Journal of Bioenergetics and Biomembranes

, Volume 45, Issue 1, pp 101–109

Early alterations in mitochondrial reserve capacity; a means to predict subsequent photoreceptor cell death

Article

DOI: 10.1007/s10863-012-9477-5

Cite this article as:
Perron, N.R., Beeson, C. & Rohrer, B. J Bioenerg Biomembr (2013) 45: 101. doi:10.1007/s10863-012-9477-5

Abstract

Although genetic and environmental factors contribute to neurodegenerative disease, the underlying etiology common to many diseases might be based on metabolic demand. Mitochondria are the main producer of ATP, but are also the major source of reactive oxygen species. Under normal conditions, these oxidants are neutralized; however, under environmental insult or genetic susceptibility conditions, oxidative stress may exceed cellular antioxidant capacities, leading to degeneration. We tested the hypothesis that loss in mitochondrial reserve capacity plays a causative role in neuronal degeneration and chose a cone photoreceptor cell line as our model. 661W cells were exposed to agents that mimic oxidant stress or calcium overload. Real-time changes in cellular metabolism were assessed using the multi-well Seahorse Biosciences XF24 analyzer that measures oxygen consumption (OCR) and extracellular acidification rates (ECAR). Cellular stress resulted in an early loss of mitochondrial reserve capacity, without affecting basal respiration; and ECAR was increased, representing a compensatory shift of ATP productions toward glycolysis. The degree of change in energy metabolism was correlated with the amount of subsequent cell death 24-hours post-treatment, the concentration-dependent loss in mitochondrial reserve capacity correlated with the number of live cells. Our data suggested first, that loss in mitochondrial reserve capacity is a major contributor in disease pathogenesis; and second, that the XF24 assay might represent a useful surrogate assay amenable to the screening of agents that protect against loss of mitochondrial reserve capacity. In future experiments, we will explore these concepts for the development of neuroprotective agents.

Keywords

Mitochondrial respirationCell deathPhotoreceptorsRetinitis pigmentosa

Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  1. 1.Departments of OphthalmologyMedical University of South CarolinaCharlestonUSA
  2. 2.Departments of Pharmaceutical SciencesMedical University of South CarolinaCharlestonUSA
  3. 3.Departments of Research ServiceRalph H Johnson VA Medical CenterCharlestonUSA
  4. 4.College of Pharmacy/Pharmaceutical & Biomedical SciencesMedical University of South CarolinaCharlestonUSA