Effects of rosiglitazone and high fat diet on lipase/esterase expression in adipose tissue

A number of intracellular lipase/esterase have been reported in adipose tissue either by functional assays of activity or through proteomic analysis. In the current work, we have studied the relative expression level of 12 members of the lipase/esterase family that are found in white adipose tissue. We found that the relative mRNA levels of ATGL and HSL are the most abundant, being 2-3 fold greater than TGH or ADPN; whereas other intracellular neutral lipase/esterases were expressed at substantially lower levels. High fat feeding did not alter the mRNA expression levels of most lipase/esterases, but did reduce CGI-58 and WBSCR21. Likewise, rosiglitazone treatment did not alter the mRNA expression levels of most lipase/esterases, but did increase ATGL, TGH, CGI-58 and WBSCR21, while reducing ADPN. WAT from HSL-/- mice showed no compensatory increase in any lipase/esterases, rather mRNA levels of most lipase/esterases were reduced. In contrast, BAT from HSL-/- mice showed an increase in ATGL expression, as well as a decrease in ES-1, APEH and WBSCR21. Analysis of the immunoreactive protein levels of some of the lipases confirmed the results seen with mRNA. In conclusion, these data highlight the complexity of the regulation of the expression of intracellular neutral lipase/esterases involved in lipolysis.