Li-Xin Gao’s research while affiliated with Shanghai Institute of Materia Medica and other places

Introduction Although the development of SHP2 inhibitors has made striking progress, there is no inhibitor in clinical evaluation because of the potential side effects induced by poor drug distribution. Fluorescence imaging technology is widely used in the process of diagnosis and treatment of diseases because of the advantages of rapid imaging and non-destructive detection and might provide a new way to explore the mechanism of drug-target interactions in intact tissue. Method A series of 2-quinolone derivatives as fluorescent inhibitors against SHP2 were designed and synthesized, and their spectral properties and biological activities were evaluated in this report. The representative compound 8A had excellent fluorescence properties (λ : 562 nm, Stokes shift: 170 nm, fluorescence quantum yield: 0.072) and optical stability. Results Moreover, compound 8A emitted a blue signal in SHP2WT U2OS cells and inhibited the SHP2 enzyme abilities (IC50: 20.16 ± 0.95 μM) without the extra combination of suitable fluorophores, linker, or selectiveactivated molecules. Conclusion Therefore, we hope that compound 8A could act as a lead to develop novel, convenient, and bifunctional chemical tools to explore the mechanism of drug-target interactions in intact tissue and promote the integrated research progress of diagnosis and treatment of SHP2 related diseases.

Liver fibrosis, one of the leading causes of morbidity and mortality worldwide, lacks effective therapy. The activation of hepatic stellate cells (HSCs) is the dominant event in hepatic fibrogenesis. Luteolin-7-diglucuronide (L7DG) is the major flavonoid extracted from Perilla frutescens and Verbena officinalis. Their beneficial effects in the treatment of liver diseases were well documented. In this study we investigated the anti-fibrotic activities of L7DG and the potential mechanisms. We established TGF-β1-activated mouse primary hepatic stellate cells (pHSCs) and human HSC line LX-2 as in vitro liver fibrosis models. Co-treatment with L7DG (5, 20, 50 μM) dose-dependently decreased TGF-β1-induced expression of fibrotic markers collagen 1, α-SMA and fibronectin. In liver fibrosis mouse models induced by CCl4 challenge alone or in combination with HFHC diet, administration of L7DG (40, 150 mg·kg-1·d-1, i.g., for 4 or 8 weeks) dose-dependently attenuated hepatic histopathological injury and collagen accumulation, decreased expression of fibrogenic genes. By conducting target prediction, molecular docking and enzyme activity detection, we identified L7DG as a potent inhibitor of protein tyrosine phosphatase 1B (PTP1B) with an IC50 value of 2.10 µM. Further studies revealed that L7DG inhibited PTP1B activity, up-regulated AMPK phosphorylation and subsequently inhibited HSC activation. This study demonstrates that the phytochemical L7DG may be a potential therapeutic candidate for the treatment of liver fibrosis.

Protein tyrosine phosphatase 1B (PTP1B) has proven to be an attractive target for the treatment of cancer, diabetes and other diseases. Although many PTP1B inhibitors with various scaffolds have been developed, there is still a lack of PTP1B inhibitor with high specificity and acceptable pharmacological properties. Therefore, it is urgent to develop more methods to explore complex action mode of PTP1B and ligands for designing ideal PTP1B modulators. In this work, we developed a potential molecular dynamics (MD) analytic mode to analyze the mechanism of active compounds 6a and 6e against PTP1B from different perspectives, including the stable ability, interactions and binding site of ligand and protein, the binding energy, relative movement between residues and changes in protein internal interactions. The simulated results demonstrated that compound 6a bound more stably to the active pocket of PTP1B than 6e due to its smaller molecular volume (326 Å3), matched electronegativity, and enhanced the positive correlation motion of residues, especially for WPD loop and P loop. Lastly, compound 6a as a competitive inhibitor for PTP1B was verified by enzyme kinetic assay. This work successfully studied the mechanism of compound 6a against PTP1B from various aspects, enriched the analysis of interaction mode between PTP1B and inhibitors. In summary, we hope that this work could provide more theoretical information for designing and developing more novel and ideal PTP1B inhibitors in the future.

Fluorescence imaging is conducive to establish a bridge between molecular biology and clinical medicine, and provides new tools for disease process research, early diagnosis, and efficacy evaluation, because of the advantages of rapid imaging and nondestructive detection. Herein, a series of fluorescent molecules with thiadiazole, or thiazole, or benzothiazole cores were designed and synthesized to develop more excellent fluorescent molecules in bio‐imaging. According to theoretical and experimental methods, we found that benzothiazole derivative 14 B with conjugate expansion by (4‐aminophenyl) ethynyl group was the most excellent fluorescent molecule among all the investigated compounds and exhibited low cytotoxicity and strong blue and green fluorescence by confocal cell imaging.