Macrophages in intestinal inflammation and resolution: a potential therapeutic target in IBD

Evaluating the anti-inflammatory and antioxidant efficacy of complementary and alternative medicines (CAM) used for management of inflammatory bowel disease: a comprehensive review

Inflammatory bowel disease (IBD) is a chronic autoimmune condition whose pathogenesis has not been fully elucidated, and current treatments are not definitive and often carry several side effects. The Complementary and Alternative Medicine (CAM) offers a new approach to conventional medicine. However, their clinical application and mechanisms remain limited.Objective: The aim of this review is to evaluate the anti-inflammatory, impact on microbiota and antioxidant efficacy of currently available CAM for IBD.Methods: The literature collection was obtained from Google Scholar, MEDLINE, PubMed and Web of Science (WOS). Studies in both human and animal models, published in English language between 2018 and 2024, were selected. Sixty-seven studies were included in the current review after inclusion and exclusion screening processes.Results: Mostly, studies showed significant anti-inflammatory, gut microbiota restoring, antioxidant effects of polyphenols, polysaccharides, emodin, short-chain fatty acids (SCFA; including butyrate, propionate and acetate), and probiotics although some contrasting results were noted. Current evidence shows that polyphenols exhibit the most consistent result in alleviating IBD pathophysiology, primarily due to their significant SCFA-elevating effect.Discussion: Future studies may focus on human studies, narrowing down on individual factors which may change natural product's metabolism. Further research studies are also essential to obtain therapeutic recommendations.

Inactivation of glutathione S-transferase alpha 4 blocks Enterococcus faecalis-induced bystander effect by promoting macrophage ferroptosis

Enterococcus faecalis-infected macrophages produce 4-hydroxynonenal (4-HNE) that mediates microbiota-induced bystander effect (MIBE) leading to colorectal cancer (CRC). Glutathione S-transferase alpha 4 (Gsta4), a specific detoxifying enzyme for 4-HNE, is overexpressed in human CRC and E. faecalis-induced murine CRC. However, the roles of Gsta4 in E. faecalis-induced colitis and CRC remain unclear. Herein, we demonstrate that Gsta4 is essential for MIBE by protecting macrophages from E. faecalis-induced ferroptosis. E. faecalis OG1RFSS was used to induce colitis in Gsta4-/- and Il10-/-/Gsta4-/- mice by orogastric gavage. Ferroptosis was assessed in Gsta4-deficient murine macrophages. We found that, unlike Il10-/- mice, Gsta4-/- and Il10-/-/Gsta4-/- mice colonized with E. faecalis failed to develop colitis or CRC. Immunofluorescent staining showed a reduction of macrophages in the lamina propria of E. faecalis-colonized Il10-/-/Gsta4-/- mice, as well as decreased Gpx4 expression, indicating the occurrence of ferroptosis. Ferroptosis was further confirmed in Gsta4-deficient murine macrophages infected with E. faecalis. Moreover, Gsta4 inactivation induced the upregulation of Hmox1 and phosphorylated c-Jun while blocked Nos2 expression, leading to the accumulation of intracellular ferrous iron, lipid peroxidation and, eventually, ferroptosis. Finally, Mapk8, as a ferroptosis driver, was remarkably elevated in E. faecalis-infected Gsta4-deficient macrophages. These results suggest that Gsta4 inactivation blocks MIBE by eliminating macrophages, thereby attenuates E. faecalis-induced colitis and CRC.

Andrographolide and its sulfated metabolite alleviated DSS-induced inflammatory bowel disease through regulating inflammation and immune via MAPK/NLRP3 pathways and the balance of Th17/Treg cells

Inflammatory Bowel Disease (IBD), is a chronic illness characterized by severe abdominal pain, diarrhea, and weight loss, seriously diminishing patients' quality of life. Andrographolide (AND), a natural diterpenoid from Andrographis paniculata, and its sulfated metabolite, andrographolide sodium bisulfite (ASB), have showed potential anti-inflammatory effects. However, their mechanism in IBD remains elusive. This study investigated the impact of AND and its sulfated derivative ASB, on inflammatory responses in IBD. Our findings revealed that AND and ASB significantly reduced disease activity index (DAI) scores and enhanced intestinal barrier function in dextran sodium sulfate (DSS)-induced mice, thereby ameliorating the course of IBD. Furthermore, AND and ASB inhibited both the mitogen-activated protein kinase (MAPK) and NLRP3 pathways to reduce the release of inflammatory cytokines IL-6 and TNF-α. This mechanism was accompanied by a restoration of immune balance through the modulation of T-helper 17 (Th17) and regulatory T (Treg) cells. The ability of AND and ASB to mitigate chronic inflammation and maintain immune equilibrium presented a promising therapeutic approach for IBD management. These findings suggested that AND and ASB might provide novel therapeutic approaches for IBD, thereby warranting further investigation into their clinical efficacy for disease treatment and maintenance of remission.

Inflammation-targeted delivery of probiotics for alleviation of colitis and associated cognitive disorders through improved vitality and colonization

Oral probiotic biotherapies hold significant promise for addressing intestinal inflammatory disorders. Nonetheless, due to the challenging pathological microenvironment of the gastrointestinal tract, it is difficult to achieve deliver probiotics in an inflammation-targeted manner while improving their intestinal colonization and minimizing the impact of gastrointestinal environment on their vitality. To address this, an innovative probiotics oral delivery system (EcN-Apt@HG) against ulcerative colitis (UC) was developed by conjugating IL-6 aptamer to the surface of EcN and subsequently encapsulating the probiotics in a hydrogel consisting of aldehyde-functionalized chondroitin sulfate (CS) and Poly(amidoamine) (PAMAM). As expected, the encapsulated EcN demonstrated resistance to gastrointestinal conditions, and the colonization duration of probiotics in the colon was enhanced via the preferential adhesion effect of IL-6 aptamer on the inflammatory site. The EcN-Apt@HG system restored the damaged mucosal layer, suppressed hyperactive immune responses, and reshaped the dysbiosis of intestinal microflora, thereby synergistically alleviating dextran sulfate sodium (DSS)-induced colitis. Notably, EcN-Apt@HG significantly alleviated depression-like behaviors and cognitive impairment in colitis mice through gut-brain axis interaction. This approach provides a simple and promising strategy for inflammation-targeted delivery of probiotics to the intestine and shows great potential for UC therapy and associated cognitive disorders.

Bioactive chitosan-BSA Maillard-derived chrysin-loaded nanoparticles: A gastroprotective, biomucoadhesive approach for enhanced oral therapy in ulcerative colitis

The current limitations of oral nanomedicines such as aminosalicylates, immunosuppressants, corticosteroids, and antibiotics include the toxic byproducts from nanocarrier synthesis, poor targeting and retention within the inflamed colon, delayed release at inflammation sites, susceptibility to gastric degradation, reduced efficacy under hypoxic conditions, MUC2 homeostasis disruption, and insufficiently addressing the disease's root causes. This research presents an innovative approach of using non-toxic, biodegradable, and biocompatible Maillard reaction-based nanoparticles (MPs) for targeted oral drug delivery in IBD therapy. Through the development of mucoadhevise chitosan-bovine serum albumin Maillard nanoparticles shielded with biocompatible, non-toxic, non-immunogenic, gastroprotective pectin (P@CMPs) encapsulating with chrysin, a flavonoid with anti-inflammatory and hyperoxia properties whose bioavailability is negatively affected by gastric degradation. P@CMPs had a spherical, uniform 300 nm hydrodynamic diameter, confirmed by TEM and FESEM. Chrysin encapsulation efficiency and loading capacity were ∼96 % and 16 %, respectively, demonstrating effective nanoparticle formulation The P@CMPs is designed to withstand the gastrointestinal environment, ensuring targeted delivery and prolonged retention in inflamed colonic regions. In a dextran sodium sulfate-induced colitis mouse model, P@CMPs markedly mitigated inflammation, suppressed proinflammatory cytokine levels, and augmented the expression of MUC2, a crucial factor for maintaining the integrity of the gut barrier. By employing non-toxic, biocompatible and biodegradable materials, our P@CMPs approach offers a promising avenue for advancing IBD treatment, addressing various challenges and precise oral delivery within the gastrointestinal system.

Common mechanisms of Gut microbe-based strategies for the treatment of intestine-related diseases: based on multi-target interactions with the intestinal barrier

The concurrent occurrence and exacerbation of multiple diseases, including geriatric diseases and chronic diseases, impose a heavy burden on human health and medical expenses. Clarifying the common mechanisms of related multifarious diseases and developing preventive and therapeutic strategies with synergistic effects for multiple diseases are of great significance in alleviating the burden on the medical system and reducing patients' burden of drug metabolism. Recent studies have revealed that gut microbiota disorders and intestinal barrier damage, which consequently cause metabolic and immunological disorders, may be a common pathological basis underlying various intestinal-related diseases. In this review, we focus on the intestinal barrier function, summarizing the multi-target interactions and common mechanisms involved in diseases related to the gut such as ulcerative colitis, colorectal cancer, and type 2 diabetes. We identified gut microbe-based strategies, including probiotics, prebiotics, synbiotics, postbiotics, as well as potential targets in faecal microbiota transplant and berberine. The common mechanisms and key targets in the treatment of these diseases mainly include increasing the abundance of beneficial genera Bifidobacterium and Lactobacillus, increasing the levels of Short Chain Fatty Acids, restoring the intestinal mechanical barrier, and suppressing gut inflammation infiltration. We aim to provide a crucial basis and direction for the development of novel drugs with therapeutic effects for multiple diseases, thereby alleviating the patients' burden of medication and enhancing the efficacy of treatment.

