Development of an X-ray HARP–FEA detector system for high-throughput protein crystallography

A new detector system for protein crystallography based on an X-ray HARP–FEA is presented

Neurocytotoxic effects of iron-ions on the developing brain measured in vivo using medaka (Oryzias latipes), a vertebrate model

Purpose: Exposure to heavy-ion radiation is considered a critical health risk on long-term space missions. The developing central nervous system (CNS) is a highly radiosensitive tissue; however, the biological effects of heavy-ion radiation, which are greater than those of low-linear energy transfer (LET) radiation, are not well studied, especially in vivo in intact organisms. Here, we examined the effects of iron-ions on the developing CNS using vertebrate organism, fish embryos of medaka (Oryzias latipes)

Relationship Between the Physicochemical Properties of Lipid Nanoparticles and the Quality of siRNA Delivery to Liver Cells

While a variety of short interfering RNA (siRNA) delivery compounds have been developed, a deep understanding of the key parameters that determine the quality of siRNA delivery are not known with certainty. Therefore, an understanding of the factors required for the efficient, selective, and safe delivery of siRNA is a great challenge for successful siRNA delivery. Herein, we report on the development of two pH-sensitive cationic lipids and their use in examining the impact of the acid dissociation constant (pK(a)) value, lipase sensitivity and the size of lipid nanoparticles on the biodistribution, and efficiency and cell specificity of gene silencing in the liver. An increase in the pK(a) value resulted in a significant change in the intrahepatic localization of siRNA and gene-silencing efficiency in hepatocytes and liver sinusoidal endothelial cells (LSECs). The sensitivity of the pH-sensitive cationic lipid to lipases was a major factor in achieving hepatocyte-specific gene silencing. Increasing the particle size can improve the LSEC specificity of gene silencing. As a consequence, we succeeded in developing both a highly efficient, hepatocyte-specific formulation, and the most efficacious LSEC-targeted formulation reported to date. These findings will facilitate the development of more sophisticated siRNA delivery systems

Topology of Surface Ligands on Liposomes: Characterization Based on the Terms, Incorporation Ratio, Surface Anchor Density, and Reaction Yield

The surface topology of ligands on liposomes is an important factor in active targeting in drug delivery systems. Accurately evaluating the density of anchors and bioactive functional ligands on a liposomal surface is critical for ensuring the efficient delivery of liposomes. For evaluating surface ligand density, it is necessary to clarify that on the ligand-modified liposomal surfaces, some anchors are attached to ligands but some are not. To distinguish between these situations, a key parameter, surface anchor density, was introduced to specify amount of total anchors on the liposomal surface. Second, the parameter reaction yield was introduced to identify the amount of ligand-attached anchors among total anchors, since the conjugation efficiency is not always the same nor 100%. Combining these independent parameters, we derived: incorporation ratio=surface anchor densityxreaction yield. The term incorporation ratio defines the surface ligand density. Since the surface anchor density represents the density of polyethylene glycol (PEG) on the surfaces in most cases, it also determines liposomal function. It is possible to accurately characterize various PEG and ligand densities and to define the surface topologies. In conclusion, this quantitative methodology can standardize the liposome preparation process and qualify the modified liposomal surfaces

A pH-sensitive cationic lipid facilitates the delivery of liposomal siRNA and gene silencing activity in vitro and in vivo

Modification of liposomal siRNA carriers with polyethylene glycol, i.e., PEGylation, is a generally accepted strategy for achieving in vivo stability and delivery to tumor tissue. However, PEGylation significantly inhibits both cellular uptake and the endosomal escape process of the carriers. In a previous study, we reported on the development of a multifunctional envelope-type nano device (MEND) for siRNA delivery and peptide-based functional devices for overcoming the limitations and succeeded in the efficient delivery of siRNA to tumors. In this study, we synthesized a pH-sensitive cationic lipid, YSK05, to overcome the limitations. The YSK05-MEND had a higher ability for endosomal escape than other MENDs containing conventional cationic lipids. The PEGylated YSK05-MEND induced efficient gene silencing and overcame the limitations followed by optimization of the lipid composition. Furthermore, the intratumoral administration of the YSK05-MEND resulted in a more efficient gene silencing compared with MENDs containing conventional cationic lipids. Collectively, these data confirm that YSK05 facilitates the endosomal escape of the MEND and thereby enhances the efficacy of siRNA delivery into cytosol and gene silencing

A lipid nanoparticle for the efficient delivery of siRNA to dendritic cells

Applying small interfering RNA (siRNA) to dendritic cell (DC) based therapy represents a potential candidate for cancer immunotherapy. However, delivering siRNA to DCs is a challenging issue for non-viral vectors. To date, only viral vectors have achieved efficient gene silencing in DCs. We report herein that a novel cationic lipid, YSK12-C4, when loaded in a nanoparticle with siRNA (YSK12-C4 multifunctional envelope type nano device [YSK12-MEND]), greatly facilitated gene silencing in mouse DCs. The use of the YSK12-MEND resulted in a gene silencing efficiency in excess of 90%, with a median effective dose (ED50) of 1.5 nM, whereas the maximum gene silencing efficiency of Lipofectamine RNAiMAX was less than 60% and the ED50 was 25 nM. Furthermore, suppressor of cytokine signaling 1, an immune suppressive molecule in DCs, silenced in the mouse DC by the YSK12-MEND showed a drastic enhancement in cytokine production, resulting in the significant suppression of tumor growth when it was applied to DC-based therapy against a mouse lymphoma. These results clearly indicate that YSK12-MEND overcomes the obstacle associated with non-viral vectors and can be considered to be a promising non-viral vector for siRNA delivery to DCs, thus accelerating DC-based therapies with siRNA. (C) 2016 Elsevier B.V. All rights reserved