岩藻聚糖通过上调 Claudin-1 的表达增强肠道屏障功能。
Fucoidan enhances intestinal barrier function by upregulating the expression of claudin-1.
机构信息
Atsushi Iraha, Akira Hokama, Kazuto Kishimoto, Tetsuo Hirata, Futoshi Higa, Masao Tateyama, Jiro Fujita, Department of Infectious, Respiratory, and Digestive Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan.
出版信息
World J Gastroenterol. 2013 Sep 7;19(33):5500-7. doi: 10.3748/wjg.v19.i33.5500.
AIM
To evaluate the protective effects of fucoidan on oxidative stress-induced barrier disruption in human intestinal epithelial cells.
METHODS
In Caco-2 cell monolayer models, the disruption of barrier function by oxidative stress is mediated by H₂O₂. The integrity of polarized Caco-2 cell monolayers was determined by measuring the transepithelial resistance (TER) and permeability was estimated by measuring the paracellular transport of FITC-labeled 4-kDa dextran (FD4). The protective effects of fucoidan on epithelial barrier functions on polarized Caco-2 cell monolayers were evaluated by TER and FD4 flux. The expression of tight junction (TJ) proteins was assessed using reverse-transcription polymerase chain reaction (RT-PCR) and immunofluorescence staining.
RESULTS
Without H₂O₂ treatment, fucoidan significantly increased the TER compared to control (P < 0.05), indicating a direct enhancement of intestinal epithelial barrier function. Next, H₂O₂ disrupted the epithelial barrier function in a time-dependent manner. Fucoidan prevented the H₂O₂-induced destruction in a dose-dependent manner. Fucoidan significantly decreased H₂O₂-induced FD4 flux (P < 0.01), indicating the prevention of disruption in paracellular permeability. RT-PCR showed that Caco-2 cells endogenously expressed claudin-1 and -2, and occludin and that H₂O₂ reduced the mRNA expression of these TJ proteins. Treatment with fucoidan attenuated the reduction in the expressions of claudin-1 and claudin-2 but not occludin. Immunofluorescence staining revealed that the expression of claudin-1 was intact and high on the cell surface. H₂O₂ disrupted the integrity of claudin-1. Treatment with fucoidan dramatically attenuated the expression of claudin-1.
CONCLUSION
Fucoidan enhanced intestinal epithelial barrier function by upregulating the expression of claudin-1. Thus, fucoidan may be an appropriate therapy for the treatment of inflammatory bowel diseases.
目的
评估岩藻聚糖硫酸酯对人肠道上皮细胞氧化应激诱导的屏障破坏的保护作用。
方法
在 Caco-2 细胞单层模型中，通过 H₂O₂介导氧化应激对屏障功能的破坏。通过测量跨上皮电阻（TER）来确定极化 Caco-2 细胞单层的完整性，通过测量 FITC 标记的 4 kDa 葡聚糖（FD4）的旁细胞转运来估计通透性。通过 TER 和 FD4 通量评估岩藻聚糖硫酸酯对极化 Caco-2 细胞单层上皮屏障功能的保护作用。使用逆转录聚合酶链反应（RT-PCR）和免疫荧光染色评估紧密连接（TJ）蛋白的表达。
结果
没有 H₂O₂处理，岩藻聚糖硫酸酯与对照相比显著增加 TER（P < 0.05），表明直接增强肠道上皮屏障功能。接下来，H₂O₂以时间依赖性方式破坏上皮屏障功能。岩藻聚糖硫酸酯以剂量依赖性方式防止 H₂O₂诱导的破坏。岩藻聚糖硫酸酯显著降低 H₂O₂诱导的 FD4 通量（P < 0.01），表明对旁通透性破坏的预防。RT-PCR 显示 Caco-2 细胞内源性表达 Claudin-1 和 Claudin-2，以及 Occludin，并且 H₂O₂降低这些 TJ 蛋白的 mRNA 表达。岩藻聚糖硫酸酯处理减弱 Claudin-1 和 Claudin-2 的表达减少，但不影响 Occludin。免疫荧光染色显示 Claudin-1 的表达完整且在细胞表面高表达。H₂O₂破坏 Claudin-1 的完整性。岩藻聚糖硫酸酯处理显著减弱 Claudin-1 的表达。
结论
岩藻聚糖硫酸酯通过上调 Claudin-1 的表达增强肠道上皮屏障功能。因此，岩藻聚糖硫酸酯可能是治疗炎症性肠病的合适疗法。
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