Chang'an decoction alleviates endoplasmic reticulum stress by regulating mitofusin 2 to improve colitis.

OBJECTIVE: To evaluate the protective effects of Chang'an decoction (, CAD) on colitis, and investigate the potential mechanisms underlying these effects from the perspectives of endoplasmic reticulum (ER) stress induced by mitofusin 2 (MFN2). METHODS: The composition of CAD was identified by liquid chromatography-mass spectrometry technology. A mice model of dextran sulfate sodium (DSS) induced colitis was established and therapeutic effects of CAD were determined by detecting body weight, disease activity index, colon length and histopathological changes. Then, the expression levels of MFN2, ER stress markers and Nucleotide-binding domain and leucine-rich repeat protein3 (NLRP3) relevant proteins were detected by polymerase chain reaction (PCR), Western blot, immunohistochemistry and immunofluorescence staining. Subsequently, knockdown and overexpression cell model were constructed to further investigate the underlying mechanism of MFN2 mediating ER stress and energy metabolism by PCR, Western blot, electron microscopy and reactive oxygen species (ROS) staining. Finally, inflammatory indicator and tight junction proteins were measured by PCR and immunofluorescence staining to evaluate the protective effects of CAD. RESULTS: Results showed that the indispensable regulatory role of MFN2 in mediating ER stress and mitochondrial damage was involved in the protective effects of CAD on colitis in mice fed with DSS. Network pharmacology analysis also revealed CAD may play a protective effect on colitis by affecting mitochondrial function. In addition, our data also suggested a causative role for MFN2 in the development of inflammatory responses and energy metabolic alterations by constructing a knockdown and overexpression cell model whereby alter proper ER-mitochondria interaction in Caco-2 cells. Furthermore, relative expression analyses of ER stress markers and NLRP3 inflammasome showed the onset of ER stress and activation of NLRP3 inflammasome, which is consistent with the above findings. In contrast, intervention of CAD could improve the mucosal barrier integrity and colonic inflammatory response effectively through inhibiting ER stress response mediated by MFN2. CONCLUSION: CAD could alleviate ER stress by regulating MFN2 to exert therapeutic effects on DSS-induced colitis, which might provide an effective natural therapeutic approach for the treatment of ulcerative colitis.

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

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

Complanatuside A ameliorates 2,4,6-trinitrobenzene sulfonic acid-induced colitis in mice by regulating the Th17/Treg balance via the JAK2/STAT3 signaling pathway.

Immunity imbalance of T helper 17 (Th17)/regulatory T (Treg) cells is involved in the pathogenesis of Crohn's disease (CD). Complanatuside A (CA), a flavonol glycoside, exerts anti-inflammatory activities and our study aimed to identify its effect on TNBS-induced colitis and the possible mechanisms. We found that CA alleviated the symptoms of colitis in TNBS mice, as demonstrated by prevented weight loss and colon length shortening, as well as decreased disease activity index scores, inflammatory scores, and levels of proinflammatory factors. Flow cytometry analysis showed that CA markedly reduced the percentage of Th17 cells while increasing the percentage of Treg cells in TNBS mice. Under Th17 cell polarizing conditions, CA inhibited the differentiation of Th17 cells while the Treg cell differentiation was elevated under Treg cell polarizing conditions. Furthermore, it was observed that JAK2 interacted with CA through six hydrogen bonds via molecular docking. The phosphorylation of JAK2/STAT3 was reduced by CA, which might be correlated with the protective effect of CA on colitis. In conclusion, CA reduced the imbalance of Th17/Treg cells by inhibiting the JAK2/STAT3 signaling pathway in TNBS-induced colitis, which may provide novel strategies for CD treatment.

The gut lactic acid bacteria metabolite, 10-oxo-cis-6,trans-11-octadecadienoic acid, suppresses inflammatory bowel disease in mice by modulating the NRF2 pathway and GPCR-signaling.

