Aβ-Induced Damage Memory in hCMEC/D3 Cells Mediated by Sirtuin-1

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Beta-amyloid (Aβ) accumulation is linked to endothelial dysfunction in Alzheimer's disease (AD).
• Current anti-Aβ therapies show limited efficacy in improving cerebrovascular function in AD models.
• The persistence of Aβ-induced endothelial damage, even after Aβ clearance, is not well understood.

Purpose of the Study:

• To investigate the existence of cerebrovascular endothelial damage memory in human cerebral microvascular endothelial cells (hCMEC/D3).
• To explore the role of sirt-1 and Nicotinamide Adenine Dinucleotide (NAD+) in Aβ-induced endothelial damage memory.
• To develop a kinetics model for understanding the dynamics of Aβ-induced cerebrovascular endothelial damage.

Main Methods:

• hCMEC/D3 cells were exposed to Aβ1-42 for 12 hours, followed by a 12-hour Aβ-free incubation period.
• Cell vitality and sirt-1 levels were assessed post-Aβ exposure.
• The effects of sirt-1 activator (SRT2104), sirt-1 inhibitor (EX527), and NAD+ supplementation were evaluated.
• A mechanism-based kinetics progression model was employed to analyze damage dynamics.

Main Results:

• Endothelial cells exhibited reduced vitality even after Aβ1-42 removal, suggesting cerebrovascular endothelial damage memory.
• Sirt-1 levels normalized post-Aβ removal, but cell vitality remained impaired.
• Sirt-1 activator SRT2104 and NAD+ supplementation dose-dependently ameliorated the damage memory.
• Sirt-1 inhibition exacerbated the damage memory, while NAD+ depletion was critical for its maintenance.

Conclusions:

• Cerebrovascular endothelial damage memory induced by beta-amyloid (Aβ) exists in endothelial cells.
• Sirt-1 is involved in initiating Aβ-induced endothelial damage memory.
• Nicotinamide Adenine Dinucleotide (NAD+) depletion plays a crucial role in maintaining this persistent endothelial damage, offering potential therapeutic targets for Alzheimer's disease.