Characterization of the immune suppressive functions of eosinophils.

Eosinophils account for a significant portion of immune cells in the body. It is well known that eosinophils play a role in the pathogenesis of many diseases. In which the interaction between eosinophils and other immune cells is incompletely understood. The aim of this study is to characterize the immune suppressive functions of eosinophils. In this study, an irway allergy mouse model was established. Eosinophils were isolated from the airway tissues using flow cytometry cell sorting. The RAW264.7 cell line was used to test the immune suppressive functions of eosinophils. We observed that eosinophils had immune suppressive functions manifesting inhibiting immune cell proliferation and cytokine release from other immune cells. The eosinophil's immune suppressive functions were mediated by eosinophil-derived molecules, such as eosinophil peroxidase (EPX) and major basic protein (MBP). The expression of Ras-like protein in the brain 27a (Rab27a) was detected in eosinophils, which controlled the release of MBP and EPX by eosinophils. Eosinophil mediators had two contrast effects on inducing inflammatory responses or rendering immune suppressive effects, depending on the released amounts. Administration of an inhibitor of Rab27a at proper dosage could alleviate experimental airway allergy. To sum up, eosinophils have immune suppressive functions and are also inflammation inducers. Rab27a governs the release of EPX and MBP from eosinophils, which leads to immune suppression or inflammation. Modulation of Rab27a can alleviate airway allergy responses by modulating eosinophil's immune suppressive functions, which has the translational potential for the management of eosinophil-related diseases.

An association between elevated telomerase reverse transcriptase expression and the immune tolerance disruption of dendritic cells.

BACKGROUND: To elucidate the mechanism of dysfunction of tolerogenic dendritic cells (DCs) is of significance. Telomerase involves the regulation of the cell fate and activities. The objective of this study is to investigate the role of telomerase reverse transcriptase (TERT) in regulating the tolerogenic feature of DCs. METHODS: The telomerase was assessed in DCs, which were collected from patients with allergic rhinitis (AR), healthy control (HC) subjects, and mice. RNAs were extracted from DCs, and analyzed by RNA sequencing (RNAseq), real-time quantitative RT-PCR, and Western blotting. RESULTS: The results showed that expression of TERT was higher in peripheral DCs of AR patients. The expression of IL10 in DCs was negatively correlated with the levels of TERT expression. Importantly, the levels of TERT mRNA in DCs were associated with the AR response in patients with AR. Endoplasmic reticulum (ER) stress promoted the expression of Tert in DCs. Sensitization with the ovalbumin-aluminum hydroxide protocol increased the expression of Tert in DCs by exacerbating ER stress. TERT interacting with c-Maf (the transcription factor of IL-10) inducing protein (CMIP) in DCs resulted in CMIP ubiquitination and degradation, and thus, suppressed the production of IL-10. Inhibition of Tert in DCs mitigated experimental AR. CONCLUSIONS: Elevated amounts of TERT were detected in DCs of patients with AR. The tolerogenic feature of DCs was impacted by TERT. Inhibited TERT attenuated experimental AR.

TRIM41 contributes to the pathogenesis of airway allergy by compromising dendritic cells' tolerogenic properties.

Dendritic cells (DC) play a crucial role in the initiation of immune responses. TRIM41, an E3 ubiquitin ligase, can facilitate targeting protein degradation. The purpose of this study is to analyze the role of TRIM41 in the pathogenesis of airway allergy (AA) and the impact of regulating TRIM41 on suppressing AA. We observed that the airway DCs of AA mice had a higher expression of Trim41. The expression of Trim41 in airway DCs was associated with the DCs' tolerogenic functions of AA mice. The AA responses, including increased amounts of eosinophil peroxidase, mast cell protease-1, Th2 cytokines, and specific IgE in bronchoalveolar lavage fluids, were positively correlated with the Trim41 expression in mouse airway DCs. TRIM41 induced c-Maf degradation and interfered with the Il10 expression in airway DCs, which could be counteracted by inhibiting TRIM41. Regulation of TRIM41 mitigated experimental AA responses.

Nasal mucosal fibroblasts produce IL-4 to induce Th2 response.

Th2 polarization is essential for the pathogenesis of allergic rhinitis (AR). Th2 polarization's mechanism requires further understanding. IL-4 is the primary cytokine involved in Th2 response. Fibroblasts play a role in immune regulation. This study aims to elucidate the role of nasal mucosal fibroblast-derived IL-4 in the induction of Th2 responses. Nasal mucosal tissues were obtained from surgically removed samples from patients with nasal polyps, whether with or without AR. Fibroblasts were isolated from the tissues by flow cytometry cell sorting, and analyzed by RNA sequencing (RNAseq). The data from RNAseq showed that nasal fibroblasts expressed genes of GATA3, CD80, CD83, CD86, STAT6, IL2, IL4, IL5, IL6, IL13 and costimulatory factor. The data were verified by RT-qPCR. The level of gene activity was positively correlated with those of AR-related cytokines present in nasal secretions. Nasal fibroblasts release IL-4 upon activation. Nasal fibroblasts had the ability to transform naive CD4+ T cells into Th2 cells, which can be eliminated by inhibiting IL-4 receptor or CD28 in CD4+ T cells. To sum up, nasal mucosal fibroblasts produce IL-4, which can induce Th2 cell development. The data implicate that nasal fibroblasts are involved in the pathogenesis of nasal allergy.

