Modeling abnormal early development with induced pluripotent stem cells from aneuploid syndromes

Abstract

Many human diseases share a developmental origin that manifests during childhood or maturity. Aneuploid syndromes are caused by supernumerary or reduced number of chromosomes and represent an extreme example of developmental disease, as they have devastating consequences before and after birth. Investigating how alterations in gene dosage drive these conditions is relevant because it might help treat some clinical aspects. It may also provide explanations as to how quantitative differences in gene expression determine phenotypic diversity and disease susceptibility among natural populations. Here, we aimed to produce induced pluripotent stem cell (iPSC) lines that can be used to improve our understanding of aneuploid syndromes. We have generated iPSCs from monosomy X [Turner syndrome (TS)], trisomy 8 (Warkany syndrome 2), trisomy 13 (Patau syndrome) and partial trisomy 11;22 (Emanuel syndrome), using either skin fibroblasts from affected individuals or amniocytes from antenatal diagnostic tests. These cell lines stably maintain the karyotype of the donors and behave like embryonic stem cells in all tested assays. TS iPSCs were used for further studies including global gene expression analysis and tissue-specific directed differentiation. Multiple clones displayed lower levels of the pseudoautosomal genes ASMTL and PPP2R3B than the controls. Moreover, they could be transformed into neural-like, hepatocyte-like and heart-like cells, but displayed insufficient up-regulation of the pseudoautosomal placental gene CSF2RA during embryoid body formation. These data support that abnormal organogenesis and early lethality in TS are not caused by a tissue-specific differentiation blockade, but rather involves other abnormalities including impaired placentation.

Human germ cell formation in xenotransplants of induced pluripotent stem cells carrying X chromosome aneuploidies

“…1F). This indicated that X chromosome aneuploidy does not affect reprogramming to pluripotency or differentiation into the three primary germ layers, similar to a previous report of iPSC-derived teratoma formation with Turner lines33.…”

The Eutherian Pseudoautosomal Region

“…Human stem cell studies suggest that pseudoautosomal and other XCI escaping genes may have an important role in placental functions and early development [Urbach and Benvenisty, 2009;Li et al, 2012;Bellott et al, 2014]. This explains the 70-99% lethality of non-mosaic 45,X human embryos [Urbach and Benvenisty, 2009;Berletch et al, 2010;Hook and Warburton, 2014] as well as the almost complete unviability of X monosomy in species with large PARs [Raudsepp et al, 2012].…”

Comparative Organization and Gene Expression Profiles of the Porcine Pseudoautosomal Region

“…Such discrimination might be important because recent studies in human embryonic and induced pluripotent stem cells show that functional diploidy for the PAR genes might be critical for normal embryonic development [Urbach and Benvenisty, 2009;Li et al, 2012]. That is why we carried out a pilot study profiling the expression of the PAR and X-specific genes in pigs.…”

“…Initial evidence for this was provided by the studies of human XX and XO embryonic stem cells showing that XO cells which are haploinsufficient for the PAR and other genes that escape X inactivation, are differentially expressed in placenta [Urbach and Benvenisty, 2009]. Very recently, another human study used induced pluripotent stem cells (iPSCs) from XO individuals to model abnormal early development [Li et al, 2012] and showed that cell lines derived from XO iPSCs display lower expression level of PAR genes than normal controls. Indirectly, these findings are supported by the observations that viable XO individuals can be found in species with small PARs (human, horse, mouse) but are rare or absent in species with large PARs (pig, cattle, dog, cat) [Raudsepp et al, 2012], as if haploinsufficiency for too many PAR genes causes embryonic lethality.…”

“…Additionally, the gene content of the PAR might also have an important role during development as evidenced by modeling abnormal early development using aneuploid embryonic [Urbach and Benvenisty, 2009] and induced pluripotent stem cells [Li et al, 2012] and by comparing the incidence of viable XO individuals across species with different PARs [Raudsepp et al, 2012]. Furthermore, because the PAR is a recombination hotspot [Filatov, 2004;Flaquer et al, 2008Flaquer et al, , 2009 and an elevated recombination rate has been associated with DNA methylation, it is possible that some PAR genes might be subject to genomic imprinting [Luedi et al, 2007;Sigurdsson et al, 2009].…”