| FIBROBLAST GROWTH FACTOR-2 ENHANCES PROLIFERATION AND DELAYS LOSS OF CHONDROGENIC POTENTIAL IN HUMAN ADULT BONE MARROW-DERIVED MESENCHYMAL STEM CELLS.
October 22, 2009 at 9:50 am
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| | FIBROBLAST GROWTH FACTOR-2 ENHANCES PROLIFERATION AND DELAYS LOSS OF CHONDROGENIC POTENTIAL IN HUMAN ADULT BONE MARROW-DERIVED MESENCHYMAL STEM CELLS. Tissue Eng Part A. 2009 Oct 20; Authors: Solchaga LA, Penick K, Goldberg VM, Caplan AI, Welter JF We compared human mesenchymal stem cells (hMSCs), expanded long-term with and without fibroblast growth factor (FGF) supplementation, with respect to proliferation, and ability to undergo chondrogenesis in vitro. hMSCs expanded in FGF-supplemented medium proliferated more rapidly than control cells. Aggregates of FGF-treated cells exhibited chondrogenic differentiation at all passages tested although, in some preparations, differentiation was diminished after seventh passage. Aggregates made with control cells differentiated along the chondrogenic lineage after first passage but exhibited only marginal differentiation after fourth and failed to form cartilage after seventh passage. Microarray analysis of gene expression identified 334 transcripts differentially expressed in fourth passage control cells which had reduced chondrogenic potential, compared to fourth passage FGF-treated cells which retained this capacity, and 243 transcripts that were differentially expressed when comparing them to first passage control cells which were also capable of differentiating into chondrocytes. The intersection of these analyses yielded 49 transcripts differentially expressed in cells that exhibited chondrogenic differentiation in vitro compared to cells that did not. Among these, ANGPT1, SFRP1 and STEAP1 appear to be of higher relevance. These preliminary data must now be validated to verify whether different gene expression profiles translate into functional differences. In sum, these findings suggest that the chondrogenic potential of hMSCs is vulnerable to cell expansion and that care should be exercised when expanding these cells for cartilage tissue engineering applications. Supplementation with FGF-2 allows reaching target cell numbers more rapidly and extends the level of expansion within which these cells are useful for tissue-engineered cartilage repair. PMID: 19842915 [PubMed - as supplied by publisher] |
| Enhancement of Long-term Proliferative Capacity of Rabbit Corneal Epithelial Cells by Embryonic Stem Cell Conditioned Medium.
October 22, 2009 at 9:50 am
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| | Enhancement of Long-term Proliferative Capacity of Rabbit Corneal Epithelial Cells by Embryonic Stem Cell Conditioned Medium. Tissue Eng Part C Methods. 2009 Oct 20; Authors: Liu Y, Ma P, Wu Z, Duan H, Ding Y, Liu Z, Wan P, Lu X, Xiang P, Ge J, Wang Z Induction of autologous stem cells for directed differentiation has become predominant methods to obtain autologous cells for tissue reconstruction. However, the low inducing efficiency and contamination with other type of cells hinder its clinical utilization. Here we report a novel phenomenon that the corneal epithelial cells maintain long-term proliferative capacity and tissue-specific cell phenotype by factors secreted from murine embryonic stem cells (ESC). The rabbit corneal epithelial cells grew very well in culture medium with addition of 40% ESC conditioned medium (ESC-CM). These corneal epithelial cells have been serially subcultured for more than 20 passages and maintained high cell purity, cobble-stone-like morphology, enhanced colony forming efficiency, normal diploid, and capacity to regenerate a functional stratified corneal epithelial equivalent. More importantly, these cells did not form tumor, and the cells lost their proliferative capacity after withdrawal of ESC-CM. The long-term proliferative capacity of corneal epithelial cells is partly resulted from enhancement of cell survival and colony formation, and mediated by ectopic expression of telomerase. Our findings indicate that this new ESC-CM culture system can generate low-immunogenic autologous cells sufficiently for use in regenerative medicine. PMID: 19842914 [PubMed - as supplied by publisher] |
| Multifunctional Superparamagnetic Janus Particles.
