Sphingosine 1-phosphate induces differentiation of adipose tissue-derived mesenchymal stem cells towards smooth muscle cells

Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid which regulates multiple biological parameters in a number of cell types, including stem cells. Here we report, for the first time, that S1P dose-dependently stimulates differentiation of adipose tissue-derived mesenchymal stem cells (ASMC) towards smooth muscle cells. Indeed, S1P not only induced the expression of smooth muscle cell-specific proteins such as α-smooth muscle actin (αSMA) and transgelin, but also profoundly affected ASMC morphology by enhancing cytoskeletal F-actin assembly, which incorporated αSMA. More importantly, S1P challenge was responsible for the functional appearance of Ca²⁺ currents, characteristic of differentiated excitable cells such as smooth muscle cells. By employing various agonists and antagonists to inhibit S1P receptor subtypes, S1P₂ turned out to be critical for the pro-differentiating effect of S1P, while S1P₃ appeared to play a secondary role. This study individuates an important role of S1P in AMSC which can be exploited to favour vascular regeneration. Received 06 March 2009; accepted 17 March 2009     

Macrophages derived from bone marrow modulate differentiation of myeloid dendritic cells

Dendritic cells (DC) are specialized antigen-presenting cells. Bone marrow monocytes have been widely used to generate murine myeloid DC. We found that mouse macrophages derived from bone marrow CD11b⁺ monocytes influenced the differentiation of these precursors into DC. Modulation of differentiation was demonstrated by the down-regulation of CD11c, CD40, and CD86 expression and by IL-12 production. DC differentiated in the presence of conditioned medium from bone marrow-derived macrophage culture (MCM) had impaired ability to stimulate proliferation of, and IFN- γ production by, allogeneic CD4⁺ T cells. This inhibition of DC differentiation was mainly mediated by secretory products from macrophages but not by cell-cell contact. MCM contained higher concentrations of macrophage-colony-stimulating factor (M-CSF), IL-10, and TGF- β1, whereas IL-6 remained unchanged compared with conditioned medium from fresh monocytes. M-CSF may be the major mediator in MCM inhibiting DC differentiation. This study demonstrates an important influence of bone marrow-derived macrophages on DC precursors during DC differentiation. Received 12 September 2006; received after revision 20 October 2006; accepted 13 November 2006     

Central nervous system stem cells in the embryo and adult

The central nervous system is generated from neural stem cells during embryonic development. These cells are multipotent and generate neurons, astrocytes and oligodendrocytes. The last few years it has been found that there are populations of stem cells also in the adult mammalian brain and spinal cord. In this paper, we review the recent development in the field of embryonic and adult neural stem cells. Received 26 March 1998; received after revision 27 April 1998; accepted 27 April 1998     

In vivo matrix-guided human mesenchymal stem cells

Microfracture of subchondral bone results in intrinsic repair of cartilage defects. Stem or progenitor cells from bone marrow have been proposed to be involved in this regenerative process. Here, we demonstrate for the first time that mesenchymal stem (MS) cells can in fact be recovered from matrix material saturated with cells from bone marrow after microfracture. This also introduces a new technique for MS cell isolation during arthroscopic treatment. MS cells were phenotyped using specific cell surface antibodies. Differentiation of the MS cells into the adipogenic, chondrogenic and osteogenic lineage could be demonstrated by cultivation of MS cells as a monolayer, as micromass bodies or mesenchymal microspheres. This study demonstrates that MS cells can be attracted to a cartilage defect by guidance of a collagenous matrix after perforating subchondral bone. Protocols for application of MS cells in restoration of cartilage tissue include an initial invasive biopsy to obtain the MS cells and time-wasting in vitro proliferation and possibly differentiation of the cells before implantation. The new technique already includes attraction of MS cells to sites of cartilage defects and therefore may overcome the necessity of in vitro proliferation and differentiation of MS cells prior to transplantation. Received 3 November 2005; received after revision 15 December 2005; accepted 4 January 2006     

