Diosmin alleviates ulcerative colitis in mice by increasing Akkermansia muciniphila abundance, improving intestinal barrier function, and modulating the NF-κB and Nrf2 pathways

Diosmin alleviates colitis by inhibiting PANoptosis of intestinal epithelial cells and regulating gut microbiota and metabolites

BACKGROUND

Inflammatory bowel disease (IBD), particularly ulcerative colitis (UC), is a chronic inflammatory disorder characterized by an unclear etiology, often linked to gut microbiota dysbiosis and immune dysregulation. Existing UC therapies are constrained by suboptimal efficacy and adverse effects, underscoring the necessity for novel therapeutic strategies. Diosmin (DIO), a naturally occurring flavonoid, has demonstrated anti-inflammatory and antioxidant potential, yet its precise mechanisms and therapeutic role in colitis remain poorly understood.

PURPOSE

This study aimed to investigate the therapeutic efficacy and mechanistic underpinnings of DIO in dextran sulfate sodium (DSS)-induced colitis, with a focus on its effects on intestinal epithelial cell PANoptosis, gut microbiota composition, fecal metabolites, and an in vitro inflammatory model using human colonic epithelial cells.

STUDY DESIGN

A controlled experimental design was employed, utilizing a DSS-induced murine colitis model and an LPS-induced inflammatory model in human colonic epithelial cells (NCM460). Mice were allocated into four groups: normal control, DSS-induced colitis, low-dose DIO (DIO-L, 100 mg/kg), and high-dose DIO (DIO-H, 200 mg/kg). In vitro experiments involved treating NCM460 cells with varying DIO concentrations post-LPS stimulation to assess its impact on inflammation and epithelial barrier integrity.

METHODS

Mice were administered DIO orally at 100 mg/kg or 200 mg/kg daily. Therapeutic outcomes were evaluated through body weight monitoring, Disease Activity Index (DAI) scoring, and histopathological examination. Gut microbiota composition was analyzed via 16S rRNA sequencing, while untargeted metabolomics was employed to profile fecal metabolites. Data integration was performed using O2PLS and WGCNA to identify microbiota-metabolite correlations. In vitro, immunofluorescence staining and Western blotting were utilized to evaluate the expression of tight junction proteins (ZO-1, E-cadherin, and Occludin).

RESULTS

DIO administration significantly ameliorated colitis symptoms in mice, as evidenced by attenuated weight loss, reduced DAI scores, and preserved colon length. Histopathological analysis confirmed diminished inflammation and tissue damage in DIO-treated groups. Mechanistically, DIO suppressed the expression of PANoptosis-associated genes and proteins, including ZBP1 and Caspase-1, while maintaining epithelial barrier integrity in vitro. Furthermore, DIO modulated gut microbiota composition, promoting beneficial taxa such as Ruminococcus and reducing pathogenic Proteobacteria. Metabolomic profiling revealed alterations in key metabolic pathways, including flavonoid and steroid hormone biosynthesis, which correlated with microbiota changes.

CONCLUSION

DIO effectively mitigates DSS-induced colitis by inhibiting intestinal epithelial cell PANoptosis, preserving barrier function, and modulating gut microbiota and metabolite profiles. These findings highlight DIO's potential as a therapeutic agent for IBD and warrant further exploration of its clinical applications.

Bacillus clausii spores maintain gut homeostasis in murine ulcerative colitis via modulating microbiota, apoptosis, and the TXNIP/NLRP3 inflammasome cascade

