Modeling rapid and selective capture of nNOS–PSD-95 uncouplers from Sanhuang Xiexin decoction by novel molecularly imprinted polymers based on metal–organic frameworks

Vitro UPLC analysis and mass method identification, and in vivo or cellular immune anti-inflammatory function of Sanhuang Xiexin Decoction (SHXD)

ETHNOPHARMACOLOGICAL RELEVANCE

Sanhuang Xiexin Decoction (SHXD), consisting of Coptis chinensis Franch., Scutellaria baicalensis Georgi and Rheum palmatum L., is traditionally used for relieving fever, purging fire for removing toxins, eliminating phlegm and haemostasis, eliminating the wetness-evil from the upper warmer, clearing away the heat-evil and expelling superficial evils. Each of the three herbs contained in SHXD has been indicated to have anti-inflammatory effects in vivo, but its effects on rat NK-cell phenotypes remain unexplored, and the comprehensive mechanism of this compound SHXD in curing the inflammation induced by lipopolysaccharides (LPS) remains to be revealed.

AIM OF THE STUDY

The study aim was to assess the effect of SHXD on LPS-induced fever and inflammation in a rat model, reduce NLRP3 activation in NK cells expressing specific cell phenotype antibodies and determine the therapeutic value of this approach in vivo.

MATERIALS AND METHODS

SHXD extract was prepared and analysed by the developed ultra-performance liquid chromatography (UPLC) method for the simultaneous detection of 14 compounds. The main peaks were firstly identified on an Orbitrap via high resolution tandem mass spectrometry (MS). Then, the extract was used in the rat model of LPS-induced inflammation and fever for pharmacologically study the effects of drug treatment. Peripheral blood lymphocyte cells were isolated from the animals, including those subjected to the SHXD extract treatment, and the cell phenotype was determined prior to cell culture and after treating the cell cultures with the extract. The phenotypes of cells harvested using CD3, CD4, CD8a, CD81, CD161 and CD86 antibodies were used to verify the enhanced memory of the peripheral blood lymphocytes cells (PBMC) that were induced into nature killer (NK) cells.

RESULTS

The SHXD extract was prepared, analysed and identified via quality control equipment and was observed to have pharmacological effects that reduced NLRP3 activation and fever in rats. The production of NK cells and peripheral blood lymphocytes was induced by the SHXD extract, which manifested as increased levels of CD4+, CD8a+, CD81+, CD161+ and CD86+ cells. The levels of CD3+ cells were significantly different between the model group and the drug-treated or control groups (p < 0.01) with dose independence, while the levels of CD4+ cells were not significantly different between the drug-treated and control groups, with a trend towards lower levels in the model group with dose independence. The levels of CD4+ cells was significantly different between the drug-treated group and the model groups with dose independence (p < 0.05). The levels of CD86+ cells were not significantly different between the drug-treated group and the model and control groups. The levels of CD8a + cells was significantly different between the model group and the drug and control groups (p < 0.05, dose 2.0 μg/ml), with higher levels in the drug-treated group. The levels of CD3+, CD4+, CD8a + cells in the drug treated group have dose dependence with SHXD.

CONCLUSIONS

This experiment revealed that SHXD reduced NLRP3 activation in the blood of LPS-treated rats, which occurred through the activation of NK cells that expressed CD3, CD8a and CD161. SHXD may possess anti-inflammatory effect via activacting the one of major pharmacology effcet of NK cells that expressed CD3, CD8a and CD161 phenotypes expression. This result demonstrates that SHXD may possess ability to enhance the memory of peripheral blood lymphocytes and natural killer cells.

Metal-Organic Frameworks-Based Nanoplatforms for the Theranostic Applications of Neurological Diseases

Neurological diseases are the foremost cause of disability and the second leading cause of death worldwide. Owing to the special microenvironment of neural tissues and biological characteristics of neural cells, a considerable number of neurological disorders are currently incurable. In the past few years, the development of nanoplatforms based on metal-organic frameworks (MOFs) has broadened opportunities for offering sensitive diagnosis/monitoring and effective therapy of neurology-related diseases. In this article, the obstacles for neurotherapeutics, including delayed diagnosis and misdiagnosis, the existence of blood brain barrier (BBB), off-target treatment, irrepressible inflammatory storm/oxidative stress, and irreversible nerve cell death are summarized. Correspondingly, MOFs-based diagnostic/monitoring strategies such as neuroimaging and biosensors (electrochemistry, fluorometry, colorimetry, electrochemiluminescence, etc.) and MOFs-based therapeutic strategies including higher BBB permeability, targeting specific lesion sites, attenuation of neuroinflammation/oxidative stress as well as regeneration of nerve cells, are extensively highlighted for the management of neurological diseases. Finally, the challenges of the present research from perspective of clinical translation are discussed, hoping to facilitate interdisciplinary studies at the intersections between MOFs-based nanoplatforms and neurotheranostics.

