Apolipoprotein A-I inhibited group II innate lymphoid cell response mediated by microRNA-155 in allergic rhinitis

Background

Group 2 innate lymphoid cells (ILC2s) have been found to take part in type 2 inflammation by secreting TH2 cytokines. Apolipoprotein A-I (Apo-AI), a major structural and functional protein of high-density lipoproteins, has anti-inflammatory effects on neutrophils, monocytes, macrophages, and eosinophils. However, its effects on ILC2s are not well characterized.

Objective

We aimed to investigate the effect of Apo-AI on the proliferation and function of ILC2s as well as its possible mechanism.

Methods

The protein expression of Apo-AI and the percentage of ILC2s in peripheral blood between 20 allergic rhinitis patients and 20 controls were detected by ELISA and flow cytometry. The effect of Apo-AI and miR-155 on ILC2 proliferation and function was detected by tritiated thymidine incorporation and ELISA. Anima models were adopted to verify the effect of Apo-AI in vivo.

Results

Elevated expression of Apo-AI was observed in allergic rhinitis patients. Apo-AI promotes ABCA1 expression by ILC2s, which can be inhibited by anti-Apo-AI. Apo-AI decreased ILC2 proliferation and the microRNA levels of GATA3 and RORα from ILC2s. The miR-155 overexpression promoted the upregulation of GATA3 and type II cytokines from ILC2s, while the addition of Apo-AI or miR-155 inhibitor significantly inhibited expression of GATA3 and type II cytokines by ILC2s. Apo-AI-/- mice showed as enhanced allergen-induced airway inflammation. The miR-155 inhibitor can reverse the enhanced allergen-induced airway inflammation in Apo-AI-/- mice, while miR-155 mimics can reverse the decreased allergen-induced airway inflammation in Apo-AI-treated mice.

Conclusion

Apo-AI suppressed the proliferation and function of ILC2s through miR-155 in allergic rhinitis. Our data provide new insights into the mechanism of allergen-induced airway inflammation.

The Role of Regulatory T Cells in Allergic Diseases: Collegium Internationale Allergologicum (CIA) Update 2024

BACKGROUND

Allergy represents a major health problem of increasing prevalence worldwide with a high socioeconomic impact. Our knowledge on the molecular mechanisms underlying allergic diseases and their treatments has significantly improved over the last years. The generation of allergen-specific regulatory T cells (Tregs) is crucial in the induction of healthy immune responses to allergens, preventing the development and worsening of allergic diseases.

SUMMARY

In the last decades, intensive research has focused on the study of the molecular mechanisms involved in Treg development and Treg-mediated suppression. These mechanisms are essential for the induction of sustained tolerance by allergen-specific immunotherapy (AIT) after treatment discontinuation. Compelling experimental evidence demonstrated altered suppressive capacity of Tregs in patients suffering from allergic rhinitis, allergic asthma, food allergy, or atopic dermatitis, as well as the restoration of their numbers and functionality after successful AIT.

KEY MESSAGE

The better understanding of the molecular mechanisms involved in Treg generation during allergen tolerance induction might well contribute to the development of novel strategies for the prevention and treatment of allergic diseases.

Regulatory T cells in dominant immunologic tolerance

Regulatory T cells expressing the transcription factor forkhead box protein 3 mediate peripheral immune tolerance both to self-antigens and to the commensal flora. Their defective function due to inborn errors of immunity or acquired insults is associated with a broad range of autoimmune and immune dysregulatory diseases. Although their function in suppressing autoimmunity and enforcing commensalism is established, a broader role for regulatory T cells in tissue repair and metabolic regulation has emerged, enabled by unique programs of tissue adaptability and specialization. In this review, we focus on the myriad roles played by regulatory T cells in immunologic tolerance and host homeostasis and the potential to harness these cells in novel therapeutic approaches to human diseases.

Allergen-induced CD11c + dendritic cell pyroptosis aggravates allergic rhinitis

BACKGROUND

Pyroptosis is crucial for controlling various immune cells. However, the role of allergen-induced CD11c + dendritic cell (DC) pyroptosis in allergic rhinitis (AR) remains unclear.

METHODS

Mice were grouped into the control group, AR group and necrosulfonamide-treated AR group (AR + NSA group). The allergic symptom scores, OVA-sIgE titres, serum IL-1β/IL-18 levels, histopathological characteristics and T-helper cell-related cytokines were evaluated. CD11c/GSDMD-N-positive cells were examined by immunofluorescence analysis. Murine CD11c + bone marrow-derived DCs (BMDCs) were induced in vitro, stimulated with OVA/HDM, treated with necrosulfonamide (NSA), and further cocultured with lymphocytes to assess BMDC function. An adoptive transfer murine model was used to study the role of BMDC pyroptosis in allergic rhinitis.