Ulcerative colitis (UC), a persistent immune-mediated disorder lacking effective treatment, is distinguished by gut microbiota dysbiosis, abnormal activation of the NLRP3 inflammasome pathway, and apoptosis. Despite growing attention to these factors, understanding their significance in UC pathogenesis remains a challenge. The present study explores the potential therapeutic impact of Bacillus clausii (Bc) spores in a murine UC model induced by drinking 4 % (w/v) dextran sulfate sodium (DSS) in C57BL/6 mice. Subsequently, the DSS-induced mice were orally administered either Bc at varying concentrations (105 and 1010 Colony forming unit, CFU) or sulfasalazine (SSZ) at a dosage of 200 mg/kg for 7 days. The disease-specific activity index (DAI) was calculated daily utilizing parameters such as body weight, diarrhea, and bloody stool. Changes in fecal Firmicutes and Bacteroidetes abundance, colonic TXNIP and NLRP3 contents, as well as colonic caspase-1, IL-1β, Bax, and Bcl-2 expression, were investigated. Additionally, markers related to oxidative stress and inflammation, histopathological changes and caspase-3 immunohistochemistry testing were conducted. DSS-treated mice had significantly higher DAI scores compared to controls, indicating severe colitis. However, SSZ treatment or Bc (105 CFU) dramatically lowered DAI scores, with the highest Bc dosage (1010 CFU) producing the greatest improvement. Furthermore, Bc (1010 CFU) substantially (p < 0.05) boosted fecal Firmicutes while decreased Bacteroidetes, indicating reversal of gut dysbiosis. Bc effectively reduced colonic oxidative stress and inflammation by replenishing GSH and catalase and modulating the NF-κB, Nrf2/HO-1, and TXNIP/NLRP3 pathways. Additionally, Bc (1010 CFU) exhibited histologically almost normal mucosa, with maintained architecture and reduced apoptosis, as seen by normalization of Bcl2 and Bax with decreased caspase-3. Collectively, these findings point to the potential usefulness of Bc spores in preventing and treating DSS-induced colitis, positioning them as a promising candidate for UC management.

Micronized Purified Flavonoid Fraction (Diosmin/Hesperidin) Ameliorates Cardiac Structural and Functional Integrity in Cisplatin-treated Male Wistar Rats by Modulating NLRP3/Caspase-1/-3 Signaling

Cisplatin is an effective chemotherapeutic agent in managing several cancers. Yet, its usage is restricted by its toxicity to non-target organs, such as cardiotoxicity that is mediated by nucleotide-binding Oligomerisation Domain (NOD)-Like Receptors family pyrin domain containing 3 (NLRP3)-driven inflammation, oxidative stress, and apoptosis. Conversely, micronized purified flavonoid fractions (MPFF) attenuate oxido-inflammation by downregulating NLRP3 inflammasome. However, there is a dearth of information on the effect of MPFF on cisplatin-induced cardiac injury. This study examined the possible protective effect of MPFF in cisplatin-induced cardiac injury. Also, the role of NLRP3 inflammasome and caspase-1/-3 signaling was evaluated. Thirty-two adult male Wistar rats were randomly allotted to four equal groups (n = 8 rats per group). The control received 0.5 mL of distilled water orally daily, the MPFF-treated rats received 100 mg/kg/day of MPFF orally for 14 days, the cisplatin-treated rats had 7 mg/kg of cisplatin via an intraperitoneal route on day 8, and the cisplatin+MPFF -treated rats received cisplatin and MPFF as those in the cisplatin- and MPFF-treated groups. Cisplatin therapy significantly increased cardiac injury markers and plasma glucose. Cisplatin also induced dyslipidemia and insulin resistance. Moreover, cisplatin altered cardiac histology evidenced by vascular congestion, and increased myofibril thickness and interstitial space. These observations were accompanied by cisplatin-induced cardiac oxidative stress (increased malondialdehyde and a decline in reduced glutathione, superoxide dismutase, and catalase), inflammation (increased tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6), apoptosis (increased caspase 1 and caspase 3) and a marked increase in NLPR3 inflammasome. These derangements were blunted by MPFF co-therapy. In conclusion, this study for the first time demonstrated that MPFF attenuated cisplatin-induced cardiac structural and functional damage by suppressing oxidative stress and inflammation via the downregulation of NLPR3 /caspase-1/-3 signaling.

