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Mutations in NDUFB10 result in isolated complex I deficiency due to incomplete assembly of complex I holoenzyme
S26
Abstracts
dinucleotide (FAD), which is an essential cofactor of e.g. pyruvate dehydrogenase, succinate dehydrogenase, electron transferring flavoprotein dehydrogenase (ETFDH) and many different ETFDH dependent dehydrogenases involved in fatty acid oxidation and branched chain- amino acid metabolism. During these ongoing investigations, we measured the concentrations of riboflavin, FMN, and FAD in different tissues and the distribution in subcellular compartments in patient and control samples. Further functional studies are on the way to elucidate the disease mechanism. Our results point to the importance of exogenous supplementation with cofactor (or vitamin), which can compensate for deficiencies in cofactor biosynthesis/availability. doi:10.1016/j.mito.2015.07.074
Abstract 63 Mutations in NDUFB10 result in isolated complex I deficiency due to incomplete assembly of complex I holoenzyme Presenter: Marisa W. Friederich Marisa W. Friedericha, Curtis R. CoughlinIIa, Courtney O'Rourkea, Mark A. Lovellb, Katherine Gowanc, Johan L.K. Van Hovea a Dept. of Pediatrics, University of Colorado, Aurora, CO 80045, USA b Department of Pathology, University of Colorado, Aurora, CO 80045, USA c Department of Biochemistry and Molecular Genetics, University of Colorado, Aurora 80045, USA Body of Abstract: Isolated complex I deficiency is a major cause of respiratory chain enzyme disorders. Deficiencies can result from mutations that affect the catalytic activity of the enzyme or that impair the assembly or the stability of the complex I holoenzyme. A female infant presented with fatal neonatal overwhelming lactic acidosis and cardiomyopathy. Respiratory chain enzyme analysis and BNPage with in-gel activity staining showed decreased activity of complex I in both muscle and liver; however, complex I activity was normal in skin fibroblasts. Exome sequencing revealed compound heterozygous mutations in the NDUFB10 gene consisting of a frameshift and a missense mutation affecting a conserved amino acid. The NDUFB10 gene product is a structural protein of complex I located in its membrane arm. The amount of NDUFB10 protein was strongly reduced in muscle, less so in liver, and only mildly reduced in skin fibroblasts on Western blot analysis. Analysis of the assembly of complex I using Western blotting with an antibody against NDUFS2, a component of the earliest assembly, identified five intermediates of complex I including the large 900 kDa intermediate in the patient muscle and liver and to a much lesser extent in skin fibroblast. This analysis indicates that the assembly of complex I holoenzyme is perturbed at a late stage. Mutations in NDUFB10 are a novel cause of complex I deficiency due to disturbed assembly with tissue specific differences in the expression of this deficiency.
doi:10.1016/j.mito.2015.07.075
Abstract 64 Characterizing the human mitochondrial proteome using a genome-wide functional linkage network Hadi Zarkooba, Peidong Shena, Gregory M. Ennsb, Chiara Sabattic, Curt Scharfea a Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304, USA b Department of Pediatrics, Stanford University, Stanford, CA 94305, USA
c
Department of Health Research and Policy, Stanford University, Stanford, CA 94305, USA Abstract: Defects in nuclear-encoded mitochondrial proteins underlie a large number of debilitating hereditary conditions. Many of these diseases display clinical heterogeneity, which is thought to be an effect of the complex interplay between the mitochondrial proteome and the various metabolic pathways that converge in this organelle. Here we utilize a genome-wide functional linkage network (gFLN) to study the global properties of the mitochondrial proteome, to gain insights into the sub-organellar localization and function of individual mitochondrial proteins, and identify candidate genes for mitochondrial diseases. Our analysis focused on three principal levels including the study of the entire mitochondrial proteome, the mitochondrial sub-organellar compartments, and mitochondrial protein complexes. Utilizing the gFLN we identified a large gene, fully-connected subnetwork, which consisted entirely of known mitochondrial genes (termed mitochondrial FLN, mFLN). A structural analysis identified eight statistically significant gene network clusters in the mFLN, where each of the clusters was enriched for one of the four major sub-mitochondrial compartments of matrix, inner-membrane, inter-membrane space or outer-membrane. We used this analysis to predict the sub-mitochondrial localization of mitochondrial proteins to mFLN clusters, including genes that were not previously assigned to a specific compartment. We then expanded the mFLN by identifying mitochondrial candidate genes with high-probability interactions to this network. Integrative analysis of our network-based predictions with eight other functional mitochondrial datasets resulted in a high-probability set of 1094 human mitochondrial proteins. Several of the novel mitochondrial proteins predicted in this analysis were recently detected in an experimental method based on enzyme-tagging. Finally, we focused our analysis on mitochondrial respiratory chain complexes (RCC), which play a central role in mitochondrial function and disease. Analysis of the gFLN in the gene-functional neighborhood of RCC predicted several candidate genes with strong associations to RCC, including CISD1, SERF1A and NARF. Theses genes can serve as candidate genes for RCC-related diseases including Leigh syndrome.
