The Suppressive Effect of Quercetin on Toll-Like Receptor 7-Mediated Activation in Alveolar Macrophages

Pharmacology
Masahiro YasuiTsutomu Kawabe

Abstract

Respiratory viral infections that cause chronic airway and lung disease can result in the activation of the innate immune response. Alveolar macrophages (AMs), one of the first lines of defense in the lung, are abundantly located in alveoli and the respiratory tract. Flavonoids found in fruits and vegetables exhibit cytoprotective effects on various cell types. In this study, we investigated the effect of quercetin on activation of AMs that had been exposed to imiquimod, a ligand of Toll-like receptor (TLR) 7. In both a mouse AM cell line (AMJ2-C11 cells) and mouse bronchoalveolar fluid cells, we demonstrated that quercetin attenuated TLR7-induced the expression of TNF-α and IL-6. In AMJ2-C11 cells, quercetin also attenuated the TLR7-induced CD40 expression; attenuated the translocation of p65; induced translocation of Nrf2 from cytosol to nucleus; and induced heme oxygenase (HO)-1 expression. Notably, tin protoporphyrin IX (SnPP), an inhibitor of HO-1, also attenuated TLR7-induced transcription of the TNF-α and IL-6 genes, suggesting that the effect of quercetin is mediated by HO-1. These results suggest that dietary supplementation with quercetin may have efficacy in the treatment of respiratory viral infection.

Citations

Jul 1, 2018·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Zhi-Peng LiQuan-Bin Han
May 14, 2020·Immunopharmacology and Immunotoxicology·Tomoshi SugiyamaTsutomu Kawabe
Sep 16, 2017·Frontiers in Pharmacology·Kai-Jun GouYan Qu
Jun 6, 2021·The Journal of Nutritional Biochemistry·Paula R AugustiTatiana Emanuelli

❮ Previous
Next ❯

Related Concepts

Related Feeds

Asthma

This feed focuses in Asthma in which your airways narrow and swell. This can make breathing difficult and trigger coughing, wheezing and shortness of breath.

Allergy and Asthma

Allergy and asthma are inflammatory disorders that are triggered by the activation of an allergen-specific regulatory t cell. These t cells become activated when allergens are recognized by allergen-presenting cells. Here is the latest research on allergy and asthma.