematopoiesis, proliferation is tightly linked to maturation. The molecular mechanisms that lead to production of mature effector cells with a variety of phenotypes and functions from a single multipotent progenitor are only beginning to be elucidated. It is important to determine how these maturation events are regulated at the molecular level, because this will provide significant insights into the process of normal hematopoiesis as well as leukemogenesis. Transcription factors containing the highly conserved homeobox motif show considerable promise as potential regulators of hematopoietic maturation events. In this study, we focused on identification and characterization of homeobox genes of the HOX family that are important in regulating normal human myeloid differentiation induced by the hematopoietic growth factor, granulocyte-macrophage colony-stimulating factor (GM-CSF). We have identified three homeobox genes, HOX A5, HOX B6, and HOX B7, which are expressed during early myelopoiesis. Treating bone marrow cells with antisense oligodeoxynucleotides to HOX A5 resulted in inhibition of granulocytic/monocytic hematopoiesis and increased the generation of erythroid progenitors. Also, overexpression of HOX A5 inhibited erythroid differentiation of the K562 cell line. Based on these observations, we propose that HOX A5 functions as an important regulator of hematopoietic lineage determination and maturation.


Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3620-3628 ◽  
Author(s):  
H Naora ◽  
IG Young

Abstract The mechanisms that regulate the mRNA levels of interleukin-5 (IL-5) were compared with those regulating the mRNA levels of two other coordinately expressed lymphokines in the murine T lymphoma EL4.23. Our results indicate that IL-5 mRNA levels are independently regulated from those of IL-2 and granulocyte-macrophage colony-stimulating factor (GM- CSF) mRNAs. The induction of IL-5 mRNA by phorbol 12-myristate 13- acetate (PMA) stimulation was found to be cyclosporin A-resistant, in contrast to the induction of IL-2 and GM-CSF mRNAs. Although the three lymphokine mRNAs were not detected in unstimulated cells by Northern blot analysis, the GM-CSF gene was found by nuclear run-off analysis to be constitutively transcribed. However, the IL-2 and IL-5 genes were transcriptionally inactive in the absence of PMA stimulation. The induction of IL-5 mRNA by PMA stimulation primarily involved increased transcriptional activity. In contrast, GM-CSF mRNA induction predominantly involved enhanced mRNA stability. Both transcriptional and mRNA stabilization mechanisms appeared to regulate IL-2 mRNA induction. The activation of IL-2 and IL-5 gene transcription was dependent on de novo protein synthesis. Cellular treatment with cycloheximide enhanced IL-2 gene transcription once activation was initiated, implicating the involvement of a labile repressor(s). Furthermore, IL-5 mRNA was more stable than IL-2 and GM-CSF mRNAs. These latter two species were stabilized by cycloheximide, suggesting that a labile mechanism may regulate their degradation.


Blood ◽  
1998 ◽  
Vol 92 (3) ◽  
pp. 778-783 ◽  
Author(s):  
Birgit Dibbert ◽  
Isabelle Daigle ◽  
Doris Braun ◽  
Corinna Schranz ◽  
Martina Weber ◽  
...  

Eosinophils are potent inflammatory cells involved in allergic reactions. Inhibition of apoptosis of purified eosinophils by certain cytokines has been previously shown to be an important mechanism causing tissue eosinophilia. To elucidate the role of Bcl-2 family members in the inhibition of eosinophil apoptosis, we examined the expression of the known anti-apoptotic genes Bcl-2, Bcl-xL, and A1, as well as Bax and Bcl-xS, which promote apoptosis in other systems. We show herein that freshly isolated human eosinophils express significant amounts of Bcl-xL and Bax, but only little or no Bcl-2, Bcl-xS, or A1. As assessed by reverse transcription-polymerase chain reaction, immunoblotting, flow cytometry, and immunocytochemistry, we show that spontaneous eosinophil apoptosis is associated with a decrease in Bcl-xL mRNA and protein levels. In contrast, stimulation of the cells with granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-5 (IL-5) results in maintenance or upregulation of Bcl-xL mRNA and protein levels. Moreover, Bcl-2 protein is not induced by GM-CSF or IL-5 in purified eosinophils. Bcl-2 protein is also not expressed in tissue eosinophils as assessed by immunohistochemistry using two different eosinophilic tissue models. Furthermore, Bcl-xL antisense but not scrambled phosphorothioate oligodeoxynucleotides can partially block the cytokine-mediated rescue of apoptotic death in these cells. These data suggest that Bcl-xL acts as an anti-apoptotic molecule in eosinophils. © 1998 by The American Society of Hematology.


