Wheat Germ-Derived Peptide Alleviates Dextran Sulfate Sodium-Induced Colitis in Mice

Pharmacological modulation of mitochondrial function as novel strategies for treating intestinal inflammatory diseases and colorectal cancer

Inflammatory bowel disease (IBD) is a chronic and recurrent intestinal disease, and has become a major global health issue. Individuals with IBD face an elevated risk of developing colorectal cancer (CRC), and recent studies have indicated that mitochondrial dysfunction plays a pivotal role in the pathogenesis of both IBD and CRC. This review covers the pathogenesis of IBD and CRC, focusing on mitochondrial dysfunction, and explores pharmacological targets and strategies for addressing both conditions by modulating mitochondrial function. Additionally, recent advancements in the pharmacological modulation of mitochondrial dysfunction for treating IBD and CRC, encompassing mitochondrial damage, release of mitochondrial DNA (mtDNA), and impairment of mitophagy, are thoroughly summarized. The review also provides a systematic overview of natural compounds (such as flavonoids, alkaloids, and diterpenoids), Chinese medicines, and intestinal microbiota, which can alleviate IBD and attenuate the progression of CRC by modulating mitochondrial function. In the future, it will be imperative to develop more practical methodologies for real-time monitoring and accurate detection of mitochondrial function, which will greatly aid scientists in identifying more effective agents for treating IBD and CRC through modulation of mitochondrial function.

Fucoidan from Apostichopus japonicus enhances intestinal barrier function and promotes intestinal immunity via regulating the gut microbiota and tryptophan metabolism

Apostichopus japonicus is one of the most popular types of sea cucumber among consumers in Southeast Asia. Fucoidan from Apostichopus japonicus (Aj-FUC) has attracted considerable attention because of its immunomodulatory activities. Aj-FUC is indigestible in the human upper gastrointestinal tract but can be utilized by the gut microbiota. Thus, we suspect that Aj-FUC interacts with the gut to enhance immunefunction. This study showed that after a three-week intervention with Aj-FUC (100 mg/kg/d), the gut microbiota in mice developed a new homeostasis. Subsequently, in the condition of intestinal flora homeostasis, the effects of Aj-FUC on intestinal health in normal mice and the prevention of intestinal mucosal damage in cyclophosphamide-induced mice were investigated. Aj-FUC preserved intestinal structural integrity, increased the number of goblet cells, upregulated the expression of ZO-1 and Occludin, stimulated the secretion of sIgA and IgA, and maintained the Th1/Th2 balance. Importantly, beneficial bacteria were enriched, and tryptophan metabolism-related metabolites such as 5-hydroxyindole-3-acetic acid, and indole-3-lactic acid were upregulated following Aj-FUC administration. In summary, a three-week Aj-FUC intervention could result in the formation of a new homeostasis in intestinal flora, while the effect of Aj-FUC on intestinal immunity was related to the regulation of tryptophan metabolism by gut microbiota.

Enhancing colonic health with encapsulated grape seed anthocyanins: Oral capsule for Colon-targeted delivery

Grape seed anthocyanins (GSA) offer health benefits and protect against diseases, including colitis. Its unpleasant smell and instability prevent widespread application. Antisolvent pretreatment GSA was encapsulated in chitosan-phytic acid 3D gel network. SEM and X-ray diffraction results demonstrate that pretreatment reduces GSA particle size and exhibits amorphous structure. FTIR confirmed they were physically encapsulated and not covalently bound. Its subsequent simulations digestion and fermentation showed only 26.69 % upper digestive tract leakage and altered gut microbiota and metabolites profile. In DSS-induced colitis model, it ameliorated the symptoms, including diarrhea, bloody stools, weight loss, and DAI score. Additionally, it regulates colitis mice pro- and anti-inflammatory cytokines, modifies cecum and colon SCFA profile, improves intestinal barrier, and restores colonic cell redox equilibrium. Collectively, GSA ameliorates experimental colitis via inhibiting TRL4/NF-κB and activating Nrf2 signaling pathway. In conclusion, we propose our GSA capsule can effectively deliver an intact parent form of GSA to the colon and has the potential to be a colonic health strategy.

