Increased expression of toll-like receptors 2 and 4 and related cytokines in persistent allergic rhinitis

Integration of bioinformatics analysis, molecular docking and animal experiments to study the therapeutic mechanisms of berberine against allergic rhinitis

Allergic rhinitis is a prevalent inflammatory condition that impacts individuals of all age groups. Despite reports indicating the potential of berberine in alleviating allergic rhinitis symptoms, the specific molecular mechanisms and therapeutic targets of berberine remain unclear. This research aims to explore the pharmacological mechanism of berberine in the treatment of allergic rhinitis through bioinformatic analyses and experimental validation. The research utilized public databases to identify potential targets of berberine. Furthermore, differentially expressed genes (DEGs) related to allergic rhinitis were pinpointed from the GSE52804 dataset. Through bioinformatics techniques, the primary targets were discovered and key KEGG and GO-BP pathways were established. To confirm the therapeutic mechanisms of berberine on allergic rhinitis, an OVA-induced allergic rhinitis model was developed using guinea pigs. We identified 32 key genes responsible for the effectiveness of berberine in treating allergic rhinitis. In addition, five central genes (Alb, Il6, Tlr4, Ptas2, and Il1b) were pinpointed. Further examination using KEGG and GO-BP pathways revealed that the main targets were primarily involved in pathways such as NF-kappa B, IL-17, TNF, and inflammatory response. Molecular docking analysis demonstrated that berberine exhibited strong affinity towards these five key targets. Furthermore, the expression levels of IL-6, TLR4, PTGS2, and IL-1β were significantly upregulated in the model group but downregulated following berberine treatment. This research has revealed the mechanism through which berberine combats allergic rhinitis and has identified its potential to regulate pathways linked to inflammation. These discoveries provide valuable insights for the development of novel medications for the treatment of allergic rhinitis.

The Assessment of TLR1 Gene Polymorphism Association with the Risk of Allergic Rhinitis in the Chinese Han Population from Northern China

Background

Environmental factors and genetic predisposition can influence the occurrence and development of AR. Toll-like receptor 1 (TLR1) belongs to the TLR receptor family, which plays a fundamental role in the activation of innate immunity. This study aimed to explore the association between TLR1 genetic loci and AR susceptibility in the Han Chinese from northern China.

Methods

Genotyping of three SNPs in the TLR1 has proceeded using the Agena MassARRAY platform. Odds ratio (OR) and 95% confidence interval (CI) were used to assess the correlation between candidate SNPs and AR susceptibility. Using FPRP (false-positive report probability analysis) to detect whether the positive results are noteworthy findings. The SNP-SNP interactions were detected by multifactor dimensionality reduction (MDR).

Results

TLR1-rs72493538 (Allele "G": OR=0.77, p = 0.034) and -rs76600635 (Allele "G": OR=0.75, p = 0.024) were associated with reducing the risk of AR among Han Chinese in northern China. In addition, we found evidence that TLR1-rs72493538 (males, participants with aging > 43 years, or coming from the wind-blown sand region) and -rs76600635 (males, participants with BMI ≤ 24 kg/m2, or coming from the wind-blown sand region) were associated with AR risk in stratified analyses. FPRP showed that all positive results are noteworthy findings. MDR analysis showed that a two-loci genetic model composed of rs72493538 and rs76600635 can be chosen as the best genetic model to predict the risk of AR.

Conclusion

TLR1-rs72493538 and -rs76600635 have a close association with reducing the risk of AR.

When the allergy alarm bells toll: The role of Toll-like receptors in allergic diseases and treatment

Toll-like receptors of the human immune system are specialized pathogen detectors able to link innate and adaptive immune responses. TLR ligands include among others bacteria-, mycoplasma- or virus-derived compounds such as lipids, lipo- and glycoproteins and nucleic acids. Not only are genetic variations in TLR-related genes associated with the pathogenesis of allergic diseases, including asthma and allergic rhinitis, their expression also differs between allergic and non-allergic individuals. Due to a complex interplay of genes, environmental factors, and allergen sources the interpretation of TLRs involved in immunoglobulin E-mediated diseases remains challenging. Therefore, it is imperative to dissect the role of TLRs in allergies. In this review, we discuss i) the expression of TLRs in organs and cell types involved in the allergic immune response, ii) their involvement in modulating allergy-associated or -protective immune responses, and iii) how differential activation of TLRs by environmental factors, such as microbial, viral or air pollutant exposure, results in allergy development. However, we focus on iv) allergen sources interacting with TLRs, and v) how targeting TLRs could be employed in novel therapeutic strategies. Understanding the contributions of TLRs to allergy development allow the identification of knowledge gaps, provide guidance for ongoing research efforts, and built the foundation for future exploitation of TLRs in vaccine design.

