• Role of the Aryl Hydrocarbon Receptor (Ahr) in Skeletal Muscle

      Bowles, Jessica; Lambert, Andrea; Dukes, Amy; Mendhe, Bharati; Department of Biological Sciences (2016-03)
      The AhR is a ligand-activated transcription factor known to mediate the negative effects of environmental contaminants such as dioxin. Inactivation of AhR in skeletal muscle appears to be a response to both resistance exercise training and endurance exercise training, whereas activation of the receptor impairs tissue regeneration in zebrafish. AhR is also a receptor for kynurenine, an oxidized metabolite of the aromatic amino acid tryptophan. We have found that while tryptophan can preserve lean mass and stimulate muscle-derived IGF-1 in the setting of dietary protein deficiency, kynurenine decreases both muscle mass and IGF-1. Aside from these few studies, very little is known about the role of AhR in muscle wasting in catabolic settings such as aging or disease, or how it mediates the response to exercise. We have identified expression of the AhR in skeletal muscle using immunostaining and gene expression (PCR) of mouse hindlimb muscles (tibialis anterior). We are currently working to determine whether AhR expression levels change with age, or differ between males and females. The ultimate goal of this research is to develop novel therapeutic approaches, perhaps targeting AhR, to prevent muscle loss with aging and disuse. Funding Source: National Institute on Aging