Dynamic label-free imaging of lipid droplets and their link to fatty acid and pyruvate oxidation in mouse eggs

Bradley, Josephine, Pope, Iestyn ORCID: https://orcid.org/0000-0002-4104-0389, Wang, Yisu, Langbein, Wolfgang ORCID: https://orcid.org/0000-0001-9786-1023, Borri, Paola ORCID: https://orcid.org/0000-0002-7873-3314 and Swann, Karl ORCID: https://orcid.org/0000-0002-4355-1449 2019. Dynamic label-free imaging of lipid droplets and their link to fatty acid and pyruvate oxidation in mouse eggs. Journal of Cell Science 132 (13) , jcs228999. 10.1242/jcs.228999

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Abstract

Mammalian eggs generate most of their ATP by mitochondrial oxidation of pyruvate from the surrounding medium or from fatty acids that are stored as triacylglycerols within lipid droplets. The balance between pyruvate and fatty acid oxidation in generating ATP is not established. We have combined coherent anti-Stokes Raman scattering (CARS) imaging with deuterium labelling of oleic acid to monitor turnover of fatty acids within lipid droplets of living mouse eggs. We found that loss of labelled oleic acid is promoted by pyruvate removal but minimised when β-oxidation is inhibited. Pyruvate removal also causes a significant dispersion of lipid droplets, while inhibition of β-oxidation causes droplet clustering. Live imaging of luciferase or FAD autofluorescence from mitochondria, suggest that inhibition of β-oxidation in mouse eggs only leads to a transient decrease in ATP because there is compensatory uptake of pyruvate into mitochondria. Inhibition of pyruvate uptake followed by β-oxidation caused a similar and successive decline in ATP. Our data suggest that β-oxidation and pyruvate oxidation contribute almost equally to resting ATP production in resting mouse eggs and that reorganisation of lipid droplets occurs in response to metabolic demand.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy Biosciences
Publisher:	Company of Biologists
ISSN:	0021-9533
Date of First Compliant Deposit:	11 July 2019
Date of Acceptance:	28 May 2019
Last Modified:	19 Apr 2024 16:56
URI:	https://orca.cardiff.ac.uk/id/eprint/124154

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