Project description:Androgens have a strong effect against skeletal muscles to increase muscle mass and strength. However, a molecular mechanism of AR action on muscle strength is not clear. To identify the target genes of AR in skeletal muscle, we generated myofiber specific ARKO using HSA-Cre and AR flox mice (cARKO). Nine-week-old female control and cARKO mice were treated with or without DHT for 4 weeks. After euthenization, gastrocunemius muscle were collected and total RNA were extracted.
Project description:The goal of this study was to identify changes in muscle gene expression that may contribute to loss of adaptability of old muscle. Muscle atrophy was induced in young adult (6-month) and old (32-month) male Brown Norway/F344 rats by two weeks of hind limb suspension (HS) and soleus muscles were analyzed by cDNA microarrays. We conclude that a cold shock response may be part of a compensatory mechanism in muscles undergoing atrophy to preserve remaining muscle mass and that RBM3 may be a therapeutic target to prevent muscle loss.
Project description:As a consequence of impaired glucose or fatty acid metabolism, bioenergetic stress in skeletal muscles may trigger myopathy and rhabdomyolysis. Genetic mutations causing loss of function of the LPIN1 gene frequently lead to severe rhabdomyolysis bouts in children, though the metabolic alterations and possible therapeutic interventions remain elusive. Here, we show that lipin1 deficiency in mouse skeletal muscles is sufficient to trigger myopathy. Strikingly, muscle fibers display strong accumulation of both neutral and phospholipids. The metabolic lipid imbalance can be traced to an altered fatty acid synthesis and fatty acid oxidation, accompanied by a defect in acyl chain elongation and desaturation. As an underlying cause, we reveal a severe sarcoplasmic reticulum (SR) stress, leading to the activation of the lipogenic SREBP1c/SREBP2 factors, the accumulation of the Fgf21 cytokine, and alterations of SR-mitochondria morphology. Importantly, pharmacological treatments with the chaperone TUDCA and the fatty acid oxidation activator bezafibrate improve muscle histology and strength of lipin1 mutants. Our data reveal that SR stress and alterations in SR-mitochondria contacts are contributing factors and potential intervention targets of the myopathy associated with lipin1 deficiency.
Project description:We explore whether a low-energy diet intervention for Metabolic dysfunction-associated steatohepatitis (MASH) improves liver disease by means of modulating the gut microbiome. 16 individuals were given a low-energy diet (880 kcal, consisting of bars, soups, and shakes) for 12 weeks, followed by a stepped re-introduction to whole for an additional 12 weeks. Stool samples were obtained at 0, 12, and 24 weeks for microbiome analysis. Fecal microbiome were measured using 16S rRNA gene sequencing. Positive control (Zymo DNA standard D6305) and negative control (PBS extraction) were included in the sequencing. We found that low-energy diet improved MASH disease without lasting alterations to the gut microbiome.
Project description:Pofut1 is an essential gene that glycosylates proteins containing EGF-like repeats, including Notch Receptors (NotchRs). Work in mice and in Drosophila has shown that O-fucosylation by Pofut1 is required for NotchR ligands to bind to and activate NotchRs. As such, Pofut1 deletion in skeletal myofibers allows for an analysis of potential functions and molecular changes of Pofut1 in skeletal muscle that derive from its expression in skeletal myofibers. In this study we compared gene expression profiles between quadriceps muscles in mice where Protein O-fucosyltransferase 1 (Pofut1) was deleted specifically in skeletal myofibers via use of a human skeletal alpha actin Cre transgene (Scre) and a loxP flanked Pofut1 gene (SCreFF) and mice which bore the only the Scre transgene but did not have floxed Pofut1 alleles (SCre++). Muscles were dissected from two month-old mice. We have found that SCreFF mice develop reduced muscle size and strength with age. These changes are analogous to sarcopenic changes that normally occur in aged muscles, where Pofut1 expression is also reduced. These phenotypes begin at and beyond 3 months and are very significant by 6 months of age. The goal of this study was to capture molecular changes that precede the reductions in muscle size and strength, some of which were validated by qRT-PCR.