The transcription factor XBP1 in dendritic cells promotes the TH2 cell response in airway allergy.

Dendritic cells (DCs) that express T cell immunoglobulin domain molecule-4 (TIM4), a cell surface receptor for phosphatidylserine, induce T helper 2 (TH2) cell responses and allergic reactions. We elucidated the role of the transcription factor X-box-binding protein-1 (XBP1) in the induction of the TH2 cell response through its role in generating TIM4+ DCs. We found that XBP1 was required for TIM4 mRNA and protein expression in airway DCs in response to the cytokine interleukin-2 (IL-2) and that this pathway was required for TIM4 expression on DCs in response to the allergens PM2.5 and Derf1. The IL-2-XBP1-TIM4 axis in DCs contributed to Derf1/PM2.5-induced, aberrant TH2 cell responses in vivo. An interaction between the guanine nucleotide exchange factor Son of sevenless-1 (SOS1) and the GTPase RAS promoted XBP1 and TIM4 production in DCs. Targeting the XBP1-TIM4 pathway in DCs prevented or alleviated experimental airway allergy. Together, these data suggest that XBP1 is required for TH2 cell responses by inducing the development of TIM4+ DCs, which depends on the IL-2-XBP1-SOS1 axis. This signaling pathway provides potential therapeutic targets for the treatment of TH2 cell-dependent inflammation or allergic diseases.

T cell activator-carrying extracellular vesicles induce antigen-specific regulatory T cells.

The mechanism of antigen-specific regulatory T cell (Treg ) induction is not yet fully understood. Curcumin has an immune regulatory function. This study aims to induce antigen-specific Tregs by employing extracellular vesicles (EVs) that carry two types of T cell activators. Two types of T cell activators, ovalbumin (OVA)/major histocompatibility complex-II (MHC-II) and tetramethylcurcumin (FLLL31) (a curcumin analog) were carried by dendritic cell-derived extracellular vesicles, designated OFexo. A murine model of allergic rhinitis (AR) was developed with OVA as the specific antigen. AR mice were treated with a nasal instillation containing OFexo. We observed that OFexo recognized antigen-specific T cell receptors (TCR) on CD4+ T cells and enhanced Il10 gene transcription in CD4+ T cells. Administration of the OFexo-containing nasal instillation induced antigen-specific type 1 Tregs (Tr1 cells) in the mouse airway tissues. OFexo-induced Tr1 cells showed immune suppressive functions on CD4+ T cell proliferation. Administration of OFexo efficiently alleviated experimental AR in mice. In conclusion, OFexo can induce antigen-specific Tr1 cells that can efficiently alleviate experimental AR. The results suggest that OFexo has the translational potential to be employed for the treatment of AR or other allergic disorders.

Modulating oxidative stress counteracts specific antigen-induced regulatory T-cell apoptosis in mice.

Treg are known to have a central role in orchestrating immune responses, but less is known about the destiny of Treg after being activated by specific Ags. This study aimed to investigate the role of superoxide dismutase, an active molecule in the regulation of oxidative stress in the body, in the prevention of Treg apoptosis induced by specific Ags. Ag-specific Tregs were isolated from the DO11.10 mouse intestine. A food allergy mouse model was developed with ovalbumin as the specific Ag and here, we observed that exposure to specific Ag induced Treg apoptosis through converting the precursor of TGF-ß to its mature form inside the Tregs. Oxidative stress was induced in Tregs upon exposure to specific Ags, in which Smad3 bound the latency-associated peptide to induce its degradation, converting the TGF-ß precursor to its mature form, TGF-ß. Suppressing oxidative stress in Tregs alleviated the specific Ag-induced Treg apoptosis in in vitro experiments and suppressed experimental food allergy by preventing the specific Ag-induced Treg apoptosis in the intestine. In conclusion, exposure to specific Ags induces Treg apoptosis and it can be prevented by upregulating superoxide dismutase or suppressing reactive oxidative species in Tregs.

Dust-mite-derived protein disulfide isomerase suppresses airway allergy by inducing tolerogenic dendritic cells.

