Premium
Endothelial overexpression of P25 causes premature vascular aging by promoting SIRT1 protein degradation
Author(s) -
MondacaRuff David,
Konja Daniels,
Singh Sandeep,
Fu Bowen,
Wang Yu
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.05165
Subject(s) - myograph , senescence , phenylephrine , electrical impedance myography , oxidative stress , sirtuin 1 , endothelium , vascular smooth muscle , medicine , vascular tissue , endocrinology , biology , chemistry , microbiology and biotechnology , downregulation and upregulation , biochemistry , vasodilation , botany , smooth muscle , blood pressure , gene
Background P25 is a regulatory subunit of cyclin‐dependent kinase 5 (CDK5). The CDK5/P25 signaling is implicated in the regulation of SIRT1, a mammalian sirtuin with an important participation in aging. Hypothesis: Overexpression of endothelial p25 leads to premature vascular aging by regulating SIRT1 degradation. Aims: The aims of this study were to determine if overexpression of p25 in the vascular endothelium induces vascular aging by causing degradation of SIRT1 and increasing vascular contraction, oxidative stress and vascular senescence. Methods: The present study established a transgenic mouse model (EC‐P25) with selective overexpression of P25 in endothelial cells. Aortas were obtained from 12‐ or 30‐weeks old EC‐p25 mice and control littermates for all experiments. Wire myography was performed in quiescent thoracic aorta with Mulvany‐Halpern wire myograph system to measure isometric tension in the presence or absence of SIRT1 activators or inhibitors. Vascular senescence was evaluated using senescence‐associated β‐galactosidase (SA‐β‐gal) staining in aortae, whereas heamatoxylin‐eosine (H & E) staining was performed on aortic sections to evaluate aortic wall hypertrophy. Melondialdehyde (MDA) concentration in aortic homogenates represented a measure of oxidative stress, and protein expression levels were measured by Western blotting. Results: EC‐P25 mice showed increased vascular tone responsiveness to alpha‐1‐adrenergic receptor agonist phenylephrine (PE) compared to the control littermates suggesting that overexpression of p25 in the vascular endothelium has deleterious effects on vascular function. SA‐β‐gal staining was increased in EC‐P25 mice when compared to the control group, demonstrating vascular senescence. H & E staining also showed aortic wall hypertrophy with an increase in aortic wall thickness in EC‐P25 mice compared to control mice. MDA concentration was also higher in EC‐P25 mice aorta than in the control group, implying increased oxidative stress. SIRT1 protein was found to be fragmented with increased levels of shorter fragments in EC‐P25 aorta when compared to their control littermates, suggesting that, over‐expression of P25 in the vascular endothelium regulates SIRT1 degradation leading to premature aging, adverse remodeling and loss of functional regulation. Conclusion: Overexpression of endothelial p25 may regulate vascular function by increasing vascular tone, aortic wall hypertrophy, oxidative stress and vascular aging leading to vascular disease. Additionally, a fragment of SIRT1 with enhanced deacetylase activity was detected in arteries of EC‐P25 mice, whereas EX‐527, a SIRT1 inhibitor, attenuated endothelium‐dependent contractions. In conclusion, the results suggest that targeting CDK5/P25/SIRT1 signaling represents a promising strategy for ageing‐associated vascular diseases.