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Research Containing: mesenchymal stem cells

Could the effect of modeled microgravity on osteogenic differentiation of human mesenchymal stem cells be reversed by regulation of signaling pathways?

by on 9 June 2015in Biology & Biotechnology No comment

Microgravity (MG) results in a reduction in bone formation. Bone formation involves osteogenic differentiation from mesenchymal stem cells (hMSCs) in bone marrow. We modeled MG to determine its effects on osteogenesis of hMSCs and used activators or inhibitors of signaling factors to regulate osteogenic differentiation. Under osteogenic induction, MG reduced osteogenic differentiation of hMSCs and decreased the expression of osteoblast gene markers. The expression of Runx2 was also inhibited, whereas the expression of PPARgamma2 increased. MG also decreased phosphorylation of ERK, but increased phosphorylation of p38MAPK. SB203580, a p38MAPK inhibitor, was able to inhibit the phosphorylation of p38MAPK, but did not reduce the expression of PPARgamma2. Bone morphogenetic protein (BMP) increased the expression of Runx2. Fibroblast growth factor 2 (FGF2) increased the phosphorylation of ERK, but did not significantly increase the expression of osteoblast gene markers. The combination of BMP, FGF2 and SB203580 significantly reversed the effect of MG on osteogenic differentiation of hMSCs. Our results suggest that modeled MG inhibits the osteogenic differentiation and increases the adipogenic differentiation of hMSCs through different signaling pathways. Therefore, the effect of MG on the differentiation of hMSCs could be reversed by the mediation of signaling pathways.

Related URLs:
http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=emed8&AN=2007294544
http://sfxhosted.exlibrisgroup.com/mayo?sid=OVID:embase&id=pmid:&id=doi:10.1515%2FBC.2007.082&issn=1431-6730&isbn=&volume=388&issue=7&spage=755&pages=755-763&date=2007&title=Biological+Chemistry&atitle=Could+the+effect+of+modeled+microgravity+on+osteogenic+differentiation+of+human+mesenchymal+stem+cells+be+reversed+by+regulation+of+signaling+pathways%3F&aulast=Zheng&pid=%3Cauthor%3EZheng+Q.%3C%2Fauthor%3E&%3CAN%3E2007294544%3C%2FAN%3E

Microgravity potentiates stem cell proliferation while sustaining the capability of differentiation

by on 9 June 2015in Biology & Biotechnology No comment

A three-dimensional (3D) clinostat is a device for generating multidirectional G force, resulting in an environment with an average of 10(3) G. Here we report that human mesenchymal stem cells (hMSCs) cultured in a 3D-clinostat (group CL) showed marked proliferation (13-fold in a week) compared with cells cultured under normal conditions of 1 G (group C) (4-fold in a week). Flow cytometry revealed a 6-fold increase in the number of hMSCs double-positive for CD44/CD29 or CD90/CD29 in group CL after 7 days in culture, compared with group C. Telomere length remained the same in cells from both groups during culturing. Group C cells showed increasing expression levels of type II collagen and aggrecan over the culture period, whereas group CL cells showed a decrease to undetectable levels. Pellets of hMSCs from each group were explanted into cartilagedefective mice. The transplants from group CL formed hyaline cartilage after 7 days, whereas the transplants from group C formed only noncartilage tissue containing a small number of cells. These results show that hMSCs cultured in a 3D-clinostat possess the strong proliferative characteristic of stem cells and retain their ability to differentiate into hyaline cartilage after transplantation. On the contrary, cells cultured in a 1-G environment do not maintain these features. Simulated microgravity may thus provide an environment to successfully expand stem cell populations in vitro without culture supplements that can adversely affect stem cell-derived transplantations. This method has significant potential for regenerative medicine and developmental biology.

Related URLs:
http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=emed7&AN=2007051139
http://sfxhosted.exlibrisgroup.com/mayo?sid=OVID:embase&id=pmid:&id=doi:10.1089%2Fscd.2006.15.921&issn=1547-3287&isbn=&volume=15&issue=6&spage=921&pages=921-929&date=2006&title=Stem+Cells+and+Development&atitle=Microgravity+potentiates+stem+cell+proliferation+while+sustaining+the+capability+of+differentiation&aulast=Yuge&pid=%3Cauthor%3EYuge+L.%3C%2Fauthor%3E&%3CAN%3E2007051139%3C%2FAN%3E

