@article{JanzWalzCirnuetal.2024,
  author    = {Janz, Anna and Walz, Katharina and Cirnu, Alexandra and Surjanto, Jessica and Urlaub, Daniela and Leskien, Miriam and Kohlhaas, Michael and Nickel, Alexander and Brand, Theresa and Nose, Naoko and W{\"o}rsd{\"o}rfer, Philipp and Wagner, Nicole and Higuchi, Takahiro and Maack, Christoph and Dudek, Jan and Lorenz, Kristina and Klopocki, Eva and Erg{\"u}n, S{\"u}leyman and Duff, Henry J. and Gerull, Brenda},
  title     = {Mutations in DNAJC19 cause altered mitochondrial structure and increased mitochondrial respiration in human iPSC-derived cardiomyocytes},
  series = {Molecular Metabolism},
  volume    = {79},
  journal   = {Molecular Metabolism},
  issn      = {2212-8778},
  doi       = {10.1016/j.molmet.2023.101859},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350393},
  year      = {2024},
  abstract  = {Highlights • Loss of DNAJC19's DnaJ domain disrupts cardiac mitochondrial structure, leading to abnormal cristae formation in iPSC-CMs. • Impaired mitochondrial structures lead to an increased mitochondrial respiration, ROS and an elevated membrane potential. • Mutant iPSC-CMs show sarcomere dysfunction and a trend to more arrhythmias, resembling DCMA-associated cardiomyopathy. Background Dilated cardiomyopathy with ataxia (DCMA) is an autosomal recessive disorder arising from truncating mutations in DNAJC19, which encodes an inner mitochondrial membrane protein. Clinical features include an early onset, often life-threatening, cardiomyopathy associated with other metabolic features. Here, we aim to understand the metabolic and pathophysiological mechanisms of mutant DNAJC19 for the development of cardiomyopathy. Methods We generated induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) of two affected siblings with DCMA and a gene-edited truncation variant (tv) of DNAJC19 which all lack the conserved DnaJ interaction domain. The mutant iPSC-CMs and their respective control cells were subjected to various analyses, including assessments of morphology, metabolic function, and physiological consequences such as Ca\(^{2+}\) kinetics, contractility, and arrhythmic potential. Validation of respiration analysis was done in a gene-edited HeLa cell line (DNAJC19tv\(_{HeLa}\)). Results Structural analyses revealed mitochondrial fragmentation and abnormal cristae formation associated with an overall reduced mitochondrial protein expression in mutant iPSC-CMs. Morphological alterations were associated with higher oxygen consumption rates (OCRs) in all three mutant iPSC-CMs, indicating higher electron transport chain activity to meet cellular ATP demands. Additionally, increased extracellular acidification rates suggested an increase in overall metabolic flux, while radioactive tracer uptake studies revealed decreased fatty acid uptake and utilization of glucose. Mutant iPSC-CMs also showed increased reactive oxygen species (ROS) and an elevated mitochondrial membrane potential. Increased mitochondrial respiration with pyruvate and malate as substrates was observed in mutant DNAJC19tv HeLa cells in addition to an upregulation of respiratory chain complexes, while cellular ATP-levels remain the same. Moreover, mitochondrial alterations were associated with increased beating frequencies, elevated diastolic Ca\(^{2+}\) concentrations, reduced sarcomere shortening and an increased beat-to-beat rate variability in mutant cell lines in response to β-adrenergic stimulation. Conclusions Loss of the DnaJ domain disturbs cardiac mitochondrial structure with abnormal cristae formation and leads to mitochondrial dysfunction, suggesting that DNAJC19 plays an essential role in mitochondrial morphogenesis and biogenesis. Moreover, increased mitochondrial respiration, altered substrate utilization, increased ROS production and abnormal Ca\(^{2+}\) kinetics provide insights into the pathogenesis of DCMA-related cardiomyopathy.},
  language  = {en}
}
@article{SchwemmleinMaackBertero2022,
  author    = {Schwemmlein, Julia and Maack, Christoph and Bertero, Edoardo},
  title     = {Mitochondria as therapeutic targets in heart failure},
  series = {Current Heart Failure Reports},
  volume    = {19},
  journal   = {Current Heart Failure Reports},
  number    = {2},
  doi       = {10.1007/s11897-022-00539-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324015},
  pages     = {27-37},
  year      = {2022},
