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G protein-coupled receptor 81 (GPR81), a selective receptor for lactate, expresses in skeletal muscle cells, but the physiological role of GPR81 in skeletal muscle has not been fully elucidated. As it has been reported that the lactate administration induces muscle hypertrophy, the stimulation of GPR81 has been suggested to mediate muscle hypertrophy. To clarify the contribution of GPR81 activation in skeletal muscle hypertrophy, in the present study, we investigated the effect of GPR81 agonist administration on skeletal muscle mass in mice. Male C57BL/6J mice were randomly divided into control group and GPR81 agonist-administered group that received oral administration of the specific GPR81 agonist 3-Chloro-5-hydroxybenzoic acid (CHBA). In both fast-twitch plantaris and slow-twitch soleus muscles of mice, the protein expression of GPR81 was observed. Oral administration of CHBA to mice significantly increased absolute muscle weight and muscle weight relative to body weight in the two muscles. Moreover, both absolute and relative muscle protein content in the two muscles were significantly increased by CHBA administration. CHBA administration also significantly upregulated the phosphorylation level of p42/44 extracellular signal-regulated kinase-1/2 (ERK1/2) and p90 ribosomal S6 kinase (p90RSK). These observations suggest that activation of GRP81 stimulates increased the mass of two types of skeletal muscle in mice in vivo. Lactate receptor GPR81 may positively affect skeletal muscle mass through activation of ERK pathway. [ABSTRACT FROM AUTHOR]

In general, viral haemorrhagic septicaemia virus (VHSV) isolates from marine fish species in European waters (genotypes GIb, GII and GIII) are non- to low virulent in rainbow trout. However, a VHSV isolation was made in 2007 from a disease outbreak in sea farmed rainbow trout in Norway. The isolate, named NO-2007-50-385, was demonstrated to belong to GIII. This isolate has attracted attention to assess which of the viral genome/proteins might be associated with the virulence in rainbow trout. In this study, we describe the difference of virulence in rainbow trout between the NO-2007-50-385 and 4p168 isolates as representatives of virulent and non-virulent GIII isolates, respectively. Rainbow trout were bath challenged with VHSV NO-2007-50-385 for 1 and 6 h, resulting in cumulative mortalities of 5 and 35%, respectively. No mortality was observed in the rainbow trout groups immersed with the genotype III VHSV isolate 4p168 for 1 and 6 h. The viral titre in organs from fish challenged with NO-2007-50-385 for 6 h increased more rapidly than those exposed for 1 h. By in vitro studies it was demonstrated that the final titres of VHSV DK-3592B (GI), NO-2007-50-385 and 4p168 inoculated on EPC cells were very similar, whereas when inoculated on the rainbow trout cell line RTG-2 the titre of the non-virulent 4p168 isolate was 3-4 logs below the two other VHSV isolates. Based on a comparative analysis of the entire genome of the genotype III isolates, we suggest that substitutions of amino acids in positions 118-123 of the nucleo-protein are candidates for being related to virulence of VHSV GIII in rainbow trout. [ABSTRACT FROM AUTHOR]

Cyclosporine, a calcineurin inhibitor, is a potent immunosuppressive agent that acts chiefly through the inactivation of T-lymphocytes. Several clinical studies have demonstrated the effectiveness of cyclosporine for treating fibrotic lung disease, but the underlying mechanism remains elusive. We hypothesized that cyclosporine exerts direct effects against fibrogenesis of lung myofibroblasts, and aimed to elucidate the mechanism of this anti-fibrotic effect through gene-expression profiling using DNA microarray analysis. We found that cyclosporine suppressed the expression of alpha-smooth muscle actin and collagen type I in myofibroblasts that had been differentiated from a fetal human lung fibroblast cell line by induction with transforming growth factor (TGF)-β. Furthermore, microarray analysis revealed that cyclosporine down- regulated 57 genes whose expression levels were increased by TGF-β, and up-regulated 73 genes, whose expression was decreased by TGF-β. Classifying these 57 down-regulated and 73 up-regulated genes with the Database for Annotation, Visualization and Integrated Discovery (DAVID) web tool, we have identified the involvement of several functional categories, including innate immunity, cytokine interaction, growth factor, and cancer pathway. Of the identified genes, we selected three fibrosis-related genes, insulin-like growth factor binding protein 2 (IGFBP2), inhibitor of DNA binding 1 (ID1) and peroxisome proliferator-activated receptor gamma (PPARG), and validated their expression patterns by quantitative reverse transcription-polymerase chain reaction. Cyclosporine treatment decreased the expression levels of IGFBP2 and ID1, but increased PPARG expression. These results suggest that cyclosporine is a potent anti-fibrotic agent acting on myofibroblasts. Therefore, cyclosporine shows potential as a novel remedy for fibrotic lung disease. [ABSTRACT FROM AUTHOR]