Frontal analysis of cell-membrane chromatography for determination of drug-α1D adrenergic receptor affinity

Role of G-protein coupled receptors in cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of death globally, with CVDs accounting for nearly 30% of deaths worldwide each year. G-protein-coupled receptors (GPCRs) are the most prominent family of receptors on the cell surface, and play an essential regulating cellular physiology and pathology. Some GPCR antagonists, such as β-blockers, are standard therapy for the treatment of CVDs. In addition, nearly one-third of the drugs used to treat CVDs target GPCRs. All the evidence demonstrates the crucial role of GPCRs in CVDs. Over the past decades, studies on the structure and function of GPCRs have identified many targets for the treatment of CVDs. In this review, we summarize and discuss the role of GPCRs in the function of the cardiovascular system from both vascular and heart perspectives, then analyze the complex ways in which multiple GPCRs exert regulatory functions in vascular and heart diseases. We hope to provide new ideas for the treatment of CVDs and the development of novel drugs.

Frontal affinity chromatography: An excellent method of analyzing weak biomolecular interactions based on a unique principle

BACKGROUND

Not only strong biomolecular interactions but also weak interactions play important roles in ensuring appropriate operations of many biological systems. Although a thorough investigation of the latter is essential in understanding life science, few suitable research tools are available because of inherent difficulties.

SCOPE OF REVIEW

Frontal affinity chromatography (FAC) is a versatile method that overcomes the inherent difficulties to provide accurate information on weak interactions. Since its concept and merit are not widely recognized, a comprehensive interpretation of FAC is provided in this review to encourage its application among researchers.

MAJOR CONCLUSION

FAC is based on a unique principle of measuring the binding strength by the delayed migration of an analyte through an affinity column. Its utility was elucidated via the lectin-glycan interactions.

GENERAL SIGNIFICANCE

FAC has a great potential as a research tool to solve many difficult problems in general bioscience that are relevant to almost all researchers.

Capture of anti-coagulant active ingredients from Moutan Cortex by platelet immobilized chromatography and evaluation of anticoagulant activity in rats

Moutan Cortex (MC) is a well-known Chinese medicine for promoting blood circulation and relieving blood stasis. The intent of this study was to evaluate the anticoagulant activity of MC and capture the bioactive compounds by platelet immobilized chromatography. Sprague Dawley (SD) rats were randomly divided into the control group, aspirin group and MC group (1.25, 2.5, 5g/kg/d). Coagulation system and platelet activity were investigated to evaluate the anti-coagulation effect of MC. The effective components of MC were captured by platelet immobilized chromatography. High performance liquid chromatography-diode array detection (HPLC-DAD) and liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) analysis were used to identify the binding ingredients. Meanwhile, the efficacy of active ingredients was assessed through inhibiting platelet adhesion and regulating the expression of platelet related proteins. Principal findings showed that 2.5g/kg/d MC significantly prolonged thrombin time (TT) and 5g/kg/d MC significantly prolonged TT and prothrombin time (PT). MC exhibited an inhibitory potency on adenosine diphosphate-induced platelet aggregation. Four active compounds were found by platelet immobilized chromatography including oxypaeoniflorin, tetragalloylglucose, pentagalloyl glucose and benzoylpaeoniflorin; these active ingredients significantly up-regulated the expression of hsp-70 and coronin-1B, reduced the ratio of adhesion platelets. These results suggest that MC markedly promoted blood circulation and relieved blood stasis by inhibiting platelet activation, as an anti-coagulant, elucidating its potential capacity to treat cardiovascular diseases.

Interactions between histamine H1 receptor and its antagonists by using cell membrane chromatography method

Objectives

A high histamine H1 receptor (H1R) expression cell membrane chromatography (CMC) method was developed to investigate the affinity of ligands for H1R.

Methods

The affinity of ligands for H1R was evaluated by frontal analysis. Competition studies and molecular docking study were utilized to study the interactions that occurred at specific binding sites on H1R.

Key findings

The KD values measured by frontal analysis were (8.72 ± 0.21) × 10−7 M for azelastine, (9.12 ± 0.26) × 10−7 M for cyproheptadine, (9.90 ± 0.18) × 10−7 M for doxepin, (1.42 ± 0.13) × 10−6 M for astemizole, (2.25 ± 0.36) × 10−6 M for chlorpheniramine and (3.10 ± 0.27) × 10−6 M for diphenhydramine. The results had a positive correlation with those from radioligand binding assay. The ability of displacement order measured on the binding sites occupied by doxepin was doxepin (KD, (2.95 ± 0.21) × 10−8 M) > astemizole (KD, (5.03 ± 0.18) × 10−7 M) > chlorpheniramine (KD, (1.27 ± 0.16) × 10−6 M) > cyproheptadine (KD, (1.61 ± 0.27) × 10−6 M), whose order met with the scores by molecular docking study.

