Characterization of Umbilical Cord Mesenchymal Stromal Cells Overexpressing Klotho and In Vitro Anti-Aging Efficacy of Their Derived Extracellular Vesicles.

Age-related degeneration remains a premier biomedical challenge, frequently underpinned by cellular senescence and stem cell dysfunction. Accumulating evidence suggests that umbilical cord mesenchymal stromal cell (UC-MSC)-derived extracellular vesicles (UC-EVs) and the longevity protein Klotho hold great promise as anti-aging biotherapeutics. Here, we strategically engineered UC-MSCs to overexpress Klotho and generated functional Klotho-enriched UC-EVs (KL-EVs). Our data demonstrated that genetic modification endowed UC-MSCs with prominent osteogenic differentiation potency and angiogenesis efficacy. More importantly, KL-EVs profoundly rescued multifaceted senescent phenotypes in both adult bone marrow mesenchymal stem cells (BMSCs) and human renal tubular epithelial cells (HK-2) in vitro. In particular, KL-EVs rescued the age-related differentiation bias of adult BMSCs by robustly prompting their osteogenic differentiation capacity. Taken together, we developed a novel type of UC-MSCs and isolated their EVs enriched with Klotho protein. This strategy integrated and enhanced the anti-aging effects of both entities in vitro, offering a new perspective for counteracting cellular senescence and alleviating age-associated degenerative alterations.