Stem Cell Biology Unit

Göttingen, Germany

Stem Cell Biology Unit

Göttingen, Germany
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Sagi B.,Stem Cell Biology Unit | Maraghechi P.,Agricultural Biotechnology Center | Urban V.S.,Stem Cell Biology Unit | Urban V.S.,Semmelweis University | And 8 more authors.
Stem Cells and Development | Year: 2012

Although mesenchymal stem cells (MSCs) of distinct tissue origin have a large number of similarities and differences, it has not been determined so far whether tissue-resident MSCs are the progenies of one ancestor cell lineage or the results of parallel cell developmental events. Here we compared the expression levels of 177 genes in murine MSCs derived from adult and juvenile bone marrow and adult adipose tissue, as well as juvenile spleen, thymus, and aorta wall by quantitative real-time polymerase chain reaction and the results were partially validated at protein level. All MSC lines uniformly expressed a large set of genes including well-known mesenchymal markers, such as α-smooth muscle actin, collagen type I α-chain, GATA6, Mohawk, and vimentin. In contrast, pluripotency genes and the early mesodermal marker T-gene were not expressed. On the other hand, different MSC lines consistently expressed distinct patterns of Hox genes determining the positional identity of a given cell population. Moreover, MSCs of different origin expressed a few other transcription factors also reflecting their topological identity and so the body segment or organ to which they normally contributed in vivo: (1) thymus-derived cells specifically expressed Tbx5 and Pitx2; (2) spleen-derived MSCs were characterized with Tlx1 and Nkx2.5; (3) Pitx1 designated femoral bone marrow cells and (4) En2 appeared in aorta wall-derived MSCs. Thus, MSCs exhibited topographic identity and memory even after long-term cultivation in vitro. On the basis of these results, we suggest that postnatal MSCs isolated from different anatomical sites descend from precursor cells developing in the postsegmentation mesoderm. © 2012 Mary Ann Liebert, Inc.

Roos C.,German Primate Center | Zinner D.,German Primate Center | Kubatko L.S.,Ohio State University | Schwarz C.,German Primate Center | And 13 more authors.
BMC Evolutionary Biology | Year: 2011

Background: Colobine monkeys constitute a diverse group of primates with major radiations in Africa and Asia. However, phylogenetic relationships among genera are under debate, and recent molecular studies with incomplete taxon-sampling revealed discordant gene trees. To solve the evolutionary history of colobine genera and to determine causes for possible gene tree incongruences, we combined presence/absence analysis of mobile elements with autosomal, X chromosomal, Y chromosomal and mitochondrial sequence data from all recognized colobine genera. Results: Gene tree topologies and divergence age estimates derived from different markers were similar, but differed in placing Piliocolobus/Procolobus and langur genera among colobines. Although insufficient data, homoplasy and incomplete lineage sorting might all have contributed to the discordance among gene trees, hybridization is favored as the main cause of the observed discordance. We propose that African colobines are paraphyletic, but might later have experienced female introgression from Piliocolobus/ Procolobus into Colobus. In the late Miocene, colobines invaded Eurasia and diversified into several lineages. Among Asian colobines, Semnopithecus diverged first, indicating langur paraphyly. However, unidirectional gene flow from Semnopithecus into Trachypithecus via male introgression followed by nuclear swamping might have occurred until the earliest Pleistocene. Conclusions: Overall, our study provides the most comprehensive view on colobine evolution to date and emphasizes that analyses of various molecular markers, such as mobile elements and sequence data from multiple loci, are crucial to better understand evolutionary relationships and to trace hybridization events. Our results also suggest that sex-specific dispersal patterns, promoted by a respective social organization of the species involved, can result in different hybridization scenarios. © 2011 Roos et al; licensee BioMed Central Ltd.

Aeckerle N.,Stem Cell Biology Unit | Dressel R.,University of Gottingen | Behr R.,Stem Cell Biology Unit
Cells Tissues Organs | Year: 2013

Single-cell suspensions derived from immature rodent and ungulate testes can reconstitute testicular cords upon grafting into immunodeficient mice. In the present study, neonatal common marmoset monkey (Callithrix jacchus) testes were digested to a single-cell suspension, which was transplanted subcutaneously into immunodeficient mice. After 9 or 18 weeks of incubation, the derivatives of the grafted single-cell suspensions were retrieved and analyzed histologically and immunohistochemically. Three of 4 (75%) neonatal grafts exhibited reconstituted seminiferous cords strongly resembling seminiferous cords of the intact neonatal testis. The cords consisted of Sertoli cells, germ cells and peritubular myoid cells, which was confirmed by immunohistochemical marker analysis. Three-dimensional reconstruction models of the grafts revealed elongated tubules. Some of the tubules were branched, which occurs also in vivo, as we show here for the marmoset monkey. Importantly, no teratoma formation by immature pluripotency factor-expressing germ cells was observed. In summary, the reconstituted testicular cords were almost indistinguishable from the cords formed in situ, thereby impressively demonstrating a very high reconstructive potential of a single-cell suspension obtained from the neonatal marmoset monkey testis. To our knowledge, this is the first study demonstrating testicular cord neomorphogenesis for a primate species ex situ. © 2013 S. Karger AG, Basel.

