Role of the IL-23-T-bet/GATA3 Axis for the Pathogenesis of Ulcerative Colitis

TH17 cell: a double-edged sword in the development of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic nonspecific inflammatory disease of the gastrointestinal tract, and its pathogenesis has not been fully understood. Extensive dysregulation of the intestinal mucosal immune system is critical in the development and progression of IBD. T helper (Th) 17 cells have the characteristics of plasticity. They can transdifferentiate into subpopulations with different functions in response to different factors in the surrounding environment, thus taking on different roles in regulating the intestinal immune responses. In this review, we will focus on the plasticity of Th17 cells as well as the function of Th17 cells and their related cytokines in IBD. We will summarize their pathogenic and protective roles in IBD under different conditions, respectively, hoping to further deepen the understanding of the pathological mechanisms underlying IBD and provide insights for future treatment.

The therapeutic mechanism of Chebulae Fructus in the treatment of immunosuppression in Chinese yellow quail on the basis of network pharmacology

Introduction

Chebulae Fructus (Terminalia chebula Retz.) is a well-known traditional Chinese medicine (TCM), one of the family Combretaceae, whose immature fruit is called Fructus Chebulae Immaturus or Zangqingguo. This present study aimed at detecting the target and therapeutic mechanism of Chebulae Fructus against immunosuppression through network analysis and experimental validation.

Methods

Effective components and potential targets of Chebulae Fructus were Search and filtered through the Chinese herbal medicine pharmacology data and analysis platform. A variety of known disease target databases were employed to screen the therapeutic target proteins against immunosuppression and thus constructing a protein-protein interaction network. Hub genes and key pathways in this study were identified by continuous project enrichment analysis. Further, the core targets and therapeutic mechanism of Chebulae Fructus against immunosuppression in Chinese yellow quail through animal experiment.

Results

Seventy-five identifiable major candidate targets of Chebulae Fructus were found and thus constructing a drug-compound-target-disease network. Targets derived from gene enrichment analysis play pivotal roles in lipid and atherosclerosis, fluid shear stress and atherosclerosis, and the hepatitis B pathway. Height of plicate and areas of lymphoid follicle were both increased and the expression of GATA-3 and T-bet was upregulated in Chinese yellow quail fed with Chebulae Fructus in animal experiment.

Conclusion

Chebulae Fructus may be a helpful Chinese medicine with immunosuppressive effect and prospective applications in future. Further research is also needed to understand the mechanisms of immunosuppression and the mechanism of action of immunomodulators.

A novel inflammatory marker for extensive ulcerative colitis; Endocan

BACKGROUND & AIMS

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by mucosal inflammation. Endocan, a proteoglycan secreted by endothelial cells in response to inflammatory cytokines, has been reported to be overexpressed in inflammatory conditions. In this study, we aimed to evaluate the utility of endocan level in determining the extent and severity of disease in patients with ulcerative colitis and to determine whether it can be a candidate marker for noninvasive evaluation and monitoring since there is not enough data in the literature.

MATERIALS AND METHODS

Sixty-five people were included in the study, including thirty-five with ulcerative colitis and thirty in the control group. Patients with first diagnosed ulcerative colitis clinically, endoscopically, and histopathologically, without any treatment, and with normal liver and kidney tests were included in the study. Endoscopic scoring of all patients was performed according to the Mayo endoscopic scoring (MES) system. Blood samples for CRP (C-reactive protein) and endocan were taken from the patients simultaneously.

RESULTS

There was a significant statistical difference between all patients with ulcerative colitis and the control group in both endocan level and CRP level (p < 0.001). There was a statistically significant difference between endocan levels and CRP levels between the left-distal group and pancolitis (diffuse colitis) patients, but there was no statistical difference between age and MES.

CONCLUSION

Serum endocan level can be useful in determining the extent of ulcerative colitis and planning treatment.