A review of recent advances in exosomes and allergic rhinitis

Allergic rhinitis is a chronic inflammatory disease of nasal mucosa caused by the presence of IgE after exposure to allergens, characterized by nasal irritation, hypersecretion of the nasal passages and sneezing, which frequently occurs in children and adolescents. There has been an increase in allergic rhinitis over the past few years due to air pollution. Exosomes have been discovered to be nano-sized vesicles, which contain a wide range of substances, including proteins and nucleic acids, numerous studies indicates that exosomes play a vital role in cells communication. Recently there have been more and more studies exploring the role of exosomes in allergic rhinitis. Therefore, here we will present a comprehensive review of the research on exosomes and their role in allergic rhinitis for the purpose of providing new understanding of potential value of exosomes applied to the treatment of allergic rhinitis.

The Effects of Saposhnikovia divaricata Aqueous Extracts on the Inflammation and Intestinal Microflora in Allergic Rhinitis Mice

Background

Allergic rhinitis (AR) is a type I allergic disease induced by IgE. Traditional Chinese medicine Saposhnikovia divaricata (Turcz.) Schischk (SD) has anti-inflammatory and antiallergic effects.

Materials and Methods

AR model mice were constructed with ovalbumin (OVA) sensitization to observe the improving effect of SD treatment on AR by counting the number of sneezing and rubbing the nose, hematoxylin-eosin, periodic acid-Schiff, and toluidine blue stains. In addition, the allergy and inflammatory cytokines levels and inflammatory cells were observed by ELISA and Wright's-Giemsa stain. The protein levels of the TLR4/TRAF6/NF-κB and IL-6/ROR-γt/STAT3 pathways were measured by immunohistochemistry, quantitative real-time PCR, and western blot. The intestinal microflora abundance in mice was observed by 16S rDNA high-throughput sequencing.

Results

SD treatment inhibited the sneezing and rubbing times of the nose, decreased the degree of a dense arrangement of cells and mucosal swelling and the number of goblet and mast cells of nasal lavage fluid, reduced the levels of IgE, histamine, Leukotriene B4, IL-4, IL-5, TNF-α, IL-6, and IL-17, the eosinophils, neutrophils, and lymphocytes number, the LR4, TRAF6, IL-6, ROR-γt, and STAT3 mRNA levels, respectively, while, it increased the IL-2, IL-10, IFN-γ, and TGF-β1 proteins. SD treatment inhibited the NF-κB, p-STAT3, TLR4, TRAF6, and p-IκBα/IκBα proteins. Besides, the effects of OVA and SD treatments were significantly correlated with the abundance of intestinal microflora. The abundances of Cytophagales, Burkholderia, Alteromonadales, Lactococcus, and Clostridiaceae were changed in SD treatment on AR mice.

Conclusions

This study provides a possibility that the improvement effect of SD treatment on allergies and inflammation in AR mice may be related to the TLR4/TRAF6/NF-κB and IL-6/ROR-γt/STAT3 pathways and intestinal microflora modulation.

Cell-Type Specific Expression of Hyaluronan Synthases HAS2 and HAS3 Promotes Goblet Cell Hyperplasia in Allergic Airway Inflammation

Allergic rhinitis (AR) is a multifactorial airway disease characterized by basal and goblet cell hyperplasia. Hyaluronic acid (HA) is a major component of extracellular matrix and a critical contributor to tissue repair and remodeling after injury. We previously demonstrated that the intermediate progenitor cell (IPC) surface marker CD44v3 is upregulated in the basal and suprabasal layers of well-differentiated primary human nasal epithelial (HNE) cells after stimulation with the Th2 cytokine interleukin (IL)-4, and an antibody blocking the CD44v3-HA interaction suppressed IL-4-induced goblet cell hyperplasia. We now show that the expression of HA and two HA synthases, HAS2 and HAS3, was upregulated in both the nasal surface epithelium of subjects with AR and IL-4-stimulated HNE cells. Inhibition of HA synthesis by 4-methylumbelliferone (4-MU) suppressed IL-4-induced goblet cell hyperplasia. Moreover, HAS2 and HAS3 were expressed in IPCs depending on the differentiation events, as follows: the rapid, transient upregulation of HAS2 induced basal IPC proliferation and basal-to-suprabasal transition, whereas the delayed upregulation of HAS3 promoted the transition of suprabasal IPCs to a goblet cell fate. 4-MU treatment in house dust mite-induced murine AR model attenuated goblet cell metaplasia. Lastly, HA levels in nasal epithelial lining fluids from AR patients positively correlated with the levels of mediators causing allergic inflammation. These data suggest that HA produced following the sequential upregulation of HAS2 and HAS3 contributes to goblet cell hyperplasia in allergic airway inflammation and modulates disease progression.