Effect of Food Matrix on Regulation of Intestinal Barrier and Microbiota Homeostasis by Polysaccharides Sulfated Carrageenan

Carrageenan (CGN) has side effects on the intestinal barrier. Damage to the intestinal barrier is associated with exposure to sulfate groups. Food matrix has significant influence on the exposure quantity of sulfate groups and conformation in κ-CGN, but the corresponding side effects are not reported specifically. This study aimed to explore the regulatory effect of κ-CGN dissolved in aqueous (κ-CGN) and in 3% casein (κ-carrageenan-casein, κ-CC) on the intestinal barrier and microbiota homeostasis. Research has shown that both κ-CGN and κ-CC can induce different extents of intestinal barrier damage through disrupting microbiota homeostasis. Importantly, κ-CGN in casein with lower sulfate groups content was found to repair the intestinal barrier injury induced by an equivalent dose of κ-CGN aqueous through increasing the abundance of Oscillibacter and decreasing Weissella. These alleviating effects were reflected in lower levels of tumor necrosis factor (TNF)-α and C-reaction protein (CRP), higher levels of interleukin (IL)-10, raised secretion of mucus and goblet cells, and improved expression of epithelial cell compact proteins zonula occluden (ZO)-1 and mucin protein 2 (MUC2). This study states that κ-CGN in casein has a positive regulatory effect on the intestinal barrier damage compared to in aqueous solution, which can provide guidance for processing and utilization of CGN.

Unveiling the therapeutic potential and mechanism of inulin in DSS-induced colitis mice

Inulin has been reported to alleviate colitis. In this study, colitis patients' feces were used to simulate fermentation to demonstrate changes in the microbiota profile in the presence of inulin. We found inulin can reshape the gut microbiota profile of colitis patients, especially by altering the abundance of Faecalibacterium and Blautia. Interestingly, the subsequent co-culture with inulin demonstrated that inulin promoted the growth of these two strains of bacteria. The dextran sodium sulfate (DSS)-induced mouse model was used to examine the effect of inulin and its combination with two probiotics on colitis. Results showed that all three treatments can alleviate the clinical symptoms, including weight-losing, colon-shortening, and the Disease Activity Index (DAI) score. Further investigations showed that the administrations regulate colitis mice's pro- and anti-inflammatory cytokines, such as TNF-α, IL-1β, IL-6, IL-10, and IL-17. Also, they alter the relative abundance of Faecalibacterium and Blautia, change the short-chain fatty acids (SCFAs) profile in the cecum and colon, and improve the intestinal barrier; specifically, the intervention increased the expressions of Claudin, Occludin, Zonula Occludens (ZO)-1, and Mucin (MUC)-2 in colonic tissues, thus restoring the colonic tissue structure and morphology of colitis mice. Collectively, our results confirm that inulin can alter the colitis patients' characteristic microbial community, and they can ameliorate experimental colitis by inhibiting the TRL4/MyD88/NF-κB signaling pathway-improving the inflammatory response and enhancing the intestinal barrier. In conclusion, we propose that inulin may hold promise as a functional food therapeutic approach for the treatment of colitis.

p-Hydroxy benzaldehyde, a phenolic compound from Nostoc commune, ameliorates DSS-induced colitis against oxidative stress via the Nrf2/HO-1/NQO-1/NF-κB/AP-1 pathway

BACKGROUND

Ulcerative colitis (UC), a chronic idiopathic inflammatory bowel disease (IBD), presents with limited current drug treatment options. Consequently, the search for safe and effective drug for UC prevention and treatment is imperative. Our prior studies have demonstrated that the phenolic compound p-Hydroxybenzaldehyde (HD) from Nostoc commune, effectively mitigates intestinal inflammation. However, the mechanisms underlying HD's anti-inflammatory effects remain unclear.

