PTPN2 Regulates Interactions Between Macrophages and Intestinal Epithelial Cells to Promote Intestinal Barrier Function

Regulation of protein phosphorylation by PTPN2 and its small-molecule inhibitors/degraders as a potential disease treatment strategy

Protein tyrosine phosphatase nonreceptor type 2 (PTPN2) is an enzyme that dephosphorylates proteins with tyrosine residues, thereby modulating relevant signaling pathways in vivo. PTPN2 acts as tumor suppressor or tumor promoter depending on the context. In some cancers, such as colorectal, and lung cancer, PTPN2 defects could impair the protein tyrosine kinase pathway, which is often over-activated in cancer cells, and inhibit tumor development and progression. However, PTPN2 can also suppress tumor immunity by regulating immune cells and cytokines. The structure, functions, and substrates of PTPN2 in various tumor cells were reviewed in this paper. And we summarized the research status of small molecule inhibitors and degraders of PTPN2. It also highlights the potential opportunities and challenges for developing PTPN2 inhibitors as anticancer drugs.

Advanced glycation end products (AGEs) impair the intestinal epithelial barrier via STAT3 activation mediated by macrophages

Advanced glycation end products (AGEs) are a spectrum of complex compounds widely found in processed foods and frequently consumed by humans. AGEs are implicated in impairing the intestinal barrier, but the underlying mechanisms remain unclear. This study investigated the effects of three types of AGEs on gene expression of tight junctions (TJs) in colorectal epithelial HT-29 cells, and observed minimal alterations in TJs expression. Given the important role of subepithelial macrophages in regulating the intestinal barrier, we explored whether AGEs affect the intestinal barrier via the involvement of macrophages. Notably, a significant downregulation of TJs expression was observed when supernatants from AGEs-treated RAW264.7 macrophage cells were transferred to HT-29 cells. Further investigations indicated that AGEs increased IL-6 levels in RAW264.7 cells, subsequently triggering STAT3 activation and suppressing TJs expression in HT-29 cells. The role of STAT3 activation was confirmed by observing enhanced TJs expression in HT-29 cells following pretreatment with an inhibitor of STAT3 activation prior to the transfer of the conditioned medium. These findings demonstrated that AGEs impaired the intestinal barrier via macrophage-mediated STAT3 activation, shedding light on the mechanisms underlying AGEs-induced intestinal barrier injury and related food safety risks.

Gut bacterial quorum sensing molecules and their association with inflammatory bowel disease: Advances and future perspectives

Inflammatory Bowel Disease (IBD) is an enduring inflammatory disease of the gastrointestinal tract (GIT). The complexity of IBD, its profound impact on patient's quality of life, and its burden on healthcare systems necessitate continuing studies to elucidate its etiology, refine care strategies, improve treatment outcomes, and identify potential targets for novel therapeutic interventions. The discovery of a connection between IBD and gut bacterial quorum sensing (QS) molecules has opened exciting opportunities for research into IBD pathophysiology. QS molecules are small chemical messengers synthesized and released by bacteria based on population density. These chemicals are sensed not only by the microbial species but also by host cells and are essential in gut homeostasis. QS molecules are now known to interact with inflammatory pathways, therefore rendering them potential therapeutic targets for IBD management. Given these intriguing developments, the most recent research findings in this area are herein reviewed. First, the global burden of IBD and the disruptions of the gut microbiota and intestinal barrier associated with the disease are assessed. Next, the general QS mechanism and signaling molecules in the gut are discussed. Then, the roles of QS molecules and their connection with IBD are elucidated. Lastly, the review proposes potential QS-based therapeutic targets for IBD, offering insights into the future research trajectory in this field.

The landscape of miRNA-mRNA regulatory network and cellular sources in inflammatory bowel diseases: insights from text mining and single cell RNA sequencing analysis

Background

Inflammatory Bowel Diseases (IBDs), encompassing Ulcerative Colitis (UC) and Crohn's Disease (CD), are chronic, recurrent inflammatory conditions of the gastrointestinal tract. The microRNA (miRNA) -mRNA regulatory network is pivotal in the initiation and progression of IBDs. Although individual studies provide valuable insights into miRNA mechanisms in IBDs, they often have limited scope due to constraints in population diversity, sample size, sequencing platform variability, batch effects, and potential researcher bias. Our study aimed to construct comprehensive miRNA-mRNA regulatory networks and determine the cellular sources and functions of key miRNAs in IBD pathogenesis.

Methods

To minimize potential bias from individual studies, we utilized a text mining-based approach on published scientific literature from PubMed and PMC databases to identify miRNAs and mRNAs associated with IBDs and their subtypes. We constructed miRNA-mRNA regulatory networks by integrating both predicted and experimentally validated results from DIANA, Targetscan, PicTar, Miranda, miRDB, and miRTarBase (all of which are databases for miRNA target annotation). The functions of miRNAs were determined through gene enrichment analysis of their target mRNAs. Additionally, we used two large-scale single-cell RNA sequencing datasets to identify the cellular sources of miRNAs and the association of their expression levels with clinical status, molecular and functional alternation in CD and UC.

Results

Our analysis systematically summarized IBD-related genes using text-mining methodologies. We constructed three comprehensive miRNA-mRNA regulatory networks specific to IBD, CD, and UC. Through cross-analysis with two large-scale scRNA-seq datasets, we determined the cellular sources of the identified miRNAs. Despite originating from different cell types, hsa-miR-142, hsa-miR-145, and hsa-miR-146a were common to both CD and UC. Notably, hsa-miR-145 was identified as myofibroblast-specific in both CD and UC. Furthermore, we found that higher tissue repair and enhanced glucose and lipid metabolism were associated with hsa-miR-145 in myofibroblasts in both CD and UC contexts.

Conclusion

This comprehensive approach revealed common and distinct miRNA-mRNA regulatory networks in CD and UC, identified cell-specific miRNA expressions (notably hsa-miR-145 in myofibroblasts), and linked miRNA expression to functional alterations in IBD. These findings not only enhance our understanding of IBD pathogenesis but also offer promising diagnostic biomarkers and therapeutic targets for clinical practice in managing IBDs.

Diabetic Macrophage Exosomal miR-381-3p Inhibits Epithelial Cell Autophagy Via NR5A2

PURPOSE

To explore the mechanism underlying autophagy disruption in gingival epithelial cells (GECs) in diabetic individuals.

METHODS AND MATERIALS

Bone marrow-derived macrophages (BMDMs) and GECs were extracted from C57/bl and db/db mice, the exosomes (Exo) were isolated from BMDMs. qRT‒PCR and Western blotting were performed to analyse gene expression. The AnimalTFDB database was used to identify relevant transcription factors, and miRNA sequencing was utilised to identify relevant miRNAs with the aid of the TargetScan/miRDB/miRWalk databases. A dual-luciferase assay was conducted to verify intermolecular targeting relationships.

RESULTS

Similar to BMDMs, BMDM-derived Exos disrupted autophagy and exerted proinflammatory effects in GEC cocultures, and ATG7 may play a vital role. AnimalTFDB database analysis and dual-luciferase assays indicated that NR5A2 is the most relevant transcription factor that regulates Atg7 expression. SiRNA-NR5A2 transfection blocked autophagy in GECs and exacerbated inflammation, whereas NR5A2 upregulation restored ATG7 expression and ameliorated ExoDM-mediated inflammation. MiRNA sequencing, with TargetScan/miRDB/miRWalk analyses and dual-luciferase assays, confirmed that miR-381-3p is the most relevant miRNA that targets NR5A2. MiR-381-3p mimic transfection blocked autophagy in GECs and exacerbated inflammation, while miR-381-3p inhibitor transfection restored ATG7 expression and attenuated ExoDM-mediated inflammation.

CONCLUSION

BMDM-derived Exos, which carry miR-381-3p, inhibit NR5A2 and disrupt autophagy in GECs, increasing periodontal inflammation in diabetes.

Formyl peptide receptor 1 mitigates colon inflammation and maintains mucosal homeostasis through the inhibition of CREB-C/EBPβ-S100a8 signaling

Excessive inflammatory responses are the main characteristic of ulcerative colitis (UC). Activation of formyl peptide receptor 1 (FPR1) has been found to promote the proliferation and migration of epithelial cells, but its role and therapeutic potential in UC remain unclear. This study observed an increased expression of FPR1 in a mouse model of colitis. Interestingly, FPR1 deficiency exacerbated UC and increased the secretion of the proinflammatory mediator from immune cells (e.g. macrophages), S100a8, a member of the damage-associated molecular patterns. Notably, the administration of the FPR agonist Cmpd43 ameliorated colon injury in a preclinical mice model of UC, likely via inhibiting phosphorylation of cyclic adenosine monophosphate-response element-binding protein and expression of CCAAT/enhancer-binding protein β, which in turn suppressed the secretion of S100a8. In conclusion, these findings discovered a novel role of FPR1 in the development of colitis and will facilitate the development of FPR1-based pharmacotherapy to treat UC.

