beta-amyloid-induced migration of monocytes across human brain endothelial cells involves RAGE and PECAM-1

Area of Science:

• Neuroscience
• Immunology
• Cell Biology

Background:

• Amyloid beta (Abeta) deposition and monocyte/microglia infiltration characterize Abeta-related cerebrovascular disorders, including Alzheimer's disease.
• The precise role of Abeta in monocyte trafficking across the blood-brain barrier (BBB) remains incompletely understood.

Purpose of the Study:

• To investigate the effect of Abeta on monocyte adhesion and transendothelial migration across human brain endothelial cells.
• To identify the molecular mechanisms and receptors involved in Abeta-mediated monocyte diapedesis.

Main Methods:

• Utilized human brain endothelial cell monolayers challenged with Abeta(1-40).
• Assessed adhesion and transendothelial migration of monocytic cells (THP-1, HL-60) and peripheral blood monocytes.
• Investigated the role of the receptor for advanced glycation end products (RAGE) and platelet endothelial cell adhesion molecule (PECAM-1) using antibodies.
• Examined the involvement of protein kinase C and phosphatase signaling pathways.

Main Results:

• Abeta(1-40) significantly increased monocyte adhesion and transendothelial migration across brain endothelial cells.
• Antibodies against RAGE and PECAM-1 inhibited Abeta-mediated monocyte migration.
• Protein kinase C inhibition reduced Abeta-induced migration, while phosphatase inhibition augmented it.
• Abeta interaction with RAGE on endothelial cells triggers signaling pathways crucial for monocyte diapedesis.

Conclusions:

• Abeta interaction with RAGE on brain endothelial cells initiates signaling cascades that promote monocyte transendothelial migration.
• Increased monocyte diapedesis across the BBB in response to Abeta may be a key factor in the pathophysiology of Abeta-related vascular disorders.
• Targeting the Abeta-RAGE interaction or downstream signaling could offer therapeutic strategies for these conditions.