|  |  |  | | | | | pubmed: "regenerative medici... | | | | | | | | | | | | | | | | | | | High-Efficiency Induction of Neural Conversion in hESCs and hiPSCs with a Single Chemical Inhibitor of TGF-beta Superfamily Receptors. Stem Cells. 2010 Aug 23; Authors: Zhou J, Su P, Li D, Tsang S, Duan E, Wang F Chemical compounds have emerged as powerful tools for modulating embryonic stem cell (ESC) functions and deriving induced pluripotent stem cells (iPSCs), but documentation of compound-induced efficient directed differentiation in human ESC (hESCs) and human iPSC (hiPSCs) is limited. By screening a collection of chemical compounds, we identified compound C (also denoted as dorsomorphin), a protein kinase inhibitor, as a potent regulator of hESC and hiPSC fate decisions. Compound C suppresses mesoderm, endoderm and trophoectoderm differentiation and induces rapid and high-efficiency neural conversion in both hESCs and hiPSCs (88.7% and 70.4%, respectively). Interestingly, compound C is ineffective in inducing neural conversion in mouse ESCs (mESCs). Large-scale kinase assay revealed that compound C targets at least seven TGF-beta superfamily receptors, including both type I and type II receptors, and thereby blocks both the Activin and BMP signaling pathways in hESCs. Dual inhibition of Activin and BMP signaling accounts for the effects of compound C on hESC differentiation and neural conversion. We also identified muscle segment homeobox gene 2 (MSX2) as a downstream target gene of compound C and a key signaling intermediate of the BMP pathway in hESCs. Our findings provide a single-step cost-effective method for efficient derivation of neural progenitor cells in adherent culture from human pluripotent stem cells. Therefore, it will be uniquely suitable for the production of neural progenitor cells in large scale and should facilitate the use of stem cells in drug screening and regenerative medicine and study of early human neural development. PMID: 20734356 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Ageing and neurodegenerative diseases. Ageing Res Rev. 2010 Aug 20; Authors: Hung CW, Chen YC, Hsieh WL, Chiou SH, Kao CL Ageing, which all creatures must encounter, is a challenge to every living organism. In the human body, it is estimated that cell division and metabolism occurs exuberantly until about 25 years of age. Beyond this age, subsidiary products of metabolism and cell damage accumulate, and the phenotypes of ageing appear, causing disease formation. Among these age-related diseases, neurodegenerative diseases have drawn a lot of attention due to their irreversibility, lack of effective treatment, and accompanied social and economical burdens. In seeking to ameliorate ageing and age-related diseases, the search for anti-ageing drugs has been of much interest. Numerous studies have shown that the plant polyphenol, resveratrol (3,5,4'-trihydroxystilbene), extends the lifespan of several species, prevents age-related diseases, and possesses anti-inflammatory, and anti-cancer properties. The beneficial effects of resveratrol are believed to be associated with the activation of a longevity gene, SirT1. In this review, we discuss the pathogenesis of age-related neurodegenerative diseases including Alzheimer's disease, Parkinson's disease and cerebrovascular disease. The therapeutic potential of resveratrol, diet and the roles of stem cell therapy are discussed to provide a better understanding of the ageing mystery. PMID: 20732460 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Dynamics of Bone Marrow-Derived Endothelial Progenitor Cell/Mesenchymal Stem Cell Interaction in Co-culture and its Implications in Angiogenesis. Biochem Biophys Res Commun. 2010 Aug 20; Authors: Aguirre A, Planell JA, Engel E Tissue engineering aims to regenerate tissues and organs by using cell and biomaterial-based approaches. One of the current challenges in the field is to promote proper vascularization in the implant to prevent cell death and promote host integration. Bone marrow endothelial progenitor cells (BM-EPCs) and mesenchymal stem cells (MSCs) are bone marrow resident stem cells widely employed for proangiogenic applications. In vivo, they are likely to interact frequently both in the bone marrow and at sites of injury. In this study, the physical and biochemical interactions between BM-EPCs and MSCs in an in vitro co-culture system were investigated to further clarify their roles in vascularization. BM-EPC/MSC co-cultures established close cell-cell contacts soon after seeding and self-assembled to form elongated structures at 3 days. Besides direct contact, cells also exhibited vesicle transport phenomena. When co-cultured in Matrigel, tube formation was greatly enhanced even in serum-starved, growth factor free medium. Both MSCs and BM-EPCs contributed to these tubes. However, cell proliferation was greatly reduced in co-culture and morphological differences were observed. Gene expression and cluster analysis for wide panel of angiogenesis-related transcripts demonstrated up-regulation of angiogenic markers but