Surface Plasmon Resonance-Based Membrane Protein-Targeted Active Ingredients Recognition Strategy: Construction and Implementation in Ligand Screening from Herbal Medicines

A dual-target SPR screening system for simultaneous ligand discovery of SARS-CoV-2 spike protein and its receptor ACE2 from Chinese herbs

Traditional Chinese Medicine (TCM) is a supremely valuable resource for the development of drug discovery. Few methods are capable of hunting for potential molecule ligands from TCM towards more than one single protein target. In this study, a novel dual-target surface plasmon resonance (SPR) biosensor was developed to perform targeted compound screening of two key proteins involved in the cellular invasion process of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): the spike (S) protein receptor binding domain (RBD) and the angiotensin-converting enzyme 2 (ACE2). The screening and identification of active compounds from six Chinese herbs were conducted taking into consideration the multi-component and multi-target nature of Traditional Chinese Medicine (TCM). Puerarin from Radix Puerariae Lobatae was discovered to exhibit specific binding affinity to both S protein RBD and ACE2. The results highlight the efficiency of the dual-target SPR system in drug screening and provide a novel approach for exploring the targeted mechanisms of active components from Chinese herbs for disease treatment.

A novel phthalein component ameliorates neuroinflammation and cognitive dysfunction by suppressing the CXCL12/CXCR4 axis in rats with vascular dementia

ETHNOPHARMACOLOGICAL RELEVANCE

Chuanxiong, a plant of the Umbelliferae family, is a genuine medicinal herb from Sichuan Province. Phthalides are one of its main active components and exhibit good protective effect against cerebrovascular diseases. However, the mechanism by which phthalides exert neuroprotective effects is still largely unclear.

AIM OF THE STUDY

In this study, we extracted a phthalein component (named as QBT) from Ligusticum Chuanxiong, and investigated its neuroprotective effects against vascular dementia (VaD) rats and the underlying mechanism, focusing on the chemokine 12 (CXCL12)/chemokine (C-X-C motif) receptor 4 (CXCR4) axis.

METHODS

A rat model of VaD was established, and treated with QBT. Cognitive dysfunction in VaD rats was assessed using the Y-maze, new object recognition, and Morris water maze tests. Neuronal damage and inflammatory response in VaD rats were examined through Nissl staining, immunofluorescence, enzyme-linked immunospecific assay, and western blotting analysis. Furthermore, the effects of QBT on CXCL12/CXCR4 axis and its downstream signaling pathways, Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) and phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/nuclear factor-κB (NF-κB), were investigated in VaD rats and BV2 microglial cells exposed to oxygen glucose deprivation.

RESULTS

QBT significantly alleviated cognitive dysfunction and neuronal damage in VaD rats, along with inhibition of VaD-induced over-activation of microglia and astrocytes and inflammatory response. Moreover, QBT exhibited anti-inflammatory effects by inhibiting the CXCL12/CXCR4 axis and its downstream JAK2/STAT3 and PI3K/AKT/NF-κB pathways, thereby attenuating the neuroinflammatory response both in vivo and in vitro.

CONCLUSION

QBT effectively mitigated neuronal damage and cognitive dysfunction in VaD rats, exerting neuroprotective effects by suppressing neuroinflammatory response through inhibition of the CXCL12/CXCR4 axis.

Spirohypertones A and B as potent antipsoriatics: Tumor necrosis factor-α inhibitors with unprecedented chemical architectures

Tumor necrosis factor-α (TNF-α) is a promising target for inflammatory and autoimmune diseases. Spirohypertones A (1) and B (2), two unprecedented polycyclic polyprenylated acylphloroglucinols with highly rearranged skeletons, were isolated from Hypericum patulum. The structures of 1 and 2 were confirmed through comprehensive spectroscopic analysis, single-crystal X-ray diffraction and electronic circular dichroism calculations. Importantly, 2 showed remarkable TNF-α inhibitory activity, which could protect L929 cells from death induced by co-incubation with TNF-α and actinomycin D. It also demonstrated the ability to suppress the inflammatory response in HaCaT cells stimulated with TNF-α. Notably, in an imiquimod-induced psoriasis murine model, 2 restrained symptoms of epidermal hyperplasia associated with psoriasis, presenting anti-inflammatory and antiproliferative effects. This discovery positions 2 as a potent TNF-α inhibitor, providing a promising lead compound for developing an antipsoriatic agent.

