La Trobe
1158833_Missailidis,D_2021.pdf (5.4 MB)

Dysregulated provision of oxidisable substrates to the mitochondria in me/cfs lymphoblasts

Download (5.4 MB)
journal contribution
posted on 15.04.2021, 06:13 by Daniel Missailidis, Oana Sanislav, Claire Allan, PK Smith, Sarah Annesley, Paul Fisher
Although understanding of the biomedical basis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is growing, the underlying pathological mechanisms remain uncertain. We recently reported a reduction in the proportion of basal oxygen consumption due to ATP synthesis by Complex V in ME/CFS patient-derived lymphoblast cell lines, suggesting mitochondrial respiratory inefficiency. This was accompanied by elevated respiratory capacity, elevated mammalian target of rapamycin complex 1 (mTORC1) signaling activity and elevated expression of enzymes involved in the TCA cycle, fatty acid β-oxidation and mitochondrial transport. These and other observations led us to hypothesise the dysregulation of pathways providing the mitochondria with oxidisable substrates. In our current study, we aimed to revisit this hypothesis by applying a combination of whole-cell transcriptomics, proteomics and energy stress signaling activity measures using subsets of up to 34 ME/CFS and 31 healthy control lymphoblast cell lines from our growing library. While levels of glycolytic enzymes were unchanged in accordance with our previous observations of unaltered glycolytic rates, the whole-cell proteomes of ME/CFS lymphoblasts contained elevated levels of enzymes involved in the TCA cycle (p = 1.03 × 10 ), the pentose phosphate pathway (p = 0.034, G6PD p = 5.5 × 10 ), mitochondrial fatty acid β-oxidation (p = 9.2 × 10 ), and degradation of amino acids including glutamine/glutamate (GLS p = 0.034, GLUD1 p = 0.048, GOT2 p = 0.026), branched-chain amino acids (BCKDHA p = 0.028, BCKDHB p = 0.031) and essential amino acids (FAH p = 0.036, GCDH p = 0.006). The activity of the major cellular energy stress sensor, AMPK, was elevated but the increase did not reach statistical significance. The results suggest that ME/CFS metabolism is dysregulated such that alternatives to glycolysis are more heavily utilised than in controls to provide the mitochondria with oxidisable substrates. −4 −4 −3

Funding

This research was funded by grants from The Judith Jane Mason& Harold StannettWilliams Memorial Foundation (The Mason Foundation) (grant IDs: MAS2016F063, MAS2018F00026) and The McCusker Charitable Foundation as well as donations from individual patients and supporters.

History

Publication Date

19/02/2021

Journal

International Journal of Molecular Sciences

Volume

22

Issue

4

Article Number

2046

Pagination

36p.

Publisher

MDPI

ISSN

1661-6596

Rights Statement

The Author reserves all moral rights over the deposited text and must be credited if any re-use occurs. Documents deposited in OPAL are the Open Access versions of outputs published elsewhere. Changes resulting from the publishing process may therefore not be reflected in this document. The final published version may be obtained via the publisher’s DOI. Please note that additional copyright and access restrictions may apply to the published version.