Various gut bacteria, including Lactobacillus plantarum, possess several enzymes that produce hydroxy fatty acids (FAs), oxo FAs, conjugated FAs, and partially saturated FAs from polyunsaturated FAs as secondary metabolites. Among these derivatives, we identified 10-oxo-cis-6,trans-11-octadecadienoic acid (γKetoC), a γ-linolenic acid (GLA)-derived enon FA, as the most effective immunomodulator, which inhibited the antigen-induced immunoactivation and LPS-induced production of inflammatory cytokines. The treatment with γKetoC significantly suppressed proliferation of CD4+ T cells, LPS-induced activation of bone marrow-derived dendritic cells (BMDCs), and LPS-induced IL-6 release from peritoneal cells, splenocytes, and CD11c+ cells isolated from the spleen. γKetoC also inhibited the release of inflammatory cytokines from BMDCs stimulated with poly-I:C, R-848, or CpG. Further in vitro experiments using an agonist of GPR40/120 suggested the involvement of these GPCRs in the effects of γKetoC on DCs. We also found that γKetoC stimulated the NRF2 pathway in DCs, and the suppressive effects of γKetoC and agonist of GPR40/120 on the release of IL-6 and IL-12 were reduced in Nrf2-/- BMDCs. We evaluated the role of NRF2 in the anti-inflammatory effects of γKetoC in a dextran sodium sulfate-induced colitis model. The oral administration of γKetoC significantly reduced body weight loss, improved stool scores, and attenuated atrophy of the colon, in wild-type C57BL/6 and Nrf2+/- mice with colitis. In contrast, the pathology of colitis was deteriorated in Nrf2-/- mice even with the administration of γKetoC. Collectively, the present results demonstrated the involvement of the NRF2 pathway and GPCRs in γKetoC-mediated anti-inflammatory responses.

[Upregulating KLF11 ameliorates intestinal inflammation in mice with 2, 4, 6-trinitrobenesulfonic acid-induced colitis by inhibiting the JAK2/STAT3 signaling pathway].

OBJECTIVE: To investigate the expression level of Kruppel-like transcription factor family member KLF11 in intestinal mucosal tissues of Crohn's disease (CD) and its regulatory effect on intestinal inflammation in CD-like colitis. METHODS: We examined KLF11 expression levels in diseased and normal colon mucosal tissues from 12 CD patients and 12 patients with colorectal cancer using immunofluorescence staining. KLF11 expression was also detected in the colon mucosal tissues of a mouse model of 2, 4, 6-trinitrobenesulfonic acid (TNBS)-induced colitis. A recombinant adenoviral vector was used to upregulate KLF11 expression in the mouse models and the changes in intestinal inflammation was observed. A Caco-2 cell model with stable KLF11 overexpression was constructed by lentiviral infection. The effect of KLF11 overexpression on expressions of JAK2/STAT3 signaling pathway proteins was investigated using immunoblotting in both the mouse and cell models. The mouse models were treated with coumermycin A1, a JAK2/STAT3 signaling pathway agonist, and the changes in intestinal inflammatory responses were observed. RESULTS: The expression level of KLF11 was significantly lowered in both the clinical specimens of diseased colon mucosal tissues and the colon tissues of mice with TNBS-induced colitis (P < 0.05). Adenovirus-mediated upregulation of KLF11 significantly improved intestinal inflammation and reduced the expression levels of inflammatory factors in the intestinal mucosa of the colitis mouse models (P < 0.05). Overexpression of KLF11 significantly inhibited the expression levels of p-JAK2 and p-STAT3 in intestinal mucosal tissues of the mouse models and in Caco-2 cells (P < 0.05). Treatment with coumermycin A1 obviously inhibited the effect of KLF11 upregulation for improving colitis and significantly increased the expression levels of inflammatory factors in the intestinal mucosa of the mouse models (P < 0.05). CONCLUSION: KLF11 is downregulated in the intestinal mucosa in CD, and upregulation of KLF11 can improve intestinal inflammation and reduce the production of inflammatory factors probably by inhibiting the JAK2/STAT3 signaling pathway.

Lactobacillus delbrueckii CIDCA 133 fermented milk modulates inflammation and gut microbiota to alleviate acute colitis.

