Publications by authors named "Mitsuhiro Hirase"

Exosomes are small (30-100 nm) membrane vesicles that serve as regulatory agents for intercellular communication in cancers. Currently, exosomes are detected by immuno-based assays with appropriate pretreatments like ultracentrifugation and are time consuming (>12 h). We present a novel pretreatment-free fluorescence-based sensing platform for intact exosomes, wherein exchangeable antibodies and fluorescent reporter molecules were aligned inside exosome-binding cavities.

View Article and Find Full Text PDF

α-Synuclein (α-Syn)-positive intracytoplasmic inclusions, known as Lewy bodies, are thought to be involved in the pathogenesis of Lewy body diseases, such as Parkinson's disease (PD). Although growing evidence suggests that cell-to-cell transmission of α-Syn is associated with the progression of PD and that extracellular α-Syn promotes formation of inclusion bodies, its precise mechanism of action in the extracellular space remains unclear. Here, as indicated by both conventional fractionation techniques and FRET-based protein-protein interaction analysis, we demonstrate that extracellular α-Syn causes expulsion of sphingosine 1-phosphate receptor subtype 1 (S1PR) from the lipid raft fractions.

View Article and Find Full Text PDF

Exosomes play a critical role in cell-to-cell communication by delivering cargo molecules to recipient cells. However, the mechanism underlying the generation of the exosomal multivesicular endosome (MVE) is one of the mysteries in the field of endosome research. Although sphingolipid metabolites such as ceramide and sphingosine 1-phosphate (S1P) are known to play important roles in MVE formation and maturation, the detailed molecular mechanisms are still unclear.

View Article and Find Full Text PDF