RESULTS

Inhibiting GSDMD-N-mediated pyroptosis markedly protected against Th1/Th2/Th17 imbalance and alleviated inflammatory responses in the AR model. GSDMD-N was mainly coexpressed with CD11c (a DC marker) in AR mice. In vitro, OVA/HDM stimulation increased pyroptotic morphological abnormalities and increased the expression of pyroptosis-related proteins in a dose-dependent manner; moreover, inhibiting pyroptosis significantly decreased pyroptotic morphology and NLRP3, C-Caspase1 and GSDMD-N expression. In addition, OVA-induced BMDC pyroptosis affected CD4 + T-cell differentiation and related cytokine levels, leading to Th1/Th2/Th17 cell imbalance. However, the Th1/Th2/Th17 cell immune imbalance was significantly reversed by NSA. Adoptive transfer of OVA-loaded BMDCs promoted allergic inflammation, while the administration of NSA to OVA-loaded BMDCs significantly reduced AR inflammation.

CONCLUSION

Allergen-induced dendritic cell pyroptosis promotes the development of allergic rhinitis through GSDMD-N-mediated pyroptosis, which provides a clue to allergic disease interventions. Video Abstract.

Calpeptin may reverse glucocorticoid-resistance of allergic rhinitis associated with cigarette smoke exposure by down-regulating interferon regulatory factor 1

Cigarette smoke exposure is an important factor in chronic inflammation in patients with allergic rhinitis (AR); however, the relationship between cigarette smoke and AR-related glucocorticoid resistance requires further study. In mice, calpeptin significantly reduces inflammation of the lower respiratory tract caused by cigarette smoke, but whether it can treat glucocorticoid-resistant AR caused by cigarette smoke requires further research. In this study, we confirmed that cigarette smoke exposure can aggravate the Th2 inflammatory response in AR leading to glucocorticoid resistance. The underlying mechanism may be related to decreased expression of DNA methyltransferase 3a (Dnmt3a), and increased expression of interferon regulatory factor 1 (IRF1). In addition, we found that calpeptin can inhibit the expression of IRF1 and thus treat AR-associated glucocorticoid resistance in rats exposed to cigarette smoke. These data suggest that calpeptin may downregulate IRF1 and therefore treat glucocorticoid resistance in AR-associated with cigarette smoke exposure.

Mycotoxins Have a Potential of Inducing Cell Senescence: A New Understanding of Mycotoxin Immunotoxicity

Mycotoxins result in immune dysfunction and cause immune diseases in animals and humans. However, the mechanisms of immunotoxicity involved in mycotoxins have not been fully explored, and emerging evidence suggests that these toxins may promote their immunotoxicity via cellular senescence. Mycotoxins induce cell senescence after DNA damage, and activate signaling via the NF-κB and JNK pathways to promote the secretion of senescence-associated secretory phenotype (SASP) cytokines including IL-6, IL-8, and TNF-α. DNA damage can also over-activate or cleave poly (ADP-ribose) polymerase-1 (PARP-1), increase the expression of cell cycle inhibitory proteins p21, and p53, and induce cell cycle arrest and then senescence. These senescent cells further down-regulate proliferation-related genes and overexpress inflammatory factors resulting in chronic inflammation and eventual immune exhaustion. Here we review the underlying mechanisms by which mycotoxins trigger cell senescence and the potential roles of SASP and PARP in these pathways. This work will help to further understand the mechanisms of immunotoxicity involved in mycotoxins.

Resveratrol inhibits AhR/Notch axis and reverses Th17/Treg imbalance in purpura by activating Foxp3

Background

Resveratrol has been reported to reverse the imbalance of T helper 17/regulatory T (Th17/Treg) by inhibiting the aryl hydrocarbon receptor pathway to treat immune thrombocytopenia. However, the regulation mechanism of the Notch signaling pathway by resveratrol has not been reported in purpura. This study is aimed to explore the mechanism of resveratrol ultrafine nanoemulsion (Res-mNE) in immune thrombocytopenia.

Methods

The immune thrombocytopenia mouse model was constructed to explore the effect of RES-mNE on immune thrombocytopenia. Cluster of differentiation 4 (CD4+) T cells were isolated and treated with different medications. CD4+ T cells were induced to differentiate into Th17 cells and Treg cells. Flow cytometry was used to detect the proportion of Th17 cells and Treg cells. The secretion was measured by the enzyme-linked immunosorbent assay (ELISA). Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blot were used to detect the mRNA and protein levels.