Bifidobacterium animalis Supplementation Improves Intestinal Barrier Function and Alleviates Antibiotic-Associated Diarrhea in Mice

Probiotics have gained increasing recognition for their potential to mitigate antibiotic-associated diarrhea (AAD). However, the precise mechanisms underlying their effects remain unclear. This study developed a mouse model of AAD using ceftriaxone to investigate the alleviating effects and mechanisms of Bifidobacterium animalis A6 (A6). The findings indicated that A6 supplementation effectively attenuated ceftriaxone-associated diarrhea in mice. The morphological damage to the villi and crypts was partially restored and more neatly reorganized following the A6 intervention. Additionally, intestinal morphology observations revealed a significant increase in the thickness of the mucus layer in the A6-treated group. Further examination of key regulatory genes associated with mucus secretion demonstrated that the A6 intervention effectively upregulated the expression of mucin1, thereby reinforcing the mucus layer. Concurrently, the A6 intervention upregulated the expression of the AQP4 and SLC26A3 genes in the intestine, which is responsible for restoring water absorption capacity in AAD mice. Additionally, the A6 treatment reduced ceftriaxone-induced harm to the intestinal microbiota of the mice, boosting beneficial bacteria like Bacteroidales, Akkermansia, Bifidobacterium, and Lactobacillus. Overall, this study offers valuable insights into the potential therapeutic role of A6 in restoring intestinal homeostasis and alleviating symptoms associated with AAD.

Production of secondary metabolites in callus cultures of Scutellaria baicalensis L. and assessment of their anti-inflammatory and antioxidant efficacy in ulcerative colitis rats

Baikal skullcap or Chinese (Scutellaria baicalensis L.) is an interesting plant with promising medicinal properties; however, traditional cultivation methods are time-consuming, and yield variations can be significant; callus culture is considered one of the solutions to overcome these limitations because the callus culture provides an effective, alternative for the consistent production of secondary metabolites. For callus production of S. baicalensis L., the in vitro germinating seedlings were cultured on MS medium containing 1.0 mg/L 6-benzyladenine (BAP) and 1.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D). Three culture lines were established, and the best growth index represented in fresh and dry weight was obtained from line No. 1. S. baicalensis L. callus extract was performed on the best callus line in the stationary phase for in vitro assays. The chemical analysis, antioxidant tests, proline, flavonoids, phenolics, and macronutrient content were assessed. Therefore, this paper aims to evaluate the effectiveness of secondary metabolites in S. baicalensis L. callus and to study its biological effect on recurrent ulcerative colitis (UC). Conventional treatment of UC has focused on suppressing immunological responses instead of addressing which are (UC) underlying causes. Recurrent UC is caused by oxidative stress and inflammation that lead to chronic inflammation of the inner lining of the colon and rectum. According to the findings, secondary metabolites in S. baicalensis L. callus cultures increased antioxidant activity. This improvement in oxidative activity was positively correlated with the potential to reduce UC in vivo.

Akkermansia muciniphila: biology, microbial ecology, host interactions and therapeutic potential

Akkermansia muciniphila is a gut bacterium that colonizes the gut mucosa, has a role in maintaining gut health and shows promise for potential therapeutic applications. The discovery of A. muciniphila as an important member of our gut microbiome, occupying an extraordinary niche in the human gut, has led to new hypotheses on gut health, beneficial microorganisms and host-microbiota interactions. This microorganism has established a unique position in human microbiome research, similar to its role in the gut ecosystem. Its unique traits in using mucin sugars and mechanisms of action that can modify host health have made A. muciniphila a subject of enormous attention from multiple research fields. A. muciniphila is becoming a model organism studied for its ability to modulate human health and gut microbiome structure, leading to commercial products, a genetic model and possible probiotic formulations. This Review provides an overview of A. muciniphila and Akkermansia genus phylogeny, ecophysiology and diversity. Furthermore, the Review discusses perspectives on ecology, strategies for harnessing beneficial effects of A. muciniphila for human mucosal metabolic and gut health, and its potential as a biomarker for diagnostics and prognostics.

