Neurogenic potential of human mesenchymal stem cells revisited: analysis by immunostaining, time-lapse video and microarray

Abstract

The possibility of generating neural cells from human bone-marrow-derived mesenchymal stem cells (hMSCs) by simple in vitro treatments is appealing both conceptually and practically. However, whether phenotypic modulations observed after chemical manipulation of such stem cells truly represent a genuine trans-lineage differentiation remains to be established. We have re-evaluated the effects of a frequently reported biochemical approach, based on treatment with butylated hydroxyanisole and dimethylsulphoxide, to bring about such phenotypic conversion by monitoring the morphological changes induced by the treatment in real time, by analysing the expression of phenotype-specific protein markers and by assessing the modulation of transcriptome. Video time-lapse microscopy showed that conversion of mesenchymal stem cells to a neuron-like morphology could be reproduced in normal primary fibroblasts as well as mimicked by addition of drugs eliciting cytoskeletal collapse and disruption of focal adhesion contacts. Analysis of markers revealed that mesenchymal stem cells constitutively expressed multi-lineage traits, including several pertaining to the neural one. However, the applied `neural induction' protocol neither significantly modulated the expression of such markers, nor induced de novo translation of other neural-specific proteins. Similarly, global expression profiling of over 21,000 genes demonstrated that gene transcription was poorly affected. Most strikingly, we found that the set of genes whose expression was altered by the inductive treatment did not match those sets of genes differentially expressed when comparing untreated mesenchymal stem cells and immature neural tissues. Conversely, by comparing these gene expression profiles with that obtained from comparisons between the same cells and an unrelated non-neural organ, such as liver, we found that the adopted neural induction protocol was no more effective in redirecting human mesenchymal stem cells toward a neural phenotype than toward an endodermal hepatic pathway.

Induced in vitro differentiation of neural-like cells from human exfoliated deciduous teeth-derived stem cells

“…Additionally, the duration of neural induction was relatively short. Furthermore, the morphology of differentiated cells did not initially change to mesenchymal cells by the replacement of differentiation medium with mesenchymal medium (data not shown) which may further confirm the neural identity of these cells, as previously stated (Bertani et al, 2005).…”

Transplantation of umbilical cord–derived mesenchymal stem cells as a novel strategy to protect the central nervous system: technical aspects, preclinical studies, and clinical perspectives

“…However, several neural cell-related mRNAs and proteins are also expressed by undifferentiated MSCs (75). Moreover, several studies have shown that in vitro neuronal differentiation protocols using chemical induction medium can produce unexpected and misleading effects, such as changes in cell morphology due to actin cytoskeleton disruption, cell shrinkage, or toxicity (76)(77)(78)(79) and the transient upregulation of neural markers without the induction of neural differentiation (80). These reports indicate the need for a more cautious evaluation of MSC differentiation that distinguishes between molecular signaling and lineage commitment steps to reliably assess the ability of MSCs to differentiate into neural cells.…”

Inducible Expression of Chimeric EWS/ETS Proteins Confers Ewing's Family Tumor-Like Phenotypes to Human Mesenchymal Progenitor Cells

“…Notably, the expression of CD54 (intercellular cell adhesion molecule-1 [ICAM1]), CD117 (c-kit), and CD271 (low-affinity nerve growth factor receptor [LNGFR]) increased in EWS/ETS-expressing UET-13 cells. These markers are positive in EFT cell lines (17,28,33), and in addition, CD117 is detected in about 40% of patient samples (17) and is negative in human primary MPCs (4,43). Thus, it is reasonable to consider that a phenotypic marker of EFT was induced in UET-13 cells by EWS/ETS expression.…”