Ginkgetin improved experimental colitis by inhibiting intestinal epithelial cell apoptosis through EGFR/PI3K/AKT signaling

Excessive apoptosis of intestinal epithelial cells leads to intestinal barrier dysfunction, which is not only one of the pathological features of inflammatory bowel disease (IBD) but also a therapeutic target. A natural plant extract, Ginkgetin (GK), has been reported to have anti-apoptotic activity, but its role in IBD is unknown. This study aimed to explore whether GK has anti-colitis effects and related mechanisms. An experimental colitis model induced by dextran sulfate sodium (DSS) was established, and GK was found to relieve colitis in DSS-induced mice as evidenced by improvements in weight loss, colon shortening, Disease Activity Index (DAI), macroscopic and tissue scores, and proinflammatory mediators. In addition, in DSS mice and TNF-α-induced colonic organoids, GK protected the intestinal barrier and inhibited intestinal epithelial cell apoptosis, by improving permeability and inhibiting the number of apoptotic cells and the expression of key apoptotic regulators (cleaved caspase 3, Bax and Bcl-2). The underlying mechanism of GK's protective effect was explored by bioinformatics, rescue experiments and molecular docking, and it was found that GK might directly target and activate EGFR, thereby interfering with PI3K/AKT signaling to inhibit apoptosis of intestinal epithelial cells in vivo and in vitro. In conclusion, GK inhibited intestinal epithelial apoptosis in mice with experimental colitis, at least in part, by activating EGFR and interfering with PI3K/AKT activation, explaining the underlying mechanism for ameliorating colitis, which may provide new options for the treatment of IBD.

YTHDC1 inhibits autophagy-dependent NF-κB signaling by stabilizing Beclin1 mRNA in macrophages

BACKGROUND

YTHDC1, a key m(6)A nuclear reader, plays a crucial role in regulating mRNA splicing, export, and stability. However, the functional significance and regulatory mechanisms of YTHDC1 in inflammatory bowel disease (IBD) remain to be explored.

METHODS

We established a dextran sulfate sodium (DSS)-induced murine colitis model in vivo and LPS/IFN-γ-stimulated macrophage inflammation in vitro. The expression of YTHDC1 was determined. Colocalization of YTHDC1 and macrophages was assayed by immunofluorescence staining. LV-YTHDC1 or shYTHDC1 lentiviruses were applied for YTHDC1 overexpression or inhibition. For NF-κB inhibition, JSH-23 was utilized. The interaction of YTHDC1 and Beclin1 mRNA was determined by RIP, and the m6A modification of Beclin1 was confirmed by MeRIP.

RESULTS

In DSS-induced colitis and LPS/IFN-γ-treated RAW264.7 macrophages, we observed a significant downregulation of YTHDC1. Overexpression of YTHDC1 resulted in decreased levels of iNOS, CD86, and IL-6 mRNA, along with inhibited NF-κB activation in LPS/IFN-γ-treated RAW264.7 cells. Conversely, downregulation of YTHDC1 promoted iNOS expression and inhibited autophagy. Additionally, the effect of YTHDC1 knockdown on CD86 and IL-6 mRNA induced by LPS/IFN-γ was abolished by the NF-κB inhibitor JSH-23. Mechanistically, YTHDC1 interacted with Beclin1 mRNA, thereby stabilizing Beclin1 mRNA and enhancing Beclin1 expression and autophagy. These effects ultimately led to the inhibition of NF-κB signaling in LPS/IFN-γ-challenged macrophages.

CONCLUSIONS

YTHDC1 inhibited the macrophage-mediated inflammatory response by stabilizing Beclin1 mRNA, which may be a potential therapeutic target for the treatment of IBD.

Upregulation of TCPTP in Macrophages Is Involved in IL-35 Mediated Attenuation of Experimental Colitis

Ulcerative colitis (UC) is a chronic intestinal inflammatory disease with complex etiology. Interleukin-35 (IL-35), as a cytokine with immunomodulatory function, has been shown to have therapeutic effects on UC, but its mechanism is not yet clear. Therefore, we constructed Pichia pastoris stably expressing IL-35 which enables the cytokines to reach the diseased mucosa, and explored whether upregulation of T-cell protein tyrosine phosphatase (TCPTP) in macrophages is involved in the mechanisms of IL-35-mediated attenuation of UC. After the successful construction of engineered bacteria expressing IL-35, a colitis model was successfully induced by giving BALB/c mice a solution containing 3% dextran sulfate sodium (DSS). Mice were treated with Pichia/IL-35, empty plasmid-transformed Pichia (Pichia/0), or PBS by gavage, respectively. The expression of TCPTP in macrophages (RAW264.7, BMDMs) and intestinal tissues after IL-35 treatment was detected. After administration of Pichia/IL-35, the mice showed significant improvement in weight loss, bloody stools, and shortened colon. Colon pathology also showed that the inflammatory condition of mice in the Pichia/IL-35 treatment group was alleviated. Notably, Pichia/IL-35 treatment not only increases local M2 macrophages but also decreases the expression of inflammatory cytokine IL-6 in the colon. With Pichia/IL-35 treatment, the proportion of M1 macrophages, Th17, and Th1 cells in mouse MLNs were markedly decreased, while Tregs were significantly increased. In vitro experiments, IL-35 significantly promoted the expression of TCPTP in macrophages stimulated with LPS. Similarly, the mice in the Pichia/IL-35 group also expressed more TCPTP than that of the untreated group and the Pichia/0 group.

Timosaponin BⅡ reduces colonic inflammation and alleviates DSS-induced ulcerative colitis by inhibiting NLRP3

ETHNOPHARMACOLOGICAL RELEVANCE

The Timosaponin BⅡ (TBⅡ) is one of the main active components of the traditional Chinese medicine Anemarrhena asphodeloides, and it is a steroidal saponin with various pharmacological activities such as anti-oxidation, anti-inflammatory and anti-apoptosis. However, its role in acute ulcerative colitis remains unexplored thus far.

AIM OF THE STUDY

This study aims to investigate the protective effect of TBⅡ against dextran sulfate sodium (DSS)-induced ulcerative colitis in mice and elucidate its underlying mechanisms.

METHODS

Wild-type (WT) and NLRP3 knockout (NLRP3-/-) mice were applied to evaluate the protective effect of TBⅡ in DSS-induced mice colitis. Pharmacological inhibition of NLRP3 or adenovirus-mediated NLRP3 overexpression in bone marrow-derived macrophages (BMDM) from WT mice and colonic epithelial HCoEpiC cells was used to assess the role of TBⅡ in LPS + ATP-induced cell model. RNA-seq, ELISA, western blots, immunofluorescence staining, and expression analysis by qPCR were performed to examine the alterations of colonic NLRP3 expression in DSS-induced colon tissues and LPS + ATP-induced cells, respectively.

RESULTS

In mice with DSS-induced ulcerative colitis, TBⅡ treatment attenuated clinical symptoms, repaired the intestinal mucosal barrier, reduced inflammatory infiltration, and alleviated colonic inflammation. RNA-seq analysis and protein expression levels demonstrated that TBⅡ could prominently inhibit NLRP3 signaling. TBⅡ-mediated NLRP3 inhibition was associated with alleviating intestinal permeability and inflammatory response via the blockage of communication between epithelial cells and macrophages, probably in an NLRP3 inhibition mechanism. However, pharmacological inhibition of NLRP3 by MCC950 or Ad-NLRP3 mediated NLRP3 overexpression significantly impaired the TBⅡ-mediated anti-inflammatory effect. Mechanistically, TBⅡ-mediated NLRP3 inhibition may be partly associated with the suppression of NF-κB, a master pro-inflammatory factor for transcriptional regulation of NLRP3 expression in the priming step. Moreover, co-treatment TBⅡ with NF-κB inhibitor BAY11-7082 partly impaired TBⅡ-mediated NLRP3 inhibition, and consequently affected the IL-1β mature and secretion. Importantly, TBⅡ-mediated amelioration was not further enhanced in NLPR3-/- mice.

CONCLUSION

TBⅡ exerted a prominent protective effect against DSS-induced colitis via regulation of alleviation of intestinal permeability and inflammatory response via the blockage of crosstalk between epithelial cells and macrophages in an NLRP3-mediated inhibitory mechanism. These beneficial effects could make TBⅡ a promising drug for relieving colitis.

Predicting Risks of Dry Eye Disease Development Using a Genome-Wide Polygenic Risk Score Model

Purpose

The purpose of this study was to conduct a large-scale genome-wide association study (GWAS) and construct a polygenic risk score (PRS) for risk stratification in patients with dry eye disease (DED) using the Taiwan Biobank (TWB) databases.

Methods

This retrospective case-control study involved 40,112 subjects of Han Chinese ancestry, sourced from the publicly available TWB. Cases were patients with DED (n = 14,185), and controls were individuals without DED (n = 25,927). The patients with DED were further divided into 8072 young (<60 years old) and 6113 old participants (≥60 years old). Using PLINK (version 1.9) software, quality control was carried out, followed by logistic regression analysis with adjustments for sex, age, body mass index, depression, and manic episodes as covariates. We also built PRS prediction models using the standard clumping and thresholding method and evaluated their performance (area under the curve [AUC]) through five-fold cross-validation.

Results

Eleven independent risk loci were identified for these patients with DED at the genome-wide significance levels, including DNAJB6, MAML3, LINC02267, DCHS1, SIRPB3P, HULC, MUC16, GAS2L3, and ZFPM2. Among these, MUC16 encodes mucin family protein. The PRS model incorporated 932 and 740 genetic loci for young and old populations, respectively. A higher PRS score indicated a greater DED risk, with the top 5% of PRS individuals having a 10-fold higher risk. After integrating these covariates into the PRS model, the area under the receiver operating curve (AUROC) increased from 0.509 and 0.537 to 0.600 and 0.648 for young and old populations, respectively, demonstrating the genetic-environmental interaction.

