Quantitative expression patterns of peroxisome proliferator-activated receptor-beta/delta (PPARbeta/delta) protein in mice.

The expression patterns of PPARbeta/delta have been described, but the majority of these data are based on mRNA data. To date, there are no reports that have quantitatively examined the expression of PPARbeta/delta protein in mouse tissues. In the present study, a highly specific PPARbeta/delta antibody was developed, characterized, and used to examine tissue expression patterns of PPARbeta/delta. As compared to commercially available anti-PPARbeta/delta antibodies, one of six polyclonal anti-PPARbeta/delta antibodies developed was significantly more effective for immunoprecipitation of in vitro-translated PPARbeta/delta. This antibody was used for quantitative Western blot analysis using radioactive detection methods. Expression of PPARbeta/delta was highest in colon, small intestine, liver, and keratinocytes as compared to other tissues including heart, spleen, skeletal muscle, lung, brain, and thymus. Interestingly, PPARbeta/delta expression was localized in the nucleus and RXRalpha can be co-immunoprecipitated with nuclear PPARbeta/delta. Results from these studies demonstrate that PPARbeta/delta expression is highest in intestinal epithelium, liver, and keratinocytes, consistent with significant biological roles in these tissues.