Astragaloside IV suppresses histamine-induced inflammatory factors and mucin 5 subtype AC overproduction in nasal epithelial cells via regulation of inflammation-related genes

Allergic rhinitis (AR) is a symptomatic allergic disease that leads to severe inflammation. Astragaloside IV (AS-IV) is a primary active component of Astragalus membranaceus and exerts immune-regulation and anti-inflammatory effects. However, the pharmacological effect of AS-IV in the nasal epithelial cells (NECs) has not been reported. The present study aimed to assess the effect of AS-IV on inflammatory cytokines and mucin 5 subtype AC (MUC5AC) overproduction in histamine (His)-stimulated NECs and its underlying mechanism. NECs were stimulated with or without His for 24 h in the absence or presence of AS-IV. The levels of inflammatory cytokines including IL-6, IL-8, MCP-1, IL-1β, granulocyte-macrophage colony-stimulating factor (GM-CSF), eotaxin, and MUC5AC were assayed. Our findings indicated that AS-IV inhibited His-evoked release and expression of inflammatory cytokines and MUC5AC in NECs. RNA-seq analyses indicated the significant changes in expression levels involved in inflammation genes upon treatment of His-induced NECs with AS-IV. Our findings indicated that AS-IV inhibited His-evoked inflammatory cytokines secretion and MUC5AC overproduction in NECs, which were partly mediated by regulation of inflammation-related genes. Therefore, our findings provided a scientific basis for the development of AS-IV as an effective agent for clinical therapeutic strategy in the treatment of AR.

Birch Pollen Induces Toll-Like Receptor 4-Dependent Dendritic Cell Activation Favoring T Cell Responses

Seasonal exposure to birch pollen (BP) is a major cause of pollinosis. The specific role of Toll-like receptor 4 (TLR4) in BP-induced allergic inflammation and the identification of key factors in birch pollen extracts (BPE) initiating this process remain to be explored. This study aimed to examine (i) the importance of TLR4 for dendritic cell (DC) activation by BPE, (ii) the extent of the contribution of BPE-derived lipopolysaccharide (LPS) and other potential TLR4 adjuvant(s) in BPE, and (iii) the relevance of the TLR4-dependent activation of BPE-stimulated DCs in the initiation of an adaptive immune response. In vitro, activation of murine bone marrow-derived DCs (BMDCs) and human monocyte-derived DCs by BPE or the equivalent LPS (nLPS) was analyzed by flow cytometry. Polymyxin B (PMB), a TLR4 antagonist and TLR4-deficient BMDCs were used to investigate the TLR4 signaling in DC activation. The immunostimulatory activity of BPE was compared to protein-/lipid-depleted BPE-fractions. In co-cultures of BPE-pulsed BMDCs and Bet v 1-specific hybridoma T cells, the influence of the TLR4-dependent DC activation on T cell activation was analyzed. In vivo immunization of IL-4 reporter mice was conducted to study BPE-induced Th2 polarization upon PMB pre-treatment. Murine and human DC activation induced by either BPE or nLPS was inhibited by the TLR4 antagonist or by PMB, and abrogated in TLR4-deficient BMDCs compared to wild-type BMDCs. The lipid-free but not the protein-free fraction showed a reduced capacity to activate the TLR4 signaling and murine DCs. In human DCs, nLPS only partially reproduced the BPE-induced activation intensity. BPE-primed BMDCs efficiently stimulated T cell activation, which was repressed by the TLR4 antagonist or PMB, and the addition of nLPS to Bet v 1 did not reproduce the effect of BPE. In vivo, immunization with BPE induced a significant Th2 polarization, whereas administration of BPE pre-incubated with PMB showed a decreased tendency. These findings suggest that TLR4 is a major pathway by which BPE triggers DC activation that is involved in the initiation of adaptive immune responses. Further characterization of these BP-derived TLR4 adjuvants could provide new candidates for therapeutic strategies targeting specific mechanisms in BP-induced allergic inflammation.

