Degradation of brown adipocyte purine nucleotides regulates uncoupling protein 1 activity

作者：Fromme Tobias; Kleigrewe Karin; Dunkel Andreas; Retzler Angelika; Li Yongguo; Maurer Stefanie; Fischer Natascha; Diezko Rolf; Kanzleiter Timo; Hirschberg Verena; Hofmann Thomas; Klingenspor Martin

来源：Molecular Metabolism, 2018, 8: 77-85.

DOI：10.1016/j.molmet.2017.12.010

• Purine nucleotides
• Uncoupling protein 1
• Brown adipose tissue
• Non-shivering thermogenesis
• HILIC-MS/MS
• Guanosine mono-phosphate reductase

Objective: Non-shivering thermogenesis in mammalian brown adipose tissue depends on thermogenic uncoupling protein 1. Its activity is triggered by free fatty acids while purine nucleotides mediate inhibition. During activation, it is thought that free fatty acids overcome purine-ediated inhibition. We measured the cellular concentration and the release of purine nucleotide metabolites to uncover a possible role of purine nucleotide degradation in uncoupling protein 1 activation.
Methods: With mass spectrometry, purine nucleotide metabolites were quantified in cellular homogenates and supernatants of cultured primary brown adipocytes. We also determined oxygen consumption in response to a beta-adrenergic agonist.
Results: Upon adrenergic activation, brown adipocytes decreased the intracellular concentration of inhibitory nucleotides (ATP, ADP, GTP and GDP) and released the respective degradation products. At the same time, an increase in cellular calcium occurred. None of these phenomena occurred in white adipocytes or myotubes. The brown adipocyte expression of enzymes implicated in purine metabolic remodeling is altered upon cold exposure. Pharmacological and genetic interference of purine metabolism altered uncoupling protein 1 mediated uncoupled respiration.
Conclusion: Adrenergic stimulation of brown adipocytes lowers the intracellular concentration of purine nucleotides, thereby contributing to uncoupling protein 1 activation.

• 出版日期2018-2