AR is a serious disease encountered in the human population, and its prevention and treatment options are limited. It is, therefore, important to find and validate candidate drugs for this disease. Past research indicated the potential of Huangqi in the treatment of AR. However, the therapeutic mode of action of Huangqi in AR has to be clarified. Herein, we intended to pinpoint the bioactive components of Huangqi in AR therapy by network pharmacology and examine their possible molecular mechanism. We screened 76 bioactive components in Huangqi, targeting 62 genes related to the pathogenesis of AR. Among these bioactive components, QUE was found to have the highest number of targets (41 targets) in AR treatment, showing that QUE may be used as a key drug for treating AR. Based on the 62 QUE targets, the PPI network indicated RELA, JUN, NFKBIA, IRF1, and IFNG as the key hub genes. The 34 hub targets of QUE were those participating in biological processes related to biosynthetic, immune, and inflammation processes. Experimentally, we demonstrated that Huangqi or QUE alleviate inflammation associated with AR via regulating RELA/IFNG/IRF1 axis. Our study is the first pharmacological network analysis demonstrating the molecular mechanism of Huangqi effectiveness against AR, shedding light on the mode of action of Huangqi and QUE in the treatment of AR.
The scientific study on the efficiency of TCM to treat AR has yielded positive results. Data suggests that incorporating TCM practices, such as herbal remedies and acupuncture, can significantly improve AR symptoms, including congestion and runny nose (Sun et al., 2016, Shou et al., 2020, Ding et al., 2021). The effect of TCM treatments can offer sustained relief, with symptoms subsiding for up to a year following treatment (Yang et al., 2021, Zhang et al., 2023). Of significance, TCM therapies demonstrate minimal side effects and are well-received by patients (Zhang et al., 2020). Thus, the application of TCM in alleviating AR may be a safe and effective additional therapy for individuals seeking allergy symptom relief (Zhang et al., 2020). Emerging research suggests that Huangqi may hold significant promise in managing AR symptoms. Indeed, a previous study indicated that Huangqi contains anti-allergic components (Lv et al., 2017). Another study discovered that Huangqi extract significantly alleviated nasal symptoms, including sneezing and congestion, in patients with AR (Matkovic et al., 2010). These studies indicate that Huangqi might serve as a valuable supplement to conventional AR treatments. However, despite this potential, network analysis of Huangqi in human diseases has yet to be conducted. In this study, we conducted network pharmacology to elucidate, for the first time, the mechanism of Huangqi in AR. We found that the therapeutic mechanism of Huangqi is driven by its components that target genes mainly responsible for positive regulation of cellular biosynthetic process. When an allergen triggers the immune system, it produces IgE, leading to a chain reaction of histamine release in the nasal tissues, triggering symptoms such as sneezing, itching, and congestion in AR (Justiz Vaillant et al., 2023, Kumari et al., 2023). Thus, by targeting the biosynthetic processes, Huangqi can perturb the disturbances associated with AR, resulting in efficient treatments of AR. Our research also showed that Huangqi mainly targets immune- and inflammation-related pathways such as IL − 12 Signaling and Production in Macrophages, and Role of Macrophages. Experimentally, we found that Huangqi counteracted the effect of AR on the levels of cytokines such as IL-13, IL-4, TNF-α, IL-5 and IFNG, confirming its anti-inflammatory and immune-regulating properties. This finding is supported by a previous study indicating that Huangqi-Guizhi-Wuwu decoction is effective in regulating the differentiation of CD4(+) T cell and preventing the progression of experimental autoimmune encephalomyelitis in mice (Xu et al., 2024).
QUE, a flavonoid compound, is commonly encountered in a variety of fruits and vegetables. Through consistent research findings, QUE has been shown to offer therapy and protection properties against various human conditions. In the present study, we found that QUE was the component of Huangqi with the highest number of targets as AR-related genes. Experimentally, the effect of QUE was similar to that of Huangqi on AR-associated inflammation and pathological changes. This anti-AR properties of QUE has been reported in previous studies. In fact, it was previously reported that AR can be alleviated by applying QUE, which contributes in restoring the balance of the Treg/Th17 cells and Th1/Th2 cells (Ke et al., 2023). A clinical study indicated that repeated oral intake of a quercetin-containing supplement can effectively reduce allergic reaction (Yamada et al., 2022). The PPI network established from the 62 QUE targets has revealed important hub genes, including RELA, JUN, NFKBIA, IRF1, and IFNG. RELA and JUN coordinate gene expression, whereas NFKBIA serves as a restrictive agent in the NF-κB pathway. IRF1 regulates immune responses, while IFNG participates in innate and adaptive immune responses. The targeting of these critical genes implies that QUE may influence their activity to produce therapeutic effects through associated pathways.
The NF-κB pathway is crucial for immune homeostasis. The RELA subunit of NF-κB is responsible for the transcriptional activation of pro-inflammatory genes, and its activity is tightly controlled by various mechanisms to prevent excessive inflammation and ensure proper immune responses. RELA has been reported to be significantly involved in AR. For instance, it was reported that miR-302e hinders allergic inflammation via inhibiting NF-kB activation by targeting RELA (Xiao et al., 2018). Moreover, fucoxanthin was reported to alleviate Ovalbumin-Induced AR via RELA and STAT3 Signaling (Li et al., 2019). In the present study, docking results indicated a strong interaction between QUE and RELA. Our study revealed that treatment with Huangqi, QUE and RELA inhibitor helenalin resulted in a considerable decrease in AR symptoms in mice that were exposed to OVA. These treatments also inhibited the expression of proinflammatory cytokines in the nasal mucosa and activated the IFNG/IRF1 axis. The results point towards Huangqi, QUE and RELA inhibition as a potentially effective anti-inflammatory intervention for AR.
Conclusion
Through the use of network pharmacology, we have successfully identified 13 core components and 67 potential targets of Huangqi, which have proven effective in treating AR. The results of molecular docking analysis have revealed that QUE, the primary component of Huangqi used in AR treatment, shows exceptional binding ability to key targets. In vivo experiments have further demonstrated that Huangqi may mitigate the pathological damage associated with AR, while also regulating the production of pro-inflammatory factors and immune response by suppressing the activation of the NF-kB and IFNG/IRF1 pathway. Our study presents a promising new drug for AR, and serves as a comprehensive reference for the mechanistic study of Huangqi and QUE in treating this condition.