Local endothelial DNA repair deficiency causes aging-resembling endothelial-specific dysfunction

Area of Science:

• Vascular Biology
• Genetics
• Aging Research

Background:

• Genomic instability is a known factor in vascular aging.
• Endothelial cells (ECs) play a critical role in vascular health.
• DNA repair mechanisms are essential for maintaining EC function.

Purpose of the Study:

• To investigate the specific vascular aging outcomes resulting from localized endothelial DNA damage.
• To determine the role of ERCC1 DNA repair in endothelial function and vascular aging.

Main Methods:

• Generation of EC-knockout (EC-KO) mice with targeted removal of ERCC1 DNA repair.
• Assessment of microvascular function, including dilation, leakage, and perfusion in various organs (skin, kidney, lung, aorta).
• Measurement of vasodilator responses in isolated arteries and analysis of senescence markers (p21) and superoxide production.

Main Results:

• EC-KO mice exhibited decreased microvascular dilation, increased kidney leakage, reduced lung perfusion, and aortic stiffness.
• DNA damage and p21 expression were localized to the endothelium in EC-KO mice.
• Impaired nitric oxide-mediated vasodilation was observed, alongside increased superoxide production, while endothelium-derived hyperpolarization remained intact.

Conclusions:

• A selective DNA repair defect in ECs leads to age-related endothelial dysfunction.
• The loss of endothelium-derived nitric oxide (NO) is a major contributor to these vascular changes.
• Increased superoxide generation may exacerbate end-organ damage in the kidney and lung.