Conclusions

Our study prompts potential candidates for the mechanism of DED and paves the way for more personalized medication in the future.

Translational Relevance

Our study identified genes related to DED and constructed a PRS model to improve DED prediction.

Hypoxia, hypoxia-inducible factors and inflammatory bowel diseases

Adequate oxygen supply is essential for maintaining the body's normal physiological function. In chronic inflammatory conditions such as inflammatory bowel disease (IBD), insufficient oxygen reaching the intestine triggers the regulatory system in response to environmental changes. However, the pathogenesis of IBD is still under investigation. Recent research has highlighted the significant role of hypoxia in IBD, particularly the involvement of hypoxia-inducible factors (HIF) and their regulatory mechanisms, making them promising therapeutic targets for IBD. This review will delve into the role of hypoxia, HIF, and the associated hypoxia-inflammatory microenvironment in the context of IBD. Potential interventions for addressing these challenging gastrointestinal inflammatory diseases will also be discussed within this framework.

Advancements in understanding bacterial enteritis pathogenesis through organoids

Bacterial enteritis has a substantial role in contributing to a large portion of the global disease burden and serves as a major cause of newborn mortality. Despite advancements gained from current animal and cell models in improving our understanding of pathogens, their widespread application is hindered by apparent drawbacks. Therefore, more precise models are imperatively required to develop more accurate studies on host-pathogen interactions and drug discovery. Since the emergence of intestinal organoids, massive studies utilizing organoids have been conducted to study the pathogenesis of bacterial enteritis, revealing new mechanisms and validating established ones. In this review, we focus on the advancements of several bacterial pathogenesis mechanisms observed in intestinal organoid/enteroid models, exploring the host response and bacterial effectors during the infection process. Finally, we address the features that warrant additional investigation or could be enhanced in existing organoid models in order to guide future research endeavors.

Bowel function and inflammation: Is motility the other side of the coin?

Digestion and intestinal absorption allow the body to sustain itself and are the emblematic functions of the bowel. On the flip side, functions also arise from its role as an interface with the environment. Indeed, the gut houses microorganisms, collectively known as the gut microbiota, which interact with the host, and is the site of complex immune activities. Its role in human pathology is complex and scientific evidence is progressively elucidating the functions of the gut, especially regarding the pathogenesis of chronic intestinal diseases and inflammatory conditions affecting various organs and systems. This editorial aims to highlight and relate the factors involved in the pathogenesis of intestinal and systemic inflammation.

Evaluation of the therapeutic efficacy of different doses of LT4 in pregnant women with high-normal TSH levels and TPOAb positivity in the first half of pregnancy

BACKGROUND

The objective was to investigate the efficacy of different doses of levothyroxine therapy among pregnant women exhibiting high-normal thyroid stimulating hormone levels and positive thyroid peroxidase antibodies throughout the first half of pregnancy.

METHODS

Pregnant women exhibiting high-normal thyroid stimulating hormone levels and thyroid peroxidase antibodies positivity throughout the initial half of pregnancy were selected from January 2021 to September 2023. Based on the different doses of levothyroxine, the pregnant women were categorized into the nonintervention group (G0, 122 women), 25 µg levothyroxine intervention group (G25, 69 women), and 50 µg levothyroxine intervention group (G50, 58 women). Serum parameters, gastrointestinal symptoms, small intestinal bacterial overgrowth (SIBO), maternal and neonatal outcomes were compared after the intervention among the three groups.

RESULTS

After the intervention, in the G25 and G50 groups, the thyroid stimulating hormone, triglyceride and low-density lipoprotein levels were notably less in contrast to those in the G0 group (P < 0.05). The rates of abdominal distension and SIBO in the G25 and G50 groups were notably lower in contrast to the G0 group (P = 0.043 and 0.040, respectively). The G50 group had a lower rate of spontaneous abortion and premature membrane rupture than the G0 group (P = 0.01 and 0.015, respectively). Before 11+ 2 weeks of gestation and at thyroid peroxidase antibodies levels ≥ 117 IU/mL, in contrast to the G0 group, the G50 group experienced a decreased rate of spontaneous abortion (P = 0.008). The G50 group had significantly higher newborn weight than the G0 group (P = 0.014), as well as a notably longer newborn length than the G0 and G25 groups (P = 0.005).

CONCLUSIONS

For pregnant women with high-normal thyroid stimulating hormone levels and thyroid peroxidase antibodies positive during the first half of pregnancy, supplementation with 50 µg levothyroxine was more effective in improving their blood lipid status and gastrointestinal symptoms, reducing the incidence of SIBO and premature rupture of membranes, and before 11+2 weeks, TPOAb ≥ 117 IU/mL proved more beneficial in mitigating the risk of spontaneous abortion.

Intestinal macrophages in pathogenesis and treatment of gut leakage: current strategies and future perspectives

Macrophages play key roles in tissue homeostasis, defense, disease, and repair. Macrophages are highly plastic and exhibit distinct functional phenotypes based on micro-environmental stimuli. In spite of several advancements in understanding macrophage biology and their different functional phenotypes in various physiological and pathological conditions, currently available treatment strategies targeting macrophages are limited. Macrophages' high plasticity and diverse functional roles-including tissue injury and wound healing mechanisms-mark them as potential targets to mine for efficient therapeutics to treat diseases. Despite mounting evidence on association of gut leakage with several extraintestinal diseases, there is no targeted standard therapy to treat gut leakage. Therefore, there is an urgent need to develop therapeutic strategies to treat this condition. Macrophages are the cells that play the largest role in interacting with the gut microbiota in the intestinal compartment and exert their intended functions in injury and repair mechanisms. In this review, we have summarized the current knowledge on the origins and phenotypes of macrophages. The specific role of macrophages in intestinal barrier function, their role in tissue repair mechanisms, and their association with gut microbiota are discussed. In addition, currently available therapies and the putative tissue repair mediators of macrophages for treating microbiota dysbiosis induced gut leakage are also discussed. The overall aim of this review is to convey the intense need to screen for microbiota induced macrophage-released prorepair mediators, which could lead to the identification of potential candidates that could be developed for treating the leaky gut and associated diseases.

Evaluation of nanoparticle albumin-bound paclitaxel loaded macrophages for glioblastoma treatment based on a microfluidic chip

Introduction: Glioblastoma (GBM) is a primary brain malignancy with a dismal prognosis and remains incurable at present. In this study, macrophages (MΦ) were developed to carry nanoparticle albumin-bound paclitaxel (nab-PTX) to form nab-PTX/MΦ. The aim of this study is to use a GBM-on-a-chip to evaluate the anti-GBM effects of nab-PTX/MΦ. Methods: In this study, we constructed nab-PTX/MΦ by incubating live MΦ with nab-PTX. We developed a microfluidic chip to co-culture GBM cells and human umbilical vein endothelial cells, mimicking the simplified blood-brain barrier and GBM. Using a syringe pump, we perform sustainable perfusion of nutrient media. To evaluate the anti-GBM effects nab-PTX/MΦ, we treated the GBM-on-a-chip model with nab-PTX/MΦ and investigated GBM cell proliferation, migration, and spheroid formation. Results: At the chosen concentration, nab-PTX did not significantly affect the viability, chemotaxis and migration of MΦ. The uptake of nab-PTX by MΦ occurred within 1 h of incubation and almost reached saturation at 6 h. Additionally, nab-PTX/MΦ exhibited the M1 phenotype, which inhibits tumor progression. Following phagocytosis, MΦ were able to release nab-PTX, and the release of nab-PTX by MΦ had nearly reached its limit at 48 h. Compared with control group and blank MΦ group, individual nab-PTX group and nab-PTX/MΦ group could inhibit tumor proliferation, invasion and spheroid formation. Meanwhile, the anti-GBM effect of nab-PTX/MΦ was more significant than nab-PTX. Discussion: Our findings demonstrate that nab-PTX/MΦ has a significant anti-GBM effect compared to individual nab-PTX or MΦ administration, suggesting MΦ as potential drug delivery vectors for GBM therapy. Furthermore, the developed GBM-on-a-chip model provides a potential ex vivo platform for innovative cell-based therapies and tailored therapeutic strategies for GBM.

Microfluidic platform for omics analysis on single cells with diverse morphology and size: A review

BACKGROUND

Microfluidic techniques have emerged as powerful tools in single-cell research, facilitating the exploration of omics information from individual cells. Cell morphology is crucial for gene expression and physiological processes. However, there is currently a lack of integrated analysis of morphology and single-cell omics information. A critical challenge remains: what platform technologies are the best option to decode omics data of cells that are complex in morphology and size?

RESULTS

This review highlights achievements in microfluidic-based single-cell omics and isolation of cells based on morphology, along with other cell sorting methods based on physical characteristics. Various microfluidic platforms for single-cell isolation are systematically presented, showcasing their diversity and adaptability. The discussion focuses on microfluidic devices tailored to the distinct single-cell isolation requirements in plants and animals, emphasizing the significance of considering cell morphology and cell size in optimizing single-cell omics strategies. Simultaneously, it explores the application of microfluidic single-cell sorting technologies to single-cell sequencing, aiming to effectively integrate information about cell shape and size.