Oral delivery of tunable oxidation-responsive budesonide-loaded nanoparticles enhances inflammation modulation in intestinal colitis

The rising global prevalence and socio-economic impact of Inflammatory Bowel Disease (IBD) highlight the pressing demand of innovative solutions. Drug-targeting technologies are urgently needed to effectively deliver drugs directly to the affected areas of the gastrointestinal tract (GIT). In this work, a surface-tunable nanosystem responsive to reactive oxygen species (ROS) was developed for the focal oral delivery of budesonide to IBD affected GIT areas. Poly(lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) were functionalized with a dense hydrophilic polyethylene glycol (PEG) corona linked by a ROS-sensitive moiety to obtain cleavable PEG (CleavPEG) NPs. CleavPEG NPs with nearly 100 nm and high association efficiency (∼70 %) presented an oxidation-responsive in vitro release of budesonide highly associated (> 60 %) with epithelial intestinal cells and macrophages without decreasing cell metabolic activity. In an inflamed 3D intestinal model, budesonide association to NPs allowed for minimal permeation of budesonide, when compared to its free form, with a similar reduction of IL-8, CXCL10/IP-10 and CCL20/MIP3a. Moreover, in a DSS-induced colitis mice model, CleavPEG NPs accumulated more in the colon than PEG NPs without cleavable linker, and repeated oral treatment with budesonide-loaded CleavPEG NPs decreased intestinal inflammation: confirmed by colonoscopy and quantified by a disease activity index (DAI) and levels of pro-inflammatory cytokines in colon comparable to healthy animals. CleavPEG NPs were efficiently responsive to oxidative environment, and improved budesonide efficacy in resolving inflammation, showing promise for the treatment of IBD.

Chiral Zinc Sulfide Nanoparticles Scavenging Reactive Oxygen Species for Remodeling Intestinal Homeostasis

Elevated levels of reactive oxygen species (ROS) and gut microbiota dysbiosis are crucial factors that exacerbate inflammatory bowel disease (IBD). To address this, we successfully synthesized zinc sulfide nanoparticles (ZnS NPs) with a particle size of approximately 500 nm and a maximum g-factor of 0.07, utilizing l-/d-cysteine as chiral ligands. Chirality gives NPs unique bioactivity. These chiral ZnS NPs could enter macrophages through the CD44 and clathrin pathways, which enhanced the ability to scavenge ROS, in turn significantly inhibited the NF-κB and NLRP3 signaling pathways, thereby reducing the secretion of TNF-α, IL-6, and IL-1β, while upregulating IL-10. In vivo experimental data showed that l-ZnS NPs outperformed 5-aminosalicylic acid, significantly improving body weight, reducing the IBD activity index, and attenuating tissue damage. Concurrently, l-ZnS NPs exhibited a marked prophylactic effect. The benchmark studies verified that l-ZnS NPs increased the abundance of the beneficial Lachnospiraceae NK4A136 by 10.55-fold and decreased harmful Enterobacter by 2914.00-fold, thereby reshaping the intestinal microecological balance. Pharmacokinetic and biosafety assessments confirmed the safety of l-ZnS NPs. Our findings indicate that chiral ZnS NPs hold great potential as nanodrugs for the treatment and prevention of IBD, providing an important foundation for the development of IBD therapeutic strategies.

Sodium butyrate alleviates colitis by inhibiting mitochondrial ROS mediated macrophage pyroptosis

Inflammatory bowel disease (IBD) is a chronic inflammatory bowel disease with unclear causes and limited treatment options. Sodium butyrate (NaB), a byproduct of dietary fiber in the intestine, has demonstrated efficacy in treating inflammation. However, the precise anti-inflammatory mechanisms of NaB in colon inflammation remain largely unexplored. This study aims to investigate the effects of NaB on dextran sulfate sodium (DSS)-induced colitis in rats. The findings indicate that oral administration of NaB effectively prevent colitis and reduce levels of serum or colon inflammatory factors. Additionally, NaB demonstrated in vitro inhibition of RAW264.7 inflammation cytokines induced by LPS, along with suppression of the ERK and NF-κB signaling pathway activation. Moreover, NaB mitigated LPS and Nigericin-induced RAW264.7 pyroptosis by reducing indicators of mitochondrial damage, including increased mitochondrial membrane potential (JC-1) levels and decreased Mito-ROS production. NaB increases ZO-1 and Occludin expression in CaCo2 cells by inhibiting RAW264.7 pyroptosis. These results suggest that NaB could be utilized as a therapeutic agent or dietary supplement to alleviate colitis.

Comparative efficacy of preventive vs. therapeutic resveratrol in modulating gut microbiota and alleviating inflammation in DSS-induced colitis

BACKGROUND

Inflammatory bowel disease (IBD) management remains challenging due to limited preventive strategies and the low bioavailability of therapeutic agents like resveratrol (RSV). While RSV exhibits anti-inflammatory properties, its preventive potential via gut microbiome modulation remains unexplored.

METHODS

A murine colitis model was established using 2.5% DSS, with mice randomized into control (CON), DSS, therapeutic RSV treatment (RSV), and preventive RSV treatment (PRE) groups. Clinical outcomes, intestinal barrier integrity, inflammatory cytokines, macrophage polarization, TLR4/NF-κB signaling, and gut microbiota (16S rRNA sequencing) were systematically evaluated.

RESULTS

Preventive RSV (PRE) outperformed therapeutic RSV across all metrics. PRE attenuated colitis severity by 51.4% (weight loss, P < 0.001 vs. RSV) and restored mucosal architecture (P = 0.048 vs. DSS). Mechanistically, PRE normalized barrier function via transcriptional (ZO-1: 56.7% of CON; Occludin: 14-fold induction vs. DSS) and protein-level recovery (ZO-1: 96.5% of CON, P = 0.02), suppressed pro-inflammatory cytokines (TNF-α: 80.8%; IL-6: 69.9%; IL-18: >96%, P < 0.001 vs. DSS), and promoted M2 macrophage polarization (CD206: 1.7-fold vs. CON, P = 0.02) through TLR4/NF-κB inhibition (53% TLR4 reduction vs. 15% with RSV, P < 0.001). Despite comparable α-diversity between RSV and PRE, PRE uniquely enriched barrier-protective taxa (Lactococcus, Muribaculum) and restored microbial amino acid biosynthesis. Crucially, PRE's efficacy despite low systemic bioavailability implicated microbiome-mediated "luminal priming" as its primary mechanism.

CONCLUSIONS

This study redefines preventive RSV as a microbial ecosystem engineer that preemptively fortifies the gut against inflammation via microbiome-immune-metabolic crosstalk. By prioritizing ecological prevention over symptom suppression, our findings offer a transformative "food as medicine" strategy for IBD, highlighting RSV's potential as a chronotherapeutic agent to reshape clinical paradigms.

Flos lonicerae polysaccharide alleviates inflammatory bowel disease by improving intestinal microbiota and inhibiting oxidative stress and the NF-κB pathway

Inflammatory bowel disease (IBD) is a chronic disease that is increasingly being recognized globally. IBD is difficult to cure and is in urgent need of more treatment options. Flos lonicerae polysaccharide (FLP) is an effective component extracted from traditional Chinese medicine flos lonicerae, and previous studies have demonstrated its therapeutic potential in treating inflammatory diseases such as rhinitis and dermatitis, but there has been few in-depth research on their regulation of IBD repair mechanisms. This study focuses on the regulatory mechanisms of FLP on the structure of the gut microbiome and immune homeostasis. Results have demonstrated that treatment with FLP effectively attenuates weight loss, reduces the release of proinflammatory cytokines, and restores spleen and colon structures in mice. These effects are achieved through modifying the intestinal microbial community structure, increasing beneficial bacteria, and decreasing harmful bacteria. Furthermore, FLP significantly impacts the levels of Coenzyme Q2, a lipid closely associated with mitochondrial function. This modulation possibly regulates oxidative stress levels and the NF-κB pathway, thereby contributing to the alleviation of IBD. Therefore, FLP as a natural product with multiple biological activities, exhibits potential therapeutic effects in regulating intestinal microbiota, reducing oxidative stress, and inhibiting the NF-κB pathway, suggesting it may serve as a novel strategy for IBD treatment.

Role of Pyroptosis in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a serious chronic condition marked by persistent and recurrent intestinal ulcers. Although the exact cause of IBD remains unclear, it is generally accepted that a complex interaction among dietary factors, gut microbiota, and immune responses in genetically predisposed individuals contributes to its development. Pyroptosis, an inflammatory form of programmed cell death activated by inflammasomes, is marked by the rupture of cell membranes and the subsequent release of inflammatory mediators. Emerging evidence indicates that pyroptosis plays a crucial role in the pathogenesis of IBD. Moderate pyroptosis activation can enhance intestinal immune defenses, while excessive inflammasome activation can trigger an inflammatory cascade, resulting in increased damage to intestinal tissues. This article reviews the molecular mechanisms underlying pyroptosis and highlights its role in the onset and progression of IBD. Furthermore, We explore recent advancements in IBD treatment, focusing on small molecule compounds that specifically target and inhibit pyroptosis.

Faecalibacterium Prausnitzii extracellular vesicles regulating macrophage differentiation via homologous recombination repair in colitis model

Inflammatory Bowel Disease (IBD) is characterized by chronic inflammation influenced by the depletion of beneficial gut microbiota, a critical factor in disease onset and progression. This study investigates the therapeutic potential of extracellular vesicles (EVs) derived from Faecalibacterium prausnitzii (F.p EVs), a commensal bacterium whose reduction is linked to IBD. Our research demonstrates that F.p EVs are preferentially taken up by macrophages, where they exert their anti-inflammatory effects through the enhancement of homologous recombination (HR) repair mechanisms. Specifically, F.p EVs upregulate the expression of key proteins involved in HR repair, such as BRCA1 and BRCA2, thereby reducing DNA damage and inhibiting the cGAS-STING pathway, which is central to the inflammatory response. This modulation of macrophage function results in decreased pro-inflammatory cytokine production and enhanced intestinal barrier integrity. By elucidating these mechanisms, our study provides a clear understanding of how F.p EVs can be used to target fundamental aspects of IBD pathology, laying the groundwork for the development of more effective and targeted therapies.

