Modares Journal of Biotechnology

Abstract Stem cells are characterized by their capacity for self-renewal and their ability to differentiate into specific cell types under the influence of their microenvironment. It is known that matrix chemistry controls stem cell differentiation. Single cell encapsulations of the Mesenchymal stem cells into a semi-permeable microgel, allows a greater control of the stem cell fate. In this study, a chip for single-cell encapsulation was designed and fabricated using microfluidic technology. By using microfluidic chip, human bone marrow mesenchymal stem cells (hBMSCs) are encapsulated inside alginate and alginate-poly-l lysine (PLL) microgels. The results of long-term viability of MSCs inside alginate-PLL microgels, shows a significant increase compared to alginate microgels. Mesenchymal stem cell proliferation in alginate-PLL microgels also increased significantly on days 14 and 21. It seems that PLL improves cell adhesion and function by creating a positively charged matrix. Microscopic studies indicate that the morphology of the cells inside the microgels is spherical. However, the average diameter and volume of cells in microgels containing PLL are smaller than others, which indicates more proliferation and space limitation inside the microgels. Therefore, single cell alginate-PLL microgels provide a suitable substrate in clinical studies for tissue engineering, organ transplantation and cell therapy.

Abstract Aims: Nitric oxide (NO) plays an important role in maintaining cellular stem status, and the range of electromagnetic fields (EMF) is very deep in contrast to the electric field. The aim of this study was to investigate the effect of electromagnetic field and nitric oxide on the neural differentiation proteins marker and viability of the rat bone marrow mesenchymal stem cells.
Materials and Methods: The present experimental research was conducted on bone marrow mesenchymal stem cells of Vistar rats. For treatments of the cells, high (1mM) and low (10micromolar Deta-NO) concentrations were used as a nitric oxide donor molecule and 50Hz low-frequency electromagnetic field and they were compare with the control group. The cell viability was recorded by MTT assay test, the neural differentiation pathway gene expression was investigated by RT-PCR technique, and the neural differentiation marker protein expression was evaluated by Immunocytochemistry technique. The data were analyzed by one-way ANOVA, using SPSS 13 software.
Findings: After 24 hours of treatment with nitric oxide and EMF, the rate of viability in all groups was significantly decreased compared to the control group. After 48 hours, EMF alone, as well as with low concentration of nitric oxide did not decrease the rate of viability and cell growth increased compared to the control group. In the group treated with high nitric oxide concentration along with EMF, MAP2 protein was expressed in the number of cells more than the control group and the one treated with EMF.
Conclusion: The electromagnetic field, along with its high concentration of nitric oxide, decreases the number of rat bone marrow mesenchymal stem cells and, by increasing cell size, gene expression and neural differentiation proteins marker facilitates their differentiation to nerve-like cells.

Abstract Most patients with liver diseases are in the waiting list of liver implantation for a long period of time because of the lack of enough donors. Liver differentiation potential of Mesenchymal Stem Cells (MSCs) is a new perspective in curing these patients. Tissue engineering improves hepatocyte differentiation by coating the culture surfaces with Glycosaminoglycans (GAGs) such as Heparan Sulfate (HS). Cell detachment and death during hepatogenic differentiation hamper the efficiency of cell therapy. This study aims to establish a matrix. mimicking the liver extracellular matrix, which supports the attachment and proliferation potential of MSCs, as well. Collagen was physically coated on polystyrene plates. Collagen-GAG matrix was constructed by covalently immoblizing the HS molecules on collagen by EDC. Cell attachment and proliferation were evaluated by direct cell-counting and MTT methods. GAG presence on collagen was verified by Safranin O staining. Comparisons showed that the highest attachment belonged to collagen, collagen-HS and polystyrene, respectively. Collagen matrix showed also the highest cell proliferation. Collagen-GAG provided more suitable matrix for cell proliferation compared to polystyrene. The results further showed that biomimicked collagen-GAG matrix supports superior attachment and viability for MSCs compared to polystyrene.

Abstract Stem cell therapy has been introduced as an innovative and promising treatment in Ischemic diseases. Mesenchymal stem cells are considered for cell therapy to some extent due to their immunemodulatory, differentiation potential, feasibility of isolation and proliferation properties. Stem cells, after transplantation, often encounter harsh and hypoxic environment in ischemic tissues, which leads to cell death and decreased therapeutic efficiency. On the other hand, the fate of stem cell viability and differentiation is still an ambiguous issue in cell therapy regenerative medicine. To overcome this problem, Hypoxic/Ischemic preconditioning has been reported as a powerful tool with beneficial effects on cell survival. The reported master regulator in this process is a transcription factor known as HIF-1α. This study aimed to over-express HIF-1α in mesenchymal stem cells along with eGFP by using lenti viral vectors. Bisistronic expression of eGFP and HIF-1α provides the possibilities of tracking the transplanted cells and mimicking the hypoxic conditions for genetically modified stem cells for future animal model studies.