Mucosal Immunity Related to FOXP3+ Regulatory T Cells, Th17 Cells and Cytokines in Pediatric Inflammatory Bowel Disease

Prophylactic administration of overproducing-abscisic acid Bacillus licheniformis attenuated DSS-induced colitis in mice by regulating the gut microbiota and immune activity

BACKGROUND

Inflammatory bowel disease (IBD) involves the complex interplay among the mucosal barrier, microbiota, immunity and genetic factors. There are currently no satisfactory treatments for IBD. Administration of the probiotic Bacillus licheniformis (Bl) can improves colitis by regulating the gut microbiota. The phytohormone abscisic acid (ABA) treatment has favorable effects on immunity, as well as on inflammatory diseases like colitis. We hypothesized that the expression of an additional cyp gene by the Bl to increase its ABA production would enhance its effects.

RESULTS

In this study, we found that a Bl-cyp strain overexpressing the cyp gene secreted more ABA into its supernatant than either the parental Bl stain or a Bl-pET82a strain expressing only a vector pET82a when these bacteria were grown in Nfb medium for 48 h. The prophylactic administration of the Bl-cyp strain culture more effectively attenuated dextran sodium sulfate (DSS)-induced colitis in mice compared to the Bl and Bl-pET28a strains. These findings were associated with significantly reduced epithelial barrier damage, as well as increased number of goblet cells and expression levels of occludin gene in the colonic epithelial layer, and decreased serum LPS levels in the Bl-cyp group. In addition, the administration of Bl-cyp strain effectively regulated the disordered gut microbiota by improving their diversity, richness and compositions more than the Bl or Bl-pET82a strain, including the ratio of Bacteroidota: Bacillota. It also inhibited the excessive growth of opportunistic pathogen Escherichia just like the Bl or Bl-pET82a strain. Moreover, the preventive administration of the Bl-cyp strain to mice following DSS-induced colitis enhanced the proportion of Treg cells and suppressed the proportion of Th17 cells in mesenteric lymph nodes (MLNs), decreased the levels of pro-inflammatory cytokines TNF-α, IL-6, and IL-22, and increased the level of anti-inflammatory IL-10 in colon tissues, similar to treatment with a high concentration of the ABA standard (ABA-H). Notably, the treatment with the Bl-cyp strain more effectively regulated the disordered microbiota than the ABA-H.

CONCLUSIONS

The administration of the Bl-cyp strain may provide a novel preventive approach for IBD, and may exert its effects by modulating the gut microbiota and host's immune status.

FoxP3-positive T regulatory cells and its effector mechanisms in Crohn's disease: an immunohistochemical and image morphometric analysis on endoscopic mucosal biopsies

OBJECTIVE

Crohn's disease (CD) is an immune inflammatory disorder of the gastrointestinal tract arising from a complex interplay of genetic, environmental, microbiome, and immune factors. Regulatory T cells (Tregs), characterized by FoxP3 expression, are crucial for maintaining immune homeostasis through PD-1/PD-L1 interaction, interleukin (IL)-10 release, and granzyme (GrB) production. This study aimed to elucidate the role of FoxP3 positive (+) Tregs in CD.

METHODS

Segmental colonoscopic biopsies from 46 treatment-naive CD cases (34 adults and 12 children) categorized into noninflamed [n = 32; Nancy histologic index (NHI) 0, 1] and inflamed (n = 100; NHI 2-4) mucosae using NHI. CD4, FoxP3, PD-1, IL-10, and GrB immunoexpression were analyzed by eyeballing and image morphometry. Findings were correlated with activity, granulomas, and skip lesions; and compared with site-matched non-inflammatory bowel disease (IBD) controls (n = 30).

RESULTS

FoxP3+ Tregs, IL-10, PD-1, and GrB expressions were significantly higher in NHI 3-4 mucosae than in NHI 0-1 and controls (P < 0.05). No significant differences were observed between adults and children, whereas those with granulomas had increased expression (P = 0.045). The FoxP3 : CD4 ratio positively correlated with IL-10 (Spearman, r = 0.307, P = 0.002), GrB (r = 0.302, P = 0.002), but not with PD-1 (r = 0.98, P = 0.33).

CONCLUSIONS

Our findings point to the possibility of a qualitative defect in FoxP3+ Tregs in CD. The functional arms of Tregs in CD need to be elucidated further in larger prospective cohorts to validate our observations and pave the way for future immunotherapy.

The mucosal immunity in crustaceans: Inferences from other species

Crustaceans such as shrimps and crabs, hold significant ecological significance and substantial economic value within marine ecosystems. However, their susceptibility to disease outbreaks and pathogenic infections has posed major challenges to production in recent decades. As invertebrate, crustaceans primarily rely on their innate immune system for defense, lacking the adaptive immune system found in vertebrates. Mucosal immunity, acting as the frontline defense against a myriad of pathogenic microorganisms, is a crucial aspect of their immune repertoire. This review synthesizes insights from comparative immunology, highlighting parallels between mucosal immunity in vertebrates and innate immune mechanisms in invertebrates. Despite lacking classical adaptive immunity, invertebrates, including crustaceans, exhibit immune memory and rely on inherent "innate immunity factors" to combat invading pathogens. Drawing on parallels from mammalian and piscine systems, this paper meticulously explores the complex role of mucosal immunity in regulating immune responses in crustaceans. Through the extrapolation from well-studied models like mammals and fish, this review infers the potential mechanisms of mucosal immunity in crustaceans and provides insights for research on mucosal immunity in crustaceans.

Interaction of Th17 differentiations-related gene polymorphisms and environmental factors contributing to the disease classification, complications, and surgical risks of Crohn's disease in the Chinese Han population

OBJECTIVES

Few studies have been conducted on gene-environment interactions in the Chinese population with Crohn's disease (CD). We aimed to investigate the association between single nucleotide polymorphisms (SNPs) on the T helper 17 (Th17) cell and CD susceptibility/performance in Chinese individuals.

