一种用于以单细胞分辨率绘制钠分布图的 DNA 纳米器件。
A DNA nanodevice for mapping sodium at single-organelle resolution.
机构信息
Department of Chemistry, The University of Chicago, Chicago, IL, USA.
Neuroscience Institute, The University of Chicago, Chicago, IL, USA.
出版信息
Nat Biotechnol. 2024 Jul;42(7):1075-1083. doi: 10.1038/s41587-023-01950-1. Epub 2023 Sep 21.
Cellular sodium ion (Na) homeostasis is integral to organism physiology. Our current understanding of Na homeostasis is largely limited to Na transport at the plasma membrane. Organelles may also contribute to Na homeostasis; however, the direction of Na flow across organelle membranes is unknown because organellar Na cannot be imaged. Here we report a pH-independent, organelle-targetable, ratiometric probe that reports lumenal Na. It is a DNA nanodevice containing a Na-sensitive fluorophore, a reference dye and an organelle-targeting domain. By measuring Na at single endosome resolution in mammalian cells and Caenorhabditis elegans, we discovered that lumenal Na levels in each stage of the endolysosomal pathway exceed cytosolic levels and decrease as endosomes mature. Further, we find that lysosomal Na levels in nematodes are modulated by the Na/H exchanger NHX-5 in response to salt stress. The ability to image subcellular Na will unveil mechanisms of Na homeostasis at an increased level of cellular detail.
细胞钠离子（Na）稳态是机体生理学的重要组成部分。我们目前对 Na 稳态的理解主要局限于质膜上的 Na 转运。细胞器也可能有助于 Na 稳态；然而，由于不能对细胞器内的 Na 进行成像，因此尚不清楚细胞器膜上 Na 流动的方向。在这里，我们报告了一种 pH 独立的、细胞器靶向的、比率型探针，可报告腔室 Na。它是一种 DNA 纳米器件，包含 Na 敏感荧光团、参比染料和细胞器靶向结构域。通过在哺乳动物细胞和秀丽隐杆线虫中单内体分辨率测量 Na，我们发现内体溶酶体途径中每个阶段的腔室内 Na 水平均超过胞质水平，并随着内体成熟而降低。此外，我们发现线虫中的溶酶体 Na 水平可被 Na/H 交换器 NHX-5 调节，以响应盐胁迫。对亚细胞 Na 进行成像的能力将在更高的细胞细节水平上揭示 Na 稳态的机制。
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