scholarly journals Allosteric regulation of thioesterase superfamily member 1 by lipid sensor domain binding fatty acids and lysophosphatidylcholine

2020 ◽  
Vol 117 (36) ◽  
pp. 22080-22089 ◽  
Author(s):  
Matthew C. Tillman ◽  
Norihiro Imai ◽  
Yue Li ◽  
Manoj Khadka ◽  
C. Denise Okafor ◽  
...  

Nonshivering thermogenesis occurs in brown adipose tissue to generate heat in response to cold ambient temperatures. Thioesterase superfamily member 1 (Them1) is transcriptionally up-regulated in brown adipose tissue upon exposure to the cold and suppresses thermogenesis in order to conserve energy reserves. It hydrolyzes long-chain fatty acyl-CoAs that are derived from lipid droplets, preventing their use as fuel for thermogenesis. In addition to its enzymatic domains, Them1 contains a C-terminal StAR-related lipid transfer (START) domain with unknown ligand or function. By complementary biophysical approaches, we show that the START domain binds to long-chain fatty acids, products of Them1’s enzymatic reaction, as well as lysophosphatidylcholine (LPC), lipids shown to activate thermogenesis in brown adipocytes. Certain fatty acids stabilize the START domain and allosterically enhance Them1 catalysis of acyl-CoA, whereas 18:1 LPC destabilizes and inhibits activity, which we verify in cell culture. Additionally, we demonstrate that the START domain functions to localize Them1 near lipid droplets. These findings define the role of the START domain as a lipid sensor that allosterically regulates Them1 activity and spatially localizes it in proximity to the lipid droplet.

2020 ◽  
Author(s):  
Matthew C. Tillman ◽  
Norihiro Imai ◽  
Yue Li ◽  
Manoj Khadka ◽  
C. Denise Okafor ◽  
...  

AbstractNon-shivering thermogenesis occurs in brown adipose tissue to generate heat in response to cold temperatures. Thioesterase superfamily member 1 (Them1) is transcriptionally upregulated in brown adipose tissue upon cold exposure and suppresses thermogenesis to conserve energy reserves. Them1 hydrolyzes long-chain fatty acyl-CoAs, preventing their use as fuel for thermogenesis. Them1 contains a C-terminal StAR-related lipid transfer domain (StarD) with unknown ligand or function. By complementary biophysical approaches, we show that StarD binds to long-chain fatty acids, products of Them1’s enzymatic reaction, as well lysophosphatidylcholine (LPC), which activate thermogenesis in brown adipocytes. Certain fatty acids stabilize the StarD and allosterically enhance Them1 catalysis of acyl-CoA, whereas 18:1 LPC destabilizes and inhibits activity, which we verify in cell culture. Additionally, we demonstrate that the StarD functions to localize Them1 near lipid droplets. These findings define the role of the StarD as a lipid sensor that allosterically regulates Them1 activity and localization.


Author(s):  
Chandramohan Chitraju ◽  
Alexander Fischer ◽  
Robert V. Farese ◽  
Tobias C. Walther

SUMMARYBrown adipocytes store metabolic energy as triglycerides (TG) in multilocular lipid droplets (LDs). Fatty acids released from brown adipocyte LDs by lipolysis are thought to activate and fuel UCP1-mediated thermogenesis. Here we test this hypothesis by preventing fatty acid storage in murine brown adipocytes through brown adipose tissue (BAT)-specific deletions of the TG synthesis enzymes, DGAT1 and DGAT2 (BA-DGAT KO). Despite the absence of LDs, BA-DGAT KO mice had functional BAT and maintained euthermia during acute or chronic cold exposure. As apparent adaptations to the lack of TG, brown adipocytes of BA-DGAT KO mice appear to utilize circulating glucose and fatty acids, as well as stored glycogen to fuel thermogenesis. Moreover, BA-DGAT KO mice were resistant to diet-induced glucose intolerance, likely due to increased glucose disposal by BAT. Thus, surprisingly, TGs in BAT are dispensable for its function, in part through adaptations to utilize other fuel sources.


1995 ◽  
Vol 20 (6) ◽  
pp. 477-484 ◽  
Author(s):  
Akihiro Kuroshima ◽  
Tomie Ohno ◽  
Mitsuru Moriya ◽  
Hiroshi Ohinata ◽  
Takehiro Yahata ◽  
...  

2013 ◽  
Vol 6 (3) ◽  
pp. 121-133 ◽  
Author(s):  
Eamon P. Breen ◽  
Wayne Pilgrim ◽  
Kieran J. Clarke ◽  
Cristy Yssel ◽  
Mark Farrell ◽  
...  

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1703-1703
Author(s):  
Yang Yang ◽  
Xinyun Xu ◽  
Katie Graham ◽  
Ahmed Bettaieb ◽  
Christophe Morisseau ◽  
...  

Abstract Objectives Brown adipose tissue (BAT), responsible for energy expenditure through nonshivering thermogenesis, has emerged as a novel target for obesity treatment and prevention. Soluble epoxide hydrolase (sEH), encoded by Ephx2 gene, is a cytosolic enzyme that converts epoxy fatty acids (EpFAs) that are produced by cytochrome P-450 enzymes from polyunsaturated fatty acids into less active diols. Pharmacological inhibitors of sEH, such as trans-4-{4-[3-(4-trifluoromethoxyphenyl)-ureido] cyclohexyloxy} benzoic acid (t-TUCB), have been shown to be beneficial for chronic diseases by inhibiting the degradation of EpFAs. We have previously shown that t-TUCB dose-dependently promotes brown adipogenesis in vitro. This study investigated the therapeutic effects of t-TUCB on BAT activation in diet-induced obese mice. Methods Male C57BL6/J mice were fed a high-fat diet (60% kcal from fat) for 8 weeks followed by random assignment into either the control or t-TUCB group (n = 10 per group) to receive either the vehicle control or t-TUCB (3 mg/kg/day) via osmotic minipump delivery at the subcutaneous area near the interscapular BAT for 6 weeks. Bodyweight and food intake, glucose and insulin tolerance tests, cold tolerance tests, and indirect calorimetry were measured before the mice were euthanized for further biochemical analysis. Results sEH inhibition by t-TUCB in the obese mice did not change body weight, fat pad weight, food intake, fasting blood glucose, glucose and insulin tolerance, or cold tolerance, but significantly decreased blood triglyceride levels and increased heat production during both day and night. Moreover, t-TUCB significantly increased protein expression of brown marker gene PGC-1alpha and lipid droplet-associated protein perilipin (PLIN), but not uncoupling protein 1 (UCP1), in the interscapular BAT of diet-induced obese mice. Conclusions Our results suggest that sEH pharmacological inhibition may be beneficial for BAT activation by increasing mitochondrial biogenesis and lipolysis in the BAT. Further studies using the sEH inhibitors and/or EpFA generating diets for obesity treatment and prevention are warranted. Funding Sources The work was supported by NIH 1R15DK114790–01A1 (to L.Z.), K99DK100736 and R00DK100736 (to A.B.), R15AT008733 (to S.W.), R35 ES030443 and P42ES004699 (to B.D.H).


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