Airways exposure of bacterial superantigen SEB enhances bone marrow eosinophil population and facilitates its egress to blood and lung tissue.

Abstract

BACKGROUND:

Differentiation of bone marrow eosinophils (BM-EO) and its trafficking to peripheral blood and respiratory mucosa are a hallmark of inflammatory diseases. Staphylococcal enterotoxin B (SEB) has been shown to aggravate airways eosinophilic inflammation. This study aimed to investigate the effects of mouse airways SEB exposure on BM-EO population, as well as its adhesive properties and release of cytokines/chemokines that orchestrate BM-EO trafficking to lungs.

METHODS:

Male BALB/c mice were intranasally exposed to SEB (1 μg), and at 4, 16, 24 and 48 h thereafter, bone marrow (BM), circulating blood and bronchoalveolar lavage (BAL) fluid were collected. Levels of cytokines/chemokines and expressions of VLA-4 and CCR3 in BM were evaluated. Adhesion of BM to ICAM-1 and VCAM-1 were also evaluated.

RESULTS:

SEB exposure promoted a marked eosinophil influx to BAL at 16 and 24 h after exposure, which was accompanied by significant increases in counts of immature (16 h) and mature (4 to 48 h) forms of eosinophil in BM, along with blood eosinophilia (16 h). In BM, higher levels of eotaxin, IL-5, IL-4, IL-3 and IL-7 were detected at 16 to 48 h. SEB also significantly increased CCR3 expression and calcium levels in BM-EO, and enhanced the cell adhesion to ICAM-1 (24 h) and ICAM-1 (48 h).

CONCLUSION:

Airways SEB exposure increases the number of eosinophils in BM by mechanisms involving a network of cytokine and chemokine release, facilitating the BM-EO adhesion to ICAM-1 and VCAM-1 to gain access to the peripheral blood and lung tissues.

• Authors: A S Pinheiro-Torres, A P Ferreira-Duarte, W M Takeshita, V O Gushiken, I A Roncalho-Buck, G F Anhê, E Antunes, I A DeSouza
• Journal: Life sciences (Life Sci) Vol. 264 Pg. 118685 (Jan 01 2021) ISSN: 1879-0631 [Electronic] Netherlands
• PMID: 33137369 (Publication Type: Journal Article)
• Copyright: Copyright © 2020. Published by Elsevier Inc.

Chemical References

• Enterotoxins
• enterotoxin B, staphylococcal

Topics

• Administration, Intranasal (methods)
• Animals
• Bone Marrow (metabolism, microbiology)
• Bronchoalveolar Lavage Fluid (microbiology)
• Enterotoxins (administration & dosage, blood, metabolism)
• Eosinophils (metabolism, microbiology)
• Lung (metabolism, microbiology)
• Male
• Mice
• Mice, Inbred BALB C
• Nasal Absorption (physiology)
• Staphylococcus aureus (metabolism)