http://stemcellres.com The latest research articles published by Stem Cell Research & Therapy 2010-07-26T00:00:00Z This is an RSS newsfeed from BioMed Central It is intended to be used with an RSS reader. For more information about RSS newsfeeds from BioMed Central, visit http://www.biomedcentral.com/info/about/rss/ IntroductionGenetic manipulation of human embryonic stem cells (hESC) has been limited by their general resistance to common methods used to introduce exogenous DNA or RNA. Efficient and high throughput transfection of nucleic acids into hESC would be a valuable experimental tool to manipulate these cells for research and clinical applications. Methods: We investigated the ability of two commercially available electroporation systems, the Nucleofection(R) 96-well Shuttle(R) System from Lonza and the NeonTM Transfection System from Invitrogen to efficiently transfect hESC. Transfection efficiency was measured by FACS analysis for GFP and the viability of the transfected cells was determined by an ATP catalyzed luciferase reaction. The transfected cells were also analyzed by FACS for common markers of pluripotency. Results: Both systems are capable of transfecting hESC at high efficiencies with little loss of cell viability. However, the reproducibility and the ease of scaling for high throughput applications led us to perform more comprehensive tests on the Nucleofection(R) 96-well Shuttle(R) System. We demonstrate that this method yields a large fraction of transiently transfected cells with minimal loss of cell viability and pluripotency, producing protein expression from plasmid vectors in several different hESC lines. The method scales to a 96-well plate with similar transfection efficiencies at the start and end of the plate. We also investigated the efficiency with which stable transfectants can be generated and recovered under antibiotic selection. Finally, we found that this method is effective in the delivery of short synthetic RNA oligonucleotides (siRNA) into hESC for knockdown of translation activity via RNA interference. Conclusions: Our results indicate that these electroporation methods provide a reliable, efficient, and high-throughput approach to the genetic manipulation of hESC. http://stemcellres.com/content/1/4/23 Jennifer Moore Kristin Atze Percy Yeung Alana Toro-Ramos Cynthia Camarillo Kevin Thompson Christopher Ricupero Mark Brenneman Rick Cohen Ronald Hart Stem Cell Research & Therapy 2010, 1:23 2010-07-26T00:00:00Z doi:10.1186/scrt23 Stem Cell Research & Therapy 1757-6512 1 23 2010-07-26T00:00:00Z PDF Quyn and colleagues report that gut stem cells have a biased spindle orientation and asymmetric retention of label-retaining DNA. These features are lost in mouse and human tissues when the microtubule binding protein Apc is mutated. In the developing kidney, Apc acts downstream from primary cilium signaling to influence spindle orientation when noncanonical Wnt signaling predominates. Do gut stem cells also have primary cilia? http://stemcellres.com/content/1/3/21 Peter Satir Stem Cell Research & Therapy 2010, 1:21 2010-07-23T00:00:00Z doi:10.1186/scrt21 Stem Cell Research & Therapy 1757-6512 1 21 2010-07-23T00:00:00Z XML IntroductionOn the basis of the recently recognized potential of hematopoietic stem cells (HSCs) to give rise to hepatocytes, we here assessed the potential of granulocyte colony-stimulating factor (G-CSF)-mobilized bone marrow-derived CD34+ HSCs to contribute to faster recovery and promote regeneration process after acute liver injury by radiation. Methods: G-CSF-mobilized CD34+ HSCs (1 x105 cells per mouse) were injected via tail vein in the irradiated femal nonobese diabetic/severe combined immunodeficient mice. Irradiated control animals received only saline infusion. Results: The mobilized CD34+ HSCs significantly ameliorated radiation-induced liver damage. In the liver of recipient mice killed 21 days after irradiation, human albumin+ Y-chromosome+ hepatocyte-like cells, or human cytokeratin+Y-chromosome+ hepatocyte-like cells formed cords of hepatocytes, occupied about 30% of the 4-um section surrounding portal tracts. Furthermore, human-specific albumin mRNA expressed in the liver and human albumin was detected in the serum only in the CD34+ HSCs-treated mice. Conclusions: Treatment with G-CSF-mobilized CD34+ HSCs from bone marrow into peripheral blood could significantly promote tissue reparation after acute liver injury by radiation in mice, possibly by the ability of CD34+ HSCs to generate hepatocytes. So mobilization of CD34+ HSCs might offer a novel therapeutic approach for the treatment of radiation-induced complications after radiotherapy or other acute liver diseases in humans. http://stemcellres.com/content/1/3/22 Ning Li Li Zhang Huixiang Li Baijun Fang Stem Cell Research & Therapy 2010, 1:22 2010-07-15T00:00:00Z doi:10.1186/scrt22 Stem Cell Research & Therapy 1757-6512 1 22 2010-07-15T00:00:00Z PDF IntroductionAmniotic fluid harbors cells indicative of all three germ layers and pluripotent fetal amniotic fluid stem cells (AFS) are considered as potentially valuable for applications in cellular therapy and tissue engineering. We investigated if it is possible to direct the cell fate of AFS in vivo by transplantation experiments into a particular microenvironment, the mammary fat pad. This microenvironment provides the prerequisites to study stem cell function and the communication between mesenchymal and