Effect of Acinetobacter lwoffii on the modulation of macrophage activation and asthmatic inflammation

Abstract

Background Although lung macrophages are directly exposed to external stimuli, their exact immunologic roles in asthma are still largely unknown. The aim of this study was to investigate the anti‐asthmatic effect of Acinetobacter lwoffii in terms of lung macrophage modulation. Methods Six‐week‐old female BALB/c mice were sensitized and challenged with ovalbumin (OVA) with or without intranasal administration of A. lwoffii during the sensitization period. Airway hyperresponsiveness and inflammation were evaluated. Using flow cytometry, macrophages were subclassified according to their activation status. In the in vitro study, a murine alveolar macrophage cell line (MH‐S) treated with or without A. lwoffii before IL‐13 stimulation were analysed by quantitative RT‐PCR. Results In a murine asthma model, the number of inflammatory cells, including macrophages and eosinophils, decreased in mice treated with A. lwoffii (A. lwoffii/OVA group) compared with untreated mice (OVA group). The enhanced expression of MHCII in macrophages in the OVA group was decreased by A. lwoffii treatment. M2 macrophage subtypes were significantly altered. A. lwoffii treatment decreased CD11b+M2a and CD11b+M2c macrophages, which showed strong positive correlations with Th2 cells, ILC2 and eosinophils. In contrast, CD11b+M2b macrophages were significantly increased by A. lwoffii treatment and showed strong positive correlations with ILC1 and ILC3. In vitro, A. lwoffii down‐regulated the expression of M2 markers related but up‐regulated those related to M2b macrophages. Conclusions and Clinical Relevance Intranasal A. lwoffii exposure suppresses asthma development by suppressing the type 2 response via modulating lung macrophage activation, shifting M2a and M2c macrophages to M2b macrophages.

Biodiversity for resilience—What is needed for allergic children

“…Bacteria characterize best the differences in microbial communities and are not equal in their immunomodulating potential. For example, Acinetobacter species, both on human skin and on mice, are effective immunoregulators and associated with allergy and asthma risk 10‐12 . Maternal carriage of Prevotella copri during pregnancy decreases the offspring's risk of allergic disease and asthma 13 .…”

“…For example, Acinetobacter species, both on human skin and on mice, are effective immunoregulators and associated with allergy and asthma risk. [10][11][12] Maternal carriage of Prevotella copri during pregnancy decreases the offspring's risk of allergic disease and asthma. 13 In the gut, Morganella species has a potential causal effect on major depressive disorder.…”

Activating transcription factor-2 supports the antioxidant capacity and ability of human mesenchymal stem cells to prevent asthmatic airway inflammation

“…Asthma was induced in 6-week-old female BALB/c mice (JA Bio, Suwon, Korea) by sensitization with intraperitoneal injections of 100 µg of ovalbumin (OVA, Sigma-Aldrich) and 2 mg of aluminum hydroxide (Sigma-Aldrich) on Days 0 and 7, followed by allergen challenge via intranasal injection of 50 μg of OVA on Days 14, 15, 16, 21, 22, and 23, as reported previously 27 . After 17 days, 3 × 10 5 hUC-MSCs stably expressing a control (shCTR) or ATF2-specific (shATF2) shRNA construct were suspended in 100 µL of phosphate-buffered saline (PBS) and injected via the tail vein.…”

ILC2s expanded by exogenous IL-33 regulate CD45+CD11b+F4/80high macrophage polarization to alleviate hepatic ischemia-reperfusion injury

“…They can be activated by alarmins such as IL25, IL-33 after tissue damage (9,10) and play crucial roles in metabolic homeostasis, parasite infection and tissue repair through inducing type 2 inflammation (11). In asthma, the number of ILC2s have been shown to be positively correlated with the number of M2 macrophages in induced sputum from asthmatic patients (12), and the expression of M2 macrophage related genes can be induced in co-cultures of ILC2s and Alveolar Macrophages (13). ILC2s can be found in various locations and exert a number of different roles depending on their current surroundings.…”