Interaction between Ras and Bcl2L12 in B cells suppresses IL-10 expression.

The pathogenesis of recurrent tonsillitis is to be further investigated. B cell-derived interleukin (IL)-10 plays a critical role in immune regulation. Ras activation plays an important role in cancer and many immune disorders. This study aims to investigate the role of Ras activation in down regulating IL-10 expression in tonsillar B cells. Surgically removed tonsil tissues were collected from patients with recurrent acute tonsillar inflammation; B cells were isolated from the tonsillar tissues by flow cytometry sorting to be analyzed by the Ras-specific enzyme-linked immunosorbent assay and pertinent immunological approaches. We found that, compared to peripheral B cells (pBC), B cells isolated from the tonsillar tissues with recurrent inflammation (tBC) showed higher Ras activation, lower IL-10 expression and higher Bcl2L12 expression. Bcl2L12 formed a complex with GAP (GTPase activating protein) to prevent Ras from deactivating. The Ras activation triggered the MAPK/Sp1 pathway to promote the Bcl2L12 expression in B cells. Bcl2L12 prevented the IL-10 expression in tBCs, that was counteracted by inhibition of Ras or the Ras signal transduction pathway. In conclusion, Bcl2L12 interacts with Ras activation to compromise immune tolerance in the tonsils by inhibiting the IL-10 expression in tBCs. Inhibition of Bcl2L12 can restore the IL-10 expression in tBCs.

Livin in synergy with Ras induces and sustains corticosteroid resistance in the airway mucosa.

Rationale: Corticosteroid resistance (CR) seriously affects the therapeutic effects of steroids on many chronic inflammatory disorders, including airway allergy. The mechanism of CR development is unclear. Recent research indicates that livin, an apoptosis inhibitor, is associated with the regulation in cell activities. This study investigates the role of livin in the inducing and sustaining CR in the airway mucosa. Methods: Nasal epithelial cells (NECs) were isolated from surgically removed nasal mucosal tissues of patients with allergic rhinitis (AR) and nasal polyps with or without CR. Differentially expressed genes in NECs were analyzed by the RNA sequencing. A CR mouse model was developed to test the role of livin in CR development. Results: The results showed that NECs of AR patients with CR expressed high levels of livin, that was positively correlated with the thymic stromal lymphopoietin (TSLP) expression and the high Ras activation status in NECs. Livin and Ras activation mutually potentiating each other in the inducing and sustaining the TSLP expression in NECs. TSLP induced eosinophils and neutrophils to express glucocorticoid receptor-ß (GRß). Eosinophils and neutrophils with high CRß expression were resistant to corticosteroids. Depletion of livin or inhibition of TSLP markedly attenuated CR and airway allergy. Conclusions: Livin facilitates CR development in the airways by promoting TSLP expression in epithelial cells and the GRß expression in eosinophils and neutrophils. Depletion of livin or inhibiting TSLP attenuates CR development and inhibits airway allergy, this has the translational potential to be used in the treatment of airway allergy.

Twist1 sustains the apoptosis resistance in eosinophils in nasal mucosa of allergic rhinitis.

Eosinophils (Eos) are the canonical effector cells in allergic rhinitis (AR) and many inflammatory diseases. The mechanism of eosinophilia occurring in the lesion sites is not fully understood yet. Twist1 protein (Twist, in short) is an apoptosis inhibitor that also has immune regulatory functions. This study aims to investigate the role of Twist in the pathogenesis of eosinophilia in AR. In this study, surgically removed human nasal mucosal samples were obtained from patients with chronic sinusitis and nasal polyps with AR (the AR group) or without AR (the nAR group). Eos were isolated from the samples by flow cytometry. We found that abundant Eos were obtained from the surgically removed nasal mucosa tissues of both nAR and AR groups. Significantly higher Ras activation was detected in AR Eos than that in nAR Eos. Ras activation was associated with the apoptosis resistance in AR Eos. The Twist (an apoptosis inhibitor) expression was higher in AR Eos, which was positively correlated with the Ras activation status. The sensitization to IgG induced Twist expression in Eos, in which Ras activated the MAPK-HIF-1α pathway, the latter promoted the Twist gene transcription. Twist bound Rac GTPase activating protein-1 to sustain the Ras activation in Eos. Ras activation sustained the apoptosis resistance in Eos. In conclusion, high Ras activation was detected in the AR nasal mucosal tissue-isolated Eos. IgG-sensitization induced Ras activation and Twist expression in Eos, that conferred Eos the apoptosis resistance.

