Different mitochondrial genetic defects exhibit the same protein signature of metabolism in skeletal muscle of PEO and MELAS patients: A role for oxidative stress

• Published in: Free radical biology & medicine Vol. 126; pp. 235 - 248
• Main Authors: Santacatterina, Fulvio, Torresano, Laura, Núñez-Salgado, Alfonso, Esparza-Molto, Pau B., Olive, Montse, Gallardo, Eduard, García-Arumi, Elena, Blazquez, Alberto, González-Quintana, Adrián, Martín, Miguel A., Cuezva, José M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-10-2018
• Subjects: Catalase; Metabolic enzymes; Mitochondrial diseases; Mn-superoxide dismutase; Oxidative stress; Protein arrays; Oxidative stress; NitTyr; RPPA; PYGM; Mitochondrial diseases; MDA; LDHA; 4-HNE; Catalase; CPT1; Mn-superoxide dismutase; PRx3; TK2; TRX; GSH; Metabolic enzymes; PDH-E1α; PRx6; ENO 1; G6PDH; TWNK; α-F1 and β-F1; KSS; GR; SOD2; SOD1; CS; HADHA; CORE II; Protein arrays; Hsp60; IF1; GPD1; LHON; ACO1; MELAS; PEO; GAPDH; MDs; SDH-B
• ISSN: 0891-5849; 1873-4596
• DOI: 10.1016/j.freeradbiomed.2018.08.020

A major challenge in mitochondrial diseases (MDs) is the identification of biomarkers that could inform of the mechanisms involved in the phenotypic expression of genetic defects. Herein, we have investigated the protein signature of metabolism and of the antioxidant response in muscle biopsies of clinically and genetically diagnosed patients with Progressive External Ophthalmoplegia due to single large-scale (PEO-sD) or multiple (PEO-mD) deletions of mtDNA and Mitochondrial Encephalopathy Lactic Acidosis and Stroke-like episode (MELAS) syndrome, and healthy donors. A high-throughput immunoassay technique that quantitates the expression of relevant proteins of glycolysis, glycogenolysis, pentose phosphate pathway, oxidative phosphorylation, pyruvate and fatty acid oxidation, tricarboxylic acid cycle and the antioxidant response in two large independent and retrospectively collected cohorts of PEO-sD, PEO-mD and MELAS patients revealed that despite the heterogeneity of the genetic alterations, the three MDs showed the same metabolic signatures in both cohorts of patients, which were highly divergent from those of healthy individuals. Linear Discriminant Analysis and Support Vector Machine classifier provided a minimum of four biomarkers to discriminate healthy from pathological samples. Regardless of the induction of a large number of enzymes involved in ameliorating oxidative stress, the down-regulation of mitochondrial superoxide dismutase (SOD2) and catalase expression favored the accumulation of oxidative damage in patients’ proteins. Down-regulation of SOD2 and catalase expression in MD patients is not due to relevant changes in the availability of their mRNAs, suggesting that oxidative stress regulates the expression of the two enzymes post-transcriptionally. We suggest that SOD2 and catalase could provide specific targets to improve the detoxification of reactive oxygen species that affects muscle proteins in these patients.
Summary of the alterations found in protein expression of metabolic and antioxidant enzymes in muscle biopsies of two independent cohorts of PEO and MELAS patients using reverse phase protein arrays. Genetic alterations are identified by red stars on nDNA and mtDNA. Red and green colors respectively denote decreased and enhanced expression of the indicated enzymes. Oxidative damage is depicted in a black background. [Display omitted]
•Quantification of metabolic proteins in muscle of MDs patients by RPPA.•Biopsies of PEO and MELAS patients portray the same proteome of metabolism.•Four protein biomarkers discriminate healthy from pathological samples.•Down-regulation of SOD2 and catalase are hallmarks of PEO and MELAS samples.•Oxidative damage occurs despite the induction of enzymes of the antioxidant response.