Amniotic fluid-derived cells: genome-wide expression in early and late cultures

Amniotic fluid stem cells (AFSCs) are of interest in regenerative medicine as a non-controversial and potentially 'abundant' source of stem cells. Progress has been made in understanding amniotic fluid stem cell biology, and amniotic fluid-derived cells have been induced to form neurons, osteoblasts, muscle cells, and others. Our study evaluates change in the genome-wide expression profile of amniotic fluid stem cells during in-vitro culture, using Affymetrix U133 Plus 2.0 microarray chips. We found that only 3.08% of gene probes were differentially expressed from early to late passage of AFSC culture. The differentially expressed genes were related to biological processes or cellular function - including transcription factors, protein kinases, and cytokines/growth factors. Other gene-sets of interest were oncogenes and tumor suppressor genes, which were a very small number of genes. We further analyzed the gene sets of interest using NIH DAVID and GSEA bioinformatics databases for gene annotations analysis. Applying false discovery rate correction, there was no significant difference in the genome-wide expression profiling between early and late passage. AFSCs maintain their genome-wide expression profile during in-vitro culture. Amniotic fluid-derived c-kit-positive cells were maintained in stem cell culture and genome-wide expression changes were studied and compared between early passage and late passage in culture.