Functional rejuvenation of endothelial cell aging by transient reprogramming.

Senescent endothelial cells (ECs), characterized by a reduced angiogenic and regenerative potential, are key players in the pathophysiology of cardiovascular diseases. Therefore, targeting these cells has been suggested as an effective therapeutic strategy to increase health. Here, we are the first to report that non-genetic overexpression of the Yamanaka factors induces partial functional rejuvenation and attenuation of senescence-associated features in endothelial cells. Methods to characterize the effects of the transient reprogramming included quantification of gene expression as well as measurements of cellular functions in vitro. Further, in vivo experiments were performed in a hind-limb ischemia model. The application of the pharmacological cocktail to replicative senescent ECs resulted in a robust but timely restricted activation of Oct3/4, Sox2, Klf4, and c-Myc (p < 0.0 and p < 0.01). This was associated with a significant reduction of senescence markers such as p16ink4a and p14arf (p < 0.01). Additionally, qPCR-based telomere length measurements were stabilized, and functional properties of senescent ECs, such as proliferation, migration, sprouting, and tube formation, were improved (p < 0.05). Continuous cultivation of the treated cells over the long term indicated that expression of p16ink4a and p14arf remained significantly low, while cell migration remained enhanced. In vivo, a significantly improved blood flow was observed at 7 and 14 days after hind-limb ischemia in 21 months old C57BL/6 mice (p < 0.001). In conclusion, we revealed that a partial attenuation of endothelial cell senescence-associated features can be induced by a short pharmacological overexpression of the Yamanaka factors. While the compounds used are individually approved for other indications, their combined use in this context highlights a conceptual translational potential, whereas the clinical applicability of this approach remains to be evaluated.