METHODS

We conducted a case-control and case-only study at the Peking Union Medical College Hospital. Four SNPs related to the Th17 cell pathway genes were prioritized, including rs2284553 (interferon gamma receptor 2), rs7517847 (interleukin 23 receptor), rs7773324 (interferon regulatory factor 4), and rs4263839 (tumor necrosis factor superfamily 15). SNP frequency was calculated, and gene-environment interaction was assessed by multifactor dimensionality reduction analysis.

RESULTS

Altogether 159 CD patients and 316 healthy controls were included. All analyzed SNPs were found in Hardy-Weinberg equilibrium (P > 0.05). The frequency of rs2284553-A allele and rs4263839-A allele were lower in CD patients compared with controls (P < 0.05). While the rs4263839-A allele was more prevalent in ileocolonic CD patients than in those with isolated small intestinal or colonic disease (P = 0.035). Gene-environment interactions revealed associations between rs2284553 and breastfeeding, sunshine exposure, and fridge-stored food, affecting age at diagnosis, intestinal involvement, and intestinal stricture. Interaction of rs4263839 and breastfeeding influenced small intestinal lesions and intestinal stricture in CD.

CONCLUSIONS

This study provided information on the genetic background in Chinese CD patients. Incorporating these SNPs into predictive models may improve risk assessment and outcome prediction. Gene-environment interaction contributes to the understanding of CD pathogenesis.

Changes in SOD and NF-κB Levels in Substantia Nigra and the Intestine through Oxidative Stress Effects in a Wistar Rat Model of Ozone Pollution

This work aimed to elucidate how O3 pollution causes a loss of regulation in the immune response in both the brain and the intestine. In this work, we studied the effect of exposing rats to low doses of O3 based on the association between the antioxidant response of superoxide dismutase (SOD) levels and the nuclear factor kappa light chains of activated B cells (NFκB) as markers of inflammation. Method: Seventy-two Wistar rats were used, divided into six groups that received the following treatments: Control and 7, 15, 30, 60, and 90 days of O3. After treatment, tissues were extracted and processed using Western blotting, biochemical, and immunohistochemical techniques. The results indicated an increase in 4-hydroxynonenal (4HNE) and Cu/Zn-SOD and a decrease in Mn-SOD, and SOD activity in the substantia nigra, jejunum, and colon decreased. Furthermore, the translocation of NFκB to the nucleus increased in the different organs studied. In conclusion, repeated exposure to O3 alters the regulation of the antioxidant and inflammatory response in the substantia nigra and the intestine. This indicates that these factors are critical in the loss of regulation in the inflammatory response; they respond to ozone pollution, which can occur in chronic degenerative diseases.

Biomarkers of ulcerative colitis disease activity CXCL1, CYP2R1, LPCAT1, and NEU4 and their relationship to immune infiltrates

The diagnosis and assessment of ulcerative colitis (UC) poses significant challenges, which may result in inadequate treatment and a poor prognosis for patients. This study aims to identify potential activity biomarkers for UC and investigate the role of infiltrating immune cells in the disease. To perform gene set enrichment analysis, we utilized the cluster profiler and ggplot2 packages. Kyoto encyclopedia of genes and genomes was used to analyze degenerate enrichment genes. Significant gene set enrichment was determined using the cluster profiler and ggplot2 packages. Additionally, quantitative PCR (qRT-PCR) was employed to validate the expression of each marker in the ulcerative colitis model. We identified 651 differentially expressed genes (DEGs) and further investigated potential UC activity biomarkers. Our analysis revealed that CXCL1 (AUC = 0.710), CYP2R1 (AUC = 0.863), LPCAT1 (AUC = 0.783), and NEU4 (AUC = 0.833) were promising activity markers for the diagnosis of UC. Using rat DSS model, we validated these markers through qRT-PCR, which showed statistically significant differences between UC and normal colon mucosa. Infiltrating immune cell analysis indicated that M1 macrophages, M2 macrophages, activated dendritic cells (DCs), and neutrophils played crucial roles in the occurrence and progression of UC. Moreover, the activity markers exhibited varying degrees of correlation with activated memory CD4 T cells, M0 macrophages, T follicular helper cells, memory B cells, and activated DCs. The potential diagnostic genes for UC activity, such as CXCL1, CYP2R1, LPCAT1, and NEU4, as well as the infiltration of immune cells, may contribute to the pathogenesis and progression of UC.

Ozone Environmental Pollution: Relationship between the Intestine and Neurodegenerative Diseases

Repeated exposure to environmental ozone causes a chronic state of oxidative stress. This state is present in chronic degenerative diseases and induces a loss of control of the inflammatory response. Redox system dysfunction and failures in control of inflammatory responses are involved in a vicious circle that maintains and increases the degenerative process. The intestine also responds to secondary reactive species formed by exposure to ozone doses, generating noxious stimuli that increase degenerative damage. This review aims to elucidate how environmental pollution, mainly by ozone, induces a state of chronic oxidative stress with the loss of regulation of the inflammatory response, both in the intestine and in the brain, where the functionality of both structures is altered and plays a determining role in some neurodegenerative and chronic degenerative diseases. For this purpose, we searched for information on sites such as the Cochrane Library Database, PubMed, Scopus, and Medscape. Reviewing the data published, we can conclude that environmental pollutants are a severe health problem. Ozone pollution has different pathways of action, both molecular and systemic, and participates in neurodegenerative diseases such as Parkinson's and Alzheimer's disease as well in bowel diseases as Inflammatory Bowel Disease, Crohn's Disease, and Irritable Bowel Syndrome.

