RESUMEN
Healing of skeletal defects is strictly dependent on osteogenesis and efficient vascularization of engineered scaffolds. Insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF) are both involved in these processes. The in vitro administration of IGF-1 in association with VEGF is able to modulate the osteoblastic or endothelial commitment of mesenchymal stromal cells (MSCs) of different origins (e.g. periosteum and skin). In the present study, in order to deepen a possible paracrine effect of IGF-1 and VEGF on periosteum-derived progenitor cells (PDPCs) and skin-derived MSCs (S-MSCs), a Transwell coculture approach was used. We explored the genes involved in endothelial and osteoblastic differentiation, those modulating mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3'-kinase (PI3K)-AKT signaling pathways as well as genes implicated in stemness (i.e. Sox2, Oct4, and Nanog). Periosteal cells, which are typically committed toward osteoblastogenesis, are driven in the direction of endothelial gene expression when influenced by S-MSCs. The latter, once influenced by PDPCs, lose their endothelial commitment and increase the expression of osteoblast-associated genes. PI3K/AKT and MAPK signaling pathways seem to be markedly involved in this behavior. Our results evidence that paracrine signals between MSCs may differently modulate their commitment in a bone microenvironment, opening stimulating viewpoints for skeletal tissue engineering strategies coupling angiogenesis and osteogenesis processes.
Asunto(s)
Linaje de la Célula/efectos de los fármacos , Factor I del Crecimiento Similar a la Insulina/farmacología , Células Madre Mesenquimatosas/citología , Comunicación Paracrina/efectos de los fármacos , Factor A de Crecimiento Endotelial Vascular/farmacología , Adulto , Técnicas de Cocultivo , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Inmunofenotipificación , Masculino , Células Madre Mesenquimatosas/efectos de los fármacos , Células Madre Mesenquimatosas/metabolismo , Persona de Mediana Edad , Células Madre Multipotentes/citología , Células Madre Multipotentes/efectos de los fármacos , Células Madre Multipotentes/metabolismo , Periostio/citología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas Recombinantes/farmacología , Piel/citologíaRESUMEN
There is a great deal of interest in the understanding of possible age-related changes in Mesenchymal Stem Cells in view of their use for regenerative medicine applications. Given to the outmost standing of periosteum in bone biology and to probe data for a cell-based therapy promoting graft osseointegration in the elderly, we tried to identify specific aging markers or pattern of expression in human periosteal precursor cells. Immunohistochemical detection of Ki67 and p53, Nitric Oxide production and qRT- PCR of a selected gene panel for osteoblastic differentiation, bone remodeling and stemness were evaluated. We confirmed that both Ki67 and p53 are noteworthy indicators of senescence in human periosteal precursor cells and their expression significantly correlate with cell NO production. Moreover, cell age affects genes involved in bone remodeling, with a significant increase in interleukin-6 mRNA expression and receptor activator of nuclear factor kappa-B ligand/osteoprotegerin ratio. The analysis of mRNAs of genes involved in pluripotency regulation and self-renewal of stem cells, evidenced changes at least in part related to bone remodeling. We believe that this is the first study taking on age-related changes in human periosteal precursor cells, and paving the way toward new regenerative medicine strategies in bone aging and/or bone metabolic diseases.