Direct exposure to CpG and specific antigens mitigate airway allergy through modulating dendritic cell properties.

BACKGROUND: CpG oligodeoxynucleotide (CpG-ODN; CpG, in short) has been employed as an adjuvant in allergen specific immunotherapy (AIT) to treat allergic diseases. The underlying mechanism needs to be further explained. The aim of this study is to examine the mechanism by which CpG and dust mite extracts (DME, a specific antigen) alleviate experimental airway allergy. METHODS: DME was used as the specific allergen to establish an airway allergy mouse model. The mice were directly exposed to DME and CpG through nasal instillations (the CpG.DME therapy). The response of DCs and allergic responses in the airways were assessed using immunological approaches. RESULTS: The airway allergy reaction was effectively suppressed by CpG.DME therapy. The administration of CpG or DME alone did not have any significant suppressive effects on the airway allergic response. Direct exposure to CpG.DME induced type 1 DCs (DC1s) and plasmacytoid DCs (pDCs), while CpG alone induced DC1s and DME alone induced DC2s in the airway tissues. Both DC1s and pDCs were required for the induction of type 1 regulatory T cells in the airway tissues by CpG.DME therapy. Depletion of either pDCs or DC1s abolished the induction of Tr1 cells, and abolished the suppressive effects on airway allergic response by the CpG.DME therapy. CONCLUSIONS: Direct exposure to CpG.DME induces DC1s and pDCs in the airway tissues. DC1s in synergy with pDCs induce type 1 regulatory T cells. The CpG.DME therapy is effective in suppressing allergic responses in mice with airway allergy.

Subconjunctival injection of rapamycin-loaded polymeric microparticles for effective suppression of noninfectious uveitis in rats.

Noninfective uveitis is a major cause of vision impairment, and corticosteroid medication is a mainstay clinical strategy that causes severe side effects. Rapamycin (RAPA), a potent immunomodulator, is a promising treatment for noninfective uveitis. However, because high and frequent dosages are required, it is a great challenge to implement its clinical translation for noninfective uveitis therapy owing to its serious toxicity. In the present study, we engineered an injectable microparticulate drug delivery system based on biodegradable block polymers (i.e., polycaprolactone-poly (ethylene glycol)-polycaprolactone, PCEC) for efficient ocular delivery of RAPA via a subconjunctival injection route and investigated its therapeutic efficacy in an experimental autoimmune uveitis (EAU) rat model. RAPA-PCEC microparticles were fabricated using the emulsion-evaporation method and thoroughly characterized using scanning electron microscopy, fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. The formed microparticles exhibited slow in vitro degradation over 28 days, and provided both in vitro and in vivo sustained release of RAPA over 4 weeks. Additionally, a single subconjunctival injection of PCEC microparticles resulted in high ocular tolerance. More importantly, subconjunctival injection of RAPA-PCEC microparticles significantly attenuated the clinical signs of EAU in a dose-dependent manner by reducing inflammatory cell infiltration (i.e., CD45+ cells and Th17 cells) and inhibiting microglial activation. Overall, this injectable microparticulate system may be promising vehicle for intraocular delivery of RAPA for the treatment of noninfective uveitis.

Inhibition of DNMT1 attenuates experimental food allergy.

BACKGROUND: The treatment of food allergy (FA) needs improvement. The treatment of immune disorders can be improved by regulating epigenetic marks, which is a promising method. The objective of this research is to alleviate experimental FA by employing an inhibitor of DNA methyltransferase-1 (DNMT1). METHODS: Ovalbumin was used as the specific antigen to establish a mouse model of FA. Intestinal IL-35+ regulatory B cells (Breg cells) were isolated from FA mice, and characterized using immunological approaches. RESULTS: FA mice had a lower frequency of IL-35+ Breg cells, which was inversely correlated with their FA response. The quantity of IL-35 was lower in intestinal Breg cells from FA mice. Hypermethylation status was detected in the Il35 promoter, which was accompanied with high levels of H3K9me3. Enforced expression of DNMT1 hindered the promoter activity of the IL35 gene. Administration of an inhibitor of DNMT1 (RG108) restored the immune regulatory capacity of FA intestinal Bregs, and effectively suppressed the expression of DNMT1, and attenuated experimental FA. CONCLUSIONS: The elevated quantity of DNMT1 in intestinal Breg cells compromises the expression of IL-35 and affects the immune regulatory functions, which facilitates the development of FA. The immune regulatory functions of intestinal Breg cells are restored and experimental FA is attenuated by inhibiting DNMT1.

