Perivascular Human Endometrial Mesenchymal Stem Cells Express Pathways Relevant to Self-Renewal, Lineage Specification, and Functional Phenotype1

Abstract

Human endometrium regenerates on a cyclic basis from candidate stem/progenitors whose genetic programs are yet to be determined. A subpopulation of endometrial stromal cells, displaying key properties of mesenchymal stem cells (MSCs), has been characterized. The endometrial MSC (eMSC) is likely the precursor of the endometrial stromal fibroblast. The goal of this study was to determine the transcriptome and signaling pathways in the eMSC to understand its functional phenotype. Endometrial stromal cells from oocyte donors (n = 20) and patients undergoing benign gynecologic surgery (n = 7) were fluorescence-activated cell sorted into MCAM (CD146)(+)/PDGFRB(+) (eMSC), MCAM (CD146)(-)/PDGFRB(+) (fibroblast), and MCAM (CD146)(+)/PDGFRB(-) (endothelial) populations. The eMSC population contained clonogenic cells with a mesenchymal phenotype differentiating into adipocytes when cultured in adipogenic medium. Gene expression profiling using Affymetrix Human Gene 1.0 ST arrays revealed 762 and 1518 significantly differentially expressed genes in eMSCs vs. stromal fibroblasts and eMSCs vs. endothelial cells, respectively. By principal component and hierarchical clustering analyses, eMSCs clustered with fibroblasts and distinctly from endothelial cells. Endometrial MSCs expressed pericyte markers and were localized by immunofluorescence to the perivascular space of endometrial small vessels. Endometrial MSCs also expressed genes involved in angiogenesis/vasculogenesis, steroid hormone/hypoxia responses, inflammation, immunomodulation, cell communication, and proteolysis/inhibition, and exhibited increased Notch, TGFB, IGF, Hedgehog, and G-protein-coupled receptor signaling pathways, characteristic of adult tissue MSC self-renewal and multipotency. Overall, the data support the eMSC as a clonogenic, multipotent pericyte that displays pathways of self-renewal and lineage specification, the potential to respond to conditions during endometrial desquamation and regeneration, and a genetic program predictive of its differentiated lineage, the stromal fibroblast.

An α7 nicotinic receptor-G protein pathway complex regulates neurite growth in neural cells*

“…PNU, Nic, and Bgtx occupy a common binding site on the a7 receptor (Pankratov et al, 2002;Grabe et al, 2012b;Spitzer et al, 2012). As shown in Fig.…”

Endometrial inflammation and effect on implantation improvement and pregnancy outcome

“…Endothelial cells are localized in blood vessels suggesting their involvement in angiogenesis whereas the two other populations are located in the stroma. No stem cells were observed in the luminal surface (Spitzer et al 2012). Along this line, it was shown that re-epithelialization initiates around the remaining glandular stumps (Ludwig & Metzger 1976, Ludwig & Spornitz 1991.…”

“…However, these cells were shown to be stimulated in vivo when tissue is damaged (Ramalho-Santos et al 2002, Venezia et al 2004, suggesting that endometrial regeneration may be the result of the tissue breakdown caused during menses. It was shown that endometrial stem cells express genes that are involved in the response to inflammation (Spitzer et al 2012) and migrate toward extracellular matrix proteolytic digests, formed in the injured site (Crisan et al 2008). Based on these observations, we postulate that the injury-induced inflammatory reaction stimulate endometrial stem cell proliferation, migration, and differentiation that may be Figure 1 Suggested model for the favorable effect of injury-induced inflammation on implantation.…”

Adult Human Mesenchymal Stem Cell Differentiation at the Cell Population and Single-Cell Levels Under Alternating Electric Current

“…To date, the Fluidigm single-cell analysis method has been used with various stem cells types, such as, mouse hematopoietic stem cells, 19,20 mouse embryonic stem, 21 human cancer stem cells, 16 and human 22 and mouse 23 mesenchymal stem cells mostly in the presence of bioactive chemicals but not under a biophysical stimulus. Exposure of hMSCs to the optimal alternating electric current conditions examined in the present study provided evidence of homogeneous (defined as the uniform expression of a specific gene between 5 and 15; Fig.…”