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

Resistance Exercise Training-Induced Muscle Hypertrophy Was Associated with Reduction of Inflammatory Markers in Elderly Women

Aging is associated with low-grade inflammation. The benefits of regular exercise for the elderly are well established, whereas less is known about the impact of low-intensity resistance exercise on low-grade inflammation in the elderly. Twenty-one elderly women (mean age ± SD, 85.0 ± 4.5 years) participated in 12 weeks of resistance exercise training. Muscle thickness and circulating levels of C-reactive protein (CRP), serum amyloid A (SAA), heat shock protein (HSP)70, tumor necrosis factor (TNF)-α, interleukin (IL)-1, IL-6, monocyte chemotactic protein (MCP-1), insulin, insulin-like growth factor (IGF)-I, and vascular endothelial growth factor (VEGF) were measured before and after the exercise training. Training reduced the circulating levels of CRP, SAA (P < .05), HSP70, IGF-I, and insulin (P < .01). The training-induced reductions in CRP and TNF-α were significantly (P < .01, P < .05) associated with increased muscle thickness (r = −0.61, r = −0.54), respectively. None of the results were significant after applying a Bonferroni correction. Resistance training may assist in maintaining or improving muscle volume and reducing low-grade inflammation

Photoprecursor approach as an effective means for preparing multilayer organic semiconducting thin films by solution processes

[プレスリリース]「重ね塗り」で有機薄膜太陽電池を高性能化～光を当てると固まる材料使い、有効性を実証～プラスチック上にも作製可能 （2014/11/19）The vertical composition profile of active layer has a major effect on the performance of organic photovoltaic devices (OPVs). While stepwise deposition of different materials is a conceptually straightforward method for controlled preparation of multi-component active layers, it is practically challenging for solution processes because of dissolution of the lower layer. Herein, we overcome this difficulty by employing the photoprecursor approach, in which a soluble photoprecursor is solution-deposited then photoconverted in situ to a poorly soluble organic semiconductor. This approach enables solution-processing of the p-i-n triple-layer architecture that has been suggested to be effective in obtaining efficient OPVs. We show that, when 2,6-dithienylanthracene and a fullerene derivative PC71BM are used as donor and acceptor, respectively, the best p-i-n OPV affords a higher photovoltaic efficiency than the corresponding p-n device by 24% and bulk-heterojunction device by 67%. The photoprecursor approach is also applied to preparation of three-component p-i-n films containing another donor 2,6-bis(59-(2-ethylhexyl)-(2,29-bithiophen)-5-yl)anthracene in the i-layer to provide a nearly doubled efficiency as compared to the original two-component p-i-n system. These results indicate that the present approach can serve as an effective means for controlled preparation of well-performing multi-component active layers in OPVs and relatedorganic electronic devices

Cross-conjugated isothianaphthene quinoids: a versatile strategy for controlling electronic structures

The elucidation of new structure–property relationships in π-conjugated molecules bearing quinoidal moieties is of relevance because of their use in organic electronics applications and their traditional assimilation as models of doped conducting polymers. Quinoidal oligothiophenes are ground state electronic hybrids between closed-shell Kekulé quinoidal and open-shell aromatic diradicaloid forms. The prominent contribution of the diradical character in longer oligomers beyond thiophene 4-mers results in a low stability, thereby limiting the ability to tune their properties. Thus, the control of these quinoidal/aromatic contributions is an important prerequisite to develop long quinoidal oligothiophenes. To address this problem, a series of quinoidal pentathiophenes with benzene-annelated isothianaphthene units were designed and successfully synthesized as stable structures. Combined molecular spectroscopies and theoretical modelling indicated that cross-conjugation appears upon the introduction of multiple benzene-annelated units, and that the number and position of the benzene-annelated units have a significant influence on the quinoidal/aromatic/cross-conjugated electronic structures. The newly developed quinoidal pentathiophenes functioned as organic semiconducting materials in transistor and near infrared phototransistor devices. This study demonstrates that modification of the cross-conjugated quinoidal structure is a promising strategy for fine-tuning electronic structures in π-extended quinoidal systems, which could help us to understand unique π-electronic features and to develop novel organic electronic materials.This work was supported by JSPS KAKENHI (20H02814, 20K21224, 20H05841, 20KK0123, 19K15505, 20H04639, 20K15352, 21K05213, 20H00379, 20H05833, and 20K15261), CREST (J205101030), NEDO (21500248-0), and “Dynamic Alliance for Open Innovation Bridging Human, Environmental and Materials” from The Ministry of Education, Culture, Sports, Science and Technology, Japan. We are grateful to Prof. Toshihiro Ohnishi for helpful discussion. The authors thank the Spanish Ministry of Science, Innovation and Universities MCIU and MINECO/FEDER of the Spanish Government (project PGC2018-098533-B-100), the Ministry of Science and Technology of the Spanish Government (project RED2018-102626-T) and the Junta de Andalucía, Spain (UMA18FEDERJA057). We also thank the Research Central Services (SCAI) of the University of Málaga. // Funding for open access charge: Universidad de Málag

Impact of substituents on the performance of small-molecule semiconductors in organic photovoltaic devices via regulating morphology

Recent years have witnessed a rapid development of organic photovoltaic devices (OPVs). The significant improvement in power conversion efficiency is due to not only the discovery of new π-conjugated frameworks, but also careful substituent engineering to achieve optimal morphology in bulk-heterojunction active layers. Indeed, all aspects of the light-to-electricity conversion in OPVs, such as light absorption, exciton diffusion, and charge-carrier transport, are influenced by the morphological characteristics of active layers. The importance of active-layer morphology on the performance of OPVs has made substituent engineering an increasingly important part of OPV semiconductor design. Herein, we overview recent prominent examples of substituent engineering, focusing on flexible substituents that regulate morphology, rather than the molecular electronic structure, of small-molecule organic semiconductors