October 22, 2009 at 9:50 am
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| | Multifunctional Superparamagnetic Janus Particles. Langmuir. 2009 Oct 20; Authors: Yuet KP, Hwang DK, Haghgooie R, Doyle PS In this study, we report the microfluidic-based synthesis of a multifunctional Janus hydrogel particle with anisotropic superparamagnetic properties and chemical composition for the bottom-up assembly of hydrogel superstructures. In a uniform magnetic field, the resulting Janus magnetic particles fabricated in the present method exhibit chainlike or meshlike superstructure forms, the complexity of which can be simply modulated by particle density and composition. This controllable field-driven assembly of the particles can be potentially used as building blocks to construct targeted superstructures for tissue engineering. More importantly, we demonstrated that this method also shows the ability to generate multifunctional Janus particles with great design flexibilities: (a) direct encapsulation and precise spatial distribution of biological substance and (b) selective surface functionalization in a particle. Although these monodisperse particles find immediate use in tissue engineering, their ability to self-assemble with tunable anisotropic configurations makes them an intriguing material for several exciting areas of research such as photonic crystals, novel microelectronic architecture, and sensing. PMID: 19842632 [PubMed - as supplied by publisher] |
| [An experimental study of using chitinous membrane as the culture scaffold for epidermal stem cells]
October 22, 2009 at 9:50 am
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| | [An experimental study of using chitinous membrane as the culture scaffold for epidermal stem cells] Zhonghua Shao Shang Za Zhi. 2009 Jun;25(3):197-201 Authors: Shen Y, Li XJ, Liang R, Li YC, Zhang Y, Liang PH, Dai LB, Yang XH, Tan JR, Li YY, Huang Y OBJECTIVE: To investigate the feasibility of constructing a skin tissue engineering covering on chitinous membrane using rat epidermal stem cells (ESCs). METHODS: Rat ESCs were isolated and cultured by cold digestive method and collagen type IV adherent method. Cell colonies were observed with inverted microscope. Expressions of DNA and RNA of ESCs were detected with laser scanning confocal microscope. Growth curves of cells were determined with Alamar BlueTM colorimetric method. Expressions of surface markers of ESCs (CD29, CD71, CD49d, and CD34) were detected with flow cytometer. Positive expressions of CK15, CK19, and P63 of ESCs were determined by immunohistochemistry. Influence of original chitinous membrane leachate in different dilutions on ESCs was observed. Condition of growth of ESCs on the vehicle was observed. RESULTS: Isolated cultured cells were verified as ESCs, of which the doubling generation time was 48 hs. CD29 and CD49d were positive; CD71 and CD34 were negative; CK19, CK15, and P63 were positive. Compared with that of control group, ESCs cultured in chitinous membrane leachate showed slight cell proliferation when diluted to 1:8-1:512 dilutions, but there was no statistically significant difference (P > 0.05). The checkerboard-form cell colonies of ESCs could be visualized with naked eyes on the chitinous membrane in 2-4 weeks of culture. A multitude of ESCs were seen to grow on fibres under microscope. CONCLUSIONS: Chitinous membrane may be used as ESCs culture vehicle, and biological compatibility is good. PMID: 19842556 [PubMed - in process] |
| The ISSCR: who are we and where are we going?
October 22, 2009 at 9:50 am
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| | The ISSCR: who are we and where are we going? Cell Stem Cell. 2009 Aug 7;5(2):151-3 Authors: Weissman I PMID: 19664988 [PubMed - indexed for MEDLINE] |
| Adult muscle stem cells avoid death and Paxes.
October 22, 2009 at 9:50 am
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| | Adult muscle stem cells avoid death and Paxes. Cell Stem Cell. 2009 Aug 7;5(2):132-4 Authors: Brack A In a recent Nature publication, Lepper et al. (2009) use cell-specific lineage tracing and temporally controllable gene deletion approaches to study muscle stem cell function and reveal age-dependent requirements for Pax gene expression. PMID: 19664985 [PubMed - indexed for MEDLINE] |
| Bin1 SRC homology 3 domain acts as a scaffold for myofiber sarcomere assembly.
October 22, 2009 at 9:50 am
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| | Bin1 SRC homology 3 domain acts as a scaffold for myofiber sarcomere assembly. J Biol Chem. 2009 Oct 2;284(40):27674-86 Authors: Fernando P, Sandoz JS, Ding W, de Repentigny Y, Brunette S, Kelly JF, Kothary R, Megeney LA In skeletal muscle development, the genes and regulatory factors that govern the specification of myocytes are well described. Despite this knowledge, the mechanisms that regulate the coordinated assembly of myofiber proteins into the functional contractile unit or sarcomere remain undefined. Here we explored the hypothesis that modular domain proteins such as Bin1 coordinate protein interactions to promote sarcomere formation. We demonstrate that Bin1 facilitates sarcomere organization through protein-protein interactions as mediated by the Src homology 3 (SH3) domain. We observed a profound disorder in myofiber size and structural organization in a murine model expressing the Bin1 SH3 region. In addition, satellite cell-derived myogenesis was limited despite the accumulation of skeletal muscle-specific proteins. Our experiments revealed that the Bin1 SH3 domain formed transient protein complexes with both actin and myosin filaments and the pro-myogenic kinase Cdk5. Bin1 also associated with a Cdk5 phosphorylation domain of titin. Collectively, these observations suggest that Bin1 displays protein scaffold-like properties and binds with sarcomeric factors important in directing sarcomere protein assembly and myofiber maturation. PMID: 19633357 [PubMed - indexed for MEDLINE] |
| Activity-Dependent Neuroprotective Protein (ADNP) Expression in the Amyloid Precursor Protein/Presenilin 1 Mouse Model of Alzheimer's Disease.
