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- Götz, Alexandra, et al.
(författare)
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Exome sequencing identifies mitochondrial alanyl-tRNA synthetase mutations in infantile mitochondrial cardiomyopathy
- 2011
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Ingår i: American Journal of Human Genetics. - : Cell Press. - 0002-9297 .- 1537-6605. ; 88:5, s. 635-642
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Tidskriftsartikel (refereegranskat)abstract
- Infantile cardiomyopathies are devastating fatal disorders of the neonatal period or the first year of life. Mitochondrial dysfunction is a common cause of this group of diseases, but the underlying gene defects have been characterized in only a minority of cases, because tissue specificity of the manifestation hampers functional cloning and the heterogeneity of causative factors hinders collection of informative family materials. We sequenced the exome of a patient who died at the age of 10 months of hypertrophic mitochondrial cardiomyopathy with combined cardiac respiratory chain complex I and IV deficiency. Rigorous data analysis allowed us to identify a homozygous missense mutation in AARS2, which we showed to encode the mitochondrial alanyl-tRNA synthetase (mtAlaRS). Two siblings from another family, both of whom died perinatally of hypertrophic cardiomyopathy, had the same mutation, compound heterozygous with another missense mutation. Protein structure modeling of mtAlaRS suggested that one of the mutations affected a unique tRNA recognition site in the editing domain, leading to incorrect tRNA aminoacylation, whereas the second mutation severely disturbed the catalytic function, preventing tRNA aminoacylation. We show here that mutations in AARS2 cause perinatal or infantile cardiomyopathy with near-total combined mitochondrial respiratory chain deficiency in the heart. Our results indicate that exome sequencing is a powerful tool for identifying mutations in single patients and allows recognition of the genetic background in single-gene disorders of variable clinical manifestation and tissue-specific disease. Furthermore, we show that mitochondrial disorders extend to prenatal life and are an important cause of early infantile cardiac failure.
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| 4. |
- Sutinen, Elina M., et al.
(författare)
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Interleukin-18 alters protein expressions of neurodegenerative diseases-linked proteins in human SH-SY5Y neuron-like cells
- 2014
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Ingår i: Frontiers in Cellular Neuroscience. - : Frontiers Media SA. - 1662-5102. ; 8, s. 214-
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Tidskriftsartikel (refereegranskat)abstract
- Chronic inflammation and oxidative stress (OS) are present in Alzheimer's disease (AD) brains in addition to neuronal loss, Amyloid-beta (A beta) plaques and hyperphosphorylated tau-protein neurofibrillary tangles (NFTs). Previously we showed that levels of the pro-inflammatory cytokine, interleukin-18 (IL-18), are elevated in post-mortem AD brains. IL-18 can modulate the tau kinases, Cdk5 and GSK3?, as well as A beta-production. IL-18 levels are also increased in AD risk diseases, including type-2 diabetes and obesity. Here, we explored other IL-18 regulated proteins in neuron-like SH-SY5Y cells. Differentiated SH-SY5Y cells, incubated with IL-18 for 24, 48, or 72 h, were analyzed by two-dimensional gel electrophoresis (2D-DIGE). Specific altered protein spots were chosen and identified with mass spectrometry (MS) and verified by western immunoblotting (WIB). IL-18 had time-dependent effects on the SH-SY5Y proteome, modulating numerous protein levels/modifications. We concentrated on those related to OS (DDAH2, peroxiredoxins 2, 3, and 6, DJ-1, BLVRA), A beta-degradation (MMP14, TIMP2), A beta-aggregation (Septin-2), and modifications of axon growth and guidance associated, collapsin response mediator protein 2 (CRMP2). IL-18 significantly increased antioxidative enzymes, indicative of OS, and altered levels of glycolytic beta- and alpha-enolase and multifunctional 14-3-3 beta and -beta, commonly affected in neurodegenerative diseases. MMP14, TIMP2, alpha-enolase and 14-3-3 beta, indirectly involved in A? metabolism, as well as Septin-2 showed changes that increase A? levels. Increased 14-3-3 beta may contribute to GSK3 beta driven tau hyperphosphorylation and CRMP2 Thr514 and Ser522 phosphorylation with the Thr555-site, a target for Rho kinase, showing time-dependent changes. IL-18 also increased caspase-1 levels and vacuolization of the cells. Although our SH-SY5Y cells were not aged, as neurons in AD, our work suggests that heightened or prolonged IL-18 levels can drive protein changes of known relevance to AD pathogenesis.
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