Hegyi B.,Stem Cell Biology Unit | Kudlik G.,Stem Cell Biology Unit | Monostori E.,Hungarian Academy of Sciences | Uher F.,Stem Cell Biology Unit
Biochemical and Biophysical Research Communications | Year: 2012

In recent years it has become clear that mesenchymal stem or stromal cells (MSCs) are capable of modulating inflammatory and immune responses through interaction with a wide variety of cells. Whereas several studies indicated that PGE2 is one of the chief soluble mediators involved in these processes, here we investigated prostaglandin E2 (PGE2) production of murine bone marrow- (BM-) and adipose tissue- (Ad-) derived MSCs stimulated with pro-inflammatory cytokines TNF-α and IFN-γ, or co-cultured with ConA-induced T-cell blasts. We found that both MSC populations are able to produce high amounts of PGE2 in MSC/activated T-cell co-cultures. This effect was markedly attenuated when direct cell-cell contact was prevented in transwell system, indicating that the elicitation of the PGE2 secretion of MSCs is contact-dependent in this experimental setting. In contrast, when soluble recombinant pro-inflammatory cytokines were added to the MSC cultures, TNF-α and IFN-γ act synergistically to induce PGE2 production, whereas only high amount of TNF-α but not IFN-γ was able to do so alone. Although the PGE2 secretion by MSCs was completely abrogated by addition of indomethacin under all culture conditions tested, L-NMA, a NOS inhibitor could only partially inhibit it when the cells were elicited in the concomitant presence of TNF-α and IFN-γ. These results, combined with others, suggest that NO acts downstream of IFN-γ but upstream of COX2. Taken together, our findings demonstrate that the induction of PGE2 secretion by BM- and Ad-MSCs is not mediated by a single or unique, nonredundant molecular mechanism under different experimental conditions. © 2012 Elsevier Inc.

PubMed | Stem Cell Biology Unit and Hungarian Academy of Sciences
Type: Journal Article | Journal: Experimental cell research | Year: 2016

Mesenchymal stem or stromal cells (MSCs) act on different components of the immune response including macrophages (Ms). Therefore this study has been committed to explore how MSCs may modify the effect of M polarization upon an inductive environment using mouse bone marrow (BM)-derived nave, unpolarized Ms. Phagocytosis of various M subtypes was different since M1 and M2b showed poorer, while M2a higher rate of phagocytosis. MSCs significantly promoted yeast ingestion by M1 and M2b and diminished it by M2a cells. Under polarizing conditions, MSCs profoundly affected the TNF production of M subtypes since M1 and M2b Ms produced less and M2a produced higher amount of TNF while the amount of IL-10 was not affected. The most striking effect of MSCs was registered on M2b cells since the inflammatory TNF dominance remarkably shifted to the immunosuppressive IL-10. Prepolarized M1 cells readily converted to M2a and M2b states when polarizing conditions changed from M1 to M2a or M2b induction, respectively. Repolarizing from M1 to M2a resulted in the decline of IL-10 and TNF and defined elevation of Ym1 similar to levels characteristic to M2a primarily polarized from nave BM-Ms. Similarly, polarization of M1 to M2b Ms was successful showing increase in IL-10 and reduction in TNF levels characteristic to M2b cells. However, when co-culturing with MSCs, M1-M2a or M1-M2b transition was not affected. Crosstalk between Ms and MSCs depended on PGE-2 since COX-2 inhibition reduced the effect of MSCs to establish an IL-10-dominant cytokine production by Ms.

