Data set of: "The NAD+ precursor NMN activates dSarm to trigger axon degeneration in Drosophila"

This dataset contains all experiments published in doi: 10.7554/eLife.80245 (PMID: 36476387). It contains templates of different experiments, raw and analysed data, pictures, graphs, videos, and figures. ABSTRACT: Axon degeneration contributes to the disruption of neuronal circuit function in diseased and injured nervous systems. Severed axons degenerate following the activation of an evolutionarily conserved signaling pathway, which culminates in the activation of SARM1 in mammals to execute the pathological depletion of the metabolite NAD+. SARM1 NADase activity is activated by the NAD+ precursor nicotinamide mononucleotide (NMN). In mammals, keeping NMN levels low potently preserves axons after injury. However, it remains unclear whether NMN is also a key mediator of axon degeneration and dSarm activation in flies. Here, we demonstrate that lowering NMN levels in Drosophila through the expression of a newly generated prokaryotic NMN-Deamidase (NMN-D) preserves severed axons for months and keeps them circuit-integrated for weeks. NMN-D alters the NAD+ metabolic flux by lowering NMN, while NAD+ remains unchanged in vivo. Increased NMN synthesis by the expression of mouse nicotinamide phosphoribosyltransferase (mNAMPT) leads to faster axon degeneration after injury. We also show that NMN-induced activation of dSarm mediates axon degeneration in vivo. Finally, NMN-D delays neurodegeneration caused by loss of the sole NMN-consuming and NAD+-synthesizing enzyme dNmnat. Our results reveal a critical role for NMN in neurodegeneration in the fly, which extends beyond axonal injury. The potent neuroprotection by reducing NMN levels is similar to the interference with other essential mediators of axon degeneration in Drosophila.本数据集收录了发表于DOI: 10.7554/eLife.80245（PubMed文献编号：36476387）的全部实验内容，包含各类实验模板、原始数据与分析后数据、图片、统计图、视频及科研插图。 摘要： 轴突变性会破坏病变及受损神经系统中的神经元环路功能。离断的轴突会在进化保守的信号通路激活后发生变性，该通路最终在哺乳动物体内激活SARM1，以引发代谢物烟酰胺腺嘌呤二核苷酸（NAD+）的病理性耗竭。SARM1的烟酰胺腺嘌呤二核苷酸糖苷酶（NADase）活性可由烟酰胺单核苷酸（NMN，NAD+前体）激活。在哺乳动物中，维持低水平的NMN可在损伤后有效保护轴突。然而，NMN是否也是果蝇体内轴突变性及dSarm激活的关键介质，目前仍不明确。 本研究证实，通过表达新构建的原核来源NMN脱氨酶（NMN-D）降低果蝇体内的NMN水平，可使离断轴突存活数月，并在数周内维持其环路完整性。NMN-D通过降低体内NMN水平改变NAD+代谢流，而体内NAD+水平保持不变。过表达小鼠源烟酰胺磷酸核糖转移酶（mNAMPT）以增加NMN合成，会加速损伤后轴突变性。本研究还证实，NMN介导的dSarm激活可在体内引发轴突变性。最后，NMN-D可延缓因果蝇唯一的NMN消耗型NAD+合成酶dNmnat缺失所导致的神经变性。本研究结果揭示了NMN在果蝇神经变性过程中的关键作用，这一作用并不局限于轴突损伤。通过降低NMN水平实现的强效神经保护作用，与干扰果蝇体内其他轴突变性关键介质的效果一致。