Beta-Sitosterol-Conjugated Sinapic Acid-Engineered Nanoliposome: Biomucoadhesive and Enzyme-Responsive Targeted Oral Therapy in Ulcerative Colitis

Developing oral drug delivery systems is promising for ulcerative colitis (UC). However, the key challenges, including formulation degradation under harsh gastric conditions, poor targeting efficiency, and limited colonic residence, lead to poor therapeutic efficacy that still needs to be tackled. Effective treatment requires a safe, efficacious, enzyme- and pH-responsive, biomucoadhesive oral drug delivery system to overcome these challenges. Therefore, we have developed chitosan-armored 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) nanoliposomes amalgamated with synthesized beta-sitosterol-sinapic acid (Be-S) conjugate, further encapsulated with 3,4-methylenedioxy-β-nitrostyrene (MNS) as NLRP3 inhibitor, termed C@MN@DMBe-S, to overcome the limitation of free MNS and sinapic acid. Formulated by the thin-film hydration method and processed through extrusion, these unilamellar liposomes demonstrated structural stability and mucoadhesive properties due to chitosan coating. This configuration protected the nanoliposomes from the gastric acidic environment and allowed retention in the inflamed colon for 48 h. The enzyme-responsive C@MN@DMBe-S nanoliposome releases sinapic acid at the inflamed colonic site via esterase activity, providing sustained and controlled release of MNS. This synergistic action delivers antioxidant and anti-inflammatory effects while influencing the gut microbiota composition by releasing short-chain fatty acids. Moreover, therapeutic investigations revealed that C@MN@DMBe-S exhibited superior efficacy compared with free MNS when administered orally. The formulation effectively downregulated NF-κB, NLRP3, Caspase-1, and IL-1β expression while upregulating MUC5AC expression, indicating enhanced anti-inflammatory and protective effects and thereby promoting mucosal healing. In addition, C@MN@DMBe-S was found to regulate immune cell expression and effectively downregulate neutrophil infiltration. This armor- and enzyme-responsive strategy elucidates the impact of oral nanomedicines on mitigating UC and is demonstrated as an effective treatment.

Unveiling the Cuproptosis in Colitis and Colitis-Related Carcinogenesis: A Multifaceted Player and Immune Moderator

Cuproptosis represents a novel mechanism of cellular demise characterized by the intracellular buildup of copper ions. Unlike other cell death mechanisms, its distinct process has drawn considerable interest for its promising applications in managing inflammatory bowel disease (IBD) and colorectal cancer (CRC). Emerging evidence indicates that copper metabolism and cuproptosis may exert dual regulatory effects within pathological cellular environments, specifically modulating oxidative stress responses, metabolic reprogramming, and immunotherapeutic efficacy. An appropriate level of copper may promote disease progression and exert synergistic effects, but exceeding a certain threshold, copper can inhibit disease development by inducing cuproptosis in pathological cells. This makes abnormal copper levels a potential new therapeutic target for IBD and CRC. This review emphasizes the dual function of copper metabolism and cuproptosis in the progression of IBD and CRC, while also exploring the potential application of copper-based therapies in disease treatment. The analysis further delineates the modulatory influence of tumor immune microenvironment on cuproptosis dynamics, while establishing the therapeutic potential of cuproptosis-targeted strategies in circumventing resistance to both conventional chemotherapeutic agents and emerging immunotherapies. This provides new research directions for the development of future cuproptosis inducers. Finally, this article discusses the latest advances in potential molecular targets of cuproptosis and their related genes in the treatment of IBD and CRC, highlighting future research priorities and unresolved issues.

Macrophage-augmented intestinal organoids model virus-host interactions in enteric viral diseases and facilitate therapeutic development

The pathogenesis of enteric viral infections is attributed to both viral replication and the resultant immune-inflammatory response. To recapitulate this complex pathophysiology, we engineer macrophage-augmented organoids (MaugOs) by integrating human macrophages into primary intestinal organoids. Echovirus 1, echovirus 6, rotavirus, seasonal coronavirus OC43 and SARS-CoV-2- known to directly invade the intestine- are used as disease modalities. We demonstrate that these viruses efficiently propagate in MaugOs and stimulate the host antiviral response. However, rotavirus, coronavirus OC43 and SARS-CoV-2, but not the two echoviruses, trigger inflammatory responses. Acetate, a microbial metabolite abundantly present in the intestine, potently inhibits virus-induced inflammatory responses in MaugOs, while differentially affecting viral replication in macrophages and organoids. Furthermore, we provide a proof-of-concept of combining antiviral agent with either anti-inflammatory regimen or acetate to simultaneously inhibit viral infection and inflammatory response in MaugOs. Collectively, these findings demonstrate that MaugOs are innovative tools for studying the complex virus-host interactions and advancing therapeutic development.

"Remodeling the intestinal immune microenvironment": immune regulation and tissue regeneration by mesenchymal stem/stromal cells in the repair microenvironment of inflammatory bowel disease

The global prevalence of inflammatory bowel disease (IBD) has significantly increased in recent decades. IBD is a long-term, recurring, gastrointestinal inflammatory condition that mainly comprises two primary clinical types: ulcerative colitis and Crohn's disease. The current treatment paradigm for IBD primarily focuses on symptom management. However, this approach does not support mucosal epithelial repair, maintenance of barrier homeostasis, or regulation of biological functions in the gut. Conventional therapies rely on the frequent use of high-dose medications, including antibiotics, nonsteroidal anti-inflammatory drugs, biological agents, and immunomodulators. Recently, mesenchymal stem/stromal cells (MSCs) have gained interest in tissue regeneration owing to their unique ability to differentiate and secrete regulatory factors, including extracellular vesicles (EVs), which play crucial roles in abnormal organization. Various routes of administration have been explored in preclinical and clinical studies to deliver MSCs from diverse tissue sources. The routes include intraperitoneal, intravenous, and local (intracolonic or rectal) delivery. The MSCs employed were obtained from various tissues, including bone marrow, umbilical cord, and adipose tissue. This article reviews the research framework for the application of MSCs and EVs secretion in the treatment of IBD, emphasizing key immunological effects, such as immune microenvironment regulation, intestinal barrier stabilization, and therapeutic approaches targeting intestinal barrier disorders. The discussion primarily focuses on the advantages of MSCs over other biologics, impairment of gut mucosal tissue-resident mesenchymal stem cells in IBD development, immune targets (at the cellular and molecular levels) within the framework of IBD, and the reparative effects of MSCs in the microenvironment of IBD. We aimed to present an overview of the current trends in MSC research and therapy, as well as to identify the challenges and future directions that must be addressed to advance research on MSC-mediated therapeutic strategies for IBD.

ERMAP attenuates DSS-induced colitis in mice by regulating macrophage and T cell functions

BACKGROUND & AIMS

Both macrophages and T cells play a critical role in inflammatory bowel disease (IBD) development. Since our previous studies have shown that a novel immune checkpoint molecule erythrocyte membrane-associated protein (ERMAP) affects macrophage polarization and negatively regulates T cell responses, we investigated the effects of ERMAP on DSS-induced colitis progression in mice.

METHODS

C57BL/6 mice developed a dextran sodium sulfate (DSS) colitis model, treated with control Fc protein (Control Ig) and ERMAP-Fc fusion protein (ERMAP-Ig) for 12 days to assess colitis severity by disease activity index (DAI), weight loss, colon length, histology, flow cytometry, Q-PCR, WB, ELISA, and the effect of adoptive transfer of ERMAP knockout mice (ERMAP-/-) peritoneal macrophages on DSS colitis mice. In vitro, the effects of the RAW264.7 macrophage cell line that interfered with ERMAP expression on macrophage polarization and T cells were analyzed by flow cytometry.

RESULTS

We show here that administration of ERMAP protein significantly increases the proportion of anti-inflammatory M2-type macrophages and inhibits T cell activation and proliferation in DSS-induced colitis mice. Knockdown of ERMAP in RAW264.7 macrophages reduces M2-type macrophage polarization and increases T cell responses. Adoptive transfer of macrophages from ERMAP-/- exacerbates DSS-induced colitis. Global gene expression analysis by RNA-seq shows that ERMAP inhibits the NOD-like receptor (NLR) protein family pathway in macrophages.

CONCLUSIONS

In summary, our results suggest that administration of ERMAP can protect DSS-induced colitis in mice by regulating T cell and macrophage functions. This study adds to the evidence for various mechanistic pathways associated to the pathogenesis of IBD, which could subsequently be translated to novel therapeutics.

Human umbilical cord mesenchymal stem cell-derived exosomes repair IBD by activating the SIRT1-FXR pathway in macrophages

BACKGROUND

Inflammatory bowel disease (IBD), a chronic immune disorder, has increasing global incidence and poor treatment outcome. Abnormal macrophage function is implicated in the pathophysiology of IBD. In this study, we investigated the mechanism by which human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Ex) inhibit inflammation in IBD mouse and macrophage inflammation models.

METHODS

We established a dextran sodium sulfate (DSS)-induce BALB/c mice model of IBD and treated with hucMSC-Ex via tail vein to evaluate their repair effect on IBD mice. An in vitro macrophage inflammation model was established using lipopolysaccharide (LPS) and Nigericin (Nig) by stimulating mouse macrophage RAW264.7 and human myeloid leukemia mononuclear (THP-1) cells to assess the repair effect of hucMSC-Ex on macrophage inflammation. EX 527, an effective inhibitor of silent information regulator of transcription 1 (SIRT1), was employed in both the in vivo and in vitro models to explore the effect of hucMSC-Ex on the SIRT1-FXR (farnesoid X receptor) pathway in macrophages during the attenuation of inflammation.

