The Ro52/SS-A autoantigen has elevated expression at the brain microvasculature

Area of Science:

• Neuroscience
• Immunology
• Molecular Biology

Background:

• The blood-brain barrier (BBB) regulates molecular traffic into the brain.
• Proteins mediating interactions between brain microvasculature and immunoglobulin G (IgG) are not fully understood.
• Ro52/SS-A is an identified IgG-binding protein and autoantigen associated with autoimmune conditions like Sjogren's syndrome and systemic lupus erythematosus.

Purpose of the Study:

• To identify proteins selectively expressed at the brain's blood-brain barrier.
• To investigate the role of Ro52/SS-A in mediating interactions with IgG molecules at the brain microvasculature.
• To explore the potential involvement of Ro52/SS-A in autoimmune diseases affecting the brain.

Main Methods:

• Expression cloning technique utilizing a bovine brain microvascular cDNA library.
• Characterization of Ro52/SS-A protein interactions with IgG molecules.
• Northern blotting to assess transcript enrichment in the brain's microvascular compartment.

Main Results:

• Successfully expression-cloned the Ro52/SS-A gene product from a bovine brain microvascular cDNA library.
• Ro52 protein demonstrated IgG-binding independent of antibody specificity, suggesting a general antibody receptor function.
• Ro52/SS-A transcript was found to be enriched in the brain's microvascular compartment.

Conclusions:

• Ro52/SS-A is selectively expressed in the brain microvasculature.
• The selective expression and IgG-binding properties of Ro52/SS-A suggest a role in brain vascular involvement in autoimmune diseases.
• Ro52/SS-A may function as a general antibody receptor at the blood-brain barrier.