Rapid screening of bioactive compound in Sanzi Yangqin Decoction and investigating of binding mechanism by immobilized β2-adrenogic receptor chromatography coupled with molecular docking

Revealing the anti-inflammatory ingredients in wine-processed Radix et Rhizoma Rhei using immobilized cysteinyl leukotriene receptor type 1 as the stationary phase

Despite the tremendous progress of wine-processed Radix et Rhizoma Rhei (Jiudahuang, JDH) in removing toxic heat from the blood in the upper portion of the body for hundreds of years, the deep understanding of its functional material basis of the anti-inflammatory ingredients remains unclear due to the lack of high specific and efficient methods. Herein, taking Cysteinyl leukotriene receptor type 1(CysLT1R) as the target protein, we established a chromatographic method based on the immobilized CysLT1R using haloalkane dehalogenases (Halo) at the C-terminus of the receptor in one step. After careful characterization by X-ray photoelectronic spectroscopy, immune-fluorometric analysis, and chromatographic investigations, the immobilized receptor was used to screen the anti-inflammatory ingredients in JDH. Aloe-emodin, rhein, emodin, chrysophanol, and physcion were identified as the main anthraquinone exerting anti-inflammatory effects in the drug. The association constants for the five compounds to bind with the receptor were calculated as (0.30 ± 0.06)× 105, (0.35 ± 0.03)× 105, (0.46 ± 0.05)× 105, (1.05 ± 0.14)× 105, and (1.66 ± 0.17)× 105 M-1 by injection amount-dependent method. Meanwhile, hydrogen bonds were identified as the main driving force for the five compounds to bind with CysLT1R by molecular docking. Based on these results, we believe that the immobilized receptor chromatography preserves historic significance in revealing the functional material basis of the complex matrices.

The mechanism of Sanzi Yangqin decoction for asthma treatment based on network pharmacology and experimental verification

BACKGROUND

Asthma is a chronic airway inflammatory disease characterized by airway inflammation, mucus hypersecretion, airway hyper-reactivity. Sanzi Yangqin Decoction (SZYQD) is widely prescribed for asthma treatment. Its anti-asthma activities have been reported in animal model, but the exact mechanism and targets of SZYQD in asthma treatment have not been fully elucidated.

METHODS

A network pharmacological approach was used to predict the active components, targets, and signalling pathways of SZYQD in asthma, including potential target prediction, protein‒protein interaction (PPI) network construction and analysis, and Gene Ont (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The active ingredients were identified from the SZYQD, and were molecular docked according to the results of network pharmacology. A mouse model of asthma induced by ovalbumin (OVA) and lipopolysaccharide (LPS) was constructed to evaluate the therapeutic effect of SZYQD. Furthermore, the effects of SZYQD and its active ingredients were tested in vitro for regulating inflammation and MUC5AC expression (two main pathophysiologic abnormalities of asthma) in macrophages and airway epithelial cells by using Real-time PCR and western blotting.

RESULTS

A total of 28 active ingredients and 111 HUB genes were screened in the relevant databases, including three key ingredients (luteolin, β-carotene, and Sinapine) and nine core target genes (JUN, CTNNB1, IL10, TP53, AKT1, STAT3, TNF, IL6 and EGFR). KEGG and GO analysis indicated that the potential anti-asthmatic mechanisms of SZYQD were related to PI3K-Akt signalling pathway and response to lipopolysaccharide, etc. In the in vivo asthmatic model, our findings demonstrated that SZYQD exerted a protective effect against asthmatic mice induced by OVA and LPS through the inhibition of inflammation and mucus overproduction. Consistently, cell experiments showed that the SZYQD extract or the key active ingredients luteolin significantly decreased lipopolysaccharide (LPS)-induced IL-6 expression and activation of the NF-κB pathway in macrophages. In addition, SZYQD extract or luteolin inhibited activation of the AKT pathway and expression of MUC5AC induced by EGF in airway epithelial cells.

CONCLUSION

The anti-asthmatic mechanism of SZYQD might be associated with inhibiting inflammation and airway mucus hypersecretion by regulating the NF-κB and AKT signalling pathways as predicted by network pharmacology, which provides more evidence for the application of SZYQD in asthma treatment.

Discovery of anti-allergic components in Guomingkang Formula using sensitive HEMT biochips coupled with in vitro and in vivo validation

BACKGROUND

Allergic rhinitis (AR) is a prevalent allergic disease, which seriously affects the sufferers' life quality and increases the socioeconomic burden. Guominkang (GMK), a well-known prescription for AR treatment, showed satisfactory effects; while its anti-allergic components remain to be disclosed. AlGaN/GaN HEMT biochip is more sensitive and cost-effective than other binding equipments, indicating its great potential for screening of active ingredients from herbal medicines.