Cytokine-stimulated human amniotic epithelial cells alleviate DSS-induced colitis in mice through anti-inflammation and regulating Th17/Treg balance

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon characterized by immune dysregulation. Restoration of the balance between regulatory T (Tregs) and T helper 17 (Th17) cells improves UC symptoms. Human amniotic epithelial cells (hAECs) have emerged as a promising therapeutic option for UC because of their immunomodulatory properties. In this study, we aimed to optimize and maximize the therapeutic potential of hAECs by pre-treating them with tumor necrosis factor (TNF)-α and interferon (IFN)-γ (pre-hAECs) for UC treatment. We evaluated the efficacy of hAECs and pre-hAECs in treating dextran sulfate sodium (DSS)-induced colitis mice. Compared to hAECs, pre-hAECs were found to be more effective in alleviating colitis in acute DSS mouse models than in the controls. Additionally, pre-hAEC treatment significantly reduced weight loss, shortened the colon length, decreased the disease activity index, and effectively maintained the recovery of colon epithelial cells. Furthermore, pre-hAEC treatment significantly inhibited the production of pro-inflammatory cytokines, such as interleukin (IL)-1β and TNF-α, and promoted the expression of anti-inflammatory cytokines, such as IL-10. Both in vivo and in vitro studies revealed that pre-treatment with hAECs significantly increased the number of Treg cells, decreased the numbers of Th1, Th2, and Th17 cells, and regulated the balance of Th17/Treg cells. In conclusion, our results revealed that hAECs pre-treated with TNF-α and IFN-γ were highly effective in treating UC, suggesting their potential as therapeutic candidates for UC immunotherapy.

Interleukin-35 Enhances Regulatory T Cell Function by Potentially Suppressing Their Transdifferentiation into a T Helper 17-Like Phenotype in Kawasaki Disease

Interleukin-35 (IL-35) modulates immune cell activity in inflammation and autoimmune disorders. However, its specific effects on regulatory T cells (Tregs) in Kawasaki disease remain ambiguous. We enrolled 37 patients with Kawasaki disease and 20 healthy controls in this study. The percentages of CD4⁺CD25⁺CD127^dim/- Tregs and CD4⁺IL-17A⁺ T helper 17 (Th17) cells were determined via flow cytometry. Tregs were enriched and stimulated by recombinant IL-35. Immunosuppressive activity of Tregs was via co-culture with autologous CD4⁺CD25^- T cells. Purified Tregs were cultured for Th17 polarization, and the influence of IL-35 on Tregs transdifferentiation into a Th17-like phenotype was determined. The percentage of Tregs was elevated in patients with Kawasaki disease and positively correlated with C-reactive protein levels. There was no significant difference in the percentage of Th17 cells between the two groups. IL-35 stimulation increased the percentage of Tregs in both groups, but decreased the percentage of Tregs Th17 cells in affected patients. IL-35 enhanced the immunosuppressive activity of Tregs in both groups, resulting in decreased cellular proliferation and increased IL-35 subunit mRNA relative levels in co-culture system. IL-35 did not affect the immune checkpoint molecule expression in Tregs, but inhibited the transdifferentiation of Tregs into a Th17-like phenotype in affected patients, indicating by the down-regulations of C-C motif chemokine receptor-4/6 expression, retinoid-related orphan nuclear receptor γt mRNA levels, and IL-17 secretion. IL-35 contributes to the immunosuppressive function of Tregs by inhibiting the cellular proliferation and transdifferentiation of Tregs into a Th17-like phenotype, which may be a protective mechanism against Kawasaki disease.

Aryl hydrocarbon receptor activation ameliorates experimental colitis by modulating the tolerogenic dendritic and regulatory T cell formation

Background

Intestinal immune dysfunction is involved in the onset of Crohn’s disease (CD). Dendritic cells (DCs), antigen-presenting cells, play a key role in the maintenance of intestinal immune homeostasis. The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor widely expressed in various immune cells, including DCs. Although AhR plays an important role in immune tolerance, its role in the DCs is unclear. The purpose of this study was to investigate whether the activation of AhR can induce tolerogenic DCs (tolDCs) and the differentiation of regulatory T (Treg) cells, as well as ameliorate experimental colitis.

Results

AhR activation in the DCs resulted in a lower expression of surface markers such as CD80, CD83, CD86, and pro-inflammatory cytokine production, and higher anti-inflammatory production (IL-1β, IL-23, and IL-12) compared to the control DCs. The surface dendrites in DCs were significantly reduced following AhR activation by 6-formylindolo [3,2-b]carbazole (FICZ). Such DCs with FICZ-mediated activation of AhR, namely tolDCs, promoted Treg cell differentiation. Adoptive transfer of tolDCs to a TNBS-induced colitis mouse model significantly alleviated the severity of inflammation by improving the colon length and decreasing the disease activity index (DAI) and histopathological score. Moreover, the transferred tolDCs decreased the frequency of Th17 cells and increased the frequency of Treg cells in the spleen and mesenteric lymph nodes (MLNs) in murine colitis models.

Conclusions

Activation of AhR in the DCs could induce tolDCs, and the transplantation of tolDCs may help in relieving intestinal inflammation and maintaining the Th17/Treg differentiation balance. Thus, our data suggest that AhR may be a potential therapeutic target for CD.

The Therapeutic Role of Short-Chain Fatty Acids Mediated Very Low-Calorie Ketogenic Diet-Gut Microbiota Relationships in Paediatric Inflammatory Bowel Diseases

The very low-calorie ketogenic diet (VLCKD) has been recognized as a promising dietary regimen for the treatment of several diseases. Short-chain fatty acids (SCFAs) produced by anaerobic bacterial fermentation of indigestible dietary fibre in the gut have potential value for their underlying epigenetic role in the treatment of obesity and asthma-related inflammation through mediating the relationships between VLCKD and the infant gut microbiota. However, it is still unclear how VLCKD might influence gut microbiota composition in children, and how SCFAs could play a role in the treatment of inflammatory bowel disease (IBD). To overcome this knowledge gap, this review aims to investigate the role of SCFAs as key epigenetic metabolites that mediate VLCKD-gut microbiota relationships in children, and their therapeutic potential in IBD.