CircRNA expression profiles and circRNA-miRNA-mRNA crosstalk in allergic rhinitis

Background

Circular RNAs (circRNAs) are involved in inflammation; however, their role in allergic rhinitis (AR) remains unclear. In this study, we analyzed circRNA expression and identified a circRNA-miRNA-mRNA network through which circRNAs regulate AR pathogenesis.

Methods

We analyzed circRNA, miRNA, and mRNA expression profiles in the nasal mucosa by high-throughput sequencing (HTS), using a fold-change >1.5 and p-value < 0.05 to pinpoint significantly differentially expressed (DE) circRNAs, miRNAs, and mRNAs in AR. A DEcircRNA-DEmiRNA-DEmRNA crosstalk network was then constructed using bioinformatics and statistical analysis. Gene ontology and Kyoto encyclopedia of genes and genomes pathway analyses were performed to identify the biological terms enriched in the network; whereas RT-PCR and Sanger sequencing were used to confirm the circRNAs.

Results

A total of 264 DEcircRNAs were identified by HTS, including 120 upregulated and 144 downregulated in AR compared to controls. A DEcircRNA-DEmiRNA-DEmRNA crosstalk network was constructed with 17 miRNAs, 11 circRNAs, 29 mRNAs, and 64 interaction pairs. These genes were involved in the Wnt signaling pathway, TNF biosynthesis, inflammatory responses, the PI3K-Akt signaling pathway, and Toll-like receptors. Of the 11 DEcircRNAs, hsa_circ_0008668 and circTRIQK were upregulated, whereas hsa_circ_0029853 and circRNA_01002 were downregulated in AR tissues. Sanger sequencing confirmed the back-splicing junctions of these circRNAs.

Conclusions

We constructed a novel DEcircRNA-DEmiRNA-DEmRNA network for AR that provides a basis for future studies to investigate its underlying molecular mechanisms.

Glycated Albumin Triggers an Inflammatory Response in the Human Airway Epithelium and Causes an Increase in Ciliary Beat Frequency

The role of inflammation in airway epithelial cells and its regulation are important in several respiratory diseases. When disease is present, the barrier between the pulmonary circulation and the airway epithelium is damaged, allowing serum proteins to enter the airways. We identified that human glycated albumin (GA) is a molecule in human serum that triggers an inflammatory response in human airway epithelial cultures. We observed that single-donor human serum induced IL-8 secretion from primary human airway epithelial cells and from a cystic fibrosis airway cell line (CF1-16) in a dose-dependent manner. IL-8 secretion from airway epithelial cells was time dependent and rapidly increased in the first 4 h of incubation. Stimulation with GA promoted epithelial cells to secrete IL-8, and this increase was blocked by the anti-GA antibody. The IL-8 secretion induced by serum GA was 10–50-fold more potent than TNF_α or LPS stimulation. GA also has a functional effect on airway epithelial cells in vitro, increasing ciliary beat frequency. Our results demonstrate that the serum molecule GA is pro-inflammatory and triggers host defense responses including increases in IL-8 secretion and ciliary beat frequency in the human airway epithelium. Although the binding site of GA has not yet been described, it is possible that GA could bind to the receptor for advanced glycated end products (RAGE), known to be expressed in the airway epithelium; however, further experiments are needed to identify the mechanism involved. We highlight a possible role for GA in airway inflammation.

The SP-TLR axis, which locally primes the nasal mucosa, is impeded in patients with allergic rhinitis

Background

Substance P (SP) and toll‐like receptors (TLRs) contribute to airway disease, particularly during viral infection. We recently demonstrated that SP can act as an initial response to viral stimuli in the upper airway by upregulating TLRs in the nasal epithelia (the SP‐TLR axis). Patients with allergic rhinitis (AR) suffer from prolonged airway infections. The aim of the present study was to examine if patients with AR exhibit a disturbance in the SP‐TLR axis.

Method

Human nasal biopsies and human nasal epithelial cells (HNEC) from healthy volunteers and patients with AR were cultured in the presence of SP. Epithelial expression of TLR4, neutral endopeptidase (NEP) and neurokinin 1 (NK1) were evaluated with flow cytometry and/or quantitative polymerase chain reaction after 30 min to 24 h. The effect of SP on nasal lipopolysaccharide‐induced interleukin‐8 (IL‐8) release was investigated.

