title: Skeletal muscle PGC-1α is required for maintaining an acute LPS-induced TNFα response.
abstract: Many lifestyle-related diseases are associated with low-grade inflammation and peroxisome proliferator activated receptor γ coactivator (PGC)-1α has been suggested to be protective against low-grade inflammation. However, whether these anti-inflammatory properties affect acute inflammation is not known. The aim of the present study was therefore to investigate the role of muscle PGC-1α in acute inflammation. Quadriceps muscles were removed from 10-week old whole body PGC-1α knockout (KO), muscle specific PGC-1α KO (MKO) and muscle-specific PGC-1α overexpression mice (TG), 2 hours after an intraperitoneal injection of either 0.8 µg LPS/g body weight or saline. Basal TNFα mRNA content was lower in skeletal muscle of whole body PGC-1α KO mice and in accordance TG mice showed increased TNFα mRNA and protein level relative to WT, indicating a possible PGC-1α mediated regulation of TNFα. Basal p65 phosphorylation was increased in TG mice possibly explaining the elevated TNFα expression in these mice. Systemically, TG mice had reduced basal plasma TNFα levels compared with WT suggesting a protective effect against systemic low-grade inflammation in these animals. While TG mice reached similar TNFα levels as WT and showed more marked induction in plasma TNFα than WT after LPS injection, MKO PGC-1α mice had a reduced plasma TNFα and skeletal muscle TNFα mRNA response to LPS. In conclusion, the present findings suggest that PGC-1α enhances basal TNFα expression in skeletal muscle and indicate that PGC-1α does not exert anti-inflammatory effects during acute inflammation. Lack of skeletal muscle PGC-1α seems however to impair the acute TNFα response, which may reflect a phenotype more susceptible to infections as also observed in type 2 diabetes patients.
authors.affiliation: Centre of Inflammation and Metabolism and Copenhagen Muscle Research Centre, Department of Biology, University of Copenhagen, Copenhagen, Denmark. jolesen@bio.ku.dk
authors.forename: Jesper
authors.initials: J
authors.lastname: Olesen
authors.forename: Signe
authors.initials: S
authors.lastname: Larsson
authors.forename: Ninna
authors.initials: N
authors.lastname: Iversen
authors.forename: Simi
authors.initials: S
authors.lastname: Yousafzai
authors.forename: Ylva
authors.initials: Y
authors.lastname: Hellsten
authors.forename: Henriette
authors.initials: H
authors.lastname: Pilegaard
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D005260:Female; D007249:Inflammation; D016753:Interleukin-10 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000737:chemistry*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D018482:Muscle, Skeletal / Q000378:metabolism; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010641:Phenotype; D010766:Phosphorylation; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha / Q000097:blood / Q000378:metabolism*
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10