@misc{,
 copyright={Creative Commons Attribution BY 4.0 license},
 howpublished={online},
 abstract={Regenerative therapy with the use of stem cells in order to restore damaged tissues and organs has been the subject of interest of the medical and scientific community for several years. Recently, mesenchymal stem cells (MSCs) have been very popular among scientists and clinicians. Currently, they are used in experimental and clinical trials of the treatment of central nervous system (CNS) diseases, such as stroke, Alzheimer's, Huntington's, Parkinson's and others, for which there are no effective alternative treatments. In the literature, we can find articles showing that the transplanted MSCs are actively mobilized to damaged tissues, but the mechanism responsible for this process has not been known so far. Moreover, the colonization of damaged tissue areas by systemically administered cells is much less efficient in the case of MSCs than in the case of leukocytes, which may be caused by the lack of expression of receptors and adhesive proteins essential for this process. Increase of the expression of proteins responsible for adhesion and migration may have a positive impact on the transfer of transplanted cells from the vascular bed and their mobilization to the lesion area. The aim of my study was to verify the hypothesis whether increase of VLA-4 integrin expression in MSCs would allow for the enhancement of their adhesive and transmigration properties after systemic transplantation in rat model of brain damage. MSCs with VLA-4 overexpression were obtained by genetic modification with ITGA4 mRNA. The results of the research revealed that transfection with above mentioned construct causes the cells to express the α4 subunit of the VLA-4 integrin, which is not present in native MSCs. Next, the assessment of the movement pattern and adhesion ability of the modified MSCs was performed by applying a microfluidic technique adapted to our purpose, which was used as a model of cell flow through capillary blood vessels. This study showed that during cell flow through the microfluid device both native and modified ITGA4 MSCs mRNA undergo rolling and crawling processes analogous to the steps observed during leukocyte diapedesis. It also revealed that MSCs modified with ITGA4 mRNA were characterized by increased adhesive activity, resulting in an elevated number of cells that stopped while flowing through the chamber. The increase in the adherence rate of cells transfected with ITGA4 mRNA was confirmed in studies with the use of two-chamber transwell culture plates. Subsequently, MSCs characterized by increased expression of the α4 subunit of VLA-4 integrin or native cells were transplanted intra-arterially into the internal carotid artery to rats with striatal damage performed 48 hours earlier. The results of the MRI analysis showed that the MSCs were flowing into the damaged right hemisphere. Moreover, more VLA-4 overexpressing MSCs as compared to the non-genetically modified native cells were seen in the lesion area. Immunohistochemical tests confirmed the results obtained in MRI. They also showed that the transplanted MSCs remained within the brain's blood vessels. 72 hours after transplantation, some cells were visible in the perivascular space. These studies showed that the transfection of human bone marrow mesenchymal stem cells with ITGA4 mRNA induces the expression of the α4 subunit of the VLA-4 integrin, increasing the adhesion ability of the modified cells both in vitro and in vivo. After cell transplantation, the increased expression of the VLA-4 receptor on the surface of MSCs results in the effective accumulation of the transplanted cells in the brain's blood vessels near the lesion, so induction of overexpression of α4 integrin may be used in the future as a potential strategy to increase the colonization of damaged brain areas by systemically administered cells stem.},
 type={Text},
 URL={http://www.rcin.org.pl/Content/151108/PDF/Anna%20Andrzejewska.pdf},
 keywords={Stem Cells},
}