Results

SP stimulation of tissue from healthy volunteers resulted in a transient increase of the TLR4 expression, whereas stimulation of AR patient‐derived material led to a delayed and prolonged upregulation of TLR4. NEP expression in HNEC was lower in AR than healthy controls whereas NK1 receptor expression was increased. SP pretreatment increased TLR4‐dependent IL‐8 expression in healthy controls, but not in AR.

Conclusions

SP‐induced regulation of TLR4 in the human nasal mucosa is disturbed in AR. An altered SP‐mediated innate immune response may contribute to the dysfunctional and often prolonged responses to infection in AR.

MicroRNA-182-5p relieves murine allergic rhinitis via TLR4/NF-κB pathway

Allergic rhinitis (AR) is one of the most common chronic diseases. This study examined whether microRNA (miR)-182-5p plays a role in AR by regulating toll-like receptor 4 (TLR4). First, data demonstrated that TLR4 was a target of miR-182-5p. Subsequently, AR mouse model was established to explore the role of miR-182-5p and TLR4 in AR in vivo. Initially, quantitative reverse transcription-PCR (qRT-PCR) analysis indicated that miR-182-5p was downregulated, while TLR4 expression was upregulated in AR mice. Then we found that miR-182-5p mimic reduced the frequency of sneezing and nose rubbing of the AR mice. In addition, miR-182-5p mimic significantly increased ovalbumin (OVA)-specific IgE and leukotriene C4 expression levels in nasal lavage fluid (NLF) and serum of AR mice. miR-182-5p mimic decreased the number of inflammatory cells in NLF of AR mice. It also reduced the levels of inflammatory factors in the serum of AR mice, such as interleukin (IL)-4, IL-5, IL-13, IL-17 and tumor necrosis factor (TNF)-α, while increasing the release of IFN-γ and IL-2. Finally, miR-182-5p mimic inhibited NF-κB signaling pathway activation in AR mice. However, all effects of miR-182-5p mimic on AR mice were reversed by TLR4-plasmid. In conclusion, miR-182-5p/TLR4 axis may represent a novel therapeutic target for AR.

Toll-Like Receptor Agonists as Adjuvants for Allergen Immunotherapy

Toll-like receptors (TLRs) are essential components of innate immunity and provide defensive inflammatory responses to invading pathogens. Located within the plasma membranes of cells and also intracellular endosomes, TLRs can detect a range of pathogen associated molecular patterns from bacteria, viruses and fungi. TLR activation on dendritic cells can propagate to an adaptive immune response, making them attractive targets for the development of both prophylactic and therapeutic vaccines. In contrast to conventional adjuvants such as aluminium salts, TLR agonists have a clear immunomodulatory profile that favours anti-allergic T lymphocyte responses. Consequently, the potential use of TLRs as adjuvants in Allergen Immunotherapy (AIT) for allergic rhinitis and asthma remains of great interest. Allergic Rhinitis is a Th2-driven, IgE-mediated disease that occurs in atopic individuals in response to exposure to otherwise harmless aeroallergens such as pollens, house dust mite and animal dander. AIT is indicated in subjects with allergic rhinitis whose symptoms are inadequately controlled by antihistamines and nasal corticosteroids. Unlike anti-allergic drugs, AIT is disease-modifying and may induce long-term disease remission through mechanisms involving upregulation of IgG and IgG4 antibodies, induction of regulatory T and B cells, and immune deviation in favour of Th1 responses that are maintained after treatment discontinuation. This process takes up to three years however, highlighting an unmet need for a more efficacious therapy with faster onset. Agonists targeting different TLRs to treat allergy are at different stages of development. Synthetic TLR4, and TLR9 agonists have progressed to clinical trials, while TLR2, TLR5 and TLR7 agonists been shown to have potent anti-allergic effects in human in vitro experiments and in vivo in animal studies. The anti-allergic properties of TLRs are broadly characterised by a combination of enhanced Th1 deviation, regulatory responses, and induction of blocking antibodies. While promising, a durable effect in larger clinical trials is yet to be observed and further long-term studies and comparative trials with conventional AIT are required before TLR adjuvants can be considered for inclusion in AIT. Here we critically evaluate experimental and clinical studies investigating TLRs and discuss their potential role in the future of AIT.

