Repurposing niclosamide for intestinal decolonization of vancomycin-resistant enterococci

Enterococci are commensal micro-organisms present in the gastrointestinal tract of humans. Although normally innocuous to the host, strains of enterococcus exhibiting resistance to vancomycin (VRE) have been associated with high rates of infection and mortality in immunocompromised patients. Decolonization of VRE represents a key strategy to curb infection in highly-susceptible patients. However, there is a dearth of decolonizing agents available clinically that are effective against VRE. The present study found that niclosamide, an anthelmintic drug, has potent antibacterial activity against clinical isolates of vancomycin-resistant Enterococcus faecium (minimum inhibitory concentration 1–8?µg/mL). E. faecium mutants exhibiting resistance to niclosamide could not be isolated even after multiple (10) serial passages. Based upon these promising in-vitro results and the limited permeability of niclosamide across the gastrointestinal tract (when administered orally), niclosamide was evaluated in a VRE colonization-reduction murine model. Remarkably, niclosamide outperformed linezolid, an antibiotic used clinically to treat VRE infections. Niclosamide was as effective as ramoplanin in reducing the burden of vancomycin-resistant E. faecium in the faeces, caecal content and ileal content of infected mice after only 8 days of treatment. Linezolid, in contrast, was unable to decrease the burden of VRE in the gastrointestinal tract of mice. The results obtained indicate that niclosamide warrants further evaluation as a novel decolonizing agent to suppress VRE infections.     

Effects of squalene on expression of LDLR in HepG2 cells and its mechanism北大核心CSCD

Aim To investigate the effect of squalene on LDLR expression in HepG2 cells and its mechanism of down-regulated cholesterol. Methods The proliferation of HepG2 cells exposed to squalene at different concentrations was measured by MTT assay. The effect of squalene on the expression of LDLR in HepG2 cells was measured by flow cytometry and fluorescence mi-croscopy. The effect of different concentrations of squalene on the interaction between SCAP and Insig2, two key protein molecules of SREBP pathway, was assayed by FRET technology. Results MTT results showed that squalene had inhibitory effect on the proliferation of HepG2 cells in a dose-dependent manner. Flow cytometry and fluorescence microscopy results showed that squalene enhanced LDLR expression in HepG2 cells compared with the control group. The results of FRET technology revealed that compared with model control group, the YFP fluorescence value in Squalene group dramatically declined, and the YFP fluorescence value of each drug group decreased with the range of 5-25 |xmol L1 squalene concentration. Conclusions Squalene may promote the expression of LDLR in HepG2 cells through inhibiting the interaction between SCAP and Insig2 proteins in SREBP pathway, which may confirm that squalene is a potential novel drug for the down-regulation of cholesterol level. © 2018 Publication Centre of Anhui Medical University. All rights reserved.     

Delivery of radix ophiopogonis polysaccharide via sucrose acetate isobutyrate-based in situ forming systems alone or combined with its mono-PEGylation

This work aimed to achieve long-lasting delivery of radix ophiopogonis polysaccharide (ROP) by sucrose acetate isobutyrate (SAIB)-based in situ forming systems (ISFSs) alone or combined with mono-PEGylation of ROP. When the ‘90%SAIB/10% solvent’ system was used, the mean residence time (MRT) of ROP was prolonged by 4.3 5?～?7.00 times and the initial release rate was reduced significantly. However, this system was only suitable for days-long sustained release of ROP in short-term therapy. As to the ‘SAIB/additives/solvent’ system containing mono-PEGylated ROP, the results indicated that SAIB/poly(d,l-lactide-co-glycolide) (PLGA)/N-methyl-2-pyrrolidone (NMP) was superior to SAIB/polylactic acid (PLA)/NMP and SAIB/PLA/ethanol in controlled release. Moreover, weeks- to months-long (16–60 d) smooth release of ROP could be achieved by varying the concentration (10–30%) and molecular weight (MW) of PLGA (10–50?kDa) or by employing a moderate MW of PEGylated ROP (～20 or ～30?kDa). With further increasing the conjugate MW to ～40?kDa, the contribution of drug elimination to its plasma retention seemed to surpass that of the SAIB-based system, resulting in that the system no longer had an obvious influence on the in vivo behavior of the conjugate. Besides, the results of host response confirmed that with less solvent being used, the SAIB-based systems showed a higher biocompatibility than the PLGA-based systems, suggesting that they could be freely chosen in the prevention and/or cure of chronic diseases.     