Lactobacillus delbrueckii subsp. lactis CIDCA 133 is a health-promoting bacterium that can alleviate gut inflammation and improve the epithelial barrier in a mouse model of mucositis. Despite these beneficial effects, the protective potential of this strain in other inflammation models, such as inflammatory bowel disease, remains unexplored. Herein, we examined for the first time the efficacy of Lactobacillus delbrueckii CIDCA 133 incorporated into a fermented milk formulation in the recovery of inflammation, epithelial damage, and restoration of gut microbiota in mice with dextran sulfate sodium-induced colitis. Oral administration of Lactobacillus delbrueckii CIDCA 133 fermented milk relieved colitis by decreasing levels of inflammatory factors (myeloperoxidase, N-acetyl-ß-D-glucosaminidase, toll-like receptor 2, nuclear factor-κB, interleukins 10 and 6, and tumor necrosis factor), secretory immunoglobulin A levels, and intestinal paracellular permeability. This immunobiotic also modulated the expression of tight junction proteins (zonulin and occludin) and the activation of short-chain fatty acids-related receptors (G-protein coupled receptors 43 and 109A). Colonic protection was effectively associated with acetate production and restoration of gut microbiota composition. Treatment with Lactobacillus delbrueckii CIDCA 133 fermented milk increased the abundance of Firmicutes members (Lactobacillus genus) while decreasing the abundance of Proteobacteria (Helicobacter genus) and Bacteroidetes members (Bacteroides genus). These promising outcomes influenced the mice's mucosal healing, colon length, body weight, and disease activity index, demonstrating that this immunobiotic could be explored as an alternative approach for managing inflammatory bowel disease.

E4BP4 in macrophages induces an anti-inflammatory phenotype that ameliorates the severity of colitis.

Macrophages are versatile cells of the innate immune system that work by altering their pro- or anti-inflammatory features. Their dysregulation leads to inflammatory disorders such as inflammatory bowel disease. We show that macrophage-specific upregulation of the clock output gene and transcription factor E4BP4 reduces the severity of colitis in mice. RNA-sequencing and single-cell analyses of macrophages revealed that increased expression of E4BP4 leads to an overall increase in expression of anti-inflammatory genes including Il4ra with a concomitant reduction in pro-inflammatory gene expression. In contrast, knockout of E4BP4 in macrophages leads to increased proinflammatory gene expression and decreased expression of anti-inflammatory genes. ChIP-seq and ATAC-seq analyses further identified Il4ra as a target of E4BP4, which drives anti-inflammatory polarization in macrophages. Together, these results reveal a critical role for E4BP4 in regulating macrophage inflammatory phenotypes and resolving inflammatory bowel diseases.

Anxiolytic effects of Enterococcus faecalis 2001 on a mouse model of colitis.

Ulcerative colitis (UC) is a refractory inflammatory bowel disease, which is known to cause psychiatric disorders such as anxiety and depression at a high rate in addition to peripheral inflammatory symptoms. However, the pathogenesis of these psychiatric disorders remains mostly unknown. While prior research revealed that the Enterococcus faecalis 2001 (EF-2001) suppressed UC-like symptoms and accompanying depressive-like behaviors, observed in a UC model using dextran sulfate sodium (DSS), whether it has an anxiolytic effect remains unclear. Therefore, we examined whether EF-2001 attenuates DSS-induced anxiety-like behaviors. Treatment with 2% DSS for seven days induced UC-like symptoms and anxiety-like behavior through the hole-board test, increased serum lipopolysaccharide (LPS) and corticosterone concentration, and p-glucocorticoid receptor (GR) in the prefrontal cortex (PFC), and decreased N-methyl-D-aspartate receptor subunit (NR) 2A and NR2B expression levels in the PFC. Interestingly, these changes were reversed by EF-2001 administration. Further, EF-2001 administration enhanced CAMKII/CREB/BDNF-Drebrin pathways in the PFC of DSS-treated mice, and labeling of p-GR, p-CAMKII, and p-CREB showed colocalization with neurons. EF-2001 attenuated anxiety-like behavior by reducing serum LPS and corticosterone levels linked to the improvement of UC symptoms and by facilitating the CAMKII/CREB/BDNF-Drebrin pathways in the PFC. Our findings suggest a close relationship between UC and anxiety.

Taenia solium cysticerci's extracellular vesicles Attenuate the AKT/mTORC1 pathway for Alleviating DSS-induced colitis in a murine model.

