TY  - JOUR
A1  - Varagnolo, Linda
A1  - Lin, Quiong
A1  - Obier, Nadine
A1  - Plass, Christoph
A1  - Dietl, Johannes
A1  - Zenke, Martin
A1  - Claus, Rainer
A1  - Müller, Albrecht M.
T1  - PRC2 inhibition counteracts the culture-associated loss of engraftment potential of human cord blood-derived hematopoietic stem and progenitor cells
JF  - Scientific Reports
N2  - Cord blood hematopoietic stem cells (CB-HSCs) are an outstanding source for transplantation approaches. However, the amount of cells per donor is limited and culture expansion of CB-HSCs is accompanied by a loss of engraftment potential. In order to analyze the molecular mechanisms leading to this impaired potential we profiled global and local epigenotypes during the expansion of human CB hematopoietic stem and progenitor cells (HPSCs). Human CB-derived CD34+ cells were cultured in serum-free medium together with SCF, TPO, FGF, with or without Igfbp2 and Angptl5 (STF/STFIA cocktails). As compared to the STF cocktail, the STFIA cocktail maintains in vivo repopulation capacity of cultured CD34+ cells. Upon expansion, CD34+ cells genome-wide remodel their epigenotype and depending on the cytokine cocktail, cells show different HK4me3 and H3K27me3 levels. Expanding cells without Igfbp2 and Angptl5 leads to higher global H3K27me3 levels. ChIPseq analyses reveal a cytokine cocktail-dependent redistribution of H3K27me3 profiles. Inhibition of the PRC2 component EZH2 counteracts the culture-associated loss of NOD scid gamma (NSG) engraftment potential. Collectively, our data reveal chromatin dynamics that underlie the culture-associated loss of engraftment potential. We identify PRC2 component EZH2 as being involved in the loss of engraftment potential during the in vitro expansion of HPSCs.
KW  - ex vivo expansion
KW  - epigenomic landscapes
KW  - in vivo polycomb
KW  - transplantation states genes
KW  - EZH2 differentiation trichostatin
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148374
VL  - 5
IS  - 12319
ER  - 
TY  - JOUR
A1  - Ahmad, Ruhel
A1  - Wolber, Wanja
A1  - Eckardt, Sigrid
A1  - Koch, Philipp
A1  - Schmitt, Jessica
A1  - Semechkin, Ruslan
A1  - Geis, Christian
A1  - Heckmann, Manfred
A1  - Brüstle, Oliver
A1  - McLaughlin, John K.
A1  - Sirén, Anna-Leena
A1  - Müller, Albrecht M.
T1  - Functional Neuronal Cells Generated by Human Parthenogenetic Stem Cells
JF  - PLoS One
N2  - Parent of origin imprints on the genome have been implicated in the regulation of neural cell type differentiation. The ability of human parthenogenetic (PG) embryonic stem cells (hpESCs) to undergo neural lineage and cell type-specific differentiation is undefined. We determined the potential of hpESCs to differentiate into various neural subtypes. Concurrently, we examined DNA methylation and expression status of imprinted genes. Under culture conditions promoting neural differentiation, hpESC-derived neural stem cells (hpNSCs) gave rise to glia and neuron-like cells that expressed subtype-specific markers and generated action potentials. Analysis of imprinting in hpESCs and in hpNSCs revealed that maternal-specific gene expression patterns and imprinting marks were generally maintained in PG cells upon differentiation. Our results demonstrate that despite the lack of a paternal genome, hpESCs generate proliferating NSCs that are capable of differentiation into physiologically functional neuron-like cells and maintain allele-specific expression of imprinted genes. Thus, hpESCs can serve as a model to study the role of maternal and paternal genomes in neural development and to better understand imprinting-associated brain diseases.
KW  - methylation
KW  - derivation
KW  - blastocysts
KW  - pluripotent
KW  - differentiation
KW  - lines
KW  - brain development
KW  - in-vitro
KW  - mice
KW  - specification
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130268
VL  - 7
IS  - 8
ER  -