The In Vitro Impact of Glycyrrhizic Acid on CD4+ T Lymphocytes through OX40 Receptor in the Patients with Allergic Rhinitis

The potential application and molecular mechanisms of natural products in the treatment of allergic rhinitis: A review

BACKGROUNDS

Allergic rhinitis (AR) is a non-infectious chronic inflammation of the nasal mucosa mainly mediated by immunoglobulin E (IgE) in atopic individuals after exposure to allergens. The application of AR guideline-recommended pharmacotherapies can rapidly relieve symptoms of AR but with poor long-term efficacy, and many of these therapies have side effects. Many natural products and their derivatives have shown potential therapeutic effects on AR with fewer side effects.

OBJECTIVES

This review aims to expand understanding of the roles and mechanisms of natural compounds in the treatment of AR and to highlight the importance of utilizing natural products in the treatment of AR.

MATERIAL AND METHOD

We conducted a systematic literature search using PubMed, Web of Science, Google Scholar, and Clinical Trials. The search was performed using keywords including natural products, natural compounds, bioproducts, plant extracts, naturally derived products, natural resources, allergic rhinitis, hay fever, pollinosis, nasal allergy. Comprehensive research and compilation of existing literature were conducted.

RESULTS

This article provided a comprehensive review of the potential therapeutic effects and mechanisms of natural compounds in the treatment of AR. We emphasized that natural products primarily exert their effects by modulating signalling pathways such as NF-κB, MAPKs, STAT3/ROR-γt/Foxp3, and GATA3/T-bet, thereby inhibiting the activation and expansion of allergic inflammation. We also discussed their toxicity and clinical applications in AR therapy.

CONCLUSION

Taken together, natural products exhibit great potential in the treatment of AR. This review is also expected to facilitate the application of natural products as candidates for treating AR. Furthermore, drug discovery based on natural products has a promising prospect in AR treatment.

Apigenin attenuates inflammatory response in allergic rhinitis mice by inhibiting the TLR4/MyD88/NF-κB signaling pathway

BACKGROUND

Allergic rhinitis (AR) is an immunoglobulin E (IgE)-mediated immune inflammatory response that mainly affects the nasal mucosa. Currently, there is evidence that apigenin, as a flavonoid, has anti-allergic potential.

MATERIAL/METHODS

In vitro, compound 48/80 and lipopolysaccharide (LPS) were used to induce mast cell activation and inflammation in HMC-1 cells. In vivo, ovalbumin (OVA) induced and stimulated AR in BALB/c mice. ELISA was used to detect the contents of β-hexosaminidase, histamine, eosinophil cationic protein (ECP), OVA-specific IgE, IgG1, and IgG2a, inflammatory factors in cells and mouse serum. Cell viability and apoptosis were measured with MTT and flow cytometry. Toll like receptor 4 (TLR4)/myeloid differentiation factor88 (MyD88)/Nuclear transcription factor-κB (NF-κB) pathway-related proteins in cells and mouse nasal mucosa tissues were analyzed with Western blotting. The levels of Th1 (IFN-γ) and Th2 (IL-4, IL-5, and IL-13) cytokines and Th1 (T-bet) and Th2 (GATA-3) specific transcription factors were also assessed. The ratio of Th1 (CD4⁺ IFN-γ⁺ ) / Th2 (CD4⁺ IL-4⁺ ) cells in mouse peripheral blood mononuclear cells was evaluated by flow cytometry.

RESULTS

Apigenin significantly inhibited compound 48/80-induced secretion of β-hexosaminidase and histamine. Apigenin blocked LPS-induced decrease in cell viability and increase in cell apoptosis and inflammatory cytokine secretion by suppressing the activity of the TLR4/MyD88/NF-κB pathway. Apigenin treatment reduced the levels of OVA-specific IgE, IgG1 and IgG2a as well as β-hexosaminidase, histamine and ECP levels in mouse serum. Moreover, administration with apigenin decreased Th2 cytokine and transcription factor levels and increased Th1 cytokine and transcription factor levels, and promoted the ratio of Th1/Th2 cells in AR mice. Additionally, apigenin significantly alleviated nasal symptoms and nasal eosinophil infiltration in AR mice.

