| First Author | Vilà-Brau A | Year | 2011 |
| Journal | J Biol Chem | Volume | 286 |
| Issue | 23 | Pages | 20423-30 |
| PubMed ID | 21502324 | Mgi Jnum | J:173493 |
| Mgi Id | MGI:5014147 | Doi | 10.1074/jbc.M111.235044 |
| Citation | Vila-Brau A, et al. (2011) Human HMGCS2 Regulates Mitochondrial Fatty Acid Oxidation and FGF21 Expression in HepG2 Cell Line. J Biol Chem 286(23):20423-30 |
| abstractText | HMGCS2 (hydroxymethylglutaryl CoA synthase 2), the gene that regulates ketone body production, is barely expressed in cultured cell lines. In this study, we restored HMGCS2 expression and activity in HepG2 cells, thus showing that the wild type enzyme can induce fatty acid beta-oxidation (FAO) and ketogenesis, whereas a catalytically inactive mutant C166A did not generate either process. Peroxisome proliferator-activated receptor (PPAR) alpha expression also induces fatty acid beta-oxidation and endogenous HMGCS2 expression. Interestingly, PPARalpha-mediated induction was abolished when HMGCS2 expression was down-regulated by RNAi. These results indicate that HMGCS2 expression is both sufficient and necessary to the control of fatty acid oxidation in these cells. Next, we examined the expression pattern of several PPARalpha target genes in this now 'ketogenic' HepG2 cell line. FGF21 (fibroblast growth factor 21) expression was specifically induced by HMGCS2 activity or by the inclusion of the oxidized form of ketone bodies (acetoacetate) in the culture medium. This effect was blunted by SirT1 (sirtuin 1) RNAi, so we propose a SirT1-dependent mechanism for FGF21 induction by acetoacetate. These data suggest a novel feed-forward mechanism by which HMGCS2 could regulate adaptive metabolic responses during fasting. This mechanism could be physiologically relevant, because fasting-mediated induction of liver FGF21 was dependent on SirT1 activity in vivo. |
