Department of Gastroenterology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215000, P.R. China.
Department of Gastroenterology and Hepatology, Minhang Hospital, Fudan University, Shanghai 201100, P.R. China.
Mol Med Rep. 2024 Oct;30(4). doi: 10.3892/mmr.2024.13313. Epub 2024 Sep 2.
Indole‑3‑propionic acid (IPA), a product of metabolism, has been shown to improve intestinal barrier function. In the present study, in vitro experiments using NCM460 human colonic epithelial cells were performed to investigate how IPA alleviates lipopolysaccharide (LPS)‑induced intestinal epithelial cell injury, with the aim of improving intestinal barrier function. In addition, the underlying mechanism was explored. NCM460 cell viability and apoptosis were measured using the Cell Counting Kit‑8 assay and flow cytometry, respectively. The integrity of the intestinal epithelial barrier was evaluated by measuring transepithelial electrical resistance (TEER). The underlying molecular mechanism was explored using western blotting, immunofluorescence staining, a dual luciferase reporter gene assay and quantitative PCR. The results showed that 10 µg/ml LPS induced the most prominent decrease in cell viability after 24 h of treatment. By contrast, IPA effectively inhibited LPS‑induced apoptosis in the intestinal epithelial cells. Additionally, >0.5 mM IPA improved intestinal barrier function by increasing TEER and upregulating the expression of tight junction proteins (zonula occludens‑1, claudin‑1 and occludin). Furthermore, IPA inhibited the release of pro‑inflammatory cytokines (IL‑1β, IL‑6 and TNF‑α) in a dose‑dependent manner and this was achieved via regulation of the Toll‑like receptor 4 (TLR4)/myeloid differentiation factor 88/NF‑κB and TLR4/TRIF/NF‑κB pathways. In conclusion, IPA may alleviate LPS‑induced inflammatory injury in human colonic epithelial cells. Taken together, these results suggest that IPA may be a potential therapeutic approach for the management of diseases characterized by LPS‑induced intestinal epithelial cell injury and intestinal barrier dysfunction.
吲哚丙酸（IPA）是一种代谢产物，已被证明可改善肠道屏障功能。本研究通过体外实验使用 NCM460 人结肠上皮细胞，研究 IPA 如何缓解脂多糖（LPS）诱导的肠道上皮细胞损伤，旨在改善肠道屏障功能。此外，还探讨了其潜在机制。通过 Cell Counting Kit-8 检测和流式细胞术分别检测 NCM460 细胞活力和细胞凋亡。通过测量跨上皮电阻（TEER）评估肠道上皮屏障的完整性。通过 Western blot、免疫荧光染色、双荧光素酶报告基因检测和定量 PCR 探讨潜在的分子机制。结果显示，10 µg/ml LPS 处理 24 h 后可显著降低细胞活力。相比之下，IPA 可有效抑制 LPS 诱导的肠道上皮细胞凋亡。此外，>0.5 mM IPA 通过增加 TEER 和上调紧密连接蛋白（闭合蛋白-1、claudin-1 和闭合蛋白）的表达来改善肠道屏障功能。此外，IPA 呈剂量依赖性抑制促炎细胞因子（IL-1β、IL-6 和 TNF-α）的释放，这是通过调节 Toll 样受体 4（TLR4）/髓样分化因子 88/NF-κB 和 TLR4/TRIF/NF-κB 途径实现的。总之，IPA 可能减轻 LPS 诱导的人结肠上皮细胞炎症损伤。综上所述，这些结果表明 IPA 可能是治疗 LPS 诱导的肠道上皮细胞损伤和肠道屏障功能障碍相关疾病的潜在治疗方法。