House dust mites (HDMs) are a potent allergen source that are commonly found in human living environments. While HDMs are known to induce allergic diseases in humans, such as asthma, its other biological activities related to human health are less understood. Our laboratory recently purified the HDM protein PDI (protein disulfide isomerase). In this study, we assess the role of PDI in contributing to immune regulation. Using mass spectrometry, we analyzed the complexes of DEC205 and HDM extracts, and the role of PDI in the induction of tolerogenic dendritic cells (DCs) was assessed in human cell culture experiments and verified in a murine model. We found that more than 20 HDM-derived proteins, including PDI, bound to DCs by forming complexes with DEC205. Additionally, DEC205-mediated the endocytosis of PDI. HDM-derived PDI (HDM-PDI) promoted Foxp3 expression in DCs. HDM-PDI-primed DCs also showed tolerogenic properties that induced regulatory T cell development, indicating that the primed DCs were tolerogenic DCs. Our results suggested that the PDI/DEC205/TIEG1/Foxp3 signal pathway activation was involved in the HDM-PDI-induced Foxp3 expression in DCs. Finally, we found that HDM-PDI competitively counteracted the Th2 cytokines to restore DC's tolerogenicity, and administration of HDM-PDI could suppress experimental asthma. In conclusion, our data suggest that HDM-PDI contributes to immune regulation by inducing tolerogenic DC development. Administration of HDM-PDI can alleviate experimental asthma. These findings demonstrate that HDM-PDI has translational potential to be used in the treatment of immune disorders such as asthma.

Chimeric antigen-guiding extracellular vesicles eliminate antigen-specific Th2 cells in subjects with food allergy.

BACKGROUND: Antigen (Ag)-specific T helper (Th)2 cells play a central role in food allergy (FA) pathogenesis. Methods can be used to eliminate Ag-specific Th2 cells that are currently lacking. This study aims to eliminate the Ag-specific Th2 cells with a novel nanoparticle, the mEV (modified extracellular vesicles, that carry a chimeric antigen peptide, MHC II and caspase 3) in a murine FA model. METHODS: mEVs were generated by exposing dendritic cells (DC) to ovalbumin (OVA, a specific Ag) and recombinant caspase 3 (Casp3) in the culture overnight. Exosomes were purified from culture supernatant by the magnetic antibody approach. A murine FA model was developed with OVA as the specific Ag. RESULTS: Purified mEVs had the molecular markers of extracellular vesicle, CD81, CD63, and CD9, cleaved Casp3 and MHC II/OVA complexes. mEVs specifically bound to the surface of Ag-specific CD4+ T cells, induced Ag-specific CD4+ T cell apoptosis both in vitro and in vivo as well as increased regulatory T cells in the intestinal tissues. Administration of mEV efficiently suppressed experimental FA. CONCLUSIONS: mEVs carry Ag/MHC II complexes and Casp3, that can induce Ag-specific Th2 cell apoptosis. Administration of mEV can efficiently suppress experimental FA. The results suggest that the mEVs have the translational potential to be used in the treatment of FA and other allergic diseases.

Epithelial cell-derived CD83 restores immune tolerance in the airway mucosa by inducing regulatory T-cell differentiation.

The mechanism of generation of regulatory T cells (Treg) remains incompletely understood. Recent studies show that CD83 has immune regulatory functions. This study aims to investigate the role of epithelial cell-derived CD83 in the restoration of immune tolerance in the airway mucosa by inducing the Treg differentiation. In this study, CD83 and ovalbumin (OVA)-carrying exosomes were generated from airway epithelial cells. An airway allergy mouse model was developed to test the role of CD83/OVA-carrying exosomes in the suppression of airway allergy by inducing Treg generation. We observed that mouse airway epithelial cells expressed CD83 that could be up-regulated by CD40 ligand. The CD83 deficiency in epithelial cells retarded the Treg generation in the airway mucosa. CD83 up-regulated transforming growth factor-ß-inducible early gene 1 expression in CD4+ T cells to promote Foxp3 expression. Exposure of primed CD4+ T cells to CD83/OVA-carrying exosomes promoted antigen-specific Treg generation. Administration of CD83/OVA-carrying exosomes inhibited experimental airway allergic response. In summary, airway epithelial cells express CD83 that is required in the Treg differentiation in the airway mucosa. Administration of CD83/OVA-carrying exosomes can inhibit airway allergy that has the translation potential in the treatment of airway allergic disorders.