Results

Th17 cells, IL-17A and IL-22 increased in the immune thrombocytopenia mouse model, and the Treg cells and IL-10 decreased. Res-mNE promoted Treg cell differentiation and IL-10 secretion in CD4+ T cells while inhibiting Th17 cell differentiation and IL-17A and IL-22 levels. The AhR activator 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) reversed the effect of Res-mNE. Notch inhibitors reduced the ratio of Th17/Treg differentiation. Res-mNE activated the expression of Foxp3 by mediating AhR/Notch signaling to reverse the imbalance of Th17/Treg differentiation in immune thrombocytopenia.

Conclusion

Taken together, our findings demonstrated that RES-mNE inhibited the AhR/Notch axis and reversed Th17/Treg imbalance by activating Foxp3.

Upregulated expression of Notch1/4 - JAG-1/DLL-1 detected in allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is a chronic disease with high prevalence. There are currently many treatments available. However, despite an often good therapeutic response, many patients still report impairment in quality of life (QoL) during the pollen season. A skewed T helper (Th)2 polarization is a well-acknowledged pathologic feature of AR. In animal models, local notch signaling in peripheral tissue seems crucial for Th2 cell differentiation and the development of AR. However, the involvement of Notch signaling in Th2 cell differentiation and the development of AR in humans remains unknown. Hence, the present study investigated the human expression of Notch receptors on CD4⁺ T-cells in nasal mucosa and blood. Correspondingly Notch ligand expression was assessed on nasal epithelial cells and neutrophils.

METHODOLOGY

Nasal brush and blood samples from 18 patients with pollen-induced AR and 22 healthy controls were collected outside the pollen season. Notch 1-4 and Jagged-1,2 and Delta-like ligand 1,3-4 was analyzed using flow cytometry.

RESULTS

The fraction of CD4⁺Notch1⁺ and CD4⁺Notch4⁺ T-cells was higher in AR patients than in healthy control patients. Further, the expression levels of the Notch ligands JAG-1 and DLL-1 were increased in nasal epithelial cells from AR patients compared to healthy control patients. In addition, AR patients displayed higher expression of JAG-1 on neutrophils both in the nasal mucosa and in peripheral blood.

CONCLUSION

The present study is the first to demonstrate increased activity in the Notch1/4 - JAG-1/DLL-1 pathways among allergic individuals. Further propagating the importance of Notch signalling in AR and blocking JAG-1 and DLL-1-induced Notch signalling by nasal epithelial cells and Neutrophils are potential targets to reduce allergic airway inflammation.

Pathogenesis of allergic diseases and implications for therapeutic interventions

Allergic diseases such as allergic rhinitis (AR), allergic asthma (AAS), atopic dermatitis (AD), food allergy (FA), and eczema are systemic diseases caused by an impaired immune system. Accompanied by high recurrence rates, the steadily rising incidence rates of these diseases are attracting increasing attention. The pathogenesis of allergic diseases is complex and involves many factors, including maternal-fetal environment, living environment, genetics, epigenetics, and the body's immune status. The pathogenesis of allergic diseases exhibits a marked heterogeneity, with phenotype and endotype defining visible features and associated molecular mechanisms, respectively. With the rapid development of immunology, molecular biology, and biotechnology, many new biological drugs have been designed for the treatment of allergic diseases, including anti-immunoglobulin E (IgE), anti-interleukin (IL)-5, and anti-thymic stromal lymphopoietin (TSLP)/IL-4, to control symptoms. For doctors and scientists, it is becoming more and more important to understand the influencing factors, pathogenesis, and treatment progress of allergic diseases. This review aimed to assess the epidemiology, pathogenesis, and therapeutic interventions of allergic diseases, including AR, AAS, AD, and FA. We hope to help doctors and scientists understand allergic diseases systematically.

Blocking Notch signalling reverses miR-155-mediated inflammation in allergic rhinitis

Although recent studies have shown that the Notch signalling pathway induces the production of Th2-related immune factors, the exact mechanism through which Notch signalling exacerbates allergic rhinitis (AR) remains unknown. To investigate the roles of Notch in AR, serum, nasal mucosa and spleen samples were isolated from BALB/c mice. Paraffin sections were stained with haematoxylin and eosin (H&E) or periodic acid-Schiff (PAS) to assess inflammation. Flow cytometry was performed to detect group 2 innate lymphoid cells (ILC2s) in the serum samples, and cytokine levels were measured by enzyme-linked immunosorbent assays (ELISAs). The mRNA expression levels of the Notch signalling pathway components and miR-155 were measured by quantitative real-time PCR (qRT-PCR). In addition, human nasal epithelial cells (HNEpCs) were cultured to investigate the functional consequences of Notch pathway inhibition. The findings demonstrated that symptomatology and pathology were substantially altered, and AR model mice were established. In vivo stimulation with ovalbumin (OVA) significantly increased the Th2-type immune responses and the expression of OVA-sIgE, IL-4, GATA3, NF-κB and miR-155. However, the Notch signalling pathway was significantly deteriorated in AR, and this effect was accompanied by reduced Notch1, Notch2, RBPj and Hes1 levels. These effects were abrogated by gamma-secretase inhibitor IX (DAPT) treatment, and DAPT inhibited the wound healing and proliferation of HNEpCs in a dose-dependent manner. Therefore, our results suggest that blocking the Notch pathway may alleviate miR-155-mediated inflammation via the regulation of immune homeostasis in AR.

