Human epithelial cells stimulated with Vibrio cholerae produce thymic stromal lymphopoietin and promote dendritic cell-mediated inflammatory Th2 response

Combination therapy with probiotics and anti-PD-L1 antibody synergistically ameliorates sepsis in mouse model

The study investigated the protective effects and mechanisms of probiotics in conjunction with an anti-PD-L1 antibody on the immune functions of septic mice. Sixty-four mice were assigned to sepsis groups receiving vehicle, probiotics, and anti-PD-L1 antibody individually or in combination, with healthy mice as controls. Sepsis was induced by cecal ligation and puncture (CLP), followed by intraperitoneal Lipopolysaccharide (LPS) injection. Blood and tissues were collected one day post-injection for detecting inflammation-related cytokines, Treg, PI3K/Akt pathway-related protein expression, and lung tissue pathology. The survival time of the remaining ten mice was recorded over seven days. Compared to healthy mice, septic mice given PBS exhibited significantly different serum levels of IL-6, IL-8, IL-17, IL-10, and IFN-γ (all p < 0.001). Treatment with anti-PD-L1 antibody combined with probiotics significantly increased the 7-day survival rate in septic mice, accompanied by decreased pro-inflammatory cytokines, increased anti-inflammatory cytokines, improved oxidative stress, reduced lung injury, and enhanced Th17/Treg balance. This combined therapy demonstrated superior efficacy compared to antibodies or probiotics alone. Additionally, it facilitated peripheral blood polymorphonuclear neutrophil apoptosis, enhancing protection by blocking PD-L1 function and inhibiting PI3K-dependent AKT phosphorylation. In conclusion, combining probiotics with an anti-PD-L1 antibody enhances protective effects in septic mice by reducing serum inflammatory factors, promoting neutrophil apoptosis, regulating Th17/Treg balance, and inhibiting the PI3K/Akt pathway.

Thymic stromal lymphopoietin participates in the host response to intra-amniotic inflammation leading to preterm labor and birth

The aim of this study was to establish the role of thymic stromal lymphopoietin (TSLP) in the intra-amniotic host response of women with spontaneous preterm labor (sPTL) and birth. Amniotic fluid and chorioamniotic membranes (CAM) were collected from women with sPTL who delivered at term (n = 30) or preterm without intra-amniotic inflammation (n = 34), with sterile intra-amniotic inflammation (SIAI, n = 27), or with intra-amniotic infection (IAI, n = 17). Amnion epithelial cells (AEC), Ureaplasma parvum, and Sneathia spp. were also utilized. The expression of TSLP, TSLPR, and IL-7Rα was evaluated in amniotic fluid or CAM by RT-qPCR and/or immunoassays. AEC co-cultured with Ureaplasma parvum or Sneathia spp. were evaluated for TSLP expression by immunofluorescence and/or RT-qPCR. Our data show that TSLP was elevated in amniotic fluid of women with SIAI or IAI and expressed by the CAM. TSLPR and IL-7Rα had detectable gene and protein expression in the CAM; yet, CRLF2 was specifically elevated with IAI. While TSLP localized to all layers of the CAM and increased with SIAI or IAI, TSLPR and IL-7Rα were minimal and became most apparent with IAI. Co-culture experiments indicated that Ureaplasma parvum and Sneathia spp. differentially upregulated TSLP expression in AEC. Together, these findings indicate that TSLP is a central component of the intra-amniotic host response during sPTL.

Against NF-κB/thymic stromal lymphopoietin signaling pathway, catechin alleviates the inflammation in allergic rhinitis

BACKGROUND

The prevalence of allergic rhinitis has risen sharply. Previous work has demonstrated the anti-inflammatory effect of catechin, including in models of allergic disease. However, the molecular mechanisms underlying this therapeutic effect remain unclear. Thymic stromal lymphopoietin(TSLP), as a molecule from epithelial cell, has been identified that plays a significant role in the development of allergic disease, and the production of TSLP is related to activation of the NF-κB signaling pathway. For that, we try to research the treatment of catechin for allergic rhinitis and found out possible mechanism under this effect, which was based on TSLP factor.

