Reappraisal of putative glyoxalase 1-deficient mouse and dicarbonyl stress on embryonic stem cells in vitro.
Glyoxalase 1 (Glo1) is a cytoplasmic enzyme with a cytoprotective function linked to metabolism of the cytotoxic side product of glycolysis, methylglyoxal (MG). It prevents dicarbonyl stress - the abnormal accumulation of reactive dicarbonyl metabolites, increasing protein and DNA damage. Increased Glo1 expression delays ageing and suppresses carcinogenesis, insulin resistance, cardiovascular disease and vascular complications of diabetes and renal failure. Surprisingly, gene trapping by the International Mouse Knockout Consortium (IMKC) to generate putative Glo1 knockout mice produced a mouse line with the phenotype characterised as normal and healthy. Here, we show that gene trapping mutation was successful, but the presence of Glo1 gene duplication, probably in the embryonic stem cells (ESCs) before gene trapping, maintained wild-type levels of Glo1 expression and activity and sustained the healthy phenotype. In further investigation of the consequences of dicarbonyl stress in ESCs, we found that prolonged exposure of mouse ESCs in culture to high concentrations of MG and/or hypoxia led to low-level increase in Glo1 copy number. In clinical translation, we found a high prevalence of low-level GLO1 copy number increase in renal failure where there is severe dicarbonyl stress. In conclusion, the IMKC Glo1 mutant mouse is not deficient in Glo1 expression through duplication of the Glo1 wild-type allele. Dicarbonyl stress and/or hypoxia induces low-level copy number alternation in ESCs. Similar processes may drive rare GLO1 duplication in health and disease.
['Shafie|Alaa|A|', 'Xue|Mingzhan|M|', 'Barker|Guy|G|', 'Zehnder|Daniel|D|', 'Thornalley|Paul J|PJ|', 'Rabbani|Naila|N|']
D000818:Animals D002478:Cells, Cultured D055028:Comparative Genomic Hybridization D004249:DNA Damage D053595:Embryonic Stem Cells D018628:Gene Dosage D005838:Genotype D006801:Humans D007791:Lactoylglutathione Lyase D051379:Mice D008810:Mice, Inbred C57BL D018345:Mice, Knockout D016133:Polymerase Chain Reaction D012150:Polymorphism, Restriction Fragment Length D011765:Pyruvaldehyde
glyoxalase dicarbonyl stress embryonic stem cell copy number variation methylglyoxal.