Effect of curcumin on regulatory B cells in chronic colitis mice involving TLR/MyD88 signaling pathway

Curcumin (Cur) is a natural active phenolic compound extracted from the root of Curcuma Longa L. It has anti-inflammatory, anti-tumor and other pharmacological activities, and is commonly used to treat ulcerative colitis (UC). However, it is not clear whether curcumin regulates the function and differentiation of Breg cells to treat UC. In this study, mice with chronic colitis were induced by dextran sulfate sodium (DSS), and treated with curcumin for 12 days. Curcumin effectively improved the body weight, colonic weight, colonic length, decreased colonic weight index and pathological injury score under colonoscopy in mice with chronic colitis, and significantly inhibited the production of IL-1β, IL-6, IL-33, CCL-2, IFN-γ, TNF-α, and promoted the secretion of IL-4, IL-10, IL-13 and IgA. Importantly, curcumin markedly upregulated CD3^- CD19⁺ CD1d⁺ , CD3^- CD19⁺ CD25⁺ , CD3^- CD19⁺ Foxp3⁺ Breg cells level and significantly down-regulated CD3^- CD19⁺ PD-L1⁺ , CD3^- CD19⁺ tim-1⁺ , CD3^- CD19⁺ CD27⁺ Breg cells level. In addition, our results also showed that curcumin observably inhibited TLR2, TLR4, TLR5, MyD88, IRAK4, p-IRAK4, NF-κB P65, IRAK1, TRAF6, TAB1, TAB2, TAK1, MKK3, MKK6, p38MAPK, p-p38MAPK and CREB expression in TLR/MyD88 signaling pathway. These results suggest that curcumin can regulate the differentiation and function of Breg cell to alleviate DSS-induced colitis, which may be realized by inhibiting TLR/MyD88 pathway.

Interplay between Serotonin, Immune Response, and Intestinal Dysbiosis in Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD) is a chronic gastrointestinal disorder characterized by periods of activity and remission. IBD includes Crohn's disease (CD) and ulcerative colitis (UC), and even though IBD has not been considered as a heritable disease, there are genetic variants associated with increased risk for the disease. 5-Hydroxytriptamine (5-HT), or serotonin, exerts a wide range of gastrointestinal effects under both normal and pathological conditions. Furthermore, Serotonin Transporter (SERT) coded by Solute Carrier Family 6 Member 4 (SLC6A4) gene (located in the 17q11.1-q12 chromosome), possesses genetic variants, such as Serotonin Transporter Gene Variable Number Tandem Repeat in Intron 2 (STin2-VNTR) and Serotonin-Transporter-linked promoter region (5-HTTLPR), which have an influence over the functionality of SERT in the re-uptake and bioavailability of serotonin. The intestinal microbiota is a crucial actor in normal human gut physiology, exerting effects on serotonin, SERT function, and inflammatory processes. As a consequence of abnormal serotonin signaling and SERT function under these inflammatory processes, the use of selective serotonin re-uptake inhibitors (SSRIs) has been seen to improve disease activity and extraintestinal manifestations, such as depression and anxiety. The aim of this study is to integrate scientific data linking the intestinal microbiota as a regulator of gut serotonin signaling and re-uptake, as well as its role in the pathogenesis of IBD. We performed a narrative review, including a literature search in the PubMed database of both review and original articles (no date restriction), as well as information about the SLC6A4 gene and its genetic variants obtained from the Ensembl website. Scientific evidence from in vitro, in vivo, and clinical trials regarding the use of selective serotonin reuptake inhibitors as an adjuvant therapy in patients with IBD is also discussed. A total of 194 articles were used between reviews, in vivo, in vitro studies, and clinical trials.

The influence of cytokines on the complex pathology of ulcerative colitis

Ulcerative colitis (UC) specifically affects the colon and rectum through multifactorial mechanisms associated with genetic alterations, environmental factors, microbiota, and mucosal immune dysregulation. In patients with corticosteroid-refractory UC, current therapies primarily employ antibodies against tumor necrosis factor-α, α4β7 integrin, and interleukin (IL)-12/23 p40; and a small-molecule Janus kinase inhibitor. Despite these revolutionary molecular targeting therapies introduced during the last two decades, 30%-55% of patients fail to respond such molecular targeting agents in the induction phase, requiring changes in treatment. Here we review basic and clinical research aimed to address this problem, focusing on the pathogenic effects of cytokines produced by innate and adaptive immune cells. For example, IL-1β, IL-6, tumor necrosis factor-α, T helper (Th) 1-, Th2-, and Th17-associated cytokines are expressed at relatively higher levels in the intestinal tissues of patients with UC. However, their expression levels depend on disease stage and patient characteristics. The complex pathology of UC may induce differences in responses to therapy. The findings of such studies strongly support the argument that future targeted therapies must focus on differences in cytokine levels associated with the stages of UC as well as on the distinct cytokine expression profiles of individual patients.