IMT504, the prototype of the immunostimulatory oligonucleotides of the PyNTTTTGT class, is a potent signal for mesenchymal stem cells expansion in-vitro and in-vivo with potencial use as a medicine in tissue repair therapy.

MONTANER AD.; HERNANDO INSÚA A.; RODRÍGUEZ JM.; ELÍAS F.; FLÓ J.; HOFER EL,; LÓPEZ RA.; CHASSEING NA.; ZORZOPULOS J.

Boston ,MA, USA.

Workshop; Cambridge Healthtech Institute´s Second Annual . Back to the Science of Stem Cell Research.; 2006

Cambridge Healthtech Institute

Bone marrow-derived Mesenchymal Stem Cells (MSCs) have the capacity to differentiate in vitro into osteocytes, chondrocytes, adipocytes, myocytes, hepatocytes, endothelial cells and neurons. This capacity makes them a likely cellular source for clinical application in tissue repair therapies. Preclinical studies performed in different animal models of tissue damage have given support to this hypothesis. We have now found that IMT504, the prototype of the PyNTTTTGT class of immunostimulatory oligonucleotides, is a potent stimulatory signal for MSC expansion both in vitro and in vivo which accelerates reparation of an experimental defect in the tibia of rats when subcutaneously injected. First (in vitro), bone marrow cells (BMC) were obtained from rat femurs and seeded in plastic culture flasks for cultivation in alpha medium plus 20% fetal bovine serum in either the presence or the absence of IMT504 (1 ìM). The cloning capacity of MSCs was evaluated through the colony forming unit-fibroblast (CFU-F) assay. Each CFU-F is derived from a single precursor cell or MSC. Clones of >50 cells were scored as CFU-F after 14 days of culture. We found that incubation in the presence of IMT504 increased about three times the mean number of CFU-F. Second (in vivo), we evaluated the cloning capacity of MSC from BM in a group of rats subcutaneously injected with IMT504 or saline solution. We found that bone marrow culture of rats inoculated with IMT504 had a significantly higher number of CFU-F as compared with rats inoculated with saline solution. Furthermore, the number of CFU-F in circulation was about six times higher in rats treated with IMT504 as compared with controls injected with saline solution. Finally, MSCs proliferated in vitro or in vivo under IMT504 stimulation conserved its capacity to differentiate into multiple cell lineages (adipocytes, fibroblasts and osteocytes). Third (systemic), we found that an experimental defect introduced in the tibia of rats was more rapidly repaired in animals subcutaneously injected with IMT504 than in animals injected with saline solution. These results clearly show the potential of IMT504 to act as a medicine in tissue repair therapy. Regarding this, it should be pointed out that in preclinical trials we have previously demonstrated that IMT504 is a very safe drug.