Project description:The aim of the experiment was the analysis of key molecular changes with an unbiased, transcriptomics-based approach in a prediabetes model. Small RNA sequencing analysis was applied to explore the expression changes resulted high-fat chow (supplemented with 40% lard) diet for 21 weeks and a single low dose of streptozotocin (20 mg/kg) treatment at week 4. Long-Evans rats were used in the present study. Left ventricular samples(n=6) of both prediabetic and control groups were analyzed.
Project description:The additional therapeutic effects of regular exercise during a dietary weight loss program in people with obesity and prediabetes are unclear. We evaluated the effect of 10% weight loss, induced within ~5 months by calorie-restriction alone (Diet-ONLY, n=8) or calorie-restriction plus multi-modal exercise training (Diet+EX, n=8), on metabolic function in people with obesity and prediabetes. Whole-body (primarily muscle) and hepatic insulin sensitivity were 2-3 fold greater in the Diet+EX than the Diet-ONLY group, and were accompanied by increased muscle expression of genes involved in mitochondrial biogenesis, energy metabolism and angiogenesis in the Diet+EX group without any change in the Diet-ONLY group. There were no differences between groups in plasma branched-chain amino acids or markers of inflammation, and both interventions caused similar changes in the gut microbiome. These results demonstrate that adding regular exercise to a diet-induced weight loss program has profound metabolic benefits in people with obesity and prediabetes.
Project description:Introduction: β-adrenergic stimulation using β-agonists such as isoproterenol has been routinely used to induce cardiac fibrosis in experimental in animal models. While transcriptome changes in surgical models of cardiac fibrosis such as Transverse aortic constriction (TAC), and coronary artery ligation (CAL) are well-studied, transcriptional changes during isoproterenol induced cardiac fibrosis is not well explored. Methods: Cardiac fibrosis was induced in male C57BL6 mice by administration of isoproterenol for 4, 8 or 11 days at 50mg/kg/day dose. Temporal changes in gene expression were studied by RNA sequencing. Results: We observed a significant alteration in the transcriptome profile across the different experimental groups compared to the saline group. Isoproterenol treatment caused upregulation of genes associated with ECM organization, cell-cell contact, three-dimensional structure, and cell growth, while genes associated with fatty acid oxidation, sarcoplasmic reticulum calcium ion transport, and cardiac muscle contraction are downregulated. A number of known long non-coding RNAs (lncRNAs) and putative novel lncRNAs exhibited differential regulation. Conclusion: In conclusion, our study shows that isoproterenol administration leads to the deregulation of genes relevant to ECM deposition and cardiac contraction and serves as an excellent alternate model to the surgical models of heart failure.
Project description:Adverse cardiac remodeling contributes to the development and progression of heart failure (HF) driven, in part, by inappropriate sympathetic nervous system activation. While blockade of β-adrenergic receptors (β-AR) is a common therapeutic strategy in HF, not all patients respond necessitating elucidation of additional therapeutic approaches. Minocycline is an FDA-approved antibiotic with pleiotropic properties, independent of its antimicrobial action, and recent evidence suggests it may act by altering gene expression via changes in miRNA expression. Therefore, we hypothesized that minocycline would prevent adverse cardiac remodeling induced by the β-AR agonist isoproterenol involving relevant alterations in the miRNA-mRNA transcriptome. Male C57BL/6J mice received Iso (30 mg/kg/d, sc) or vehicle for 21 days via osmotic minipump and daily treatment with either minocycline (50 mg/kg, ip) or sterile saline. Isoproterenol infusion induced cardiac hypertrophy, with no change in cardiac function, that was prevented by minocycline. Total mRNA sequencing revealed that isoproterenol altered gene networks associated with inflammation and metabolism while activation of fibrosis was predicted by integrated miRNA-mRNA sequencing, involving miR-21, -30a, -34a, -92a, and -150, among others. Conversely, the cardiac miRNA-mRNA transcriptome predicted inhibition of fibrosis in hearts from mice treated with minocycline plus isoproterenol involving anti-fibrotic shifts in Atf3 and Itgb6 gene expression associated with upregulation of miR-194. Consistent with these gene signatures, picrosirius red staining confirmed isoproterenol-induced cardiac fibrosis and that this was prevented by minocycline. These results demonstrate the therapeutic potential of minocycline to attenuate adverse cardiac remodeling via miRNA-mRNA-dependent mechanisms, especially related to reduced cardiac fibrosis.