Integrin αvß6 cooperates with resiquimod to restore antigen-specific immune tolerance in airway allergy.

BACKGROUND: Integrin αvß6 can convert the transforming growth factor (TGF)-ß precursor to the mature form. Resiquimod (R848) can generate TGF-ß-producing regulatory T cells (Treg). Thus, to concurrent administration of specific antigen and R848 may generate antigen-specific Tregs, that is expected to restore immune tolerance in subjects with airway allergic diseases (AAD). METHODS: A bio-nanoparticle, designated Rexo, containing an antigen/MHC II complex and R848, was naturally assembled in dendritic cells, that was released as an exosome. An AAD mouse model was developed used to test the effects of Rexo on restoring the immune tolerance in the airways. RESULTS: Exposure to R848 failed to induce Tregs in the ß6-deficient mouse airway tissues, that were successfully induced in wild type mice. The results were validated inin vitro experiments. R848 activated the TLR7/MyD88/p38 signal pathway to increase the αvß6 levels in CD4+ T cells, the αvß6 then converted the TGF-ß precursor to its mature form, and thus, induced Treg generation. Administration of Rexo restored the antigen-specific immune tolerance in the airways manifesting efficiently suppressing experimental AAD by inducing antigen-specific Tregs in the airways and inhibiting antigen-specific Th2 response. CONCLUSIONS: Rexos can inhibit experimental AAD via inducing antigen-specific Tregs to restore immune tolerance in the airway tissues, suggesting that Rexos have the translational potential to be used in the treatment of AAD.

FcγRI plays a critical role in patients with ulcerative colitis relapse.

Ulcerative colitis (UC) is a disease that frequently relapses and affects more than 0.1% general population; the underlying mechanism is poorly understood. Published data show that polymorphonuclear neutrophils (PMN) contribute to the pathogenesis of UC. This study aims to identify antigen (Ag)-specific PMNs and investigate their role in UC relapse. In this study, the correlation between PMN activities and UC relapse was assessed in a group of UC patients. A UC mouse model was developed to expand the findings of UC patient study. The results showed that a positive correlation was detected between the high PMN activities and the food Ag-specific IgG amounts in colon biopsies of UC patients. UC patient-derived Ag-specific PMNs could be activated upon exposure to food specific Ag. The Ag/FcγRI complexes were detected on the surface of PMNs in UC patients. Re-exposure of sensitized PMNs to specific Ag triggered PMN activation and induced UC-like inflammation in the mouse colon. We conclude that FcγRI plays a critical role in UC relapse. Inhibition of FcγRI can efficiently inhibits experimental UC.

Specific antigen-guiding exosomes inhibit food allergies by inducing regulatory T cells.

The therapies for food allergy (FA) need to be improved. The generation of inducible regulatory T cells (Tregs) can support immune tolerance in the body. This study aims to suppress experimental FA by inducing Tregs through the employment of modified exosomes (mExosomes). In this study, mExosomes were prepared by incubating dendritic cells with interleukin (IL)-2 and ovalbumin (OVA, used as a specific antigen) in the culture. Exosomes were purified from culture supernatant and used as the mExosomes. A murine FA model was developed to test the effects of mExosomes on the generation of Tregs in the mouse intestinal tissues and inhibiting FA. The results showed that mExosomes, which carried IL-2 and a complex of OVA peptide-major histocompatibility complex class II on the surface of exosomes, bound to OVA-specific CD4+ T cells and induced CD4+ T cells to differentiate into Tregs. In the FA mouse intestinal tissues, we found low IL-2 levels that were positively correlated with the number of Tregs. Depletion of IL-2 in mice prevented the generation of Tregs. The levels of peroxisome proliferator-activated receptor-γ were increased in the FA intestinal tissues with inhibited IL-2 production. Administration of mExosomes induced Tregs in the intestinal tissues and efficiently suppressed FA in mice. We conclude that the mExosomes can suppress FA in mice through inducing Tregs. The data suggest that the mExosomes have translational potential in the treatment of FA and other allergic disorders.

