The accumulation of un-repairable DNA damage in laminopathy progeria fibroblasts is caused by ROS generation and is prevented by treatment with N-acetyl cysteine

Richards, S.A.; Muter, J.; Ritchie, P.; Lattanzi, G.; Hutchison, C.J.

Abstract

Fibroblasts from patients with the severe laminopathy diseases, Restrictive Dermopathy (RD) & Hutchinson Gilford Progeria Syndrome (HGPS), are characterised by poor growth in culture, the presence of abnormally shaped nuclei and the accumulation of DNA double strand breaks (DSB). Here we show that the accumulation of DSB and poor growth of the fibroblasts but not the presence of abnormally shaped nuclei are caused by elevated levels of ROS and greater sensitivity to oxidative stress. Basal levels of ROS and sensitivity to H2O2 were compared in fibroblasts from normal, RD and HGPS individuals using FACS based assays. Basal levels of ROS and stimulated levels of ROS were both five-fold higher in the progeria fibroblasts. Elevated levels of ROS were correlated with lower proliferation indices but not with the presence of abnormally shaped nuclei. DSB induced by etoposide were repaired efficiently in normal, RD and HGPS fibroblasts. In contrast, DSB induced by ROS were repaired efficiently in normal fibroblasts but in RD and HGPS fibroblasts many ROS induced DSB were un-repairable. The accumulation of ROS induced DSB appeared to cause the poor growth of RD and HGPS fibroblasts, since culture in the presence of the ROS scavenger N-acetyl cysteine (NAC) reduced the basal levels of DSB, eliminated un-repairable ROS induced DSB, and greatly improved population-doubling times. Our findings suggest that un-repaired ROS induced DSB contribute significantly to the RD & HGPS phenotypes and that inclusion of NAC in a combinatorial therapy might prove beneficial to HGPS patients.

Citation

Richards, S., Muter, J., Ritchie, P., Lattanzi, G., & Hutchison, C. (2011). The accumulation of un-repairable DNA damage in laminopathy progeria fibroblasts is caused by ROS generation and is prevented by treatment with N-acetyl cysteine. Human Molecular Genetics, 20(20), 3997-4004. https://doi.org/10.1093/hmg/ddr327

• Journal Article Type: Article
• Publication Date: 2011
• Deposit Date: Jul 21, 2011
• Journal: Human Molecular Genetics
• Print ISSN: 0964-6906
• Electronic ISSN: 1460-2083
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 20
• Issue: 20
• Pages: 3997-4004
• DOI: https://doi.org/10.1093/hmg/ddr327
• Public URL: https://durham-repository.worktribe.com/output/1507101
• Publisher URL: http://hmg.oxfordjournals.org/content/20/20/3997