Project description:To investigate the RNA differences in muscle with and without constitutive AHR activation. AAV9 was used to express either a green fluorescent protein (control) or mutant AHR protein that exhibits constitutive transcriptional activity
Project description:To investigate the RNA differences in skeletal muscle in muscle-specific AHR (aryl hydrocarbon receptor) knockout mice and their AHR-floxed littermate controls (wildtype) following a 16-week chronic cigarette smoke exposure intervention
Project description:Metabolic rewiring is a well-established feature of muscle cells and a hallmark of cancer. In isocitrate dehydrogenase 1 and 2 mutant tumors, increased production of the oncometabolite D-2-hydroxyglutarate (D2-HG) is associated with myopathy. The connection between metabolic changes and proteomic remodeling in skeletal muscle remains poorly understood. We demonstrate that D2-HG impairs NAD+ redox homeostasis in myocytes, causing activation of autophagy via de-acetylation of microtubule-associated protein 1 light chain 3-II (LC3-II) by the nuclear deacetylase Sirt1. We integrated multi-omics data from mice treated with D2-HG and demonstrate that autophagy activation leads to skeletal muscle atrophy and sex-dependent metabolic and proteomic remodeling. We also characterized protein and metabolite interactions linking energy-substrate metabolism with chromatin organization and autophagy regulation. Collectively, our multi-omics approach exposes mechanisms by which the oncometabolite D2-HG induces metabolic and proteomic remodeling in skeletal muscle, and provides a conceptual framework for identifying potential therapeutic targets in cachexia.
Project description:Occupational and environmental exposure to polycyclic aromatic hydrocarbons (PAHs) has been suggested to provoke inflammatory and/or allergic disorders including asthma, rhinitis and dermatitis. The molecular mechanisms of this PAH-mediated inflammation remain to be clarified. Previous studies implied the involvement of PAHs as irritants and allergens, with the reactive oxygen species generated from the oxygenated PAHs believed to be an exacerbating factor. As well, the possibility exists that PAHs contribute to the pathogenesis through activation of aryl-hydrocarbon receptor (AhR)-mediated transcription, since PAHs are potent inducers of the AhR. To address this point, we generated transgenic mouse lines expressing the constitutive active form of the AhR in keratinocytes. In these lines of mice, the AhR activity was constitutively enhanced in the absence of ligands, so that any other direct effects of PAHs and their metabolites could be ignored. At birth, these transgenic mice were normal, but severe skin lesions with itching developed postnatally. The skin lesions were accompanied by inflammation and immunological imbalance and resembled typical atopic dermatitis. Our present study demonstrates that constitutive activation of the AhR pathway causes inflammatory skin lesions and suggests a new mechanism for the exacerbation of inflammatory diseases following exposure to occupational and environmental xenobiotics. Keywords: transcriptional activation
Project description:Utilizing glycerol intramuscular injections in M. musculus provide a models of skeletal muscle damage followed by skeletal muscle regeneration. In particular, glycerol-induced muscle injury triggers accute activation of skeletal muscle stem cells, called satellite cells. However, aging dramatically impairs the regenerative capacity of satellite cells. We characterized genome-wide expression profiles of young and old satellite cells in the non-proliferative and activated state, freshly isolated to non-injured or damaged muscles, respectively. Our goal was to uncover new regulatory signaling specific to satellite cells entry into the activation and myogenic program that are affected with age. Satellite cells were isolated in either quiescent / non-proliferative or activated state from uninjured or 3 days after glycerol-induced injury of tibialis anterior, gastrocnemius and quadriceps, respectively. Young (2-4 months old) and old (20-24 months old) wildtype C57BL/6J male were used, with five to six biological replicates per group.
Project description:Utilizing glycerol intramuscular injections in M. musculus provide a models of skeletal muscle damage followed by skeletal muscle regeneration. In particular, glycerol-induced muscle injury triggers accute activation of skeletal muscle stem cells, called satellite cells. However, aging dramatically impairs the regenerative capacity of satellite cells. We characterized genome-wide expression profiles of young and old satellite cells in the non-proliferative and activated state, freshly isolated to non-injured or damaged muscles, respectively. Our goal was to uncover new regulatory signaling specific to satellite cells entry into the activation and myogenic program that are affected with age.