Effect of a 9-week exercise training regimen on expression of developmental genes related to growth-dependent fat expansion in juvenile rats

Abstract

This study examined the association between changes in mRNA expression of development‐related genes including those of the homeobox (Hox) family and growth‐dependent increases in inguinal, mesenteric, and epididymal white adipose tissue (WAT) at 4, 6, 10, and 14 weeks of age in rats. We also examined the effects of a 9‐week exercise training regimen starting at 5 weeks of age on the mRNA levels of the genes of interest. HoxC8, HoxC9, Gpc4, Bmpr1a, Pparγ, Pgc1α, Adrb3, Hsl, leptin, and adiponectin in each type of WAT – except HoxA5, Gpc4, and Pgc1α in epididymal – showed a positive association between WAT weights and WAT mRNA levels; however, the slope of the regression lines exhibited fat depot‐specific differences. HoxA5 showed no significant association, and Gpc4 and Pgc1α showed a negative association in epididymal WAT. After exercise training, the mean HoxA5, HoxC8, HoxC9, HoxC10, Gpc4, Pparγ, and Pgc1α mRNA levels in inguinal WAT were outliers on the regression line between mean mRNA level and WAT weight in control rats – that is, mean HoxA5 and Pgc1α mRNA level was higher, whereas HoxC8, HoxC9, HoxC10, Gpc4, and Ppar levels were lower in exercise‐trained rats than in same‐age controls. Pparγγ and adiponectin levels were upregulated in epididymal WAT, while HoxA5 was downregulated, but HoxC9, Gpc4, Pparγ, and adiponectin levels were upregulated in mesenteric WAT. These results suggest that some of the developmental genes tested may have fat depot‐specific roles in the growth‐dependent expansion of WAT, and that Hox genes that are activated in response to exercise training also vary among different WAT types.

DNA methylation across the genome in aged human skeletal muscle tissue and muscle-derived cells: the role of HOX genes and physical activity

“…Counterintuitively to our data, previously HOXC10 upregulation has been associated with satellite cell activation in skeletal muscle in response to Roux-en-Y gastric bypass (RYGB) surgery 74 , as well as being a marker for hindlimb specific satellite cells. Interestingly, there was lower expression of HOXC10 observed in exercised rats 75 , which is perhaps more intuitive with the data provided here, where aged cells demonstrated an increase. However, HOXC10 requires more experimentation to define its mechanistic role in aging skeletal muscle with HOXC10 with physical exercise being discussed below.…”

DNA methylation across the genome in aged human skeletal muscle tissue and stem cells: The role of HOX genes and physical activity

“…Counterintuitively to our data, previously HOXC10 upregulation has been associated with satellite cell activation in skeletal muscle in response to Roux-en-Y gastric bypass (RYGB) surgery 74 , as well as being a marker for hindlimb specific satellite cells. Interestingly, there was lower expression of HOXC10 observed in exercised rats 75 , which is perhaps more intuitive with the data provided here, where aged cells demonstrated an increase. However, HOXC10 requires more experimentation to define its mechanistic role in aging skeletal muscle, with HOXC10 and physical exercise being discussed below.…”

Effect of Exercise on Fatty Acid Metabolism and Adipokine Secretion in Adipose Tissue

“…Adiponectin is an insulin-sensitizing hormone that enhances FA oxidation in the muscles and downregulates the synthesis of lipids and glucose in the liver (Swierczynski and Sledzinski, 2012). The evidence from both human and animal studies analyzing the effects of exercise on serum adiponectin level is inconclusive; chronic exercise was either shown to increase the serum concentration or expression in AT of this adipokine or did not affect it at all (Kato et al, 2018; Lehnig and Stanford, 2018). Available data imply that the release of adiponectin from human AT may depend on exercise intensity (Görgens et al, 2015).…”