A chromatographic method for determining the interaction between a drug and two target proteins by fabricating a dual-heterogeneous surface

Characterization of the drug-target interactions is pivotal throughout the whole procedure of drug development. Most of the current assays, particularly, chromatographic methods lack the capacity to reveal drug adsorption on the muti-target surface. To this end, we derived a reliable and workable mathematical equation for revealing drug bindings to dual targets on the heterogeneous surface starting from the mass balance equation. The derivatization relied on the correlation of drug injection amounts with their retention factors. Experimental validation was performed by determining the binding parameters of three canonical drugs on a heterogeneous surface, which was fabricated by fusing angiotensin receptor type I and type II receptors (AT1R and AT2R) at the terminuses of circularly permuted HaloTag (cpHaloTag) and immobilizing the whole fusion protein onto 6-bromohexanoic acid modified silica gel. We proved that immobilized AT1R-cpHalo-AT2R maintained the original ligand- and antibody-binding activities of the two receptors in three weeks. The association constants of valsartan, candesartan, and telmisartan to AT1R were (6.26±0.14) × 105, (9.66±0.71) × 105, and (3.17±0.03) × 105 L/mol. In the same column, their association constants to AT2R were (1.25±0.04) × 104, (2.30±0.08) × 104, and (8.51±0.06) × 103 L/mol. The patterns of the association constants to AT1R/AT2R (candesartan>valsartan>telmisartan) were in good line with the data by performing nonlinear chromatography on control columns containing immobilized AT1R or AT2R alone. This provided proof of the fact that the derivatization allowed the determination of drug bindings on the heterogeneous surface with the utilization of a single series of injections and linear regression. We reasoned that is simple enough to model the bindings of drug adsorption on commercially available adsorbents in fundamental or industrial fields, thus having the potential to become a universal method for analyzing the bindings of a drug to the heterogeneous surface containing multiple targets.

Chemokine Receptor Antagonists Prevent and Reverse Cofilin-Actin Rod Pathology and Protect Synapses in Cultured Rodent and Human iPSC-Derived Neurons

Synapse loss is the principal cause of cognitive decline in Alzheimer's disease (AD) and related disorders (ADRD). Synapse development depends on the intricate dynamics of the neuronal cytoskeleton. Cofilin, the major protein regulating actin dynamics, can be sequestered into cofilactin rods, intra-neurite bundles of cofilin-saturated actin filaments that can disrupt vesicular trafficking and cause synaptic loss. Rods are a brain pathology in human AD and mouse models of AD and ADRD. Eliminating rods is the focus of this paper. One pathway for rod formation is triggered in ~20% of rodent hippocampal neurons by disease-related factors (e.g., soluble oligomers of Amyloid-β (Aβ)) and requires cellular prion protein (PrPC), active NADPH oxidase (NOX), and cytokine/chemokine receptors (CCRs). FDA-approved antagonists of CXCR4 and CCR5 inhibit Aβ-induced rods in both rodent and human neurons with effective concentrations for 50% rod reduction (EC50) of 1-10 nM. Remarkably, two D-amino acid receptor-active peptides (RAP-103 and RAP-310) inhibit Aβ-induced rods with an EC50 of ~1 pM in mouse neurons and ~0.1 pM in human neurons. These peptides are analogs of D-Ala-Peptide T-Amide (DAPTA) and share a pentapeptide sequence (TTNYT) antagonistic to several CCR-dependent responses. RAP-103 does not inhibit neuritogenesis or outgrowth even at 1 µM, >106-fold above its EC50. N-terminal methylation, or D-Thr to D-Ser substitution, decreases the rod-inhibiting potency of RAP-103 by 103-fold, suggesting high target specificity. Neither RAP peptide inhibits neuronal rod formation induced by excitotoxic glutamate, but both inhibit rods induced in human neurons by several PrPC/NOX pathway activators (Aβ, HIV-gp120 protein, and IL-6). Significantly, RAP-103 completely protects against Aβ-induced loss of mature and developing synapses and, at 0.1 nM, reverses rods in both rodent and human neurons (T½ ~ 3 h) even in the continuous presence of Aβ. Thus, this orally available, brain-permeable peptide should be highly effective in reducing rod pathology in multifactorial neurological diseases with mixed proteinopathies acting through PrPC/NOX.

