New potential sources of stem cells for clinical application include bone marrow mesenchymal stem cells (BMMSCs), human embryonic stem cells (hESCs), and induced pluripotent stem cells (iPS). However, each source is not without its own concerns. While research continues in an effort to overcome these problems, the generation of mesenchymal progenitors from existing hESC lines may circumvent many of these issues. We report here a simple and efficient method of generating hESC-derived mesenchymal progenitors (EMPs) and transcriptome profiling using a concise, custom-designed, oligomnucleotide gene expression microarray. Characterization of EMPs shows that these cells are similar to BMMSCs in terms of differentiation capacity as well as cell surface marker expression. In addition, EMPs express several ESC markers and HLA-G, a nonclassical MHC class I molecule with immunomodulatory properties. Morevoer, EMPs possess significantly enhanced proliferative ability over BMMSCs during which karyotypic stability was maintained. Although derived from hESCs, EMPs do not form any tumors in immunocompromised mice. To efficiently profile gene expression in multiple samples, we designed an oligoarray to probe just over 11,000 genes highly expressed in stem cells. We found that the transcriptome of EMPs is more similar to BMMSCs than hESCs. Both cell types highly express genes involved in processes related to the cytoskeleton, extracellular matrix, and cell adhesion, but EMPs show higher expression of genes involved in cell proliferation whereas BMMSCs showed higher expression of immune-related genes. Based on our data, EMPs may be an accessible source of mesenchymal progenitor for therapeutic use.
"For instance, HLA-G and HLA-E are non-classical MHC class Ib molecules that are essential in the acceptance of an embryo. To investigate whether PSCs also take advantage of these molecules, a study conducted by Yen et al. revealed that hESC-derived mesenchymal progenitor cells (MPCs) were resistant to NK cell lysis, coinciding with high HLA-G expression on the surface . Furthermore, several reports claimed that this resistance to NK cell cytotoxicity exists, by showing contradicting results in NKG2D ligand expression. "
[Show abstract][Hide abstract] ABSTRACT: One aim of stem cell-based therapy is to utilize pluripotent stem cells (PSCs) as a supplementary source of cells
to repair or replace tissues or organs that have ceased to function due to severe tissue damage. However, PSC-based therapy
requires extensive research to ascertain if PSC derivatives are functional without the risk of tumorigenicity, and also
do not engender severe immune rejection that threatens graft survival and function. Recently, the suitability of induced
pluripotent stem cells applied for patient-tailored cell therapy has been questioned since the discovery of several genetic
and epigenetic aberrations during the reprogramming process. Hence, it is crucial to understand the effect of these abnormalities
on the immunogenicity and survival of PSC grafts. As induced PSC-based therapy represents a hallmark for the
potential solution to prevent and arrest immune rejection, this review also summarizes several up-to-date key findings in
Current Stem Cell Research & Therapy 10/2013; 9(1). DOI:10.2174/1574888X113086660068 · 2.21 Impact Factor
"Most MSCs derivations are achieved via the formation of three-dimensional embryoid bodies, which are laborious, inefficient and uncontrollable for spontaneous differentiation14. Yen et al. have described a simple method of differentiating human ES cells (hESCs) into MSCs by switching hES cells from ES medium to defined medium, which consisted of DMEM-low glucose, 10% FBS, and 1% Penicillin/Streptomycin, followed by trypsinization-based passaging15. In this study, we investigated whether this method can be applied to human iPS cells. "
[Show abstract][Hide abstract] ABSTRACT: We describe a simple method for bone engineering using biodegradable scaffolds with mesenchymal stem cells derived from human induced-pluripotent stem cells (hiPS-MSCs). The hiPS-MSCs expressed mesenchymal markers (CD90, CD73, and CD105), possessed multipotency characterized by tri-lineages differentiation: osteogenic, adipogenic, and chondrogenic, and lost pluripotency - as seen with the loss of markers OCT3/4 and TRA-1-81 - and tumorigenicity. However, these iPS-MSCs are still positive for marker NANOG. We further explored the osteogenic potential of the hiPS-MSCs in synthetic polymer polycaprolactone (PCL) scaffolds or PCL scaffolds functionalized with natural polymer hyaluronan and ceramic TCP (PHT) both in vitro and in vivo. Our results showed that these iPS-MSCs are functionally compatible with the two 3D scaffolds tested and formed typically calcified structure in the scaffolds. Overall, our results suggest the iPS-MSCs derived by this simple method retain fully osteogenic function and provide a new solution towards personalized orthopedic therapy in the future.
[Show abstract][Hide abstract] ABSTRACT: 3-dimensional microcarrier (3D-MC) cell culture systems are often used for expansion of stem cells including mesenchymal stem cells (MSCs) for high cell volumes required in clinical applications. However, compared to 2-dimensional (2D) cell culture, effects of 3D-MC systems on MSC differentiation have not been well studied. In this study, the behavior of various sources of MSCs from two species was observed and compared on 3D collagen I-coated-MCs (COL-MC) versus 2D culture. Proliferation of all MSCs cultured on 3D COL-MC was much decreased compared to 2D culture. Unexpectedly, COL-MC-cultured MSCs underwent spontaneous osteogenesis without exogenous addition of biochemical factors, as evidenced by increased osteogenic genes expression, ALP activity, calcium deposition, and collagen I secretion. Furthermore, MSCs cultured on 3D-MC alone without collagen I coating is sufficient to induce osteogenesis. The spontaneous lineage commitment induced by 3D-MC culture was mediated by increased cytoskeletal tension and actomyosin contraction of MSCs, which could be prevented by latrunculin B and blebbistatin, inhibitors of cytoskeletal tension and actomyosin contraction respectively. Our findings show that the combination of bioengineered MC and MSCs alone can induce specific lineage commitment very efficiently. These data have strong implications in simplifying tissue engineering strategies for therapeutic applications.
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