Abstract
Purpose :
Lamina Cribrosa is the main site of damage in glaucomatous optic neuropathy. We have previously shown that Glaucoma lamina cribrosa (GLC) cells have an increased profibrotic gene expression and altered mitochondrial function in the form of reduced mitochondrial membrane potential when compared to normal lamina cribrosa (NLC) cells. Here we demonstrate a more detailed systematic bioenergetic assessment of these activated myofibroblasts contributing to optic disc cupping in glaucoma
Methods :
GLC cells from three donors and NLC cells from three age-matched controls were assessed using VICTOR X4 PerkinElmer plate reader with different luminescent probes. Three measurements were assessed: ATP production, Oxygen Consumption Rate (OCR) and Extracellular Acidification (ECA). All were performed in triplicates and were normalized to total protein biomass
Results :
GLC cells produced significantly less (p<0.05) ATP than NLC cells at baseline (73.51±7.41 a.u. vs 85.52±9.1 a.u. respectively). The difference reaches >20% when mitochondria are stressed using galactose instead of glucose to prevent glycolysis. (72.11±7.17 a.u. vs 92.26±13.41 a.u. respectively p<0.05). GLC cells showed diminished basal oxygen consumption compared to NLC cells (1.99±0.80 vs 7.73±1.9 nmole/min*mg protein respectively p<0.05) with less mitochondrial reserve capacity when uncoupled with Carbonyl cyanide-4-phynylhydrazone (FCCP) (4.94±0.6 vs 13.28±1.28 nmole/min*mg protein respectively p<0.05). Finally, GLC cells showed more lactate contribution in ECA compared to NLC cells (85.97±3.71% vs 63.97±9.34% respectively p<0.05), suggesting increased anaerobic glycolysis and decreased oxidative phosphorylation (OXPHOS) in GLC cells
Conclusions :
GLC cells show evidence of mitochondrial dysfunction including lower OXPHOS and higher anaerobic glycolysis compared to NLC cells (Warburg effect). Better understanding of mitochondrial function in glaucoma may help to develop new therapeutics
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.