陆军军医大学学报 (Mar 2024)
Affinity test of 18 traditional Chinese medicine polysaccharides with Siglec-9 and their anti-inflammatory effects
Abstract
Objective To compare the affinity with sialic acid-binding immunoglobulin-like lectin-9 (Siglec-9) and anti-inflammatory effects of 18 traditional Chinese medicine polysaccharides in order to explore a new mechanism for the anti-inflammatory effects of these polysaccharides. Methods Aqueous alcohol precipitation was used to extract polysaccharides from 18 traditional Chinese medicines with different medicinal properties. Phenol sulfuric acid method was employed to detect the content of the polysaccharides, high performance liquid chromatography (HPLC) was utilized to measure the monosaccharide composition of the polysaccharides, and infrared spectroscopy was applied to detect the structure of the polysaccharides of Chinese medicines. The affinity of polysaccharide to Siglec-9 was detected by competitive ELISA, and the effects of the polysaccharides on LPS-induced inflammatory responses in macrophages and R848-induced NETosis in neutrophils were investigated. Primary cultured macrophages and neutrophils derived from myeloid-specific Siglec-E knockout mice (Lyz2-cre: Siglec-Eflox/flox) were used to further clarify the mechanism of the anti-inflammation of the polysaccharides. Results All these 18 traditional Chinese medicines had the content of polysaccharide over 55%, and mainly composed of mannose, glucose, galactose, arabinose and glucuronic acid, with different composition ratio of monosaccharide separately. Infrared spectroscopy revealed that there were typical polysaccharide absorption peaks in all 4 representative polysaccharides, and the polysaccharides from Bupleurum chinense and Dandelion had glucuronic acid structures. The affinities with Siglec-9 in the polysaccharides from Lycium barbarum and Astragalus showed no inhibitory effect on LPS-induced inflammatory responses in macrophages and R848-induced NETosis in neutrophils. While, Bupleurum chinense and dandelion polysaccharides presented strong affinities with Siglec-9 (P < 0.01), and exerted obvious inhibitory effect on above inflammatory reactions, but the anti-inflammatory effects were lost disappeared in the macrophages and neutrophils derived from Siglec-E conditional knockout mice. Conclusion The affinity between Chinese herbal polysaccharide and Siglec-9 has a possibility to be a potential novel pharmacological mechanism of the anti-inflammatory effects of traditional Chinese medicine.
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