Cell culture studies indicate that beta-carotene-(BC)-derived apocarotenoid signaling molecules influence the activities of nuclear receptors that regulate many aspects of adipocyte physiology. Here, we analyzed the roles of the two BC metabolizing enzymes, BCMO1 and BCDO2, for this process in mouse models. Wild-type mice converted BC into retinoids and showed reduced body adiposity (by 28%), leptinemia and adipocyte size. Genome wide microarray analysis revealed a generalized decrease of mRNA expression of peroxisome proliferator-activated receptor gamma (PPARgamma) target genes. Consistently, the expression of this key transcription factor for lipogenesis was significantly reduced both on the mRNA and protein levels. This effect of BC was absent in Bcmo1-/- mice that showed increased BCDO2 expression and gamma-10gamma-apocarotenoid production. Our study evidences an important role of BC for the control of body adiposity in mice and identifies Bcmo1 as critical molecular player for the regulation of PPARgamma activity.
Overall design
The goal of the study was to analyze the putative differential effects of BC accumulation on Bcmo1 ko mice, and BC metabolites in wt mice. Inguinal adipose tissue gene expression profile comparing adult male and female mice under control diet and beta-carotene (BC) supplemented diet during 14 weeks. 47 mice in total. 23 wild-type (11 male/12 female) and 24 bcmo1 (12 male/12 female) mice, fed on vitamin A diet (1500 IU vit A/kg diet) or vitamin A diet supplemented with BC (1500 IU vit A/kg diet +150 mg BC/kg diet) during 14 weeks.
Nutritional effects by beta-carotene versus control in lung, inguinal white adipose tissue, and liver in males and females of control wildtype mice versus BCMO/BCO1 knockout mice
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