SIGNIFICANCE AND NOVELTY

The novelty lies in presenting a comprehensive overview of recent accomplishments in microfluidic-based single-cell omics, emphasizing the integration of different microfluidic platforms and their implications for cell morphology-based isolation. By underscoring the pivotal role of the specialized morphology of different cells in single-cell research, this review provides robust support for delving deeper into the exploration of single-cell omics data.

The miR-7/EGFR axis controls the epithelial cell immunomodulation and regeneration and orchestrates the pathology in inflammatory bowel disease

INTRODUCTION

The epithelial immunomodulation and regeneration are intrinsic critical events against inflammatory bowel disease (IBD). MiR-7 is well documented as a promising regulator in the development of various diseases including inflammatory diseases.

OBJECTIVES

This study aimed to assess the effect of miR-7 in intestinal epithelial cells (IECs) in IBD.

METHODS

MiR-7def mice were given dextran sulfate sodium (DSS) to induce enteritis model. The infiltration of inflammatory cells was measured by FCM and immunofluorescence assay. 5'deletion assay and EMSA assays were performed to study the regulatory mechanism of miR-7 expression in IECs. The inflammatory signals and the targets of miR-7 were analyzed by RNA-seq and FISH assay. IECs were isolated from miR-7def, miR-7oe and WT mice to identify the immunomodulation and regeneration capacity. IEC-specific miR-7 silencing expression vector was designed and administered by the tail vein into murine DSS-induced enteritis model to evaluate the pathological lesions of IBD.

RESULTS

We found miR-7 deficiency improved the pathological lesions of DSS-induced murine enteritis model, accompanied by elevated proliferation and enhanced transduction of NF-κB/AKT/ERK signals in colonic IECs, as well as decreased local infiltration of inflammatory cells. MiR-7 was dominantly upregulated in colonic IECs in colitis. Moreover, the transcription of pre-miR-7a-1, orchestrated by transcription factor C/EBPα, was a main resource of mature miR-7 in IECs. As for the mechanism, EGFR, a miR-7 target gene, was downregulated in colonic IECs in colitis model and Crohn's disease patients. Furthermore, miR-7 also controlled the proliferation and inflammatory-cytokine secretion of IECs in response to inflammatory-signals through EGFR/NF-κB/AKT/ERK pathway. Finally, IEC-specific miR-7 silencing promoted the proliferation and transduction of NF-κB pathway in IECs and alleviated the pathological damage of colitis.

CONCLUSION

Our results present the unknown role of miR-7/EGFR axis in IEC immunomodulation and regeneration in IBD and might provide clues for the application of miRNA-based therapeutic strategies in colonic diseases.

Cellular and Molecular Roles of Immune Cells in the Gut-Brain Axis in Migraine

Migraine is a complex and multi-system dysfunction. The realization of its pathophysiology and diagnosis is developing rapidly. Migraine has been linked to gastrointestinal disorders such as irritable bowel syndrome and celiac disease. There is also direct and indirect evidence for a relationship between migraine and the gut-brain axis, but the exact mechanism is not yet explained. Studies have shown that this interaction appears to be influenced by a variety of factors, such as inflammatory mediators, gut microbiota, neuropeptides, and serotonin pathways. Recent studies suggest that immune cells can be the potential tertiary structure between migraine and gut-brain axis. As the hot interdisciplinary subject, the relationship between immunology and gastrointestinal tract is now gradually clear. Inflammatory signals are involved in cellular and molecular responses that link central and peripheral systems. The gastrointestinal symptoms associated with migraine and experiments associated with antibiotics have shown that the intestinal microbiota is abnormal during the attacks. In this review, we focus on the mechanism of migraine and gut-brain axis, and summarize the tertiary structure between immune cells, neural network, and gastrointestinal tract.

Trichinella-derived protein ameliorates colitis by altering the gut microbiome and improving intestinal barrier function

BACKGROUND

Inflammatory bowel disease (IBD) encompasses Crohn's Disease and Ulcerative Colitis. Reports have highlighted the potential use of helminths or their byproducts as a possible treatment for IBD; however, the mechanisms underlying their ability to modulate inflammation remain incompletely understood. In the present study, we analyze the possible mechanism of a serine protease inhibitor from adult T. spiralis excretion-secretion products (rTsSPI) on the improvement of colitis.

METHODS

The immune protective effect of rTsSPI was studied by using DSS or Salmonella-induced colitis in female C56BL/6 mice. The effect of rTsSPI on the immune and inflammatory responses, gut microbiota, permeability of colon epithelium and junction proteins was analyzed.

RESULTS

Treating mice with rTsSPI induced type 2 immunity and significantly attenuated clinical symptoms, macroscopical and histological features of DSS or bacteria-induced colonic inflammation. This was accompanied by decreasing neutrophil recruitment in the colonic lamina propria, and reducing TNF-α mRNA levels in the colon; in contrast, the recruitment of M2 macrophages, the expression level of IL-10 and adhesion molecules increased in the colon tissue. Moreover, treatment with rTsSPI led to an improvement in gut microbiota diversity, as well as an increase in the abundance of the bacterial genera Bifidobacterium and Ruminclostridium 5.

CONCLUSIONS

Collective findings suggest that pretreatment with rTsSPI can ameliorate colitis in mice by inducing a Th2-type response with M2 macrophages. Data also indicate that immunotherapy with rTsSPI represents an additional strategy to ameliorate inflammatory processes in IBD by enhancing probiotic colonization and maintaining intestinal epithelial barrier function.

D-Mannose promotes recovery from experimental colitis by inducing AMPK phosphorylation to stimulate epithelial repair

Delayed mucosal healing and impaired intestinal epithelial barrier function have been implicated in the pathogenesis of ulcerative colitis (UC). Accordingly, restoration of epithelial barrier function as a means to reshape mucosal homeostasis represents an important strategy for use in the treatment of UC. In this study, we examined the role and mechanisms of D-mannose in the recovery of colitis as assessed in both animal and cell models. We found that D-mannose ameliorated inflammation, promoted mucosal healing in the colon and therefore was able to induce the recovery of UC. Furthermore, D-mannose increased the expression of tight junction (TJ) proteins and reduced the intestinal permeability during the recovery of colitis. Moreover, D-mannose inhibited M1 macrophage polarization and promoted M2 macrophage polarization via inducing AMPK phosphorylation while reducing mTOR phosphorylation in both models. In addition, increased TJ protein expression and decreased paracellular permeability were observed in NCM460 cells when incubated with the supernatants of D-mannose-treated RAW264.7 cells, suggesting that M1/M2 polarization induced by D-mannose modulates the expression of TJ proteins. Further study showed that D-mannose significantly upregulated the expression of TJ proteins in DSS-treated NCM460 cells by inducing AMPK phosphorylation, indicating a direct protective effect on epithelial cells. Finally, the protective effects of D-mannose were significantly abrogated by the presence of compound C, an AMPK inhibitor. Taken together, our data indicate that D-mannose can alleviate inflammation and foster epithelial restitution in UC recovery by inducing the TJ protein expression, which are achieved by inducing AMPK phosphorylation in the epithelium and/or macrophages.

Involvement of Embryo-Derived and Monocyte-Derived Intestinal Macrophages in the Pathogenesis of Inflammatory Bowel Disease and Their Prospects as Therapeutic Targets

Inflammatory bowel disease (IBD) is a group of intestinal inflammatory diseases characterized by chronic, recurrent, remitting, or progressive inflammation, which causes the disturbance of the homeostasis between immune cells, such as macrophages, epithelial cells, and microorganisms. Intestinal macrophages (IMs) are the largest population of macrophages in the body, and the abnormal function of IMs is an important cause of IBD. Most IMs come from the replenishment of blood monocytes, while a small part come from embryos and can self-renew. Stimulated by the intestinal inflammatory microenvironment, monocyte-derived IMs can interact with intestinal epithelial cells, intestinal fibroblasts, and intestinal flora, resulting in the increased differentiation of proinflammatory phenotypes and the decreased differentiation of anti-inflammatory phenotypes, releasing a large number of proinflammatory factors and aggravating intestinal inflammation. Based on this mechanism, inhibiting the secretion of IMs' proinflammatory factors and enhancing the differentiation of anti-inflammatory phenotypes can help alleviate intestinal inflammation and promote tissue repair. At present, the clinical medication of IBD mainly includes 5-aminosalicylic acids (5-ASAs), glucocorticoid, immunosuppressants, and TNF-α inhibitors. The general principle of treatment is to control acute attacks, alleviate the condition, reduce recurrence, and prevent complications. Most classical IBD therapies affecting IMs function in a variety of ways, such as inhibiting the inflammatory signaling pathways and inducing IM2-type macrophage differentiation. This review explores the current understanding of the involvement of IMs in the pathogenesis of IBD and their prospects as therapeutic targets.