The Notch Signaling Pathway Contributes to Angiogenesis and Tumor Immunity in Breast Cancer

Breast cancer in women is the first leading tumor in terms of incidence worldwide. Some subtypes of BC lack distinct molecular targets and exhibit therapeutic resistance; these patients have a poor prognosis. Thus, the search for new molecular targets is an ongoing challenge for BC therapy. The Notch signaling pathway is found in both vertebrates and invertebrates, and it is a highly conserved in the evolution of the species, controlling cellular fates such as death, proliferation, and differentiation. Numerous studies have shown that improper activation of Notch signaling may lead to excessive cell proliferation and cancer, with tumor-promoting and tumor-suppressive effects in various carcinomas. Thus, inhibitors of Notch signaling are actively being investigated for the treatment of various tumors. The role of Notch signaling in BC has been widely studied in recent years. There is a growing body of evidence suggesting that Notch signaling has a pro-oncogenic role in BC, and the tumor-promoting effect is largely a result of the diverse nature of tumor immunity. Immunological abnormality is also a factor involved in the pathogenesis of BC, suggesting that Notch signaling could be a target for BC immunotherapies. Furthermore, angiogenesis is essential for BC growth and metastasis, and the Notch signaling pathway has been implicated in angiogenesis, so studying the role of Notch signaling in BC angiogenesis will provide new prospects for the treatment of BC. We summarize the potential roles of the current Notch signaling pathway and its inhibitors in BC angiogenesis and the immune response in this review and describe the pharmacological targets of Notch signaling in BC, which may serve as a theoretical foundation for future research into exploring this pathway for novel BC therapies.

Allergen immunotherapy enhances the immunosuppressive effects of Treg cells to alleviate allergic rhinitis by decreasing PU-1+ Treg cell numbers

OBJECTIVE

To investigate the role of Tregs and their subtypes in the treatment of allergic rhinitis with allergen immunotherapy (AIT) as well as the underlying mechanism.

METHODS

1. Thirty-one healthy controls, 29 Allergic rhinitis (AR) patients and 16 AR patients treated with AIT were recruited. The total nasal symptom scores (TNSSs) were calculated. The serum levels of IgE, IL-2, TNF-α, IFN-γ, IL-4, IL-5, IL-6, IL-10 and IL-17 were measured. 2. Changes in the proportions of CD4+ T cells, Treg cells, Treg subtypes and Th1/Th2/Th9/Th17/Tfh cells in the peripheral blood of the subjects in the three groups were measured. 3. The correlations of Treg cells, Treg subtypes and TNSS with the levels of various cytokines in the AR group and AIT group were analysed.

RESULTS

1. Compared with the control group, the TNSS and IgE, IL-5 and IL-6 levels in the AR group were significantly increased, while the IL-2, IFN-γ and IL-10 levels were significantly decreased (P < 0.05). Compared with the AR group, the TNSS and IgE, IL-5 and IL-6 levels in the AIT group were significantly decreased, while the IL-2, IFN-γ and IL-10 levels were significantly increased (P < 0.05). 2. Compared with the control group, the proportions of Tregs, GATA3+ Tregs and Th1 cells in the AR group were significantly reduced, while the proportions of PU-1+ Tregs, T-bet+ Tregs and Th2 cells were significantly increased (P < 0.05). Compared with the AR group, the proportions of Tregs and Th1 cells in the AIT group were significantly increased, while the proportions of PU-1+ Tregs and Th2 cells were decreased (P < 0.05). 3. Correlation analysis showed that Treg cell proportions were negatively correlated with the TNSS, sIgE levels, IL-5 levels and IL-6 levels but positively correlated with the IL-2 and IL-10 levels (P < 0.05). PU-1+ Treg cell proportions were positively correlated with the TNSS, sIgE levels, IL-5 levels and IL-6 levels but negatively correlated with the Treg cell proportions, IL-2 levels and IL-10 levels (P < 0.05).

CONCLUSIONS

AIT can reduce the proportions of PU-1+ Treg subtypes in AR patients. PU-1+ Treg cell numbers can potentially be used as an indicator to monitor the therapeutic effect of AIT on AR.

