Disscousion
Influenza is an acute respiratory infectious disease that threatens human beings, which does great harm to high-risk groups in the epidemic season, so it is of great significance to protect severe influenza high-risk groups and actively treat critical influenza patients. In addition to active immunity, the action mechanism of western medicine has been relatively clear, such as oseltamivir, zanamivir and Arbidol. Traditional Chinese medicine is a cultural treasure of Chinese medicine, which has played an important role in the prevention and treatment of influenza in recent years. However, due to the theory of syndrome differentiation of TCM and human treatment, the treatment of TCM is complicated. With the improvement of the separation and extraction technology of monomer components of TCM, the effective components of TCM are gradually defined, supplemented by the deepening of basic research of TCM and the development of biological information. The application of network pharmacology provides a new method for us to predict the potential targets of the effective components of TCM.
Our study shows that the first five active ingredients of XBCQ are quercetin, luteolin, kaempferol, wogonin and aloe emodin. Among the top five active components of Jingyin granulep [13], four coincide with them, and two overlap with the first five of compound Yizhihao [14], which indirectly shows that the three groups have much in common in antiviral active ingredients. The basic research of its monomer against influenza virus has been verified at the different cell types and animal model.
Quercetin is a kind of polyphenols derived from plants, which has anti-inflammatory, anti-viral and anti-cancer activities [15-17]. Theremore, protein–chemical interactions suggest quercetin as promising drug candidates against COVID-19 as well as other SARS-like viral infections [18]. A strong relationship between quercetin and influenza has been reported in the literature. Wu W found that quercetin a broad-spectrum inhibitor of viral infection, including H1N1, H3N2, H5N1.Quercetin interaction with the HA2 subunit and inhibit the entry of the H5N1 virus, which indicates that quercetin acts as an inhibitory in the early stage of infection [19]. These results corroborate the findings of a great deal of the previous work in quercetin against influenza.
Luteolin is a common flavonoid, ranging from scavenging free radicals, anticancer activity to anti-influenza activity. there study show that luteolin is most effective inhibitor to influenza via establishment and verification of a screening method based on AlphaScreen technique[20].Yan H found that luteolin inhibits the expression of coat protein I complex, which is related to the entry and endocytosis pathway of influenza virus. Its antiviral effect is consistent with previous studies, indicating that the antiviral effect of the effective ingredient of the prescription has a certain theoretical basis [21]. Luteolin inhibited the production of TNF-α and IL-6 in a dose-dependent manner, and shortened the half-life of TNF-α and IL-6mRNA [22]. It has also been reported that luteolin significantly reduced the production of intracellular reactive oxygen species induced by TNF-α in a dose-dependent manner [23]. Luteolin affects the MAPK pathway, which can be demonstrated by the observation of IL-1 β-induced inhibition of cJunN terminal kinase and p38 kinase activation in SW982 cells. Luteolin treatment also inhibited IL-1 β-induced AP-1 nuclear translocation [24]. Luteolin also protects mice from lipopolysaccharide-induced acute lung injury by inhibiting the expression of TNF-α, IL-6, and COX-2. Luteolin down-regulates LPS-induced leukocyte influx into alveolar space [25]. It was found that luteolin attenuated LPS-induced acute lung injury by inhibiting NF-KB and MAPK pathways [26].
In the protein interaction network, the key gene JUN is a transcription factor which is essential for cellular growth and proliferation, across the cell cycle, self-renewal, metabolism and survival processes. Here, Studies have demonstrated that JUN contributes to fibrotic disease not only by increasing activity through pro-fibrotic programs, but also by influencing the host’s overall immune response [27, 28]. Promotes activity of NR5A1 when phosphorylated by HIPK3 would increas steroidogenic gene expression upon cAMP signaling pathway [29]. CASP8 is related to many human diseases. It produces a variety of transcripts and has some non-apoptotic functions, such as regulating the proliferation and differentiation of NK cells and B cells [30]. CASP8 is not only a necessary protease for the exogenous pathway of apoptosis, but also a negative regulator of necrosis [31]. Interleukin-1β (IL-1β) is an important immune cytokine responsible for inflammation, such as influenza or coinfection bacterica. It is related to the severity of infection disease. All patients with H1N1 infection significantly higher levels of IL-1β and IL-6 than lower respiratory tract infections (LRTI), H1N1 virus infection induces significant upregulation of both interleukins IL1β and IL-6 plasma expressions.[32] IL-1β and interleukin-17A (IL-17A) are key mediators of neutrophilic inflammation in influenza-induced chronic lung inflammation. Blocking of IL-17A or IL-1 resulted to a virtual abrogation of neutrophil recruitment in the initial phase of infection. IL-17A and IL-1β are potential targets for treatment of viral exacerbations [33]. Previous studies have demonstrated that NLRP3 inflammasome regulated IL-1β activation during coinfection, which increases the amount of pro-IL-1β substrate for the inflammasome to process [34]. There KEY Targets responses to lipapolysaccharide, molecule of bacterial origin, tumor necrosis factor biological processes. The small-molecule anti-influenza therapeutic durgs be classified four-category currently: primary, neuraminidase inhibitors oseltamivir and zanamivir, which prevent release of nascent virions. Secondary, amantadine and rimantadine, which are M2 ion channel inhibitors. Tertiary, avipirovir and baloxavir, which act on transcription and replication of viral RNA. Quartic, Arbidol has been shown to increase influenza virus HA stability and prevent the low pH-induced HA transition to its fusogenic state. Our study shows that component targets were mainly associated with cytokine receptor binding, cytokine activity, receptor ligand activity, signaling receptor activator in biological processes [35].
The IL-17 family is a subset of cytokines composed of IL-17A-F and plays an important role in both acute and chronic inflammatory responses. Many studies have revealed that delayed clearance of viral load and marked cytokine activation in severe patients of H1N1 virus infection. The IL-17 family signals through its corresponding receptors and activates downstream pathways including NF- κ B, MAPK and C/EBP to induce the expression of antimicrobial peptides, cytokines and chemokines. In the study of H5N1-infected mice, it was found that IL-17 played a protective role in the process of adaptive immunity of ”cytokine storm” and virus clearance [36]. IL-17 has been shown to be protective in severe pandemic influenza, indicating the existence of imbalanced pro-and anti-Th17 responses during this disease [37]. IL-17 deficiency or treatment with monoclonal antibodieswould alleviat acute lung injury induced by the H1N1 virus in mice[38]. In contrast, other groups have showed that IL-17 just played a pathogenic role by recruiting neutrophils to the site of inflammation [39]. IL-17 may act as a ‘double-edged sword’ and contributes to pulmonary immunopathology [40-42]. The TNF-α and NF-κB pathways are central regulators of immune responses, cell survival, and apoptosis, and are modulated by pathogens for their survival. Interference with TNF-α signaling exclusively in distal airway epithelial cells resulted in abrogation of CD8+ mediated lung injury and viral clearance [43, 44].
Molecular docking has been used in drug screening of influenza Neuraminidase Inhibitors [45-48]. Our molecular docking studies based on TCM compounds against known protein targets to treatment influenza. Among the four targets chosen for molecular docking experiments, JUN、CASP8、MAPK1 were reported as key gene in signaling pathway mentioned above. Quercetin, luteolin and naringenin were successful docked to JUN target proteins with a high binding energy. It showed that Quercetin, luteolin and naringenin could bind to JUN, and then inhibited influenza through multi-components, multi-targets and multi-pathways. These findings validate the reliability of the active ingredients screened by network pharmacology and their interaction with influenza targets.