Project description:The loss of muscle size, strength and quality with ageing, is a major determinant of morbidity and mortality in the elderly. The regulatory pathways that impact on the muscle phenotype include the translational regulation maintained by microRNAs (miRNA). Yet the miRNAs that are expressed in human skeletal muscle and whose expression levels correlate to muscle size, strength and quality are unknown. Here we used next-generation sequencing to characterise the expression profile of miRNAs in the m. vastus lateralis obtained by biopsy from middle-aged males (n=48; 50.0±4.3 years). Isokinetic strength testing and mid-thigh computed tomography was undertaken for muscle phenotype analysis. miR-486-5p accounted for 21% of the total miR sequence reads, with miR-10b-5p, miR-133a-3p, and miR-22-3p accounting for a further 15%, 12% and 10% respectively. Isokinetic knee extension strength and muscle cross-sectional area were positively correlated with miR-100-5p, miR-99b-5p and miR-191-5p expression. Whilst muscle attenuation, reflective of myofiber lipid content was negatively correlated to let-7f-5p, miR-30d-5p and miR-125b-5p expression. In-silico analysis implicates miRNAs related to strength and muscle size in the regulation of mammalian target of rapamycin, whist miRNAs related to muscle attenuation may have potential roles controlling the transforming growth factor- β/SMAD3 pathway which regulated fibrosis, adipogenesis and lipid accumulation.
Project description:This experiment was conducted to identify the mitochondrial protein changes in the presence and absence of LONP1 in skeletal muscle. The following abstract from the submitted manuscript describes the major findings of this work.Disuse-associated loss of muscle LONP1 impairs mitochondrial quality and causes reduced skeletal muscle mass and strength. Zhisheng Xu, Tingting Fu, Qiqi Guo, Danxia Zhou, Wanping Sun, Zheng Zhou, Lin Liu, Liwei Xiao, Yujing Yin, Yuhuan Jia, Xin Pan, Lei Fang, Min-sheng Zhu, Wenyong Fei, Bin Lu and Zhenji Gan. Mitochondrial proteolysis is an evolutionarily conserved quality control mechanism to maintain proper mitochondrial integrity and function. However, the physiological relevance of stress-induced impaired mitochondrial protein quality remains unclear. Here, we demonstrate that LONP1, a major mitochondrial protease resides in the matrix, plays a critical role in controlling mitochondrial quality as well as skeletal muscle mass and strength in response to muscle disuse. In humans and mice, disuse-related muscle loss is associated with decreased mitochondrial LONP1 protein. Skeletal muscle-specific ablation of LONP1 in mice resulted in impaired mitochondrial protein turnover, leading to mitochondrial dysfunction. This caused reduced muscle fiber size and strength. Mechanistically, aberrant accumulation of mitochondrial-retained protein in muscle upon loss of LONP1 induces the activation of autophagy-lysosome degradation program of muscle loss. Overexpressing a mitochondrial-retained mutant ornithine transcarbamylase (ΔOTC), a known protein degraded by LONP1, in skeletal muscle induces mitochondrial dysfunction, autophagy activation, and cause muscle loss and weakness. Thus, these findings reveal a pivotal role of LONP1-dependent mitochondrial protein quality-control in safeguarding mitochondrial function and preserving skeletal muscle mass and strength, and unravel an intriguing link between mitochondrial protein quality and muscle mass maintenance during muscle disuse.
Project description:<p>The NHGRI Next Generation Mendelian Genetics project uses exome resequencing to identify variants in unsolved Mendelian diseases.</p> <p>Samples were collected from a single, multi-generational family with the same phenotype of exaggerated muscular development (muscular hypertrophy) and strength characterized by reduced fat pad thickness under the skin. All family members deny "body building" activities, and are so far negative for known gene mutation that have been identified as associated with excessive muscle development. All family members have examples of demonstrating extraordinary strength occurring both in childhood and old age. No negative associated phenotype traits with the muscle hypertrophy phenotype have been identified.</p>
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:We combined an experimental microbiome of 11 bacterial strains isolated from the gut of native Caenorhabditis elegans. C. elegans were maintained on the experimental microbiome, Escherichia coli OP50 (control food source), or OP50 supplemented with cell-free media (CFM) from the experimental microbiome. For each of the three feeding conditions, RNA-seq was performed for wildtype (N2) worms or transgenic worms expressing amyloid beta 1-42 in their body wall muscle (GMC101).
Project description:Aging is associated with declining immunity and inflammation as well as alterations in the gut microbiome with a decrease of beneficial microbes and increase in pathogenic ones. The aim of this study was to investigate aging associated gut microbiome in relation to immunologic and metabolic profile in a non-human primate (NHP) model. 12 old (age>18 years) and 4 young (age 3-6 years) Rhesus macaques were included in this study. Immune cell subsets were characterized in PBMC by flow cytometry and plasma cytokines levels were determined by bead based multiplex cytokine analysis. Stool samples were collected by ileal loop and investigated for microbiome analysis by shotgun metagenomics. Serum, gut microbial lysate and microbe-free fecal extract were subjected to metabolomic analysis by mass-spectrometry. Our results showed that the old animals exhibited higher inflammatory biomarkers in plasma and lower CD4 T cells with altered distribution of naïve and memory T cell maturation subsets. The gut microbiome in old animals had higher abundance of Archaeal and Proteobacterial species and lower Firmicutes than the young. Significant enrichment of metabolites that contribute to inflammatory and cytotoxic pathways was observed in serum and feces of old animals compared to the young. We conclude that aging NHP undergo immunosenescence and age associated alterations in the gut microbiome that has a distinct metabolic profile.
Project description:<p>The NHGRI Next Generation Mendelian Genetics project uses exome resequencing to identify variants in unsolved Mendelian diseases.</p> <p>Samples were collected from a single, multi-generational family with the same phenotype of exaggerated muscular development (muscular hypertrophy) and strength characterized by reduced fat pad thickness under the skin. All family members deny "body building" activities, and are so far negative for known gene mutation that have been identified as associated with excessive muscle development. All family members have examples of demonstrating extraordinary strength occurring both in childhood and old age. No negative associated phenotype traits with the muscle hypertrophy phenotype have been identified.</p>
Project description:Age-related sarcopenia is associated with a variety of changes in skeletal muscle. These changes are interrelated with each other and associated with systemic metabolism, the details of which, however, are largely unknown. Eicosapentaenoic acid (EPA) is a promising nutrient against sarcopenia and has multifaceted effects on systemic metabolism. Although several human studies have suggested that EPA supplementation protects against sarcopenia, the causal relationship of EPA supplementation and an increase of muscle strength has poor evidence in vivo. We demonstrated that aging skeletal muscle in male mice shows lower grip strength and fiber type changes, both of which can be inhibited by EPA supplementation irrespective of muscle mass alteration. We hypothesized that the aging process in skeletal muscle can be intervened by the administration of EPA, via transcriptomic changes in skeletal muscle. This analysis revealed fast-to-slow fiber type transition in aging muscle, which was partially inhibited by EPA.