Hyperlipidemia, characterized by high serum
lipids, is a risk factor for
cardiovascular disease. Recent studies have identified an important role for
celastrol, a
proteasome inhibitor isolated from Tripterygium wilfordii Hook. F., in
obesity-related metabolic disorders. However, the exact influences of
celastrol on lipid metabolism remain largely unknown.
Celastrol inhibited the terminal differentiation of 3T3-L1 adipocytes and decreased the levels of
triglycerides in wild-type mice. Lipidomics analysis revealed that
celastrol increased the metabolism of
lysophosphatidylcholines (LPCs),
phosphatidylcholines (PCs),
sphingomyelins (SMs), and
phosphatidylethanolamines (PEs). Further,
celastrol reversed the
tyloxapol-induced
hyperlipidemia induced associated with increased plasma LPCs, PCs, SMs, and
ceramides (CMs). Among these
lipids, LPC(16:0), LPC(18:1), PC(22:2/15:0), and SM(d18:1/22:0) were also decreased by
celastrol in cultured 3T3-L1 adipocytes, mice, and
tyloxapol-treated mice. The mRNAs encoded by hepatic genes associated with
lipid synthesis and catabolism, including Lpcat1, Pld1, Smpd3, and Sptc2, were altered in
tyloxapol-induced
hyperlipidemia, and significantly recovered by
celastrol treatment. The effect of
celastrol on lipid metabolism was significantly reduced in Fxr-null mice, resulting in decreased Cers6 and Acer2 mRNAs compared to wild-type mice. These results establish that FXR was responsible in part for the effects of
celastrol in controlling lipid metabolism and contributing to the recovery of aberrant lipid metabolism in
obesity-related metabolic disorders.