epithelial cells. Upon clearance of the endogenous epithelium, the ductal tree can be reconstituted by the transfer of exogenously provided mammary stem cells. Analogously, exogenously provided stem cells from other tissues can be investigated for their potential to contribute to mammary gland regeneration. Methods: We derived pluripotent murine AFS, measured the expression of stem cell markers and confirmed their in vitro differentiation potential. AFS were transplanted into cleared and non cleared fat pads of immunocompromised mice to evaluate their ability to assume particular cell fates under the instructive conditions of the fat pad microenvironment and the hormonal stimulation during pregnancy. Results: Transplantation of AFS into cleared fat pads alone or in the presence of exogenous mammary epithelial cells caused their differentiation into stroma and adipocytes and replaced endogenous mesenchymal components surrounding the ducts in co-transplantation experiments. Similarly, transplantation of AFS into fat pads which had not been previously cleared, led to AFS derived stromal cells surrounding the elongating endogenous ducts. AFS expressed the marker protein -SMA, but did not integrate into the myoepithelial cell layer of the ducts in virgin mice. Upon pregnancy a small number of AFS derived cells were present in acinar structures. Conclusions: Our data demonstrate that the microenvironmental cues of the mammary fat pad cause AFS to participate in mammary gland regeneration by providing mesenchymal components to emerging glandular structures, but do not incorporate or differentiate into ductal epithelial cells. http://stemcellres.com/content/1/3/20 Petra Klemmt Vida Vafaizadeh Bernd Groner Stem Cell Research & Therapy 2010, 1:20 2010-07-07T00:00:00Z doi:10.1186/scrt20 Stem Cell Research & Therapy 1757-6512 1 20 2010-07-07T00:00:00Z PDF Adipose tissue is now recognized as an accessible, abundant, and reliable site for the isolation of adult stem cells suitable for tissue engineering and regenerative medicine applications. The past decade has witnessed an explosion of preclinical data relating to the isolation, characterization, cryopreservation, differentiation, and transplantation of freshly isolated stromal vascular fraction cells and adherent, culture-expanded, adipose-derived stromal/stem cells in vitro and in animal models. This body of work has provided evidence supporting clinical translational applications of adipose-derived cells in safety and efficacy trials. The present article reviews the case reports and phase I-III clinical evidence using autologous adipose-derived cells that have been published, to date, in the fields of gastroenterology, neurology, orthopedics, reconstructive surgery, and related clinical disciplines. Future directions and challenges facing the field are discussed and evaluated. http://stemcellres.com/content/1/2/19 Jeffrey Gimble Farshid Guilak Bruce Bunnell Stem Cell Research & Therapy 2010, 1:19 2010-06-29T00:00:00Z doi:10.1186/scrt19 Stem Cell Research & Therapy 1757-6512 1 19 2010-06-29T00:00:00Z XML IntroductionMesenchymal stem cells (MSCs) offer promise for intervertebral disc (IVD) repair and regeneration because they are easily isolated and expanded, and can differentiate into several mesenchymal tissues. Notochordal (NC) cells contribute to IVD development, incorporate into the nucleus pulposus (NP), and stimulate mature disc cells. However, there have been no studies investigating the effects of NC cells on adult stem cell differentiation. The premise of this study is that IVD regeneration is more similar to IVD development than to IVD maintenance, and we hypothesize that soluble factors from NC cells differentiate MSCs to a phenotype characteristic of nucleus pulposus (NP) cells during development. The eventual clinical goal would be to isolate or chemically/recombinantly produce the active agent to induce the therapeutic effects, and to use it as either an injectable therapy for early intervention on disc disease, or in developing appropriately pre-differentiated MSC cells in a tissue engineered NP construct. Methods: Human MSCs from bone marrow were expanded and pelleted to form high-density cultures. MSC pellets were exposed to either control medium (CM), chondrogenic medium (CM with dexamethasone and transforming growth factor, (TGF)-β3) or notochordal cell conditioned medium (NCCM). NCCM was prepared from NC cells maintained in serum free medium for four days. After seven days culture, MSC pellets were analyzed for appearance, biochemical composition (glycosaminoglycans and DNA), and gene expression profile (sox-9, collagen types-II and III, laminin-β1 and TIMP1(tissue inhibitor of metalloproteinases-1)). Results: Significantly higher glycosaminoglycan accumulation was seen in NCCM treated pellets than in CM or TGFβ groups. With NCCM treatment, increased gene expression of collagen III, and a trend of increasing expression of laminin-β1 and decreased expression of sox-9 and collagen II relative to the TGFβ group was observed. Conclusions: Together, results suggest NCCM stimulates mesenchymal stem cell differentiation toward a potentially NP-like phenotype with some characteristics of the developing IVD. http://stemcellres.com/content/1/2/18 Casey Korecki Juan Taboas Rocky Tuan James Iatridis Stem Cell Research & Therapy 2010, 1:18 2010-06-16T00:00:00Z doi:10.1186/scrt18 Stem Cell Research & Therapy 1757-6512 1 18 