Distinct effect of exercise modes on mood-related behavior in mice.

Exercise can afford several benefits to combat mood disorders in both rodents and humans. Engagement in various physical activities upregulates levels of neurotrophic factors in several brain regions and improves mental health. However, the type of exercise that regulates mood and the underlying mechanisms in the brain remain elusive. Herein, we performed two distinct types of exercise and RNA sequencing analyses to investigate the effect of exercise on mood-related behaviors and explain the distinct patterns of gene expression. Specifically, resistance exercise exhibited reduced immobility time in the forced swim test when compared with both no exercise and treadmill exercise (in the aerobic training [AT] group). Interestingly, anxiety-like behaviors in the open field and nest-building tests were ameliorated in the AT group when compared with those in the control group; however, this was not observed in the RT group. To elucidate the mechanism underlying these different behavioral changes caused by distinct exercise types, we examined the shift in the gene expression pattern in the hippocampus, a brain region that plays a critical role in regulating mood. We discovered that 38 and 40 genes were altered in the AT and RT groups, respectively, compared with the control group. Both exercises regulated 16 common genes. Compared with the control group, mitogen-activated protein kinase (MAPK) was enriched in the AT group and phosphatidylinositol-3-kinase (PI3K)/AKT and neurotrophin signaling pathways were enriched in the RT group, as determined by bioinformatics pathway analysis. PCR results revealed that Cebpß expression was increased in AT group, and Dcx expression was upregulated in both groups. Our findings indicate that different exercise types may exert substantially distinct effects on mood-like behaviors. Accordingly, appropriate types of exercise can be undertaken based on the mood disorder to be regulated.

Muscle fiber type-dependence effect of exercise on genomic networks in aged mice models.

Skeletal muscles are made up of various muscle fiber type including slow and fast-twitch fibers. Because each muscle fiber has its own physiological characteristics, the effects of aging and exercise vary depending on the type of muscle fiber. We used bioinformatics screening techniques such as differentially expressed gene analysis, gene ontology analysis and gene set enrichment analysis, to try to understand the genetic differences between muscle fiber types. The experiment and gene expression profiling in this study used the soleus (SOL, slow-twitch muscle) and gastrocnemius (GAS, fast-twitch muscle). According to our findings, fatty acid metabolism is significantly up-regulated in SOL compared to GAS, whereas the glucose metabolism pathway is significantly down-regulated in SOL compared to GAS. Furthermore, apoptosis and myogenesis patterns differ between SOL and GAS. SOL did not show differences in apoptosis due to the aging effect, but apoptosis in GAS was significantly up-regulated with age. Apoptosis in GAS of old groups is significantly reduced after 4 weeks of aerobic exercise, but no such finding was found in SOL. In terms of myogenesis, exercise intervention up-regulated this process in GAS of old groups but not in SOL. Taken together, muscle fiber type significantly interacts with aging and exercise. Despite the importance of the interaction between these factors, large-scale gene expression data has rarely been studied. We hope to contribute to a better understanding of the relationship between muscle fiber type, aging and exercise at the molecular level.

Association between serum alanine aminotransferase level and obesity indices in Korean adolescents.

PURPOSE: To analyze the correlation between serum alanine aminotransferase (ALT) and obesity indices including body mass index (BMI), body fat percentage (BFP), total fat mass (FM), truncal fat mass (TFM), waist circumference (WC), and waist-to-height ratio (WHtR) in Korean adolescents. METHODS: This was a cross-sectional study based on data derived from the 2010-2011 Korean National Health and Nutrition Examination Surveys (KNHANES). Subjects were Korean adolescents aged 10-18 years (871 total; 475 boys and 396 girls) who participated in KNHANES. RESULTS: In both sexes, BMI, FM, TFM, WC, and WHtR were higher when ALT levels were in the 4th quartile. In boys, there was a significant positive correlation between ALT level and BMI, BFP, FM, TFM, WC, and WHtR (r=0.55, P<0.0001 for BMI; r=0.52, P<0.0001 for BFP; r=0.58, P<0.0001 for FM; r=0.61, P<0.0001 for TFM; and r=0.56, P<0.0001 for WC; r=0.62, P<0.0001 for WHtR), and the correlation coefficient was higher than that in girls. CONCLUSION: Our results suggest a significant positive association between serum ALT level and obesity indices in male adolescents.

Single-molecule FRET study of SNARE-mediated membrane fusion.

Membrane fusion is one of the most important cellular processes by which two initially distinct lipid bilayers merge their hydrophobic cores, resulting in one interconnected structure. Proteins, called SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor), play a central role in the fusion process that is also regulated by several accessory proteins. In order to study the SNARE-mediated membrane fusion, the in vitro protein reconstitution assay involving ensemble FRET (fluorescence resonance energy transfer) has been used over a decade. In this mini-review, we describe several single-molecule-based FRET approaches that have been applied to this field to overcome the shortage of the bulk assay in terms of protein and fusion dynamics.