Latest ArticlesThe Dionex CaboPacTM PA10 BioLCTM Analyical 2 mm × 250 mm column was used with a protective column (Dionex CaboPacTM PA10 BioLCTM Guard 2 mm × 50 mm). 100 mmol·L-1 sodium hydroxide solution was used as eluent; the flow rate was 0.25 mL·min-1. Sample tray temperature: 35 ℃. The pulse amperometric detector was adopted, and the waveform was Gold CWE, Ag-AgCl RE, Carbo, Quad. The samples were cultured with 8 concentrations of glycogen substrates (0.31, 1.25, 2.5, 5, 10, 20, 30, and 40 mg·mL-1). D-Glucose concentrations were measured at 5 different time points (T0, T1, T2, T3 and T4). The glucose concentration from T1 to T4 minus the glucose concentration at T0. The reaction rate was calculated at different glycogen substrate concentrations. These reaction rates are plotted against substrate concentrations using Michaelis-Menten equation. The kinetic parameters were expressed as Vmax (nmol·mg-1·min-1) and Km (mg·mL-1). The RSD of glucose standard curve R2 (n = 6, linear range: 1.25-500 μmol·L-1) was 0.1% and the RSD (n = 6) of the slope of the standard curve was 2.2%. The mean limit of quantitation was 0.14 μmol·L-1, and the mean limit of detection was 0.05 μmol·L-1. The RSD of Km and Vmax were 4.4% and 4.6% respectively in three separate experiments. The durability of the method was good. The method was developed for the on-line automatic determination of the hydrolysis kinetics of acid α-glucosidase (GAA) for injection by ion chromatography. The method has good precision, repeatability and durability, and can be used for the determination of glycogen hydrolysis kinetics of GAA for injection, and could reference value for the enzyme kinetics evaluation of recombinant enzyme replacement therapy.
The methanol extract of Huperzia serrata was separated and purified by ODS, AB-8 macroporous adsorption resin, dextran gel Sephadex LH-20 and silica gel column chromatography combined with the semi-pre HPLC. The chemical structures of the isolated compounds were identified by MS, IR, NMR, etc. Four compounds were isolated from Huperzia serrata and identified, named as serratinine C (1), lycobeline C (2), diphaladin A (3) and crenatine (4). Compound 1 is a new alkaloid, compounds 2-4 were isolated for the first time. In vitro biological activity experiments showed that compound 1 could significantly reduce the levels of nitric oxide and reactive oxygen species in glial cells induced by lipopolysaccharide and had significant antioxidant biological activity.
The 95% ethanol extract of Poria cocos was separated and purified by ODS, MCI gel CHP20 and silica gel column chromatography combined with the semi-preparative HPLC. The chemical structures of the isolated compounds were identified by NMR, MS, IR, and calculated NMR methods. Seven compounds were isolated from Poria cocos and identified as 20S-2β, 3α, 15α, 19, 20-hydroxy-pregnane-7-ene (1), dehydroeburicoic acid monoacetate (2), eburicoic acid acetate (3), dehydroeburicoic acid (4), eburicoic acid (5), dehydropachymic acid (6), pachymic acid (7). Compound 1 is a new pregnane steroid.
Arginase 1 deficiency (ARG1-D) is a rare genetic metabolic disorder that leads to progressive spastic paralysis, cognitive impairment, and seizures. Recombinant human arginase 1 (rhArg1) is a potential therapeutic agent for this condition, but its clinical application is limited by low activity and short half-life. In this study, we employed directed evolution to address these issues. A random mutation library of rhArg1 was constructed using error-prone PCR, and high-throughput screening was used to identify mutants with enhanced activity. Site-saturation mutagenesis was also performed to investigate the effects of residues R21 and V182 on enzyme activity. Our findings revealed that under reaction conditions devoid of Mn2+, the kcat values of the mutants V182D, V182S, V182H, and R21N increased by 2.0, 1.9, 1.7, and 1.3 times respectively, compared to rhArg1. The kcat/Km values of mutants V182D, V182S, R21D, and R21N were 2.1, 1.7, 1.4, and 1.4 times higher than those of rhArg1, respectively. Additionally, mutants R21D and V182L showed enhanced substrate affinity. Through directed evolution and site-saturation mutagenesis, we successfully obtained rhArg1 mutants with improved activity, thereby enhancing its potential for clinical application.
The anti-apoptotic members of Bcl-2 family proteins, Bcl-2 and Mcl-1, are considered therapeutic targets of various cancers. In this article, we developed four hydrophobic tag (HyT)-based protein degraders of Bcl-2/Mcl-1, based on a Bcl-2/Mcl-1 dual inhibitor S1-6, and tested their capability in Bcl-2/Mcl-1 degradation and apoptotic induction in MCF-7 cells. Interestingly, different linkers in the HyT degraders led to selective Bcl-2/Mcl-1 degradation, though the degraders S1-D1-S1-D4 maintained the pan-Bcl-2 family binding capacity. Among them, S1-D2 and S1-D4, two compounds bearing a hydrophobic linker or a PEG linker, were observed to potently and selectively induce the ubiquitination and proteasomal degradation of Bcl-2 and Mcl-1 in living cells, with a degradation rate of more than 80% or 60%, respectively. Moreover, the HyT-based degraders showed increased lethality of cancer cells compared to the parent inhibitor S1-6, demonstrating that the advantage of degraders to the occupancy-based inhibitors.
