Single-cell monitoring of dry mass and dry mass density reveals exocytosis of cellular dry contents in mitosis.
Single-cell monitoring of dry mass and dry mass density reveals exocytosis of cellular dry contents in mitosis.
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DOI：
10.7554/elife.76664
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发表时间：
2022-05-10
期刊：
影响因子：
7.7
通讯作者：
Manalis, Scott R.
中科院分区：
文献类型：
--
作者：
Miettinen, Teemu P.;Ly, Kevin S.;Lam, Alice;Manalis, Scott R.
细胞质量和组成随细胞周期的进展而变化。我们之前的工作描述了有丝分裂过程中的浮力质量动力学（Miettinen等人，2019），但有丝分裂过程中干质量和细胞成分的变化仍不清楚。为了更好地了解有丝分裂细胞的生长和组成变化，我们开发了一种单细胞方法，用于每~75 s监测干质量和干质量密度，测量精度分别为1.3%和0.3%。我们发现悬浮生长的哺乳动物细胞在有丝分裂进入后会失去干质量并增加干质量密度。这些变化显示出很大的、非遗传的细胞间变异性，并且在中期-后期转变时发生逆转，之后干质量继续积累。干质量密度的变化导致有丝分裂早期浮力质量和干质量的差异，从而与已有的关于有丝分裂细胞生长的文献相吻合。机制上，细胞在有丝分裂早期增加溶酶体胞吐，抑制溶酶体胞吐减少有丝分裂中干质量损失和干质量密度增加。总之，我们的工作提供了一种监测单细胞干质量和干质量密度的新方法，并揭示了有丝分裂与广泛的胞吐介导的细胞内容物分泌相耦合。
Cell mass and composition change with cell cycle progression. Our previous work characterized buoyant mass dynamics in mitosis (Miettinen et al., 2019), but how dry mass and cell composition change in mitosis has remained unclear. To better understand mitotic cell growth and compositional changes, we develop a single-cell approach for monitoring dry mass and the density of that dry mass every ~75 s with 1.3% and 0.3% measurement precision, respectively. We find that suspension grown mammalian cells lose dry mass and increase dry mass density following mitotic entry. These changes display large, non-genetic cell-to-cell variability, and the changes are reversed at metaphase-anaphase transition, after which dry mass continues accumulating. The change in dry mass density causes buoyant and dry mass to differ specifically in early mitosis, thus reconciling existing literature on mitotic cell growth. Mechanistically, cells in early mitosis increase lysosomal exocytosis, and inhibition of lysosomal exocytosis decreases the dry mass loss and dry mass density increase in mitosis. Overall, our work provides a new approach for monitoring single-cell dry mass and dry mass density, and reveals that mitosis is coupled to extensive exocytosis-mediated secretion of cellular contents.