Grant: Discovery Grants Program - Individual

The blood-brain barrier is composed of specialized cells lining the blood vessels of the brain. This barrier provides the brain with a controlled environment optimal for brain function. The endothelial cells that comprise the barrier are tightly apposed in a manner that restricts diffusion of ions, small molecules and proteins across this cell layer. While the endothelial cells comprise the barrier, other cell types provide growth factors and signaling molecules that affect the function of the barrier. These other cell types include astrocytes and neurons. A new term, ""the neurovascular unit"", has been coined, to reflect the interconnections among these cells. The objectives of this proposal are to1. Develop cell culture models of the blood-brain barrier that consist of endothelial cells alone or in combination with astrocytes or astrocytes and neurons. 2. Compare these blood-brain barrier models for permeability in control and stimulated conditions. Permeability will be assessed by measuring the rate of transfer of different sized tracers (e.g. radiolabeled sucrose, MW 342, and fluorescent albumin, MW 66,000) across the endothelial cell monolayer. Agents that stimulate endothelial cells, astrocytes or neurons (e.g. cAMP, nitric oxide, potassium, sodium channel blockers) and their effects on permeability will be evaluated. 3. The signaling pathways involved in regulating blood-brain barrier permeability will be explored through assays of gene expression and protein function. The blood-brain barrier is a dynamic structure with regulated expression of receptors and transporters. Regulation of barrier function is difficult to study in vivo and current cell culture models lack a critical cell type, neurons. This project will examine the signals sent and the resulting responses among endothelial cells, astrocytes and neurons in response to agents that activate cell signaling pathways.