Abstract 14587: Dysregulation of Vascular Autophagy by Overexpression of p25/CDK5 is Associated With Vascular Senescence

Abstract

Introduction: Cardiovascular diseases are the main causes of death worldwide. These diseases are often associated with cardiovascular aging. Autophagy is a degradative cellular process that has been implicated in aging regulation. Cyclin-dependent kinase 5 (CDK5), which is normally activated by its regulatory subunit p25, has been implicated in several diseases. However, the role of p25/CDK5 signaling pathway in cardiovascular diseases and autophagy have not been fully understood. Hypothesis: Upregulation of vascular p25/CDK5 signaling pathway modifies autophagy induction and participates in vascular senescence. Methods: Selective overexpression of p25 (CDK5 activator) in the vascular endothelium was generated in a transgenic mouse model (EC-p25). Then, aortas from 30-weeks old EC-p25 and control mice were collected. Vascular senescence was evaluated with senescence-associated β-galactosidase (SA-β-gal) staining. Protein levels were measured by Western blotting. Primary porcine aortic endothelial cells (PAECs) were transfected with pcDNA, p25 and CDK5. Autophagy activity, autophagic flux, cell death, and senescence were evaluated. A p-value of p<0.05 was considered as statistically significant. Results: EC-p25 mice exhibited increased SA-β-gal staining compared to the Control mice suggesting accelerated aging in the aorta. EC-p25 mice showed increased levels of autophagy compared to the Control mice. On the other hand, overexpression of CDK5 increased cell death, endothelial senescence, autophagy and proteins involved in autophagy induction in PAECs. Conclusion: Accelerated premature vascular aging induced by selective overexpression of the p25/CDK5 signaling pathway in the vascular endothelium may be associated with increased vascular senescence in the aorta by modifying autophagy activity and induction process.