doi:10.1016/j.mito.2015.07.076
Abstract 65 Mitochondrial disease patients' perception of dietary supplements' use Presenter: Amel Karaa Amel Karaaa,b, Joshua Kriegerc, Amy Holbertd, Johnston Grierc, John L.P. Thompsonc, Sumit Parikhe, Michio Hiranof a Massachusetts General Hospital, Boston MA 02114, USA b Harvard University, USA c Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY 10032, USA d University of South Florida, Tampa, FL, USA e Department of Neurology, Cleveland Clinic, Cleveland, OH, USA f Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA Abstract: Mitochondrial disease physicians' surveys through the Mitochondrial Medicine Society have shown that virtually all providers recommend a variety of dietary supplements to their patients. In this survey, we asked patients and parents of patients about their experience taking these dietary supplements as part of their treatment for mitochondrial disease. The survey was disseminated through the North American Mitochondrial Disease Consortium (NAMDC) and the Rare Disease Clinical Research Network (RDCRN) registries. The study
Abstracts
dinucleotide (FAD), which is an essential cofactor of e.g. pyruvate dehydrogenase, succinate dehydrogenase, electron transferring flavoprotein dehydrogenase (ETFDH) and many different ETFDH dependent dehydrogenases involved in fatty acid oxidation and branched chain- amino acid metabolism. During these ongoing investigations, we measured the concentrations of riboflavin, FMN, and FAD in different tissues and the distribution in subcellular compartments in patient and control samples. Further functional studies are on the way to elucidate the disease mechanism. Our results point to the importance of exogenous supplementation with cofactor (or vitamin), which can compensate for deficiencies in cofactor biosynthesis/availability. doi:10.1016/j.mito.2015.07.074
Abstract 63 Mutations in NDUFB10 result in isolated complex I deficiency due to incomplete assembly of complex I holoenzyme Presenter: Marisa W. Friederich Marisa W. Friedericha, Curtis R. CoughlinIIa, Courtney O'Rourkea, Mark A. Lovellb, Katherine Gowanc, Johan L.K. Van Hovea a Dept. of Pediatrics, University of Colorado, Aurora, CO 80045, USA b Department of Pathology, University of Colorado, Aurora, CO 80045, USA c Department of Biochemistry and Molecular Genetics, University of Colorado, Aurora 80045, USA Body of Abstract: Isolated complex I deficiency is a major cause of respiratory chain enzyme disorders. Deficiencies can result from mutations that affect the catalytic activity of the enzyme or that impair the assembly or the stability of the complex I holoenzyme. A female infant presented with fatal neonatal overwhelming lactic acidosis and cardiomyopathy. Respiratory chain enzyme analysis and BNPage with in-gel activity staining showed decreased activity of complex I in both muscle and liver; however, complex I activity was normal in skin fibroblasts. Exome sequencing revealed compound heterozygous mutations in the NDUFB10 gene consisting of a frameshift and a missense mutation affecting a conserved amino acid. The NDUFB10 gene product is a structural protein of complex I located in its membrane arm. The amount of NDUFB10 protein was strongly reduced in muscle, less so in liver, and only mildly reduced in skin fibroblasts on Western blot analysis. Analysis of the assembly of complex I using Western blotting with an antibody against NDUFS2, a component of the earliest assembly, identified five intermediates of complex I including the large 900 kDa intermediate in the patient muscle and liver and to a much lesser extent in skin fibroblast. This analysis indicates that the assembly of complex I holoenzyme is perturbed at a late stage. Mutations in NDUFB10 are a novel cause of complex I deficiency due to disturbed assembly with tissue specific differences in the expression of this deficiency.
