Glycosphingolipid requirements for endosome-to-golgi transport of shiga toxin

Shiga toxin binds to globotriaosylceramide (Gb3) receptors on the target cell surface. To enter the cytosol, Shiga toxin is dependent on endocytic uptake, retrograde transport to the Golgi apparatus and further to the endoplasmic reticulum before translocation of the enzymatically active moiety to the cytosol. Here, we have investigated the importance of newly synthesized glycosphingolipids for the uptake and intracellular transport of Shiga toxin in HEp-2 cells. Inhibition of glycosphingolipid synthesis by treatment with either PDMP or Fumonisin B(1) for 24-48 h strongly reduced the transport of Gb3-bound Shiga toxin from endosomes to the Golgi apparatus. This was associated with a change in localization of sorting nexins 1 and 2, and accompanied by a protection against the toxin. In contrast, there was no effect on transport or toxicity of the plant toxin ricin. High-resolution mass spectrometry revealed a 2-fold reduction in Gb3 at conditions giving a 10-fold inhibition of Shiga toxin transport to the Golgi. Furthermore, mass spectrometry showed that the treatment with PDMP (DL-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol) and Fumonisin B(1) among other changes of the lipidome, affected the relative content of the different glycosphingolipid species. The largest depletion was observed for the hexosylceramide species with the N-amidated fatty acid 16:0, whereas hexosylceramide species with 24:1 were less affected. Quantitative lipid profiling with mass spectrometry demonstrated that PDMP did not influence the content of sphingomyelins, phospholipids and plasmalogens. In contrast, Fumonisin B(1) affected the amount and composition of sphingomyelin and glycolipids and altered the profiles of phospholipids and plasmalogens

Mat og måltider for aktive eldre - en studie av aktive eldres preferanser, prioriteringer og praksiser

Tilknyttede prosjekter EldreMat- Norwegian foods optimised for an ageing population (KMB

Drug-Loaded Photosensitizer-Chitosan Nanoparticles for Combinatorial Chemo- and Photodynamic-Therapy of Cancer

In this study we have developed biodegradable polymeric nanoparticles (NPs) containing the cytostatic drugs mertansine (MRT) or cabazitaxel (CBZ). The NPs are based on chitosan (CS) conjugate polymers synthesized with different amounts of the photosensitizer tetraphenylchlorin (TPC). These TPC–CS NPs have high loading capacity and strong drug retention due to π–π stacking interactions between the drugs and the aromatic photosensitizer groups of the polymers. CS polymers with 10% of the side chains containing TPC were found to be optimal in terms of drug loading capacity and NP stability. The TPC–CS NPs loaded with MRT or CBZ displayed higher cytotoxicity than the free form of these drugs in the breast cancer cell lines MDA-MB-231 and MDA-MB-468. Furthermore, light-induced photochemical activation of the NPs elicited a strong photodynamic therapy effect on these breast cancer cells. Biodistribution studies in mice showed that most of the TPC–CS NPs accumulated in liver and lungs, but they were also found to be localized in tumors derived from HCT-116 cells. These data suggest that the drug-loaded TPC–CS NPs have a potential in combinatory anticancer therapy and as contrast agents