液化澱粉芽孢桿菌胞外多醣提升腸道上皮細胞的保護性功能

Bacillus amyloliquefaciens exopolysaccharides promote the protective functions of intestinal epithelial cells

曾建銘(Tseng Chien Ming)

指導教授 ： 鄭雪玲

國立屏東科技大學/農學院/生物科技系/碩士(2022年)

https://doi.org/10.6346/NPUST202200078

摘要

益生菌有健胃整腸、抑制腸道發炎，以及促進腸道健康的功能，但是機制仍不完全清楚。於前期研究中，液化澱粉芽孢桿菌(Bacillus amyloliquefaciens) amy-1分泌的胞外多醣 (exopolysaccharides；EPS)被發現有抗發炎的功能。於是本研究以人類腸道上皮細胞Caco-2為模型，分析amy-1 EPS提升腸道上皮細胞的保護性功能。方法是以脂多醣 (Lipopolysaccharides；LPS)作為正對照組，以EPS單獨或與LPS共同處理Caco-2細胞，分析是否促進腸道上皮細胞的保護性功能，並初步研究其分子機制。結果，EPS能夠促進Caco-2細胞分泌抗菌胜肽並促進Caco-2細胞的屏障功能(barrier function)，後者經分析認為與EPS促進occludin及zonula occludens-1等tight junction形成蛋白的表現有關。這些結果暗示EPS能提升腸道上皮細胞的抗菌能力及避免外來物質藉由細胞間隙進入身體的能力。EPS促進inducible nitric oxide synthase (iNOS), cyclooxygenase-2及interleukin-8的表現，暗示EPS可提升腸道上皮細胞的免疫相關活性。EPS活化nuclear factor erythroid 2–related factor 2 (Nrf2) / heme oxygenase-1 (HO-1) pathway，並且降低活性氧物種 (reactive oxygen species)生成量，暗示EPS可提升細胞的抗氧化能力，而這可能與EPS活化 mitogen activated protein kinases中的p38有關。但是當LPS存在時，EPS卻又抑制iNOS的表現，暗示能抑制LPS引起的發炎反應。綜合這些結果，認為EPS可以提升腸道上皮細胞的保護性功能。

關鍵字

exopolysaccharides ； Bacillus amyloliqufaciens ； Caco-2細胞 ； 腸道免疫力 ； 抗菌胜肽 ； barrier function ； p38 ； Nrf2/HO-1 pathway

並列摘要

Probiotics are beneficial to the digestive tract, can reduce intestinal inflammation, and promote the health of intestines, but the underlying mechanism is still unclear. The exopolysaccharides (EPS) of Bacillus amyloliqufaciens amy-1 were found to have anti-inflammatory effects. In this study, the human intestinal epithelial cell line Caco-2 was used as a model to investigate whether EPS can promte the protective functions of intestines. Caco-2 cells were treated with EPS or with lipopolysaccharides (LPS; positive control). Consequently, EPS increased the secretion of antimicrobial peptides from Caco-2 cells, and enhanced the barrier function of the cell. The latter was found to be associated with EPS-promoted expression of tight junction-forming proteins occludin and zonula occludens-1. These results suggest that EPS can improve the antibacterial activity and the ability to prevent foreign substances from entering the body through the intercellular space of intestinal epithelial cells. EPS promoted the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 and interleukin-8, suggesting that EPS can enhance the immune-related activity of intestinal epithelial cells. EPS activated the nuclear factor erythroid 2-related factor 2 (Nrf2) / heme oxygenase-1 (HO-1) pathway and reduced the production of reactive oxygen species, suggesting that EPS can enhance the antioxidant capacity of the cells, which may be related to the activation of EPS induced-p38 activation. However, in the presence of LPS, EPS inhibited the expression of iNOS, implying that EPS can inhibit LPS-induced inflammation. Taken together, EPS promote the protective functions of intestinal epithelial cells.

並列關鍵字

exopolysaccharides ； Bacillus amyloliqufaciens ； Caco-2 cells ； intestinal immunity ； antimicrobial peptides ； barrier function ； p38 ； Nrf2/HO-1 pathway

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