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.

Bcl2 like protine-12 (Bcl2L12) facilitates experimental airway allergic inflammation by inducing autocrine eotaxin in eosinophils.

BACKGROUND: The pathogenesis of airway allergic disorders (AAD) needs to be further investigated. Eosinophils (Eos) are the canonical effector cells in AAD attacks. Bcl2 like protein-12 (Bcl2L12) is an apoptosis inhibitor and an immune regulator. Eos have the defects of apoptosis. This study aims to investigate the role of Bcl2L12 in the AAD pathogenesis by regulating Eo activities. METHODS: Human nasal lavage fluids (NLF) and mouse bronchoalveolar lavage fluids (BALF) was collected. Eos in NLF and BALF were analyzed by flow cytometry. A murine AAD model was developed with ovalbumin as a specific antigen. RESULTS: We found that Eos isolated from NLF or BALF of AAD subjects expressed high levels of Bcl2L12 and showed defects of apoptosis. The Bcl2L12 expression in Eos was positively correlated with the AAD response. High lipopolysaccharide levels were detected in the AAD airways, that promoted the Bcl2L12 expression in Eos. Bcl2L12 mediated the LPS-induced autocrine eotaxin 1 expression in Eos through activating the MAPK p38/STAT6/NF-κB signal pathway. Depletion of Bcl2L12 in Eos suppressed experimental AAD in mice. CONCLUSIONS: AAD Eos express high levels of Bcl2L12, the latter is associated with AAD response by regulating the autocrine eotaxin 1 in Eos. Depletion of Bcl2L12 in Eos attenuates experimental AAD, suggesting that to suppress the Bcl2L12 Eos has the translational potential in the treatment of AAD.

Identification of antigen-specific neutrophils in the tonsils with recurrent acute inflammation.

The pathogenesis of recurrent acute tonsillitis (Rtn) is to be further investigated. Polymorphonuclear neutrophils (PMN) often associate with the pathogenesis of acute and chronic inflammation. This study aims to identify the antigen-specific PMNs (sPMNs) isolated from the tonsillar tissues with recurrent acute inflammation. In this study, CD66b+ PMNs were isolated from surgically removed tonsils (40 tonsils were from 20 Rtn patients; 24 tonsils were from 12 tonsil tumour patients) by flow cytometry cell sorting. sPMNs were identified through immunological approaches. We found that compared with the control tonsil samples (from marginal non-tumour tissues of tonsil cancer), Rtn samples showed higher PMN frequency, higher levels of myeloperoxidase (MPO) and neutrophil elastase (NE), in which positive correlation was detected between the inflammatory scores in the Rtn tissues and PMN counts (r = .7352; p = .0002), or MPO (r = .6565, p = .0017), or NE (r = .6687, p = .0013). Upon exposure to tonsillar tissue protein extracts in the culture, a portion of Rtn PMNs was activated and released inflammatory mediators. A complex of tonsillar tissue-specific IgG and FcγRI was observed on the surface of Rtn PMNs; these PMNs could specifically recognize the Rtn tissue extracts and were designated the tonsillar antigen-specific PMNs (sPMNs). A signal transduction pathway of mitogen-activated protein kinase (MAPK)-nuclear factor of T cell activation (NFAT) was activated in sPMNs after exposure to Rtn tissue extracts. In summary, a fraction of sPMN in the Rtn tonsillar tissues was identified and characterized. The sPMNs can be activated upon exposure to tonsil-specific antigens. These sPMNs may contribute to the Rtn pathogenesis.

A20-OVA Nanoparticles Inhibit Allergic Asthma in a Murine Model.

The skewed T helper (Th) 2 response plays a critical role in the pathogenesis of allergic asthma. Regulatory T (Treg) cells and the regulatory cytokines are required in maintaining the homeostasis in the body. This study aims to determine the effects of a poly(lactic-co-glycolic) acid (PLGA)-ovalbumin (OVA)+A20 (a ubiquitin E3 ligase) nanovaccine on inhibiting allergic asthma in a murine model. In this study, A20 and OVA (a model antigen) were encapsulated into PLGA to be a nanovaccine (PLGA-OVA+A20). An allergic asthma murine model was developed with OVA as the specific antigen to test the role of PLGA-OVA+A20 nanovaccine in maintaining the immune homeostasis in the airway tissues. The results showed that PLGA-OVA+A20 nanovaccine inhibited the asthma responses in mice by suppressing Th2 inflammatory responses, promoting the generation of Treg cells in the airway tissues. We conclude that the PLGA-OVA+A20 nanovaccine has a marked inhibitory effect on the airway allergic response in sensitized mice by significantly promoting the generation of Treg cell and IL-10. The data suggest that PLGA-OVA+A20 has translational potential in the treatment of allergic asthma.