Relationship between chemokines and T lymphocytes in the context of respiratory allergies (Review)

Allergic diseases have been classified in the last decades using various theories. The main classes of the newest classification in allergic respiratory diseases focus on the characterization of the endotype (which takes into account biomarkers related to determinant pathophysiological mechanisms) and of the phenotype (based on the description of the disease). Th2, Th1 and Th17 lymphocytes and the type of inflammatory response mediated by them represent the basis for Th2 and non-Th2 endotype classification. In addition, new lymphocytes were also used to characterize allergic diseases: Th9 lymphocytes, Th22 lymphocytes, T follicular helper cells (T_FH) lymphocytes and invariant natural killer T (iNKT) lymphocytes. In the last decade, a growing body of evidence focused on chemokines, chemoattractant cytokines, which seems to have an important contribution to the pathogenesis of this pathology. This review presents the interactions between chemokines and Th lymphocytes in the context of Th2/non-Th2 endotype classification of respiratory allergies.

Esculetin inhibits histamine-induced expression of inflammatory cytokines and mucin in nasal epithelial cells

Allergic rhinitis (AR) is a type of respiratory disease closely associated with chronic inflammation. Esculetin is a natural coumarin derivative and has been reported to possess anti-allergic and anti-inflammatory effects. However, the roles of esculetin in AR have not been studied. In this study, we aimed to examine the effect of esculetin on AR using an in vitro model. The human nasal epithelial cells (HNEpC) were stimulated by histamine for 24 hours with or without the pretreatment of esculetin. The mRNA levels and production of inflammatory cytokines including IL-6 and IL-8, as well as mucin 5AC (MUC5AC) were measured using qRT-PCR and ELISA, respectively. The results showed that esculetin suppressed histamine-induced expression and secretion of IL-6, IL-8, and MUC5AC in HNEpCs. Furthermore, we examined the effect of esculetin on NF-κB pathway by detecting the expression levels of NF-κB p65, p-p65 and IκBα using western blot analysis. Esculetin treatment suppressed the histamine-induced p-p65 expression and p-IκBα degradation. Inhibiting NF-κB pathway suppressed histamine-induced production of IL-6, IL-8, and MUC5AC in HNEpCs. These findings suggested that esculetin suppressed histamine-induced production of inflammatory cytokines and mucin in HNEpCs, which were partly mediated by the inhibition of NF-κB pathway.

Inhibition of TLR4 inhibits allergic responses in murine allergic rhinitis by regulating the NF-κB pathway

The present study investigated the underlying mechanisms and effects of toll-like receptor 4 (TLR4) on a mouse model of allergic rhinitis (AR). An ovalbumin (OVA)-induced mouse model of AR was treated with TLR4-short hairpin RNA (shRNA). Allergic symptoms were then subsequently assessed. Protein levels of OVA-specific immunoglobulin E (IgE), eosinophil cation protein (ECP), leukotriene C4 (LTC4) and prostaglandin D2 (PGD2) in mice serum and nasal lavage fluid, as well as various inflammatory cytokine mediators in mice serum, were determined by ELISA. Protein level detection was performed using reverse transcription-quantitative PCR and western blot analysis. The results revealed that TLR4 was highly expressed in the nasal mucosa of AR mice. TLR4 inhibition significantly relieved OVA-induced AR symptoms. Relief of symptoms was evidenced by a decreased frequency of sneezing and nose friction, reduced levels of OVA-specific IgE, ECP, LTC4, PGD2, less inflammatory cells and decreased levels of T-helper 2 type cytokines. In addition, the data indicated that OVA-induced activation of the NF-κB pathway was repressed by TLR4-shRNA. The results of the current study indicate that TLR4 may be a promising therapeutic target of AR.

Superior effect of MP-AzeFlu than azelastine or fluticasone propionate alone on reducing inflammatory markers

BACKGROUND

MP-AzeFlu, intranasal formulation of azelastine hydrochloride (AZE) and fluticasone propionate (FP), is superior to AZE or FP alone for treatment of allergic rhinitis (AR). However, the precise anti-inflammatory mechanism of action of MP-AzeFlu has not been characterized.

OBJECTIVE

To investigate the anti-inflammatory effects of MP-AzeFlu compared with AZE or FP alone in an established in vitro model of eosinophilic inflammation.

