Flavonoids of Sophora flavescens promote autophagy and anti-inflammatory activities in Bacillus Calmette-Guérin-stimulated murine macrophages
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摘要Tuberculosis (TB) is a highly infectious air-borne disease that remains one of the major global health problems. Conventional treatments such as antibiotics isoniazid, rifampicin, and pyrazinamide often cause undesirahle side effects, and Mycobacterium bovis attenuated Bacilli Calmette-Guerin (BCG) vaccine offer limited protection. Adjunct therapy may be necessary to lessen recovery time and improve clearance of bacteria. Flavonoids present in medicinal herb Sophora Flavescens has been shown to exhibit anti-inflammatory and bactericidal activities. To further investigate the anti-inflammatory mechanisms of FSF in TB infection, molecular and cellular characterization of FSF promoting autophagy in BCG-infected macrophages is examined.

Murine alveolar macrophage cell line MH-S cells and primary murine peritoneal cells were stimulated in vitro with heat-inactivated BCG and treated with Flavonoids of Sophora Flavescens (FSF), with or without autophagy inhibitor Bafilomycin A1. Autophagy-related gene expression, cytokine release was measured with quantitative PCR and Milliplex assay, respectively, to assess the extent of autophagy activation in BCG-simulated macrophages. Autophagy-related proteins and cellular materials were measured by Western blot, flow cytometry and fluorescent microscopy. Results Autophagy-related proteins LC3 and P62 were upregulated and autophagy-related genes AMBRA1, FBXL20 and RAB24 were upregulated significantly following treatment with FSF. Pro-inflammatory cytokines such as CCL5 and IL-6 were suppressed following treatment of FSF in BCG stimulated macrophages. This effect was observed in both primary murine cells and MH-S cell line. Addition of autophagy inhibitor has resulted in enhancement or restoration in gene expression after FSF treatment. Autophagolysosome formation was observed with FSF treatment on BCG-stimulated MH-S but inhibited at a higher concentration.

It has been shown that FSF actively modulates immune processes through suppressing the inflammatory response in MH-S cells activated by BCG. Upregulation of autophagy associated proteins and gene expression by FSF demonstrates its induction of autophagy and possibly bacterial clearance. However, this only occurs at specific environments, which is indicative of a highly sensitive and controlled response. The regulation of autophagy may lead to subsequent suppression of pro-inflammatory cytokines of FSF-treated BCG-stimulated macrophages.

FSF may be used as an adjunctive agent to aid bacterial clearance by increasing cell survival through autophagy and reducing inflammation in TB infection. Further work such as using human cells is necessary to further evaluate the functional applications and mechanisms between FSF, inflammation and autophagy in TB infection.
著者Kan Ling Yu Lea, Liu Dehua, Chan Chung Lap, Leung Ping Chung, Wong Chun Kwok
會議名稱Hong Kong Society for Immunology (HKSI) Annual Meeting 2019
會議地點University of Hong Kong

上次更新時間 2021-25-03 於 13:12