Human stem cells as a model for cardiac differentiation and disease

Studies on identification, derivation and characterization of human stem cells in the last decade have led to high expectations in the field of regenerative medicine. Although it is clear that for successful stem cell-based therapy several obstacles have to be overcome, other opportunities lay ahead for the use of human stem cells. A more immediate application would be the development of human models for cell-type specific differentiation and disease in vitro. Cardiomyocytes can be generated from stem cells, which have been shown to follow similar molecular events of cardiac development in vivo. Furthermore, several monogenic cardiovascular diseases have been described, for which in vitro models in stem cells could be generated. Here, we will discuss the potential of human embryonic stem cells, cardiac stem cells and the recently described induced pluripotent stem cells as models for cardiac differentiation and disease. Received 07 August 2008; received after revision 26 September 2008; accepted 03 October 2008     

Insights into autotransplantation: the unexpected discovery of specific induction systems in bone marrow stromal cells

Many kinds of cells, including embryonic stem cells and tissue stem cells, have been considered candidates for transplantation therapy for neuro- and muscle-degenerative diseases. Bone marrow stromal cells (MSCs) also have great potential as therapeutic agents since they are easily isolated and can be expanded from patients without serious ethical or technical problems. Recently, new methods for the highly efficient and specific induction of functional neurons and skeletal muscle cells have been developed for MSCs. These induced cells were transplanted into animal models of stroke, Parkinson’s disease and muscle degeneration, resulting in the successful integration of transplanted cells and improvement in the behavior of the transplanted animals. Here I describe the discovery of these induction systems and focus on the potential use of MSC-derived cells for ‘auto-cell transplantation therapy’ in neuro- and muscle-degenerative diseases. Received 27 April 2006; received after revision 5 June 2006; accepted 22 August 2006     

小型猪骨髓间充质干细胞经心导管冠状动脉移植及其迁移和分化的研究

目的建立小型猪心导管介入冠状动脉治疗模型,为骨髓间充质于细胞（MSCs）移植治疗心血管疾病提供新的方法,观察骨髓间充质干细胞经心导管介入冠状动脉移植后在心肌内的迁移及分化。方法选用冠状动脉解剖生理特点与人类相似的小型猪,应用心导管介入技术将体外培养扩增的小型猪自体MSCs移植进入左冠状动脉前降支,用免疫荧光检测即刻移植和移植后6W移植细胞的肌钙蛋白T（cTnT）、缝隙连接蛋白43（Cx43）、anti－Ⅷfactor的表达。结果成功的完成了小型猪心导管介入冠状动脉进行自体骨髓间充质干细胞移植。移植细胞存活,向心肌组织迁移,并向心肌细胞和毛细血管方向分化。结论该方法稳定,技术先进。可进行准确的定位和动态观测,为临床应用提供了一个可靠的技术平台。MSCs移植后在心肌内发生迁移及分化。     

Analysis of OCT4 expression in an extended panel of human tumor cell lines from multiple entities and in human mesenchymal stem cells

OCT4 is considered a main regulator of embryonic stem cell pluripotency and self renewal capacity. It was shown that relevant OCT4 expression only occurs in cells of embryonic pluripotent nature. However, several recent publications claimed to have demonstrated OCT4 expression in human somatic tumor cells, human adult stem or progenitor cells and differentiated cells.We analysed 42 human tumor cell lines from 13 entities and human bone marrowderived mesenchymal stem cells (MSC). To validate OCT4 expression we used germ cell tumor (GCT) cell lines, derived xenografts and GCT samples. Analysis by RT-PCR, western blotting, immunocytochemistry and immunohistochemistry was performed. With exception of typical embryonal carcinoma cells, we did not observe reliable OCT4 expression in somatic tumor cell lines and MSC. We suggest that a high level of expression of the OCT4 protein together with its nuclear localization still remains a reliable and definitive feature of cells with embryonic pluripotent nature. Received 30 September 2008; received after revision 05 November 2008; accepted 10 November 2008     

Effects of pre- and post-irradiation glucan treatment on pluripotent stem cells,granulocyte, macrophage and erythroid progenitor cells,and hemopoietic stromal cells

Summary Glucan, a beta-1, 3 polyglucose, was administered to mice either 1 h before or 1 h after a 650 rad exposure to cobalt-60 radiation. Compared to radiation controls, glucan-treated mice consistantly exhibited a more rapid recovery of pluripotent stem cells and committed granulocyte, macrophage, and erythroid progenitor cells. This may partially explain the mechanism by which glucan also enhances survival in otherwise lethally irradiated mice.     