Two flavonol glycosides from <Emphasis Type="Italic">Liparis bootanensis</Emphasis>

Two new flavonol glycosides, bootanenside I and II (1 and 2), along with ten known compounds (3–12), were isolated from whole plant of Liparis bootanensis Griff. Their structures were elucidated on the basis of extensive spectroscopic analyses, including high-resolution electrospray-ionization mass spectrometry (HR–ESIMS) and one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR). The cytotoxicity of the compounds was investigated against HCT116 human cancer cell line, revealing that none of them possessed considerable cytotoxic activity. Bioassays of the new metabolites showed that compounds 1 and 2 displayed moderate in vitro antiinflammatory activity by inhibiting expression of inducible nitric oxide synthase (iNOS) protein in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells.     

Mechanism of acid production and secretion by osteoclasts]

Osteoclasts are primary cells responsible for bone resorption. The most characteristic feature of osteoclasts is the presence of ruffled borders and clear zones. The resorbing area under the ruffled border of osteoclasts is acidic, which favors dissolution of bone mineral. In bone-resorbing osteoclasts, hydrogen ions are provided by carbonic anhydrase II, which catalyzes the hydration of CO2 to H2CO3. Recently, it has been shown that the proton pump of the vacuolar H(+)-ATPase type exists in the ruffled border membranes of osteoclasts. Secretion of hydrogen ions by osteoclasts generates an equal amount of cytoplasmic base equivalents, principally as HCO3-. Osteoclasts have a chloride/bicarbonate exchanger, which normalizes the intracellular pH when osteoclasts actively resorb bone. In this paper, we review the mechanism of the acid secretion by osteoclasts.     

百草枯对A549细胞中解整合素-金属蛋白酶17表达的影响

目的构建体外百草枯（paraquat,PQ）细胞纤维化模型,观察PQ对A549细胞中解整合素-金属蛋白酶17（ADAM17）表达的影响,探讨ADAM17在PQ中毒致肺纤维化中的作用。方法体外培养A549细胞,分为正常对照组、不同浓度PQ组,应用CCK-8检测细胞活力,筛选PQ浓度和时间,显微镜下观察细胞形态,ELISA测定各组纤维化标志物I型胶原（type I collagen,Col I）和纤连蛋白（fibronectin,FN）的表达,建立细胞纤维化模型;免疫细胞化学检测A549细胞中ADAM17的分布情况,RT-PCR和Western blot分别半定量检测ADAM17 mRNA及蛋白水平的表达情况。结果（1）随着PQ浓度增加及作用时间延长,A549细胞活力呈下降趋势,差异有统计学意义（P〈0.05）,呈剂量依赖性和时间依赖性。（2）正常的A549细胞融合呈铺路石样生长,排列比较紧密,经PQ诱导后细胞排列较松散,细胞间连接变疏松,部分细胞溶解、死亡。（3）ELISA显示,随PQ浓度增加,Col I和FN表达增强,差异有统计学意义（P〈0.05）;随PQ时间延长,Col I和FN表达也逐渐增强,差异有统计学意义（P〈0.05）,成功建立PQ细胞纤维化模型。（4）免疫细胞化学显示,ADAM17在A549细胞胞浆表达。（5）RT-PCR和Western blot表明,随着PQ浓度增加,ADAM17 mRNA及蛋白水平表达明显增加,差异有统计学意义（P〈0.05）,以PQ 200 umol/L时最为明显。随着PQ作用时间延长,ADAM17 mRNA及蛋白表达水平也明显增加,差异有统计学意义（P〈0.05）,在24 h达到高峰。结论百草枯可引起肺泡上皮细胞形态学改变,导致细胞损伤,成功建立细胞的纤维化模型,对A549细胞的毒性作用具有剂量和时间依赖性。ADAM17在PQ诱导的A549细胞中过表达,可能参与了百草枯诱导的肺纤维化过程。