Metal-Organic Frameworks Meet Molecularly Imprinted Polymers: Insights and Prospects for Sensor Applications

The use of porous materials as the core for synthesizing molecularly imprinted polymers (MIPs) adds significant value to the resulting sensing system. This review covers in detail the current progress and achievements regarding the synergistic combination of MIPs and porous materials, namely metal/covalent-organic frameworks (MOFs/COFs), including the application of such frameworks in the development of upgraded sensor platforms. The different processes involved in the synthesis of MOF/COF-MIPs are outlined, along with their intrinsic properties. Special attention is paid to debriefing the impact of the morphological changes that occur through the synergistic combination compared to those that occur due to the individual entities. Thereafter, the strategies used for building the sensors, as well as the transduction modes, are overviewed and discussed. This is followed by a full description of research advances for various types of MOF/COF-MIP-based (bio)sensors and their applications in the fields of environmental monitoring, food safety, and pharmaceutical analysis. Finally, the challenges/drawbacks, as well as the prospects of this research field, are discussed in detail.

Fabrication of multifunctional metal-organic frameworks nanoparticles via layer-by-layer self-assembly to efficiently discover PSD95-nNOS uncouplers for stroke treatment

Background

Disruption of the postsynaptic density protein-95 (PSD95)—neuronal nitric oxide synthase (nNOS) coupling is an effective way to treat ischemic stroke, however, it still faces some challenges, especially lack of satisfactory PSD95-nNOS uncouplers and the efficient high throughput screening model to discover them.

Results

Herein, the multifunctional metal–organic framework (MMOF) nanoparticles as a new screening system were innovatively fabricated via layer-by-layer self-assembly in which His-tagged nNOS was selectively immobilized on the surface of magnetic MOF, and then PSD95 with green fluorescent protein (GFP-PSD95) was specifically bound on it. It was found that MMOF nanoparticles not only exhibited the superior performances including the high loading efficiency, reusability, and anti-interference ability, but also possessed the good fluorescent sensitivity to detect the coupled GFP-PSD95. After MMOF nanoparticles interacted with the uncouplers, they would be rapidly separated from uncoupled GFP-PSD95 by magnet, and the fluorescent intensities could be determined to assay the uncoupling efficiency at high throughput level.

Conclusions

In conclusion, MMOF nanoparticles were successfully fabricated and applied to screen the natural actives as potential PSD95-nNOS uncouplers. Taken together, our newly developed method provided a new material as a platform for efficiently discovering PSD95-nNOS uncouplers for stoke treatment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01583-7.

A semi-covalent molecularly imprinted fluorescent sensor for highly specific recognition and optosensing of bisphenol A

A novel mesoporous fluorescent molecularly imprinted sensor for selective detection of bisphenol A (BPA) in food materials was fabricated via a semi-covalent imprinting method. The imprinting precursor that served as an alternative template molecule for BPA was prepared via thermally reversible isocyanate bonding, which effectively improved the imprinting efficiency for the molecularly imprinted sensor. Carbon dots (CDs) were embedded in mesoporous silica as signal recognition elements that exhibited quenching upon BPA binding. Subsequently, through the sol-gel process, the molecularly imprinted layer was coated on the CDs silica layer and provided specific recognition sites for BPA. The composite of CDs embedded in the mesoporous molecularly imprinted polymer (CDs@MIP) was characterized with scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller measurements and thermogravimetric analysis. The mechanism of carbon dots quenching and the high selectivity of CDs@MIP towards BPA were explored. The linear response range of the sensor was from 0.025 mg L^-1 to 2 mg L^-1 with a limit of detection of 0.016 mg L^-1. The method was successfully applied for the determination of food samples and recoveries ranged from 92.5% to 101.1%. The BPA contents in actual samples were determined using high performance liquid chromatography and the proposed sensor, showing no significant difference between the two methods.