down-regulation of many other cytokines. These data suggest that cross-talk occurs in between BM-EPCs and MSCs through paracrine and direct cell contact mechanisms leading to modulation of the angiogenic response. PMID: 20732306 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Immunomodulatory Properties of Mesenchymal Stem Cells Derived from Dental Pulp and Dental Follicle are Susceptible to Activation by Toll-Like Receptor Agonists. Stem Cells Dev. 2010 Aug 23; Authors: Tomic S, Djokic J, Vasilijic S, Vucevic D, Todorovic V, Supic G, Colic M Adult mesenchymal stem cells (MSCs) have recently become a potent tool in regenerative medicine. Due to certain shortcomings of obtaining bone marrow MSCs, alternate sources of MSCs have been sought. In this work we studied MSCs from dental pulp (DP-MSCs) and dental follicle (DF-MSCs), isolated from the same tooth/donor, in order to define differences in their phenotypic properties, differentiation potential and immunomodulatory activities. Both cell types showed colony forming ability and expressed typical MSCs markers, but differed in the levels of their expression. DF-MSCs proliferated faster, contained cells larger in diameter, exhibited a higher potential to form adipocytes and a lower potential to form chondrocytes and osteoblasts, compared to DP-MSCs. In contrast to DF-MSCs, DP-MSCs produced the transforming growth factor (TGF)-beta and suppressed proliferation of peripheral blood mononuclear cells, which could be neutralized with anti-TGF-beta antibody. The treatment with TLR3 agonist augmented the suppressive potential of both cell types and potentiated TGF-beta and interleukin (IL)-6 secretions by these cells. TLR4 agonist augmented the suppressive potential of DF-MSCs and increased TGF-beta production, but abrogated the immunosuppressive activity of DP-MSCs by inhibiting TGF-beta production and the expression of indolamine-2,3-dioxygenase-1. Some of these effects correlated with the higher expression of TLR3 and TLR4 by DP-MSCs compared to DF-MSCs. When transplanted in imunocompetent xenogenic host, both cell types induced formation of granulomatous tissue. In conclusion, our results suggest that dental MSCs are functionally different and each of these functions should be further explored in vivo prior to their specific biomedical applications. PMID: 20731536 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Progressing study in osteoblasts cultured in vitro] Zhongguo Gu Shang. 2010 Jul;23(7):562-5 Authors: Xu YJ, Zhao JN With the development of cell culture technology in vitro, people have successfully cultivated osteoblast cells of typical characteristics from a number of animal skull, bone marrow, periosteum and bone tissues; studies have shown that these osteoblasts have good biological characteristics, can create bone tissue in different environments, can apply joint stand for the construction of tissue engineered bone, be implanted in the body to repair bone defects. In this article, the source of osteoblast, regulatory factor, composite graft and Chinese medicine research progress were reviewed. PMID: 20701143 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Regeneration of the articular surface of the rabbit synovial joint by cell homing: a proof of concept study. Lancet. 2010 Aug 7;376(9739):440-8 Authors: Lee CH, Cook JL, Mendelson A, Moioli EK, Yao H, Mao JJ BACKGROUND: A common approach for tissue regeneration is cell delivery, for example by direct transplantation of stem or progenitor cells. An alternative, by recruitment of endogenous cells, needs experimental evidence. We tested the hypothesis that the articular surface of the synovial joint can regenerate with a biological cue spatially embedded in an anatomically correct bioscaffold. METHODS: In this proof of concept study, the surface morphology of a rabbit proximal humeral joint was captured with laser scanning and reconstructed by computer-aided design. We fabricated an anatomically correct bioscaffold using a composite of poly-varepsilon-caprolactone and hydroxyapatite. The entire articular surface of unilateral proximal humeral condyles of skeletally mature rabbits was surgically excised and replaced with bioscaffolds spatially infused with transforming growth factor beta3 (TGFbeta3)-adsorbed or TGFbeta3-free collagen hydrogel. Locomotion and weightbearing were assessed 1-2, 3-4, and 5-8 weeks after surgery. At 4 months, regenerated cartilage samples were retrieved from in vivo and assessed for surface fissure, thickness, density, chondrocyte numbers, collagen type II and aggrecan, and mechanical properties. FINDINGS: Ten rabbits received TGFbeta3-infused bioscaffolds, ten received TGFbeta3-free bioscaffolds, and three rabbits underwent humeral-head excision without bioscaffold replacement. All animals in the TGFbeta3-delivery group fully resumed weightbearing and locomotion 3-4 weeks after surgery, more consistently than those in the TGFbeta3-free group. Defect-only rabbits limped at all times. 