  abstract  = {Purpose of Review We review therapeutic approaches aimed at restoring function of the failing heart by targeting mitochondrial reactive oxygen species (ROS), ion handling, and substrate utilization for adenosine triphosphate (ATP) production. Recent Findings Mitochondria-targeted therapies have been tested in animal models of and humans with heart failure (HF). Cardiac benefits of sodium/glucose cotransporter 2 inhibitors might be partly explained by their effects on ion handling and metabolism of cardiac myocytes. Summary The large energy requirements of the heart are met by oxidative phosphorylation in mitochondria, which is tightly regulated by the turnover of ATP that fuels cardiac contraction and relaxation. In heart failure (HF), this mechano-energetic coupling is disrupted, leading to bioenergetic mismatch and production of ROS that drive the progression of cardiac dysfunction. Furthermore, HF is accompanied by changes in substrate uptake and oxidation that are considered detrimental for mitochondrial oxidative metabolism and negatively affect cardiac efficiency. Mitochondria lie at the crossroads of metabolic and energetic dysfunction in HF and represent ideal therapeutic targets.},
  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{LjubojevićHolzerKralerDjalinacetal.2022,
  author    = {Ljubojević-Holzer, Senka and Kraler, Simon and Djalinac, Nataša and Abdellatif, Mahmoud and Voglhuber, Julia and Schipke, Julia and Schmidt, Marlene and Kling, Katharina-Maria and Franke, Greta Therese and Herbst, Viktoria and Zirlik, Andreas and von Lewinski, Dirk and Scherr, Daniel and Rainer, Peter P and Kohlhaas, Michael and Nickel, Alexander and M{\"u}hlfeld, Christian and Maack, Christoph and Sedej, Simon},
  title     = {Loss of autophagy protein ATG5 impairs cardiac capacity in mice and humans through diminishing mitochondrial abundance and disrupting Ca2+ cycling},
  series = {Cardiovascular Research},
  volume    = {118},
  journal   = {Cardiovascular Research},
  doi       = {10.1093/cvr/cvab112},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-369345},
  pages     = {1492-1505},
  year      = {2022},
  abstract  = {Aims Autophagy protects against the development of cardiac hypertrophy and failure. While aberrant Ca2+ handling promotes myocardial remodelling and contributes to contractile dysfunction, the role of autophagy in maintaining Ca2+ homeostasis remains elusive. Here, we examined whether Atg5 deficiency-mediated autophagy promotes early changes in subcellular Ca2+ handling in ventricular cardiomyocytes, and whether those alterations associate with compromised cardiac reserve capacity, which commonly precedes the onset of heart failure. Methods and results RT-qPCR and immunoblotting demonstrated reduced Atg5 gene and protein expression and decreased abundancy of autophagy markers in hypertrophied and failing human hearts. The function of ATG5 was examined using cardiomyocyte-specific Atg5-knockout mice (Atg5-/-). Before manifesting cardiac dysfunction, Atg5-/- mice showed compromised cardiac reserve in response to β-adrenergic stimulation. Consequently, effort intolerance and maximal oxygen consumption were reduced during treadmill-based exercise tolerance testing. Mechanistically, cellular imaging revealed that Atg5 deprivation did not alter spatial and functional organization of intracellular Ca2+ stores or affect Ca2+ cycling in response to slow pacing or upon acute isoprenaline administration. However, high-frequency stimulation exposed stunted amplitude of Ca2+ transients, augmented nucleoplasmic Ca2+ load, and increased CaMKII activity, especially in the nuclear region of hypertrophied Atg5-/- cardiomyocytes. These changes in Ca2+ cycling were recapitulated in hypertrophied human cardiomyocytes. Finally, ultrastructural analysis revealed accumulation of mitochondria with reduced volume and size distribution, meanwhile functional measurements showed impaired redox balance in Atg5-/- cardiomyocytes, implying energetic unsustainability due to overcompensation of single mitochondria, particularly under increased workload. Conclusion Loss of cardiac Atg5-dependent autophagy reduces mitochondrial abundance and causes subtle alterations in subcellular Ca2+ cycling upon increased workload in mice. Autophagy-related impairment of Ca2+ handling is progressively worsened by β-adrenergic signalling in ventricular cardiomyocytes, thereby leading to energetic exhaustion and compromised cardiac reserve.},
  language  = {en}
}
@article{MorgensternPeikertLuebbertetal.2021,
  author    = {Morgenstern, Marcel and Peikert, Christian D. and L{\"u}bbert, Philipp and Suppanz, Ida and Klemm, Cinzia and Alka, Oliver and Steiert, Conny and Naumenko, Nataliia and Schendzielorz, Alexander and Melchionda, Laura and M{\"u}hlh{\"a}user, Wignand W. D. and Knapp, Bettina and Busch, Jakob D. and Stiller, Sebastian B. and Dannenmaier, Stefan and Lindau, Caroline and Licheva, Mariya and Eickhorst, Christopher and Galbusera, Riccardo and Zerbes, Ralf M. and Ryan, Michael T. and Kraft, Claudine and Kozjak-Pavlovic, Vera and Drepper, Friedel and Dennerlein, Sven and Oeljeklaus, Silke and Pfanner, Nikolaus and Wiedemann, Nils and Warscheid, Bettina},
  title     = {Quantitative high-confidence human mitochondrial proteome and its dynamics in cellular context},
  series = {Cell Metabolism},
  volume    = {33},
  journal   = {Cell Metabolism},
  doi       = {10.1016/j.cmet.2021.11.001},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-371114},
