Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA.
Commun Biol. 2023 Feb 20;6(1):203. doi: 10.1038/s42003-023-04562-2.
In many organisms, dietary restriction (DR) leads to lifespan extension through the activation of cell protection and pro-longevity gene expression programs. In the nematode C. elegans, the DAF-16 transcription factor is a key aging regulator that governs the Insulin/IGF-1 signaling pathway and undergoes translocation from the cytoplasm to the nucleus of cells when animals are exposed to food limitation. However, how large is the influence of DR on DAF-16 activity, and its subsequent impact on lifespan has not been quantitatively determined. In this work, we assess the endogenous activity of DAF-16 under various DR regimes by coupling CRISPR/Cas9-enabled fluorescent tagging of DAF-16 with quantitative image analysis and machine learning. Our results indicate that DR regimes induce strong endogenous DAF-16 activity, although DAF-16 is less responsive in aged individuals. DAF-16 activity is in turn a robust predictor of mean lifespan in C. elegans, accounting for 78% of its variability under DR. Analysis of tissue-specific expression aided by a machine learning tissue classifier reveals that, under DR, the largest contribution to DAF-16 nuclear intensity originates from the intestine and neurons. DR also drives DAF-16 activity in unexpected locations such as the germline and intestinal nucleoli.
在许多生物中，饮食限制（DR）通过激活细胞保护和延长寿命的基因表达程序来延长寿命。在秀丽隐杆线虫中，DAF-16 转录因子是一个关键的衰老调节剂，它控制胰岛素/ IGF-1 信号通路，并在动物暴露于食物限制时从细胞质转位到细胞的细胞核。然而，DR 对 DAF-16 活性的影响有多大，以及它对寿命的后续影响尚未被定量确定。在这项工作中，我们通过将 CRISPR/Cas9 介导的 DAF-16 荧光标记与定量图像分析和机器学习相结合，评估了各种 DR 方案下 DAF-16 的内源性活性。我们的结果表明，DR 方案诱导了强烈的内源性 DAF-16 活性，尽管 DAF-16 在老年个体中的反应性较低。DAF-16 活性反过来也是秀丽隐杆线虫平均寿命的一个强有力的预测因子，在 DR 下占其变异性的 78%。通过机器学习组织分类器进行的组织特异性表达分析表明，在 DR 下，对 DAF-16 核强度的最大贡献来自于肠道和神经元。DR 还在意想不到的部位如生殖细胞和肠道核仁中驱动 DAF-16 活性。
