Mitochondrial morphology, bioenergetics and proteomic responses in fatty acid oxidation disorders
Serena Raimo,
Gabriella Zura-Miller,
Hossein Fezelinia,
Lynn A. Spruce,
Iordanis Zakopoulos,
Al-Walid Mohsen,
Jerry Vockley,
Harry Ischiropoulos
Affiliations
Serena Raimo
Children’s Hospital of Philadelphia Research Institute and Division of Neonatology, Departments of Pediatrics and Systems Pharmacology and Translational Therapeutics, the Raymond and Ruth Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
Gabriella Zura-Miller
Children’s Hospital of Philadelphia Research Institute and Division of Neonatology, Departments of Pediatrics and Systems Pharmacology and Translational Therapeutics, the Raymond and Ruth Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
Hossein Fezelinia
Proteomics Core Facility, Children's Hospital of Philadelphia, Philadelphia, PA, USA; Department of Biomedical Health and Informatics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
Lynn A. Spruce
Proteomics Core Facility, Children's Hospital of Philadelphia, Philadelphia, PA, USA
Iordanis Zakopoulos
Children’s Hospital of Philadelphia Research Institute and Division of Neonatology, Departments of Pediatrics and Systems Pharmacology and Translational Therapeutics, the Raymond and Ruth Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
Al-Walid Mohsen
Division of Medical Genetics, Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15224, USA; Department of Human Genetics, School of Public Health, Pittsburgh, PA 15261, USA
Jerry Vockley
Division of Medical Genetics, Department of Pediatrics, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15224, USA; Department of Human Genetics, School of Public Health, Pittsburgh, PA 15261, USA
Harry Ischiropoulos
Children’s Hospital of Philadelphia Research Institute and Division of Neonatology, Departments of Pediatrics and Systems Pharmacology and Translational Therapeutics, the Raymond and Ruth Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Corresponding author.
Mutations in nuclear genes encoding for mitochondrial proteins very long-chain acyl-CoA dehydrogenase (VLCAD) and trifunctional protein (TFP) cause rare autosomal recessive disorders. Studies in fibroblasts derived from patients with mutations in VLCAD and TFP exhibit mitochondrial defects. To gain insights on pathological changes that account for the mitochondrial deficits we performed quantitative proteomic, biochemical, and morphometric analyses in fibroblasts derived from subjects with three different VLCAD and three different TFP mutations. Proteomic data that was corroborated by antibody-based detection, indicated reduced levels of VLCAD and TFP protein in cells with VLCAD and TFP mutations respectively, which in part accounted for the diminished fatty acid oxidation capacity. Decreased mitochondrial respiratory capacity in cells with VLCAD and TFP mutations was quantified after glucose removal and cells with TFP mutations had lower levels of glycogen. Despite these energetic deficiencies, the cells with VLCAD and TFP mutations did not exhibit changes in mitochondria morphology, distribution, fusion and fission, quantified by either confocal or transmission electron microscopy and corroborated by proteomic and antibody-based protein analysis. Fibroblasts with VLCAD and to a lesser extend cells with TFP mutations had increased levels of mitochondrial respiratory chain proteins and proteins that facilitate the assembly of respiratory complexes. With the exception of reduced levels of catalase and glutathione S-transferase theta-1 in cells with TFP mutations, the levels of 45 proteins across all major intracellular antioxidant networks were similar between cells with VLCAD and TFP mutations and non-disease controls. Collectively the data indicate that despite the metabolic deficits, cells with VLCAD and TFP mutations maintain their proteomic integrity to preserve cellular and mitochondria architecture, support energy production and protect against oxidative stress.
