Characterization of Siglec-8 Expression on Lavage Cells after Segmental Lung Allergen Challenge

Johansson, Mats W.; Kelly, Elizabeth A.; Nguyen, Christopher L.; Jarjour, Nizar N.; Bochner, Bruce S.

doi:10.1159/000488951

Cited by 21 publications

(20 citation statements)

References 38 publications

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“…For example, the former mice displayed Siglec-8 expression on about 15% basophils besides mast cells, consistent with what has been reported with other mouse lines derived using the CPA3-Cre strain [21]. This is similar to the observation that Siglec-8 was seen in a small percentage of human basophils [2,4]. Although Mcpt5 is a mast cell-specific protease, Mcpt5 is not expressed in all mast cells [24], so it was not unexpected that Siglec-8 was not expressed on all mast cells in the Mcpt5-Siglec-8 mice.…”

Section: Discussionsupporting

confidence: 89%

“…Sialic acid immunoglobulin-like lectin 8 (Siglec-8) is a member of the CD33 subfamily of glycan receptors called Siglecs. Siglec-8 is unique in its expression on human eosinophils, mast cells, and basophils, which are important innate immune effector cells in allergy, asthma, and other type 2 disorders [1,2,3,4]. Polymorphisms in the Siglec-8 gene are associated with asthma susceptibility [5].…”

Section: Introductionmentioning

confidence: 99%

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Mast Cell-Specific Expression of Human Siglec-8 in Conditional Knock-in Mice

Wei

Chhiba

Zhang

et al. 2018

IJMS

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Sialic acid-binding Ig-like lectin 8 (Siglec-8) is expressed on the surface of human eosinophils, mast cells, and basophils—cells that participate in allergic and other diseases. Ligation of Siglec-8 by specific glycan ligands or antibodies triggers eosinophil death and inhibits mast cell degranulation; consequences that could be leveraged as treatment. However, Siglec-8 is not expressed in murine and most other species, thus limiting preclinical studies in vivo. Based on a ROSA26 knock-in vector, a construct was generated that contains the CAG promoter, a LoxP-floxed-Neo-STOP fragment, and full-length Siglec-8 cDNA. Through homologous recombination, this Siglec-8 construct was targeted into the mouse genome of C57BL/6 embryonic stem (ES) cells, and chimeric mice carrying the ROSA26-Siglec-8 gene were generated. After cross-breeding to mast cell-selective Cre-recombinase transgenic lines (CPA3-Cre, and Mcpt5-Cre), the expression of Siglec-8 in different cell types was determined by RT-PCR and flow cytometry. Peritoneal mast cells (dual FcεRI+ and c-Kit+) showed the strongest levels of surface Siglec-8 expression by multicolor flow cytometry compared to expression levels on tissue-derived mast cells. Siglec-8 was seen on a small percentage of peritoneal basophils, but not other leukocytes from CPA3-Siglec-8 mice. Siglec-8 mRNA and surface protein were also detected on bone marrow-derived mast cells. Transgenic expression of Siglec-8 in mice did not affect endogenous numbers of mast cells when quantified from multiple tissues. Thus, we generated two novel mouse strains, in which human Siglec-8 is selectively expressed on mast cells. These mice may enable the study of Siglec-8 biology in mast cells and its therapeutic targeting in vivo.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Mast Cell-Specific Expression of Human Siglec-8 in Conditional Knock-in Mice

Wei

Chhiba

Zhang

et al. 2018

IJMS

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“…As eosinophils have not been characterized by flow cytometry in human fat, we first determined the repertoire of antibodies required to successfully sort eosinophils. Our gating strategy relied on antibodies used previously for identification of eosinophils in blood through exclusion of CD14 and CD16 and inclusion of Siglec-8 and CD66b 15 , 30 , 31 (Fig. 2 a).…”

Section: Resultsmentioning

confidence: 99%

A FACS-based approach to obtain viable eosinophils from human adipose tissue

Hernandez

Tew

et al. 2020

Sci Rep

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Eosinophils have been widely investigated in asthma and allergic diseases. More recently, new insights into the biology of these cells has illustrated eosinophils contribute to homeostatic functions in health such as regulation of adipose tissue glucose metabolism. Human translational studies are limited by the difficulty of obtaining cells taken directly from their tissue environment, relying instead on eosinophils isolated from peripheral blood. Isolation techniques for tissue-derived eosinophils can result in unwanted cell or ribonuclease activation, leading to poor cell viability or RNA quality, which may impair analysis of effector activities of these cells. Here we demonstrate a technique to obtain eosinophils from human adipose tissue samples for the purpose of downstream molecular analysis. From as little as 2 g of intact human adipose tissue, greater than 10 4 eosinophils were purified by fluorescence-activated cell sorting (FACS) protocol resulting in ≥ 99% purity and ≥ 95% viable eosinophils. We demonstrated that the isolated eosinophils could undergo epigenetic analysis to determine differences in DNA methylation in various settings. Here we focused on comparing eosinophils isolated from human peripheral blood vs human adipose tissue. Our results open the door to future mechanistic investigations to better understand the role of tissue resident eosinophils in different context.

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“…In addition, the levels of Siglec-8 remain stable on blood eosinophils after patients received treatment with prednisone or imatinib, despite significant decreases in absolute eosinophil counts [ 16 ]. Airway tissue eosinophils from bronchoalveolar lavage and sputum from subjects with asthma have similar levels of surface Siglec-8 as their blood eosinophils [ 17 , 18 ]. Likewise, Siglec-8 expression is comparable on gastrointestinal tissue eosinophils and mast cells from patients with EoE or EG, compared to tissues from control subjects without these diseases, despite elevated numbers and an activated phenotype of these cells in these diseases [ 19 ].…”

Section: Expression Pattern Of Siglec-8mentioning

confidence: 99%

Discovery, Function, and Therapeutic Targeting of Siglec-8

Youngblood

Leung

Falahati

et al. 2020

Cells

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Siglecs (sialic acid-binding immunoglobulin-like lectins) are single-pass cell surface receptors that have inhibitory activities on immune cells. Among these, Siglec-8 is a CD33-related family member selectively expressed on human mast cells and eosinophils, and at low levels on basophils. These cells can participate in inflammatory responses by releasing mediators that attract or activate other cells, contributing to the pathogenesis of allergic and non-allergic diseases. Since its discovery in 2000, initial in vitro studies have found that the engagement of Siglec-8 with a monoclonal antibody or with selective polyvalent sialoglycan ligands induced the cell death of eosinophils and inhibited mast cell degranulation. Anti-Siglec-8 antibody administration in vivo to humanized and transgenic mice selectively expressing Siglec-8 on mouse eosinophils and mast cells confirmed the in vitro findings, and identified additional anti-inflammatory effects. AK002 (lirentelimab) is a humanized non-fucosylated IgG1 antibody against Siglec-8 in clinical development for mast cell- and eosinophil-mediated diseases. AK002 administration has safely demonstrated the inhibition of mast cell activity and the depletion of eosinophils in several phase 1 and phase 2 trials. This article reviews the discovery and functions of Siglec-8, and strategies for its therapeutic targeting for the treatment of eosinophil- and mast cell-associated diseases.

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Characterization of Siglec-8 Expression on Lavage Cells after Segmental Lung Allergen Challenge

Cited by 21 publications

References 38 publications

Mast Cell-Specific Expression of Human Siglec-8 in Conditional Knock-in Mice

Mast Cell-Specific Expression of Human Siglec-8 in Conditional Knock-in Mice

A FACS-based approach to obtain viable eosinophils from human adipose tissue

Discovery, Function, and Therapeutic Targeting of Siglec-8

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