Asthma-related inflammation promotes lung metastasis of breast cancer cells through CCL11–CCR3 pathway

Background: Mechanisms that preclude lung metastasis are still barely understood. The possible consequences of allergic airways inflammation on cancer dissemination were studied in a mouse model of breast cancer. Methods: Balb/c mice were immunized and daily exposed to ovalbumin (OVA) from day 21. They were subcutane- ously injected with 4T1 mammary tumor cells on day 45 and sacrificed on day 67. Lung metastases were measured by biophotonic imaging (IVIS 200 Imaging System) and histological measurement of tumor area (Cytomine software). Effects of CCL11 were assessed in vivo by intratracheal instillations of recCCL11 and in vitro using Boyden chambers. CCR3 expression on cell surface was assessed by flow cytometry. Results: The extent of tumor metastases was significantly higher in lungs of OVA-exposed mice and increased levels of CCL11 expression were measured after OVA exposure. Migration of 4T1 cells and neutrophils was stimulated in vitro and in vivo by recCCL11. 4T1 cells and neutrophils express CCR3 as shown by flow cytometry and a selective CCR3 antagonist (SB-297006) inhibited the induction of 4T1 cells migration and proliferation in response to recCCL11. Conclusions: Allergic inflammation generated by exposure to allergens triggers the implantation of metastatic cells from primary breast tumor into lung tissues plausibly in a CCL11–CCR3-dependent manner. This indicates that asthma related inflammation in lungs might be a risk factor for lung metastasis in breast cancer patients.Peer reviewe

Methods to Detect Neutrophil Extracellular Traps in Asthma.

peer reviewedNeutrophil extracellular traps (NETs) have the ability to regulate many aspects of asthma pathology. NETs can be detected either in bronchoalveolar lavage fluids (BALF) or in lung biopsies. Here, we describe methods to quantify NETs in BALF, namely the quantification of cell-free DNA, or of myeloperoxidase (MPO) or neutrophil elastase (NE) complexed with cell-free DNA. We also explain how to detect NETs in lung biopsies by two distinct techniques. The first technique is based on quantification of the citrullinated form of histone 3 (Cit-H3 , a specific component of NET) by western blot on tissue protein extracts. The second technique is based on the visualization of extracellular structures composed of MPO co-localizing with Cit-H3 in tissue sections by confocal microscopy. Finally, we describe a method allowing for quantification of NET volume in lung sections

Fonctions divergentes entre les fluides périviscéraux et hydrovasculaires en cas de stress immunologique chez les holothuries (Holothuria forskali)

editorial reviewedEchinoderms have two main coelomic cavities in their body plan: the general perivisceral cavity containing the different organs and the hydrovascular cavity constituting a unique vascular system also known as the water vascular system. These two cavities are filled with a fluid whose composition is close to that of seawater, but which contains a large amount of metabolites and cells. These cells are called coelomocytes and constitute the main actor of echinoderm immunity. Different cell types have been described based on morphological criteria; it appears that sea cucumbers show the greatest diversity among the five classes of echinoderms at six to seven different types. While the immune response of perivisceral coelomocytes has already been studied in different species, the immune response of hydrovascular coelomocytes remains understudied and the differences in their immune response have not been investigated yet. In the present study, we investigated the transcriptomic response of coelomocytes to injections of lipopolysaccharide (LPS) – a molecule that mimics a bacterial infection – in the sea cucumber Holothuria forskali. Coelomocytes from both fluids were studied distinctly to compare their immune response. In addition, we attempted to correlate gene expression with the proportion of different coelomocyte types in each fluid by counting the cells (Fig. 1). Our results revealed 17,646 differentially expressed genes (DEGs) between control and LPS-injected individuals (by considering both fluids) and 5524 and 6420 DEGS specific to the perivisceral and hydrovascular fluid, respectively. Regarding the comparison of the two fluids, 2853 genes were DEGs when considering all individuals (i.e., control and LPS-injected individuals). Interestingly, the same analysis resulted in only 179 DEGs in control individuals but in 2773 DEGs in stressed individuals. These results suggest that in immunoquiescent conditions, the coelomocytes from both fluids have a similar function but that this function tends to change following the immunological stress. Furthermore, this change coincides with an increase in the concentration of hemocytes as a result of immunological stress that occurs only in the hydrovascular fluid. Finally, the functional annotation of DEGs offers precious information about the specific functions of coelomocytes in both fluids. This research raises interesting questions about the function of the hydrovascular system and coelomocytes and provides valuable data for comparative immunology

Neutrophil extracellular traps infiltrate the lung airway, interstitial, and vascular compartments in severe COVID-19

Infection with SARS-CoV-2 is causing a deadly and pandemic disease called coronavirus disease-19 (COVID-19). While SARS-CoV-2-triggered hyperinflammatory tissue-damaging and immunothrombotic responses are thought to be major causes of respiratory failure and death, how they relate to lung immunopathological changes remains unclear. Neutrophil extracellular traps (NETs) can contribute to inflammation-associated lung damage, thrombosis, and fibrosis. However, whether NETs infiltrate particular compartments in severe COVID-19 lungs remains to be clarified. Here we analyzed postmortem lung specimens from four patients who succumbed to COVID-19 and four patients who died from a COVID-19-unrelated cause. We report the presence of NETs in the lungs of each COVID-19 patient. NETs were found in the airway compartment and neutrophil-rich inflammatory areas of the interstitium, while NET-prone primed neutrophils were present in arteriolar microthrombi. Our results support the hypothesis that NETs may represent drivers of severe pulmonary complications of COVID-19 and suggest that NET-targeting approaches could be considered for the treatment of uncontrolled tissue-damaging and thrombotic responses in COVID-19. © 2020 Radermecker et al. This article is distributed under the terms of an Attribution-Noncommercial-Share Alike-No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms/). After six months it is available under a Creative Commons License (Attribution-Noncommercial-Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/)