Shinji Deguchi

Polydimethylsiloxane (PDMS) is the most commonly used silicone elastomer with a wide range of applications including microfluidics and microcontact printing. Various types of PDMS are currently available, and their bulk material properties have been extensively investigated. However, because the properties are rarely compared in a single study, it is often unclear whether the large disparity of the reported data is attributable to the difference in methodology or to their intrinsic characteristi

The structure of stress fibers, contractile actin bundles, differs between motile and non-motile cells, though the same term "stress fiber" is used to refer to the structurally as well as functionally different actin bundles. Stress fibers in non-motile cells run between separate focal adhesions, producing isometric tension due to actomyosin contraction. The stress fiber contraction is maintained through dynamic molecular exchanges between preformed and cytoplasmic components. This isometric con

Dynamic remodelling of actin stress fibres (SFs) allows non-muscle cells to adapt to applied forces such as uniaxial cell shortening. However, the mechanism underlying rapid and selective disassembly of SFs oriented in the direction of shortening remains to be elucidated. Here, we investigated how myosin crossbridge cycling induced by MgATP is associated with SF disassembly. Moderate concentrations of MgATP, or [MgATP], induced SF contraction. Meanwhile, at [MgATP] slightly higher than the physi

Actin bundles in vascular endothelial cells (ECs) play a critical role in transmitting intracellular forces between separate focal adhesion sites. However, quantitative descriptions of tension level in single actin bundles in a physiological condition are still poorly studied. Here, we evaluated magnitude of preexisting tension in a single actin bundle of ECs on the basis of measurements of its preexisting stretching strain and tensile properties. Cultured ECs expressing fluorescently-labeled ac

Human periodontal ligament-derived fibroblasts (HPLF) were grown to confluency in culture and were subjected to various combinations of neutrophils (PMNs), lipopolysaccharide (LPS) and the chemoattractant formylmethionyl-leucyl-phenylalanine (FMLP). After treatment, the cells were stained to distinguish between normal and damaged cells. The stain also allowed an estimation of PMN adherence to the HPLF monolayer. We report that FMLP, LPS or PMNs alone did not damage HPLF cells, nor did PMNs when

Epithelial to mesenchymal transition (EMT) is a fundamental biological process that occurs during development and tumorigenesis. The Rho family of GTPases (Rho-family) is a well-characterized regulator of actin cytoskeleton that gives rise to EMT-associated cell activities. Meanwhile, there are in total at least 66 different Rho-GTPase-activating proteins (Rho-GAPs), which, as an upstream regulator, inactivate specific members of the Rho-family in a cell context-dependent manner. However, molecu

Cells adapt to applied cyclic stretch (CS) to circumvent chronic activation of proinflammatory signaling. Currently, the molecular mechanism of the selective disassembly of actin stress fibers (SFs) in the stretch direction, which occurs at the early stage of the cellular response to CS, remains controversial. Here, we suggest that the mechanosensitive behavior of myosin II, a major cross-linker of SFs, primarily contributes to the directional disassembly of the actomyosin complex SFs in bovine

Intracellular stress transmission through subcellular structural components has been proposed to affect activation of localized mechano-sensing sites such as focal adhesions in adherent cells. Previous studies reported that physiological extracellular forces produced heterogeneous spatial distributions of cytoplasmic strain. However, mechanical signaling pathway involved in intracellular force transmission through basal actin stress fibers (SFs), a mechano-responsive cytoskeletal structure, rema

Cellular response to physical stretch has been extensively studied as a regulator of various physiological functions. For live cell microscopy combined with stretch experiments, cells are typically seeded on an extensible elastomer sheet. In this case, the position of the cells of interest tends to shift out of the field of view upon stretch, making real-time imaging of identical cells difficult. To circumvent this situation, here we describe a robust methodology in which these cell shifts are m

The sound source of a voice is produced by the self-excited oscillation of the vocal folds. In modal voice production, a drastic increase in transglottal pressure after vocal fold closure works as a driving force that develops self-excitation. Another type of vocal fold oscillation with less pronounced glottal closure observed in falsetto voice production has been accounted for by the mucosal wave theory. The classical theory assumes a quasi-steady flow, and the expected driving force onto the v