Inhibiting Ferroptosis: A Novel Approach for Ulcerative Colitis Therapeutics

Selenium alleviates dextran sulfate sodium-induced colitis and inhibits ferroptosis of intestinal epithelial cells via upregulating glutathione peroxidase 4

BACKGROUND AND AIM

Selenium, an essential micronutrient for humans, has been shown to be protective against ulcerative colitis (UC), but the exact mechanism remains unclear. The role of selenium, protecting against ferroptosis of intestinal epithelial cells (IECs) in colitis, was investigated in this current study.

METHODS

Serum selenium level and ferroptosis-related gene expression in the colonic mucosa were measured in UC patients and healthy controls. The effects of sodium selenite supplementation on experimental colitis were investigated in dextran sulfate sodium (DSS)-treated mice. The influence of sodium selenite on IEC ferroptosis was evaluated through assessing cell death rate, intracellular ferrous iron content, lipid reactive oxygen species level, and mitochondrial membrane damage of DSS-treated Caco-2 cells. Moreover, glutathione peroxidase 4 (GPX4) and acyl-CoA synthetase long-chain family member 4, ferroptosis-related genes, were detected in Caco-2 cells and mouse intestines.

RESULTS

Serum selenium was decreased in UC patients in comparison with healthy individuals. Additionally, serum selenium level was negatively correlated with disease activity and was associated with clinical inflammation and nutrition indicators. The expression of GPX4 in the mucosa of UC was positively correlated with serum selenium level. The in vivo experiments showed that selenium treatment ameliorated DSS-induced colitis and inhibited ferroptosis in IECs. The in vitro results suggested that selenium supplementation inhibited DSS-induced ferroptosis in Caco-2 cells. GPX4 was upregulated after selenium supplementation both in vivo and in vitro.

CONCLUSIONS

Serum selenium level was associated with IEC ferroptosis in UC patients. Selenium supplementation alleviates DSS-induced colitis and inhibits ferroptosis in IECs by upregulating the expression of GPX4.

Dipeptidyl peptidase 4: A predictor of ferroptosis in ulcerative colitis

BACKGROUND

With its rapidly increasing incidence and prevalence, ulcerative colitis (UC) has become a major global health challenge. Recent evidence suggests that ferroptosis plays a significant role in the development of UC. However, the relationship between ferroptosis and the progression of UC needs to be extensively studied.

METHODS

The differentially expressed genes in UC patients were screened from the GEO database. The ferroptosis-related genes were obtained from FErrDB and GeneCards. The UC subtypes were identified with the R package "CancerSubtype" and evaluated with consensus clustering (CC) to identify gene expression patterns in patients with UC. The key genes were detected with qRT-PCR, Western blot, and immunohistochemistry in vitro and in vivo models. Ferroptosis was identified with western blotting on ferrotic-associated proteins and staining on Fe2+ with commercial FerroOrange kits.

RESULTS

Dipeptidyl peptidase 4 (DPP4), also known as CD26, is a potential biomarker for ferroptosis in UC patients. Transcriptome sequencing data showed a positive correlation between decreased DPP4 expression and proinflammatory cytokines such as TNF-α, IL-6, and IL-β, as well as immune cell infiltration in the colon tissues of UC patients. Furthermore, DPP4 was strongly associated with ferroptosis biomarkers, particularly in Subtype 2 of UC. Interestingly, our study also found that DPP4 expression was significantly reduced in RSL3-treated ferroptotic intestinal epithelial cells, more so than in LPS-treated cell models. Inhibition of DPP4 had a significant impact on the expression of ferroptotic biomarkers. Additionally, DPP4 expression was decreased in the colon tissues of DSS-treated mice, and the ferroptosis inhibitor Ferritin-1 effectively counteracted the effects of DSS on immune cell infiltration, colon length, and DPP4 expression.

CONCLUSIONS

DPP4 can serve as a biomarker for ferroptosis in the diagnosis and management of UC.

GPX4 restricts ferroptosis of NKp46+ILC3s to control intestinal inflammation

Group 3 innate lymphoid cells (ILC3s) are essential for both pathogen defense and tissue homeostasis in the intestine. Dysfunction of ILC3s could lead to increased susceptibility to intestinal inflammation. However, the precise mechanisms governing the maintenance of intestinal ILC3s are yet to be fully elucidated. Here, we demonstrated that ferroptosis is vital for regulating the survival of intestinal ILC3. Ferroptosis-related genes, including GPX4, a key regulator of ferroptosis, were found to be upregulated in intestinal mucosal ILC3s from ulcerative colitis patients. Deletion of GPX4 resulted in a decrease in NKp46+ILC3 cell numbers, impaired production of IL-22 and IL-17A, and exacerbated intestinal inflammation in a T cell-independent manner. Our mechanistic studies revealed that GPX4-mediated ferroptosis in NKp46+ILC3 cells was regulated by the LCN2-p38-ATF4-xCT signaling pathway. Mice lacking LCN2 in ILC3s or administration of a p38 pathway inhibitor exhibited similar phenotypes of ILC3 and colitis to those observed in GPX4 conditional knock-out mice. These observations provide novel insights into therapeutic strategies for intestinal inflammation by modulating ILC3 ferroptosis.