4 months after surgery, TGFbeta3-infused bioscaffolds were fully covered with hyaline cartilage in the articular surface. TGFbeta3-free bioscaffolds had only isolated cartilage formation, and no cartilage formation occurred in defect-only rabbits. TGFbeta3 delivery yielded uniformly distributed chondrocytes in a matrix with collagen type II and aggrecan and had significantly greater thickness (p=0.044) and density (p<0.0001) than did cartilage formed without TGFbeta3. Compressive and shear properties of TGFbeta3-mediated articular cartilage did not differ from those of native articular cartilage, and were significantly greater than those of cartilage formed without TGFbeta3. Regenerated cartilage was avascular and integrated with regenerated subchondral bone that had well defined blood vessels. TGFbeta3 delivery recruited roughly 130% more cells in the regenerated articular cartilage than did spontaneous cell migration without TGFbeta3. INTERPRETATION: Our findings suggest that the entire articular surface of the synovial joint can regenerate without cell transplantation. Regeneration of complex tissues is probable by homing of endogenous cells, as exemplified by stratified avascular cartilage and vascularised bone. Whether cell homing acts as an adjunctive or alternative approach of cell delivery for regeneration of tissues with different organisational complexity warrants further investigation. FUNDING: New York State Stem Cell Science; US National Institutes of Health. PMID: 20692530 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Spinal effects of the fesoterodine metabolite 5-hydroxymethyl tolterodine and/or doxazosin in rats with or without partial urethral obstruction. J Urol. 2010 Aug;184(2):783-9 Authors: Füllhase C, Soler R, Gratzke C, Brodsky M, Christ GJ, Andersson KE PURPOSE: The combination of muscarinic receptor and alpha(1)-adrenoceptor antagonists is increasingly used for benign prostatic hyperplasia related lower urinary tract symptoms. In addition to the well established peripheral site of action, little is known about the central effects of muscarinic receptor antagonists and muscarinic receptor/alpha(1)-adrenoceptor antagonist combinations on bladder function, partly due to poor brain penetration after systemic administration. We assessed the effects of intrathecal 5-hydroxymethyl tolterodine, an active metabolite of fesoterodine, in obstructed and nonobstructed rats, and of combined intrathecal 5-hydroxymethyl tolterodine/doxazosin in a rat model of partial urethral obstruction. MATERIALS AND METHODS: We used 80 male Sprague-Dawley rats to test various doses of intrathecal 5-hydroxymethyl tolterodine and/or intrathecal doxazosin on urodynamic parameters. Urodynamic evaluation without anesthesia was done 3 days after bladder and intrathecal catheterization. Two weeks before urodynamics 40 rats underwent partial urethral obstruction. RESULTS: Intrathecal 5-hydroxymethyl tolterodine had no urodynamic effects in nonobstructed rats. Compared to controls obstructed rats had increased bladder pressure and weight, and voiding frequency. In obstructed rats 5-hydroxymethyl tolterodine restored urodynamic parameters to those seen in nonobstructed animals. Doxazosin had effects similar to those of intrathecal 5-hydroxymethyl tolterodine. When the 2 drugs were combined, at the doses used only small additional effects were observed. CONCLUSIONS: Urodynamic changes in obstructed rats can be normalized by intrathecal 5-hydroxymethyl tolterodine and by intrathecal doxazosin. The central pathways on which the 2 drugs act seem to be up-regulated with partial urethral obstruction and less relevant under normal conditions. PMID: 20639056 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Minced urothelium to create epithelialized subcutaneous conduits. J Urol. 2010 Aug;184(2):757-61 Authors: Fossum M, Zuhaili B, Bergmann J, Spielmann M, Hirsch T, Eriksson E PURPOSE: We used in vivo cell expansion to create 3-dimensional subcutaneous conduits lined with an inner layer of autologous urothelial mucosa. MATERIALS AND METHODS: Laparotomy and excision of a fifth of the bladder were done in 5 female Yorkshire pigs (Parsons Farm, Westhampton, Massachusetts) under general anesthesia. After mechanical removal of the detrusor muscle the bladder mucosa was minced to obtain 0.2 x 0.8 x 0.8 mm particles, which were attached to the outer surface of latex tubes using a thin layer of fibrin glue. Seven to 10 tubes were placed in the abdominal wall subcutaneous tissue in each original donor pig with tubes lacking particles serving as controls. Biopsy was done 1 to 4 weeks after transplantation for histological evaluation. RESULTS: One week after transplantation particles were still present in the granulation tissue. At 2 weeks the epithelium was differentiated with transitional uroepithelium facing the lumen, ie toward the tube. No epithelium was detected around control tubes. CONCLUSIONS: After autologous transplantation of bladder mucosal particles organized in 3-dimensional fashion in pig subcutaneous tissue the transplanted cells proliferated, migrated and reorganized to form a continuous epithelial lining