Regulation of Tert methylation alleviates food allergy via regulating the Tert-IL10 signal pathway.

BACKGROUND: The cause of food allergy (FA) is still a mystery. Telomerases are involved in the regulation of immune responses. This study aims to gain an understanding of the contribution of telomerase reverse transcriptase (TERT) to the pathogenesis of FA. METHODS: A murine FA model was established with ovalbumin as the specific antigen. The role of TERT in regulating dendritic cell (DC) immune tolerogenic functions was evaluated in this murine model. RESULTS: We observed that the Tert promoter was at demethylation status and the Tert expression was elevated in DCs of FA mice. The Tert expression in DCs had a positive correlation with the FA response. TERT prevented the induction of Il10 expression in DCs. The immune tolerogenic functions of DCs were diminished by TERT. The immune tolerogenic functions of DC were restored by CpG by boosting the Tert promoter methylation. Administration of CpG promoted the therapeutic effects of allergen specific immunotherapy in FA mice. CONCLUSIONS: Low levels of Il10 expression and high levels of Tert expression were observed in intestinal DCs of FA mice. CpG exposure restored the expression of Il10 and increased the therapeutic benefits of allergen-specific immunotherapy.

Undersized telomeres in regulatory T cells link to the pathogenesis of allergic rhinitis.

Telomeres are an important biomarker in the cell destiny. The relationship between telomeres and regulatory T cells (Tregs) has not yet been investigated. The objective of this study is to evaluate the link between Tregs' telomere length and allergic rhinitis (AR)'s pathogenesis. Here, we report that low telomerase activity and high endoplasmic reticulum stress status were observed in Tregs from AR patients, as shown in the results. Immune regulatory molecules levels were correlated with the length of Tregs' telomeres. The immune-suppressive functions of Tregs were associated with the telomere length/Telomerase reverse transcriptase/Telomerase protein component 1 status in Tregs. The levels of telomere length/telomerase in airway Tregs were reduced by sensitization. Endoplasmic reticulum stress signaling pathway of proline-rich receptor-like protein kinase-eukaryotic translation initiation factor 2A (eIF2a) was associated with the regulation of telomerase. Inhibiting eIF2a had an effect on upregulating telomerase activity in Tregs and mitigating experimental AR.

Endoplasmic reticulum stress drives macrophages to produce IL-33 to favor Th2 polarization in the airways.

Interleukin (IL)-33 is a key driver of T helper 2 (Th2) cell polarization. Endoplasmic reticulum (ER) stress plays a role in the skewed T cell activation. The objective of this project is to elucidate the role of IL-33 derived from macrophages in inducing Th2 polarization in the airways. In this study, bronchoalveolar lavage fluids (BALF) were collected from patients with asthma and healthy control subjects. Macrophages were isolated from the BALF by flow cytometry cell sorting. An asthmatic mouse model was established using the ovalbumin/alum protocol. The results showed that increased IL33 gene activity and ER stress-related molecules in BALF-derived M2a macrophages was observed in asthmatic patients. Levels of IL33 gene activity in M2a cells were positively correlated with levels of asthma response in asthma patients. Sensitization exacerbated the ER stress in the airway macrophages, which increased the expression of IL-33 in macrophages of airway in sensitized mice. Conditional ablation of Il33 or Perk or Atf4 genes in macrophages prevented induction of airway allergy in mice. In conclusion, asthma airway macrophages express high levels of IL-33 and at high ER stress status. Inhibition of IL-33 or ER stress in macrophages can effectively alleviate experimental asthma.

Multifunctional nanogel loaded with cerium oxide nanozyme and CX3CL1 protein: Targeted immunomodulation and retinal protection in uveitis rat model.

Effectively addressing retinal issues represents a pivotal aspect of blindness-related diseases. Novel approaches involving reducing inflammation and rebalancing the immune response are paramount in the treatment of these conditions. This study delves into the potential of a nanogel system comprising polyethylenimine-benzene boric acid-hyaluronic acid (PEI-PBA-HA). We have evaluated the collaborative impact of cerium oxide nanozyme and chemokine CX3CL1 protein for targeted immunomodulation and retinal protection in uveitis models. Our nanogel system specifically targets the posterior segment of the eyes. The synergistic effect in this area reduces oxidative stress and hampers the activation of microglia, thereby alleviating the pathological immune microenvironment. This multifaceted drug delivery system disrupts the cycle of oxidative stress, inflammation, and immune response, suppressing initial immune cells and limiting local retinal structural damage induced by excessive immune reactions. Our research sheds light on interactions within retinal target cells, providing a promising avenue for the development of efficient and innovative drug delivery platforms.