Harnessing nature's pharmacy: investigating natural compounds as novel therapeutics for ulcerative colitis

Backgrounds

Ulcerative colitis (UC) is a form of chronic inflammatory bowel disease, and UC diagnosis rates continue to rise throughout the globe. The research and development of new drugs for the treatment of UC are urgent, and natural compounds are an important source. However, there is a lack of systematic summarization of natural compounds and their mechanisms for the treatment of UC.

Methods

We reviewed the literature in the databases below from their inception until July 2023: Web of Science, PubMed, China National Knowledge Infrastructure, and Wanfang Data, to obtain information on the relationship between natural compounds and UC.

Results

The results showed that 279 natural compounds treat UC through four main mechanisms, including regulating gut microbiota and metabolites (Mechanism I), protecting the intestinal mucosal barrier (Mechanism II), regulating intestinal mucosal immune response (Mechanism III), as well as regulating other mechanisms (Mechanism Ⅳ) such as cellular autophagy modulation and ferroptosis inhibition. Of these, Mechanism III is regulated by all natural compounds. The 279 natural compounds, including 62 terpenoids, 57 alkaloids, 52 flavonoids, 26 phenols, 19 phenylpropanoids, 9 steroids, 9 saponins, 8 quinonoids, 6 vitamins, and 31 others, can effectively ameliorate UC. Of these, terpenoids, alkaloids, and flavonoids have the greatest potential for treating UC. It is noteworthy to highlight that a total of 54 natural compounds exhibit their therapeutic effects by modulating Mechanisms I, II, and III.

Conclusion

This review serves as a comprehensive resource for the pharmaceutical industry, researchers, and clinicians seeking novel therapeutic approaches to combat UC. Harnessing the therapeutic potential of these natural compounds may significantly contribute to the improvement of the quality of life of patients with UC and promotion of disease-modifying therapies in the future.

N-Acetylcysteine Alleviates Necrotizing Enterocolitis by Depressing SESN2 Expression to Inhibit Ferroptosis in Intestinal Epithelial Cells

Abstract-Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease in neonates, and effective strategies to prevent and treat NEC are still lacking. Studies have shown that N-acetylcysteine (NAC) has protective effects against NEC, however, the specific mechanism underlying its effects on intestinal functions remains unclear. Recently, NAC has been shown to suppress ferroptosis in many diseases, while it is unclear whether the beneficial effects of NAC on NEC are related to ferroptosis. In this study, we revealed that ferroptosis was significantly induced in intestinal samples from infants with NEC. NAC alleviated intestinal inflammation, barrier damage and ferroptosis in multifactorial NEC models in vivo and in vitro. Sestrin2 (SESN2) was identified as an important mediator of NAC-induced ferroptosis resistance in intestinal epithelial cells. Furthermore, SESN2 knockdown inhibited the inflammatory response, alleviated barrier damage and ferroptosis in intestinal epithelial cells and enhanced the protective effects of NAC to a certain extent. Conversely, cells overexpressing SESN2 showed the opposite changes. In summary, our study demonstrated that NAC attenuates NEC progression by decreasing SESN2 expression to inhibit ferroptosis in intestinal epithelial cells, suggesting that NAC might be an effective clinical treatment for NEC.

Ferroptosis: a new mechanism of traditional Chinese medicine for treating ulcerative colitis

Ulcerative colitis (UC), a subtype of inflammatory bowel disease, manifests with symptoms such as abdominal pain, diarrhea, and mucopurulent, bloody stools. The pathogenesis of UC is not fully understood. At present, the incidence of UC has increased significantly around the world. Conventional therapeutic arsenals are relatively limited, with often poor efficacy and many adverse effects. In contrast, traditional Chinese medicine (TCM) holds promise due to their notable effectiveness, reduced recurrence rates, and minimal side effects. In recent years, significant progress has been made in the basic research on TCM for UC treatment. It has been found that the inhibition of ferroptosis through the intervention of TCM can significantly promote intestinal mucosal healing and reverse UC. The mechanism of action involves multiple targets and pathways.