Functional annotation map of natural compounds in traditional Chinese medicines library: TCMs with myocardial protection as a case

The chemical complexity of traditional Chinese medicines (TCMs) makes the active and functional annotation of natural compounds challenging. Herein, we developed the TCMs-Compounds Functional Annotation platform (TCMs-CFA) for large-scale predicting active compounds with potential mechanisms from TCM complex system, without isolating and activity testing every single compound one by one. The platform was established based on the integration of TCMs knowledge base, chemome profiling, and high-content imaging. It mainly included: (1) selection of herbal drugs of target based on TCMs knowledge base; (2) chemome profiling of TCMs extract library by LC‒MS; (3) cytological profiling of TCMs extract library by high-content cell-based imaging; (4) active compounds discovery by combining each mass signal and multi-parametric cell phenotypes; (5) construction of functional annotation map for predicting the potential mechanisms of lead compounds. In this stud TCMs with myocardial protection were applied as a case study, and validated for the feasibility and utility of the platform. Seven frequently used herbal drugs (Ginseng, etc.) were screened from 100,000 TCMs formulas for myocardial protection and subsequently prepared as a library of 700 extracts. By using TCMs-CFA platform, 81 lead compounds, including 10 novel bioactive ones, were quickly identified by correlating 8089 mass signals with 170,100 cytological parameters from an extract library. The TCMs-CFA platform described a new evidence-led tool for the rapid discovery process by data mining strategies, which is valuable for novel lead compounds from TCMs. All computations are done through Python and are publicly available on GitHub.

Senkyunolide I: A Review of Its Phytochemistry, Pharmacology, Pharmacokinetics, and Drug-Likeness

Senkyunolide I (SI) is a natural phthalide that has drawn increasing interest for its potential as a cardio-cerebral vascular drug candidate. In this paper, the botanical sources, phytochemical characteristics, chemical and biological transformations, pharmacological and pharmacokinetic properties, and drug-likeness of SI are reviewed through a comprehensive literature survey, in order to provide support for its further research and applications. In general, SI is mainly distributed in Umbelliferae plants, and it is relatively stable to heat, acid, and oxygen, with good blood-brain barrier (BBB) permeability. Substantial studies have established reliable methods for the isolation, purification, and content determination of SI. Its pharmacological effects include analgesic, anti-inflammatory, antioxidant, anti-thrombotic, anti-tumor effects, alleviating ischemia-reperfusion injury, etc. Pharmacokinetic parameters indicate that its metabolic pathway is mainly phase Ⅱ metabolism, and it is rapidly absorbed in vivo and widely distributed in the kidneys, liver, and lungs.