The excretory-secretory proteome plays a pivotal role in both intercellular communication during disease progression and immune escape mechanisms of various pathogens including cestode parasites like Taenia solium. The cysticerci of T. solium causes infection in the central nervous system known as neurocysticercosis (NCC), which affects a significant population in developing countries. Extracellular vesicles (EVs) are 30-150-nm-sized particles and constitute a significant part of the secretome. However, the role of EV in NCC pathogenesis remains undetermined. Here, for the first time, we report that EV from T. solium larvae is abundant in metabolites that can negatively regulate PI3K/AKT pathway, efficiently internalized by macrophages to induce AKT and mTOR degradation through auto-lysosomal route with a prominent increase in the ubiquitination of both proteins. This results in less ROS production and diminished bacterial killing capability among EV-treated macrophages. Due to this, both macro-autophagy and caspase-linked apoptosis are upregulated, with a reduction of the autophagy substrate sequestome 1. In summary, we report that T. solium EV from viable cysts attenuates the AKT-mTOR pathway thereby promoting apoptosis in macrophages, and this may exert immunosuppression during an early viable stage of the parasite in NCC, which is primarily asymptomatic. Further investigation on EV-mediated immune suppression revealed that the EV can protect the mice from DSS-induced colitis and improve colon architecture. These findings shed light on the previously unknown role of T. solium EV and the therapeutic role of their immune suppression potential.

The comparative anti-oxidant and anti-inflammatory efficacy of postbiotics and probiotics through Nrf-2 and NF-kB pathways in DSS-induced colitis model.

IBD is a disorder which could be caused by oxidative stress. This investigation aims to determine if probiotics and postbiotics can control oxidative stress and inflammation and compare the effectiveness of these two probiotic and postbiotic mixtures of substances. 88 strains of Lactobacillus and Bifidobacterium were tested for antioxidant activity. Male wild-type C57BL/6 mice were divided into four experimental groups, namely high fat diet (HFD) + PBS, HFD + DSS, HFD + DSS + 109 cfu/ml of probiotics, and HFD + DSS + 109 cfu/ml of postbiotics. The phenotypical indices and pathological scores were assessed. The expression of genes related to NF-kB and Nrf2 signaling pathways and enzymes associated with oxidant/anti-oxidant activities, and proinflammatory/inflammatory cytokines were assessed. In contrast to the groups exposed to DSS, mice treated with probiotics mixture and postbiotics mixture alongside DSS displayed alleviation of DSS-induced adverse effects on phenotypical characteristics, as well as molecular indices such as the Nrf2 and NF-kB related genes, with a greater emphasis on the postbiotics component. In accordance with the findings of the present investigation, it can be inferred that even in using a high-fat dietary regimen as an inducer of oxidative stress, the emergence of inflammation can be effectively addressed through the utilization of probiotics and, more specifically, postbiotics.

Anti-inflammatory and protective effects of Aripiprazole on TNBS-Induced colitis and associated depression in rats: Role of kynurenine pathway.

BACKGROUND: The prevalence of depression is higher in patients with inflammatory bowel disease (IBD) than in the general population. Inflammatory cytokines and the kynurenine pathway (KP) play important roles in IBD and associated depression. Aripiprazole (ARP), an atypical antipsychotic, shows various anti-inflammatory properties and may be useful in treating major depressive disorder. This study aimed to evaluate the protective effects of ARP on TNBS-induced colitis and subsequent depression in rats, highlighting the role of the KP. MATERIAL AND METHODS: Fifty-six male Wistar rats were used, and all groups except for the normal and sham groups received a single dose of intra-rectal TNBS. Three different doses of ARP and dexamethasone were injected intraperitoneally for two weeks in treatment groups. On the 15th day, behavioral tests were performed to evaluate depressive-like behaviors. Colon ulcer index and histological changes were assessed. The tissue levels of inflammatory cytokines, KP markers, lipopolysaccharide (LPS), nuclear factor-kappa-B (NF-κB), and zonula occludens (ZO-1) were evaluated in the colon and hippocampus. RESULTS: TNBS effectively induced intestinal damages and subsequent depressive-like symptoms in rats. TNBS treatment significantly elevated the intestinal content of inflammatory cytokines and NF-κB expression, dysregulated the KP markers balance in both colon and hippocampus tissues, and increased the serum levels of LPS. However, treatment with ARP for 14 days successfully reversed these alterations, particularly at higher doses. CONCLUSION: ARP could alleviate IBD-induced colon damage and associated depressive-like behaviors mainly via suppressing inflammatory cytokines activity, serum LPS concentration, and affecting the NF-κB/kynurenine pathway.

The Role of TRP Channels in Sepsis and Colitis.