Generative models: Human embryonic stem cells and multiple modeling relations

Model organisms are at once scientific models and concrete living things. It is widely assumed by philosophers of science that (1) model organisms function much like other kinds of models, and (2) that insofar as their scientific role is distinctive, it is in virtue of representing a wide range of biological species and providing a basis for generalizations about those targets. This paper uses the case of human embryonic stem cells (hESC) to challenge both assumptions. I first argue that hESC can be considered model organisms, analogous to classic examples such as Escherichia coli and Drosophila melanogaster. I then discuss four contrasts between the epistemic role of hESC in practice, and the assumptions about model organisms noted above. These contrasts motivate an alternative view of model organisms as a network of systems related constructively and developmentally to one another. I conclude by relating this result to other accounts of model organisms in recent philosophy of science.     

Effect of halogenmethylenebisphosphonates on bone cells in culture and on bone resorption in vivo

Summary Dihalogenmethylenebisphosphonates increase alkaline phosphatase activity and fatty acid oxidation in calvaria cells in culture (Cl₂MBP>Br₂MBPF₂MBP). The monohalogen C1MBP and the non-halogenated analogues are less active on phosphatase and inactive on or inhibitory towards fatty acid oxidation. The three dihalogenbisphosphonates and C1MBP inhibit bone resorption in vivo, Cl₂MBP most strongly.Acknowledgments. We thank Miss M.-L. Aebersold, Miss J. Portenier, Mrs I. Tschudi and Mrs Ch. Marti for their skilled technical assistance. This work has been supported by the Swiss National Science Foundation (grant 3.937.82), by the Procter & Gamble Company, Cincinnati, USA, by the Istituto Gentili S.p.A., Pisa, Italy, and by the Ausbildungs- und Förderungsfonds der Arbeitsgemeinschaft für Osteosynthese (AO), Chur, Switzerland.     

Changes in intracellular pH and cell volume during the early phase of DMSO-induced differentiation of friend erythroleukemia cells

Summary Changes in intracellular pH and water volume were measured after treatment of Friend erythroleukemia cells with 1.5% DMSO. It was found that a continuous decrease in pH_i occurred, beginning 1 h after induction and a decline in pH_i of 0.18 was measured after 9 h. In addition a decline in cellular water volume, of 12% only 15 min after induction, and 23% after 9 h, was observed.11 December 1986Acknowlegments. This work was supported by the Deutsche Forschungsgemeinschaft.     

Stem cells and their niche: a matter of fate

Embryonic stem cells provide an in vitro model for developmental biologists to study cell fate decisions during ontogenesis, while somatic stem cells allow physiologists to understand tissue homeostasis in the adult. The behavior of stem cells is dependent on an intimate relationship with a supportive niche. This brief review highlights some of the most important recent trends in stem cell biology, focusing in particular on the supportive microenvironments for both embryonic and adult stem cells. Known intrinsic and extrinsic molecular players from the best-characterized stem cell types are summarized, illuminating a number of shared environmental cues among tissues originating from all three embryonic germ layers. Received 6 October 2005; received after revision 27 December 2005; accepted 17 January 2006     

CD20-related signaling pathway is differently activated in normal and dystrophic circulating CD133+ stem cells

Among the heterogeneous population of circulating hematopoietic and endothelial progenitors, we identified a subpopulation of CD133⁺ cells displaying myogenic properties. Unexpectedly, we observed the expression of the B-cell marker CD20 in blood-derived CD133⁺ stem cells. The CD20 antigen plays a role in the modulation of intracellular calcium homeostasis through signaling pathways activation. Several observations suggest that an increase in intracellular calcium concentration ([Ca²⁺]_i) could be involved in the etiology of the Duchenne muscular dystrophy (DMD). Here, we show that a CD20-related signaling pathway able to induce an increase in [Ca²⁺]_i is differently activated after brain derived neurotrophic factor (BDNF) stimulation of normal and dystrophic blood-derived CD133⁺ stem cells, supporting the assumption of a “CD20-related calcium impairment-affecting dystrophic cells. Presented findings represent the starting point toward the expansion of knowledge on pathways involved in the pathology of DMD and in the behavior of dystrophic blood-derived CD133⁺ stem cells. Received 15 October 2008; received after revision 27 November 2008; accepted 05 December 2008