Aim of the review

This review summarizes the experimental studies on the targeted regulation of ferroptosis by TCM and its impact on UC in recent years, aiming to provide theoretical basis for the prevention, treatment, and further drug development for UC.

Results

Ferroptosis disrupts antioxidant mechanisms in intestinal epithelial cells, damages the intestinal mucosa, and participates in the pathological process of UC. TCM acts on various pathways such as Nrf2/HO-1 and GSH/GPX4, blocking the pathological progression of ferroptosis in intestinal epithelial cells, inhibiting pathological damage to the intestinal mucosa, and thereby alleviating UC.

Conclusion

The diverse array of TCM single herbs, extracts and herbal formulas facilitates selective and innovative research and development of new TCM methods for targeting UC treatment. Although progress has been made in studying TCM compound formulas, single herbs, and extracts, there are still many issues in clinical and basic experimental designs, necessitating further in-depth scientific exploration and research.

Celecoxib alleviates the DSS-induced ulcerative colitis in mice by enhancing intestinal barrier function, inhibiting ferroptosis and suppressing apoptosis

INTRODUCTION

Ulcerative colitis (UC) is an inflammatory intestine disease characterized by dysfunction of the intestinal mucosal barrier, ferroptosis, and apoptosis. Previous researches suggest that celecoxib, a nonsteroidal anti-inflammatory drug, holds promise in alleviating inflammation in UC. Therefore, this study aims to investigate the effects and mechanisms of celecoxib in UC.

METHODS

To identify ferroptosis-related drugs and genes associated with UC, we utilized the Gene Expression Omnibus (GEO), FerrDb databases, and DGIdb database. Subsequently, we established a 2.5% DSS (Dextran sulfate sodium)-induced colitis model in mice and treated them with 10 mg/kg of celecoxib to validate the bioinformatics results. We evaluated histological pathologies, inflammatory response, intestinal barrier function, ferroptosis markers, and apoptosis regulators.

RESULTS

Celecoxib treatment significantly ameliorated DSS-induced UC in mice, as evidenced by the body weight change curve, colon length change curve, disease activity index (DAI) score, and histological index score. Celecoxib treatment reduced the level of pro-inflammatory factors and promoted the expressions of intestinal tight junction proteins such as Claudin-1 and Occludin, thereby restoring the integrity of the intestinal mucosal barrier. Furthermore, celecoxib treatment reversed the ferroptosis characteristics in DSS-induced mice by increasing glutathione (GSH), decreasing malondialdehyde (MDA), and increasing the expression of GPX-4 and xCT. Additionally, apoptosis was induced in mice with UC, as evidenced by increased Caspase3, BAD, P53, BAX, Caspase9 and Aifm1 production, and decreased expression of BCL-XL and BCL2. Celecoxib treatment significantly reversed the apoptotic changes in DSS-induced mice.

CONCLUSION

Our findings suggest that celecoxib effectively treats DSS-induced UC in mice by inhibiting ferroptosis and apoptosis.

Emerging role of exosomes in ulcerative colitis: Targeting NOD-like receptor family pyrin domain containing 3 inflammasome

Ulcerative colitis (UC) is a chronic recurrent inflammatory bowel disease. Despite ongoing advances in our understanding of UC, its pathogenesis is yet unelucidated, underscoring the urgent need for novel treatment strategies for patients with UC. Exosomes are nanoscale membrane particles that mediate intercellular communication by carrying various bioactive molecules, such as proteins, RNAs, DNA, and metabolites. The NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is a cytosolic tripartite protein complex whose activation induces the maturation and secretion of proinflammatory cytokines interleukin-1β (IL-1β) and IL-18, triggering the inflammatory response to a pathogenic agent or injury. Growing evidence suggests that exosomes are new modulators of the NLRP3 inflammasome, with vital roles in the pathological process of UC. Here, recent evidence is reviewed on the role of exosomes and NLRP3 inflammasome in UC. First, the dual role of exosomes on NLRP3 inflammasome and the effect of NLRP3 inflammasome on exosome secretion are summarized. Finally, an outlook on the directions of exosome-NLRP3 inflammasome crosstalk research in the context of UC is proposed and areas of further research on this topic are highlighted.