Glial cell line-derived neurotrophic factor improves impaired colonic motility in experimental colitis mice through connexin 43

BACKGROUND

Colonic motility dysfunction is a common symptom of ulcerative colitis (UC), significantly affecting patients' quality of life. Evidence suggests that glial cell line-derived neurotrophic factor (GDNF) plays a role in restoring colonic function.

AIM

To investigate whether GDNF enhances aberrant colonic motility in mice with experimental colitis via connexin 43 (Cx43).

METHODS

An experimental colitis model was induced in male C57BL/6 mice using dextran sodium sulfate (DSS). The measurement of colonic transit time was conducted, and colon tissues were evaluated through transmission electron microscopy and hematoxylin and eosin staining. The mice were treated with exogenous GDNF and Gap 19, a selective Cx43 inhibitor. The Cx43 and GDNF levels were detected via immunofluorescence, immunohistochemistry, and real-time polymerase chain reaction. The levels of inflammatory markers, including interleukin-1β, tumor necrosis factor-α, interleukin-6, and C-reactive protein, were quantified using enzyme-linked immunosorbent assay.

RESULTS

Experimental colitis was successfully induced using DSS, and the findings exhibited that the colonic transit time was significantly delayed in colitis mice relative to the UC group (P < 0.01). GDNF treatment improved colonic transit time and alleviated intestinal inflammation in DSS-induced colitis mice (P < 0.05). In the UC + Gap19 + GDNF group, colitis symptoms, colonic transit time, and inflammatory marker levels remained comparable to those in the UC group, indicating that the therapeutic effects of GDNF in UC mice were blocked by Gap 19.

CONCLUSION

GDNF improves colonic motility in mice with experimental colitis through a partially Cx43-mediated mechanism. GDNF holds promise as a therapeutic option for improving colonic motility in patients with colitis.

Orlistat ameliorates lipid dysmetabolism in high-fat diet-induced mice via gut microbiota modulation

Orlistat reduces obesity by inhibiting gastrointestinal lipases, thereby blocking the absorption and accumulation of triglycerides in the intestine. It has been shown to improve lipid metabolism and alter intestinal microbial communities in animals and humans. However, the impact of Orlistat-induced changes in gut microbiota on obesity requires further investigation. In this study, we found that Orlistat significantly improved metabolic disorders, inhibited fat accumulation, and reshaped the structure of intestinal microbiota. Specifically, it reduced α diversity and increased the relative abundance of Verrucomicrobia and Akkermansia. Notably, antibiotic-induced gut microbiota depletion significantly weakened Orlistat's effect on improving metabolic disorders. Furthermore, microbiota transplanted from Orlistat-treated mice effectively alleviated lipid metabolic disorders caused by a high-fat diet. We also observed that Orlistat increased food intake in mice and inhibited the synthesis of appetite-regulating hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon (Gcg). However, antibiotic-depleted microbiota mitigated this inhibitory effect. Interestingly, although Orlistat altered the gut microbiota of mice, transplanting these microbiota did not inhibit the synthesis of appetite-regulating hormones. In summary, our results suggest that Orlistat can reshape the gut microbiota, and the altered gut microbiota works synergistically with Orlistat to improve metabolic disorders. This improvement is related to the increased abundance of Verrucomicrobia and Akkermansia.

Rubidium salt can effectively relieve the symptoms of DSS-induced ulcerative colitis

