title: Association of interleukin-15 protein and interleukin-15 receptor genetic variation with resistance exercise training responses.
abstract: Interleukin-15 (IL-15) is an anabolic cytokine that is produced in skeletal muscle and directly affects muscle anabolism in animal and in vitro models. The contribution of IL-15 variability in muscle responses to 10 wk of resistance exercise training in young men and women was examined by measuring acute and chronic changes in IL-15 protein in plasma and characterizing genetic variation in the IL-15 receptor-alpha gene (IL15RA). Participants trained 3 days a week at 75% of one repetition maximum, performing three sets (6-10 repetitions) of 13 resistance exercises. Plasma IL-15 protein was significantly increased (P < 0.05) immediately after acute resistance exercise but did not change with training and was not associated with variability in muscle responses with training. A single nucleotide polymorphism in exon 7 of IL15RA was strongly associated with muscle hypertrophy and accounted for 7.1% of the variation in regression modeling. A polymorphism in exon 4 was also independently associated with muscle hypertrophy and accounted for an additional 3.5% of the variation in hypertrophy. These results suggest that IL-15 is an important mediator of muscle mass response to resistance exercise training in humans and that genetic variation in IL15RA accounts for a significant proportion of the variability in this response.
authors.affiliation: Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, PA 15260, USA. riechman@helix.hgen.pitt.edu
authors.forename: Steven E
authors.initials: SE
authors.lastname: Riechman
authors.forename: G
authors.initials: G
authors.lastname: Balasekaran
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Roth
authors.forename: Robert E
authors.initials: RE
authors.lastname: Ferrell
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D005260:Female; D014644:Genetic Variation; D006239:Haplotypes; D006801:Humans; D019409:Interleukin-15 / Q000097:blood*; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology*; D010641:Phenotype; D053647:Receptors, Interleukin-15; D015375:Receptors, Interleukin-2 / Q000235:genetics* / Q000378:metabolism; D012044:Regression Analysis; D015398:Signal Transduction / Q000502:physiology
chemical_list: C508024:IL15RA protein, human; D019409:Interleukin-15; D053647:Receptors, Interleukin-15; D015375:Receptors, Interleukin-2