Construction and application of H1R ligand screening materials based on SMA stabilization and his-tag covalent immobilization of membrane proteins

The histamine H1 receptor (H1R) plays a pivotal role in allergy initiation and undergoes the necessity of devising a high-throughput screening approach centered on H1R to screen novel ligands effectively. This study suggests a method employing styrene maleic acid (SMA) extraction and His-tag covalent bonding to immobilize H1R membrane proteins, minimizing the interference of nonspecific proteins interference while preserving native protein structure and maximizing target exposure. This approach was utilized to develop a novel material for high-throughput ligand screening and implemented in cell membrane chromatography (CMC). An H1R-His-SMALPs/CMC model was established and its chromatographic performance (selectivity, specificity and lifespan) validated, demonstrating a significant enhancement in lifespan compared to previous CMC models. Subsequently, this model facilitated high-throughput screening of H1R ligands in the compound library and preliminary activity verification of potential H1R antagonists. Identification of a novel H1R antagonist laid the foundation for further development in this area.

Mast cell degranulation and bradykinin-induced angioedema - searching for the missing link

Initiation of the bradykinin generation cascade is responsible for the occurrence of attacks in some types of angioedema without wheals. Hereditary angioedema due to C1 inhibitor deficiency (HAE-C1-INH) is one such clinical entity. In this paper, we explore the existing evidence that mast cells (MCs) degranulation may contribute to the activation of the kallikrein-kinin system cascade, followed by bradykinin formation and angioedema. We present the multidirectional effects of MC-derived heparin and other polyanions on the major components of the kinin-kallikrein system, particularly on the factor XII activation. Although, bradykinin- and histamine-mediated symptoms are distinct clinical phenomena, they share some common features, such as some similar triggers and a predilection to occur at sites where mast cells reside, namely the skin and mucous membranes. In addition, recent observations indicate a high incidence of hypersensitivity reactions associated with MC degranulation in the HAE-C1-INH patient population. However, not all of these can be explained by IgE-dependent mechanisms. Mast cell-related G protein-coupled receptor-X2 (MRGPRX2), which has recently attracted scientific interest, may be involved in the activation of MCs through a different pathway. Therefore, we reviewed MRGPRX2 ligands that HAE-C1-INH patients may be exposed to in their daily lives and that may affect MCs degranulation. We also discussed the known inter- and intra-individual variability in the course of HAE-C1-INH in relation to factors responsible for possible variability in the strength of the response to MRGPRX2 receptor stimulation. The above issues raise several questions for future research. It is not known to what extent a prophylactic or therapeutic intervention targeting the pathways of one mechanism (mast cell degranulation) may affect the other (bradykinin production), or whether the number of mast cells at a specific body site and their reactivity to triggers such as pressure, allergens or MRGPRX2 agonists may influence the occurrence of HAE-C1-INH attacks at that site.

Quality evaluation methods of chinese medicine based on scientific supervision: recent research progress and prospects

Traditional Chinese medicine (TCM) is increasingly getting attention worldwide, as it has played a very satisfactory role in treating COVID-19 during these past 3 years, and the Chinese government highly supports the development of TCM. The therapeutical theory and efficacies of Chinese medicine (CM) involve the safety, effectiveness and quality evaluation of CM, which requires a standard sound system. Constructing a scientific and reasonable CM quality and safety evaluation system, and establishing high-quality standards are the key cores to promote the high-quality development of CM. Through the traditional quality control methods of CM, the progress of the Q-marker research and development system proposed in recent years, this paper integrated the research ideas and methods of CM quality control and identified effective quality parameters. In addition, we also applied these effective quality parameters to create a new and supervision model for the quality control of CM. In conclusion, this review summarizes the methods and standards of quality control research used in recent years, and provides references to the quality control of CM and how researchers conduct quality control experiments.

A Novel Perilla frutescens (L.) Britton Cell-Derived Phytocomplex Regulates Keratinocytes Inflammatory Cascade and Barrier Function and Preserves Vaginal Mucosal Integrity In Vivo

In the last years, the medicinal plant Perilla frutescens (L.) Britton has gained scientific interest because leaf extracts, due to the presence of rosmarinic acid and other polyphenols, have shown anti-allergic and skin protective potential in pre-clinical studies. Nevertheless, the lack of standardized extracts has limited clinical applications to date. In this work, for the first time, a standardized phytocomplex of P. frutescens, enriched in rosmarinic acid and total polyphenols, was produced through innovative in vitro cell culture biotechnology and tested. The activity of perilla was evaluated in an in vitro inflammatory model of human keratinocytes (HaCaT) by monitoring tight junctions, filaggrin, and loricrin protein levels, the release of pro-inflammatory cytokines and JNK MAPK signaling. In a practical health care application, the perilla biotechnological phytocomplex was tested in a multilayer model of vaginal mucosa, and then, in a preliminary clinical observation to explore its capacity to preserve vaginal mucosal integrity in women in peri-menopause. In keratinocytes cells, perilla phytocomplex demonstrated to exert a marked activity in epidermis barrier maintenance and anti-inflammatory effects, preserving tight junction expression and downregulating cytokines release through targeting JNK activation. Furthermore, perilla showed positive effects in retaining vaginal mucosal integrity in the reconstructed vaginal mucosa model and in vivo tests. Overall, our data suggest that the biotechnological P. frutescens phytocomplex could represent an innovative ingredient for dermatological applications.

