Soluble ligands as drug targets for treatment of inflammatory bowel disease

Molecular targets associated with ulcerative colitis and the benefits of atractylenolides-based therapy

Ulcerative colitis (UC) is a chronic inflammatory disease of the intestines that can significantly impact quality of life and lead to various complications. Currently, 5-aminosalicylic acid derivatives, corticosteroids, immunosuppressants, and biologics are the major treatment strategies for UC, but their limitations have raised concerns. Atractylenolides (ATs), sesquiterpene metabolites found in Atractylodes macrocephala Koidz., have shown promising effects in treating UC by exerting immune barrier modulation, alleviating oxidative stress, gut microbiota regulation, improving mitochondrial dysfunction and repairing the intestinal barrier. Furthermore, ATs have been shown to possess remarkable anti-fibrosis, anti-thrombus, anti-angiogenesis and anti-cancer. These findings suggest that ATs hold important potential in treating UC and its complications. Therefore, this review systematically summarizes the efficacy and potential mechanisms of ATs in treating UC and its complications, providing the latest insights for further research and clinical applications.

Dietary protocatechuic acid redistributes tight junction proteins by targeting Rho-associated protein kinase to improve intestinal barrier function

Inflammatory bowel disease (IBD) is continuously increasing globally and caused by intestinal barrier dysfunction. Although protocatechuic acid (PCA) has a protective effect on colitis, the molecular mechanisms underlying its contribution to intestinal barrier function remain unknown. Transepithelial electrical resistance (TEER) and FITC-dextran permeability measurements reveled that PCA suppresses lipopolysaccharide (LPS) and tumor necrosis factor (TNF)-α-induced increase in intestinal permeability; zonula occludens (ZO)-1 and claudin-2 redistribution was also suppressed in the epithelial cell membranes of differentiated Caco-2 cells. PCA was found to directly bind Rho-associated coiled-coil containing protein kinase (ROCK), subsequently suppressing myosin light chain (MLC) phosphorylation. Notably, PCA binds ROCK to a similar degree as Y27632, a selective ROCK inhibitor. Orally administering PCA (5 or 25 mg per kg per day) to C57BL/6 mice alleviated the 3% dextran sulfate sodium (DSS)-induced colitis symptoms including reduced colon length, disrupted intestinal barrier structure, and increased proinflammatory cytokines expressions, such as interleukin (IL)-1β, TNF-α, and IL-6. Furthermore, orally administering PCA suppressed DSS-induced ZO-1 and claudin-2/4 redistribution in mice colon membrane fractions. Therefore, PCA may serve as a promising nutraceutical to improve gut health and alleviate IBD by maintaining intestinal barrier function in vitro and in vivo.

Advancing the precision management of inflammatory bowel disease in the era of omics approaches and new technology

There is great heterogeneity among inflammatory bowel disease (IBD) patients in terms of pathogenesis, clinical manifestation, response to treatment, and prognosis, which requires the individualized and precision management of patients. Many studies have focused on prediction biomarkers and models for assessing IBD disease type, activity, severity, and prognosis. During the era of biologics, how to predict the response and side effects of patients to different treatments and how to quickly recognize the loss of response have also become important topics. Multiomics is a promising area for investigating the complex network of IBD pathogenesis. Integrating numerous amounts of data requires the use of artificial intelligence.

Tackling Inflammatory Bowel Diseases: Targeting Proinflammatory Cytokines and Lymphocyte Homing

Inflammatory bowel diseases (IBDs) are characterized by chronic inflammatory disorders that are a result of an abnormal immune response mediated by a cytokine storm and immune cell infiltration. Proinflammatory cytokine therapeutic agents, represented by TNF inhibitors, have developed rapidly over recent years and are promising options for treating IBD. Antagonizing interleukins, interferons, and Janus kinases have demonstrated their respective advantages in clinical trials and are candidates for anti-TNF therapeutic failure. Furthermore, the blockade of lymphocyte homing contributes to the excessive immune response in colitis and ameliorates inflammation and tissue damage. Factors such as integrins, selectins, and chemokines jointly coordinate the accumulation of immune cells in inflammatory regions. This review assembles the major targets and agents currently targeting proinflammatory cytokines and lymphatic trafficking to facilitate subsequent drug development.

Chitosan-based oral colon-specific delivery systems for polyphenols: recent advances and emerging trends

Oral colon-targeted delivery systems (OCDSs) have attracted great attention in the delivery of active compounds targeted to the colon for the treatment of colon and non-colon diseases with the advantages of enhanced efficacy and reduced side effects. Chitosan, the second-most abundant biopolymer next to cellulose, has great biocompatibility, is non-toxic, is sensitive to colonic flora and shows strong adhesion to colonic mucus, making it an ideal biomaterial candidate for the construction of OCDSs. Being rich in functional groups, the chitosan structure is easily modified, both physically and chemically, for the fabrication of delivery systems with diverse geometries, including nanoparticles, microspheres/microparticles, and hydrogels, that are resistant to the harsh environment of the upper gastrointestinal tract (GIT). This review offers a detailed overview of the preparation of chitosan-based delivery systems as the basis for building OCDSs. A variety of natural polyphenols with potent biological activities are used to treat diseases of the colon, or to be metabolized as active ingredients by colonic microorganisms to intervene in remote organ diseases after absorption into the circulation. However, the poor solubility of polyphenols limits their application, and the acidic environment of the upper GIT and various enzymes in the small intestine disrupt their structure and activity. As a result, the development of OCDSs for polyphenols has become an emerging and popular area of current research in the past decade. Thus, the second objective of this review is to systematically summarize the most recent research findings in this area and shed light on the future development of chitosan-based OCDSs for nutritional and biomedical applications.

Effects of Osthole on Inflammatory Gene Expression and Cytokine Secretion in Histamine-Induced Inflammation in the Caco-2 Cell Line

Hyperactivity of the immune system in the gastrointestinal tract leads to the development of chronic, inflammation-associated disorders. Such diseases, including inflammatory bowel disease, are not completely curable, but the specific line of treatment may reduce its symptoms. However, the response to treatment varies among patients, creating a necessity to uncover the pathophysiological basis of immune-mediated diseases and apply novel therapeutic strategies. The present study describes the anti-inflammatory properties of osthole during histamine-induced inflammation in the intestinal Caco-2 cell line. Osthole reduced the secretion of cytokines (CKs) and the expression level of inflammation-associated genes, which were increased after a histamine treatment. We have shown that the secretion of pro-inflammatory CKs (IL-1β, IL-6, IL-8, and TNF-α) during inflammation may be mediated by NFκB, and, after osthole treatment, this signaling pathway was disrupted. Our results suggest a possible role for osthole in the protection against inflammation in the gastrointestinal tract; thus, osthole may be considered as an anti-inflammatory modulator.

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.