Lookup NU author(s): Dr Laura Greaves,
Professor Robert Taylor
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2018 The Authors. Defects in the respiratory chain, interfering with energy production in the cell, are major underlying causes of mitochondrial diseases. In spite of this, the surprising variety of clinical symptoms, disparity between ages of onset, as well as the involvement of mitochondrial impairment in ageing and age-related diseases continue to challenge our understanding of the pathogenic processes. This complexity can be in part attributed to the unique metabolic needs of organs or of various cell types. In this view, it remains essential to investigate mitochondrial dysfunction at the cellular level. For this purpose, we developed a novel enzyme histochemical method that enables precise quantification in fresh-frozen tissues using competing redox reactions which ultimately lead to the reduction of tetrazolium salts and formazan deposition in cytochrome c oxidase-deficient mitochondria. We demonstrate that the loss of oxidative activity is detected at very low levels - this achievement is unequalled by previous techniques and opens up new opportunities for the study of early disease processes or comparative investigations. Moreover, human biopsy samples of mitochondrial disease patients of diverse genotypic origins were used and the successful detection of COX-deficient cells suggests a broad application for this new method. Lastly, the assay can be adapted to a wide range of tissues in the mouse and extends to other animal models, which we show here with the fruit fly, Drosophila melanogaster. Overall, the new assay provides the means to quantify and map, on a cell-by-cell basis, the full extent of COX deficiency in tissues, thereby expending new possibilities for future investigation.
Author(s): Simard M-L, Mourier A, Greaves LC, Taylor RW, Stewart JB
Publication type: Article
Publication status: Published
Journal: Journal of Pathology
Print publication date: 01/07/2018
Online publication date: 16/04/2018
Acceptance date: 16/04/2018
Date deposited: 04/06/2018
ISSN (print): 0022-3417
ISSN (electronic): 1096-9896
Publisher: John Wiley and Sons Ltd
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