The positive feedback loop of furin and TGFβ1 enhances the immune responses of Tregs to hepatocellular carcinoma cells and hepatitis B virus in vitro

Regulatory T cells (Tregs) can exert immunosuppressive activity. Furin can regulate Treg functions, hepatitis B virus (HBV) persistent infection, and hepatocellular carcinoma (HCC) development. However, it remains unknown whether furin can regulate the immune responses of Tregs to HBV and HCC cells. Here, coculture systems of HBV1.3P-HepG2.3P-HepG2 cells and Tregs transduced with or without lentiviral particles that could overexpress furin or knockdown furin/transforming growth factor β1 (TGFβ1) were established to investigate the regulatory relationship between furin and TGFβ1 and the effect of furin/TGFβ1 on Treg activity. Also, the effects of furin overexpression or furin/TGFβ1 knockdown in Tregs on the immunological activity of effector T cells (Teffs)/cytotoxic T lymphocytes (CTLs) and HBV replication/expression were explored in the coculture system of Teff/CTL, Treg, and HBV1.3P-HepG2 cells. Our results showed that furin expression and TGFβ1 secretion were notably increased in Tregs, and Furin and TGFβ1 formed a positive feedback loop to activate Tregs in the coculture system of Tregs and HBV1.3P-HepG2 cells. Furin or TGFβ1 knockdown in Tregs promoted Teff cell proliferation, stimulated interleukin-2 and interferon-γ secretion, and inhibited HBV replication/gene expression in the coculture system of Teff, Treg, and HBV1.3P-HepG2 cells. Moreover, furin or TGFβ1 depletion in Tregs enhanced the killing activity of CTLs against HBV1.3P-HepG2 cells and curbed HBV replication/gene expression in the coculture system of Tregs, CTLs, and HBV1.3P-HepG2 cells. In conclusion, the positive feedback loop of furin and TGFβ1 enhanced the immune responses of Tregs to HCC cells and HBV in vitro.

Lycopene Alleviates Chronic Stress-Induced Spleen Apoptosis and Immunosuppression via Inhibiting the Notch Signaling Pathway in Rats

Chronic stress induction in immunosuppression and splenocyte apoptosis is commonly associated with increased susceptibility to various diseases. Lycopene (LYC) is a member of the carotenoid family with immune restoration and anti-apoptotic function. However, little is known about the mechanisms underlying the protective roles of LYC against spleen injury induced by chronic stress. Herein, male Wistar rats were undergoing chronic restraint stress and/or administered LYC (10 mg/kg) for 21 days. The effective model establishment was validated by open-field tests and levels of corticosterone in serum. Histopathological staining observation displayed that LYC could reduce chronic stress-induced spleen structure damage. Furthermore, LYC treatment significantly reduced the number of apoptotic-positive splenocytes caused by chronic stress via the death receptor apoptotic pathway. We detected the interleukin 4 and interferon γ levels in serum and spleen to determine the ratio of Th1 and Th2 and found that LYC can alleviate the immunosuppression induced by chronic stress. Notably, western blot and real-time polymerase chain reaction indicated that LYC can reduce the expression of the Notch-pathway-related proteins and mRNA in rats exposed to chronic stress. Further study of the potential mechanisms by adding the Notch pathway inhibitor DAPT revealed that LYC alleviates the structure damage, apoptosis, and immunosuppression caused by chronic stress via the suppression of the Notch pathway. Overall, this study presents a strong rationale to target LYC as a treatment strategy to relieve chronic stress-induced spleen injury.

Notch2 suppresses the development of allergic rhinitis by promoting FOXP3 expression and Treg cell differentiation

AIMS

Notch signaling is closely related to a variety of diseases, but the role of Notch2 in allergic rhinitis (AR) remain unclear. This study was performed to investigate the effects of Notch2 on the differentiation of Treg cells and on the inflammatory response of AR.

MATERIALS AND METHODS

Peripheral blood (including 101 AR patients and 66 Controls) and nasal mucosa (including 19 AR patients and 17 Controls) were collected to detect the expression levels of Notch2, NICD2 and FOXP3. CD4+ T cells of human origin were selected to detect the effects of Notch2 on the differentiation of Treg cells and FOXP3. An AR mouse model was established, and lentiviruses overexpressing Notch2 were administered. Then, allergic symptoms, OVA-sIgE titers, nasal mucosal inflammation, Th1/Th2/Th17 cytokines and splenic Treg cells were assessed.

KEY FINDINGS

Compared with that in the Control group, the expression of Notch2 in the AR group was decreased, and Notch2 expression was negatively correlated with the degree of allergy (P < 0.01). The expression levels of Notch2, NICD2 and FOXP3 were decreased in the nasal mucosa of AR patients. Notch2 can promote the differentiation of human Treg cells in vitro (P < 0.05), and Notch2 can directly promote FOXP3 transcription. Animal experiments showed after the upregulation of Notch2 expression, the allergic inflammatory of mice with AR was reduced, the differentiation of Treg cells was increased, and the imbalance of T cells was reversed (P < 0.05).

