Mutagenesis of mitochondrial DNA in Fuchs endothelial corneal dystrophy

• Mutagenesis of mtDNA in Fuchs corneal dystrophy (FECD) was investigated.
• mtDNAs from FECD patients had more lesions, copies and 4977-bp deletions.
• FECD patients slower repaired H2O2-induced mtDNA damage.
• FECD pathogenesis involves impairment in repair and degradation of mtDNA.

Fuchs endothelial corneal dystrophy (FECD) is an age-related, slowly progressive disease, which may lead to loss of vision resulting from apoptosis of corneal endothelial (CE) cells, dysfunction of Descemet membrane (DM) and corneal edema. A growing body of evidence suggests that oxidative stress may play a major role in the pathogenesis of FECD and that mitochondria of CE cells are its main target. Mitochondrial DNA (mtDNA) is particularly prone to oxidative stress and changes in mtDNA were reported in FECD patients. In the present work we studied mtDNA damage and repair, mtDNA copy number, and the 4977 bp common deletion in mtDNA in DM cells and peripheral blood lymphocytes (PBLs) isolated from FECD patients. PBLs from 35 FECD patients and 32 controls were challenged for 10 min with hydrogen peroxide at 20 μM and then left in a fresh medium for 3 h, resulting in a decrease in mtDNA copy number in both groups. Damage to mtDNA was not fully repaired after 3 h and the extent of remaining lesions was significantly higher in the patients than the controls. We observed a higher copy number and an increased extent of mtDNA damage as well as a higher ratio of the common 4977 bp deletion in DM cells of FECD patients than the controls. Our results confirm that mutagenesis of mtDNA may be involved in FECD pathogenesis and disturbance in mtDNA sensitivity to damaging agent as well as changes in mtDNA damage repair along with alternations in mtDNA copy number may underline this involvement.

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