Su, Xue Bessie;
Fedeli, Valeria;
Liu, Guizhen;
Amma, Meike Marie;
Boulasiki, Paraskevi;
Wang, Jingyi;
Bizzarri, Mariano;
... Saiardi, Adolfo; + view all
(2025)
Basic features of cellular inositol metabolism as revealed by a newly developed LC-MS method.
Biochemical Journal
, 482
(11)
pp. 675-690.
10.1042/BCJ20253028.
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Abstract
Inositol plays key roles in many cellular processes. Several studies focussed on the quantitative analysis of phosphorylated forms of inositol, enabled by analytical tools developed to detect these highly charged molecules. Direct measurement of free inositol however has been challenging because the molecule is uncharged and polar. As a result, the mechanisms maintaining the homeostasis of the inositol remains poorly understood. In this study, we overcome these challenges by developing a quantitative liquid chromatography– mass spectrometry (LC-MS) protocol that can resolve and quantify the three main sugar molecules present inside cells: glucose, fructose and inositol, as well as distinguish the clinically relevant isomers of inositol: myo-, scyllo- and chiro-inositol. The quantitative power of the new method was validated by accurately monitoring the changes of inositol levels under well-established conditions in Saccharomyces cerevisiae, where the endogenous synthesis of inositol is increased in the transcription repressor OPI1 knockout opi1Δ and decreased when wildtype yeast is fed with exogenous inositol. The method also revealed a new layer of regulation that takes place when exogenous inositol is added to further boost endogenous inositol synthesis in opi1Δ in a positive feedback loop. Analyses of mammalian cell lines provided many new insights into inositol metabolism. First, different cell lines displayed distinct sugar profiles and inositol concentrations and responded differently to inositol starvation. Second, mammalian cells can synthesise and import scyllo- but not chiro-inositol. Importantly, our method lent direct evidence to the previous hypothesis that lithium treatment could significantly reduce inositol levels in primary cortical neurons, thus diminishing the pool of free inositol available to the phosphoinositide cycle.
| Type: | Article |
|---|---|
| Title: | Basic features of cellular inositol metabolism as revealed by a newly developed LC-MS method |
| Location: | England |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1042/BCJ20253028 |
| Publisher version: | https://doi.org/10.1042/bcj20253028 |
| Language: | English |
| Additional information: | Copyright © 2025 The Author(s). This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY), https://creativecommons.org/licenses/by/4.0/. |
| Keywords: | Chiro-inositol, inositol depletion hypothesis, ISYNA1, Ino1, lithium, LC-MS, myo-inositol, Opi1, sugar, scyllo-inositol |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Lab for Molecular Cell Bio MRC-UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10213486 |
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