Cysteine protease of Clonorchis sinensis alleviates DSS-induced colitis in mice

Background

Currently, inflammatory bowel disease (IBD) has become a global chronic idiopathic disease with ever-rising morbidity and prevalence. Accumulating evidence supports the IBD-hygiene hypothesis that helminths and their derivatives have potential therapeutic value for IBD. Clonorchis sinensis (C. sinensis) mainly elicit Th2/Treg-dominated immune responses to maintain long-term parasitism in the host. This study aimed to evaluate the therapeutic effects of cysteine protease (CsCP) and adult crude antigen (CsCA) of C. sinensis, and C. sinensis (Cs) infection on DSS-induced colitis mice.

Methods

BALB/c mice were given 5% DSS daily for 7 days to induce colitis. During this period, mice were treated with rCsCP, CsCA or dexamethasone (DXM) every day, or Cs infection which was established in advance. Changes in body weight, disease activity index (DAI), colon lengths, macroscopic scores, histopathological findings, myeloperoxidase (MPO) activity levels, regulatory T cell (Treg) subset levels, colon gene expression levels, serum cytokine levels, and biochemical indexes were measured.

Results

Compared with Cs infection, rCsCP and CsCA alleviated the disease activity of acute colitis more significant without causing abnormal blood biochemical indexes. In comparison, rCsCP was superior to CsCA in attenuating colonic pathological symptoms, enhancing the proportion of Treg cells in spleens and mesenteric lymph nodes, and improving the secretion of inflammatory-related cytokines (e.g., IL-2, IL-4, IL-10 and IL-13) in serum. Combined with RNA-seq data, it was revealed that CsCA might up-regulate the genes related to C-type lectin receptor and intestinal mucosal repair related signal pathways (e.g., Cd209d, F13a1 and Cckbr) to reduce colon inflammation and benefit intestinal mucosal repair. Dissimilarly, rCsCP ameliorated colitis mainly through stimulating innate immunity, such as Toll like receptor (TLR) signaling pathway, down-regulating the expression of inflammatory cytokines (e.g., IL-12b, IL-23r and IL-7), thereby restraining the differentiation of Th1/Th17 cells.

Conclusions

Both rCsCP and CsCA showed good therapeutic effects on the treatment of acute colitis, but rCsCP is a better choice. rCsCP is a safe, effective, readily available and promising therapeutic agent against IBD mainly by activating innate immunity and regulating the IL-12/IL-23r axis.

Cytokine profile in serum and gingival crevicular fluid of children with inflammatory bowel disease: A case-control study

BACKGROUND

To evaluate the cytokine profile in gingival crevicular fluid (GCF) and serum of pediatric inflammatory bowel disease (IBD) patients and determine the cluster patterns of cytokines.

METHODS

Fifty IBD patients and 21 systemically healthy children were enrolled in the study. The GCF samples were collected from the participants during periodontal examination and periodontal indices were recorded. Based on activity indexes and response to conventional treatment, patients with IBD were further categorized into subgroups as: remission, active disease, and treatment-resistant. Serum samples were obtained from IBD patients to determine serum levels of cytokines. The levels of pro- (interleukin (IL)-1β, IL-12, IL-21, IL-22, IL-23, IL-17A, IL-17F) and anti-inflammatory (IL-4, IL-10) cytokines in serum and GCF were measured using Enzyme-linked Immunosorbent Assay (ELISA) kits.

RESULTS

Among 50 IBD patients, 58% were in remission, 20% had active disease, and 22% were defined as treatment-resistant. The severity of gingival inflammation measured by the criteria of Löe had increasing trends in IBD patients with active disease and treatment resistance. GCF IL-1β level was lower and GCF IL-4 and GCF IL-23 levels were higher in IBD patients compared to healthy controls. In the active disease group, more cytokine clusters occurred compared to the control group and other IBD subgroups, as explained by increased cytokine-cytokine interactions.

CONCLUSIONS

Considering the increased complexity of cytokine interactions and the increased severity of gingival inflammation in patients with active disease, it can be concluded that disease activity might have an impact on gingival inflammation in pediatric patients with IBD.

Intestinal toxicity of micro- and nano-particles of foodborne titanium dioxide in juvenile mice: Disorders of gut microbiota-host co-metabolites and intestinal barrier damage

The wide use of TiO₂ particles in food and the high exposure risk to children have prompted research into the health risks of TiO₂. We used the microbiome and targeted metabolomics to explore the potential mechanism of intestinal toxicity of foodborne TiO₂ micro-/nanoparticles after oral exposure for 28 days in juvenile mice. Results showed that the gut microbiota-including the abundance of Bacteroides, Bifidobacterium, Lactobacillus, and Prevotella-changed dynamically during exposure. The organic inflammatory response was activated, and lipopolysaccharide levels increased. Intestinal toxicity manifested as increased mucosal permeability, impaired intestinal barrier, immune damage, and pathological changes. The expression of antimicrobial peptides, occludin, and ZO-1 significantly reduced, while that of JNK2 and Src/pSrc increased. Compared with micro-TiO₂ particles, the nano-TiO₂ particles had strong toxicity. Fecal microbiota transplant confirmed the key role of gut microbiota in intestinal toxicity. The levels of gut microbiota-host co-metabolites, including pyroglutamic acid, L-glutamic acid, phenylacetic acid, and 3-hydroxyphenylacetic acid, changed significantly. Significant changes were observed in the glutathione and propanoate metabolic pathways. There was a significant correlation between the changes in gut microbiota, metabolites, and intestinal cytokine levels. These, together with the intestinal barrier damage signaling pathway, constitute the network mechanism of the intestinal toxicity of TiO₂ particles.

