Shoichiro Asayama

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Liver sinusoidal endothelial cells (SECs) possess unique receptors that recognize and internalize hyaluronic acid (HA). To develop a system for targeting foreign DNA to SECs, comb-type polycations having HA side chains were prepared by coupling HA to poly(L-lysine) (PLL). The HA-grafted-PLL copolymer (PLL-g-HA) thus formed was mixed with DNA in 154 mM NaCl(More)
The complex between manganese (Mn) porphyrins and catalase-poly(ethylene glycol) (PEG) conjugates has been designed for the protective effect against hepatic ischemia/reperfusion injury in vivo. The resulting Mn-porphyrin/catalase-PEG complex with dual enzymatic activity of superoxide dismutase (SOD) and catalase enhanced the blood circulation. The spin(More)
A new design of antioxidant, consisting of manganese (Mn) porphyrin and signal peptide for mitochondrial targeting, is reported. The resulting Mn-porphyrin-oligopeptide conjugate exhibited significant superoxide dismutase (SOD) activity and decomposed peroxynitrite (ONOO-). The new antioxidant caused the swelling of isolated mitochondria. By using the(More)
Poly(L-histidine) (PLH) with dimethylimidazole groups has been synthesized as a pH-sensitive polypeptide to control the stability of its small interfering RNA (siRNA) polyion complexes for RNA interference (RNAi). The resulting methylated PLH (PLH-Me) was water-soluble despite deprotonation of the imidazole groups at physiological pH, as determined by(More)
Carboxymethyl poly( l-histidine) (CM-PLH) as a new pH-sensitive polypeptide has enhanced polyplex gene delivery. Agarose gel retardation assay and zeta potential measurement proved that the anionic CM-PLH at physiological pH coated the PEI/DNA binary complexes. The resulting CM-PLH/PEI/DNA ternary complexes showed the gene expression value 300 times higher(More)
We prepared an anticancer drug based on a pH-sensitive liposome retaining Fe-porphyrin as an SOD mimic. The liposomes contained cationic/anionic lipid combinations and were composed of Fe-porphyrin, 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine, dimethylditetradecylammonium bromide, sodium oleate, and Tween-80. The Fe-porphyrin was released from the(More)
Mice lacking manganese-superoxide dismutase (Mn-SOD) activity exhibit typical pathology of dilated cardiomyopathy (DCM). In the present study, the structure-activity relationship between the water-soluble manganese (Mn) porphyrin with SOD activity and the in vivo pharmaceutical effect on DCM is reported. The Mn-SOD-deficient mice were treated with(More)
Metalloporphyrin-carbohydrate conjugates have been synthesized as superoxide dismutase (SOD) mimics with cellular recognition. To synthesize the conjugates, aliphatic primary amino groups for conjugation were introduced, with the cationic pyridyl groups for the SOD activity of porphyrin preserved. The reductive amination between introduced amino groups and(More)
We have synthesized a new water-soluble cationic Mn-porphyrin with catalytic activity for both superoxide dismutation and peroxynitrite decomposition. The resulting Mn-porphyrin also showed higher stability for reactive oxygen species such as hydrogen peroxide and lower cytotoxicity, when compared with a control normal Mn-porphyrin. Furthermore, the new(More)
A new design of antioxidant, the complex between manganese (Mn) porphyrins and catalase-poly(ethylene glycol) (PEG) conjugates, is reported. Gel filtration chromatography and a Langmuir-type adsorption isotherm proved that the catalase-PEG conjugate formed the complex with the Mn-porphyrin. The resulting complex exhibited significant superoxide dismutase(More)