Potential conflict of interest: Nothing to report.
Mitochondrial function and morphology are impaired in parkin-mutant fibroblasts†
Article first published online: 9 DEC 2008
Copyright © 2008 American Neurological Association
Annals of Neurology
Volume 64, Issue 5, pages 555–565, November 2008
How to Cite
Mortiboys, H., Thomas, K. J., Koopman, W. J. H., Klaffke, S., Abou-Sleiman, P., Olpin, S., Wood, N. W., Willems, P. H. G. M., Smeitink, J. A. M., Cookson, M. R. and Bandmann, O. (2008), Mitochondrial function and morphology are impaired in parkin-mutant fibroblasts. Ann Neurol., 64: 555–565. doi: 10.1002/ana.21492
- Issue published online: 9 DEC 2008
- Article first published online: 9 DEC 2008
- Manuscript Accepted: 8 JUL 2008
- Manuscript Revised: 4 JUL 2008
- Manuscript Received: 9 APR 2008
- Parkinson's Disease Society (UK). Grant Number: G-0715
- Sheila McKenzie Fund of the University of Sheffield
- Intramural Research Program of the NIH (National Institute on Aging). Grant Number: Z01 AG000953-07
- Innovative Research Projects (IOP)-genomics project entitled “New tools for the identification of nutritional modulators of mitochondrial activity: small molecules that promote health and combat disease”. Grant Number: IGE05003
There are marked mitochondrial abnormalities in parkin-knock-out Drosophila and other model systems. The aim of our study was to determine mitochondrial function and morphology in parkin-mutant patients. We also investigated whether pharmacological rescue of impaired mitochondrial function may be possible in parkin-mutant human tissue.
We used three sets of techniques, namely, biochemical measurements of mitochondrial function, quantitative morphology, and live cell imaging of functional connectivity to assess the mitochondrial respiratory chain, the outer shape and connectivity of the mitochondria, and their functional inner connectivity in fibroblasts from patients with homozygous or compound heterozygous parkin mutations.
Parkin-mutant cells had lower mitochondrial complex I activity and complex I–linked adenosine triphosphate production, which correlated with a greater degree of mitochondrial branching, suggesting that the functional and morphological effects of parkin are related. Knockdown of parkin in control fibroblasts confirmed that parkin deficiency is sufficient to explain these mitochondrial effects. In contrast, 50% knockdown of parkin, mimicking haploinsufficiency in human patient tissue, did not result in impaired mitochondrial function or morphology. Fluorescence recovery after photobleaching assays demonstrated a lower level of functional connectivity of the mitochondrial matrix, which further worsened after rotenone exposure. Treatment with experimental neuroprotective compounds resulted in a rescue of the mitochondrial membrane potential.
Our study demonstrates marked abnormalities of mitochondrial function and morphology in parkin-mutant patients and provides proof-of-principle data for the potential usefulness of this new model system as a tool to screen for disease-modifying compounds in genetically homogenous parkinsonian disorders. Ann Neurol 2008;64:555–565