HPLC with cellulose Tris (3,5‐DimethylPhenylcarbamate) chiral stationary phase: Influence of coating times and coating amount on chiral discrimination

Coating cellulose tris (3,5‐dimethylphenylcarbamate) (CDMPC) on silica gels with large pores have been demonstrated as an efficient way for the preparation of chiral stationary phase (CSP) for high‐performance liquid chromatography (HPLC). During the process, a number of parameters, including the type of coating solvent, amount of coating, and the method for subsequent solvent removing, have been proved to affect the performance of the resultant CSPs. Coating times and the concentration of coating solution, however, also makes a difference to CSPs' performance by changing the arrangement of cellulose derivatives while remaining the coating amount constant, have much less been studied before, and thereby, were systematically investigated in this work. Results showed that CSPs with more coating times exhibited higher chiral recognition and column efficiency, suggesting that resolution was determined by column efficiency herein. Afterwards, we also investigated the effect of coating amount on the performance of CSPs, and it was shown that the ability of enantio‐recognition did not increase all the time as the coating amount; and four of seven racemates achieved best resolution when the coating amount reached to 18.37%. At the end, the reproducibility of CDMPC‐coated CSPs were further confirmed by two methods, ie, reprepared the CSP‐0.15‐3 and reevaluated the effect of coating times.     

Molecular Modelling reveals the inhibition mechanism and structure–activity relationship of curcumin and its analogues to Staphylococcal aureus Sortase A

Previous studies found that the activity of Sortase A, a bacterial surface protein from Staphylococcus aureus, was inhibited by curcumin and its analogues. To explore this inhibitory mechanism, Sortase A and its inhibitors in complex systems were studied by molecular docking, molecular modelling, binding energy decomposition calculation and steered molecular dynamics simulations. Energy decomposition analysis indicated that PRO-163, LEU-169, GLN-172, ILE-182 and ILE-199 are key residues in Sortase A-inhibitor complexes. Furthermore, interactions between the methoxyl group on the benzene ring in the conjugated molecule (curcumin, demethoxycurcumin, bisdemethoxycurcumin) and VAL-168, LEU-169 and GLN-172 induce the inhibitory activity based on the energy decomposition and distance analyses between the whole residues and inhibitors. However, because of its coiled structure, the non-conjugated molecule, tetrahydrocurcumin, with key residues in the binding sites of Sortase A, interacted weakly with SrtA, leading to the loss of inhibitory activity. Based on these results, the methoxyl group on the benzene ring in the conjugated molecule largely influenced the inhibitory activity of the Sortase A inhibitors.     

Repellent action and contact toxicity mechanisms of the essential oil extracted from Chinese chive against Plutella xylostella larvae

Botanical pesticides play increasingly important roles in the control of agricultural pests. In this study, the insecticidal effects, specifically the repellent action and contact toxicity, of the essential oil extracted from Chinese chive (EOC) against Plutella xylostella larvae were confirmed. The mechanisms of repellent’s action were studied using electroantennograms (EAGs), and the effects on glutathione S‐transferase (GST), carboxylesterase (CarE), and acetyl cholinesterase were investigated after EOC treatments. The EOC affected the EAG results and inhibited the activities of GST and CarE in treated P. xylostella larvae, which could explain its insecticidal effects. And, four pyrazines showed greater repellent activities than that of the EOC, which was confirmed as the main active compounds of EOC.     

Phosphoinositide-dependent kinase 1–associated glycolysis is regulated by miR-409-3p in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most popular kidney cancer in adults. Metabolic shift toward aerobic glycolysis is a fundamental factor for ccRCC therapy. MicroRNAs (miRNAs) are thought to be important regulators in ccRCC development and progression. Phosphoinositide-dependent kinase 1 (PDK1) is required for metabolic activation; however, the role of PDK1-induced glycolytic metabolism regulated by miRNAs is unclear in ccRCC. So, the purpose of the current study is to elucidate the underlying mechanism in ccRCC cell metabolism mediated by PDK1. Our results revealed that miR-409-3p inhibited glycolysis by regulating PDK1 expression in ccRCC cells. We also found that miR-409-3p was regulated by hypoxia. Our results indicated that PDK1 facilitated ccRCC cell glycolysis, regulated by miR-409-3p in hypoxia.     

