Caveolin-1 Alleviates Crohn’s Disease–induced Intestinal Fibrosis by Inhibiting Fibroblasts Autophagy Through Modulating Sequestosome 1

Background Intestinal fibrosis is a common complication of Crohn’s disease (CD) and is characterized by the excessive accumulation of extracellular matrix produced by activated myofibroblasts. Caveolin-1 (CAV1) inhibits fibrosis. However, limited data show that CAV1 affects intestinal fibrosis. Methods Human CD tissue samples were gained from patients with CD who underwent surgical resection of the intestine and were defined as stenotic or nonstenotic areas. A dextran sodium sulfate–induced mouse model of intestinal fibrosis was established. For in vitro experiments, we purchased CCD-18Co intestinal fibrosis cells and isolated and cultured human primary colonic fibroblasts. These fibroblasts were activated by transforming growth factor β administration for 48 hours. In the functional experiments, a specific small interfering RNA or overexpression plasmid was transfected into fibroblasts. The messenger RNA levels of fibrosis markers, such as α-smooth muscle actin, fibronectin, connective tissue growth factor, and collagen I1α, were determined using quantitative polymerase chain reaction. Western blot analysis was applied to detect the expression of CAV1, SQSTM1/p62 (sequestosome 1), and other fibrosis markers. Results In human CD samples and the dextran sodium sulfate–induced mouse model of intestinal fibrosis, we observed a downregulation of CAV1 in fibrosis-activated areas. Mechanistically, CAV1 knockdown in both human primary colonic fibroblasts and CCD-18Co cells promoted fibroblast activation, while CAV1 overexpression inhibited fibroblast activation in vitro. We found that SQSTM1/p62 positively correlated with CAV1 expression levels in patients with CD and that it was indirectly modulated by CAV1 expression. Rescue experiments showed that CAV1 decreased primary human intestinal fibroblast activation by inhibiting fibroblast autophagy through the modulation of SQSTM1/p62. Conclusions Our data demonstrate that CAV1 deficiency induces fibroblast activation by indirectly regulating SQSTM1/p62 to promote fibroblast autophagy. CAV1 or SQSTM1/p62 may be potential therapeutic targets for intestinal fibrosis.

Saccharina japonica Ethanol Extract Ameliorates Depression/Anxiety-Like Behavior by Inhibiting Inflammation, Oxidative Stress, and Apoptosis in Dextran Sodium Sulfate Induced Ulcerative Colitis Mice

Saccharina japonica is a common marine vegetable in East Asian markets and has a variety of health benefits. This study was focused on the anti-depressant/anxiety effects of Saccharina japonica ethanol extract (SJE) on dextran sodium sulfate (DSS)-induced mice and its potential mechanism in their brain. Male C57BL/6 mice were treated with mesalazine and various doses of SJE (1, 2, and 4 g/kg body weight) for 2 weeks, followed by DSS treatment at the second week. The DSS-induced mice showed depression/anxiety-like behavior, which included shorter path length in the open field test and longer immobility time in the tail suspension test. L-SJE alleviated the depression-like behaviors. In the DSS-induced mice, reduced synaptic plasticity activated microglia, increased proinflammatory cytokines, decreased anti-inflammatory cytokine, and increased expression levels of Toll-like receptors-4, nuclear factor kappa-B, NOD-like receptors 3, apoptosis-associated speck-like protein, and Caspase-1 were observed, most of which were alleviated by SJE treatment. Furthermore, all the SJE groups could significantly enhance superoxide dismutase activity, while the L-SJE treatment decreased the contents of malondialdehyde, and the H-SJE treatment inhibited apoptosis. All these results showed that the SJE might serve as a nutritional agent for protecting the brain in ulcerative colitis mice.

The Effects of Sishen Wan on T Cell Responses in Mice Models of Ulcerative Colitis Induced by Dextran Sodium Sulfate

Currently, it is unclear whether Sishen Wan (SSW) could modulate the balance of Th1 cells, Th17 cells, and Tregs and we evaluated the effects of SSW on T cell responses in mice models of ulcerative colitis (UC). The mice models of acute UC (4% dextran sodium sulfate (DSS), 8 days) and chronic UC (3% DSS, 16 days) with SSW were assayed. Colon tissues were collected for immunohistochemical analysis, enzyme linked immunosorbent assay (ELISA), and flow cytometry (FCM). The expressions of cytokines associated with Tregs, transcription factors of Th17 cells, the frequencies of Th1 cells, Th17 cells, and Tregs, and the functional plasticity of Th17 cells were detected. The frequency of IFN-γ+ T cells was not changed significantly with SSW treatment in acute DSS. In chronic models, the frequency of IFN-γ+ T cells was downregulated with SSW. Meanwhile, the levels of RORγt and the frequency of IL-17A+ Th17 cells showed no significant differences after SSW treatment. Despite no significant effect on the transdifferentiation of Th17 cells in chronic UC models, SSW transdifferentiated Th17 cells into IL-10+ Th17 cells and downregulated IFN-γ+ Th17 cells/IL-10+ Th17 cells in acute DSS. Moreover, there were no significant changes of cytokines secreted by Tregs in acute DSS after SSW treatment, but SSW facilitated the expressions of IL-10 and IL-35, as well as development of IL-10+ Tregs in chronic DSS. SSW showed depressive effects on the immunoreaction of Th17 cells and might promote the conversion of Th17 cells into IL-10+ Th17 cells in acute UC, while it inhibited the excessive reaction of Th1 cells, facilitated the development of Tregs, and enhanced the anti-inflammatory effects in chronic UC.

Changes in Gut Bacterial Translation Occur before Symptom Onset and Dysbiosis in Dextran Sodium Sulfate-Induced Murine Colitis

Most studies on the gut microbiome focus on the composition of this community and how it changes during disease. However, how the community transitions from a healthy state to one associated with disease is currently unknown.