ASTRAGALOSIDE Ⅳ MODULATES GUT MACROPHAGES M1/M2 POLARIZATION BY RESHAPING GUT MICROBIOTA AND SHORT CHAIN FATTY ACIDS IN SEPSIS

ABSTRACT

M1 macrophage-mediated inflammation is critical in sepsis. We previously found the protective role of astragaloside intravenous (AS-IV) in sepsis-associated gut impairment, whose specific mechanism remains unknown. Gut microbiota modulates gut homeostatic balance to avoid excessive inflammation. Here, we aimed to investigate effects of AS-IV on gut macrophages polarization and potential roles of gut microbiota and short chain fatty acids (SCFAs) in septic gut damage. Mice were pretreated by AS-IV gavage for 7 days before cecal ligation and puncture. M1 polarization of gut lamina propria macrophages (LpMs) was promoted by cecal ligation and puncture, accompanied by abnormal cytokines release and intestinal barrier dysfunction. NLRP3 inflammasome was activated in M1 LpMs. 16S rRNA sequencing demonstrated gut microbiota imbalance. The levels of acetate, propionate, and butyrate in fecal samples decreased. Notably, AS-IV reversed LpMs M1/M2 polarization, lightened gut inflammation and barrier injury, reduced NLRP3 inflammasome expression in LpMs, restored the diversity of gut microbiome, and increased butyrate levels. Similarly, these benefits were mimicked by fecal microbiota transplantation or exogenous butyrate supplementation. In Caco-2 and THP-1 cocultured model, LPS and interferon γ caused THP-1 M1 polarization, Caco-2 barrier impairment, abnormal cytokines release, and high NLRP3 inflammasome expression in THP-1 cells, all of which were mitigated by butyrate administration. However, these protective effects of butyrate were abrogated by NLRP3 gene overexpression in THP-1. In conclusion, AS-IV can ameliorate sepsis-induced gut inflammation and barrier dysfunction by modulating M1/M2 polarization of gut macrophages, whose underlying mechanism may be restoring gut microbiome and SCFA to restrain NLRP3 inflammasome activation.

Macrophage polarization in inflammatory bowel disease

The growing prevalence of inflammatory bowel disease (IBD) has encouraged research efforts, which have contributed to gradual improvements in our understanding of IBD diagnosis and therapeutic approaches. The pathogenesis of IBD has not been fully elucidated; however, the combined actions of environmental, genetic, immune factors, and microbial organisms are believed to cause IBD. In the innate immune system, macrophages play important roles in maintaining intestinal health and in the development of IBD. Macrophages can be polarized from M0 into several phenotypes, among which M1 and M2 play critical roles in IBD development and the repair of intestinal homeostasis and damage. Certain macrophage-related IBD studies already exist; however, the functions of each phenotype have not been fully elucidated. As technology develops, understanding the link between macrophages and IBD has increased, including the growing knowledge of the developmental origins of intestinal macrophages and their performance of comprehensive functions. This review describes macrophage polarization in IBD from the perspectives of macrophage development and polarization, macrophage changes in homeostasis and IBD, metabolic changes, and the mechanisms of macrophage polarization in IBD. The discussion of these topics provides new insights into immunotherapy strategies for IBD. Video Abstract.

Hyaluronic acid/inulin-based nanocrystals with an optimized ratio of indigo and indirubin for combined ulcerative colitis therapy via immune and intestinal flora regulation

Indigo (IND) and indirubin (INB) have demonstrated a synergistic effect in treating ulcerative colitis at a ratio of 7.5:1. However, the colon mucus layer, a critical physiological barrier against external threats, is also a biological barrier, limiting the potential for effective drug delivery to the lamina propria for regulating inflammatory cells. Inspired by the potential of Hyaluronic acid (HA), to enhance cellular uptake by inflammatory cells, and Pluronic® F127 (F127), known for overcoming the mucus barrier, this study innovatively developed INB/IND nanosuspensions by co-modifying with F127 and HA. Moreover, inulin serves a dual purpose as a spray protective agent and a regulator of intestinal flora. Therefore, it was incorporated into INB/IND nanosuspensions for subsequent spray drying, resulting in the preparation of INB/IND nanocrystals (INB/IND-NC). The mucus penetration of INB/IND-NC was 24.30 times that of the control group. Besides, INB/IND-NC exhibited enhanced cellular uptake properties proximately twice that of Raw INB/IND. Importantly, INB/IND-NC exhibited improved therapeutic efficacy in DSS-induced mice by regulating the expression of cytokines, regulating immune responses via downregulating the expression of macrophages, neutrophils, and dendritic cells and maintaining intestinal flora homeostasis. Our study provides a new perspective for applying natural products for treating inflammatory diseases.

Artemether Attenuates Gut Barrier Dysfunction and Intestinal Flora Imbalance in High-Fat and High-Fructose Diet-Fed Mice

Intestinal inflammation is a key determinant of intestinal and systemic health, and when our intestines are damaged, there is disruption of the intestinal barrier, which in turn induces a systemic inflammatory response. However, the etiology and pathogenesis of inflammatory diseases of the intestine are still not fully understood. Artemether (ART), one of the artemisinin derivatives, has been widely used to treat malaria. Nevertheless, the effect of ART on intestinal inflammation remains unclear. The present study intended to elucidate the potential mechanism of ART in diet-induced intestinal injury. A high-fat and high-fructose (HFHF) diet-induced mouse model of intestinal injury was constructed, and the mice were treated with ART to examine their role in intestinal injury. RT-qPCR, Western blotting, immunohistochemical staining, and 16S rRNA gene sequencing were used to investigate the anti-intestinal inflammation effect and mechanism of ART. The results indicated that ART intervention may significantly ameliorate the intestinal flora imbalance caused by the HFHF diet and alleviate intestinal barrier function disorders and inflammatory responses by raising the expression of tight junction proteins ZO-1 and occludin and decreasing the expression of pro-inflammatory factors TNF-α and IL-1β. Moreover, ART intervention restrained HFHF-induced activation of the TLR4/NF-κB p65 pathway in colon tissue, which may be concerned with the potential protective effect of ART on intestinal inflammation. ART might provide new insights into further explaining the mechanism of action of other metabolic diseases caused by intestinal disorders.

Engineered baicalein-decorated zinc phosphates for synergistic alleviation of inflammatory bowel disease by repairing the mucosal barrier and relieving oxidative stress

Orally administered baicalein-decorated zinc phosphates (ZnBM) were engineered for mucosal barrier improvement and intestinal inflammation relief. ZnBM with a size of 1.78 μm comprised 5.58 wt% baicalein and 13.17 wt% zinc. The incorporation of baicalein endowed ZnBM with excellent radical scavenging activities. ZnBM exhibited good stability with negligible zinc release in PBS solution for 2 days, and 32.82% of the zinc could reach the gut. In addition, ZnBM polarized macrophages into the anti-inflammatory M2 type and effectively scavenged intracellular reactive oxygen species (ROS) of lipopolysaccharide (LPS)-treated RAW264.7. Meanwhile, ZnBM effectively scavenged intracellular ROS of phorbol 12-myristate 13-acetate (PMA)-induced Caco-2 cells and exerted a reparative effect on the LPS-damaged Caco-2 monolayer, causing an obvious improvement of the barrier function. Reduced systemic exposure to FITC-dextran was observed to illustrate barrier restoration by ZnBM, which was achieved through upregulation of tight junction protein expression. Notably, the commonly used clinical drug 5-aminosalicylic acid is toxic to the liver and kidneys, and commercial ZnO caused the death of mice during treatment. Apparently, the therapeutic effect of ZnBM was significantly better than that of baicalein alone in chronic colitis. Overall, ZnBM exhibited outstanding therapeutic efficacy and is expected to treat colitis due to its effectiveness, biosecurity, facile preparation, and easy storage.

Moringa oleifera Leaves Protein Enhances Intestinal Permeability by Activating TLR4 Upstream Signaling and Disrupting Tight Junctions

Changes in intestinal mucosal barrier permeability lead to antigen sensitization and mast cell-mediated allergic reactions, which are considered to play important roles in the occurrence and development of food allergies. It has been suggested that protein causes increased intestinal permeability via mast cell degranulation, and we investigated the effect of camellia Moringa oleifera leaves protein on intestinal permeability and explored its role in the development of food allergies. The current study investigated the effect of M. oleifera leaves protein on intestinal permeability through assessments of transepithelial electrical resistance (TEER) and transmembrane transport of FITC-dextran by Caco-2 cells. The expression levels of Toll-like receptor 4 (TLR4), IL-8, Occludin, Claudin-1, and perimembrane protein family (ZO-1) were detected by real-time PCR and Western blotting. The effect of M. oleifera leaves protein on intestinal permeability was verified in mice in vivo. The serum fluorescence intensity was measured using the FITC-dextran tracer method, and the expression of tight junction proteins was detected using Western blotting. The results showed that M. oleifera leaves protein widened the gaps between Caco-2 cells, reduced transmembrane resistance, and increased permeability. This protein also reduced the mRNA and protein levels of Occludin, Claudin-1, and ZO-1. Animal experiments showed that intestinal permeability was increased, and that the expression of the tight junction proteins Occludin and Claudin-1 were downregulated in mice. This study shows that M. oleifera leaves protein has components that increase intestinal permeability, decrease tight junction protein expression, promote transmembrane transport in Caco-2 cells, and increase intestinal permeability in experimental animals. The finding that M. oleifera leaves active protein increases intestinal permeability suggests that this protein may be valuable for the prevention, diagnosis, and treatment of M. oleifera leaves allergy.