  pages     = {2464-2483},
  year      = {2021},
  abstract  = {Mitochondria are key organelles for cellular energetics, metabolism, signaling, and quality control and have been linked to various diseases. Different views exist on the composition of the human mitochondrial proteome. We classified >8,000 proteins in mitochondrial preparations of human cells and defined a mitochondrial high-confidence proteome of >1,100 proteins (MitoCoP). We identified interactors of translocases, respiratory chain, and ATP synthase assembly factors. The abundance of MitoCoP proteins covers six orders of magnitude and amounts to 7\% of the cellular proteome with the chaperones HSP60-HSP10 being the most abundant mitochondrial proteins. MitoCoP dynamics spans three orders of magnitudes, with half-lives from hours to months, and suggests a rapid regulation of biosynthesis and assembly processes. 460 MitoCoP genes are linked to human diseases with a strong prevalence for the central nervous system and metabolism. MitoCoP will provide a high-confidence resource for placing dynamics, functions, and dysfunctions of mitochondria into the cellular context.},
  language  = {en}
}
@article{WagnerBerteroNickeletal.2020,
  author    = {Wagner, Michael and Bertero, Edoardo and Nickel, Alexander and Kohlhaas, Michael and Gibson, Gary E. and Heggermont, Ward and Heymans, Stephane and Maack, Christoph},
  title     = {Selective NADH communication from α-ketoglutarate dehydrogenase to mitochondrial transhydrogenase prevents reactive oxygen species formation under reducing conditions in the heart},
  series = {Basic Research in Cardiology},
  volume    = {115},
  journal   = {Basic Research in Cardiology},
  issn      = {0300-8428},
  doi       = {10.1007/s00395-020-0815-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-234907},
  year      = {2020},
  abstract  = {In heart failure, a functional block of complex I of the respiratory chain provokes superoxide generation, which is transformed to H\(_2\)O\(_2\) by dismutation. The Krebs cycle produces NADH, which delivers electrons to complex I, and NADPH for H\(_2\)O\(_2\) elimination via isocitrate dehydrogenase and nicotinamide nucleotide transhydrogenase (NNT). At high NADH levels, α-ketoglutarate dehydrogenase (α-KGDH) is a major source of superoxide in skeletal muscle mitochondria with low NNT activity. Here, we analyzed how α-KGDH and NNT control H\(_2\)O\(_2\) emission in cardiac mitochondria. In cardiac mitochondria from NNT-competent BL/6N mice, H\(_2\)O\(_2\) emission is equally low with pyruvate/malate (P/M) or α-ketoglutarate (α-KG) as substrates. Complex I inhibition with rotenone increases H2O2 emission from P/M, but not α-KG respiring mitochondria, which is potentiated by depleting H\(_2\)O\(_2\)-eliminating capacity. Conversely, in NNT-deficient BL/6J mitochondria, H2O2 emission is higher with α-KG than with P/M as substrate, and further potentiated by complex I blockade. Prior depletion of H\(_2\)O\(_2\)-eliminating capacity increases H\(_2\)O\(_2\) emission from P/M, but not α-KG respiring mitochondria. In cardiac myocytes, downregulation of α-KGDH activity impaired dynamic mitochondrial redox adaptation during workload transitions, without increasing H\(_2\)O\(_2\) emission. In conclusion, NADH from α-KGDH selectively shuttles to NNT for NADPH formation rather than to complex I of the respiratory chain for ATP production. Therefore, α-KGDH plays a key role for H\(_2\)O\(_2\) elimination, but is not a relevant source of superoxide in heart. In heart failure, α-KGDH/NNT-dependent NADPH formation ameliorates oxidative stress imposed by complex I blockade. Downregulation of α-KGDH may, therefore, predispose to oxidative stress in heart failure.},
  language  = {en}
}
@article{KunzGoetzGaoetal.2020,
  author    = {Kunz, Tobias C. and G{\"o}tz, Ralph and Gao, Shiqiang and Sauer, Markus and Kozjak-Pavlovic, Vera},
  title     = {Using Expansion Microscopy to Visualize and Characterize the Morphology of Mitochondrial Cristae},
  series = {Frontiers in Cell and Developmental Biology},
  volume    = {8},
  journal   = {Frontiers in Cell and Developmental Biology},
  issn      = {2296-634X},
  doi       = {10.3389/fcell.2020.00617},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-208296},
  year      = {2020},
