IMT504 the Prototype of the Immunostimulatory Oligonucleotides of the PyNTTTGT Class Augments the Number of Bone Barrow Derived Adherent Cells with Multipotent Differentiation Capacity In Vitro and In Vivo

HERNANDO INSÚA, A.; MONTANER, A.D.; RODRIGUEZ, J.M.; ELÍAS, F.; FLÓ, J.; LÓPEZ, R.A.; ZORZOPULOS, J.; HOFER E.L.; CHASSEING, N.A.

Buenos Aires

Jornada; VIII Jornadas Multidisciplinarías de la SAB; 2006

Sociedad Argentina de Biología (SAB)

Bone marrow (BM)-derived adult Mesenchymal Stem Cells (MSCs) have the capacity to differentiate in-vitro into different cell lines. This capacity makes them a likely cellular source for clinical application in tissue repair therapies.  Here we report evidence indicating that IMT504, the prototype of the PyNTTTTGT class of immunostimulatory oligonucleotides, significantly augment the # of adherent fibroblast colony forming cells (CFU-F) with multipotent differentiation capacity, which are the most commonly properties to define MSCs. When rat BM cells were cultured in the presence of IMT504, the X±SE # of CFU-Fs increased as compared with untreated controls (2.1±0.7 vs. 0.9±0.3 x102/femur, p=0.04). Furthermore, rats inoculated with IMT504 had a significantly higher # of CFU-F both in BM cells (CFU-F: 1.2±0.3 vs. 0.4±0.2 x102/femur, p=0.04) and peripheral blood cell cultures as compared with untreated animals (0.37±0.14 vs, 0.05±0.04 /ml, p=0.03).  On the other hand, CFU-Fs augmented either in-vitro or in-vivo by IMT504 stimulation possess capacity to differentiate to the osteogenic and adipogenic cell lineages as regular MSCs. Finally, we found that repair of an experimental bone defect was accelerated in rats subcutaneously injected with IMT504 as compared with untreated control animals two weeks after (area with consolidated bone:92.6±10.3 vs. 70.3±6.8 %, p=0.003). Importantly, when human BM cells were cultured in the presence of IMT504, the mean # of CFU-F also significantly increased as compared with untreated controls (CFU-Fs: 2.6 ± 1.2 vs. 1.0± 0.6 x101/106 plated). These results suggest the possibility of clinical use of IMT504 in bone and presumably other tissue repair therapies. Regarding this, it should be pointed out that in preclinical trials IMT504 has demonstrated to be a very safe drug.