Monitoring and modeling of lymphocytic leukemia cell bioenergetics reveals decreased ATP synthesis during cell division

Joon Ho Kang,Matthew G Vander Heiden,Zhaoqi Li,Daniel Lim,Georgios Katsikis,Kiera M Sapp,Scott R Manalis,Max A Stockslager,Teemu P Miettinen,Michael B Yaffe

doi:10.1038/s41467-020-18769-y

Abstract

The energetic demands of a cell are believed to increase during mitosis, but the rates of ATP synthesis and consumption during mitosis have not been quantified. Here, we monitor mitochondrial membrane potential of single lymphocytic leukemia cells and demonstrate that mitochondria hyperpolarize from the G2/M transition until the metaphase-anaphase transition. This hyperpolarization was dependent on cyclin-dependent kinase 1 (CDK1) activity. By using an electrical circuit model of mitochondria, we quantify mitochondrial ATP synthesis rates in mitosis from the single-cell time-dynamics of mitochondrial membrane potential. We find that mitochondrial ATP synthesis decreases by approximately 50% during early mitosis and increases back to G2 levels during cytokinesis. Consistently, ATP levels and ATP synthesis are lower in mitosis than in G2 in synchronized cell populations. Overall, our results provide insights into mitotic bioenergetics and suggest that cell division is not a highly energy demanding process.

Highlights

The energetic demands of a cell are believed to increase during mitosis, but the rates of adenosine triphosphate (ATP) synthesis and consumption during mitosis have not been quantified
We examined the murine lymphocytic leukemia cell line L1210 grown in the presence of non-quenching concentrations (10 nM) of tetramethylrhodamine ethyl ester (TMRE), a fluorescent probe for ΔΨm25 (Supplementary Fig. 2a and Supplementary Note 2)
Because we found that cyclin-dependent kinase 1 (CDK1) activity is responsible for the mitochondrial hyperpolarization (Fig. 2), and because CDK1 has been shown to activate in a switch-like manner[36,37,38], we set the circuit to behave in a switch-like manner between active CDK1 (CDK1on, from the G2/M transition to the metaphase–anaphase transition) and inactive CDK1 (CDK1off, G2 and cytokinesis) states, while accounting for the short duration when CDK1 activity is converting from one state to another (Supplementary Note 5)

Summary

Introduction

The energetic demands of a cell are believed to increase during mitosis, but the rates of ATP synthesis and consumption during mitosis have not been quantified. Studies in synchronized cells have shown that mitochondrial ETC activity increases in mitosis[4,15,18], at least partly due to CDK1 directly activating ETC complex I4 Whether this increase in ETC activity is coupled to increased ATP synthesis remains unclear[4,19,20]. The levels of reactive oxygen species (ROS) increase during prolonged mitosis[21] Overall, these results suggest that the bioenergetic state of cells arrested in mitosis differs radically from interphase cells. Encoded ATP sensors have revealed that cellular ATP levels gradually decrease from the G2/M transition until the metaphase–anaphase transition, after which ATP levels rapidly recover during the anaphase[3,7,17] These results have been attributed to the presumably high ATP consumption during early mitosis, ATP synthesis and consumption in mitosis have not been quantified. ROS levels are known to increase during normal mitosis, supporting the notion that the bioenergetic state of cells changes during unperturbed mitosis

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