facing the lumen. This novel approach to urothelial transplantation may allow successful formation of a conduit to the bladder or of a neourethra. PMID: 20639052 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Germline self-renewal requires cyst stem cells and stat regulates niche adhesion in Drosophila testes. Nat Cell Biol. 2010 Aug;12(8):806-11 Authors: Leatherman JL, Dinardo S Adults maintain tissue-specific stem cells through niche signals. A model for niche function is the Drosophila melanogaster testis, where a small cluster of cells called the hub produce locally available signals that allow only adjacent cells to self-renew. We show here that the principal signalling pathway implicated in this niche, chemokine activation of STAT, does not primarily regulate self-renewal of germline stem cells (GSCs), but rather governs GSC adhesion to hub cells. In fact, GSC renewal does not require hub cell contact, as GSCs can be renewed solely by contact with the second resident stem cell population, somatic cyst stem cells (CySCs), and this involves BMP signalling. These data suggest a modified paradigm whereby the hub cells function as architects of the stem cell environment, drawing into proximity cellular components necessary for niche function. Self-renewal functions are shared by the hub cells and the CySCs. This work also reconciles key differences in GSC renewal between Drosophila testis and ovary niches, and highlights how a niche can coordinate the production of distinct lineages by having one stem cell type rely on a second. PMID: 20622868 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Functional heterogeneity of embryonic stem cells revealed through translational amplification of an early endodermal transcript. PLoS Biol. 2010;8(5):e1000379 Authors: Canham MA, Sharov AA, Ko MS, Brickman JM ES cells are defined as self-renewing, pluripotent cell lines derived from early embryos. Cultures of ES cells are also characterized by the expression of certain markers thought to represent the pluripotent state. However, despite the widespread expression of key markers such as Oct4 and the appearance of a characteristic undifferentiated morphology, functional ES cells may represent only a small fraction of the cultures grown under self-renewing conditions. Thus phenotypically "undifferentiated" cells may consist of a heterogeneous population of functionally distinct cell types. Here we use a transgenic allele designed to detect low level transcription in the primitive endoderm lineage as a tool to identify an immediate early endoderm-like ES cell state. This reporter employs a tandem array of internal ribosomal entry sites to drive translation of an enhanced Yellow Fluorescent Protein (Venus) from the transcript that normally encodes for the early endodermal marker Hex. Expression of this Venus transgene reports on single cells with low Hex transcript levels and reveals the existence of distinct populations of Oct4 positive undifferentiated ES cells. One of these cells types, characterized by both the expression of the Venus transgene and the ES cells marker SSEA-1 (V(+)S(+)), appears to represent an early step in primitive endoderm specification. We show that the fraction of cells present within this state is influenced by factors that both promote and suppress primitive endoderm differentiation, but conditions that support ES cell self-renewal prevent their progression into differentiation and support an equilibrium between this state and at least one other that resembles the Nanog positive inner cell mass of the mammalian blastocysts. Interestingly, while these subpopulations are equivalently and clonally interconvertible under self-renewing conditions, when induced to differentiate both in vivo and in vitro they exhibit different behaviours. Most strikingly when introduced back into morulae or blastocysts, the V(+)S(+) population is not effective at contributing to the epiblast and can contribute to the extra-embryonic visceral and parietal endoderm, while the V(-)S(+) population generates high contribution chimeras. Taken together our data support a model in which ES cell culture has trapped a set of interconvertible cell states reminiscent of the early stages in blastocyst differentiation that may exist only transiently in the early embryo. PMID: 20520791 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Human satellite progenitor cells for use in myofascial repair: isolation and characterization. Ann Plast Surg. 2010 Jun;64(6):794-9 Authors: Logan MS, Propst JT, Nottingham JM, Goodwin RL, Pabon DF, Terracio L, Yost MJ, Fann SA Current use of prosthetic meshes and implants for myofascial reconstruction has been associated with infectious complications, long-term failure, and dissatisfying cosmetic results. Our laboratory has developed a small animal model for ventral hernia repair, which uses progenitor cells isolated from a skeletal muscle biopsy. In the model, progenitor cells are expanded in vitro, seeded onto a nonimmunogenic, novel aligned scaffold of bovine collagen and placed into the defect