Stress responsive miR-23a attenuates skeletal muscle atrophy by targeting MAFbx /atrogin-1

Muscle atrophy occurs in many pathological states and results primarily from accelerated protein degradation by the ubiquitin-proteasome pathway. We used dexamethasone to induce muscle wasting and investigated the role of a microRNA (miRNA) in the control of muscle-specific E3 ubiquitin ligase MAFbx/atrogin-1. Here we show that miR-23a suppresses MAFbx/atrogin-1 translation by binding to 3'UTR of the mRNA. Furthermore, ectopic expression of miR-23a is sufficient to protect myocytes from atrophy in vitro and in vivo in response to dexamethasone treatment, and heat stress-induced miR-23a protects muscle from dexamethasone-induced muscle atrophy. Our surprising discovery of the physiological role of miR-23a in preventing the atrophy program should lay the basis not only for further understanding of the mechanisms of muscle wasting in diverse diseases, but also for developing novel therapies for these debilitating conditions

Hydrostatic pressure prevents chondrocyte differentiation through heterochromatin remodeling

Articular cartilage protects and lubricates joints for smooth motion and transmission of loads. Owing to its high water content, chondrocytes within the cartilage are exposed to high levels of hydrostatic pressure, which has been shown to promote chondrocyte identity through unknown mechanisms. Here, we investigate the effects of hydrostatic pressure on chondrocyte state and behavior, and discover that application of hydrostatic pressure promotes chondrocyte quiescence and prevents maturation towards the hyperlrophic state. Mechanistically, hydrostatic pressure reduces the amount of trimethylated H3K9 (K3K9me3)-marked constitutive heterochromatin and concomitantly increases H3K27me3-marked facultative heterochromatin. Reduced levels of H3K9me3 attenuates expression of pre-hypertrophic genes, replication and transcription, thereby reducing replicative stress. Conversely, promoting replicative stress by inhibition of topoisomerase II decreases Sox9 expression, suggesting that it enhances chondrocyte maturation. Our results reveal how hydrostatic pressure triggers chromatin remodeling to impact cell fate and function. This article has an associated First Person interview with the first author of the paper.Peer reviewe

Visual Influence of Additive Color Mixture in reconstructed Hologram Images using He-Cd Laser and Dichroic Mirrors

A blue white beam of commercially available He-Cd laser can be divided into the three primary color beams of light, i. e., R/G/B beam components using a set of dichroic mirrors. The dichroic mirror is widely used for color TV cameras to separate the visual image into its three primary color components. In this study, an influence of additive color mixture in two types of reconstructed hologram images is checked through the optical experiments using the He-Cd laser and dichroic mirrors. The visual appearances and deteriorations of reconstructed color images owing to the cross-talk called overlapped or ghost image are discussed as for the optical Fresnel hologram and computer generated FTH (Fourier Transform Hologram)

カンジョウニンシキ ニ オケル ガゾウジョウホウ ト オンセイジョウホウ ノ カンケイ

This study examined the relationship between image (visual) and sound (auditory) information for emotion recognition. In the experiment, participants were asked to categorize the character in the movie scene into the six basic expressions of emotion with sound and without sound information. Chi-Square(X^2) test showed the count of catesgries were varied (p<0.05) between with and without sound information. We assumed the distance between the emotion categories from the experimental results obtained with and without sound condition. Multidimensional scaling (MDS) reveals that the distance between "Surprise and Fear" is small as well as "Anger and Disgust". We consider that auditory information is important to discriminate these expressions of emotion. And we found "Sadness" was plotted at almost equal distance from the "Surprise and Fear", "Anger and Disgust" and "Happiness"

Assessment of the Inner Surface Microstructure of Decellularized Cortical Bone by a Scanning Electron Microscope

The microstructural changes of bones, which form a hierarchy of skeletal tissue, vary, depending on their condition, and are affected by the behaviors of bone cells. The purpose of this study is to assess the microstructural changes in the inner femoral surface of Sprague Dawley rats according to the conditions using a scanning electron microscope. Microstructural differences on the endocortical surface were observed in the characteristics of osteocytic canaliculi, bone fibers, and surface roughness, showing a rougher surface in old adults and an osteoporosis model by quantitative comparison. These results could be helpful for developing a basic understanding of the microstructural changes that occur on the bone surface under various conditions