  abstract  = {Mitochondria are double membrane bound organelles indispensable for biological processes such as apoptosis, cell signaling, and the production of many important metabolites, which includes ATP that is generated during the process known as oxidative phosphorylation (OXPHOS). The inner membrane contains folds called cristae, which increase the membrane surface and thus the amount of membrane-bound proteins necessary for the OXPHOS. These folds have been of great interest not only because of their importance for energy conversion, but also because changes in morphology have been linked to a broad range of diseases from cancer, diabetes, neurodegenerative diseases, to aging and infection. With a distance between opposing cristae membranes often below 100 nm, conventional fluorescence imaging cannot provide a resolution sufficient for resolving these structures. For this reason, various highly specialized super-resolution methods including dSTORM, PALM, STED, and SIM have been applied for cristae visualization. Expansion Microscopy (ExM) offers the possibility to perform super-resolution microscopy on conventional confocal microscopes by embedding the sample into a swellable hydrogel that is isotropically expanded by a factor of 4-4.5, improving the resolution to 60-70 nm on conventional confocal microscopes, which can be further increased to ∼ 30 nm laterally using SIM. Here, we demonstrate that the expression of the mitochondrial creatine kinase MtCK linked to marker protein GFP (MtCK-GFP), which localizes to the space between the outer and the inner mitochondrial membrane, can be used as a cristae marker. Applying ExM on mitochondria labeled with this construct enables visualization of morphological changes of cristae and localization studies of mitochondrial proteins relative to cristae without the need for specialized setups. For the first time we present the combination of specific mitochondrial intermembrane space labeling and ExM as a tool for studying internal structure of mitochondria.},
  language  = {en}
}
@article{PalladinoChiocchettiFranketal.2020,
  author    = {Palladino, Viola Stella and Chiocchetti, Andreas G. and Frank, Lukas and Haslinger, Denise and McNeill, Rhiannon and Radtke, Franziska and Till, Andreas and Haupt, Simone and Br{\"u}stle, Oliver and G{\"u}nther, Katharina and Edenhofer, Frank and Hoffmann, Per and Reif, Andreas and Kittel-Schneider, Sarah},
  title     = {Energy metabolism disturbances in cell models of PARK2 CNV carriers with ADHD},
  series = {Journal of Clinical Medicine},
  volume    = {9},
  journal   = {Journal of Clinical Medicine},
  number    = {12},
  issn      = {2077-0383},
  doi       = {10.3390/jcm9124092},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-220074},
  year      = {2020},
  abstract  = {The main goal of the present study was the identification of cellular phenotypes in attention-deficit-/hyperactivity disorder (ADHD) patient-derived cellular models from carriers of rare copy number variants (CNVs) in the PARK2 locus that have been previously associated with ADHD. Human-derived fibroblasts (HDF) were cultured and human-induced pluripotent stem cells (hiPSC) were reprogrammed and differentiated into dopaminergic neuronal cells (mDANs). A series of assays in baseline condition and in different stress paradigms (nutrient deprivation, carbonyl cyanide m-chlorophenyl hydrazine (CCCP)) focusing on mitochondrial function and energy metabolism (ATP production, basal oxygen consumption rates, reactive oxygen species (ROS) abundance) were performed and changes in mitochondrial network morphology evaluated. We found changes in PARK2 CNV deletion and duplication carriers with ADHD in PARK2 gene and protein expression, ATP production and basal oxygen consumption rates compared to healthy and ADHD wildtype control cell lines, partly differing between HDF and mDANs and to some extent enhanced in stress paradigms. The generation of ROS was not influenced by the genotype. Our preliminary work suggests an energy impairment in HDF and mDAN cells of PARK2 CNV deletion and duplication carriers with ADHD. The energy impairment could be associated with the role of PARK2 dysregulation in mitochondrial dynamics.},
  language  = {en}
}
@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}
}
@article{SacchettoSequeiraBerteroetal.2019,
  author    = {Sacchetto, Claudia and Sequeira, Vasco and Bertero, Edoardo and Dudek, Jan and Maack, Christoph and Calore, Martina},
  title     = {Metabolic Alterations in Inherited Cardiomyopathies},
  series = {Journal of Clinical Medicine},
  volume    = {8},
  journal   = {Journal of Clinical Medicine},
  number    = {12},
  issn      = {2077-0383},
  doi       = {10.3390/jcm8122195},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193806},
  year      = {2019},
  abstract  = {The normal function of the heart relies on a series of complex metabolic processes orchestrating the proper generation and use of energy. In this context, mitochondria serve a crucial role as a platform for energy transduction by supplying ATP to the varying demand of cardiomyocytes, involving an intricate network of pathways regulating the metabolic flux of substrates. The failure of these processes results in structural and functional deficiencies of the cardiac muscle, including inherited cardiomyopathies. These genetic diseases are characterized by cardiac structural and functional anomalies in the absence of abnormal conditions that can explain the observed myocardial abnormality, and are frequently associated with heart failure. Since their original description, major advances have been achieved in the genetic and phenotype knowledge, highlighting the involvement of metabolic abnormalities in their pathogenesis. This review provides a brief overview of the role of mitochondria in the energy metabolism in the heart and focuses on metabolic abnormalities, mitochondrial dysfunction, and storage diseases associated with inherited cardiomyopathies.},