Inflammatory bowel disease (IBD) is a chronic condition that afflicts individuals repeatedly and cannot be cured at present, which has seriously affected the quality of life of patients. Minerals Containing Rubidium (MCR) from Guangxi Yuechengling, which Professor Zhao Lichun purified, were explored. Against this backdrop, the present study investigates the efficacy of rubidium salt in ulcerative colitis. Rubidium salt reduced levels of inflammatory markers and improved intestinal barrier function through the Elisa kit, immunohistochemistry, and qPCR. Next, we detected the level of short-chain fatty acid and found that the content of propanoic acid, butyric acid, and n-butyric acid increased after treatment with rubidium salt. We used fecal metagenomics to explore the underlying reasons further and found that rubidium salt significantly adjusted the structure of intestinal flora, increased the abundance of beneficial bacteria such as lactobacillus and bifidobacterium, and inhibited the abundance of harmful bacteria such as Enterobacteriaceae and Escherichia coli. We also learned that rubidium salt directly weakened pathogenic bacteria's infection and survival ability by reducing the expression of virulence factors such as fimH, invA, and hilA and virulence genes such as acrA and ompR. Overall, rubidium salt can reduce harmful bacteria and increase beneficial bacteria. The increased beneficial bacteria help enhance the gut barrier and regulate inflammatory factors by raising the levels of short-chain fatty acids. A strengthened gut barrier further stabilizes microbial homeostasis, ultimately alleviating ulcerative colitis.

Antioxidant Therapy in Inflammatory Bowel Diseases: How Far Have We Come and How Close Are We?

Inflammatory bowel diseases (IBD) pose a growing public health challenge with unclear etiology and limited efficacy of traditional pharmacological treatments. Alternative therapies, particularly antioxidants, have gained scientific interest. This systematic review analyzed studies from MEDLINE, Cochrane, Web of Science, EMBASE, and Scopus using keywords like "Inflammatory Bowel Diseases" and "Antioxidants." Initially, 925 publications were identified, and after applying inclusion/exclusion criteria-covering studies from July 2015 to June 2024 using murine models or clinical trials in humans and evaluating natural or synthetic substances affecting oxidative stress markers-368 articles were included. This comprised 344 animal studies and 24 human studies. The most investigated antioxidants were polyphenols and active compounds from medicinal plants (n = 242; 70.3%). The review found a strong link between oxidative stress and inflammation in IBD, especially in studies on nuclear factor kappa B and nuclear factor erythroid 2-related factor 2 pathways. However, it remains unclear whether inflammation or oxidative stress occurs first in IBD. Lipid peroxidation was the most studied oxidative damage, followed by DNA damage. Protein damage was rarely investigated. The relationship between antioxidants and the gut microbiota was examined in 103 animal studies. Human studies evaluating oxidative stress markers were scarce, reflecting a major research gap in IBD treatment. PROSPERO registration: CDR42022335357 and CRD42022304540.

Abdel-Wareth M, Hassan M. Helix pomatia mucin alleviates DSS-induced colitis in mice: Unraveling the cross talk between microbiota and intestinal chemokine

Gut microbiota imbalance and alterations in the chemokine-chemokine receptor interactions are pivotal in the initiation and advancement of ulcerative colitis (UC). The current UC treatments are prolonged, exhibit high recurrence rates, and may lead to colorectal cancer. So, this study explores the efficacy of Helix pomatia (H. pomatia) mucin in preventing DSS-induced UC. This research focuses on investigating the underlying mechanisms, such as oxidative stress, inflammation, and alterations in gut microbiota and chemokine-chemokine receptor interactions, to understand the anti-inflammatory and antioxidant characteristics of the mucin. Using 4 % DSS in drinking water, UC was induced in C57BL/6 mice. For seven days, mice were given oral doses of either H. pomatia mucin or sulfasalazine. The study assessed changes in oxidative stress, gut microbiota, and histopathology, along with expression of IL-6, CXCR4, CCR7, CXCL9, and CXCL10. The H. pomatia mucin exhibited unique contents, including high glycolic acid (200 ± 2.08 mg/L), collagen (88 ± 2.52 mg/L), allantoin (20 ± 2 mg/L), and concentrated vitamins and minerals. Treatment with H. pomatia mucin in high dose demonstrated reduction in DAI, an increase in fecal Firmicutes, and elevated expression of colonic CCR7, CXCL9, and CXCL10, accompanied by enhanced CXCR4 (75 %) and diminished IL-6 (1.33 %) immunostaining. It also alleviated oxidative stress, reduced fecal Bacteroidetes, and mitigated inflammation, indicating its potential efficacy against DSS-induced UC. In conclusion, H. pomatia mucin is a promising candidate that could be an effective adjuvant in the management and prophylaxis of UC.