Association between tumor necrosis factor-α -308 Gauss/A polymorphism and risk of silicosis and coal workers pneumoconiosis in Chinese population.

BACKGROUND: Many studies have attempted to clarify the association between TNF-a -308G/A polymorphism and pneumoconiosis, but there has been no definite consensus to date. To further assess the effects of TNF-a -308G/A polymorphism on the risk of pneumoconiosis, a meta-analysis was performed in Chinese population. METHODS: We searched the related literature in PubMed and Chinese databases through June 2018. The strength of the associations was assessed used pooled odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Nine case-control studies including 730 silicosis cases, 457 coal workers pneumoconiosis cases and 2429 controls were identified according to the inclusion criteria. In the total analyses, a significantly elevated risk was found in allelic model (OR = 1.41, 95% CI = 1.16-1.71). In the subgroup analyses by geographic area and type of pneumoconiosis, significant results were found both in North China (A versus G, OR = 1.33, CI = 1.05-1.69) and South China (A versus G, OR = 1.56, CI = 1.14-2.15); significant results were also found in silicosis (A versus G, OR = 1.40, CI = 1.11-1.78) and coal worker pneumoconiosis (A versus G, OR = 1.42, CI = 1.03-1.96). CONCLUSION: This meta-analysis suggested that TNF-a gene -308 G/A polymorphism is associated with increased silicosis and coal workers pneumoconiosis risk in the Chinese population, and further studies in other ethnic groups are required for definite conclusions.

The 3-methyl-4-nitrophenol (PNMC) compromises airway epithelial barrier function.

BACKGROUND AND AIMS: It is recognized that the air pollution is associated with the pathogenesis of airway diseases. This study aims to elucidate the role of the 3-methyl-4-nitrophenol (PNMC), one of the components of diesel-exhaust particles, in compromising the airway epithelial barrier integrity. METHODS: A549 cells, an airway epithelial cell line, were cultured to monolayers to be used as an in vitro epithelial barrier model. BALB/c mice were treated with nasal drops containing PNMC to test the effects of PNMC on alternating the airway epithelial barrier functions. RESULTS: Exposure of mice to PNMC induced nasal epithelial cell apoptosis and increased the permeability of the nasal epithelial barrier. PNMC increased casp8 and casp3 activities in nasal epithelial cells. Exposure to PNMC up regulated Fas and FasL expression in airway epithelial cells. Inhibition of caspase abolished the PNMC-induced airway epithelial barrier dysfunction. CONCLUSION: Exposure of airway mucosa to PNMC induces epithelial cell apoptosis and compromises the epithelial barrier function, which can be prevented by the inhibition of caspases.

[Effects of diterpene phenol extract of Rosmarinus officinalis on TGFbeta1 and mRNA expressions of its signaling pathway molecules in the lung tissue of pulmonary fibrosis rats].