  language  = {en}
}
@article{BartelPeinPopperetal.2019,
  author    = {Bartel, Karin and Pein, Helmut and Popper, Bastian and Schmitt, Sabine and Janaki-Raman, Sudha and Schulze, Almut and Lengauer, Florian and Koeberle, Andreas and Werz, Oliver and Zischka, Hans and M{\"u}ller, Rolf and Vollmar, Angelika M. and Schwarzenberg, Karin von},
  title     = {Connecting lysosomes and mitochondria - a novel role for lipid metabolism in cancer cell death},
  series = {Cell Communication and Signaling},
  volume    = {17},
  journal   = {Cell Communication and Signaling},
  doi       = {10.1186/s12964-019-0399-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-221524},
  year      = {2019},
  abstract  = {Background The understanding of lysosomes has been expanded in recent research way beyond their view as cellular trash can. Lysosomes are pivotal in regulating metabolism, endocytosis and autophagy and are implicated in cancer. Recently it was discovered that the lysosomal V-ATPase, which is known to induce apoptosis, interferes with lipid metabolism in cancer, yet the interplay between these organelles is poorly understood. Methods LC-MS/MS analysis was performed to investigate lipid distribution in cells. Cell survival and signaling pathways were analyzed by means of cell biological methods (qPCR, Western Blot, flow cytometry, CellTiter-Blue). Mitochondrial structure was analyzed by confocal imaging and electron microscopy, their function was determined by flow cytometry and seahorse measurements. Results Our data reveal that interfering with lysosomal function changes composition and subcellular localization of triacylglycerids accompanied by an upregulation of PGC1α and PPARα expression, master regulators of energy and lipid metabolism. Furthermore, cardiolipin content is reduced driving mitochondria into fission, accompanied by a loss of membrane potential and reduction in oxidative capacity, which leads to a deregulation in cellular ROS and induction of mitochondria-driven apoptosis. Additionally, cells undergo a metabolic shift to glutamine dependency, correlated with the fission phenotype and sensitivity to lysosomal inhibition, most prominent in Ras mutated cells. Conclusion This study sheds mechanistic light on a largely uninvestigated triangle between lysosomes, lipid metabolism and mitochondrial function. Insight into this organelle crosstalk increases our understanding of mitochondria-driven cell death. Our findings furthermore provide a first hint on a connection of Ras pathway mutations and sensitivity towards lysosomal inhibitors.},
  language  = {en}
}
@article{RufBrantlWagener2018,
  author    = {Ruf, Dominik and Brantl, Victor and Wagener, Johannes},
  title     = {Mitochondrial Fragmentation in \(Aspergillus\) \(fumigatus\) as Early Marker of Granulocyte Killing Activity},
  series = {Frontiers in Cellular and Infection Microbiology},
  volume    = {8},
  journal   = {Frontiers in Cellular and Infection Microbiology},
  number    = {128},
  doi       = {10.3389/fcimb.2018.00128},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227133},
  year      = {2018},
  abstract  = {The host's defense against invasive mold infections relies on diverse antimicrobial activities of innate immune cells. However, studying these mechanisms in vitro is complicated by the filamentous nature of such pathogens that typically form long, branched, multinucleated and compartmentalized hyphae. Here we describe a novel method that allows for the visualization and quantification of the antifungal killing activity exerted by human granulocytes against hyphae of the opportunistic pathogen Aspergillus fumigatus. The approach relies on the distinct impact of fungal cell death on the morphology of mitochondria that were visualized with green fluorescent protein (GFP). We show that oxidative stress induces complete fragmentation of the tubular mitochondrial network which correlates with cell death of affected hyphae. Live cell microscopy revealed a similar and non-reversible disruption of the mitochondrial morphology followed by fading of fluorescence in Aspergillus hyphae that were killed by human granulocytes. Quantitative microscopic analysis of fixed samples was subsequently used to estimate the antifungal activity. By utilizing this assay, we demonstrate that lipopolysaccharides as well as human serum significantly increase the killing efficacy of the granulocytes. Our results demonstrate that evaluation of the mitochondrial morphology can be utilized to assess the fungicidal activity of granulocytes against A. fumigatus hyphae.},