RESULTS

HucMSC-Ex effectively inhibited inflammation in both the in vivo and in vitro models by up-regulating the expressions of SIRT1 and FXR, which reduced the acetylation level of FXR and inhibited the activation of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome. The addition of EX 527 further proved that hucMSC-Ex can reduce the acetylation of FXR by activating the SIRT1-FXR pathway, and the decrease of FXR acetylation was directly related to the inhibition of the activity of the NLRP3 inflammasome.

CONCLUSION

HucMSC-Ex alleviates IBD by reducing the acetylation level of FXR through activating the SIRT1-FXR pathway in macrophages and directly negatively regulating the activation of NLRP3 inflammasomes, thus inhibiting the occurrence of the inflammatory process.

Pro-inflammatory macrophages contribute to developing comorbid anxiety-like behaviors through gastrointestinal vagal afferent signaling in experimental colitis mice

Anxiety symptoms are commonly observed in individuals with inflammatory bowel disease (IBD), but the mechanistic link between IBD and comorbid anxiety remains incompletely understood. Our previous study revealed that vagal gut-brain signaling contributes to driving comorbid anxiety-like behaviors in dextran sulfate sodium (DSS)-induced colitis mice, but how vagus nerve senses and transmits information to the brain in response to changes in the colonic microenvironment following DSS treatment remain elusive. Here, we identify a critical contribution of pro-inflammatory CD86+ macrophages to activate gut-innervating vagal afferents and ultimately drive anxiety-like behaviors in DSS-treated mice. An increased number of F4/80+ macrophages accumulated closely with gut-innervating vagal afferent fibers following DSS treatment. Depletion of macrophages alleviated DSS-induced anxiety-like behaviors, whereas peripheral delivery of lipopolysaccharide-activated M1 macrophages promoted anxiety-like behaviors, which were prevented by bilateral vagal afferent ablation. Moreover, differential expression levels of anxiety-like behaviors were positively correlated with neuronal activity changes in the nucleus tractus solitarius, locus coeruleus, and basolateral amygdala. Finally, treatment with either anti-α4β7 integrin antagonist vedolizumab or neutralizing anti-interleukin-1β monoclonal antibody effectively alleviated DSS-induced anxiety-like behaviors. Collectively, these findings unravel a mechanism of macrophage-to-vagus nerve communication via cytokine signaling responsible for comorbid anxiety associated with experimental colitis and suggest that pro-inflammatory CD86+ macrophages may represent a potential therapeutic target for psychological comorbidities in patients with IBD.

Macrophage and mitochondrion dual-targeting astaxanthin nanoparticles prepared by Maillard reaction for colonic inflammation alleviation

This study demonstrated the design of whey protein isolate (WPI)-mannose (Man) conjugates with triphenylphosphonium bromide (TPP) through self-assembly to prepare macrophage and mitochondrion dual-targeting astaxanthin (AXT) nanoparticles (AXT@TPP-WPI-Man). The nanoparticles displayed spherical structures with a well-dispersed size of approximately 206.1 ± 39.2 nm, with good biocompatibility, stability, and targeting capabilities. In vitro experiments demonstrated the specific accumulation of AXT@TPP-WPI-Man in mitochondria and exhibited good targeting ability toward macrophages. The AXT@TPP-WPI-Man effectively reduced reactive oxygen species and preserved the normal mitochondrial membrane potential. The AXT@TPP-WPI-Man treated ulcerative colitis mice exhibited a 52.32% increase in colon length with significant improvement in weight loss, disease activity index scores, and reduced release of inflammatory cytokines. Immunofluorescence staining indicated AXT@TPP-WPI-Man alleviated ulcerative colitis by reducing M1 polarization in colonic macrophages while promoting M2 polarization. The dual-targeting AXT@TPP-WPI-Man has the potential to improve astaxanthin bioavailability, presenting a promising delivery method for the treatment of ulcerative colitis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-024-00255-9.

Orally Administered Functional Polyphenol-Nanozyme-Armored Probiotics for Enhanced Amelioration of Intestinal Inflammation and Microbiota Dysbiosis

Maintaining microbiota balance and enhancing the antioxidant performance of nanozyme-based probiotic systems are crucial for effective inflammatory bowel disease (IBD) therapy. Despite significant advancements, developing a green and safe coating technology that functionalizes probiotics with nanozymes while preserving the activity of both components remains a challenge. To address this, chitosan-modified epigallocatechin gallate (EGCG-CS, EC)is synthesized, leveraging the intrinsic adhesive and coordination properties of polyphenols to capture gold nanozymes (AuNPs), forming ECA complexes that enhance nanozyme activity. When coated onto Escherichia coli Nissle 1917 (EcN), the resulting ECA@EcN system effectively scavenged reactive oxygen species (ROS), improving probiotic viability and promoting colon accumulation. Mechanistically, ECA protected EcN by suppressing the activation of the Flagellar Assembly and Branched-Chain Amino Acid Synthesis pathways, ultimately alleviating inflammation and modulating intestinal microbial communities to relieve IBD symptoms. Given the biocompatibility of its components and the environmentally friendly assembly approach, this polyphenol-nanozyme-armored probiotic system represents a promising platform for IBD treatment.

Tetrahedral Framework Nucleic Acid Relieves Sepsis-Induced Intestinal Injury by Regulating M2 Macrophages

This study aimed to clarify the role and mechanism of tetrahedral framework nucleic acids (tFNAs) in regulating M2 macrophages to reduce intestinal injury. An intestinal injury model was established by intraperitoneal injection of lipopolysaccharides (LPS) in mice to explore the alleviating effects of tFNAs on intestinal injury. Inflammatory factors were detected by quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA). The intestinal barrier and permeability were assessed using western blotting and immunohistochemistry. Macrophages in the gut were localised and quantified using immunofluorescence. Western blotting was used to investigate the role and mechanism of tFNAs in regulating macrophages and alleviating inflammation in the injured intestines. These results show that tFNAs attenuated sepsis-induced intestinal injury. tFNAs can also promote the intestinal barrier reconstruction and reduce intestinal permeability. In vivo, tFNAs accelerated the aggregation of M2 macrophages at an early stage of injury and reduced the number of M1 macrophages in the intestine. In addition, tFNAs enhanced the clearance ability of intestinal macrophages. They activated the signalling and transcription activating factor 1(STAT1) and cytokine signalling inhibitory factor 1/3 (SOCS1/3) pathways by increasing the expression of the phagocytic receptor Mertk. These findings indicated that tFNAs can alleviate sepsis-induced intestinal injury by regulating M2 macrophages, providing a new option for treating intestinal injury.

CO-Releasing Polyoxometalates Nanozyme with Gut Mucosal Immunity and Microbiota Homeostasis Remodeling Effects for Restoring Intestinal Barrier Integrity

Disruption of the intestinal epithelial barrier, driven by imbalances in gut mucosal immunity and microbial homeostasis, is central to the onset and progression of inflammatory bowel disease (IBD). This study introduces a CO-releasing polyoxometalates (POMs) nanozyme (PMC), synthesized by coordinating pentacarbonyl manganese bromide with molybdenum-based POM nanoclusters. PMC demonstrates targeted accumulation at IBD-affected sites, efficient scavenging of reactive oxygen species (ROS), and responsive CO release, resulting in multiple therapeutic effects. Extensive in vitro and in vivo studies have validated the exceptional capacity of PMC to repair intestinal barrier, attributed to their potent antioxidant and anti-inflammatory properties, thereby achieving significant therapeutic efficacy in ulcerative colitis treatment. 16S rRNA sequencing indicated that PMC efficiently remodeled the gut microbiota composition. Single-cell RNA sequencing indicates a reduction in pro-inflammatory M1 macrophages, alongside suppressed ROS and inflammatory signaling pathways. Concurrently, an increase in reparative M2 macrophages and intestinal stem cells is observed, in addition to significant activation of the VEGF signaling pathway in macrophages and the NOTCH pathway in stem cells, underscoring the potential of PMC to restore immune balance and promote tissue repair. This study positions PMC as a promising, multifunctional therapeutic agent for IBD treatment owing to its robust intestinal barrier-restoring capability.

Potential therapeutic strategies targeting efferocytosis for inflammation resolution and tissue repair in inflammatory bowel disease

Efferocytosis, the process by which apoptotic cells (ACs) are recognized and cleared by phagocytes, is a critical mechanism in maintaining intestinal immune homeostasis and promoting the resolution of inflammation. Inflammatory bowel disease (IBD), encompassing Crohn's disease (CD) and ulcerative colitis (UC), is characterized by chronic intestinal inflammation, wherein defective efferocytosis contributes to the accumulation of ACs, secondary necrosis, and sustained mucosal damage. This review delineates the molecular mechanisms underlying efferocytosis and systematically examines its functional roles across five key intestinal phagocytic cell types: macrophages, dendritic cells (DCs), neutrophils, intestinal epithelial cells (IECs), and Paneth cells (PCs). Particular emphasis is placed on the dysregulation of efferocytosis capacity in IBD pathogenesis and the consequences of impaired apoptotic cell clearance in both professional and non-professional phagocytes. Furthermore, we evaluate emerging therapeutic strategies designed to restore or enhance efferocytosis, including modulation of macrophage polarization, LC3-associated phagocytosis pathways, nanotechnology-enabled delivery systems, and stem cell-based interventions. A comprehensive understanding of cell-type-specific efferocytosis in the intestinal microenvironment offers promising directions for the development of targeted, inflammation-resolving therapies for IBD.

