Estudio de la migración de precursores mesenqulmales. Estrategia para la mejora de sus propiedades migratorias

Abstract

ABSTRACT: Mesenchymal stem cells (MSCs) have promising properties for applicalions in cell therapy. They are capable of migrating, differenliating, and secreting soluble factors, and they also have immunomodulatory effects and are considered "hypoimmunogenic". The combination ofthese properties makes them good candidates for the treatment of a wide range of diseases. Despite great advances in the field and their use in clinical trials, much information about the biology of these MSCs is slill lacking. For the success of MSC therapy, the cells mus! reach the damaged !argel tissue and engraft, to accomplish their reparative function. However, the effecliveness of the delivery of the cells to !argel organs, and their permanence, remains a major challenge. With !he intenlion of developing a richer understanding of the migratory capacity of mesenchymal precursors (MPs), we obtained cells from different lissues and tested their migration in vitro. The results showed that MPs spontaneously develop dynamic blebs in culture. When the cells were unattached and had a rounded shape, blebs were generalized around the plasma membrane . By contras!, when the cells adhered, they acquired an elongated shape, and bleb structures became polarized on the leading edge of the cells in combinalion with lamellipodia. We found that blebs were rich in F-aclin, RhoA and ERM proteins (ezrin, radixin and moesin; crosslink actin filaments with plasma membrane). Blebs were affected by adhesion to the substrate and their formalion was inhibited by the addition of blebbistatin. Migration assays showed a correlalion between the migration capacity of MPs and the number of blebs they developed. Moreover, migration decreased significantly when blebbistalin was added. The application of therapeulic ultrasound (US) al low intensilies has been proposed as a strategy to improve the migralion capacity of MPs. The stimulation of the cells with US did not affect their viability or proliferation capacity. Furthermore, there were no changes in morphology or cell groupings and no detectable changes al the cytoskeleton level. The ability of the cells to migrate and invade also remained constan! despite the US treatment. Finally, no variations in !he level of gene expression, of genes previously involved in stimulation with US, were detected for ROCK1, integrin 131, laminin 131, type I collagen and transforming growth factor 131. Considering !he results as a whole, il would be interesling to continue studying the role of the blebs in 30 cultures and also in in vivo migralion, as well as to investigate the potential application of US using variations of the tested parameters.