  language  = {en}
}
@article{ChenLotzRoeweretal.2018,
  author    = {Chen, Shasha and Lotz, Christopher and Roewer, Norbert and Broscheit, Jens-Albert},
  title     = {Comparison of volatile anesthetic-induced preconditioning in cardiac and cerebral system: molecular mechanisms and clinical aspects},
  series = {European Journal of Medical Research},
  volume    = {23},
  journal   = {European Journal of Medical Research},
  number    = {10},
  doi       = {10.1186/s40001-018-0308-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175509},
  year      = {2018},
  abstract  = {Volatile anesthetic-induced preconditioning ( APC) has shown to have cardiac and cerebral protective properties in both pre-clinical models and clinical trials. Interestingly, accumulating evidences demonstrate that, except from some specific characters, the underlying molecular mechanisms of APC-induced protective effects in myocytes and neurons are very similar; they share several major intracellular signaling pathways, including mediating mitochondrial function, release of inflammatory cytokines and cell apoptosis. Among all the experimental results, cortical spreading depolarization is a relative newly discovered cellular mechanism of APC, which, however, just exists in central nervous system. Applying volatile anesthetic preconditioning to clinical practice seems to be a promising cardio- and neuroprotective strategy. In this review, we also summarized and discussed the results of recent clinical research of APC. Despite all the positive experimental evidences, large-scale, long-term, more precisely controlled clinical trials focusing on the perioperative use of volatile anesthetics for organ protection are still needed.},
  language  = {en}
}
@article{GoosDejungJanzenetal.2017,
  author    = {Goos, Carina and Dejung, Mario and Janzen, Christian J. and Butter, Falk and Kramer, Susanne},
  title     = {The nuclear proteome of Trypanosoma brucei},
  series = {PLoS ONE},
  volume    = {12},
  journal   = {PLoS ONE},
  number    = {7},
  doi       = {10.1371/journal.pone.0181884},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158572},
  pages     = {e0181884},
  year      = {2017},
  abstract  = {Trypanosoma brucei is a protozoan flagellate that is transmitted by tsetse flies into the mammalian bloodstream. The parasite has a huge impact on human health both directly by causing African sleeping sickness and indirectly, by infecting domestic cattle. The biology of trypanosomes involves some highly unusual, nuclear-localised processes. These include polycistronic transcription without classical promoters initiated from regions defined by histone variants, trans-splicing of all transcripts to the exon of a spliced leader RNA, transcription of some very abundant proteins by RNA polymerase I and antigenic variation, a switch in expression of the cell surface protein variants that allows the parasite to resist the immune system of its mammalian host. Here, we provide the nuclear proteome of procyclic Trypanosoma brucei, the stage that resides within the tsetse fly midgut. We have performed quantitative label-free mass spectrometry to score 764 significantly nuclear enriched proteins in comparison to whole cell lysates. A comparison with proteomes of several experimentally characterised nuclear and non-nuclear structures and pathways confirmed the high quality of the dataset: the proteome contains about 80\% of all nuclear proteins and less than 2\% false positives. Using motif enrichment, we found the amino acid sequence KRxR present in a large number of nuclear proteins. KRxR is a sub-motif of a classical eukaryotic monopartite nuclear localisation signal and could be responsible for nuclear localization of proteins in Kinetoplastida species. As a proof of principle, we have confirmed the nuclear localisation of six proteins with previously unknown localisation by expressing eYFP fusion proteins. While proteome data of several T. brucei organelles have been published, our nuclear proteome closes an important gap in knowledge to study trypanosome biology, in particular nuclear-related processes.},
  language  = {en}
}
@article{PrinzKaraciviStormannsetal.2015,
  author    = {Prinz, Johanna and Karacivi, Aylin and Stormanns, Eva R. and Recks, Masha S. and K{\"u}rten, Stefanie},
  title     = {Time-Dependent Progression of Demyelination and Axonal Pathology in MP4-Induced Experimental Autoimmune Encephalomyelitis},
  series = {PloS One},
  volume    = {10},
  journal   = {PloS One},
  number    = {12},
  doi       = {10.1371/journal.pone.0144847},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146651},
  pages     = {e0144847},
  year      = {2015},