CTRP6 regulates M1 macrophage polarization via the PPAR-γ/NF-κB pathway and reprogramming glycolysis in recurrent spontaneous abortion

Aberrant polarization and functions of decidual macrophages are closely related to recurrent spontaneous abortion (RSA). C1q/tumor necrosis factor-related protein 6 (CTRP6) is a member of the adiponectin paralog family, and plays indispensable roles in inflammation, glucose uptake and tumor metastasis. However, the regulatory effect of CTRP6 on macrophage polarization and glycolysis in RSA and the underlying mechanisms have not been fully elucidated. In the present study, we first found that CTRP6 expression was positively correlated with the M1 macrophage marker (CD86) in decidual tissues by dual immunofluorescence analysis. In vitro experiments indicated that CTRP6 could facilitate M1 macrophage activation through the PPAR-γ/NF-κB pathway and manipulate the glycolysis of macrophages. Notably, in addition to silencing CTRP6, treatment with a PPAR-γ agonist (GW1929) inhibited M1 macrophage polarization and rescued embryo absorption in vivo. Taken together, these results identify previously unrevealed functions of CTRP6 in macrophage transformation during RSA.

Colitis-associated carcinogenesis: crosstalk between tumors, immune cells and gut microbiota

Colorectal cancer (CRC) is the third most common cancer worldwide. One of the main causes of colorectal cancer is inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD). Intestinal epithelial cells (IECs), intestinal mesenchymal cells (IMCs), immune cells, and gut microbiota construct the main body of the colon and maintain colon homeostasis. In the development of colitis and colitis-associated carcinogenesis, the damage, disorder or excessive recruitment of different cells such as IECs, IMCs, immune cells and intestinal microbiota play different roles during these processes. This review aims to discuss the various roles of different cells and the crosstalk of these cells in transforming intestinal inflammation to cancer, which provides new therapeutic methods for chemotherapy, targeted therapy, immunotherapy and microbial therapy.

Spermidine Ameliorates Colitis via Induction of Anti-Inflammatory Macrophages and Prevention of Intestinal Dysbiosis

BACKGROUND AND AIMS

Exacerbated immune activation, intestinal dysbiosis and a disrupted intestinal barrier are common features among inflammatory bowel disease [IBD] patients. The polyamine spermidine, which is naturally present in all living organisms, is an integral component of the human diet, and exerts beneficial effects in human diseases. Here, we investigated whether spermidine treatment ameliorates intestinal inflammation and offers therapeutic potential for IBD treatment.

METHODS

We assessed the effect of oral spermidine administration on colitis severity in the T cell transfer colitis model in Rag2-/- mice by endoscopy, histology and analysis of markers of molecular inflammation. The effects on the intestinal microbiome were determined by 16S rDNA sequencing of mouse faeces. The impact on intestinal barrier integrity was evaluated in co-cultures of patient-derived macrophages with intestinal epithelial cells.

RESULTS

Spermidine administration protected mice from intestinal inflammation in a dose-dependent manner. While T helper cell subsets remained unaffected, spermidine promoted anti-inflammatory macrophages and prevented the microbiome shift from Firmicutes and Bacteroides to Proteobacteria, maintaining a healthy gut microbiome. Consistent with spermidine as a potent activator of the anti-inflammatory molecule protein tyrosine phosphatase non-receptor type 2 [PTPN2], its colitis-protective effect was dependent on PTPN2 in intestinal epithelial cells and in myeloid cells. The loss of PTPN2 in epithelial and myeloid cells, but not in T cells, abrogated the barrier-protective, anti-inflammatory effect of spermidine and prevented the anti-inflammatory polarization of macrophages.

CONCLUSION

Spermidine reduces intestinal inflammation by promoting anti-inflammatory macrophages, maintaining a healthy microbiome and preserving epithelial barrier integrity in a PTPN2-dependent manner.

The Role and Mechanism of Retinol and Its Transformation Product, Retinoic Acid, in Modulating Oxidative Stress-Induced Damage to the Duck Intestinal Epithelial Barrier In Vitro

This study aimed to investigate the effects and mechanisms of retinol and retinoic acid on primary duck intestinal epithelial cells under oxidative stress induced by H2O2. Different ratios of retinol and retinoic acid were used for treatment. The study evaluated the cell morphology, viability, antioxidative capacity, and barrier function of cells. The expression of genes related to oxidative stress and the intestinal barrier was analyzed. The main findings demonstrated that the treated duck intestinal epithelial cells exhibited increased viability, increased antioxidative capacity, and improved intestinal barrier function compared to the control group. High retinoic acid treatment improved viability and gene expression, while high retinol increased antioxidative indicators and promoted intestinal barrier repair. Transcriptome analysis revealed the effects of treatments on cytokine interactions, retinol metabolism, PPAR signaling, and cell adhesion. In conclusion, this study highlights the potential of retinol and retinoic acid in protecting and improving intestinal cell health under oxidative stress, providing valuable insights for future research.

Protein tyrosine phosphatase non-receptor type 2 as the therapeutic target of atherosclerotic diseases: past, present and future

Tyrosine-protein phosphatase non-receptor type 2(PTPN2), an important member of the protein tyrosine phosphatase family, can regulate various signaling pathways and biological processes by dephosphorylating receptor protein tyrosine kinases. Accumulating evidence has demonstrated that PTPN2 is involved in the occurrence and development of atherosclerotic cardiovascular disease. Recently, it has been reported that PTPN2 exerts an anti-atherosclerotic effect by regulating vascular endothelial injury, monocyte proliferation and migration, macrophage polarization, T cell polarization, autophagy, pyroptosis, and insulin resistance. In this review, we summarize the latest findings on the role of PTPN2 in the pathogenesis of atherosclerosis to provide a rationale for better future research and therapeutic interventions.

Targeting 14-3-3ζ by a small-molecule compound AI-34 maintains epithelial barrier integrity and alleviates colitis in mice via stabilizing β-catenin

Aberrant intestinal epithelial barrier function is the primary pathology of Ulcerative colitis (UC), making it a desirable drug target. In this study, our small-molecule compound AI-34 exerted a significant protective effect in an LPS-induced epithelial barrier injury model. In vitro, AI-34 treatment significantly decreased cell permeability, increased transmembrane resistance, and maintained the junctional protein (ZO-1 and E-cadherin) levels in monolayer cells. Using the LiP-small molecule mapping approach (LiP-SMap), we demonstrated that AI-34 binds to 14-3-3ζ. AI-34 promoted the interaction between 14-3-3ζ and β-catenin, decreasing the ubiquitination of β-catenin and thus maintaining intestinal epithelial barrier function. Finally, AI-34 triggered the stabilization of β-catenin mediated by 14-3-3ζ, provoking a significant improvement in the DSS-induced colitis model. Our findings suggest that AI-34 may be a promising candidate for UC treatment.

Limosilactobacillus johnsoni and Limosilactobacillus mucosae and Their Extracellular Vesicles Alleviate Gut Inflammatory Injury by Mediating Macrophage Polarization in a Lipopolysaccharide-Challenged Piglet Model

BACKGROUND

Limosilactobacillus johnsoni (L. j) and Limosilactobacillus mucosae (L. m) can alleviate the inflammatory response.

OBJECTIVES

This study aimed to elucidate the underlying mechanisms by which L. j- and L. m-derived extracellular vesicles (EVs) mitigate lipopolysaccharide (LPS)-induced intestinal injury.

METHODS

Piglets were assigned to 4 groups: oral phosphate-buffered saline inoculation for 2 wk prior to intraperitoneal injection of physiological saline or LPS, and oral L. j/L. m inoculation for 2 wk prior to intraperitoneal injection of LPS. The intestinal integrity, macrophage markers, cytokine levels, and microbiota were determined. The cytokine levels and macrophage phenotype were detected after L. j/L. m and their EVs were coincubated with macrophages. The levels of cytokines, tight junction proteins, and apoptosis were measured after intestinal epithelial cells were cocultured with macrophages.

RESULTS

LPS challenge decreased jejunal villus length; expression levels of zonula occludens-1 (ZO-1), occludin, arginase-1 (Arg1), and interleukin (IL)-10; and number of CD163+ cells and increased the expression levels of inducible nitric oxide synthase (iNOS), IL-1β, IL-6, and tumor necrosis factor (TNF)-α compared with that in the control. L. j and L. m pretreatment rescued the aforementioned indicators compared with LPS challenge. Pretreatment of L. j and L. m and their EVs reversed the levels of IL-1β, IL-6, TNF-α, and IL-10 and the gene expression of iNOS and Arg1 in the LPS group in macrophages. Pretreatment with L. j and L. m-derived EVs increased ZO-1 and occludin mRNA expression and reduced IL-1β, caspase-3, and bax gene expression in intestinal epithelial cells of the coculture system. Enzyme-treated EVs were less effective than native EVs.

CONCLUSIONS

This study suggests that EVs secreted by L. j and L. m control inflammation by modulating macrophage polarization, thereby improving intestinal barrier function.