Hegyi B.,Institute of Molecular Pharmacology | Kornyei Z.,Institute of Experimental Medicine | Ferenczi S.,Institute of Experimental Medicine | Fekete R.,Institute of Experimental Medicine | And 5 more authors.
Stem Cells and Development | Year: 2014

Mesenchymal stems or stromal cells (MSCs) are rare multipotent cells with potent regenerative and immunomodulatory properties. Microglial cells (MGs) are specialized tissue macrophages of the central nervous system (CNS) that continuously survey their environment with highly motile extensions. Recently, several studies have shown that MSCs are capable of reprogramming microglia into an "M2-like" phenotype characterized by increased phagocytic activity and upregulated expression of anti-inflammatory mediators in vitro. However, the precise polarization states of microglia in the presence of MSCs under physiological or under inflammatory conditions remain largely unknown. In this study, we found that MSCs induce a mixed microglia phenotype defined as Arg1-high, CD86-high, CD206-high, IL-10-high, PGE2-high, MCP-1/CCL2-high, IL-1β-moderate, NALP-3-low, and TNF-α-low cells. These MSC-elicited MGs have high phagocytic activity and antigen-presenting ability. Lipopolysaccharide is able to shape this microglia phenotype quantitatively, but not qualitatively in the presence of MSCs. This unique polarization state resembles a novel regulatory microglia phenotype, which might contribute to the resolution of inflammation and to tissue repair in the CNS. © Mary Ann Liebert, Inc. 2014.

Agnarsson B.,University of Iceland | Halldorsson J.,University of Iceland | Arnfinnsdottir N.,University of Iceland | Ingthorsson S.,Stem Cell Biology Unit | And 2 more authors.
Microelectronic Engineering | Year: 2010

We present a detailed account of processing issues related to fabrication of optical waveguide sensors intended for evanescent-wave sensing in aqueous solutions or surface-bound fluorescence excitation in biological samples. The waveguides consist of a polymer layer on top of a fluoropolymer (Cytop™) cladding. The fluoropolymer is closely index-matched to water, providing a symmetric cladding environment which simplifies optical excitation and provides tunability in penetration depth not available with other evanescent-wave techniques. We present methods of controlling the wettability of the fluoropolymer surface and improving adhesion to the core waveguide layer. Furthermore, we demonstrate the application of the waveguide structure to fluorescence imaging of cultured cells. © 2009 Elsevier B.V. All rights reserved.

Langenstroth D.,Institute of Reproduction and Regenerative Biology | Kossack N.,Institute of Reproduction and Regenerative Biology | Westernstroer B.,Institute of Reproduction and Regenerative Biology | Wistuba J.,Institute of Reproduction and Regenerative Biology | And 3 more authors.
Human Reproduction | Year: 2014

STUDY QUESTION Can primate spermatogonial cultures be optimized by application of separation steps and well defined culture conditions? SUMMARY ANSWER We identified the cell fraction which provides the best source for primate spermatogonia when prolonged culture is desired. WHAT IS KNOWN ALREADY Man and marmoset show similar characteristics in regard to germ cell development and function. Several protocols for isolation and culture of human testis-derived germline stem cells have been described. Subsequent analysis revealed doubts on the germline origin of these cells and characterized them as mesenchymal stem cells or fibroblasts. Studies using marmosets as preclinical model confirmed that the published isolation protocols did not lead to propagation of germline cells. STUDY DESIGN, SIZE, DURATION Testicular cells derived from nine adult marmoset monkeys (Callithrix jacchus) were cultured for 1, 3, 6 and 11 days and consecutively analyzed for the presence of spermatogonia, differentiating germ cells and testicular somatic cells. PARTICIPANTS/MATERIALS, SETTING, METHODS Testicular tissue of nine adult marmoset monkeys was enzymatically dissociated and subjected to two different cell culture approaches. In the first approach all cells were kept in the same dish (non-separate culture, n = 5). In the second approach the supernatant cells were transferred into a new dish 24 h after seeding and subsequently supernatant and attached cells were cultured separately (separate culture, n = 4). Real-time quantitative PCR and immunofluorescence were used to analyze the expression of reliable germ cell and somatic markers throughout the culture period. Germ cell transplantation assays and subsequent wholemount analyses were performed to functionally evaluate the colonization of spermatogonial cells. MAIN RESULTS AND THE ROLE OF CHANCE This is the first report revealing an efficient isolation and culture of putative marmoset spermatogonial stem cells with colonization ability. Our results indicate that a separation of spermatogonia from testicular somatic cells is a crucial step during cell preparation. We identified the overgrowth of more rapidly expanding somatic cells to be a major problem when establishing spermatogonial cultures. Initiating germ cell cultures from the supernatant and maintaining germ cells in suspension cultures minimized the somatic cell contamination and provided enriched germ cell fractions which displayed after 11 days of culture a significantly higher expression of germ cell markers genes (DDX-4, MAGE A-4; P < 0.05) compared with separately cultured attached cells. Additionally, germ cell transplantation experiments demonstrated a significantly higher absolute number of cells with colonization ability (P < 0.001) in supernatant cells after 11 days of separate culture. LIMITATIONS, REASONS FOR CAUTION This study presents a relevant aspect for the successful setup of spermatogonial cultures but provides limited data regarding the question of whether the long-term maintenance of spermatogonia can be achieved. Transfer of these preclinical data to man may require modifications of the protocol. WIDER IMPLICATIONS OF THE FINDINGS Spermatogonial cultures from rodents have become important and innovative tools for basic and applied research in reproductive biology and veterinary medicine. It is expected that spermatogonia-based strategies will be transformed into clinical applications for the treatment of male infertility. Our data in the marmoset monkey may be highly relevant to establish spermatogonial cultures of human testes. STUDY FUNDING/COMPETING INTEREST(S) Funding was provided by the DFG-Research Unit FOR 1041 Germ Cell Potential (SCHL394/11-2) and by the Graduate Program Cell Dynamics and Disease (CEDAD) together with the International Max Planck Research School - Molecular Biomedicine (IMPRS-MBM). The authors declare that there is no conflict of interest. TRIAL REGISTRATION NUMBER Not applicable. © 2014 The Author.

