Gene Expression of Extracellular Matrix Components in Human Amniotic Cells - A Pilot Study

Objectives: Identification of microenvironmental components, which significantly affect the fate of amniotic stem cells, is one of the essential conditions for their in vitro preparation for clinical applications. Control of their gene expression seems to be crucial for in vitro reconstitution of the natural amniotic microenvironment and modulation of the stem cell phenotype both, in vitro and in vivo. The aim of the study was to analyze multi-gene expressions for ECM components in human amnion cells (hACs) as compared to differentiated cells of a mesenchymal and ectodermal origin.Material and methods: hACs were isolated from normal human placentas at term. SSEA-4+ cells were visualized in vitro by immunofluorescence microscopy and counted by flow cytometry. The expressions of 84 genes were assayed by the RT-PCR Array method and analyzed by Web-based PCR Array Data Analysis Software. These expressions were compared among hACs, fibroblasts, and keratinocytes.Results: Almost 86% of the primarily cultured hACs exhibited expression of the SSEA-4 surface marker. In these cells, the expression of 7 genes for ECM structural components, 4 for adhesion proteins, 3 for integrin subunits, and 2 for metalloproteinases was strong: over 100-fold up-or down-regulated as compared to fibroblasts. These differences in gene expressions were less distinct when hAC were compared with keratinocytes.Conclusions: hACs exhibit highly different expression of several ECM-associated genes as compared to differentiated cells, especially of mesenchymal origin. The products of these genes, via an autoregulatory mechanism, might determine the nature of ECM-stem cell interactions, which are crucial for their stemness and potential differentiation abilities.