Xing Wang

This study evaluates and compares the protective effects of several type II taste receptor (T2R) agonists against LPS (lipopolysaccharide)-induced inflammatory damage in BEAS-2B cells, focusing on their action via an α-gustducin (encoded by GNAT3)-dependent signaling pathway that leads to NF-κB inhibition. To investigate gene expression, mRNA levels of target inflammatory cytokines and T2R subtypes were quantified by qRT-PCR. Cytotoxicity assessment of LPS and bitter agonists was conducted using the CCK-8 assay. The activation status of the NF-κB pathway was examined by Western blot analysis of total and phosphorylated forms of p65 and IκB. Finally, the specific and essential role of GNAT3 was definitively validated through siRNA-mediated gene knockdown. LPS treatment induced significant upregulation of IL-6 and IL-8 mRNA, along with increased phosphorylation of p65 and IκB in BEAS-2B cells. A direct, parallel comparison of the bitter taste agonists PTC (phenylthiourea), QN (quinine), CPD (carisoprodol), and LK (chloroquine) revealed their capacity to upregulate specific T2R subtypes, suppressing inflammatory mediator release and NF-κB activation. Critically, upon GNAT3 silencing, the inhibitory effects of all tested agonists on p-p65/p65 and p-IκB/IκB ratios were significantly attenuated, without altering total p65 or IκB abundance. This provides direct genetic evidence that GNAT3 is specifically required for mediating the anti-inflammatory effects elicited by these T2R agonists. Multiple bitter receptor agonists exert anti-inflammatory effects on airway epithelial cells in a GNAT3-dependent manner. Our study advances the field by systematically comparing agonist efficacy and establishing the indispensable role of GNAT3 within the anti-inflammatory signaling cascade triggered by T2R agonists, thereby revealing a refined mechanistic insight and potential therapeutic target for inflammatory lung diseases.

Thrombin is a crucial enzyme in the coagulation cascade, and inhibitors of thrombin have been extensively studied as potential antithrombotic agents. The objective of this study was to identify natural inhibitors of thrombin from Panax notoginseng and evaluate their biological activity in vitro and binding characteristics. A combined approach involving molecular docking, thrombin inhibition assays, surface plasmon resonance, and molecular dynamics simulation was utilized to identify natural thrombin inhibitors. The results demonstrated that panaxatriol directly inhibits thrombin, with an IC50 of 10.3 µM. Binding studies using surface plasmon resonance revealed that panaxatriol interacts with thrombin, with a KD value of 7.8 µM. Molecular dynamics analysis indicated that the thrombin-panaxatriol system reached equilibrium rapidly with minimal fluctuations, and the calculated binding free energy was − 23.8 kcal/mol. The interaction between panaxatriol and thrombin involves the amino acid residues Glu146, Glu192, Gly216, Gly219, Tyr60A, and Trp60D. This interaction provides a mechanistic basis for further optimizing panaxatriol as a thrombin inhibitor. Our study has shown that panaxatriol serves as a direct thrombin inhibitor, laying the groundwork for further research and development of novel thrombin inhibitors.

The objective of this study was to identify multiple alkaloids in Coptis chinensis that demonstrate inhibitory activity against DPP-4 and systematically evaluate their activity and binding characteristics. A combined strategy that included molecular docking, a DPP-4 inhibition assay, surface plasmon resonance (SPR), and a molecular dynamics simulation technique was employed. The results showed that nine alkaloids in Coptis chinensis directly inhibited DPP-4, with IC₅₀ values of 3.44–53.73 μM. SPR-based binding studies revealed that these alkaloids display rapid binding and dissociation characteristics when interacting with DPP-4, with K_D values ranging from 8.11 to 29.97 μM. A molecular dynamics analysis revealed that equilibrium was rapidly reached by nine DPP-4–ligand systems with minimal fluctuations, while binding free energy calculations showed that the ∆G_bind values for the nine test compounds ranged from −31.84 to −16.06 kcal/mol. The most important forces for the binding of these alkaloids with DPP-4 are electrostatic interactions and van der Waals forces. Various important amino acid residues, such as Arg125, His126, Phe357, Arg358, and Tyr547, were involved in the inhibition of DPP-4 by the compounds, revealing a mechanistic basis for the further optimization of these alkaloids as DPP-4 inhibitors. This study confirmed nine alkaloids as direct inhibitors of DPP-4 and characterized their binding features, thereby providing a basis for further research and development on novel DPP-4 inhibitors.

Objective. Tinglizi has been extensively used to treat chronic heart failure (CHF) in modern times, but the material basis and pharmacological mechanisms are still unclear. To explore the material basis and corresponding potential targets and to elucidate the mechanism of Tinglizi, network pharmacology and molecular docking methods were utilized. Methods. The main chemical compounds and potential targets of Tinglizi were collected from the pharmacological database analysis platform (TCMSP). The corresponding genes of related action targets were queried through gene cards and UniProt database. The corresponding genes of CHF-related targets were searched through Disgenet database, and the intersection targets were obtained by drawing Venn map with the target genes related to pharmacodynamic components. Then, drug targets and disease targets were intersected and put into STRING database to establish a protein interaction network. The “active ingredient-CHF target” network was constructed with Cytoscape 3.8.2. Finally, Gene Ontology (GO) Enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment of intersection targets were analyzed using metascape. With the aid of SYBYL software, the key active ingredients and core targets were docked at molecular level, and the results were visualized by PyMOL software. Molecular docking was carried out to investigate interactions between active compounds and potential targets. Results. A total of 12 active components in Tinglizi were chosen from the TCMSP database, and 193 corresponding targets were predicted. Twenty-nine potential targets of Tinglizi on CHF were obtained, of which nine were the core targets of this study. Twenty GO items were obtained by GO function enrichment analysis ( ), and 10 signal pathways were screened by KEGG pathway enrichment analysis ( ), which is closely related to the treatment of CHF by Tinglizi. The constructed drug compound composition action target disease network shows that quercetin, kaempferol, and other active compounds play a key role in the whole network. The results of molecular docking showed that all the key active ingredients, such as quercetin and isorhamnetin, were able to successfully dock with ADRB2 and HMOX1 with a total score above 5.0, suggesting that these key components have a strong binding force with the targets. Conclusion. Through network pharmacology and molecular docking technology, we found that the main components of Tinglizi in the treatment of CHF are quercetin, kaempferol, β-sitosterol, isorhamnetin, and so on. The action targets are beta 2-adrenergic receptor (ADRB2), heme oxygenase 1 (HMOX1), and so on. The main pathways are advanced glycation end products/receptor for advanced glycation end products (AGE-RAGE) signaling pathway in diabetic complications, hypoxia-inducible factor (HIF-1) signaling pathway, estrogen signaling pathway, and so on. They play an integrated role in the treatment of CHF.