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Mustapha Irnaten, Diarmaid Hickey, Deirdre Brennan, William D Stamer, Abbot F Clark, Colm J O'Brien; Evidence of Increased Glycolysis and Glutaminolysis in Glaucoma Lamina Cribrosa Cells. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5650. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Increased synthesis and deposition of extracellular matrix (ECM) proteins in the lamina cribrosa (LC) is associated with LC dysfunction in glaucoma. We have previously shown mitochondrial dysfunction and an increased rate of proliferation in glaucomatous LC cells. Rapidly proliferating cells utilize alternative metabolic pathways to meet energy requirements. Monocarboxylate transporter (MCT1), glutaminase-2 (GLS2) and methylenetetrahydrofolate dehydrogenase/ cyclohydrolase-2 (MTHFD2) play a key role in cancer cell metabolism. The purpose of this study was to investigate the expression of markers (MCT1, GLS2 and MTFDH2) associated with an enhanced glycolysis and glutaminolysis phenotype.
GFAP negative LC cell lines obtained from normal and glaucoma human comparable age donors were cultured until passage 8. MCT1, GLS2 and MTFDH2 mRNA and TRP protein expression was measured using quantitative real-time RT-PCR and Western immunoblotting.
The results showed that transcription level of MCT1, GLS2 and MTFDH2 is significantly (p <0.05) enhanced in glaucoma LC cells (39.14 ± 3.17 fold change in gene transcription) vs normal LC cells (31.34 ± 2. 91), for MCT1 (35.69 ± 3.15) vs (17.63 ± 2.16) for GLS2, and (36.61 ± 4.12) vs (27.41 ± 1. 97) for MTFDH2.This was confirmed at protein expression level as Western immunoblotting analysis showed a significantly increased expression level of MCT1 and GLS2 in glaucoma LC cells, (9.41± 1.29 a.u) vs (6.04 ± 1.23), for MCT1 and (8.67 ± 1.23) vs (4.95 ± .0.98) for GLS2.
We found elevated expression levels of MCT1, GLS2 and MTFDH2, indicating enhanced glycolysis and glutaminolysis in glaucomatous LC cells. This is novel evidence that glaucomatous LC cells utilise alternative metabolic pathways. Blocking these pathological pathways would be a potential therapeutic in glaucoma.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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