2010-06-16T00:00:00Z XML IntroductionThis study aimed to determine the homing potential and fate of epidermal neural crest stem cells (eNCSCs) derived from hair follicles, and bone marrow-derived stem cells (BMSCs) of mesenchymal origin, in a lipopolysaccharide (LPS)-induced inflammatory lesion model in the rat brain. Both eNCSCs and BMSCs are easily accessible from adult tissues by using minimally invasive procedures and can differentiate into a variety of neuroglial lineages. Thus, these cells have the potential to be used in autologous cell-replacement therapies, minimizing immune rejection, and engineered to secrete a variety of molecules. Methods: Both eNCSCs and BMSCs were prelabeled with iron-oxide nanoparticles (IO-TAT-FITC) and implanted either onto the corpus callosum in healthy or LPS-lesioned animals or intravenously into lesioned animals. Both cell types were tracked longitudinally in vivo by using magnetic resonance imaging (MRI) for up to 30 days and confirmed by postmortem immunohistochemistry. Results: Transplanted cells in nonlesioned animals remained localized along the corpus callosum. Cells implanted distally from an LPS lesion (either intracerebrally or intravenously) migrated only toward the lesion, as seen by the localized MRI signal void. Fluorescence microscopy of the FITC tag on the nanoparticles confirmed the in vivo MRI data, Conclusions: This study demonstrated that both cell types can be tracked in vivo by using noninvasive MRI and have pathotropic properties toward an inflammatory lesion in the brain. As these cells differentiate into the glial phenotype and are derived from adult tissues, they offer a viable alternative autologous stem cell source and gene-targeting potential for neurodegenerative and demyelinating pathologies. http://stemcellres.com/content/1/2/17 Johanna Jackson Jon Golding Catherine Chapon William Jones Kishore Bhakoo Stem Cell Research & Therapy 2010, 1:17 2010-06-15T00:00:00Z doi:10.1186/scrt17 Stem Cell Research & Therapy 1757-6512 1 17 2010-06-15T00:00:00Z XML Based on their capacity to suppress immune responses, multipotent mesenchymal stromal cells (MSCs) are intensively studied for regenerative medicine. Moreover, MSCs have paracrine effects, including immunomodulation that occurs through the secretion of soluble mediators, including nitric oxide or interleukin-6, transforming growth factor-beta, human leukocyte antigen G5, and prostaglandin E2. MSCs in the bone marrow are in close contact with T and B cells and regulate immunological memory by organizing defined numbers of dedicated survival niches for plasma cells and memory T cells in the bone marrow. All of these biological effects are probably shared by all stromal cells, including fibroblasts and stem cells isolated from exfoliated deciduous teeth. The therapeutical implications are discussed. http://stemcellres.com/content/1/2/15 Christian Jorgensen Stem Cell Research & Therapy 2010, 1:15 2010-06-08T00:00:00Z doi:10.1186/scrt15 Stem Cell Research & Therapy 1757-6512 1 15 2010-06-08T00:00:00Z XML Human prostate adenocarcinoma is a multicentric disease with histological heterogeneity and variation in biological features. The present study showed that a cell with stem properties undergoing oncogenic transformation can produce prostate mouse lesions with varied histological phenotypes that resemble different grades of human prostate cancer. This powerful observation is consistent with the notion that a complex spectrum of prostate neoplasms may arise from a common cell of origin, facilitating future studies to understand the development of prostate disease. Even so, it must be noted that there is no conclusive evidence that stem cells are the source of human prostate cancer, and therefore additional studies are required comparing features and natural history of tumors generated by this approach with the process of oncogenesis in the human prostate. http://stemcellres.com/content/1/2/16 Letitia Wong Wade Bushman Stem Cell Research & Therapy 2010, 1:16 2010-06-08T00:00:00Z doi:10.1186/scrt16 Stem Cell Research & Therapy 1757-6512 1 16 2010-06-08T00:00:00Z XML Stem cells maintain homeostasis in adult tissues via self-renewal and generation of terminally differentiated cells. Alterations in this intricate balance can result in disease. It has become increasingly evident that cancer can be initiated at the level of stem cells. Therefore, understanding what causes stem cells to become cancerous may lead to new therapeutic approaches. Multiple signaling pathways ultimately affect stem cell survival and proliferation, thus maintaining homeostasis in the gut. Changes in these pathways could perturb normal stem cell behavior, leading to cancerous stem cells. In addition, cancerous stem cells show resistance to current therapies and may lead to a dangerous selection process resulting in recurrence and metastasis. Genomic instability, the driving force of mutation and resistance, may give cancerous stem cells an adaptive advantage, especially when subjected to cancer therapies. Targeting the unique characteristics of cancerous stem cells to promote either terminal differentiation or destruction would effectively eradicate cancer and improve patient care and survival. http://stemcellres.com/content/1/2/13 Julie Chandler Eric Lagasse Stem Cell Research & Therapy 2010, 1:13 2010-05-20T00:00:00Z doi:10.1186/scrt13 Stem Cell Research & Therapy 1757-6512 1 13 2010-05-20T00:00:00Z XML