@article{WasmusDudek2020, author = {Wasmus, Christina and Dudek, Jan}, title = {Metabolic Alterations Caused by Defective Cardiolipin Remodeling in Inherited Cardiomyopathies}, series = {Life}, volume = {10}, journal = {Life}, number = {11}, issn = {2075-1729}, doi = {10.3390/life10110277}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219286}, year = {2020}, abstract = {The heart is the most energy-consuming organ in the human body. In heart failure, the homeostasis of energy supply and demand is endangered by an increase in cardiomyocyte workload, or by an insufficiency in energy-providing processes. Energy metabolism is directly associated with mitochondrial redox homeostasis. The production of toxic reactive oxygen species (ROS) may overwhelm mitochondrial and cellular ROS defense mechanisms in case of heart failure. Mitochondria are essential cell organelles and provide 95\% of the required energy in the heart. Metabolic remodeling, changes in mitochondrial structure or function, and alterations in mitochondrial calcium signaling diminish mitochondrial energy provision in many forms of cardiomyopathy. The mitochondrial respiratory chain creates a proton gradient across the inner mitochondrial membrane, which couples respiration with oxidative phosphorylation and the preservation of energy in the chemical bonds of ATP. Akin to other mitochondrial enzymes, the respiratory chain is integrated into the inner mitochondrial membrane. The tight association with the mitochondrial phospholipid cardiolipin (CL) ensures its structural integrity and coordinates enzymatic activity. This review focuses on how changes in mitochondrial CL may be associated with heart failure. Dysfunctional CL has been found in diabetic cardiomyopathy, ischemia reperfusion injury and the aging heart. Barth syndrome (BTHS) is caused by an inherited defect in the biosynthesis of cardiolipin. Moreover, a dysfunctional CL pool causes other types of rare inherited cardiomyopathies, such as Sengers syndrome and Dilated Cardiomyopathy with Ataxia (DCMA). Here we review the impact of cardiolipin deficiency on mitochondrial functions in cellular and animal models. We describe the molecular mechanisms concerning mitochondrial dysfunction as an incitement of cardiomyopathy and discuss potential therapeutic strategies.}, language = {en} } @phdthesis{Bertero2022, author = {Bertero, Edoardo}, title = {Mechano-energetic uncoupling in Barth syndrome cardiomyopathy}, doi = {10.25972/OPUS-25517}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-255176}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {In this Doctoral Thesis we investigated the consequences of perturbed mitochondrial calcium handling in the context of a rare human disease, Barth syndrome, in which the altered phospholipid composition of the inner mitochondrial membrane affects the structural organization of several protein complexes, including the mitochondrial calcium uniporter. We discovered that loss of the mitochondrial calcium uniporter in cardiac, but not skeletal muscle mitochondria hinders the calcium-induced adaptation of mitochondrial oxidative metabolism during workload transitions. This mechano-energetic uncoupling impairs the physiological increase in contractile force during physical exercise and might predispose Barth syndrome patients to the development of arrhythmias.}, language = {en} } @article{DudekMaack2022, author = {Dudek, Jan and Maack, Christoph}, title = {Mechano-energetic aspects of Barth syndrome}, series = {Journal of Inherited Metabolic Disease}, volume = {45}, journal = {Journal of Inherited Metabolic Disease}, number = {1}, doi = {10.1002/jimd.12427}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257512}, pages = {82-98}, year = {2022}, abstract = {Energy-demanding organs like the heart are strongly dependent on oxidative phosphorylation in mitochondria. Oxidative phosphorylation is governed by the respiratory chain located in the inner mitochondrial membrane. The inner mitochondrial membrane is the only cellular membrane with significant amounts of the phospholipid cardiolipin, and cardiolipin was found to directly interact with a number of essential protein complexes, including respiratory chain complexes I to V. An inherited defect in the biogenesis of cardiolipin causes Barth syndrome, which is associated with cardiomyopathy, skeletal myopathy, neutropenia and growth retardation. Energy conversion is dependent on reducing equivalents, which are replenished by oxidative metabolism in the Krebs cycle. Cardiolipin deficiency in Barth syndrome also affects Krebs cycle activity, metabolite transport and mitochondrial morphology. During excitation-contraction coupling, calcium (Ca\(^{2+}\)) released from the sarcoplasmic reticulum drives sarcomeric contraction. At the same time, Ca\(^{2+}\) influx into mitochondria drives the activation of Krebs cycle dehydrogenases and the regeneration of reducing equivalents. Reducing equivalents are essential not only for energy conversion, but also for maintaining a redox buffer, which is required to detoxify reactive oxygen species (ROS). Defects in CL may also affect Ca\(^{2+}\) uptake into mitochondria and thereby hamper energy supply and demand matching, but also detoxification of ROS. Here, we review the impact of cardiolipin deficiency on mitochondrial function in Barth syndrome and discuss potential therapeutic strategies.}, language = {en} } @article{RebsStreckfussBoemeke2023, author = {Rebs, Sabine and Streckfuss-B{\"o}meke, Katrin}, title = {How can we use stem cell-derived cardiomyocytes to understand the involvement of energetic metabolism in alterations of cardiac function?}, series = {Frontiers in Molecular Medicine}, volume = {3}, journal = {Frontiers in Molecular Medicine}, doi = {10.3389/fmmed.2023.1222986}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-327344}, year = {2023}, abstract = {Mutations in the mitochondrial-DNA or mitochondria related nuclear-encoded-DNA lead to various multisystemic disorders collectively termed mitochondrial diseases. One in three cases of mitochondrial disease affects the heart muscle, which is called mitochondrial cardiomyopathy (MCM) and is associated with hypertrophic, dilated, and noncompact cardiomyopathy. The heart is an organ with high energy demand, and mitochondria occupy 30\%-40\% of its cardiomyocyte-cell volume. Mitochondrial dysfunction leads to energy depletion and has detrimental effects on cardiac performance. However, disease development and progression in the context of mitochondrial and nuclear DNA mutations, remains incompletely understood. The system of induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CM) is an excellent platform to study MCM since the unique genetic identity to their donors enables a robust recapitulation of the predicted phenotypes in a dish on a patient-specific level. Here, we focus on recent insights into MCM studied by patient-specific iPSC-CM and further discuss research gaps and advances in metabolic maturation of iPSC-CM, which is crucial for the study of mitochondrial dysfunction and to develop novel therapeutic strategies.}, language = {en} }