IDO1 induced macrophage M1 polarization via ER stress-associated GRP78-XBP1 pathway to promote ulcerative colitis progression

Ulcerative colitis (UC) is a chronic inflammatory bowel disorder distinguished by alternating phases of remission and exacerbation. Restoring immune balance through the modulation of M1 macrophage polarization represents a potentially valuable therapeutic strategy for UC. Indoleamine 2,3-dioxygenase-1 (IDO1) has been shown to contribute to macrophage plasticity, but its role in the pathogenesis of UC via regulating M1 macrophage polarization has not been studied yet. For the clinical component, we analyzed IDO1 expression in UC using bioinformatics analysis of Gene Expression Omnibus (GEO) datasets and validated the result using western blotting of colonic tissues from new recruited UC patients. Colitis was induced in mice via dextran sulfate sodium (DSS) treatment and subsequently treated with oral administration of 1-methyl-DL-tryptophan (1-MT), an inhibitor of IDO1 pathway. The results indicated that IDO1 expression was significantly elevated in UC patients and correlated with M1 macrophage polarization observed in both human data and colitis mice. Furthermore, 1-MT markedly ameliorated DSS-induced weight loss, colonic shortening and disease severity via inhibiting IDO1 expression level, downregulating GRP78-XBP1 pathway and reducing M1 proportion. Notably, in vitro study revealed that overexpressing IDO1 in RAW264.7 cells induced macrophage M1 polarization with increased expression levels of GRP78 and XBP1, which was attenuated by 1-MT treatment. Additionally, the catalytic effect exerted by IDO1 overexpression on M1 polarization was neutralized by employing an inhibitor targeting the endoplasmic reticulum (ER) stress pathway. Thus, our findings suggest that IDO1 may promote UC progression by skewing macrophages towards M1 polarization through ER stress-associated GRP78-XBP1 pathway.

Stimuli-Responsive Nanomedicines for the Treatment of Non-cancer Related Inflammatory Diseases

Nanomedicines offer a means to overcome the limitations associated with traditional drug dosage formulations by affording drug protection, enhanced drug bioavailability, and targeted drug delivery to affected sites. Inflamed tissues possess unique microenvironmental characteristics (including excessive reactive oxygen species, low pH levels, and hypoxia) that stimuli-responsive nanoparticles can employ as triggers to support on-demand delivery, enhanced accumulation, controlled release, and activation of anti-inflammatory drugs. Stimuli-responsive nanomedicines respond to physicochemical and pathological factors associated with diseased tissues to improve the specificity of drug delivery, overcome multidrug resistance, ensure accurate diagnosis and precision therapy, and control drug release to improve efficacy and safety. Current stimuli-responsive nanoparticles react to intracellular/microenvironmental stimuli such as pH, redox, hypoxia, or specific enzymes and exogenous stimuli such as temperature, magnetic fields, light, and ultrasound via bioresponsive moieties. This review summarizes the general strategies employed to produce stimuli-responsive nanoparticles tailored for inflammatory diseases and all recent advances, reports their applications in drug delivery, and illustrates the progress made toward clinical translation.

A Sequential Release Micro-nano System for Colitis Therapy via Gut Microbiota and Immune Regulation

Commencing with the breakdown of the intestinal barrier, various pathogenic factors, such as dysbiosis of the gut microbiota, harmful inflammatory cytokines, and immune system imbalance, collectively contribute to the development of colitis. Numerous interventions focusing on single factors have been developed to provide short-term therapeutic benefits, but the continued existence of unresolved pathogenic factors can lead to disease exacerbation. Here we have designed a multicomponent system-inulin microspheres encapsulating selenium-containing nanomicelles, aiming to tackle the multiple factors associated with colitis. This micro-nano drug delivery platform achieves sequential release of drugs in the inflamed colon, with each component of the system functioning independently and jointly. The outer layer of inulin supplies nutrients for probiotics. The inner core comprises selenocystamine and 3-oxolithocholic acid, which polarize macrophages towards an anti-inflammatory phenotype and regulate adaptive immunity by inhibiting TH17-cell differentiation, respectively. In an acute colitis mouse model, this therapeutic system ameliorates colonic inflammation, enhances the abundance of gut microbiota, and modulates the mucosal immune system, showing potential in preventing colitis.

Developmentally endothelial locus-1 facilitates intestinal inflammation resolution by suppressing the Cmpk2-cGAS-STING pathway and promoting reparatory macrophage transition

INTRODUCTION

Abnormalities in inflammation resolution function are intimately linked to chronic inflammation, and proresolution therapies may offer novel opportunities for IBD treatment. Developmental endothelial locus 1 (DEL-1), a natural modulator of tissue immunity and inflammation resolution, has not been studied in IBD.

OBJECTIVES

We aimed to investigate the expression and functions of DEL-1 in IBD.

METHODS

Assessment of DEL-1 expression in patients, murine models, and cellular levels. To explore the effects of DEL-1 in the acute and recovery phases of inflammation, overexpression plasmids, adeno-associated viruses for DEL-1 knockdown, and DEL-1-Fc fusion proteins were administered to cells and mice. Additionally, the potential mechanism of DEL-1 in IBD was demonstrated using flow cytometry, RNA-Seq, ChIP, dual-luciferase reporter assays and 16S rRNA.

RESULTS

DEL-1 levels were significantly reduced in IBD patients, colitis mice and macrophages, while the levels increased with inflammation to resolve. Transfection with DEL-1 overexpression plasmid or DEL-1-Fc intervention reduces levels of inflammatory cytokines in both phases and upregulates reparative gene levels in the recovery phase. DEL-1 knockdown inhibits inflammation resolution of colitis. Mechanistically, we demonstrated that DEL-1 inhibits Cmpk2-dependent mtDNA synthesis, thereby inhibiting the cGAS-STING pathway to ameliorate intestinal inflammation. Moreover, DEL-1 promotes reparative macrophage transition in the repair model of colitis. Spi1 was identified as a transcription factor that regulates Cmpk2 and the reparative gene Il10. Intervention with overexpression plasmid of Spi1 or Cmpk2 or the STING agonist DMXAA reverses the effects of DEL-1. In parallel, DEL-1 also inhibits neutrophil recruitment, repairs the intestinal barrier, and improves intestinal microbiota dysbiosis.

CONCLUSION

We report the first demonstration that DEL-1 significantly ameliorates colonic inflammation in colitis mice. Our findings elucidate a novel mechanism wherein DEL-1 exerts its protective effects by suppressing the Cmpk2-cGAS-STING pathway and promoting reparative macrophage transition. These results collectively position DEL-1 as a promising therapeutic avenue for IBD.

Dietary targeting of TRPM8 rewires macrophage immunometabolism reducing colitis severity

The interplay between diet, host genetics, microbiota, and immune system has a key role in the pathogenesis of inflammatory bowel disease (IBD). Although the causal pathophysiological mechanisms remain unknown, numerous dietary nutrients have been shown to regulate gut mucosal immune function, being effective in influencing innate or adaptive immunity. Here, we proved that transient receptor potential melastatin 8 (TRPM8), a non-selective cation channel, mediates LPS- evoked Ca2+ influx in macrophages leading to their activation. Additionally, we showed that TRPM8 is selectively blocked by the dietary flavonoid luteolin, which induced a pro-tolerogenic phenotype in pro-inflammatory macrophages. Accordingly, genetic deletion of Trpm8 in macrophages caused a deficit in the activation of pro-inflammatory metabolic and transcriptional reprogramming, leading to reduced production of key pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. The TRPM8 anti-inflammatory effect was found to be dependent on lactate which in turn induces IL-10 gene expression. Adoptive transfer of TRPM8-deficient bone marrow in wild-type mice improved intestinal inflammation in a model of colitis. Accordingly, oral administration of luteolin protected mice against colitis through an impairment in the innate immune response. Our study reveals the potential of targeting TRPM8 through specific nutrient interventions to regulate immune function in sub-clinical scenarios or to treat inflammatory diseases, primarily driven by chronic immune responses, such as IBD.

Relevance of mouse and human IBD patient-derived colon organoids to investigate intestinal macrophage differentiation

The gastrointestinal tract is a remarkable example of complex biology, with a constant dialogue between the intestinal epithelium, in close contact with the microbiota, and the immune cells that protect the gut from infection. Organoids have revolutionized our approach to modeling the intestinal cellular compartment and have opened new avenues for unraveling the mechanisms involved in intestinal homeostasis and chronic pathogenesis, such as inflammatory bowel disease. To date, few models have been established to explore the role of the colon, which is, however, the main site of inflammation in ulcerative colitis. Here, we used conditioned media produced by colon organoids from mice or humans (control patients and patients with ulcerative colitis) to investigate the relationship between macrophages and the colon epithelium. We addressed transcriptomic profiles of organoid conditioned media-stimulated bone marrow-derived macrophages and found that these cells exhibited a unique anti-inflammatory signature distinct from that of conventional in vitro IL-4/IL-13 M2-differentiated macrophages. In addition, organoid conditioned media induced a clear CD5 antigen-like-mediated immunoregulatory effect characterized by a significant reduction in lipopolysaccharide-induced inducible nitric oxide synthase expression. In line, organoid conditioned media from human colons inhibited lipopolysaccharide-dependent inflammatory cytokine expression in human monocyte-derived macrophages. Interestingly, the inflammatory marker CD68 was reduced by organoid conditioned media from control patients but not from patients with ulcerative colitis, suggesting epithelial dysfunction in patients with ulcerative colitis. Our results report new regulatory mechanisms in the colon and highlight the importance of developing new in vitro models to better characterize the relationship between the intestinal epithelium and immune mucosal cells.