METHODS

AR mouse models were first established to test the anti-allergic effect of GMK and discover the ingredients absorbed into blood by ultra-high performance liquid chromatography-mass spectra (UHPLC-MS). Then, novel Syk/Lyn/Fyn-functionalized high electron mobility transistor (HEMT) biochips with high sensitivity and specificity were constructed and applied to screen the active components. Finally, the results from HEMT biochips screening were validated via in silico (molecular docking and molecular dynamics simulation), in vitro (RBL-2H3 cells), and in vivo (PCA mice model) assays.

RESULTS

GMK showed a potent therapeutic effect on AR mice, and fifteen components were identified from the medicated plasma. Furthermore, hamaudol was firstly found to selectively inhibit the Syk and Lyn, and emodin was to selectively inhibit Lyn, which were further confirmed by isothermal titration calorimetry, molecular docking, and molecular dynamics simulation analyses. Suppression of the activation of FcεRI-MAPK signals might be the possible mechanism of the anti-allergic effect of hamaudol.

CONCLUSIONS

The targets of emodin and hamaudol were discovered by HEMT biochips for the first time. This study provided a novel and effective strategy to discover active components in a complex herbal formula by using AlGaN/GaN HEMT biochips.

Advances in receptor chromatography for drug discovery and drug-receptor interaction studies

Receptor chromatography involves high-throughput separation and accurate drug screening based on specific drug-receptor recognition and affinity, which has been widely used to screen active compounds in complex samples. This review summarizes the immobilization methods for receptors from three aspects: random covalent immobilization methods, site-specific covalent immobilization methods and dual-target receptor chromatography. Meanwhile, it focuses on its applications from three angles: screening active compounds in natural products, in natural-product-derived DNA-encoded compound libraries and drug-receptor interactions. This review provides new insights for the design and application of receptor chromatography, high-throughput and accurate drug screening, drug-receptor interactions and more. Teaser: This review summarizes the immobilization methods of receptors and the application of receptor chromatography, which will provide new insights for the design and application of receptor chromatography, rapid drug screening, drug-receptor interactions and more.

Protein superglue inspired in-situ one-step site-specific immobilization of beta2-adrenoceptor and its application in bioactive compound screening from Cortex Magnoliae Officinalis

The platforms based on immobilization of transmembrane proteins have become an effective way to study drug-protein interaction and identify new leads for drug discovery. Herein, we exploited the protein superglue (i.e. SpyTag-SpyCatcher chemistry) for site-specific, oriented, and in-situ one-step beta2-adrenoceptor (β₂-AR) immobilization. SpyCatcher was used as a fusion tag at the C-terminal of β₂-AR and the macroporous silica gels were functionalized with the SpyTag peptide. Immobilization was realized by immersing the gels into the E.coli cell lysate containing β₂-AR-SpyCatcher. Characterization of the functionalized gels was performed by X-ray photoelectron spectroscopy and fluorescence microscopy. Adsorption energy distribution calculation, injection amount dependent analysis (IADA) and nonlinear chromatographic were used for receptor-ligand interaction analysis. The affinity rank order of four ligands to the receptor was tulobuterol> chlorprenaline> salbutamol> terbutaline, which showed highly consistent with data from the radioligand binding assay and the β₂-AR column prepared by HaloTag technology. Magnolol and honokiol were screened from Cortex Magnoliae Officinalis and proved to promote the expression of the receptor in human airway smooth muscle cells. Our work unraveled the great potential to generate good bioactivity of the immobilized β₂-AR through Spy toolbox. This technology can be extended to the immobilization of other functional proteins, providing a better alternative in the field of bioanalysis, biosensing, and separation science.