Natural compounds target programmed cell death (PCD) signaling mechanism to treat ulcerative colitis: a review

Ulcerative colitis (UC) is a nonspecific inflammatory bowel disease characterized by abdominal pain, bloody diarrhea, weight loss, and colon shortening. However, UC is difficult to cure due to its high drug resistance rate and easy recurrence. Moreover, long-term inflammation and increased disease severity can lead to the development of colon cancer in some patients. Programmed cell death (PCD) is a gene-regulated cell death process that includes apoptosis, autophagy, necroptosis, ferroptosis, and pyroptosis. PCD plays a crucial role in maintaining body homeostasis and the development of organs and tissues. Abnormal PCD signaling is observed in the pathological process of UC, such as activating the apoptosis signaling pathway to promote the progression of UC. Targeting PCD may be a therapeutic strategy, and natural compounds have shown great potential in modulating key targets of PCD to treat UC. For instance, baicalin can regulate cell apoptosis to alleviate inflammatory infiltration and pathological damage. This review focuses on the specific expression of PCD and its interaction with multiple signaling pathways, such as NF-κB, Nrf2, MAPK, JAK/STAT, PI3K/AKT, NLRP3, GPX4, Bcl-2, etc., to elucidate the role of natural compounds in targeting PCD for the treatment of UC. This review used (ulcerative colitis) (programmed cell death) and (natural products) as keywords to search the related studies in PubMed and the Web of Science, and CNKI database of the past 10 years. This work retrieved 72 studies (65 from the past 5 years and 7 from the past 10 years), which aims to provide new treatment strategies for UC patients and serves as a foundation for the development of new drugs.

Advancing the frontiers of colorectal cancer treatment: harnessing ferroptosis regulation

In recent years, colorectal cancer incidence and mortality have increased significantly due to poor lifestyle choices. Despite the development of various treatments, their effectiveness against advanced/metastatic colorectal cancer remains unsatisfactory due to drug resistance. However, ferroptosis, a novel iron-dependent cell death process induced by lipid peroxidation and elevated reactive oxygen species (ROS) levels along with reduced activity of the glutathione peroxidase 4 (GPX4) antioxidant enzyme system, shows promise as a therapeutic target for colorectal cancer. This review aims to delve into the regulatory mechanisms of ferroptosis in colorectal cancer, providing valuable insights into potential therapeutic approaches. By targeting ferroptosis, new avenues can be explored for innovative therapies to combat colorectal cancer more effectively. In addition, understanding the molecular pathways involved in ferroptosis may help identify biomarkers for prognosis and treatment response, paving the way for personalized medicine approaches. Furthermore, exploring the interplay between ferroptosis and other cellular processes can uncover combination therapies that enhance treatment efficacy. Investigating the tumor microenvironment's role in regulating ferroptosis may offer strategies to sensitize cancer cells to cell death induction, leading to improved outcomes. Overall, ferroptosis presents a promising avenue for advancing the treatment of colorectal cancer and improving patient outcomes.

Electroacupuncture Reduces Inflammatory Bowel Disease in Obese Mice by Activating the Nrf2/HO-1 Signaling Pathways and Repairing the Intestinal Barrier

Background

Electroacupuncture (EA) is used to treat inflammatory bowel disease (IBD). Nevertheless, the precise mechanisms by which this approach safeguards against obesity-induced intestinal barrier damage has not been fully understood.

Objective

This study aimed to assess whether EA could ameliorate intestinal barrier damage that had been reversed in a mouse model of obesity induced by a high-fat diet (HFD) and whether this repair is correlated with ferroptosis and gut microbiota enhancement.

Methods

To assess the potential of EA to prevent obesity and restore the intestinal barrier, we divided in C57BL/6J mice into two groups; one was fed with HFD and another one with a normal diet. Samples of stool, blood, fat, and intestinal epithelium were then evaluated, along with body weight.

Results

Following EA, we observed a significant reduction in body weight, fat accumulation, and serum triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) levels; an increase was seen in high-density lipoprotein cholesterol (HDL-C) levels. EA also activated the Nrf2 signaling pathway; upregulated the expression of GPX4, FTH1, and SLC7A11; and downregulated the expression of TFR1. In addition, the administration of EA resulted in a notable modification of the gut microbiota composition, characterized by a decrease in the Firmicutes to Bacteroidetes ratio.

Conclusion

EA had beneficial effects on weight loss and showed potential ability to repair the intestinal barrier by activating the Nrf2 signaling pathway, inhibiting intestinal inflammation and ferroptosis, and regulating the intestinal microbiota to treat IBD caused by HFD-induced obesity.

Evaluation of the Mechanism of Sinomenii Caulis in Treating Ulcerative Colitis based on Network Pharmacology and Molecular Docking

BACKGROUND

Studies have indicated that Sinomenii Caulis (SC) has several physiological activities, such as anti-inflammatory, anti-cancer, immunosuppression, and so on. SC is currently widely used in the treatment of rheumatoid arthritis, skin disease, and other diseases. However, the mechanism of SC in the treatment of ulcerative colitis (UC) remains unclear.

