Color Dependence of OLED Phototherapy for Cognitive Function and Beta-Amyloid Reduction through ADAM17 and BACE1

Area of Science:

• Neuroscience
• Biomedical Engineering

Background:

• Alzheimer's disease (AD) is characterized by amyloid-beta (Aβ) pathology.
• Previous studies indicated 40 Hz visual stimulation reduced Aβ levels in AD models.
• The distinct effects of different light colors on AD pathologies remain unclear.

Purpose of the Study:

• To investigate the color-dependent effects of optimized organic light-emitting diode (OLED)-based visual stimulation on cognitive function and Aβ pathology in 5xFAD mice.
• To explore the underlying mechanisms of light-induced therapeutic effects in an AD model.

Main Methods:

• Developed a uniform OLED visual stimulation platform.
• Administered acute and chronic visual stimulation with different light colors (white, red, green, blue) to 5xFAD mice.
• Assessed cognitive function, Aβ plaque accumulation, ADAM17 and BACE-1 activity, IL-1β levels, and c-fos expression.

Main Results:

• Acute white or red light improved cognition, reduced hippocampal Aβ plaques, and downregulated IL-1β in young 5xFAD mice.
• Chronic white and red light enhanced recognition memory in older 5xFAD mice.
• Red light uniquely reduced Aβ plaques by upregulating ADAM17 and suppressing BACE-1 without affecting neuroinflammation.
• Both acute white and red light enhanced c-fos expression, indicating neural activation.

Conclusions:

• Color-dependent visual stimulation, particularly with red light, shows promise as an electroceutical strategy for Alzheimer's disease.
• Red light offers a unique combination of memory enhancement, Aβ reduction, and anti-inflammatory effects.
• Modulation of ADAM17 and BACE-1 activities by red light is a key mechanism for Aβ plaque reduction.