CycleFlow simultaneously quantifies cell-cycle phase lengths and quiescence in vivo.
CycleFlow simultaneously quantifies cell-cycle phase lengths and quiescence in vivo.
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DOI:
10.1016/j.crmeth.2022.100315
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发表时间:
2022-10-24
期刊:
影响因子:
--
通讯作者:
Höfer T
中科院分区:
文献类型:
--
作者:
Jolly A;Fanti AK;Kongsaysak-Lengyel C;Claudino N;Gräßer I;Becker NB;Höfer T
Populations of stem, progenitor, or cancer cells show proliferative heterogeneity in vivo, comprising proliferating and quiescent cells. Consistent quantification of the quiescent subpopulation and progression of the proliferating cells through the individual phases of the cell cycle has not been achieved. Here, we describe CycleFlow, a method that robustly infers this comprehensive information from standard pulse-chase experiments with thymidine analogs. Inference is based on a mathematical model of the cell cycle, with realistic waiting time distributions for the G1, S, and G2/M phases and a long-term quiescent G0 state. We validate CycleFlow with an exponentially growing cancer cell line in vitro. Applying it to T cell progenitors in steady state in vivo, we uncover strong proliferative heterogeneity, with a minority of CD4+CD8+ T cell progenitors cycling very rapidly and then entering quiescence. CycleFlow is suitable as a routine method for quantitative cell-cycle analysis. CycleFlow quantifies quiescence and cell cycling in heterogeneous populations in vivo CycleFlow combines pulse chase with a thymidine analog with mathematical inference Accounting for experimental uncertainty yields robust estimates of cell-cycle parameters Application to T cell development quantifies thymocyte quiescence Assaying cell cycling with thymidine analogs in vivo is a standard method. However, the cell populations of interest are often heterogeneous, consisting of subpopulations of cycling and quiescent cells. Hence, the correct determination of the cell-cycle duration requires the simultaneous assessment of the quiescent fraction. Here, we show that a straightforward extension of the standard pulse-chase protocol, with a single thymidine analog, allows accurate determination of the quiescent cell fraction and of the cell-cycle phase durations in the proliferating subpopulation. Our method, CycleFlow, relies on measuring at several time points during the chase and interpreting the data with a realistic mathematical model of the cell cycle. CycleFlow yields robust estimates of the cell-cycle characteristics in the face of typical sources of experimental uncertainty. The switching of cells between cycling and quiescence is a fundamental process in development, tissue homeostasis, and immune responses. Jolly et al. describe a broadly applicable method that combines thymidine-analog labeling with model-based inference to disentangle and quantify quiescence and cycle timing.