To date, several members of the transient receptor potential (TRP) channels which provide a wide array of roles have been found in the gastrointestinal tract (GI). The goal of earlier research was to comprehend the intricate signaling cascades that contribute to TRP channel activation as well as how these receptors' activity affects other systems. Moreover, there is a large volume of published studies describing the role of TRP channels in a number of pathological disorders, including inflammatory bowel disease (IBD) and sepsis. Nevertheless, the generalizability of these results is subject to certain limitations. For instance, the study of IBD relies on various animal models and experimental methods, which are unable to precisely imitate the multifactorial chronic disease. The diverse pathophysiological mechanisms and unique susceptibility of animals may account for the inconsistency of the experimental data collected. The main purpose of this study was to conduct a comprehensive review and analysis of existing studies on transient receptor potential (TRP) channels implicating specific models of colitis and sepsis, with particular emphasis on their involvement in pathological disorders such as IBD and sepsis. Furthermore, the text endeavors to evaluate the generalizability of experimental findings, taking into consideration the limitations posed by animal models and experimental methodologies. Finally, we also provide an updated schematic of the most important and possible molecular signaling pathways associated with TRP channels in IBD and sepsis.

Bone marrow mesenchymal stromal cells support regeneration of intestinal damage in a colitis mouse model, independent of their CXCR4 expression.

Inflammatory bowel disease (IBD) is characterized by a chronically dysregulated immune response in the gastrointestinal tract. Bone marrow multipotent mesenchymal stromal cells have an important immunomodulatory function and support regeneration of inflamed tissue by secretion of soluble factors as well as through direct local differentiation. CXCR4 is the receptor for CXCL12 (SDF-1, stromal-derived factor-1) and has been shown to be the main chemokine receptor, required for homing of MSCs. Increased expression of CXCL12 by inflamed intestinal tissue causes constitutive inflammation by attracting lymphocytes but can also be used to direct MSCs to sites of injury/inflammation. Trypsin is typically used to dissociate MSCs into single-cell suspensions but has also been shown to digest surface CXCR4. Here, we assessed the regenerative effects of CXCR4high and CXCR4low MSCs in an immune-deficient mouse model of DSS-induced colitis. We found that transplantation of MSCs resulted in clinical improvement and histological recovery of intestinal epithelium. In contrary to our expectations, the levels of CXCR4 on transplanted MSCs did not affect their regenerative supporting potential, indicating that paracrine effects of MSCs may be largely responsible for their regenerative/protective effects.

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

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

Neuropeptide substance P attenuates colitis by suppressing inflammation and ferroptosis via the cGAS-STING signaling pathway.

Neuropeptide substance P (SP) belongs to a family of bioactive peptides and regulates many human diseases. This study aims to investigate the role and underlying mechanisms of SP in colitis. Here, activated SP-positive neurons and increased SP expression were observed in dextran sodium sulfate (DSS)-induced colitis lesions in mice. Administration of exogenous SP efficiently ameliorated the clinical symptoms, impaired intestinal barrier function, and inflammatory response. Mechanistically, SP protected mitochondria from damage caused by DSS or TNF-α exposure, preventing mitochondrial DNA (mtDNA) leakage into the cytoplasm, thereby inhibiting the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway. SP can also directly prevent STING phosphorylation through the neurokinin-1 receptor (NK1R), thereby inhibiting the activation of the TBK1-IRF3 signaling pathway. Further studies revealed that SP alleviated the DSS or TNF-α-induced ferroptosis process, which was associated with repressing the cGAS-STING signaling pathway. Notably, we identified that the NK1R inhibition reversed the effects of SP on inflammation and ferroptosis via the cGAS-STING pathway. Collectively, we unveil that SP attenuates inflammation and ferroptosis via suppressing the mtDNA-cGAS-STING or directly acting on the STING pathway, contributing to improving colitis in an NK1R-dependent manner. These findings provide a novel mechanism of SP regulating ulcerative colitis (UC) disease.

The Effect Mechanism of N6-adenosine Methylation (m6A) in Melatonin Regulated LPS-induced Colon Inflammation.

Colon inflammation is characterized by disturbances in the intestinal microbiota and inflammation. Melatonin (Mel) can improve colon inflammation. However, the underlying mechanism remains unclear. Recent studies suggest that m6A methylation modification may play an important role in inflammatory responses. This study aimed to explore the effects of melatonin and LPS-mediated m6A methylation on colon inflammation. Our study found that melatonin inhibits M1 macrophages, activates M2 macrophages, inhibit the secretion of pro-inflammatory factors, maintain colon homeostasis and improves colon inflammation through MTNR1B. In addition, the increased methylation level of m6A is associated with the occurrence of colon inflammation, and melatonin can also reduce the level of colon methylation to improve colon inflammation. Among them, the main methylated protein METTL3 can be inhibited by melatonin through MTNR1B. In a word, melatonin regulates m6A methylation by improving abnormal METTL3 protein level to reshape the microflora and activate macrophages to improve colon inflammation, mainly through MTNR1B.