Early potential evaluation of lead compounds from a DNA-encoded library by the determination of their thermodynamics through a chromatographic method based on immobilized β2-adrenoceptor

Early potential evaluation of lead compounds is critical to decrease downstream lead-optimization cycle times and clinical attrition rates for drug development. This increasingly necessitates the methodologies for accurately evaluating the potential compounds. This work immobilized β₂-adrenoceptor (β₂-AR) onto microspheres through Halo-tag mediated reaction. Characterizing the resulting microspheres by elemental and functional analysis, we utilized the immobilized receptor to determine the thermodynamics of terbutaline, tulobuterol, clorprenaline, salbutamol, and methoxyphenamine. The association constants correlated to their capacity factors on the column containing the immobilized β₂-AR, thus providing a possibility for early potential evaluation of lead compounds from complex matrices like a DNA-encoded library. By this model, the lead compound (XC267) was predicted to have an association constant higher than terbutaline, salbutamol, and methoxyphenamine, but lower than tulobuterol and clorprenaline. The binding interaction between XC267 and β₂-AR is a spontaneous endothermic process with an association constant of (6.62 ± 0.13) × 10⁴ M^-1 at 37 °C. The change of Gibbs free energy(ΔG^θ), enthalpy change (ΔH^θ), and entropy change (ΔS^θ) was -28.49 kJ/mol, -10.58 kJ/mol, and 57.79 J/moL·K at 37 °C. By the semi-empirical rule of Ross, the driving force of the interaction between XC267 and β₂-AR was electrostatic interaction. Such binding force was also achieved by molecular docking. These results suggested that XC267 is a candidate to treat asthma by specific binding to β₂-AR. We reasoned that receptor chromatography is able to the early potential evaluation of lead compounds from complex matrices.

Screening the bioactive compound from Coptis chinensis inflorescence by immobilized Peroxisome proliferator activated receptor gamma

Coptis chinensis inflorescence is a by-product of Coptis chinensis Franch and riches in alkaloids. We screened the bioactive compounds in the by-product through an immobilized peroxisome proliferator-activated receptor gamma. The receptor was covalently immobilized on the macroporous silica gel through amino groups to generate the affinity stationary phase and was applied for screening. Berberine, palmatine, and jatrorrhizine were identified as the retained components of the herb on the affinity column. We evaluated the binding of the three bioactive compounds with the receptor by nonlinear chromatography and molecular docking. The affinities of the compounds to the receptor were (1.42±0.10) ×10⁸ M^-1 , (4.88±0.38) ×10⁷ M^-1 , and (1.65±0.13) ×10⁷ M^-1 for berberine, palmatine, and jatrorrhizine, with dissociation rate constants of (17.70±0.03) ×10^-3 S^-1 , (5.18±0.25) ×10^-2 S^-1 , and (15.7±0.05) ×10^-2 S^-1 , respectively. Cys285, Arg288, Ile326, Leu330, and His449 in the agonist binding pocket of the receptor participated in the formation of bioactive compound-receptor conjugates. These data indicated that the immobilized receptor is a reliable alternative for screening the bioactive compounds. In addition, Coptis chinensis inflorescence has the potential to be a source for drug discovery. This article is protected by copyright. All rights reserved.

Metabolic profiling and pharmacokinetic studies of sinapine thiocyanate by UHPLC-Q/TOF-MS and UHPLC-MS/MS

Sinapine thiocyanate (ST) is an index component and pharmacological active component of Semen Sinapis and Semen Raphani, and it is widely used to relieving cough and asthma. This study aimed to obtain the metabolic and pharmacokinetic characterization of ST. The metabolic profiles of ST were obtained from rat plasma, urine, and feces via ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UHPLC-Q/TOF-MS). Thirteen metabolites were structurally identified, and the proposed metabolic pathways of ST included deamination, demethylation, hydrogenation, dehydration, and extensive conjugation, including glucuronidation and sulfonation. ST was selected as the plasma marker for the pharmacokinetic study. A simple and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the quantitation of ST in rat plasma. The linear range of ST was 0.1-500 ng/mL (R² = 0.9976), and the lowest limit of quantification was 0.1 ng/mL. The intra-precision and inter-precision of the assay were 1.31-5.12% and 2.72-7.66%, and the accuracy (RE%) ranged from - 4.88% to 3.82% and - 3.47% to 6.18%. The extraction recovery, matrix effect, and stability of ST were within acceptable limits. The established method was validated and successfully applied to the pharmacokinetic study of ST. For pharmacokinetic experiments, the male Sprague-Dawley rats were administrated with ST solution intravenously (2 mg/kg) or orally (100 mg/kg). The oral absolute bioavailability of ST was calculated as 1.84%, and the apparent volume of distribution of intravenous and intragastric administrations were 107.51 ± 21.16 L/kg and 78.60 ± 14.44 L/kg, respectively. The maximum plasma concentration was 47.82 ± 18.77 nM, and the time to maximum peak was 88.74 ± 20.08 min for the intragastric dosing group. According to the pharmacokinetic and metabolic profiling results, metabolites with high abundance of ST in bio-fluids would be the next object in tissue distribution and pharmacodynamic study.