Low Osteogenic Differentiation Potential of Placenta-Derived Mesenchymal Stromal Cells Correlates with Low Expression of the Transcription Factors Runx2 and Twist2

Abstract

Recent studies indicated that mesenchymal stromal cells from bone marrow (bmMSC) differ in their osteogenic differentiation capacity compared to MSC from term placenta (pMSC). We extended these studies and investigated the expression of factors involved in regulation of bone metabolism in both cell types. To this end, MSC were expanded in vitro and characterized. The total transcriptome was investigated by microarrays, and for selected genes, the differences in gene expression were explored by quantitative reverse transcriptasepolymerase chain reaction, immunocytochemistry, and flow cytometry. We report that bmMSC and pMSC share expression of typical lineage surface markers, including CD73, CD90, CD105, and lack of CD14, CD34, and CD45. However, according to transcriptome analyses, they differ significantly in their expression of more than 590 genes. Factors involved in bone metabolism, including alkaline phosphatase (P < 0.05), osteoglycin (P < 0.05), osteomodulin (P < 0.05), runt-related transcription factor 2 (Runx2) (P < 0.04), and WISP2 (P < 0.05), were expressed at significantly lower levels in pMSC, but twist-related protein 2 (Twist2) (P < 0.0002) was expressed at significantly higher levels. The osteogenic differentiation capacity of pMSC was very low. The adipogenic differentiation was somewhat more prominent in bmMSC, while the chondrogenic differentiation seemed not to differ between bmMSC and pMSC, as determined by histochemical staining. However, expression and induction of peroxisome proliferator-activated receptor gamma-2 (PPARg2) and Sox9, factors involved in early adipogenesis and chondrogenesis, respectively, were higher in bmMSC. We conclude that despite many similarities between bmMSC and pMSC, when expanded under identical conditions, they vary considerably with respect to their in vitro differentiation potential. For regenerative purposes, the choice of MSC may therefore influence the outcome of a treatment considerably.

Human Placenta-Derived CD146-Positive Mesenchymal Stromal Cells Display a Distinct Osteogenic Differentiation Potential

“…Here we confirm that expression of CD146 correlates with the osteogenic differentiation capacity not only in human bmMSC as shown previously [2,4], but also in MSC from human term placenta. This includes the MSC derived from both the maternal and fetal sections of the placenta and is also in line with our recent studies [23,24]. For bmMSC CD146 has been considered to be an indicator of "stemness" since it's expression correlated with the tri-lineage differentiation capacity of bmMSC clones [33].…”

“…We therefore extended our recent studies [23,24] and investigated if expression of CD146 on pMSC also correlated with a higher osteogenic potential. Here we report that the CD146 + pMSC generated osteoblasts in vitro upon osteogenic induction, whereas CD146 -pMSC failed to do so.…”

“…Mesenchymal stromal cells were isolated from normal, healthy human term placenta (from n>10 donors) as described recently [23,24]. The endometrial maternal part of the placenta was separated from the fetal part in order to enrich for maternal (pmMSC) and fetal (pfMSC) subsets of placenta MSC (pMSC This article has been peer-reviewed and accepted for publication, but has yet to undergo copyediting and proof correction.…”

“…The MSC were isolated from human term placenta as described recently [23,24] and characterized [3,5]. MSC from the maternal and fetal parts expressed CD73, CD90…”

“…The final published version may differ from this proof. transcription factor 2 (Runx2) significantly higher than pMSC and this correlated with a better osteogenic differentiation capacity of bmMSC [23,24]. CD146, also referred to as melanoma adhesion molecule (MCAM), cell surface glycoprotein MUC18, or Sendo1 antigen, is a cell adhesion molecule expressed on endothelial cells [25], B and T lymphocytes [26], smooth muscle cells [27,28], pericytes [29], and its expression has been described on MSC from different sources [4,7,[30][31][32][33][34].…”