CONCLUSIONS

Apigenin alleviates the inflammatory response of allergic rhinitis by inhibiting the activity of the TLR4/MyD88/NF-κB signaling pathway.

Progress in preclinical studies of macrophage autophagy in the regulation of ALI/ARDS

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical clinical syndrome with high morbidity and mortality that poses a major challenge in critical care medicine. The development of ALI/ARDS involves excessive inflammatory response, and macrophage autophagy plays an important role in regulating the inflammatory response in ALI/ARDS. In this paper, we review the effects of autophagy in regulating macrophage function, discuss the roles of macrophage autophagy in ALI/ARDS, and highlight drugs and other interventions that can modulate macrophage autophagy in ALI/ARDS to improve the understanding of the mechanism of macrophage autophagy in ALI/ARDS and provide new ideas and further research directions for the treatment of ALI/ARDS.

Involvement of MicroRNA-27a-3p in the Licorice-Induced Alteration of Cd28 Expression in Mice

Licorice has previously been shown to affect gene expression in cells; however, the underlying mechanisms remain to be clarified. We analyzed the microRNA expression profile of serum from mice treated by gavage with licorice decoction, and obtained 11 differentially expressed microRNAs (DEmiRNAs). We also screened differentially expressed genes (DEgenes) based on RNA-Seq data, and 271 common genes were identified by intersection analysis of the predicted target genes of 11 DEmiRNAs and the DEgenes. The miRNA–gene network showed that most of the hub genes were immune-related. KEGG enrichment analysis of the 271 genes identified three significant pathways, and the 21 genes involved in these three pathways, and the 11 DEmiRNAs, were constructed into a miRNA pathway–target gene network, in which mmu-miR-27a-3p stood out. Compared to ImmPort, there were 13 immune genes within the above group of 21 genes, and three intersected with the mmu-miR-27a-3p predicted target genes, Cd28, Grap2 and Cxcl12, of which the expression of Cd28 changed most significantly. We confirmed the regulation of Cd28 by mmu-miR-27a-3p using a dual-luciferase assay, and further confirmed that overexpression of mmu-miR-27a-3p could significantly downregulate the expression of Cd28 in lymphocytes. These results indicate that mmu-miR-27a-3p could be involved in the licorice-mediated regulation of the expression of Cd28 in mice.

Preparation and Characterization of a Glycyrrhizic Acid-Based Drug Delivery System for Allergen-Specific Immunotherapy

The most effective method of treating allergic diseases, aimed not at relieving symptoms, but at eliminating the cause of the disease, is allergen-specific immunotherapy (AIT). To reduce the risk of side effects and improve the delivery of allergens to the mucosa, various delivery systems, such as liposomes, dendrimers, nanoparticles, etc., can be used. To date, there are data on the creation of delivery systems based on glycyrrhizic acid (GA) and its derivatives, but such a delivery system has not been used for allergen-specific therapy until now. It is also known that GA has an anti-inflammatory effect, shifts the balance towards Th1, and increases the number of Treg cells, meaning that it could potentially enhance the anti-allergic effect of AIT and reduce the risk of unwanted side effects. Thus, the study of the immunomodulatory effect of the supramolecular complexes (micelles) of GA with extracts of allergens holds promise for the development of new drugs for AIT.

Nasal irrigation with Glycyrrhiza glabra extract for treatment of allergic rhinitis - A study of in vitro, in vivo and clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhiza glabra, a family of licorice and a traditional Chinese medicine with sweet taste and favorable smell, has anti-inflammatory, anti-allergic and immunomodulatory functions.