Conclusions

The studies showed CMC could be applied to investigate drug–receptor interactions.

Comparative normal/failing rat myocardium cell membrane chromatographic analysis system for screening specific components that counteract doxorubicin-induced heart failure from Acontium carmichaeli

Cell membrane chromatography (CMC) derived from pathological tissues is ideal for screening specific components acting on specific diseases from complex medicines owing to the maximum simulation of in vivo drug-receptor interactions. However, there are no pathological tissue-derived CMC models that have ever been developed, as well as no visualized affinity comparison of potential active components between normal and pathological CMC columns. In this study, a novel comparative normal/failing rat myocardium CMC analysis system based on online column selection and comprehensive two-dimensional (2D) chromatography/monolithic column/time-of-flight mass spectrometry was developed for parallel comparison of the chromatographic behaviors on both normal and pathological CMC columns, as well as rapid screening of the specific therapeutic agents that counteract doxorubicin (DOX)-induced heart failure from Acontium carmichaeli (Fuzi). In total, 16 potential active alkaloid components with similar structures in Fuzi were retained on both normal and failing myocardium CMC models. Most of them had obvious decreases of affinities on failing myocardium CMC compared with normal CMC model except for four components, talatizamine (TALA), 14-acetyl-TALA, hetisine, and 14-benzoylneoline. One compound TALA with the highest affinity was isolated for further in vitro pharmacodynamic validation and target identification to validate the screen results. Voltage-dependent K⁺ channel was confirmed as a binding target of TALA and 14-acetyl-TALA with high affinities. The online high throughput comparative CMC analysis method is suitable for screening specific active components from herbal medicines by increasing the specificity of screened results and can also be applied to other biological chromatography models.

Combining human periodontal ligament cell membrane chromatography with online HPLC/MS for screening osteoplastic active compounds from Coptidis Rhizoma

We have developed an online analytical method that combines human periodontal ligament cell membrane chromatography (hPDLC/CMC) with high-performance liquid chromatography and mass spectrometry (LC/MS) for recognizing and identifying osteoplastic active components from Coptidis Rhizoma. Retention fractions on hPDLC/CMC were enriched onto an enrichment column and the components were directly analyzed by combining a 10-port column switcher with an LC/MS system for separation and preliminary identification. Using simvastatin (SIM) as a positive control, berberine from Coptidis Rhizoma was identified as the active component which could act on the hPDLC. The MTT colorimetric assay, alkaline phosphatase (ALP) activity, and staining tests revealed that berberine could promote hPDLC growth, increase the secretion of ALP in the culture medium, and enhance the formation of mineralized nodule, thus it is a potential osteoplastic ingredient. This hPDLC/CMC-online-LC/MS method can be applied for screening active components acting on hPDLC from traditional Chinese medicines exemplified by Coptidis Rhizoma and will be of great utility in drug discovery using natural medicinal herbs as a source of leading compounds.

Using cell membrane chromatography and HPLC-TOF/MS method for in vivo study of active components from roots of Aconitum carmichaeli

An offline two-dimensional system combining a rat cardiac muscle cell membrane chromatography time-of-flight mass spectrometry (CMC-TOF/MS) with a high Performance liquid chromatography time-of-flight mass spectrometry (HPLC-TOF/MS) was established for investigating the parent components and metabolites in rat urine samples after administration of the roots of Aconitum carmichaeli. On the basis ofthe analysis of the first dimension, retention components of the urine sample were collected into 30 fractions (one fraction per minute). Then offline analysis of the second dimension was carried out. 34 compounds including 24 parent alkaloids and 10 potential metabolites were identified from the dosed rat urine, and then binding affinities of different compounds on cell membranes were compared and influences of some functional groups on activity were estimated with the semi-quantification and curve fitting method. As a result, binding affinities decreased along with the process of deacylation, debenzoylation and demethylation, which may be related to the alleviation of toxicity in the procedure of herb processing or metabolism. Moreover, some minor components in rat urine (Songorine, 14-benzoylneoline, Deoxyaconitine, etc.) exerted relatively strong affinity on cell membranes are worth exploring. The results delivered by the System suggest that the CMC can be applied to in vivo study.