Lan-Ru Huang

(1) Background: This study investigates the effects of Ursodeoxycholic acid (UDCA) on NF-κB signaling, farnesoid X receptor (FXR) singling, and microRNA-21 in HepG2 cells. (2) Methods: HepG2 cells were treated with lipopolysaccharide (LPS) to simulate hepatic inflammation. The investigation focused on the expression of NF-κB activation, which was analyzed using Western blot, confocal microscopy, and Electrophoretic Mobility-shift Assays (EMSA). Additionally, NF-κB and farnesoid X receptor (FXR) singling expressions of micro-RNA-21, COX-2, TNF-α, IL-6, cyp7A1, and shp were assessed by RT-PCR. (3) Results: UDCA effectively downregulated LPS-induced expressions of NF-κB/65, p65 phosphorylation, and also downregulated FXR activity by Western blot. Confocal microscopy and EMSA results confirmed UDCA’s role in modulating NF-κB signaling. UDCA reduced the expressions of LPS-induced COX-2, TNF-α, and IL-6, which were related to NF-κB signaling. UDCA downregulated LPS-induced cyp7A1 gene expression and upregulated shp gene expression, demonstrating selective gene regulation via FXR. UDCA also significantly decreased micro-RNA 21 levels. (4) Conclusions: This study demonstrates UDCA’s potent anti-inflammatory effects on NF-κB and FXR signaling pathways, and thus its potential to modulate hepatic inflammation and carcinogenesis through interactions with NF-κB and FXR. The decrease in micro-RNA 21 expression further underscores its therapeutic potential.

Infection of gastric epithelial cells by Helicobacter pylori stimulates the activation of nuclear factor-κB (NF-κB) and the upregulation of interleukin-8 (IL-8) expression. Activation of NF-κB can occur through classical (p50/p65) and alternative (p52/RelB) pathways. The role of the bacterial cag pathogenicity island (PAI) in these events is controversial. This study aimed to evaluate the hypothesis that the CagA protein is required for H. pylori-induced activation of NF-κB and upregulation of IL-8 expression, and for clarithromycin (CAM) to exert its molecular effects. Cultured KATO-III human gastric cancer cells were treated with extracts of H. pylori strains ATCC43504 (cag PAI⁺) and ATCC51932 (cag PAI⁻) for 24 h. NF-κB and phospho-IκB protein expression was then evaluated using western blotting. IL-8 mRNA expression was evaluated using the reverse transcription polymerase chain reaction. Following the separation of the proteins using two-dimensional gel electrophoresis, proteomes of the two bacterial extracts were compared using nanoflow liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) analysis. Although the protein profiles of the two extracts differed, both extracts induced IκBα phosphorylation, upregulation of IL-8 expression, and NF-κB activation through classical and alternative pathways. In cells treated with either of the bacterial extracts, CAM inhibited H. pylori-induced activation of NF-κB and upregulation of IL-8 expression. These results suggested that CagA is not required for H. pylori-induced activation of NF-κB and upregulation of IL-8 expression in gastric epithelial cells. H. pylori-induced NF-κB signaling can occur through classical and alternative activation pathways, and that CAM inhibits these two pathways.

Reactive oxygen species (ROS) have been implicated in inflammatory and cancerous illness, including that of the gastrointestinal tract. The oxidative damage incurred during human gastric ulcer or cancer mucosa may be related to acumination of ROS. In this study, we aimed to demonstrate oxidative stress of gastric ulcer and cancer mucosa compared to gastric antral mucosa. Thirty-four patients with gastric ulcer and gastric cancer were enrolled in this study. Gastric mucosa specimens, taken from upper GI endoscopic biopsy, from the lesion (ulcer or cancer) and antrum were sent for the activity of O2- or H2O2 determined by chemiluminescence assay. Protein concentrations in the tissue homogenates were determined by Bio-Red protein assay. The production of O2- or H2O2 per unit of protein was calculated by dividing the tissue CL level by the protein content of a tissue. The oxidative stress metabolites O2- and H2O2 of mucosa were evaluated by chemiluminescence assay in gastric lesions (27 ulcers and 7 cancers) and gastric antrum. Gastric lesion showed significantly increased O2- than antral mucosa (18.77 +/- 45.18 (counts/sec x microg), 95% CI 3.01, 34.53 vs. 3.58 +/- 6.89 (counts/sec x microg), 95% CI 1.18, 5.98, p < 0.05). There was also significantly greater expression of H2O2 in gastric lesion than gastric antral mucosa (76.06 +/- 148.36 (counts/sec x microg), 95% CI 24.30, 127.83 vs. 912.41 +/- 20.22 (counts/sec x microg), 95% CI 5.35, 19.46, p = 0.008). Differences of mucosal O2- and H2O2 between gastric ulcer and cancer were not significant. There was significant correlation of O2- and H2O2 generation in gastric lesion mucosa. Oxidative stress is now thought to make a significant contribution to inflammatory disease and malignancy. The reason that overproduction of free radicals is a feature of such a broad spectrum of diseases derived from the fact that oxidative metabolism is a necessary part of every cell's metabolism. In this study, we demonstrated increased ROS production in gastric ulceration and cancer compared with gastric antral mucosa.