October 22, 2009 at 9:50 am
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| | Activity-Dependent Neuroprotective Protein (ADNP) Expression in the Amyloid Precursor Protein/Presenilin 1 Mouse Model of Alzheimer's Disease. J Mol Neurosci. 2009 Oct 21; Authors: Fernandez-Montesinos R, Torres M, Baglietto-Vargas D, Gutierrez A, Gozes I, Vitorica J, Pozo D A major determinant in the pathogenesis of Alzheimer's disease (AD) is the deposition of beta-amyloid (Abeta) peptides in specific areas of the central nervous system. Therefore, animal models of Alzheimer amyloidosis are excellent tools to identify candidates to facilitate drug screening and to understand the molecular pathology of AD. Activity-dependent neuroprotective protein (ADNP) plays an essential role in brain development, and NAP (NAPVSIPQ, generic name: davunetide)-a peptide derived from ADNP-is currently in clinical development for the treatment of neurodegenerative disorders. However, the link between ADNP expression and AD remains unexplored. To test whether ADNP is affected by the onset of AD and progression, we employed the PS1xAPP mouse model (PS1(M146L) x APP(751SL) transgenic mice) to analyze the mRNA expression of ADNP in the hippocampus and cerebellum in early and advanced stages of disease. Results showed that ADNP expression in 6-month-old PS1xAPP mice hippocampus was higher than in wild-type (WT) mice. ADNP was originally identified as a vasoactive intestinal peptide (VIP)-responsive gene taking part in the VIP-mediated neurotrophic pathway. Interestingly, the expression of VIP was not affected in the same experimental setting, suggesting that ADNP expression is a VIP-independent marker associated with AD. Moreover, in the cerebellum, a brain area not affected by Abeta deposition, ADNP mRNA expression in 6-month-old PS1xAPP and WT were not different. A similar extent of hippocampal ADNP expression was observed in 18-month-old WT and PS1xAPP mice, in contrast to the differential expression level at 6 months of age. However, hippocampal ADNP expression in both WT and PS1xAPP was increased with aging similar to VIP mRNA expression. Our findings support the hypothesis that ADNP expression is related to early or mild AD progression by a VIP-independent mechanism. PMID: 19844808 [PubMed - as supplied by publisher] |
| A validated model of GAG deposition, cell distribution and growth of tissue engineered cartilage cultured in a rotating bioreactor.
October 22, 2009 at 4:50 am
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| | A validated model of GAG deposition, cell distribution and growth of tissue engineered cartilage cultured in a rotating bioreactor. Biotechnol Bioeng. 2009 Oct 20; Authors: Nikolaev NI, Obradovic B, Versteeg HK, Lemon G, Williams DJ In this work a new phenomenological model of growth of cartilage tissue cultured in a rotating bioreactor is developed. It represents an advancement of a previously derived model of deposition of glycosaminoglycan (GAG) in engineered cartilage by (i) introduction of physiological mechanisms of proteoglycan accumulation in the extracellular matrix (ECM) as well as by correlating (ii) local cell densities and (iii) tissue growth to the ECM composition. In particular, previously established predictions and correlations of local oxygen concentrations and GAG synthesis rates are extended to distinguish cell secreted proteoglycan monomers free to diffuse in cell surroundings and outside from the engineered construct, from large aggrecan molecules, which are constrained within the ECM and practically immovable. The model includes kinetics of aggregation i.e. transformation of mobile GAG species into immobile aggregates as well as maintenance of the normal ECM composition after the physiological GAG concentration is reached by incorporation of a product inhibition term. The model also includes mechanisms of the temporal evolution of cell density distributions and tissue growth under in vitro conditions. After a short initial proliferation phase the total cell number in the construct remains constant, but the local cell distribution is levelled out by GAG accumulation and repulsion due to negative molecular charges. Furthermore, strong repulsive forces result in expansion of the local tissue elements observed macroscopically as tissue growth (i.e. construct enlargement). The model is validated by comparison with experimental data of (i) GAG distribution and leakage, (ii) spatial-temporal distributions of cells and (iii) tissue growth reported in previous works. Validation of the model predictive capability - against a selection of measured data that were not used to construct the model - suggests that the model successfully describes the interplay of several simultaneous processes carried out during in vitro cartilage tissue regeneration and indicates that this approach could also be attractive for application in other tissue engineering systems. (c) 2009 Wiley Periodicals, Inc. PMID: 19845002 [PubMed - as supplied by publisher] | | | 
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