Preprint Article Version 1 This version is not peer-reviewed

An Isolated Complex V Inefficiency and Dysregulated Mitochondrial Function in Immortalized Lymphocytes from ME/CFS Patients

Version 1 : Received: 3 September 2019 / Approved: 4 September 2019 / Online: 4 September 2019 (13:29:14 CEST)
Version 2 : Received: 26 January 2020 / Approved: 27 January 2020 / Online: 27 January 2020 (10:09:08 CET)
Version 3 : Received: 2 February 2020 / Approved: 3 February 2020 / Online: 3 February 2020 (09:34:29 CET)

A peer-reviewed article of this Preprint also exists.

Missailidis, D.; Annesley, S.J.; Allan, C.Y.; Sanislav, O.; Lidbury, B.A.; Lewis, D.P.; Fisher, P.R. An Isolated Complex V Inefficiency and Dysregulated Mitochondrial Function in Immortalized Lymphocytes from ME/CFS Patients. Int. J. Mol. Sci. 2020, 21, 1074. Missailidis, D.; Annesley, S.J.; Allan, C.Y.; Sanislav, O.; Lidbury, B.A.; Lewis, D.P.; Fisher, P.R. An Isolated Complex V Inefficiency and Dysregulated Mitochondrial Function in Immortalized Lymphocytes from ME/CFS Patients. Int. J. Mol. Sci. 2020, 21, 1074.

Journal reference: Int. J. Mol. Sci. 2020, 21, ijms-672874
DOI: 10.3390/ijms21031074

Abstract

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is an enigmatic condition characterized by fatigue that is unaided by rest and by exacerbation of symptoms after exertion (post-exertional malaise or “PEM”). There is no definitive molecular marker or known underlying pathological mechanism for the condition. Increasing evidence for aberrant energy metabolism suggests a role for mitochondrial dysfunction in ME/CFS. Our objective was therefore to measure mitochondrial function and cellular stress sensing in actively metabolising patient blood cells. We immortalized lymphoblasts isolated from 51 ME/CFS patients diagnosed according to the Canadian Consensus Criteria and an age- and gender-matched control group. Parameters of mitochondrial function and energy stress sensing were assessed by Seahorse extracellular flux analysis, proteomics, and an array of additional biochemical assays. As a proportion of the basal oxygen consumption rate (OCR), the rate of ATP synthesis by Complex V was significantly reduced in ME/CFS lymphoblasts, while significant elevations were observed in Complex I OCR, maximum OCR, spare respiratory capacity, nonmitochondrial OCR and “proton leak” as a proportion of the basal OCR. This was accompanied by an elevation of mitochondrial membrane potential, chronically hyperactivated TOR Complex I stress signalling and upregulated expression of mitochondrial respiratory complexes, fatty acid transporters and enzymes of the β-oxidation and TCA cycles. By contrast, mitochondrial mass and genome copy number, as well as glycolytic rates and steady state ATP levels were unchanged. Our results suggest a model in which ME/CFS lymphoblasts have a Complex V defect accompanied by compensatory upregulation of their respiratory capacity that includes the mitochondrial respiratory complexes, membrane transporters and enzymes involved in fatty acid β-oxidation. This homeostatically returns ATP synthesis and steady state levels to “normal” in resting cells, but may leave them unable to adequately respond to acute increases in energy demand as the relevant homeostatic pathways are already activated.

Subject Areas

Myalgic Encephalomyelitis; Chronic Fatigue Syndrome; mitochondria; Complex V; TORC1; Seahorse respirometry.

Comments (1)

Comment 1
Received: 26 January 2020
Commenter: Paul Fisher
The commenter has declared there is no conflict of interests.
Comment: This 1st version of this manuscript contains an error which we would like to alert readers to:

During revision of the paper, we discovered an error in the spreadsheet formula calculating the mitochondrial membrane potential. This is calculated by dividing one quantity by another. However the original formular had been entered into the spreadsheet the wrong way round so that instead of "a" being divided by "b", "b" was divided by "a".

The result was that instead of the mitochondrial membrane potential being higher in ME/CFS lymphoblasts it was actually lower. The error has been corrected in a revised version of the article which has been submitted to Preprints.

The authors would like to apologize for this embarrassing calculation error.

Best regards to all readers
Paul Fisher on behalf of all authors.
+ Respond to this comment

We encourage comments and feedback from a broad range of readers. See criteria for comments and our diversity statement.

Leave a public comment
Send a private comment to the author(s)
Views 0
Downloads 0
Comments 1
Metrics 0


×
Alerts
Notify me about updates to this article or when a peer-reviewed version is published.