Research Article Expression of Genes Related to Germ Cell Lineage and Pluripotency in Single Cells and Colonies of Human Adult Germ Stem Cells Sabine Conrad, 1 Hossein Azizi, 2,3,4 Maryam Hatami, 2 Mikael Kubista, 5,6 Michael Bonin, 7 Jörg Hennenlotter, 8 Karl-Dietrich Sievert, 8 and Thomas Skutella 2 1 Sabine Conrad, P.O. Box 12 43, 72072 T¨ ubingen, Germany 2 Institute for Anatomy and Cell Biology, Medical Faculty, University of Heidelberg, Im Neuenheimer Feld 307, 69120 Heidelberg, Germany 3 Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, P.O. Box 19395, Tehran 4644, Iran 4 Faculty of Biotechnology, Amol University of Special Modern Technologies, P.O. Box 46168, Amol 49767, Iran 5 TATAA Biocenter AB, Odinsgatan 28, 41103 G¨ oteborg, Sweden 6 Institute of Biotechnology at the Czech Academy of Sciences Videnska 1083, 14220 Prague 4, Czech Republic 7 Institute of Anthropology and Human Genetics, Microarray Facility, University Clinic, Calwerstraße 7, 72076 T¨ ubingen, Germany 8 Department of Urology, University of T¨ ubingen Hospital, Hoppe-Seyler-Straße 3, 72076 T¨ ubingen, Germany Correspondence should be addressed to Tomas Skutella; skutella@ana.uni-heidelberg.de Received 3 December 2014; Revised 9 February 2015; Accepted 11 February 2015 Academic Editor: Irma Virant-Klun Copyright © 2016 Sabine Conrad et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te aim of this study was to elucidate the molecular status of single human adult germ stem cells (haGSCs) and haGSC colonies, which spontaneously developed from the CD49f MACS and matrix- (collagen−/laminin+ binding-) selected fraction of enriched spermatogonia. Single-cell transcriptional profling by Fluidigm BioMark system of a long-term cultured haGSCs cluster in comparison to human embryonic stem cells (hESCs) and human fbroblasts (hFibs) revealed that haGSCs showed a characteristic germ- and pluripotency-associated gene expression profle with some similarities to hESCs and with a signifcant distinction from somatic hFibs. Genome-wide comparisons with microarray analysis confrmed that diferent haGSC colonies exhibited gene expression heterogeneity with more or less pluripotency. Te results of this study confrm that haGSCs are adult stem cells with a specifc molecular gene expression profle in vitro, related but not identical to true pluripotent stem cells. Under ES-cell conditions haGSC colonies could be selected and maintained in a partial pluripotent state at the molecular level, which may be related to their cell plasticity and potential to diferentiate into cells of all germ layers. 1. Background Human adult germ stem cells (haGSCs) derived from highly enriched spermatogonia isolated from adult human testicular tissue were shown to be highly versatile and having some sim- ilarities with human embryonic stem cells (hESCs), including the expression of genes associated with pluripotent cells and the ability to be in vitro diferentiated into a number of cell lineages comprising the three germ layers [1–6]. In the studies of Mizrak et al. [5], Chikhovskaya et al. [7], and Gonzalez et al. [8], the cells expressing markers of pluripotency were probably derived from mesenchymal stem cells (MSCs) or were more MSC-like. Moreover, it has also been proposed that haGSCs may be low-diferentiated testicular fbroblasts [9]. In contrast, Stimpfel et al. [10] demonstrated that both germ- and mesenchyme-derived stem cells were present in stem cell clusters from human testis biopsy, which could diferentiate into cells of all three germ Hindawi Publishing Corporation Stem Cells International Volume 2016, Article ID 8582526, 17 pages http://dx.doi.org/10.1155/2016/8582526