OBJECTIVE: To investigate the regulative mechanism of the diterpene phenol extract of Rosmarinus Officinalis (DERO) on the imbalance of collagen metabolism of the lung tissue in pulmonary fibrosis rats. METHODS: Fifty healthy Sprague-Dawley rats were randomly divided into the normal saline group (NS), the bleomycin-induced lung injury group (BLM), the low dose DERO group (at the daily dose of 50 mg/kg), the moderate dose DERO group (at the daily dose of 100 mg/kg), and the high dose DERO group (at the daily dose of 200 mg/kg), 10 in each group (abbreviated as DERO 1, 2, 3, respectively). The pulmonary fibrosis rat model was prepared by disposable intratracheal instillation of bleomycin. DERO was administered by gastrogavage as intervention during the repairing process of lung injury. On the morning of the 29th day, the rats' lung tissue was extracted. The karyocyte number, collagen protein, type I collagen (collagen I) and transforming growth factor-beta type II receptor (TGFbetaR II), Smad4 mRNA expressions were semi-quantitatively determined using tissue microarray, HE staining, collagen fiber dyeing, immunohistochemical assay, and in situ hybridization. Using real-time fluorescent quantification RT-PCR, the mRNA expression of transforming growth factor-beta1 (TGF-beta1) were detected. RESULTS: Compared with the NS group, the collagen deposition of the lung tissue was obvious and the inflammatory infiltration was more severe in the BLM group (P < 0.05, P < 0.01). There was no statistical difference in the aforesaid 4 indices between the DERO1 group and the BLM group (P > 0.05). The collagen deposition and the inflammatory infiltration were obviously alleviated in the DERO2 and DERO3 groups (P < 0.05, P < 0.01). Compared with the NS group, the mRNA expressions of collagen-I, TGF-beta1 R II, Smad4, and TGF-beta1 were obviously up-regulated in the BLM group (P < 0.05, P < 0.01). Compared with the BLM group, the aforesaid four indices were not statistically changed in the DERO1 group (P > 0.05). But the mRNA expressions of collagen-I, TGF-beta1 R II, Smad4, and TGF-beta1 were obviously downregulated in the DERO2 and DERO3 groups (P < 0.05, P < 0.01). But the down-regulation of Smad4 expression was not obvious in the DERO2 and the DERO3 groups (P > 0.05). Compared with the DERO1 group, the mRNA expressions of collagen-I, TGF-beta1, R II, TGFbeta1 were all obviously lower in the DERO2 and the DERO3 groups (P < 0.05). But there was no statistical difference in the aforesaid 4 indices between the DERO2 group and the DERO3 group (P > 0.05). CONCLUSIONS: DERO could regulate imbalanced collagen metabolism of pulmonary fibrosis. It could inhibit excessive deposition of collagen fibers, especially excessive deposition of collagen- I. Its mechanisms might be realized by inhibiting up-regulation of TGF-beta1 and TGFbetaR II mRNA expressions, thus interfering the activation of TGF-beta-Smad signaling pathway on target genes, especially on type I procollagen target gene.

[Effect of dragon's blood on TGF-beta/smads signal transduction molecule mRNA expression in the lung tissue of rats with pulmonary fibrosis].

OBJECTIVE: To investigate the effect of Dragon's Blood on the expression of TGF-beta signal transduction molecule TGFbetaR II or Smad4 mRNA in the lung tissue of rats with pulmonary fibrosis, and to evaluate the effect and its mechanism of Dragon's Blood on pulmonary fibrosis. METHODS: 30 SD rats were randomly divided into three groups: fibrosis model, treatment and normal control groups. In model group and treatment group, the pulmonary fibrous tissues were induced to form with the intratracheal injection of bleomycin (5 mg/kg). In normal control group, saline was given intratracheally. Dragon's Blood was administered intragastricly in treatment group with a dose of 180 mg/kg diluted in 2 mL saline while saline was given intragastricly to other two groups with same volume from day 2 till day 28 after modeling. All rats were sacrificed on the 29th day. The rat lung histopathology was examined with HE staining. In situ hybridization was used to detect the expressions of TGFbetaR II and Smad4 mRNAs in lung tissue, and the expression of collagen fibril I was examined by an immunohistochemical staining. RESULTS: The inflammation cell counting in treatment group (12913.78 +/- 5640.12) was significant lower than that in model group (22243.60 +/- 5011.55, P < 0.01). The expression of pulmonary TGF/betaR II mRNA in treatment group was significant lower than that in model group (P < 0.01). In the Smad4 mRNA expression of lung tissue, there was no significant difference occurring between treatment group and model group (P > 0.05). The expression of collagen fibril I in the lung tissue of rats in treatment group was significant lower than that in model group (P < 0. 01). CONCLUSION: Dragon's Blood can effectively reduce rats' pulmonary fibrosis, of which the mechanisms may be to inhibit the expression of TGFbetaR II mRNA in the lung tissue and thus to have the preventive effect on the excessive deposit of collagen fibril I.