TY  - JOUR
A1  - Galetzka, Danuta
A1  - Hansmann, Tamara
A1  - El Hajj, Nady
A1  - Weis, Eva
A1  - Irmscher, Benjamin
A1  - Ludwig, Marco
A1  - Schneider-Rätzke, Brigitte
A1  - Kohlschmidt, Nicolai
A1  - Beyer, Vera
A1  - Bartsch, Oliver
A1  - Zechner, Ulrich
A1  - Spix, Claudia
A1  - Haaf, Thomas
T1  - Monozygotic twins discordant for constitutive BRCA1 promoter methylation, childhood cancer and secondary cancer
JF  - Epigenetics
N2  - We describe monozygotic twins discordant for childhood leukemia and secondary thyroid carcinoma. We used bisulfite pyrosequencing to compare the constitutive promoter methylation of BRCA1 and several other tumor suppressor genes in primary fibroblasts. The affected twin displayed an increased BRCA1 methylation (12%), compared with her sister (3%). Subsequent bisulfite plasmid sequencing demonstrated that 13% (6 of 47) BRCA1 alleles were fully methylated in the affected twin, whereas her sister displayed only single CpG errors without functional implications. This between-twin methylation difference was also found in irradiated fibroblasts and untreated saliva cells. The BRCA1 epimutation may have originated by an early somatic event in the affected twin: approximately 25% of her body cells derived from different embryonic cell lineages carry one epigenetically inactivated BRCA1 allele. This epimutation was associated with reduced basal protein levels and a higher induction of BRCA1 after DNA damage. In addition, we performed a genome-wide microarray analysis of both sisters and found several copy number variations, i.e., heterozygous deletion and reduced expression of the RSPO3 gene in the affected twin. This monozygotic twin pair represents an impressive example of epigenetic somatic mosaicism, suggesting a role for constitutive epimutations, maybe along with de novo genetic alterations in recurrent tumor development.
KW  - BRCA1
KW  - childhood cancer
KW  - DNA Methylation
KW  - epimutation
KW  - monozygotic twins
KW  - secondary cancer
KW  - somatic mosaicism
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125386
VL  - 7
IS  - 1
ER  - 
TY  - JOUR
A1  - Beyer, Felix
A1  - Jadasz, Janusz
A1  - Samper Agrelo, Iria
A1  - Schira‐Heinen, Jessica
A1  - Groh, Janos
A1  - Manousi, Anastasia
A1  - Bütermann, Christine
A1  - Estrada, Veronica
A1  - Reiche, Laura
A1  - Cantone, Martina
A1  - Vera, Julio
A1  - Viganò, Francesca
A1  - Dimou, Leda
A1  - Müller, Hans Werner
A1  - Hartung, Hans‐Peter
A1  - Küry, Patrick
T1  - Heterogeneous fate choice of genetically modulated adult neural stem cells in gray and white matter of the central nervous system
JF  - Glia
N2  - Apart from dedicated oligodendroglial progenitor cells, adult neural stem cells (aNSCs) can also give rise to new oligodendrocytes in the adult central nervous system (CNS). This process mainly confers myelinating glial cell replacement in pathological situations and can hence contribute to glial heterogeneity. Our previous studies demonstrated that the p57kip2 gene encodes an intrinsic regulator of glial fate acquisition and we here investigated to what degree its modulation can affect stem cell‐dependent oligodendrogenesis in different CNS environments. We therefore transplanted p57kip2 knockdown aNSCs into white and gray matter (WM and GM) regions of the mouse brain, into uninjured spinal cords as well as in the vicinity of spinal cord injuries and evaluated integration and differentiation in vivo. Our experiments revealed that under healthy conditions intrinsic suppression of p57kip2 as well as WM localization promote differentiation toward myelinating oligodendrocytes at the expense of astrocyte generation. Moreover, p57kip2 knockdown conferred a strong benefit on cell survival augmenting net oligodendrocyte generation. In the vicinity of hemisectioned spinal cords, the gene knockdown led to a similar induction of oligodendroglial features; however, newly generated oligodendrocytes appeared to suffer more from the hostile environment. This study contributes to our understanding of mechanisms of adult oligodendrogenesis and glial heterogeneity and further reveals critical factors when considering aNSC mediated cell replacement in injury and disease.
KW  - glial fate modulation
KW  - myelin
KW  - neural stem cell
KW  - p57kip2
KW  - regional heterogeneity
KW  - spinal cord injury
KW  - transplantation
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218566
VL  - 68
IS  - 2
SP  - 393
EP  - 406
ER  -