Defining Interactions Between the Genome, Epigenome, and the Environment in Inflammatory Bowel Disease: Progress and Prospects

Recent advances in our understanding of the pathogenesis of inflammatory bowel disease (IBD) have highlighted the complex interplay between the genome, the epigenome, and the environment. Despite the exciting advances in genomics that have enabled the identification of over 200 susceptibility loci, these only account for a small proportion of the disease variance and the estimated heritability in IBD. It is likely that gene-environment (GxE) interactions contribute to "missing heritability" and these may act through epigenetic mechanisms. Several environmental factors, such as the microbiome, nutrition, and tobacco smoking, induce alterations in the epigenome of children and adults, which may impact disease susceptibility. Other mechanisms for GxE interactions are also directly pertinent in early life. We discuss a model in which environmental factors imprint disease risk in a window of susceptibility during infancy that may contribute to later disease onset, whereas other elements of the exposome act later in life and contribute directly to the pathogenesis and course of the disease. Understanding the mechanisms underlying GxE interactions may provide the basis for new therapeutic targets or preventative strategies for IBD.

Supplementing Genistein for Breeder Hens Alters the Growth Performance and Intestinal Health of Offspring

Recent research revealed that dietary genistein supplementation for breeder hens can improve the immune function of offspring chicks. However, it remains unknown whether this maternal effect could improve the intestinal health of offspring. This study was conducted to explore the mechanism involved in the maternal effect of genistein on the intestinal mucosa and microbial homeostasis of chicken offspring. A total of 120 Qiling breeder hens were fed a basal diet, a 20 mg/kg genistein-supplemented diet, or a 40 mg/kg genistein-supplemented diet for 4 weeks before collecting their eggs. After hatching, 180 male offspring (60 chickens from each group) were randomly selected and divided into three groups: (1) the offspring of hens fed a basal diet (CON); (2) the offspring of hens fed a low-dose genistein-supplemented diet (LGE); (3) the offspring of hens fed a high-dose genistein-supplemented diet (HGE). At 17 d, 72 male offspring (48 chickens from CON and 24 chickens from LGE) were divided into three groups: (1) the offspring of hens fed a basal diet (CON); (2) the CON group challenged with LPS (LPS); (3) the LGE group challenged with LPS (LPS + LGE). The results showed that maternal genistein supplementation increased the birth weight and serum level of total protein (TP), followed by improved intestinal villus morphology. Continuously, the maternal effect on the body weight of chicks lasted until 21 d. Additionally, it was observed that maternal genistein supplementation exhibited protective effects against LPS-induced morphological damage and intestinal mucosal barrier dysfunction by upregulating the expression of tight junction proteins, specifically ZO-1, Claudin1, E-cadherin, and Occludin, at 21 d. Using 16S rRNA gene sequencing, we demonstrated that maternal supplementation of genistein has the potential to facilitate the maturation of newly hatched chicken offspring by enhancing the abundance of Escherichia coli. Additionally, maternal genistein supplementation can effectively reduce the abundance of Gammaproteobacteria, thus mitigating the risk of bacterial diversity impairment of LPS. In light of these findings, maternal genistein supplementation holds promise as a potential strategy for ameliorating intestinal mucosal damage and modulating the microbiome in chicken offspring.

Spermidine protects intestinal mucosal barrier function in mice colitis via the AhR/Nrf2 and AhR/STAT3 signaling pathways

BACKGROUND

Aryl hydrocarbon receptor (AhR) activation promotes intestinal barrier repair and enhances the gut mucosal barrier function in inflammatory bowel diseases (IBD). Spermidine is beneficial in several murine models of IBD and may affect AhR activity. However, the precise effects of spermidine on the intestinal barrier and AhR remain unclear. This study was designed to investigate whether spermidine affects AhR and gut barrier function in IBD models as well as, its underlying mechanism.

METHODS

We used dextran sulfate sodium (DSS)- and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced mice, as well as, Caco2 cells incubated with TNF-α and IFN-γ to establish multiple IBD models, followed by spermidine intervention. Alcian blue/Periodic acid-Schiff (AB/PAS) staining, Fluorescein isothiocyanate (FITC)-dextran permeability assay, transepithelial electrical resistance (TER), tight junction protein (TJs) expression, and 16S rRNA scope in situ hybridization were performed to assess intestinal barrier function. AhR expression and the associated pathways were measured. AhR-targeted adeno-associated virus (AAV) and siRNA were used to explore the related molecular mechanisms.

RESULTS

Spermidine significantly attenuated the increased intestinal permeability, decreased TER, abnormal distribution of TJs in colitis, and bacterial translocation from the gut tract. Additionally, it significantly increased AhR and Nrf2 expression and inhibited STAT3 phosphorylation. However, the protective effects of spermidine and the related alterations in pathway proteins were largely abolished by the specific inhibition of AhR.

CONCLUSION

Our study demonstrated that spermidine rescues intestinal barrier defects in mice with colitis via the AhR-Nrf2 and AhR-STAT3 pathways, providing a potential therapeutic agent for IBD and other conditions associated with dysregulated gut barrier function.

Pro-inflammatory Polarization of Macrophages Causes Intestinal Inflammation in Low-Birth-Weight Piglets and Mice

BACKGROUND

Low-birth-weight (LBW) animals suffer from intestinal damage and inflammation in their early life.

OBJECTIVES

The aim of this study was to investigate the role of macrophages in intestinal inflammation in LBW piglets and mice.

METHODS

Major genes involved in intestinal barrier function such as claudin-1, zonula occludens-1 (ZO-1), occludin, and mucin 2 and inflammatory cytokines such as IL-1β, TNF-α, IL-10, and IL-13 were evaluated in 21-day-old, normal birth weight (NBW) and LBW piglets and mice. Macrophage markers such as CD16/32, CD163, and CD206 were also assessed by immunofluorescence and flow cytometry. Polarized and unpolarized macrophages were further transferred into NBW and LBW mice, followed by evaluation of intestinal permeability and inflammation.

RESULTS

Claudin-1 mRNA in LBW piglets as well as claudin-1, occludin, ZO-1 and mucin 2 mRNAs in LBW mice was significantly downregulated. IL-1β and TNF-α were significantly upregulated in LBW piglets (P < 0.05). LBW mice showed a reduced expression of IL-10 and IL-13 (P < 0.05), with a heightened IL-6 level (P < 0.01) in the jejunum. CD16, a marker for M1 macrophages, was significantly elevated in the jejunum of LBW piglets, whereas CD163, a marker for M2 macrophages, was significantly decreased (P < 0.05). Similarly, LBW mice had more CD11b+CD16/32+ M1 macrophages (P < 0.05) and fewer CD206+ M2 macrophages (P < 0.01) than NBW mice. Moreover, transfer of M1 macrophages exacerbated intestinal inflammation in LBW mice. Furthermore, two major glycolysis-associated genes, hexokinase 2 (HK2) and lactate dehydrogenase A (LDHA), were significantly upregulated in LBW piglets and mice (P < 0.05).

CONCLUSIONS

This study revealed for the first time that the intestinal macrophages are polarized towards a pro-inflammatory phenotype in LBW piglets and mice, contributing to intestinal inflammation. The findings of this study provide new options for the management of intestinal inflammation in LBW animals.

Hypoxia disrupts the nasal epithelial barrier by inhibiting PTPN2 in chronic rhinosinusitis with nasal polyps

BACKGROUND

Hypoxia is involved in inflammation and immune response; however, its role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) is not fully understood. We aimed to investigate the mechanisms by which hypoxia disrupts the nasal epithelial barrier in CRSwNP.

METHODS

The expression of hypoxia-inducible factor-1α (HIF-1α), protein tyrosine phosphatase non-receptor type 2 (PTPN2), and tight junction (TJ) components (claudin-4, occludin, and ZO-1) was detected in nasal polyps using immunohistochemistry, western blotting, and qRT-PCR. Primary human nasal epithelial cells (HNECs), BEAS-2B cells, and an eosinophilic CRSwNP (Eos CRSwNP) mouse model were used to explore the potential mechanisms by which hypoxia disrupts the nasal epithelial barrier.

RESULTS

HIF-1α expression in the non-Eos and Eos CRSwNP groups was higher than in the control group, and the expression of PTPN2 and TJs in the non-Eos and Eos CRSwNP groups were lower than those in the control group. Hypoxia decreased the expression of PTPN2 and TJs and increased epithelial cell permeability in HNECs, which was blocked by the HIF-1α inhibitor PX-478. PTPN2 overexpression inhibited hypoxia-induced downregulation of TJ expression in BEAS-2B cells, whereas PTPN2-knockdown aggravated the effects of hypoxia. In the Eos CRSwNP mouse model, both PX-478 and PTPN2 overexpression reduced the formation of nasal polypoid lesions, permeability of the nasal epithelium, and restored TJ expression.

CONCLUSIONS

Our data indicate that hypoxia-induced HIF-1α downregulates TJ expression by inhibiting PTPN2, thereby disrupting the nasal epithelial barrier and promoting CRSwNP development. HIF-1α and PTPN2 may be potential targets for the treatment of CRSwNP.