Antiviral Potential of Plants against COVID-19 during Outbreaks-An Update

Several human diseases are caused by viruses, including cancer, Type I diabetes, Alzheimer's disease, and hepatocellular carcinoma. In the past, people have suffered greatly from viral diseases such as polio, mumps, measles, dengue fever, SARS, MERS, AIDS, chikungunya fever, encephalitis, and influenza. Recently, COVID-19 has become a pandemic in most parts of the world. Although vaccines are available to fight the infection, their safety and clinical trial data are still questionable. Social distancing, isolation, the use of sanitizer, and personal productive strategies have been implemented to prevent the spread of the virus. Moreover, the search for a potential therapeutic molecule is ongoing. Based on experiences with outbreaks of SARS and MERS, many research studies reveal the potential of medicinal herbs/plants or chemical compounds extracted from them to counteract the effects of these viral diseases. COVID-19's current status includes a decrease in infection rates as a result of large-scale vaccination program implementation by several countries. But it is still very close and needs to boost people's natural immunity in a cost-effective way through phytomedicines because many underdeveloped countries do not have their own vaccination facilities. In this article, phytomedicines as plant parts or plant-derived metabolites that can affect the entry of a virus or its infectiousness inside hosts are described. Finally, it is concluded that the therapeutic potential of medicinal plants must be analyzed and evaluated entirely in the control of COVID-19 in cases of uncontrollable SARS infection.

Chitosan-based matrix solid-phase dispersion extraction assisted cell membrane magnetic bead ligand-affinity assay for screening active compounds from Fructus Cnidii

Cell membrane ligand-affinity assay is a useful tool for screening the active compounds from natural products. However, in traditional cell membrane ligand-affinity assays, natural products need to be refluxed, before being analyzed. This process consumes considerable time and energy and cannot be used for screening natural products that contain thermally unstable compounds. Therefore, an efficient analytical method is required. In this study, chitosan-based matrix solid-phase dispersion extraction was combined with cell membrane magnetic bead ligand-affinity assay to form a novel method for identifying the active compounds in Fructus Cnidii such as osthole and imperatorin. When compared with traditional cell membrane ligand-affinity assays, this assay requires less energy, extraction time (7 min), solvent volume (1.2 mL) and fewer natural products (40 mg). This indicates that the chitosan-based matrix solid-phase dispersion extraction assisted cell membrane magnetic beads ligand-affinity assay is an alternative analytical method for studying natural products. This article is protected by copyright. All rights reserved.

A Supported Lipid Bilayer-Based Lab-on-a-Chip Biosensor for the Rapid Electrical Screening of Coronavirus Drugs

With the rapid spread and multigeneration variation of coronavirus, rapid drug development has become imperative. A major obstacle to addressing this issue is adequately constructing the cell membrane at the molecular level, which enables in vitro observation of the cell response to virus and drug molecules quantitatively, shortening the drug experiment cycle. Herein, we propose a rapid and label-free supported lipid bilayer-based lab-on-a-chip biosensor for the screening of effective inhibition drugs. An extended gate electrode was prepared and functionalized by an angiotensin-converting enzyme II (ACE2) receptor-incorporated supported lipid bilayer (SLB). Such an integrated system can convert the interactions of targets and membrane receptors into real-time charge signals. The platform can simulate the cell membrane microenvironment in vitro and accurately capture the interaction signal between the target and the cell membrane with minimized interference, thus observing the drug action pathway quantitatively and realizing drug screening effectively. Due to these label-free, low-cost, convenient, and integrated advantages, it is a suitable candidate method for the rapid drug screening for the early treatment and prevention of worldwide spread of coronavirus.

A strategy of screening and binding analysis of bioactive components from traditional Chinese medicine based on surface plasmon resonance biosensor