Extensive adipogenic and osteogenic differentiation of patterned human mesenchymal stem cells in a microfluidic device

by on 9 June 2015in Biology & Biotechnology No comment

Microtechnology offers great prospects for cellular research by enabling controlled experimental conditions that cannot be achieved by traditional methods. This study demonstrates the use of a microfluidic platform for long-term cultivation (3 weeks) of human mesenchymal stem-like cells (MSCs), a cell population of high interest for tissue engineering. The typical high motility of the MSCs required a strategy for preventing cells from inhabiting the feeding channels and thus interfere with a steady perfusion of medium to the cell cultivation chamber. Hence, a straightforward and long-term patterning method was developed and implemented for reliable cell positioning within the device. This method was based on the modification of a polystyrene substrate into cell supportive and non-supportive regions by the use of selective oxygen plasma treatment and the triblock copolymer Pluronic. Also, a novel and size-effective "flip-chip'' set-up for operating the devices was invented. Successful and reproducible adipogenic and osteogenic differentiation of MSCs in the device was demonstrated, verifying that an adequate long-term microfluidic cultivation environment was obtained. Strengths of the experimental protocol include ease of fabrication and maintenance (gravity driven), good cell performance (viability/differentiation), as well as the possibility of exposing the culture to heterogeneous laminar flow for experimental purposes.

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<Go to ISI>://WOS:000277832800006

Simulated microgravity alters multipotential differentiation of rat mesenchymal stem cells in association with reduced telomerase activity

by on 9 June 2015in Biology & Biotechnology No comment

Microgravity is one of the most important characteristics in space flight. Exposure to microgravity results in extensive physiological changes in humans. Bone loss is one of the changes with serious consequences: however. the mechanism retains unclear. As the origin of osteoprogenitors, mesenchymal stein cells (MSCs) may play an important role in it. After cultured under simulated microgravity (in a rotary cell culture system, RCCS), MSCs were stained using oil red O to identify adipocytes. The mRNA level of bone morphogenetic protein (BMP)-2 and peroxisome proliferators-activated receptor (PPAR) gamma 2 was determined by RT-PCR. Otherwise, MSCs were induced to osteogenic differentiation after microgravity culture, and then the activity of alkaline phosphatase (ALP) was determined by PNPP and the content of osteocalcin (OC) by ELISA. Furthermore, the telomerase activity in MSCs was measured by TRAP. The results showed that simulated microgravity inhibited osteoblastic differentiation and induced adipogenic differentiation accompanied by the change of gene expression of BMP-2 and PPAR gamma 2 in MSCs. Meanwhile, the telomerase activity decreased significantly in MSCs under simulated microgravity. The reduced bone formation in space flight may partly be due to the altered potential differentiation of MSCs associated with telomerase activity which plays a key role in regulating the lifespan of cell proliferation and differentiation. Therefore. telomerase activation/replacement may act as a potential countermeasure for microgravity-induced bone loss. (C) 2008 Elsevier Ltd. All rights reserved.

Related URLs:
<Go to ISI>://WOS:000259409100033

Proliferation of Rat Mesenchymal Stem Cells in Collagen Sponges Reinforced with Poly(Ethylene Terephthalate) Fibers by Stirring Culture Method

by on 9 June 2015in Biology & Biotechnology No comment

The objective of this study is to investigate the effect of medium stirring conditions on the proliferation of rat mesenchymal stem cells (MSC) in collagen sponges reinforced by the incorporation of poly(ethylene terephthalate) (PET) fibers. A collagen solution with PET fibers homogeneously dispersed was freeze-dried, followed by dehydrothermal cross-linking to obtain a collagen sponge incorporating PET fibers. MSC were proliferated in the sponge by a stirring culture method. The PET fibers reinforcement significantly suppressed the sponge deformation in culture. The MSC proliferation was enhanced by the stirring culture to a significantly higher extent than that of a static one. Homogeneous distribution of cells proliferated was observed at the stirring rate of 50 rpm and compared with that at lower and higher rates. Combination of the PET fiber-reinforced sponge with the stirring culture method is a promising way to allow cells to homogeneously proliferate in the sponge. (C) Koninklijke Brill NV, Leiden, 2011