Epithelial Gab1 calibrates RIPK3-dependent necroptosis to prevent intestinal inflammation

As a hallmark of inflammatory bowel disease (IBD), elevated intestinal epithelial cell (IEC) death compromises the gut barrier, activating the inflammatory response and triggering more IEC death. However, the precise intracellular machinery that prevents IEC death and breaks this vicious feedback cycle remains largely unknown. Here, we report that Grb2-associated binder 1 (Gab1) expression is decreased in patients with IBD and inversely correlated with IBD severity. Gab1 deficiency in IECs accounted for the exacerbated colitis induced by dextran sodium sulfate owing to sensitizing IECs to receptor-interaction protein kinase 3-mediated (RIPK3-mediated) necroptosis, which irreversibly disrupted the homeostasis of the epithelial barrier and promoted intestinal inflammation. Mechanistically, Gab1 negatively regulated necroptosis signaling through inhibiting the formation of RIPK1/RIPK3 complex in response to TNF-α. Importantly, administration of RIPK3 inhibitor revealed a curative effect in epithelial Gab1-deficient mice. Further analysis indicated mice with Gab1 deletion were prone to inflammation-associated colorectal tumorigenesis. Collectively, our study defines a protective role for Gab1 in colitis and colitis-driven colorectal cancer by negatively regulating RIPK3-dependent necroptosis, which may serve as an important target to address necroptosis and intestinal inflammation-related disease.

The role of endoplasmic reticulum stress in regulation of intestinal barrier and inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease involving the digestive tract, characterized by abdominal pain, diarrhea, rectal bleeding, and so on, which can make patients physically weakened and live difficultly. Although IBD has been recognized for many years, the pathogenesis of IBD has not yet been established and damage to intestinal barrier is thought to be closely associated with IBD. Intestinal barrier is an innate barrier that maintains the homeostasis of the intestinal environment and impedes pathogenic bacteria and toxins, and the endoplasmic reticulum (ER) has recently been found to be involved in maintaining the integrity of intestinal barrier. Endoplasmic reticulum stress (ERS) is a status of endoplasmic reticulum damaged when unfolded or misfolded proteins accumulate in excess of the degradation systematic clearance limit of the misfolded proteins. The regulation of ERS on protein folding synthesis and maintenance of cellular homeostasis is an important factor in influencing the integrity of the intestinal barrier. This paper mainly discusses the relationship between ERS and the intestinal barrier, aiming to understand the regulatory role of ERS on the intestinal barrier and the mechanism and to improve new solutions and notions for the treatment or prevention of IBD.

PTPN2 regulates bacterial clearance in a mouse model of enteropathogenic and enterohemorrhagic E. coli infection

Macrophages intimately interact with intestinal epithelial cells, but the consequences of defective macrophage-epithelial cell interactions for protection against enteric pathogens are poorly understood. Here, we show that in mice with a deletion in protein tyrosine phosphatase nonreceptor type 2 (PTPN2) in macrophages, infection with Citrobacter rodentium, a model of enteropathogenic and enterohemorrhagic E. coli infection in humans, promoted a strong type 1/IL-22-driven immune response, culminating in accelerated disease but also faster clearance of the pathogen. In contrast, deletion of PTPN2 specifically in epithelial cells rendered the epithelium unable to upregulate antimicrobial peptides and consequently resulted in a failure to eliminate the infection. The ability of PTPN2-deficient macrophages to induce faster recovery from C. rodentium was dependent on macrophage-intrinsic IL-22 production, which was highly increased in macrophages deficient in PTPN2. Our findings demonstrate the importance of macrophage-mediated factors, and especially macrophage-derived IL-22, for the induction of protective immune responses in the intestinal epithelium, and show that normal PTPN2 expression in the epithelium is crucial to allow for protection against enterohemorrhagic E. coli and other intestinal pathogens.

Targeting protein phosphatases in cancer immunotherapy and autoimmune disorders

Protein phosphatases act as key regulators of multiple important cellular processes and are attractive therapeutic targets for various diseases. Although extensive effort has been dedicated to phosphatase-targeted drug discovery, early expeditions for competitive phosphatase inhibitors were plagued by druggability issues, leading to the stigmatization of phosphatases as difficult targets. Despite challenges, persistent efforts have led to the identification of several drug-like, non-competitive modulators of some of these enzymes - including SH2 domain-containing protein tyrosine phosphatase 2, protein tyrosine phosphatase 1B, vascular endothelial protein tyrosine phosphatase and protein phosphatase 1 - reigniting interest in therapeutic targeting of phosphatases. Here, we discuss recent progress in phosphatase drug discovery, with emphasis on the development of selective modulators that exhibit biological activity. The roles and regulation of protein phosphatases in immune cells and their potential as powerful targets for immuno-oncology and autoimmunity indications are assessed.

Protective Mechanism of Ethyl Gallate against Intestinal Ischemia-Reperfusion Injury in Mice by in Vivo and in Vitro Studies Based on Transcriptomics

Intestinal ischemia-reperfusion injury (IIRI) is a common clinical disease that can be life-threatening in severe cases. This study aimed to investigate the effects of ethyl gallate (EG) on IIRI and its underlying mechanisms. A mouse model was established to mimic human IIRI by clamping the superior mesenteric artery. Transcriptomics techniques were used in conjunction with experiments to explore the potential mechanisms of EG action. Intestinal histomorphological damage, including intestinal villi damage and mucosal hemorrhage, was significantly reversed by EG. EG also alleviated the oxidative stress, inflammation, and intestinal epithelial apoptosis caused by IIRI. 2592 up-regulated genes and 2754 down-regulated genes were identified after EG treatment, and these differential genes were enriched in signaling pathways, including fat digestion and absorption, and extracellular matrix (ECM) receptor interactions. In IIRI mouse intestinal tissue, expression of the differential protein matrix metalloproteinase 9 (MMP9), as well as its co-protein NF-κB-p65, was significantly increased, while EG inhibited the expression of MMP9 and NF-κB-p65. In Caco-2 cells in an established oxygen-glucose deprivation/reperfusion model (OGD/R), EG significantly reversed the decrease in intestinal barrier trans-epithelial electrical resistance (TEER). However, in the presence of MMP9 inhibitors, EG did not reverse the decreasing trend in TEER. This study illustrates the protective effect and mechanism of action of EG on IIRI and, combined with in vivo and in vitro experiments, it reveals that MMP9 may be the main target of EG action. This study provides new scientific information on the therapeutic effects of EG on IIRI.

Small extracellular vesicles from Ptpn1-deficient macrophages alleviate intestinal inflammation by reprogramming macrophage polarization via lactadherin enrichment

Tyrosine-protein phosphatase non-receptor type 1 (Ptpn1) is known to be involved in macrophage polarization. However, whether and how Ptpn1 regulates macrophage phenotype to affect intestinal epithelial barrier function remains largely unexplored. Herein, we investigated the impact of Ptpn1 and macrophage-derived small extracellular vesicles (sEVs) on macrophage-intestinal epithelial cell (IEC) interactions in the context of intestinal inflammation. We found that Ptpn1 knockdown shifts macrophages toward the anti-inflammatory M2 phenotype, thereby promoting intestinal barrier integrity and suppressing inflammatory response in the macrophage-IEC co-culture model. We further revealed that conditioned medium or sEVs isolated from Ptp1b knockdown macrophages are the primary factor driving the beneficial outcomes. Consistently, administration of the sEVs from Ptpn1-knockdown macrophages reduced disease severity and ameliorated intestinal inflammation in LPS-challenged mice. Furthermore, depletion of macrophages in mice abrogated the protective effect of Ptpn1-knockdown macrophage sEVs against Salmonella Typhimurium infection. Importantly, we found lactadherin to be highly enriched in the sEVs of Ptpn1-knockdown macrophages. Administration of recombinant lactadherin alleviated intestinal inflammation and barrier dysfunction by inducing macrophage M2 polarization. Interestingly, sEVs lactadherin was also internalized by macrophages and IECs, leading to macrophage M2 polarization and enhanced intestinal barrier integrity. Mechanistically, the anti-inflammatory and barrier-enhancing effect of lactadherin was achieved by reducing TNF-α and NF-κB activation. Thus, we demonstrated that sEVs from Ptpn1-knockdown macrophages mediate the communication between IECs and macrophages through enrichment of lactadherin. The outcome could potentially lead to the development of novel therapies for intestinal inflammatory disorders.

Vindoline ameliorates intestinal barrier damage in Crohn's disease mice through MAPK signaling pathway

Intestinal inflammation and intestinal barrier damage are important pathological changes in Crohn's disease (CD). Vindoline is a natural monomer with anti-inflammatory effects. We employed CD model mice to explore the effect of Vindoline on CD-like colitis and the possible mechanism. Il-10-deficient (Il-10^-/- ) mice and wild-type (WT) mice (both aged 15 weeks, male) were used to explore the effect of Vindoline on colitis and intestinal barrier damage, as well as macrophage-mediated inflammation. Bone-marrow-derived macrophages (BMDMs) and colonic organoids from mice were used to explore the inhibitory effect of Vindoline on macrophage-mediated inflammation and the protective effect on inflammation-induced intestinal barrier damage as well as the possible mechanism. We found that Vindoline significantly ameliorated colitis in CD mice, as evidenced by increased weight change and colon length and decreased the colon macroscopic injury score, histological inflammatory score, and the expression of pro-inflammatory mediators. Vindoline also protected against intestinal barrier damage in CD mice. Furthermore, Vindoline inhibited macrophage-mediated inflammation and protected against inflammation-induced intestinal barrier damage in the coculture system. In addition, Vindoline ameliorated colitis in CD mice by protecting against inflammation-induced intestinal barrier damage, which may be caused by inhibition of MAPK signaling pathway. This protective effect suggests that Vindoline has potential value for clinical application in the treatment of CD.