College of Pharmacy and Institute of Pharmaceutical Sciences, CHA University, Seongnam 13488, Republic of Korea.
College of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea.
Nutrients. 2022 Dec 25;15(1):99. doi: 10.3390/nu15010099.
Fibrosis has various biological processes and affects almost every organ, especially in patients with inflammatory bowel disease, including Crohn's disease, who experience discomfort caused by intestinal fibrosis, which is a problem that needs to be resolved. TGF-β signaling is known to act as a key regulator of intestinal fibrosis, and its modulation could be an excellent candidate for fibrosis therapy. Xanthohumol (XN) has various effects, including anti-inflammation and anti-cancer; however, the detailed mechanism of TGF-β signaling has not yet been studied. The purpose of this study was to investigate the mechanism underlying the anti-fibrotic effect of XN on TGF-β1-induced intestinal fibrosis using primary human intestinal fibroblasts (HIFs). In this study, to check the anti-fibrotic effects of XN on intestinal fibrosis, we assessed the expression of fibrosis-related genes in TGF-β1-stimulated HIFs by qPCR, immunoblotting, and immunofluorescence staining. As a result, XN showed the ability to reduce the expression of fibrosis-associated genes increased by TGF-β1 treatment in HIFs and restored the cell shape altered by TGF-β1. In particular, XN repressed both NF-κB- and Smad-binding regions in the α-SMA promoter, which is important in fibrosis. In addition, XN inhibited NF-κB signaling, including phosphorylated-IkBα and cyclooxygenase-2 expression, and TNF-α-stimulated transcriptional activity of NF-κB. XN attenuated TGF-β1-induced phosphorylation of Smad2 and Smad3, and the transcriptional activity of CAGA. Particularly, XN interfered with the binding of TGF-Receptor I (TβRI) and Smad3 by binding to the kinase domain of the L45 loop of TβRI, thereby confirming that the fibrosis mechanism did not proceed further. In conclusion, XN has an inhibitory effect on TGF-β1-induced intestinal fibrosis in HIFs, significantly affecting TGF-β/Smad signaling.
纤维化有多种生物学过程，几乎影响所有器官，特别是在炎症性肠病患者中，包括克罗恩病患者，他们会因肠道纤维化而感到不适，这是一个需要解决的问题。TGF-β信号被认为是肠道纤维化的关键调节剂，其调节可能是纤维化治疗的一个很好的候选物。黄腐酚（XN）具有多种作用，包括抗炎和抗癌作用；然而，TGF-β信号的详细机制尚未研究。本研究旨在使用原代人肠成纤维细胞（HIF）研究 XN 对 TGF-β1 诱导的肠道纤维化的抗纤维化作用的机制。在这项研究中，为了检查 XN 对肠道纤维化的抗纤维化作用，我们通过 qPCR、免疫印迹和免疫荧光染色评估了 TGF-β1 刺激的 HIF 中纤维化相关基因的表达。结果表明，XN 能够减少 TGF-β1 处理增加的纤维化相关基因在 HIF 中的表达，并恢复 TGF-β1 改变的细胞形状。特别是，XN 抑制了α-SMA 启动子中 NF-κB 和 Smad 结合区域的表达，这在纤维化中很重要。此外，XN 抑制了 NF-κB 信号转导，包括磷酸化-IkBα 和环氧化酶-2 的表达，以及 TNF-α 刺激的 NF-κB 转录活性。XN 减弱了 TGF-β1 诱导的 Smad2 和 Smad3 的磷酸化，以及 CAGA 的转录活性。特别是，XN 通过与 TβRI 的 L45 环的激酶结构域结合，干扰了 TGF 受体 I（TβRI）和 Smad3 的结合，从而证实纤维化机制没有进一步进行。总之，XN 对 HIF 中 TGF-β1 诱导的肠道纤维化具有抑制作用，显著影响 TGF-β/Smad 信号转导。