AIMS

To predict the active components of SC and determine the mechanism of SC on UC.

METHODS

Active components and targets of SC were screened and obtained by TCMSP, PharmMapper, and CTD databases. The target genes of UC were searched from GEO (GSE9452), and DisGeNET databases. Based on the String database, Cytoscape 3.7.2 software, and David 6.7 database, we analyzed the relationship between SC active components and UC potential targets or pathways. Finally, identification of SC targets in anti-UC by molecular docking. GROMACS software was used to perform molecular dynamics simulations of protein and compound complexes and to perform free energy calculations.

RESULTS

Six main active components, 61 potential anti-UC gene targets, and the top 5 targets with degree value are IL6, TNF, IL1β, CASP3, and SRC. According to GO enrichment analysis, the vascular endothelial growth factor receptor and vascular endothelial growth factor stimulus may be relevant biological processes implicated in the treatment of UC by SC. The KEGG pathway analysis result was mainly associated with the IL-17, AGE-RAGE, and TNF signaling pathways. Based on molecular docking results, beta-sitosterol, 16-epi-Isositsirikine, Sinomenine, and Stepholidine are strongly bound to the main targets. Molecular dynamics simulation results showed that IL1B/beta-sitosterol and TNF/16-epi-Isositsirikine binding was more stable.

CONCLUSION

SC can play a therapeutic role in UC through multiple components, targets, and pathways. The specific mechanism of action needs to be further explored.

Macrophages in ulcerative colitis: A perspective from bibliometric and visual analysis

Objectives

Despite the many reported studies on macrophages in ulcerative colitis (UC), the overall research trends in this field are unclear. This study evaluates the research trends and hotspots regarding macrophages in UC using bibliometric analysis.

Methods

A systematic search was conducted in the Web of Science database to identify publications related to macrophages in UC from 2012 to 2021. R package 'bibliometrix', VOSviewers, CiteSpace and Microsoft Excel were utilised for the bibliometric analysis.

Results

1074 articles published between 2012 and 2021 were analysed. The number of publications on macrophages in UC showed a consistently increasing trend, with USA and China as the leading contributors to this field. Notably, Georgia State University and Nanjing University contributed significantly to this field. Among the authors, Wang Y had the highest productivity, while Wu X received the most citations. The journal Gut was identified as the most authoritative journal in this field. Co-citation analysis revealed that the exploration of the mechanisms of macrophages in UC through in vivo and in vitro experiments was the primary focus of research. Moreover, the emerging research hotspots included keywords such as 'macrophage polarization', 'gut microbiota' and 'NLRP3 inflammasome'.

Conclusions

Research on macrophages in UC holds significant value and practical implications. Additionally, China demonstrated prolific output in this field, while the USA had the most influential contributions. Currently, research hotspots are centred around the modulation of gut microbiota to regulate macrophage polarization and macrophage pyroptosis as potential strategies for mitigating UC.

Vitronectin Destroyed Intestinal Epithelial Cell Differentiation through Activation of PDE4-Mediated Ferroptosis in Inflammatory Bowel Disease

Objective

Vitronectin (VTN) has been reported to trigger cell pyroptosis to aggravate inflammation in our previous study. However, the function of VTN in inflammatory bowel disease (IBD) remains to be addressed.

Methods

Real-time PCR and western blotting were performed to analyze VTN-regulated intestinal epithelial cell (IEC) differentiation through ferroptosis, and immunofluorescence (IF), luciferase, and chromatin immunoprecipitation were used to identify whether VTN-modulated ferroptosis is dependent on phosphodiesterase 4 (PDE4)/protein kinase A (PKA)/cyclic adenosine monophosphate-response element-binding protein (CREB) cascade pathway. In vivo experiment in mice and a pilot study in patients with IBD were used to confirm inhibition of PDE4-alleviated IECs ferroptosis, leading to cell differentiation during mucosal healing.

Results

Herein, we found that caudal-related homeobox transcription factor 2-mediated IECs differentiation was impaired in response to VTN, which was attributed to enhanced ferroptosis characterized by decreased glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 expression. Inhibition of ferroptosis in IECs rescued the inhibitory effect of VTN on cell differentiation. Further analysis showed that VTN triggered phosphorylation of PDE4, leading to inhibit PKA/CREB activation and CREB nuclear translocation, which further reduced GPX4 transactivation. Endogenous PKA interacted with CREB, and this interaction was destroyed in response to VTN stimulation. What is more, overexpression of CREB in CaCO₂ cells overcame the promotion of VTN on ferroptosis. Most importantly, inhibition of PDE4 by roflumilast or dipyridamole could alleviate dextran sulfate sodium-induced colitis in mice and in a pilot clinical study confirmed by IF.