SIGNIFICANCE

Notch2 promotes the differentiation of Treg cells by upregulating FOXP3 expression, thus significantly inhibiting the inflammatory response of AR.

Decreasing lncRNA PVT1 causes Treg/Th17 imbalance via NOTCH signaling in immune thrombocytopenia

Objectives: Immune thrombocytopenia (ITP) is an autoimmune disease. T helper cell 17 (Th17) cells are increased in peripheral blood of ITP patients. NOTCH signaling is involved in Th17 cell differentiation and function. Besides, lncRNA Plasmacytoma variant translocation 1 (PVT1) was decreased in experimental autoimmune encephalomyelitis, and overexpressing PVT1 inhibited Th17 cell differentiation. Here, we aimed to investigate the effect of lncRNA PVT1 on ITP and its related mechanism.Methods: The number of Th17 cells and Treg cells was carried out using flow cytometry. PVT1 levels were detected by quantitative real-time PCR. Interleukin-17 (IL-17) levels and transforming growth factor-β (TGF-β) levels were detected by enzyme-linked immunosorbent assay. Protein levels of retinoid acid-related orphan receptor γ t (RORγt), forkhead box P3 (Foxp3), and NOTCH1 were carried out by western blot. NOTCH1 ubiquitylation was detected by ubiquitination assay.Results: PVT1 was down-regulated and Th17 cells were up-regulated in ITP patients. Overexpression of PVT1 decreased the number of Th17 cells, and also decreased the levels of IL-17, RORγt, and NOTCH1. Besides, PVT1 could bind to NOTCH1 and mediated NOTCH1 degradation by increasing its ubiquitination. Additionally, excessive expression of PVT1 could increase the levels of PVT1, reduce the amount of Th17 cells, as well as the levels of IL-17, RORγt, and NOTCH1, while co-overexpressing NOTCH1 reversed the results.Conclusion: PVT1 was down-regulated in ITP patients. Overexpressing PVT1 might reduce Th17 cell differentiation by down-regulating NOTCH1, and further alleviated the development of ITP.

Role of the Notch ligands Jagged1 and Delta4 in Th17/Treg immune imbalance in a mouse model of chronic asthma

PURPOSE

Asthma is associated with a T helper (Th)17/regulatory T (Treg) cells immune imbalance where the Notch signaling pathway contributes vitally. This study aimed to explore the role of Notch ligands Jagged1 and Delta4 in the Th17/Treg immune imbalance of chronic asthmatic mice.

METHODS

The experimental animals were randomly assigned to the Saline, ovalbumin (OVA), and OVA + γ-secretase inhibitor (GSI) groups. A mouse model of chronic asthma was induced by OVA sensitization and challenge. GSI was injected intraperitoneally before the OVA challenge in the OVA + GSI group. Lung function, lung histopathology and immunohistochemistry to assess airway inflammation, enzyme-linked immunosorbent assay to measure cytokines levels, flow cytometry to measure the proportions of Th17 (Th17%) and Treg% in CD4+T cells, quantitative real-time polymerase chain reaction and western blot to measure mRNA and protein levels of Jagged1 and Delta4 in lung tissue, and correlation analysis were performed.

RESULTS

Lung function and histopathology and IL-4, IL-13, and IFN-γ levels in the bronchoalveolar lavage fluid (BALF) of chronic asthmatic mice showed characteristic changes of asthma. The Th17%, Th17/Treg ratio, BALF and serum IL-17 levels, and IL-17/IL-10 ratio increased significantly in the OVA group, while the Treg% and IL-10 level significantly decreased. mRNA and protein expression levels of Jagged1 and Delta4 increased significantly. GSI could reduce the Th17%, Th17/Treg ratio, IL-17, IL-17/IL-10 ratio, and Jagged1 expression in chronic asthmatic mice. The mRNA and protein levels of Jagged1 and Delta4 were positively correlated with the Th17/Treg ratio in the OVA group, while only those of Jagged1 were positively correlated with the Th17/Treg ratio in the OVA + GSI group.

CONCLUSIONS

In chronic asthmatic mice, the Th17/Treg ratio increased, and the Notch ligands Jagged1 and Delta4 were overactive and positively regulated the Th17/Treg imbalance. GSI partially inhibited Jagged1 and relieved the Th17/Treg imbalance.