doi:10.1016/j.mito.2015.07.075
Abstract 64 Characterizing the human mitochondrial proteome using a genome-wide functional linkage network Hadi Zarkooba, Peidong Shena, Gregory M. Ennsb, Chiara Sabattic, Curt Scharfea a Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304, USA b Department of Pediatrics, Stanford University, Stanford, CA 94305, USA
c
Department of Health Research and Policy, Stanford University, Stanford, CA 94305, USA Abstract: Defects in nuclear-encoded mitochondrial proteins underlie a large number of debilitating hereditary conditions. Many of these diseases display clinical heterogeneity, which is thought to be an effect of the complex interplay between the mitochondrial proteome and the various metabolic pathways that converge in this organelle. Here we utilize a genome-wide functional linkage network (gFLN) to study the global properties of the mitochondrial proteome, to gain insights into the sub-organellar localization and function of individual mitochondrial proteins, and identify candidate genes for mitochondrial diseases. Our analysis focused on three principal levels including the study of the entire mitochondrial proteome, the mitochondrial sub-organellar compartments, and mitochondrial protein complexes. Utilizing the gFLN we identified a large gene, fully-connected subnetwork, which consisted entirely of known mitochondrial genes (termed mitochondrial FLN, mFLN). A structural analysis identified eight statistically significant gene network clusters in the mFLN, where each of the clusters was enriched for one of the four major sub-mitochondrial compartments of matrix, inner-membrane, inter-membrane space or outer-membrane. We used this analysis to predict the sub-mitochondrial localization of mitochondrial proteins to mFLN clusters, including genes that were not previously assigned to a specific compartment. We then expanded the mFLN by identifying mitochondrial candidate genes with high-probability interactions to this network. Integrative analysis of our network-based predictions with eight other functional mitochondrial datasets resulted in a high-probability set of 1094 human mitochondrial proteins. Several of the novel mitochondrial proteins predicted in this analysis were recently detected in an experimental method based on enzyme-tagging. Finally, we focused our analysis on mitochondrial respiratory chain complexes (RCC), which play a central role in mitochondrial function and disease. Analysis of the gFLN in the gene-functional neighborhood of RCC predicted several candidate genes with strong associations to RCC, including CISD1, SERF1A and NARF. Theses genes can serve as candidate genes for RCC-related diseases including Leigh syndrome.
doi:10.1016/j.mito.2015.07.076
Abstract 65 Mitochondrial disease patients' perception of dietary supplements' use Presenter: Amel Karaa Amel Karaaa,b, Joshua Kriegerc, Amy Holbertd, Johnston Grierc, John L.P. Thompsonc, Sumit Parikhe, Michio Hiranof a Massachusetts General Hospital, Boston MA 02114, USA b Harvard University, USA c Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY 10032, USA d University of South Florida, Tampa, FL, USA e Department of Neurology, Cleveland Clinic, Cleveland, OH, USA f Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA Abstract: Mitochondrial disease physicians' surveys through the Mitochondrial Medicine Society have shown that virtually all providers recommend a variety of dietary supplements to their patients. In this survey, we asked patients and parents of patients about their experience taking these dietary supplements as part of their treatment for mitochondrial disease. The survey was disseminated through the North American Mitochondrial Disease Consortium (NAMDC) and the Rare Disease Clinical Research Network (RDCRN) registries. The study