Pediococcus pentosaceus CECT 8330 protects DSS-induced colitis and regulates the intestinal microbiota and immune responses in mice

Background

Compelling evidences demonstrated that gut microbiota dysbiosis plays a critical role in the pathogenesis of inflammatory bowel diseases (IBD). Therapies for targeting the microbiota may provide alternative options for the treatment of IBD, such as probiotics. Here, we aimed to investigate the protective effect of a probiotic strain, Pediococcus pentosaceus (P. pentosaceus) CECT 8330, on dextran sulfate sodium (DSS)-induced colitis in mice.

Methods

C57BL/6 mice were administered phosphate-buffered saline (PBS) or P. pentosaceus CECT 8330 (5 × 10⁸ CFU/day) once daily by gavage for 5 days prior to or 2 days after colitis induction by DSS. Weight, fecal conditions, colon length and histopathological changes were examined. ELISA and flow cytometry were applied to determine the cytokines and regulatory T cells (Treg) ratio. Western blot was used to examine the tight junction proteins (TJP) in colonic tissues. Fecal short-chain fatty acids (SCFAs) levels and microbiota composition were analyzed by targeted metabolomics and 16S rRNA gene sequencing, respectively. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and Cluster of orthologous groups of proteins (COG) pathway analysis were used to predict the microbial functional profiles.

Results

P. pentosaceus CECT 8330 treatment protected DSS-induced colitis in mice as evidenced by reducing the weight loss, disease activity index (DAI) score, histological damage, and colon length shortening. P. pentosaceus CECT 8330 decreased the serum levels of proinflammatory cytokines (TNF-α, IL-1β, and IL-6), and increased level of IL-10 in DSS treated mice. P. pentosaceus CECT 8330 upregulated the expression of ZO-1, Occludin and the ratio of Treg cells in colon tissue. P. pentosaceus CECT 8330 increased the fecal SCFAs level and relative abundances of several protective bacteria genera, including norank_f_Muribaculaceae, Lactobacillus, Bifidobacterium, and Dubosiella. Furthermore, the increased abundances of bacteria genera were positively correlated with IL-10 and SCFAs levels, and negatively associated with IL-6, IL-1β, and TNF-α, respectively. The KEGG and COG pathway analysis revealed that P. pentosaceus CECT 8330 could partially recover the metabolic pathways altered by DSS.

Conclusions

P. pentosaceus CECT 8330 administration protects the DSS-induced colitis and modulates the gut microbial composition and function, immunological profiles, and the gut barrier function. Therefore, P. pentosaceus CECT 8330 may serve as a promising probiotic to ameliorate intestinal inflammation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03235-8.

Treg/Th17 Cell Balance in Patients with Hepatitis B Virus-Related Acute-on-Chronic Liver Failure at Different Disease Stages

Background

T-helper 17 (Th17) and CD4⁺CD25⁺ T-regulatory (Treg) cells play important roles in the pathogenesis of hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF). This study is aimed at investigating shifts in Treg/Th17 balance in the peripheral blood of HBV-ACLF patients at different disease stages.

Methods

Sixty HBV-ACLF patients, admitted to the First Hospital of Hunan University of Chinese Medicine, China, including early-stage (n = 20), middle-stage (n = 20), and late-stage patients (n = 20), were enrolled in the study. In addition, 20 patients with chronic hepatitis B and 20 healthy volunteers were also included in the study as controls. Flow cytometry, cytometric bead array, and quantitative real-time PCR protocols were used to evaluate the expression of Treg and Th17 cells as well as of related cytokines.

Results

The levels of Th17 cells and their effectors interleukin- (IL-) 17A, IL-23, and tumor necrosis factor-α increased with disease progression. Similarly, Treg cells and their effector cytokines transforming growth factor-β and IL-10 also increased. Although Treg and Th17 levels were positively correlated, the latter were always at higher numbers. Noteworthy, the Treg/Th17 ratio gradually decreased and was negatively correlated with ACLF severity. FoxP3 levels in the peripheral blood gradually decreased with ACLF progression, whereas ROR-γt gradually increased. Serum c-reactive protein, procalcitonin, and lipopolysaccharide were also upregulated with disease progression and positively correlated with Th17 abundance. Further, Th17, IL-17A, and IL-23 were independent risk factors for ACLF. A prognostic model for HBV-ACLF was established, with a correct prediction rate of 90.00% (54/60).

Conclusion

Treg/Th17 imbalance occurs throughout the pathogenic course of HBV-ACLF, with an imbalance shift toward Th17. Hence, the Th17-mediated inflammatory response drives HBV-ACLF-associated inflammation and supports the pathological mechanisms of liver failure.

Elevated Levels of IL-27 Are Associated with Disease Activity in Patients with Crohn's Disease