New concepts in pediatric rhinitis

Rhinitis-and especially allergic rhinitis (AR)-remains the most frequent hypersensitivity condition, affecting up to a quarter of the population and impacting the quality of life of individual patients and the health economy. Data, especially with respect to underlying pathophysiologic mechanisms, mainly derive from studies on adults and are subsequently extrapolated to the pediatric population. Therapeutic algorithms for children with rhinitis are long based on the same principles as in adults. We explore and describe novel aspects of rhinitis, ranging from mechanisms to disease classification, phenotypes, diagnostic and monitoring tools, and the use of treatments, with a focus on the traits of pediatric age groups.

Longdan Xiegan Decoction alleviates experimental autoimmune uveitis in rats by inhibiting Notch signaling pathway activation and Th17 cell differentiation

This study aimed to investigate the dynamic effects of the traditional Chinese medicine compound Longdan Xiegan Decoction (LXD) on the inhibition of Notch signaling pathway activation and T helper (Th) cell differentiation in rats with experimental autoimmune uveitis (EAU). Based on a network pharmacology strategy, we conducted protein interaction network analysis to construct an active ingredient-disease treatment network. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were further used to screen out the possible signaling pathways regulated by LXD in the treatment of uveitis. In the subsequent functional studies, we established an EAU rat model and investigated the regulatory role of LXD in the Notch signaling pathway and Th cell differentiation in rats with EAU. Female Lewis rats were randomly divided into a normal control (NC) group, an EAU group, and an LXD group. After the induction of EAU, the ocular inflammation and pathological changes in the rats in each group were observed; for documentation, a scanning laser ophthalmoscope (SLO) was used to observe fundus inflammation on day 12 after immunization. Additionally, quantitative polymerase chain reaction (Q-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression of Notch1, DLL4, IL-10 and IL-17A in the spleen, lymph nodes and ocular tissues of each group at 0, 6, 9, 12, 15 and 18 days after immunization. In addition, the dynamic frequencies of the CD4+, CD8+, Th17 and Treg cell subsets in the spleen, lymph nodes and ocular tissues were measured by flow cytometry. We found that the Notch signaling pathway was activated and the Th17 frequency was elevated in rats with EAU, leading to disrupted CD4+/CD8+ and Th17/Treg balance. The expression of Notch1, DLL4 and IL-17 mRNA and proteins in the EAU and LXD groups reached a peak on day 12, and then gradually decreased (all P < 0.05), and the ratios of the CD4+/CD8+ and Th17/Treg also peaked on day 12. However, after treatment with LXD, the expression of Notch1, DLL4 and IL-17 mRNA and proteins was significantly decreased (all P < 0.05), and the CD4+/CD8+ and Th17/Treg ratios significantly gradually returns to balance. LXD can efficiently inhibit Th17 cell differentiation, decrease inflammatory cytokine expression, and restore the CD4+/CD8+ and Th17/Treg balance by inhibiting the activation of the Notch signaling pathway in rats with EAU, thus effectively alleviating eye inflammation, protecting eye tissue structures, and positively regulating the immune state of the whole body and the intraocular microenvironment.

The correlation between the Th17/Treg cell balance and bone health

With the ageing of the world population, osteoporosis has become a problem affecting quality of life. According to the traditional view, the causes of osteoporosis mainly include endocrine disorders, metabolic disorders and mechanical factors. However, in recent years, the immune system and immune factors have been shown to play important roles in the occurrence and development of osteoporosis. Among these components, regulatory T (Treg) cells and T helper 17 (Th17) cells are crucial for maintaining bone homeostasis, especially osteoclast differentiation. Treg cells and Th17 cells originate from the same precursor cells, and their differentiation requires involvement of the TGF-β regulated signalling pathway. Treg cells and Th17 cells have opposite functions. Treg cells inhibit the differentiation of osteoclasts in vivo and in vitro, while Th17 cells promote the differentiation of osteoclasts. Therefore, understanding the balance between Treg cells and Th17 cells is anticipated to provide a new idea for the development of novel treatments for osteoporosis.

DAPT reverses the Th17/Treg imbalance in experimental autoimmune uveitis in vitro via inhibiting Notch signaling pathway

