Influence of age on leptin induced skeletal muscle signalling. (May 2014)

• Record Type: Journal Article
• Authors: Guadalupe‐Grau, A.; Larsen, S.; Guerra, B.; Calbet, J. A. L.; Dela, F.; Helge, J. W.
• Is Part Of: Acta physiologica. Volume 211:Number 1(2014:May)
• Page Start: 214
• Page End: 228
• Publication Date: 2014-05
• Subjects: Physiology -- Periodicals; Physiology -- Research -- Periodicals; 612
• DOI: 10.1111/apha.12273
• Languages: English
• ISSNs: 1748-1708

Abstract

<abstract abstract-type="main" id="apha12273-abs-0001"> <title>Abstract</title> <sec id="apha12273-sec-0001" sec-type="section"> <title>Aim</title> <p>Age associated fat mass accumulation could be because of dysregulation of leptin signalling in skeletal muscle. Thus, we investigated total protein expression and phosphorylation levels of the long isoform of the leptin receptor (OB‐Rb), and leptin signalling through janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3), insulin receptor substrate 1 (IRS‐1), AMP‐activated protein kinase (AMPK) and acetyl‐coenzyme A carboxylase (ACC), combined with the leptin signalling inhibitors suppressor of cytokine signalling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) in human skeletal muscle of different age.</p> </sec> <sec id="apha12273-sec-0002" sec-type="section"> <title>Methods</title> <p>Vastus lateralis muscle biopsies were obtained from 39 men matched for BMI < 30 kg m<sup>−2</sup> and separated into three groups: 13 young (Y, 24 ± 4 years); 14 middle aged (MA, 44 ± 5 years) and 12 aged (A, 58 ± 8 years) subjects.</p> </sec> <sec id="apha12273-sec-0003" sec-type="section"> <title>Results</title> <p>Whole body fat percentage and plasma leptin were higher (<italic>P</italic> < 0.05), whereas lean mass, plasma free testosterone and total testosterone were lower (<italic>P</italic> < 0.05) in A compared to Y. Skeletal muscle OB‐Rb (170 KDa) protein expression and pTyr<sup>1141</sup>‐OB‐R170 were comparable between groups, whereas pTyr<sup>985</sup>‐OB‐R170 was lower in A compared to Y (<italic>P</italic> < 0.05). pSTAT3 levels tended (<italic>P</italic> = 0.09) to be lower (50%) in A compared to Y. In A, muscle PTP1B was greater and IRS‐1 lower than Y and MA respectively (<italic>P</italic> < 0.05). PTyr<sup>612</sup>‐IRS‐1 tended to be lower in A than in Y (<italic>P</italic> = 0.09). Suppressor of cytokine signalling 3 (SOCS3) protein expression, pJAK2, pSer<sup>1101</sup>‐IRS‐1, pAMPK<italic>α</italic> and pACC<italic>β</italic> were similar between groups.</p> </sec> <sec id="apha12273-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Age is associated with dysregulation of the leptin signalling and increased PTP1B protein expression in skeletal muscle.</p> </sec> </abstract>