METHODS

Nasal mucosal epithelial cells and peripheral blood eosinophils were obtained from human volunteers. Epithelial cells were stimulated with 10% fetal bovine serum (FBS) in the presence of MP-AzeFlu, AZE, or FP (1:102 to 1:105 dilution). Concentrations of interleukin (IL)-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) were measured by ELISA. Eosinophils were incubated in 10% human epithelial cell-conditioned medium (HECM) and survival assessed by trypan blue dye exclusion. Results are expressed as mean ± SEM percentage secretion/survival compared with FBS/HECM (respectively).

RESULTS

FP and MP-AzeFlu (all dilutions) and AZE (1:102) significantly reduced IL-6 secretion and eosinophil survival compared with positive controls. At 1:102 dilution, IL-6 secretion was significantly lower with MP-AzeFlu (38.3 ± 4.2%, compared with FBS = 100%) than with AZE (76.1 ± 4.9%) or FP (53.0 ± 4.9%). At 1:102 dilution, eosinophil survival was significantly lower with MP-AzeFlu at day 3 (17.5 ± 3.0%) and day 4 (2.4 ± 1.4%, compared with HECM = 100%) than with AZE (day 3: 75.2 ± 7.2%; day 4: 44.0 ± 9.7%) or FP (day 3: 38.5 ± 3.5%; day 4: 14.6 ± 4.0%).

CONCLUSION

Greater reductions in cytokine secretion and eosinophil survival observed with MP-AzeFlu in vitro may underlie MP-AzeFlu's superior clinical efficacy vs. AZE or FP alone observed in AR patients.

Effects of Aspergillus fumigatus on glucocorticoid receptor and β2-adrenergic receptor expression in a rat model of asthma

PURPOSE

Conventional inhaled corticosteroids or β2-adrenergic receptor agonists do not work well in some asthmatic populations while empirical antifungal therapy has obvious impact on those patients. The study was designed to investigate whether short-term exposure to Aspergillus fumigatus (A. fumigatus) could decrease glucocorticoid receptor (GCR) and β2-adrenergic receptor (ADRB2) expression in lung tissue of asthmatic rats.

MATERIALS AND METHODS

A rat model of chronic asthma was first established by ovalbumin sensitization and challenge. Rats with chronic asthma were then exposed to short-term application of A. fumigatus spores. Airway hyper-responsiveness, eosinophil ratio in bronchoalveolar lavage (BAL) fluid and total IgE in serum were counted in these experimental animals. GCR and ADRB2 expression in the lung were detected and analyzed. Furthermore, the levels of toll-like receptors (TLRs) 2, 3 and 4 in lung tissue were measured.

RESULTS

Short-term exposure to A. fumigatus could down-regulate the expression of GCR, aggravate airway hyper-responsiveness and increase the level of TLR2 in rats with asthma. There were no obvious changes in the levels of ADRB2 expression, recruited eosinophils, total IgE, TLR3 and TLR4 after application of A. fumigatus in asthmatic rats.

CONCLUSIONS

These findings indicate that A. fumigatus exposure may be involved in glucocorticoids unresponsiveness by down-regulating the expression of GCR in asthmatics. The possibility of A. fumigatus colonization or infection should not be ignored in patients of steroid-resistant asthma.

mRNA-Mediated Gene Supplementation of Toll-Like Receptors as Treatment Strategy for Asthma In Vivo

Asthma is the most common chronic disease in childhood. Although several therapeutic options are currently available to control the symptoms, many drugs have significant side effects and asthma remains an incurable disease. Microbial exposure in early life reduces the risk of asthma and several studies have suggested protective effects of Toll-like receptor (TLR) activation. We showed previously that modified mRNA provides a safe and efficient therapeutic tool for in vivo gene supplementation. Since current asthma drugs do not take patient specific immune and TLR backgrounds into consideration, treatment with tailored mRNA could be an attractive approach to account for the patient's individual asthma phenotype. Therefore, we investigated the effect of a preventative treatment with combinations of Tlr1, Tlr2 and Tlr6 mRNA in a House Dust Mite-induced mouse model of asthma. We used chemically modified mRNA which is-in contrast to conventional viral vectors-non-integrating and highly efficient in gene transfer. In our study, we found that treatment with either Tlr1/2 mRNA or Tlr2/6 mRNA, but not Tlr2 mRNA alone, resulted in better lung function as well as reduced airway inflammation in vivo. The present results point to a potentially protective effect of TLR heterodimers in asthma pathogenesis.