<特集> リスク「コミュニケーション」への遠い道 ~コロナ禍中の実践から

departmental bulletin pape

Small Heat Shock Protein αB-Crystallin Controls Shape and Adhesion of Glioma and Myoblast Cells in the Absence of Stress

<div><p>Cell shape and adhesion and their proper controls are fundamental for all biological systems. Mesenchymal cells migrate at an average rate of 6 to 60 μm/hr, depending on the extracellular matrix environment and cell signaling. Myotubes, fully differentiated muscle cells, are specialized for power-generation and therefore lose motility. Cell spreading and stabilities of focal adhesion are regulated by the critical protein vinculin from immature myoblast to mature costamere of differentiated myotubes where myofibril Z-band linked to sarcolemma. The Z-band is constituted from microtubules, intermediate filaments, cell adhesion molecules and other adapter proteins that communicate with the outer environment. Mesenchymal cells, including myoblast cells, convert actomyosin contraction forces to tension through mechano-responsive adhesion assembly complexes as Z-band equivalents. There is growing evidence that microtubule dynamics are involved in the generation of contractile forces; however, the roles of microtubules in cell adhesion dynamics are not well determined. Here, we show for the first time that αB-crystallin, a molecular chaperon for tubulin/microtubules, is involved in cell shape determination. Moreover, knockdown of this molecule caused myoblasts and glioma cells to lose their ability for adhesion as they tended to behave like migratory cells. Surprisingly, αB-crystallin knockdown in both C6 glial cells and L6 myoblast permitted cells to migrate more rapidly (2.7 times faster for C6 and 1.3 times faster for L6 cells) than dermal fibroblast. On the other hand, overexpression of αB-crystallin in cells led to an immortal phenotype because of persistent adhesion. Position of matured focal adhesion as visualized by vinculin immuno-staining, stress fiber direction, length, and density were clearly αB-crystallin dependent. These results indicate that the small HSP αB-crystallin has important roles for cell adhesion, and thus microtubule dynamics are necessary for persistent adhesion.</p></div

Japanese citizens' behavioral changes and preparedness against COVID-19: An online survey during the early phase of the pandemic.

The Japanese government instituted countermeasures against COVID-19, a pneumonia caused by the new coronavirus, in January 2020. Seeking "people's behavioral changes," in which the government called on the public to take precautionary measures or exercise self-restraint, was one of the important strategies. The purpose of this study is to investigate how and from when Japanese citizens have changed their precautionary behavior under circumstances in which the government has only requested their cooperation. This study uses micro data from a cross-sectional survey conducted on an online platform of an online research company, based on quota sampling that is representative of the Japanese population. By the end of March 2020, a total of 11,342 respondents, aged from 20 to 64 years, were recruited. About 85 percent reported practising the social distancing measures recommended by the government including more females than males and more older than younger participants. Frequent handwashing is conducted by 86 percent of all participants, 92 percent of female, and 87.9 percent of over-40 participants. The most important event influencing these precautionary actions was the infection aboard the Diamond Princess cruise ship, which occurred in early February 2020 (23 percent). Information from the central and local governments, received by 60 percent of the participants, was deemed trustworthy by 50 percent. However, the results also showed that about 20 percent of the participants were reluctant to implement proper prevention measures. The statistical analysis indicated that the typical characteristics of those people were male, younger (under 30 years old), unmarried, from lower-income households, a drinking or smoking habit, and a higher extraversion score. To prevent the spread of infection in Japan, it is imperative to address these individuals and encourage their behavioural changes using various means to reach and influence them

Cell morphology and αB-crystallin level.

<p>(A) Characteristic cell morphology is specific to αB-crystallin level as revealed by inhibitory antibody injection and (B) injection of purified bovine lens protein αB-crystallin into wild-type, αB-crystallin-overexpressing and knockdown C6 cells. Asterisk indicates P value of <0.05.</p

Impact of Rac1 on morphology of αB-crystallin-overexpressing and knockdown cells.

<p>C6 cells were transfected with EGFP-Rac1 (wild-type), EGFP-constitutively active Rac1 (V12), and EGFP-dominant-negative Rac1 (N17), and fluorescence images were taken after 12 h. αB-crystallin knockdown C6 cells that expressed Rac 1^V12 showed enlarged peripheral ruffles at both ends of spindle-shaped cells. On the other hand, complete loss of lengthened pseudopods was observed in Rac1^N17 transfected cells (A). Area change (B) and shape index (C) of EGFP-Rac1, Rac1^V12, Rac1^N17 expressed wild-type, αB-crystallin overexpressed, and knockdown C6 cells. ** = P<0.01, *P = 0.05, n = 50.</p

αB-crystallin-overexpressing cells and knockdown C6 cells: shape change after Nocodazole treatment.

<p>Images from just after the drug addition (final 10 μg/mL; 0 min, left panel) and after 90 min (right panel) (A). Bar = 40 μm. Cell area (B) and Shape index (C) change of C6 cells after Nocodazole treatment. N = 20.</p