  abstract  = {Background Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) characterized by inflammation, demyelination and axonal pathology. Myelin basic protein/proteolipid protein (MBP-PLP) fusion protein MP4 is capable of inducing chronic experimental autoimmune encephalomyelitis (EAE) in susceptible mouse strains mirroring diverse histopathological and immunological hallmarks of MS. Limited availability of human tissue underscores the importance of animal models to study the pathology of MS. Methods Twenty-two female C57BL/6 (B6) mice were immunized with MP4 and the clinical development of experimental autoimmune encephalomyelitis (EAE) was observed. Methylene blue-stained semi-thin and ultra-thin sections of the lumbar spinal cord were assessed at the peak of acute EAE, three months (chronic EAE) and six months after onset of EAE (long-term EAE). The extent of lesional area and inflammation were analyzed in semi-thin sections on a light microscopic level. The magnitude of demyelination and axonal damage were determined using electron microscopy. Emphasis was put on the ventrolateral tract (VLT) of the spinal cord. Results B6 mice demonstrated increasing demyelination and severe axonal pathology in the course of MP4-induced EAE. In addition, mitochondrial swelling and a decrease in the nearest neighbor neurofilament distance (NNND) as early signs of axonal damage were evident with the onset of EAE. In semi-thin sections we observed the maximum of lesional area in the chronic state of EAE while inflammation was found to a similar extent in acute and chronic EAE. In contrast to the well-established myelin oligodendrocyte glycoprotein (MOG) model, disease stages of MP4-induced EAE could not be distinguished by assessing the extent of parenchymal edema or the grade of inflammation. Conclusions Our results complement our previous ultrastructural studies of B6 EAE models and suggest that B6 mice immunized with different antigens constitute useful instruments to study the diverse histopathological aspects of MS.},
  language  = {en}
}
@article{MasicValenciaHernandezHazraetal.2015,
  author    = {Masic, Anita and Valencia Hernandez, Ana Maria and Hazra, Sudipta and Glaser, Jan and Holzgrabe, Ulrike and Hazra, Banasri and Schurigt, Uta},
  title     = {Cinnamic Acid Bornyl Ester Derivatives from Valeriana wallichii Exhibit Antileishmanial In Vivo Activity in Leishmania major-Infected BALB/c Mice},
  series = {PLoS One},
  volume    = {10},
  journal   = {PLoS One},
  number    = {11},
  doi       = {10.1371/journal.pone.0142386},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125354},
  pages     = {e0142386},
  year      = {2015},
  abstract  = {Human leishmaniasis covers a broad spectrum of clinical manifestations ranging from self-healing cutaneous leishmaniasis to severe and lethal visceral leishmaniasis caused among other species by Leishmania major or Leishmania donovani, respectively. Some drug candidates are in clinical trials to substitute current therapies, which are facing emerging drug-resistance accompanied with serious side effects. Here, two cinnamic acid bornyl ester derivatives (1 and 2) were assessed for their antileishmanial activity. Good selectivity and antileishmanial activity of bornyl 3-phenylpropanoate (2) in vitro prompted the antileishmanial assessment in vivo. For this purpose, BALB/c mice were infected with Leishmania major promastigotes and treated with three doses of 50 mg/kg/day of compound 2. The treatment prevented the characteristic swelling at the site of infection and correlated with reduced parasite burden. Transmitted light microscopy and transmission electron microscopy of Leishmania major promastigotes revealed that compounds 1 and 2 induce mitochondrial swelling. Subsequent studies on Leishmania major promastigotes showed the loss of mitochondrial transmembrane potential (ΔΨm) as a putative mode of action. As the cinnamic acid bornyl ester derivatives 1 and 2 had exhibited antileishmanial activity in vitro, and compound 2 in Leishmania major-infected BALB/c mice in vivo, they can be regarded as possible lead structures for the development of new antileishmanial therapeutic approaches.},
  language  = {en}
}
@article{OttDorschFraunholzetal.2015,
  author    = {Ott, Christine and Dorsch, Eva and Fraunholz, Martin and Straub, Sebastian and Kozjak-Pavlovic, Vera},
  title     = {Detailed Analysis of the Human Mitochondrial Contact Site Complex Indicate a Hierarchy of Subunits},
  series = {PLoS One},
  volume    = {10},
  journal   = {PLoS One},
  number    = {3},
  doi       = {10.1371/journal.pone.0120213},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125347},
  pages     = {e0120213},
  year      = {2015},