Conclusions

These findings demonstrated that highly expressed VTN disrupted IECs differentiation through PDE4-mediated ferroptosis in IBD, suggesting targeting PDE4 could be a promising therapeutic strategy for patients with IBD.

Human umbilical cord mesenchymal stem cells derived exosome shuttling mir-129-5p attenuates inflammatory bowel disease by inhibiting ferroptosis

BACKGROUND

Ferroptosis, a unique form of non-apoptotic cell death, is dependent on iron and lipoperoxidation, and has been shown to be associated with the pathogenesis of inflammatory bowel disease (IBD). Human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Ex) are involved in cell survival, immune conditioning, and damage repair. However, the relationship between hucMSC-Ex, IBD, and ferroptosis is unknown. This paper explores the role of hucMSC-Ex in the repair of IBD through the regulation of the ferroptosis signaling pathway.

RESULTS

In this study, we used small RNA sequencing to find that miR-129-5p was highly expressed in hucMSC-Ex, and by predicting its targeting to ACSL4, we verified the effect of miR-129-5p on mice IBD in vitro and human colonic epithelial cells (HCoEpiC) in vivo. We found that miR-129-5p reduces ferroptosis in intestinal epithelial cells by targeting ACSL4 to repair IBD, which provides new strategies for the prevention and treatment of IBD.

CONCLUSION

In conclusion, our results demonstrate that hucMSC-Ex relieves IBD by targeting ACSL4 with miR-129-5p to inhibit lipid peroxidation (LPO) and ferroptosis, reducing intestinal inflammation and repairing damages. Mechanism of hucMSC-Ex inhibiting ferroptosis in intestinal epithelial cells. System Xc^- mediates the transport of extracellular cystine into the cell, which gets reduced to cysteine to participate in GSH-mediated metabolism. GPX4 strongly inhibits ferroptosis by helping scavenge reactive oxygen species. The depletion of GSH correlates with decreased GPX4, and the imbalance of the antioxidant system leads to the formation of toxic phospholipid hydroperoxide, which promotes the occurrence of ferroptosis with the participation of irons. HucMSC-Ex has the ability to relieve GSH and GPX4 depletion and repair the intracellular antioxidant system. Ferric ions enter the cytosol through DMT1 and participate in lipid peroxidation. HucMSC-Ex can reduce the expression of DMT1 and alleviate this process. HucMSC-Ex-derived miR-129-5p targets ACSL4 and reduces the expression of ACSL4, an enzyme that mediates the conversion of PUFAs into phospholipids in intestinal epithelial cells, and is a positive regulator of lipid peroxidation.

ABBREVIATIONS

GSH, glutathione; GPX4, glutathione peroxidase 4; GSSG, oxidized glutathione; DMT1, divalent metal transporter 1; ACSL4, acyl-CoA synthetase long-chain family member 4; PUFAs, polyunsaturated fatty acids; ALOXs, lipoxygenases; CoA, coenzyme A; PL, phospholipid; PLOOH, hydroperoxides, LOH, phospholipid alcohols; LPO, lipid peroxidation.

Kumatakenin inhibited iron-ferroptosis in epithelial cells from colitis mice by regulating the Eno3-IRP1-axis

Inhibition of epithelial ferroptosis in colonic tissues relieved clinical symptoms and improved endoscopic presentations in inflammatory bowel disease (IBD). Kumatakenin, the main ingredient of traditional Chinese medicinal cloves and Alpinia purpurata, is reported to possess therapeutic benefits. However, whether kumatakenin could inhibit ferroptosis and further alleviate colitis remains unclear. Here, we measured the effects of kumatakenin on ferroptosis of colonic epithelial cells from colitis mice. The colitis model was induced in mice by oral intake of 2.5% dextran sulfate sodium in drinking water. RNA sequencing was performed to investigate the mechanism underlying kumatakenin-mediated effects on colitis. The results showed that different doses of kumatakenin significantly alleviated symptoms and suppressed intestinal inflammation in the colitis mouse model. Kumatakenin supplementation decreased cellular iron levels and suppressed ferroptosis in epithelial cells from colitis mice. RNA sequencing, qPCR, and pharmacological inhibition assays showed that kumatakenin reduced cellular iron levels and suppressed ferroptosis in epithelial cells from colitis mice at least partially by upregulating expression of enolase (Eno-3). Furthermore, kumatakenin decreased iron levels in epithelial cells by modulating the Eno3-iron regulatory protein (IRP1) axis. Molecular docking results revealed that kumatakenin could bind Eno3 via hydrogen bonding with the amino acid residues Thr208, Val206, and Pro203. This work will provide a scientific basis for the clinical use of kumatakenin in the treatment of colitis.