Somatostatin and Mannooligosaccharide Modified Selenium Nanoparticles with Dual-Targeting for Ulcerative Colitis Treatment

Inflammatory bowel disease (IBD) is a prevalent condition worldwide, characterized by complex etiologies, limited efficacy of clinical drug treatments, and potential adverse effects. In this study, we designed 269 nm selenium nanoparticles with double-cell targeting for ulcerative colitis treatment. Somatostatin (SST) and mannooligosaccharide (MOS) were employed to functionalize an Eucommia ulmoides polysaccharide selenium nanoparticle (EUP-SeNP), resulting in the formulation of SST/MOS@EUP-SeNP. Nanoparticles were engineered to target intestinal epithelial cells and macrophages through specific cell surface receptors, enabling dual-targeted treatment. In addition, sodium alginate (SA) microspheres incorporating SST/MOS@EUP-SeNP were prepared for oral administration, protecting the nanoparticles from gastric fluid. The results showed that SA/SST/MOS@EUP-SeNP could preferentially target the inflamed colon tissue and adhere to the colon, enhance the intestinal barrier function, regulate the level of colon inflammation, enhance antioxidant capacity, and regulate the composition of intestinal microbes to effectively relieve the colitis induced by sodium glucan sulfate (DSS). Meanwhile, SA/SST/MOS@EUP-SeNP had excellent biocompatibility both in vivo and in vitro. To some extent, this study can provide a reference for the treatment of IBD.

MIF tautomerase inhibitor TE-11 prevents inflammatory macrophage activation and glycolytic reprogramming while reducing leukocyte migration and improving Crohn's disease-like colitis in male mice

Background & aims

Crohn's disease (CD) is a chronic inflammatory disorder primarily affecting the gastrointestinal tract. Leukocyte recruitment, M1 macrophage polarization and associated metabolic reprogramming are hallmarks of its pathomechanism. Here, we tested TE-11, a potent MIF tautomerase inhibitor (IC50 = 5.63 μmol/dm3) in experimental Crohn's disease in male mice, in leukocyte recruitment and in inflammatory M1 macrophage activation.

Methods

2,4,6-trinitrobenzenesulfonic acid-(TNBS)-induced colitis was utilized as a CD-model in male mice. We performed macroscopic scoring and cytokine measurements. We also analyzed MIF-induced leukocyte migration and evaluated apoptosis. LPS+IFN-γ-induced RAW264.7 cells were applied as a M1 macrophage model. We performed qPCR, ROS and nitrite determinations, ELISA measurements, mitochondrial oxygen consumption rate and extracellular acidification rate determinations.

Results

TE-11 improved mucosal damage, reduced inflammation score and concentration of IL-1β and IL-6 in the colon. It inhibited MIF-induced human blood eosinophil and neutrophil migration and counteracted the anti-apoptotic effect of MIF. In macrophages, MIF inhibition prevented M1 polarization by downregulating HIF-1α gene expression in LPS+IFN-γ-activated cells. Additionally, the molecule reduced mRNA transcription and protein expression of chemokine CCL-2 and cytokine IL-6 while further increasing SOD2 gene transcription and decreased ROS and nitrite production in macrophages. During inflammatory metabolic reprogramming, TE-11 prevented LPS+IFN-γ-induced metabolic shift from OXPHOS to glycolysis. Similarly to anti-inflammatory M2 cells, TE-11 improved mitochondrial energy production by increasing basal respiration, ATP production, coupling efficiency, maximal respiration and spare respiratory capacity.

Conclusion

Comprehensively, TE-11, a MIF tautomerase inhibitor ameliorates CD-like colitis, reduces MIF-induced eosinophil and neutrophil migration and prevents M1 polarization and associated metabolic reprogramming; therefore, it may prove beneficial as a potential drug candidate regarding CD therapy.

Lactobacillus acidophilus extracellular vesicles-coated UiO-66-NH2@siRNA nanoparticles for ulcerative colitis targeted gene therapy and gut microbiota modulation

Ulcerative colitis (UC) is a complex and chronic inflammatory bowel disease whose pathogenesis involves genetic and environmental factors, which poses a challenge for treatment. Here, we have designed an innovative integrated therapeutic strategy using Lactobacillus acidophilus extracellular vesicles (EVs) to encapsulate UiO-66-NH2 nanoparticles bounded with TNF-α siRNA (EVs@UiO-66-NH2@siRNA) for UC treatment. This system shows superior affinity to inflammation-related cells due to the Lactobacillus acidophilus EVs can maintain immune homeostasis by regulating the secretion of cytokines in vitro. siRNA can specifically target the key inflammatory TNF-α in UC and silence its gene expression, thereby regulating the process of inflammatory response. After oral administration, EVs@UiO-66-NH2@siRNA demonstrates an accurate delivery of TNF-α siRNA to colonize the colon site and exerts a siRNA therapeutic effect by inhibiting the expression of TNF-α, which alleviates the intestinal inflammation in DSS-induced UC model. Moreover, this system can modulate the types and compositional structures of gut microbiota and metabolites to achieve an anti-inflammatory phenotype, which is helpful for the repair of intestinal homeostasis. We also have proved that UiO-66-NH2 nanoparticles exhibit a high loading capacity for TNF-α siRNA and good pH responsiveness, improving the potent release of siRNA in colon tissue. Collectively, the EVs@UiO-66-NH2@siRNA nano-delivery system demonstrate a feasible combination therapeutic strategy for UC through gut microecology modulation, immune regulation and TNF-α siRNA silence, which may provide a potential targeted treatment approach for inflammatory bowel disease.

Probiotic Membrane-Modified Nanocomposite Alleviates Inflammation and Microbiota Dysbiosis in Colitis by Scavenging Oxidative Stress and Restoring Immune Homeostasis

Inflammatory bowel disease (IBD) is a complex chronic intestinal disorder in which excessive oxidative stress, dysregulated immune response, and microbiota dysbiosis contribute to recurrent episodes of inflammation in the colonic mucosa. Current clinical treatments focusing solely on inflammation resolution often exhibit limited efficacy due to the inability to fundamentally improve the pathological microenvironment. Herein, a probiotic membrane-modified drug delivery nanocomposite, namely, MPDA@Cur@EM, is developed for the comprehensive treatment of IBD. It contains two components: the curcumin-loaded mesoporous polydopamine nanoparticle (MPDA@Cur) as the core and the Escherichia coli Nissle 1917 outer membrane (EM) as the surface. For MPDA@Cur, the pathological microenvironment triggers the responsive release of curcumin. Importantly, MPDA@Cur can effectively alleviate the inflammatory response of LPS-activated macrophages through MPDA-mediated ROS scavenging and curcumin-induced M2 polarization. In the dextran sulfate sodium (DSS)-induced colitis model, the EM coating not only allows for the targeting enrichment of orally administered MPDA@Cur@EM to the inflamed colonic mucosa, but also participates in the regulation of intestinal flora. Consequently, MPDA@Cur@EM efficiently attenuates the inflammatory reaction and restores the intestinal barrier functions, demonstrated by the multipronged manner of restoring redox balance, remodeling immune homeostasis, and reshaping the gut microecology. Collectively, this work provides a safe and promising codelivery strategy of probiotic product, antioxidative nanoenzyme, and therapeutic drug for comprehensive management of IBD.

Effects of CB2 Receptor Modulation on Macrophage Polarization in Pediatric Inflammatory Bowel Disease

Macrophages play a crucial role in maintaining intestinal homeostasis and can exhibit either pro-inflammatory M1 or anti-inflammatory M2 phenotypes. The cannabinoid receptor type 2 (CB2) is involved in immune regulation and may represent a therapeutic target in inflammatory bowel disease (IBD). Our study investigates the phenotype of circulating macrophages and CB2 expression in children with IBD, assessing the role of CB2 stimulation in macrophage polarization, iron metabolism, and intestinal barrier function. Macrophages were isolated from 17 children with ulcerative colitis (UC), 21 with Crohn's disease (CD), and 12 healthy controls (CTR). Cells were treated with a CB2 agonist (JWH-133) and an inverse agonist (AM630). CB2 expression and macrophage polarization were assessed by Western blot. Iron metabolism was evaluated through IL-6, hepcidin levels, FPN-1 expression, and iron concentration. Inflammation was assessed by cytokine release. An in vitro "immunocompetent gut" model was used to study the effects of CB2 stimulation on macrophage polarization and intestinal barrier function. CB2 expression was reduced in IBD macrophages. Compared to controls, IBD patients showed increased M1 markers and pro-inflammatory cytokines, with a reduction in M2 markers and IL-13. Altered iron metabolism was observed, with increased [Fe3+], hepcidin release, and DMT1 expression, and reduced FPN-1. CB2 stimulation restored iron metabolism, induced M2 polarization, and improved intestinal barrier function. CB2 could represent a novel therapeutic target for IBD by modulating macrophage function, iron metabolism, and mucosal barrier restoration.

MHC class II+ macrophage differentiation is impaired in metastasized lungs via PGE2 receptor EP2

Monocytes differentiate into macrophages (Mφs) to facilitate lung metastasis, but the monocyte-to-Mφ transition during this process is not well understood. To investigate, we performed bulk RNA sequencing on Mφs isolated from the lungs of mice bearing Lewis lung carcinoma tumors and from naive lungs. Our results showed impaired differentiation of monocytes into major histocompatibility complex (MHC) class II+ Mφs, with an upregulation of PGE2-inducible genes, including Arg1, in tumor-associated Mφs (TAMs). In vitro experiments confirmed that prostaglandin E2 (PGE2) inhibits the differentiation of MHC class II+ Mφs while promoting Arg1+ Mφs via the E prostanoid 2 (EP2) receptor, accompanied by DNA methylation. Whole-genome bisulfite sequencing revealed that PGE2-EP2 signaling drives the hypermethylation and downregulation of gene sets related to myeloid cells in non-neoplastic tissues. Our study highlights PGE2-EP2-driven DNA methylation in the monocyte-to-TAM transition, suggesting potential therapeutic avenues for lung metastasis.