MrgX2-SNAP-tag/cell membrane chromatography model coupled with liquid chromatography-mass spectrometry for anti-pseudo-allergic compound screening in Arnebiae Radix

Pseudo-allergic reactions (PARs) are IgE-independent hypersensitivity reactions. Mas-related G protein-coupled receptor-X2 (MrgX2) was proved the key receptor of PAR. The anti-pseudo-allergic compound discovery based on MrgX2 was of great value. Cell membrane chromatography (CMC) based on MrgX2 provides a convenient and effective tool in anti-pseudo-allergic compound screening and discovery, and further improvements of this method are still needed. In this work, SNAP-tag was introduced at C-terminal of Mas-related G protein-coupled receptor (MrgX2-SNAP-tag), and an MrgX2-SNAP-tag/CMC model was then conducted using CMC technique. Comparative experiments showed that the new model not only satisfied the good selectivity and specificity of screening but also exhibited more stable and longer life span than traditional MrgX2/CMC model. By coupling with HPLC-MS, two compounds were screened out from Arnebiae Radix and identified as shikonin and acetylshikonin. Nonlinear chromatography was performed to study the interactions between two screened compounds and MrgX2, and binding constant (K_A) of shikonin and acetylshikonin with MrgX2 were 2075.67 ± 0.34 M^-1 and 32201.36 ± 0.35 M^-1, respectively. Furthermore, β-hexosaminidase and histamine release assay in vitro demonstrated that shikonin (1-5 μM) and acetylshikonin (2.5-10 μM) could both antagonize C48/80-induced allergic reaction. In conclusion, the MrgX2-SNAP-tag/CMC could be a reliable model for screening pseudo-allergy-related components from complex systems.

Advances in cell membrane chromatography

Cell membrane chromatography (CMC) is a biomimetic chromatographic method based on the ability of membrane receptors to selectively interact with their ligands in vivo. Using membrane receptors as a stationary phase, the CMC method helps in determining the binding characteristics between ligands and membrane receptors and in efficiently identifying specific target components in a complex sample that produce the cellular biological effects of ligands (drugs, antibodies, enzymes, cytokines, etc.). CMC is an analytical tool for revealing characteristics of ligand-receptor interactions, screening and discovering target substances, and accurately controlling the quality of drugs. Since establishment of CMC in the early 1990s, with the rapid development of cell biology, significant progress has been made in the development of high-expression receptors, engineered cell cultures, and standardized preparations, which allowed in vitro immobilization of cell membrane receptors and miniaturization of binding assays. A variety of CMC models have been established using different membrane receptors as a stationary phase, and many new methods have been developed by combining CMC with high-performance liquid chromatography (HPLC)/mass spectrometry or HPLC-IT-TOF technologies. CMC methods have been widely used to study drug-receptor interactions and to screen complex samples for effective or harmful components.

Characterization of interactions between local anesthetics and histamine H1 receptor by cell membrane chromatography model

Local anesthetic has a wide application in clinical practice. However, angioedema, an adverse reaction caused by local anesthetics, has been reported to be related to histamine H₁ receptor (H₁R). Hence, an effective and practical method for investigating the interaction characteristics between local anesthetics and H₁R is needed. In this work, the competition binding assay and the relative standard method based on H₁R-HEK293/cell membrane chromatography (CMC) were developed to analyze the equilibrium dissociation constant (K_D) values of local anesthetics with H₁R. The activity of drugs toward H₁R was evaluated by intracellular Ca²⁺ imaging assay. Molecular docking was used to verify the interaction modes that occurred at the activate pocket of H₁R protein. Results showed that the local anesthetics can directly occupy histamine binding sites on H₁R, and the K_D values obtained from different CMC methods exhibited positive correlations with each other (p < 0.01). The K_D values of tetracaine, procaine, and lidocaine were much closer to that of histamine than bupivacaine and ropivacaine. This was not only in line with the Ca²⁺ responses in activating H₁R, but also consistent with the same amino acid residues shared with histamine in the H₁R active site. In conclusion, this study provided new insight into the interactions between local anesthetics and H₁R. The H₁R-HEK293/CMC methods developed in this study could be used to evaluate the interaction characteristics of those compounds acting on H₁R.