Blood ◽  
1999 ◽  
Vol 94 (6) ◽  
pp. 1943-1951 ◽  
Author(s):  
Q. Sun ◽  
K. Jones ◽  
B. McClure ◽  
B. Cambareri ◽  
B. Zacharakis ◽  
...  

Human interleukin-5 (IL-5), granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-3 are eosinophilopoietic cytokines implicated in allergy in general and in the inflammation of the airways specifically as seen in asthma. All 3 cytokines function through cell surface receptors that comprise a ligand-specific  chain and a shared subunit (βc). Although binding of IL-5, GM-CSF, and IL-3 to their respective receptor  chains is the first step in receptor activation, it is the recruitment of βc that allows high-affinity binding and signal transduction to proceed. Thus, βc is a valid yet untested target for antiasthma drugs with the added advantage of potentially allowing antagonism of all 3 eosinophil-acting cytokines with a single compound. We show here the first development of such an agent in the form of a monoclonal antibody (MoAb), BION-1, raised against the isolated membrane proximal domain of βc. BION-1 blocked eosinophil production, survival, and activation stimulated by IL-5 as well as by GM-CSF and IL-3. Studies of the mechanism of this antagonism showed that BION-1 prevented the high-affinity binding of125I–IL-5, 125I–GM-CSF, and125I–IL-3 to purified human eosinophils and that it bound to the major cytokine binding site of βc. Interestingly, epitope analysis using several βc mutants showed that BION-1 interacted with residues different from those used by IL-5, GM-CSF, and IL-3. Furthermore, coimmunoprecipitation experiments showed that BION-1 prevented ligand-induced receptor dimerization and phosphorylation of βc, suggesting that ligand contact with βc is a prerequisite for recruitment of βc, receptor dimerization, and consequent activation. These results demonstrate the feasibility of simultaneously inhibiting IL-5, GM-CSF, and IL-3 function with a single agent and that BION-1 represents a new tool and lead compound with which to identify and generate further agents for the treatment of eosinophil-dependent diseases such as asthma.


2018 ◽  
Vol 36 (4_suppl) ◽  
pp. 386-386 ◽  
Author(s):  
Robin Kate Kelley ◽  
Emily Mitchell ◽  
Spencer Behr ◽  
Jimmy Hwang ◽  
Bridget Keenan ◽  
...  

386 Background: The efficacy of immune checkpoint inhibition (CPI) has not been established in ABC. GM-CSF modulates immune effector cells and has demonstrated safety and improved survival (OS) in combination with ipilimumab in melanoma. This phase 2 trial aims to evaluate the efficacy and safety of PEM in combination with GM-CSF in ABC. Methods: Design: Simon’s 2-stage. Key eligibility: ABC with progression/intolerance on ≥ 1 standard therapy, no prior CPI, bilirubin ≤1.5xULN. Treatment: PEM 200 mg IV Q21 days plus 2 cycles of GM-CSF 250 µg SC D1-14 Q21 days in cycles 2 and 3 (Stage 1 Safety Cohort) or in cycles 1 and 2 (Stage 2). Endpoints: 1◦: Progression-free survival at 6 months (PFS6) with H0 25% vs. H1 50%. Key 2◦: Safety, overall response rate (ORR) and duration (DOR), OS, PD-L1 expression. Exploratory: PBMC and tumor immune cell profiles, tumor genotype, microsatellite (in)stability (MSI or MSS). Results: Accrual has completed with 27 patients (pts) enrolled 5/2016-6/2017: F/M 13/14; median age 61 (range 37-77); intrahepatic 19 (70%), extrahepatic 7 (26%), mixed 1 (4%) cholangiocarcinoma; stage IVA/B 85%, II/III 15%; median prior therapies 2 (range 1-6). Adverse events (AE): Related grade(Gr) ≥3 AE occurred in 4/27 (15%) pts including immune-related (ir)AE of Gr4 diabetes mellitus and Gr3 thrombocytopenia in 1 pt each. Gr≤2 irAE in ≥5% were: arthralgia (33%), dry eye/mouth (15%), hyperthyroid/thyroiditis (15%), hypothyroid (15%), neuropathy (11%), rash (11%), and adrenal insufficiency (7%). Steroids were required in 3/27 (11%) pts. Disposition: 19 pts removed for PD, 1 for Gr2 irAE; 7 pts remain active on treatment. Median time on treatment: 6 cycles (range 2-22+). Best response by RECIST 1.1: Partial response (PR) in 5/24 (21%) evaluable pts (1 MSI, 4 MSS); minor regression and ≥50% CA 19-9 decline in 2 additional MSS pts for 11+ and 16+ months. PBMC analyses show changes in expression of activating and inhibitory markers including PD-1 on various immune cell populations. Conclusions: PEM plus induction GM-CSF is safe and tolerable in ABC. Durable radiographic and tumor marker responses including MSS pts warrant further study. PFS6, OS, and correlative analyses are ongoing. Clinical trial information: NCT02703714.