PURPOSE

This study delved into the pharmacodynamics of HD and its underlying anti-inflammation mechanisms.

METHODS

For in vivo experiments, dextran sodium sulfate (DSS)-induced colitis mouse model was established. In vitro inflammation model was established using lipopolysaccharide (LPS)-induced RAW264.7 and bone marrow-derived macrophages (BMDMs). The protective effect of HD against colitis was determined by monitoring clinical symptoms and histological morphology in mice. The levels of inflammatory factors and oxidative stress markers were subsequently analyzed with enzyme-linked immunosorbent assay (ELISA) and biochemical kits. Furthermore, western blotting (WB), immunofluorescence (IF), luciferase reporter gene, drug affinity reaction target stability (DARTS) assay, molecular docking, and molecular dynamics (MD) simulation were used to determine the potential target and molecular mechanism of HD.

RESULTS

Our findings indicate that HD significantly alleviated the clinical symptoms and histological morphology of colitis in mice, and curtailed the production of pro-inflammatory cytokines, including TNF-α, IL-6, IFN-γ, COX-2, and iNOS. Furthermore, HD stimulated the production of SOD, CAT, and GSH-px, enhanced total antioxidant capacity (T-AOC), and reduced MDA levels. Mechanically, HD augmented the expression of Nrf2, HO-1, and NQO-1, while concurrently downregulating the phosphorylation of p65, IκBα, c-Jun, and c-Fos. ML385 and siNrf2 largely attenuated the protective effect of HD in enteritis mice and RAW 264.7 cells, as well as the promotion of HO-1 expression levels. ZnPP-mediated HO-1 knockdown reversed HD-induced inhibition of colonic inflammation. Luciferase reporter assay and IF assay confirmed the transcriptional activation of Nrf2 by HD. DARTS analysis, molecular docking, and MD results showed high binding strength, interaction efficiency and remarkable stability between Nrf2 and HD.

CONCLUSION

These outcomes extend our previous research results that HD can combat oxidative stress through the Nrf2/HO-1/NQO-1/NF-κB/AP-1 pathways, effectively alleviating colitis, and propose new targets for HD to protect against intestinal barrier damage.

Gypenoside LXXV Alleviates Colitis by Reprograming Macrophage Polarization via the Glucocorticoid Receptor Pathway

An imbalance in the macrophage phenotype is closely related to various inflammatory diseases. Here, we discovered that gypenoside LXXV (GP-75), a type of saponin from Gynostemma pentaphyllum, can reprogram M1-like macrophages into M2-like ones. On a mechanistic level, GP-75 inhibits NF-κB-COX2 signaling by targeting the glucocorticoid receptor (GR). Administration of GP-75, either orally or by intraperitoneal injection, significantly alleviates ulcerative colitis in mice, a pathogenesis associated with macrophage polarization. Clodronate liposomes, which deplete macrophages in mice, as well as GR antagonist RU486, abrogate the anticolitis effect of GP-75, thus confirming the pivotal role of macrophages in GP-75 function. We also showed that GP-75 has no toxicity in mice. Overall, this is the first report that demonstrates the effect of GP-75 on macrophage reprograming and as an agent against colitis. Because G. pentaphyllum is gaining popularity as a functional food, our findings offer new perspectives on the use of gypenosides as potential nutraceuticals for medical purposes.

Structure and regulatory mechanisms of food-derived peptides in inflammatory bowel disease: A review

The number of patients with inflammatory bowel disease (IBD) is increasing worldwide. Since IBD is a chronic disease that seriously affects patients' life quality, preventing and alleviating IBD with natural and less side effect substances has become a research hotspot. Food-derived bioactive peptides have been an attractive research focus due to their high efficiency and low toxicity. This paper comprehensively summarizes food-derived peptides with intestinal health effects, focusing on peptide sequences with IBD-regulatory effects and emphasizing the effects of their structure and physicochemical properties such as peptide length, amino acid composition, and net charge on their function. We also analyzed its regulatory mechanisms, mainly in 5 aspects: modulating the intestinal microbiota, decreasing intestinal epithelial permeability, increasing antioxidant ability, regulating the expression of inflammatory cytokines, and targeting signaling pathways. This review will help establish novel, efficient screening methods for IBD-regulatory peptides and contribute to further research and discovery of them.