MATERIALS AND METHODS

Here, the anti-inflammatory effects of catechin were studied in an ovalbumin-induced allergic rhinitis murine model and a vitro experiments using poly(I:C)-stimulated human nasal epithelial cells(HNEpCs). The pharmacological effects of catechin in allergic rhinitis mice were assessed by observing the allergic symptoms, performing hematoxylin and eosin staining and Giemsa staining of the nasal tissues. Additionally, the TSLP expression in epithelial cells was tested by enzyme-linked immunosorbent assays, immunohistochemistry, and western blots. The serum levels of interleukin-5, interleukin-13, and ovalbumin-specific immunoglobulin-E were detected by enzyme-linked immunosorbent assays, and the balance between T helper type 1 and T helper type 2 cells was assessed by flow cytometry. The expression levels of phospho-NF-κBp65, IκBα, and NF-κBp65 proteins were further investigated by western blots or immunofluorescence.

RESULTS

Our results reveal that catechin, in doses of 75, 150, or 300 mg/kg, remitted the allergic symptoms in mice with allergic rhinitis, like sneezing and nasal rubbing. Catechin could reduce the levels of interleukin-5, interleukin-13, and ovalbumin-specific immunoglobulin-E in the serum and restored the T helper type 2/T helper type 1 cell balance and also had anti-thymic stromal lymphopoietin effects. Moreover, as an upstream regulator of TSLP, the NF-κB signal pathway was also suppressed after catechin treatment, which was demonstrated by the observed decrease in phospho-NF-κBp65 and NF-κBp65 levels and the reduction of IκBα degradation and NF-κBp65 nuclear translocation.

CONCLUSIONS

Catechin effectively reduced the inflammation in allergic rhinitis. The underlying mechanism is that catechin inhibited the expression of TSLP in epithelial cells by influencing NF-κB/TSLP pathway.

Analysis of the Human Mucosal Response to Cholera Reveals Sustained Activation of Innate Immune Signaling Pathways

To better understand the innate immune response to Vibrio cholerae infection, we tracked gene expression in the duodenal mucosa of 11 Bangladeshi adults with cholera, using biopsy specimens obtained immediately after rehydration and 30 and 180 days later. We identified differentially expressed genes and performed an analysis to predict differentially regulated pathways and upstream regulators. During acute cholera, there was a broad increase in the expression of genes associated with innate immunity, including activation of the NF-κB, mitogen-activated protein kinase (MAPK), and Toll-like receptor (TLR)-mediated signaling pathways, which, unexpectedly, persisted even 30 days after infection. Focusing on early differences in gene expression, we identified 37 genes that were differentially expressed on days 2 and 30 across the 11 participants. These genes included the endosomal Toll-like receptor gene TLR8, which was expressed in lamina propria cells. Underscoring a potential role for endosomal TLR-mediated signaling in vivo, our pathway analysis found that interferon regulatory factor 7 and beta 1 and alpha 2 interferons were among the top upstream regulators activated during cholera. Among the innate immune effectors, we found that the gene for DUOX2, an NADPH oxidase involved in the maintenance of intestinal homeostasis, was upregulated in intestinal epithelial cells during cholera. Notably, the observed increases in DUOX2 and TLR8 expression were also modeled in vitro when Caco-2 or THP-1 cells, respectively, were stimulated with live V. cholerae but not with heat-killed organisms or cholera toxin alone. These previously unidentified features of the innate immune response to V. cholerae extend our understanding of the mucosal immune signaling pathways and effectors activated in vivo following cholera.

TSLP production by dendritic cells is modulated by IL-1β and components of the endoplasmic reticulum stress response

Thymic stromal lymphopoietin (TSLP) produced by epithelial cells acts on dendritic cells (DCs) to drive differentiation of T_H2‐cells, and is therefore important in allergic disease pathogenesis. However, DCs themselves make significant amounts of TSLP in response to microbial products, but little is known about the key downstream signals that induce and modulate this TSLP secretion from human DCs. We show that human monocyte derived DC (mDC) secretion of TSLP in response to Candida albicans and β‐glucans requires dectin‐1, Syk, NF‐κB, and p38 MAPK signaling. In addition, TSLP production by mDCs is greatly enhanced by IL‐1β, but not TNF‐α, in contrast to epithelial cells. Furthermore, TSLP secretion is significantly increased by signals emanating from the endoplasmic reticulum (ER) stress response, specifically the unfolded protein response sensors, inositol‐requiring transmembrane kinase/endonuclease 1 and protein kinase R‐like ER kinase, which are activated by dectin‐1 stimulation. Thus, TSLP production by mDCs requires the integration of signals from dectin‐1, the IL‐1 receptor, and ER stress signaling pathways. Autocrine TSLP production is likely to play a role in mDC‐controlled immune responses at sites removed from epithelial cell production of the cytokine, such as lymphoid tissue.