Immune disorders play an important role in the pathogenesis of Crohn's disease (CD). Notably, the increased immune response of Th1 cells and related cytokines is associated with the onset of CD. IL-27 is a newly discovered IL-12-related cytokine, but its expression and clinical significance in CD patients are still controversial. This study is aimed at evaluating the serum levels of IL-27 in CD patients and analyzing their clinical significance. The results indicated that serum levels of IL-27 in CD patients were significantly higher than those in control subjects (median (interquartile range (IQR)): 110.0 (95.0, 145.0) vs. 85.0 (80.0, 95.0) pg/ml, P < 0.001). Furthermore, the IL-27 levels significantly increased in CD patients at the active stage compared with CD patients in remission (CDR) (127.5 (100.0, 150.0) vs. 90 (80.0, 110.0) pg/ml, P < 0.001). However, there was no difference in IL-27 levels between CDR and control subjects. The levels of IL-27 were positively correlated with Crohn's disease activity index (CDAI), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), fecal calprotectin (FC), and Simple Endoscopic Score for Crohn's Disease (SES-CD) and negatively correlated with hemoglobin (Hb) and serum albumin (ALB). IL-27 combined with CRP favored the prediction of CD activity (area under the curve (AUC): 0.88). Additionally, the proportions of Th17 and Th1 cells in peripheral blood were higher in CD patients than in control subjects. Active CD patients exhibited significantly higher proportions of Th17 and Th1 cells than those in remission. Moreover, correlation analysis indicated that the serum levels of IL-27 were positively associated with the frequency of Th17 cells in CD patients (r = 0.519, P = 0.013) but not associated with the frequency of Th1 cells in CD patients. IL-27 is positively associated with multiple inflammation indicators and may exert a proinflammatory profile by regulating Th17 cell differentiation in the development of Crohn's disease. In the future, IL-27 combined with CRP is expected to become an important biological marker of CD activity.

Lactobacillus paracasei R3 protects against dextran sulfate sodium (DSS)-induced colitis in mice via regulating Th17/Treg cell balance

Inflammatory bowel diseases (IBD), mainly comprising ulcerative colitis (UC) and Crohn's Disease, are most often a polygenic disorder with contributions from the intestinal microbiome, defects in barrier function, and dysregulated host responses to microbial stimulation. Strategies that target the microbiota have emerged as potential therapies and, of these, probiotics have gained the greatest attention. Herein, we isolated a strain of Lactobacillus paracasei R3 (L.p R3) with strong biofilm formation ability from infant feces. Interestingly, we also found L.p R3 strain can ameliorate the general symptoms of murine colitis, alleviate inflammatory cell infiltration and inhibit Th17 while promote Treg function in murine dextran sulfate sodium (DSS)-induced colitis. Overall, this study suggested that L.p R3 strain significantly improves the symptoms and the pathological damage of mice with colitis and influences the immune function by regulating Th17/Treg cell balance in DSS-induced colitis in mice.

Lactobacillus paracasei R3 protects against dextran sulfate sodium (DSS)-induced colitis in mice via regulating Th17/Treg cell balance

Inflammatory bowel diseases (IBD), mainly comprising ulcerative colitis (UC) and Crohn's Disease, are most often a polygenic disorder with contributions from the intestinal microbiome, defects in barrier function, and dysregulated host responses to microbial stimulation. Strategies that target the microbiota have emerged as potential therapies and, of these, probiotics have gained the greatest attention. Herein, we isolated a strain of Lactobacillus paracasei R3 (L.p R3) with strong biofilm formation ability from infant feces. Interestingly, we also found L.p R3 strain can ameliorate the general symptoms of murine colitis, alleviate inflammatory cell infiltration and inhibit Th17 while promote Treg function in murine dextran sulfate sodium (DSS)-induced colitis. Overall, this study suggested that L.p R3 strain significantly improves the symptoms and the pathological damage of mice with colitis and influences the immune function by regulating Th17/Treg cell balance in DSS-induced colitis in mice.

Lactobacillus paracasei R3 protects against dextran sulfate sodium (DSS)-induced colitis in mice via regulating Th17/Treg cell balance

Inflammatory bowel diseases (IBD), mainly comprising ulcerative colitis (UC) and Crohn's Disease, are most often a polygenic disorder with contributions from the intestinal microbiome, defects in barrier function, and dysregulated host responses to microbial stimulation. Strategies that target the microbiota have emerged as potential therapies and, of these, probiotics have gained the greatest attention. Herein, we isolated a strain of Lactobacillus paracasei R3 (L.p R3) with strong biofilm formation ability from infant feces. Interestingly, we also found L.p R3 strain can ameliorate the general symptoms of murine colitis, alleviate inflammatory cell infiltration and inhibit Th17 while promote Treg function in murine dextran sulfate sodium (DSS)-induced colitis. Overall, this study suggested that L.p R3 strain significantly improves the symptoms and the pathological damage of mice with colitis and influences the immune function by regulating Th17/Treg cell balance in DSS-induced colitis in mice.

Opportunities to Target T Cell Trafficking in Pediatric Inflammatory Bowel Disease

T cell subsets are considered central orchestrators of inflammation and homeostasis in the intestine and are established targets for the treatment of inflammatory bowel disease. While approaches aimed at the neutralization of T cell effector cytokines have provided significant benefits for pediatric and adult patients, more recent strategies aimed at inhibiting the infiltration of pathogenic T cell subsets have also emerged. In this review, we describe current knowledge surrounding the function of T cell subsets in pediatric inflammatory bowel disease and outline approaches aimed at targeting T cell trafficking to the intestine which may represent a new treatment option for pediatric inflammatory bowel disease.

Differential influences of the BPA, BPS and BPF on in vitro IL-17 secretion by mouse and human T cells

The endocrine disruptor and food contaminant bisphenol A (BPA) is frequently present in consumer plastics and can produce several adverse health effects participating in the development of inflammatory and autoimmune diseases. Regulatory restrictions have been established to prevent risks for human health, leading to the substitution of BPA by structural analogues, such as bisphenol S (BPS) and F (BPF). In this study, we aimed at comparing the in vitro impact of these bisphenols from 0.05 to 50,000 nM on Th17 differentiation, frequency and function in mouse systemic and intestinal immune T cells and in human blood T cells. This study reports the ability of these bisphenols, at low and environmentally relevant concentration, i.e, 0.05 nM, to increase significantly IL-17 production in mouse T cells but not in human T lymphocytes. The use of an aryl hydrocarbon receptor (AhR) specific inhibitor demonstrated its involvement in this bisphenol-induced IL-17 production. We also observed an increased IL-17 secretion by BPS and BPF, and not by BPA, in mouse naive T cells undergoing in vitro Th17 differentiation. In total, this study emphasizes the link between bisphenol exposures and the susceptibility to develop immune diseases, questioning thus the rational of their use to replace BPA.

