Skeletal muscle deiodinase type 2 regulation during illness in mice

We have previously shown that skeletal muscle deiodinase type 2 (D2) mRNA (listed as Dio2 in MGI Database) is up-regulated in an animal model of acute illness. However, human Studies on the expression Of muscle D2 during illness report conflicting data. Therefore, we evaluated the expression of skeletal Muscle D2 and D2-regulating factors in two mouse models OF illness that differ in timing and severity of illness: 1) turpentine-iuduced inflammation, and 2) Streptococcus pneumoniae infection. During tupentine-induced inflammation, D2 mRNA and activity increased compared to pair-fed controls, most prominently at day I and 2, whereas after S. pneumoniae infection D2 mRNA decreased. We evaluated the association of D2 expression with scrum thyroid hormones, (de-)ubiquitinating enzymes ubiquitin-specific peptidase 33 and WD repeat and SOCS box-containing 1 (Wsb1) cytokine expression and activation of inflammatory pathways and cAMP pathways During chronic inflammation the increased muscle D2 expression is associated with the activation of the cAMP pathway. The normalization of D2 5 days after turpentine injection coincides with increased Wsb1 and tumor necrosis factor a expression. Muscle iuterleukiu-1 beta (II1b) expression correlated with decreased D2 mRNA expression after S. pneumoniae infection. In conclusion, Muscle 02 expression is differentially regulated during illness, probably related to differences in the inflammatory response and type of pathology. D2 mRNA and activity increases in skeletal muscle during the acute phase Of chronic inflammation compared to pair-fed controls probably due to activation of the cAMP pathway. In contrast, muscle D2 mRNA decreases 48h after 1 severe bacterial infection, which is associated with local II1b mRNA expression and might also be due to diminished food-intake. Journal of Endocrinology (2009) 203, 263-270