Effect of camel milk on thymus and activation-regulated chemokine in autistic children: double-blind study

BACKGROUND

This study aimed to investigate the role of the effectiveness of camel milk (CM) (raw and boiled) on thymus and activation-regulated chemokine (TARC) serum levels and childhood autism rating scale (CARS) score in subjects with autism and compared to placebo group (cow milk).

METHODS

Forty-five subjects diagnosed with autism were randomly assigned to receive boiled CM for group I (n = 15), raw CM for group II (n = 15), and placebo for group III (n = 15) for 2 wk. Measures included changes in professionally completed CARS score and blood samples for TARC serum level were taken before and after milk consumption of 500 ml per day in children's regular daily diet.

RESULTS

The serum levels of TARC decreased significantly (P = 0.004) in boiled CM and in raw CM group (P = 0.01) too, but no effect was observed (P = 0.68) in placebo group. Furthermore, significant improvements were observed in CARS score (P = 0.04) in raw CM group only. There were no significant relationships between the serum of TARC level and the CARS score, age, or gender for any group.

CONCLUSION

CM administered for 2 wk significantly improved clinical measurements of autism severity and decreased serum level of TARC in autistic children, but subsequent studies are recommended.

Immune-epithelial crosstalk at the intestinal surface

The intestinal tract is one of the most complex organs of the human body. It has to exercise various functions including food and water absorption, as well as barrier and immune regulation. These functions affect not only the gut itself, but influence the overall health of the organism. Diseases involving the gastrointestinal tract such as inflammatory bowel disease and colorectal cancer therefore severely affect the patient's quality of life and can become life-threatening. Intestinal epithelial cells (IECs) play an important role in intestinal inflammation, infection, and cancer development. IECs not only constitute the first barrier in the gut against the lumen, they also constantly signal information about the gut lumen to immune cells, thereby influencing their behaviour. In contrast, by producing various antimicrobial peptides, IECs shape the microbial community within the gut. IECs also respond to cytokines and other mediators of immune cells in the lamina propria. Interactions between epithelial cells and immune cells in the intestine are responsible for gut homeostasis, and modulations of this crosstalk have been reported in studies of gut diseases. This review discusses the wide field of immune-epithelial interactions and shows the importance of immune-epithelial crosstalk in the intestine to gut homeostasis and the overall health status.

Plasmacytoid DCs, exposed to TSLP in synergy with TLR ligands, acquire significant potential towards Th2 polarization

Background

Thymic stromal lymphopoietin (TSLP) has been reported to activate myeloid dendritic cells (mDCs) to induce Th2 T lymphocyte responses. Its effect on plasmacytoid dendritic cells (pDCs) with TLR ligands has not yet been studied. We investigated the effects of TSLP and TLR ligands on mDCs and pDCs subsets.

Material/Methods

Myeloid dendritic cells (mDC) and plasmacytoid dendritic cells (pDC) were stimulated by TLR ligands (mDC with TLR1/2 LTA, TLR2 PGN, TLR3 poly I: C, TLR4 LPS, TLR5 Flagellin) (pDC with TLR9 CpG2006, CpG 2216, TLR7 loxoribine) in the presence or absence of TSLP. Supernatants from mDCs and pDCs were analyzed for cytokine production. mDCs and pDCs were collected and cultured with allogeneic naïve T cells and after 7 days of co-culture. DC-primed CD4+ T cells were washed and restimulated with PMA and ionomycin. Cytokine production in supernatants from restimulated cells - IL-4, IL-5, IL-10, IL-13, TNF-α was analyzed by Luminex.

Results

TSLP alone induced the expression of maturation markers on mDCs and increased their ability to polarize lymphocytes into the Th2 phenotype. We demonstrated that pDCs also have the capacity to become even more potent inducers of Th2 immune responses, but only after combined treatment with TSLP and TLR ligands, particularly with TLR9 ligand CpG 2006.