Identification of cuproptosis-associated subtypes and signature genes for diagnosis and risk prediction of Ulcerative colitis based on machine learning

Background

Ulcerative colitis (UC) is a chronic and debilitating inflammatory bowel disease that impairs quality of life. Cuproptosis, a recently discovered form of cell death, has been linked to many inflammatory diseases, including UC. This study aimed to examine the biological and clinical significance of cuproptosis-related genes in UC.

Methods

Three gene expression profiles of UC were obtained from the Gene Expression Omnibus (GEO) database to form the combined dataset. Differential analysis was performed based on the combined dataset to identify differentially expressed genes, which were intersected with cuproptosis-related genes to obtain differentially expressed cuproptosis-related genes (DECRGs). Machine learning was conducted based on DECRGs to identify signature genes. The prediction model of UC was established using signature genes, and the molecular subtypes related to cuproptosis of UC were identified. Functional enrichment analysis and immune infiltration analysis were used to evaluate the biological characteristics and immune infiltration landscape of signature genes and molecular subtypes.

Results

Seven signature genes (ABCB1, AQP1, BACE1, CA3, COX5A, DAPK2, and LDHD) were identified through the machine learning algorithms, and the nomogram built from these genes had excellent predictive performance. The 298 UC samples were divided into two subtypes through consensus cluster analysis. The results of the functional enrichment analysis and immune infiltration analysis revealed significant differences in gene expression patterns, biological functions, and enrichment pathways between the cuproptosis-related molecular subtypes of UC. The immune infiltration analysis also showed that the immune cell infiltration in cluster A was significantly higher than that of cluster B, and six of the characteristic genes (excluding BACE1) had higher expression levels in subtype B than in subtype A.

Conclusions

This study identified several promising signature genes and developed a nomogram with strong predictive capabilities. The identification of distinct subtypes of UC enhances our current understanding of UC's underlying pathogenesis and provides a foundation for personalized diagnosis and treatment in the future.

Xue-Jie-San restricts ferroptosis in Crohn's disease via inhibiting FGL1/NF-κB/STAT3 positive feedback loop

Crohn's disease (CD) is an incurable inflammatory bowel disease due to unclear etiology and pathogenesis. Accumulating evidences have shown the harmful role of ferroptosis in CD onset and development. Additionally, fibrinogen-like protein 1 (FGL1) has been verified to be a potential therapeutic target of CD. Xue-Jie-San (XJS) is an effective prescription for treating CD. However, its therapeutic mechanism has not been fully elucidated. This study aimed to determine whether XJS alleviating CD via regulating ferroptosis and FGL1 expression. A colitis rat model was induced by 2,4,6-trinitrobenzene sulfonic acid and treated with XJS. The disease activity indices of the colitis rats were scored. Histopathological damage was assessed using HE staining. ELISA was performed to examine inflammatory cytokines. Transmission electron microscopy was utilized to observe ultrastructure changes in intestinal epithelial cells (IECs). Iron load was evaluated by examining iron concentrations, the expressions of FPN, FTH and FTL. Lipid peroxidation was investigated through detecting the levels of ROS, 4-HNE, MDA and PTGS2. Furthermore, the SLC7A11/GSH/GPX4 antioxidant system and FGL1/NF-κB/STAT3 signaling pathway were examined. The results showed that colitis was dramatically ameliorated in the XJS-treated rats as evidenced by relief of clinical symptoms and histopathological damages, downregulation of pro-inflammatory cytokines IL-6, IL-17 and TNF-α, and upregulation of anti-inflammatory cytokine IL-10. Furthermore, XJS administration led to ferroptosis inhibition in IECs by reducing iron overload and lipid peroxidation. Mechanistically, XJS enhanced the SLC7A11/GSH/GPX4 antioxidant system negatively regulated by the FGL1/NF-κB/STAT3 positive feedback loop. In conclusion, XJS might restrain ferroptosis in IECs to ameliorate experimental colitis by inhibition of FGL1/NF-κB/STAT3 positive feedback loop.

Revealing immune infiltrate characteristics and potential diagnostic value of immune-related genes in ulcerative colitis: An integrative genomic analysis

Objectives

Ulcerative colitis (UC) is an autoimmune disease of the colon. The aim of this study was to explore the characteristics of immune infiltrates in UC patients and identify immune-related diagnostic biomarkers for UC.