Albert S.,University of Munster | Wistuba J.,University of Munster | Eildermann K.,Stem Cell Biology Unit | Ehmcke J.,University of Munster | And 3 more authors.
Cells Tissues Organs | Year: 2012

The marmoset monkey is a valuable model in reproductive medicine. While previous studies have evaluated germ cell dynamics in the postnatal marmoset, the features of testicular somatic cells remain largely unknown. Therefore, the aim of this study was to establish marmoset-specific markers for Sertoli and peritubular cells (PTCs) and to compare protocols for the enrichment and culture of testicular cell types. Immunohistochemistry of Sertoli and PTC-specific markers - anti-müllerian hormone (AMH), vimentin (VIM), α-smooth muscle actin (SMA) - was performed and corresponding RNA expression profiles were established by quantitative PCR analysis (SOX9,AMH, FSHR,VIM, and SMA). For these analyses, testicular tissue from newborn (n = 4), 8-week-old (n = 4) and adult (n = 3) marmoset monkeys was used. Protocols for the enrichment and culture of testicular cell fractions from the 8-week-old marmoset monkeys (n = 3) were evaluated and cells were analyzed using germ cell- and somatic cell-specific markers. The expression of AMH, VIM and SMA reflects the proportion and differentiation status of Sertoli and PTCs at the RNA and the protein levels. While applied protocols did not support the propagation of germ cells in vitro, our analyses revealed that PTCs maintain their proliferative potential and constitute the dominant cell type after short- and long-term culture. Expression of functionally meaningful testicular somatic markers is similar in the human and the marmoset monkey, indicating that this primate can indeed be used as model for human testicular development. The PTC culture system established in this study will facilitate the identification of factors influencing male sex differentiation and spermatogenesis. Copyright © 2012 S. Karger AG, Basel.

Albert S.,University of Munster | Ehmcke J.,University of Munster | Wistuba J.,University of Munster | Eildermann K.,Stem Cell Biology Unit | And 3 more authors.
Reproduction | Year: 2010

The seminiferous epithelium in the nonhuman primate Callithrix jacchus is similarly organized to man. This monkey has therefore been used as a preclinical model for spermatogenesis and testicular stem cell physiology. However, little is known about the developmental dynamics of germ cells in the postnatal primate testis. In this study, we analyzed testes of newborn, 8-week-old, and adult marmosets employing immunohistochemistry using pluripotent stem cell and germ cell markers DDX4 (VASA), POU5F1 (OCT3/4), and TFAP2C (AP-2γ). Stereological and morphometric techniques were applied for quantitative analysis of germ cell populations and testicular histological changes. Quantitative RT-PCR (qRT-PCR) of testicular mRNA was applied using 16 marker genes establishing the corresponding profiles during postnatal testicular development. Testis size increased during the first 8 weeks of life with the main driver being longitudinal outgrowth of seminiferous cords. The number of DDX4-positive cells per testis doubled between birth and 8 weeks of age whereas TFAP2C- and POU5F1-positive cells remained unchanged. This increase in DDX4-expressing cells indicates dynamic growth of the differentiated A-spermatogonial population. The presence of cells expressing POU5F1 and TFAP2C after 8 weeks reveals the persistence of less differentiated germ cells. The mRNA and protein profiles determined by qRT-PCR and western blot in newborn, 8-week-old, and adult marmosets corroborated the immunohistochemical findings. In conclusion, we demonstrated the presence of distinct spermatogonial subpopulations in the primate testis exhibiting different dynamics during early testicular development. Our study demonstrates the suitability of the marmoset testis as a model for human testicular development. © 2010 Society for Reproduction and Fertility.

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