Biological Sensing of Nitric Oxide in Macrophages and Atherosclerosis Using a Ruthenium-Based Sensor

Area of Science:

• Biomedical Engineering
• Chemical Biology
• Cardiovascular Research

Background:

• Nitric oxide (NO) from macrophages is crucial in atherosclerosis and a potential biomarker.
• Developing reliable sensors for NO detection in cardiovascular disease is essential.

Purpose of the Study:

• To evaluate a ruthenium-based fluorescent NO sensor (Ru-NO) for its uptake, distribution, and NO detection capabilities.
• To assess Ru-NO's utility in macrophages, plasma, and atherosclerotic plaques for atherosclerosis assessment.

Main Methods:

• In vitro and in vivo studies using human cell lines (THP1) and Apoe−/− mice.
• Assessed Ru-NO uptake and fluorescence via mass cytometry, confocal microscopy, and flow cytometry.
• Analyzed Ru-NO fluorescence in murine and human plasma samples, correlating with diet and disease state.

Main Results:

• Ru-NO was robustly taken up by macrophages in vitro and in vivo, with higher uptake in activated macrophages.
• Ru-NO fluorescence co-localized with macrophages in atherosclerotic plaques of Apoe−/− mice.
• Increased Ru-NO plasma fluorescence was observed in high-cholesterol diet-fed mice and decreased fluorescence in human myocardial infarction patients.

Conclusions:

• Ru-NO is efficiently internalized by macrophages and detectable in atherosclerotic lesions.
• Ru-NO fluorescence in plasma correlates with atherosclerosis progression in mice and disease severity in humans.
• Ru-NO demonstrates significant potential as a diagnostic sensor for atherosclerosis.