Enhancement of Circulating and Intestinal T Regulatory Cells and Their Expression of Helios and Neuropilin-1 in Children with Inflammatory Bowel Disease

Background/Aims

The proportions of intestinal and peripheral regulatory T cells (Tregs) in pediatric inflammatory bowel disease (IBD) were poorly investigated, as well as different subsets of these cells. Helios and Neuropilin-1 were proposed as markers differentiating between thymic and peripheral Tregs. Therefore, the aim of current work was to investigate the proportions of Tregs and expression of Helios and Neuropilin-1 in Tregs in peripheral blood and intestinal mucosa of children with inflammatory bowel disease.

Materials and methods

Fifteen patients newly diagnosed with inflammatory bowel disease: ulcerative colitis (n=7) and Crohn's disease (n=8) were included in the study. Nine children who presented with no abnormalities in colonoscopy served as a control group. Quantification of regulatory T cells of the CD4⁺CD25^highFOXP3⁺ phenotype, as well as Helios⁺ and Neuropilin-1⁺ in peripheral blood and bowel mucosa was based on multicolor flow cytometry.

Results

The rates of circulating and intestinal Tregs were significantly higher in the studied group than in the control group. The rate of intestinal T regulatory lymphocytes was significantly higher than circulating Tregs in patients with IBD, but not in the control group. The median proportion of circulating FOXP3⁺Helios⁺ cells amounted to 24.83% in IBD patients and 15.93% in the controls. The median proportion of circulating FOXP3⁺Nrp-1⁺ cells was 34.23% in IBD and 21.01% in the control group. No statistically significant differences were noted for the circulating FOXP3⁺Helios⁺ cells and FOXP3⁺Nrp-1⁺ cells between the studied and the control group.

Conclusion

The rates of circulating and intestinal T regulatory cells are increased in naïve pediatric patients with IBD. The rate of Tregs is higher in intestinal mucosa than in peripheral blood in patients with IBD. Flow cytometry is a valuable method assessing the composition of infiltrates in inflamed tissue. Helios and Neuropilin-1 likely cannot serve as markers to differentiate between natural and adaptive Tregs.

Mucosal immunity and tRNA, tRF, and tiRNA

Mucosal immunity has crucial roles in human diseases such as respiratory tract infection, inflammatory bowel diseases (IBD), and colorectal cancer (CRC). Recent studies suggest that the mononuclear phagocyte system, cancer cells, bacteria, and viruses induce the mucosal immune reaction by various pathways, and can be major factors in the pathogenesis of these diseases. Transfer RNA (tRNA) and its fragments, including tRNA-derived RNA fragments (tRFs) and tRNA-derived stress-induced RNAs (tiRNAs), have emerged as a hot topic in recent years. They not only are verified as essential for transcription and translation but also play roles in cellular homeostasis and functions, such as cell metastasis, proliferation, and apoptosis. However, the specific relationship between their biological regulation and mucosal immunity remains unclear to date. In the present review, we carry out a comprehensive discussion on the specific roles of tRNA, tRFs, and tiRNAs relevant to mucosal immunity and related diseases.

Curcumin ameliorates DSS‑induced colitis in mice by regulating the Treg/Th17 signaling pathway

Curcumin has a therapeutic effect on ulcerative colitis, but the underlying mechanism has yet to be elucidated. The aim of the present study was to clarify the possible mechanisms. Dextran sulfate sodium-induced colitis mice were treated with curcumin via gavage for 7 days. The effects of curcumin on disease activity index (DAI) and pathological changes of colonic tissue in mice were determined. Interleukin (IL)-6, IL-10, IL-17 and IL-23 expression levels were measured by ELISA. Flow cytometry was used to detect the ratio of mouse spleen regulatory T cells (Treg)/Th17 cells, and western blotting was used to measure the nuclear protein hypoxia inducible factor (HIF)-1α level. The results demonstrated that curcumin can significantly reduce DAI and spleen index scores and improve mucosal inflammation. Curcumin could also regulate the re-equilibration of Treg/Th17. IL-10 level in the colon was significantly increased, while inflammatory cytokines IL-6, IL-17 and IL-23 were significantly reduced following curcumin treatment. No significant difference in HIF-1α was observed between the colitis and the curcumin group. It was concluded that oral administration of curcumin can effectively treat experimental colitis by regulating the re-equilibration of Treg/Th17 and that the regulatory mechanism may be closely related to the IL-23/Th17 pathway. The results of the present study provided molecular insight into the mechanism by which curcumin treats ulcerative colitis.

Qingchang Huashi granule ameliorates experimental colitis via restoring the dendritic cell-mediated Th17/Treg balance

BACKGROUND

The balance between T helper 17 (Th17) cells and regulatory T cells (Tregs) is involved in immunological tolerance. Destruction of immunological tolerance by dendritic cell (DC)-mediated T cells is involved in the pathogenesis of ulcerative colitis (UC). Qingchang Huashi granule (QCHS) has been confirmed in the treatment of UC involved by inhibiting the activation of DCs. The aim of this study was to investigate the mechanism through which QCHS restores the Th17/Treg balance by modulating DCs in the treatment of UC.

METHODS

The effects of QCHS on Th17 cells, Tregs and DCs were detected in a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced experimental colitis model. Furthermore, we injected QCHS-treated DCs into colitis model to test whether QCHS modulates the Th17/Treg balance via DCs. Tregs and Th17 cells were analyzed by FACS. IL-10, IL-17, and Foxp3 were measured by ELISA, Western blot and qRT-PCR.