NAD+ modulation of intestinal macrophages renders anti-inflammatory functionality and ameliorates gut inflammation

Macrophages can maintain gut immune homeostasis by driving clearance of infection, but also can prevent chronic inflammation and induce tissue repair. Reduced nicotinamide adenine dinucleotide (NAD+) levels in macrophages have been reported to be associated with the onset of severe colitis. Given that dysregulation of gut macrophages plays a significant role in inflammatory bowel disease (IBD), they represent a potential target for novel therapies. Here we show an IBD therapeutic candidate LMT503, a substrate that modulates NADH quinone oxidoreductase (NQO1), which induces anti-inflammatory macrophage polarization by NAD+ enhancement. To determine the anti-inflammatory effect of LMT503, a dextran sulfate sodium (DSS)-induced colitis mouse model was used in this study. Treatment of bone marrow-derived macrophages (BMDMs) with LMT503 increased IL-10 and Arg1 levels but decreased levels of TNF-α, iNOS, and IL-6. LMT503 also increased levels of SIRT1, SIRT3, and SIRT6, suggesting that macrophages were driven to an anti-inflammatory character. In a murine DSS-induced colitis model, oral treatment with LMT503 ameliorated colonic inflammation and decreased infiltrating monocytes and neutrophils. Although NAD+ enhancement did not alter CX3CR1intCD206- or CX3CR1hiCD206+ colon macrophage population, it decreased levels of TNF-α and iNOS and increased IL-10 level, with colonic macrophages showing an anti-inflammatory character shift. Depletion of CX3CR1 expressing gut resident macrophages abrogated the immune regulatory effect of LMT503 in the colon. These data suggest that LMT503 is a therapeutic candidate that can target macrophages to drive polarization with an immunosuppressive character and ameliorate IBD.

Modulation of occludin, NF-κB, p-STAT3, and Th17 response by DJ-X-025 decreases inflammation and ameliorates experimental colitis

SCOPE

Inflammatory bowel disease (IBD) involves a range of immune-mediated disorders marked by systemic and local intestinal inflammation. We synthesized a novel compound DJ-X-025 and uncovered its anti-inflammatory properties using lipopolysaccharide (LPS)-induced RAW 264.7 macrophages in vitro and a dextran sodium sulfate (DSS)-induced model of colitis.

METHODS AND RESULTS

We evaluated the alteration in cell morphology, cytoskeletal proteins, and inflammatory markers of DJ-X-025 treated LPS-stimulated RAW 264.7 macrophages. We administered DJ-X-025 by oral gavage in DSS-induced colitis, examined colon histology, and alterations of immune cells by flow cytometry, and performed molecular studies using RT-qPCR and western blot analysis. DJ-X-025 treatment markedly altered the morphology of LPS-treated RAW 264.7 macrophages from elongated to round shapes, modulated actin and tubulin, and reduced the level of inflammatory markers like TNF-α, IL-1β, IL-6, and iNOS. Further, we observed that DJ-X-025 steered to improve colon length, muscularis mucosa thickness, and colon inflammatory score compared to the DSS group alone. DJ-X-025 effectively inverted the increased population of activated T cells, Th17, and macrophages in lamina propria by DSS treatment, leading to a substantial reduction in the inflammatory response in the colon. Strikingly, DJ-X-025 treatment enhanced the expression of occludin and diminished the expression of NF-κB and phosphorylation of STAT3 in the colon of DSS-treated mice compared to DSS-alone. Additionally, DJ-X-025 induced the expression of Foxp3 in the colon and, reduced systemic inflammatory cytokine/chemokine levels further supporting its immunomodulatory effects. These results suggest that DJ-X-025 is linked to the induction of occludin expression and decreased expression of p-STAT3/NF-κB and Th17 response in the colon, which together suppresses systemic and colon inflammatory cytokines for effective amelioration of experimental colitis.

CONCLUSION

These findings suggest that DJ-X-025 might be a promising therapeutic agent for the treatment of IBD.

Targeting ferroptosis in the treatment of ulcerative colitis by traditional Chinese medicine: A novel therapeutic strategies

BACKGROUND

The incidence of ulcerative colitis (UC) has been rising rapidly in recent years, and there is currently no effective method to prevent its recurrence. Owing to its long treatment duration, difficulty in treatment, prolonged remission, and high costs, it has attracted global attention. Exploring safe, effective, and sustainable treatment regimens has become an urgent global issue. Traditional Chinese medicine (TCM) has unique advantages such as low cost, low drug resistance, and fewer side effects, and has accumulated rich experience in the treatment of UC.

PURPOSE

Ferroptosis, as a new form of non-apoptotic cell death, is characterized by iron homeostatic imbalance and lipid peroxidation in the redox system. Studies have shown that inhibited ferroptosis in intestinal epithelial cells can protect the intestinal mucosa. Targeted intervention in ferroptosis may be a new direction for the treatment of UC.

METHODS

We conducted a systematic literature search with Google Scholar, PubMed, Web of Science, ScienceDirect and X-mol databases have been utilized to retrieve relevant literature up to October 2024, using keywords included ferroptosis, Inflammatory bowel disease (IBD), UC, Crohn's disease and TCM, Chinese traditional prescription, Chinese medicine extract and active ingredients. The existing literature was comprehensively studied and sorted out.

RESULTS

Currently, UC is mainly treated with drugs, including corticosteroids, amino salicylates, biologics, and immunomodulators, but drug resistance and adverse reactions are common. Increasing evidence suggests that TCM may treat UC by interfering with ferroptosis. Scholars have confirmed that TCM can inhibit ferroptosis, and recent studies have shown that TCM can not only inhibit iron dependent lipid peroxidation in intestinal cells but also enhance the antioxidant and anti-inflammatory abilities of intestinal mucosa, thus playing a role in the treatment of UC. This review explores the relevance of TCM intervention in ferroptosis and the treatment of UC, discusses the possible mechanisms of ferroptosis in UC, and aims to provide a basis for the diagnosis and treatment of UC.

CONCLUSION

It is revealed that TCM targeted ferroptosis has a good application prospect in the treatment of UC, providing a theoretical basis for elucidating the pathogenesis of UC and the study of TCM targeting ferroptosis regulating lipid metabolism in the treatment of UC, and providing a new perspective for the treatment of IBD in the future.

Beta-hydroxy-beta-methylbutyrate (HMB) ameliorates DSS-induced colitis by inhibiting ERK/NF-κB activation in macrophages

BACKGROUND

β-Hydroxy β-Methylbutyrate (HMB), derived from leucine, is known for its role in anti-oxidation and anti-inflammation. But, the application of HMB in IBD treatment is not fully understood, highlighting the requirement for further research.

PURPOSE

We aimed to examine the effects of HMB treatment on DSS-induced chronic colitis in mice and explore its underlying mechanisms.

METHODS

To simulate colonic inflammation, a murine colitis model was generated by using DSS induction. Critical indicators such as body weight, colon length, disease activity index (DAI), and gross pathology were thoroughly monitored. Immunohistochemistry assay was conducted to assess the expression of Occludin and F4/80. Flow cytometry was employed to evaluate the expression levels of CD80 and CD86. qPCR was performed to measure cytokine expression (IL-6, IL-1β, TNF-α, IL-22, CXCL2, iNOS). RNA sequencing was carried out using bone-marrow derived dendritic macrophage cells (BMDMs).

RESULTS

Our study indicates that HMB treatment substantially mitigated colonic damage in murine models of DSS-induced colitis, highlighting its anti-inflammatory potential. Notably, HMB significantly enhanced the expression of Occludin in these mice. Furthermore, HMB downregulated proinflammatory markers such as IL-6, IL-1β, and TNF-α as well as CXCL2 in the colon tissue. In vitro experiments also revealed that HMB reduced production of proinflammatory cytokines induced by DSS and suppressed the expression levels of CD80 and CD86 in macrophage cells. On a mechanistic level, we demonstrated the anti-inflammatory effects of HMB by reducing the phosphorylation of p-ERK and p-p65, thereby limiting cytokine production in both in vivo and in vitro settings.

CONCLUSION

These findings indicate that HMB possesses anti-inflammation against intestinal inflammation and may hold promise as a potential therapeutic candidate for IBD treatment. There's growing interest in combining traditional anti-inflammatory agents with supplements like HMB to improve outcomes in complex IBD cases. HMB's role in established muscle preservation and reduction of systemic inflammation as described in this study could make it a valuable adjunct in IBD therapy.

A Self-Assembled Metabolic Regulator Reprograms Macrophages to Combat Cytokine Storm and Boost Sepsis Immunotherapy

Sepsis, a life-threatening inflammatory disorder characterized by multiorgan failure, arises from a dysregulated immune response to infection. Modulating macrophage polarization has emerged as a promising strategy to control sepsis-associated inflammation. The endogenous metabolite itaconate has shown anti-inflammatory potential by suppressing the stimulator of interferon genes (STING) pathway, but its efficacy is inhibited by hyperactive glycolysis, which sustains macrophage overactivation. Here, we revealed a critical crosstalk between the itaconate-STING axis and glycolysis in macrophage-mediated inflammation. Building on this interplay, we developed a novel nanoparticle LDO (lonidamine disulfide 4-octyl-itaconate), a self-assembled metabolic regulator integrating an itaconate derivative with the glycolysis inhibitor Lonidamine. By concurrently targeting glycolysis and STING pathways, LDO reprograms macrophages to restore balanced polarization. In sepsis models, LDO effectively attenuates CCL2-driven cytokine storms, alleviates acute lung injury, and significantly enhances survival via metabolic reprogramming. This study offers a cytokine-regulatory strategy rooted in immunometabolism, providing a foundation for the translational development of immune metabolite-based sepsis therapies.

Nanotechnology-based drug delivery system for targeted therapy of ulcerative colitis from traditional Chinese medicine: A review

Ulcerative colitis (UC) is a chronic autoimmune disease and seriously affects the normal life of patients. Conventional therapeutic drugs are difficult to meet clinical needs. Traditional Chinese medicine (TCM) ingredients could effectively alleviate the symptoms of UC by anti-inflammatory, anti-oxidative, regulating the gut microbiota, and repairing the colonic epithelial barrier, but their low solubility and bioavailability severely limit their clinical application. Nano-drug delivery systems (NDDS) combined with TCM ingredients is a promising option for treating UC, and they could significantly enhance the stability, solubility, and bioavailability of TCM ingredients. The review describes the anti-UC mechanisms of TCM ingredients, systematically summarizes various kinds of NDDS for TCM ingredients according to different routes of administration, and highlights the advantages of NDDS for TCM ingredients in the treatmentof UC. In addition, we discuss the limitations of existing NDDS for TCM ingredients and the development direction in the future. This review will provide a basis for the future development of anti-UC NDDS for TCM ingredients.