Wheat peptide alleviates DSS-induced colitis by activating the Keap1-Nrf2 signaling pathway and maintaining the integrity of the gut barrier

Inflammatory bowel disease (IBD) is difficult to cure, and formulating a dietary plan is an effective means to prevent and treat this disease. Wheat peptide contains a variety of bioactive peptides with anti-inflammatory and antioxidant functions. The results of this study showed that preventive supplementation with wheat peptide (WP) can significantly alleviate the symptoms of dextran sulfate sodium (DSS)-induced colitis in mice. WP can increase body weight, alleviate colon shortening, and reduce disease activity index (DAI) scores. In addition, WP improved intestinal microbial disorders in mice with colitis. Based on LC-MS, a total of 313 peptides were identified in WP, 4 of which were predicted to be bioactive peptides. The regulatory effects of WP and four bioactive peptides on the Keap1-Nrf2 signaling pathway were verified in Caco-2 cells. In conclusion, this study demonstrated that WP alleviates DSS-induced colitis by helping maintain gut barrier integrity and targeting the Keap1-Nrf2 axis; these results provided a rationale for adding WP to dietary strategies to prevent IBD.

Study on the Protective Effect and Mechanism of Umbilicaria esculenta Polysaccharide in DSS-Induced Mice Colitis and Secondary Liver Injury

This study aimed to explore the ameliorative effects and potential mechanisms of Huangshan Umbilicaria esculenta polysaccharide (UEP) in dextran sulfate sodium-induced acute ulcerative colitis (UC) and UC secondary liver injury (SLI). Results showed that UEP could ameliorate both colon and liver pathologic injuries, upregulate mouse intestinal tight junction proteins (TJs) and MUC2 expression, and reduce LPS exposure, thereby attenuating the effects of the gut-liver axis. Importantly, UEP significantly downregulated the secretion levels of TNF-α, IL-1β, and IL-6 through inhibition of the NF-κB pathway and activated the Nrf2 signaling pathway to increase the expression levels of SOD and GSH-Px. In vitro, UEP inhibited the LPS-induced phosphorylation of NF-κB P65 and promoted nuclear translocation of Nrf2 in RAW264.7 cells. These results revealed that UEP ameliorated UC and SLI through NF-κB and Nrf2-mediated inflammation and oxidative stress. The study first investigated the anticolitis effect of UEP, suggesting its potential for the treatment of colitis and colitis-associated liver disease.

Turtle peptide and its derivative peptide ameliorated DSS-induced ulcerative colitis by inhibiting inflammation and modulating the composition of the gut microbiota

Ulcerative colitis (UC) is a recurrent intestinal disease with an increasing incidence worldwide that seriously affects the life of patients. Turtle peptide (TP) is a bioactive peptide extracted from turtles that has anti-inflammatory, antioxidant and anti-aging properties. However, studies investigating the effect of TP on the progression of UC are lacking. The aim of this study was to investigate effects and underlying mechanisms of TP and its derivative peptide GPAGPIGPV (GP-9) in alleviating UC in mice. The results showed that 500 mg/kg TP treatment significantly ameliorated colitis symptoms and oxidative stress in UC mice. TP alleviated intestinal barrier damage in UC mice by promoting mucosal repair and increasing the expression of tight junction proteins (ZO1, occludin and claudin-1). TP also modulated the composition of the gut microbiota by increasing the abundance of the beneficial bacteria Anaerotignum, Prevotellaceae_UCG-001, Alistipes, and Lachno-spiraceae_NK4A136_group and decreasing the abundance of the harmful bacteria Prevotella_9 and Parasutterella. Furthermore, we characterized the peptide composition of TP and found that GP-9 ameliorated the symptoms of dextran sodium sulfate (DSS)-induced colitis in mice by inhibiting the TLR4/NF-κB signaling pathway. In conclusion, TP and its derivative peptides ameliorated DSS-induced ulcerative colitis by inhibiting the expression of inflammatory factors and modulating the composition of the intestinal microbiota; this study provides a theoretical basis for the application of TP and its derivative peptides for their anti-inflammatory activity.

