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PIMT and RBC metabolism
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Figure 2. Metabolomics and proteomics of PCMT1-/- knockout mouse red blood cells. (A) Metabolomics and proteomics of PCMT1-/- knockout (PCMT1 KO) mouse red blood cells (RBC); (B and C) Partial Least Square-Discriminant Analysis, Variable Importance in Projection; (D and E) top 50 metabolites and proteins by t-test between wild-type (WT), heterozygous PCMT1+/- (heterozygous PCMT1) and PCMT1 KO mice, respectively (only group averages are shown for proteomics data); (F) an overview of glycolysis, methionine metabolism, the pentose phosphate pathway and glutathione homeostasis in WT, heterozygous and PCMT1 KO mice; (G and H) tracing experi- ments with 1,2,3-13C3-glucose and 13C-methionine in WT and PCMT1 KO RBC prior to and after oxidant challenge with diamide. ROS: reactive oxygen species.
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and heat maps (top 25 significant metabolites by t-test) for each organ are provided in alphabetical order in Figure 3B to F. Of note, differences in brain phenotypes were comparable to those observed in RBC, including decreases in polyunsaturated fatty acids, hypotaurine and increases in PPP metabolites and SAM in the KO mice (Figure 3B). However, PCMT1 KO mouse brains were characterized by lower tryptophan and indole. In contrast, all the other organs showed metabolic pheno-
types clearly distinct from RBC and brains. In particular, hearts from KO mice were characterized by significant increases in the levels of several saturated fatty acids (7:0, 8:0, 10:0, 14:0, 16:0, 18:0) and decreased levels of purines (guanine, guanosine, hypoxanthine) and Krebs cycle metabolites (succinate – Figure 3C). Kidneys had similar trends with respect to purines (decreases in hypoxan- thine, xanthine and urate), but an opposite phenotype with respect to several fatty acids and related oxidation
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