The m6A reader HNRNPC is a key regulator in DSS-induced colitis by modulating macrophage phenotype

m6A regulators were demonstrated to modulate the functions of intestinal epithelial and immune cells in the ulcerative colitis. This study aimed to elucidate whether and how the m6A reader heterogeneous nuclear ribonucleoprotein C (HNRNPC) regulates macrophage function in the colitis. We observed elevated HNRNPC in the inflammatory Raw264.7 cells and macrophages in the dextran sodium sulfate (DSS)-induced colitis. Knocking down HNRNPC can mitigate LPS-induced activation of macrophages in vitro. Furthermore, adoptive transfer of macrophages with HNRNPC knockdown significantly alleviated colitis compared to those transfected with negative control siRNA. Additionally, RNA sequencing illuminated that HNRNPC regulated functions of macrophages by inhibiting alternative mRNA slicing, involving adjusting acute inflammatory response, and promoting cell chemotaxis and migration. Besides, HNRNPC can govern the stability of Itgb7, and Itgb7 might be an effective target for HNRNPC in macrophages. Our findings highlight the crucial role and therapeutic potential of HNRNPC inhibition in macrophages in alleviating colitis.

The Intestinal Macrophage-Intestinal Stem Cell Axis in Inflammatory Bowel Diseases: From Pathogenesis to Therapy

The gut plays a crucial role in digestion and immunity, so its balance is essential to overall health. This balance relies on dynamic interactions between intestinal epithelial cells, immune cells, and crypt stem cells. Inflammatory bowel disease (IBD), which consists of ulcerative colitis and Crohn's disease, is a chronic relapsing inflammatory disease of the gastrointestinal tract closely related to immune dysfunction. Stem cells, known for their ability to self-renew and differentiate, play an important role in repairing damaged intestinal epithelium and maintaining homeostasis in vivo. Macrophages are key gatekeepers of intestinal immune homeostasis and have a significant impact on IBD. Current research has focused on the link between epithelial cells and stem cells, but interactions with macrophages, which have been recognized as attractive targets for the development of new therapeutic approaches to disease, have been less explored. Recently, the developing field of immunometabolism has reinforced that metabolic reprogramming is a key determinant of macrophage function and subsequent disease progression. The aim of this review is to explore the role of the macrophage-stem cell axis in the maintenance of intestinal homeostasis and to summarize potential approaches to treating IBD by manipulating the cellular metabolism of macrophages, as well as the main opportunities and challenges faced. In summary, our overview provides a framework for understanding the critical role of macrophage immunometabolism in maintaining gut health and potential therapeutic targets.

Tea Extracellular Vesicle-Derived MicroRNAs Contribute to Alleviate Intestinal Inflammation by Reprogramming Macrophages

The clinical use of conventional medications for inflammatory bowel disease (IBD) is often limited by significant side effects. The extracellular vesicles derived from plant-based diets have shown promise in mitigating disease. Here, we discovered that natural extracellular vesicles from tea (TEVs) can achieve an appropriate transition from proinflammatory (M1) to anti-inflammatory (M2) macrophages and inhibit inflammation response both in vitro and in vivo. More importantly, the therapeutic effects of TEVs were at least partially attributed to RNA in a DSS-induced colitis model. Small RNA sequencing revealed a distinct enrichment of miRNAs in TEVs, with target genes primarily linked to IBD. TEVs were absorbed by macrophages in a time-dependent manner, carrying miRNAs that modulate gene expression within host cells. Notably, TEV-derived osa-miR166d-5p and gma-miR396a-3p were shown to enhance M2 macrophage polarization and reduce inflammation in vitro. Mechanistically, the osa-miR166d-5p- and gma-miR396a-3p-mediated targeting of the 3'-UTRs of AKT1 and IKBKB decreased NF-κB levels. Overall, we demonstrated that TEVs can ameliorate mouse colitis by reprogramming macrophage polarization and contain a unique miRNA repertoire, including osa-miR166d-5p and gma-miR396a-3p, with a novel function of alleviating intestinal inflammation.

TXM-CB13 Improves the Intestinal Mucosal Barrier and Alleviates Colitis by Inhibiting the ROS/TXNIP/TRX/NLRP3 and TLR4/MyD88/NF-κB/NLRP3 Pathways

The activation of inflammasomes (NLRP3 and NLRP1) is central to the pathogenesis of inflammatory bowel disease (IBD). Here we examined the protective effects of a thioredoxin-mimetic peptide CB13 (TXM-CB13), known for its antioxidative stress and anti-inflammatory properties. We examined the effects of TXM-CB13 on dextran sulfate sodium (DSS)-induced colitis and lipopolysaccharide (LPS)-induced NLRP3 inflammasome activation in RAW264.7 macrophages. TXM-CB13 appeared to alleviate symptoms of DSS-induced colitis and to significantly suppress the protein and mRNA levels of NLRP3, Mlck, and IL-1β in colonic tissues. Additionally, TXM-CB13 treatment increased the levels of the intestinal barrier proteins Occludin, ZO-1, and NLRP1, as shown through immunohistochemistry and Western blot analysis. In vitro, TXM-CB13 inhibited LPS-induced TLR4 signaling, reducing MyD88 levels and consequently attenuating the activation of the NF-κB pathways, including p-IκB-α/IκB-α and p-NF-κB-p65/NF-κB-p65. This inhibition further reduced the activation of the NLRP3 inflammasome components, NLRP3, ASC, Caspase-1, GSDMD, and IL-1β. In addition, TXM-CB13 prevented the ROS-mediated dissociation of TXNIP from TRX, inhibiting NLRP3 activation. These findings suggest that TXM-CB13 is a potential therapeutic candidate for IBD through its modulation of the TLR4/MyD88/NF-κB/NLRP3 and ROS/TXNIP/TRX/NLRP3 pathways.

Piezo1-specific Deletion in Macrophage Protects the Progression of Chronic Inflammatory Bowel Disease in Mice

BACKGROUND & AIMS

Piezo1, a recently identified mechanically activated nonselective cation channel protein, demonstrates sensitivity to various mechanical stimuli, such as matrix stiffness and shear stress. Although accumulating evidence implicates Piezo1 channels in numerous physiologic and pathophysiologic processes, its involvement in dextran sulfate sodium (DSS)-induced acute and chronic inflammatory bowel disease (IBD) remains incompletely understood. This study aimed to investigate the effect of Piezo1 channels in macrophage polarization and its associated functions in IBD.

METHODS

DSS-induced inflammatory bowel disease model was established in Piezo1td/Tdt or Piezo1fl/fl and Piezo1△LysM male mice. Additionally, bone marrow-derived macrophages from Piezo1fl/fl and Piezo1△LysM male mice were isolated to elucidate the downstream targets of Piezo1 and the associated underlying molecular mechanisms.

RESULTS

Our findings revealed that Piezo1 deficiency in macrophages could protect mice from DSS-induced chronic IBD, as evidenced by improved colon length and the preservation of colon structure. The mitigation of inflammation during chronic IBD progression was observed with Piezo1 deficiency in macrophages, characterized by reduced macrophage accumulation, M1 macrophage polarization, T helper 1 infiltration, and decreased inflammatory cytokine secretion. Further investigations unveiled that Piezo1-deficient macrophages inhibit the expression and activity of Nod-like receptor protein 3 and nuclear factor kappa B in colon tissues and bone marrow-derived macrophages while regulating the nuclear translocation of p65. Conversely, macrophage Piezo1 activation enhanced inflammatory cytokine secretion by activating Nod-like receptor protein 3/nuclear factor kappa B pathways.

CONCLUSIONS

Myeloid Piezo1 mediates colonic immune response, and disrupting Piezo1 inhibits the progression of chronic IBD. This study provides hitherto undocumented evidence of the pivotal role of macrophage Piezo1 channels in regulating the progression of chronic IBD. Targeting macrophage Piezo1 may offer a promising therapeutic strategy against chronic IBD.

Ginseng exosomes modulate M1/M2 polarisation by activating autophagy and target IKK/IкB/NF-кB to alleviate inflammatory bowel disease

BACKGROUND

Exosomes are involved in intercellular communication and regulation of the inflammatory microenvironment. In a previous study, we demonstrated that fresh ginseng exosomes (GEs) alleviated inflammatory bowel disease. However, the precise mechanism by which GEs activate the immune system and subsequently inhibit the formation of intestinal inflammatory microenvironment remains unknown.

METHODS

Herein, we investigated the effects of GEs on autophagy, macrophage polarisation, intestinal inflammation, and the epithelial barrier by means of transcriptome sequencing, network pharmacology, transmission electron microscopy, immunoblotting, flow cytometry and small molecule inhibitors.

RESULTS

GEs significantly activated autophagy and M2-like macrophage polarisation, which could be blocked by the autophagy inhibitor 3-methyladenine. In the co-culture system of macrophages and intestinal epithelial cells, macrophages treated with GEs secreted more interleukin-10 (IL-10) and significantly reduced Nitric oxide (NO) levels in intestinal epithelial cells in vitro. Furthermore, GEs acted directly on intestinal epithelial cells through the IKK/IкB/NF-кB signalling pathway to reduce inflammation and restore the intestinal barrier. Orally administered GEs could restore disrupted colonic barriers, alleviate inflammatory bowel responses, and regulate the polarisation of intestinal macrophages in vivo.

CONCLUSION

In summary, GEs may be a potential treatment for inflammatory bowel disease, and targeting autophagy and macrophage polarisation may help alleviate intestinal inflammation.