1998 ◽  
Vol 118 (4) ◽  
pp. 490-495 ◽  
Author(s):  
Erin D. Wright ◽  
Saul Frenkiel ◽  
Khalid Al-Ghamdi ◽  
Omar Ghaffar ◽  
Peter Small ◽  
...  

Chronic sinusitis and its associated eosinophilic infiltrate are believed to be mediated, at least in part, by the upregulation of Th-2 cytokines, including interleukin-4, interleukin-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF). Interleukin-4 is involved in IgE production and in eosinophil recruitment through upregulation of vascular cell adhesion molecule-1. Interleukin-5 and GM-CSF are involved in eosinophil growth and survival. The aim of this study was to investigate the expression of receptors for these cytokines in the sinus mucosa of subjects with chronic sinusitis. Using the technique of in situ hybridization to detect specific cytokine receptor messenger RNA, we studied the sinus mucosa of subjects with nonallergic chronic sinusitis, subjects with allergic chronic sinusitis, subjects with allergic chronic sinusitis treated with topical steroids, and normal controls. Our data demonstrate higher expression of interleukin-4 receptor in subjects with allergic chronic sinusitis than in controls ( p <0.001) and higher expression of interleukin-5 receptor in both subjects with nonallergic chronic sinusitis and subjects with allergic chronic sinusitis than in controls ( p <0.001, p <0.001). The expression of interleukin-4 receptor and interleukin-5 receptor was higher in subjects with allergic chronic sinusitis than in subjects with nonallergic chronic sinusitis ( p <0.001). GM-CSF receptor expression was also found to be higher in subjects with allergic chronic sinusitis and subjects with nonallergic chronic sinusitis than in controls ( p <0.001, p <0.001). In contrast to interleukin-4 receptor and interleukin-5 receptor, however, expression of GM-CSF receptor was higher in subjects with non-allergic chronic sinusitis than in subjects with allergic chronic sinusitis ( p <0.001). In subjects with allergic chronic sinusitis treated with topical corticosteroids, the expression of interleukin-4 receptor and interleukin-5 receptor messenger RNA levels was significantly lower than levels in patients with allergic chronic sinusitis who were not taking topical steroids ( p <0.001, p <0.001). Steroid treatment had no effect on GM-CSF receptor messenger RNA expression. In conclusion, our data support a role for Th-2 cytokine receptors in the pathophysiology of chronic sinusitis. Further, our data lend support to the theory that differential activation of distinct cytokine pathways mediates inflammation in chronic sinusitis depending on whether there is associated allergy. Finally, treatment with topical corticosteroids has been demonstrated in chronic sinusitis to downregulate receptors for interleukin-4 and interleukin-5.


Author(s):  
Neha Akkad ◽  
Yang Jiang ◽  
Daniel Shin

Significant leucocytosis in the setting of an underlying malignancy may be attributed to several causes and is not uncommon; however, extreme leucocytosis (>50×109 cells/l) and hypereosinophilia is less common and may represent a paraneoplastic syndrome. The underlying mechanism is thought to be bone marrow stimulation by tumour-produced cytokines, most notably interleukin-5 (IL-5) and granulocyte-macrophage colony-stimulating factor (GM-CSF). This paraneoplastic syndrome is likely reflective of extensive disease and dissemination, and options for treatment are limited but include tumour resection, corticosteroids and hydroxyurea. In this report, we discuss an unusual case of known stage III lung adenocarcinoma presenting with an ischaemic stroke and extreme leucocytosis and hypereosinophilia. 


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