Related URLs:
<Go to ISI>://WOS:000308105900008

Ex Vivo Expansion of Human Umbilical Cord Blood Hematopoietic Stem/Progenitor Cells with Support of Microencapsulated Rabbit Mesenchymal Stem Cells in a Rotating Bioreactor

by on 9 June 2015in Biology & Biotechnology No comment

Expansion of human umbilical cord blood mononuclear cells (MNCs) was carried out with/without the support of alginate-chitosan-alginate (ACA) microcapsules containing rabbit bone marrow (rBM) mesenchymal stem cells (MSCs). Cells were cultured in a rotating wall vessel (RWV) bioreactor and also in tissue-culture plates using serum-free media supplemented with conventional doses of purified human recombinant cytokines for 7 days. The total nucleated cell density, pH and osmolality of the culture media in both co-culture systems were measured every 24 hours. Flow cytometry analysis of the CD34(+) population and methylcellulose colony assays for assessing the pluripotency of the population were carried out after Oh, 72h and 168h of culture. The RWV bioreactor co-culture, combined with a cell-dilution feeding protocol, was observed to be efficient in expanding UCB MNCs. By the end of 168h of culture using this system, the total nucleated cell number had grown around 107-fold, whilst the CD34(+) cells 26-fold and colony-forming units in culture 19-fold. Within RWV alone control and static co-culture control groups, however, expansions of total nucleated cell number were 52-fold and 10-fold, respectively, while CD34(+) cells and CFU-Cs numbers both changed mildly (p < 0.01, compared with RWV co-culture group). It was thus demonstrated that the expansion of HSCs can be achieved at a large-scale with the support of microencapsulated stromal cells using this bioreactor.

Related URLs:
<Go to ISI>://WOS:000291289600009

Ex vivo expansion of human umbilical cord blood hematopoietic stem/progenitor with support of microencapsulated rabbit mesenchymal stem cells in rotating wall vessel

by on 9 June 2015in Biology & Biotechnology No comment

Expansion of human umbilical cord blood mononuclear cells (MNCs) was carried out with/without the support of alginate-chitosan-alginate (ACA) microcapsules containing rabbit bone marrow (rBM) mesenchymal stem cells (MSCs). Cells were cultured in a rotating wall vessel (RWV) bioreactor and also in tissue-culture plates using serum-free media supplemented with conventional doses of purified human recombinant cytokines for 7 days. The total nucleated cell density, pH and osmolality of the culture media in both co-culture systems were measured every 24 hours. Flow cytometry analysis of the CD34+ population and methylcellulose colony assays for assessing the pluripotency of the population were carried out after 0h, 72h and 168h of culture. The RWV bioreactor co-culture, combined with a cell-dilution feeding protocol, was observed to be efficient in expanding UCB MNCs. By the end of 168h of culture using this system, the total nucleated cell number had grown around 107-fold, whilst the CD34+ cells 26-fold and colony-forming units in culture 19-fold. Within RWV alone control and static co-culture control groups, however, expansions of total nucleated cell number were 52-fold and 10-fold, respectively, while CD34+ cells and CFU-Cs numbers both changed mildly (p < 0.01, compared with RWV co-culture group). It was thus demonstrated that the expansion of HSCs can be achieved at a large-scale with the support of microencapsulated stromal cells using this bioreactor.

Related URLs:
<Go to ISI>://WOS:000248035500193

From spindle to spherical: Is spherical shape a potential predictor of human mesenchymal stem cells with increased differentiation capability?

by on 9 June 2015in Biology & Biotechnology No comment

Because human mesenchymal stem cells (hMSCs) can proliferate indefinitely in an undifferentiated state and differentiate into various cell types, hMSCs are expected to be useful for cell replacement therapy. But the clinic application is limited by its differentiation efficiency of hMSCs. It has been proved that cells can be geometrically switched between gene programs for growth, apoptosis and differentiation. Previous studies showed that hMSCs started showing round when exposed to modeled microgravity (MMG), while their differentiation capability seemed enhanced simultaneously. Thus, this article briefly reviews such studies, and hypothesizes that “spherical shape” could be a potential predictor of hMSCs with potentiated differentiation capability.

