Post-translational modifications (PTMs) regulate enzyme structure and function to expand the functional proteome; many of these PTMs are a direct result of cellular metabolism, serving as regulatory mechanisms. Specifically, modifications by the glycolytic by-product methylglyoxal (MGO) have been implicated in diabetic nephropathy and non-alcoholic fatty liver disease (NAFLD). Furthermore, decreased expression of glyoxalase I (GLO1), the major enzyme to detoxify MGO, has also been associated with metabolic disorders. Herein, we demonstrate the generation and characterization of Glo1 knockout mice (KO). When fed a high-fat, high sucrose (HFHS) diet, wild-type mice show significant hepatic lipid accumulation, liver injury, and serum alanine aminotransferase activity. These effects are blunted in KO mice. Furthermore, wild-type mice show significant glucose intolerance following this feeding regimen, an effect that is blocked in KO mice. Using QuARKMod to quantify the global Arg and Lys PTM landscape, we show that MGO-derived PTMs are significantly elevated in HFHS fed KO mice, while HFHS fed WT mice do not exhibit these changes. Our data support the growing notion that low levels of MGO may play a role in hormesis, finely tuning metabolism to restore homeostasis.

<b>Figure 1. Glucose tolerance is restored in KO mice </b>(a) The glyoxalase cycle. (b) Western blotting of WT and KO mice. (c) Body weight was measured once per week. (d) Change in body weight over the 16-week study in each cohort.

Figure 1. Glucose tolerance is restored in KO mice (a) The glyoxalase cycle. (b) Western blotting of WT and KO mice. (c) Body weight was measured once per week. (d) Change in body weight over the 16-week study in each cohort.

<b>Figure 2. MGO modifications and Lys acetylation are elevated in HFHS-fed KO mice. </b>(a) MGO-generated Lys and Arg PTMs. (b) Hepatic MGO levels. (c-e) MGO-derived liver PTMs are significantly elevated in HFHS-fed KO mice compared to HFHS-fed WT mice. (f) acLys is significantly elevated in HFHS-fed KO mice.

Figure 2. MGO modifications and Lys acetylation are elevated in HFHS-fed KO mice. (a) MGO-generated Lys and Arg PTMs. (b) Hepatic MGO levels. (c-e) MGO-derived liver PTMs are significantly elevated in HFHS-fed KO mice compared to HFHS-fed WT mice. (f) acLys is significantly elevated in HFHS-fed KO mice.

James Galligan

The University of Arizona College of Pharmacy

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