Karger Gabriele, Dringen Ralf
Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, P.O. Box 330440, 28334, Bremen, Germany.
Centre for Environmental Research and Sustainable Technologies, University of Bremen, Bremen, Germany.
Neurochem Res. 2025 Aug 23;50(5):275. doi: 10.1007/s11064-025-04511-x.
Astrocytes contain a high concentration of adenosine triphosphate (ATP) that enables these cells to perform their physiological functions in brain. To investigate the mechanisms involved in astrocytic ATP restoration, the ATP content of cultured primary rat astrocytes was first depleted by a preincubation with the mitochondrial uncoupler BAM15 before extracellular substrates and their combinations were applied to foster ATP restoration. To test for the contribution of the purine salvage pathway to synthesize new adenosine monophosphate (AMP) for ATP restoration, several purine nucleosides and purine bases as well as their combinations were applied. In the absence of glucose, partial ATP restoration was found for incubations with inosine and guanosine that was lowered by forodesine, an inhibitor of purine nucleoside phosphorylase. In glucose-fed cells, the coapplication of micromolar concentrations of adenine with inosine or guanosine, but not with ribose, accelerated ATP restoration in a concentration-dependent manner. By such treatments, 80% of the initial ATP content were restored within 40 min. The supporting effects of inosine and guanosine on ATP restoration were prevented by the presence of forodesine, demonstrating the contribution of purine nucleoside phosphorylase in the ATP restoration observed. These data demonstrate that ATP-deprived astrocytes need for rapid ATP restoration - in addition to glucose as energy substrate - an adenine source and inosine or guanosine as precursor for the ribose phosphate moiety of ATP.
星形胶质细胞含有高浓度的三磷酸腺苷（ATP），这使这些细胞能够在大脑中执行其生理功能。为了研究星形胶质细胞ATP恢复所涉及的机制，首先通过与线粒体解偶联剂BAM15预孵育来耗尽原代培养大鼠星形胶质细胞的ATP含量，然后应用细胞外底物及其组合来促进ATP恢复。为了测试嘌呤补救途径对合成新的单磷酸腺苷（AMP）以恢复ATP的贡献，应用了几种嘌呤核苷和嘌呤碱及其组合。在没有葡萄糖的情况下，发现用肌苷和鸟苷孵育可部分恢复ATP，而嘌呤核苷磷酸化酶抑制剂福多司坦可降低这种恢复。在葡萄糖喂养的细胞中，微摩尔浓度的腺嘌呤与肌苷或鸟苷共同应用，但不与核糖共同应用，以浓度依赖的方式加速了ATP的恢复。通过这种处理，在40分钟内可恢复80%的初始ATP含量。福多司坦的存在阻止了肌苷和鸟苷对ATP恢复的支持作用，证明了嘌呤核苷磷酸化酶在所观察到的ATP恢复中的作用。这些数据表明，除了葡萄糖作为能量底物外，ATP缺乏的星形胶质细胞快速恢复ATP还需要腺嘌呤来源以及肌苷或鸟苷作为ATP核糖磷酸部分的前体。