AIM OF THE STUDY

We developed a licorice extract (LE) by using glycyrrhiza glabra and administered it through nasal irrigation to treat allergic rhinitis (AR).

MATERIALS AND METHODS

LE was prepared into extract powder, and the anti-inflammatory effect of the LE was evaluated by calcium ionophore-induced activated mast cell model (in vitro). Then, local passive anaphylaxis assays were applied to investigate the anti-IgE-mediated allergic reaction of the LE in mice (in vivo). A developed LE was administered through nasal irrigation to treat AR in clinic settings. A total of 60 participants diagnosed with AR were included in this clinical trial; they were randomly assigned to three interventions: licorice nasal irrigation (LNI), corticosteroid nasal irrigation (CNI), and saline nasal irrigation (SNI). They performed nasal irrigation once a day for 1 month. Both subjective questionnaires (22-item Sino-Nasal Outcome Test [SNOT-22] and visual analog scale [VAS]) and objective examinations (acoustic rhinometry and nasal endoscopy) were used for effectiveness assessments.

RESULTS

All three interventions could improve SNOT-22 scores, but the effects of LNI and CNI were more significant. According to VAS scores for nasal blockage, rhinorrhea, sneezing, nasal pruritus, postnasal discharge, and olfactory disturbance, the effect of LNI was superior to those of CNI and SNI. The results of rhinometry revealed that LNI significantly improved nasal resistance. Endoscopic analysis showed that both LNI and CNI, but not SNI, could significantly improve turbinate hypertrophy. Moreover, the best procedural comfort was found for LNI, which had no side effects or complications during the trial.

CONCLUSIONS

LNI is a natural, safe, and innovative therapy that can effectively treat AR. Its effect is superior to those of CNI and SNI, and it has greatly improved procedural comfort.

Glycyrrhizic acid restrains airway inflammation and remodeling in asthma via the TGF-β1/Smad signaling pathway

The anti-inflammatory effects of glycyrrhizic acid (GA) against asthma have previously been reported; however, the underlying molecular mechanism of GA in asthma has not yet been elucidated. Thus, the present study aimed to determine the function and potential molecular mechanism of GA for modulating the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway in asthma-associated airway inflammation and remodeling. In order to study the mechanism of GA on airway inflammation and airway remodeling in asthmatic mice, a mouse model of chronic asthma was constructed. A total of 50 female mice were randomly assigned into five groups (10 mice/group), as follows: Blank group, asthma group, GA group, dexamethasone group and GA + TGF-β1 group. Hematoxylin and eosin, and Masson staining were performed to assess the airway inflammation and remodeling in mice with ovalbumin (OVA)-induced asthma. The serum levels of interleukin (IL)-4, IL-5, IL-13 and IL-17 in mice were assessed via the enzyme-linked immunosorbent assay. Reverse transcription-quantitative PCR and western blot analyses were performed to detect the levels of TGF-β1 and Smads in lung tissues of each group of mice. The results demonstrated that GA and dexamethasone treatment mitigated airway inflammation, inflammatory cell infiltration and airway remolding, with a concomitant decrease in the expression levels of IL-4, IL-5, IL-13 and IL-17, in mice with OVA-induced asthma. In addition, the levels of TGF-β1 and Smad2 notably decreased, while Smad7 expression increased in the GA and dexamethasone groups compared with the asthma group. Furthermore, histopathological morphometry exhibited significantly elevated inflammatory cell infiltration, airway wall and smooth muscle, collagen secretion and inflammatory cytokines in the serum of mice in the GA + TGF-β1 group compared with the GA group. Taken together, the results of the present study suggest that GA ameliorates airway inflammation and remodeling via the TGF-β1/Smad signaling pathway in mice with asthma.

