No abstract

This investigation demonstrates a strong dependence of the magnetism of CeO 2 nanoparticles on the concentration of oxygen vacancies. A strong magnetic signal is over for a narrow range (0.1 < Ce 3+ /Ce < 0.2) of Ce 3+ concentrations in the nanoparticles. Previous studies have determined that most of the vacancies are at the surface of the particle and, given particles of size 3−10 nm, the strong magnetic signal corresponds to an even narrower range of Ce 3+ content at the surface (0.40 < Ce 3+ surface /Ce surface < 0.45). X-ray magnetic circular dichroism (XMCD) measurement reveals that electrons in Ce bear magnetic moments while oxygen atoms do not respond magnetically indicating that the bounded magnetic polarons are more important to magnetism than is oxygen-mediated exchange.

Statins, 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors, have been found to provide protective effects against several bacterial infectious diseases. Although the use of statins has been shown to enhance antimicrobial treated Helicobacter pylori eradication and reduce H. pylori-mediated inflammation, the mechanisms underlying these effects remain unclear. In this study, in vitro and ex vivo macrophage models were established to investigate the molecular pathways involved in statin-mediated inhibition of H. pylori-induced inflammation. Our study showed that statin treatment resulted in a dose-dependent decrease in intracellular H. pylori burden in both RAW264.7 macrophage cells and murine peritoneal exudate macrophages (PEMs). Furthermore, statin yielded enhanced early endosome maturation and subsequent activation of the autophagy pathway, which promotes lysosomal fusion resulting in degradation of sequestered bacteria, and in turn attenuates interleukin (IL)-1β production. These results indicate that statin not only reduces cellular cholesterol but also decreases the H. pylori burden in macrophages by promoting autophagy, consequently alleviating H. pylori-induced inflammation.

Cytolethal distending toxin (CDT), a genotoxin produced by Campylobacter jejuni, is composed of three subunits: CdtA, CdtB, and CdtC. CdtB is a DNase that causes DNA double-strand breaks (DSB) in the nucleus resulting in cell cycle arrest at the G2/M stage and apoptosis. CdtA and CdtC bind to cholesterol-rich microdomains on the cytoplasmic membrane, a process required for the delivery of CdtB to cells. Although a unique motif associated with cholesterol-binding activity has been identified in other pathogens, the mechanism underlying the interaction between the CdtA and CdtC subunits and membrane cholesterol remains unclear. Also, the processes of cell uptake and delivery of CdtB in host cells and the translocation of CdtB into the nucleus are only partially understood. In this review, we focus on the underlying relationship among CDT, membrane cholesterol, and the intracellular trafficking pathway as a unique mechanism for C. jejuni-induced pathogenesis. Moreover, we discuss the clinical aspects of a possible therapeutic application of CDT in cancer therapy. Understanding the molecular mechanism of CDT-host interactions may provide insights into novel strategies to control C. jejuni infection and the development of potential clinical applications of CDT.