Molecular modeling and simulation approaches to characterize potential molecular targets for burdock inulin to instigate protection against autoimmune diseases.

In the current study, we utilized molecular modeling and simulation approaches to define putative potential molecular targets for Burdock Inulin, including inflammatory proteins such as iNOS, COX-2, TNF-alpha, IL-6, and IL-1ß. Molecular docking results revealed potential interactions and good binding affinity for these targets; however, IL-1ß, COX-2, and iNOS were identified as the best targets for Inulin. Molecular simulation-based stability assessment demonstrated that inulin could primarily target iNOS and may also supplementarily target COX-2 and IL-1ß during DSS-induced colitis to reduce the role of these inflammatory mechanisms. Furthermore, residual flexibility, hydrogen bonding, and structural packing were reported with uniform trajectories, showing no significant perturbation throughout the simulation. The protein motions within the simulation trajectories were clustered using principal component analysis (PCA). The IL-1ß-Inulin complex, approximately 70% of the total motion was attributed to the first three eigenvectors, while the remaining motion was contributed by the remaining eigenvectors. In contrast, for the COX2-Inulin complex, 75% of the total motion was attributed to the eigenvectors. Furthermore, in the iNOS-Inulin complex, the first three eigenvectors contributed to 60% of the total motion. Furthermore, the iNOS-Inulin complex contributed 60% to the total motion through the first three eigenvectors. To explore thermodynamically favorable changes upon mutation, motion mode analysis was carried out. The Free Energy Landscape (FEL) results demonstrated that the IL-1ß-Inulin achieved a single conformation with the lowest energy, while COX2-Inulin and iNOS-Inulin exhibited two lowest-energy conformations each. IL-1ß-Inulin and COX2-Inulin displayed total binding free energies of - 27.76 kcal/mol and - 37.78 kcal/mol, respectively, while iNOS-Inulin demonstrated the best binding free energy results at - 45.89 kcal/mol. This indicates a stronger pharmacological potential of iNOS than the other two complexes. Thus, further experiments are needed to use inulin to target iNOS and reduce DSS-induced colitis and other autoimmune diseases.

hUC-MSCs therapy for Crohn's disease: efficacy in TNBS-induced colitis in rats and pilot clinical study.