Elucidating the active components of traditional Chinese medicine (TCM) is essential for understanding the mechanisms of TCM and promote its rational use as well as TCM-derived drug development. Recent studies have shown that surface plasmon resonance (SPR) technology is promising in this field. In the present study, we propose an SPR-based integrated strategy to screen and analyze the major active components of TCM. We used Radix Paeoniae Alba (RPA) as an example to identify the compounds that can account for its anti-inflammatory mechanism via tumor necrosis factor receptor type 1 (TNF-R1). First, RPA extraction was analyzed using an SPR-based screening system, and the potential active ingredients were collected, enriched, and identified as paeoniflorin and paeonol. Next, the affinity constants of paeoniflorin and paeonol were determined as 4.9 and 11.8 μM, respectively. Then, SPR-based competition assays and molecular docking were performed to show that the two compounds could compete with tumor necrosis factor-α (TNF-α) while binding to the subdomain 1 site of TNF-R1. Finally, in biological assays, the two compounds suppressed cytotoxicity and apoptosis induced by TNF-α in the L929 cell line. These findings prove that SPR technology is a useful tool for determining the active ingredients of TCM at the molecular level and can be used in various aspects of drug development. The SPR-based integrated strategy is reliable and feasible in TCM studies and will shed light on the elucidation of the pharmacological mechanism of TCM and facilitate its modernization.

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A surface plasmon resonance-based integrated strategy was established to analyze traditional Chinese medicine.

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Surface plasmon resonance technology can be used for ligand screening, affinity detection, and binding site confirmation.

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Paeoniflorin and paeonol were identified as TNF-R1-bound ingredients in RPA.

Tailored Biosensors for Drug Screening, Efficacy Assessment, and Toxicity Evaluation

Biosensors have been flourishing in the field of drug discovery with pronounced developments in the past few years. They facilitate the screening and discovery of innovative drugs. However, there is still a lack of critical reviews that compare the merits and shortcomings of these biosensors from a pharmaceutical point of view. This contribution presents a critical and up-to-date overview on the recent progress of tailored biosensors, including surface plasmon resonance, fluorescent, photoelectrochemical, and electrochemical systems with emphasis on their mechanisms and applications in drug screening, efficacy assessment, and toxicity evaluation. Multiple functional nanomaterials have also been incorporated into the biosensors. Representative examples of each type of biosensors are discussed in terms of design strategy, response mechanism, and potential applications. In the end, we also compare the results and summarize the major insights gained from the works, demonstrating the challenges and prospects of biosensors-assisted drug discovery.

An integrative strategy for discovery of functional compound combination from Traditional Chinese Medicine: Danhong Injection as a model

Traditional Chinese Medicine formulas, which are usually considered exerting their holistic clinical benefits via multi-component, multi-target manner, are unique resources for the discovery of multi-component drug combinations. In order to screen and optimize the functional compound combination (FCC) from TCM, we established a novel four-step 'GCIC' strategy, including 'Global profiling', 'Chemical structural classification', 'Intra-group screening' and 'Component-knockout optimization'. Following this strategy, an FCC consisted of four components from Danhong Injection (DHI) was identified, containing ferulic acid, cryptotanshinone, quercetin and anhydrosafflor yellow B. The holistic neuroprotective effects of the FCC were further investigated, indicating that the combination can both activate the antioxidative and anti-inflammatory responses in PC12 cells to protect them from oxidative stress. Major signaling pathways as Nrf2/ARE and Nrf2/AMPK/GSK3β were involved in the protective process of FCC. The 'GCIC' strategy established in this study might provide an alternation to traditional strategies in discovering the bioactive components from herbal medicines, especially compounded TCM formulas.

Layer-by-layer assembly strategy for fabrication of polydopamine-polyethyleneimine hybrid modified fibers and their application to solid-phase microextraction of bioactive molecules from medicinal plant samples followed by surface plasmon resonance biosensor validation