Mechanisms of intestinal injury in polychaete Perinereis aibuhitensis caused by low-concentration fluorene pollution: Microbiome and metabonomic analyses

The polychaete Perinereis aibuhitensis is used for bioremediation; however, its ability to remove fluorene, a common environmental pollutant, from sediments remains unclear, especially at low concentrations of fluorene (10 mg/kg). In this study, we explored the mechanism of intestinal injury induced by low concentrations of fluorene and the reason intestinal injury is alleviated in high fluorene concentration groups (100 and 1000 mg/kg) using histology, ecological biomarkers, gut microbiome, and metabolic response analyses. The results show that P. aibuhitensis showed high tolerance to fluorene in sediments, with clearance rates ranging 25-50 %. However, the remediation effect at low fluorene concentrations (10 mg/kg) was poor. This is attributed to promoting the growth of harmful microorganisms such as Microvirga, which can cause metabolic disorders, intestinal flora imbalances, and the generation of harmful substances such as 2-hydroxyfluorene. These can result in severe intestinal injury in P. aibuhitensis, reducing its fluorene clearance rate. However, high fluorene concentrations (100 and 1000 mg/kg) may promote the growth of beneficial microorganisms such as Faecalibacterium, which can replace the dominant harmful microorganisms and improve metabolism to reverse the intestinal injury caused by low fluorene concentrations, ultimately restoring the fluorene-removal ability of P. aibuhitensis. This study demonstrates an effective method for evaluating the potential ecological risks of fluorene pollution in marine sediments and provides guidance for using P. aibuhitensis for remediation.

Lianweng Granules Alleviate Intestinal Barrier Damage via the IL-6/STAT3/PI3K/AKT Signaling Pathway with Dampness-Heat Syndrome Diarrhea

Dampness-heat syndrome diarrhea (DHSD) is a common clinical disease with a high prevalence but still has no satisfactory therapeutic medicine, so the search for a safe and effective drug candidate is ongoing. This study aims to explore the efficacy and mechanisms of Lianweng granules (LWG) in the treatment of DHSD and to identify the blood transport components of LWG. We assessed the efficacy of LWG in DHSD by various in vivo metrics such as body weight, disease activity index (DAI), histopathologic examination, intestinal barrier function, levels of inflammatory, apoptotic biomarkers, and oxidative stress. We identified the blood components of LWG using ultra-high performance liquid chromatography-mass spectrometry/mass spectrometry (UHPLC-MS/MS), and the resolved key components were used to explore the relevant targets. We next predicted the potential mechanisms of LWG in treating DHSD using network pharmacology and molecular docking based on the relevant targets. Finally, the mechanisms were validated in vivo using RT-qPCR, Western blotting, ELISA, and immunofluorescence and evaluated in vitro using Cell Counting Kit-8 (CCK-8), small interfering RNA, cellular enthusiasm transfer assay (CETSA), and drug affinity response target stability (DARTS). Ninety-one pharmacodynamic components of LWG enter the bloodstream and exert possible therapeutic effects. In vivo, LWG treatment improved body weight, reduced colonic injury and DAI scores, lowered inflammation, oxidative stress, and apoptosis markers, and partially restored intestinal barrier function in DHSD mice. Guided by network pharmacology and molecular docking, it is suggested that LWG may exert therapeutic effects by inhibiting IL-6/STAT3/PI3K/AKT signaling. LWG significantly decreased the expression of IL-6, p-STAT3, p-PI3K, p-AKT, and other proteins. These findings were supported by in vitro experiments, where CETSA, DARTS, and siRNA evidenced LWG's targeting of STAT3. LWG targeted STAT3 to inhibit inflammation, oxidative stress, and apoptosis in the colon, thereby restoring the intestinal barrier function to some extent and exerting a therapeutic effect on DHSD.