MicroRNA-424 regulates epithelial-mesenchymal transition of endometrial carcinoma by directly targeting insulin-like growth factor 1 receptor

Although numerous miRNAs are reported to contribute to the carcinogenesis of malignant tumor, the specific role of miR-424 in endometrial carcinoma is seldom reported. To explore the effect of miR-424 on epithelial-mesenchymal transition and its underlying mechanism, we detected miR-424 expression in endometrial carcinoma tissue and cells. We found that miR-424 was significantly downregulated in endometrial carcinoma tissues and cells, especially in HEC-1B cells. To perform the functional analysis, we transfected HEC-1B with miR-424-mi, miR-424-inh, mi-control, and inh-control, respectively. We found that overexpression of miR-424 significantly decreases cell proliferation and migration, accompanied with the increased E-cadherin/Vimentin expression and the transition of mesenchymal to epithelial cell phenotype. We identified that insulin-like growth factor-1 receptor (IGF-1R) was a potential target of miR-424 by computational analysis followed by luciferase reporter assays. Of note, we found that the downregulation of miR-424 in HEC-1B cells enhanced endogenous IGF-1R expression. Further mechanistic analysis revealed that forced expression of IGF-1R in miR-424-mim transfected cells remedied the weakened migration resulting from overexpression of IGF-1R. Taken together, the results of the current study demonstrated that miR-424 was a tumor suppressor for endometrial carcinoma and a favorable factor against tumor progression through targeting IGF-1R, thus providing a target for the treatment of endometrial carcinoma.     

Isofraxidin attenuates IL-1β-induced inflammatory response in human nucleus pulposus cells

Inflammation has been demonstrated to be the key factor for intervertebral disc degeneration (IVD), which remains a major public health problem. Isofraxidin is a coumarin compound that possesses strong anti-inflammatory activity. However, the role of isofraxidin in IVD remains unclear. The aim of this study was to evaluate the effects of isofraxidin on inflammatory response in human nucleus pulposus cells (NPCs) exposed to interleukin-1β (IL-1β). The results proved that isofraxidin attenuated the IL-1β-induced significant increases in inflammatory mediators and cytokines including nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α), and IL-6. Besides, isofraxidin also inhibited the induction effect of IL-1β on matrix metalloproteinases (MMP)-3 and MMP-13. Moreover, the NF-κB activation caused by IL-1β was significantly inhibited by isofraxidin treatment. These findings suggested that isofraxidin alleviates IL-1β-induced inflammation in NPCs. Our work provided an idea that isofraxidin might act as a novel preventive role in IVD.     

Analysis of long noncoding RNA expression profiles in the whole blood of neonates with hypoxic-ischemic encephalopathy

Long noncoding RNAs (lncRNAs) have been shown to participate in many biological processes. To investigate the expression profiles of lncRNAs and their potential functions in neonatal hypoxic-ischemic encephalopathy (HIE), we detected the lncRNA and messenger RNA (mRNA) expression in the peripheral blood samples from HIE patients and controls using a microarray. A total of 376 lncRNAs and 126 mRNAs were differentially expressed between the HIE and the non-HIE samples (fold change > 2). Quantitative real-time polymerase chain reaction was used to validate the microarray data. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analysis were performed to determine the gene function. Furthermore, the lncRNA-mRNA coexpression network was generated to predict the potential targets of lncRNAs. In conclusion, our study first demonstrated the differential expression profiles of lncRNAs in the whole blood of infants with HIE and may provide a new view of the distinct lncRNA functions in HIE.