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NF‐κB activation in hindlimb muscles from adult and old mice at rest and following contractile activity (LB814)
Author(s) -
Pollock Natalie,
Vasilaki Aphrodite,
Lightfoot Adam,
Jackson Malcolm,
McArdle Anne
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.lb814
Subject(s) - hindlimb , isometric exercise , skeletal muscle , luciferase , chemistry , nf κb , contraction (grammar) , nfkb1 , endocrinology , staining , in vivo , medicine , transcription factor , biology , signal transduction , pathology , biochemistry , transfection , microbiology and biotechnology , gene
Skeletal muscle adapts following contractions by increases in reactive oxygen species (ROS) leading to the detection of activation of redox‐responsive transcription factors (TFs) such as nuclear factor kappa B (NF‐κB) by electrophoresis mobility shift assay (EMSA). This TF activation is reduced in muscles from old mice and humans 1,2 . Additional studies from our laboratory have demonstrated that NF‐κB binding activity of quiescent muscles from old wild‐type (WT) mice was significantly increased compared with adult WT mice 1 . However, the significance of these findings to changes in transcriptional processes is unclear due to the ex‐vivo nature of EMSA analyses. This study used NF‐κB1 luciferase reporter mice to determine the transcriptional effect of this NF‐κB activation in hindlimb muscles from adult and old mice at rest or following an isometric contraction protocol 1 using immunofluorescence antibody staining of luciferase in transverse frozen sections of tibialis anterior (TA) muscles. Muscles were also examined for evidence of changes in the expression of cytokines known to be under the transcriptional control of NF‐κB. Luciferase staining was observed in all muscle sections with a patchwork distribution between fibres, showing as more intense overall staining in the quiescent muscles from old compared with adult mice. Immediately following the contraction protocol, the luciferase staining was increased in muscles from adult NF‐κB1 mice. In contrast, no increase was seen in the muscles from old mice following contractions compared with quiescent muscle from old mice. The chronic activation of NF‐κB was associated with increased muscle mRNA levels of a number of cytokines. These data confirm previous EMSA observations and suggest that the chronic activation of NF‐κB in muscle from old mice is associated with the generation of a pro‐inflammatory environment and this may restrict the ability in muscles of old mice to further adapt following contractile activity. Grant Funding Source : Supported by BBSRC and NIA/NIH (AG‐020591)