Related URLs:
http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=emed9&AN=2009536202
http://sfxhosted.exlibrisgroup.com/mayo?sid=OVID:embase&id=pmid:&id=doi:10.1016%2Fj.bihy.2009.06.004&issn=1756-2392&isbn=&volume=2&issue=6&spage=407&pages=407-409&date=2009&title=Bioscience+Hypotheses&atitle=From+spindle+to+spherical%3A+Is+spherical+shape+a+potential+predictor+of+human+mesenchymal+stem+cells+with+increased+differentiation+capability%3F&aulast=Li&pid=%3Cauthor%3ELi+J.%3C%2Fauthor%3E&%3CAN%3E2009536202%3C%2FAN%3E

In vitro osteogenic differentiation of rat mesenchymal stem cells in a microgravity bioreactor

by on 9 June 2015in Biology & Biotechnology No comment

Mesenchymal stem cells (MSCs) are multipotent progenitor cells with the ability to differentiate into osteoblasts, chondroblasts, myocytes, and adipocytes. They have potential for bone tissue engineering by the utilization of in vitro expanded cells with osteogenic capacity and their delivery to the appropriate sites via biomaterial scaffolds. The objective was to evaluate the potential of rat bone marrow MSCs to form 3D bone-like tissue by the use of mineralized poly(DL-lactic-co-glycolic acid) (PLGA) foam and osteoinductive medium under rotating culture conditions. PLGA foams were prepared by solvent casting and particulate leaching, then mineralized by incubating in simulated body fluid. MSCs isolated from the bone marrow of young Wistar rats were expanded and seeded on the mineralized scaffolds. The cell-polymer constructs were then cultured in a slow turning lateral vessel-type rotating bioreactor for 4 weeks under the effect of osteogenic inducers, b-glycerophosphate, ascorbic acid and dexamethasone. Mineralization was evaluated using FT-IR and increases in dry mass; morphology changes of the mineralized foams and cell adhesion was characterized by SEM; cell viability was monitored by MTT (3-(4,5-dimethylthia-zol-2-yl-2,5-diphenyl tetrazolium bromide). Osteogenic differentiation was determined by using immunohistochemistry (anti-Osteopontin). Results indicate the feasibility of bone tissue engineering with MSCs and mineralized PLGA scaffolds supporting cell adhesion, viability and osteogenic differentiation properties of cells in hybrid structures under appropriate bioreactor conditions.

Related URLs:
http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=emed8&AN=2008202967
http://sfxhosted.exlibrisgroup.com/mayo?sid=OVID:embase&id=pmid:&id=doi:10.1177%2F0883911508091828&issn=0883-9115&isbn=&volume=23&issue=3&spage=244&pages=244-261&date=2008&title=Journal+of+Bioactive+and+Compatible+Polymers&atitle=In+vitro+osteogenic+differentiation+of+rat+mesenchymal+stem+cells+in+a+microgravity+bioreactor&aulast=Koc&pid=%3Cauthor%3EKoc+A.%3C%2Fauthor%3E&%3CAN%3E2008202967%3C%2FAN%3E

Cytoskeletal proteins and stem cell markers gene expression in human bone marrow mesenchymal stromal cells after different periods of simulated microgravity

by on 9 June 2015in Biology & Biotechnology No comment

Mesenchymal stem (stromal) cells (MSCs) are present in a variety of tissues during prenatal and postnatal human development. In adult organism, they are prevalent in bone marrow and supposed to be involved in space-flight induced osteopenia. We studied expression of various genes in human bone marrow MSCs after different terms of simulated microgravity (SMG) provided by Random Positioning Machine. Simulated microgravity induced transient changes in expression level of genes associated with actin cytoskeleton, especially after 48 h of SMG. However, after 120 h exposure in SMG partial restoration of gene expression levels (relative to the control) was found. Similar results were obtained with bmMSCs subjected to 24 h readaptation in static state after 24 h in SMG. Analysis of 84 genes related to identification, growth and differentiation of stem cells revealed that expression of nine genes was changed slightly after 48 h in SMG. More pronounced changes in gene expression of "stem cells markers" were observed after 120 h of simulated microgravity. Among 84 investigated genes, 30 were up-regulated and 24 were down-regulated. Finally, MSCs osteogenesis induced by long-term (10-20 days) simulation of microgravity was accompanied by down-regulation of gene expression of the main osteogenic differentiation markers (ALPL, OMD) and master transcription osteogenic factor of MSCs (Runx2). Thus, our study demonstrated that changes in expression level of some genes associated with actin cytoskeleton and stem cell markers are supposed to be one of the mechanisms, which contribute to precursor's cellular adaptation to the microgravity conditions. These results can clarify genomic mechanisms through which SMG reduces osteogenic differentiation of bmMSCs. (C) 2011 Elsevier Ltd. All rights reserved.

Related URLs:
<Go to ISI>://WOS:000298622700004