BACKGROUND: The use of mesenchymal stem cells (MSCs) has recently emerged as a promising new therapeutic strategy for many diseases including perianal fistulizing Crohn's disease (CD). Whether hUC-MSCs can promote the healing of luminal ulcer in CD has not been studied so far. METHODS: The model of TNBS-induced colitis in rats was used to confirm the efficacy of hUC-MSCs in the treatment of CD. Then, seventeen CD patients refractory to or unsuitable for currently available therapies were enrolled and received once submucosal local injection through colonoscopy combined with once intravenous drip on the next day. All patients received a 24-week follow-up. Clinical and laboratory assessments were monitored at baseline, week 4, 8, 12, and 24. Endoscopic evaluations were conducted at baseline and week 12. Mucosal specimens were obtained at the margin of lesions by endoscopy biopsies and used for RNA sequencing. Two hUC-MSCs co-culture systems were established in vitro, one with the mucosa specimens and the other with M1 macrophages induced from THP1. The expressions of genes representing inflammation (TNFα, IL-6, and IL-1ß) and intestinal barrier function (ZO1, CLAUDIN1, and CDH1) were tested by RT-PCR. FINDINGS: hUC-MSCs treatment increased body weight and decreased disease activity index (DAI), colon macroscopic damage index (CMDI), and histopathological score (HPS) of rats with TNBS-induced colitis. The results of the clinical study also showed that this mode of hUC-MSCs application was associated with regression of intestinal ulceration. Eight patients (47%) got endoscopic responses (SES-CD improvement of ≥50% from baseline) and three patients (17.65%) got mucosal healing (SES-CD is zero), with a parallel improvement of clinical and laboratory parameters without serious adverse events. RNA sequencing showed hUC-MSCs therapy was associated with an upregulation of transcripts linked to intestinal epithelial barrier integrity and a downregulation of inflammatory signaling pathways in the intestinal mucosa, especially the TNF signaling pathway, IL-17 signaling pathway, and TLR signaling pathway. RNA expression of intestinal epithelial tight junction protein (ZO1, CLAUDIN1, and CDH1), and the RNA expression of major intestinal inflammatory factors in CD (IL-1ß, IL-6, and TNFα, p < 0.001 for all) were improved significantly. Moreover, hUC-MSCs could attenuate the polarization of M1 macrophage induced from THP1, thereby decreasing the mRNA expression of IL-1ß, IL-6, and TNFα significantly (p < 0.05 for all). TSG-6 expression was evaluated in hUC-MSCs culture supernatant after treatment with TNFα, IFNγ, and LPS for 48 h. And hUC-MSCs could inhibit the phosphorylation of JAK/STAT1 in the intestinal mucosa of CD patients. INTERPRETATION: hUC-MSCs transplantation alleviated TNBS-induced colitis in rats. In this pilot clinical study, preliminary data suggested that this approach to administering hUC-MSCs might have potential for clinical efficacy and manageable safety in treating refractory CD, potentially providing hope for better outcomes. No serious adverse events were observed. FUNDING: This work was funded by General Program of National Natural Science Foundation of China (Grant No. 82270639), the Scientific research project of Shanghai Municipal Health Committee (Grant No. 202240001), Specialty Feature Construction Project of Shanghai Pudong New Area Health Commission (Grant No. PWZzb2022-05), Shanghai East Hospital Youth Research and Cultivation Foundation program (Grant No. DFPY2022015), Peak Disciplines (Type IV) of Institutions of Higher Learning in Shanghai, Technology Development Project of Pudong Science, Technology and Economic Commission of Shanghai (Grant No. PKJ2021-Y08), Key Disciplines Group Construction Project of Shanghai Pudong New Area Health Commission (Grant No. PWZxq2022-06), Medical discipline Construction Project of Pudong Health Committee of Shanghai (Grant No. PWYgf2021-02) and National Natural Science Foundation of China (Grant No. 82300604).

Aryl Hydrocarbon Receptor Signalling in the Control of Gut Inflammation.

Aryl hydrocarbon receptor (AHR), a transcription factor activated by many natural and synthetic ligands, represents an important mediator of the interplay between the environment and the host's immune responses. In a healthy gut, AHR activation promotes tolerogenic signals, which help maintain mucosal homeostasis. AHR expression is defective in the inflamed gut of patients with inflammatory bowel diseases (IBD), where decreased AHR signaling is supposed to contribute to amplifying the gut tissue's destructive immune-inflammatory responses. We here review the evidence supporting the role of AHR in controlling the "physiological" intestinal inflammation and summarize the data about the therapeutic effects of AHR activators, both in preclinical mouse models of colitis and in patients with IBD.

Myeloid Cell-Derived IL-1 Signaling Damps Neuregulin-1 from Fibroblasts to Suppress Colitis-Induced Early Repair of the Intestinal Epithelium.

Neuregulin-1 (Nrg1, gene symbol: Nrg1), a ligand of the ErbB receptor family, promotes intestinal epithelial cell proliferation and repair. However, the dynamics and accurate derivation of Nrg1 expression during colitis remain unclear. By analyzing the public single-cell RNA-sequencing datasets and employing a dextran sulfate sodium (DSS)-induced colitis model, we investigated the cell source of Nrg1 expression and its potential regulator in the process of epithelial healing. Nrg1 was majorly expressed in stem-like fibroblasts arising early in mouse colon after DSS administration, and Nrg1-Erbb3 signaling was identified as a potential mediator of interaction between stem-like fibroblasts and colonic epithelial cells. During the ongoing colitis phase, a significant infiltration of macrophages and neutrophils secreting IL-1ß emerged, accompanied by the rise in stem-like fibroblasts that co-expressed Nrg1 and IL-1 receptor 1. By stimulating intestinal or lung fibroblasts with IL-1ß in the context of inflammation, we observed a downregulation of Nrg1 expression. Patients with inflammatory bowel disease also exhibited an increase in NRG1+IL1R1+ fibroblasts and an interaction of NRG1-ERBB between IL1R1+ fibroblasts and colonic epithelial cells. This study reveals a novel potential mechanism for mucosal healing after inflammation-induced epithelial injury, in which inflammatory myeloid cell-derived IL-1ß suppresses the early regeneration of intestinal tissue by interfering with the secretion of reparative neuregulin-1 by stem-like fibroblasts.