A solid-phase microextraction method is introduced to overcome limitations of classical phytochemical pattern of identifying bioactive compounds, including tedious and time-consuming separation and purification step and consumption of large amounts of organic solvents, which was non-environmentally- friendly. In this proposed method for solid-phase microextraction, polyvinylidene fluoride fibers@polydopamine@polyethyleneimine@receptor as a solid part of the extractors were pushed into sample solution of medicinal plants, and the procedure was followed by stirring and easily dissociation of receptor binding ligands in organic solvent through pulling out of the functionalized fibers. Xanthine oxidase was chosen as the model receptor, while isoacteoside was selected as the model inhibitor. Several effecting parameters were optimized by experimental design, including temperature, ion strength and pH. Nine bioactive components were obtained from extract of Plantago depressa by using the established solid-phase micro-extraction method. The limit of detection and limit of quantification of the nine components ranged from 0.0008 to 0.03 mg mL^-1 and from 0.001 to 0.016 mg mL^-1, respectively. The RSD values of intra-day and inter-day precisions ranged from 0.24% to 2.19% and 0.62%-2.84%, respectively. The average recoveries of the nine components were from 95.06 to 104.03% with relative standard deviation (RSD) values from 1.02 to 2.90% for Plantago depressa. The RSD values of stability of the nine components ranged from 1.36% to 2.74%, which satisfied the requirements of an analytical method. In addition, surface plasmon resonance biosensor was utilized to corroborate the binding affinity between these compounds and receptor. The avidity values of these ligands corresponded well with their IC₅₀ values. The results confirmed that polydopamine and polyethyleneimine hybrid modified polyvinylidene fluoride fibers based solid-phase microextraction method was successfully utilized for locating bioactive compounds of medicinal plants.

The acaricidal mechanism and active compounds against Psoroptes cuniculi of the methanol extract of Adonis coerulea Maxim II: Integrated proteomics and SPR analysis

Adonis coerulea Maxim. as a folk medicine, presented acaricidal acitvity. However, the mode of action and active compounds were unclear. In this study, using proteomics and surface plasmon resonance (SPR) technology the mode of action and active compounds of A. coerulea were investigated, as well as a sensitive and environmentally friendly analytical method developed. Proteomics analysis results showed that after treatment of mites with A. coerulea methanol extract (MEAC), 135 proteins were differentially expressed, most of them enriched in the myocardium pathway and participated in the function of the inflated cystic organ. Na+-K+-ATPase may be a potential target. Then, it was used as a target to capture the compounds from the extract using a SPR test. Twelve compounds were found, five compounds, namely ellagic acid, ouabain, convallatoxin, strophanthidin and cymarin presented the higher affinity with Na+-K+-ATPase in molecular docking test. Further study showed that the latter four compounds presented the stronger cytotoxicity and the inhibitory effect on Na+-K+-ATPase with IC50 values ranging with 2.38-0.56 μg/mL, and also showed toxicity against Psoroptes cuniculi. These results indicated that MEAC presented toxicity against mites by inhibiting Na+-K+-ATPase, and cardiac glycosides may be active compounds of this plant in terms of its acaricidal activity. Only 10 g of plant was used to investigate its active compounds. This study lays the foundation for developing sensitive methods for active compound detection.

The active compounds and AChE inhibitor of the methanol extract of Adonis coerulea maxim against Psoroptes cuniculi

Adonis coerulea Maxim. presents acaricidal activity in vitro and in vivo, and inhibits AChE and other enzymes activities. However, the active compounds against Psoroptes cuniculi were still unclear. AChE, a common acaricidal and insecticidal target, plays a key role in neural conduction of mites. In this study, using surface plasmon resonance (SPR) technology, AChE was used as a target to capture the compounds from A. coerulea methanol extract (MEAC). After calculating the affinity with molecular docking, the inhibitory effect of compounds against AChE was studied. Results showed that 27 compounds were captured by AChE and identified from MEAC by LC-MS/MS. Among of these compounds, eight compounds presented the high affinity with AChE and high scores in molecular docking assay, especially for silibinin (-12.19 kcal/mol) and vitexin (-11.72 kcal/mol). Further studies showed that although these compounds have the weak cytotoxicity against C6/36 cells, silibinin, quercetin and corilagin could inhibit AChE activity with IC₅₀ values of 40.11 μg/mL, 46.15 μg/mL and 50.98 μg/mL, respectively. These results indicated that silibinin, quercetin and corilagin may be responsible for AChE inhibition which contributes to the acaricidal properties of A coerulea. This study lays the foundation for developing sensitive and sustainability methods for active compound detection from plants.