Novel Fluorescent Probes Illuminate Cholesterol Dynamics in Live Cells

The search for solutions to Alzheimer’s disease and other neurodegenerative disorders remains a critical priority in brain research. Maciej J. Stawikowski, Ph.D., an Assistant Professor of Chemistry and Biochemistry at Florida Atlantic University’s Charles E. Schmidt College of Science, believes that understanding how lipids such as cholesterol move through cells and influence communication could hold the key.

The Lipid Connection to Alzheimer’s

“It is well known that lipids and Alzheimer’s are linked. Lipid imbalance may lead to amyloid plaque formation—oversized protein clumps that disrupt cell function, a hallmark of Alzheimer’s,” explains Dr. Stawikowski, who is also a member of the FAU Stiles-Nicholson Brain Institute.

Stawikowski’s team is focused on developing advanced tools to study the relationship between lipids and cellular function. Collaborating with Dr. Qi Zhang, an Associate Professor in FAU’s Department of Chemistry and Biochemistry, the group has designed fluorescent cholesterol probes (CNDs) to investigate cholesterol dynamics in cellular membranes.

Why Cholesterol Matters

Cholesterol is essential for cellular health, supporting hormone production, membrane stability, and cellular signaling. However, disruptions in cholesterol movement between cell compartments may play a role in neurodegenerative diseases. The team’s CND probes enable real-time visualization of cholesterol in living cells, as detailed in a recent study published in Scientific Reports.

Using live-cell imaging and computer simulations, the researchers have shown how different probe designs influence cholesterol behavior. These findings may illuminate the connection between cholesterol imbalances and conditions like Alzheimer’s, paving the way for therapies that target lipid activity.

“With these probes, we can now visualize cholesterol movement and distribution in live cells with unprecedented detail,” notes Dr. Stawikowski.

The Science Behind CND Probes

The CND probes use a 1,8-naphthalimide (ND) scaffold known for its strong fluorescence characteristics, such as significant Stokes shifts and sensitivity to environmental changes. This modular design allows researchers to customize probes with specific head groups and linkers to suit various experimental goals.

Key findings include:

• Neutral probes: Readily aggregate but have limited cellular uptake.
• Charged probes: Show better solubility and improved interaction with cellular membranes.
• Hydroxyl-modified probes: Enhance hydrogen bonding and lipid interactions, making them particularly effective for studying membrane behavior.

Additionally, some variations of the probes are pH-sensitive, enabling the tracking of cholesterol movement in organelles such as lipid droplets and lysosomes, which have distinct acidity levels.

These advances offer better fluorescence characteristics and more precise cholesterol tracking compared to traditional probes, providing valuable insights into cellular functions.

Implications for Neurodegenerative Diseases

“Cholesterol is essential for brain function, but its dysregulation could be a key factor in disease progression. Our new tools provide a window into how cholesterol impacts cellular processes and may help identify therapeutic targets for conditions like Alzheimer’s,” says Dr. Stawikowski.

The potential applications of these probes extend beyond Alzheimer’s research. They could be used to study drug delivery, lipid dynamics, and membrane biology, broadening the understanding of lipid-related disorders.

A Promising Step Forward

By combining experimental methods with computer simulations, the FAU team has created adaptable tools for investigating the role of cholesterol in cellular health and disease. These advancements could significantly enhance research efforts across a range of lipid-related conditions, offering new opportunities to develop therapeutic interventions.