Chromosomal instability increases after induction of neural phenotype by RA in EC cells.

<p>(A) The rate of chromosomal instability presented a 2-fold increase. The bars indicate mean ± S.E.M. of two independent assays, *p<0.05. (B) Analysis of relative DNA content demonstrated that neural cells (RA) presented less DNA than cells incubated with vehicle. RA, <i>all-trans</i> retinoic acid.</p

Neural differentiation in ES and iPS cells after RA treatment.

<p>(A) Schematic representation of protocol. (B) Immunofluorescence quantification confirmed commitment into neural progenitors (nestin) and young neurons (βIII-tubulin). The images correspond to ES-differentiated cells. The bars indicate mean ± S.E.M. of two independent assays, *p<0.05. ES, embryonic stem cells; iPS, induced pluripotent stem cells; RA, <i>all-trans</i> retinoic acid.</p

During neurogenesis, stem cells are prone to chromosome loss and micronuclei formation, which correlates with survivin downregulation.

<p>Neural aneuploidy may contribute to cell diversity within the CNS. CNS, central nervous system.</p

After RA treatment ES-derived neural cells exhibit loss of DNA content.

<p>(A) RA-treated EBs plated for 5 days are enriched in βIII-tubulin labeled young neurons forming a network with long processes. (B) Flow cytometry analysis of relative DNA content demonstrates decreased DNA content in cells expressing βIII-tubulin compared to cells negative for this marker. Data was expressed as the ratio of propidium iodide mean fluorescence intensity (MFI) of G0/G1 peak of positive cells in RA group to MFI of G0/G1 peak of unlabeled cells in vehicle group. The data refer to mean ± S.E.M. of four independent experiments, *p<0.1.</p

Hypoploidy is the main kind of aneuploidy in RA-NPCs.

<p>Upon (A) ES cells and (B) iPS cells differentiation with RA, the hypoploidy level increased, whereas hyperploidy level was not altered. The data refer to mean ± S.E.M. of three independent experiments, *p<0.05. ES, embryonic stem cells; iPS, induced pluripotent stem cells; RA-NPCs, neural progenitor cells derived from <i>all-trans</i> retinoic acid treatment.</p

RA induces aneuploidy increase in pluripotent stem cells but not in somatic cells.

<p>(A) Metaphase spreads of RA-NPCs derived from ES cells stained with DAPI. After RA-neural differentiation, the aneuploidy level increased in (B) ES and (C) iPS cells, while (D) mouse embryonic fibroblasts (MEF) exposed to RA did not present aneuploidy increase. The data refer to mean ± S.E.M. of three independent experiments, *p<0.05. ES, embryonic stem cells; iPS, induced pluripotent stem cells; NPCs, neural progenitor cells; RA, <i>all-trans</i> retinoic acid.</p

Reduced survivin expression in RA-treated pluripotent stem cells.

<p>(A) Survivin mRNA and (B) survivin protein were significantly reduced after RA treatment. For quantitative PCR, relative mRNA levels represent the amount of survivin mRNA compared to β-actin mRNA; for western blotting, relative survivin levels are compared to α-tubulin. Bars indicate mean ± S.E.M. of three independent assays, * p<0.1. Data were expressed as the ratio of the mean of RA to the mean of vehicle.</p

RA-treated stem cells do not necessarily undergo apoptosis.

<p>No difference in apoptosis between RA-NPCs and cells incubated with vehicle was observed in (A) EC cells or (B) ES cells. The bars indicate mean ± S.E.M. of three independent assays, *p<0.05. RA-NPCs, neural progenitor cells derived from <i>all-trans</i> retinoic acid treatment; EC, embryonal carcinoma cells; ES, embryonic stem cells.</p

Micronuclei formation increase in pluripotent ES and iPS cells after RA exposure.

<p>(A) Photomicrography of two daughter cells nuclei (arrowhead) and a micronucleus (arrow) detected by DAPI staining. (B) RA increased micronuclei formation in ES and iPS cells. Data was expressed as the ratio of the mean of RA to the mean of vehicle. Bars indicate mean ± S.E.M. of three independent assays, *p<0.05, #p<0.1. ES, embryonic stem cells; iPS, induced pluripotent stem cells; RA, <i>all-trans</i> retinoic acid.</p

Neural differentiation in EC cells after RA treatment.

<p>EC, embryonal carcinoma cells; RA, <i>all-trans</i> retinoic acid.</p