Review of Constituents and Biological Activities of Triterpene Saponins from Glycyrrhizae Radix et Rhizoma and Its Solubilization Characteristics

Glycyrrhizae Radix et Rhizoma is regarded as one of the most popular and commonly used herbal medicines and has been used in traditional Chinese medicine (TCM) prescriptions for over 2000 years. Pentacyclic triterpene saponins are common secondary metabolites in these plants, which are synthesized via the isoprenoid pathway to produce a hydrophobic triterpenoid aglycone containing a hydrophilic sugar chain. This paper systematically summarizes the chemical structures of triterpene saponins in Glycyrrhizae Radix et Rhizoma and reviews and updates their main biological activities studies. Furthermore, the solubilization characteristics, influences, and mechanisms of Glycyrrhizae Radix et Rhizoma are elaborated. Solubilization of the triterpene saponins from Glycyrrhizae Radix et Rhizoma occurs because they contain the nonpolar sapogenin and water-soluble sidechain. The possible factors affecting the solubilization of Glycyrrhizae Radix et Rhizoma are mainly other crude drugs and the pH of the decoction. Triterpene saponins represented by glycyrrhizin from Glycyrrhizae Radix et Rhizoma characteristically form micelles due to amphiphilicity, which makes solubilization possible. This overview provides guidance regarding a better understanding of GlycyrrhizaeRadix et Rhizoma and its TCM compatibility, alongside a theoretical basis for the further development and utilization of Glycyrrhizae Radix et Rhizoma.

Acupoint application inhibits nerve growth factor and attenuates allergic inflammation in allergic rhinitis model rats

Background

Acupoint application therapy (AAT) has been widely used to treat allergic inflammation induced by allergic rhinitis (AR). The therapeutic effect of acupoint application is obvious. But the underlying therapeutic mechanism is still indistinct. Nerve growth factor (NGF) expression showed a dramatic rise in nasal mucosa tissue after AR, and allergic inflammation also increased significantly. To demonstrate how AAT can improve allergic inflammation by down-regulating the expression of NGF, AR rat models were established by intraperitoneal injection of ovalbumin (OVA) and nasal drops in SD rats. The number of nasal rubbing, sneezing and the degree of runny nose were observed and the symptoms were scored by behavioral symptom scoring method within 3 min. The expression levels of NGF and its downstream key proteins, such as IL-4, IL-5, IL-13, IgE and IFN-γ were determined by q-PCR, Western blot analysis, ELISA and immunofluorescence staining. Furthermore, H&E staining and toluidine blue staining were used to observe the pathological structure of nasal mucosa and mast cells in nasal mucosa, and the ultrastructure of nasal mucosa was observed by electron microscopy.

Results

Our data demonstrated that acupoint application significantly reduced the score of behavioral symptoms, and decreased the expression levels of NGF and its downstream key proteins, including IL-4, IL-5, IL-13, IgE, as well as promoting the expression level of IFN-γ in nasal mucosa tissue in AR rats. Thus, the activation of IgE and viability of mast cells was inhibited.

Conclusion

Our findings suggest that AAT can attenuate allergic inflammation by inhibiting the expression of NGF and its downstream pathway.

Identification of a key candidate gene‑phenotype network mediated by glycyrrhizic acid using pharmacogenomic analysis

Glycyrrhizic acid (GA) is primarily used as an anti-inflammatory agent in cases of chronic hepatitis. However, its underlying mechanisms in diverse biological processes and its reported benefits are yet to be fully elucidated. In the current study, an analytical method based on pharmacogenomics was established to mine disease-modulatory activities mediated by GA. Five primary protein targets and 138 functional partners were identified for GA by querying open-source databases, including Drugbank and STRING. Subsequently, GA-associated primary and secondary protein targets were integrated into Cytoscape to construct a protein-protein interaction network to establish connectivity. GA-associated target genes were then clustered based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. The tumor necrosis factor axis was revealed to be a primary module regulated by GA-associated targets. Furthermore, 12 hub genes were queried to assess their potential anti-cancer effects using cBioPortal. The results indicated that pharmacogenomics-based analysis improved understanding of the underlying drug-target events of GA and provided predictive and definitive leads for future studies.