The gut microbiota plays a crucial role in the development of colorectal cancer (CRC). The imbalanced gut microbiota causes damage to the body and disrupts bile acids metabolism, increases susceptibility to CRC, and affects the signaling of farnesol X receptor (FXR), thereby promoting CRC progression. Traditional Chinese medicine has unique advantages in the treatment of CRC due to its synergistic regulatory effects of multiple components, targets, and pathways. It can regulate gut microbiota, intervene in bile acids metabolism, and activate its receptor FXR to inhibit the occurrence and development of CRC. Based on this, this article discusses the main role of the gut microbiota-bile acids-FXR axis in the development of CRC, and reviews the anti CRC effects and mechanisms of traditional Chinese medicine intervention on gut microbiota-bile acids-FXR axis, in order to provide new ideas and methods for the prevention and treatment of CRC.
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates gene expression in a range of cells, including immune and epithelial cells. AhR signaling plays important roles in the immune system in both health and disease states. Tapinarof is a first-in-class small-molecule topical therapeutic AhR modulating agent launched for the treatment of psoriasis. To improve the activity and chemical stability of Tapinarof, a series of 2-phenylchromen-4-one derivatives were designed, synthesized and evaluated as novel AhR agonists. Compounds 5a, 5c, 5e and 5f potently activated AhR with an EC50 value of 7, 9, 6 and 6 nmol·L-1, respectively, which are 10-14 fold more potent than Tapinarof. Compounds 5a and 5e exhibit comparable inhibitory effects on IFN-γ production as Tapinarof. Furthermore, compounds 5a-5f exhibited favorable photochemical stability compared to Tapinarof. The compounds may eventually serve as lead compounds for the development of new AhR agonists.
The deubiquitinases (DUBs), as the crucial peptidohydrolases in the ubiquitin system, can reverse and strictly regulate ubiquitination and play key roles in various biological processes, including the regulation of protein stability, cell signal transduction. Ubiquitin-specific protease 28 (USP28) involves multiple cancer-related signaling pathways by enhancing the stability of various cancer-related proteins, and is closely associated with the progression of colorectal, breast cancer, lung carcinomas, and pancreatic cancer. USP28 has been considered as a promising drug target in anticancer therapy, and the development of USP28 inhibitors has made some progress. In this article, we review the structure of USP28 and its interaction with substrates, discuss the research progress of USP28 in cancers and summarize the development of USP28 inhibitors.
Heart failure with preserved ejection fraction (HFpEF) accounts for about half of the number of patients with heart failure. In addition to the typical features of heart failure such as myocardial stiffness and diastolic function impairment, the key characteristic of HFpEF is the normal left ventricular ejection fraction, which increases the difficulty of clinical diagnosis. QiShenYiQi Dripping Pills (QSYQ) is a standardized traditional Chinese medicine approved by the China Food and Drug Administration (CFDA), and many clinical studies have demonstrated the efficacy and safety of QSYQ in the treatment of heart failure with reduced ejection fraction, but the role of QSYQ in HFpEF has not been clarified. In this paper, high fat diet (HFD) and drinking water containing N-nitro-L-arginine methyl ester (L-NAME, 0.5 g·L-1, pH=7.4) were used in C57BL/6N male mice to construct the classical HFpEF model (the experiment was approved by the Animal Ethics Committee of Hefei University of Technology, the approval number is HFUT20220921002), and at the 8th week, the mice were dosed with ① empagliflozin, ② low-dose QSYQ (LQ), ③ high-dose QSYQ (HQ), ④ empagliflozin plus low-dose QSYQ (ELQ) for 4 weeks, the body weight of the mice was recorded during the experiment, echocardiography, blood pressure and glucose tolerance were detected and the exercise capacity of mice was evaluated, and pathological and biochemical experiments were used to detect cardiac fibrosis, liver fibrosis and serum biochemical indexes in mice, RNAseq assay was performed with mice heart tissues. The results showed that QSYQ as well as QSYQ+empagliflozin could significantly reduce the body weight, improve diastolic function and hypertension, improve glucose tolerance and enhance exercise ability of HFpEF mice. At the biochemical and molecular levels, QSYQ and QSYQ+empagliflozin can reduce the cross-sectional area of cardiomyocytes and reduce cardiac collagen contents, thereby alleviating myocardial hypertrophy and fibrotic phenotypes, and improve metabolic disorders. The RNAseq results suggest that the function of QSYQ in improving HFpEF may be related to calsequestrin 1. In conclusion, this study shows that QSYQ and QSYQ+empagliflozin can significantly improve HFpEF-related cardiac dysfunction and metabolic disorders, which provides a theoretical basis for the clinical treatment of HFpEF.
As a major global public health problem, pulmonary diseases threaten human life and health while causing a huge economic burden. The messenger RNA (mRNA)-based inhalation preparation, which effectively targets pulmonary cells can overcome the problems of traditional therapy, such as high side effects, low pulmonary bioavailability, and difficulty in synthesizing target proteins in vitro, thus providing new ideas for the treatment of pulmonary diseases. However, as the lung structure is complex and mRNA has trouble entering cells, researchers have been attempting to develop a suitable nano delivery system for higher delivery efficiency. This review introduces the barriers to pulmonary delivery, discusses the recent research development of the mRNA pulmonary delivery systems, including lipid nanoparticles, polymeric nanoparticles, polypeptides and exosomes, summarizes their limitations and looks forward to the application of mRNA inhalation preparations.