Methods

Three gene expression profiles were acquired from the GEO database, followed by identification of differentially expressed genes (DEGs) by Linear Modeling of Microarray Data. Enrichment analysis of Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Disease Ontology (DO) were performed to analyze the biological functions of DEGs. Subsequently, the single sample gene set enrichment analysis (ssGSEA) was performed to identify immune infiltration characteristics of UC. Correlations between diagnostic genes and immune infiltration were explored to identify markers with the greatest diagnostic potential, and a UC diagnostic model was subsequently constructed. Finally, the prediction performance of the model was quantified by nomogram, non-correlated nomogram, and ROC curve.

Results

A total of 3111 DEGs (1,608 up-regulated and 1,503 down-regulated genes) were identified. DEGs were significantly involved in the immune system and UC-related pathways. Immune infiltration profiles of colonic tissue were significantly different between healthy individuals and UC patients. High proportions of resting of aDCs, B cells, CD8⁺ T cells, DCs, iDCs, Macrophages, Neutrophils, pDCs, T helper cells, Tfh, Th1 cells, Th2 cells, TIL and Treg were found in UC samples. A 5-gene based diagnostic prediction model was constructed and the results of nomogram, non-correlated nomogram and ROC curve suggested the powerful diagnostic value of the model.

Conclusions

This study identified the immune infiltrate characteristics and 5 immune-related genes for UC. The model based on the immune-related genes facilitates the early diagnosis of UC and provides a basis for the evaluation of the prognosis of UC.

Comprehensive analysis of cuproptosis-related genes in immune infiltration and diagnosis in ulcerative colitis

Objectives

Cuproptosis is a recently discovered form of programmed cell death; however, its role in ulcerative colitis (UC) remains a void.

Methods

Three gene expression profiles were acquired from the GEO database. Subsequently, the single sample gene set enrichment analysis (ssGSEA) was performed to identify the immune infiltration characteristics of UC. Correlation analysis between cuproptosis and immune infiltration was further conducted, and the cuproptosis-related genes were applied to construct a UC diagnostic model. Subsequently, analysis results of microarray data were experimentally validated by DSS-induced colitis in mice. Finally, therapeutic agents for the cuproptosis-related genes were screened owing to the gaping field of therapeutic agents on cuproptosis.

Results

Three gene expression profiles with 343 samples (290 UC and 53 healthy samples) were included. Immune infiltration revealed that UC patients had a higher level of DCs, B cells, CD8⁺ T cells, iDCs, Macrophages, neutrophils, pDCs, T helper cells, Tfh, Th1 cells, Th2 cells, TIL and Treg than normal subjects. Moreover, almost all cuproptosis-related genes were significantly negatively associated with immune infiltration in UC patients. The risk prediction model based on cuproptosis-related genes showed an excellent discrimination for UC. Animal experiments revealed significant alterations in genes essential for cuproptosis between DSS-induced colitis mice and healthy controls, providing experimental validation for the analysis results of microarray data. Further analysis revealed that latamoxef, vitinoin, clomipramine, chlorzoxazone, glibenclamide, pyruvic acid, clindamycin, medrysone, caspan, and flavin adenine dinucleotide might be the target agents for cuproptosis-related genes.

Conclusions

In conclusion, cuproptosis was significantly associated with immune infiltration in UC, and the cuproptosis-related genes showed an excellent discrimination for UC.

Ferroptosis, a Rising Force against Renal Fibrosis

Ferroptosis is a type of programmed cell death characterized by iron overload, oxidative stress, imbalance in lipid repair, and mitochondria-specific pathological manifestations. Growing number of molecular mechanisms and signaling pathways have been found to be involved in ferroptosis progression, including iron metabolism, amino acid metabolism, lipid metabolism, and energy metabolism. It is worth noting that ferroptosis is involved in the progression of fibrotic diseases such as liver cirrhosis, cardiomyopathy, and idiopathic pulmonary fibrosis, and inhibition of ferroptosis has acquired beneficial outcomes in rodent models, while studies on ferroptosis and renal fibrosis remains limited. Recent studies have revealed that targeting ferroptosis can effectively mitigate chronic kidney injury and renal fibrosis. Moreover, myofibroblasts suffer from ferroptosis during fiber and extracellular matrix deposition in the fibrotic cascade reaction and pharmacological modulation of ferroptosis shows great therapeutic effect on renal fibrosis. Here, we summarize the latest molecular mechanisms of ferroptosis from high-quality studies and review its therapeutic potential in renal fibrosis.