Transcriptomic responses of hypothalamus to acute exercise in type 2 diabetic Goto-Kakizaki rats

Glycolipid metabolism and liver transcriptomic analysis of the therapeutic effects of pressed degreased walnut meal extracts on type 2 diabetes mellitus rats

Walnut meal (WM) is rich in polyphenols which exhibit multiple therapeutic effects. The purpose of this study was to investigate the therapeutic effects of walnut meal extracts (WMP) on glycolipid metabolism and liver transcriptomics in T2DM rats. A T2DM rat model was established by using a high-fat diet combined with streptozotocin. A 5-week WMP therapy showed the effects of decreasing water intake, excretion, fasting blood glucose, fasting insulin, and insulin resistance, increasing β-cell function and insulin sensitivity index; meanwhile regulating dysfunctional lipid metabolism and reducing inflammation; improving body weight, oral glucose tolerance test and insulin sensitivity; and increasing the activities of SOD and CAT while decreasing the MDA levels in the liver and serum of T2DM rats. Moreover, 10 key differentially expressed genes were identified by RNA-seq, including Gck, RT1-Ba, Fasn, Slc13a3, Cd74, Jun, Cyp4a1, Myh7b, Plin3, and Got1, and they were highly potentially related to glycolipid metabolism. Our results suggested that WMP exhibited the anti-diabetic effect and could regulate glycolipid metabolism in T2DM rats. This finding might assist in identifying potential therapeutic targets for T2DM prevention and intervention.

Transcriptional profile in rat muscle: down-regulation networks in acute strenuous exercise

Background

Physical exercise is a health promotion factor regulating gene expression and causing changes in phenotype, varying according to exercise type and intensity. Acute strenuous exercise in sedentary individuals appears to induce different transcriptional networks in response to stress caused by exercise. The objective of this research was to investigate the transcriptional profile of strenuous experimental exercise.

Methodology

RNA-Seq was performed with Rattus norvegicus soleus muscle, submitted to strenuous physical exercise on a treadmill with an initial velocity of 0.5 km/h and increments of 0.2 km/h at every 3 min until animal exhaustion. Twenty four hours post-physical exercise, RNA-seq protocols were performed with coverage of 30 million reads per sample, 100 pb read length, paired-end, with a list of counts totaling 12816 genes.

Results

Eighty differentially expressed genes (61 down-regulated and 19 up-regulated) were obtained. Reactome and KEGG database searches revealed the most significant pathways, for down-regulated gene set, were: PI3K-Akt signaling pathway, RAF-MAP kinase, P2Y receptors and Signaling by Erbb2. Results suggest PI3K-AKT pathway inactivation by Hbegf, Fgf1 and Fgr3 receptor regulation, leading to inhibition of cell proliferation and increased apoptosis. Cell signaling transcription networks were found in transcriptome. Results suggest some metabolic pathways which indicate the conditioning situation of strenuous exercise induced genes encoding apoptotic and autophagy factors, indicating cellular stress.

Conclusion

Down-regulated networks showed cell transduction and signaling pathways, with possible inhibition of cellular proliferation and cell degeneration. These findings reveal transitory and dynamic process in cell signaling transcription networks in skeletal muscle after acute strenuous exercise.

Effects of metabolic state on the regulation of melanocortin circuits

Dysfunction in neurophysiological systems that regulate food intake and metabolism are at least partly responsible for obesity and related comorbidities. An important component of this process is the hypothalamic melanocortin system, where an imbalance can result in severe obesity and deficits in glucose metabolism. Exercise offers many health benefits related to cardiovascular improvements, hunger control, and blood glucose homeostasis. However, the molecular mechanism underlying the exercise-induced improvements to the melanocortin system remain undefined. Here, we review the role of the melanocortin system to sense hormonal, nutrient, and neuronal signals of energy status. This information is then relayed onto secondary neurons in order to regulate physiological parameters, which promote proper energy and glucose balance. We also provide an overview on the effects of physical exercise to induce biophysical changes in the melanocortin circuit which may regulate food intake, glucose metabolism and improve overall metabolic health.