Uveitis is the most common cause in inflammatory eye diseases that can lead to visual impairment even blindness worldwide. T helper (Th) 17 and regulatory T (Treg) cells are critical mediators for immune response. Notch signaling can regulate the cell differentiation, playing a role in the pathogenesis of the diseases. In this study, we measured the expression levels of Notch1, DLL4, IL-10, IL-17, RORγt and Foxp3 in T cells from lymph node, spleen and eye tissues in experimental autoimmune uveitis (EAU) rats in vitro, determined the ratios of CD4⁺/CD8⁺ and Th17/Treg. Moreover, we also investigated the effect of Notch signaling inhibitor N-(N-(3,5-Difluorophenacetyl-L-alanyl))-S-phenylglycine t-Butyl Ester (DAPT) on Notch1, DLL4 expression and on Th17, Treg cell differentiation. The results indicated that the pathogenesis of uveitis accompanied by the elevated expression of Notch1, DLL4, IL-10, IL-17, RORγt, and Foxp3 as well as the imbalanced CD4⁺/CD8⁺ and Th17/Treg ratios. By contrast, inhibition of Notch signaling by DAPT can efficiently decrease Th17 cell response, downregulate the expression of Notch1, DLL4, IL-17 and the transcription of RORγt, reduce Th17 levels and restore the CD4⁺/CD8⁺, Th17/Treg balance. Moreover, DAPT can also inhibit Th17 cell differentiation in healthy rats, though the inhibitory capacity of Th17, Treg differentiation is less than that in EAU rats. Overall, Notch signaling activation can lead to the disturbed Th17/Treg balance in uveitis, whereas inhibition of Notch signaling can ameliorate the inflammatory response and may be a potential immunoregulatory strategy in patients with uveitis.

Interplay between MicroRNAs and Oxidative Stress in Neurodegenerative Diseases

MicroRNAs are post-transcriptional regulators of gene expression, crucial for neuronal differentiation, survival, and activity. Age-related dysregulation of microRNA biogenesis increases neuronal vulnerability to cellular stress and may contribute to the development and progression of neurodegenerative diseases. All major neurodegenerative disorders are also associated with oxidative stress, which is widely recognized as a potential target for protective therapies. Albeit often considered separately, microRNA networks and oxidative stress are inextricably entwined in neurodegenerative processes. Oxidative stress affects expression levels of multiple microRNAs and, conversely, microRNAs regulate many genes involved in an oxidative stress response. Both oxidative stress and microRNA regulatory networks also influence other processes linked to neurodegeneration, such as mitochondrial dysfunction, deregulation of proteostasis, and increased neuroinflammation, which ultimately lead to neuronal death. Modulating the levels of a relatively small number of microRNAs may therefore alleviate pathological oxidative damage and have neuroprotective activity. Here, we review the role of individual microRNAs in oxidative stress and related pathways in four neurodegenerative conditions: Alzheimer’s (AD), Parkinson’s (PD), Huntington’s (HD) disease, and amyotrophic lateral sclerosis (ALS). We also discuss the problems associated with the use of oversimplified cellular models and highlight perspectives of studying microRNA regulation and oxidative stress in human stem cell-derived neurons.

Allergy and Atopic Diseases: An Update on Experimental Evidence

Over the last decades, an increasing appearance of allergies and atopic disorders, such as asthma, dermatitis, and rhinitis, has been observed. The mechanisms of these disorders remain unclear, and therefore the development of novel therapies is limited. Current treatments are often symptomatic, nonspecific, or may have severe side effects. Further insights into the mechanisms of the underlying disease pathogenesis could reveal novel targets for treatment. In this review, we provide an update on recent basic and translational studies that offer novel insights and opportunities for the treatment of patients with atopic disorders.

Tangeretin promotes regulatory T cell differentiation by inhibiting Notch1/Jagged1 signaling in allergic rhinitis

BACKGROUND AND OBJECTIVE

Tangeretin demonstrates broad anti-inflammatory effects. The present study aimed to assess whether tangeretin functions in regulating T-regulatory cells (Tregs) and alleviating allergic rhinitis (AR).

METHODS

An ovalbumin (OVA)-induced AR animal model was constructed to monitor the changes in the allergic symptom score, OVA-specific IgE titers, histopathological characteristics and T-helper cell (Th1, Th2, and Th17)-related cytokine levels under tangeretin or dexamethasone (DXM) administration. The expression levels of Notch1/Jagged1 and FOXP3, and the proportion of Tregs in the spleens of these animals, were also detected. Furthermore, purified naive CD4 + T cells were utilized to assess the effects of tangeretin on Notch1 expression and their differentiation in vitro.

RESULTS

Both tangeretin and DXM administration alleviated airway inflammation, decreased the production of serum OVA-induced IgE, but only tangeretin administration restored the balance of cytokine profiles compared with those in the AR group. The abundance of splenic CD4 + CD25 + FOXP3 + Treg cells and the transcription factor FOXP3 were significantly increased under tangeretin treatment, either in AR mice or in naïve CD4 + T-cell differentiation, followed by a concomitant reduction in Notch1/Jagged1 expression. However, as a positive control, the treatment of allergic rhinitis with dexamethasone was not related to the expression of Notch1/Jagged1 or the differentiation of Treg cells.

CONCLUSION

Tangeretin could promote regulatory T cell responses by inhibiting Notch1/Jagged1 expression, followed by promoting FOXP3/Treg cell differentiation and thus could serve as a novel curative therapeutic for AR.