Division of Traditional Chinese Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing 100193, P. R. China.
Food Funct. 2021 Mar 21;12(6):2715-2725. doi: 10.1039/d1fo00155h. Epub 2021 Mar 5.
The microvasculature endothelium accurately regulates the passage of molecules across the gut-vascular barrier (GVB), which plays an essential role in intestinal immunity. Naringenin is reported to have therapeutic potential against several intestinal disorders. However, the effect of naringenin on GVB disruption has been rarely studied. This study aims to investigate the effect of naringenin on GVB function and the potential mechanism. In the present study, the in vitro GVB disruption of rat intestinal microvascular endothelial cells (RIMVEC) was induced by 50 ng mL of tumor necrosis factor-α (TNF-α). The integrity of the in vitro GVB was determined by Evans blue (EB)-albumin efflux assay and trans-endothelial electrical resistance (TER). Meanwhile, the expression of tight junction proteins and the related NF-κB, MLCK/p-MLC and NLRP3 pathways were determined using enzyme-linked immunosorbent assay (ELISA), real-time quantitative polymerase chain reaction (RT-qPCR), western blot analysis and immunofluorescence. The results show that naringenin (100 μM) inhibits TNF-α-induced interleukin (IL)-6 hypersecretion, alleviates GVB disruption and mitigates the change in the tight junction protein expression pattern. Naringenin inhibits the GVB-disruption-associated activation of the MLCK/p-MLC system and TLR4/NF-κB/NLRP3 pathways. Furthermore, naringenin shows a similar effect to that of NF-κB inhibitor Bay 11-7082 in reducing the TNF-α-induced activation of NLRP3, p-MLC and secondary GVB disruption. The results suggest that naringenin evidently alleviates TNF-α-induced in vitro GVB disruption via the maintenance of a tight junction protein pattern, partly with the inhibition of the NF-κB-mediated MLCK/p-MLC and NLRP3 pathway activation.
微血管内皮细胞能精确调节肠道-血管屏障（GVB）中分子的通透性，GVB 在肠道免疫中起着至关重要的作用。柚皮素被报道具有治疗多种肠道疾病的潜力。然而，柚皮素对 GVB 破坏的影响很少被研究。本研究旨在探讨柚皮素对 GVB 功能的影响及其潜在机制。本研究中，采用 50ng/mL 肿瘤坏死因子-α（TNF-α）诱导大鼠肠道微血管内皮细胞（RIMVEC）体外 GVB 破坏。通过 Evans 蓝（EB）-白蛋白外排试验和跨内皮电阻（TER）测定体外 GVB 的完整性。同时，采用酶联免疫吸附试验（ELISA）、实时定量聚合酶链反应（RT-qPCR）、Western blot 分析和免疫荧光法测定紧密连接蛋白的表达及相关 NF-κB、MLCK/p-MLC 和 NLRP3 通路。结果表明，柚皮素（100μM）抑制 TNF-α诱导的白细胞介素（IL）-6 过度分泌，缓解 GVB 破坏，并减轻紧密连接蛋白表达模式的变化。柚皮素抑制与 GVB 破坏相关的 MLCK/p-MLC 系统和 TLR4/NF-κB/NLRP3 通路的激活。此外，柚皮素在降低 TNF-α诱导的 NLRP3、p-MLC 和继发性 GVB 破坏的激活方面与 NF-κB 抑制剂 Bay 11-7082 具有相似的作用。结果表明，柚皮素通过维持紧密连接蛋白模式明显减轻 TNF-α诱导的体外 GVB 破坏，部分通过抑制 NF-κB 介导的 MLCK/p-MLC 和 NLRP3 通路的激活。
