Oxidative lipidomics in Barth Syndrome

Mutations in the tafazzin gene cause Barth Syndrome, a rare disease presenting cardiomyopathy, skeletal muscle weakness, fatigue, neutropenia, and abnormal growth. Excess of reactive oxygen species (ROS) has been detected in tafazzin defective cardiomyocytes and it is considered among the main factors responsible for impaired sarcomere function in Barth syndrome. Although cardiolipin is considered the primary site of ROS attack in mitochondria, direct evidence of the presence of oxidized cardiolipin forms in Barth syndrome is missing in the literature. In order to investigate on the possible role of oxidized cardiolipin forms in Barth syndrome, it is important to identify precisely the chemical nature of oxidized cardiolipin forms and to study their effects on mitochondrial bioenergetic processes. In the present one-year research project, we plan to synthesize various oxidized cardiolipin forms by using available literature protocols and to characterize the oxidized phospholipids by MALDI-TOF/MS; preparative thin layer chromatography will be used to isolate and purify various oxidized cardiolipin species that will be used as reference standards in lipidomic studies of Barth mitochondria. The lipid profiles of heart mitochondria isolated from tafazzin-knock down (TAZ KD) mouse model of Barth syndrome will be analysed by MALDI-TOF/MS to search for oxidized cardiolipin forms. In addition, we will examine the effect of Elamipretide or Bendavia, a mitochondria-targeting peptide able to promote mitochondrial respiration and ATP production, on the level of cardiolipin and oxidized cardiolipin species. The basic findings resulting from the proposed investigation will help in unveiling the molecular role/effects of oxidized cardiolipin forms in Barth syndrome.