RESULTS

Both QCHS and QCHS-treated DCs improved colonic histopathology, diminished Th17 cell differentiation and inhibited IL-17 production while promoting CD4+CD25+Foxp3+ Treg differentiation and augmenting IL-10 and Foxp3 expression in colitis mice. Additionally, QCHS reduced CD86 and MHC-II expression on DCs, decreased IL-12 production ex vivo and restored the Th17/Treg ratio in the colitis model.

CONCLUSION

The findings of this study indicate that QCHS ameliorates TNBS-induced colitis by restoring the DC-mediated Th17/Treg balance.

Serum interleukin 17A and interleukin 17F in children with inflammatory bowel disease

Interleukin 17A (IL-17A) and interleukin 17F (IL-17F) appear to play important role in pathogenesis of some autoimmune diseases. However, their role in inflammatory bowel disease (IBD) has not been yet fully elucidated. We aimed to determine serum IL-17A and IL-17F in children with IBD and to assess their association with IBD activity. Recruited children underwent blood tests including complete blood count, C-reactive protein, erythrocyte sedimentation rate, IL-17A and IL-17F and stool sampling for calprotectin. The study group comprised 68 children with IBD, including 43 with ulcerative colitis and 25 with Crohn's disease. Control group included 20 healthy children. IL-17A was significantly increased in children with IBD (median: 10.95 pg/ml; range: 0.65-200.54 pg/ml) compared to controls (median: 4.09 pg/ml; range: 0.67-26.20 pg/ml) (p = 0.002). IL-17A was significantly increased in patients with active phase of ulcerative colitis (median: 14.58 pg/ml; range: 0.65-200.54 pg/ml) compared to those in ulcerative colitis remission (median: 8.13 pg/ml; range: 1.61-58.56 pg/ml) (p = 0.04). There were no significant differences in IL-17A among patients with active and inactive Crohn's disease (p = 0.18). IL-17F did not differ significantly between children with IBD (median: 15.11 pg/ml; range: 0.09-189.84 pg/ml) and controls (median: 11.56 pg/ml; range: 0.19-32.49 pg/ml) (p = 0.33). Our study suggests that interleukin 17A may diverse active phase from remission only in ulcerative colitis but not in Crohn's disease.

Sishen Pill Treatment of DSS-Induced Colitis via Regulating Interaction With Inflammatory Dendritic Cells and Gut Microbiota

Sishen Pill (SSP) is a typical prescription in the pharmacopeia of traditional Chinese medicine (TCM), and is usually used to treat inflammatory bowel disease (IBD). It is known that inflammatory dendritic cells (DCs) and imbalance of gut microbiota play significant roles in the pathogenesis of IBD. However, it is not clear whether SSP can treat IBD by regulating interaction of DCs and gut microbiota. In the present study, the levels of inflammatory DCs and gut microbiota were analyzed by flow cytometry and 16S rDNA analysis. SSP relieved the pathological damage to the colon of mice with colitis induced by dextran sodium sulfate (DSS). As typical indicators of inflammatory DCs, the levels of CD11c+CD103+E-cadherin+ cells and pro-inflammatory cytokines [interleukin (IL)-1β, -4, -9, and -17A] were decreased in mice with colitis treated by SSP for 10 days. Simultaneously, the gut microbiota composition was regulated, and beneficial bacteria were increased and pathogenic bacteria were reduced. The results indicated that SSP regulated the interaction between inflammatory DCs and gut microbiota to treat DSS-induced colitis.

Tryptophan Metabolism, Regulatory T Cells, and Inflammatory Bowel Disease: A Mini Review

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract resulting from the homeostasis imbalance of intestinal microenvironment, immune dysfunction, environmental and genetic factors, and so on. This disease is associated with multiple immune cells including regulatory T cells (Tregs). Tregs are a subset of T cells regulating the function of various immune cells to induce immune tolerance and maintain intestinal immune homeostasis. Tregs are correlated with the initiation and progression of IBD; therefore, strategies that affect the differentiation and function of Tregs may be promising for the prevention of IBD-associated pathology. It is worth noting that tryptophan (Trp) metabolism is effective in inducing the differentiation of Tregs through microbiota-mediated degradation and kynurenine pathway (KP), which is important for maintaining the function of Tregs. Interestingly, patients with IBD show Trp metabolism disorder in the pathological process, including changes in the concentrations of Trp and its metabolites and alteration in the activities of related catalytic enzymes. Thus, manipulation of Treg differentiation through Trp metabolism may provide a potential target for prevention of IBD. The purpose of this review is to highlight the relationship between Trp metabolism and Treg differentiation and the role of this interaction in the pathogenesis of IBD.

Role of Foxp3/Treg and RORγt/Th17 imbalance in chronic hepatitis B virus infection

A wide range of immune-mediated liver damage can be seen during infection with hepatitis B virus (HBV). Failure of HBV immune clearance leads to chronic hepatitis and greatly increases the risk of liver cirrhosis and hepatocellular carcinoma. Recently, there have been many studies on the relationship between the outcome of HBV infection and the immune status of patients. The immune response of T lymphocytes in HBV infection plays an important role, especially the imbalance of regulatory T cells (Treg)/Helper T cell 17 (Th17). The imbalance between the Treg and Th17 is an important mechanism of persistent HBV infection and inflammatory injury of the liver. To better reveal the underlying mechanisms, we systematically review the roles of Treg and Th17 and discuss the relationship between Treg and Th17 during HBV infection as well as the changes in the two related specific transcription factors, retinoid-related orphan nuclear receptor γt (RORγt) and forkhead/winged helix family transcription factor 3 (Foxp3). The research on HBV immunotargeting therapy in recent years has suggested the role of Foxp3/Treg and RORγt/Th17 imbalance in HBV infection. Such findings provide new ideas for the treatment of chronic hepatitis B.