Conclusions

TSLP plays a major role in Th2 polarization of immune response mediated by myeloid DCs. Here, we demonstrate that plasmacytoid DCs, exposed to TSLP together with TLR ligands, acquire significant potential towards Th2 polarization.

Elevated serum levels of macrophage-derived chemokine and thymus and activation-regulated chemokine in autistic children

Background

In some autistic children, there is an imbalance of T helper (Th)1/Th2 lymphocytes toward Th2, which may be responsible for the induction of the production of autoantibodies in these children. Th2 lymphocytes express CCR4 receptors. CCR4 ligands include macrophage-derived chemokine (MDC) and thymus and activation-regulated chemokine (TARC). They direct trafficking and recruitment of Th2 cells. We are the first to measure serum levels of CCR4 ligands in relation to the degree of the severity of autism.

Methods

Serum concentrations of MDC and TARC were measured, by quantitative sandwich enzyme immunoassay technique, in 56 autistic children and 32 healthy matched children.

Results

Autistic children had significantly higher serum levels of MDC and TARC than healthy controls (P <0.001 and P <0.001, respectively). Children with severe autism had significantly higher serum levels of MDC and TARC than patients with mild to moderate autism (P <0.001 and P = 0.01, respectively). In addition, there were significant positive correlations between CARS and serum levels of both MDC (P <0.001) and TARC (P <0.001) in children with autism. There were significant positive correlations between serum levels of MDC and TARC in autistic children (P <0.001).

Conclusions

Serum levels of CCR4 ligands were elevated in autistic children and they were significantly correlated to the degree of the severity of autism. However, further research is warranted to determine the pathogenic role of CCR4 ligands in autism and to shed light on the therapeutic role of CCR4-ligand antagonism in autistic children.

Innate immune responses in house dust mite allergy

Sensitizations to house dust mites (HDM) trigger strong exacerbated allergen-induced inflammation of the skin and airways mucosa from atopic subjects resulting in atopic dermatitis as well as allergic rhinitis and asthma. Initially, the Th2-biased HDM allergic response was considered to be mediated only by allergen B- and T-cell epitopes to promote allergen-specific IgE production as well as IL-4, IL-5, and IL-13 to recruit inflammatory cells. But this general molecular model of HDM allergenicity must be revisited as a growing literature suggests that stimulations of innate immune activation pathways by HDM allergens offer new answers to the following question: what makes an HDM allergen an allergen? Indeed, HDM is a carrier not only for allergenic proteins but also microbial adjuvant compounds, both of which are able to stimulate innate signaling pathways leading to allergy. This paper will describe the multiple ways used by HDM allergens together with microbial compounds to control the initiation of the allergic response through engagement of innate immunity.

Vibrio cholerae O395 outer membrane vesicles modulate intestinal epithelial cells in a NOD1 protein-dependent manner and induce dendritic cell-mediated Th2/Th17 cell responses

Like other Gram-negative pathogens, Vibrio cholerae, the causative agent of the diarrheal disease cholera, secretes outer membrane vesicles (OMVs). OMVs are complex entities composed of a subset of envelope lipid and protein components and play a role in the delivery of effector molecules to host cells. We previously showed that V. cholerae O395 cells secrete OMVs that are internalized by host cells, but their role in pathogenesis has not been well elucidated. In the present study, we evaluated the interaction of OMVs with intestinal epithelial cells. These vesicles induced expression of proinflammatory cytokines such as IL-8 and GM-CSF and chemokines such as CCL2, CCL20, and thymic stromal lymphopoietin in epithelial cells through activation of MAPK and NF-κB pathways in NOD1-dependent manner. Epithelial cells stimulated with OMVs activated dendritic cells (DCs) in a direct co-culture system. Activated DCs expressed high levels of co-stimulatory molecules; released inflammatory cytokines IL-1β, IL-6, TNF-α, and IL-23 and chemokines CCL22 and CCL17; and subsequently primed CD4(+) T cells leading to IL-4, IL-13, and IL-17 expression. These results suggest that V. cholerae O395 OMVs modulate the epithelial proinflammatory response and activate DCs, which promote T cell polarization toward an inflammatory Th2/Th17 response.