Abstract 16442: Reprogramming of p66Shc and JunD Improves Age-Related Dysfunction of Angiogenic Early Outgrowth Cells
Introduction: Early outgrowth cells (EOCs) are important modulators of the vascular repair process, favouring myocardial neovascularization. Impairment of EOCs functionality in human aging is mostly driven by reactive oxygen species (ROS), but the molecular mechanisms remain largely unknown. We previously reported that transcription factor JunD and mitochondrial adaptor p66Shc are critically involved in ROS-induced vascular aging.
Hypothesis: The present study investigates the role of JunD and p66Shc in age-related EOCs dysfunction.
Methods: EOCs were isolated and cultured from peripheral blood mononuclear cells of young (25±3 years; n=7) and old (65±6 years; n=7) healthy volunteers enrolled via the Blood Donation Service of the University Hospital Zürich, Switzerland. Gene silencing of p66Shc was performed with siRNA technology (Microsynth®), while JunD overexpression was obtained with a predesigned vector (Origene®). Scrambled siRNA or empty vector were used as negative controls for p66Shc and JunD, respectively. Three days after transfection young and old EOCs were harvested for measurement of O2- levels by ESR spectroscopy, migration assay and real-time PCR. Written informed consent was obtained from all subjects.
Results: EOCs isolated form old individuals showed increased p66Shc expression and JunD downregulation as compared with young subjects. p66Shc and JunD dysregulation in old EOCs was associated with increased O2- generation, blunted migration, upregulation of the NADPH subunit Nox2 as well as reduced expression of the scavenger enzymes manganese superoxide dismutase (MnSOD) and aldehyde dehydrogenase-2 (ALDH2). Interestingly, either p66Shc knockdown or JunD overexpression significantly suppressed age-related O2- production, improved EOCs migration and restored the balance between oxidant and antioxidant enzymes.
Conclusions: p66Shc and JunD are critically involved in age-dependent EOCs dysfunction by altering their redox state. Modulation of aging and longevity genes may improve the clinical efficacy of stem cell therapy in elderly cardiovascular patients.
- © 2013 by American Heart Association, Inc.