as a living adjuvant to the innate repair mechanism. The purpose of the current investigation is to examine the feasibility of translating our current model to humans. As a necessary first step we present our study on the efficacy of isolating satellite cells from 9 human donor biopsies. We were able to successfully translate our progenitor cell isolation and culture protocols to a human model with some modifications. Specifically, we have isolated human satellite muscle cells, expanded them in culture, and manipulated these cells to differentiate into myotubes in vitro. Immunohistochemical analysis allowed the characterization of distinct progenitor cell cycle stages and quantification of approximate cell number. Furthermore, isolated cells were tracked via cytoplasmic nanocrystal labeling and observed using confocal microscopy. PMID: 20407365 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | The effect of "minimally invasive transfer of angiosomes" on vascularization of prefabricated/prelaminated tissues. Ann Plast Surg. 2010 Apr;64(4):491-5 Authors: Demirtas Y, Engin MS, Aslan O, Ayas B, Karacalar A Prefabrication and prelamination are experimental and clinical applications of reconstructive surgery and inspired the vascularization challenge of engineered tissues. The purpose of this study is to test the efficiency of "minimally invasive transfer of angiosomes" to enhance the vascularization of the final construct during prefabrication and prelamination. Fifteen rabbits were used for this study. Three of the animals were used in a pilot study to develop the protocol. During the study, thoracodorsal and lateral thoracic vascular pedicles on each side constituted 4 study groups. The pedicles were prepared to simulate prelamination with and without transfer of angiosomes, and prefabrication with and without transfer of angiosomes. In all of the groups, a 10 x 15 mm auricular cartilage graft was used as the construct to be vascularized. After 2 weeks, vascularization of the grafts was evaluated by means of microangiography and histology. Results indicate that both prelamination and prefabrication with transfer of angiosomes displayed better vascularization, both qualitatively and quantitatively. However, prelamination with transfer of angiosomes group displayed distinct statistical superiority. The results suggest that minimally invasive transfer of angiosomes coupled with the procedure significantly increases the induction of angiogenesis during prelamination and prefabrication. PMID: 20224348 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Stromal hyaluronan interaction with epithelial CD44 variants promotes prostate cancer invasiveness by augmenting expression and function of hepatocyte growth factor and androgen receptor. J Biol Chem. 2010 Jun 25;285(26):19821-32 Authors: Ghatak S, Hascall VC, Markwald RR, Misra S The main aim of our study is to determine the significance of the stromal microenvironment in the malignant behavior of prostate cancer. The stroma-derived growth factors/cytokines and hyaluronan act in autocrine/paracrine ways with their receptors, including receptor-tyrosine kinases and CD44 variants (CD44v), to potentiate and support tumor epithelial cell survival. Overexpression of hyaluronan, CD44v9 variants, and stroma-derived growth factors/cytokines are specific features in many cancers, including prostate cancer. Androgen/androgen receptor interaction has a critical role in regulating prostate cancer growth. Our previous study showed that 1) that increased synthesis of hyaluronan in normal epithelial cells promotes expression of CD44 variants; 2) hyaluronan interaction with CD44v6-v9 promotes activation of receptor-tyrosine kinase, which stimulates phosphatidylinositol 3-kinase-induced cell survival pathways; and 3) CD44v6/short hairpin RNA reduces colon tumor growth in vivo (Misra, S., Hascall, V. C., De Giovanni, C., Markwald, R. R., and Ghatak, S. (2009) J. Biol. Chem. 284, 12432-12446). Our results now show that hepatocyte growth factor synthesized by myofibroblasts associated with prostate cancer cells induces activation of HGF-receptor/cMet and stimulates hyaluronan/CD44v9 signaling. This, in turn, stabilizes the androgen receptor functions in prostate cancer cells. The stroma-derived HGF induces a lipid raft-associated signaling complex that contains CD44v9, cMet/phosphatidylinositol 3-kinase, HSP90 and androgen receptor. CD44v9/short hairpin RNA reverses the assembly of these components in the complex and inhibits androgen receptor function. Our results provide new insight into the hyaluronan/CD44v9-regulated androgen receptor function and the consequent malignant activities in prostate cancer cells. The present study describes a physiologically relevant in vitro model for studying the molecular mechanisms by which stroma-derived HGF and hyaluronan influence androgen receptor and CD44 functions in the secretory epithelia during prostate carcinogenesis. PMID: 20200161 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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