Chensinin-1b Alleviates DSS-Induced Inflammatory Bowel Disease by Inducing Macrophage Switching from the M1 to the M2 Phenotype

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disorder with an increasing prevalence worldwide. Macrophage polarization is involved in the pathogenesis of IBD. Repolarization of macrophage has thus emerged as a novel therapeutic approach for managing IBD. Chensinin-1b, derived from the skin of Rana chensinensis, is a derivative of a native antimicrobial peptide (AMP). It shows anti-inflammatory effects in sepsis models and can potentially modulate macrophage polarization. The objective of this research was to study the role of chensinin-1b in macrophage polarization and dextran sulfate sodium (DSS)-induced colitis. RAW264.7 macrophages were polarized to the M1 phenotype using lipopolysaccharide (LPS) and simultaneously administered chensinin-1b at various concentrations. The ability of chenisnin-1b to reorient macrophage polarization was assessed by ELISA, qRT-PCR, and flow cytometry analysis. The addition of chensinin-1b significantly restrained the expression of M1-associated proinflammatory cytokines and surface markers, including TNF-α, IL-6, NO, and CD86, and exaggerated the expression of M2-associated anti-inflammatory cytokines and surface markers, including IL-10, TGF-β1, Arg-1, Fizz1, Chil3, and CD206. Mechanistically, via Western Blotting, we revealed that chensinin-1b induces macrophage polarization from the M1 to the M2 phenotype by inhibiting the phosphorylation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK). In mouse models of colitis, intraperitoneal administration of chensinin-1b alleviated symptoms induced by DSS, including weight loss, elevated disease activity index (DAI) scores, colon shortening, colonic tissue damage, and splenomegaly. Consistent with our in vitro data, chensinin-1b induced significant decreases in the expression of M1 phenotype biomarkers and increases in the expression of M2 phenotype biomarkers in the mouse colitis model. Furthermore, chensinin-1b treatment repressesed NF-κB phosphorylation in vivo. Overall, our data showed that chensinin-1b attenuates IBD by repolarizing macrophages from the M1 to the M2 phenotype, suggesting its potential as a therapeutic candidate for IBD.

Oat Peptides Alleviate Dextran Sulfate Sodium Salt-Induced Colitis by Maintaining the Intestinal Barrier and Modulating the Keap1-Nrf2 Axis

The prevalence of inflammatory bowel disease (IBD) is progressively rising each year, emphasizing the significance of implementing rational dietary interventions for disease prevention. Oats, being a staple agricultural product, are abundant in protein content. This study aimed to investigate the protective effects and underlying mechanisms of oat peptides (OPs) in a mouse model of acute colitis induced by dextran sulfate sodium salt (DSS) and a Caco-2 cell model. The findings demonstrated that intervention with OPs effectively mitigated the symptoms associated with DSS-induced colitis. The physicochemical characterization analysis demonstrated that the molecular weight of the OPs was predominantly below 5 kDa, with a predominant composition of 266 peptides. This study provides further evidence of the regulatory impact of OPs on the Keap1-Nrf2 signaling axis and elucidates the potential role of WGVGVRAERDA as the primary bioactive peptide responsible for the functional effects of OPs. Ultimately, the results of this investigation demonstrate that OPs effectively mitigate DSS-induced colitis by preserving the integrity of the intestinal barrier and modulating the Keap1-Nrf2 axis. Consequently, these findings establish a theoretical foundation for the utilization of OPs as dietary supplements to prevent the onset of IBD.