Interleukin-5 induces apoptotic defects in CD4+ T cells of patients with allergic rhinitis.

T helper (Th)2 polarization plays an important role in the pathogenesis of allergic diseases; the underlying mechanism remains to be further investigated. B cell lymphoma protein-2 like protein-12 (Bcl2L12) has the anti-apoptotic function. This study aims to elucidate the contribution of Bcl2L12 to Th2 polarization in patients with allergic rhinitis (AR). In this study, human CD4+ T cells were isolated from blood samples collected from AR patients and healthy control (HC) subjects. The immune response profiles of CD4+ T cells were analyzed by immunologic approaches. The results showed that AR CD4+ T cells (CD4+ T cells collected from AR patients) showed defects of apoptosis. The expression of FasL in AR CD4+ T cells was lower than that of HC CD4+ T cells. Serum IL-5 levels were negatively correlated with the expression of FasL in AR CD4+ T cells. Exposure of CD4+ T cells to IL-5 in the culture suppressed the expression of FasL and increased the expression of Bcl2L12. IL-5 increased the levels of Bcl2L12 in CD4+ T cells, the latter bound to the FasL promoter to prevent FasL gene transcription. Inhibition of Bcl2L12 restored the apoptosis machinery in AR CD4+ T cells. In conclusion, overexpression of Bcl2L12 in CD4+ T cells compromises the apoptosis machinery; the latter can be restored by inhibition of Bcl2L12. BcL2L12 in CD4+ T cells may be a novel target for the treatment of AR and other allergic disorders.

Histone deacetylase 11 inhibits interleukin 10 in B cells of subjects with allergic rhinitis.

BACKGROUND: The interleukin (IL)-10 expression in B cells plays an important role in immune tolerance. The regulation of IL-10 expression in B cells is not fully understood yet. Tumor necrosis factor (TNF) is increased in allergic rhinitis (AR) patients. This study tests a hypothesis that TNF enhances histone deacetylase (HDAC)11 expression to inhibit the expression of IL-10 in B cells of AR patients. METHODS: Peripheral B cells were collected from healthy persons and patients with AR. The B cells were analyzed by immune assay and molecular biological approaches for the expression of IL-10. RESULTS: The expression of HDAC11 was higher in B cells of patients with AR than that in healthy persons. The expression of IL-10 in B cells was lower in AR patients than that in healthy subjects. The levels of HDAC11 in B cells were negatively correlated with the levels of IL-10. Exposure of B cells to TNF in the culture inhibited the expression of IL-10, in which HDAC11 played a critical role in the interference with the Il10 gene transcription. Inhibition of HDAC11 restored the IL-10 expression in B cells from AR patients and attenuated the experimental AR. CONCLUSION: TNF can suppress the expression of IL-10 in B cells via enhancing the expression of HDAC11. Inhibition of HDAC11 restores the IL-10 expression in B cells of AR subjects. HDAC11 may be a novel target for the treatment of AR.

Micro RNA-19a interferes with IL-10 expression in peripheral dendritic cells of patients with nasal polyposis.

The pathogenesis of nasal polyp is to be further investigated. Micro RNA (miR) plays a role in the development of allergic inflammation. Interleukin (IL)-10-producing dendritic cells (DC) have immune tolerogenic properties. This study test a hypothesis that miR-17-92 cluster is associated with suppressing IL-10 in peripheral DC. In this study, peripheral blood samples were obtained from 26 patients with nasal polyp. The CD11c DCs were isolated from the blood samples and analyzed for the expression of IL-10. We observed that, as compared with healthy subjects, the IL-10 expression in peripheral DC was significantly lower in polyp patients. The levels of miR-19a, but not the rest 5 members of the miR-17-92 cluster, were markedly higher in DCs in polyp group. Exposure to recombinant IL-4 suppressed the IL-10 expression in DCs, which was abolished by blocking histone deacetylase-11 or knocking down the miR-19a gene in DCs. We conclude that miR-19a plays a critical role in the suppression of IL-10 in peripheral DCs, which may be a target in the immune therapy for nasal polyp.