References of "Smeets, Hubert J. M"
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See detailReplication Errors Made During Oogenesis Lead to Detectable De Novo mtDNA Mutations in Zebrafish Oocytes with a Low mtDNA Copy Number.
Otten, Auke B. C.; Stassen, Alphons P. M.; Adriaens, Michiel et al

in Genetics (2016), 204(4), 1423-1431

Of all pathogenic mitochondrial DNA (mtDNA) mutations in humans, ~25% is de novo, although the occurrence in oocytes has never been directly assessed. We used next generation sequencing to detect point ... [more ▼]

Of all pathogenic mitochondrial DNA (mtDNA) mutations in humans, ~25% is de novo, although the occurrence in oocytes has never been directly assessed. We used next generation sequencing to detect point mutations directly in the mtDNA of 3-15 individual mature oocytes and three somatic tissues from eight zebrafish females. Various statistical and biological filters allowed reliable detection of de novo variants with heteroplasmy >/=1.5%. In total, we detected 38 de novo base substitutions, but no insertions or deletions. These 38 de novo mutations were present in 19 of 103 mature oocytes, indicating that ~20% of the mature oocytes carry at least one de novo mutation with heteroplasmy >/=1.5%. This frequency of de novo mutations is close to that deducted from the reported error rate of polymerase gamma, the mitochondrial replication enzyme, implying that mtDNA replication errors made during oogenesis are a likely explanation. Substantial variation in the mutation prevalence among mature oocytes can be explained by the highly variable mtDNA copy number, since we previously reported that ~20% of the primordial germ cells have a mtDNA copy number of </=73 and would lead to detectable mutation loads. In conclusion, replication errors made during oogenesis are an important source of de novo mtDNA base substitutions and their location and heteroplasmy level determine their significance. [less ▲]

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See detailMyelin-Derived Lipids Modulate Macrophage Activity by Liver X Receptor Activation
Bogie, Jeroen F. J.; Timmermans, Silke; Huynh-Thu, Vân Anh ULg et al

in PLoS ONE (2012), 7(9), 44998

Multiple sclerosis is a chronic, inflammatory, demyelinating disease of the central nervous system in which macrophages and microglia play a central role. Foamy macrophages and microglia, containing ... [more ▼]

Multiple sclerosis is a chronic, inflammatory, demyelinating disease of the central nervous system in which macrophages and microglia play a central role. Foamy macrophages and microglia, containing degenerated myelin, are abundantly found in active multiple sclerosis lesions. Recent studies have described an altered macrophage phenotype after myelin internalization. However, it is unclear by which mechanisms myelin affects the phenotype of macrophages and how this phenotype can influence lesion progression. Here we demonstrate, by using genome wide gene expression analysis, that myelin-phagocytosing macrophages have an enhanced expression of genes involved in migration, phagocytosis and inflammation. Interestingly, myelin internalization also induced the expression of genes involved in liver-X-receptor signaling and cholesterol efflux. In vitro validation shows that myelin-phagocytosing macrophages indeed have an increased capacity to dispose intracellular cholesterol. In addition, myelin suppresses the secretion of the pro-inflammatory mediator IL-6 by macrophages, which was mediated by activation of liver-X-receptor b. Our data show that myelin modulates the phenotype of macrophages by nuclear receptor activation, which may subsequently affect lesion progression in demyelinating diseases such as multiple sclerosis. [less ▲]

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