Effect of Substrate Topography and Chemistry on Human Mesenchymal Stem Cell Markers: A Transcriptome Study

BACKGROUND AND OBJECTIVES: The International Society for Cellular Therapy (ISCT) proposed a set of minimal markers for identifying human mesenchymal stromal cells (hMSCs) in 2007. Since then, with the growing interest of better characterising hMSCs, various additional surface markers have been proposed. However, the impact of how culture conditions, in particular, the culture surface, vary the expression of hMSC markers was overlooked. METHODS AND RESULTS: In this study, we utilized the RNA sequencing data on hMSCs cultured on different surfaces to investigate the variation of the proposed hMSC biomarkers. One of the three ISCT proposed positive biomarker, CD90 was found to be significantly down regulated on hMSCs culture on fibrous surfaces when compared to flat surfaces. The detected gene expression values for 177 hMSCs biomarkers compiled from the literature are reported here. Correlation and cluster analysis revealed the existence of different biomarker communities that displayed a similar expression profile. We found a list of hMSCs biomarkers which are the least sensitive to a change in surface properties and another list of biomarkers which are found to have high sensitivity to a change in surface properties. CONCLUSIONS: This study demonstrated that substrate properties have paramount effect on altering the expressions of hMSCs biomarkers and the proposed list of substrate-stable and substrate-sensitive biomarkers would better assist in the population characterisation. However, proteomic level analysis would be essential to confirm the observations noted.

Advances in efficacy and security of expanded mesenchymal stem cells in vitro / 生物工程学报

The multipotent differentiation and immunosuppression capability of mesenchymal stem cells (MSCs) make it attractive source for stem cell therapy to treat serious diseases, including neural system diseases and immune disorders. For large scale clinical applications, MSCs have to be expanded to produce sufficient quantity for multiple treatments. While conventional passaging is not appropriate for such a task, bioreactor can be used to expand MSCs more efficiently. Yet the efficacy and biosafety of expanded MSCs must be properly assessed before the expanded MSCs can be implanted. This review presented state-of-the-art in expanding MSCs focusing on the progress on the assessment of the efficacy and biosafety of in vitro expanded MSCs. Current obstacles were discussed and future research directions were outlined.

Construction of pIRES2-AcGFP1-CD eukaryotic expression plasmid and its expression in bone marrow mesenchymal stem cells / 中国组织工程研究

BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) are easily isolated and amplified, and facilitate the exogenous gene transfer and expression. In the human medicine, it is believed that BMSCs are ideal therapeutic cells and target cells in the gene therapy.OBJECTIVE: To investigate liposome-mediated cytosine deaminase (CD) gene transfecting rabbit BMSCs and its gene expression. DESIGN: A single sample observation. SETTING: Dalian Research and Development Center for Stem Cell and Tissue Engineering; Department of Biochemistry, College of Basic Medical Science, Dalian Medical University.MATERIALS: This study was performed at in the Dalian Research and Development Center for Stem Cell and Tissue Engineering; Department of Biochemistry, College of Basic Medical Science, Dalian Medical University from March 2006 to June 2007. New Zealand big-ear white rabbits of either gender, weighing 2.0-2.5 kg, with the age of 5 months old, were included in this study. METHODS: The CD gene was obtained from E.coli JM109 DNA by polymerase chain reaction (PCR). The fragment was cloned into pMD19-T vector. After restriction enzyme BamHI/XhoI digestion analysis and DNA sequence analysis, pIRES2-AcGFP1-CD eukaryotic expression plasmid was constructed. Meanwhile, BMSCs were harvested, cultured and identified. After enzyme digestion of eukaryotic expression plasmid, the rabbit BMSCs were transfected by Lipofectamine 2000-mediated method. Twenty-four hours after transfection, expression of green fluorescent protein was observed under an inverted fluorescent microscope. MAIN OUTCOME MEASURES: Construction of eukaryotic expression plasmid and identification of CD gene-transferred BMSCs. RESULTS: CD gene was cloned and connected to eukaryotic expression plasmid with green fluorescence. Twenty-four hours after transfecting rabbit BMSCs, it was found under an inverted microscope that under the excitation of 488 nm blue light, green fluorescence appeared in the pIRES2-AcGFP1-CD and pIRES2-AcGFP1 empty-plasmid transfected BMSCs, but not in the non-transfected ones. It indicates that CD gene successfully transferred BMSCs. CONCLUSION: BMSCs are ideal vectors in the CD gene therapy.

Simulation of the growth of neurosphere cultured in bioreactors / 生物医学工程学杂志

When the size of a neurosphere cultured in vitro reaches a certain critical value, a necrotic core will appear inside the neurosphere because of the limitation of oxygen or other nutrients transport from medium to the cells in the neurasphere. Large necrotic core will greatly reduce the expansion of NSCs. The cellular automaton (CA) model is applied in this article to model the growth of NSCs in sphere state. The appearance and enlargement of the necrotic core in a neurosphere is calculated by coupling the CA model with the nutrient diffusion analysis in bioreactors. The calculation results indicate that the culture conditions, such as seeding density, the concentration of nutrients in medium and the mass transfer coefficient between a neurosphere and medium, have some effects on the appearance of the necrotic core. However, the necrotic core mainly depends on the inner diffusion. It will certainly appear if the size of the neurosphere is large enough even the outside mass transfer is in a good condition in bioreactors. Additionally, the appearance of the necrotic core resulting from the shortage of oxygen is earlier than that caused by the limitation of glucose. And the growth of the necrotic core is very fast after its appearance, and the whole neurosphere may become necrotic. The model developed with cellular automaton and mass transfer is a good qualitative representation of NSCs growth in bioreactors.

Study on cryopreservation of cells and tissues / 医疗卫生装备

Cryopreservation of bovine articular cartilage and Human Bone Marrow Fibroblast (HBMF) monolayer cells is studied in the paper. The results show that the high concentrations of Cryoprotective agents (CPA) coupled with the appearance of sucrose and high contents of 1,2-propanediol contribute to reducing the formation and growth of ice nuclei and have the potential to obtain good protective effects. High concentrations of CPA can result in great damages to cartilage and HBMF monolayer cells, which can be moderated by decreasing the temperature of adding and removal of CPA. In the frozen cartilage, which is put into liquid nitrogen without adding of any CPA, the architectures of both the chondrocytes and extracellular matrix have been severely damaged. While in the control group, the chondrocytes are intact and well preserved.