  abstract  = {Mitochondrial inner membrane folds into cristae, which significantly increase its surface and are important for mitochondrial function. The stability of cristae depends on the mitochondrial contact site (MICOS) complex. In human mitochondria, the inner membrane MICOS complex interacts with the outer membrane sorting and assembly machinery (SAM) complex, to form the mitochondrial intermembrane space bridging complex (MIB). We have created knockdown cell lines of most of the MICOS and MIB components and have used them to study the importance of the individual subunits for the cristae formation and complex stability. We show that the most important subunits of the MIB complex in human mitochondria are Mic60/Mitofilin, Mic19/CHCHD3 and an outer membrane component Sam50. We provide additional proof that ApoO indeed is a subunit of the MICOS and MIB complexes and propose the name Mic23 for this protein. According to our results, Mic25/CHCHD6, Mic27/ApoOL and Mic23/ApoO appear to be periphery subunits of the MICOS complex, because their depletion does not affect cristae morphology or stability of other components.},
  language  = {en}
}
@article{NiemannHuberWagneretal.2014,
  author    = {Niemann, Axel and Huber, Nina and Wagner, Konstanze M. and Somandin, Christian and Horn, Michael and Lebrun-Julien, Fr{\´e}d{\´e}ric and Angst, Brigitte and Pereira, Jorge A. and Halfter, Hartmut and Welzl, Hans and Feltri, M. Laura and Wrabetz, Lawrence and Young, Peter and Wessig, Carsten and Toyka, Klaus V. and Suter, Ueli},
  title     = {The Gdap1 knockout mouse mechanistically links redox control to Charcot-Marie-Tooth disease},
  series = {Brain},
  volume    = {137},
  journal   = {Brain},
  number    = {3},
  doi       = {10.1093/brain/awt371},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120731},
  pages     = {668-82},
  year      = {2014},
  abstract  = {The ganglioside-induced differentiation-associated protein 1 (GDAP1) is a mitochondrial fission factor and mutations in GDAP1 cause Charcot-Marie-Tooth disease. We found that Gdap1 knockout mice (\(Gdap1^{-/-}\)), mimicking genetic alterations of patients suffering from severe forms of Charcot-Marie-Tooth disease, develop an age-related, hypomyelinating peripheral neuropathy. Ablation of Gdap1 expression in Schwann cells recapitulates this phenotype. Additionally, intra-axonal mitochondria of peripheral neurons are larger in \(Gdap1^{-/-}\) mice and mitochondrial transport is impaired in cultured sensory neurons of \(Gdap1^{-/-}\) mice compared with controls. These changes in mitochondrial morphology and dynamics also influence mitochondrial biogenesis. We demonstrate that mitochondrial DNA biogenesis and content is increased in the peripheral nervous system but not in the central nervous system of \(Gdap1^{-/-}\) mice compared with control littermates. In search for a molecular mechanism we turned to the paralogue of GDAP1, GDAP1L1, which is mainly expressed in the unaffected central nervous system. GDAP1L1 responds to elevated levels of oxidized glutathione by translocating from the cytosol to mitochondria, where it inserts into the mitochondrial outer membrane. This translocation is necessary to substitute for loss of GDAP1 expression. Accordingly, more GDAP1L1 was associated with mitochondria in the spinal cord of aged \(Gdap1^{-/-}\) mice compared with controls. Our findings demonstrate that Charcot-Marie-Tooth disease caused by mutations in GDAP1 leads to mild, persistent oxidative stress in the peripheral nervous system, which can be compensated by GDAP1L1 in the unaffected central nervous system. We conclude that members of the GDAP1 family are responsive and protective against stress associated with increased levels of oxidized glutathione.},
  language  = {en}
}
@article{BoltzeKleinschnitzReymannetal.2012,
  author    = {Boltze, Johannes and Kleinschnitz, Christoph and Reymann, Klaus G. and Reiser, Georg and Wagner, Daniel-Christoph and Kranz, Alexander and Michalski, Dominik},
  title     = {Neurovascular pathophysiology in cerebral ischemia, dementia and the ageing brain - current trends in basic, translational and clinical research},
  series = {Experimental \& Translational Stroke Medicine},
  volume    = {4},
  journal   = {Experimental \& Translational Stroke Medicine},
  number    = {14},
  doi       = {doi:10.1186/2040-7378-4-14},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126679},
  year      = {2012},
  abstract  = {The 7th International Symposium on Neuroprotection and Neurorepair was held from May 2nd to May 5th, 2012 in Potsdam, Germany. The symposium, which directly continues the successful Magdeburg meeting series, attracted over 330 colleagues from 29 countries to discuss recent findings and advances in the field. The focus of the 2012 symposium was widened from stroke and traumatic brain injury to neurodegenerative diseases, notably dementia, and more generally the ageing brain. Thereby, emphasis was given on neurovascular aspects of neurodegeneration and stroke including the blood-brain barrier, recent findings regarding the pathomechanism of Alzheimer's disease, and brain imaging approaches. In addition, neurobiochemical aspects of neuroprotection, the role of astrogliosis, the clinical progress of cell-based approaches as well as translational hurdles and opportunities were discussed in-depth. This review summarizes some of the most stimulating discussions and reports from the meeting.},
  language  = {en}
}